Quantitative relationships between structure

Within the context of this book the quantitative relationships between structure and chemical reactivity are very informative. One of the early postulates of Ingold and his school in the 1930s (review see Ingold, 1969, p. 78) was that the electronic effects of substituents are composed of two main parts a field/inductive component and a mesomeric component. Hammett s work indicated clearly from the beginning that his substituent constants am and crp reflect Ingold s postulate in numerical terms. In particular, many observations indicated that the /7-substituent constant ap is the sum of a field/inductive component 0 and a resonance (mesomeric) component (Jr. 

To sum up, the analytical mode proposed presents a rare instance when a rather simple treatment enables not only qualitative but also quantitative relationships between structure and optical properties to be revealed. 

Hydrophobicity (log P) is related to the desolvation of the ligand, and it is assumed that the desolvation of the ligands going from water to octanol parallels that of going from water to a cleft or pocket of a receptor. Thus, log P may be an important term in establishing quantitative relationships between structure and activity (26). In order to examine the influence of the lipohilic character of the 4-PIOL analogs on the affinity for the GABAa receptor, QSAR analysis was performed (24). 

QUANTITATIVE RELATIONSHIPS BETWEEN STRUCTURE AND METAL-BINDING AFFINITY... 

Evelyne, C., Andre, C., Georges, T., Michel, T. (1992) Quantitative relationships between structure and penetration of phenylurea herbicides through isolated plant cuticles. Chemosphere 24(2), 189-200. 

The structure of a chemical is responsible for the presence and magnitude of its properties. The properties can be energy levels and their derivatives, as well as physicochemical, or biological, properties. To avoid discrimination between the different properties (which are the subject of detailed consideration in Chapters 3, 4, and 6) in the context of quantitative relationships between structural descriptors (i.e., topological indices [TIs]) and various properties, we will use the broader abbreviation QSPR (Quantitative Structure-Property Relationship). 

Quantitative relationships between structures, environmental temperatures and properties. 

Johnson BA, Leon M. Modular representations of odorants in the glomerular layer of the rat olfactory bulb and the effects of stimulus concentration. J. Comp. Neurol. 2000 422 496-509. Laing DG, Legha PK, Jinks AL, Hutchinson 1. Relationship between molecular structure, concentration and odor qualities of oxygenated aliphatic molecules. Chem. Senses 2003 28 57-69. Rossiter K. Quantitative relationships between structure and the fruity odor of esters. Perfumer Flavorist 1996 21 33-36, 38-40, 42-44, 46. 

It appears that the basic mechanisms involved in polymerization and, in particular, in photopolymerization of diacetylenes are understood. Nevertheless, to date it is not possible to design a diacetylene monomer on the basis of desired reaction behavior and/or product properties. To this end more quantitative information on the reaction kinetics of diacetylenes including quantum-mechanical aspects is needed which could form the basis for developing a quantitative relationship between structure and reactivity. 

Quantitative relationship of chemical structure to physical properties in network polymers has received considerably less attention and study than in the case of thermoplastics. However, in recent years, progress has been made towards elucidation of the quantitative relationships between structure and properties. We have chosen to illustrate the quantitative effect of structural factors on physical properties in four representative areas glass transition temperature, modulus of elasticity, mechanical damping, solvent resistance. 

Chaumat, E., Charnel, A., Taillandier, G. and Tissut, M. (1992). Quantitative Relationships Between Structure and Penetration of Phenylurea Herbicides Through Isolated Plant Cuticles. Chemosphere, 24,189-200. 

Pavlikova, M., Lacko, I., Devinsky, F. and Mlynarcik, D. (1995). Quantitative Relationships Between Structure, Aggregation Properties and Antimicrobial Activity of Quaternary Ammonium Bolaamphiphiles. Collect.Czech.Chem.Comm., 60,1213-1228. 

Hinderling PH, Schmidlin O and Seydel JK, Quantitative relationships between structure and pharmacokinetics of beta-adrenoceptor blocking agents in man, J. Pharmacokin. Biopharm., 12, 263-287 (1984) Ref. Tempelton R, May Baker Ltd., Dagenham, England. Personal communication. 

Silipo C and Vittoria A, Relationships between octanol-water partition data, chromatographic indices and their dependence on pH in a set of beta-adrenoceptor blocking agents, Farmaco, 45, 647-663 (1990). See also Hinderling PH, Schmidlin O and Seydel JK, Quantitative relationships between structure and pharmacokinetics of beta-adrenoceptor blocking agents in man, J. Pharmacokin. Biopharm., 12, 263-287 (1984). Taylor EA, Jefferson D, Carroll JD and Turner P, Cerebrospinal fluid concentrations of propranolol, pindolol, and atenolol in man Evidence for central actions of beta-adrenoceptor antagonists, Br. J. Clin. Pharmacol, 12, 549-559 (1981). NB See Pindolol for furdter details. 

II. Quantitative relationships between structure and enantio-selective retention in high performance liquid affinity chromatography. Mol. Pharmacol. 1992, 42, 512-517. 

In order to get quantitative relationships between structures and their properties, one needs to And suitable numerical characterizations of structures. Numerical characterizations of the structure can then generate numerical descriptors of structures to be used for construction of structure-property correlations. Suitable structure descriptors could be tested to see if they correlate with molecular bioactivity in modeling effects and responses of such substances on living tissue or organisms. In this way, one can identify bioactive natural products or synthesized compounds, which can show novel therapeutic activities and be able to protect against diseases or combat diseases or harmful chemicals that have toxic or mutagenic effects, etc. 

---