Organometallic coordination polymers: Sn(IV) derivatives with the bis(triazolyl)methane ligand

摘要

Several alkyl- or aryl-tin(IV) halides of general formula SnR _nX_(4-n) (n = 0-2; R = Me, Et, ~nBu, ~tBu, Ph; X = Cl, Br), possessing Lewis acidic character, have been reacted with the polydentate N-donor ligand bis(1,2,4-triazolyl)methane (Btm), affording Btm(SnR_nCl_(4-n)) complexes. (Btm) _2Sn~nBu_2Br_2 and (Btm)Sn ~nBu_2(NO_3)_2 are also reported. These materials were characterized by elemental analyses, IR and ~1H (and, in selected cases, ~(119)Sn) NMR spectroscopy, and, were possible, ab initio X-ray powder diffraction methods. The crystal structures determined by the latter method showed that Btm ligands, in the exobidentate mode, link Sn(IV) fragments which lie 9.5-11.2 apart (depending on the Btm conformation and on the local metal stereochemistry), in one-dimensional chains packed in parallel bundles. The main geometrical features of these 1D polymers are compared with those of the bis(imidazolyl)methane complexes and of the known Btm derivative, Btm(Ph_2SnBr_2). Interestingly, the expected isomorphous structures for selected couples was not found, as if very subtle energetic differences were driving the crystallization of these species into different structure types.