Formation Of Supramolecular Polymers Research Articles

Steric Control over Supramolecular Polymer Formation in trans-1,2-Bis(4-pyridyl)ethylene Adducts of Zinc Xanthates: Implications for Luminescence

Steric control over supramolecular aggregation is demonstrated for a series of adducts formed between Zn(S2COR)2 and trans-1,2-bis(4-pyridyl)ethylene, whereby supramolecular zigzag polymers are found when R is small, that is, Et (1) and n-Bu (2), but only bimetallic aggregates could be formed when R = Cy (3). This results in different coordination geometries: four-coordinate N2S2 zinc in 1 and 2, and five-coordinate NS4 zinc in 3, a feature which greatly influences photophysical responses in the solid state. When excited in the UV region, {Zn(S2COEt)2L}∞ (1) and {[Zn(S2COCy)2]2L} (3) produce broad luminescence in the visible region. Five-coordinate 3 produces more broad and intense luminescence than four-coordinate 1. The configuration interaction singles (CIS) and post-Hartree−Fock (HF) calculations for 1 and 3 indicate the A-band excited state is responsible for the observed luminescence which is strongly associated with charge transfer from S and Zn.

Two novel quadruple hydrogen-bonding motifs: the formation of supramolecular polymers, vesicles, and organogels

Two new hydrazide-based quadruple hydrogen-bonding motifs are described. Dipodals based on these two motifs are revealed to form supramolecular polymers, which can further aggregate to form vesicles and/or organogels in hydrocarbons. The quadruple hydrogen-bonding motifs are characterized by the X-ray diffraction and (2D) 1H NMR experiments, while the vesicles and organogels are evidenced by SEM, AFM, TEM, and fluorescent microscopy.

Binuclear Organoplatinum(IV) Complexes with Bridging Xylenediyl Groups: Formation of Supramolecular Polymers through Hydrogen Bonding

Oxidative addition reactions of α,α′-dibromo-o-xylene, -m-xylene, and -p-xylene to two units of [PtMe2(bu2bipy)], bu2bipy = 4,4′-di-t-butyl-2,2′-bipyridine, give the corresponding binuclear organoplatinum(IV) complexes with bridging xylenediyl groups, [C6H4{CH2PtBrMe2(bu2bipy)}2]. Oxidative addition of C6-1,3,5-Me3-2,4,6-(CH2Br)3 to three units of [PtMe2(bu2bipy)] gave the triplatinum(IV) complex [C6-1,3,5-Me3-2,4,6-{CH2PtBrMe2(bu2bipy)}2]. In the sterically congested complexes 1,2-[C6H4{CH2PtBrMe2(bu2bipy)}2] and [C6-1,3,5-Me3-2,4,6-{CH2PtBrMe2(bu2bipy)}2], there is restricted rotation of the xylylplatinum groups. Bromide abstraction from the binuclear bromoplatinum(IV) complexes with AgPF6, followed by the addition of a pyridine ligand with one or two carboxylic acid functional groups, gave binuclear organoplatinum(IV) compounds containing at least two carboxylic acid groups, with the potential to polymerize through intermolecular hydrogen-bonding interaction in the solid state. During crystallization o...

Formation of Supramolecular Polymers and Discrete Dimers of Perylene Bisimide Dyes Based on Melamine−Cyanurates Hydrogen-Bonding Interactions

