Matrix Isolation of the Arsinoborene FB-As═BF with an As═B Double Bond Character.

We report on the generation of FB-As═BF, an arsinoborene (boranylidenearsane) with a genuine As═B double bond, where both the As and B atoms are two-coordinate. It was obtained from the reaction of AsF with laser-ablated boron atoms under cryogenic conditions in neon and argon matrices. In addition, the single-bonded arsenic-boron radicals FB-AsF and FB-AsF were characterized.

The Trifluorooxygenate Anion [OF]: Spectroscopic Evidence for a Binary, Hypervalent Oxygen Species.

Experimental evidence for hypervalent compounds of second-row elements is still scarce in literature. Here, we present the first report of the long-sought binary, hypervalent trifluorooxygenate anion [OF]. It was isolated in solid Ne matrices under cryogenic conditions after reacting oxygen difluoride with free fluoride ions from laser ablation of alkali metal fluorides MF (M=Li-Cs).

B[double bond, length as m-dash]P double bonds relieved from steric encumbrance: matrix-isolation infrared spectroscopy of the phosphaborene FB-P[double bond, length as m-dash]BF and the triradical B[double bond, length as m-dash]PF.

Free phosphaborenes have a labile boron-phosphorus double bond and therefore require extensive steric shielding by bulky substituents to prevent isomerisation and oligomerisation. In the present work, the small free phosphaborene FB-P[double bond, length as m-dash]BF was isolated by matrix-isolation techniques and was characterised by infrared spectroscopy in conjunction with quantum-chemical methods. In contrast to its sterically hindered relatives, this small phosphaborene exhibits an acute BPB angle of 83° at the CCSD(T) level.

Investigation of Isolated IrF , IrF Anions and M[IrF] (M=Na, K, Rb, Cs) Ion Pairs by Matrix-Isolation Spectroscopy and Relativistic Quantum-Chemical Calculations.

The molecular IrF , IrF anions and M[IrF] (M=Na, K, Rb, Cs) ion pairs were prepared by co-deposition of laser-ablated alkali metal fluorides MF with IrF and isolated in solid neon or argon matrices under cryogenic conditions. The free anions were obtained as well by co-deposition of IrF with laser-ablated metals (Ir or Pt) as electron sources. The products were characterized in a combined analysis of matrix IR spectroscopy and electronic structure calculations using two-component quasi-relativistic DFT methods accounting for spin-orbit coupling (SOC) effects as well as multi-reference configuration-interaction (MRCI) approaches with SOC.

Photoinduced Dual C-F Bond Activation of Hexafluorobenzene Mediated by Boron Atom.

The reaction of laser-ablated boron atoms with hexafluorobenzene (C F ) was investigated in neon and argon matrices, and the products are identified by matrix isolation infrared spectroscopy and quantum-chemical calculations. The reaction is triggered by a boron atom insertion into one C-F bond of hexafluorobenzene on annealing, forming a fluoropentafluorophenyl boryl radical (A). UV-Vis light irradiation of fluoropentafluorophenyl boryl radical causes generation of a 2-difluoroboryl-tetrafluorophenyl radical (B) via a second C-F bond activation.

Exposing the Oxygen-Centered Radical Character of the Tetraoxido Ruthenium(VIII) Cation [RuO ].

The tetraoxido ruthenium(VIII) radical cation, [RuO ] , should be a strong oxidizing agent, but has been difficult to produce and investigate so far. In our X-ray absorption spectroscopy study, in combination with quantum-chemical calculations, we show that [RuO ] , produced via oxidation of ruthenium cations by ozone in the gas phase, forms the oxygen-centered radical ground state. The oxygen-centered radical character of [RuO ] is identified by the chemical shift at the ruthenium M edge, indicative of ruthenium(VIII), and by the presence of a characteristic low-energy transition at the oxygen K edge, involving an oxygen-centered singly-occupied molecular orbital, which is suppressed when the oxygen-centered radical is quenched by hydrogenation of [RuO ] to the closed-shell [RuO H] ion.

Infrared spectroscopic and theoretical investigations of novel iridium oxyfluorides.

The iridium oxyfluorides (OIrF, OIrF and FOIrF) were prepared for the first time by the reaction of IR-laser ablated iridium atoms and OF, isolated in solid neon and argon matrices. The assignments of the main vibrational absorptions of these products were supported by a combined analysis of IR-matrix-isolation spectroscopy with OF substitution and quantum-chemical calculations. The OIrF molecule exhibits triple bond character.

Infrared Spectroscopic and Theoretical Investigations of Group 13 Oxyfluorides OMF and OMF (M=B, Al, Ga, In).

Group 13 oxyfluorides OMF were produced by the reactions of laser-ablated group 13 atoms M (M=B, Al, Ga and In) with OF and isolated in excess neon or argon matrices at 5 K. These molecules were characterized by matrix-isolation infrared spectroscopy and isotopic substitution experiments in conjunction with quantum-chemical calculations. The calculations indicate that the OMF molecules have a B ground state with C symmetry.

Sniffing out camphor: the fine balance between hydrogen bonding and London dispersion in the chirality recognition with α-fenchol.

Binary complexes between the chiral monoterpenoids camphor and α-fenchol were explored with vibrational and rotational jet spectroscopy as well as density functional theory in order to explore how chirality can influence the binding preferences in gas-phase complexes. The global minimum structures of the two diastereomers were assigned. It is found that chirality recognition leads to different compromises in the fine balance between intermolecular interactions.

