Stereochemical complementarity

Packing or stereochemical complementarity (Richards and Lim, 1993) is an important source of the new bonding interactions, required to stabilize unique native stmcture. 

During the mineralization process of calcium carbonate induced by a 6-sheet template made of a phospholipid-peptide conjugate, it was also shown that the orientations of the crystals were related to geometrical matching lattice and stereochemical complementarity between the functional groups of the template and the positions of the ions in the nucleation plane. However, the nucleation of different crystal faces can be achieved depending on the ability of the template to adapt to the structure of the inorganic phase, without the need for an epitaxial relation between the two components. ... 

The surface complementarity between the quantum activated complex and the catalytic surrounding media is the main idea of the present theory. The oscillating stereochemical control of the synthesis of thermoplastic elastomeric polypropylene recently reported by Coates and Waymouth [208] can be easily interpreted in terms of catalyst changing surface complementarity. Hill and Zhang have discovered a molecular catalyst that experiences a kinetic and thermodynamic drive for its own reassembly and repair under conditions of catalysis [209]. This is basically what an enzyme does when moving from the apo-structure towards the catalytically apt conformation. 

Intramolecular cyclization of tethered phenyl ketones (58 X = Br, SiMe3) show contrasting stereochemical outcomes for indium catalysis of the alkyl bromides and fluoride ion-induced reaction of the allylsilanes. The reactions thus allow complementarity in product diastereoselectivity, and the difference appears to be related to an... 

The combination of the nonpalindromic nature of the peptide backbone and the chirality of the a-carbons in the amino acids comprising the oligomeric structure provides a unique opportunity for vast stereochemical and topochemical diversities. Earlier studies explored the interesting structural relationship between all-L-, retro-all-L-peptides, and their enantiomers (see reviews[1 3]). Schematically, a high degree of topochemical complementarity is obtained between parent cyclic peptides and their retro-inverso analogues.11 ... 

Complexation could occur in many different ways, but for the intimate com-plexation required for catalysis, the enzyme must have, or must be able to assume, a shape complementary to that of the substrate. Originally, it was believed that the substrate fitted the enzyme somewhat like a key in a lock this concept has been modified in recent years to the induced-fit theory, whereby the enzyme can adapt to fit the substrate by undergoing conformational changes (Figure 25-18), Alternatively, the substrate may be similarly induced to fit the enzyme. The complementarity is three-dimensional, an important factor in determining the specificity of enzymes to the structure and stereochemical configuration of the substrates. 

Glycals serve as activated sugars because of the inherent reactivity of the endocyclic enol ether. Consequently, they have been extremely useful substrates in their complementarity to native activated sugars. Additionally, they have been used to demonstrate versatility not directly available from other sugar derivatives. In a good example of the utility of allylsilanes and silylacetylenes in C-glycoside chemistry, Ichikawa et al. [91] demonstrated a preference for the a anomer in all cases. The results, shown in Scheme 7.17, included a demonstration that a characteristic nOe can be used to confirm the stereochemical outcome of the reaction with hw-trimethylsilylacetylene. 

Two tridentate ligands L64 are coordinated to manganese(II) meridionally. The coordination polyhedron around the central atom is a compressed octahedron with two short Mn-N distances of 18.9(1) nm trans to each other, and with four longer equatorial Mn-N bonds of average length 19.85 nm [90]. The above oxidation reaction is thought to be driven by the tendency to achieve maximal complementarity between stereochemical demands of the matrix, and the possibilities of the ligand product (conformational and electronic) to satisfy them. 

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