Correlation analysis of infrared, 31P NMR, and theoretical data of derivatives of phosphoric and thiophosphoric acids

Infrared and P-31 NMR spectra were measured for thirty-seven trisubstituted derivatives of phosphoric acids and potassium salts of disubstituted derivatives of thiophosphoric acids. Both, the IR <(nu)over tilde>(nu(P=O)) and NMR delta(P-31) data correlate significantly mutually as well as with inductive sigma* substituent constants. The P=O bond orders and O charge densities calculated by AM1 approach provide also satisfactory linear correlations with infrared data. The considerably high slope of the at Delta<($nu)over tilde>(nu(P=O)) vs, sigma*(R) correlation equation shows a marked substituent sensitivity of the phosphoryl group. From the results of the correlation analysis the value sigma* = 1.53 has been determined for sulfide anionic substituent. which is comparable to the electron-acceptor effect of alkoxy groups. The infrared and P-31 NMR. data provide also satisfactory linear correlations with the P=O bond orders, O and P charge densities, respectively.