Charge-Transfer Supra-Amphiphiles Built by Water-Soluble Tetrathiafulvalenes and Viologen-Containing Amphiphiles: Supramolecular Nanoassemblies with Modifiable Dimensions.

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Amphiphiles

Charge-Transfer Supra-Amphiphiles Built by WaterSoluble Tetrathiafulvalenes and Viologen-Containing Amphiphiles: Supramolecular Nanoassemblies with Modiﬁable Dimensions Zhong-Peng Lv, Bin Chen, Hai-Ying Wang, Yue Wu, and Jing-Lin Zuo*

In this study, multidimensional nanoassemblies with various morphologies such as nanosheets, nanorods, and nanofibers are developed via charge–transfer interaction and supra-amphiphile self-assembling in aqueous phase. The charge–transfer interactions between tetrathiafulvalene derivatives (TTFs) and methyl viologen derivatives (MVs) have been confirmed by the characteristic charger-transfer absorption. 1H NMR and electrospray ionizsation mass spectrometry (ESI-MS) analyses also indicate supra-amphiphiles are formed by the combination of TTFs and MVs head group through charge–transfer interaction and Coulombic force. X-ray single crystal structural studies, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) reveal that both linkage pattern of TTFs in hydrophilic part and alkane chain structure in hydrophobic part have significant influence on nanoassemblies morphology and microstructure. Moreover, gold nanoparticles (AuNPs) are introduced in the above supramolecular nanoassemblies to construct a supra-amphiphile-driven organic-AuNPs assembly system. AuNPs could be assembled into 1D–3D structures by adding different amount of MVs.

1. Introduction Organogels or organic self-assemble nanostructures based on π-systems that have inherent electronic properties such as luminescence, charge carrier mobility, and electronic conductivity are extensively used for designing organic electronic devices, such as light emitting diodes (LEDs), field effect transistors (FETs), and photovoltaic devices (PVDs).[1] Among these, organic low molecular weight gelators (LMWGs) with the famous sulfur-rich organic donor molecules, such as tetrathiafulvalene derivatives (TTFs),

Z.-P. Lv, B. Chen, Dr. H.-Y. Wang, Y. Wu, Prof. J.-L. Zuo State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical Engineering Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing 210093, P. R. China E-mail: [email protected]. DOI: 10.1002/smll.201500090 small 2015, DOI: 10.1002/smll.201500090

have received considerable attention because the formed gels usually exhibit redox active response and conducting or semiconducting properties.[2] Most of these LMWGs exhibit high conductivities involve doping of iodine[1g,2g-i] or 7,7,8,8-tetracyanoquinodimethane (TCNQ)[2j,3] as electron acceptors to form charge–transfer (C–T) nanostructures. And those charge–transfer nanostructures with controllable shapes and dimensions become very important and promising in constructing electronic and optoelectronic nanodevices.[4] Although the doping process enhances the electrical properties of those gels, the morphology of the nanostructure will, to some extent, be altered simultaneously. That is to say, enhancing conductivity somehow means sacrifice the structural definiteness of the LMWGs. Luckily, several strategies have been established to construct such structures with variable optical and electronic properties.[5] Among these strategies, using supra-amphiphiles instead of conventional amphiphiles is a relatively novel approach.[6] Due to supra-amphiphiles are assembled by noncovalent interactions such as π–π interactions, hydrogen bonding, charge–transfer interactions, and electrostatic

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Raman scattering (SERS)[14] could be assembled into 1D–3D structures. The dimension of AuNPs assemblies is distinctly affected by the adding amount of MVs.

