The HKrCCHCO complex: an ab initio and matrix-isolation study.

We report an experimental and theoretical study on new noble-gas hydride complex HKrCCHCO2, which is the first known complex of a krypton hydride with carbon dioxide. This species was prepared by the annealing-induced H + Kr + CCHCO2 reaction in a krypton matrix, the CCHCO2 complexes being produced by UV photolysis of propiolic acid (HCCCOOH). The H-Kr stretching mode of the HKrCCHCO2 complex at 1316 cm-1 is blue-shifted by 74 cm-1 from the most intense H-Kr stretching band of HKrCCH monomer.

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process.

The lanthanides (Ln) are an essential part of many advanced technologies. Our societal transformation toward renewable energy drives their ever-growing demand. The similar chemical properties of the Ln pose fundamental difficulties in separating them from each other, yet high purity elements are crucial for specific applications.

Low-Temperature Wafer-Scale Deposition of Continuous 2D SnS Films.

Semiconducting 2D materials, such as SnS , hold immense potential for many applications ranging from electronics to catalysis. However, deposition of few-layer SnS films has remained a great challenge. Herein, continuous wafer-scale 2D SnS films with accurately controlled thickness (2 to 10 monolayers) are realized by combining a new atomic layer deposition process with low-temperature (250 °C) postdeposition annealing.

Formic acid dimers in a nitrogen matrix.

Formic acid (HCOOH) dimers are studied by infrared spectroscopy in a nitrogen matrix and by ab initio calculations. We benefit from the use of a nitrogen matrix where the lifetime of the higher-energy (cis) conformer is very long (∼11 h vs. 7 min in an argon matrix).

Photochemistry of the HO/CO System Revisited: The HXeOH···CO Complex in a Xenon Matrix.

We report on the complex of a noble-gas hydride HXeOH with carbon monoxide. This species is prepared via the annealing-induced H + Xe + OH···CO reaction in a xenon matrix, the OH···CO complexes being produced by VUV photolysis of the HO···CO complexes. The H-Xe stretching mode of the HXeOH···CO complex absorbs at 1590.

Spectroscopic characterization of the complex of vinyl radical and carbon dioxide: Matrix isolation and ab initio study.

We report on the preparation and vibrational characterization of the CH⋯CO complex, the first example of a stable intermolecular complex involving vinyl radicals. This complex was prepared in Ar and Kr matrices using UV photolysis of propiolic acid (HCOOH) and subsequent thermal mobilization of H atoms. This preparation procedure provides vinyl radicals formed exclusively as a complex with CO, without the presence of either CO or CH monomers.

Complex between Formic Acid and Nitrous Oxide: A Matrix-Isolation and Computational Study.

The complex of formic acid (FA, HCOOH) with nitrous oxide (NO) was studied experimentally and computationally. Eight structures of the trans-FA···NO complex and nine structures of the cis-FA···NO complex were found at the density functional theory (M06-2X and wB97XD), MP2(full), and CCSD(T)-F12a levels. Two structures of the trans-FA···NO complex (1t and 3t) and two structures of the cis-FA···NO complex (1c and 3c) were identified by infrared spectroscopy in an argon matrix.

Conformational Switching of HOCO Radical: Selective Vibrational Excitation and Hydrogen-Atom Tunneling.

Conformers of carboxyl radical (HOCO) have been studied by IR spectroscopy in argon and nitrogen matrices. In an argon matrix, only the lower-energy conformer trans-HOCO is observed, whereas both cis and trans conformers are found for deuterated carboxyl radical DOCO. In a nitrogen matrix, both conformers of HOCO and DOCO isotopologues can be prepared, indicating strong stabilization of the higher-energy cis conformer by a nitrogen matrix.

An aromatic noble-gas hydride: CHCCXeH.

We report on the aromatic noble-gas hydride, CHCCXeH, identified in a xenon matrix using infrared spectroscopy and extensive quantum chemical calculations. This molecule is prepared by 250-nm photolysis of phenylacetylene (CHCCH) isolated in a xenon matrix and subsequent thermal mobilization of hydrogen atoms at about 40 K. The characteristic H-Xe stretching mode of CHCCXeH is observed at about 1500 cm, and a number of other fundamentals also appear in the experimental spectra.

Effect of Noncovalent Interactions on Vibronic Transitions: An Experimental and Theoretical Study of the C H⋅⋅⋅CO Complex.

We report on the experimental and theoretical infrared spectrum of the C H⋅⋅⋅CO complex. This complex was prepared by UV photolysis of propiolic acid (HC OOH) in argon and krypton matrices. The experimental bands of C H in the C H⋅⋅⋅CO complex are blue-shifted from those of the C H monomer.

VUV photochemistry of the HOCO complex in noble-gas matrices: formation of the OHCO complex and the HOCO radical.

Vacuum ultraviolet (VUV, 130-170 nm) photochemistry of the HOCO complex is studied by matrix-isolation infrared spectroscopy. The HOCO complexes in Ne, Ar, Kr, and Xe matrices are generated by ultraviolet (UV, 193 and 250 nm) photolysis of formic acid (HCOOH). VUV photolysis of the HOCO complexes is found to lead to the formation of the OHCO radical-molecule complexes and trans-HOCO radicals.

Matrix-isolation and computational study of H2CCCl and H2CCBr radicals.

We report on two new radicals, H2CCCl and H2CCBr, prepared in low-temperature noble-gas matrices and characterized using infrared spectroscopy. These radicals are made by UV photolysis of HCCCl and HCCBr and subsequent thermal annealing to mobilize hydrogen atoms in the matrices and promote their reaction with the residual precursor molecules. Three characteristic infrared bands are observed for each radical.

