SYNTHESIS AND CRYSTAL-STRUCTURE OF THE FIRST POLYMERIC CESIUM COMPOUND OF IT CARBORANE LIGAND SYSTEM

The reaction between a THF solution of (SiMe3)(4)C4B8H8 (1) and excess cesium metal, in the absence of either naphthalene or aromatic solven ts, produced a paramagnetic intermediate that reacted further with ces ium to give the EPR-silent species Cs(TMEDA)-1-Cs-2,4,7,9-(SiMe3)(4)-2 ,4,7,9-C4B8](n) (2). Single-crystal X-ray analysis showed 2 to be a po lymeric structure in, which each C4B8 carborane fragment serves as a l igand to two Cs atoms and is bonded to one through an open six-membere d face and to the other via upper- and lower-belt M-H-E (where E = B, C) interactions.