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A new compound, 4-chlorobenzylammonium nitrate, was obtained by a reaction between 4-chlorobenzylamine and nitric acid, and characterized by X-ray diffraction and FT-IR spectroscopy. The phenyl ring and the nitro group were essentially coplanar in the obtained crystal. The aminomethyl substituent CH2 NH3+ lies out the plane of the aromatic ring as evidenced by the torsion angle Nl C7 C1 C6 of 88.2°. The crystal packing was formed by an infinite bi-dimensional layers with graph-set motif R48(16), and stabilized by N H⋯O hydrogen bond-type intermolecular interactions. In addition, molecular geometry in the electronic ground state, Hirshfeld surface, vibrational wavenumbers, molecular electronic plane (MEP), and Natural bond orbital (NBO) analysis were performed using the density functional theory (DFT/B3LYP) with 6-31+G* basis set. Theoretical and experimental results are in good agreement. The NBO analysis confirms that the N H⋯O intermolecular interactions notably affect crystal packing in this molecule.

To accurately characterize the large amplitude motions and soft degrees of freedom of isolated molecules, sampling their conformational landscape by molecular mechanics and quantum chemical calculations may provide a valuable insight into the structure and dynamics. However, the resulting models need to be validated by a reliable experimental counterpart. For ethyl pentanoates, which belong to the family of fruit esters, benchmark calculations at different levels of theory showed that the C-C bond in proximity to the ester carbonyl group exhibits a large amplitude motion that is extremely sensitive to the choice of quantum chemical method and basis set. In such cases, insights from high-resolution molecular jet techniques are ideal to accurately identify and characterize soft degrees of freedom. Here, we report on the most abundant conformer of ethyl 2-ethyl butyrate using Fourier-transform microwave spectroscopy. We show that - unlike other structurally related pentanoates for which gas-phase and crystallographic data is available - ethyl 2-ethyl butyrate possesses a Cs symmetry plane under molecular jet conditions.

A novel bismuthates(III) complex, (C6H14N)4[BiCl6]Cl·2H2O, was synthesized and characterized by X-ray diffraction and FT-IR spectroscopy. Its structure consists of protonated cyclohexylamine cations, discrete [BiCl6]3− anions, chlorine anions and water molecules. The chlorobismuthate(III) anions alternate with the water molecules O1 as to form hydrogen-bonded helical chain running along the crystallographic b-axis with a period of 17.622 A. These components are connected into a three-dimensional network via hydrogen bonds. In addition, the ground state geometry, vibrational wavenumbers and Natural bond orbital (NBO) analysis were studied by means of density functional theory (DFT/B3LYP) with LanL2DZ basis set. Theoretical results are within the range of the experimental data. The NBO analysis reveals the influence of the N–H…O, N–H…Cl and O H…Cl intermolecular interactions on crystal packing. Moreover, the electrochemical behavior of this complex was investigated in DMSO by cyclic voltammetry (CV).

A systematic study on the magnetic property variations of Pd13 particles as a function of particle sizes and structures, and of Pd13 interactions with the (100) TiO2 anatase surface, was carried out with standard density functional theory (DFT) based method with periodic boundary conditions. The biplanar Pd13 structure with the spin state quintet is obtained to be the ground state in the gas-phase and on the anatase surface, being more stable than the compact icosahedral configuration by 0.067 and 0.865 eV, respectively. The preferred particle nucleation on the anatase surface is that with the largest possible contacts between Pd13 and the oxide surface oxygens. The supported Pd13 particles are better stabilized by 0.3 eV compared to the isolated ones. The profiles of the relative energies as a function of the spin state reveal that the Pd13 magnetic isomers, belonging to the same cluster topology, become closer in energy and nearly degenerate on the anatase surface compared to their gas-phase counterpart...

In two recent reports of the same series (J. Phys. Chem. B 2007, 111, 1470-1477 and J. Phys. Chem. B 2009, 113, 3169-3178), we have described the geometrical and vibrational analysis of glycine and amino acids (AAs) with hydrophobic side chains through the joint use of optical spectroscopy and quantum mechanical calculations. Here, we report Raman scattering and Fourier-Transform Infrared (FT-IR) Attenuated Total Reflectance (ATR) spectra measured from the aqueous solutions (H(2)O and D(2)O) of L-lysine and L-arginine, i.e. two alpha-AAs with positively charged hydrophilic side chains. The discussion on the vibrational features of both AAs could be carried out thanks to the theoretical calculations performed by means of the Density Functional Theory (DFT) approach at the B3LYP/6-31++G* level. We have analyzed the influence of implicit (with a polarizable dielectric continuum) and explicit (by means of an H(2)O cluster interacting with H-donor and H-acceptor sites of AAs) hydration models. In addition, through the calculated geometrical parameters and vibrational wavenumbers, a discussion was performed on the effect of the Cl(-) anion interacting with the positively charged side chains of explicitly hydrated AAs.

1 - Article; Raman scattering and Fourier-transform infrared (FT-IR) attenuated transmission reflectance (ATR) spectra of two alpha-amino acids (alpha-AAs), i.e., glycine and leucine, were measured in H2O and D2O (at neutral pH and pD). This series of observed vibrational data gave us the opportunity to analyze vibrational features of both AAs in hydrated media by density functional theory (DFT) calculations at the B3LYP/6-31++G* level. Harmonic vibrational modes calculated after geometry optimization on the clusters containing each AA and 12 surrounding water molecules, which represent primary models for hydration scheme of amino acids, allowed us to assign the main observed peaks.