Ti-H Bond Research Articles

Enhanced De/hydrogenation Kinetics and Cycle Stability of Mg/MgH2 by the MnOx-Coated Ti2CTx Catalyst with Optimized Ti-H Bond Stability.

MXene based catalysts can significantly enhance hydrogenation and dehydrogenation (de/hydrogenation) kinetics of Mg/MgH2, but they suffer from uncontrollable catalysts-hydrogen bond strength and structural instability. Here, we propose Tx density control of MXene-based catalysts and MnOx coating as a promising solution. The MnOx@Ti2CTx-catalyzed Mg/MgH2 can release 5.97 wt % H2 at 300 °C in 3 min and 5.60 wt % H2 at 240 °C in 15 min with an activation energy of 75.57 kJ·mol-1. In addition, the samples showed excellent de/hydrogenation-cycle stability, and the degradation of hydrogen storage capacity is negligible even after 100 cycles. DFT calculations combined with XPS analysis showed that the Tx defect on the surface of the MnOx@Ti2CTx catalyst could optimize the strength of the Ti-H bond, accelerating both hydrogen dissociation and diffusion processes. The catalyst's surface properties were protected by the MnOx coating, achieving high chemical and catalytic stability. These findings offer a strategy for surface structure optimization and protection of MXene-based catalysts, realizing controllable catalyst-hydrogen bond strength.

Converging Stereodivergent Reactions - Highly Stereoselective Formal anti-Markovnikov Addition of H2O to Mixtures of Olefins.

We describe a highly diastereo- and enantioselective two-step formal anti-Markovnikov addition of H2O to diastereomeric mixtures of olefins. Our approach relies on the highly enantioselective syn-specific Shi-epoxidation of both olefin isomers and a stereoconverging epoxide hydrosilylation featuring a directional isomerization step via a configurationally labile radical intermediate that is reduced by a syn-selective intramolecular hydrogen atom transfer from a Ti-H bond.

Adsorption of a water molecule on the surface of neutral and charged titanium clusters: Tin-H2O, Tin+1-H2O, Tin-1-H2O, n ≤ 9

Adsorption of a water molecule on the surface of neutral and charged titanium, Tin0, ±1 H2O, n ≤ 9, clusters was studied in this work using density functional theory, BPW91-D2, all-electron calculations. Water adsorption is crucial for understanding the nascent solvation of Tin and H-O bond activation. Computed Tin0,±1 ground states, GS, allow a characterization of the structural, electronic, and energetic properties. Compact forms appear for the Tin0,±1, n ≤ 9 GS, and the estimated ionization energies (IE), electron affinities (EA) and binding energies (D0) follow the trends of available experimental results. The most stable clusters are Ti4+1, Ti50, -1, Ti70, ±1, and Ti90, ± 1, being in accord with the measured D0 for the cations. Overall, the cations show larger D0 that neutral and anions: D0(Tin+) > D0 (Tin) > D0(Tin-). Further, the IE are reduced by water adsorption on the Tin clusters, this being due to delocalization effects, through the network of the Ti–Ti and Ti–O bonds, of the most external valence electrons of Tin-H2O. For Tin+H2O, the lowest D0 occur at n = 4, 7, and 9, with maximums at n = 5 and 8, the highest D0 is for n = 1; being different from those of bare Tin+. Metal-oxygen Ti-O bond and Ti-H bond interactions account for the adsorption of water on Tin0,±1, which occurs on a metal atom of a triangular Ti3 face. In the Ti-O and Ti-H bond pattern, the metal atom is roughly placed in between the O and H atoms, originating agostic bonds, which produce H-O bond activation, being larger in the Tin––H2O anions. Thus, the titanium clusters may show catalytic behavior in their interaction with water molecules.