2. Results and Discussion 2.1. Characterization of C–T Interaction Between TTFs and MVs DMV and HDMV molecules could be assembled into vesicles in aqueous phase due to their amphiphilic nature. Both TEM images (Figure S1a,b, Supporting Information) and DLS (Figure S1c, Supporting Information) analyses showed that vesicles with several hundred nanometers diameter were formed in their solution phase. After the addition of equivalent amount of TTFs, vesicle structure was broken and new structures those using charge–transfer supra-amphiphiles as Scheme 1. Molecular structures of anionic tetrathiafulvalene donors TTFs (TTFA, TTFB, TTFC, building blocks were formed. C–T interand TTFD) and cationic viologen acceptors MVs (MV, DMV, and HDMV). actions between TTFs and viologens were studied by UV–vis absorption spectrosinteractions, architectures fabricated by supra-amphiphiles copy. The formed nanostructures could extincted light in a can be designed to form well-defined nanostructures with large range in UV–vis spectrum due to their size and morcarefully modifying the chemical structures of the building phology can scatter light with certain wavelength. Therefore, blocks.[7] the absorption of C–T bands always overlaps by those strong In this paper, four water-soluble tetrathiafulvalene tetra- light scattering. Herein, the weak but broad C–T bands at carboxylate tetrapotassium salts (TTFA, TTFB, TTFC, and ≈ 600 nm can be clear observed in TTFD-DMV and TTFDTTFD) and two amphiphilic methyl viologens (DMV and HDMV supra-amphiphiles (Figure 1). But still MV can be used to substitute DMV or HDMV HDMV) are engineered to fabricate eight charge–transfer supra-amphiphiles by multiplication principle (Scheme 1, for making similar studies, because TTFs and MV could form details of syntheses and characterizations are in the Sup- ionic complexes that have no scattering effect to UV–vis porting Information). Herein, amphiphilic viologens are not light. Due to relatively low solubility of supra-amphiphiles only acted as an electron acceptor for enhancing conductivity without any external doping,[4c] but also initiate the resultant supra-amphiphiles to assemble into nanoassemblies through hydrophobic interactions. With a rational design of the supra-amphiphiles, the structural influences over the packing fashion and the dimension of self-assembled architectures in water have been realized. Among those multidimensional structures, 1D nanostructures are extremely important due to the constraint of current movement direction thus could be utilized as conductive nanowires.[6b,8] Interestingly, although amphiphiles with multitail topology favor forming bilayer structures such as biological membranes,[6a,9] two supra-amphiphiles contain HDMV in this paper tend to assemble into cylindrical micelles instead of membranes. Additionally, supra-amphiphile driven organic-nanoparticle assembly system has been developed by the advantages of supra-amphiphile noncovalent nature. Gold nanoparticles (AuNPs) which have versatile applications in biomedi- Figure 1. UV–vis spectra of DMV, HDMV, TTFD and its supra-amphiphiles cine,[10] localized surface plasma resonance (LSPR) sensor,[11] with DMV and HDMV. The concentrates of all species are 2.5 × 10−5 M in catalysis,[12] micro-nano photonics[13] and surface-enhanced the main figure and 5 × 10−4 M in the inset figure.

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containing DMV and HDMV molecules, dimethyl viologen (MV) was used as model compound for further studies on the molecular arrangement in the supra-amphiphiles. Spectroscopic titration of TTFs and MV studied by UV–vis spectra revealed that the electron donor–acceptor (D–A) complexes were formed in a very short time after mixing TTFs and MVs (Figure S2, Supporting Information). Moreover, D–A complexes with 1:1 stoichiometry were confirmed by ESI-MS spectrum (Figure S3, Supporting Information), thus supporting the previously reported assumption.[6c] The C–T interactions between TTFs and MVs were also investigated by 1H NMR spectroscopy (Figure 2). MV and TTFs were made into 1 × 10−2 M solution in D2O. As shown in Figure 2a, upon formation of the D–A complex, all the resonances of the protons on MV are shifted upfield suggesting that the whole MV molecule is shielded by TTFA molecule. But the resonances of protons on TTFA shift toward two directions. The resonances of protons close to the molecule center (Ha2) shift up-field due to face-toface stacking. The resonances of protons outside (Ha1) shift

