Über zinn-haltige heterocyclen : V. Sn-phenyk-substituierte stannocane, Übergänge von tetraedrischer 4-Zu trigonal-bipyramidaler 5-koordination

A complete series of diphenyl and mixed methyl/chlorine/bromine/iodinephenyl substituted oxadithia- and trithiastannocanes has been prepared by reactions between the respective disodium dithiolates and tin dihalides. The ¹³C NMR chemical shifts of these compounds and the coupling constants J(¹¹⁹Sn¹³C) are dependent upon the magnetic anisotropy of the substituents and the bond angles at the tin atom. The crystal structure of 2,2-diphenyl-1,3,6-trithia-2-stannocane has been determined and refined to R = 0.039. The environment of Sn is a monocapped tetrahedron (transannular distance Sn?S 324.6(1) pm). This type of coordination, intermediate between a tetrahedron and a trigonal bipyramid, is discussed quantitatively and compared with a series of analogous compounds. The eight-membered ring has the boat-chair conformation.