Inorganic Chemistry, Vol.51, No.9, 5070-5081, 2012
Sensitivity of Silver(I) Complexes of a Pyrimidine-Hydrazone Ligand to Solvent, Counteranion, and Metal-to-Ligand Ratio Changes
Metal complexation studies were performed with AgSO3CF3 and AgBF4 and the ditopic pyrimidine-hydrazone ligand 6-(hydroxymethyl)pyridine-2-carboxaldehyde (2-methylpyrimidine-4,6-diyl)bis(1-methylhydrazone) (1) in both CH3CN and CH3NO2 in a variety of metal-to-ligand ratios. The resulting complexes were studied in solution by NMR spectroscopy and in the solid state by X-ray crystallography. Reacting either AgSO3CF3 or AgBF4 with 1 in either CH3CN or CH3NO2 in a 1:1 metal-to-ligand ratio produced a double helicate in solution. This double helicate could be converted into a linear complex by increasing the metal-to-ligand ratio; however, the degree of conversion depended on the solvent and counteranion used. Attempts to crystallize the linear AgSO3CF3 complex resulted in crystals with the dimeric structure [Ag(2)1(CH3CN)(2)](2)(SO3CF3)(4) (2), while attempts to crystallize the AgSO3CF3 double helicate from CH3CN resulted in crystals of another dimeric complex, [Ag(2)1(SO3CF3)(CH3CN)(2)](2)(SO3CF3)(2)center dot H2O (3). The AgSO3CF3 double helicate was successfully crystallized from a mixture of CH3CN and CH3NO2 and had the structure [Ag(2)1(2)](SO3CF3)(2)center dot 3CH(3)NO(2) (4). The linear AgBF4 complex could not be isolated from the double helicate in solution; however, crystals grown from a solution containing both the AgBF4 double helicate and linear complexes in CH3CN had the structure [Ag(2)1(CH3CN)(2)](BF4)(2) (5). The AgBF4 double helicate could only be crystallized from CH3NO2 and had the structure [Ag(2)1(2)](BF4)(2)center dot 2CH(3)NO(2) (6).