Synthesis, spectroscopic and electronic characterizations of two half sandwich ruthenium(II) complexes with 2-(2′-hydroxyphenyl)-benzoxazole and 4-picolinic acid ligands

The [(C₆H₆)RuCl(HPB)] and [(C₆H₆)RuCl₂(C₅H₄NCOOH)] complexes have been prepared and studied by IR, UV-Vis spectroscopy and X-ray crystallography. The complexes was prepared in reaction of [(C₆H₆)RuCl₂]₂ with 2-(2′-hydroxyphenyl)-benzoxazole or 4-picolinic acid in methanol. The electronic spectra of the obtained compounds have been calculated using the TDDFT method. The luminescence property of the half sandwich complex [(C₆H₆)RuCl(HPB)] was studied by the DFT method and the mechanism was suggested.     

用密度泛函理论研究一种新型有机硅化合物异构体的振动光谱

在B3LYP/6-31＋G(d)的水平上, 对两种含有手性Si原子的新型有机硅单体Si₂(CH₃)₂H₂N₂(C₂H₅)₄和Si₄(CH₃)₄H₄N₂(C₆H₅)₂的几种异构体进行了研究, 在全参量几何构型优化的基础上, 进行了简谐振动频率计算, 同时对所研究的体系进行了热力学性质和低能激发态的含时密度泛函理论(TDDFT)计算. 理论计算表明, 构象异构体之间的红外光谱差异不大, 热力学和低能激发态性质也相似; 顺/反结构相似的异构体之间红外光谱差异不大, 但热力学和低能激发态性质却呈现差异; 旋光异构体或顺/反结构相差较大的异构体之间, 红外光谱和热力学及低能激发态性质有明显的差异. 从理论上解释了实验红外光谱中Si—H振动峰的裂分是由异构体的存在所致, 并找到裂分峰所对应的异构结构. Si—H键振动频率与其键长相关.     

Assignment on the X,A, B,C, and D states of the C6H5Br+ cation based on high‐level calculations

Geometries, frequencies, and energies of the 1²B₁, 1²A₂, 1²B₂, 2²B₁, 2²B₂, and 1²A₁, of the C₆H₅Br⁺ ion were calculated by using CASSCF and CASPT2 methods in conjunction with an ANO‐RCC basis. The CASPT2//CASSCF adiabatic excitation energies and CASPT2 relative energies for the six states are in good agreement with experiment. The X, A, B, C, and D electronic states of the C₆H₅Br⁺ ion were assigned to be X²B₁, A²A₂, B²B₂, C²B₁, and D²B₂ based on the CASSCF and CASPT2 calculations. The assignment on the D state of the C₆H₅Br⁺ ion is different from the previously published works. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010     

A tandem mass spectrometric investigation of (C2H5)2X+ ions (X = Cl,Br, I): The involvement of classical and nonclassical ethyl structures therein

The formation of diethyl halonium ions (C₂H₅)₂X⁺ (X = Cl, Br, I) by a variety of ion-molecule reactions is described. The dissociation characteristics (metastable and collision-induced dissociation mass spectra) of these ions and their isomers were studied in detail. Some of the neutral fragmentation products were examined by their collision-induced dissociative ionization mass spectra. The participation of classical (1, CH₃CH₂X⁺CH₂CH₃) and nonclassical forms of the ions was considered. Dissociation reactions for which loss of positional identity of H-D atoms took place, for example C₂H₄ loss (a common fragmentation of metastable ions) and C₂H₅ ⁺ formation, were interpreted as involving nonclassical ions, 2. It was concluded that the ion-molecule reactions produced both ion structures, but in different halogen-dependent proportions. For (C₂H₅)₂C1⁺ ions, 2 is the major species, for (C₂H₅)₂Br⁺ both 1- and 2-type ions are generated, whereas for (C₂H₅)₂I⁺ the classical form 1 must be the predominant structure.     

