Theoretical studies on structures and spectroscopic properties of 10-hydroxybenzo[h]quinoline zinc(II) and its derivatives substituted by cyano-groups

The geometric structures of 10-hydroxybenzo[h]quinoline zinc [Zn(BQ)2] complex and its derivatives substituted by cyano-groups in the ground state and the lowest singlet excited state were optimized by B3LYP and ab initio CIS methods at LanL2DZ level, respectively. The absorption and emission spectra of these complexes were investigated by the time-dependent density functional theory (TD-DFT) level with PCM model on the basis of the optimized ground and excited states geometries, respectively. The calculated lowest-lying absorptions of all complexes were attributed to ILCT transitions mainly. The calculated emissions of complexes can be described as originated from an excited state with ILCT character mainly. The calculated results showed that the absorption and emission maximums could be tuned by changing the site of the substitutions. The Zn(BQ)2 and its derivatives substituted by cyano-groups were potential electroluminescent materials with blue, green and yellow light emission.