Carbazolyl-bis(triazole) and Carbazolyl-bis(tetrazole) Complexes of Palladium(II) and Platinum(II)

The synthesis of several carbazole-bis(triazole) (CzTrR) and carbazole-bis(tetrazole) (CzTR) ligands (5a–d 6a–d, respectively, where R=Me (a), i–Pr (b), Bz (c) CH2-2,4,6-C6H2Me3 (d)) is reported. Reaction these with PdCl2 in refluxing acetonitrile affords the complete series square planar complexes, Pd(CzTrR)Cl (7a–d) Pd(CzTR)Cl (8a–d). analogous platinum complexes are prepared by deprotonation ligand carbazole nitrogen under followed reaction Pt(COD)Cl2 to give Pt(CzTrR)Cl (9b, 9d) Pt(CzTR)Cl (10b, 10d). X-ray structure (5b, 5c, 6c) their metal (8b, 8d, 9b) Complexes 7–10d were examined cyclic voltammetry DFT calculations shed light on electronic structures. Pd Pt same (CzTr: 7d, 9d; CzT: 10d) showed very similar oxidation potentials suggesting lowest based. In contrast, oxidations tetrazole 7d 9d notably more difficult than triazole 8d 10d. Both observations supported that indicate HOMO essentially ?-bonding character.