Solvent extraction behaviour of iodine and bromine in aqueous-organic systems,analogy with radioactive decay

The extraction of iodine and bromine under various conditions from their saturated aqueous solutions by CCl₄, C₆H₆ and o-xylene has been studied. The data obtained from the experiments carried out at various temperatures, for H₂O(I₂)−CCl₄ and H₂O(I₂)−C₆H₆ systems, exhibit an Arrhenius behaviour. The overall activation energy calculated for the extraction in the H₂O(I₂)−CCl₄ system, 650±50 cal·mol⁻¹ is lower than that of H₂O(I₂)−C₆H₆, 3600±300 cal·mol⁻¹. The use of the solubility parameter for the interpretation of the data in the extraction of iodine is investigated. The data obtained in multiple extractions are treated by using the analogy between extraction and radioactive decay. The half number of extraction for each system is determined. The complex curves obtained in the H₂O(I₂)−CCl₄ and H₂O(I₂) −Br₂)−CCl₄ systems are resolved into two components.     

Komplexe des zweiwertigen Molybdäns,Derivate des Oktahalodimolybdat(II)-Ions, 2. Mitt.

Cs₃Mo₂Br₇·2H₂O reacts with pyridine at room temperature giving Mo₂Br₄(C₅H₅N)₄. Dry ammonia substitutes pyridine from Mo₂ X ₄(C₅H₅N)₄ (X=Cl, Br) at 100°C. The resulting products are Mo₂ X ₄(NH₃)₄. No reaction takes place under the same experimental conditions with 2.2′-bipyridine complexes Mo₂ X ₄(C₁₀N₂H₈)₂. Mo₂Br₄(C₅H₅N)₄ can also be obtained reacting Mo₂Cl₄(C₅H₅N)₄ with LiBr. New compounds were identified on the basis of IR spectra, powder patterns, magnetic measurements and chemical evidence.     

Some new unsymmetrical diimino tetradentate schiff base derived from 3,4-Diaminobenzophenone: Synthesis, characterization and the formation constant of Ni(II) and Cu(II) complexes

Some new unsymmetrical diimino tetradentate Schiff bases derived from 3,4-diaminobenzophenone, (N-salicyliden-N′-5- OMe.salycyliden)-3,4-diaminobenzophenone (H₂sal-5-OMe.sal.dabp) (H₂L¹), (H₂sal-5-Br.sal.dabp) (H₂L²), (H₂sal-5-Cl.sal.dabp) (H₂L³) and (H₂sal-5-NO₂.sal.dabp) (H₂L⁴) and their Ni(II) and Cu(II) complexes were synthesized and characterized by elemental analysis, IR, ¹H NMR, UV-Vis spectra and mass spectra. The thermodynamic formation constants of the complexes were determined spectrophotometrically at constant ionic strength (0.1 M NaClO₄) at 25 °C in DMF and their free energies of formation were calculated at 25 °C.     

Die Hydrohalogenierung von Hexaphenyldigerman und die Schwingungsspektren einiger Ge2(C6H5) n X6−n -Verbindungen

The reactions of Ge₂(C₆H₅)₆ with HCl and HBr lead in nearly quantitative yields to the 1,1,2,2-tetrahalo derivatives Cl₂(C₆H₅)GeGe(C₆H₅)Cl₂ (I) and Br₂(C₆H₅)GeGe(C₆H₅)Br₂ (II), resp. The Si?Ge bond of (C₆H₅)₃SiGe(C₆H₅)₃ is cleaved under the conditions of hydrohalogenation. The vibrational spectra of Ge₂Br₆, Ge₂(C₆H₅)₆, I, and II are reported. The influence of vibrational coupling on ν GeGe in these compounds is discussed in detail, including vibrational calculations.     

