Rigaut Stéphane, Olivier Céline, Costuas Karine, Choua Sylvie, Fadhel Omrane, Massue Julien, Turek Philippe, Saillard Jean-Yves, Dixneuf Pierre H, Touchard Daniel
UMR 6226 CNRS--Université de Rennes 1, Sciences Chimiques de Rennes, Campus de Beaulieu, F-35042 Rennes Cedex, France.
J Am Chem Soc. 2006 May 3;128(17):5859-76. doi: 10.1021/ja0603453.
Two methodologies of C-C bond formation to achieve organometallic complexes with 7 or 9 conjugated carbon atoms are described. A C7 annelated trans-[Cl(dppe)2Ru=C=C=C-CH=C(CH2)-C[triple bond]C-Ru(dppe)2Cl][X] (X = PF6, OTf) complex is obtained from the diyne trans-[Cl(dppe)2Ru-(C[triple bond]C)2-R] (R = H, SiMe3) in the presence of [FeCp2][PF6] or HOTf, and C7 or C9 complexes trans-[Cl(dppe)2Ru-(C[triple bond]C)n-C(CH3)=C(R1)-C(R2)=C=C=Ru(dppe)2Cl][X] (n = 1, 2; R1 = Me, Ph, R2 = H, Me; X = BF4, OTf) are formed in the presence of a polyyne trans-[Cl(dppe)2Ru-(C[triple bond]C)n-R] (n = 2, 3; R = H, SiMe3) with a ruthenium allenylidene trans-[Cl(dppe)2Ru=C=C=C(CH2R1)R2][X]. These reactions proceed under mild conditions and involve cumulenic intermediates [M+]=(C=)nCHR (n = 3, 5), including a hexapentaenylidene. A combination of chemical, electrochemical, spectroscopic (UV-vis, IR, NIR, EPR), and theoretical (DFT) techniques is used to show the influence of the nature and conformation of the bridge on the properties of the complexes and to give a picture of the electron delocalization in the reduced and oxidized states. These studies demonstrate that the C7 bridging ligand spanning the metal centers by almost 12 angstroms is implicated in both redox processes and serves as a molecular wire to convey the unpaired electron with no tendency for spin localization on one of the halves of the molecules. The reactivity of the C7 complexes toward protonation and deprotonation led to original bis(acetylides), vinylidene-allenylidene, or carbyne-vinylidene species such as trans-[Cl(dppe)2Ru[triple bond]C-CH=C(CH3)-CH=C(CH3)-HC=C=Ru(dppe)2Cl][BF4]3.
描述了两种形成碳 - 碳键以制备具有7个或9个共轭碳原子的有机金属配合物的方法。在[FeCp2][PF6]或HOTf存在下，由二炔反式 - [Cl(dppe)2Ru-(C≡C)2-R]（R = H，SiMe3）得到一个C7稠合的反式 - [Cl(dppe)2Ru = C = C = C-CH = C(CH2)-C≡C-Ru(dppe)2Cl][X]（X = PF6，OTf）配合物，并且在多炔反式 - [Cl(dppe)2Ru-(C≡C)n-R]（n = 2，3；R = H，SiMe3）与钌亚联烯反式 - [Cl(dppe)2Ru = C = C = C(CH2R1)R2][X]存在下形成C7或C9配合物反式 - [Cl(dppe)2Ru-(C≡C)n-C(CH3)=C(R1)-C(R2)=C = C = Ru(dppe)2Cl][X]（n = 1，2；R1 = Me，Ph，R2 = H，Me；X = BF4，OTf）。这些反应在温和条件下进行，涉及累积烯中间体[M+]=(C=)nCHR（n = 3，5），包括一个六戊烯叉。结合化学、电化学、光谱（紫外 - 可见、红外、近红外、电子顺磁共振）和理论（密度泛函理论）技术来展示桥连基团的性质和构象对配合物性质的影响，并描绘还原态和氧化态下的电子离域情况。这些研究表明，跨越金属中心近12埃的C7桥连配体参与了两个氧化还原过程，并作为分子导线来传递未成对电子，且没有在分子的任何一半上自旋定位的趋势。C7配合物对质子化和去质子化的反应活性导致了原始的双（乙炔化物）、亚乙烯基 - 亚联烯基或卡宾 - 亚乙烯基物种，如反式 - [Cl(dppe)2Ru≡C-CH = C(CH3)-CH = C(CH3)-HC≡C = Ru(dppe)2Cl][BF4]3。
