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Mingfei Zhou

Publications and source records attributed to Mingfei Zhou.

At least 19 recordsLinked to original sources
PubMed2007

Matrix isolation infrared spectroscopic and theoretical study of noble gas coordinated rhodium-dioxygen complexes.

Reactions of rhodium atoms with dioxygen molecules in solid argon have been investigated using matrix isolation infrared absorption spectroscopy. The rhodium-dioxygen complexes, Rh(eta2-O2), Rh(eta2-O2)2, and Rh(eta2-O2)2(eta1-OO), are produced spontaneously on annealing. The Rh(eta2-O2) complex rearranges to the inserted RhO2 molecule under visible light irradiation. Experiments doped with xenon in argon show that the rhodium-dioxygen complexes are coordinated by one or two noble gas atoms in solid noble gas matrixes. Hence, the Rh(eta2-O2), Rh(eta2-O2)2, and Rh(eta2-O2)2(eta1-OO) molecules trapped in solid noble gas matrixes should be regarded as the Rh(eta2-O2)(Ng)2, Rh(eta2-O2)2(Ng)2, and Rh(eta2-O2)2(eta1-OO)(Ng) (Ng = Ar or Xe) complexes. The product absorptions are identified on the basis of isotopic substitution and density functional theory calculations.

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PubMed2006

Reactions of gadolinium atoms and dimers with CO: formation of gadolinium carbonyls and photoconversion to CO activated molecules.

Reactions of gadolinium atoms and dimers with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. Mononuclear Gd(CO)x (x = 1-3) and dinuclear Gd2(CO)x (x = 1, 2) gadolinium carbonyls formed spontaneously on annealing. The Gd(CO)x complexes are CO terminal-bonded carbonyls, whereas the Gd2CO and Gd2(CO)2 carbonyl complexes were characterized to have asymmetrically bridging and side-on-bonded CO, which are drastically activated with remarkably low C-O stretching frequencies. The cyclic Gd2(mu-C)(mu-O) and Gd3(mu-C)(mu-O) molecules in which the C-O triple bond is completely cleaved were also formed on annealing. The Gd2(CO)2 complex rearranged to the more stable c-Gd2(mu-O)(mu-CCO) isomer, which also has a four-membered ring structure with one CO being completely activated.

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PubMed2006

Matrix isolation infrared spectroscopic and theoretical study of NgMO (Ng = Ar, Kr, Xe; M = Cr, Mn, Fe, Co, Ni) complexes.

The matrix isolation infrared spectroscopic and quantum chemical calculation results indicate that late transition metal monoxides CrO through NiO coordinate one noble gas atom in forming the NgMO complexes (Ng = Ar, Kr, Xe; M = Cr, Mn, Fe, Co, Ni) in solid noble gas matrixes. Hence, the late transition metal monoxides previously characterized in solid noble gas matrixes should be regarded as the NgMO complexes, which were predicted to be linear. The M-Ng bond distances decrease, while the M-Ng binding energies increase from NgCrO to NgNiO. In contrast, the early transition metal monoxides, ScO, TiO, and VO, are not able to form similar noble gas atom complexes.

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PubMed2006

Reactions of early lanthanide metal atoms (Nd, Sm, Eu) with water molecules. A matrix isolation infrared spectroscopic and theoretical study.

The reactions of early lanthanide metal atoms Nd, Sm, and Eu with water molecules have been investigated using matrix isolation infrared spectroscopy and density functional calculations. The reaction intermediates and products were identified on the basis of isotopic labeled experiments and density functional frequency calculations. The ground state metal atoms react with water to form the M(H2O) and M(H2O)(2) complexes spontaneously on annealing (M = Nd, Sm, Eu). The M(H2O) complexes isomerize to the inserted HMOH molecules under red light irradiation, which further decompose to give the metal monoxides upon UV light irradiation. The Nd(H2O)(2) complex decomposes to form the trivalent HNd(OH)(2) molecule, while the Sm(H2O)(2) and Eu(H2O)(2) complexes rearrange to the divalent Sm(OH)(2) and Eu(OH)(2) molecules under red light irradiation.