Synthese und Kristallstruktur von Blei(II)‐oxidhalogenid‐Alkoholaten mit unterschiedlichen Verknüpfungsvarianten von Pb4O4‐Heterokubaneinheiten

Synthesis and Crystal Structure Determination of Lead(II) Oxide Halide Alcoholates with Different Connectivity of Pb₄O₄ Heterocubane‐like Subunits The reaction of red lead(II) oxide (Litharge) and lead(II) halide (Cl^? and Br^?) with diethylene glycole at a temperature of 180 °C leads to the isotypic compounds [Pb₆(C₄H₈O₃)O₂Cl₆] (1) and [Pb₆(C₄H₈O₃)O₂Br₆] (2) . In a similar synthesis with PbI₂ as educt at temperature of 160 °C the two modifications β‐[Pb₆(C₄H₈O₃)O₂I₆] (3) and α‐[Pb₆(C₄H₈O₃)O₂I₆] (4) were found, whereas at a reaction temperature of 180 °C [Pb₉(C₂H₄O₂)(C₄H₈O₃)O₃I₈] (5) was surprisingly obtained as product. The X‐ray diffraction data show that at a temperature of 180 °C a splitting of the ether took place. The cited compounds show cubane like subunits built by lead and oxygen atoms. These fragments are connected by alkoholate molecules. In 5 additionally an I₆ octahedra centered by lead is observed.     

Dissociative photoionization of isoprene: experiments and calculations

Vacuum ultraviolet (VUV) dissociative photoionization of isoprene in the energy region 8.5–18 eV was investigated with photoionization mass spectroscopy (PIMS) using synchrotron radiation (SR). The ionization energy (IE) of isoprene as well as the appearance energies (AEs) of its fragment ions C₅H₇⁺, C₅H₅⁺, C₄H₅⁺, C₃H₆⁺, C₃H₅⁺, C₃H₄⁺, C₃H₃⁺ and C₂H₃⁺ were determined with photoionization efficiency (PIE) curves. The dissociation energies of some possible dissociation channels to produce those fragment ions were also determined experimentally. The total energies of C₅H₈ and its main fragments were calculated using the Gaussian 03 program and the Gaussian‐2 method. The IE of C₅H₈, the AEs for its fragment ions, and the dissociation energies to produce them were predicted using the high‐accuracy energy model. According to our results, the experimental dissociation energies were in reasonable agreement with the calculated values of the proposed photodissociation channels of C₅H₈. Copyright © 2009 John Wiley & Sons, Ltd.     

Infrared chemiluminescence in the reactions of atomic fluorine with ethanol,propanol-(2) and some deuterated analogs

In the reactive systems F+C₂H₅OH, F+C₂D₅OD, F+C₂H₅OD, F+(CH₃)₂CHOH, F+(CD₃)₂CHOH, and F+(CD₃)₂CDOH the infrared emission spectra were recorded from HF and/or DF in the fundamental region. Hydrogen abstraction takes place from CH and OH bonds. Vibrational relaxation was suppressed and rotational relaxation took place only to a minor extent. HF(DF) excitation reaches the thermodynamic limit within error limits in all cases. The vibrational distributions of HF for the systems F+(CD₃)₂CHOH, F+(CD₃)₂CDOH show no populati inversion. The vibrational distribution of HF for all other systems and all the DF vibrational distributions obtained show population inversion. Inform theory was used to describe the results of those reaction channels that could be studied separately because of isotopic substitution. The results are c to the systems F + methanol and deuterated analogs investigated before in our laboratory, and to the F+CH₄, F+CD₄, and F+H₂O₂ reactio     

Charge Fluctuations and Ethylene‐Group‐Ordering Transition in β′′‐(BEDT‐TTF)4[(H3O)Fe(C2O4)3]⋅Y Molecular Charge‐Transfer Salts

The polarized infrared reflectance and Raman spectra of the three quasi‐two‐dimensional β′′‐(BEDT‐TTF)₄[(H₃O)Fe(C₂O₄)₃]?Y bifunctional charge‐transfer salts, where BEDT‐TTF=bis(ethylenedithio)tetrathiafulvalene and Y=C₆H₅Br, (C₆H₅CN)_0.17(C₆H₅Br)_0.83, (C₆H₅CN)_0.4(C₆H₅F)_0.6, have been measured as a function of the temperature. Signatures of charge inhomogenity have been found in both Raman and infrared spectra of the β′′‐(BEDT‐TTF)₄[(H₃O)Fe(C₂O₄)₃]?Y superconductors. A 100 K transition to a mixed insulating/metallic state is clearly seen for the first time in the temperature dependence of the electronic spectra of superconducting β′′‐(BEDT‐TTF)₄[(H₃O)Fe(C₂O₄)₃]?C₆H₅Br. We suggest that this phase transition is due to subtle changes in the ethylene groups ordering, which are related to a structural phase transition in the anionic layer. The infrared and Raman spectra of quasi‐two‐dimensional metal α‐′pseudo‐κ′‐(BEDT‐TTF)₄[(H₃O)Fe(C₂O₄)₃]C₆H₄Br₂ are also investigated.     

