505094-05-3Relevant academic research and scientific papers
C7 and C9 carbon-rich bridges in diruthenium systems: Synthesis, spectroscopic, and theoretical investigations of different oxidation states
Rigaut, Stephane,Olivier, Celine,Costuas, Karine,Choua, Sylvie,Fadhel, Omrane,Massue, Julien,Turek, Philippe,Saillard, Jean-Yves,Dixneuf, Pierre H.,Touchard, Daniel
, p. 5859 - 5876 (2006)
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≡C-Ru(dppe) 2CI][X] (X = PF6, OTf) complex is obtained from the diyne trans-[Cl(dppe)2Ru-(C≡C)2-R] (R = H, SiMe 3) in the presence of [FeCp2][PF6] or HOTf, and C7 or C9 complexes trans-[Cl(dppe)2Ru- (C≡C)n-C(CH3)=C(R1)-C(R 2)=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≡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 A 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≡C-CH=C(CH3) CH=C(CH3)-HC=C=Ru(dppe)2Cl][BF4]3.
Amphoteric allenylidene ruthenium complexes and the first dinuclear ruthenium species with a bis-alkenyl carbyne bridging ligand
Rigaut, Stephane,Touchard, Daniel,Dixneuf, Pierre H.
, p. 3980 - 3984 (2003)
Cationic ruthenium(II) allenylidenes trans-[Cl(dppe)2Ru=C=C=C(CH3)R]BF4 (R = Ph, CH3) can be deprotonated to generate neutral alkenyl acetylide metal trans-[Cl(dppe)2Ru-C≡C-C(=CH2)R] or protonated with HBF4·Et2O to lead to dicationic ruthenium(II) carbynes trans-[Cl(dppe)2Ru≡C-CH=C(CH3)R] (BF4)2. The latter reaction was applied to transform a conjugated bis-allenylidene bridged diruthenium complex, trans-[Cl(dppe)2Ru=C=C=C(CH3)-p-C6H4 -(CH3)C=C=C=Ru(dppe)2Cl] (BF4)2, into the first bis-alkenyl carbyne ruthenium species trans-[Cl(dppe)2Ru≡C-CH=C(CH3)-p-C6 H4-(CH3)C=HC-C≡Ru(dppe)2Cl]- (BF4)4.