Wet-chemistry hydrogen doped TiO2 with switchable defects control for photocatalytic hydrogen evolution

<h2>Summary</h2> Hydrogen has a remarkably flexible chemistry in oxides. We show that the introduction of H into simple TiO₂ leads to greatly enhanced photocatalytic properties, and specifically yields a 60 times enhancement of photocatalytic hydrogen evolution activity over commercial rutile. The hydrogenated TiO₂ (H-TiO₂) is synthesized by a new one-step wet-chemistry approach yielding switchable defect via controlled annealing. As-prepared H-TiO₂ has Ti-H bonds in the lattice from replacement of oxygen by hydrogen atoms. The Ti-H bonds are converted to oxygen vacancies by loss of H₂O with Ar annealing. Oppositely, Ti-H defects are healed by Ti-O with O₂ annealing. The strongly enhanced photocatalytic activity is associated with increased visible light absorption and effective separation of photogenerated carriers. This work provides a new and powerful approach for the preparation of hydrogenated titanium dioxide with switchable defect control, and striking improvement of photocatalytic activity.

First-principles study on hydrogen storage properties of Ti8C6 cluster

The geometric structure, energy gaps of molecular orbital and hydrogen absorb capacities of Ti8C6 clusters are investigated by first-principles based on density functional theory. The results show that the bond length of hydrogen molecules decrease and the Ti-H bond length of Ti8C6(H2)n clusters increase with the increase of hydrogen molecules adsorbed by Ti8C6 from 8 to 40. Moreover, the Ti8C6(H2)40 cluster not only exhibits strong stability according to energy gap analysis, but also absorbs 40 hydrogen molecules with gravimetric density of 15.05 wt%, which will be considered as a candidate material for hydrogen absorption.

Exploring the novel structure, transportable capacity and thermodynamic properties of TiH 2 hydrogen storage material

We apply the first-principles calculations to study the structure, elastic modulus, Debye temperature and heat capacity of four TiH2. The results show that one new orthorhombic (Pnma) TiH2 is predicted. The tetragonal (I4mmm) TiH2 is more stable than the cubic (Fm-3m) TiH2. Compared to MgH2, TiH2 shows the strong deformation resistance. TiH2 dihydrides exhibit the strong bulk modulus compared to MgH2. The electronic structure shows that the high elastic modulus of TiH2 is determined by the Ti-H bonds. The Debye temperature of cubic (Fm-3m) and tetragonal (I4mmm) TiH2 is larger than the orthorhombic TiH2. The heat capacity follows the order of orthorhombic > cubic > tetragonal.

Theoretical investigation of Ti and Ni co-doping on the anti-disproportionation ability of ZrCo alloy

First-principles calculations are utilized to investigate the effect of Ti and Ni co-doping on the anti-disproportionation ability of ZrCo alloy. In Ti and Ni co-doped ZrCoH3, the Ti-H(8e) bond shows a strong ionic feature and the Ni-H(8e) bond exhibits covalent bonding characteristic. Judged by the Zr-H(8e) bond length, the size of the 8e site and H diffusion barrier out of the 8e site in ZrCoH3, it can be concluded that the Ti + Ni co-doping can impair the anti-disproportionation ability of Ti doping in ZrCo alloy, which uncovers the mechanism of the negative effect of Ni on the Ti-doped ZrCo alloy found in the previous experimental results.

Revealing the Relationship between Photocatalytic Properties and Structure Characteristics of TiO2 Reduced by Hydrogen and Carbon Monoxide Treatment.

