The C-N coupling reaction of pendant naphthyl group of palladium(II) complexes of 1-alkyl-2-(naphthyl-beta-azo)imidazoles. Structural characterization, spectral and redox properties, and correlation with DFT computed data

摘要

The reaction of Pd(beta-NaiR)Cl-2 (2) [beta-NaiR (1) = 1-alkyl-2-(naphthyl-beta-azo)imidazoles)] with ArNH2 in MeCN has yielded a C-N coupled product chloro[1-alkyl-2-{(7-imidoaryl)naphthyl-beta-azo}imidazole-N, N',N '']palladium(II), Pd(beta-NaiR-N-Ar)Cl (3-5) and coupling takes place at ortho-C-H position of pendant naphthyl group. The structural confirmation has been achieved by single crystal X-ray structure determination of the representative complexes, Pd(beta-NaiEt)Cl-2 (2b) and Pd(beta-NaiEt-N-C6H4-Cl-p)Cl (5b). The electronic spectra of the products, 3-5, exhibit characteristic transition within 600-900 nm those are absent in Pd(beta-NaiR)Cl-2 (2). Cyclic voltammogram shows one oxidative response and two ligand reductions. The products are emissive. The excited state decays via radiative and non-radiative biexponential routes. The electronic structure, spectra and redox properties are explained by DFT computation.