An Insight of the Results Provided by Color‐Tuning Studies Made on Ir(III) Complexes: A pi‐Neutral CF3 Group Viewed by Adjusting Energies of pi‐type Molecular Orbitals

• DOI: 10.1002/jccs.201400271
• Publication Date: 2015-11-07T21:41:26Z
• Authors: Hung‐Sung Lin; Shou‐Yun Lu; Fu‐Yung Huang; Yan Wu; Wei‐Lin Su; Shao‐Pin Wang
• Keywords: Natural bond orbital; HOMO/LUMO; Pi interaction; Hyperconjugation; Pi bond; Non-bonding orbital; Molecular orbital diagram

Abstract The pi‐nature of a CF 3 group can be understood through analysis its bond orbitals (BOs) mixed into the pi‐type molecular ‐substituted Ir(ppy) 2 MDPA + complexes (ppy=2‐phenyl‐pyridine and MDPA=methylated 2,2′‐dipyridyl amine). It has been found that, this natural orbital analysis, parent’s (MOs) stabilized by χρ * BO via negative hyperconjugation and, simultaneously, destabilized electron lp(F) BO. Since these two competing pi‐effects are virtually counterbalanced as indicated vanishing values crystal overlap populations, chemical substitution strategy originated from lowering HOMO using electron‐withdrawing effective in color‐tuning to blue region. Based on reduced shielding effect due de‐ creased χρ‐electron density, reported position dependent ‐substitution effects MOs also HOMO/LUMO wavefunction analysis.