Chiral functionalized bisphosphine ligands: Transition metal complexes of 1,2-bis(tert-Butylchlorophosphino)-1,2-dicarba-closo-dodecaborane(12)

When rac- or meso-1,2-bis(tert-butylchlorophosphino)-1,2-dicarba-closo-dodecaborane(12) (1a or 1b) is reacted with [M(CO)4(NBD)] (M = Cr, Mo, NBD = norbornadiene), [Mo(CO)4(EtCN)2] or [W(CO)6], rac-[Cr(CO)4{1,2-(PtBuCl)2C2B10H10}] (2), rac- or meso-[Mo(CO)4{1,2-(PtBuCl)2C2B10H10}] (3a or 3b) and rac-[W(CO)4{1,2-(PtBuCl)2C2B10H10}] (4) could be isolated as pure diastereomers. UV irradiation of 1 with [Cr(CO)6] in moist THF proceeds with hydrolysis and formation of [Cr(CO)4{1,2-(P(OH)tBu)2C2B10H10}] (5) which contains the metal complex-stabilized phosphinous acid. Compounds 2–5 were characterized spectroscopically (1H, 31P, 11B, 13C NMR), by mass spectrometry and by X-ray structure determination.

Graphical abstractrac- or meso-[M(CO)4{1,2-(PtBuCl)2C2B10H10}] (M = Cr, Mo, W) are readily obtained from rac- or meso-1,2-(PtBuCl)2C2B10H10. UV irradiation of 1,2-(PtBuCl)2C2B10H10 with [Cr(CO)6] in moist THF proceeds with hydrolysis and formation of [Cr(CO)4{1,2-(P(OH)tBu)2C2B10H10}].Figure optionsDownload full-size imageDownload as PowerPoint slide