Stepwise Assembly of MII7 Clusters Revealed by Mass Spectrometry,EXAFS, and Crystallography |
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| Authors: | Hong‐Xu Na Pei‐Yu Yang Dr. Zheng Yin Yun‐Hong Wang Li‐Xian Chang Prof. Dr. Rui Si Dr. Mohamedally Kurmoo Prof. Dr. Ming‐Hua Zeng |
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| Affiliation: | 1. Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, P.R. China;2. College of Chemistry and Chemical Engineering, Shaanxi University of Science & Technology, Xi'an, P.R. China;3. Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, P.R. China;4. Institut de Chimie de Strasbourg, CNRS-UMR 7177, Université de Strasbourg, Strasbourg, France;5. College of Chemistry & Chemical Engineering, Hubei University, Wuhan, P.R. China |
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| Abstract: | The square‐planar monomer NiL2 ( Ni1 ), L=2‐ethoxy‐6‐(N‐methyl‐iminomethyl)phenolate, reacts with M(H2O)6(ClO4)2, M=Ni or Co, to form heptanuclear disks [CoxNi7?x(OH)6(L)6](ClO4)2 ? 2 CH3CN ( Co x Ni7?x , x=0–7) and the co‐crystal [CoxNi7?x(OH)6L6][NiL2](ClO4)2 ? 2 CH3CN ( Co x Ni7?x ‐Ni1 ) under ambient conditions. It has proved possible to explore the bottom‐up assembly process of Co x Ni7?x and Co x Ni7?x ‐Ni1 in real time. The final products have been characterized by thermogravimetric analysis, IR, elemental analysis, ICP‐MS, and single‐crystal X‐ray diffraction. Time‐dependent mass spectrometry (MS) revealed the following reaction steps: Ni1→[M2L3]+→[M4(OH)2L4]2+→[M7(OH)6L6]2+. In contrast, the reaction of Ni1 with Zn2+ only reaches halfway, and crystallographic evidence indicates a butterfly structure for [Zn2Ni2(OH)2Cl2] ( Zn2Ni2 ), an intermediate that is difficult to isolate in the above Ni‐Co series. A summation method has been used to analyze the MS of bimetallic clusters with very similar atomic masses, as is the case for Co and Ni. The results provide ample information on the distribution of Co and Ni within each cluster and their statistical distribution within selected crystals. |
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| Keywords: | assembly processes crystal growth EXAFS spectroscopy mass spectrometry mixed-metal clusters |
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