Accepted Manuscript Synthesis, Spectroscopic Studies and Inhibitory Activity against Bactria and Fungi of Acyclic and Macrocyclic Transition Metal Complexes Containing a Triamine Coumarine Schiff Base Ligand A.A. Abou-Hussein, Wolfgang Linert PII: DOI: Reference:

S1386-1425(15)00084-0 http://dx.doi.org/10.1016/j.saa.2015.01.063 SAA 13231

To appear in:

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Received Date: Revised Date: Accepted Date:

17 September 2014 5 November 2014 25 January 2015

Please cite this article as: A.A. Abou-Hussein, W. Linert, Synthesis, Spectroscopic Studies and Inhibitory Activity against Bactria and Fungi of Acyclic and Macrocyclic Transition Metal Complexes Containing a Triamine Coumarine Schiff Base Ligand, Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy (2015), doi: http://dx.doi.org/10.1016/j.saa.2015.01.063

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

1 Synthesis, Spectroscopic Studies and Inhibitory Activity against Bactria and Fungi of Acyclic and Macrocyclic Transition Metal Complexes Containing a Triamine Coumarine Schiff Base Ligand A.A. Abou-Husseina and Wolfgang Linertb

a) Faculty of Women for Arts, Science and Education, Ain Shams University, Heliopolis, Cairo, Egypt. b) Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt, 9/163-AC, 1060 Vienna, Austria. Abstract Two series of new mono and binuclear complexes with a Schiff base ligand derived from the condensation of 3-Acetylcoumarine and diethylenetriamine, in the molar ratio 2:1 have been prepared. The ligand was characterized by elemental analysis, IR, UVvisible, 1 H-NMR and mass spectra. The reaction of the Schiff base ligand with cobalt(II), nickel(II), copper(II), zinc(II) and oxovanadium(IV) lead to mono or binuclear species of cyclic or macrocyclic complexes, depending on the mole ratio of metal to ligand and as well as on the method of preparation. The Schiff base ligand behaves as a cyclic bidentate, tetradendate or pentaentadentae ligand. The formation of macrocyclic complexes depends significantly on the dimension of the internal cavity, the rigidity of the macrocycles, the nature of its donor atoms and on the complexing properties of the anion involved in the coordination. Electronic spectra and magnetic moments of the complexes indicate that the geometries of the metal centers are either square pyramidal or octahedral for acyclic or macro-cyclic complexes. The structures are consistent with the IR, UV-visible, ESR, 1HNMR, mass spectra as well as conductivity and magnetic moment measurements. The Schiff base ligand and its metal complexes were tested against two pathogenic bacteria as Gram-positive and Gram-negative bacteria as well as one kind of fungi. Most of the complexes exhibit mild antibacterial and antifungal activities against these organisms.

Keywords: Hard-soft Schiff base, acyclic and macrocyclic complexes, spectral studies, antimicrobial activities. Corresponding Author: [email protected]

2 1. Introduction Coumarin was firstly isolated from Tonka tree beans and it contains a parent nucleus of benzo-α-pyrone [1]. The Schiff base ligands of coumarine and their metal complexes found paramount applications, they are well-known as antioxidants [2], pharmaceutical agents [3] and as luminescent materials [4]. They have pronounced medicinal value as anticoagulants [5], free radical scavengers [6] and

as

lipoxygenase

[7]

and

cyclooxygenase inhibitors [8]. Moreover, many coumarin derivatives exhibit high antibacterial [9], antifungal [10] and cytotoxic activities [11]. The coordination behavior of coumarin lactonic oxygen towards mono- or bimetallic transition metal depends on the reaction conditions and the substitutions on the coumarin moiety [12,13]. It is well known that Schiff-base ligands that are able to form binuclear transition metal complexes are useful in order to study the relation between structures, magnetic exchange interactions [14] and to mimic bimetallic biosites in various proteins and enzymes where the active sites contain two or more transition metal centers [15,16]. In continuation of our previous research [17] on synthesis and characterization of new asymmetric Schiff base complex, we describe here the synthesis and characterization of mono and binuclear complexes from Schiff base, HL derived from the 3acetylcoumarine (3-Ac) and ethylenetriamine (en) in the molar ratio 2:1. The ligand reacts with Co(II), Ni(II), Cu(II), Zn(II) and VO(IV) metal ions. Macrocylic complexes are prepared by the reaction between two moles of the Schiff base ligand with two moles of the metal salts in absolute ethanolic solution (ie. in the molar ratio 2:2). The Schiff base and their newly prepared metal complexes were identified by different physicochemical and spectroscopic techniques. The bacterial activity of the hard-soft Schiff base and their transition metal complexes have been investigated against two pathogenic bacteria (Staphylococcus aureus) as Gram-positive bacteria, and (Pseudomonas fluorescens) as Gram-negative bacteria in addition to one kind of fungi (Fusarium oxysporum) to assess their antimicrobial properties.

2. Experimental 2.1. Materials

3 The nitrate salts of cobalt(II), nickel(II) and zinc(II) are from obtained Merck or DBH. Copper(II)chloride dehydrate is from DBH. Vanadyl(IV)sulphate monohydrate was obtained from Aldrich. Organic solvents (absolute ethyl alcohol, methyl alcohol, acetone, dimethylformamide (DMF) and dimethylsulfoxide, (DMSO) are reagent grade and were used without further purification. 2.2. Physical Measurements Microanalyses of carbon, hydrogen and nitrogen were carried out on Perkin-Elmer 2400 Series II Analyzer. Electronic spectra of the metal complexes, in DMF solutions were carried out by using UV-VIS Perkin-Elmer Model Lamda 900. NIR IR and Midrange FTIR spectra of the compounds were recorded as KBr-pellets within the range 4000–400 cm-1 using a Perkin–Elmer 16PC FTIR spectrometer. Far FTIR spectra were recorded within the range 600–200 cm-1 on a Perkin–Elmer System 2000 spectrometer using polyethylene pellets. Analyses of the metals in the complexes were carried out complexometrically according to standard methods [18]. Mass spectra measurements were carried out on a Shimadzu-GC-Ms-QP, mass spectrometer model 1000 EX using a direct inlet system, at 220 ºC and 70 eV in the Micro Analytical Center, Cairo University, Egypt. 1

H-NMR spectra of the ligand Zn(II) as solutions in DMSO-d6, were recorded on a Bruker

WP 200 SY, spectrometer at room temperature using TMS as an internal standard, at national research center, Giza, Egypt. Magnetic susceptibilities of the complexes were measured at room temperature using a Johnson Matthey, Alfa Products, model MKI magnetic susceptibility balance. The effective magnetic moments were calculated from the expression µeff. = 2.828 (χM.T)1/2 B.M., where χM is the molar susceptibility corrected using Pascal’s constants for the diamagnetism of all atoms in the compounds [19]. ESR spectra of the copper complexes were recorded on a Bruker BioSpin GmbH spectrometer, at the Research Centre for Nuclear and Radiation Safety, Naser City, Cairo, Egypt. Molar conductivities were measured in DMF solutions of the complexes (10−3 M) using a model LBR, WTWD-812, Weilheim Conductivity meter fitted with a model LTA100 cell.

2.3. Synthesis of the Schiff Base, HL The Schiff base, HL ligand was prepared by addition of a solution of diethylenetriamine (1.50 g, 14.53 mmol) in ethanol (40 mL) to 3-Acetylcoumarine (3-AC) (5.47 g, 14.53 mmol) for HL in ethanol (40 mL) in the molar ratio 1:2. The solutions were refluxed for 3 h. Yellow crystals were formed on cooling the solutions slowly to room

4 temperature and the precipitates were collected by filtration, washed with ethanol, then with diethylether and finally air-dried. The yield was 4.19 g (60.11 %), m.p. 215 ºC. Figure 1 illustrates the synthetic scheme of the Schiff base, HL ligand.