low-field slightly because relatively small MV molecule could not shield those protons at the edge of TTFA molecule and deshielding effect was observed. The effect is more obvious in 1H NMR for TTFB-MV D–A complex (Figure 2b). In TTFB molecule, protons (Hb1) are even more distant from the center that could not stack with π electrons on MV molecule. To the contrary, in the case of TTFD-MV D–A complex, all the resonances of the protons on MV and TTFD are shifted up-field, because a shorter distance of protons (Hd1) to the center made TTFD and MV can shield all the protons by their π electrons (Figure 2d). The D–A complex of TTFC and MV is a special case, that no obvious resonance shift was observed (Figure 2c). Two possible reasons may account for it: (1) TTFC molecule is too small to produce effective stacking as the other three cases; (2) four carboxyl lower the electron density on the tetrathiafulvalene section in TTFC which diminish the shielding effect. However, these resonance shift patterns confirm TTFs and MV molecules are stacking by a face-to-face configuration in aqueous phase.

Figure 2. Partial 1H NMR spectrum of TTFs, MV, and TTFs-MV (D2O, 1 × 10−2 M): a) TTFA-MV, b) TTFB-MV, c) TTFC-MV, and d) TTFD-MV complexes. small 2015, DOI: 10.1002/smll.201500090



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Figure 3. Molecular orientation of TTFD and MV in the crystal structure, viewed along the a) crystallographic a-axis and b) c-axis. c) Side view of the extended p-columnar stacks of TTFD-MV cocrystals bridged by potassium ions. Hydrogen atoms are omitted for clarity.

The D–A complexes structures were also studied by single-crystal X-ray diffraction analysis as more direct evidence. The green needle-like crystals of TTFD-MV complex suitable for crystal structure measurement were grown by evaporating the sample of TTFD and MV (1:1) in water/ DMSO solution (1:1 v/v) at room temperature. The structure of K2(MV)(TTFD)·12H2O can be viewed as a 1D chain of TTFD bridged by potassium ions, and the MV dications are intercalated through π–π and charge–transfer interactions (Figure 3). The interplanar distances of TTFD and MV are about 3.40–3.48 Å, which also indicate charge–transfer interactions between them.[15] Single crystals of TTFB-MV were also obtained by similar method described above. However, they were too small for structure determination. It should have the same structure as TTFD-MV due to similar molecular structure for TTFB and TTFD. Single crystals of TTFA-MV were also successfully obtained by the method described above as brownish rhomboid sheet-like crystals (Figure S5, Supporting Information).

2.2. Morphology of TTFs-MVs Supra-Amphiphiles Nanoassemblies Since both D–A complexes and supra-amphiphiles show similar C–T bands, it is reasonable to suggest that TTFsDMV and TTFs-HDMV supra-amphiphiles have the same assembling pattern as TTFs-MV complex. In TTFs-DMV or

TTFs-HDMV supra-amphiphiles, TTFs as electron donors combine with positive charged viologen head group in DMV or HDMV forming a new hydrophilic head group. And alkane chains in MVs still play the role of hydrophobic part in the newly formed supra-amphiphiles. It should be noted that the new amphiphilic viologen HDMV is designed and it has two alkane chains just like phospholipid molecule. By this designation, the effects of changing both hydrophilic head groups and hydrophobic tail groups in assembling supramolecular nanoassemblies can be studied. Moreover, due to their distinct properties, various structures among those eight nanoassemblies may be observed. Fortunately, TEM and SEM reveal that eight distinct nanostructures were obtained by simply mixing TTFs with equal amount of DMV or HDMV (Figure 4) in water, suggesting that it is possible to regulate the structures of supramolecular nanoassemblies by both modifying hydrophilic and hydrophobic part of the amphiphilic building blocks. (Note: Nanoassemblies consists of TTFA and DMV hereinafter described as “Nano A–D”. Other nanoassemblies will use the same expressions: such as Nano D–H represents nanoassemblies consist of TTFD and HDMV). In Nano A–D, sheet-like structure with several hundred nanometer dimension was formed (Figure 4a). And Nano A–H exhibited an irregular sheet-like structure that folded in some region which was dark in TEM image (Figure 4e). Nano C–D had a membrane structure with micrometer dimension and sphere structure smaller than one hundred nanometers (Figure 4c). Nano C–H was mainly consisted by vesicles with 200–300 nm diameters (Figure 4g). No expected 1D nanostructure was observed in nanoassemblies containing TTFA or TTFC molecules. More regular nanostructure was observed in nanoassemblies containing TTFB and TTFD molecules. Nano B–D showed a short shutter-like structure with 60–80 nm width and 600–1000 nm length (Figure 4b). No clear substructure was found by high resolution TEM (HRTEM) of stained Nano B–D (Figure S4a, Supporting Information). Only the ektexine of the nanoassemblies was stained by phosphotungstic acid, indicating that these shutter-like structures are probably vesicles enclosed by a lipid bilayer membrane. When substituting DMV by HDMV, Nano B–H changed its morphology obviously. Long bar-like nanostructures

