Specific Synthesis and Reaction of Hetero- and Homobridged Diruthenium Carbonyl Complexes Containing One or Two μ-Azolato Bridges
Resource
Organometallics 15 (13): 2979-2987
Journal
Organometallics
Journal Volume
15
Journal Issue
13
Pages
2979-2987
Date Issued
1996
Date
1996
Author(s)
Shiu, Kom-Bei
Lee, Wei-Ming
Wang, Chen-Lan
Wang, Sue-Lein
Liao, Fen-Ling
Wang, Ju-Chun
Liou, Lin-Shu
Lee, Gene-Hsiang
Chiang, Michael Y.
Abstract
Diruthenium(I) carbonyl complexes with either hetero- or homobridges, [Ru2(μ-Pz)2(CO)4(HPz)2] (1), [Ru2(μ-Pz')(μ-O2CMe)(CO)4(HPz')2] (2), and [Ru2(μ-Pz')2(CO)4(HPz')2] (3), can be prepared specifically. These complexes reacted with either nucleophiles or electrophiles to produce selectively only one product. The terminal azole groups, pyrazole (HPz) or 3,5-dimethylpyrazole (HPz'), of 1−3 are easily replaced by the phosphine ligands to give [Ru2(μ-Pz)2(CO)4(PPh3)2] (4), [Ru2(μ-Pz')(μ-O2CMe)(CO)4(PPh3)2] (5), [Ru2(μ-Pz')2(CO)4(PPh3)2] (6), and [Ru2(μ-Pz)2(CO)4(η1-dppm)2] (7). The μ-acetato bridge is more fragile than the μ-azolato bridge, and only the former bridge of 5 can be replaced by Pz- and SR- to afford [Ru2(μ-Pz')(μ-Pz)(CO)4(PPh3)2] (8) and [Ru2(μ-Pz')(μ-SR)(CO)4(PPh3)2] (R = Ph (9), tBu (10)). Heating the mixture of 3 with dppm in THF gave a product retaining all the μ-azolato bridges but losing two carbonyls, [Ru2(μ-Pz')2(CO)2(μ1,η2-dppm)2] (11), whereas a similar reaction between 1−3 and nitrogen-bidentate ligands gave products retaining all four carbonyls but only one μ-azolato bridge, [Ru2(μ-L)(μ-CO)2(CO)2(μ1,η2-(N−N))2]+ (L = Pz, N−N = bpy ([12]+), phen ([13]+); L = Pz', N−N = bpy ([14]+), phen ([15]+)). The electrophilic addition of 4 with I2 produced [Ru2(μ-Pz)2(μ-I)(CO)4(PPh3)2][I3] (16). The X-ray structure of this product confirms the cleavage of the Ru−Ru bond rather than the μ-azolato bridges. However, the μ-azolato and -acetato bridges, as well as the terminal azole groups, of 1−6 can be easily removed by an electrophilc reagent such as Et3O+BF4- in the presence of MeCN to give [Ru2(CO)4(MeCN)6][BF4]2 and [Ru2(CO)4(MeCN)4(PPh3)2][BF4]2.
Type
journal article
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