Coordination chemistry and structural rearrangements of the Me2PCH2AlMe2 ambiphilic ligand

Reaction of 2 equivalents of (Me2PCH2AlMe2)(2) with [{RhCl(cod)}(2)] (cod = 1,5-cydooctadiene) afforded [{kappa P-2,P-(Me3Al)ClMeAl(CH2PMe2)(2)}Rh(cod)] (1), which features a kappa(2)-coordinated bis(phosphino)aIuminate anion. In compound 1, an Al-Cl substituent bridges to a molecule of AlMe3, which could be removed in vacuo to provide [{kappa P-2,P-ClMeAl(CH2PMe2)(2)}Rh(cod)] (2). By contrast, reaction of 1 equiv. of (Me2PCH2AlMe2)(2) with [{RhCl(cod)}(2)] yielded [Rh(cod(mu-Cl)(Me2PCH2AlMe2)] (3) as the major product, where the phosphine donor of an intact Me2PCH2AlMe2 ligand is coordinated to rhodium and a chloride ligand bridges between Rh and Al. [Rh(cod)(mu-Cl)(Me2PCH2AlClMe)] (3A) and 2 were also formed as minor products. The aforementioned reactions were carried out in benzene or toluene, whereas the 1: 1 reaction of (Me2PCH2AlMe2)(2) with [{RhCl(cod)}(2)] in THE afforded [{Rh(mu-CH2PMe2)(cod)}(2)] (4). Reactions of (Me2PCH2AlMe2)(2) with iridium(I), gold(I) and platinum(II) precursors were also explored. A 1: 1 reaction of (Me2PCH2AlMe2)(2) with [{IrCl(cod)}(2)] afforded [{kappa P-2,P-Cl2Al(CH2PMe2)(2)}Ir(cod)] (5) as one of two major phosphine-containing products; unlike 3, this compound features two chlorine substituents on aluminium. For comparison, the rhodium analogue of 5, [{kappa P-2,P-Cl2Al(CH2PMe2)(2)}Rh(cod)] (6), was also synthesized via the 1: 1 reaction of {ClAl(CH2PMe2)(2))(2) with [{RhCl(cod)}(2)]. Reactions of (Me2PCH2AlMe2)(2) with [AuCl(CO)] or [PtCl2(cod)] also resulted in chloride-methyl group exchange between the transition metal and aluminium. However, these reactions generated free (Me2PCH2AlClMe)(2) accompanied by gold and ethane, or [PtMe2(cod)], respectively. Reaction of 1.5 equivalents of (Me2PCH2AlMe2)(2) with [PtMe2(cod)] at 75 degrees C afforded zwitterionic [(PtMe{mu-kappa P-1:kappa P-2,P-MeAl(CH2PMe2)(3)})(2)] (7) which features two tris(phosphino) aIuminate anions bridging between PtMe units. Compounds 1-2, 3/3A, 4-7 and (Me2PCH2AlClMe)(2) were crystaographicay characterized.

Automated summary

This study investigates the products of the reaction between (Me2PCH2AlMe2)(2) and transition metal precursors, as well as the effect of reaction conditions on the products. The structures of the products are determined by crystallography.