Lanthanoid Series Elements↗
PubMed2006

Reactions of cerium atoms and dicerium molecules with CO: formation of cerium carbonyls and photoconversion to CO-activated insertion molecules.

Reactions of cerium with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. The cerium carbonyls CeCO and Ce2CO are produced spontaneously on annealing and they are photochemically rearranged to the CCeO and c-Ce2(mu-C)(mu-O) isomers, where Ce and Ce2 are inserted into the CO triple bond. Theoretical calculations indicate that CeCO is an end-on-bonded carbonyl with a quintet ground state, whereas Ce2CO is a rare dinuclear lanthanide carbonyl complex with CO serving as an asymmetrically bridged, side-on ligand. The CCeO molecule was theoretically characterized to have a linear structure with a singlet ground state. Evidence is also presented for the CeCO- anion and other cerium carbonyls with higher coordination numbers.

Carbon Monoxide↗
PubMed2006

Matrix isolation infrared spectroscopic and theoretical study of nickel, palladium, and platinum nitrous oxide complexes.

Binary nickel, palladium, and platinum nitrous oxide complexes Ni(NNO)x, Pd(NNO)x (x = 1, 2), and PtNNO have been produced by the reactions of laser-evaporated metal atoms with nitrous oxide in solid argon. The complexes were identified on the basis of isotopically substituted infrared absorptions as well as theoretical frequency calculations. These complexes were characterized to have structures with the terminal N atom of N(2)O bound to the metal atoms. The MNNO complexes are photosensitive and rearrange to OMNN or MO + N(2) upon ultraviolet-visible irradiation.

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PubMed2006

Methane activation by titanium monoxide molecules: a matrix isolation infrared spectroscopic and theoretical study.

Reactions of titanium monoxides with methane have been investigated using matrix isolation infrared spectroscopy and theoretical calculations. Titanium derivatives of several simple oxyhydrocarbons have been prepared and identified. The titanium monoxide molecules prepared by laser evaporation of bulk TiO2 target reacted with methane to form the TiO(CH4) complex in solid argon, which was predicted to have C3v symmetry with the oxygen atom coordinated to one hydrogen atom of the methane molecule. The complex rearranged to the CH3Ti(O)H titano-acetaldehyde molecule upon visible (lambda > 500 nm) irradiation. The titano-acetaldehyde molecule sustained further photochemical rearrangement to the CH2Ti(H)OH titano-vinyl alcohol molecule, which was characterized to be a simple carbene complex involving agostic bonding. The CH2Ti(H)OH molecule reacted with a second methane to form the (CH3)2Ti(H)OH titano-isopropyl alcohol molecule spontaneously on annealing. The (CH3)2Ti(H)OH molecule also can be produced via UV photon-induced rearrangement of the CH3Ti(O)H(CH4) complex.

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PubMed2006

Formation and characterization of the XeOO(+) cation in solid argon.

This report presents the preparation and characterization of a xenon-containing cationic radical species, XeOO+. The XeOO+ cation was produced either by co-deposition of the reactive species generated by laser ablation of different transition metals with dioxygen and xenon mixtures in excess argon or by condensation of high-frequency discharged O2/Xe/Ar mixtures at 12 K and is identified by infrared absorptions. High-level quantum chemical calculations indicate that XeOO+ has a bent structure with direct xenon-oxygen dative bonding, and the doublet ground state is much more stable than the Xe + O2+ reactants.

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PubMed2006

Noble gas-transition-metal complexes: coordination of VO2 and VO4 by Ar and Xe atoms in solid noble gas matrixes.

