Ruthenium(II) Isocyanide Complexes Supported by Triazacyclononane/Trithiacyclononane and Aromatic Diimine: Structural, Spectroscopic, and Theoretical Studies

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• 作者：Chun-Yuen Wong ; Lo-Ming Lai ; Hung-Fan Leung ; Sze-Ho Wong
• 刊名：Organometallics
• 出版年：2009
• 出版时间：June 22, 2009
• 年：2009
• 卷：28
• 期：12
• 页码：3537-3545
• 全文大小：288K
• 年卷期：v.28,no.12(June 22, 2009)
• ISSN：1520-6041

文摘

Ruthenium(II)−isocyanide complexes bearing cyclic tridentate amine/thioether (1,4,7-trimethyl-1,4,7-triazacyclononane, Me₃Tacn/1,4,7-trithiacyclononane, [9]aneS3) and aromatic diimine (1,10-phenanthroline, phen/2,2′-bipyridine, bpy) have been prepared. The molecular structures of [(Me₃Tacn)(bpy)Ru(t-BuNC)]²⁺, [([9]aneS3)(phen)Ru(t-BuNC)]²⁺, and the nitrile-ligated congener [(Me₃Tacn)(phen)Ru(CH₃CN)]²⁺ show that the Ru−C distances in the isocyanide complexes are sensitive to the electron richness of the metal center, and isocyanide has a stronger trans influence than nitrile. The lowest-energy dipole-allowed absorptions for the isocyanide and nitrile complexes (λ_max = 330−405 and 417−458 nm, respectively, ε_max = (3−6) × 10³ dm³ mol⁻¹ cm⁻¹) are assigned as d_π(Ru^II) → π*(diimine) metal-to-ligand charge transfer (MLCT) transitions. These complexes are emissive in glassy MeOH/EtOH at 77 K upon photoexcitation and give emission at λ_max = 477−601 nm. Density functional theory (DFT) calculations and charge decomposition analysis (CDA) have been used to compare the σ-donating and π-accepting abilities of nitrile and different organometallic ligands including isocyanide, methoxycarbene, and allenylidene. The molecular structure of the cofacial bioctahedral complex [(Me₃Tacn)Ru(μ-Cl)₃Ru(Me₃Tacn)]⁺ has also been determined, and the Ru···Ru distance has been found to be 3.1842(6) Å.