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Molecular silicon trioxide has been isolated in argon matrices at low temperature (i) as a secondary reaction product within Si+2(O2) aggregates or (ii) as a primary product in the direct reaction of silicon monoxide with oxygen molecules after UV excitation at 5.17 eV. The silicon trioxide molecule has been characterized through the observation of five fundamental vibrations for at least eight different isotopic species, namely 28Si16O3, 29Si16O3, 30Si16O3, 16OSi18O2, 18OSi16O18O, 16OSi16O18O, 18OSi16O2, and Si18O3. From the experimental data, a structure of the C2v symmetry can be deduced with a Si=O double bond much shorter than two equivalent Si–O single bonds. These findings are fully supported by DFT calculations, which moreover predict a large binding energy of about 60 kcal/mol with respect to the separate fragments (SiO and O2). The possible reaction pathways are also discussed. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The reaction of atomic titanium with nitrous oxide hasbeen reinvestigatedusing matrix isolation in solid neon coupled to infrared spectroscopyand by quantum chemical methods. Our technique of sublimation of Tiatoms from a filament heated at about 1500 °C allowed the formationof three species: one Ti–N2O pair of van der Waals(vdW) type characterized by small red shift with respect to N2O monomer, and two isomers of OTi–N2pairwhere N2is in interaction with the OTi moiety either withend-on or side-on structure. Interconversion between these structureshas been performed with several wavelengths. In the visible and near-ultravioletthe conversion vdW → OTi-N2(end-on) is observedwith characteristic times strongly varying according to the wavelength.In the near-infrared the conversion OTi–N2(end-on)→ OTi–N2(side-on) occurs, the vdW speciesremaining unchanged. These selectivities allow 8, 6, and 4 vibrationaltransitions to be assigned for vdW, 3[OTi(η1-NN)] (end-on), and 1[OTi(η2-NN)] (side-on),respectively. Electronic and geometrical structures are also investigatedwith double-hybrid functionals. It has been shown that the side-ongeometry corresponds to the ground state of 1[OTi(η2-NN)] in the singlet electronic state. The theoretical vibrationalanalysis supports well the experimental attributions. [ABSTRACT FROM AUTHOR]

Transamination of [Co{N(SiMe 3 ) 2 } 2 ] 2 with C 6 H 4 (NHSiiPr 3 ) 2 gave the centrosymmetric trinuclear [{Co ter N(SiMe 3 ) 2 (μ-η-[o-C 6 H 4 (κNSiiPr 3 ) 2 ])} 2 Co int ] (1) (Co ter , Co int =terminal, internal Co, respectively), with 3-coordinate Co ter , and Co int "sandwiched" between the o-phenylenes of the two ligands; experimental and computational data support Co II centres and ditopic o-amido-imino-cyclohexen-allyl ligands; magnetic studies reveal intermetallic ferromagnetic interactions and single-molecule magnet (SMM) character. One-electron reduction of 1 yielded the salt [K(18-crown-6)(THF) 2 ][{Co ter N(SiMe 3 ) 2 (μ-η-[o-C 6 H 4 (κNSiiPr 3 ) 2 ])} 2 Co int ] (4) with the anion isostructural to 1. The centrosymmetric Fe complex [{Fe ter N(SiMe 3 ) 2 (μ-η-[o-C 6 H 4 (κNSiiPr 3 ) 2 ])} 2 Fe int ] (5), analogous to 1, was also obtained., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The infrared spectra of CH3Cl + H2O isolated in solid neon at low temperature have been investigated. High concentration studies of water (0.01%-4%) and subsequent annealing lead to the formation of the ternary CH3Cl:(H2O)2 complex. Detailed vibrational assignments were made on the observed spectra of water and deuterated water engaged in the complex. In parallel, structural, energetic, and vibrational properties of the complex have been studied at the second-order Møller-Plesset perturbation theory using several basis sets. Anaharmonic correction to the vibrational frequencies has been done with the standard second-order perturbation approach. It was shown that the ground state of the complex has a cyclic form for which the nonadditive three-body contribution was found to be around 10% of the interaction energy.

The IR spectra of H2O+NO, HDO+NO, and D2O+NO, isolated in solid neon at low temperature have been investigated. Concentration effects and detailed vibrational analysis of deuterated and partially deuterated species allowed identification of three 1:1 HDO-NO species, two 1:1 D2O-NO species, and only one 1:1 H2O-NO complex. From comparison between the experimental spectra and the results of DFT calculations, it appeared that two different types of weakly bound complexes between water and nitric oxide can be formed in a neon matrix. The first species is a 1:1 complex where bonding occurs between water hydrogen and nitric oxide nitrogen, in which OH-N and OD-N intermolecular bonds are engaged. For this complex only DOD-NO, HOD-NO, and DOH-NO isotopic species have been experimentally detected and no IR bands of HOH-NO were observed. This result could be explained by the fact that the dissociation energy of HOH-NO is lower than those of DOD-NO, HOD-NO and DOH-NO. For the second detected 1:1 H2O-NO complex and its isotopic variants, the H2O-NO potential surface was explored systematically at the B3LYP level, but no stable species corresponding to the complex could be calculated. The structure of the second observed 1:1 H2O-NO complex results from columbic attractions between water and nitric oxide and could be stabilized only in matrix, probably by interaction between NO, water and (Ne)n.