Characterization of the Low-Energy Electronic Excited States of Benzoyl-Substituted Ruthenocenes

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• 作者：Cynthia T. Sanderson ; Jessica A. Quinlan ; Richard C. Conover ; Michael K. Johnson ; Michael Murphy ; Richard A. Dluhy ; and Charles Kutal
• 刊名：Inorganic Chemistry
• 出版年：2005
• 出版时间：May 2, 2005
• 年：2005
• 卷：44
• 期：9
• 页码：3283 - 3289
• 全文大小：104K
• 年卷期：v.44,no.9(May 2, 2005)
• ISSN：1520-510X

文摘

Electronic absorption and resonance Raman spectral studies of benzoylruthenocene (BRc) and 1,1'-dibenzoylruthenocene (DRc) indicate that the low-energy electronic excited states of these 4d⁶ metallocenes possess metal-to-ligand charge transfer (MLCT) character. While this MLCT contribution should weaken the metal-ring bonding inthe excited state, neither compound is photosensitive in nonhalogenated solvents such as methanol, acetonitrile,and cyclohexane. In contrast, irradiating BRc and DRc in the good electron-accepting solvent, carbon tetrachloride,results in ring loss via a pathway that appears to originate from a charge-transfer-to-solvent excited state. Bothmetallocenes function as photoinitiators for the anionic polymerization of ethyl 2-cyanoacrylate, and the kineticsand mechanism of this process have been investigated. Comparing the present results on BRc and DRc withthose reported earlier for the corresponding benzoyl-substituted ferrocene compounds reveals some interestingcommonalities and differences between the excited-state properties of these 3d and 4d metallocenes.