拉曼光谱法研究1,3-二甲基脲溶液中的相互作用

尿素类化合物在生命科学领域中有非常重要的作用，其独特的化学结构可与水等其他氢键给体材料形成氢键。氢键是生命分子体系中较常见和重要的分子间弱的相互作用，振动光谱方法为分子间氢键相互作用的研究提供有力的测量手段，其中拉曼光谱为研究水溶液中氢键形成和变化规律提供了可能。测得了1，3-二甲基脲(DMU)晶体的拉曼光谱，利用密度泛函理论(DFT)在B3LYP/6-311G**水平上对气态单体DMU进行结构的优化，并结合文献对拉曼光谱的谱线进行了归属认证。然后测得了1，3-DMU与水二元体系的拉曼光谱。相比与DMU晶体，当DMU分子溶于水后，水-DMU氢键相互作用将取代DMU-DMU分子间相互作用，导致氮原子杂化方式由sp2向sp3杂化转变。由此溶解过程中DMU分子的骨架从平面结构变成了非平面结构。

Investigation of the Interaction between 1,3-Dimethylurea and Solvent by Raman Methods

Urea family plays significant role in the bio-science area. Because of the unique frame, they can form Hydrogen bond with water as well as other substance. Hydrogen bonds are normal weak interactions in the system of bio-molecules. A Raman spectrum is the most powerful method to obscure the Hydrogen bond interaction between molecules. Initially, we measure the Raman spectra of DMU crystal, and then use density function theory with a B3LYP/6-311G** basis set to optimize the geometry structure and calculate the vibrational frequency of gas phase DMU, which assigns the Raman pecks. Then, measure the solvent. When dissolving DMU in water, the interaction between DMU-DMU will replaced by the interaction between water-DMU. The orbital hybridization of nitrogen atoms changes from the solid-state the sp2 orbital hybridization to sp3. So, the frame of this molecule goes from in-planet to out of plant during this process.