Direct Observation of Bis(dicarbollyl)nickel Conformers in Solution by Fluorescence Spectroscopy: An Approach to Redox-Controlled Metallacarborane Molecular Motors

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• 作者：Alexander V. Safronov ; Natalia I. Shlyakhtina ; Thomas A. Everett ; Monika R. VanGordon ; Yulia V. Sevryugina ; Satish S. Jalisatgi ; M. Frederick Hawthorne
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：October 6, 2014
• 年：2014
• 卷：53
• 期：19
• 页码：10045-10053
• 全文大小：477K
• ISSN：1520-510X

文摘

As a continuation of work on metallacarborane-based molecular motors, the structures of substituted bis(dicarbollyl)nickel complexes in Ni^III and Ni^IV oxidation states were investigated in solution by fluorescence spectroscopy. Symmetrically positioned cage-linked pyrene molecules served as fluorescent probes to enable the observation of mixed meso-trans/dl-gauche (pyrene monomer fluorescence) and dl-cis/dl-gauche (intramolecular pyrene excimer fluorescence with residual monomer fluorescence) cage conformations of the nickelacarboranes in the Ni^III and Ni^IV oxidation states, respectively. The absence of energetically disfavored conformers in solution鈥?i>dl-cis in the case of nickel(III) complexes and meso-trans in the case of nickel(IV)鈥攚as demonstrated based on spectroscopic data and conformer energy calculations in solution. The conformational persistence observed in solution indicates that bis(dicarbollyl)nickel complexes may provide attractive templates for building electrically driven and/or photodriven molecular motors.