Synthesis, structure and properties of mononuclear cobalt(II) and cobalt(III) pseudohalide complexes containing N-donor Schiff bases: Synthetic control of metal oxidation levels

Two different sets of hexacoordinated cobalt(II) and cobalt(III) pseudohalide complexes have been prepared in combination with tetra- and tridentate N-donor Schiff bases, respectively. X-ray diffraction measurements of one representative member from each group, viz., trans-[Co(pfpd)(NCS)2] (1c) and mer-[Co(pbed)(N3)3] (2b) are done to define coordination sphere. All the complexes display intraligand 1(π-π*) fluorescence and intraligand 3(π-π*) phosphorescence in glassy solutions (MeOH at 77 K).