Melamine-linked perylene bisimide dyes (MPBIs) bearing an ethylene or trimethylene group as linker moieties were synthesized, and their self-aggregation and coaggregation with cyanurates through complementary triple hydrogen bonds have been investigated. UV/vis studies revealed that both the MPBIs self-assemble in nonpolar organic solvent through pi-pi stacking interaction between perylene cores, giving self-aggregates with nearly identical thermal stabilities. Upon addition of 1 equiv of cyanurate components, however, the stabilities of the resulting aggregates were dramatically changed between the two systems, suggesting the formation of different types of hydrogen-bonded supramolecular species. Dynamic light scattering and atomic force microscopic studies revealed that the system featuring ethylene linker moieties generates a discrete dimer of MPBI supported by two cyanurate molecules, whereas the system featuring trimethylene linker moieties affords extended supramolecular polymers hierarchically organizing into nanoscopic fibers. These results demonstrate that it is possible to obtain distinct supramolecular species by just changing the number of carbon atoms at the linker moieties of MPBI components. The present strategy for the fabrication of discrete or polymeric supramolecular assemblies should be applicable to other functional pi-conjugated molecules.

Asymmetrical supramolecular interactions as basis for complex responsive macromolecular architectures

Intrigued by natural responsive systems based on a combination of macromolecules and non-covalent interactions, polymer scientists have mimicked such systems by the formation of supramolecular polymers based on ionic interaction, hydrogen bonding and metal coordination. In recent years, the focus has shifted from rather simple non-directional and self-complementary interactions to the use of asymmetrical directional supramolecular interactions that allow the formation of complex responsive macromolecular architectures such as block copolymers, star-shaped polymers and graft copolymers. This feature article covers these recent developments on the use of asymmetrical supramolecular interactions in polymer science. Special attention is given to the formation of complex macromolecular architectures using directional supramolecular interactions. In addition, the responsiveness of the resulting macromolecular systems is discussed based on the assembly and/or disassembly that can be triggered by changes in external conditions.

Polymeric Ordering by H-bonds. Mimicking Nature by Smart Building Blocks

Functional macromolecules can self assemble into regular structures yielding biological structures. The present review assembles recent literature on the formation of supramolecular polymers via hydrogen bonding forces and functional aggregates derived therefrom.

Supramolecular Polymer Formation by Metal−Ligand Complexation: Monte Carlo Simulations and Analytical Modeling

Equilibrium metal-ligand complexation leading to formation of linear or ringlike supramolecular polymers is studied by means of Monte Carlo (MC) simulations and theoretical analysis. We found that in most of the cases high-molecular-weight polymers are formed over a rather narrow composition range (near the 2:1 ligand-metal ratio). Besides the imbalance in the number of metals and ligands, the molecular weight decrease in the metal-rich area is caused by an increase in 1:1 ligand-metal complex formation. The results of simulations and theoretical modeling show that the fraction of 1:1 complexes considerably decreases for metal-ligand pairs with a high cooperativity of complexation. On the basis of our analytical model, we suggest a simple criterion for choosing the metal/ligand pair to achieve high molecular weight complexes in a broad range of metal-rich compositions. Dilution of a solution of metallosupramolecular polymers is found to decrease the average molecular weight and to enhance ring formation, which otherwise is very limited.

Formation of Supramolecular Polymers Constructed by Cyclodextrins with Cinnamamide

α-Cyclodextrin having cinnamamide at 6- or 3-positions (6-CiNH-α-CD, 3-CiNH-α-CD) and β-cyclodextrin with cinnamamide on 6-position (6-CiNH-β-CD) have been prepared. Supramolecular structures were formed in the solid state or aqueous solutions and characterized by measurements of NMR and vapor pressure osmometry (VPO). The results indicate that 6-CiNH-β-CD formed insoluble supramolecular polymers in the solid state, while 6-CiNH-α-CD and 3-CiNH-α-CD formed supramolecular complexes in aqueous solutions. 6-CiNH-α-CD was found to form a dimer in an aqueous solution. 3-CiNH-α-CD formed intermolecular complexes to give supramolecular polymers. The differences of the position of guest part on cyclodextrins caused to give a variety of supramolecular structures in aqueous solutions.

