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We systematically studied the vibrational-resolved electronic spectra of group IV dichlorides using the Franck–Condon approximation combined with the Duschinsky and Herzberg–Teller effects in harmonic and anharmonic frameworks (only the simulation of absorption spectra includes the anharmonicity). Calculated results showed that the band shapes of simulated spectra are in accordance with those of the corresponding experimental or theoretical ones. We found that the symmetric bend mode in progression of absorption is the most active one, whereas the main contributor in photoelectron spectra is the symmetric stretching mode. Moreover, the Duschinsky and anharmonic effects exert weak influence on the absorption spectra, except for PbCl 2 molecule. The theoretical insights presented in this work are significant in understanding the photophysical properties of MCl 2 (M = C, Si, Ge, Sn, Pb) and studying the Herzberg–Teller and the anharmonic effects on the absorption spectra of new dichlorides of this main group. [ABSTRACT FROM AUTHOR]

Highlights: [•] The title ligand and its Ni(II) complex were synthesized and characterized. [•] Crystal structures of the two compounds were obtained. [•] DFT calculations of structure, NPA analysis and electronic spectra were performed. [•] Experimental structures and electronic spectra were compared with the predicted ones. [•] Thermodynamic properties of the two compounds were studies. [Copyright &y& Elsevier]

Highlights: [•] Transition metal complexes with cetirizine (CTZ) were synthesized and characterized. [•] Protonation equilibria were calculated for (CTZ) and thermodynamics were discussed. [•] Complex formation equilibria and speciation of binary M(II)–CTZ were investigated. [•] The biological activity of the free CTZ and its metal-chelates were investigated. [ABSTRACT FROM AUTHOR]

Abstract: The structures and some molecular properties of the complexes M(mnt)2 2− (M=Ni, Pd, Pt and Zn, Cd, Hg; mnt2− =deprotonated maleonitriledithiolate) have been studied by using density functional theory (DFT) B3LYP/LanL2DZ level of theory. Computed binding energies show that the sequences of binding strengths are Ni

Abstract: Piroxicam (PRX) has been widely studied in an attempt to elucidate the causes and mechanisms of its side effects, mainly the photo-toxicity. In this paper fluorescence spectra in non-protic solvents and different polarities were carried out along with theoretical calculations. Preliminary potential surfaces of the keto and enol forms were obtained at AM1 level of theory providing the most stable conformers, which had their structure re-optimized through the B3LYP/CEP-31G(d,p) method. From the optimized structures, the electronic spectra were calculated using the TD-DFT method in vacuum and including the solvent effect through the PCM method and a single water molecule near PRX. A new potential surface was constructed to the enol tautomer at DFT level and the most stable conformers were submitted to the QST2 calculations. The experimental data showed that in apolar media, the solution fluorescence is raised. Based on conformational analysis for the two tautomers, keto and enol, the results indicated that the PRX-enol is the main tautomer related to the drug fluorescence, which is reinforced by the spectra results, as well as the interconvertion barrier obtained from the QST2 calculations. The results suggest that the PRX one of the enol conformers presents great possibility of involvement in the photo-toxicity mechanisms. [Copyright &y& Elsevier]

Abstract: New bimetallic complex salts corresponding to the formulation [Ni(L)][MCl4] have been synthesized by the facile reaction between [Ni(L)](ClO4)2 and [MCl2(PPh3)2] in high yields {where M=Co(II), Zn(II), Hg(II) and L=3,7-bis(2-aminoethyl)-1,3,5,7-tetraazabicyclo(3.3.1)nonane}. The complexes were characterized by IR, electronic spectra, TGA/DSC, magnetic moment and conductivity measurements. The X-ray crystal structure for [Ni(L)][CoCl4] clearly establishes the cationic–anionic interaction. It crystallizes in the space group P1 with unit cell dimensions a =7.1740(15)Å, b =8.1583(16)Å and c =8.3102(16)Å. A square-planar geometry is evident for the [Ni(L)]2+ cation while the anion is found to be tetrahedral. A two-step thermolytic pattern is observed in the pyrolysis of the bimetallic complex salts. [Copyright &y& Elsevier]

