Synthesis, crystal structure, and properties of the adduct of bis(O,O′-diisopropyl dithiophosphato)nickel(II) with pyridine [Ni(i-Pr₂dtp)₂(py)₂]

Abstract

A new adduct bis(pyridine)-bis(O,O′-diisopropyl dithiophosphato-S,S′)nickel(II), [Ni(i-Pr₂dtp)₂(py)₂] (dtp = dithiophosphate, py = pyridine) has been obtained by re-crystallization from CH₃COCH₃. The crystal and molecular structure of the title complex has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group P2₁/c, with lattice parameters a = 6.4890(13) Å, b = 16.386(3) Å, c = 14.830(3) Å, β = 99.74(3)°, V = 1554.1(5) ų, and Z = 2. The crystal structure consists of discrete molecules of [Ni(i-Pr₂dtp)₂(py)₂], which displays a slightly distorted octahedral geometry for the NiS₄N₂ chromophore. Two O,O′-diisopropyl dithiophosphate ions act as bidentate ligands with their S atoms coordinated to Ni atom. Each forms a four-membered chelate ring in the equatorial plane. The N atoms from two pyridine ligands are axially coordinated to the Ni atom. The Ni$---{\text{S}}$S bond distances are 2.4492(8) Å and 2.5711(9) Å, and the Ni$---{\text{N}}$ bond distances are 2.127(3) Å. Thermal analyses show that the thermal decomposition of this adduct is so unstable that loss of two pyridine ligands begins at about 65°C. Electronic and IR spectra data is in agreement with the structural data.