Thiosemicarbazide, hydrogen bonding

Both thiourea (tu) and thiosemicarbazide (tsc) are bifunctional ligands, containing a DD face in addition to one or two co-ordination sites. The reaction of [Zn(tu)4]2+ with a dicarboxylate normally occurs with displacement of thiourea to give coordination polymers of the type [Zn(tu)2(p-dicarboxylate)] in which the chains are cross-linked by DD-AA interactions [157]. The fumarate derivative contains identical inter-plane hydrogen bonding to that observed in (NEt4)2 [fumarate] 2tu [158], in which the zinc atom has formally been replaced by two tetraethylammonium cations. 

Bis(thiosemicarbazide)nickel(II) forms charge augmented double hydrogen-bonded chains with 1,4-terephthalate and trans-fumarate anions, which are further linked into sheets by hydrogen bonds between the N-H- -O units. The methylation of the primary amine disrupts these interactions markedly so that hydrogen-bonded sheets result, involving now molecules of water. ... 

Burrows. A.D. Mingos. D.M.P. White. A.J.P. Williams. D.J. Crystal engineering of metal complexes based on charge-augmented double hydrogen-bond interactions between thiosemicarbazides and carboxylates. Chem. Commun. 1996, (1). 97-99. 

It has been shown [113] that the arrangement of the non-hydrogen atoms in the thiosemicarbazide molecule is nearly planar and the sulfur atom and hydrazinic NH2 group are trans with respect to the C-N bond. When forming complexes... 

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