The matrix isolation infrared spectroscopic and quantum chemical calculation results indicate that vanadium oxides, VO2 and VO4, coordinate noble gas atoms in forming noble gas complexes. The results showed that VO2 coordinates two Ar or Xe atoms and that VO4 coordinates one Ar or Xe atom in solid noble gas matrixes. Hence, the VO2 and VO4 molecules trapped in solid noble gas matrixes should be regarded as the VO2(Ng)2 and VO4(Ng) (Ng = Ar or Xe) complexes. The total V-Ng binding energies were predicted to be 12.8, 18.2, 5.0, and 7.3 kcal/mol, respectively, for the VO2(Ar)2, VO2(Xe)2, VO4(Ar), and VO4(Xe) complexes at the CCSD(T)//B3LYP level of theory.

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PubMed2005

Coordination of ScO+ and YO+ by multiple Ar, Kr, and Xe atoms in noble gas matrixes: a matrix isolation infrared spectroscopic and theoretical study.

The combination of matrix isolation infrared spectroscopic and quantum chemical calculation results provide strong evidence that scandium and yttrium monoxide cations, ScO+ and YO+, coordinate multiple noble gas atoms in forming noble gas complexes. The results showed that ScO+ coordinates five Ar, Kr, or Xe atoms, and YO+ coordinates six Ar or Kr and five Xe atoms in solid noble gas matrixes. Hence, the ScO+ and YO+ cations trapped in solid noble gas matrixes should be regarded as the [ScO(Ng)5]+ (Ng = Ar, Kr, or Xe), [YO(Ng)6]+ (Ng = Ar or Kr) or [YO(Xe)5]+ complexes. Experiments with dilute krypton or xenon in argon or krypton in xenon produced new IR bands, which are due to the stepwise formation of the [ScO(Ar)(5-n)(Kr)n]+, [ScO(Kr)(5-n)(Xe)n]+ (n = 1-5), [YO(Ar)(6-n)(Kr)n]+ (n = 1-6), and [YO(Ar)(6-n)(Xe)n]+ (n = 1-4) complexes.

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PubMed2005

Matrix isolation infrared spectroscopic and theoretical studies on the reactions of niobium and tantalum mono- and dioxides with methane.

The reactions of niobium and tantalum monoxides and dioxides with methane have been investigated using matrix isolation infrared spectroscopic and theoretical calculations. The niobium and tantalum oxide molecules were prepared by laser evaporation of Nb(2)O(5) and Ta(2)O(5) bulk targets. The niobium monoxide molecule interacted with methane to form the ONb(CH(4)) complex, which was predicted to have C(3)(v)() symmetry with the metal atom coordinated to three hydrogen atoms of the methane molecule. The ONb(CH(4)) complex rearranged to the CH(3)Nb(O)H isomer upon 300 nm < lambda < 580 nm irradiation. The analogous OTa(CH(4)) complex was not observed, but the CH(3)Ta(O)H molecule was produced upon UV irradiation. The niobium and tantalum dioxide molecules reacted with methane to form the O(2)Nb(CH(4)) and O(2)Ta(CH(4)) complexes with C(s)() symmetry, which underwent photochemical rearrangement to the CH(3)Nb(O)OH and CH(3)Ta(O)OH isomers upon ultraviolet irradiation.

Methane↗
PubMed2005

Infrared spectra of the OH+ and H2O+ cations solvated in solid argon.

Infrared spectra of various OH+ and H2O+ isotopomers solvated in solid argon are presented. The OH+ and H2O+ cations were produced by co-deposition of H2O/Ar mixture with high-frequency discharged Ar at 4 K. Detailed isotopic substitution studies confirm the assignments of absorptions at 3054.9 and 3040.0 cm(-1) to the antisymmetric and symmetric H-O-H stretching vibrations of H2O+ and 2979.6 cm(-1) to the O-H stretching vibration of OH+. The frequencies of H2O+ solvated in solid argon are red-shifted, whereas the frequency of OH+ is blue-shifted with respect to the gas-phase fundamentals. On the basis of previous gas-phase studies and quantum chemical calculations, the OH+ and H2O+ cations solvated in solid argon may be regarded as the OH+-Ar5 and H2O+-Ar4 complexes isolated in the argon matrix.

