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This paper provides experimental and theoretical study of reaction of [2 + 2] cycloaddition of substituted α–unsaturated isophorone dyes, involving high resolution electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI) tandem mass spectrometric (MS/MS) analysis in solution and in gas–phase (GP) of substituted 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone and configurationally locked polyenes (CLP). The ab initio and density functional theoretical (DFT) examining provides information about molecular geometry, thermodynamics, kinetics and ionization potentials of sixty six isomers of dimeric dyes, including corresponding cis -anti- cis and cis -syn- cis head-to-tail and head-to-head forms. The comparative collision induced dissociation (CID) or collision activated MS and theoretical analyses carried out bring light into the mechanisms of competitive dimerization within the frame of 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone; molecular and environmental factors governing regioselectivity of reaction. The analyses involve both qualitative and quantitative kinetics and thermodynamics of experimental MS data along with corresponding theoretical examining of CLP dimers. As far as 3-[2-(X-substituted-phenyl)-vinyl]-5,5-dimethyl-cyclohex-2-enone and CLP dyes have already found an industrial scale application as non-linear optical materials (NLO) for THz wave generation and detection as well as pharmaceutics for treatment of and preventing of neurodegenerative diseases, this study has a strong transdisciplinary impact to many research fields as well as to still not well understood, but crucial to fields of organic synthesis and catalysis, molecular level fundamentals of chemical reactivity in gas– and condense phases. Following the latter lines of contributions of the work, we might hopefully expect that the prospective highlighted in this study should inspired further research effort devoted to correlative quantitative thermodynamic and kinetic CID mass spectrometric and quantum chemical analyses, which allow to improve the reaction effectiveness depending on the complexity of the wanted CLP scaffolds. [ABSTRACT FROM AUTHOR]

Abstract: The paper studied factors of the gas phase (GP) ionic stabilization of molecular organic crystals of salts. The single crystal X-ray diffraction, electrospray ionization (ESI) and matrix-assisted laser desorption/ionization (MALDI) mass spectrometric (MS) methods are employed. The GP phenomena are explained by the comprehensive quantum-chemical theoretical models, providing significant information for the electronic structures and thermodynamics of the observed MS species. The n-chloro-alkyl aliphatic heterocyclic 5-sulfosalicylates i.e. 1-(2-chloroethyl) pyrrolidinium 5-sulfosalicylicilate (1), 1-(2-chloroethyl)-piperidinium 5-sulfosalicylicilate (2), and 1-(3-chloropropyl) piperidinium 5-sulfosalicylicilate (3) are examined. The ionic systems that contain N+H-heterocyclic fragments, a complex MS image variety of monocations, quaternary ammonium dications and hydrogen bonded molecular complexes revealed. Their stabilization is explained by proton transfer (PT), charge-transfer (CT) and Jahn–Teller (JT) effects. The 4-(2-chloroethyl) morpholinium hydrochloride crystals (4) yielded quaternary ammonium adduct which structure is crystallographically determined. In parallel the GP stabilized ions of 4 are analyzed. The complementary application of the single-crystal X-ray diffraction and MS methods provided unique structural evidences in condenses and in the GP able to understand the competitive intramolecular and environmental factors contributing to the thermodynamics stability of the ionic species. Therefore, the data reported are helped for more comprehensive knowledge of the basic mass spectrometric GP and phase transition phenomena with both its methodological development and used robust analytical technique application. [Copyright &y& Elsevier]

