1,2,3,5-Diselenadiazolyls as building blocks for molecular metals. Preparation and structures of [PhCN2Se2]+PF6− and [PhCN2Se2]2

The search for neutral, low-dimensional conducting materials has kindled interest in the preparation and study of heterocyclic thiazyl radicals, recent attention has been focused on 1,2,3,5-dithiadiazolyls. These planar seven-{pi}-electron radicals are known to associate in the solid state in one of two modes, (R = Ph) and 3(R = CF{sub 3}, NMe{sub 2}, Me{sup 6}). To date, however, there is no evidence of the desired packing mode, i.e., vertical stacks of uniformly spaced radicals. In order to test the effect on interdimer interactions of the replacement of sulfur by selenium, we have prepared and structurally characterized the hitherto unknown, 1,2,3,5-diselenadiazolyl (R = Ph).