Complementary functional/interactional groups

Since the first report of the nonequivalence phenomenon, approximately 40 chiral substances have been reported to induce enantiomeric nonequivalence in the NMR spectra of a host of solutes. These CSAs are encountered in subsequent discussions. Two qualities considered to be essential in the design of the first reported experiment (3) are evident in nearly all CSA-solute combinations. In all cases, the CSA and the solute have the common feature of complementary functionality, which permits their interaction. Both are in general hydrogen bond donors or acceptors the CSAs are acids, amines, alcohols, sulfoxides, or cyclic compounds such as cyclodextiins, crown ethers, or peptides, which attractively interact with appropriate enantiomeric solutes, engendering different spatial environments for their nuclei. In nearly every case the CSA contains a group of high diamagnetic anisotropy near its asymmetric center, a feature... 

Abstract The immobilization of nucleic acids onto substrates in array fabrication is a complex process involving three major steps (i) the chemical modification of the arrayed material in such a fashion that it can interact with complementary functionalities present on the substrate to form a stable bond (ii) the coating of the support surface with adequate fimctional groups to allow specific binding and prevent nonspecific adsorption of the material to be arrayed and (iii) the use of a delivery system that brings small quantities of the arrayed material to specific positions on the surface. 

Figure 6.1 General schematic representation of pol3mier-mediated assembly of nanoparticles (a) functionalization of nanoparticles through place-exchange method, (b) incorporation of complementary functional group to pol3miers, and (c) self-assembly of nanoparticles through electrostatic or hydrogen bonding interactions.

Next, complementary functional groups capable of energetically favorable intermolec-ular interactions with the receptor-based functional groups are selected. These complementary functional groups will ultimately form part of the dmg that is being designed... 

This dynamic process is commonly known as constitutional dynamic chemistry (CDC). While the concept of dynamic covalent chemistry defines systems in which the molecular (or supramolecular) reorganization proceeds via reversible covalent bond formation/breakage, dynamic systems based on noncovalent linkage exchanges define the concept of dynamic noncovalent chemistry. Dynamic combinatorial chemistry (DCC) can be defined as a direct application of CDC where libraries of complementary functional groups and/or complementary interactional groups interexchange via chemical (i.e., covalent) reactions or physical (i.e., noncovalent) interactions. 

In addition to increasing charge density at the carbonyls, reduction of flavin to the anion radical converts the electron-deficient aromatic framework of Flox into the electron-rich Fkad- In the FIqx state, the positive electrostatic potential of the atoms on the central ring allows Flox to form favorable 7r-stacking interactions with electron-rich aromatic systems and complementary electrostatic interactions with electron-rich functional groups. Fkad v in contrast, possesses negative electrostatic... 

In addition to enzymes, biological oxidations require substances known as coenzymes. Coenzymes are organic molecules that, in concert with an enzyme, act on a substrate to bring about chemical change. Most of the substances that we call vitamins are coenzymes. The coenzyme contains a functional group that is complementary to a functional group of the substrate the enzyme catalyzes the interaction of these mutually complementary functional groups. If ethanol is oxidized, some other substance must be reduced. This other substance is the oxidized form of the coenzyme nicotinamide adenine dinucleotide (NAD). Chemists and biochemists abbreviate the oxidized form of this... 

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