Figure 4. TEM images of a) Nano A–D, b) Nano B–D, c) Nano C–D, d) Nano D–D, e) Nano A–H, f) Nano B–H, g) Nano C–H, and h) Nano D–H. The concentration of TTFs and MVs is 1 × 10−4 M in each case. Insert pictures show SEM images of related samples. The scale bar of insert pictures was 2 µm.



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were observed by both TEM and SEM (Figure 4f). Typical dimensions of these nanobars were 4–5 µm in length and 200–300 nm in width. HRTEM images of stained Nano B–H showed that these nanobars were assembled by thinner nanofibers (Figure S4b, Supporting Information). These nanofibers had a uniform 5.4-nm width and very closed to twice the length of TTFB-HDMV amphiphilic complex. This confirms that these tiny fibers are monolayer micelles assembled by TTFB-HDMV amphiphilic complex in a radial pattern.[6b] Similar results in Nano B–D and Nano B–H were also observed in Nano D–D and Nano D–H. Nano D–D showed a rhomboid sheet-like structure with 2–3 µm through long direction and 1–2 µm through short direction (Figure 4d). HRTEM of stained Nano D–D reveals that these rhomboid sheets are likely constructed layer by layer (Figure S4c, Supporting Information). And SEM also showed the rhomboid sheet had sharp edges and certain thickness of several hundred nanometers suggesting that they could be multilayer membrane composed by TTFD-DMV bilayer sheet. By using HDMV instead of DMV in Nano D–D, the most dramatically change was observed. Nano D–H showed perfect 1D nanofiber structure that possesses very large aspect ratio (Figure 4h). These fibers were typically 10–20 µm in length and 60–90 nm in diameter. And some small fibers could form larger ones with hundreds nanometer diameter by twisting with each other. According to HRTEM image, we suppose those fibers are bundles formed by thin micelles with several nanometer diameters (Figure S4d, Supporting Information).

2.3. Structure Analysis of TTFs-MVs Supra-Amphiphiles Nanoassemblies The significant differences of microstructures in the above nanoassemblies attributes to diverse assemble patterns among their basic building blocks. Although MV was changed into amphiphilic DMV/HDMV in these D–A complexes, the combination forms between TTFs or TTFs and MV head groups of DMV/HDMV remain unchanged. It should be noted that, only supra-amphiphiles containing TTFB or TTFD could assemble into regular nanostructure such as nanorods (Figure 4b,f), nanosheets, (Figure 4d) and nanofibers (Figure 4h). In these nanoassemblies, TTFB or TTFD could form 1D chains through potassium-ion bridges, which are similar to that in TTFB-MV or TTFD-MV crystals (Scheme 2a–d). Those amphiphilic 1D chains are the first order building blocks that assemble into bilayer vesicles (Scheme 2e), cylindrical micelles (Scheme 2f,h) or bilayer lamellar micelles (Scheme 2g) through π–π interactions and hydrophobic forces. In these structures, TTFs molecules and amphiphilic viologen head groups maintain the same stacking pattern as they are in the crystals. This ensure the stability of these micelles because such π–π stacking pattern is energetic favorable. Then these micelles as the secondary building blocks compose nanoassemblies with different morphologies through surface charges on individual micelles as the results in TEM and SEM images (Scheme 2i–l). Using this model, the mechanism for sheet like 2D structures in Nano A–D and Nano A–H can be also illustrated. In its crystal structure, TTFA molecules link each other with a