Abstract: Experimental methods of infrared, Raman and electronic absorption spectroscopy and DFT calculations using B3LYP functionals and 6-31G** and 6-311++G** basis sets have been used to understand the structural and spectral characteristics of 2-pyranones, 6-phenyl-4-methylsulfanyl-2-oxo-2H-pyran and 6-phenyl-4-methylsulfanyl-2-oxo-2H-pyran-3-carbonitrile in the electronic ground (S0) and first excited (S1) states. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). Based on TD-DFT calculations using 6-31+G**5D basis set, an assignment of absorption peaks in the UV–VIS region has been suggested. The S1 state is found to be a 1(π,π*) state. A complete vibrational analysis has been attempted on the basis of experimental infrared and Raman spectra and calculated frequency and intensity of the vibrational bands and potential energy distribution over the internal coordinates. Characteristic vibrational bands of the 2-pyranone ring and methylsulfanyl and carbonyl groups have been identified. [Copyright &y& Elsevier]

Abstract: New stable Fe(III) complexes of tetraamide [N6], [N8] and [N10] macrocyclic ligands are reported. One of them, [N10] is dinucleating, with two Fe(III) nuclei in the macrocyclic cavities. The structural features have been discussed on the basis of analytical, ESI mass, FT-IR, electronic, 1H and 13C NMR spectral studies. Magnetic moment studies indicate presence of anti-ferromagnetically coupled (Fe3+–Fe3+ =S5/2–S5/2) spin–spin interactions in the dinuclear [N10] complex. 57Fe Mössbauer measurements confirm Fe(±3/2→±1/2) nuclear transitions supporting high–spin configuration of Fe(III) nuclei with the presence of Kramer''s double degeneracy. [Copyright &y& Elsevier]

Abstract: The laser produced spectrum of Si2 molecule is recorded for the first time using laser ablation technique in the region of 540–1010nm. About 110 bands are observed in the entire spectral region and all these bands are classified into three band systems, viz. E–X, F–X and G–X of Si2 molecule lying in the region of 814–1010nm, 630–900nm and 546–710nm, respectively. All these electronic transitions take place from ground state X3Σg − state. The molecular constants of all these states have been determined. [Copyright &y& Elsevier]

Abstract: The reaction between 2-hydrazinopyridine and ethylisothiocyanate produced 4-ethyl-1-(pyridin-2-yl) thiosemicarbazide (HEPTS). Its reaction with copper fluoride, chloride, bromide, acetate, nitrate, perchlorate, sulfate, carbonate, hydroxide and copper metal produced 15 Cu(II) complexes. The copper metal is easily oxidized in aqueous-ethanol solution of HEPTS giving [Cu2(EPTS)(H2O)3(OH)3]EtOH. Different complexes for the same anion were synthesized by controlling the heating time. Characterization by elemental, thermal, magnetic and spectral (electronic, IR, mass and ESR) studies showed the formation of mono-, di-, tri- and tetra nuclear complexes. The room temperature solid state ESR spectra of the complexes show an axial spectrum with ground state, suggesting distorted tetragonal geometry around Cu(II) center. The kinetic and thermodynamic parameters for the different decomposition steps in the complexes were calculated. HEPTS and its Cu(II) complexes showed high activity against gram negative bacteria; [Cu3(EPTS)2(EtOH)2Br4] has more activity. [Copyright &y& Elsevier]

Abstract: The molecular structure, electronic and infrared spectroscopic properties for the title complex Co(mnt)(5-NO2-phen) (mnt2− =maleonitriledithiolate, 5-NO2-phen=5-nitro-1,10-phenanthroline) were studied in this paper. With semi-empirical PM3 and non-empirical density functional theory (DFT) methods, the gaseous molecular geometry of the complex was optimized and corresponding vibrational spectra was obtained. The calculated results of structure and frequency from DFT were more reasonable than those from PM3, and the two methods were both agreed with the experimental values. A complete assignment to the IR spectra of such a complicated molecule has been exhibited. An electronic spectra was calculated by ZINDOS/S method. The results showed that the calculated values agreed with the observed ones. [Copyright &y& Elsevier]

