Cyclodiphosphazane appended with thioether functionality: Synthesis, transition metal chemistry and catalytic application in Suzuki-Miyaura cross-coupling reactions

Abstract

The coordination chemistry of thioether functionalized cyclodiphosphazane ligand, cis-{(t)BuN-P(OCH(2)CH(2)SCH(3))}(2) (1) is described. The reactions of 1 with [Pd (COD) Cl(2)] in 1:1, 1:2 and 2:1 M ratios afforded cis-[PdCl(2){tBuNP(OCH(2)CH(2)SCH(3))}(2)] (2), cis-[{PdCl(2)}(2){(t)uNP(OCH(2)CH(2)SCH(3))}(2)] (3) and trans-[ PdCl(2){((t)BuNP(OCH(2)CH(2)SCH(3)))(2)}(2)] (4), respectively. Treatment of 1 with [Pd(PEt(3)) Cl(2)](2) or [PdCl-(eta(3)-C(3)H(5))](2) in appropriate molar ratios produce the mono-and binuclear complexes [PdCl(2)(PEt(3){(t)BuN-P( OCH(2)CH(2)SCH(3))}(2)] (5) and [{PdCl(eta(3)-C(3)H(5))}(2){(t)BuNP(OCH(2)CH(2)SCH(3))}(2)] (6) in good yield. The reaction of 1 with [{Ru(p-cymene) Cl(2)}(2)] afforded the mononuclear cationic complex, [{(p-cymene) RuCl{(t)BuN-P( OCH(2)CH(2)SCH(3))}(2)] Cl (7), whereas the reactions of [Rh(COD) Cl](2), [Pt(COD) Cl2] and [Au(SMe(2)) Cl] with 1 yielded the corresponding P-coordinated neutral complexes, [RhCl(COD){(t)BuNP(OCH(2)CH(2)SCH(3))}(2)] (8) cis-[PtCl(2){tBuNP(OCH(2)CH(2)SCH(3))} 2] (9), respectively. The binuclear palladium(II) complex 3 was found to be an effective catalyst for the Suzuki-Miyaura cross-coupling reactions. (C) 2011 Elsevier B.V. All rights reserved.