Reactivity of the Dimer [{RuCl(渭-Cl)(畏3:畏3-C10H16)}2] (C10H16 = 2,7-Dimethylocta-2,6-diene-1,8-diyl) toward Guanidines: Acc

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• 作者：Luc谋虂a Men茅ndez-Rodr谋虂guez ; Eder Tom谩s-Mendivil ; Javier Francos ; Pascale Crochet ; Victorio Cadierno ; Antonio Anti帽olo ; Rafael Fern谩ndez-Gal谩n ; Fernando Carrillo-Hermosilla
• 刊名：Organometallics
• 出版年：2015
• 出版时间：June 22, 2015
• 年：2015
• 卷：34
• 期：12
• 页码：2796-2809
• 全文大小：700K
• ISSN：1520-6041

文摘

The novel bis(allyl)ruthenium(IV) guanidinate complexes [RuCl{魏²(N,N鈥?-C(NR)(NⁱPr)-NHⁱPr}(畏³:畏³-C₁₀H₁₆)] (C₁₀H₁₆ = 2,7-dimethylocta-2,6-diene-1,8-diyl; R = Ph (3a), 4-C₆H₄F (3b), 4-C₆H₄Cl (3c), 4-C₆H₄Me (3d), 3-C₆H₄Me (3e) 4-C₆H₄^tBu (3f)) have been synthesized by treatment of the dimeric precursor [{RuCl(渭-Cl)(畏³:畏³-C₁₀H₁₆)}₂] (1) with 4 equiv of the corresponding guanidine (ⁱPrHN)₂C鈺怤R (2a鈥?b>f). The easily separable guanidinium chloride salts [(ⁱPrHN)₂C(NHR)][Cl] (4a鈥?b>f) are also formed in these reactions. Attempts to generate analogous Ru(IV) guanidinate complexes from (ⁱPrHN)₂C鈺怤R (R = 2-C₆H₄Me (2g), 2,4,6-C₆H₂Me₃ (2h), 2,6-C₆H₃ⁱPr₂ (2i)) failed, due probably to the steric hindrance associated with the aryl group in these guanidines. On the other hand, the reaction of the dimer [{RuCl(渭-Cl)(畏³:畏³-C₁₀H₁₆)}₂] (1) with (ⁱPrHN)₂C鈺怤-4-C₆H₄C鈮 (2j) led to the selective formation of the mononuclear derivative [RuCl₂(畏³:畏³-C₁₀H₁₆){N鈮-4-C₆H₄-N鈺怌(NHⁱPr₂)₂}] (5), in which the guanidine coordinates to ruthenium through the pendant nitrile unit. This result contrasts with that obtained by employing the related Ru(II) dimer [{RuCl(渭-Cl)(畏⁶-p-cymene)}₂] (6), whose reaction with 2j afforded the expected guanidinate complex [RuCl{魏²(N,N鈥?-C(N-4-C₆H₄C鈮)(NⁱPr)-NHⁱPr}(畏⁶-p-cymene)] (7). Treatment of 7 with dimer 1 yielded the dinuclear Ru(II)/Ru(IV) derivative 8, via cleavage of the chloride bridges of 1 by the C鈮 group of 7. Reductive elimination of the 2,7-dimethylocta-2,6-diene-1,8-diyl chain in [RuCl{魏²(N,N鈥?-C(NR)(NⁱPr)-NHⁱPr}(畏³:畏³-C₁₀H₁₆)] (3a鈥?b>f) readily took place in the presence of an excess of 2,6-dimethylphenyl isocyanide, thus allowing the high-yield preparation of the octahedral ruthenium(II) compounds mer-[RuCl{魏²(N,N鈥?-C(NR)(NⁱPr)-NHⁱPr}(CN-2,6-C₆H₃Me₂)₃] (9a鈥?b>f). The structures of [RuCl{魏²(N,N鈥?-C(N-4-C₆H₄Me)(NⁱPr)-NHⁱPr}(畏³:畏³-C₁₀H₁₆)] (3d), [RuCl{魏²(N,N鈥?-C(N-4-C₆H₄C鈮)(NⁱPr)-NHⁱPr}(畏⁶-p-cymene)] (7), and mer-[RuCl{魏²(N,N鈥?-C(N-4-C₆H₄^tBu)(NⁱPr)-NHⁱPr}(CN-2,6-C₆H₃Me₂)₃] (9f), as well as those of the guanidinium chloride salts 4a鈥?b>c, were unequivocally confirmed by X-ray diffraction methods. In addition, the catalytic behavior of the guanidinate complexes 3a鈥?b>f and 9a鈥?b>f in the redox isomerization of allylic alcohols was also explored.