Fig. 1. The synthetic scheme for the Schiff base , HL

2.4. Synthesis of the Transition Metal complexes of the Schiff Base, HL, Ligand 2.4.1. Preparation of mononuclear complexes: One mole of an ethanolic solution of the metal was added gradually with constant stirring to an ethanolic solution of one mole of the Schiff base, HL ligand. The reaction is refluxed for 2 h, where the solid complexes were precipitated and filtered off, washed with several portions of ethanol, then diethylether and finally air-dried. The complexes are air stable in the solid state, soluble in DMF and DMSO. The following detailed preparations of [Co(HL)(NO3)2].3H2O, 1 and [VO(HL)(H2O)2].SO4.2H2O, 5 and are given as examples for these reactions. The other complexes were obtained similarly. 2.4.1.1. Synthesis of [Co(HL)(NO3)2].3H2O, 1 A solution of Co(NO3)2.6H2O (2.50 g, 8.59 mmol) in ethanol (20 mL) was added gradually to a solution of the Schiff base HL ligand (3.23 g, 8.59 mmol) in ethanol (40 mL). The solution was stirred for 30 min. and heated to reflux for 2 h. The precipitate was formed on hot. The precipitate was filtered off, washed with ethanol, then diethylether and finally air-dried. The yield was 3.214 g (56.09 %). Figure 2. The synthetic scheme of [Co(HL)(NO3)2]

3H2O,1.

2.4.1.2. Synthesis of [VO(HL)].SO4.2H2O, 5 A solution of VOSO4.5H2O (2.50 g, 9.87 mmol) dissolved in the lowest possible amount of distilled water then diluted with ethanol to 40 mL was added gradually to a solution of the Schiff base, HL, ligand (3.717 g, 9.87 mmol) in ethanol (40 mL). The solution was stirred for 30 min and heated under reflux for 3 h. The precipitate was formed after cooling to room temperature. It was filtered off, washed with ethanol, then diethylether and finally air dried. The yield was 4.230 g, (68.34%). 2.4.2. Preparation of binuclear macrocyclic complexes A solution of the Schiff base HL in ethanol (40 mL) was added gradually to a solution of the respective metal salt in ethanol (40 mL) in the molar ratio 2:2 to obtain the metal complexes of the macrocyclic H2L ligand. The solutions were stirred

5 for 30 min and the heated under reflux conditions for 6 h. The solid complexes were precipitated and filtered off, washed with ethanol, then diethylether and finally airdried. The complexes are air stable in the solid state, soluble in DMF and DMSO. The following detailed preparations are given as examples for reactions to obtain binuclear metal complexes and the other compounds were obtained similarly. 2.4.2.1. Synthesis of [Ni2(HL)2(NO3)2].2NO3.2H2O, 7 A solution mixture of the Schiff base, HL (1.5 g, 1.6911 mmol) in ethanol (20 mL) was added gradually to a solution of the Ni(NO3)2.6H2O (0.983 g, 1,6911 mmol) in ethanol (40 mL) in the molar ratio 2:2, to obtain the nickel(II) complex of the macrocyclic H2L ligand. The solutions were stirred for 30 min, and heated to reflux for 6 h. The solid complexes were precipitated and filtered off, washed with ethanol then diethylether and finally air-dried. A green precipitates was formed which, yielding a product of the formula, [Ni2(H2L)(NO3)2].2NO3.2H2O. The complex is air stable in the solid state, soluble in DMF. The yield was 1.051 g, (42.32%), for the reaction. Figure 3. The synthetic scheme of [Ni2(HL)2(NO3)2].2NO3.2H2O. 2.4.2.2. Synthesis of [Cu 2(HL)2Cl2].2Cl.3H2O, 8 A solution mixture of the Schiff base, HL (1.5 g, 1.6911 mmol) in ethanol (20 mL) was added gradually to a solution of the CuCl2.2H2O (0.576 g, 1.6911 mmol) in ethanol (40 mL) in the molar ratio 2:2, to obtain the copper(II) complex of the macrocyclic ligand. The solutions were stirred for 30 min, and heated to reflux for 6 h. The solid complexes were precipitated and filtered off, washed with ethanol, then diethylether and finally airdried. The complex is air stable in the solid state, soluble in DMF and DMSO. The product obtained has the molecular formula, [Cu 2(HL)2Cl2] Cl2.4H2O 8.

The yield was

1.546 g, (74.47%). 2.5. Biological studies In vitro antibacterial activity studies were carried out by using the standardized disc-agar diffusion method [20] to investigate the inhibitory effect of the synthesized ligand and complexes against Gram-positive bacteria, such as Staphylococcus aureus (ATCC25923), Gram–negative bacteria: as Pseudomonas fluorescens (S97) and Fusarium oxysporum as a kind of fungi. The antibiotic chloramphencol was used as standard reference in the case of Gram–negative bacteria and cephalothin was used as standard

6 reference in the case of Gram–positive bacteria and cycloheximide was used as standard antifungal reference. An inhibition zone diameter indicates that the tested compounds are active against the used kinds of the bacteria and fungus. The studies are carried out at Faculty of Agriculture, Department of plant Pathology, Al-Azhar University. 3. Results and discussion It is worth noting that, the different preparative methods, mentioned above, leaded in most cases to the formation of metal complexes with identical molecular formula. The obtained metal complexes and their physicochemical properties are shown in Table I.

Table1. Physicochemical properties of the Schiff bases and the transition metal complexes.

3.1. Schiff Base, HL Ligand The Schiff base ligand was characterized by elemental analysis, infrared, UVvisible, mass spectra and 1H-NMR spectra. The infrared spectrum is consistent with the formation of the protonated HL species. The Schiff base ligand is obtained from the condensation of the carbonyl compound, (3-Ac) and diethylentriamine, DET in the 2:1 mole ratio. There are three main features in the infrared spectrum of the newly ligand. The first one is the disappearance of the characteristic carbonyl group of acetyl group at 1686 cm-1 of 3-Acetylcoumarine and –NH2 stretching vibration (3293 cm-1) of the DET and the appearance of the intense band at 1655 cm−1, which is assigned to the azomethine moiety, ν(C=N), and confirming the condensation. The band around the region 3242 cm-1 in free ligand is assigned to amide group ν(NH). The broadness of this band may be due to the intermolecular hydrogen bonding between the azomethine groups and the NH group [21] . The presence of carbonyl group in the infrared spectra gives rise to a band at 1723 cm-1 in the spectrum is readily assigned to C=O group of lactone stretching vibrations present in coumarin ring (pyrone) [22, 23]. On the other hand, the band observed at 1272 cm-1 is assigned to ν(C-O-C) of coumarine ring [24] while the band at 1264-1267 cm-1 is ascribed to ν(C-O) stretching vibrations and around the region from 1567 to 1483 cm-1 is assigned to the combination of ν(C=C) of the aromatic ring [25]. Electronic spectrum of the HL ligand showed absorption bands at 280, 300 nm which are assigned to π
π* transitions within the coumarine moiety [26]. The bands at 350 nm

7 attributed to π–π*transitions of the C=N and C=O in addition to a broad band at 410nm due to the n
π* transition which is overlapping with the intermolecular CT from the phenyl ring to the azomethine group [27]. Mass spectra were performed for HL Schiff base ligand to determine the molecular weights and fragmentation patterns. The molecular ion peaks were observed at 443 m/e confirming their formula weights. for ligand. The schematic fragmentation of the ligand is depicted in Figure 4.

