Covalent Bonding Between Be and CO in BeOCO with a Surprisingly High Antisymmetric OCO Stretching Vibration.

The cationic complex BeOCO is produced in a solid neon matrix. Infrared absorption spectroscopic study shows that it has a very high antisymmetric OCO stretching vibration of 2418.9 cm, which is about 71 cm blue-shifted from that of free CO.

Boron-Mediated Carbon-Carbon Bond Cleavage and Rearrangement of Benzene Forming the Borepinyl Radical and Borole Derivatives.

The reaction of atomic boron with benzene in solid neon has been investigated by matrix isolation infrared spectroscopy with isotopic substitutions as well as quantum chemical calculations. The reaction is initiated by boron atom addition to benzene in forming an η-(1, 4) π adduct (). A borepinyl radical () formed by C-C bond insertion is also observed on annealing.

Formation and Characterization of a BeOBeC Multiple Radical Featuring a Quartet Carbyne Moiety.

Through reaction of beryllium dimers with carbon monoxide, a carbonyl complex BeBeCO is formed in solid neon. Upon visible light excitation, the BeBeCO complex rearranges to a BeCOBe isomer, which further isomerizes to a low-energy BeOBeC species under UV-visible light excitation. These species are identified on the basis of infrared absorption spectroscopy with isotopic substitutions and quantum chemical studies.

Photoassisted Homocoupling of Methyl Iodide Mediated by Atomic Gold in Low-Temperature Neon Matrix.

Infrared spectroscopy and density functional theory calculations showed that the gold complexes [CH-Au-I] and [(CH)-Au-I], in which one and two CHI molecule(s), respectively, are oxidatively adsorbed on the Au atoms, are formed in a solid neon matrix via reactions between laser-ablated gold atoms and CHI. Global reaction route mapping calculations revealed that the heights of the activation barriers for the sequential oxidative additions to produce [CH-Au-I] and [(CH)-Au-I] are 0.53 and 1.

A Very Short Be-Be Distance but No Bond: Synthesis and Bonding Analysis of Ng-Be O -Ng' (Ng, Ng'=Ne, Ar, Kr, Xe).

Short interatomic distances below standard values for a single bond are usually identified with double or triple bonds. The synthesis and spectroscopic characterization of a molecule is reported where the distance between two beryllium atoms is shorter than a standard double bond but there is no bond. The cyclic diberyllium dioxide Be O molecule, which is coordinated by two noble gas atoms in Ng-Be O -Ng' (Ng, Ng'=Ne, Ar, Kr, Xe) was isolated and spectroscopically identified in low-temperature matrices.

The Oxygen-Rich Beryllium Oxides BeO4 and BeO6.

Two novel isomers of BeO4 with the structures OBeOOO and OBe(O3 ) in the electronic triplet state have been prepared as well as the known disuperoxide complex Be(O2 )2 in solid noble-gas matrices. We also report the synthesis of the oxygen-rich bis(ozonide) complex Be(O3 )2 in the triplet state which has a D2d equilibrium geometry. The molecular structures were identified by infrared absorption spectroscopy with isotopic substitutions as well as quantum chemical calculations.

Observation of Spontaneous C=C Bond Breaking in the Reaction between Atomic Boron and Ethylene in Solid Neon.

A ground-state boron atom inserts into the C=C bond of ethylene to spontaneously form the allene-like compound H2 CBCH2 on annealing in solid neon. This compound can further isomerize to the propyne-like HCBCH3 isomer under UV light excitation. The observation of this unique spontaneous C=C bond insertion reaction is consistent with theoretical predictions that the reaction is thermodynamically exothermic and kinetically facile.

Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides.

The chemistry of lanthanides (Ln=La-Lu) is dominated by the low-valent +3 or +2 oxidation state because of the chemical inertness of the valence 4f electrons. The highest known oxidation state of the whole lanthanide series is +4 for Ce, Pr, Nd, Tb, and Dy. We report the formation of the lanthanide oxide species PrO4 and PrO2 (+) complexes in the gas phase and in a solid noble-gas matrix.

Observation of Main-Group Tricarbonyls [B(CO)3 ] and [C(CO)3 ](+) Featuring a Tilted One-Electron Donor Carbonyl Ligand.

