Self hydrogen bonding

Equilibrium Constants (K), Enthalpies (AH), and Entropies (AS) of Self-Hydrogen Bonding of Hydroperoxides... 

Among some of the proton-donating polymers listed in Table 5, i.e. CPS, PS(OH), PS(t-OH) and PS(s-OH), CPS differs from the others by its strong ability of self-hydrogen bonding, as can be inferred from the order of magnitude of the PKa and K2 of their monomers in bulk at 25 °C [161], i.e. ... 

Multifunctional low molecular weight compounds also form a liquid-crystalline network that is dynamic and thermally reversible [39, 40]. Self-hydrogen bonding and dimerization of the benzoic acid side chain of polysiloxanes also induce network mesogenic structures [29]. 

The flic presented contains 11 data items. The header lines arc property names as used by CACTVS [64, 65], and arc sufficiently self-descriptive. For example, E NHDONORS is the number of hydrogen bond donor.s, E SM1LES" is the SMILES string representing the structure of sulfamidc, and E LOGP is the logP value (octanol/water partition coefficient) for this substance. 

F, St-Amant A, I Papai and D R Salahub 1992. Gaussian Density Functional Calculations on Hydrogen-Bonded Systems, journal of the American Chemical Society 114 4391-4400. ter J C1974. Quantum Theory of Molecules and Solids Volume 4 The Self-Consistent Field for Molecules and Solids. New York, McGraw-Hill. 

Fig. 31. Supramolecular (hydrogen-bonded) motifs of self-complementary molecules (196).

Fig. 3. (a) Chemical stmcture of a synthetic cycHc peptide composed of an alternating sequence of D- and L-amino acids. The side chains of the amino acids have been chosen such that the peripheral functional groups of the dat rings are hydrophobic and allow insertion into Hpid bilayers, (b) Proposed stmcture of a self-assembled transmembrane pore comprised of hydrogen bonded cycHc peptides. The channel is stabilized by hydrogen bonds between the peptide backbones of the individual molecules. These synthetic pores have been demonstrated to form ion channels in Hpid bilayers (71). 

The following sections contain a review of many of the varied synthetic systems that have been developed to date utilising noncovalent interactions to form assembhes of molecules. These sections are loosely demarcated according to the most important type of noncovalent interactions utilized in conferring supramolecular order (ie, van der Waal s interactions, electrostatic interactions, and hydrogen bonds). For extensive reviews, see References 1,2,4—6,22,46,49,110—112. Finally, the development of self-assembling, self-replicating synthetic systems is noted. 

Simplified models for proteins are being used to predict their stmcture and the folding process. One is the lattice model where proteins are represented as self-avoiding flexible chains on lattices, and the lattice sites are occupied by the different residues (29). When only hydrophobic interactions are considered and the residues are either hydrophobic or hydrophilic, simulations have shown that, as in proteins, the stmctures with optimum energy are compact and few in number. An additional component, hydrogen bonding, has to be invoked to obtain stmctures similar to the secondary stmctures observed in nature (30). 

FIGURE 12.27 The formation of a cruciform structure from a paliudromic sequence within DNA. The self-complementary Inverted repeats can rearrange to form hydrogen-bonded cruciform loops. 

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