Unusual perchlorate binding in heptacoordinated cadmium(II)thiocyanate containing a pentadentate Schiff base

A new Schiff base, N,N′-(bis(pyridin-2-yl)benzylidene)diethylenetriamine (bpbd), has been used to synthesise a novel heptacoordinated cadmium(II)thiocyanate complex [Cd(bpbd)(NCS)(ClO4)] (1). Crystal structure analysis of 1 reveals cadmium(II) centre in a distorted pentagonal bipyramid environment with perchlorate binding, C–H⋯O hydrogen bonding and C–H⋯π interaction leading to a 2D sheet. 1 displays intraligand 1(π–π*) fluorescence and intraligand 3(π–π*) phosphorescence in glassy solutions (MeOH at 77 K).