The chemistry of heteroarylphosphorus compounds. Part 15. Phosphorus-31 nuclear magnetic resonance studies of the donor properties of heteroarylphosphines towards selenium and platinum(II)

The donor properties of a series of heteroarylphosphines (bearing 2- and 3-furyl, 2- and 3-thienyl, and 1-methylpyrrol-2-yl groups directly bound to phosphorus) towards selenium and platinum(II) acceptors have been investigated by 31P n.m.r. studies of the one-bond coupling constants 1J(77Se–31P) and 1J(195Pt–31P). It is shown that the respective coupling constants increase as the heteroaryl groups become more electron withdrawing, indicating an increased s character for the phosphorus lone pair. The implications of this for the relative donor properties of the heteroarylphosphines and PPh3 are considered.