Factors influencing the 17O quadrupole coupling constant in bridging oxygen environments

Ab initio calculations were performed on the series of clusters [(OH)(3)M-O-M(OH)(3)](-2) where M = B, Al, and Ga, (OH)(3)M-O-M(OH)(3) where M = C, Si, and Ge, (OH)(2)OM-O-MO(OH)(2) where M = P and As, and (OH)O2M-O-MO2(OH) where M = S and Se. These clusters were constructed to model the effect of changing the coordinating cation and coordinating cation-oxygen distances on the bridging oxygen O-17 quadrupole coupling constant. For all clusters studied, we observed a general trend that the magnitude of C-q increases linearly with increasing cation-oxygen bond distance and cation group number, suggesting that group number and cation-bridging oxygen distance can serve as a better predictor of the bridging oxygen quadrupole coupling constant than electronegativity differences. (C) 2000 Elsevier Science B.V. All rights reserved.