Scheme 2. 3D modes of the possible structures of a,e,i) Nano B–D, b,f,j) Nano B–H, c,g,k) Nano D–D and d,h,l) Nano D–H. TEM images on the right are selected from corresponding samples. small 2015, DOI: 10.1002/smll.201500090



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planar pattern by potassium-ion bridges and hydrogen bonds. Due to nonplanar nature of the four benzene rings in TTFA, MV molecules are embedded in the quadrilateral holes of the TTFAs 2D net skeleton rather than the packing mode with TTF moieties as in TTFD-MV crystals (Figure S5, Supporting Information). It is reasonable to assume the linkage pattern of TTFA molecules remain the same in Nano A–D and Nano A–H. The first order building block in Nano A–D and Nano A–H would be 2D plane instead of 1D chain in nanoassemblies containing TTFB and TTFD (Scheme S1a,b, Supporting Information). Those 2D planes assemble into bilayer lamellar micelles (Scheme S1c,d, Supporting Information) which are the secondary building blocks of those sheetlike nanoassemblies (Scheme S1e,f, Supporting Information). As shown in TEM, Nano A–H had some self-fold regions in its sheet structure. It could be ascribed that bilayer lamellar micelles containing HDMV molecules are not as smooth as those containing DMV molecules due to the steric hindrance resulted from the second alkane chain of HDMV. It should be also noted that both Nano B–H and Nano D–H were assembled by cylindrical micelles, but their morphologies differ from each other due to different micelle lengths and assemble patterns. It is obvious that nanoassemblies containing HDMV tend to form longer nanostructures. Some reasonable but empirical explanations are presented based on 3D modes and experimental facts. From the perspective of thermodynamics, forming longer cylindrical micelles from small molecules is an exothermal but entropy reducing process. Therefore, there is a competition between enthalpy and entropy due to Gibbs free energy formula ΔG = ΔH-TΔS, and the micelles length ceases to increase while ΔG = 0. For this reason, there are two approaches to increase the length of cylindrical micelles, increasing heat releasing or decreasing entropy reducing while assembling. As Scheme 2 shown, the assembling pattern of Nano B–H and Nano D–H secondary building blocks are almost the same. Hence, we

believe there is no obvious difference in the entropy reducing among these processes. But enthalpy part is easier to modify by increasing thermal stability of the forming micelles. This means that thermal stable cylindrical micelles could increase the ΔH changing in the assembling process and then generate longer structures. For more clear illustration, we can divide the cylindrical micelles into two parts: the outside one is hydrophilic part constructed by TTFs molecules and head groups of amphiphilic viologens, the inside one is hydrophobic part constructed by alkane chains of amphiphilic viologens. Comparing the structure of Nano B–H (Scheme 3a) with Nano D–H (Scheme 3b), the hydrophobic part of Nano D–H was more compact than that of Nano B–H due to the hydrophilic part is shortened in axis direction. Thus, the alkane chains of HDMV molecules became closer to each other and harder to enclose in Nano D–H (the green region in Scheme 3). Therefore, the cylindrical structure of Nano D–H is more stable than that of Nano B–H, leading to a longer 1D structure of Nano D–H. To sum up, the decrease of the length of hydrophilic part and increase of the density of hydrophobic part can be favorable in forming longer 1D nanostructure. However, Nano C–D and Nano C–H had no 1D nanostructure although TTFC molecule was the smallest among four TTFs molecules we studied. At least two possible reasons are accountable for it: First, D–A complex of TTFC and MV is not strong enough as discussed in above NMR studies. Most importantly, TTFC molecules are too small to cap amphiphilic viologen head groups and could not form 1D chain effectively. Therefore, TTFC and head group of amphiphilic viologen would arrange without special direction on the hydrophilic surface. In this situation, similar to nanoassemblies formed by pure DMV or HDMV, Nano C–D, and Nano C–H tend to form spherical vesicles instead of cylindrical micelles.