Fig. 4. The schematic fragmentation of the Schiff base ligand HL.

3.2. Schiff Base Complexes of HL Ligand. 3.2.1. Infrared Spectra Infrared spectra of the complexes were recorded to confirm their structures. The vibration frequencies and their tentative assignments for HL ligand and their transition acyclic mononuclear and macrocyclic binuclear metal complexes are listed in Table 2. The assignments were aided by comparison with the vibrational frequencies of the free ligand and their related compounds. The infrared spectra of the mono and binuclear complexes exhibit broad bands around 3492-3378 cm-1 assigned for ν(OH) of water molecules associated with the complex formation which are confirmed by elemental analysis [28]

.

The infrared spectra for the acyclic mononuclear complexes Ni(II) and Cu(II) complexes show bands corresponding to NH group at 3236 at 3228 cm 1, respectively. This band was −

shifted towards lower frequencies compared to the ligand spectrum indicating the coordination of amino nitrogen to the metal ion [29] . On the other hand, the NH group presets at the same position for the acyclic complexes of Co(II) and Zn(II) and VO(IV) in addition to all dinuclear macrocyclic complexes, suggesting the non-involvement through the coordination sphere of the complexes, similar behavior have been observed [30]. The IR spectra of all complexes show a shift of the strong band of ν(C=N) towards lower frequencies compared to the free ligand HL [31, 32]. Therefore, the bonding occurs through the azomethine nitrogen atoms. Further evidence of the bonding is given by the observation of new bands in the spectra of the metal complexes of medium or weak intensity between 446-463 cm-1 region can be assigned to ν(M-N). [33] As previously stated the presence of lactonic carbonyl is confirmed by the appearance of a sharp band at 1723 cm−1 in the spectrum of the free ligand. This band is

8 shifted to (1713 – 1693 cm−1) in the spectra of the mononuclear complexes 3,4 and 5 as well as all binuclear macrocyclic complexes, indicating its involvement of oxygen atom of the lactonic carbonyl groups in the coordination sphere. Further evidence of the bonding is given by the appearance of new bands in the spectra of the metal complexes of medium or weak intensity between 533 and 554 cm-1 can be assigned to ν(M-O) [34, 35]. On the other hand, the spectra of mononuclear Co(II) and Ni(II) complexes, show another behavior where none of the carbonyl lacton groups involve into the coordination and remain unchanged [36, 37]. This observation is further supported where the stretching vibration assigned to ν(C-O-C) of chromane ring (i.e. 1272-1265 cm-1) remain nearly at the same position rules out the possibility of coordination through oxygen atom of the lacton ring of chromane moiety for previous the complexes [38]. For mononuclear VO(IV) complex, the strong band observed at 1720 cm-1 in the ligand, assigned to C=O, appears at the same position in the complex but much diminished in the intensity. In addition, there is a new band at 1686 cm-1 which may be attributed to the other coordinated lactone C=O group. This observation indicates that in VO(IV) complex, oxygen atom of lactone C=O of one part of HL coordinates to the metal atom, while other C=O remains free [39]. On the other hand, two bands were observed for the stretching frequencies of the azomethine groups that could be assigned to the coordinated and uncoordinated azomethine group at 1625 and 1585 cm-1, respectively which indicate that only single azomethine linkage is involved in the coordination [40]. Such behavior indicates that one part of the ligand is coordinated to metal atom through oxygen and nitrogen atoms while other part remains uncoordinated. The coordinating water in the VO2++ complexes is characterized by the appearance of ν(OH), ρr(H2O) and

ρ W(H2O)

vibrations at 3436-3450, 855-860 and ≈ 600 cm-1, respectively. Also, the stretching vibration at 535 cm-1 band, assigned to ν(M←OH2), supported for the participation of water in coordination [41]. The second most important features of the infrared spectra of some complexes are the coordination behavior of nitrate, chloride and sulphate anions. The IR spectra of the complexes show strong absorption bands which are consistent with monodentate or bidentate nitrate vibration. For complexes 1, 6 and 9 the nitrate anions behave as coordinated bidentate nature where nitrate possesses three non-degenerate modes of vibrations (νs, νs' and vas), at the range (1435-1458, 1257-1281 and 1023-1011 cm-1). The

9 separation of ≈ 200 cm-1 between ν s and νs' confirmed the bidentate nature of the nitrate groups [42]. On the other hand for complexes 2 and 7 the NO3- ions are coordinated to the metal ion as unidentate corresponding to C2v symmetry, with three non-degenerate modes of vibrations (νs, νs' and ν as), are appearing at the ranges 1436-1454, 1254-1263 and 10171026 cm-1, respectively. While for complexes 4, 6, 7 and 9 strong band at the range from 1373 cm-1 to 1380 cm-1 is observed and could be assigned to the stretching mode of the ionic nitrate [43]. For Cu(II) acyclic and macrocyclic complexes, 3 and 8 the coordination behavior of the chloride ions was investigated by the addition of AgNO3 solution to the complexes, the chloride ions are detected for both of them, [Cu(HL)]Cl2.(H2O)2 3 and, [(Cu)2(HL)2 (Cl)2].Cl2.(H2O)3, 8 where its ions were precipitated. However, for macrocyclic complex 8 a weak intensity band observed at 364 cm-1 which can be assigned to the stretching vibration of the coordinated chloride to the metal ion suggesting the presence of coordinated and uncoordinated chloride ions, this results further confirmed by the conductivity measurements [44,45]. The oxovanadium complex, 5 exhibits a strong band around 972-980 cm-1.This reflects the high π-band order of vanadium to oxygen link of VO+2 and indicate the presence of monomeric oxovanadium species [46]. On the other hand, for complex 10, a high intensity band at 990 cm-1 is observed. This could be attributed to dimerisation via V=0 which would be reflected by shifting the respective vibration [47]. Generally, the free sulfate ion belongs to the high symmetry point group Td and is expected to show only two fundamental IR active vibrations ν3(F2); i.e. νd(S-O), and ν4(F2), i.e. δd(O-S-O).The bands in the two regions 1124-1136 cm-1 and 623-634 cm-1 confirm the presence of an ionic sulphate for both the previous complexes [48]. This observation has been further supported by conductivity measurements. It is obvious that the bonding sites of the ligand to the metal ion are the nitrogen atoms of the azomethine groups and the lactonic oxygen for a mononucler complexes, except for Co(II) and Ni(II) coumarine complexes where the bonding chelation occur only through the azomethine groups. On the other hand for a mononuclear Cu(II) and Zn(II) the amide (NH) , azomethine (C=N) in addition to lactonic oxygen are the coordinating sites, while for vandayl complexe the chelation occurs through only one part side of the

10 complex through one azomethine and lacton groups. For the macrocyclic complexes the chelation occurs through the azomethgine groups as well as lactonic oxygen forming bridged dinuclear Schiff base complexes. The nitrate, sulfate and chloride as well as coordinated water molecules satisfy the other coordination sites to complete the geometry. of the central metal ion.

