Spectra Of Bis Research Articles

Molecular conformational analysis, vibrational spectra, NBO, NLO analysis and molecular docking study of bis[(E)-anthranyl-9-acrylic]anhydride based on density functional theory calculations

FT-IR and FT-Raman spectra of bis[(E)-anthranyl-9-acrylic]anhydride were recorded and analyzed. The conformational behavior is also investigated. The vibrational wave numbers were calculated using density functional theory (DFT) quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in Infrared and Raman spectra. Potential energy distribution was done using GAR2PED program. The geometrical parameters are compared with related structures. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using Natural Bonding Orbital (NBO) analysis. The Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) analysis are used to determine the charge transfer within the molecule. Molecular Electrostatic Potential (MEP) was performed by the DFT method. The calculated first hyperpolarizability of the title compound is comparable with the reported values of similar derivatives and is 4.23 times that of the standard nonlinear optical (NLO) material urea and the title compound and its derivatives are an attractive object for future studies of nonlinear optical properties. To evaluate the in silico antitumor activity of the title compound molecular docking studies were carried out against protein Bcl-xL. The 1H-NMR spectrum is also reported.

Structure and IR spectra of bis(thiourea)cadmium sulfate according to quantum-chemical calculation data

The structures of seven isomers of the [Cd(thio)2SO4] complex have been determined in the framework of density functional theory. The structures of molecular orbitals, charge distribution, and other characteristics of the isomers have been calculated. Natural bond orbital analysis of the chemical bond inside the coordination polyhedron has been performed. The experimental IR spectrum of crystalline [Cd(thio)2SO4) and the calculated IR spectrum of the isolated complex have been compared.

Chlorination of geminal bis(alkoxy-NNO-azoxy) compounds with sodium hypochlorite

Chlorination of geminal bis(alkoxy-NNO-azoxy) compounds with sodium hypochlorite involves the central carbon atom and gives 1,1-bis(alkoxy-NNO-azoxy)-1-chloroalkanes with high yield. Dichlorobis-(methoxy-NNO-azoxy)methane oxidizes sodium iodide to elemental iodine. The signal from the central carbon atom in the 13C NMR spectra of bis(alkoxy-NNO-azoxy)dichloromethanes is broadened and displaced downfield relative to those of the initial compounds.

Infrared spectra of bis(trifluoromethanesulfonyl)imide based ionic liquids: Experiments and DFT simulations

We measured the far- and mid-infrared spectra of three ionic liquids having bis(trifluoromethanesulfonyl)imide anions and three different cations of the families of pyrrolidinium and ammmonium ions. The molecular vibrations of the individual ions were calculated by means of DFT theory at the B3LYP/6-31G** level: we found good agreement between the experimental and the computed frequencies. The infrared lines are ascribable to molecular vibrations of the single ions, suggesting an extremely weak interaction between anions and cations. The spectral lines found experimentally between 760 and 1050cm−1 are fingerprints for different cations. The comparison with the calculated frequencies allows the assignment of the experimental spectral lines to specific molecular vibrations of anions and for the first time of the specific cations of the measured ionic liquids.

Theoretical and Experimental Vibrational Spectroscopic Investigation of Two R1R2-Diphenylsilyl-Containing Monomers and Their Optically Active Derivative Polymer

FT-IR and Raman spectra of bis(4-aminophenyl)diphenylsilane (DIA) and a dicarboxylic acid containing the imide function and a L-alanine moiety (L-ALA) and their resultant polymer (PALA) were recorded in the 500-4000 cm(-1) and 400-3800 cm(-1) regions, respectively. The optically active poly(imide-amide) obtained has two sp(3) carbons in the main chain, favoring its flexibility. Raman analysis identifies the fluorescence produced by the electronic conjugation between the aromatic rings and the amidic groups, which affects the molecular fine structure. Thus, the theoretical study of the vibrational patterns has become a support and a complementary technique for the characterization of this fluorescent system. The optimized molecular geometry of the monomers and the polymeric unit using B3LYP and HF methods at the 6-31G(d) level of theory were used for the vibrational assignments. Thus, the small variations between the calculated and experimental vibration values could be related to possible intra- and/or intermolecular interactions or to the existence of a charge transfer phenomena between a donor or acceptor group within the system.

