Substitution of nitrido by the oxo group in reactions of [ReNCl2(PPh3)2] with multidentate N,O–-donor chelates. Crystal structure of [ReOCl2(PPh3)(HL)][H2L = 2,6-bis(hydroxymethyl)pyridine]

Abstract

The complex [ReNCl₂(PPh₃)₂] reacts with the potentially bidentate 8-hydroxyquinoline (Hquin) and N-phenylsalicylideneimine (Hpsal), and potentially terdentate ligands di-2-pyridyl ketone and 2,6-bis(hydroxymethyl)pyridine (H₂L) to form the products [ReOCl(quin)₂], [ReOCl₂(PPh₃)(psal)], [ReOCl₂{(C₅H₄N)₂C(O)(OH)}] and cis-[ReOCl₂(PPh₃)(HL)], respectively. The first three products are identical to those isolated earlier by the reactions of trans-[ReOCl₃(PPh₃)₂] with these ligands, while in the latter product the HL^– ligand acts as a bidentate N,O^–-donor, spanning one axial (O^–trans to ReO) and one equatorial co-ordination site. These reactions present an alternative synthetic route to monooxorhenium(V) complexes. The complexes cis-[ReOCl₂(PPh₃)(HL)] crystallizes in the orthorhombic space group P2₁2₁2₁ with cell parameters a= 10.019(3), b= 12.457(6), c= 19.53(1)Å, U= 2436.5 ų, Z= 4, R= 0.059 and R′= 0.074 for 1330 reflections with F_o > 4σ(F_o).