Li^+ extraction/insertion reaction with Mg_2Mn_(0.5)Ti_(0.5)O_4 inverse spinel in the aqueous phase

An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide （Mg2Mn0.5Ti0.5O4）, were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigated by X-ray, saturation capacity of exchange, pH titration, and distribution coefficient （Kd） measurement. The acid treatments of Mg2Mn0.5Ti0.5O4 caused Mg^2＋ extractions of more than 81%, whereas the dissolutions of Mn^4＋ and Ti^4＋ were less than 10%. The experimental results proved that the acid-treated sample has a capacity of exchange 56 mg·g^-1 for Li^＋ in the solution. The chemical analysis showed that the Li^＋ extraction/insertion progressed mainly by ion-exchange mechanism and surface adsorption.

Theoretical studies of insertion reactions of singlet germylene into aryl C-C1 bond of 1-chlorobenzene

The insertion reactions of germylene into C-Cl bond of 1-chorobenzene have been explored using density functional theory. Five germylene species have been chosen for systematically studying. All the stationary points were determined at the B3LYP/ 6-311＋G （d, p） level of the theory. The results show that, the smaller the AEsT of germylene, the lower the barrier height, and the electropositive substituents on the germylene can increase the reaction activity and exothermicity of insertion into C-Cl bond of 1- chorobenzene.

Mechanism of Insertion Reactions between Silylenoid H_2SiLiF and GeH_3R(R=F,OH,NH_2):a Theoretical Study

Theoretical investigations on the insertion reaction mechanisms of three- membered-ring silylenoid H2 Si Li F with GeH 3R（R = F, OH, NH2） have been systematically carried out by combined density functional theory（DFT） and ab initio quantum chemical calculations. The geometries of all stationary points for these reactions were optimized using the B3 LYP method and then the QCISD method was used to calculate the single-point energies. The calculated results indicate that, there are one precursor complex（Q）, one transition state（TS）, and one intermediate（IM） which connect the reactants and the products along the potential energy surface. The insertion reactions of three-membered-ring silylenoid with Ge H3 R proceed in a concerted manner, forming H2RSi-Ge H3 and Li F. The calculated potential energy barriers of the three reactions are 29.17, 30.90, and 54.07 k J/mol, and the reaction energies for the three reactions are –127.05, –116.91, and –103.31 k J/mol, respectively. The insertion reactions in solvents are similar to those in vacuum. Under the same situation, the insertion reactions should occur easily in the following order： GeH 3-F GeH 3-OH GeH 3-NH2. The elucidations of the mechanism of these insertion reactions provided a new mode of silicon-germanium bond formation.

Insertion of Selenium into Zinc Carbon Bond and Application in Synthesis of Arylselenoester

Selenium was inserted into the zinc carbon bond of aryl zinc halides to form corresponding zinc selenoates. They reacted in THF-HMPA with acylhalides to afford the selenoesters in high yields.

Reaction of Bis(Methylcyclopentadienyl) Lanthanide Amido Complex with n-Hexyl isocyanate-Synthesis and Characterization of {(MeC_5H_4)_2YbOC(NPh_2)N(n-hexyl)}_2

Bis （methylcyclopentadienyl） lanthanide amido complex （MeCp） 2YbNPh2 （THF） reacted with n-hexyl isocyanate （n-nexylNCO） in 1：1 molar ratio to give {（MeC5H4）2Yb[OC（NPh2）N（n-hexyl）] }2（1）. Complex 1 was characterized by elemental analyses and X-ray diffraction. The title complex belongs to trigonal system and R-3 space group. Its unit cell parameters are a =2.9533（11） nm, b =2.9533（11） nm, c = 1.5873（6） nm, V= 11.9896（80） nm^3, Z =9, Dc= 1.562 mg·m^-3, μ = 3.536 mm^-1（Mo Kα）, F（000） =5670, R =0.034, Rw =0.064. It is a dimeric structure with two symmetrical bridged oxygen atoms. Nitrogen atom is coordinated to the ytterbium atom to form a tricyclic backbone. The coordination number of ytterbium is 9. The whole molecule shows central symmetry.

The facile insertion of β-keto sulfones to arynes:The direct preparation of polysubstituted ortho-keto benzyl sulfones

One novel carbon-carbon bond insertion reaction of arynes has been developed. By this reaction β-keto sulfones can insert the triple bond of arynes to prepare polysubstituted ortho-keto benzyl sulfones.

Theoretical Study on the Mechanism of CF_2 Reaction with CH_2O

The insertion reaction mechanism of CF2 with CH2O was investigated at the B3LYP/6-311G（d）//MP2/6-311G（d） level. The geometric conformations at each stationary point in reaction potential surface were fully optimized and the transition states were verified by intrinsic reaction coordinate （IRC） and frequency analysis. The energies of all reactants were calculated with CCSD（T）/6-311G（d）//G2MP2 methods. Results indicated that the P1 reaction route with difuoroaldehyde as product is the dominant reaction pathway, which exhibits nucleophilic character. According to NBO analysis, the starting point of insertion reaction is the interaction between carbene LP（C3） and formaldehyde π（Cl-O2）. Besides, the thermodynamic and dynamic properties of dominated reaction （1） at different temperature were studied with statistic thermodynamic method and Eyring transition state theory adjusted by Wigner means, from which the proper temperature （500- 1200 K） of reaction （1） could be estimated. Finally, the thermo- dynamic and dynamic properties of insertion reaction mechanisms （CF2, CX2 （X = Cl, Br） with CH2O） were compared and discussed.