Abstract: A comprehensive screening of fifteen functionalized Ergot-alkaloids, containing bulk aliphatic cyclic substituents at D-ring of the ergoline molecular skeleton was performed, studying their structure-active relationships and model interactions with α 2A -adreno-, serotonin (5HT2A ) and dopamine D3 (D3A) receptors. The accounted high affinity to the receptors binding loops and unusual bonding situations, joined with the molecular flexibility of the substituents and the presence of proton accepting/donating functional groups in the studied alkaloids, may contribute to further understanding the mechanisms of biological activity in vivo and in predicting their therapeutic potential in central nervous system (CNS), including those related the Schizophrenia. Since the presented correlation between the molecular structure and properties, was based on the comprehensively theoretical computational and experimental physical study on the successfully isolated derivatives, through using routine synthetic pathways in a relatively high yields, marked these derivatives as ‘treasure’ for further experimental and theoretical studied in areas such as: (a) pharmacological and clinical testing; (b) molecular-drugs design of novel psychoactive substances; (c) development of the analytical protocols for determination of Ergot-alkaloids through a functionalization of the ergoline-skeleton, and more. [Copyright &y& Elsevier]

Abstract: The paper presented with qualitative and quantitative analysis of alkaloids in solid-state, using the excitations within the THz-spectroscopic region of 300–30cm−1 (9.00–0.9THz). Series of nine plant flavonoids (FLs) and their mixtures were analyzed both qualitatively and quantitatively. For first time in the literature was reported the quantitative analysis of alkaloids and their mixtures within the THz-region using the solid-state Raman spectroscopy, and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS). The calibration and validation, concentration limit of detection (LOD), limit of quantification (LOQ), and linearity limit (LL) were obtained. The chemometric nonlinear and linear approaches for analysis and interpretation of the quantities were applied. The results obtained were compared with a parallel QA, using the calibrated and validated HPLC electrospray ionization (ESI) mass spectrometric method, electronic absorption (EAs) and CD spectroscopy. The metrology, including accuracy, measurement repeatability (intra-serial precision condition of measurement), measurement precision, trueness of the measurement, and reproducibility of the measurement, measurement bias and errors of the measurements were discussed. [Copyright &y& Elsevier]

Abstract: Experimental and theoretical solid-state Raman spectroscopic study of five model derivatives of amino acids (AAs), crystallizing in the non-centrosymmetric space groups, with the number molecules per unit cell Z =1–8 were studied. The self-assembly association effects within the frame of crystals with P21, Pca21, and P212121, space groups and their effect on the Raman frequencies, within 10–0.3THz were discussed. The assignment of the spectroscopic properties and the hydrogen bond interactions, depending of the crystal packing of the model tyramine hemihydrate was performed. The paper aims to make a bridge between the methods for analysis of the optical phenomena within the THz-region, such as far-IR, Raman and THz-spectroscopy. The observed individual characteristic excitations of materials within THz-region, provided unique opportunity for chemical identification in solid-state. The specific advantages of each of the methods provided unique combination allowing both qualitative and quantitative analysis, especially of macro-components, and achievement of the analytical information at an extremely high degree of certainty towards the individual characteristics of each of the studied chemicals as properties of evidence, and would contributed in varying degrees to the evidence in the field of forensic chemical analysis. [Copyright &y& Elsevier]

Abstract: The molecular architecture design and physical properties of seven camptothecin (CPT) alkaloids, structurally related to irinotecan (CPT-11), substituted with the cyclic bulk N-aliphatic substituents at A-ring as well as their different protonated forms were studied. The correlation between the molecular geometry and physical properties of the neutral lactone form and different possible cationic forms was elucidated, using the electronic absorptions (EAs), circular dichroic (CD) and Raman spectroscopy within the far-IR region as well as electrospray ionization and matrix-assisted laser desorption/ionization mass spectrometry and nuclear magnetic resonance methods. The electronic structures, and properties of the neutral CPTs, their mono- and diprotonated forms as well as molecular ion fragments, obtained by the mass spectrometric data are predicted theoretically using the DFT method. [Copyright &y& Elsevier]

