Intersystem Crossing and Electron Spin Selectivity in Anthracene-Naphthalimide Compact Electron Donor-Acceptor Dyads Showing Different Geometry and Electronic Coupling Magnitudes

Anthracene-naphthalimide (An-NI) compact electron donor-acceptor dyads were prepared, in which the orientation and distance between the two subunits were varied by direct connection or with intervening phenyl linker. Efficient intersystem crossing (ISC) and long triplet state lifetime (Φ_Δ=92 %, τ_T=438 μs) were observed for the directly connected dyads showing a perpendicular geometry (81°). This efficient spin-orbit charge transfer ISC (SOCT-ISC) takes 376 fs, inhibits the direct charge recombination (CR) to ground state (¹CT→S₀, takes 3.04 ns). Interestingly, efficient SOCT-ISC for dyads with intervening phenyl linker (Φ_Δ=40 % in DCM) was also observed, although the electron donor and acceptor adopt almost coplanar geometry (dihedral angle: 15°). Time-resolved electron paramagnetic resonance (TREPR) spectroscopy shows that the electron spin polarization of the triplet state, i. e. the electron spin selectivity of ISC, is highly dependent on the dihedral angle and the linker. For the dyads showing weaker coupling between the donor and acceptors, the charge separation and the intramolecular triplet energy transfer are inhibited at 80 K (frozen solution), because both the ³An and ³NI states were observed and the ESP are same as compared to the native anthracene and naphthalimide, which unravel their origin. The dyads were used as triplet photosensitizers for triplet−triplet annihilation upconversion (TTA UC). High UC quantum yield (Φ_UC=12.9 %) as well as a large anti-Stokes shift (0.72 eV) was attained by excitation into the CT absorption band.     

Direct synthesis of tetrazine functionalities on polymer backbones

Tetrazine mediated inverse Electron Demand Diels–Alder Reaction (IEDDA) is an important modification technique due to its high selectivity and super‐fast kinetics. Incorporation of tetrazine moieties on polymer chains requires multistep synthetic pathways and a post‐polymerization step leading to functional polymeric materials. Such approaches involve separate syntheses of polymer and the molecule which will be employed in modification. Herein, we introduce a straightforward synthetic approach for direct synthesis of tetrazine groups on polymers as side chains. As model systems, tetrazine functional poly(N‐isopropylacrylamide)‐and poly(ethylene glycol)‐based polymers from corresponding precursor polymers with nitrile moieties as pendant groups are prepared and IEDDA Click Reaction is achieved with trans‐cyclooctene derivatives. The click reaction is monitored by both NMR and UV–vis spectroscopies. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019 , 57, 673–680     

A Spring-Layer Model for a Bi-Layered Plate-Strip with Initial Stress Through Imperfect Contact Interface

In this paper, we present our report on the forced vibration of a bi-layered plate-strip with initial stress resting on a rigid foundation induced by a time-harmonic force. The investigation is carried out according to the piecewise homogeneous body model with utilizing the three-dimensional linearized theory of elastic waves in initially stressed bodies (TLTEWISB). The materials of the body are chosen to be linearly elastic, homogeneous, and isotropic. The interface between the layers is assumed to be imperfect, and is simulated by the spring-layer model. A similar degree of imperfection on the interface is realized in the normal and tangential directions. The mathematical model for the problem under consideration is designed, and the system of the equations of motion is approximately solved by employing the finite element method (FEM). The numerical results explaining the influence of the parameter that characterizes the degree of corresponding imperfectness on the dynamic response of the plate-strip are presented. In particular, we demonstrate that the distributions of the normal stress become flat, as the normal-spring parameter increases.     

Supply chain contracts for capacity decisions under symmetric and asymmetric information

Central European Journal of Operations Research - Production capacity decision under random demand is an important factor that significantly effects supply chain profits. It is realized in...     

A Diverse‐Stimuli Responsive Chemiluminescent Probe with Luminol Scaffold and Its Electropolymerization

A diverse‐stimuli responsive chemiluminescent system, SNS‐Lum, and its electropolymerization to give PSNS‐Lum, which is the first example of conjugated polymers with pendant luminol arms inducing chemiluminescence in the presence of super oxide radical anion under neutral conditions, are highlighted.     

Synthesis,characterization, thermal stability,conductivity, and band gaps of substitute oligo/polyamines or polyphenol

