Synthesis, structural, and spectroscopic study of rhenium(III) and rhenium(V) 4,6-dimethylpyrimidine-2-thiolate/triphenylphosphine mixed complexes: Crystal and molecular structure of ∥ReCl2(pymS)(PPh3)2∥·C3H6O and ∥ReOCl2(pymS)(PPh3)∥

4,6-dimethylpyrimidine-2(1H)-thione reacts with rhenium(V) precursors trans-∥ReOX3(PPh3)2∥ (X=Cl, Br) in acetone, to afford two classes of crystalline pyrimidinethiolate/triphenylphosphine mixed complexes:trans-∥ReIIIX2(C6H7N2S)(PPh3)2∥·C3H6O and ∥RevOX2(C6H7N2S)(PPh3)∥ (X=Cl, Br). The crystal structures of trans-∥ReCl2(C6H7N2S)(PPh3)2∥·C3H6O (I) and ∥ReOCl2(C6H7N2S)(PPh3)∥ (II) have been determined from single-crystal diffractometer data and refined to R factors of 0.0496 and 0.0365, respectively. (I) crystallizes in the triclinic space group P-1 with a=16.875(4), b=13.969(7), c=9.510(2) Å;α=81.78(2)°, β=85.15(12)°, γ=107.97(8)° and Z=2. The coordination geometry around the rhenium center exhibit mutually trans phosphine groups and chloride ligands disposed trans to the nitrogen and sulfur donors of the pyrimidinethiolate ligand which form a four-membered chelate ring with the metal. (II) crystallizes in the monoclinic space group P21/c with a=12.554(3), b=10.501(1), c=19.200(5) Å;β=106.54(2)° and Z=4. The rhenium atom presents a very distorted octahedral configuration with a chlorine atom trans to phosphine ligand in the axial position and the N,S-chelate ligand in the equatorial plane with the sulfur donor atom trans the Re=Ooxo group. The compounds were characterized also by means of ir and nmr spectroscopic measurements; reaction pathways are discussed on the basis of structural data. © 1989 Plenum Publishing Corporation.