Main group pyrazolates - The X-ray structures of [Al(η²-Bu^t ₂pz)₃], [SnMe₃(η¹-Ph₂pz)] and [GePh₃(η¹-Bu^t ₂pz)] (R₂pz = 3,5-disubstituted pyrazolate)

From metathesis reactions between AlCl₃, SnMe₃Cl, or GePh₃Br and the appropriate potassium 3,5-disubstituted pyrazolate [K(R₂pz)] the complexes [Al(Bu^t ₂pz)₃], [SnMe₃(Bu^t ₂pz)], [SnMe₃(Bu^t ₂pz)], and [GePh₃(Bu^t ₂pz)] have been obtained. The X-ray structure of [Al(Bu^t ₂pz)₃] shows the complex to be monomeric with η²-pyrazolate groups, in a quasi-trigonal prismatic array: the first monomeric homoleptic tris(pyrazolato) complex of any element. X-Ray structures of [SnMe₃(Ph₂pz)] and [GePh₃(Bu^t ₂pz)] reveal mononuclear species with distorted tetrahedral stereochemistries and η¹-pyrazolate groups. Comparisons of spectroscopic data between [SnMe₃(Ph₂pz)] and [SnMe₃(Bu^t ₂pz)] suggest the latter is also four-coordinate with an η¹-Bu^t ₂pz ligand.