Effect of N-salicylidene hydrazide protonation on the solid state structural diversity of its Cu(ii), Ni(ii) and Zn(ii) complexes†
We present here ten coordination compounds isolated from reactions of divalent metal ions (CuII, NiII and ZnII) with the Schiff base ligand H2L derived from salicylaldehyde and ω-hydroxy carbonic acid hydrazide. Protonation levels of the ligand has played significant roles in affecting the coordination conformations of the metallosupramolecular compounds in solid state. Four kinds of complexes have been obtained: monomeric [M(HL)2] and dimeric [M2(HL)2(X)2]/[M2(HL)2](X)2 (X = anion) containing monodeprotonated ligand, and polymeric ∞1M(L) and dimeric [Zn2L2] compounds with the doubly deprotonated form of the ligand. The structures of the free ligand H2L and its complexes [Zn(HL)(H2L)]·(NO3)·EtOH (Zn-1a), [Cu2(HL)2(NO3)2] (Cu-3a), [Cu2(HL)2(SiF6)] (Cu-3b) and [Ni2(HL)2(EtOH)(H2O)](NO3)2(Ni-3a) were elucidated by single-crystal X-ray diffraction. The reactivity of [Ni(HL)2] complex in the presence of a competitive ligand was investigated.
- This article is part of the themed collection: Crystal Engineering Techniques