Ohno Keiichi, Shimoaka Takafumi, Akai Nobuyuki, Katsumoto Yukiteru
Graduate School of Science, Hiroshima University, 1-3-1 Kagami-yama Higashi-Hiroshima 739-8526, Japan.
J Phys Chem A. 2008 Aug 14;112(32):7342-8. doi: 10.1021/jp800995m. Epub 2008 Jul 18.
The OH stretching (nu(OH)) band of methanol observed in condensed phase has been analyzed in terms of hydrogen-bonding patterns. Quantum chemical calculations for methanol clusters have revealed that broadening of the nu(OH) envelope is reasonably reproduced by considering nearest and next-nearest neighbor interactions through hydrogen bonding. Because the hydrogen bond formed between donor (D) and acceptor (A) is cooperatively strengthened or weakened by a newly formed hydrogen bond at D or A, we have proposed the following notation for hydrogen-bonding patterns of monohydric alcohols: a(D)DAd(A)a(A), where a is the number of protons accepted by D (a(D)) or A (a(A)), and d(A) is the number of protons donated by A. The indicator of the hydrogen-bond strength, which is given by M(OH) = a(D) + d(A) - a(A), is correlated well with the nu(OH) wavenumber of the methanol molecule D participating in the a(D)DAd(A)a(A) pattern. The correlation between M(OH) and the hydrogen-bonding energy of the a(D)DAd(A)a(A) pattern has also been deduced from the calculation results for the clusters. The nu(OH) bands of methanol measured in the CCl4 solution and pure liquid have been successfully analyzed by the method proposed here.
已根据氢键模式对凝聚相中观察到的甲醇的 OH 伸缩振动（ν(OH)）带进行了分析。甲醇团簇的量子化学计算表明，通过考虑氢键作用下最近邻和次近邻相互作用，可以合理再现 ν(OH) 包络的展宽。由于供体（D）和受体（A）之间形成的氢键会因 D 或 A 处新形成的氢键而协同增强或减弱，因此我们提出了以下一元醇氢键模式的表示法：a(D)DAd(A)a(A)，其中 a 是 D（a(D)）或 A（a(A)）接受的质子数，d(A) 是 A 给出的质子数。氢键强度指标由 M(OH) = a(D) + d(A) - a(A) 给出，它与参与 a(D)DAd(A)a(A) 模式的甲醇分子 D 的 ν(OH) 波数具有良好的相关性。M(OH) 与 a(D)DAd(A)a(A) 模式的氢键能之间的相关性也已从团簇的计算结果中推导得出。本文提出的方法已成功分析了在 CCl4 溶液和纯液体中测量的甲醇的 ν(OH) 带。
