Higher carbene homologues:: Naphtho[2,3-d]-1,3,2λ2-diazagermole, -diazastannole, and attempted reduction of 2,2-dichloronaphtho[2,3-d]-1,3,2-diazasilole

N, N'-Dineopentyl-2, 3-diaminonaphthalene 1, obtained by reaction of 2,3-diaminonaphthalene With pivaloyl chloride and subsequent reduction, was dilithiated and cyclodisubstituted with SiCl4 to give dichloro-dineopentyl-naphtho[2,3-d]-1,3,2-diazasilole 2. Treatment of 2 With two equivalents of potassium in THF caused cleavage of the SiN ring. A silylene could not be detected. The corresponding cyclic diaminogermylene 3 and diaminostannylene 4 were obtained by direct ring closure of 1Li(2), with GeCl2 dioxane or SnCl2, respectively, The compounds are structurally characterized by NMR and MS. The properties of 3 and 4 are compared with those of related germylenes and stannylenes. (C) 1998 John Wiley & Sons, Inc.