658043-44-8Relevant academic research and scientific papers
Synthesis of ruthenium–dithiocarbamate chelates bearing diphosphine ligands and their use as latent initiators for atom transfer radical additions
Aldin, Mohammed Zain,Delaude, Lionel,Zaragoza, Guillermo
, (2021/08/03)
Nine representative [Ru(S2CNEt2)2(diphos)] complexes were prepared in almost quantitative yields (91–97%) from [RuCl2(p-cymene)]2, sodium diethyldithiocarbamate trihydrate, and a diphosphine (dppm, dppe, dppp, dppb, dpppe, dppen, dppbz, dppf, or DPEphos), using a novel, straightforward, one-pot procedure. The recourse to a monomodal microwave reactor was instrumental in reaching the thermodynamic equilibria favoring the targeted monometallic trichelates. All the products were fully characterized by using various analytical techniques and the molecular structures of seven of them were determined by X-ray crystallography. NMR, XRD, and IR spectroscopies evidenced a significant contribution of the thioureide resonance form Et2N+=CS22– to the electronic structure of the 1,1-dithiolate ligand. MS/MS spectrometry showed the formation of phosphine-free [Ru(S2CNEt2)2]+ cations in the gas phase, except when starting from [Ru(S2CNEt2)2(dppbz)]. The activity of the nine complexes was probed in three different catalytic processes, viz., the cyclopropanation of styrene with ethyl diazoacetate, the synthesis of vinyl esters from benzoic acid and 1-hexyne, and the atom transfer radical addition (ATRA) of carbon tetrachloride and methyl methacrylate. In the first two reactions, the saturated trichelates were poorly efficient. This was most likely due to their high stability, which prevented the formation of coordinatively unsaturated species. Contrastingly, with a turnover number of 2000 and an initial turnover frequency of 2080 h–1 for a 0.05 mol% catalyst loading, the [Ru(S2CNEt2)2(dppm)] complex emerged as a very robust, latent ATRA initiator, whose activity matched or outperformed those displayed by the most efficient ruthenium catalysts described so far.
Synthetic, X-ray diffraction, electrochemical, and density functional theoretical studies of (indenyl)ruthenium complexes containing dithiolate ligands
Sin, Yee Ng,Tan, Jialin,Wai, Yip Fan,Weng, Kee Leong,Lai, Yoong Goh,Webster, Richard D.
, p. 3827 - 3840 (2008/03/14)
Halide substitution of the complexes [(Ind)Ru(L2)X] {Ind = η5-C9H7. 1: (L2) = dppf [1,1′-bis(diphenylphosphanyl)ferrocene], X = Cl; 2: (L2) = dppm [1,1′-bis(diphenylphosphanyl)methane], X = Cl; and 18: (L2) = (CO)2, X = I} with the 1,1-dithiolates -S 2CNR2 (dialkyl dithiocarbamates for R = Me, Et, and C 5H10), S2COR (alkyl xanthates for R = Et and iPr), and -S2PR2 (dithiophosphinates for R = Et and Ph) showed that the lability of the indenyl ligand is influenced by the nature of both the coligand and the incoming dithiolate, as well as the solvent. In addition to dithiolate derivatives, the reactions also produced the hydride species [(Ind)Ru(diphos)H] in solvent- and stoichiometry-dependent yields. The observed dependence of lability of Ind on (L2) follows the order, dppf 2, in agreement with the electron-donor capability of L2, as well as the estimation of lowest activation energy for the η5 → η3 ring slippage process in the series of complexes [(Ind)Ru(L)2(S2COMe)] (L = PMeH2, PH3, CO) for L = CO. The computational study also indicated an indenyl lability order for dithiolate substitution (dithiocarbamate > xanthate), in agreement with experimental findings. The dissociation of the indenyl ligand in chloro substitution of 1 by -S 2CNEt2 was found to be exhaustive in a polar solvent like MeOH, but only partial in CH2Cl2. Cyclic voltammetry experiments indicated that [(Ind)Ru(dppf)(η1-S2COiPr)] (10) and [(Ind)Ru(dppf)(η1-S2PPh2)] (13) can be oxidized in one-electron chemical irreversible or chemical reversible processes, respectively (at a scan rate of 100 mV/s), at about 0 V versus Fc/Fc+. Complex 13 underwent additional one-electron oxidation processes at +0.5 and +0.8 V versus Fc/Fc+. The new complexes have all been characterized spectroscopically, and some (four containing the indenyl ligand and three of the non-indenyl type) by X-ray diffraction as well. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Comparative reactivity studies of dppf-containing CpRuII and (C6Me6)RuII complexes towards different donor ligands (dppf=1,1′-bis(diphenylphosphino)ferrocene)
