A Stable Doubly Hydrogen-Bridged Butterfly-Shaped Diborane(4) Compound

作者：Shoji Yoshiaki; Matsuo Tsukasa^*; Hashizume Daisuke; Fueno Hiroyuki; Tanaka Kazuyoshi; Tamao Kohei

来源：Journal of the American Chemical Society, 2010, 132(24): 8258-+.

DOI：10.1021/ja102913g

In contrast to the common multiple bonding between carbon atoms, multiply bonded boron compounds have still been a synthetic challenge due to the electron deficiency of boron. We now report that a stable doubly hydrogen-bridged diborane(4), EindB(mu-H)(2)BEind, is produced by the two-electron oxidation of a hydrogen-substituted diborane(4) dianion [Li(+)(thf)](2)[Eind(H)BB(H)Eind](2-) where Eind denotes the 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl. The X-ray crystallography reveals a short B-B distance of 1.4879(7) angstrom in comparison with the normal B-B single bond length (1.72 angstrom), the presence of two hydrogen atoms bridged perpendicular to the B-B bond with a butterfly shape having a dihedral angle of the two BHB triangles of 113(1)degrees, and a linear geometry around the B-B bond with a C-B-B bond angle of 178.92(4)degrees. These structural data, experimental electron density analysis, and computational studies confirm the 3-fold bonding (a sigma and two pi-like bonds) between the two boron atoms incorporating the two bridging hydrogen atoms.

• 出版日期2010-6-23