title: Stepwise Assembly of MII7Clusters Revealed by Mass Spectrometry, EXAFS, and Crystallography.
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 (CoxNi7-x, x=0-7) and the co-crystal [CoxNi7-x(OH)6L6][NiL2](ClO4)2⋅2 CH3CN (CoxNi7-x-Ni1) under ambient conditions. It has proved possible to explore the bottom-up assembly process of CoxNi7-xand CoxNi7-x-Ni1in 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 Ni1with 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.
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, 541004, P.R. China.
authors: Hong-Xu
authors: HX
authors: Na
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, 541004, P.R. China.
authors: Pei-Yu
authors: PY
authors: Yang
authors: College of Chemistry and Chemical Engineering, Shaanxi University of Science & Technology, Xi'an, 710021, P.R. China.
authors: Zheng
authors: Z
authors: Yin
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, 541004, P.R. China.
authors: Yun-Hong
authors: YH
authors: Wang
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, 541004, P.R. China.
authors: Li-Xian
authors: LX
authors: Chang
authors: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai, 201204, P.R. China.
authors: Rui
authors: R
authors: Si
authors: Institut de Chimie de Strasbourg, CNRS-UMR 7177, Université de Strasbourg, 67070, Strasbourg, France.
authors: Mohamedally
authors: M
authors: Kurmoo
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, Guangxi Normal University, Guilin, 541004, P.R. China.|College of Chemistry & Chemical Engineering, Hubei University, Wuhan, 430062, P.R. China.
authors: Ming-Hua
authors: MH
authors: Zeng
keywords: EXAFS spectroscopy; assembly processes; crystal growth; mass spectrometry; mixed-metal clusters