Heterofunctionalized phosphines derived from (2-formylphenyl)diphenylphosphine and their reactions with oxorhenium(V) complexes

Reactions of [ReOCl3(PPh3)2] with a potentially tridentate Schiff base derived from (2-formylphenyl)diphenylphosphine and 2-aminophenol, HL1P, (HL1P = Ph2PC6H4-2-HCN(C6H4-2-OH)) result in a rapid decomposition of the Schiff base and the formation of a large number of hitherto non-identified metal-containing species, while from similar reactions with the analogoue phosphine oxide HL1PO, (HL1PO = Ph2P(O)C6H4-2-HCN(C6H4-2-OH)) products of the compositions [ReOCl2(PPh3)(L1PO)] (1) and [Re(NC6H4-2-OH)Cl3(PPh3)2] (2) could be isolated. The structure of 2 is an experimental proof of the preceding, metal-induced cleavage of the C–N double bond. A subsequent reaction of the released 2-aminophenol forms the final phenylimido ligand.Reduction of HL1P with NaBH4 gives the phosphine amine H2L2P (H2L2 = Ph2P(C6H4-2-CH2NH(C6H4-2-OH))) in good yield. Reactions of H2L2P with common oxorhenium(V) complexes result in the formation of the stable rhenium(V) complex [ReOCl2(HL2P)] (3) with a facially coordinated HL2P− ligand.

Reactions of [ReOCl3(PPh3)2] or (NBu4)[ReOCl4] with Schiff bases derived from (2-formylphenyl)diphenylphosphine and 2-aminophenol result in a rapid decomposition of the imines. Representative rhenium complexes with decomposition products are presented.A stable Re(V) complex was isolated with a tridentate, facially coordinated phosphine amine, which was produced by reduction of a Schiff base with NaBH4.Figure optionsDownload as PowerPoint slide