Lu, Xiu Lian,Vittal, Jagadese J.,Tiekink, Edward R.T.,Tan,Kuan, Seah Ling,Goh, Lai Yoong,Hor, T.S. Andy
, p. 1978 - 1990 (2007/10/03)
[CpRu(dppf)Cl] (Cp=η5-C5H5) (1) and [(HMB)Ru(dppf)Cl]PF6 ((HMB)=η6-C6Me6) (3) react with different donor ligands to give rise to N-, P- and S-bonded complexes. The stoichiometric reactions of 1 and 3 with NaNCS give the mononuclear complexes [CpRu(dppf)(NCS)] (2) and [(HMB)Ru(dppf)(NCS)]PF6 (4), respectively, in yields above 80%, while 3 also gives a dppf-bridged diruthenium complex [(HMB)Ru(NCS)2]2 (μ-dppf) (5) in 67% yield from reaction with four molar equivalents of NaNCS. Compound 5 is also obtained in 70% yield from the reaction of 4 with excess NaNCS. With CH3CN in the presence of salts, both 1 and 3 give their analogous solvento derivatives [CpRu(dppf) (CH3CN)] BPh4 (6) and [(HMB)Ru(dppf) (CH3CN)] (PF6)2 (7). With phosphines, the reaction of 1 gives chloro-displaced complexes [(CpRu(dppf)L]PF6 (L =PMe3 (8), PMe2Ph(9), whereas the reaction of 3 with PMe2Ph leads to substitution of dppf, giving [(HMB)Ru(PMe2Ph)2Cl] PF6 (10). The reaction of 1 with NaS2CNEt2 gives a dinuclear dppf-bridged complex [{CpRu(S2CNEt2)} 2(μ-dppf)] (11), whereas that of 3 results in loss of the HMB ligand giving a mononuclear complex [Ru(dppf) (S2CNEt2)2] (12). With elemental sulfur S8, 1 is oxidized to give a dinuclear CpRuIII dppf-chelated complex [{CpRu(dppf)}2(μ-S2)] (BPh4)Cl (13), whereas 3 undergoes oxidation at the ligand, giving a dppf-displaced complex [(HMB)Ru(CH3CN)2Cl] PF6 (14) and free dppfS2. The structures of 1, 2, 5-9, 11, 13 and 14 were established by X-ray single crystal diffraction analyses. Of these, 5 and 11 both contain a dppf-bridge between RuII centers, while 13 is a dinuclear CpRuIII disulfide-bridged complex; all the others are mononuclear. All complexes obtained were also spectroscopically characterized.
Structural dynamics and ligand mobility in carboxylate and dithiocarbamate complexes of Ru(II) containing 1,1′-bis (diphenylphosphino)ferrocene (dppf)
Lu, Xiu Lian,Ng, Sin Yee,Vittal, Jagadese J.,Tan, Geok Kheng,Goh, Lai Yoong,Hor, T.S. Andy
, p. 100 - 111 (2007/10/03)
Ruthenium(II) carboxylate and dithiocarbamate complexes containing 1,1′-bis(diphenylphosphino)ferrocene (dppf) were synthesized by displacement of triphenylphosphine in Ru(RCOO)2 (PPh3)2 (R=Me, Et, Ph) and Ru(SC(S)NEt2) 2(PPh3)2 with dppf. The complexes Ru(RCOO)2(dppf) (1a: R=Me, 1b: R=Et, 1c: R=Ph) and Ru(SC(S) NEt2)2(dppf) (3) were obtained in yields of 78-93%. The crystal structures of these complexes show coordination of the phosphorus atoms of dppf and four oxygen/sulphur atoms of carboxylate/ dithiocarbamate ligands to a Ru(II) centre with axial-bond-distorted octahedral geometry. Two pseudo-polymorphic forms of 1c were isolated and crystallographically characterized. VT-1H- and 31P {1H}-NMR spectral studies of 1a-c and 3 demonstrate mono- and bidentate exchange behaviour of the carboxylate or dithiocarbamate ligands, together with concerted twisting of the Cp rings of the dppf ligand. Complex 1c in CH3CN at room temperature gives Ru(PhCOO)2(dppf)(CH3CN)(H2O) (2), the crystal structure of which reveals two monodentate benzoate ligands around octahedral ruthenium and intramolecular inter-ligand H-bonding interaction between the coordinated H2O and the pendant carboxylate oxygen atoms. The interrelationship of crystallographic properties, structural dynamics, ligand mobility and chemical instability of these complexes will be described.
