Molybdenum(0), ruthenium(II), palladium(II), platinum(II), copper(I) and gold(I) complexes of a new methoxy functionalised bis(phosphino)amine: synthesis and structure

Abstract

The synthesis, and characterisation, of a new functionalised bis(phosphino)amine Ph₂PN(o-C₆H₄OMe)PPh₂1 from o-H₂NC₆H₄OMe and 2 equiv. of Ph₂PCl in diethyl ether at 0°C is reported. Oxidation of 1 with either aqueous H₂O₂, elemental S₈ or grey Se affords the phosphorus(V) compounds Ph₂P(E)N(o-C₆H₄OMe)P(E)Ph₂ (E=O 2; S 3 or Se 4). Partial oxidation of 1 with 1 equiv. of S₈ in n-hexane affords the mixed P(III)/P(V) species Ph₂P(S)N(o-C₆H₄OMe)PPh₂5 in addition to small amounts of 3. Reaction of 1 (or 5) with [MX₂(cod)] (M=Pd, Pt; X=Cl or CH₃; cod=cycloocta-1,5-diene) affords either cis-[MX₂{Ph₂PN(o-C₆H₄OMe)PPh₂}] (M=Pd, X=Cl 6; M=Pt, X=Cl 7; M=Pt, X=CH₃8) or the neutral five-membered chelate complexes [MCl₂{Ph₂P(S)N(o-C₆H₄OMe)PPh₂}] (M=Pd 9, M=Pt 10) in which P,P- or P,S-chelation respectively was observed. Likewise reaction of [Mo(CO)₄(nbd)] (nbd=norbornadiene) or [Cu(MeCN)₄]PF₆ with 1 gave cis-[Mo(CO)₄{Ph₂PN(o-C₆H₄OMe)PPh₂}] 11 or [Cu{Ph₂PN(o-C₆H₄OMe)PPh₂}₂]PF₆12. Chloro-bridge cleavage and arene elimination of [{RuCl₂(p-cym)}₂] (p-cym=p-cymene) with 1 (1:2 metal:ligand ratio) affords, in good yield, the octahedral bis chelate ruthenium(II) complex trans-[RuCl₂{Ph₂PN(o-C₆H₄OMe)PPh₂}₂] 13. In contrast, reaction of 1 with two equiv. of [AuCl(tht)] (tht=tetrahydrothiophene) gave the dinuclear complex [(ClAu)Ph₂PN(o-C₆H₄OMe)PPh₂(AuCl)] 14 in which the bis(phosphino)amine P,P-bridges two {AuCl} metal fragments. All new compounds have been characterised by a combination of multinuclear NMR [¹H, ³¹P{¹H} and ¹⁹⁵Pt{¹H}], IR spectroscopy and elemental analyses. The molecular structures of six representative examples have been determined by single-crystal X-ray crystallography.