2,6-Dihalo-9-selenabicyclo[3.3.1]nonanes and their complexes with selenium dihalides: synthesis and structural characterisation.

The transannular addition of SeCl2 and SeBr2 to cis,cis-cycloocta-1,5-diene affords 2,6-dihalo-9-selenabicyclo[3.3.1]nonanes in high yields. The latter react with SeCl2 and SeBr2 to form the 2 : 1 complexes, which are the first representatives of coordination compounds with the Se…Se…Se bonds. X-ray crystallographic data of the obtained compounds are discussed. In contrast to 2,6-dihalo-9-selenabicyclo[3.3.1]nonanes, tetrahydroselenophene does not form complexes with SeCl2 and SeBr2 giving 1,1-dihalotetrahydroselenophenes. [ABSTRACT FROM AUTHOR]