VIBRATIONAL SPECTRUM AND TORSIONAL POTENTIAL OF 2-METHOXY-3-METHYL-1,4-BENZOQUINONE
VIBRATIONAL SPECTRUM AND TORSIONAL POTENTIAL OF 2-METHOXY-3-METHYL-1,4-BENZOQUINONE
复制标题
2-甲氧基-3-甲基-1,4-苯醌的振动谱和扭转势
DOI：
10.1021/jp984800w
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发表时间：
1999
影响因子：
3.3
通讯作者：
J. Breton
中科院分区：
文献类型：
--
作者：
M. Nonella;C. Boullais;C. Mioskowski;E. Nabedryk;J. Breton
用密度泛函方法计算了2-甲氧基-3-甲基-1，4-苯醌的稳定构象和振动光谱.两个稳定的构象已被发现，不同的振动光谱。虽然计算的红外光谱的两种构象不同的几种模式，一个明确的分配实验上可用的频带的两种构象之一是困难的。蛋白质-发色团相互作用已经通过模拟醌-H2O、醌-Li+和醌-N 配合物与水的络合作用已经显著影响了两种构象的相对能量和甲氧基的甲基部分的旋转的扭转势垒。在完全优化的醌-水络合物中，CO和CC伸缩模区域中的振动模式通过络合作用受到影响。与带正电荷的反离子络合显着地改变了系统的能量，并将前最低能量构象改变为鞍点。振动频率比与水分子络合时受到更强烈的影响。
Stable conformations and vibrational spectra of 2-methoxy-3-methyl-1,4-benzoquinone were calculated using density functional methods. Two stable conformers have been found which differ in their vibrational spectrum. Although the calculated infrared spectra of the two conformers differ with respect to several modes, a definite assignment of the experimentally available bands to one of the two conformers is difficult. Protein−chromophore interactions have been studied by modeling quinone−H2O, quinone−Li+, and quinone−N complexes. A complexation with water already considerably affects the relative energies of the two conformers and the torsional barrier for the rotation of the methyl part of the methoxy group. In fully optimized quinone−water complexes, vibrational modes in the CO and CC stretching mode region are affected through the complexation. Complexation with a positively charged counter ion dramatically changes the energetics of the system and changes the former minimum energy conformation into a saddle point. Vibrational frequencies are more strongly affected than upon complexation with a water molecule.