Molecular electrostatic potential for exploring π-conjugation: a density-functional investigation??

Physical Chemistry Chemical Physics Pub Date: 2011-07-21 DOI: 10.1039/C1CP20071B

Abstract

Molecular electrostatic potentials (MESP) of the most common building blocks of organic π-conjugated systems, viz.ethylene, acetylene, benzene, furan, pyrrole, thiophene and phenylvinylene, are examined at the B3LYP/6-311++G(2d,2p) level. The topography of MESP is employed for mapping the strength of electronic conjugation between these building blocks. When electron-rich molecular regions are connected to each other, the MESP value of the corresponding conjugation critical point (CCP) is able to provide a quantitative measure of the strength of the conjugation. The systems with stronger conjugation are generally seen to possess a larger negative value of CCP and a smaller difference (ΔVCM?CCP) between the MESP values of respective conjugated minimum (CM) and the CCP, in agreement with the experimental as well as other theoretical results. The present MESP topography-based approach thus offers a measure of the quantitative strength of π-conjugation in molecules.

Graphical abstract: Molecular electrostatic potential for exploring π-conjugation: a density-functional investigation
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