LAUSR

Abstract Density functional theory methods have been applied to identify the favoured structural motif of thallium(I) tris(pyrazolyl)methanide complexes. The reaction of [TlN(SiMe3)2]2 with tris(pyrazolyl)methane HC(pz)3 (with pz = pyrazolyl) in toluene furnished the highly air-sensitive title compound [Tl(HTpmd)] (4) (with HTpmd = [C(pz)3]−). An X-ray diffraction study revealed that complex 4 consists of a single bond between the thallium(I) cation and the carbanion of HTpmd ligand entity. This Tl–C bond (254.1(8) pm) is supported by two additional Tl⋯N contacts (Tl⋯N: 273.6(7) and 293.1 pm) provided by the N donor atoms of two pyrazolyl scaffolds of the tripodal ligand. Overall, a κ2N,κ1C coordination mode of the tris(pyrazolyl)methanide ligand is at hand in complex 4. Furthermore, the title compound forms a weak dimer in the solid-state by additional intermolecular Tl⋯N′ interactions (318.7 pm).