Reactivity of allylphosphines with iridium complexes: Diallylphosphines as new bidentate ligands

✍ Scribed by Edgar Ocando-Mavarez; Merlin Rosales; Ninoska Silva

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 217 KB
• Volume: 9
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/(sici)1098-1071(1998)9:2<253::aid-hc21>3.0.co;2-p

✦ Synopsis

Addition of four equivalents of t-butyldiallylphosphine 1a to a solution of one equivalent of [(COE) 2 IrCl] 2 in CHCl 3 at low temperature produced two isomers of the complex [t-Bu(C 3 H 5 )PCH 2 CH‫ס‬CH)]IrHCl(COE)-[PtBu(C 3 H 5 ) 2 ] (2a), which evolve at 40ЊC to [t-Bu(C 3 H 5 )PCH 2 CH‫ס‬CH)]IrCl(C 8 H 15 )[PtBu(C 3 H 5 ) 2 ] (3a), by a hydride transfer from iridium to the cyclooctene (COE) ligand. It is reasonable that the unsaturation at the iridium center is fulfilled by interactions with the allyl moieties of the phosphine that are not metalated. This has been demonstrated by bubbling CO into a solution of 3a in CHCl 3 at room temperature to obtain the carbonyl complex [t-Bu(C 3 H 5 )-PCH 2 CH‫ס‬CH)]Ir(CO)Cl(C 8 H 15 )[PtBu(C 3 H 5 ) 2 ] (4a).

Under the same conditions, the reaction of diisopropylamindiallylphosphine 1b and anisyldiallylphosphine 1c afforded a mixture of isomers 3b and 3c, respectively. These results show that diallylphosphines can be considered to be a new family of bidentate ligands. Finally, the reaction of these phosphines with [(COD)IrCl] 2 (COD ‫ס‬ 1,5 cyclooctadiene) shows the formation of tetracoordinated iridium (I) complexes IrCl(COD)(PR3), which are thermally stable. ᭧ 1998