Premium
The Pi‐Nature of Methyl Obtained by the Natural Bond Orbital Method: Orbital‐Based Rationalizations of Site‐Dependent Substitution Effects on Fine Color‐Tuning of Luminescence
Author(s) -
Su WeiLin,
Wang ChengChi,
Wang ShaoPin
Publication year - 2012
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.201200354
Subject(s) - homo/lumo , natural bond orbital , chemistry , antibonding molecular orbital , molecular orbital , non bonding orbital , computational chemistry , molecular orbital diagram , photochemistry , crystallography , atomic orbital , stereochemistry , valence bond theory , organic chemistry , molecule , physics , electron , density functional theory , quantum mechanics
Both C‐H bonding and antibonding (σ CH and σ* CH ) of a methyl group would contribute to the highest occupied or lowest unoccupied molecular orbitals (HOMO or LUMO) in methylated derivatives of Ir(ppz) 2 3 iq (ppz = 1‐phenylpyrazole and 3iq = isoquinoline‐3‐carboxylate). This is found by analysis of HOMO (or LUMO) formed by linear combination of bond orbitals using the natural bond orbital (NBO) method. The elevated level of HOMO (or LUMO) uniformly found for each methylated derivative, indicating the σ CH ‐destabilization outweighs the σ* CH ‐stabilization. To broaden the HOMO‐LUMO gap, methylation at a carbon having smaller contribution to HOMO and/or larger contribution to LUMO is suggested.