Synthesis of Group 14 Metal Enamido, Alkenyl, Imido and Alkenyl‐Amido Complexes from a Monoanionic Pyridyl‐1‐azaallyl Ligand

The reactivity of the lithium pyridyl‐1‐azaallyl complex [Li{N(SiMe 3 )C(Ph)C(R)(C 5 H 4 N‐2)}] 2 [R = SiMe 3 ( 1 ) or H ( 10 )] with group 14 metal halides has been studied under various conditions. It undergoes a salt‐elimination reaction with MCl 2 (M = Ge, Sn or Pb) to form [Ge{C(C 5 H 4 N‐2)C(Ph)N(SiMe 3 ) 2 }{N(SiMe 3 )C(Ph)C(SiMe 3 )(C 5 H 4 N‐2)}] ( 2 ), [M{N(SiMe 3 )C(Ph)C(SiMe 3 )(C 5 H 4 N‐2)} 2 ] [M = Sn ( 3 ), Pb ( 4 )], and [M{N(SiMe 3 )C(Ph)C(SiMe 3 )(C 5 H 4 N‐2)}Cl] [M = Ge ( 5 ), Sn ( 6 ), Pb ( 7 )], where the azaaalyl moiety acts as a monodentate ligand. However, the reaction of 1 with GeCl 4 or HSiCl 3 forms [Ge{C(C 5 H 4 N‐2)C(Ph)N(SiMe 3 )}Cl 2 ] 2 ( 8 ) or [{(C 5 H 4 N‐2)C(SiMe 3 )C(Ph)N}(μ‐SiHCl)] 2 ( 9 ), respectively, by elimination of both the lithium salt and Me 3 SiCl; the reaction of 10 with GeCl 4 gives [{(C 5 H 4 N‐2)C(H)C(Ph)N}(μ‐GeCl 2 )] 2 ( 11 ) in a similar manner. X‐ray structural analysis of compounds 2 − 5 , 7 − 9 and 11 showed that the pyridyl‐1‐azaallyl ligand bonds to the metal center in enamido, alkenyl, alkenylamido, and imido bonding modes. A mechanism for the formation of these compounds is proposed and discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)