888734-97-2Relevant academic research and scientific papers
Further chemistry of ruthenium alkenyl acetylide complexes: Routes to allenylidene complexes via a series of electrophilic addition reactions
Hall, Michael R.,Korb, Marcus,Moggach, Stephen A.,Low, Paul J.
, p. 2838 - 2853 (2020)
The methyl substituents in the cationic allenylidene complexes trans-[Ru{C=C=C(Me)R}Cl(dppe)2]OTf ([1a?f]OTf) are readily deprotonated to give the corresponding alkenyl acetylide complexes trans-[Ru{C=CC(=CH2)R}Cl(dppe)2] (3; R = Me (a), Ph (b), cC5H10 (c), 4-MeS-C6H4 (d), cC4H3S (e), cC5H4N (f)). Similar chemistry is also observed from [Ru{C=C=C(Me)Ph}(dppe)Cp*]PF6 ([2b]PF6) and [Ru{C=C=C(Me)(4-MeS-C6H4)}(dppe)Cp*]PF6([2b]PF6), chosen to broaden the reaction scope, giving [Ru{C= CC(=CH2)Ph}(dppe)Cp*] (4b) and [Ru{C=C=C(CH2)(4-MeS-C6H4)}(dppe)Cp*] (4d). In turn, reactions of 3b,d and 4b,d with the [BF4]? salt of the electrophilic tritylium [CPh3]+ cation give the functionalized allenylidene complexes trans-[Ru{C=C=C(CH2CPh3)R}Cl(dppe)2]BF4 ([5b,d]BF4) and [Ru{C=C=C(CH2CPh3)R}(dppe)Cp*]BF4 ([6b,d]BF4) formed by addition of the electrophile to the remote vinylic carbon (C(δ)). Although trans-[Ru{C=C=C(CH2CPh3)Me}Cl(dppe)2]BF4 ([5a]BF4) could not be successfully purified from reactions of 3a with [CPh3]BF4, deprotonation of the crude product gave the Zaitsev vinyl product trans-[Ru{C=CC(=CHCPh3)Me}Cl(dppe)2] (7a) in good yield. The initial cycloheptatrienyl adducts formed from reactions of 3b,d and 4b,d with the tropylium salt [C7H7]BF4 undergo a ring-contraction process in chloroform solutions upon exposure to air, to give the styrene-like products trans-[Ru{C=C=C(R)C(H)=CHPh}Cl(dppe)2]BF4 ([10b,d]BF4) and [Ru{C=C= C(R)C(H)=CHPh}(dppe)Cp*]BF4 ([11b,d]BF4), through what is believed to be a radical mechanism mediated by triplet oxygen.
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 (2007/10/03)
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.
