Cyclopalladated complexes based on 2-phenylbenzothiazole and 1,4-(benzothiazol-2-yl)benzene with acetate ligands and ethylenediamine
摘要:
Complexes [Pd(bt)En]ClO4, [Pd(bt)(mu-OOCCH3)](2), [(PdEn)(2)(mu-dbt)](CH3COO)(2), and [Pd-2(mu-dbt)center dot (mu-OOCCH3)(2)](2) (bt(-) and dbt(2-) are the mono- and bisdeprotonated forms of 2-phenylbenzothiazole and 1,4-bis-(benzthiazol-2-yl)benzene, En is ethylenediamine) are characterized by H-1 NMR, electron absorption spectroscopy, and voltammetry. The upfield shift of the signal of protons of heterocyclic ligands in complexes with acetate ligands is assigned to anisotropic effect of the ring current of the two fragments {Pd(bt)} and {Pd(dbt)} in the complexes. The red shift of the optical transition of the metal-ligand charge transfer as well as the anodic shift of the ligand-centered reduction of [(PdEn)(2)(mu-dbt)](CH3COO)(2) relative to [Pd(bt)En]ClO4 is due to the decrease in the LUMO energy of the complexes. The cathodic shift of the oxidation potential and the long wavelength absorption in complexes with acetate ligands is assigned to variation in the HOMO nature due to the metal-metal bond formation.