Hydrogen Delocalization in an Asymmetric Biomolecule: The Curious Case of Alpha-Fenchol.

Rotational microwave jet spectroscopy studies of the monoterpenol α-fenchol have so far failed to identify its second most stable torsional conformer, despite computational predictions that it is only very slightly higher in energy than the global minimum. Vibrational FTIR and Raman jet spectroscopy investigations reveal unusually complex OH and OD stretching spectra compared to other alcohols. Via modeling of the torsional states, observed spectral splittings are explained by delocalization of the hydroxy hydrogen atom through quantum tunneling between the two non-equivalent but accidentally near-degenerate conformers separated by a low and narrow barrier.

Rovibronic signatures of molecular aggregation in the gas phase: subtle homochirality trends in the dimer, trimer and tetramer of benzyl alcohol.

Molecular aggregation is of paramount importance in many chemical processes, including those in living beings. Thus, characterization of the intermolecular interactions is an important step in its understanding. We describe here the aggregation of benzyl alcohol at the molecular level, a process governed by a delicate equilibrium between OH⋯O and OH⋯π hydrogen bonds and dispersive interactions.

Simple models for the quick estimation of ground state hydrogen tunneling splittings in alcohols and other compounds.

Models for the quick estimation of energy splittings caused by coherent tunneling of hydrogen atoms are evaluated with available experimental data for alcohols and improvements are proposed. The discussed models are mathematically simple and require only results from routine quantum chemical computations, i.e.

Predicting OH stretching fundamental wavenumbers of alcohols for conformational assignment: different correction patterns for density functional and wave-function-based methods.

A model is presented for the prediction of OH stretching fundamental wavenumbers of alcohol conformers in the gas phase by application of a small set of empirical anharmonicity corrections to calculations in the harmonic approximation. In contrast to the popular application of a uniform scaling factor, the local chemical structure of the alcohol is taken into account to greatly improve accuracy. Interestingly, different correction patterns emerge for results of hybrid density functional (B3LYP-D3 and PBE0-D3) and wave-function-based methods (SCS-LMP2, LCCSD(T*)-F12a and CCSD(T)-F12a 1D).

Understanding benzyl alcohol aggregation by chiral modification: the pairing step.

A combination of linear infrared and Raman spectroscopy in supersonic slit jet expansions is used to clarify the conformational preferences in the dimer of the transiently chiral benzyl alcohol (phenylmethanol) under vacuum isolation. By experimentally exploring close analogies with the permanently chiral 1-phenylethanol, which is conformationally locked in the jet through intramolecular chirality induction, and by computational analysis of their conformational energy landscapes, several conclusions are drawn. The lowest energy dimer is confirmed to be cooperatively OHOHπ-bonded and shown to be homochiral.

The reduced cohesion of homoconfigurational 1,2-diols.

By a combination of linear FTIR and Raman jet spectroscopy, racemic trans-1,2-cyclohexanediol is shown to form an energetically unrivalled S4-symmetric heterochiral dimer in close analogy to 1,2-ethanediol. Analogous experiments with enantiopure trans-1,2-cyclohexanediol reveal the spectral signature of at least three unsymmetric homochiral dimers. A comparison to signal-enhanced spectra of 1,2-ethanediol and to calculations uncovers at least three transiently homochiral dimer contributions as well.

Vibrational Signatures of Chirality Recognition Between α-Pinene and Alcohols for Theory Benchmarking.

Chirality recognition between largely rigid molecules can be applied as a benchmark for the description of intermolecular forces by theoretical methods, because one constituent is merely mirrored, so other deficits of the methods such as neglect of anharmonicity should mostly cancel. To test this approach, mixed OH⋅⋅⋅π-bridged dimers between the enantiomers of the bicyclic monoterpene α-pinene and the chiral secondary alcohols borneol, α-fenchol, isopinocampheol, and 1-phenylethanol were formed in a supersonic jet and probed by linear FTIR spectroscopy. With borneol and α-fenchol, pronounced shifts in the hydroxyl stretching frequencies upon exchange of the handedness are observed.

Molecular docking via olefinic OH···π interactions: a bulky alkene model system and its cooperativity.

Complexes of t-butyl alcohol with norbornene and its monocyclic constituents cyclopentene and cyclohexene are studied via their OH stretching fundamental transitions in supersonic jet expansions. Compared to OH···OH hydrogen bonds, the spectral shifts due to OH···π bonding in the mixed dimers are reduced by a factor of 2. Mixed trimers show substantially different spectral signatures due to cooperative effects.

An effective community-based mentoring program for return to work and school after brain and spinal cord injury.

Information is presented on a community-based mentoring program, developed to work with existing community agencies and provide structure to the frequently confusing network of services for young adults, ages 16 to 26 years, with a recently acquired disability including TBI, SCI, and other neurological disorders. The over-arching goal of the Mentoring Program was to improve the ability of individuals with disabilities to access and maximally utilize the services and programs that are available in the community. The two objectives of this study were: (1) to demonstrate continuing increases in standardized measures of community integration from the time of enrollment in the program to the time of exit from the program, and (2) to improve the percentage of youth and young adults with disabilities who successfully access post-secondary education or employment opportunities.