Structure and vibrational spectra of melaminium bis(trifluoroacetate) trihydrate: FT-IR, FT-Raman and quantum chemical calculations

Melaminium bis(trifluoroacetate) trihydrate (MTFA), an organic material has been synthesized and single crystals of MTFA have been grown by the slow solvent evaporation method at room temperature. X-ray powder diffraction analysis confirms that MTFA crystal belongs to the monoclinic system with space group P2/c. The molecular geometry, vibrational frequencies and intensity of the vibrational bands have been interpreted with the aid of structure optimization based on density functional theory (DFT) B3LYP method with 6-311G(d,p) and 6-311++G(d,p) basis sets. The X-ray diffraction data have been compared with the data of optimized molecular structure. The theoretical results show that the crystal structure can be reproduced by optimized geometry and the vibrational frequencies show good agreement with the experimental values. The nuclear magnetic resonance (NMR) chemical shift of the molecule has been calculated by the gauge independent atomic orbital (GIAO) method and compared with experimental results. HOMO–LUMO, and other related molecular and electronic properties are calculated. The Mulliken and NBO charges have also been calculated and interpreted.

FT-IR and Raman spectra and DFT calculations on bis(L-histidinato)nickel(II) monohydrate

In this work the Fourier transform infrared and the Raman spectra of bis(L-hisidinato)nickel(II) monohydrate were recorded at room temperature. Optimized geometry and vibrational frequencies were obtained by means of Density Functional Theory (DFT). Experimental and theoretical vibrational spectra were compared and a complete analysis of the modes was done in terms of the Potential Energy Distribution (PED).

Stable Electrophosphorescent Emission of Fluorenyltrifluoromethyl-Pyridine Iridium 2-Picolinic Acid at High Concentration

Emission spectrum of bis [2-(9, 9-diethylfluoren-2-yl)-5-trifluoromethylpyridinto-C3, iridium (2-picolinic acid) (fl-5CF3-py)2Ir (pic) in THF was 572 nm. Two weak UV absorption bands can be assigned to spin-allowed singlet metal-to-ligand charge transfer (1MLCT) and spin-forbidden 3MLCT transitions. The organic light-emitting devices A ITO/PEDOT: PSS/PBD: PVK: (fl-5CF3- py)2Ir (pic) (12 %) /LiF/Al, B ITO/PEDOT:PSS/PBD: PVK: (fl-5CF3-py)2Ir (pic) (2 %) /TPBi/LiF/Al and C ITO/PEDOT:PSS/PBD: PVK: (fl-5CF3-py)2Ir (pic) (12 %) /TPBi/LiF/Al were fabricated using iridium complex as emitter dopant with electroluminescent spectra at 576, 572 and 576 nm, respectively. Devices A, B and C exhibited maximum luminance of 983 cd/m2 (at 10 V), 3132 cd/m2 (18 V) and 9876 cd/m2 (12V), respectively. Device C exhibited more efficient emission. The devices had excellent stability even at the high concentration.

Orange Electrophosphorescence of 2-(9, 9-Diethylfluoren-2-yl)-5- Trifluoromethylpyridine Iridium Complex

Emission spectrum of Iridium complex bis [2-(9, 9-diethylfluoren-2-yl)-5-trifluoromethyl-pyridinto-C3, iridium (acetylacetonate) (fl-5CF3-py)2Ir (acac) in THF was 589 nm. Two weak UV absorption bands can be assigned to spin-allowed singlet metal-to-ligand charge transfer (1MLCT) and spin-forbidden 3MLCT transitions. The organic light-emitting devices A ITO/PEDOT: PSS/PBD: PVK: (fl-5CF3-py)2Ir (acac) (8 %) /LiF/Al and B ITO/PEDOT:PSS/PBD: PVK: (fl-5CF3-py)2Ir (acac) (8 %) /TPBi/LiF/Al were fabricated using iridium complex as emitter dopant with electro-luminescent spectra at 592 and 588 nm at the bias voltages of 9, 11 and 13V. Devices A and B exhibited luminance of 5265 (at 15 V) and 4098 cd/m2 with Commission International de LEclairage (CIE) coordinates of (0.5805, 0.4185) and (0.5815, 0.4176), respectively. Device B (with TPBi) emitted orange light more efficiently than Device A (without TPBi).

