Se, a Bicyclic Polyselenide

Abstract

The structural diversity of polyselenide ions has once more been demonstrated. A decaselenadecalin anion Se can be prepared in over 70% yield by heating a polyselenide solution in dimethylformamide in the presence of [Ph 3 PNPPh 3 ]Cl and a trace of iodine. The product is isolated in the form of black crystals that correspond to a [Ph 3 PNPPh 3 ] ⊕ salt. The two bridgehead selenium atoms in this bicyclo[4.4.0] system are coordinated in such a way as to constitute a distorted pseudo‐trigonal bipyramid, with the bonding between them being equatorial/equatorial.