1609574-91-5Relevant academic research and scientific papers
Chromium(III) catalysts based on tridentate silicon-bridged tris(diphenylphosphine) ligands for selective ethylene tri-/tetramerization
Alam, Fakhre,Chang, Qiqi,Chen, Yanhui,Dong, Chunhua,Jiang, Tao,Wang, Jiadong,Zhang, Le,Zhang, Qiyao
, p. 278 - 286 (2020)
The chromium(III) catalysts based on tridentate silicon-bridged tris(diphenylphosphine) ligands of the form RSi(CH2PPh2)3 (L1: R = Me; L2: R = Cy; L3: R = Ph) were investigated for selective ethylene tri-/tetramerization. The steric and electronic properties of the substituents attached to the silicon moiety have been observed to have a great impact on the catalytic performance of these catalysts. Single-crystal analysis, high-resolution mass spectrometry (HR-MS), and elemental analysis revealed that these complexes may adopt mononuclear tridentate coordination mode (k3-P, P, P) with Cr center. However, one of the phosphorus atoms in these complexes may act as a hemilabile donor and presumably loses its coordination with chromium in the presence of a competent donor which consequently transformed the tridentate complexes to bidentate (k2-P, P) coordination mode. Backbone modification of L1 of the precatalyst 1 via successive abstraction of methylene spacers may offer MeSi(CH2)n(PPh2)3 (L4: n = 2; L5: n = 1; L6: n = 0) type chromium(III) complexes. Ethylene oligomerization of these systems suggested that the methylene spacers may effectively tune the complex structure and catalytic performance. Precatalyst 1 and 4 respectively based on L1 and L4 deliver 70% C8 selectivity in the liquid oligomeric fraction and considerable activity under experimental conditions. DFT investigations based on catalyst 4 revealed that the catalyst may simultaneously facilitate the single and double coordination pathways for C8 formation, however, the single coordination pathway is thermodynamically more favorable for this system.
Complexes of the tripodal phosphine ligands PhSi(XPPh2)3 (X = CH2, O): Synthesis, structure and catalytic activity in the hydroboration of CO2
Aloisi, Alicia,Berthet, Jean-Claude,Genre, Caroline,Thuéry, Pierre,Cantat, Thibault
, p. 14774 - 14788 (2016)
The coordination chemistry of Fe2+, Co2+ and Cu+ ions was explored with the triphosphine and triphosphinite ligands PhSi{CH2PPh2}3 (1) and PhSi{OPPh2}3 (2), so as to evaluate the impact of the electronic properties of the tripodal phosphorus ligands on the structure and reactivity of the corresponding complexes. The synthesis and characterization of the complexes [Fe(κ3-PhSi{CH2PPh2}3)(MeCN)3][OTf]2 (3) (OTf = O3SCF3), [Fe(κ3-PhSi{OPPh2}3)(MeCN)3][OTf]2 (3′), [Co(κ2-PhSi{CH2PPh2}3)Cl2] (4), [Co(κ3-PhSi{OPPh2}3)Cl2] (4′), [Cu(κ3-PhSi{CH2PPh2}3)Br] (5) and [Cu(κ3-PhSi{OPPh2}3)I] (5′) were carried out. The crystal structures of 3, 3′, 4, 4′, and of the solvates 5·3THF and 5′·THF are reported. Complexes 3-5′ were shown to promote the catalytic hydroboration of CO2 with (9-BBN)2 (9-BBN = 9-borabicyclo[3.3.1]nonane). While the iron and cobalt complexes of the triphosphine 1 are more active than the analogous complexes with 2, the opposite trend is observed with the copper catalysts. Overall, the copper catalysts 5 and 5′ are both more reactive and more selective than the Fe and Co catalysts, enabling the formation of the acetal H2C(OBBN)2 with a high molar ratio of H2C(OBBN)2 : CH3OBBN up to 92 : 8.
Application of Hetero-Triphos Ligands in the Selective Ruthenium-Catalyzed Transformation of Carbon Dioxide to the Formaldehyde Oxidation State
Seibicke, Max,Siebert, Max,Siegle, Alexander F.,Gutenthaler, Sophie M.,Trapp, Oliver
, p. 1809 - 1814 (2019/04/25)
Due to the increasing demand for formaldehyde as a building block in the chemical industry as well as its emerging potential as feedstock for biofuels in the form of dimethoxymethane and the oxymethylene ethers produced therefrom, the catalytic transformation of carbon dioxide to the formaldehyde oxidation state has become a focus of interest. In this work, we present novel ruthenium complexes with hetero-triphos ligands, which show high activity in the selective transformation of carbon dioxide to dimethoxymethane. We substituted the apical carbon atom in the backbone of the triphos ligand platform with silicon or phosphorus and optimized the reaction conditions to achieve turnover numbers as high as 685 for dimethoxymethane. The catalytic systems could also be tuned to preferably yield methyl formate with turnover numbers of up to 1370, which in turn can be converted into dimethoxymethane under moderate conditions.
Group 8 transition metal complexes of the tripodal triphosphino ligands PhSi(CH2PR2)3 (R = Ph, iPr)
Neumeyer, Felix,Lipschutz, Michael I.,Tilley, T. Don
, p. 6075 - 6078 (2014/01/06)
A series of group 8 transition metal complexes of new tridentate phosphine ligands with Fe, Ru, and Os were prepared. The new complexes were characterized by multinuclear NMR spectroscopy and X-ray crystallography. Complexes of iron, ruthenium, and osmium with the neutral tridentate tripodal phosphine ligands PhSi(CH2PPh2)3 and PhSi(CH2PiPr 2)3 show tetrahedral coordination for iron and form cationic dimeric octahedral complexes with the heavier homologues ruthenium and osmium. Copyright
