Dimitrova Yordanka
Institute of Organic Chemistry, Bulgarian Academy of Sciences, Bl. 9, 1113 Sofia, Bulgaria.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Jul;67(3-4):586-91. doi: 10.1016/j.saa.2006.07.041. Epub 2006 Aug 18.
The complexes formed by ethene with nitric and nitrous (trans and cis) acids have been investigated by ab initio (SCF and MP2) and B3LYP calculations with 6-311++G(d,p) basis set. Full geometry optimisation has been performed for the complexes studied. The most stable structures of the complexes are established. Bearing in mind the corrected values of the dissociation energy the studied hydrogen-bonded complexes can be ordered as follows: C(2)H(4)...HONO(2)>C(2)H(4)...HONO-trans>C(2)H(4)...HONO-cis. In the complexes the acids act as proton donors forming the pi-type of hydrogen bond with ethene. The predicted changes in the vibrational characteristics (vibrational frequencies and infrared intensities) arising from the hydrogen bonding are in good agreement with the experimentally measured. The predicted frequency shift of the stretching OH vibration in the nitric acid is largest (-210 cm(-1)), followed by the shifts in the trans-HONO (-141 cm(-1)) and cis-HONO (-109 cm(-1)). The calculations predict an increase of the IR intensity of the stretching O-H vibration in the complexes from 6 to 10 times.
通过使用6-311++G(d,p)基组的从头算（SCF和MP2）以及B3LYP计算，研究了乙烯与硝酸和亚硝酸（反式和顺式）形成的配合物。对所研究的配合物进行了完全几何优化。确定了配合物最稳定的结构。考虑到解离能的校正值，所研究的氢键配合物可按以下顺序排列：C(2)H(4)...HONO(2)>C(2)H(4)...HONO-反式>C(2)H(4)...HONO-顺式。在这些配合物中，酸充当质子供体，与乙烯形成π型氢键。由氢键引起的振动特性（振动频率和红外强度）的预测变化与实验测量结果吻合良好。硝酸中拉伸OH振动的预测频移最大（-210 cm(-1)），其次是反式-HONO（-141 cm(-1)）和顺式-HONO（-109 cm(-1)）中的频移。计算预测配合物中拉伸O-H振动的红外强度增加6到10倍。