Reduction is considered to be an effective method to improve the photocatalytic activity of TiO2 ; however, the underlying relationship between structure and photocatalytic performance has not been adequately unveiled to date. To obtain insights into the effect of structure on photocatalytic activity, two types of reduced TiO2 were prepared from CO (CO-TiO2 ) and H2 (H-TiO2 ). For H-TiO2 , Ti-H bonds and oxygen vacancies are formed on the surface of H-TiO2 , which results in a more disordered surface lattice. However, for CO-TiO2 , more Ti-OH bonds are formed on the surface and more bulk oxygen vacancies are introduced; the disorder layer of CO-TiO2 is relatively thin, owing to most surface vacancies being filled by Ti-OH bonds. Under simulated solar irradiation, the photocatalytic H2 evolution rate of CO-TiO2 reaches 7.17 mmol g-1 h-1 , which is 4.14 and 1.50 times those of TiO2 and H-TiO2 , respectively. The photocatalytic degradation rate constant of methyl orange on CO-TiO2 is 2.45 and 6.39 times those on H-TiO2 and TiO2 . The superior photocatalytic activity of CO-TiO2 is attributed to the effective separation and transfer of photogenerated electron-hole pairs, due to the synergistic effects of oxygen vacancies and surface Ti-OH bonds. This study reveals the relationship between the photocatalytic properties and structure, and provides a new method to prepare highly active TiO2 for H2 production and environmental treatment.

Ab-initio study of hydrogen mobility in the vicinity of MgH2[sbnd]Mg interface: The role of Ti and TiO2

Doping of MgH2 with transition metals and their oxides is well-known procedure to improve its hydrogen (de)sorption properties, namely to lower the temperature of desorption and to achieve the kinetics speedup. In order to assess the influence Ti and TiO2 doping has on H mobility and to characterize structurally and electronically observed differences, MgH2Mg interface doped with both Ti and TiO2 have been studied using ab-initio interface molecular dynamics and bulk calculations. Results suggest different mechanisms of MgH2 structure destabilization. The presence of dopants significantly stabilize MgH2Mg interface, which is confirmed by work of adhesion computation. Calculated formation energies show that interface system with doped TiO2 is more stable. In terms of H mobility, molecular dynamics simulations confirm that Ti doping is more effective than TiO2 in lowering the desorption temperature. The mobility of hydrogen atoms close to dopant is much higher in the case of Ti than in the case of TiO2. Electronic structure characterization reveals that oxygen atoms with high electron affinity forms more pronounced ionic bonding with Ti and the other neighbor Mg atoms. This in turn cause a shorter TiH bonds in first coordination than in the case of Ti doping and further reduction of H atoms mobility. This is in accordance with molecular dynamics predictions.

Matrix Infrared Spectra and Quantum Chemical Calculations of Ti, Zr, and Hf Dihydride Phosphinidene and Arsinidene Molecules.

Laser ablated Ti, Zr, and Hf atoms react with phosphine during condensation in excess argon or neon at 4 K to form metal hydride insertion phosphides (H2P-MH) and metal dihydride phosphinidenes (HP═MH2) with metal phosphorus double bonds, which are characterized by their intense metal-hydride stretching frequencies. Both products are formed spontaneously on annealing the solid matrix samples, which suggests that both products are relaxed from the initial higher energy M-PH3 intermediate complex, which is not observed. B3LYP (DFT) calculations show that these phosphinidenes are strongly agostic with acute H-P═M angles in the 60° range, even smaller than those for the analogous methylidenes (carbenes) (CH2═MH2) and in contrast to the almost linear H-N═Ti subunit in the imines (H-N═TiH2). Comparison of calculated agostic and terminal bond lengths and covalent bond radii for HP═TiH2 with computed bond lengths for Al2H6 finds that these strong agostic Ti-H bonds are 18% longer than single covalent bonds, and the bridged bonds in dialane are 10% longer than the terminal Al-H single bonds, which show that these agostic bonds can also be considered as bridged bonds. The analogous arsinidenes (HAs═MH2) have 4° smaller agostic angles and almost the same metal-hydride stretching frequencies and double bond orders. Calculations with fixed H-P-Ti and H-As-Ti angles (170.0°) and Cs symmetry find that electronic energies increased by 36 and 44 kJ/mol, respectively, which provide estimates for the agostic/bridged bonding energies.

