MOESSBAUER AND NMR STUDIES OF INTRAMOLECULAR COORDINATION IN THIENYLTETRAORGANOTIN(IV) COMPOUNDS, AND THE X-RAY CRYSTAL STRUCTURE OF >TRI(p-TOLYL)TIN(IV)

Article abstract of DOI:10.1016/0022-328X(87)85004-0

Tetraorganotin(IV) compounds containing the <3-(2-pyridyl)-2-thienyl> group (L), of formula R3SnL (1: R=p-tolyl; 2: R=Ph; 3: R=p-ClC6H4; 4: R=cyclo-C5H9; 5: R=cyclo-C6H11) have been synthesized and their structures examined by 119mSn Moessbauer and NMR (119Sn and 13C modes) spectroscopic techniques, and in the case of compound 1 by X-ray analysis.Compound 1 crystallises in the space group C2/c with a 20.85(1), b 9.521(1), c 26.69(1) Angstroem; β 95.37(3) deg, V 5274(3) Angstroem³; Z=8.Its structure was solved by the heavy-atom method from 4251 observed Mo-K_α data and refined to R=0.068.The coordination environment at tin in the compound is best described as a pseudo-trigonal bipyramid, involving a weak intramolecular Sn-N bond of distance 2.841(7) Angstroem.This view is supported by the observation of partially-resolved Moessbauer spectra for compounds 1-5 (QS 0.57-0.96 mm s^-1) which is not evidenced, on the other hand, for (2-thienyl)SnR3 compounds (7: R=p-tolyl; 8: R=Ph), as well as by similar comparisons of data on 119Sn chemical shifts (-176.3.ppm for 1 relative to -135.5. ppm for 8) and one-bond coupling constants, ¹J(119Sn-13C(1)), where C(1)=ipso-carbon of the aryl group or α-carbon of the cycloalkyl group (647.5 Hz for 1, 726.6 Hz for 2 and 786.2 Hz for 3 relative to 536.9 Hz for 7).