FIVE-COORDINATE COMPLEXES OF 2,2-DIBUTYL-1,3,2-DIOXASTANNOLANS

Article abstract of DOI:10.1016/0022-328X(83)89502-3

2,2-Dibutyl-1,3,2-dioxastannolans, Bu2Sn(OCR2)2, unlike the dioxastannanans, Bu2Sn(OCR2)2CR2, or the acyclic dialkoxides, Bu2Sn(OR)2, react with ligands L, such as pyridine, dimethyl formamide, dimethyl sulphoxide, sulpholane, and tetrahydrofuran to form a series of solid complexes, Bu2Sn(OCR2)2L.Under reduced pressure, the ligands, L, are lost, and the dioxastannolans are regenerated.Measurements of IR, 1H and 119Sn NMR, and Moessbauer spectra, and of molecular weights in solution, imply that the complexes have a trigonal bipyramidal configuration, with equatorial butyl groups, apical ligand L, and the dioxastannolan ring bridging apical and equatorial positions.It is suggested that the relative stability of these complexes results from minimisation of angle strain in the 5-membered ring.