TERTIARY PHOSPHINE ADDUCTS OF ALANE AND GALLANE

Thermally stable mono-tri-t-butylphosphine adducts of alane and gallane, H3MPtBu3 (M = Al, 1; M = Ga, 2) and the gallane rich adducts of 1,2-bis(diisopropylphosphino)ethane and 1,2-bis(diphenylphosphino)ethane, [(H3Ga)2{(PR2CH2)2}] (R = (i)Pr, 3; R = Ph, 4), have been prepared from LiMH4/HCI/phosphine; reactions involving H3MNMe3/PtBu3 also yield 1 and 2, for the former via a mixed donor tBu3PAl(H)3NMe3 (5), which decomposes to 1 and NMe3 at ca. 40-degrees-C; compounds 1 and 2, and the previously reported alane analogue of 3,. viz. [(H3Al)2{(PiPr2CH2)2}](6) have been shown to be four coordinate (Al-P, 2.471(3) and 2.451(3) angstrom, 1 and 6; Ga-P 2.444(6) angstrom, 2). Ab initio calculations on relevant model systems, H3GaPMe3 (DZP level) and H3Al(PR3)2 (R = H or Me; D95* level) are reported, Ga-P 2.550 angstrom, and Al-P 2.828 angstrom (R = H), 2.786 angstrom (R = Me).