Table 2. Infrared frequencies of the main characteristic bands of the Schiff base ligand HL and acyclic and macrocyclic transition metal complexes. 3.3.3. Electronic Spectra, Magnetic Moments and Molar Conductivity Measurements It is possible to draw up the electronic transitions and predict the geometry with the aid of magnetic moments of most metal ions. Table 3, lists the characteristic electronic absorption bands, magnetic moments and molar conductance of the ligand and its metal complexes in DMF solutions.On complex formation the absorption bands undergo a bathochromic shift compared to the free ligands as a result of coordination. The electronic spectra of the Co(II) complexes of 1 and 6 consist of a band in the visible region, often with a shoulder on the low energy site. Since the 4A2g(F)  3T1g(F) transition is essentially a two electron transition from t2g5eg2 to t2g3eg4, it is expected to be weak, and the usual assignment is a shoulder from 4A2g(F)  4T1g(F) and 4T1g(P)  4

T1g(F) transitions. For mononuclear Co(II) complex, 1 , these bands are located at 660

(sh) and 575 nm, while dinuclear macrocyclic Co(II) complex, 6, showed two bands at 662 (sh) and 578 nm. These transitions are in agreement with the formation of a high spin octahedral geometry. Also, the magnetic moment provide a complementary means of octahedral geometry, the measured magnetic moments for these complexes are 5.14 and 4.91 B.M., respectively, which lie in the range of octahedral complexes (4.8–5.2 B.M.) [49.50]. Electronic spectrum of the Ni(II), 2 complex showed more intense doublet bands at 687 and 756 nm. These bands may be due to 3T1(P)  3T1(F) transition, which could occur in a tetrahedral d8 arrangement [51]. Generally, this band is expected to split by spin-orbital coupling to an extent which makes unambiguous assignments difficult. The magnetic moment was measured and equals 3.88 B.M., which lie in the range of tetrahedral compounds (3.2–4.1 B.M.). The magnetic and spectroscopic studies of bridged binuclear nickel complexes suggest a structure of nickel atoms in two different geometries. Its magnetic moment (0.85 B.M) is low comparing with the reported values

11 for tetrahedral or octahedral geometry [52]. This has been ascribed to the influence of spin-orbital coupling in "mixing" a spin singlet (1Eg) with the 3T1g(F) spin triplet, thereby allowing the spin-forbidden transition to gain intensity from the spin-allowed transition. The electronic spectrum in DMF shows bands at 652 and 405 cm-1 characteristic for octahedral geometry and attributed to the 3A2g-→3T1g (F) (ν2) and 3A2g→3T1g (P) (ν3) transitions, respectively. An additional broad band centered at 453 cm-1 is attributed to the 1

Ag→1A2g transition in a square-planar geometry. Previous studies on the Ni(II) complex

suggest a mixed geometry The present complex has yellowish green color supporting the previous supposition [53]. A square-pyramidal structure is proposed for complex 3, [Cu(HL)]Cl2.2H2O, based on the presence of two bands at 600 and 455 cm-1. This may be assigned to the 2

2

B1g →2A1g and

2

B1g →2Eg transition, respectively. Due to the low intensity, the

B1g →2B2g transition is not observed in the spectrum as a separate band [54]. The value of

the magnetic moment is in accordance with the previous results (1.68 BM). On the other hand, the electronic spectrum of the green dinuclear Cu2(II) complex, 8, showed one unsymmetrical band at 692 nm which is assigned to 3T2g(G)←Eg transition in distorted octahedral geometry. The broadness of the observed band may be due to Jahn-Teller distortion of the octahedral geometry [55]. The measured value of the magnetic moment for Cu(II) complex was 1.81 B.M., which is in agreement with the value of the octahedral geometry [56]. The reflectance spectrum of the oxovanadium complexes, 5 shows a well-defined two bands at 518 and 724 assigned to 1B2→2E and 1B2→2A1 in a square-pyramid structure configuration with effective magnetic moment 1.83 B.M [57]. The binuclear macrocyclic complex of oxovandium, 10, [(VO)2(HL)2(H2O)2].2SO4, exhibits subnormal magnetic moment (Meff 1.67 B.M) at room temperature. The unpaired electron in the 3dxy of vanadium ion is overlapped with the dxy orbital of the adjacent vanadium atom. Such an interaction leads to subnormal magnetic moment at room temperature. Absorption at 787 and 547 nm are observed and can be assigned to 2B2→ 2E(ν1) and 2B2→ 2B1(ν2) and attributed to distorted octahedral geometry [58]. Zn(II) complex 4 and 9 are of a diamagnetic as expected and its geometry is proposed to be octahedral for both the acyclic mononuclear and binuclear macrocyclic complexes [59]. The elemental analysis and the conductivity measurements are in accordance with the proposed geometry.

12 Molar conductivities of the complexes are recorded in DMF (1.0 X 10 -3 M). The conductivity data are in the range reported for 1:1 or 1:2 electrolytes. The elemental analysis agrees with the previous results. It has been reported that DMF is a good donor solvent has can be replaced by NO3- from the coordination sphere of the metal complexes. This leads to the coordination nitrate ion is exchanged with solvent and became free in the solution [60]. Table 3. Electronic absorption bands (nm), magnetic moments (B.M.) and molar conductivities (Ohm-1 cm2 mol-1) of transition metal complexes. Powder ESR spectrum were carried out for complex, 3 at room temperature with frequency at 9.723 Ghz and magnetic field set of 3459 G. The spin Hamiltonian parameters for [Cu(HL)] Cl2.(H2O)2 (S = 1/2, I = 3/2) were calculated. The g tensor values can be used to derive the ground state. In square-planar or square pyramidal complexes, the unpaired electron lies in the dx2– y2 orbital giving 2B1g as the ground state with g > g⊥ > 2.0023, while giving 2A1g with g⊥ > g > 2.0023 if the unpaired electron lies in the d z2 orbital. From the observed values, g (2.34) > g⊥ (2.05) > 2.0023 indicating that the copper site has a d x2–y2 ground state characteristic of a square pyramidal [61]. In axial symmetry, the g values are related by: G =( g – 2)/( g ⊥ –2) =4.According to Hathaway if G > 4, the exchange interaction between copper(II) centers in the solid state is negligible, whereas when G < 4, a considerable exchange interaction is indicated. The G value of the complex (6.8) suggesting the absence of exchange coupling between copper(II) centers in the solid state [62, 63]. The X-band ESR spectrum of a five-coordinated square pyramidal [VO(HL)(H2O)2].SO4.2H2O 5, gave a broad single with poorly resolved eight hyperfine lines corresponding to the usual parallel and perpendicular components of g- and hyperfine (hf) A-tensor eight line pattern, and shows that a single vanadium is present in the molecule, i.e. it is a monomer. The observed order in the parameters g⊥(2.11) > g║ (2.08) indicates that the unpaired electron is present in the dxy orbital with squarepyramidal geometry around the oxovanadium(II),d1 chelates [64]. 1

H-NMR chemical shifts of HL, ligand defines the possible different effects

which act on the shielding constant of protons. The hydrogen atoms present in the methyl group shows a sharp singlet peak which is in the up field. The electron withdrawing effect of acetyl group and electronegativity of oxygen atoms are̾ more pronounced on the

13 chemical shift of the coumarin ring protons. The electronegative oxygen atom present in the neighbor carbon atom deshield the proton which reduces the electron density resulted in down field chemical shift. The aromatic protons appeared down field singles and overlapped with the olefinic protons of coumarin moiety. It is observed that the signal due to the proton of NH still exist at the same positions on adding D2O indicating the nonionizable nature of this ligand. The 1H-NMR spectrum of HL ligand in DMSO-d6, Table 4, ̾̾ ̾

showed signals at δ(ppm) 2.42 (s,6H, CH3a,a‫;)׳‬1.60, 2.41 and 3.23 (m, 8H, 4CH2b,c,b‫׳‬,c‫;)׳‬ 10.12 (s, br,1H, NHd ); 8.48 (s, 1H, coum-He); 8.56 (s, 1H, coum-He‫ ;)׳‬7.76 (s, 1H, Ar̾̾̾ ̾

