Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, Virginia 22807, United States.
Department of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia.
J Phys Chem A. 2023 Feb 2;127(4):946-955. doi: 10.1021/acs.jpca.2c08327. Epub 2023 Jan 20.
Mid-infrared spectra of methanol and methanol-water clusters have been investigated in the symmetric CD stretching band of CDOH and CDOD. We find that the position of this band provides a useful signature of the general type of hydrogen-bonded cluster it is associated with. Our results are consistent with those previously reported in the OH stretching region (Sulaiman, M. I.; Yang, S.; Ellis, A. M. 2017, 121, 771-776) in that methanol clusters from the trimer to the pentamer are cyclic and that mixed clusters with one water molecule (and at least two methanol molecules) are also cyclic. We additionally provide evidence that the methanol trimer adopts a chair-like structure (as opposed to bowl-like), that mixed clusters with a larger number of water molecules are also cyclic, and that branched methanol clusters contribute to the depletion signal in larger methanol clusters. We performed double-hybrid DFT calculations which support these interpretations.
甲醇和甲醇-水团簇的中红外光谱在 CDOH 和 CDOD 的对称 CD 伸缩带中进行了研究。我们发现，该带的位置提供了与其相关的氢键团簇的一般类型的有用特征。我们的结果与之前在 OH 伸缩区域（Sulaiman，MI；Yang，S.；Ellis，AM 2017，121，771-776）中报道的结果一致，即三聚体到五聚体的甲醇团簇是环状的，并且具有一个水分子（和至少两个甲醇分子）的混合团簇也是环状的。我们还提供了证据表明甲醇三聚体采用椅式结构（而不是碗状），具有更多水分子的混合团簇也是环状的，并且支化甲醇团簇导致在较大甲醇团簇中耗尽信号。我们进行了双杂交 DFT 计算，这些计算支持了这些解释。
