Intramolecular coordination at phosphorus: donor-acceptor interaction in three- and four-coordinated phosphorus compounds

Abstract

The phosphorus derivatives P(X)(O 2C 6H 4−1,2) 2[C 6H 4(CH 2NMe 2) 2−2] ( 9–11) undergo ready extension of coordination by N → P intramolecular donor-acceptor interaction as shown by 31P NMR and dynamic 1H NMR spectroscopy. This extension of coordination does not occur with P(X)(OEt) 2[C 6H 4(CH 2NMe 2) 2−2] ( 7 and 8). The ΔG ≡ of pseudo-rotation was calculated by dynamic 1H NMR spectroscopy to be 57–58 kJ mol −1 for the three compounds P(X)O 2C 6 4−1,2) 2[C 10H 6(NMe 2−8)] ( 19–21).