Photophysical and Theoretical Studies of Ruthenium(II)−Acetylide and −Cyanide Complexes with Aromatic Diimine and Trithiacyclononane

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• 作者：Chun-Yuen Wong ; Lo-Ming Lai ; Siu-Chung Chan ; Lai-Hung Tai
• 刊名：Organometallics
• 出版年：2010
• 出版时间：December 13, 2010
• 年：2010
• 卷：29
• 期：23
• 页码：6259-6266
• 全文大小：927K
• 年卷期：v.29,no.23(December 13, 2010)
• ISSN：1520-6041

文摘

Ruthenium(II)−chloride, −cyanide, and −phenylacetylide complexes bearing aromatic diimine (2,2′-bipyridine (bpy), 4,4′-dimethyl-2,2′-bipyridine (Me₂bpy), or dipyrido-[3,2-f:2′,3′-h]-quinoxaline (dpq)) and cyclic tridentate thioether 1,4,7-trithiacyclononane ([9]aneS3) have been prepared. The crystal structures of [Ru([9]aneS3)(bpy)(C≡N)](PF₆) and [Ru([9]aneS3)(diimine)(C≡CPh)](PF₆) (diimine = bpy and Me₂bpy) reveal Ru−C distances of 2.024(4) and 2.030(3)−2.038(2) Å, respectively. The oxidation waves for the complexes are attributed to the removal of an electron from a [d_π(Ru) + L] hybrid orbital (L = −Cl, −C≡N, and −C≡CPh), whereas the reduction waves are assigned as reduction of the aromatic diimine. The lowest-energy dipole-allowed absorptions for the complexes (λ_max = 403−475 nm, ε_max = (3−5) × 10³ dm³ mol⁻¹ cm⁻¹) are assigned as [d_π(Ru^II) + L] → π*(diimine) charge transfer transitions. All the acetylide complexes weakly emit at λ_max = 663−680 nm in CH₃CN at 298 K with quantum yield = (5−8) × 10⁻⁴ (λ_ex = 450 nm), and these emissions are described as [d_π(Ru) + L] → π*(diimine) triplet charge transfer in nature. Density functional theory (DFT) and time-dependent-DFT (TD-DFT) calculations have been employed to examine the composition of the frontier molecular orbitals and the nature of the electronic transitions associated with the complexes.