Hf);7.94 (s, 1H, Ar-Hf‫ ) ׳‬and 7.43-7.36 (m,6H, Ar-Hg,Hg‫׳‬,Hh,Hh Hi,Hi‫)׳‬. The 1H-NMR spectrum of [Zn(HL)(H2O)] .2NO3.H2O in DMSO-d 6 (Table IV) showed signals at δ(ppm) 2.40 (s, 6H, 2CH3a,a); 2.26 (m, 8H, 4CH2b), 3.23 (m, 8H, 4CH2b‫ ;)׳‬10.11 (s, br,1H, NHc ); 8.46 (s, 1H, coum-Hd); 8.55 (s, 1H, coum-Hd‫ ;)׳‬7.76 (s, 1H, Ar-He); 7.94 (s, 1H, Ar̾̾ ̾

He‫ )׳‬and 7.42-7.37 (m,6H, Ar-Hf,Hf‫׳‬,Hg,Hg‫׳‬,Hi,Hi‫[ )׳‬65]. The appearance of the signals due to methyl, imide groups and coumarine moity with downfield shielding with respect to the free HL ligand is interpreted as a sign of complexation of the Zn(II) ion by the imide group, carbonyl as well as the azomethine groups. Table 4. 1H-NMR chemical shifts (δ, ppm) of the Schiff base, HL , ligand and its Zn(II) complex (5) in DMSO-d6 Finally, from the interpretation of elemental analysis, spectral data and magnetic studies as well as the thermal analysis and molar conductivities measurements, it is possible to draw up the tentative structures of the transition metal complexes. Figure 5 and 6 depicts the proposed structures of the metal complexes. Fig 5. Representative structures of the acyclic mononuclear metal complexes. Fig 6. Representative structures of the macrocyclic binuclear metal complexes. 3.2.6. Biological studies: The Schiff base, HL, ligand and its metal complexes were evaluated for antimicrobial activity against one strain Gram-positive bacteria Staphylococcus aureus and Pseudomonas fluorescens as Gram-negative bacteria as well as one pathogenic fungus, as Fusarium oxysporum. The results of the biological studies of the ligand and the complexes are shown in Table 5. The data are compared with standard antibiotics, chloramphencol as Gram-negative and cephalothin as standard reference for Gram–positive bacteria.

14 Cycloheximide was used as antifungal standard reference. The in vitro antibacterial and antifungal activities demonstrated that complexes have higher antimicrobial activity in comparison with that of the ligand. According to Tweedy’s theory [66], chelation reduces the polarity of the metal atom because of partial sharing of its positive charge with a donor group and the possible π-electron delocalization over the whole chelate ring [67]. Such a chelation could enhance the lipophilic character of the central metal atom, which subsequently favors its permeation through the lipid layers of the cell membrane and blocking the metal binding sites on enzymes of microorganism [68, 69]. There are other factors which also increase the activity, such as solubility, conductivity and bond length between the metal and the ligand. It is worth to mention that, the ligand showed moderate biological activity against the tested strains and the complexes show higher bacterial activity as compared to the fungus. The result revealed also that complexes of Cu(II) displayed the maximum (significant) inhibition against the growth of the selected Gram-positive, Gram-negative bacteria and fungi followed. In contrast, Co(II), Ni(II), Zn(II) and VO(IV) complexes show moderate activity. From the data, the structure activity relationships showed that the binuclear macrocyclic enhances the antimicrobial activity rather than the acyclic complexes.

Table 5. Antimicrobial activity of the Schiff base ligand HL and its metal complexes. 4. Conclusions The Schiff base derived from the condensation of 3-acetylcoumarine and diethylenetriamine is a versatile ligand yielding two series of mono- or bi-nuclear complexes of varying geometries. The ligand acts as hexadentate or neutral tetradentate chelate for acyclic complexes and behave as neutral hexadentate or tetradentate for macrocyclic complexes. From the infrared spectra it can be seen that the chelation of the acyclic mononuclear metal ions to the ligands occurs through the nitrogen atoms of the azomethine groups of the ligands and the lactonic oxygen or imide group. On the other hand, in case of the macrocyclic binuclear species, the bonding sites are the azomethine groups and lactonic oxygen. The nitrate ions, sulphate, chloride, crystalline or coordinated water molecules satisfy the other coordination sites to complete the geometry around the central metal ion. The spectral, magnetic studies and molar conductivity measurements of the metal complexes were used to determine the type of coordination and the geometry

15 around the central metal ion. Acyclic and macrocyclic complexes exhibit tetrahedral, square pyramidal or octahedral geometry. Synthesized Schiff base and their corresponding metal complexes were tested for the growth inhibitory activity against phytopathogenic bacteria and fungi, including some, which are antibiotic resistant. This makes investigated species candidates for a practical use as antimicrobial agent. It is obvious that the metal complexes are more toxic against bacteria and fungi in comparison to their parent. The

growth of single crystals of these complexes for X-ray studies is very difficult owing to their amorphous nature and we were unsuccessful in our attempts to do so.

References: [1]

S. M. Sethna, N. M. Shah, Chem. Rev.,1945, 36

[2]

H. Sies, Exp Physiol, 82 (1997) 291.

[3]

R. O’Kennedy, R. D. Thornes,Coumarins: biology, applications, and mode of action, John Wiley & Sons, Chichester; New York, 1997.

[4]

S. J. Bullock, C.E. Felton , R.V. Fennessy, L. P. Harding,M. Andrews SJA Pope , C. R. Rice, T. Riis-Johannessen, Dalton Trans, 47(2009)10570.

[5]

A. Ghazaryan , A. Khatchadouria , M. Karagyozyan , A. Kachatryan , E. Sekoyan ,H. Bdoyan , H. Melkumyan , K. Karageuzyan : Peculiarities of the anticoagulant properties for the newly synthesized preparations of coumarin related compounds. Cardiovasc Hematol Disord Drug Targets, 7(2007)170.

[6]

V. D. Kancheva, P.V. Boranova, J. T. Nechev, I.I Manolov, 92(2010)1138.

[7]

GDT Morabito, B. Singh, A.K. Prasad, V. S. Parmar, F. M. Naccari, A. Saija, M. Cristani, O. Firuzi, L. Saso, Biochimie, 92 (2010) 1107.

[8]

E. Grimm, C. Brideau, N. Chauret, C. Chan, D. Delorme, Y. Ducharme, D. Ethier,J. Falgueyret ,R. Friesen, J. Guay, Bioorg Med Chem Lett.,16 (2006) 2528.

[9]

D. Lafitte, V. Lamour, P.Tsvetkov, A. Makarov, M. Klich, P.Deprez, D.Moras,C. Briand, R. Gilli, Biochemistry , 41(2002)7217.

[10]

C. Montagnev, S.de Souza, C. Groposoa, F. Delle Monache, E. Smania, A.J. Smania ,Biosci, 63 (2008) 21.

[11]

I. Kostova. Curr. Med. Chem Anti Canc Agent, 5(2005) 29.

[12]

M. P. Sathisha, U.N. Shetty, V.K. Revankar, K.S.R. Pai, Eur. J. Med. Chem., 43 (2008) 2338.

16

[13]

S. Budagumpi, V. K. Revankar, Spectrochimica Acta Part A, 77(2010)184

[14]

A. A. Abu-Hussein, and W. linert, Spectrochimica Acta Part (A), 117(2014)763.

[15]

A. A. Saleh, J. Coord. Chem. 58 (3) (2005) 255.

[16]

A. A. A. Emara and A. A. Abu-Hussen, Spectrochemica Acta Part (A), 64(2006) 1010.

[17]

A. A. Abu-Hussein, and W. linert, Spectrochim. Acta Part (A) 95 (2012) 596.

[18]

T.S. West, Complexometry with EDTA and Related Reagents, 3rd ed., DBH Ltd., Pools, London, 1969.