Abstract: A discussion on the possible application of the organic 5-sulfosalicylates as organic materials with tunable optical and non-linear-optical (NLO) properties is performed on the basis of the experimental crystallographic and spectroscopic methods such as single crystal X-ray diffraction, electronic absorption, diffuse reflectance and fluorescence spectroscopy in condense phase, conventional and linear-polarized IR- and Raman spectroscopy in solid-state. The model systems 5-sulfosalicylic acid dihydrate (1), 4-aminobenzamidinium bis(5-sulfosalicylicilate) monohydrate (2) and 5-sulfosalicylicilate salt of glycinamide (3), comparing with the as well as theoretical quantum chemical calculations of the systems neutral 5-sulfosalicylic acid (I), its mono-(Ia) and dianion (Ib), respectively. [Copyright &y& Elsevier]

The title compound, 2-(phenylethyl)ammonium hydrogensquarate hemihydrate, was synthesized and structurally and spectroscopically characterized by a single crystal X-ray diffraction and solid-state polarized IR spectroscopy of oriented colloids in a nematic host. The crystal structure consists of two crystallographically independent 2-(phenylethyl)ammonium cations, joined in a 2D hydrogen-bonded network with hydrogensquarate anions and solvent water molecules. Surprisingly, the crystallographically non-equivalent cations exhibit differing pseudo T and G trans configurations. [ABSTRACT FROM AUTHOR]

Abstract: Stereo-structural analysis and IR-bands assignment of the aromatic dipeptides l-tryrosyl-l-phenylalanine (Tyr-Phe), l-phenylalanyl-l-tyrosine (Phe-Tyr) and their hydrochloride salts have been carried out by means of IR-LD spectroscopy of oriented as nematic liquid crystal suspension solid samples. The experimental data are compared with known crystallographic ones and theoretical predicted geometries at RHF/ and UHF/6-31G**. [Copyright &y& Elsevier]

The structure of a mononuclear Au(III) complex of the dipeptide glycyl-S-serine (Gly-Ser) has been predicted using solid-state linear dichroic IR (IR-LD) spectroscopy, based on an orientation technique in a nematic liquid crystal suspension. Results are compared with data from 1H- and 13C-NMR, MS, elemental analysis, thermogravimetry and differential scanning calorimetry. The metal ion is coordinated as a tridentate through NH2, N (from deprotonated amide) and O (COO-) groups to form [Au(C5H9N2O4)Cl], with the fourth position of the square-planar coordination sphere being completed by a Cl- ion. [ABSTRACT FROM AUTHOR]

Abstract: Possibilities of linear-dichroic infrared (IR-LD) spectroscopy based on oriented solid samples as suspension in nematic liquid crystal have been applied for detailed experimental IR-band assignment and structural information of 2-[5,5-dimethyl-3-(2-phenyl-vinil)-cyclohex-2-enylidene]-malononitrile, 2-[5,5-dimethyl-3-[2-(2-methoxyphenyl)vinyl]cyclo-hex-2-enylidene]malononitrile and 2-[3-[2-(2,4-dimethoxyphenyl)vinyl]-5,5-dimethylcyclohex-2-enylidene]malononitrile. The data of last two compounds have been compared with known crystallographic ones, thus determining the validity of conclusions made. [Copyright &y& Elsevier]

A solid state, linear dichroic IR analysis of a mononuclear Au(III) complex of the tripeptide glycylmethioninylglycine (GlyMetGly) oriented in a nematic liquid crystal has been carried out. Structural results are compared with 1 H and 13 C NMR data. The ligand coordinates to Au(III) as a tridentate in [Au(C 9 H 17 N 3 O 4 S)Cl]Cl 2 , binding through S, and the N- and O-atoms of neighbouring CONH– and COO - groups. The fourth position is occupied by a terminal Cl - ligand. [ABSTRACT FROM AUTHOR]

Abstract: IR-LD spectroscopic data obtained by the orientated solid samples as a suspension in a nematic liquid crystal of 1-hydroxy-1,2,3-benzotriazole, 2-methyl-, 2-acetonitrilebenzimidazoles and their protonated salts have been presented. The stereo-structures have been predicted and compared with theoretical ones. The IR-characteristic bands assignments of all molecule systems have been achieved. [Copyright &y& Elsevier]

