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An Insight of the Results Provided by Color‐Tuning Studies Made on Ir(III) Complexes: A pi‐Neutral CF 3 Group Viewed by Adjusting Energies of pi‐type Molecular Orbitals
Author(s) -
Lin HungSung,
Lu ShouYun,
Huang FuYung,
Wu Yan,
Su WeiLin,
Wang ShaoPin
Publication year - 2015
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201400271
Subject(s) - chemistry , molecular orbital , natural bond orbital , homo/lumo , pi interaction , atomic orbital , crystallography , hyperconjugation , pi bond , non bonding orbital , computational chemistry , molecular orbital diagram , pyridine , stereochemistry , density functional theory , molecular orbital theory , electron , crystal structure , molecule , bond order , bond length , medicinal chemistry , organic chemistry , physics , quantum mechanics
The pi‐nature of a CF 3 group can be understood through analysis of its bond orbitals (BOs) mixed into the pi‐type molecular orbitals of CF 3 ‐substituted Ir(ppy) 2 MDPA + complexes (ppy=2‐phenyl‐pyridine and MDPA=methylated 2,2′‐dipyridyl amine). It has been found that, through this natural bond orbital analysis, the parent’s molecular orbitals (MOs) can be stabilized by χρ * CF BO via negative hyperconjugation and, simultaneously, destabilized by electron lp(F) BO. Since these two competing pi‐effects are virtually counterbalanced as indicated by the vanishing values of crystal orbital overlap populations, the chemical substitution strategy originated from lowering of HOMO by using this electron‐withdrawing CF 3 group has been found effective in color‐tuning to blue region. Based on reduced shielding effect due to de‐ creased χρ‐electron density, the reported position dependent CF 3 ‐substitution effects on pi‐type MOs can also be understood through HOMO/LUMO wavefunction analysis.