Molecular structure, spectroscopic (FT-IR, FT-Raman, UV–vis), NBO, thermochemistry analysis of bis(thiourea)zinc(II) chloride crystals

The experimental and theoretical studies on the molecular structure and vibrational spectra of bis(thiourea)zinc(II) chloride (BTZC) crystals were investigated. The Fourier transform infrared, Fourier transform Raman and UV–vis spectra of BTZC were recorded. The molecular geometry and vibrational frequencies of BTZC in the ground state were calculated by using B3LYP with LANL2DZ as basis set. Comparison of the observed structural parameters of BTZC with single-crystal X-ray studies yields a good agreement. Vibrational analysis of the simultaneous IR and Raman activation of the Zn–Cl stretching mode in the molecule provides the evidence for the charge transfer interaction taking place within the molecule. The energy and oscillator strength are calculated by time-dependent density functional theory. The simulated spectra satisfactorily coincide with the experimental spectra.

Experimental and theoretical vibrational study of methylene bis(thiocyanate), CH2(SCN)2. A comparison with thiocyanogen, (SCN)2

The infrared and Raman spectra of methylene bis(thiocyanate), CH2(SCN)2, were obtained. The observed bands were assigned to the different normal modes of vibration using the results of a DFT calculation of the molecular vibrational properties. These results and the experimental data were used to define a Scaled Quantum Mechanics force field for the molecule. A similar treatment was applied to the thiocyanogen molecule, (SCN)2, for which the experimental frequencies were already reported in the literature. The sets of internal force constants for both molecules show very similar values.

Molecular structure and vibrational spectra of Bis(melaminium) terephthalate dihydrate: A DFT computational study

The experimental and theoretical vibrational spectra of Bis(melaminium) terephthalate dihydrate were studied. The Fourier transform infrared (FT-IR) spectra of the Bis(melaminium) terephthalate dihydrate and its deuterated analogue were recorded in the solid phase. The molecular geometry and vibrational frequencies of Bis(melaminium) terephthalate dihydrate in the ground state have been calculated by using the density functional method (B3LYP) with 6-31++G(d,p) basis set. The results of the optimized molecular structure are presented and compared with the experimental X-ray diffraction. The molecule contains the weak hydrogen bonds of NH⋯O, NH⋯N and OH⋯O types, and those bonds are calculated with DFT method. In addition, molecular electrostatic potential, frontier molecular orbitals and natural bond orbital analysis of the title compound were investigated by theoretical calculations. The lack of the second harmonic generation (SHG) confirms the presence of macroscopic center of inversion.

Vibrational Study of Dipotassium Zinc Bis(Dihydrogendiphosphate) Dihydrate, K2ZN(H2P2O7)2·2H2O

Infrared and Raman spectra of dipotassium zinc bis(dihydrogendiphosphate) dihydrate, K2Zn(H2P2O7)2 .2H2O have been collected and interpreted using factor group analysis. Noncoincidence of the Raman and infrared spectra bands confirms a centrosymmetric structure for K2Zn(H2P2O7)2 .2H2O previously investigated by X-ray structural study, as well as the joint appearance of νas POP and νs POP point to a bent POP configuration.

Polarity and vibrational spectra of bis(2-phenylethyl)- and bis(2-phenylpropyl)phosphine selenides

Polarity and vibrational spectra of bis(2-phenylethyl)- and bis(2-phenylpropyl)phosphine selenides

Theoretical insights into the visible near‐infrared absorption spectra of Bis(hexafluoroacetylacetonate) copper(II) in pyridine

AbstractThe density functional theory calculations were performed to investigate the specific solvent effects on the optical absorption spectrum of copper(II) hexafluoroacetylacetonate complex in pyridine. The effects of single and double coordination of pyridine molecules at axial position of bis(hexafluoroacetylacetonate) copper(II) indicate that both positions and intensities of 3d–3d electronic transitions are strongly dependent on the coordination environment around the copper(II) complex. The results indicate that the nature of the electron‐acceptor atoms in the equatorial ligands plays an important role in the number of solvent molecules in the first solvation shell of copper(II) acac systems. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

