A zwitterionic carbene-stannylene adduct via cleavage of a dibenzotetraazafulvalene by a stannylene

Reaction of the tetraamine 1,2-C6H4-[NHCH2CH2N(CH3)(2)](2) (8) with bis(bis (trimethylsilyl)amido)tin(II) yields the N-heterocyclic stannylene 1, 2-C6H 4-[NCH2CH2N(CH3)(2)](2)Sn (9) which contains additional 2-(dimethylamino)et hyl groups at the nitrogen atoms of the five-membered ring. These additiona l donor groups provide for an intramolecular stabilization of the electron deficient tin center. The X-ray structure analysis with crystals of 9 shows two three-coordinated tin atoms with different coordination environments i n a dinuclear complex. Reaction of the stannylene 9 with the N,N'N"N"' tetr amethyldibenzotetraazafulvalene 4 leads via C=C bond cleavage in the dibenz otetraazafulvalene to the yellow carbene-stannylene adduct 10. The X-ray st ructure analysis of 10 reveals bond parameters consistent with a zwitterion ic species made up from a partially cationic carbene subunit and a partiall y anionic stannylene unit. (C) 2001 Elsevier Science B.V. All rights reserv ed.