Synthesis and characterization of cadmium, copper and zinc complexes with scorpionate ligand hydrotris[3-(p-anisyl)-5-methylpyrazol-1-y1]borate [HB{pz^An,^Me}₃] X-ray structure of [Cd(OAc)(Hpz^Me,^An) (HB{pz^An,^Me}₃)]· CH₂Cl₂

A series of new scorpionate complexes, CdCl(Hpz^Me,^An) (HB{pz^An,^Me}₃) (1), [Cd(OAc)(Hpz^Me,^An) (HB{pz^An,^Me}₃)]· CH₂Cl₂ (2), ZnCl(HB{pz^An,^Me} ₃) (3), Zn(OAc)(HB{pz^An,^Me}₃) (4), Cu(OAc)(Hpz^Me,^An)(HB{pz^An,^Me }₃)·CH₂Cl₂ (5) and [CuCl(Hpz^Me,^An)(HB{pz^An,^Me }₃)]·CH₂Cl₂ (6), were prepared by reacting MX₂ (M = Cd²⁺, Zn²⁺, Cu²⁺; X = Cl^-, OAc^-) with ligand, K[HB{pz^An,^Me}₃] [pz^An,^Me = 3-(p-anisyl)-5-methylpyrazolyl]. The zinc ion in complexes 3 and 4 are four-coordinate, while copper and cadmium is five-coordinated with an additional substituted pyrazole, Hpz^Me,^An in 1, 2, 5 and 6. The infrared bands v_as(CO₂) and v_s(CO₂) indicate acetate is an unidentate ligand in 2 and 4, but a bridging one or an intermediate mode between unidentate and bidentate ligand in 5. The ¹H NMR spectra of 1 and 2 show threefold symmetry in solution. The ESR spectra of 5 and 6 in CH₂Cl₂ exhibit a pseudoaxial symmetrical {d_x2-y2}¹ configuration at copper The single crystal structure of 2 shows that the coordination environment around Cd²⁺ is a distorted square pyramidal, with a N atom of tridentate HB{pz^An,^Me}₃ apical. The acetate acts as a unidentate ligand, and an intramolecular N-H·O hydrogen bond exists between the uncoordinated oxygen of acetate and the pyrazolic proton.