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 Å3, Z= 4, R= 0.059 and R′= 0.074 for 1330 reflections with Fo > 4σ(Fo).