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摘要
In order to explore the hydrogen bonding interactions between resorufin anion (denoted as Res(-) in this paper) and water molecules, we have calculated the geometric structures as well as the total energies of the various hydrogen-bonded Res(-)-water complexes composed based on the atomic charges obtained from the NBO analysis. We found that there are four sites (O1-3, N-1) within the Res(-) molecule through which intermolecular hydrogen bonds can be formed with water molecule. Furthermore, by comparing the hydrogen bond lengths and the relative energies of the four singly hydrogen-bonded complexes Res(-)-H2O, we found that hydrogen bonds formed at the two carbonyl oxygen atoms (O-2 and O-3) are stronger than those formed at heteroatom O-1 and N-1 which can be reasonably predicted by the highest negative charge localized on the two former atoms. Moreover, as the number of the water molecules hydrogen-bonded to the Res(-) increases, the hydrogen-bonded complex Res(-)-water becomes more stable although the strength of each hydrogen bond decreases. In addition, the electronic spectra of the various hydrogen-bonded Res(-)-water complexes as well as the Res(-) monomer are also calculated. We found that, compared with that of the Res(-) monomer, the excitation spectra of the hydrogen-bonded Res(-)-water complexes are mostly blue-shifted in the S-2 and S-3 states while they are all red-shifted in the higher excited states, especially in states S-10, S-11 and S-12. According to the relationship between electronic spectral shifts and electronic excited-state hydrogen-bonding dynamics first clarified by Zhao and coworkers [51], we demonstrate that, for all the hydrogen-bonded Res(-)-water complexes, most of the hydrogen bonds are weakened in the S-2 and S-3 states while they are all strengthened in excited states S-10, S-11 and S-12.
- 出版日期2011-9-1
- 单位中北大学
