Synthesis of the Tris(trimethylphosphine)tetrahydrotriboron(1+) Cation

Details of the reaction of B(2)H(4)[P(CH(3))(3)](2) with the C(C(6)H(5))(3)(+) cation for the synthesis of the B(3)H(4)[P(CH(3))(3)](3)(+) cation are described. The reaction was thought to proceed through the formation of the "B(2)H(3)P[(CH(3))(3)](2)(+)" cation followed by the cluster expansion reaction with B(2)H(4)[P(CH(3))(3)](2). The triborane complex cation was fluxional with respect to the migration of the four borane hydrogen atoms. The (11)B, (31)P, and (1)H NMR chemical shifts were determined at low and high temperatures. The (11)B, (31)P, and (19)F NMR data for BF(3)P(CH(3))(3), a byproduct in the above reaction, were also reported.