Synergetic effects in novel hydrogenated F-doped TiO2 photocatalysts

The synergistic effect between fluorine and hydrogen in hydrogenated F-doped TiO2 photocatalysts is evaluated for the photocatalytic degradation of atrazine. The interaction between fluorine and hydrogen species in hydrogenated F-doped TiO2 overcomes the limitations of individual F-doped TiO2 and hydrogenated TiO2 photocatalyst properties. Hydrogenated F-doped TiO2 is photo-active under UV, visible and infrared light illumination with efficient electrons and holes separations. The optimized concentration of surface vacancies and Ti3+ centers coupled with enhanced surface hydrophilicity facilitates the production of surface-bound and free hydroxyl radicals. The surface of the catalyst contains TiF, TiOH, TiOvacancy and TiH bonds as evidenced by XPS, Raman, FTIR and HR-TEM analysis. This combination also triggers the formation of new Ti3+ occupied states under the conduction band of hydrogenated F-doped TiO2. Moreover, the change in the pore structure from cylindrical to slits and larger surface area facilitates surface charge interactions. The thermal stability is also enhanced and a single anatase phase is obtained. The size of the particles of hydrogenated F-doped TiO2 is also uniform with defined and homogeneous crystal structure. This synergetic effect between fluorine and hydrogen opens up new alternatives in improving the properties of TiO2 and its photocatalytic activity.

Ligand-Controlled CO2 Activation Mediated by Cationic Titanium Hydride Complexes, [LTiH](+) (L=Cp2 , O).

CO2 activation mediated by [LTiH](+) (L=Cp2 , O) is observed in the gas phase at room temperature using electrospray-ionization mass spectrometry, and reaction details are derived from traveling wave ion-mobility mass spectrometry. Wheresas oxygen-atom transfer prevails in the reaction of the oxide complex [OTiH](+) with CO2 , generating [OTi(OH)](+) under the elimination of CO, insertion of CO2 into the metal-hydrogen bond of the cyclopentadienyl complex, [Cp2 TiH](+) , gives rise to the formate complex [Cp2 Ti(O2 CH)](+) . DFT-based methods were employed to understand how the ligand controls the observed variation in reactivity toward CO2 . Insertion of CO2 into the Ti-H bond constitutes the initial step for the reaction of both [Cp2 TiH](+) and [OTiH](+) , thus generating formate complexes as intermediates. In contrast to [Cp2 Ti(O2 CH)](+) which is kinetically stable, facile decarbonylation of [OTi(O2 CH)](+) results in the hydroxo complex [OTi(OH)](+) . The longer lifetime of [Cp2 Ti(O2 CH)](+) allows for secondary reactions with background water, as a result of which, [Cp2 Ti(OH)](+) is formed. Further, computational studies reveal a good linear correlation between the hydride affinity of [LTi](2+) and the barrier for CO2 insertion into various [LTiH](+) complexes. Understanding the intrinsic ligand effects may provide insight into the selective activation of CO2 .

The origin of the chemoselectivity in the Cp2TiCl2/MAO catalyst for the polymerization of 1,3-butadiene explored by Density Functional Theory

A large variety of Ti catalysts are involved in the polymerization of ethylene, propylene, 1,3 butadiene and other di-olefins. In the present work we deal with the reaction mechanism of Cp2TiCl2 which in combination with methylaluminoxane (MAO) as alkylating agent produces a predominantly cis-1,4 poly(butadiene) (cis content of about 80%). Different reaction mechanisms have been proposed in the literature: the η5 coordination of both Cp ligands, the formation of a carbene-like structure containing a Ti-H bond, and the loss of one of the Cp ligands during the polymerization process. We investigate in a systematic way all the proposed pathways by means of Density Functional Theory calculations and Car–Parrinello molecular dynamics. Calculations can rule out several catalytic pathways that are either thermodynamically or kinetically disfavored. The resulting proposed energy profiles and free energies differences suggest that the only mechanism compatible with the formation of cis-1,4 poly(butadiene) is the loss of a Cp ring during the polymerization process, as previously suggested by Miyazawa and Suzuki [A. Miyazawa, Y. Suzuki, J. Chem. Res. (S) (2002) 503]. Within the proposed pathway we have also identified the catalytic step responsible for the chemoselectivity of the growing chain. The calculated ratio between the occurrence of 1,2 and cis-1,4 in the produced polymer is in fair agreement with experiments, which gives predominantly cis-1,4 polybutadiene.