Scheme 3. An illustration of structural difference of a) Nano B–H and b) Nano D–H.



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from 2.2 ± 0.7 nm in Hybrid A (Figure 5a) to 2.7 ± 0.7 nm in Hybrid B, and 2.7 ± 0.9 nm in Hybrid C (Figure 5b,c).[19] TEM images revealed AuNPs in Hybrid B and Hybrid C, mainly arranged in a 2D pattern. The features in UV–vis spectra of the two samples remained unchanged even after 1 month at room temperature, confirming that no further aggregation or coagulation in the assemblies. The increasing amounts of HDMV trigger the assembling of AuNPs themselves. Subsequently, larger AuNPs with more than 50 nm diameter were formed in Hybrid D and Hybrid E (Figure 5d,e). Those larger AuNPs were not stable, thus coagulated after several hours. These are the 3D assemblies of TTFBmodified AuNPs induced by HDMV.[20] The red shift of LSPR peaks from Hybrid A to Hybrid E also revealed the aggregation of AuNPs (Figure 5f). Without the protection of TTFB molecules on the AuNPs surface, control sample Hybrid A′ was easily forming larger particles with 10.2 ± 4.5 nm in diameters which were much bigger than particles in Hybrid A (Figure S6a, Supporting Information). LSPR absorption at 508 nm was observed in UV–vis spectrum of Hybrid A′ (Figure S6b, Figure 5. TEM images of 2 mL TTFB-modified AuNPs mixed with a) 0 µL, b) 20 µL, c) 40 µL, d) Supporting Information). In the control 80 µL, and e) 200 µL HDMV (1 × 10−3 M). f) UV–vis spectrum of Hybrid A–Hybrid E. experiment, Hybrid B′ to Hybrid E′ coagulated almost immediately after adding 2.4. Supra-Amphiphile-Driven Organic-AuNPs Assembly System HDMV solutions (Figure S6b, Supporting Information). This illustrates that without the protection of TTFB on the colloid Base on previous studies, focusing on coinage metal nano- surface, a slightly change of ion species in the solution would materials and conductive TTF gels, introducing AuNPs into disequilibrate surface electric charge of these particles and above supra-amphiphile assembling system has at least two subsequently trigger coagulation. Therefore, both TTFB and advantages. One of the advantages is that synthetic organic HDMV are indispensible for our supra-amphiphile driven systems can control the morphologies and assemble patterns organic-AuNPs assembly system. Interestingly, worm-like assemblies of AuNPs with of AuNPs.[16] Most of AuNPs applications involve the nearfield optical properties of AuNPs with various morphologies 10–20 µm length were found in Hybrid C (Figure 6a). The and assemble patterns. Second, the conductivity of gold nanoparticles doped TTFs xerogel could be dramatically increased to metallic level although only 1 wt% AuNPs were doped.[17] In the study of supra-amphiphile-driven organic-AuNPs assembly system, TTFB-modified AuNPs were first synthesized and then mixed with different amount of HDMV. TTFB could interact with AuNPs surfaces through two paths: (1) TTF moieties donor electrons to AuNPs surfaces;[18] (2) The carboxyl groups in TTFB form coordinate bonds with Au atoms on AuNPs surfaces. The coulomb repulsion generated by carboxyl groups prevents AuNPs from coagulation. Hybrid A to Hybrid E were characterized by TEM (Figure 5a–e) and UV–vis absorption spectra (Figure 5f). A clearly assemble process was observed by TEM images with the increasing amount of HDMV. We believe this assembling Figure 6. TEM images of worm-like assemblies of AuNPs in Hybrid C. was mainly activated by supramolecular interactions between a) Full view of the worm-like assembly. b) Detail view of the rectangular TTFB on AuNPs surface and HDMV. First, AuNPs aggre- region in Figure 7a. c) HRTEM image of AuNPs assemble on the assembly gated but the diameters of those particles changed slightly surface. small 2015, DOI: 10.1002/smll.201500090