Abstract: Stereo structural characterization of methionine-containing tripeptides glycine-glycine-methionine (Gly-Gly-Met) and methionine-glycine-glycine (Met-Gly-Gly) is carried out by means of linear-dichroic infrared spectral analysis of oriented as nematic liquid crystal suspension solid samples. Thus obtained data are compared with theoretical ones received by ab initio calculations (Hartree-Fock level of theory and 6-31G** basis set). An IR-spectral characterization of both tripeptides is included as well. [Copyright &y& Elsevier]

Abstract: IR-spectroscopic and stereo-structural analysis of aromatic l-Tryptophan containing dipeptides l-Tryptophan–l-Tryptophan (Trp–Trp), l-Tyrosine–l-Tryptophan (Tyr–Trp) and cyclo(Trp–Trp) have been carried out by means of solid-state linear-dichroic infrared (IR-LD) spectroscopy of oriented as suspension in nematic liquid crystal solids. The experimental data have been compared with analogous ones of the simple amino acids l-Tyrosnine (l-Tyr) and l-Tryptophan (l-Trp). In cyclo(Trp–Trp), the IR-spectral changes towards the IR-ones of acyclic Trp–Trp have been determined. A theoretical analysis of Tyr–Trp at Hartree–Fock level of theory and 6-31G** basis set is also applied. [Copyright &y& Elsevier]

Abstract: Validation of reducing-difference procedure based on subtracting of non-polarized infrared (IR) spectra of n-component solid mixtures is presented. The accuracy and precision are established. The limits of detection are 3.0, 2.5, 1.5 and 1.0wt.% for 5-, 4-, 3-and 2-component mixtures, respectively. Smoothing procedures for IR spectral analysis, based on Savitzky–Golay or Fourier methods are applied as well. The mean values and relative standard deviations for peak position (ν i ) and integral absorbance (A i ) obtained by this data processing approach have been examined using Student''s t-test. [Copyright &y& Elsevier]

Abstract: By means of solid-state linear-dichroic infrared (IR-LD) spectroscopy the stereo-structures of dipeptides methionyl-histidine (Met-His) and histidyl-methionine (His-Met) are predicted, accompanied with a detailed experimental IR-characteristic bands assignment. The experimental results are compared and confirmed with theoretical structural ones, obtained by ab initio calculations at the Hartree–Fock level of theory and 6-31G**. [Copyright &y& Elsevier]

A new mononuclear Cu(II) complex of 4-aminopyridine (4AP), [Cu(4AP)4]Cl2·2CH3OH ( 1 ), was obtained and structurally characterized by single-crystal X-ray diffraction methods. The complex is square-planar involving four monodentate 4AP molecules coordinated through the Npy atoms. A solid-state linear-dichroic spectroscopic analysis (IR-LD) as a suspension in a nematic liquid crystal was carried out over the 4000–400?cm -1 range and determined stereochemical parameters compared crystallographic data. Detailed IR characteristics are reported. [ABSTRACT FROM AUTHOR]

Interaction between the S-Phe–S-Phe dipeptide (PP) and Au(III) leads to the formation of a yellow complex, [Au(PP)Cl3]Cl (1), with monodentate coordination of the dipeptide with Au(III) through one O atom of the COO - group. Three Cl - anions bond to the metal center as terminal ligands. The structure of 1 was obtained by comparative solid-state linear-dichroic infrared (LD-IR) spectroscopic analysis of a solid sample and the pure dipeptide S-Phe–S-Phe, both oriented in a nematic liquid crystal suspension. [ABSTRACT FROM AUTHOR]

