Nuclear spin–spin coupling between directly bound tin atoms studied by a novel form of INDOR spectroscopy

Abstract

Heteronuclear magnetic double-resonance experiments have been used to determine the signs and magnitudes of ¹J(¹¹⁹Sn¹¹⁹Sn) and other coupling constants in Li{Sn(SnMe₃)₃·3thf, [Fe(η-C₅H₅){P(OPh)₃}₂{Sn(SnMe₃)₃}], and SnMe₂(SnMe₃)₂. Values of ca. –5000 Hz are found in the first of these compounds, and the results indicate that in general tin–tin coupling constants are determined mainly by changes in β_SnSn, the s-overlap integral for the Sn–Sn bond, brought about by changes in the substituents at the tin atoms. A new double-resonance method for recording the spectra of species in low abundance is also described.