Rhenium(I) complex with 2-(benzothiazol-2-yl) quinoline: Synthesis, characterization, spectral properties and DFT/TDDFT investigations

Abstract

The red colored mononuclear rhenium(I) complex having fac-[Re(CO)₃]⁺ moiety of general formula, [Re(CO)₃(NÇN)Cl], has been synthesized in excellent yield by reacting [Re(CO)₅Cl] with 2-(benzothiazol-2-yl) quinoline (1:1) in a boiling mixture of methanol+chloroform (3:1, v/v) under argon atmosphere. Elemental, ¹H and ¹³C NMR analysis show the formation of the desired complex. The complex is also characterized by different spectroscopic techniques. The ground and excited-state geometries, NMR, absorption, and phosphorescence properties of the Re(I) complex are examined by DFT and TDDFT methods. The natural transition orbital and spin density difference map analysis reveals the nature of excitations. The lowest lying triplet excited state is associated with the ³MLCT/³ILCT excited state. The emission-like transition is consistent with the strong ³MLCT/ ³ILCT character.