Mary M Briget, Sasirekha V, Ramakrishnan V
Laser Laboratory, Department of Microprocessor and Computer, School of Physics, Madurai Kamaraj University, Madurai 625021, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Nov;65(3-4):955-63. doi: 10.1016/j.saa.2006.01.043. Epub 2006 May 8.
A comparative study of infrared and Raman spectra of DL-valine DL-valinium picrate (DL-VVP) and DL-methionine DL-methioninium picrate (DL-MMP) at the room temperature in 4000-50 cm(-1) range helps to determine the effect of hydrogen bonds in these crystals. The existence of the zwitterion and the protonated form in both the crystals has been observed. In DL-MMP, the methionine and the methioninium residues form a dimer through a strong hydrogen bond between them in the crystal. The characteristic bands due to gem-methyl group are observed in the case of DL-VVP. Factor group analysis has been made and the numbers of vibrational modes have been calculated. The tentative assignments of the observed bands are given. The picrate group forms the anion in both the crystals and it is unaffected by the presence of the cations.
室温下在4000 - 50 cm⁻¹范围内对DL-缬氨酸苦味酸DL-缬铵盐（DL-VVP）和DL-蛋氨酸苦味酸DL-蛋铵盐（DL-MMP）的红外光谱和拉曼光谱进行比较研究，有助于确定这些晶体中氢键的作用。已观察到两种晶体中两性离子和质子化形式的存在。在DL-MMP中，蛋氨酸和蛋铵盐残基在晶体中通过它们之间的强氢键形成二聚体。在DL-VVP的情况下观察到了由于偕甲基基团产生的特征谱带。进行了因子群分析并计算了振动模式的数量。给出了观察到的谱带的初步归属。苦味酸根在两种晶体中都形成阴离子，并且不受阳离子存在的影响。
