17520-19-3Relevant academic research and scientific papers
H2 storage materials (22KJ/mol) using organometallic Ti fragments as σ-H2 binding sites
Hamaed, Ahmad,Trudeau, Michel,Antonelli, David M.
, p. 6992 - 6999 (2008)
Low-coordinate Ti (III) fragments with controlled geometries designed specifically for σ-H2 binding were grafted onto mesoporous silica using tri- and tetrabenzyl Ti precursors. The hydrogen storage capacity was tested as a function of precursor and precursor loading level. At an optimal loading level of 0.2 mol equiv tetrabenzyl Ti the total storage capacity at -196°C was 21.45 wt % and 34.10 kg/m3 at 100 atm, and 3.15 wt % and 54.49 kg/m3 for a compressed pellet under the same conditions. The adsorption value of this material was 1.66 wt %, which equates to an average of 2.7 H2 per Ti center. The adsorption isotherms did not reach saturation at 60 atm, suggesting that the theoretical maximum of 5 H2 per Ti in this system may be reached at higher pressures. The binding enthalpies rose with surface coverage to a maximum of 22.15 kJ/mol, which is more than double that of the highest recorded previously and within the range predicted for room temperature performance. The adsorption values of 0.99 at -78°C and 0.69 at 25°C demonstrate retention of 2.4 H2 and 1.1 H2 per Ti at these temperatures, respectively. These findings suggest that Kubas binding of H2 may be exploited at ambient temperature to enhance the storage capacities of high-pressure cylinders currently used in hydrogen test vehicles.
Optimization of hydrogen storage capacity in silica-supported low valent Ti systems exploiting Kubas binding of hydrogen
Hamaed, Ahmad,Hoang, Tuan K.A.,Trudeau, Michel,Antonelli, David M.
, p. 2793 - 2800 (2009)
Silica-based materials grafted with low valent Ti fragments for Kubas-type binding of hydrogen were optimized for hydrogen adsorption capacity by varying the surface area, pore size, loading levels, and type of organometallic precursor. All materials were
Titanium-Catalyzed Intermolecular Hydroaminoalkylation of Alkenes with Tertiary Amines
Geik, Dennis,Rosien, Michael,Bielefeld, Jens,Schmidtmann, Marc,Doye, Sven
supporting information, p. 9936 - 9940 (2021/03/31)
The first cationic titanium catalyst system for the intermolecular hydroaminoalkylation of alkenes with various tertiary alkylamines is presented. Corresponding reactions which involve the addition of the α-C?H bond of a tertiary amine across the C?C double bond of an alkene take place at temperatures close to room temperature with excellent regioselectivity to deliver the branched products exclusively. Interestingly, for selected amines, α-C?H bond activation occurs not only at N-methyl but also at N-methylene groups.
Fast Titanium-Catalyzed Hydroaminomethylation of Alkenes and the Formal Conversion of Methylamine
Bielefeld, Jens,Doye, Sven
supporting information, p. 6138 - 6143 (2020/03/13)
The scientific interest in catalytic hydroaminoalkylation reactions of alkenes has vastly increased over the past decade, but these reactions have struggled to become a viable option for general laboratory or industrial use because of reaction times of several days. The titanium-based catalytic system introduced in this work not only reduces the reaction time by several orders of magnitude, into the range of minutes, but the catalyst is also demonstrated to be easily available from common starting materials, at a cost of approximately 1 € per millimole of catalyst. We were also able to formally perform C?H activation of methylamine and achieve coupling to a broad variety of alkenes, through silyl protection of the amine and simple deprotection by water.
METAL HYDRAZIDE MATERIALS
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Page/Page column 30, (2010/07/09)
The present invention provides the following new polymers which are useful for hydrogen storage: (i) a polymer comprising -[MN2]- as a repeating unit, wherein M is selected from the group consisting Sc, Ti, V, Cr, Mn, Fe, Co, Zr, Nb, Mo, and mixtures thereof; and (ii) a polymer comprising -[M2N3]- as a repeating unit, wherein M is selected from the group consisting Sc, Ti, V, Cr, Mn, Fe, Co, Zr, Nb, Mo, and mixtures thereof.