[19]

F. E. Mabbs, D.T. Machin, Magnetism and Transition Metal Complexes, Chapman and Hall, London, 1973, pp 5–6.

[20]

A.W. Bauer, W.W.M. Kirby, J.C. Sherris, M. Turck, Am. J. Clin. Pathol. 45 (1966) 493.

[21]

L. J. Bellamy, The infra-red spectra of complex molecules. 3rd Edition, Chapman and Hall, London, (1975).

[22]

M. V. Girgaonkar, S.G. Shirodkar , Res. J. Recent. Sci., 1(ISC-2011), (2012) 110.

[23] [24]

M. Rajeshirkea, R. Shaha, P. Yadavb and N.V. Purohita, Der Pharmacia Sinica, 3(2) (2012) 239. N. G. Alawandi, V. M. kulkarni, Indian J. of Chem., 45 (2006) 258.

[25]

B. S. Creaven, M. Devereux, D. Karcz, A. Kellett, McCann, M.,A. Noble, and M.Walsh, Journal of Inorganic Biochemistry, 103 (2009) 1196.

[26]

P. Kapoor, N.Fahmi, R.V. Singh, Spectrochimica Acta Part (A) 83 (2011) 74.

[27]

A. I. Mosa , Adel A. A. Emara, J. M. Yousef , A. A. Saddiq, Spectrochimica Acta Part (A), 81 (2011) 35.

[28]

F. X. Webster and R. M. Silverstein, Spectrophotometric Identification of Organic Compounds, 6th Ed, Wiley, New York, (1992).

[29]

B. Geeta , K. Shravankumar, P. Muralidhar Reddy, E. Ravikrishna, Spectrochimica Acta Part (A), 77(2010)911.

[30]

M. P. Sathisha, Ullas N. Shetti, V. K. Revankar K.S.R. Pai, European Journal of Medicinal Chemistry,4 3 (2008) 2338.

[31]

Adel A. A. Emara, Spectrochimica Acta Part (A), 77 (2010) 117.

[32]

A. A. A. Abu-Hussen, W. Linert, Spectrochim. Acta Part (A), 74 (2009) 214.

17

[33]

J. R. Ferraro, Low Frequency Vibrations of Inorganic and Coordination Compounds, second ed., John Wiley, New York, 1971.

[34]

R. S. Hunoor, B. R. Patil , D. S. Badiger, R. S. Vadavi, K. B. Gudasi, V.M. Chandrashekhar, I.S. Muchchandi, Spectrochimica Acta Part (A), 77 (2010) 838.

[35]

A. A. Abu-Hussen, W. linert. J. Coord. Chem., 1-12, (2009)

[36]

M. S. Refat, I. M. El-Deen, Z. M. Anwer , Samir El-Ghol, Journal of Molecular Structure, 920 (2009)149.

[37]

N. S. Youssef, E. El-Zahany, Ahmed M.A. El-Seidy, A. Caselli , S. Cenini, Journal of Molecular Catalysis A: Chemical, 308 (2009)159.

[38]

M. B. Halli, P. V. Reddy, Sumathi R. B1 and Basavaraja, Der Pharma Chemica, 4(3) (2012)1214.

[39]

M. P. Sathisha, U. N. Shetti, V. K. Revankar, K.S.R. Pai, European Journal of Medicinal Chemistry, 43 (2008) 2338.

[40]

A. A. Abu-Hussen, A. A. A. Emara, J. Coord. Chem., 57(11) (2004) 973.

[41] S. M. E. Khalil, H.S. Seleem, B.A. Shetary and M. Shebl, Coord. Chem., 55(8), 883 (2002) [42] K. Nakamoto, P. J. Mccarthy Spectroscopy and Structure of Metal Chelate Compounds, in: (Eds.), John Wiley, New York, 1968. [43]

A. A. A. Emara, B. A. El-Sayed , El-Sayed A.E. Ahmed, Spectrochimica Acta Part (A), 69 (2008) 757.

[44]

A. A. Abu-Hussein, W. Linert, Spectrochim. Acta Part (A) 95 (2012) 596.

[45]

A. A. El-Asmy, A.Z. Al-Abdeen, W. M. Abo El-Maaty, M.M. Mostafa Spectrochimica Acta Part (A), 75 (2010) 1516.

[46]

J. Selbin J. Chem. Educ. 41(1964) 66.

[47] M. S. Yadawe et al., Elixir Appl. Chem. 42 (2012) 6213. [48] N. M. El-Metwally, I. M. Gabr, A. A. El-Asmy, A. A. Abou-Hussen, Trans. Met. Chem.,31 (2006) 71. [49]E. Pretsch, J. Seible, Tables of Spectral Data for Structure Determination of Organic. Compounds, Springer-Verlag, Berlin, 1983. [50] A. B. P. lever, crystal field spectra, Inorganic Electronic Spectroscopy, 1st ed, Elsevier. Amsterdam, (1968).

18

[51] D. M. L. Goodgame , M. Goodgame , F. A. Cotton, J. Am. Chem. Soc., 83(20) (1961) 4161. [52] D. N. Satyanarayana. Electronic Absorption Spectroscopy and Related Techniques, University Press India Limited, New Delhi, 2001. [53] N.M. El-Metwally, A.A. Abu-Hussen, I.M. Gaber and A.A. El- Asmy, Transition Metal Chemistry, 31, 71-78 (2006). [54] A.A.A. Emara, A. A. Saleh and O. M.Z. Adly Spectrochimica Acta, Part (A), 68 (2007) 592. [55 ]

A. A. Abu-Hu ssein, J.Coord. Chem., 59 (2006) 157 .

[56]

A. B. P. Lever, Inorganic Electronic Spectroscopy, 2nd ed., Elsevier,Amsterdam,1997.

[57]

N.M. El-Metwally, R.M. El-Shazly, I.M. Gabr, A.A. El-Asmy, Spectrochim. Acta (A), 61 (2005) 1113.

[58]

S. Chandra, Sangeetika, Spectrochim. Acta (A) 60 (2004) 2153.

[59]

Saeed-Ur-Rehman, Muhammad Ikram, Sadia Rehman, Nazar Ul Islam, and Nazir Jan, J. Mex. Chem. Soc. 55(3)(2011)164.

[60]

W. J. Geary, Coord. Chem. Rev. 7 (1971) 18.

[61]

D. Kivelson, R. Neiman, J. Chem. Phys, 35(1961) 149.

[62]

B. T. Hathway, Struct. Bonding, 14(1973) 60.

[63]

M. R. Malachowski, B. Dorsey, J. G. Sackett, R.S. Kelly, A. L. Ferko, R.N. Hardin. Inorg. Chim. Acta, 249(1996) 85.

[64]

J. Costa Pessoa, I. Cavaco, I. Correic D. Castal, R. T. Henriques, R.D. Gillard. Inorg. Chem. Acta, 7 (2000) 305.

[65]

Rekha S. Hunoor , Basavar j R. Patil , Dayanand S. Badiger , Ramesh S. Vadavi , Kalagoud B. Gudasia, V.M. Chandrashekhar , I.S. Muchchandi ,Spectrochimica Acta Part (A) 77 (2010) 838.