Syntheses and Spectroscopic Study of Some New N‐4‐Fluorobenzoyl Phosphoric Triamides; Crystal Structures of 4‐F‐C6H4C(O)N(H)P(O)R2, R = NH‐C(CH3)3, NH‐CH2C6H5, N(CH3)(CH2C6H5)

Some new N‐4‐Fluorobenzoyl phosphoric triamides with formula 4‐F‐C₆H₄C(O)N(H)P(O)X₂, X = NH‐C(CH₃)₃ ( 1 ), NH‐CH₂‐CH=CH₂ ( 2 ), NH‐CH₂C₆H₅ ( 3 ), N(CH₃)(C₆H₅) ( 4 ), NH‐CH(CH₃)(C₆H₅) ( 5 ) were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR and Mass spectroscopy and elemental analysis. The structures of compounds 1 , 3 and 4 were investigated by X‐ray crystallography. The P=O and C=O bonds in these compounds are anti. Compounds 1 and 3 form one dimensional polymeric chain produced by intra‐ and intermolecular ‐P=O···H‐N‐ hydrogen bonds. Compound 4 forms only a centrosymmetric dimer in the crystalline lattice via two equal ‐P=O···H‐N‐ hydrogen bonds. ¹H and ¹³C NMR spectra show two series of signals for the two amine groups in compound 1 . This is also observed for the two α‐methylbenzylamine groups in 5 due to the presence of chiral carbon atom in molecule. ¹³C NMR spectrum of compound 4 shows that ²J(P,C_aliphatic) coupling constant for CH₂ group is greater than for CH₃ in agreement with our previous study. Mass spectra of compounds 1 ‐ 3 (containing 4‐F‐C₆H₄C(O)N(H)P(O) moiety) indicate the fragments of amidophosphoric acid and 4‐F‐C₆H₄CN⁺ that formed in a pseudo McLafferty rearrangement pathway. Also, the fragments of aliphatic amines have high intensity in mass spectra.     

Synthesis,molecular and electronic structures of half-sandwich ruthenium(II) complexes with pyrimidine-based ligands

The complexes [(C₆H₆)RuCl₂(Hmtp)] and [(C₆H₆)RuCl₂(C₄H₄N₂)] have been prepared and studied by IR, ¹H NMR, UV–VIS spectroscopy and X-ray crystallography. The complexes were prepared by reactions of [(C₆H₆)RuCl₂]₂ with 7-hydroxy-5-methyl[1,2,4]triazolo[1,5-a]pyrimidine (Hmtp) and pyrimidine, respectively, in methanol. The electronic structures and UV–Vis spectra of the complexes have been calculated using the TD–DFT method.     

Synthesis,crystal structure,photoluminescence properties of organic-inorganic hybrid materials based on ethylenediamine bromide

In this work, a new orthorhombic organic-inorganic hybrid single crystal (C₂H₁₀N₂)₂MnBr₄.2Br with-Zero-dimensional structure was synthesized by slow evaporation method at 75 °C. The crystal structure and intermolecular interactions were performed by single crystal X-ray diffraction and Hirshfeld surface. Optical properties of (C₂H₁₀N₂)₂MnBr₄.2Br were systematically studied by Raman, infrared spectrum, UV–vis, photoexcitation spectra, and photoluminescence spectra. The optical band gap (E_g = 2.61 eV) were calculated from the absorption spectra of (C₂H₁₀N₂)₂MnBr₄.2Br. This hybrid materials also had shown good thermal stability (decomposition temperature: 288–660 °C). Finally, photoluminescence measurements showed a strong excitation line at 362 nm and a strong fluorescence at 537 nm which makes it a promising material in luminescence field.     

