Syntheses and Properties of a Series of Oxo-Centered Triruthenium Complexes and Their Bridged Dimers with Isocyanide Ligands at Terminal and Bridging Positions
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- 作者：Ken-ichiro Ota ; Hirokazu Sasaki ; Taeko Matsui ; Tomohiko Hamaguchi ; Tadashi Yamaguchi ; Tasuku Ito ; Hiroaki Kido ; and Clifford P. Kubiak
- 刊名：Inorganic Chemistry
- 出版年：1999
- 出版时间：September 6, 1999
- 年：1999
- 卷：38
- 期：18
- 页码：4070 - 4078
- 全文大小：301K
- 年卷期：v.38,no.18(September 6, 1999)
- ISSN：1520-510X
文摘
Seven new oxo-centered triruthenium complexes with 2,6-dimethylphenyl isocyanide (CNXy) as a terminal ligand,[Ru3(O)(CH3CO2)6(CNXy)n(L)3-n] {L = CO, n = 2 (1); L = pyridine (py), n = 1 (2); L = 4-(dimethylamino)pyridine (dmap), n = 1 (3); L = py, n = 2 (4); L = dmap, n = 2 (5); n = 3 (6); L = 5-(4-pyridyl)-10,15,20-triphenylporphine, n = 2 (7)}, three new pyrazine (pz) bridged dimers of triruthenium complexes with terminalisocyanide ligands, [{Ru3(O)(CH3CO2)6(CNXy)n(L)2-n}2(
ntities/mgr.gif">-pz)] {L = py, n = 1 (8); L = dmap, n = 1 (9); n =2 (10)}, and three new 1,4-phenylene diisocyanide bridged dimers, [{Ru3(O)(CH3CO2)6(L)2}2(ntities/mgr.gif">-CNC6H4NC)]{L = py (11); L = dmap (12); L = CNXy (13)}, were prepared. All the Ru3(O) cluster core in these compoundshave the formal oxidation state of RuIII2RuII in the isolated state. In contrast to the related carbonyl derivatives,the isocyanide complexes gave triruthenium complexes with more than one isocyanide ligand, reflecting the lower
acidity of isocyanides. In the mixed carbonyl/isocyanide complex [Ru3(O)(CH3CO2)6(CO)(CNXy)2] (1), thecarbonyl and isocyanide ligands compete in acidity for the Ru3(O) cluster core, and as a result 1 undergoes afacile elimination of the CO ligand followed by substitution. With use of this reaction, many other trirutheniumisocyanide complexes were prepared. Coordination of isocyanide ligands to these triruthenium complexes causesthe redox potentials to be shifted anodically relative to the corresponding pyridine derivatives. The pz bridgeddimers, 8 and 9, gave stable one-electron-reduced species which are in the mixed-valence state with respect tothe Ru3 core, as is evidenced by a large redox wave splitting for the RuIII2RuII-pz-RuIII2RuII/RuIII2RuII-pz-RuIIIRuII2/RuIIIRuII2-pz-RuIIIRuII2 process (
E1/2 = 349 mV for 8 and 393 mV for 9). On the other hand, 1,4-phenylene diisocyanide bridged Ru3 dimers 11-13 gave no stable mixed-valence state, indicating that the electroniccommunication between the Ru3 units through this bridge is negligibly small. The compound [Ru3(O)(CH3CO2)6(CNXy)(py)2] (2) crystallized in the orthorhombic Pbcn space group with a = 18.393(5) Å, b = 14.428(2) Å, c= 17.396(2) Å, and Z = 4. A comparison of Ru-O(acetate) distances reveals that the site coordinated by theisocyanide ligand is formally Ru(II).
ntities/mgr.gif">-pz)] {L = py, n = 1 (8); L = dmap, n = 1 (9); n =2 (10)}, and three new 1,4-phenylene diisocyanide bridged dimers, [{Ru3(O)(CH3CO2)6(L)2}2(ntities/mgr.gif">-CNC6H4NC)]{L = py (11); L = dmap (12); L = CNXy (13)}, were prepared. All the Ru3(O) cluster core in these compoundshave the formal oxidation state of RuIII2RuII in the isolated state. In contrast to the related carbonyl derivatives,the isocyanide complexes gave triruthenium complexes with more than one isocyanide ligand, reflecting the lower acidity of isocyanides. In the mixed carbonyl/isocyanide complex [Ru3(O)(CH3CO2)6(CO)(CNXy)2] (1), thecarbonyl and isocyanide ligands compete in acidity for the Ru3(O) cluster core, and as a result 1 undergoes afacile elimination of the CO ligand followed by substitution. With use of this reaction, many other trirutheniumisocyanide complexes were prepared. Coordination of isocyanide ligands to these triruthenium complexes causesthe redox potentials to be shifted anodically relative to the corresponding pyridine derivatives. The pz bridgeddimers, 8 and 9, gave stable one-electron-reduced species which are in the mixed-valence state with respect tothe Ru3 core, as is evidenced by a large redox wave splitting for the RuIII2RuII-pz-RuIII2RuII/RuIII2RuII-pz-RuIIIRuII2/RuIIIRuII2-pz-RuIIIRuII2 process (E1/2 = 349 mV for 8 and 393 mV for 9). On the other hand, 1,4-phenylene diisocyanide bridged Ru3 dimers 11-13 gave no stable mixed-valence state, indicating that the electroniccommunication between the Ru3 units through this bridge is negligibly small. The compound [Ru3(O)(CH3CO2)6(CNXy)(py)2] (2) crystallized in the orthorhombic Pbcn space group with a = 18.393(5) Å, b = 14.428(2) Å, c= 17.396(2) Å, and Z = 4. A comparison of Ru-O(acetate) distances reveals that the site coordinated by theisocyanide ligand is formally Ru(II).