[66]

B. G. Tweedy, Phytopathology, 55(1964) 910.

[67]

S. C. Singh Jadon, N. Gupta, R.V. Singh, Ind. J. Chem. 34A (1995) 733.

19 [68]

M.J. Pelczar, E.C.S. Chan, N.R. Krieg, Microbiology, 5 th Ed, McGraw-Hill, New York, (1998).

[69]

A.A. Abou Hussein, S.S. El-Kholy, M. Z. El-Sabee, J. Coord. Chem. 57(2004) 1027.

Figure 1. The synthetic scheme of the Schiff base, HL

O

+ O

N H2N

O

Two moles of 3-Acetylcoumarine

NH

NH2

One mole of diethylenetriamine

O

NH

O

N O

Schiff base HL

O

Figure 2. The synthetic scheme of [Co(HL)(NO3)2]3H2O,1.

N

NH

N

O

O

O

Schiff base HL

O

N H

N

+ CoNO3 .6H2O O

O

Co

O

N

O

N

O

O O

3H20 O

N O

[Co(HL)(NO3)2].3H2O

O

NH

N

O

N

O

O

O

443.18 [443; 13%] b O

CH3

.

O

H2C

.

NH

-CH3

N

+

a

a

N

O

O

O

O

CH3

257.13 [257; 67.1 %]

186 [186; 43.12 %] CN

-CO

CH3

171.03 [171; 71,14 %] - 1/2 (CN)2 +H

H N

+

+

N

O

O

O

O

187.06 [187; 74%]

O

158.06 [158; 77.12%] -1/2 N2

146.04 [146; 48.03 %] -CO -1/2 O2

+

+

N

- CH3CN -H

a

.

O

.

a O

O

b

.

173.05 [173; 31.11%] 132.08 [132; 68.21%]

129 [130; 39.12 %] O

-1/2 O2

CHCN

b

O

145.04 [145; 44.02 %]

O

-CO

+

.

91.13 [91; 55.23 %]

-CH=CN 157 [157; 66 .32 %]

O

118.04 [118; 58.31%] -1/2 HCCH C4H4 64 [63; 23.15%]

m/z 51 [51; 20 %]

Figure 4. The schematic fragmentation of the Schiff base ligand HL. Calc[Found,% of intensity]

N O

NH

ONO2

O

Co

O N

O

O

O

O

Co

ONO2 NH

O

N

2NO3.H2O

N

(6) [Co2(H2L)(NO3)2].2NO3.H2O

N O

O

O

NO3

Ni

N

Ni

NO3 NH

O

NH

N

O

O

O

O

2NO3.2H2O

N

(7) [Ni2(H2L)(NO3)2]2NO32H2O

N O

NH

Cl

O

Cu

Cu

O

Cl NH

O

N

N

O

O

O

O

2CL.3H2O

N

(8) [Cu2(H2L)(Cl)2].2Cl.3H2O

N O

O

O

Zn

O N

O

O

N O O

N O

Zn

NH

O

NH

N

O

O

O

O

2NO3.3H2O

N

(9) [Zn2(H2L)(NO3)2]2NO33H2O

N O

O

O

V N

H2O

N O2H

O

O

NH

O

NH

V

O

O

O

O

2SO4

N

(10) [(VO)2(H2L)(H2O)2].2SO4

Fig 6. Representative structures of the macrocyclic binuclear metal complexes.

Figure 3. The synthetic scheme of [Ni2(HL)2(NO3)2].2NO3.2H2O.7

O

O

O

N

N O O

N

NH

O

NH

O O

+ NiNO3 .6H2O

N

Two moles of Schiff base, HL

O

O

O

O

Ni

N O

Ni

O

ONO2 N

Two moles of Ni(II)

NH ONO2

NH

N

N

[Ni2(H2L)(NO3)2].2NO3.2H2O

O O

2NO3 3H2O

N H

N O

O

N

Co

O

O

O

O

O

O

N

3H20

N O

O

 

(1) [Co(HL)(NO3)2].3H2O   N H

N O

N

2H2O

Ni

O

O

O

NO3

O3N

(2) [Ni(HL)(NO3)2]2H2O NH N

N

Cu (Cl)2 2H2O

O

O

O

O

 

(3) [Cu(HL)]2Cl.2H2O

NH

N

N

Zn O

H 2O

O

(NO3)2.H2O O

O

(4)[Zn(HL)(H2O)].2NO3.H2O                    

O

O

H3C N

N

NH H3C

H2O

O

2H2O.SO4

V O O

H2O

(5) [VO(HL)(H2O)2].2H2O.SO4. Fig 5. Representative structures of the acyclic mononuclear metal complexes

Table 1. Physicochemical properties of the Schiff base ligand and its transition metal complexes. Ligand / Complex

M.F.

M.Wt.

Color

D.P. ºC

60.11

Yellow

174

HL

C26H25N3O4

(1)

[Co(HL)(NO3)2].3H2O

C26H31N5O13Co

680.125

56.09

Broun

> 250

(2 )

[Ni(HL)(NO3)2]2H2O

C11H21N11O17Ni

662.236

65.42

Green

> 250

(3)

[Cu(HL)]2Cl.2H2O

C26H29N3O6Cl2Cu

613.984

55.15

Violet

> 250

(4)

[Zn(HL)(H2O)].2NO3.H2O

C26H29N5O12Zn

668.933

53.61

white

> 250

(5)

[VO(HL)(H2O)2].SO4.2H2O

C26H33N3O13SV

678.568

68.11

Green

> 250

(6)

[Co2(H2L)(NO3)2].2NO3.H2O C52H52N10O21Co2

1270.91

61.26

Broun

> 250

(7)

[Ni2(H2L)(NO3)2]2NO32H2O

C52H54N10O22Ni2

1288.44

42.32

Green

> 250

(8)

[Cu2(H2L)(Cl)2].2Cl.3H2O

C52H56N6O11Cl4Cu2

1209.94

74.47

Blue

> 250

(9)

[Zn2(H2L)(NO3)2]2NO33H2O C52H56N10O23Zn2

1319.83

65.11

White

> 250

(10)

[(VO)2(H2L)(H2O)2].2SO4

1248.17

53.48

Green

> 250

I

C52H54N6O20S2V2

443.18

Yield (%)

%C 70.71 (70.21) 45.89 (45.91) 20.71 (20.28) 50.86 (50.48) 46.68 (47.13) 46.02 (49.43) 49.14 (49.65) 48.47 (48.41) 51.62 (51.38) 47.32 (46.84) 50.00 (51.44)

Elemental Analysis %H %N 5.86 9.47 ( 5.61) (9.44) 4.59 10.29 (4.20) (10.86) 3.32 24.15 (3.67) (24.53) 4.76 6.84 (4.82) (6.51) 4.37 10.47 (4.33) (10.64) 4.90 6.19 (4.63) (6.97) 4.12 11.02 ( 4.55) (11.26) 4.22 10.87 (4.31) (10.53) 4.66 6.95 (4.64) (6.58) 4.28 10.61 (4.04) (10.78) 4.36 6.73 (3.84) (6.38)

%M 8.66 (8.27) 9.20 (9.97) 10.36 (11.53) 9.78 (10.67) 7.51 (8.54) 9.27 (9.65) 9.11 (9.57) 10.50 (11.18) 9.91 (9.47) 8.16 (9.08)

21

Table 2. Infrared frequencies of the main characteristic bands of the Schiff base ligand and its transition metal complexes. Ligand / Complex I

HL

/(H2O)

(NH)

(C=N)

-

3242 br

1655s

1723 s

-

(C=O)lactone

(M-N)

(M-O) -

Other assignments 1272 s, ν(C-O-C) 1458(νs), 1281( νs), 1224(νas) Bidentate NO3 group

