Theoretical Study of³¹P NMR Chemical Shifts for Organophosphorus Esters, Their Anions and O,O-Dimethylthiophosphorate Anion with Metal Complexes

In rationalizing such results one of the guidingprinciples that has come through theoretical and experi-mental studies is the concept of electronegativity, i.e. thatincrease in electron density of an atomic nucleus enhancesits shielding, resulting in an upfield chemical shift. However,excepting triesters (Table 1) the