Formation of Supramolecular Polymers Constructed by Cyclodextrins with Cinnamamide

Formation of Supramolecular Polymers Constructed by Cyclodextrins with Cinnamamide

Chiral Amplification of the Structure and Viscoelasticity of a Supramolecular Polymeric System Consisting of N,N‘,N‘‘-Tris(3,7-Dimethyloctyl)Benzene-1,3,5-Tricarboxamide and n-Decane

The influence of a chiral gelator molecule, N,N‘,N‘‘-tris-(S)-(3,7-dimethyloctyl)benzene-1,3,5-tricarboxamide ((S)DO3B), on the structure in the formation of supramolecular polymers and viscoelasticity was examined in an organogel system consisting of a racemic mixture of the gelator molecule, N,N‘,N‘‘-tris(3,7-dimethyloctyl)benzene-1,3,5-tricarboxamide (DO3B), and n-decane. In the absence of the chiral gelator, equal amounts were observed of the right- and left-handed helicities of the formed columnar supramolecular polymers. Addition of (S)DO3B markedly induced one helicity in excess, due to the Majority Rule effect. Although there are two possibilities, (1) left- and right-handled helices within single supramolecular polymers and (2) mixtures of homochiral supramolecular helical polymers, the viscoelasticity of the system supports the former. Without (S)DO3B, 60% of the amide groups of the gelators formed hydrogen bonding in the system; upon increasing the relative (S)DO3B composition (relative to the ...

Hydrogen‐bonded supramolecular poly(ether ketone)s

AbstractThe preparation of 2,4‐diamino‐1,3,5‐triazine telechelic poly(ether ketone)s (triazine PEKs) and the formation of supramolecular polymers with dodecyl‐(α‐ω)‐bis(5‐methyl‐1,3‐pyrimidine‐2,4‐dione) were investigated. Both structures interacted by complementing hydrogen‐bonding units present at their respective chain ends, this being reminiscent of triple hydrogen bonding in DNA. The preparation of the triazine PEKs started from hydroxyl‐terminated poly(ether ketone)s by a nucleophilic displacement reaction with 2,4‐diamino‐6‐(4‐fluorophenyl)‐1,3,5‐triazine. With this method and molecular weight control via the Carothers equation, a series of triazine PEKs with a complete degree of end‐group functionalization were prepared. The structure of the polymers was proven by 13C NMR spectroscopy and matrix‐assisted laser desorption/ionization spectroscopy. When mixed as a 1:1 complex in solution with dodecyl‐(α‐ω)‐bis(5‐methyl‐1,3‐pyrimidine‐2,4‐dione), short triazine PEKs (molecular weight = 5700 or 10,000) showed a temperature‐dependent association behavior visible via dynamic NMR spectroscopy. Additional proof of the formation of a supramolecular, hydrogen‐bonded network was derived from solid‐state NMR spectroscopy, differential scanning calorimetry, and rheological investigations. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 661–674, 2004

N,N'-disubstituted ureas: influence of substituents on the formation of supramolecular polymers.

Symmetrical N,N'-disubstituted ureas have been synthesized and characterized. Among them, the branched dialkylureas prepared are highly soluble in organic media. Moreover, the solutions obtained are very viscous in heptane, if the branched alkyl groups are not too bulky (i.e. a methyl group on the alpha carbon, or an ethyl group on the beta carbon). Due to the strong, bifurcated hydrogen bonds between the urea moieties, linear supramolecular polymers are formed. The degree of association of these supramolecular polymers has been determined by FTIR spectroscopy.

Formation of Supramolecular Polymers from Homoditopic Molecules Containing Secondary Ammonium Ions and Crown Ether Moieties

As if with a molecular building kit, a linear supramolecular pseudorotaxane polymer was formed with reversible chain extension in solution by self-organization of two complimentary homoditopic molecules with secondary ammonium and dibenzo[24]crown-8 moieties.

Formation of Supramolecular Polymers from Homoditopic Molecules Containing Secondary Ammonium Ions and Crown Ether Moieties

Formation of Supramolecular Polymers from Homoditopic Molecules Containing Secondary Ammonium Ions and Crown Ether Moieties