Spin-orbit ab initio investigation of the photodissociation of C2H5Br

The photodissociation of ethyl bromide (C₂H₅Br) has been investigated by spin-orbit (SO) ab initio calculations. The vertical excitation energies of some excited states for C₂H₅Br were calculated. The potential energy curves of C₂H₅Br along the C–Br dissociation coordinate were calculated by multistate second-order multiconfigurational perturbation theory in conjunction with spin-orbit (SO) interaction through complete active space state interaction (MS-CASPT2/CASSI-SO). The calculated results clearly assigned the experimentally observed photodissociation channels leading to C₂H₅ + Br (²P_3/2) and C₂H₅ + Br*(²P_1/2).     

Synthesis,characterization, crystal structure,and electrochemical property of copper(II) complexes with Schiff bases derived from 5-halogenated salicylaldehyde and amantadine

A mixture of copper(II) chloride dihydrate and ligands derived from amantadine and 5-halogenated salicylaldehyde in anhydrous methanol generated two novel complexes C₃₄H₃₈Cl₂CuN₂O₂ (I) and C₃₄H₃₈Br₂CuN₂O₂ (II), respectively. The complexes were characterized by melting point, elemental analysis, molar conductance, IR, UV-Vis, and single-crystal X-ray diffraction (CIF files nos. 1435429 (I), 1435430 (II)). Single-crystal X-ray diffraction analysis reveals that both complexes crystallize in monoclinic system, P2₁/c space group. Each asymmetric unit consists of two mononuclear copper(II) complex molecules and each complex molecule includes one copper(II) atom two corresponding deprotonated ligands. The central copper(II) atom is four-coordinated via two nitrogen atoms and two oxygen atoms from the corresponding Schiff base ligands, forming a distorted tetrahedral geometry. Electrochemical properties of the complexes were studied by cyclic voltammetry.     

Synthesis, molecular, crystal and electronic structure of [(C6H6)RuCl(1,10-C12H8N2)]Cl

The [(C₆H₆)RuCl(1,10-C₁₂H₈N₂)]Cl complex has been prepared and studied by IR, UV-Vis, ¹H NMR spectroscopy and X-ray crystallography. The complex was prepared in reaction of [(C₆H₆)RuCl₂]₂ with 1,10-phenatroline in acetone. The electronic spectrum of the compound has been calculated using the TDDFT method.     

Study of substituent effects on rotational isomers and monomer–dimer equilibria of the 3-carboxy group in 4-substituted (R)-2-(3,4-methylenedioxyphenyl)-6-isopropyloxy-2H-chromen-3-carboxylic acids in dilute CCl4 and CHCl3 solutions by FTIR spectroscopy

FTIR spectra of the title carboxylic acids (I–III) with 4-substituents (H, CH₃ or C₆H₅) and their related compounds IV–VI with 4-(substituted phenyl) groups were measured in dilute CCl₄ and CHCl₃ solutions. The concentration dependence of FTIR spectra of I–IV was also measured in these solutions. These spectra were subjected to curve analysis in order to quantitatively identify the rotational isomers of 3-carboxy group attributable to steric hindrance of the 4-substituents. For I, II and III–VI, two, four and five ν(CO) bands were observed for their carboxy groups, respectively, indicative of monomer–dimer equilibrium and two and three kinds of rotational isomers for II and III–VI, respectively. Compounds III–VI were found to form intra-molecular hydrogen bonds between the trans-type of the 3-carboxy group and the π-electrons in the 4-benzene ring. We have worked out a method to estimate the association constant (K) of complicated monomer–dimer equilibria such as II–VI. The K values of I–IV decrease remarkably in the order of H (I), C₆H₅ (III), CH₃ (II) and C₆H₄-p-OCH₃ (IV) in CCl₄ and I, II, III and IV in CHCl₃; these orders are discussed.