Polymerization of α-olefins and butadiene and catalytic cyclotrimerization of 1-alkynes by a new class of group IV catalysts. Control of molecular weight and polymer microstructure via ligand tuning in sterically hindered chelating phenoxide titanium and zirconium species
Van Der Linden, Arjan,Schaverien, Colin J.,Meijboom, Nico,Ganter, Christian,Orpen, A. Guy
, p. 3008 - 3021 (2007/10/02)
A new class of homogeneous catalysts for olefin oligo-polymerization is reported. These titanium or zirconium sterically hindered chelating alkoxide complexes were prepared by reaction of M(CH2Ph)4 (M = Ti, Zr) or Zr(CH2Ph)2Cl2(OEt2)2 with the appropriate biphenol or binaphthol, or by reaction of TiCl4 with the diol. Using these methodologies, a range of binaphthoxide and biphenoxide catalysts with varying steric hindrance have been prepared: {1,1′-(2,2′,3,3′-OC10H5SiR 3)}2ZrCl2 {R3 = Me3 (1); R3 = MePh2 (2); R3 = Ph3 (3)}, {1,1′-(2,2′,3,3′-OC10H5SiMe 3)}2Ti(CH2Ph)2 (4), {1,1′-(2,2′,3,3′-OC10H5SiMePh 2)}2Zr(CH2Ph)2 (5), (1,1′-(2,2′,3,3′-OC10H5-SiPh 3)}2M(CH2Ph)2 {M = Ti (7), M = Zr (8)}, 2,2′-S(4-Me,6-tBuC6H2O) 2MX2 {MX2 = TiCl2 (10); MX2 = ZrCl2 (11); MX2 = Ti(CH2Ph)2 (12)}, {2,2′-S(4-Me,6-tBuC6H2O) 2}2Ti (13), 2,2′-(4,6-tBu2C6H2O) 2MX2 {MX2 = Ti(CH2-Ph)2 (14); MX2 = ZrCl2(THF)2 (15)}, {2,2′-(4-OMe,6-tBuC6H2O)2}2Ti (16), 2,2′-(4-OMe66-tBuC6H2O) 2Ti(CH2Ph)2 (17)}, 2,2′-CH2(4-Et,6-tBuC6H2O) 2TiX2 {X = CH2Ph (18), X = Cl (19), and {2,2′-CH2(4-Et,6-tBuC6H 2O)2}2Ti (20). This class of L2MCl2 systems can be regarded as being analogous to the well-documented range of Group IV metallocenes. Alkylation of (O-O)ZrCl2 ((O-O = chelating phenoxide) allowed access to other alkyl species. Therefore, reaction of 3 with MeLi or Me3SiCH2Li afforded {1,1′-{2,2′,3,3′-OC10H5SiPh 3}2ZrX2 {X = Me (6); X = CH2SiMe3 (9)}, respectively. The X-ray crystal structure of 17 is reported. At 213 K, 17·1/2OEt2 has space group P1? and unit cell dimensions a = 8.737(9) A?, b = 11.840(10) A?, c = 17.135(17) A?, α = 98.28(7)°, β = 90.53(8)°, γ = 101.38(7)°, μ(Mo Kα) = 2.88 cm-1. Attempts to prepare analogous sterically hindered binaphthiolates were thwarted by the absence of known sterically hindered chelating binaphthiols. Synthetic routes to such ligands were attempted albeit without success. The chelating phenoxide and binaphthoxide titanium and zirconium species, in the presence of an aluminum cocatalyst are active for the oligo-polymerization of α-olefins. For the polymerization of ethylene, rates of up to 4740 kg of PE/mol of catalyst·h (100 kg/g of Ti·h) were obtained. They are active for the polymerization of butadiene and the catalytic cyclotrimerization of terminal acetylenes to 1,2,4- and 1,3,5-trisubstituted benzenes. This ratio of benzenes is dependent on the steric bulk of the ancillary binaphthol ligands. Steric modifications also have a clear influence on the degree of 1-hexene polymerization as well as the tacticity of poly-(1-hexene). In particular, the chelating alkoxide ligand framework can induce stereoregularity. For 1 and 2, with methylaluminoxane as cocatalyst, regioregular and stereospecific polymerization of 1-hexene is observed to give high molecular weight isotactic polyhexene. Related ligand-dependent differences in polymer microstructure are observed in the polymerization of butadiene. Cationic complexes have been synthesized. [(C10H5SiPh3O)2Zr(CH 2-Ph)]BPh4 (21), and zwitterionic (C10H5SiPh3O)2Zr(CH 2Ph)(η6-PhCH2)B(C6F 5)3 (22) were made by treatment of 8 with [PhNMe2H]BPh4 and B(C6F5)3, respectively. They are active for the polymerization of ethylene.
