SYNTHESIS AND SOLID-STATE B-11-(H-1) MAS NMR INVESTIGATIONS OF SOME GROUP-11 ARACHNO-2-METALLATETRABORANES

The preparation and characterization (melting point, solution B-11-{H- 1} NMR, IR) of some new 2-arachno-argentatetraboranes and 2-arachno-cu pratetraboranes, [2-{(R(3)P)(2)M}B3H8] {M = Ag, R = 2-MeC(6)H(4), 4-CI C6H4, 4-MeOC(6)H(4), 2,6-(MeO)(2)C6H3; M = Cu, R = 4-CIC6H4, 2,6-(MeO) (2)C6H3} are reported and their solid state B-11 MAS (Magic Angle Spin ning) NMR spectra are compared with those obtained from the previously known metallatetraboranes {M = Ag, R = Ph, 4-MeC(6)H(4); M = Cu, R = Ph} and [NMe(4)][2-{M(CO)(4)}B3H8] (M = Cr, W). In contrast to the Cr and W derivatives, the Ag and Cu clusters exhibit only one signal in t heir solid state B-11 spectra consistent with an intramolecular boron exchange process which occurs in the solid state. Solid state B-11 MAS NMR spectra of Cs[B3H8] and [NMe(4)][B3H8] are also reported.