Oh Young-Ho, Lee So Yeon, Oh Han Bin, Lee Sungyul
Department of Applied Chemistry, Kyung Hee University, 1732, Deogyeong-daero, Giheung-gu, Yongin-si 17104, Republic of Korea.
Department of Chemistry, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul 04107, Republic of Korea.
Molecules. 2025 Apr 11;30(8):1723. doi: 10.3390/molecules30081723.
We study the structures of 24-crown-8/H/diaminopropanol (CR/DAPH) and 24-crown-8/CsF/H/diaminopropanol (CR/CsF/DAPH) non-covalent host-guest complexes in both the gas phase and aqueous solution using the density functional theory (DFT) method. We examine the environment (complexation with CR vs. solvation) around the guest functional groups (ammoium, hydroxyl, and amino) in the CR/DAPH and CR/CsF/DAPH complexes. We find that the gas-phase configurations with the 'naked' hydroxyl/amino devoid of H-bonding with CR or CR/CsF are structurally correlated with the lowest Gibbs free energy conformers in aqueous solution in which the functional groups are solvated off the CR or CR/CsF host. We predict that the latter thermodynamically disadvantageous host-guest configurations would be identified in the gas phase by infrared multiphoton dissociation (IRMPD) spectroscopy, originating from the complexes in aqueous solution. This predicted 'thermodynamic reversal' and 'structural correlation' of the host-guest configurations in the gas phase vs. in solution are discussed in relation to the possibility of obtaining information on host-guest-solvent interactions in the solution phase from the gas-phase host-guest configurations.
我们采用密度泛函理论（DFT）方法，研究了气相和水溶液中24-冠-8/氢离子/二氨基丙醇（CR/DAPH）和24-冠-8/氟化铯/氢离子/二氨基丙醇（CR/CsF/DAPH）非共价主客体配合物的结构。我们考察了CR/DAPH和CR/CsF/DAPH配合物中客体官能团（铵基、羟基和氨基）周围的环境（与CR络合与溶剂化）。我们发现，气相中“裸露”的羟基/氨基与CR或CR/CsF没有氢键作用的构型，在结构上与水溶液中最低吉布斯自由能构象相关，在水溶液中官能团从CR或CR/CsF主体上溶剂化。我们预测，后一种热力学上不利的主客体构型在气相中可通过红外多光子解离（IRMPD）光谱识别，其源于水溶液中的配合物。本文讨论了气相与溶液中主客体构型的这种预测的“热力学反转”和“结构相关性”，以及从气相主客体构型获取溶液相中主客体-溶剂相互作用信息的可能性。
