INTRAMOLECULAR COORDINATION IN ORGANOTIN CHEMISTRY

This chapter overviews organotin compounds containing C,Y-chelating ligands particularly, (1) structures in the solid state, (2) fluxional behavior in solution, and (3) stereochemical aspects. Attention is also given to the enhanced reactivity of tin–carbon bonds in tetraorganotin compounds as a result of intramolecular coordination. The first example of an organotin compound having C,Y-chelating ligands, i.e., bis [1, 2-bis(ethoxycarbonyl)ethyl]tin dibromide, for which the structure in the solid state was unambiguously established by an X-ray crystal structure determination. By using the steric and electronic properties of C,Y-chelating ligands, organometallic compounds that have interesting properties and special reactivities can be isolated. Special features of some of these compounds are (1) stabilization of organometallic compounds in which the metal has an unusual oxidation number, e.g., Fe(II1), Co(I1), and Ni(II1); (2) the trapping of organometallic species that are supposed to be intermediates in reactions, e.g., organoplatinum compounds in which a di-iodine molecule is coordinated end-on to platinum as a first step in oxidative-addition reactions; (3) the use of a novel organonickel compound as a catalyst in the selective Karasch addition of polyhaloalkanes to olefines; and (4) the unexpected reactivity of organocopper compounds toward acetylenes. © 1993, Academic Press Inc.