Gorga J C, Hazzard J H, Caughey W S
Arch Biochem Biophys. 1985 Aug 1;240(2):734-46. doi: 10.1016/0003-9861(85)90082-7.
The effects of the medium on the infrared spectrum of nitrous oxide (N2O) were determined in the antisymmetric stretch region near 2200 cm-1 for solutions of N2O in 38 different solvents at 25 degrees C. The solvents were chosen to reflect the variety of environments potentially available in sites occupied by N2O in nerve and other tissue. Band parameters of overlapping fundamental and hot bands were obtained with deconvolution techniques. Differences in solvent molecule structure had marked effects on both the frequency and the shape of the infrared bands. The fundamental band frequency (v3) ranged from 2215 cm-1 for carbon disulfide to 2230 cm-1 for water. Among the alcohols, v3 increased nearly linearly with increasing dielectric constant. However, solvent parameters that reflect bulk properties of the solvent did not correlate well with v3 over the entire range of solvents studied. Rather short-range specific solute-solvent molecular interactions appear particularly important. In general, v3 increases with the strength and number of dipoles in adjacent solvent molecules interacting with the vibrating dipole of N2O. Half-bandwidths (delta v1/2) ranged from 7.4 cm-1 for carbon tetrachloride to 14.4 cm-1 for hexane. Variations in bandwidth did not correlate in any direct way with solvent polarity, but delta v1/2 did increase with an increase in the conformational flexibility of the solvent molecule, which results in a greater diversity in the immediate environment about the N2O molecules. The observed sensitivity of the N2O infrared band parameters to changes in solvation environment and the appearance of the antisymmetric stretch band at a frequency within a window of relatively low-energy absorption by water makes infrared spectroscopy potentially useful for the characterization of the sites occupied by the anesthetic molecules within lipid, protein, and aqueous components of intact tissue.
在25摄氏度下，针对一氧化二氮（N₂O）在38种不同溶剂中的溶液，测定了介质对其在2200 cm⁻¹附近反对称伸缩区域红外光谱的影响。选择这些溶剂是为了反映N₂O在神经和其他组织中占据的位点可能存在的各种环境。通过去卷积技术获得了重叠基频带和热频带的谱带参数。溶剂分子结构的差异对红外谱带的频率和形状都有显著影响。基频带频率（v₃）范围从二硫化碳的2215 cm⁻¹到水的2230 cm⁻¹。在醇类中，v₃随介电常数的增加几乎呈线性增加。然而，反映溶剂整体性质的溶剂参数在所研究的整个溶剂范围内与v₃的相关性并不好。相当短程的特定溶质 - 溶剂分子相互作用显得尤为重要。一般来说，v₃随着与N₂O振动偶极相互作用的相邻溶剂分子中偶极的强度和数量增加而增加。半高宽（δv₁/₂）范围从四氯化碳的7.4 cm⁻¹到己烷的14.4 cm⁻¹。带宽的变化与溶剂极性没有任何直接关联，但δv₁/₂确实随着溶剂分子构象灵活性的增加而增加，这导致N₂O分子周围紧邻环境有更大的多样性。观察到的N₂O红外谱带参数对溶剂化环境变化的敏感性以及反对称伸缩带在水的相对低能量吸收窗口内的频率出现，使得红外光谱法有可能用于表征完整组织的脂质、蛋白质和水性成分中麻醉分子所占据的位点。
