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Theoretical Investigations on the Geometric and Electronic Structures of Phenylene‐Acetylene Macrocycles
Author(s) -
Li Yanwei,
Zhao Jianwei,
Yin Xing,
Yin Geping
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600416
Subject(s) - ab initio , phenylene , acetylene , computational chemistry , electronic structure , chemistry , conjugated system , planar , ring (chemistry) , ab initio quantum chemistry methods , homo/lumo , molecule , molecular orbital , polyacetylene , crystallography , chemical physics , materials science , polymer , organic chemistry , computer graphics (images) , computer science
The geometric and electronic structures of a series of conjugated macrocycles (phenylene‐acetylene macrocycles, PAMs) have been studied theoretically with ab initio and semiempirical molecular orbital methods. The ab initio calculations at the HF/6‐31G* level demonstrate that the model molecules may have a planar conformation. Bigger macrocycles, for example, 7PAM, 8PAM, and 9PAM, result in several energy minima. The boatlike conformation is the most energetically favored form. Based on the conformational analysis, a novel method for analyzing the ring‐strain energy was proposed and used. In view of their potential applications as electronic materials, the electronic structures of a series of PAMs are also investigated. The LUMO–HOMO gaps of the planar PAMs show an odd–even difference behavior. In addition, the HOMOs of the planar species 3PAM, 5PAM, 7PAM, and 9PAM are doubly degenerated.