Synthesis and Electrochemical Properties of cis- and trans-[Mo2(O2C-Fc)2(DArF)2] (O2C-Fc = Ferrocenecarboxylate; DArF = N,
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- 作者：Xu-Min Cai ; Teresa K. Zimmermann ; Alexander P枚thig ; Fritz E. K眉hn
- 刊名：Inorganic Chemistry
- 出版年：2015
- 出版时间：July 6, 2015
- 年：2015
- 卷：54
- 期：13
- 页码：6631-6640
- 全文大小：538K
- ISSN：1520-510X
文摘
The reaction of cis-[Mo2(O2C-Fc)2(NCCH3)4][BF4]2 (cis-1) with three electronically different N,N鈥?i>-diarylformamidinate (DArF) ligands [DArF = N,N鈥?diphenylformamidinate (DPhF), N,N鈥?di(p-trifluoromethylphenyl)formamidinate (DTfmpF), and N,N鈥?di(p-anisyl)formamidinate (DAniF)] results in products of the general composition [Mo2(O2C-Fc)2(DArF)2]. Even though the trans-[Mo2(O2C-Fc)2(DArF)2] isomers were originally expected to be the sole products, the corresponding cis-[Mo2(O2C-Fc)2(DArF)2] complexes were isolated as well via crystallization and verified unambiguously by X-ray crystallography. All novel complexes, namely, cis-[Mo2(O2C-Fc)2(DPhF)2] (cis-2a), cis-[Mo2(O2C-Fc)2(DTfmpF)2] (cis-2b), and trans-[Mo2(O2C-Fc)2(DAniF)2] (trans-2c), were studied regarding their electrochemical properties with respect to electrolyte, solvent, and ligand. The electron-donating ligand DArF鈥?/sup> enables the oxidation of the [Mo2]4+ unit prior to that of Fc, while the oxidation sequence is reversed when acetonitrile or diphosphine ligands are coordinated instead of formamidinate. In the case of trans-[Mo2(O2C-Fc)2(DAniF)2], interactions were found between the two redox-active ferrocenecarboxylate ligands, with a clear 螖E1/2 value originating from the peak-to-peak separation in DPV of around 100 mV with CH2Cl2 as solvent. Furthermore, the second oxidation of the Mo2-handle [Mo2]5+/[Mo2]6+ was exclusively observed with DAniF鈥?/sup> as the ligand. Similar absorption patterns in UV鈥搗is spectra were found within the series 2a鈥?b>2c, corresponding to similar structural and electronic features of the complexes.