Synthesis, Crystal Structure, and Molecular Structure of Maleate Tris(Benzohydrazide) Cobalt(II) Tetrahydrate [Co(L1)3](Mal) · 4H2O and Maleate Tris(Phenylacethydrazide) Nikel(II) Monohydrate [Ni(L2)3](Mal) · H2O

Abstract

Coordination compounds [Co(L¹)₃](Mal) · 4H₂O (I) and [Ni(L²)₃](Mal) · H₂O (II) (L¹ is benzohydrazide, L₂ is phenylacethydrazide, and H₂Mal is maleic acid) have been synthesized and characterized by IR spectroscopy and diffuse reflectance spectroscopy. Crystal structures of I and II have been determined by single-crystal X-ray diffraction. Structural units of crystals I and II are complex cations [Co(L¹)₃]²⁺ and [Ni(L²)₃]²⁺, respectively, maleate-ions Mal^2–, and crystallized water molecules bound by a branched system of hydrogen bonds. Metal atoms at the complex cations of crystals I and II have octahedral coordination (3O + 3N) formed by three bidentate chelate ligands Lⁿ (n = 1, 2).