Structures and Spectral Properties of Some Bis(β-diketonato)copper(II)Diazole Complexes. I. The 1:4 and 1:1 Adducts of Bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)copper(II) and 3-Methyl-1H-pyrazole

Abstract

Abstract Cu(hfac)2(5-Hmpz)4 (1) and Cu(hfac)2(5-Hmpz) (2) (Hhfac=1,1,1,5,5,5-hexafluoro-2,4-pentanedione; 5-Hmpz=5-methyl-1H-pyrazole) have been prepared by the stoichiometric reactions of Cu(hfac)2 with 3-methyl-1H-pyrazole in petroleum ether. The structures of 1 and 2 have been determined by X-ray analyses. Crystal data for 1: triclinic, P\bar1, a=9.531(1), b=10.286(2), c=8.891(2) Å, α=95.85(2), β=95.52(2), γ=85.41(1)°, V=860.9(3) Å3, Z=1, and R=0.061. Crystal data for 2: triclinic, P\bar1, a=9.647(6), b=12.075(9), c=9.130(5) Å, α=107.43(5), β=99.30(5), γ=87.20(6)°, V=1001.3(12) Å3, Z=2, and R=0.064. In 1, the geometry about each copper atom is approximately that of a tetragonal bipyramid, with four nitrogen atoms from 5-Hmpz molecules in the equatorial plane and two oxygen atoms from each hfac ligand in the axial positions. Each of the uncoordinated oxygen atoms of hfac ligands is intramolecularly hydrogen-bonded with two imino groups of adjacent 5-Hmpz molecules. In IR spectra, the split bands of νC–O were observed at 1648 and 1659 cm−1. In 2, each copper atom is approximately in an environment of a tetragonal pyramid, with an oxygen atom from a hfac ligand at the apex and a nitrogen atom from a 5-Hmpz molecule in the basal plane. The copper atom is located slightly above the plane. The split bands of νC–O were observed at 1644, 1662, 1669 cm−1. An interpretation of the observed IR spectral bands is proposed.