A combined experimental and theoretical study on the main-group tricarbonyls [B(CO)3 ] in solid noble-gas matrices and [C(CO)3 ](+) in the gas phase is presented. The molecules are identified by comparing the experimental and theoretical IR spectra and the vibrational shifts of nuclear isotopes. Quantum chemical ab initio studies suggest that the two isoelectronic species possess a tilted η(1) (μ1 -CO)-bonded carbonyl ligand, which serves as an unprecedented one-electron donor ligand.

Carbon Dioxide Activation by Scandium Atoms and Scandium Monoxide Molecules: Formation and Spectroscopic Characterization of ScCO3 and OCScCO3 in Solid Neon.

The reactions of carbon dioxide with scandium monoxide molecules and scandium atoms are investigated using matrix isolation infrared spectroscopy in solid neon. The species formed are identified by the effects of isotopic substitution on their infrared spectra as well as density functional calculations. The results show that the ground state ScO molecule reacts with carbon dioxide to form the carbonate complex ScCO3 spontaneously on annealing.

Infrared Photodissociation Spectroscopy of the Ni(O2)n(+) (n = 2-4) Cation Complexes.

The infrared spectra of mass-selected Ni(O2)n(+) (n = 2-4) and their argon-tagged complexes are measured by infrared photodissociation spectroscopy in the gas phase. The experimental spectra provide distinctive patterns allowing the determination of their geometric and electronic structures by comparison with the simulated vibrational spectra from density functional theory calculations. The [Ni(O2)2Ar2](+) cation complex was determined to have D2h symmetry involving a Ni(O2)2(+) core ion with two equivalent superoxide ligands side-on bound to a Ni(3+) cation center.

Formation and characterization of the boron dicarbonyl complex [B(CO)2](-).

We report the synthesis and spectroscopic characterization of the boron dicarbonyl complex [B(CO)2 ](-) . The bonding situation is analyzed and compared with the aluminum homologue [Al(CO)2 ](-) using state-of-the-art quantum chemical methods.

Carbon monoxide bonding with BeO and BeCO3 : surprisingly high CO stretching frequency of OCBeCO3.

The complexes OCBeCO3 and COBeCO3 have been isolated in a low-temperature neon matrix. The more stable isomer OCBeCO3 has a very high CO stretching mode of 2263 cm(-1) , which is blue-shifted by 122 cm(-1) with respect to free CO and 79 cm(-1) higher than in OCBeO. Bonding analysis of the complexes shows that OCBeO has a stronger OCBeY bond than OCBeCO3 because it encounters stronger π backdonation.

Experimental and theoretical studies of the infrared spectra and bonding properties of NgBeCO₃ and a comparison with NgBeO (Ng = He, Ne, Ar, Kr, Xe).

The novel neon complex NeBeCO3 has been prepared in a low-temperature neon matrix via codeposition of laser-evaporated beryllium atoms with O2 + CO/Ne. Doping by the heavier noble gas atoms argon, krypton and xenon yielded the associated adducts NgBeCO3 (Ng = Ar, Kr, Xe). The noble gas complexes have been identified via infrared spectroscopy.

Infrared spectra and structures of the neutral and charged CrCO2 and Cr(CO2)2 isomers in solid neon.

The reactions from codeposition of laser-ablated chromium atoms with carbon dioxide in excess neon are studied by infrared absorption spectroscopy. The species formed are identified by the effects of isotopic substitution on their infrared spectra. Density functional calculations are performed to support the spectral assignments and to interpret the geometric and electronic structures of the experimentally observed species.

Formation and infrared spectroscopic characterization of three oxygen-rich BiO4 isomers in solid argon.

The reactions of bismuth atoms and O2 have been investigated using matrix isolation infrared spectroscopy and density functional theory calculations. The ground state bismuth atoms react with dioxygen to form the BiOO and Bi(O2)2 complexes spontaneously on annealing. The BiOO molecule is characterized to be an end-on bonded superoxide complex, while the Bi(O2)2 molecule is characterized to be a superoxo bismuth peroxide complex, [Bi(3+)(O2(-))(O2(2-))].

Reactions of vanadium dioxide molecules with acetylene: infrared spectra of VO2(η(2)-C2H2)(x) (x = 1, 2) and OV(OH)CCH in solid neon.

Reactions of vanadium dioxide molecules with acetylene have been studied by matrix isolation infrared spectroscopy. Reaction intermediates and products are identified on the basis of isotopic substitutions as well as density functional frequency calculations. Ground state vanadium dioxide molecule reacts with acetylene in forming the side-on-bonded VO2(η(2)-C2H2) and VO2(η(2)-C2H2)2 complexes spontaneously on annealing in solid neon.

