Magnetic double resonance studies of trimethylstannylphosphines and their complexes

Abstract

The reduced coupling constant ¹K(PSn) has substantial negative values in the compounds (Me₃Sn)_3–nPh_nP (n= 0–2) and increases algebraically to values close to zero in transition metal carbonyl complexes (Me₃Sn)_3–nPh_nPM(CO)₅(M = Cr, MO, or W). This behaviour parallels that of ¹K(PC) in analogous compounds but there is a substantial negative contribution in the tin-containing compounds which is attributed to a larger energy gap between the phosphorus and tin valence atomic orbitals. In contrast with the behaviour of triorganophosphines the phosphorus chemical shifts do not vary linearly with n, and the changes in phosphorus shielding which accompany complex formation are discussed.