Magic-size clusters (MSCs) are molecular materials with unique properties at the border between molecules and solids, providing important insights into the nanocrystal formation process. However, the synthesis of multicomponent alloy MSCs in a single-ensemble form remains challenging due to their tiny size and difficult doping control. Herein, for the first time, we successfully synthesized alloy ZnxCd13−xSe13 MSCs (x = 1–12) with a unique sharp absorption peak at 352 nm by cation exchange between Cd2+ ions and pre-synthesized (ZnSe)13 MSCs in a diamine solution at room temperature. The experimental results show that the use of diamines is crucial to the formation of stable ZnxCd13−xSe13 MSCs, which may be attributed to two amine groups that can coordinate to the surface of MSCs simultaneously. Limited by the robust interaction between diamine ligands and MSCs, the partial cation exchange results in the formation of alloy ZnxCd13−xSe13 MSCs. In contrast, complete cation exchange occurs in a monoamine solution, giving (CdSe)34 MSCs. Besides, a lower reaction temperature and a higher concentration of diamine favor the formation of ZnxCd13−xSe13 MSCs. Our study provides an important basis for further understanding of the transformation of MSCs and a new approach to the controllable synthesis of alloyed MSCs.
The structure-activity relationship of eleven diamines and MEA was investigated in order to provide guidance for the selection of the potential CO 2 capture absorbent. The effects of methyl, ethyl, hydroxyl groups, and distance between N groups in molecular structures were evaluated experimentally by using the rapid fast screening method and computed by Gaussian 09. Experimental results revealed that the proper number of methyl groups and ethyl groups on N atom could improve the absorption rate as well as the cyclic CO 2 capacity, and the addition of a hydroxyl group actually achieved a lower energy requirement (i.e. cyclic CO 2 capacity) for solvent regeneration with the decreasing stability of carbamate. In addition, the diamine with a hydroxyl group is more favorable for good stability in regeneration process, which addresses the problem of solvent loss in the application of diamines. Chain length extension from C 2 to C 3 can result in the poorer stability of the carbamate and lower energy requirement for amine regeneration. Thus, the lowest energy consumption (i.e. CO 2 cyclic capacity) was then achieved by aqueous 2-((2-aminoethyl)amino)ethanol (AEEA) solution, presenting it can be considered as an alternative or a potential absorbent for post-combustion CO 2 capture. Furthermore, the relative free energies of the tested diamines were computed by the Gaussian software for validating the stability of the carbamate formation , the order of which is in accordance with the order of the cyclic CO 2 capacity for all tested amines, indicating the experimental conclusion can be reliable.
Ruru Chen,Cheng Zhu,Mingzhou Hu,Lian Zhou,Hui Yang,Hailing Zheng,Yang Zhou,Zhiwen Hu,Zhiqin Peng,Bing Wang
Achieving efficient identification of silk protein requires highly sensitive analytical techniques and favorable extraction methods , which is of great significance to the research of ancient silk, especially for the controversial issue of the silk origin. In this paper, proteomics and western blot were proposed to analyze the silk proteins of Bombyx mori ( B. mori ) and Antheraea pernyi ( A. pernyi ) dissolved by different methods. First, the differences in secondary structure were detected via spectroscopy . LC-MS/MS was then employed to characterize the peptides of silk proteins precisely. LiBr solution exhibited outstanding dissolution effect on B. mori cocoon, with 87 proteins detected; while copper-ethylenediamine solution (CED) was more appropriate for A. pernyi cocoon, and 16 proteins were identified in A. pernyi -CED. In addition to fibroin and sericin , abundant seroins, enzymes , protease inhibitors , other functional proteins and uncharacterized proteins were detected. Based on the LC-MS/MS data, diagnostic antibodies for the two species were prepared, and fibroin was successfully identified by western blot assay because both dissolution methods were gentle and did not destroy the antigenic epitopes in the protein molecule. Owing to their good specificity and high sensitivity, these diagnostic antibodies have good application prospects in immunoassays of different silk species. Significance This study presents the comprehensive analysis on silk identification of proteins from B. mori and A. pernyi extracted by different methods via the proteomic and immunology as well as the conventional approaches. Great coverage of two cocoon proteomes was accomplished, which demonstrated the outstanding difference in components and abundance. Based on the proteomics analysis, the diagnostic antibodies against two species were prepared and identified the corresponding fibroin successfully in the completed protein mixtures. To our knowledge, the proteomic and immunology procedures with high efficiency, sensitivity and specificity are novel analysis on the silk identification and has great potential in the field of ancient silk detection.
危险品化学品经营许可证（带存储）