In this study, the oxidative polycondensation reaction conditions of 3,5‐dichloroaniline (DCA), 3,4,5‐trimethoxyaniline (TMA), 3,5‐bis(trifluoromethyl)aniline (BTFMA), and 4‐{[(3,5‐dichlorophenyl)imino]methyl}phenol (DCPIMP) were studied by using NaOCl oxidant in an aqueous alkaline medium between 40 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FT‐IR, Ultraviolet–visible (UV–vis), ¹H‐NMR, and ¹³C‐NMR and elemental analysis. The characterization was made by TGA–DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yields of oligo‐3,5‐dichloroaniline (ODCA), poly‐3,4,5‐trimethoxy aniline (PTMA), oligo‐3,5‐bis(trifluoromethyl)aniline (OBTFMA), and poly‐4‐{[(3,5‐dichlorophenyl) imino]methyl} phenol (PDCPIMP) were found to be 98, 48, 80, and 83% in using NaOCl oxidant. According to the SEC analysis, the number‐average molecular weight (M_n), weight‐average molecular weight (M_w) and polydispersity index (PDI) values of ODCA, PTMA, and OBTFMA were found to be 2200, 3800 g mol^?1, and 1.727; 4700, 7500 g mol^?1, and 1.596; and 1690, 1950 g mol^?1, and 1.154, respectively. According to TG analysis, the weight losses of ODCA, PTMA, OBTFMA, and PDCPIMP were found to be 78.55, 54.18, 99.38, and 59.70% at 1000°C, respectively. PTMA showed higher stability against thermal decomposition. Electrical conductivity of the polymers was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital (HOMO), the lowest unoccupied molecular orbital (LUMO) and electrochemical band gaps ( ) of ODCA, PTMA, OBTFMA, and PDCPIMP were calculated from their absorption edges of cyclic voltammograms. The optical band gaps (E_g) values of all compounds were calculated from UV–vis measurements. Copyright © 2009 John Wiley & Sons, Ltd.     

Chemical composition of natural colophony from Pinus brutia and comparison with synthetic colophony

The compositions of colophony resins obtained from Pinus brutia Ten trees by three different methods (acid paste, carved hole and scraping) from Ayvacik, G?kova and Kemalpa?a in Turkey were analyzed by capillary GC-MS. The main components were the monoterpenes alpha-pinene, beta-pinene, and delta3-carene, and the diterpenic resin acids palustric, abietic, kaur-9(11)-16-en-18-oic and neoabietic acid. The synthetic colophony resins exhibited similar contents to those of the natural resins obtained from the G?kova and Kemalpa?a regions of Turkey. However, colophony resins from Ayvacik exhibited only half the diterpenic acid content as those of the G?kova and Kemalpa?a resins. Out of the three techniques, the carved hole method caused rather different percentages in the constituents of the essential oils.     

Novel Polymer Monolithic Column for Hydrophilic Compounds

A hydrophilic polymer-based monolithic column was prepared from water-soluble crosslinking agents for liquid chromatography. The column media were prepared with a diacrylate monomer, aqueous polyethylene glycol, methanol, and a water-soluble radical initiator. A fused silica capillary column, which was significantly modified by vinyl groups, was utilized as the outer column in order to control polymer shrinkage. We optimized the modification of the capillary column, composition of the monomer and porogen, and polymerization condition. The optimized column exhibited high hydrophilicity and achieved the baseline separation of nucleobases by using only a buffered solution as the mobile phase. Additionally, another column prepared from binary water-soluble crosslinking agents exhibited lower nonspecific adsorption of several proteins. Basically, we would show the possibility of a new type of polymer monolith prepared from water-soluble crosslinker and water-soluble porogenic solvent, and they can be used for chromatographic separation without non-specific hydrophobic interaction.     

Quantitative evaluations of surface-concentrated amino groups on monolithic-type solid supports prepared by copolymerization method

We have prepared novel monolithic-type highly cross-linked solid supports having surface amino group using a copolymerization method of functional monomers and cross-linking monomer. From the view point of controlled surface functionalities, we have firstly certified and proved quantitative determination methods of the surface amino groups to utilize and evaluate those solid supports prepared as affinity resins. We utilized a typical titration method and ninhydrin method that have been effectively utilized for quantitative determination of primary amine and amino acid. The ninhydrin method was calibrated using octylamine as a standard compound (R ² = 0.998) and proved applicability for the quantitative determination of other primary amines. A commercially available solid support, Affigel, was able to be quantitatively evaluated only by the ninhydrin method, while Toyopearl afforded just compatible amino group density to the value certified by the manufacturer only through titration method. The obtained incompatible results using both determination methods have been unclear at this moment. On the other hand, both determination methods afforded compatible amino group density of the prepared solid support. The obtained value was up to 126 μmol/ml, which was 94% of the calculated theoretical value based on the feed composition. The results suggested surface-concentrated introduction of amino groups. Based on the determination methods, especially ninhydrin method, we prepared the monolithic-type solid supports having various densities of surface amino groups and proved quantitative and surface-concentrated introduction of amino groups. Those amino groups were able to react with a relatively large ligand molecule, methotrexate, quantitatively and also with controlled density. The obtained results strongly suggest that the novel monolithic-type solid supports have possible advantages when we utilize those as affinity resins for target peptide analyses.     

Exact solutions of nonlinear evolution equations with variable coefficients using exp-function method

In this paper, we apply the exp-function method to construct generalized solitary and periodic solutions of nonlinear evolution equations with variable coefficients. The proposed technique is tested on the Zakharov-Kuznetsov and (2+1)-dimensional Broer-Kaup equations with variable coefficients. These equations play a very important role in mathematical physics and engineering sciences. The suggested algorithm is quite efficient and is practically well suited for use in these problems. Obtained results clearly indicate the reliability and efficiency of the proposed exp-function method.