Investigation of silver salt metathesis: Preparation of cationic germanium(II) and tin(II) complexes, and silver adducts containing unsupported silver-germanium and silver-tin bonds

Syntheses of halide derivatives of germanium(II) and tin(II) aminotroponiminate (ATI) complexes and their silver salt metathesis reactions have been investigated. The treatment of GeCl2.(1,4-dioxane), SnCl2, or Snl(2) with [(n-Pr)(2)ATI]Li in a 1:1 molar ratio affords the corresponding germanium(II) or tin(II) halide complex [(n-Pr)(2)ATI]MX (where [(n-Pr)(2)ATI](-) = N- (n-propyl)-2-(n-propylamino)troponiminate; M = Ge or Sn; X = Cl or I). As usually expected, [(n-Pr)(2)ATI]GeCl and [(n-Pr)(2)ATI]SnCl undergo rapid metathesis with CF3SO3Ag, leading to trifluoromethanesulfonate salts, {[(n-Pr)(2)ATI]Ge}[SO3CF3] and {[(n-Pr)(2)ATI]Sn}[SO3CF3], and silver chloride. However, when the silver source [HB(3,5-(CF3)(2)Pz)(3)]Ag(eta(2)-toluene) is used, rather than undergoing metathesis, very stable 1:1 adducts [HB(3,5-(CF3)(2)Pz)(3)]Ag<--Ge(Cl)[(n-Pr)(2)ATI] and [HB(3,5-(CF3)(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI] are formed (where [HB(3,5-(CF3)(2)Pz)(3)](-) = hydrotris(3,5-bis(trifluoromethyl)pyrazolyl)borate). The use of the iodide derivative [(n-Pr)(2)ATI]SnI did not change the outcome either. All new compounds have been characterized by multinuclear NMR spectroscopy and X-ray crystallography. The Ag-Ge and Ag-Sn bond distances of [HB(3,5-(CF3)(2)Pz)(3)]Ag<--Ge(Cl)[(n-Pr)(2)ATI], [HB(3,5-(CF3)(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI], and [HB(3,5-(CF3)(2)Pz)(3)]Ag<--Sn(I)[(n-Pr)(2)ATI] are 2.4142(6)1 2.5863(6), and 2.5880(10) Angstrom, respectively. A convenient route to [(n-Pr)(2)ATI]H is also reported.