Time-dependent density functional theory study of the spectroscopic properties related to aggregation in the platinum(II) biphenyl dicarbonyl complex

Singlet ground-state geometry optimization of the monomer, four dimers, and the trimer of [Pt(bph)(CO)(2)], where bph = biphenyl dianion, was performed at the B3LYP level of density functional theory (DFT) with a mixed basis set (6-311G** on C, O, and H atoms; the Stuttgart/Dresden (SDD) effective core potential (ECP) on the Pt core; [6s5p3d] on the Pt valence shell). The aggregation was based on Pt[bond]Pt binding as well as on pi[bond]pi and electrostatic interactions. The lowest-lying triplet-state geometries of the monomer, one dimer, and the trimer of the complex were also optimized using the above theory. Significant shortening of the Pt[bond]Pt bond was recorded in the triplet state compared to the singlet one. A number of low-energy singlet and triplet allowed excited states were calculated using time-dependent density functional theory (TDDFT) and analyzed with respect to absorption, excitation, and emission spectra collected under various conditions. Simulated spectra of the monomer and dimer based on the singlet excited states were correlated with the absorption spectrum. The emission in concentrated solution was due to the triplet dimer, and the emitting states were (3)MLCT and Pt-centered states.     

Composition and structure of zirconium complexes in tributyl phosphate extracts of Zr from concentrated nitric acid solutions

Using quantitative difference IR spectroscopy we have found that the tibutyl phosphate & acts of zirconium from 12–15 M HN03 contain ionic associates [(TBP)₂H⁺]Zr(NO₃)₅ ^– (I) and [TBP· H₃0⁺ (H₂0)_n]Zr(N0₃)₅ ^– (II), where n = 1, 2, as well as the Zr(N0₃)₄(TBP)₂ complex at a lower concentration than (I) and (I.). The equilibrium I II is shifted toward II at higher C_{HNo 3} ⁰ and lower c_Zr ⁰. The structure of associates I and II is discussed.Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, D. I. Mendeleev Moscow Chemical Technological Institute. Translated fromZhurnal Strukturnoi Khimii, Vol. 34, No. 5, pp. 80–89, September–October, 1993.Translated by L. Smolina     

The correspondence of detachment characteristics and acid-base interaction measures

A quantitative estimate for the intensity of interphase acid-base interactions is proposed based on the acid and base parameters of the free surface energy of polymer adhesives and substrates of a different nature. An interaction between acid-base and strength characteristics of adhesive compounds is established. An increase in the adhesive strength with an increase in the difference between the surface acid and base properties of connected materials is revealed for a number of compounds (polyolefine-metal, rubber mixtures-brass, and Thiokol compounds-glass).     

Density functional theory investigation of the binding interactions between phosphoryl,carbonyl, imino,and thiocarbonyl ligands and the pentaaqua nickel(II) complex: Coordination affinity and associated parameters

Density Functional Theory (UB3LYP/6‐311++G(d,p)) calculations of the affinity of the pentaaqua nickel(II) complex for a set of phosphoryl [O?P(H)(CH₃)(PhR)], imino [HN?C(CH₃)(PhR)], thiocarbonyl [S?C(CH₃)(PhR)] and carbonyl [O?C(CH₃)(PhR)] ligands were performed, where R?NH₂, OCH₃, OH, CH₃, H, Cl, CN, and NO₂ is a substituent at the para‐position of a phenyl ring.The affinity of the pentaaqua nickel(II) complex for these ligands was analized and quantified in terms of interaction enthalpy (ΔH), Gibbs free energy (ΔG²⁹⁸), geometric and electronic parameters of the resultant octahedral complexes. The ΔH and ΔG²⁹⁸ results show that the ligand coordination strength increases in the following order: carbonyl < thiocarbonyl < imino < phosphoryl. This coordination strength order is also observed in the analysis of the metal‐ligand distances and charges on the ligand atom that interacts with the Ni(II) cation. The electronic character of the substituent R is the main parameter that affects the strength of the metal‐ligand coordination. Ligands containing electron‐donating groups (NH₂, OCH₃, OH) have more exothermic ΔH and ΔG²⁹⁸ than ligands with electron‐withdrawing groups (Cl, CN, NO₂). The metal‐ligand interaction decomposed by means of the energy decomposition analysis (EDA) method shows that the electronic character of the ligand modulates all the components of the metal‐ligand interaction. The absolute softness of the free ligands is correlated with the covalent contribution to the instantaneous interaction energy calculated using the EDA method. © 2013 Wiley Periodicals, Inc.     

Properties of wood-polymer composites with a polymer matrix containing sevilens

The effect of vinylacetate unit content in sevilen used as a polymer matrix or polyethylene compatibilizer on the properties of wood-polymer composites with a thermoplastic binders and filler of plant origin is studied. It is shown that the introduction of vinylacetate units decreases the tensile strength, contact elastic modulus, Brinell hardness, and water absorption of the composites, but increases the relative tensile elongation and impact viscosity without notch.     

Influence of colloidal structure of polymer mixes on adhesion strength of polyolefin compositions

Mixtures of low-density polyethylene and ethylene-vinyl acetate (EVA) copolymer are studied. It is shown that the adhesion value is defined by the polymer that forms a dispersion medium in the adhesive compositions and the type of fracture depends on the competing influence of the physical and mechanical parameters and the reduced acidity parameter of the polymer, which forms a continuous phase.     

Electrical and electroluminescent properties of InAsSb-Based LEDs (λ = 3.85–3.95 μm) in the temperature interval 20–200°C

The temperature dependences of the electrical and electroluminescent properties of InAsSbP/InAsSb/InAsSbP heterostructure LEDs (λ ≈ 3.8−4.0 μm) are studied in the temperature interval 20–200°C. It is shown that the radiation power decreases with increasing temperature in a superexponential manner and that this decrease is associated primarily with a rise in the rate of Auger recombination. The position of the maximum in the radiation spectrum varies with temperature nonmonotonically, since radiative recombination is observed both in the active region and in the wide-gap layer. At room temperature, current through the heterostructure is tunneling current irrespective of the applied voltage polarity. As the temperature rises, either the thermal emission of charge carriers appears (direct bias) or the diffusion current becomes significant (reverse bias).     

A magnetostatic-coupling based remote query sensor for environmental monitoring

A new type of in situ, remotely monitored magnetism-based sensor is presented that is comprised of an array of magnetically soft, magnetostatically-coupled ferromagnetic thin-film elements or particles combined with a chemically responsive material that swells or shrinks in response to the analyte of interest. As the chemically responsive material changes size the distance between the ferromagnetic elements changes, altering the inter-element magnetostatic coupling. This in turn changes the coercive force of the sensor, the amplitude of the voltage spikes detected in nearby pick-up coils upon magnetization reversal and the number of higher-order harmonics generated by the flux reversal. Since the sensor is monitored through changes in magnetic flux, no physical connections such as wires or cables are needed to obtain sensor information, nor is line of sight alignment required as with laser telemetry; the sensors can be detected from within sealed, opaque or thin metallic enclosures.     

On the free scalar massless field in two-dimensional space-time

In the present paper the solutions of the quantum field problem for the free scalar massless field in two-dimensional space time are constructed. It is shown that the fields obtained cannot vanish at space-like infinity. The latter fact implies the existence of two conserved charge operators. The transformation properties of these solutions under the two-dimensional Lorentz group are examined.