Structural manipulation through selective substitution of hydrogen bonding groups: the supramolecular structures of bis(thiosemicarbazidato)nickel complexes

Abstract

Deprotonation of a coordinated thiosemicarbazide by a dicarboxylate species competes with the previously reported formation of cation⋯anion tapes via charge-augmented hydrogen bonding between the thiosemicarbazide ligands and the carboxylates. This has resulted in the formation of five bis(thiosemicarbazidato)nickel complexes, [Ni(tscato)₂] (1), [Ni(Metscato)₂] (2), [Ni(Me₂tscato)₂] (3), [Ni(Me₃tscato)₂] (4) and [Ni(EtMe₂tscato)₂] (5), all of which have been structurally characterised [tscato = H₂NC(S)NNH₂, Metscato = HMeNC(S)NNH₂, Me₂tscato = H₂NC(S)NNMe₂, Me₃tscato = HMeNC(S)NNMe₂, EtMe₂tscato = HEtNC(S)NNMe₂]. [Ni(tscato)₂] has been structurally characterised before, though the crystal structure analysis of 1 reveals it to be a polymorph of the previously reported complex. The effect of removing hydrogen bond donors through the substitution of NH hydrogen atoms by alkyl groups on the supramolecular structure of the products is assessed.