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Theoretical Investigation of the Effect of N Substitution in C ^ N and N ^ N Heteroaromatic Ligands on the Photophysical Properties of Two Series of Iridium(III) Carbene Complexes
Author(s) -
Shang Xiaohong,
Han Deming,
Zhang Huiying,
Zhou Ling,
Zhang Gang
Publication year - 2016
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201501363
Subject(s) - chemistry , iridium , excited state , time dependent density functional theory , steric effects , carbene , density functional theory , atomic orbital , molecular orbital , photochemistry , transition metal , crystallography , computational chemistry , atomic physics , electron , stereochemistry , molecule , physics , organic chemistry , quantum mechanics , catalysis , biochemistry
A DFT/TDDFT investigation has been conducted on two series of cyclometalated iridium(III) complexes to shed light on the effects of structure and steric factors on the photophysical properties. The results reveal that the nature of the N substitution can influence the electron density distributions of the frontier molecular orbitals and their energies, resulting in a change in transition character and emission color. The absorption spectra of the complexes are similar to each other, with 2a – 5a and 2b – 5b presenting a slight redshift compared with their parent complexes. Again, on the basis of the calculations, the higher radiative rate constants ( k r ) of 1a – 5a with respect to 1b – 5b can be explained by a larger metal contribution to the excited states (MLCT%) and larger S 0 –S 1 transition electric dipole moments ( µ S 1).