Gurung Anit, Zhang Rui, Wang Lu, G Kuroda Daniel
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, United States.
J Am Chem Soc. 2025 Apr 23;147(16):13251-13257. doi: 10.1021/jacs.4c17870. Epub 2025 Apr 8.
The unconventional supramolecular chemistry between perfluoro--butanol (PFTB), as an acid, and 1-methylimidazole (MIM), as a base, is presented. Supramolecular chemistry occurs in MIM-PFTB mixtures with a base-to-acid molar ratio of 1:2, or higher, and coincides with the formation of strong hydrogen bonds (SHBs) in which the acidic hydrogen atoms are quantum mechanically delocalized. Evidence for the SHB and the hydrogen atom sharing is obtained from IR and H NMR spectroscopies and X-ray crystallography. First-principles simulations incorporating both electronic and nuclear quantum effects verify the presence of the SHBs and demonstrate that the broad IR absorption band centered at 2400 cm and the large downfield H NMR of the complexes are a consequence of the hydrogen atom sharing between the acid and the base. The supramolecular behavior reported for PFTB-MIM has not been previously observed in other monoprotic acid-base mixtures forming either conventional or SHBs. Hence, MIM-PFTB mixtures depart from the behavior typically exhibited by other liquid mixtures, demonstrating that electronic and nuclear quantum effects play an important role in driving the unconventional supramolecular chemistry observed in MIM-PFTB samples.
本文介绍了全氟丁醇（PFTB，作为一种酸）与1-甲基咪唑（MIM，作为一种碱）之间非常规的超分子化学。超分子化学发生在碱与酸的摩尔比为1:2或更高的MIM-PFTB混合物中，并且与强氢键（SHB）的形成同时出现，其中酸性氢原子在量子力学上发生离域。通过红外光谱、核磁共振氢谱和X射线晶体学获得了SHB和氢原子共享的证据。结合电子和核量子效应的第一性原理模拟验证了SHB的存在，并表明以2400 cm为中心的宽红外吸收带以及配合物的大的低场核磁共振氢谱是酸和碱之间氢原子共享的结果。此前在形成常规氢键或强氢键的其他单质子酸碱混合物中尚未观察到PFTB-MIM所报道的超分子行为。因此，MIM-PFTB混合物不同于其他液体混合物通常表现出的行为，这表明电子和核量子效应在驱动MIM-PFTB样品中观察到的非常规超分子化学过程中起着重要作用。
