Syntheses, structures and luminescence behaviours of Group 12 metal(II) thiocyanate complexes with a tetradentate Schiff base: Variation in molecular and crystalline architectures with the change of congeneric metal ions

Das S. ; Bhar K. ; Chattopadhyay S. ; Mitra P. ; Smith V.J. ; Barbour L.J. ; Ghosh B.K. (2012)


One pentacoordinated mononuclear complex [Zn(L)(NCS)]PF 6 (1), one hexacoordinated 2D coordination polymer {[Cd 2(L)(NCS) 4]·0.24(CH 3OH)} n (2) and one pentacoordinated 1D polymeric chain [Hg 2(L)(SCN) 4] n (3) [L = N,N′-(bis(pyridine-2-yl)benzylidene)-1,4- butanediamine] have been synthesized and X-ray crystallographically characterized. Structural analyses revealed interesting variations in the coordination behaviour of the Schiff base (L) from tetradentate chelation to binucleating bis(bidentate) congregation on going from 1 to 2/3. The pseudohalide exhibits terminal N-coordination in 1, both μ 1,3 and μ 1,1 bridges in 2 and terminal S-coordination along with μ 1,1 linkages in 3. In 1/3, each pentacoordinated zinc(II)/mercury(II) centre adopts a distorted trigonal bipyramidal/square pyramidal geometry with a ZnN 5/HgN 2S 3 chromophore, whereas both Cd1 and Cd2 centres in 2 adopt a distorted octahedral geometry with CdN 3S 3 and CdN 6 chromophores, respectively. Weak intermolecular S⋯S and S⋯π interactions with multiple C-H⋯N hydrogen bonds promote the dimensionalities in 1-3. The complexes display intraligand 1(π-π) fluorescence in the solid state and in DMF solutions at room temperature. © 2012 Elsevier Ltd. All rights reserved.

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