Rm. Kabbani et al., Synthesis and crystal structure of a new hexahydro-closo-hexaborate copper(I) complex Cu-2[(C6H5)(3)P](4)B6H6, INORG CHEM, 38(16), 1999, pp. 3748
The reaction of hexahydro-closo-hexaborate(2-) with copper(II) acetate and
triphenylphosphine in acetonitrile yields the novel complex, Cu-2[(C6H5)(3)
P](4)B6H6. 2CH(3)CN. X-ray structural analysis shows that the complex cryst
allizes in the triclinic centro-symmetric space group, P (1) over bar, with
one molecule per unit cell. Each copper atom bonds to the hexaborate cage
through two edge borons, forming a three-center two-electron B-Cu-B bond. T
he copper in this complex exhibits a trigonal-planar geometry and is a coor
dinatively unsaturated 16-electron center.