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particles’ diameter herein was 6.5 ± 1.3 nm, which was larger than those not assembled into worm-like assemblies (Figure 6b). HRTEM imagine of AuNPs on assembly surface (Figure 6c) showed that the interplanar distance between those crystalline plan was 0.235 nm, relating to the (111) planes of face-centered cubic Au.[21] The worm-like assemblies are presumably formed by AuNPs conjugate to the tubular arranged junction points in cylinder micelles assembled by TTFB-HDMV supra-amphiphiles.[16a]

3. Conclusion Four water soluble tetrathiafulvalene tetracarboxylate tetrapotassium salts and two amphiphilic methyl viologen were synthesized. With multiply principle, nanoassemblies composed by eight supra-amphiphiles were successfully formed. The interactions and assemble pattern of those nanoassemblies have been investigated and elucidated with the help of 1H NMR, ESI-MS, TEM, SEM, and X-ray structure analyses. Importantly, the relationship between the nanoassembly structures and the crystal structures has been clarified. The linkage patterns of TTFs molecules in TTF-MV crystals determine those patterns in the hydrophilic parts of the nanoassemblies and eventually affect their dimensions and morphologies. The change of the structure of hydrophobic part could also have dramatic impact on nanoassembly morphologies. These results indicate that not only 1D or 2D charge–transfer nanoassemblies can be prepared by selecting the water soluble part in supra-amphiphiles, but also their structures and dimensions can be modified by designing the hydrophobic part. Moreover, hybridization of organic charge–transfer nanoassemblies and AuNPs could give 1D–3D structures which makes them potential useful for the transport of electrical charges and new type of optoelectronic nanodevices.

4. Experimental Section Materials: HAuCl4 and NaBH4 were purchased from Sinopharm Chemical Reagent Co. All the chemicals involved in our experiments were of analytical grade and used as received. The ultrapure water (18.2 M Ω cm, 25 °C) was produced by Mill Q system. Other solvents were dried by standard methods. Synthetic procedures for TTFs and MVs are described in the Supporting Information. Synthesis of AuNPs: TTFB modified AuNPs were synthesized by reducing HAuCl4 with NaBH4 in the presence of TTFB according to previous method.[20] In a typical synthesis, 165 µL of HAuCl4 solution (2.43 × 10−2 M) was diluted to 20 mL and 75 µL of TTFB solution (4 × 10−3 M) was added. After cooling to 0 °C, 200 µL of NaBH4 (0.1 M) was added with vigorous stirring. In control experiments, AuNPs were synthesized in the absence of TTFB, under otherwise identical experimental conditions. Supra-Amphiphile Assembly of TTFB-Modiﬁed AuNPs: To assemble TTFB-modified AuNPs with TTFB-HDMV supra-amphiphile, an aqueous solution of TTFB-modified AuNPs (2 mL, [TTFB]/ [HAuCl4] = 0.075) was mixed with different volumes of HDMV (1 × 10−3 M): 0, 20, 40, 80, and 200 µL, respectively. And the above five samples refer as Hybrid A, B, C, D, and E throughout the