Journal Article↗
PubMed2005

Infrared spectra and structures of the OSc(N2), OScNN, and OScNN+ complexes in solid argon.

Scandium monoxide-dinitrogen complexes-OSc(N2), OScNN, and OScNN+-have been prepared by the reactions of laser-evaporated scandium monoxide with N2 or scandium atoms with N2O in solid argon. The ground-state scandium monoxide molecule reacted with N2 to form the side-bonded OSc(N2) complex spontaneously on annealing. This complex rearranged to the end-on bonded OScNN complex upon UV irradiation. Both the OSc(N2) and OScNN complexes in solid argon can be assigned to have 2A' ' electronic ground state with Cs symmetry arising from the 2Delta first excited-state ScO. The neutral complexes can also be photoionized to the OScNN+ cation complex upon UV irradiation.

Journal Article↗
PubMed2005

Infrared spectra of phenyl nitrite and phenoxyl radical-nitric oxide complex in solid argon.

Infrared spectra and frequency assignment of two isomers of nitrobenzene, namely the phenyl nitrite C6H(5-)ONO molecule and the phenoxyl radical-nitric oxide complex C6H5O-NO, in solid argon are presented. The phenoxyl radical-nitric oxide complex was produced through UV light irradiation of nitrobenzene in low-temperature solid argon matrix. The complex rearranged to the more stable phenyl nitrite molecule on sample annealing. The aforementioned species were identified on the basis of isotopic IR studies with C6H(5-)(15)NO2 and C6D5NO2, as well as density functional theory calculations.

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PubMed2005

Reactions of germanium atoms and small clusters with CO: experimental and theoretical characterization of Ge(n)CO (n = 1-5) and Ge2(CO)2 in solid argon.

Reactions of germanium atoms and small clusters with carbon monoxide molecules in solid argon have been studied using matrix isolation infrared absorption spectroscopy. Besides the previously reported GeCO monocarbonyl, the Ge2(CO)2 and Ge(n)CO (n = 2-5) carbonyl molecules are formed spontaneously on annealing and are characterized on the basis of isotopic substitution and theoretical calculations. It is found that Ge2CO, Ge3CO, and Ge5CO are bridge-bonded carbonyl compounds, whereas Ge2(CO)2 and Ge4CO are terminal-bonded carbonyl molecules.

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PubMed2005

Formation and characterization of the (eta2-N2)Sc(H)OH and (eta1-NN)xSc(H)OH (x = 1, 2) complexes in solid argon.

Hydrido scandium hydroxide dinitrogen complexes, (eta2-N2)Sc(H)OH and (eta1-NN)xSc(H)OH (x = 1, 2), have been prepared by the reactions of laser-ablated scandium atoms with H2O/N2 mixtures in solid argon. The end-on bonded (eta1-NN)xSc(H)OH (x = 1, 2) complexes were formed spontaneously on annealing, whereas the side-bonded (eta2-N2)Sc(H)OH complex was generated on broad-band irradiation. These complexes were characterized by infrared absorption spectroscopy as well as density functional theoretical calculations.

Journal Article↗
PubMed2005

Reaction of vinyl radical with oxygen: a matrix isolation infrared spectroscopic and theoretical study.

The reaction of vinyl radical with molecular oxygen in solid argon has been studied using matrix isolation infrared absorption spectroscopy. The vinyl radical was produced through high frequency discharge of ethylene. The vinyl radical reacted with oxygen spontaneously on annealing to form the vinylperoxy radical C(2)H(3)OO with the O-O bond in a trans position relative to the C-C bond, which is characterized by O-O stretching and out-of-plane CH(2) bending vibrations at 1140.7 and 875.5 cm(-1). The vinylperoxy radical underwent visible photon-induced dissociation to the CH(2)OH(CO) complex or CH(2)OH+CO, which has never been considered in previous studies. The CH(2)OH(CO) product was predicted to be more thermodynamically accessible than the previously reported major HCO+H(2)CO channel, and is most likely produced by hydrogen atom transfer from the first-formed H(2)CO-HCO pair in solid argon.

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