Abstract: Two types of dinuclear copper(II) and nickel(II) complexes with two tetradentate N2O2 donor ligands 1,4-bis(1-anthranoylhydrazonoethyl)benzene (L1), 1,4-bis(1-salicyloylhydrazonoethyl)benzene (L2) and N,N′-bidentate heterocyclic base [1,10-phenonthroline (phen)] have been synthesized and characterized by elemental analysis, infrared spectra, UV–vis electronic absorption spectra and magnetic susceptibility measurements. The reaction of metal(II) acetates with the solution containing ligand and 1,10-phenonthroline in methanol gives mixed-ligand dinuclear metal(II) complexes with general formula [M2L(phen)2]Cl2 (L=L1 or L2), whereas, the ligands react with metal(II) acetates to form polymeric dinuclear complexes with general formula [(M2L2) n ] (L=L1 or L2). In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and amino groups of aroylhydrazone moiety do not participate in coordination. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes has been investigated. [Copyright &y& Elsevier]

Abstract: Sixteen Schiff bases obtained from the condensation of benzaldehyde or salicylaldehyde with various amines (aniline, 4-carboxyaniline, phenylhydrazine, 2,4-dinitrophenylhydrazine, ethylenediamine, hydrazine, o-phenylenediamine and 2,6-pyridinediamine) are studied with UV–vis spectroscopy to observe the effect of solvents, substituents and other structural factors on the spectra. The bands involving different electronic transitions are interpreted. Computerized analysis and multiple regression techniques were applied to calculate the regression and correlation coefficients based on the equation that relates peak position λ max to the solvent parameters that depend on the H-bonding ability, refractive index and dielectric constant of solvents. [Copyright &y& Elsevier]

Abstract: Cobalt(II) complexes of reduced glutathione (GSH) of general composition Na[Co(L)(X)]·nH2O (where H2L=GSH; X=Cl−, NO3 −, NCS−, CH3CO2 −, HCO2 −, ClO4 − and n =0–4) have been synthesized and characterised by elemental analyses, vibrational spectra, electronic spectra, magnetic susceptibility measurements, thermal studies and molecular modeling studies. Electronic spectra indicate planar geometry for all the complexes. Infrared spectra indicate the presence of H2O molecules (except perchlorate complex) in the complexes that has been supported by TG/DTA. The room temperature magnetic moment values for all complexes lie in the range of 2.60–2.80BM range indicating departure from spin only values due to second order Zeeman effect. Thermal decomposition of all the complexes proceeds via first order kinetics. The Na[Co(L)(Cl)]·2H2O complex has the minimum activation energy and Na[Co(L)(CH3CO2)]·3H2O has the maximum activation energy. The molecular modeling calculation for energy minimization optimizes geometry of the metal complexes. [Copyright &y& Elsevier]

Abstract: Two types of copper(II) and nickel(II) complexes derived from benzophenone anthranoylhydrazone (L1), 2-acetonaftanone anthranoylhydrazone (L2), 4-phenylacetonaftonone anthranoylhydrazone (L3), benzophenone salicyoylhydrazone (L4), 2-acetonaftanon salicyoylhydrazone (L5), 4-phenylacetonaftanon salicyoylhydrazone (L6) and bidentate heterocyclic base [1,10-phenanthroline (phen)] with general stoichiometry [ML2] and [ML(phen)]Cl have been synthesized and characterized by elemental analysis, infrared spectra, UV–vis electronic absorption spectra and magnetic susceptibility measurements. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes have been investigated. According to the IR spectra, the ligands act as monobasic bidentate and coordination takes place in the enol tautomeric form. [Copyright &y& Elsevier]

