S-33 NMR-SPECTROSCOPY - 2 - SUBSTITUENT EFFECTS ON S-33 CHEMICAL-SHIFTS AND NUCLEAR-QUADRUPOLE COUPLING-CONSTANTS IN 3-SUBSTITUTED AND 4-SUBSTITUTED BENZENESULFONATES - CORRELATION BETWEEN CHEMICAL-SHIFTS AND NUCLEAR-QUADRUPOLE COUPLING-CONSTANTS

Substituent effects on S-33 NMR parameters in 3-XC6H4SO3Na (X = NO2, N H3+, CF3, SO3-, OH, H, CH3, NH2, and O-) have been studied. The result s obtained confirm that S-33 chemical shifts and line widths depend up on the electronic properties of substituents present on the aromatic r ing. The trends observed are consistent with the behavior found for pr eviously reported 4-substituted benzenesulfonates, whose list has been now enlarged to include ionic substituents (O-, NH3+, NH(CH3)(2)(+), SO3-). Dual substituent parameter analysis of S-33 nuclear quadrupole coupling constants using charged and uncharged substituents has been p erformed. A linear relationship between S-33 chemical shifts and nucle ar quadrupole coupling constants demonstrates that in 3- and 4-substit uted benzenesulfonates substituents affect S-33 NMR parameters in the same way, probably by expansion or contraction of p valence shell elec trons around the sulfur nucleus. O-17 NMR data suggest that sulfur d o rbitals are little effective in transmitting substituent effects.