Beryllium borohydride: complexes with trimethylphosphine and some other bases

Beryllium borohydride complexes, L,BeB2H8(L = Et2O, Me3P, Me2PH, Et3P, Me3N, and Me2NH) are liquid at room temperature and monomeric in benzene solution. Their formation has been followed tensimetrically. The trimethylphosphine complex, Me3PBeB2H8, absorbs a further mol. of trimethylphosphine giving a solid from which trimethylphosphine–borane and some free trimethylphosphine can be evaporated, leaving a viscous liquid residue, whose infrared spectrum contains the broad absorption at ca. 1750 cm.–1 characteristic of polymeric beryllium hydride.The infrared spectrum of beryllium deuteride, prepared from triphenylphosphine and beryllium borodeuteride is compared with that of beryllium hydride.