paper, respectively. The control samples underwent the same process as TTFB-modified AuNPs (refer as Hybrid A′, B′, C′, D′, and E′ throughout the paper, respectively). Instruments and Measurements: TEM images were performed on JEOL, JEM 2100 microscope operated at 200 kV. Samples were prepared by dropping an aqueous suspension of particles onto a carbon-coated copper grid followed by drying at room temperature. For HRTEM imagines , some samples were negatively stained with phosphotungstic acid solution. SEM images were performed on Hitachi, S-4800 microscope by drop casting the aqueous solution on silica substrate followed by drying at room temperature and was operated with an accelerating voltage of 10 kV. Electronic absorption spectra were recorded on a Shimadzu, UV 2550 UV–vis Spectrometer. UV–vis spectra were recorded in 10 mm path length cuvette. The crystal structure of TTFA-MV was determined with a Siemens (Bruker) SMART CCD diffractometer using monochromated Cu Kα radiation (λ = 1.54178 Å) at 296 K. The crystal structure of TTFD-MV was determined with a Siemens (Bruker) SMART CCD diffractometer using monochromated Mo Kα radiation (λ = 0.71073 Å) at 296 K. The cell parameters were retrieved using SMART software and refined using SAINT[22] for all observed reflections. The data was collected using a narrow-frame method with scan widths of 0.30° in ω and an exposure time of 10 s per frame. The highly redundant data sets were reduced using SAINT[22] and corrected both for Lorentz and polarization effects. The absorption corrections were applied using SADABS[23] supplied by Bruker. The structures were solved by direct methods using the program SHELXL-97.[24] The positions of metal atoms and their first coordination spheres were located from direct methods E-maps. The other nonhydrogen atoms were found in alternating difference Fourier syntheses and least-squares refinement cycles and, during the final cycles, refined anisotropically. Hydrogen atoms were placed in calculated positions and refined as riding atoms with a uniform value of Uiso. CCDC reference numbers are 1042604 for TTFA-MV and 1042605 for TTFD-MV. 1H-NMR spectra were performed on a Bruker AVANCE DRX-500 NMR spectrometer. ESI-MS spectra were recorded on a Thermo Fisher LCQ Fleet apparatus. Hydrodynamic size distributions of DMV and HDMV vesicles in water were determined by DLS using a Brookhaven 90 Plus particle size analyzer.

Supporting Information Supporting Information is available from the Wiley Online Library or from the author.

Acknowledgements This work was supported by the Major State Basic Research Development Program (Grant Nos. 2011CB808704 and 2013CB922101), the National Natural Science Foundation of China (Grant Nos. 51173075 and 91122019), and the Natural Science Foundation of Jiangsu Province (Grant No. K20130054).

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Received: January 12, 2015 Revised: February 24, 2015 Published online:


9

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Protein-induced supramolecular disassembly of amphiphilic polypeptide nanoassemblies.

Supramolecular Amphiphiles Based on Host-Guest Molecular Recognition Motifs.

Polymeric supra-amphiphiles based on terminal group electrostatic interactions: fabrication of micelles with modifiable surfaces.

Self-assembly of pyridinium-tailored anthracene amphiphiles into supramolecular hydrogels.

Hierarchical self-assembly of supramolecular helical fibres from amphiphilic C3-symmetrical functional tris(tetrathiafulvalenes).

Self-assembly of natural and synthetic drug amphiphiles into discrete supramolecular nanostructures.

Supra-amphiphiles: a new bridge between colloidal science and supramolecular chemistry.

Trifluoromethyl-substituted tetrathiafulvalenes.

Nanoassemblies driven by cyclodextrin-based inclusion complexation.

Pillar[5]- and pillar[6]arene-based supramolecular assemblies built by using their cavity-size-dependent host-guest interactions.

Effect of Amide Hydrogen Bonding Interaction on Supramolecular Self-Assembly of Naphthalene Diimide Amphiphiles with Aggregation Induced Emission.

Abducens palsy after lumbar myelography with watersoluble contrast media.

Cardiovascular reactions to myelography with watersoluble contrast media.

Modifiable and non-modifiable factors associated with employment outcomes following spinal cord injury: A systematic review.

"Squalenoylcurcumin" nanoassemblies as water-dispersible drug candidates with antileishmanial activity.

Programmed hydrolysis of nanoassemblies by electrostatic interaction-mediated enzymatic-degradation.

Efficient intravesical therapy of bladder cancer with cationic doxorubicin nanoassemblies.

Whitening Effect of Watersoluble Royal Jelly from South Korea.

Inhibition of protein kinase C by cationic amphiphiles.

Hydrogels formed by enantioselective self-assembly of histidine-derived amphiphiles with tartaric acid.

Toroidal structures from brush amphiphiles.

Built environment and obesity by urbanicity in the U.S.

GNeosomes: Highly Lysosomotropic Nanoassemblies for Lysosomal Delivery.