Structure and Electrochemistry of Heterobimetallic Ferrocenecarboxylatoruthenium(II) Complexes
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- 作者：Ian W. Wyman ; Tara J. Burchell ; Kathy N. Robertson ; T. Stanley Cameron ; and Manuel A. S. Aquino
- 刊名：Organometallics
- 出版年：2004
- 出版时间：October 25, 2004
- 年：2004
- 卷：23
- 期：22
- 页码：5353 - 5364
- 全文大小：239K
- 年卷期：v.23,no.22(October 25, 2004)
- ISSN：1520-6041
文摘
The mixed-valent diruthenium complexes [Ru2(
-O2CR)4L2](PF6) (where R = CH3, L =H2O or R = Fc (ferrocenyl), L = MeOH) were reacted with the three diphosphine (dpp) ligandsbis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), and 1,3-bis(diphenylphosphino)propane (dppp) to yield, via a disassembly reaction, the monoruthenium(II) complexes [Ru(
2-O2CR)(dpp)2](PF6) (R = CH3 and dpp = dppm (1), dpp = dppe(2), dpp = dppp (3); R = Fc and dpp = dppm (4), dpp = dppe (5), dpp = dppp (6)). All sixcomplexes were characterized by elemental analysis, IR and NMR (1H and 31P) spectroscopy,cyclic and Osteryoung square wave voltammetry, and X-ray crystallography. Complexes 4-6are rare examples of structurally characterized ruthenium complexes with 2-boundferrocenecarboxylate ligands, and they are unique in displaying a metal and an organometallic center. The electrochemical measurements reveal an essentially reversible ruthenium-centered redox process for complexes 2 and 3, which becomes irreversible in the presence ofthe ferrocenyl group in complexes 4-6. The iron-centered redox process in complexes 4-6is chemically reversible. The separation between these redox processes is large (>1.0 V),leading to a stable "mixed-valent" state, and increases in the potential separation of thesetwo redox processes over the separation seen between the redox potentials of the isolatedruthenium and ferrocenecarboxylate fragments may indicate the possibility of metal-metalinteractions. A mechanism for the disassembly process, exploited in the synthetic procedure,is postulated.
-O2CR)4L2](PF6) (where R = CH3, L =H2O or R = Fc (ferrocenyl), L = MeOH) were reacted with the three diphosphine (dpp) ligandsbis(diphenylphosphino)methane (dppm), 1,2-bis(diphenylphosphino)ethane (dppe), and 1,3-bis(diphenylphosphino)propane (dppp) to yield, via a disassembly reaction, the monoruthenium(II) complexes [Ru(2-O2CR)(dpp)2](PF6) (R = CH3 and dpp = dppm (1), dpp = dppe(2), dpp = dppp (3); R = Fc and dpp = dppm (4), dpp = dppe (5), dpp = dppp (6)). All sixcomplexes were characterized by elemental analysis, IR and NMR (1H and 31P) spectroscopy,cyclic and Osteryoung square wave voltammetry, and X-ray crystallography. Complexes 4-6are rare examples of structurally characterized ruthenium complexes with 2-boundferrocenecarboxylate ligands, and they are unique in displaying a metal and an organometallic center. The electrochemical measurements reveal an essentially reversible ruthenium-centered redox process for complexes 2 and 3, which becomes irreversible in the presence ofthe ferrocenyl group in complexes 4-6. The iron-centered redox process in complexes 4-6is chemically reversible. The separation between these redox processes is large (>1.0 V),leading to a stable "mixed-valent" state, and increases in the potential separation of thesetwo redox processes over the separation seen between the redox potentials of the isolatedruthenium and ferrocenecarboxylate fragments may indicate the possibility of metal-metalinteractions. A mechanism for the disassembly process, exploited in the synthetic procedure,is postulated.