Photoisomerization of azobenzenes isolated in cryogenic matrices.

2,2'-Dihydroxyazobenzene (DAB), 2,2'-azotoluene (AT) and azobenzene (AB) were isolated in argon and xenon matrices and their molecular structures and photochemical transformations were characterized by infrared spectroscopy and theoretical calculations. All these compounds can adopt the E and Z isomeric forms around the central CNNC moiety, which can be enriched by several conformational and tautomeric modifications for DAB and AT. A number of DAB and AT isomeric forms were identified for the first time.

Surface-Enhanced Raman Scattering of Silicon Nanocrystals in a Silica Film.

Surface-enhanced Raman scattering (SERS) is an intriguing effect, efficiency of which depends on many factors and whose applicability to a given system is not obvious before the experiment. The motivation of the present work is to demonstrate the SERS effect on silicon nanocrystals (Si-nc) embedded in silica, the material of high technological importance. Using the Ag overlayer method, we have found the SERS effect for this material.

Infrared Spectrum of Toluene: Comparison of Anharmonic Isolated-Molecule Calculations and Experiments in Liquid Phase and in a Ne Matrix.

First-principles anharmonic calculations are carried out for the CH stretching vibrations of isolated toluene and compared with the experimental infrared spectra of isotopologues of toluene in a Ne matrix at 3 K and of liquid toluene at room temperature. The calculations use the vibrational self-consistent field method and the B3LYP potential surface. In general, good agreement is found between the calculations and experiments.

Acetic acid-water complex: The first observation of structures containing the higher-energy acetic acid conformer.

Non-covalent interaction of acetic acid (AA) and water is studied experimentally by IR spectroscopy in a nitrogen matrix and theoretically at the MP2 and coupled-cluster with single and double and perturbative triple excitations [CCSD(T)]/6-311++G(2d,2p) levels of theory. This work is focused on the first preparation and characterization of complexes of higher-energy (cis) conformer of AA with water. The calculations show three 1:1 structures for the trans-AA⋯H2O complexes and three 1:1 structures for the cis-AA⋯H2O complexes.

Matrix-isolation and ab initio study of HKrCCCl and HXeCCCl.

We report on two new noble-gas molecules, HKrCCCl and HXeCCCl, prepared in low-temperature Kr and Xe matrices. These molecules are made by UV photolysis of HCCCl in the matrices and subsequent thermal annealing. The HCCCl precursor is produced by microwave discharge of a mixture of a matrix gas with trichloroethylene (HClC=CCl2).

X-ray induced dimerization of cinnamic acid: Time-resolved inelastic X-ray scattering study.

A classic example of solid-state topochemical reactions is the ultraviolet-light induced photodimerization of α-trans-cinnamic acid (CA). Here, we report the first observation of an X-ray-induced dimerization of CA and monitor it in situ using nonresonant inelastic X-ray scattering spectroscopy (NRIXS). The time-evolution of the carbon core-electron excitation spectra shows the effects of two X-ray induced reactions: dimerization on a short time-scale and disintegration on a long time-scale.

Acetic acid dimers in a nitrogen matrix: Observation of structures containing the higher-energy conformer.

Acetic acid (AA) dimers are studied experimentally by infrared spectroscopy in a N2 matrix and theoretically at the MP2/6-311++G(2d,2p) level of approximation. This work is focused on the first preparation and characterization of structures containing the higher-energy (cis) conformer of AA. Nine trans-trans, fourteen trans-cis, and six cis-cis dimers are theoretically predicted.

Multimodal non-linear optical imaging for the investigation of drug nano-/microcrystal-cell interactions.

Drug nano-/microcrystals are being used for sustained parenteral drug release, but safety and efficacy concerns persist as the knowledge of the in vivo fate of long-living particulates is limited. There is a need for techniques enabling the visualization of drug nano-/microcrystals in biological matrices. The aim of this work was to explore the potential of coherent anti-Stokes Raman scattering (CARS) microscopy, supported by other non-linear optical methods, as an emerging tool for the investigation of cellular and tissue interactions of unlabeled and non-fluorescent nano-/microcrystals.

Fluorinated noble-gas cyanides FKrCN, FXeCN, and FXeNC.

We report on three new noble-gas molecules, FKrCN, FXeCN, and FXeNC, prepared in low-temperature Kr and Xe matrices. These molecules are made by UV photolysis of FCN in the matrices and subsequent thermal annealing. The FCN precursor is produced by deposition of the matrix gas containing (FCN)3 through a microwave discharge.

Optical and Structural Properties of Si Nanocrystals in SiO2 Films.

Optical and structural properties of Si nanocrystals (Si-nc) in silica films are described. For the SiOx (x < 2) films annealed above 1000 °C, the Raman signal of Si-nc and the absorption coefficient are proportional to the amount of elemental Si detected by X-ray photoelectron spectroscopy. A good agreement is found between the measured refractive index and the value estimated by using the effective-medium approximation.

Experimental and theoretical study of the HXeI⋯HCl and HXeI⋯HCCH complexes.

The HXeI⋯HCl and HXeI⋯HCCH complexes are studied computationally and experimentally in a Xe matrix. In the experiments, three bands of the HXeI⋯HCl complex and one band of the HXeI⋯HCCH complex in the H-Xe stretching region are observed. The monomer-to-complex shifts are +94, +111, and +155 cm(-1) for the HXeI⋯HCl complex and +49 cm(-1) for the HXeI⋯HCCH complex.