Abstract: Solid-state linear dichroic infrared (IR-LD) spectral analysis of both monoclinic (form I) and orthorhombic (form II) polymorphs of paracetamol was carried out using an orientation technique as a nematic liquid crystal suspension. The so-called reducing-difference procedure for polarized spectra interpretation was applied and the obtained supramolecular stereo structural data of both modifications were compared with known crystallographic ones. A detailed vibration assignment of characteristic frequencies of forms I and II was also applied. A quantitative FT-IR spectral approach for monoclinic form determination in mixtures by the intensity ratio of 1610cm-1 peak (characteristic for both forms) to 1666cm-1 one (attributed to orthorhombic modification) was presented, as well. [Copyright &y& Elsevier]

Mononuclear Au(III) complexes of the peptides H-His-Met-OH (D) and H-Gly-Gly-Met-OH (T) and their N -protected forms Ac-His-Met-OH (Ac-D) and Ac-Gly-Gly-Met-OH (Ac-T) were structurally characterized by means of IR, MS and NMR. In the complexes with dipeptides [AuLCl 2 ]Cl (L = D or Ac-D), Au(III) is coordinated through S and imidazole N atoms from methionine and histidine fragments of the ligands forming macrochelate rings at mol ratio Au : L = 1 : 1. Additionally, Au(III) is coordinated by two terminal chloride ions in a square-planar arrangement. In complexes with the tripeptides [AuL′Cl] (L′ = T or Ac-T), however, the metal ion is coordinated in a tridentate fashion, through S and two N atoms, also at mol ratio M : L = 1 : 1. The fourth position of Au(III) is occupied by a Cl - ligand. [ABSTRACT FROM AUTHOR]

Abstract: A linear dichroic infrared (IR-LD) spectral analysis of solid 4-aminopyridine (4-AP) samples was carried out using two orientation techniques, i.e., as polycrystalline layers and in a nematic mesophase. The so-called reducing-difference procedure was used for the polarized IR-spectra interpretation. By achieving a more precise assignment of a part of the 4-AP characteristic frequencies, the obtained data proved a Fermi-resonance splitting of the symmetrical NH2-stretch and confirmed the predominant aromatic character of the pyridine ring. The possibilities of the difference IR-LD technique used for the study of the supramolecular solid-state structure are also illustrated. [Copyright &y& Elsevier]

The article presents information on the structure of the organic compound S-Phenyl 4-cyanothiobenzoate or C14H9NOS. The molecules of this compound exhibit a chiral non-planar structure in which the 4-cyanophenyl and S-phenyl rings are tilted at dihedral angles of 1.81 (2) and 72.49 (1)° with respect to the central thiocarbonate unit. The compound crystallizes in the non-centrosymmetric monoclinic space group P21 and participates in very weak intermolecular hydrogen bonds and its observed structure is in good agreement with those determined for other S-phenyl thiobenzoates.

During the last 2 decades it was proposed that atherogenesis was closely related to the homeostasis of homocysteine (hCys) and/or copper. We hypothesized that the physiological action of hCys may be connected with its ability to form complexes with Cu. Our results showed the presence of two different Cu–hCys complexes. At a molar ratio Cu:hCys 1:1, a blue complex most probably consistent with a tentative dimeric CuII2(hCys)2(H2O)2 formula was formed, with tetrahedral Cu coordination and anti-ferromagnetic properties. The redox processes between Cu(II) and hCys, in a molar ratio ≥1:3 led to formation of a second yellow CuIhCys complex. Both Cu–hCys complexes affected the metabolism of extracellular thiols more than hCys alone and inhibited glutathione peroxidase-1 activity and mRNA abundance. The biological action of hCys and Cu–hCys complexes involved remodeling and phosphorylation of focal adhesion complexes and paxillin. The adhesive interactions of monocytes with an endothelial monolayer led to the redistribution of both paxillin and F-actin after all treatments, but the diapedesis of monocytes through endothelial cell monolayer was both greater and faster in the presence of the tentative CuII2(hCys)2(H2O)2 complex. Together, these observations suggest that Cu–hCys complexes actively participate in the biochemical responses of endothelial cells that are involved in the aethiopathogenesis of atherosclerosis. [Copyright &y& Elsevier]