Synthesis, spectral characterization, thermal and photoluminescence properties of Zn(II) and Cd(II)-azido/thiocyanato complexes with thiazolylazo dye and 1,2-bis(diphenylphoshino)ethane

A series of complexes of the type [M(L)(dppe)X2]; where M = Zn(II) or Cd(II); L = 4-(2′-thiazolylazo)chlorobenzene (L1), 4-(2′-thiazolylazo)bromobenzene (L2) and 4-(2′-thiazolylazo) iodobenzene (L3); dppe = 1,2-bis(diphenylphosphino)ethane; X = N3− or NCS− have been prepared and characterized on the basis of their microanalysis, molar conductance, thermal, IR, UV–vis and 1H NMR spectral studies. IR spectra show that the ligand L is coordinated to the metal atom in bidentate manner via azo nitrogen and thiazole nitrogen. An octahedral structure is proposed for all the complexes. The thermal behavior of the complexes revealed that the thiocyanato complexes are thermally more stable than the azido complexes. All the complexes exhibit blue-green emission with high quantum yield as the result of the fluorescence from the intraligand emission excited state.