The Role of the Surface Coverage on the Structural and the Electronic Properties of TiO2 Nanocrystals

AbstractThe titanium dioxide (TiO2) complexes are widely investigated for their striking and multipurpose capabilities. The TiO2 key feature lies in its photocatalytic activity for several reactions of social (bioengineering, environmental and artistic protection, pollution containment) and commercial (photovoltaic, alternative-energy, gas sensing) interests. The possibility to enhance specific reactions at the nanoscale by a fine tuning of the nano-sized single crystals properties boosted in the last decade the scientific research. Thus a theoretical understanding of the fundamental properties of TiO2 nanocrystals became necessary to predict and expedite the experimental effords. We present here a characterization of TiO2 0D nanoclusters and 1D nanowires in the framework of ab initio DFT calculations. Based on both theoretical and experimental evidences we defined a stoichiometric TiO2 NC by modifying a perfect bipyramidal morphology and then used this NC as a chain repetition unit in the NW. We analyzed the effect of the surface coverage by functionalizing dangling bonds with simple adsorbates (dissociated water and hydrogens) modeling two acidic environments. These terminations are important to model the basical interactions of TiO2 nanosystems with the hydration sphere, which is always found to surround the nanosamples and toaffect their photocatalytic activity. We thus address the electronic reorganization and the surface weight in determining the global features of the nanostructures. The structural reconstruction is found to depend on the surface coverage and the experimental evidences on the structural variations can be explained by a topological analysis of the Ti-O bonds. Quantum confinement effects in the electronic properties are observed through the bandgap widening and the discretization of the energy distribution, but the surface competes to determine the energy dispersion of the electronic levels. The hydrogenated nanocrystals do show occupied levels at the bottom of the coduction bands, thus leading to metallic nanowires in one dimension. Whereas in the hydrogenated cluster such levels present a localized charge distribution with respect to the whole structure and they are also similar for the atomic orbital character and energy position to the defect states obtained by oxygens desorption. From the analysis of the electronic density of states we found that Ti-H bonds induce in-gap states above the valence bands, whereas hydration leads to occupied states that shift the valence bands to lower binding energies. Formation energy calculations reveal that surface hydration leads to the most stable nanocrystals, in agreement with the experimental findings that water coverage stabilizes the surface.

Theoretical Study of C−H and N−H σ-Bond Activation Reactions by Titinium(IV)-Imido Complex. Good Understanding Based on Orbital Interaction and Theoretical Proposal for N−H σ-Bond Activation of Ammonia

The C-H sigma-bond activation of methane and the N-H sigma-bond activation of ammonia by (Me3SiO)2Ti(=NSiMe3) 1 were theoretically investigated with DFT, MP2 to MP4(SDQ), and CCSD(T) methods. The C-H sigma-bond activation of methane takes place with an activation barrier (Ea) of 14.6 (21.5) kcal/mol and a reaction energy (DeltaE) of -22.7 (-16.5) kcal/mol to afford (Me3SiO)2Ti(Me)[NH(SiMe3)], where DFT- and MP4(SDQ)-calculated values are given without and in parentheses, respectively, hereafter. The electron population of the CH3 group increases, but the H atomic population decreases upon going to the transition state from the precursor complex, which indicates that the C-H sigma-bond activation occurs in heterolytic manner unlike the oxidative addition. The Ti atomic population considerably increases upon going to the transition state from the precursor complex, which indicates that the charge transfer (CT) occurs from methane to Ti. These population changes are induced by the orbital interactions among the d(pi)-p(pi) bonding orbital of the Ti=NSiMe3 moiety, the Ti d(z2) orbital and the C-H sigma-bonding and sigma*-antibonding orbitals of methane. The reverse regioselective C-H sigma-bond activation which leads to formation of (Me3SiO)2Ti(H)[NMe(SiMe3)] takes place with a larger Ea value and smaller exothermicity. The reasons are discussed in terms of Ti-H, Ti-CH3, Ti-NH3, N-H, and N-CH3 bond energies and orbital interactions in the transition state. The N-H sigma-bond activation of ammonia takes place in a heterolytic manner with a larger Ea value of 19.0 (27.9) kcal/mol and considerably larger exothermicity of -45.0 (-39.4) kcal/mol than those of the C-H sigma-bond activation. The N-H sigma-bond activation of ammonia by a Ti-alkylidyne complex, [(PNP)Ti(CSiMe3)] 3 (PNP = N-[2-(PH2)2-phenyl]2-]) ,was also investigated. This reaction takes place with a smaller E(a) value of 7.5 (15.3) kcal/mol and larger exothermicity of -60.2 (-56.1) kcal/mol. These results lead us to predict that the N-H sigma-bond activation of ammonia can be achieved by these complexes.

