Department of Chemistry, Indian Institute of Technology Jodhpur, Jodhpur, Rajasthan 342037, India.
MRI-MRS Centre and Department of Chemistry, Indian Institute of Technology Madras, Tamil Nadu 600036, India.
Phys Chem Chem Phys. 2021 Jul 14;23(27):14564-14568. doi: 10.1039/d1cp01531a.
The present study aims to establish a simple approach involving multi-field multinuclear longitudinal relaxation (R1) analysis of the solvents to decipher solute-solvent interactions during the solvation of model carbohydrates in aqueous trifluoroethanol (TFE) co-solvent systems (TFE:D2O). The behavior of D2O and TFE is monitored around β-CD (β-cyclodextrin) and glucose through R1D (2H) and R1F (19F), respectively. Correlation times (τc) are estimated for D2O and TFE for various % (v/v) compositions of TFE:D2O mixtures. The differential trends of the R1 or τc ratio for D2O and TFE (in the presence and absence of carbohydrates) revealed that both β-CD and glucose undergo selective solvation by TFE in comparison to D2O. Owing to its encapsulation properties, β-CD exhibited a comparatively higher tendency to undergo solvation by TFE than glucose. The maximum transfer of solute bound water to bulk solvent appears in the 20-30% (v/v) TFE range. The current approach emerges as being straightforward in contrast to traditional methods that primarily focus on solute behavior to unravel the preferential solvation dynamics.
本研究旨在建立一种简单的方法，涉及多场多核纵向弛豫（R1）分析溶剂，以在模型碳水化合物在水三氟乙醇（TFE）共溶剂体系（TFE：D2O）中的溶解过程中破译溶剂-溶质相互作用。通过 R1D（2H）和 R1F（19F）分别监测 D2O 和 TFE 在β-CD（β-环糊精）和葡萄糖周围的行为。对于不同体积%（v/v）的 TFE：D2O 混合物，估算了 D2O 和 TFE 的相关时间（τc）。对于 D2O 和 TFE（存在和不存在碳水化合物的情况下）的 R1 或 τc 比的差异趋势表明，与 D2O 相比，β-CD 和葡萄糖都通过 TFE 进行选择性溶解。由于其包合特性，β-CD 比葡萄糖表现出更高的被 TFE 溶解的趋势。溶质结合水向体相溶剂的最大转移出现在 20-30%（v/v）TFE 范围内。与主要关注溶质行为以揭示优先溶解动力学的传统方法相比，当前方法更为直接。