Thermodynamic and Kinetic Studies on the SiH + XH_3 (X=N, P) Reactions

Based on the quantum chemical study of the silylidyne insertion reaction with NH3 or PH3, the general statistical thermodynamics and Eyring transition state theory with Wigner correction are used to compute the changes of thermodynamic functions, equilibrium constants, A factors and rate constants of the two reactions in the temperature range 200-2000K. The results show that both of these reactions are thermodynamically dominant at low temperatures and kinetically favored at higher temperatures. The comparison between these two reactions shows that the SiH reaction with NH3 is more exothermic than SiH with PH3, while the rate constant of SiH reaction with NH3 is lower than that of SiH with PH3 at the same temperature.

Infrared Photodissociation Spectroscopy of Ti＋（CO2）2Ar and Ti＋（CO2）n （n=3-7） Complexes

Ti＋（CO2）2Ar and Ti＋（CO2）n （n=3-7） complexes are produced by laser vaporization in a pulsed supersonic expansion. The ion complexes of interest are each mass-selected in a time- of-flight spectrometer, and studied with infrared photodissociation spectroscopy. For each complex, a sharp band in the CO stretching frequency region is observed, which confirms the formation of the OTi＋CO（CO2）~_l oxide-carbonyl species. Small OTi＋CO（CO2）~_1 complexes （n_〈5） exhibit CO stretching and antisymmetric CO2 stretching vibrational bands that are blue-shifted from those of free CO and CO2. The experimental observations indicate that the coordination number of CO and CO2 molecules around TiO＋ is five. Evidence is also observed for the presence of another electrostatic bonding Ti＋（CO2）2 structural isomer for the Ti＋（CO2）2Ar complex, which is characterized to have a bent OCO-Ti＋-OCO structure stabilized by argon coordination.

Synthesis and Crystal Structure of N-phenylthiocyano-phenyl-thioformamide bis(η_5-methylcyclopentadienyl)(tetrahydrofuran)Samarium(Ⅲ)

The insertion reaction of phenyl isothiocyanate into the Ln S bond was studied. Phenyl isothiocyanate reacted with [(CH 3C 5H 4) 2Sm(SPh)(THF)] 2 to give the title complex, (CH 3C 5H 4) 2Sm[SC(SPh)NPh](THF), in good yield, which was characterized by elemental analyses, IR, 1H NMR and X ray structural determination. The crystal structure analysis of complex shows that samarium atom is coordinated by two CH 3C 5H 4 groups, one O atom of THF, and N and S atoms from the SC(SPh)NPh ligand to form a distorted trigonal bipyramidal geometry.

Synthesis and crystal structure of（C5Me4SiMe3）[（^iPrN）2CCH2SiMe3]2Y

Reaction of（C5Me4SiMe3）Y（CH2SiMe）2（THF） with two equivalents of iPrN=C=NiPr in hexane at room temperature afforded a mixed-ligand yttrium complex（C5Me4SiMe3）（iPrN）2CCH2SiMe32Y.X-ray diffraction revealed that the center metal was nine-coordinated by one cyclopentadienyl ring and two amidinate ligands, and adopted a four-legged piano stool geometry.

Catalytic Hydrogen Transfer Reactions

Our recently studies on three types of reactions with hydrogen transfer as a key step,including catalytic asymmetric proton transfer reactions using"chiral proton transfer shuttle",catalytic B—H bond insertion containing a hydrogen atom transfer,and iron-catalyzed hydrosilylation reactions containing hydride transfer were briefly introduced.

Mechanism of Ethylene Migratory Insertion and Dimerization Catalyzed by σ-Alkyl Platinum Complexes--A DFT Study

The mechanism of ethylene insertion reactions catalyzed by cationic a-alkyl platinum complexes has been studied at the B3LYP level of density functional theory. The initial steps of the reactions proceed via the coordination of ethylene to the reactants L2Pt（II）R＋, where L2=none, （NH3）2, （CHNH）2; R=H, CH3, C2H5 in which ethylene coordinates strongly to the complexes PtCH＋ and PtC2H＋ （coordination energies （CE） are 296.52 and 229.28 kJ/mol, respectively）, while nitrogen-containing ligands decrease the energies： Pt（NH3）2CH＋ （CE： 180.04 kJ/mol）, Pt（NH3）2C2H＋ （CE： 97.86 kJ/mol）, Pt（CHNH）2 CH＋ （CE ： 176.31 kJ/mol） and Pt（CHNH）2 C2H＋ （CE： 91.00 kJ/mol）. Moreover, ethylene insertion into the Pt-alkyl bond, which is the rate-determining step, is endothermic with barrier heights for LzPtCH3（CzH4）＋ decreasing in the order： PtCH＋ （164.18 kJ/mol）〉（NH3）2 PtCH＋ （129.95 kJ/mol）〉 （CHNH）2 PtCH＋ （115.27 kJ/mol）, which has the same tendency for the ethyl case. The insertion product will continually undergo t-hydride elimination, which is exothermic. On the other hand, the effects of solvent （dichloromethane, THF and benzene） are investigated with PCM method, but the inclusion of the effects in the computations only slightly affects the results. Beside that, a complete catalytic cycle for ethylene dimerization is studied in detail and the calculations agree well with known energetic and recognized tendencies.

Gold carbene chemistry from diazo compounds

Diazo compounds are generally used as carbene precursors. Traditionally, dirhodium, copper and iron catalysts were used to decompose diazo compounds to form the key metal carbene intermediates. Recently, the gold catalysts have been developed as a unique type of metal catalyst to decompose diazo compounds. The derived gold carbene showed much different characters comparing with other transition metal carbenes. They could go through a series of cycloaddition, insertion and coupling reactions. Here, the recent progress of the gold carbene chemistry from diazo compounds was reviewed, including the scope of reactions,mechanism and synthetic applications.