Formation and characterization of two interconvertible side-on and end-on bonded beryllium ozonide complexes.

The reactions of beryllium atoms with dioxygen were reinvestigated by matrix isolation infrared absorption spectroscopy. Besides the previously reported linear OBeO and cyclic Be(2)O(2) molecules, two interconvertible beryllium ozonide complexes were prepared and characterized. The BeOBe(η(2)-O(3)) complex was formed on annealing, which is characterized to be a side-on bonded ozonide complex with a planar C(2v) structure.

Matrix isolation spectroscopic and theoretical study of water adsorption and hydrolysis on molecular tantalum and niobium oxides.

The reactions of molecular tantalum and niobium monoxides and dioxides with water were investigated by matrix isolation infrared spectroscopy. In solid neon, the metal monoxide and dioxide molecules reacted with water to form the MO(H(2)O) and MO(2)(H(2)O) (M = Ta, Nb) complexes spontaneously on annealing. The MO(H(2)O) complexes photochemically rearranged to the more stable HMO(OH) isomers via one hydrogen atom transfer from water to the metal center under visible light excitation.

Tantalum dioxide complexes with dinitrogen. formation and characterization of the side-on and end-on bonded TaO2(NN)x (x = 1-3) complexes.

The reaction of tantalum dioxide molecule with dinitrogen has been studied by matrix isolation infrared spectroscopy. The tantalum dioxide molecules produced from laser evaporation of bulk Ta(2)O(5) target reacted with dinitrogen to form the TaO(2)(eta(1)-NN)(x) (x = 1-3) complexes on annealing, in which the N(2) ligands are end-on bonded to the tantalum metal center. The TaO(2)(eta(1)-NN)(3) complex decomposed to TaO(2)(eta(1)-NN)(2) under infrared irradiation.

Infrared spectra of the chloromethyl and bromomethyl cations in solid argon.

Infrared spectra of chloromethyl and bromomethyl cations isolated in solid argon are reported. Cocondensation of dichloromethane and dibromomethane with high-frequency discharged argon at 4 K produces the dichloromethane and dibromomethane cations, which dissociate upon visible light irradiation to form the chloromethyl and bromomethyl cations. On the basis of isotopic substitutions ((13)C and deuterium) as well as theoretical frequency calculations, photosensitive absorptions are assigned to different vibrational modes of the chloromethyl and bromomethyl cations.

Infrared spectrum of carbon trisulfide in solid argon.

Cocondensation of carbon disulfide with high-frequency discharged argon at 4 K produced carbon monosulfide and atomic sulfur, which reacted spontaneously upon annealing to form the carbon trisulfide molecule as identified from the multiplets observed in mixed (12)C, (13)C and (32)S, (34)S isotopic spectra. On the basis of isotopic substitution and theoretical frequency calculations, infrared absorptions at 1263.3 and 570.

Reaction of chloromethyl radical with dioxygen: formation of the chloromethylperoxy radical and its photodissociation in solid argon.

The reaction of chloromethyl radical with molecular oxygen in solid argon has been studied using matrix isolation infrared absorption spectroscopy. The chloromethyl radical was produced via codeposition of chloromethane with high frequency discharged argon atoms. The chloromethyl radical reacted with dioxygen spontaneously on annealing to form the chloromethylperoxy radical, which was characterized on the basis of isotopic splitting (Cl and O) as well as quantum chemical calculations.

Infrared spectrum of nitrobenzene anion in solid argon.

The infrared spectrum of the nitrobenzene anion isolated in solid argon is presented. The nitrobenzene anion was prepared by co-deposition of a nitrobenzene/Ar mixture with high-frequency discharged argon at 4 K. Photosensitive absorptions are assigned to different vibrational modes of the nitrobenzene anion on the basis of isotopic substitutions ((15)N and deuterium), as well as theoretical calculations.

Infrared spectra of the sulfenic ester CH3SOCH3 and its photodissociation products in solid argon.

UV light irradiation of dimethyl sulfoxide (DMSO) in low temperature solid argon matrix produces sulfenic ester, CH 3SOCH 3, a high energy structural isomer of DMSO. The sulfenic ester molecule further dissociates to the CH 2O-CH 3SH complex under 266 nm laser irradiation. The CH 2S-CH 3OH complex is also formed upon UV light irradiation.