Supramolecular polymerization

Supramolecular polymers are a relatively new class of polymers in which monomeric repeating units are held together with directional and reversible (noncova-lent) secondary interactions (Lehn, 2000), unlike conventional macromolecular species in which repetition of monomeric units is mainly governed by covalent bonding. A schematic comparison of a covalent polymer and a supramolecular polymer is shown in Fig. 1.3. 

Moldings and sheets transparent and tough used for safety glasses, screens and glazings, electrical and electronics, appliances, compact discs, e.g. Merlon, Baylon, Jiipilon. 

Moldings, coatings, membranes rigid, transparent, self-extinguishing, resistant to heat deformation used for electrical components, molded circuit boards, appliances operating at high temperatures, e.g., Victrex PES. 

Moldings, composites, coatings oulstatiding in heat resistance, flame resistance, chemical resistance and electrical insulation resistance used for electrical components, mechanical parts, e.g., Ryton, Tedur, Fortron. 

High modulus fibers as strong as steel but have one-fifth of weight, ideally suited as tire cord materials and for ballistic vests, e.g., Kevlar, Twaron. 

Moldings, fibers, tirecord poly(hexamethylene adipamide) (Nylon 6,6)e.g., Ultramid A polycaprolactam (nylon-6), e.g., Ultramid B, Akulon, Perlenka, poly(hexamethylene sebacamide) (Nylon-6,10), e.g., Ultramid S, Zytel. 

Textile fibers, film, bottles poly(ethylene terephthalate) (PET) e.g., Terylene, Dacron, Melinex, Mylar. 

Rubbers, foams, coatings e.g., Vulkollan, Adiprene C, Chemigum SL, Desmophen A, Moltopren. 

Elastomers, sealants, fluids, e.g.. Silastic, Silastomer, Silopren. 

---

Barboiu, M. (2004) Supramolecular polymeric macrocyclic receptors-hybrid carrier vs. channel transporters... 

Kato, T. Mizoshita, N. Kanie, K. Hydrogen-bonded liquid crystalline materials Supramolecular polymeric assembly and the induction of dynamic function. Macromol. Rapid Commun. 2001, 22, 797-814. 

SUPRAMOLECULAR POLYMERIZATION OF PEPTIDES AND PEPTIDE DERIVATIVES NANOFIBROUS MATERIALS... 

MS can be used to study several intrinsic physicochemical properties of ILs, for example, the acidity of components of ILs or the determination of wafer miscibilities. Furthermore, MS delivers valuable information about noncovalent interactions, for example, responsible for the formation of quasi-molecular structures [23] formed by three-dimensional supramolecular polymeric networks within the IL. 

Figure 39 represents schematically such a process in the case of two-site (ditopic) complementary components Te 2 and Ts2. The resulting supramolecular polymeric material ((Te 2, T32) may present liquid-crystalline properties if suitable chains are grafted onto the components. One may note that the mixed site species e Tsrepre-... 

Fig. 43. Ternary recognition components for the cross-linking of supramolecular polymeric species [9.149],...

Figure 91. The supramolecular polymeric structure of [Zn(S2CO—i-Bu)2(4,4 -bpy)]00 viewed along the c axis the molecule is centrosymmetric about half of the C—C bonds of the 4,4 -bpy molecules and the other half are disposed about a twofold axis.

The self-catalyzed model is a simplification of the actin polymerization model of Oosawa and Kasai (1962) [and more recent elaborations of it (Niranjan et al., 2003)], and both equilibrium constants K and Kn, and hence the free energies g and ga can in principle be obtained by fitting the theory to assembly experiments. Typical values of g for, for example, actin vary between —10 and —20 kBT and ga between +2 and +3 kBT (Oosawa and Asakura, 1975 Oosawa and Kasai, 1962). For the biomimetic compound oligo(phenylene vinylene) similar to compound 2 shown in Figure 6, dissolved in alkane solvents, similar values were found for g but much larger ones for ga of +8 to +10 kBT, making the supramolecular polymerization of this compound an extremely highly co-operative process (Jonkheijm et al., 2006). 

The assembly models discussed in the preceding sections are presumably the simplest ones that one can set up for co-operative supramolecular polymerization. Their advantage is the relatively small number of adjustable parameters and conceptual simplicity. Disadvantage is the lack of a detailed description of the processes that actually led to the assembly becoming nucleated and that are system specific, that is, that depend on the details of the molecules involved and how precisely they interact. 

Nucleated supramolecular polymerization, on the other hand, is a much more sensitive function of the external conditions. Indeed, a sharp polymerization point can be identified below which almost no material is in the polymerizated state and above which the self-assembled polymers exhibit a strong variation of their mean size with varying concentration, temperature, and so on. Nucleated equilibrium polymerization requires the existence of... 

If the conformational switching is that between high-molecular weight polymeric species, then the structural transition between them can be highly co-operative but the assembly remains by and large isodesmic. So, co-operativity is a required but not a sufficient condition for creating nucleated supramolecular polymerizations. 

Ciferri, A. "Supramolecular polymerizations". Macromol. Rapid Commun. 23, 511 (2002). 

Zhao, D., and Moore, J.S. "Nucleation-elongation a mechanism for cooperative supramolecular polymerization". Org. Biomol. Chem. 1, 3471-3491 (2003). 

Nitrobenzimidazole-2-carboxylate 3-oxides on X-ray diffraction data exist in /V-hydroxy tautomers [190], In the crystal a strong 0-(HN)-N-.,.intermolecular bond gives rise to supramolecular polymeric chains in the lattice. 

With a different design, where chirahty is directly built in the hydrogen bond pattern (Fig. 22), Aida et al. have demonstrated that it is possible to enforce a homochiral supramolecular polymerization [141]. In this case, a mixture of L and D monomers exclusively forms supramolecular chains of polyL and polyD homopolymers instead of copolymers. 

Complexes of ligands with O-donors and two or three N-donors are known. The kinetics of the outer-sphere oxidation of cis-aq uaoxovanad i u m (IV) complexes of [2-(pyridylmethyl)imino]diacet-ate and its derivatives were determined.675 Complexes with Schiff bases have been used to mimic the structure and chemistry of vanadium bromoperoxidase.275 The ligation of an imidazole functionality in the ligand has been found to readily dissociate, and is important to the functional aspects of this complex.275 A variety of five-coordinate complexes with tridentate Schiff base complexes have been prepared, several of which have been found to form supramolecular polymeric structures through association between the V=0 groups in a V=0 V=0 V=0 pattern (140).627... 

This section is divided into three parts. The first part, section A, deals with rodlike polymers formed by the arene—arene interactions. In the second part (B) discotics will be discussed for which unidirectional hydrogen bonding is the driving force for supramolecular polymerization. Finally, section C will deal with supramolecular polymers formed by a combination of arene—arene interactions and hydrogen bonding. 

The intrinsic helicity of the columns formed by bifunctional 50 allows chiral side-chains to control for a preferred handedness (50b). The supramolecular polymeric backbone also accounts for a higher DP with respect to monofunctional 49, as could be observed with SANS and an increased thermostability of the lyotropic mesophase in dodecane. The induction of chirality in the helical columns of 50b by the chiral side is a cooperative process via the backbone the helicity of a racemic mixture of helical columns of achiral 50a is biased when end-capped with monofunctional chiral 49b. 

---