Syntheses and Crystal Structures of Heteroleptic Stannylenes and Germylenes

Two novel, monomeric heteroleptic derivatives of divalent Sn [Sn(2-{(Me 3 Si) 2 C}-C 5 H 4 N)R] [R = Sn(SiMe 3 ) 3 ( 1 ) or Si(SiMe 3 ) 3 ( 2 )] and divalent Ge [Ge(2-{(Me 3 Si) 2 C}-C 5 H 4 N)R] [R = Cl ( 3 ) or CH(PPh 2 ) 2 ( 4 )] have been prepared and characterized, and their molecular structures were determined by single-crystal X-ray diffraction. The stannylenes 1 and 2 were prepared from the corresponding heteroleptic chloro-analogue, [Sn(2-{(Me 3 Si) 2 C}-C 5 H 4 N)Cl]; 1 is the first structurally characterized compound to contain a bond between divalent Sn and tetravalent Sn and 2 is only the second structurally characterized example of a silyl-substituted heteroleptic stannylene. The Ge analogue of [Sn(2-{(Me 3 Si) 2 C}-C 5 H 4 N)Cl] ( 3 ) has been prepared and its utility as a precursor to further examples of heteroleptic germylenes demonstrated by the preparation and characterization of [Ge(2-{(Me 3 Si) 2 C}-C 5 H 4 N)CH(PPh 2 ) 2 ] ( 4 ).