On the Role of the Bridging Dicyanamidobenzene Ligand in a New Binuclear Ruthenium Complex: [{Ru(tpy)(thd)}2(-dicyd)][PF
详细信息 查看全文
- 作者：Muriel Fabre ; Joë ; l Jaud ; Mohamed Hliwa ; Jean-Pierre Launay ; Jacques Bonvoisin
- 刊名：Inorganic Chemistry
- 出版年：2006
- 出版时间：November 13, 2006
- 年：2006
- 卷：45
- 期：23
- 页码：9332 - 9345
- 全文大小：477K
- 年卷期：v.45,no.23(November 13, 2006)
- ISSN：1520-510X
文摘
The dicyanamidobenzene-bridge diruthenium complex [{Ru(tpy)(thd)}2(
-dicyd)][PF6] ([3][PF6]) (dicyd = 1,4-dicyanamidobenzene, tpy = 2,2':6',2' '-terpyridine, thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and its mononuclearcounterpart [Ru(tpy)(thd)(Ipcyd)] (2) [Ipcyd = 4-iodophenylcyanamide anion (Ipcyd-)] were synthesized and fullycharacterized. Cyclic voltammetry of 3 showed the presence of four reversible one-electron redox couples. UV-vis-NIR spectroelectrochemistry and EPR spectroscopy of the electrogenerated paramagnetic intermediates wereused to ascertain the oxidation-state distribution. The stable starting dinuclear complex 3+ is found to be a ligand-centered anion radical as shown by EPR spectroscopy, magnetic susceptibility measurements, and DFT calculations.Oxidation of 3+ to 32+ led to an EPR silent system due to substantial intramolecular antiferromagnetic interactionof the electron spins carried by the low spin ruthenium(III) atom and the bridging anion radical dicyanamido (dicyd
-),an observation which was supported by UV-vis-NIR, X-ray structure, and DFT calculations. Complex 33+ presentedan EPR spectra consistent with a total effective spin S = 1/2 issued from an antiferromagnetic interaction of electronspins carried by two low spin ruthenium(III) atoms and the bridging anion radical dicyd- in accordance with UV-vis-NIR. This study shows that the dicyanamidobenzene bridging ligand has indubitably a noninnocent behavior.
-dicyd)][PF6] ([3][PF6]) (dicyd = 1,4-dicyanamidobenzene, tpy = 2,2':6',2' '-terpyridine, thd = 2,2,6,6-tetramethyl-3,5-heptanedione) and its mononuclearcounterpart [Ru(tpy)(thd)(Ipcyd)] (2) [Ipcyd = 4-iodophenylcyanamide anion (Ipcyd-)] were synthesized and fullycharacterized. Cyclic voltammetry of 3 showed the presence of four reversible one-electron redox couples. UV-vis-NIR spectroelectrochemistry and EPR spectroscopy of the electrogenerated paramagnetic intermediates wereused to ascertain the oxidation-state distribution. The stable starting dinuclear complex 3+ is found to be a ligand-centered anion radical as shown by EPR spectroscopy, magnetic susceptibility measurements, and DFT calculations.Oxidation of 3+ to 32+ led to an EPR silent system due to substantial intramolecular antiferromagnetic interactionof the electron spins carried by the low spin ruthenium(III) atom and the bridging anion radical dicyanamido (dicyd-),an observation which was supported by UV-vis-NIR, X-ray structure, and DFT calculations. Complex 33+ presentedan EPR spectra consistent with a total effective spin S = 1/2 issued from an antiferromagnetic interaction of electronspins carried by two low spin ruthenium(III) atoms and the bridging anion radical dicyd- in accordance with UV-vis-NIR. This study shows that the dicyanamidobenzene bridging ligand has indubitably a noninnocent behavior.