Li Jiongzhao, Cao Weicheng, Shu Yufei, Zhang Haibing, Qian Xudong, Kong Xueqian, Wang Linjun, Peng Xiaogang
Zhejiang Key Laboratory of Excited-State Materials, Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Natl Sci Rev. 2021 Aug 4;9(2):nwab138. doi: 10.1093/nsr/nwab138. eCollection 2022 Feb.
High-quality colloidal nanocrystals are commonly synthesized in hydrocarbon solvents with alkanoates as the most common organic ligand. Water molecules with an approximately equal number of surface alkanoate ligands are identified at the inorganic-organic interface for all types of colloidal nanocrystals studied, and investigated quantitatively using CdSe nanocrystals as the model system. Carboxylate ligands are coordinated to the surface metal ions and the first monolayer of water molecules is found to bond to the carboxylate groups of alkanoate ligands through hydrogen bonds. Additional monolayer(s) of water molecules can further be adsorbed through hydrogen bonds to the first monolayer of water molecules. The nearly ideal environment for hydrogen bonding at the inorganic-organic interface of alkanoate-coated nanocrystals helps to rapidly and stably enrich the interface-bonded water molecules, most of which are difficult to remove through vacuum treatment, thermal annealing and chemical drying. The water-enriched structure of the inorganic-organic interface of high-quality colloidal nanocrystals must be taken into account in order to understand the synthesis, processing and properties of these novel materials.
高质量的胶体纳米晶体通常在烃类溶剂中合成，链烷酸酯是最常见的有机配体。对于所研究的所有类型的胶体纳米晶体，在无机-有机界面处都发现了表面链烷酸酯配体数量大致相等的水分子，并以CdSe纳米晶体作为模型系统进行了定量研究。羧酸酯配体与表面金属离子配位，并且发现第一层水分子通过氢键与链烷酸酯配体的羧酸根基团结合。额外的单层水分子可以通过氢键进一步吸附到第一层水分子上。在链烷酸酯包覆的纳米晶体的无机-有机界面处，近乎理想的氢键环境有助于快速且稳定地富集界面结合的水分子，其中大部分水分子难以通过真空处理、热退火和化学干燥去除。为了理解这些新型材料的合成、加工和性质，必须考虑高质量胶体纳米晶体无机-有机界面的富水结构。