Unprecedented flexibility of the &gt;TiSi&lt; group for the addition of H2

We show using DFT calculations that a coordinatively unsaturated >Ti=Si< group exhibits an unprecedented flexibility for the reversible addition of dihydrogen. The H2 attachment may lead to a variety of hydrogenated species (near-equivalent in energy), which contain three-center Ti...H...Si and terminal Ti-H and Si-H bonds. The >Ti=Si< moiety also exhibits a particularly low electronic barrier for heterolytic H2 attachment (approximately 0.0 eV) and beneficial thermodynamics of this process. One important path leads to the kinetically preferred H-Ti...H...Si isomer (at -0.5 eV with respect to the substrates, denoted II), which is capable of a subsequent low-barrier H2 release. Chemically pre-engineered compounds containing the >Ti=Si< grouping might be used for efficient H2 transfer catalysis in organic and inorganic hydrogenations, and for charging/discharging of the hydrogen storage materials.

The Ti 2 H 2 molecule: terminal or bridging hydrogens ?

Density functional calculations carried out for Ti2H2 show that several structures are thermodynamically stable with respect to Ti2+H2. The ground state of Ti2H2 is found to be 3B1 and it involves two hydrogen bridges in a nonplanar C 2 v arrangement. The 1A1 state and other triplet states of the bridging structure are only a few kilocalories per mole above the ground state. The 1Σ g + state, which corresponds to the Ti analogue of acetylene, is energetically less favored than the bridging structure but it is still bound relative to Ti2+H2. Results are also presented for the Ti2H molecule. Both bridging and terminal isomers are found to be very stable due to the formation of strong covalent Ti-H bonds. A comparison of the calculated harmonic vibrational frequencies and IR intensities of Ti2H2 and Ti2H isomers with the spectra from matrix isolation IR studies on Ti x /H2 indicates that these molecules may have been produced in low-temperature reactions.

Reactivity of tervalent titanium compounds (.eta.5-C5Me5)2TiR (R = Me, Et): insertion versus .beta.-hydrogen transfer and olefin extrusion. Preparation of the paramagnetic titanium alkoxide, iminoacyl, acyl, vinyl, and azomethide complexes (.eta.5-C5Me5)2TiX and oxidation of these with PbCl2 to the diamagnetic tetravalent derivatives (.eta.5-C5Me5)2Ti(X)Cl