Binuclear copper(II) complexes of 1-amidino-O-alkylurea (alkyl = n-propyl, n-butyl, or i-butyl) and vanadate: an EPR study

Five new complexes of bis(1-amidino-O-alkylurea)Cu(II)vanadate where alkyl = methyl, ethyl, n-propyl, n-butyl or i-butyl have been synthesized by reaction of ammonium metavanadate with bis(1-amidino-O-alkylurea)Cu(II)perchlorate complexes. Electron paramagnetic resonance (EPR) spectra of bis(1-amidino-O-n-propylurea)Cu(II)vanadate (1), bis(1-amidino-O-n-butylurea)Cu(II)vanadate (2) and bis(1-amidino-O-i-butylurea)Cu(II)vanadate (3) gave half-field signal (ΔM s = ±2) ca 1623G, in addition to fine structure due to zero field splitting (ZFS) characteristics of the S = 1 system. From the observed ZFS the average Cu–Cu distance was estimated. The isotropic exchange constant J was evaluated by recording EPR spectra at different temperatures. The photoacoustic signal of the complexes indicated square-planar geometry around Cu2+. X-ray powder diffraction studies on 2 suggested orthorhombic structure with unit cell dimensions a = 21.11 Å, b = 24.11 Å, c = 27.11 Å, α = β = γ = 90°. The crystal structure of bis(1-amidino-O-n-butylurea)Cu(II)perchlorate is also reported.

Do electrospray mass spectra of surfactants mirror their aggregation state in solution?

One important feature in the gas phase chemistry of surfactants is to ascertain whether their aggregates produced by electrospray ionization reflect those formed in the starting solution. With this aim, we have performed ESI-MS, ESI-MS/MS and ER-MS spectra of bis(2-ethylhexyl)sulfosuccinate (AOTNa) solutions in different solvents, i.e. water, water/methanol, methanol and n-hexane. The results clearly indicate that, notwithstanding the strongly different aggregation state in solution (direct micelles in water and in water/methanol, molecular dispersion in methanol and reverse micelles in n-hexane) and marked effects of the solvent polarity on the total ionic current, the surfactant aggregates in gas phase show identical structural features. Analogous conclusions can be drawn analyzing the infrared multiple photon dissociation (IRMPD) spectra of AOTNa solutions in water/methanol and n-hexane. Moreover, according to the idea that gas phase can be considered an apolar environment par excellence, data consistently suggest a reverse micelle-like aggregation. Some peculiarities of the mechanisms leading to aggregate formation through electrospray ionization of surfactant solutions in solvent media with different polarity have been also discussed.

Electronic structures of organometallic complexes of f elements LXXVI: Correlation of experimental and calculated (on the basis of density functional theory) vibrational spectra of bis(η 5-cyclopentadienyl)ruthenium and bis(η 5-pentamethylcyclopentadienyl)ruthenium

Previous empirical assignments of the normal modes of Ru(η 5-C 5H 5) 2 were checked against the results of a calculation applying density functional theory (DFT). After some reassignments, following those recently suggested for Fe(η 5-C 5H 5) 2 (after theoretical model calculations), a satisfactory agreement was observed. Recently communicated polarized Raman spectra of an oriented Ru(η 5-C 5Me 5) 2 single crystal were used here for the identification of the irreducible representations of a number of Raman active normal modes (assuming molecular D 5h symmetry) which agree well with the results of the DFT calculation. The energies of IR active fundamental vibrations, extracted from recently communicated FIR/MIR spectra (pellets), were correlated with comparable energies of IR allowed irreducible representations of the DFT calculation and assigned. Both the skeletal and the intra-ligand normal modes could be correlated with the idealized standard motions (ν is) of the model sandwich complex Ru(C 5C 5) 2, and previous assignments had to be revised. Neglecting the νCH vibrations (which are off by ca. 50 cm −1) an r.m.s. deviation of 9.8 cm −1 (for 47 assignments) of the remaining normal modes could be achieved.

