Dimethylmetal(III) pyrazolides

The complexes Me₂Au(R₂pz) (R = H, Me; pzH = pyrazole) are formed on reaction of dimethylgold(III) nitrate with 3,5-disubstituted pyrazoles, R₂pzH, in water, but a similar procedure with Ph₂pzH followed by recrystallization from CHCl₃/CCl₄ gives [Me₂Au(Ph₂pzH)₂]NO₃ · ca.$\text{3}\text{4}$CCl₄. The complexes Me₂(Ph₂pz) (M = Au, Tl), Me₂In(Ph₂pz)·$\text{1}\text{2}$CH₂Cl₂, and Me₂Tl(Me₂pz) are formed on reaction of Me₂MI (M = Au, Tl) or Me₂InCl with Ag(R₂pz) in nonaqueous solvents. The complexes Me₂Au(R₂pz) (R = H, Me, Ph) are dimeric in chloroform and Me₂Tl(Me₂pz) is dimeric in benzene, but osmometric data for Me₂Tl(Ph₂pz) in benzene indicate presence of a monomer—dimer equilibrium.