The paramagnetic, tervalent titanium alkyls Cp*2TiR (1, R = Me; 2, R = Et) were compared in their behavior toward a range of reactive molecules. These 15-electron, d1 systems appear to be weak Lewis acids, reluctant to form adducts. Only for 1 and Me3CC=N could an instable adduct Cp*2TiR.L be isolated. With active-hydrogen-containing substrates HX (X = O2C(H)Me2, OEt, C=CMe), Cp*2TiX and RH were produced. Polar, unsaturated molecules like Me3CN=C, CO, and paraformaldehyde inserted to give Cp*2Ti{eta-2-C(R)=NCMe3}, Cp*2Ti{eta-2-C(O)R}, and Cp*2TiOCH2R for both 1 and 2. Apolar unsaturated substrates did not insert into the Ti-C bond with the exception of MeC=CMe, which reacted with 1 to produce the vinyl compound Cp*2TiC(Me)=CMe2. A striking difference between 1 and 2 was found in their reaction with CO2, Me3CC=N, Me2C=O, and RC=CR1 (R, R1 = Me, Ph). While 1 either gave a normal insertion (CO2 and MeC=CMe) or adducts (Me2CO, Me3CC=N) or did not react (PhC=CPh), 2 lost ethene and gave compounds that appared to be products of insertion into a Ti-H bond, Cp*2TiO2CH, Cp*2TiN=C(H)CMe3, Cp*2TiOC(H)Me2, and Cp*2TiC(R)=C(H)R1. Facile beta-hydrogen transfer from the ethyl ligands was also observed in the reaction of 2 with olefins CH2=CHR (R = Me, Ph) to give ethene and Cp*2TiCH2CH2R. This reaction is reversible and equilibrium constants could be determined. Ground-state differences between 2 and Cp*2TiCH2CH2R were found to be 9 (2) (R = Me) and (2) kJ.mol-1 (R = Ph). Isotope-labeling experiments showed that liberation of ethene and formation of the new insertion products proceed via an intermediate hydride, Cp*2TiH. The kinetic preference for insertion of an unsaturated substrate into the Ti-H bond relative to insertion into the Ti-C bond, in combination with a rapid equilibrium between ethene elimination and reinsertion causes 2 to react in most cases as a hydride, and explains the striking difference in reactivity between 1 and 2. The products of 1 and 2 with various substrates were also characterized as their monochloride derivative Cp*2Ti(R)Cl after quantitative oxidation with PbCl2. Comparison of spectroscopic data gives information about the specific coordination of ligand R in both Cp*2TiR and Cp*2Ti(R)CI and shows that the Lewis acidity of the metal center increases substantially on oxidation to Ti(IV).

ChemInform Abstract: A Theoretical Study of Olefin lnsertions into Ti‐C and Ti‐H Bonds.

Chemischer InformationsdienstVolume 17, Issue 7 Physical Organic Chemistry ChemInform Abstract: A Theoretical Study of Olefin lnsertions into Ti-C and Ti-H Bonds. H. FUJIMOTO, H. FUJIMOTOSearch for more papers by this authorT. YAMASAKI, T. YAMASAKISearch for more papers by this authorH. MIZUTANI, H. MIZUTANISearch for more papers by this authorN. KOGA, N. KOGASearch for more papers by this author H. FUJIMOTO, H. FUJIMOTOSearch for more papers by this authorT. YAMASAKI, T. YAMASAKISearch for more papers by this authorH. MIZUTANI, H. MIZUTANISearch for more papers by this authorN. KOGA, N. KOGASearch for more papers by this author First published: February 18, 1986 https://doi.org/10.1002/chin.198607069AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume17, Issue7February 18, 1986 RelatedInformation

水素化物，Ti&lt;SUB&gt;5&lt;/SUB&gt;Si&lt;SUB&gt;3&lt;/SUB&gt;H(D)&lt;SUB&gt;1&amp;minus;&lt;I&gt;x&lt;/I&gt;&lt;/SUB&gt;中の水素および重水素の存在状態

A structure analysis of Ti5Si3D0.9 has been carried out to determine the deuterium trap sites by neutron powder diffraction with the Rietveld profile analysis. It is revealed that the deuterium atoms are located at octahedral (2b) sites surrounded by six Ti atoms in the crystal structure of Ti5Si3D0.9, space group P63/mcm. Local vibration spectra of hydrogen in Ti5Si3H0.83 measured by neutron inelastic scattering support this result; the energy eigenvalue of the primary vibration mode is found at 7.53 kJ/mol (78 meV). The hole radius and the spring constant of the Ti-H(D) bond are discussed.