Rotationally Resolved C2 Symmetric Conformers of Bis-(4-hydroxyphenyl)methane: Prototypical Examples of Excitonic Coupling in the S1 and S2 Electronic States

Rotationally resolved microwave and ultraviolet spectra of jet-cooled bis-(4-hydroxyphenyl)methane (b4HPM) have been obtained using Fourier-transform microwave and UV laser/molecular beam spectrometers. A recent vibronic level study of b4HPM [Rodrigo, C. P.; Müller, C. W.; Pillsbury, N. R.; James, W. H., III; Plusquellic, D. F.; Zwier, T. S. J. Chem. Phys. 2011, 134, 164312] has assigned two conformers distinguished by the orientation of the in-plane OH groups and has identified two excitonic origins in each conformer. In the present study, the rotationally resolved bands of all four states have been well-fit to asymmetric rotor Hamiltonians. For the lower exciton (S(1)) levels, the transition dipole moment (TDM) orientations are perpendicular to the C(2) symmetry axes and consist of 41(2):59(2) and 34(2):66(2)% a:c hybrid-type character. The S(1) levels are therefore delocalized states of B symmetry and represent the antisymmetric combinations of the zero-order locally excited states of the p-cresol-like chromophores. The TDM polarizations of bands located at ≈132 cm(-1) above the S(1) origins are exclusively b-type and identify them as the upper exciton S(2) origin levels of A symmetry. The TDM orientations and the relative band strengths from the vibronic study have been analyzed within a dipole-dipole coupling model in terms of the localized TDM orientations, μ(loc), on the two chromophores. The out-of-the-ring plane angles of μ(loc) are both near 20° and are similar to results for diphenylmethane [Stearns, J. A.; Pillsbury, N. R.; Douglass, K. O.; Müller, C. W.; Zwier, T. S.; Plusquellic, D. F. J. Chem. Phys. 2008, 129, 224305]. The in-plane angles are, however, rotated by 14 and 18° relative to DPM and, in part, explain the smaller than expected exciton splittings of these two conformers.

Structure and optical spectra of bis(pyrrol-2-ylmethyleneamine) complexes: A DFT and TDDFT study of the self-assembly complexes of bis(pyrrol-2-ylmethyleneamine) ligands linked by alkyl spacers with Cu(II)

The UV-Vis absorption spectra of self-assembly Cu (II) complexes for bis(pyrrol-2-ylmethyleneamine) linked by alkyl(CH2)n(n = 2,3,4,6) spacers were recorded. The ground-state geometries and electronic structures were investigated by density functional theory employing generalized-gradient approximation Perdew-Burke-Ernzerhof (PBE) and hybrid B3LYP (20% Ex,HF)and PBE0 (25% Ex,HF) functional, in conjugation with four basis set combinations.[BS1:6-31G(d); BS2:Lanl2dz for Cu and 6-31G(d) for C,H,N; BS3:6-31+G(d); BS4:6-311+G(d,p) for C,H,N and Lanl2dz for Cu]. Compared the optimized geometries with XRD structures, it was found that the choice of methods appeared to have a more pronounced effect on structure than that of the basis set. PBE0/BS4 optimized geometries provide the best agreement with XRD experimental results and the mean absolute errors for bond length is 0.018 A and for bond angle is 2.1°. Transition excited states of complexes 1–4 in the gas phase and in CH2ClCH2Cl solution have been studied by the time-dependent density functional theory in conjugated with the Polarizable Continuum Model. Pure PBE and hybrid B3LYP, PBE0 functionals, as well as BS1, BS2, and BS5 [6-311++G (d,p)] were selected. Calculations indicate that PBE functional provides more accurate descriptions on main UV-vis absorptions than B3LYP and PBE0 functionals. The strongest absorption bands located at 338–356 nm are due to intraligand charge transfer (ILCT) transitions, a mixed-character ILCT + metal-ligand charge transfer (MLCT) absorptions are calculated at 280–291 nm, the shoulder bands located at 250–257 nm mainly arise from MLCT or ligand-metal charge transfer transitions. Alkyl spacer does not play a crucial role on the main electron transitions. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2011