Abstract: The molecular structure and binding, as well as infrared and electronic spectroscopic properties for the title complex Cu(mnt)(dmbpy)(mnt2− =maleonitriledithiolate, dmbpy=4,4′-dimethyl-2,2′-bipyridine) were studied in this paper. With semi-empirical PM3 and non-empirical DFT (B3LYP/6-311G*) methods, the molecular geometry of the complex was optimized and corresponding vibrational spectra in the gaseous state were obtained. The calculated results derived from DFT were more reasonable than those from PM3. The point group of Cu(mnt)(dmbpy) in isolated gaseous state was C 2, in which CuII adopted a distorted tetrahedral geometry and the dihedral angle between the N2Cu and S2Cu planes was about 29.814°. And a complete assignment to the IR spectra of such a complicated molecule was exhibited. With ZINDO/S method an electronic spectrum was calculated. The results showed that the calculated values generally agreed with the observed ones. And a detailed explain was made on its electronic spectra. [Copyright &y& Elsevier]

From the critical analyses of Raman and infrared spectra, different normal modes of vibration of diphenylmethane (DPM) have been identified. The near ultraviolet absorption spectra of the molecule are found to consist of two band systems, one around 220 nm and the other around 270 nm with respective f-values 5.23×10-2 and 6.44×10-3. The first system is broad and shows few diffuse structures, whereas the later one exhibits very well-resolved structure. They are respectively assigned as 1La and 1Lb bands. The Raman excitation profiles of several normal modes have been analyzed to get structural and other information of different excited electronic states. [Copyright &y& Elsevier]

New polymeric complexes of Cu(II), Co(II), Ni(II) and UO2(II) with 5-(21-carboxyphenylazo)-8-hydroxyquinoline (LH2) have been prepared and characterized on the basis of analytical, magnetic, 1H NMR, EPR and electronic spectral studies. Tentative structures for the polymeric complexes are proposed. The important infrared (IR) bands and the main 1H NMR signals are assigned and discussed relative to the molecular structure. EPR spectrum of copper(II) complex has been studied with a view to assigning their stereochemistries. Various EPR parameters have been calculated. Each metal has six-coordinates in an octahedral environment. The ligand acts as a dibasic (bis-bidentate chelating agent coordinating through CN, N&z.dbnd6;N, COOH and OH groups by replacement of a proton from the two latter groups. Considerable interest has also been focused on the synthesis of the azo compounds and its polymeric metal complex due to its wide potential applications. The thermal decomposition behavior of the complexes is also discussed. [Copyright &y& Elsevier]

The electronic spectra of three azo cinnoline derivatives have been studied in pure and mixed organic solvents of different characteristics as well as the effect of concentration of the compounds in the different solvents. The different bands observed have been assigned to the proper electronic transition. The longer wavelength band displayed by the para nitro cinnoline derivative in dimethylformamide (DMF) solution is assigned to an intermolecular CT transition. The solvated H-bonding complexes formed between DMF and the para nitro derivative were investigated. ΔG and Kf values of these complexes have been determined. The acidity constants of the para nitro compound were determined from the spectra in aquous-methanolic solution of varying pH values. The effect of temperature on the longer wavelength visible band of p-NO2 has been investigated. [Copyright &y& Elsevier]

Electronic absorption spectra of 1,2-diamino-9,10-anthraquinone (12DAAQ), 1,4-diamino-9,10-anthraquinone (14DAAQ), 1,5-diamino-9,10-anthraquinone (15DAAQ), and 2,6-diamino-9,10-anthraquinone (26DAAQ) are investigated. Molecular geometries of the amino anthraquinones in the ground state are optimized using the semiempirical ZINDO/1 and AM1 methods without imposing any symmetry constraints. The ground state geometries of all the molecular systems are found to be planar. For interpretation of the spectra, ZINDO/S-CI and AM1-CI calculations employing singly excited configuration using the completely optimized geometry are carried out. Such calculations on the electronic spectra of amino anthraquinones are carried out for the first time. On the basis of these calculations, the assignment of the spectra are successfully made. [Copyright &y& Elsevier]

Abstract: Statistical analysis is applied to study the solvatochromic effects using the solvent parameters (regressors) influencing the spectral shifts in the electronic spectra. The data pointed to eliminate the non-significant parameters and the aberrant points (for which supplemental interactions were neglected in used theories) from those supposed to multi-linear regression. A BASIC program permits to follow these desiderates step by step. In order to exemplify the steps of regression, the wavenumbers of the maximum π–π* absorption band of three benzene derivatives in various solvents were used. [Copyright &y& Elsevier]