(1)

[Co(HL)(NO3)2].3H2O

3470 m, br

3240 s

1648 s

1726 s

460 m

-

(2 )

[Ni(HL)(NO3)2]2H2O

3378 s, br

3243 s

1650 s

1723 s

453 m

-

1436 s, 1263 s, 1026 as Unidentate NO3 group

(3)

[Cu(HL)]2Cl.2H2O

3365 s, br

3236 s

1642 s

446 s

546 m

ionic chloride complex

(4)

[Zn(HL)(H2O)].2NO3.H2O

3370 s, br

3228 s

1639 s

1710 s

460 m

538 m

1378 s, ionic NO3 group

(5)

[VO(HL)(H2O)2]SO4.2H2O

3484 s, br

3242 s

1625 s, 1585 s

1686 m 1720 s

448 m

533 m

985 m, ν(VO) 1130 br, 623 m ν(ionic SO4)

(6)

[Co2(H2L)(NO3)2]2NO3.H2O

3393 s, br

3244 s

1632 s

1693 s

463 m

446 m

1435(νs), 1257( νs),1178(νas) Bidentate NO3 group

(7)

[Ni2(H2L)(NO3)2]2NO32H2O

3463 s, br

3243 s

1589 s

1704 s

448 m

550 m

1454 s, 1254 s, 1017 as Unidentate NO3 group

(8)

[Cu2(H2L)(Cl)2]2Cl.3H2O

3480 s,br

3244 s

1590 s

1700 s

450 m

541 m

ν (C-Cl) 364

[Zn2(H2L)(NO3)2]2NO33H2O

3392 s, br

3242 s

1673 s

1705 s

456 m

552 m

[(VO)2(H2L)(H2O)2]2SO4

3470 s, br

3243 s

1596 s

455 m

554 m

(9) (10)

1713 s

1695s

strong, w = weak, m = medium, and br = broad, s : A single degenerate state which is symmetrical about the principle axis as: Antisymmetrical state with respect to the three C2v axis, s: A symmetrical state with respect to the three C2v axes.

1443(νs), 1256( νs), 1187(νas) Bidentate NO3 group 985 w, ν(VO) 1130 br, 623 m ν(ionic SO4)

21

Table 3. Electronic absorption bands (nm), magnetic moments (B.M.) and molar conductivities (Ohm-1 cm2 mol-1) of the Schiff base ligand HL and their transition metal complexes. complex

Electronic absorption bands ( nm) and their assignment d – d Transition d – d Transition µeff a assignment (B.M.)

(1)

[Co(HL)(NO3)2].3H2O

565, 660

4

(2 )

[Ni(HL)(NO3)2].2H2O

687, 756

3

(3)

[Cu(HL)]Cl2.2H2O

600,455

(4)

[Zn(HL)(H2O)](NO3)2.H2O

---

(5)

[VO(HL)(H2O)2]SO4.2H2O

518,724

T1(P) ← 4A2(F)

5.14

146

T1g(P) ← 3T1(F)

3.88

-

B1g →2A1g B1g →2Eg

1,68

166

Diamagnetic

-

145

B22E and 1B22A1

1.83

96

(6)

[Co2(H2L)(NO3)2](NO3)2.H2O

578, 665

4.91

248

(7)

[Ni2(H2L)(NO3)2](NO3)2.2H2O

652,405

(8)

[Cu2(H2L)(Cl)2]Cl2.3H2O

(9)

[Zn2(H2L)(NO3)2](NO3)2.3H2O

(10)

[(VO)2(H2L)(H2O)2](SO4)2

2

2

1

(b )

-

252

692

T1(P) ← 4A2(F) 3A2g-3T1g (F) (ν2) 3A2g3T1g (P) (ν3) 3T2g(G)←Eg

1.81

146

---

Diamagnetic

-

257

B22E and 1B22A1

1.67

139

547,787

4

1

(a) µeff is the magnetic moment of one cation in complex. (b) Molar conductivities were measured in DMF solvent with concentration x 10-3 M. Values are in Ohm-1 cm2 mol-1. (c) Values of max are in parentheses and multiplied by 10-4 (mol-1 cm-1).

21

Table 4. 1H-NMR chemical shifts (, ppm) of the Schiff base, HL , ligand and its Zn(II) complex (5) in DMSO-d6 c'

b'

a'

i'

e'

b'

h'

N

c'

c NH

d g' f'

O

a'

a

O

b

e

c

b a

NH

N

i

N

Zn O

h

N

d

e

O

e' *H2O

O

O

g

O

i'

O

i

f f'

h'

g

g'

H2L

h

f

Complex, 4 [Zn(HL)(H2O)].2NO3.H2O Chemical shift, δH (ppm)

HL

2.42 1.60,2.41,3.23 10,12 8.48, 8.56 7.76, 7.94 7.43-7.36

Assignment [Zn (HL)(H2O)].2NO3.H2O (4)

2.40 1.60,2.41,3.23 10,11 8.46, 8.55 7.76, 7.94 7.42-7.37

Ha, Ha’ [s, 6H,CH3] Hb, Hb’,Hc, Hc’ [m, 8H, CH2] Hd [s,1H br, NH] He, He’[s,2H, Coum-H] Hf ,He’ [s, 2H, Ar-H] Hg, Hg’,Hh, Hh’,Hi, Hi’ [s, 6H, Ar-H]

s = singlet; m= multiple, br broad, * (4.21 δH ppm) signal due to coordinated water

21

Table 5. Antimicrobial activity of HL, Schiff base ligand and its metal complexes Mean of zone diameter ,mm. mg mL—1 Gram - positive bacteria (b)

Compound

Staphylococcus aureus I HL (1) [Co(HL)(NO3)2].3H2O

(a)

Gram - negative bacteria (b) Pseudomonas phaseolicol

Fungi(b) Fusarium oxysporium

21

14 26

9 15

(2) [Ni(HL)(NO3)2]2H2O

18

22

11

(3) [Cu(HL)]2Cl.2H2O

23

27

19

(4) [Zn(HL)(H2O)].2NO3.H2O

23

23

13

(5)[VO(HL)(H2O)2].SO4.2H2O

16

20

13

(6)[Co2(H2L)(NO3)2].2NO3.H2O

28

32

23

(7)[Ni2(H2L)(NO3)2]2NO32H2O

25

30

19

(8)[(Cu)2(H2L)(Cl)2].2Cl.3H2O

37

35

21

(9)[Zn2(H2L)(NO3)2]2NO33H2O

30

32

24

(10)[(VO)2(H2L)(H2O)2].2SO4

34

39

25

(d)

Antibiotic

42

36

40

(a) Calculated from three average values. (b) Chloramphencol in the case of Gram-positive bacteria, Cephalothin in the case of Gram-negative bacteria and Cycloheximide in the case of fungi. (c) Error limits , ±. (d) Control. 21

Highlights Schiff base complexes derived from condensation of 3-Acetylcoumarine and diethylenetriamine were synthesized. The complexes are characterized by different spectroscopic techniques. The complexes have different varieties of geometrical structures. Biochemical studies were performed.

Graphical Abstract: Synthesis, Spectroscopic Studies and Inhibitory Activity against Bactria and Fungi of Acyclic and Macrocyclic Transition Metal Complexes Containing a Triamine Coumarine A.A. Abou-Hussein and Wolfgang Linert

NH N

N

Cu O O

(Cl)2 2H2O

O

O

[Cu(HL)]Cl2.2H2O

Structure of Cu(II) Schiff base ligand derived from the condensation of 3-Acetylcoumarine and diethylenetriamine