Department of Chemistry, Karnatak University, Pavate Nagar, Dharwad 580 003, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Dec 15;84(1):137-43. doi: 10.1016/j.saa.2011.09.021. Epub 2011 Sep 16.
Electronic absorption and fluorescence spectra of mono, di, and tri-nitro benzimidazolones are measured at room temperature (298 K) in nine solvents with different polarities and the observed shifts are compared with benzimidazolone. Ground and excited state electric dipole moments are determined using the solvatochromic method based on the bulk solvent properties, F(1)(ε, n) and F(2)(ε, n). A reasonable agreement is observed between the experimental and ab initio dipole moments. Change in dipole moment is also determined using the solvatochromic method based on the microscopic solvent polarity parameter, (E(T)(N)), which considers the polarization changes due to hydrogen bonding in different solvents. It has been observed that the correlation of the solvatochromic Stokes shifts with the parameter (E(T)(N)), is superior to that derived using bulk solvent polarity functions for all the benzimidazolones reported in the present study. Calculated difference between excited state and ground state dipole moments seems to be a good measure of the effect of nitro group when correlated with (E(T)(N)).
在室温（298 K）下，在九种具有不同极性的溶剂中测量了单、二和三硝基苯并咪唑酮的电子吸收和荧光光谱，并将观察到的位移与苯并咪唑酮进行了比较。使用基于体相溶剂性质的溶剂变色法 F(1)(ε, n) 和 F(2)(ε, n) 确定了基态和激发态电偶极矩。实验和从头算偶极矩之间观察到了合理的一致性。使用基于微观溶剂极性参数 (E(T)(N)) 的溶剂变色法也确定了偶极矩的变化，该参数考虑了氢键在不同溶剂中引起的极化变化。已经观察到，对于本研究中报道的所有苯并咪唑酮，与基于体相溶剂极性函数得出的关系相比，溶剂变色斯托克斯位移与参数 (E(T)(N)) 的相关性更好。当与 (E(T)(N)) 相关联时，激发态和基态偶极矩之间的计算差异似乎是硝基基团影响的一个很好的度量。
