SYNTHESIS AND VIBRATIONAL SPECTROSCOPIC I NVESTIGATION OF [H3B-SE-SE-BH3](2-) AND [H3B-MU(2)-SE(B2H5)](-) - CRYSTAL-STRUCTURE AND THEORETICAL INVESTIGATION OF THE MOLECULAR-STRUCTURE OF [H3B-MU(2)-SE(B2H5)](-)

M(2)[H3B-Se-Se-BH3] 1 is produced by the reaction between elemental se lenium and MBH(4) (1:1) in triglyme (diglyme), under dehydrogenation. 1 reacts with an excess of B2H6 to give M[H3B-mu(2)-Se(B2H5)] 2 which is also formed in the reaction of THF . BH3 with 1. These reactions pr oceed under cleavage of the Se-Se bond and hydrogen evolution. [(C6H5) (4)P]Br reacts with Na . 2 to form [(C6H5)(4)P] . 2 which crystallizes in the tetragonal space group I4 (Nr. 82). An X-ray structure determi nation failed because of disordering of the cation and anion. B-11, Se -77 NMR shifts and (1)J((BH)-B-11-H-1) coupling constants as well as I R- and Raman spectroscopic investigations convey further structural in formation. Structural data of 2 have been calculated by SCF methods. T he anion of 2 may be viewed either as an adduct of Se with B3H8-, or a s a bridge substituted selena derivative of B2H6.