Can an OH radical form a strong hydrogen bond? A theoretical comparison with H2O.
In this study, we apply UCCSD/6-31++G** to investigate the ability of an OH radical acting as a hydrogen bond acceptor with HF, HCl, and H(2)O (HO...HX; X=F, Cl, OH) or as a hydrogen bond donor with H(2)O and H(2)S (OH...XH(2); X=O and S). We also replace OH with H(2)O and make a fair comparison between them. Additionally, the counterpoise method (CP) has been used to examine the effect of basis set superposition error (BSSE). Our results reveal that OH is a stronger hydrogen bond donor but a weaker hydrogen bond acceptor than H(2)O. This conclusion is independent of the correction for BSSE and can be rationalized by the NBO analysis, the results of which indicate that OH radical has a lower n(O) and sigma*(O-H) in energy than that of H(2)O.
Lai
Chin-Hung
CH
Department of Chemistry, National Taiwan University, 106, Taipei, Taiwan, Republic of China. chop@ntu.edu.tw
Chou
Pi-Tai
PT
D005609:Free Radicals / Q000737:chemistry; D006860:Hydrogen Bonding; D006878:Hydroxides / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D014867:Water / Q000737:chemistry*
D005609:Free Radicals; D006878:Hydroxides; D014867:Water; C031356:hydroxide ion