Bisamino(diphosphonite) with dangling olefin functionalities: synthesis, metal chemistry and catalytic utility of Rh(I) and Pd(II) complexes in hydroformylation and Suzuki-Miyaura reactions.

Bisamino(diphosphonite), p-C6H4{N{P(OC6H4C3H5-o)2}2}2 (1), was prepared by reacting p-C6H4{N(PCl2)2}2 with four equivalents of o-allylphenol in 85% yield. Compound 1 on treatment with [M(CO)4(HNC5H10)2] (M = Mo or W) gave cis-[{M(CO)4}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (2, M = Mo; 3, M = W). The reaction of 1 with [Fe(η(5)-C5H5)(CO)2]2 yielded the complex [{Fe(η(5)-C5H5)(μ-CO)}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (4). Treatment of 1 with Fe(CO)5 furnished a mononuclear complex, [{Fe(CO)3}2{p-C6H4{N{P(OC6H4C3H5-o)2}2}2}] (5). The ruthenium(II) complex, [{(η(6)-p-cymene)Ru(μ-Cl)3RuCl}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (6), was obtained on treatment of ligand 1 with [(η(6)-p-cymene)Ru(Cl)2]2. The reaction between 1 and [Rh(COD)Cl]2 (COD = 1,5-cyclooctadiene) in dichloromethane resulted in the formation of a dinuclear complex [{RhCl}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (7), in which the allyl double bond of one of the phenoxy groups coordinates to the metal center. When ligand 1 was reacted with two equivalents of [Pd(COD)Cl2], a dinuclear complex [{PdCl2}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (8) was obtained. With copper(I) halides, ligand 1 afforded tetranuclear complexes, [{(Cu(μ-X)(NCCH3))2}2{p-C6H4{N(P(OC6H4C3H5-o)2)2}2}] (9, X = Cl; 10, X = Br; 11, X = I). Reaction of 1 with four equivalents of [AuCl(SMe2)] produced a tetranuclear complex, [(AuCl)4{p-C6H4{N{P(OC6H4C3H5-o)2}2}2}] (12). Complex 8 shows excellent catalytic activity in the Suzuki-Miyaura cross-coupling reaction under microwave conditions and complex 7 catalyzes hydroformylation of styrenes with good TONs.