超快二维红外化学交换光谱观察到分子位点间的氢键迁移。
Hydrogen bond migration between molecular sites observed with ultrafast 2D IR chemical exchange spectroscopy.
机构信息
Department of Chemistry, Stanford University, Stanford, California 94305, USA.
出版信息
J Phys Chem B. 2010 Feb 25;114(7):2383-9. doi: 10.1021/jp911452z.
Hydrogen-bonded complexes between phenol and phenylacetylene are studied using ultrafast two-dimensional infrared (2D IR) chemical exchange spectroscopy. Phenylacetylene has two possible pi hydrogen bonding acceptor sites (phenyl or acetylene) that compete for hydrogen bond donors in solution at room temperature. The OD stretch frequency of deuterated phenol is sensitive to which acceptor site it is bound. The appearance of off-diagonal peaks between the two vibrational frequencies in the 2D IR spectrum reports on the exchange process between the two competitive hydrogen-bonding sites of phenol-phenylacetylene complexes in the neat phenylacetylene solvent. The chemical exchange process occurs in approximately 5 ps and is assigned to direct hydrogen bond migration along the phenylacetylene molecule. Other nonmigration mechanisms are ruled out by performing 2D IR experiments on phenol dissolved in the phenylacetylene/carbon tetrachloride mixed solvent. The observation of direct hydrogen bond migration can have implications for macromolecular systems.
使用超快二维红外（2D IR）化学交换光谱研究了苯酚和苯乙炔之间的氢键复合物。苯乙炔有两个可能的π氢键受体位点（苯基或乙炔基），在室温下的溶液中竞争氢键供体。氘代苯酚的 OD 伸缩频率对其结合的受体位点敏感。在 2D IR 光谱中两个振动频率之间的非对角峰的出现报告了在纯苯乙炔溶剂中苯酚-苯乙炔复合物的两个竞争氢键位点之间的交换过程。化学交换过程发生在大约 5 ps 内，被分配为直接沿着苯乙炔分子的氢键迁移。通过在苯酚溶解于苯乙炔/四氯化碳混合溶剂中进行 2D IR 实验，排除了其他非迁移机制。直接氢键迁移的观察结果可能对大分子系统有影响。
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