Synthesis and structural characterization of dimethyltin(IV) complexes based on functionalized pyridyl ligands

The reaction of dimethyltin dichloride with 1,5-bis(2′-pyridyl)pentane-1,3,5-trione (Htrione) resulted in the formation of the dinuclear complex {[Me2ClSn(μ-trione)SnMe2Cl2]·Htrione} (1) in the solid state. The solid state X-ray determination of the complex {[Me2ClSn(μ-trione)SnMe2Cl2]·Htrione} (1) revealed that complex 1 contains the simultaneous presence of penta- and hexacoordinated tin(IV) atoms. Notably, trione acts as a bridging ligand through both oxygen and nitrogen donor atoms. While the hexacoordinated tin(IV) atom adopts an octahedral geometry with a trans-[SnMe2] configuration, the pentacoordinated tin(IV) atom exists in a highly distorted trigonal bipyramidal arrangement with equatorial methyl groups. It is also important to note that there is a free Htrione molecule as a co-crystal in the di-enol form. The complexes [SnMe2Cl(tpyCl)]+[SnMe2Cl3]− (2), [SnMe2Cl(tpyOH)]+Cl− (3) and [SnMe2Cl(tpySH)]+2(SnMe2Cl3)−Cl− (4) were also prepared from the reaction of SnMe2Cl2 with 4′-functionalized 2,2′:6′,2″-terpyridines (tpyX), where X = Cl, O, S. It is important to note that the formation of the anion depends upon the nature of 4′-substituted terpyridyl ligand. The resulting products have been fully characterized by IR, elemental analysis and multinuclear (1H, 13C, 119Sn) NMR spectroscopy. The X-ray crystal structure determination of [SnMe2Cl(tpyCl)]+[SnMe2Cl3]− reveals that the [SnMe2Cl(tpyCl)]+ moiety adopts an octahedral geometry about the tin atom with a trans configuration of the methyl ligands. In the [SnMe2Cl3]− moiety, the tin(IV) atom exists in a trigonal bipyramidal geometry with equatorial methyl groups.

Graphical abstractThe reaction of dimethyltin dichloride with the substituted pyridyl ligand of 1,5-bis(2′-pyridyl)pentane-1,3,5-trione (Htrione) results in the formation of the binuclear diorganotin(IV) complex {[Me2ClSn(μ-trione)SnMe2Cl2]·Htrione}, having penta- and hexacoordinated tin(IV) atoms. In addition, dimethyltin dichloride reacts with 4′-functionalized 2,2′:6′,2″-terpyridine to yield [SnMe2Cl(tpyCl)]+[SnMe2Cl3]−, [SnMe2Cl(tpyOH)]+Cl− and [SnMe2Cl(tpySH)]+2(SnMe2Cl3)−Cl−. The crystal structures of [Me2ClSn(μ-trione)SnMe2Cl2]·Htrione and [SnMe2Cl(tpyCl)]+[SnMe2Cl3]− are reported.Figure optionsDownload full-size imageDownload as PowerPoint slide