FORMATION OF THE DECAHYDRO(TRIMETHYLPHOSPHINE)PENTABORATE(1-) ANION AND AN ISOMER OF TRIMETHYLPHOSPHINE PENTABORANE(11)

Trimethylphosphine-pentaborane(9) combined with H- to form a new, stab le polyborane complex anion, decahydro(trimethylphosphine)pentaborate( 1-) [B5H10.P(CH3)3-]. The potassium and sodium salts of the anion coul d be isolated as white solids at room temperature. The anion also form ed when B5H9.P(CH3)3 was treated with KOH(s) or KOCH3(s). The reaction of the anion with HCl in tetrahydrofuran gave 1-trimethylphosphine-pe ntaborane(11) [1-P(CH3)3.B5H11] as an unstable intermediate which even tually converted into B4H8.P(CH3)3 and BH2Cl.THF.