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51.
Yu Dong Dr. Ayhan Elmali Prof. Jianzhang Zhao Prof. Bernhard Dick Dr. Ahmet Karatay 《Chemphyschem》2020,21(13):1388-1401
Orthogonal phenoxazine-styryl BODIPY compact electron donor/acceptor dyads were prepared as heavy atom-free triplet photosensitizers (PSs) with strong red light absorption (ϵ=1.33×105 M−1 cm−1 at 630 nm), whereas the previously reported triplet photosensitizers based on the spin-orbit charge transfer intersystem crossing (SOCT-ISC) mechanism show absorption in a shorter wavelength range (<500 nm). More importantly, a long-lived triplet state (τT=333 μs) was observed for the new dyads. In comparison, the triplet state lifetime of the same chromophore accessed with the conventional heavy atom effect (HAE) is much shorter (τT=1.8 μs). Long triplet state lifetime is beneficial to enhance electron or energy transfer, the primary photophysical processes in the application of triplet PSs. Our approach is based on SOCT-ISC, without invoking of the HAE, which may shorten the triplet state lifetime. We used bisstyrylBodipy both as the electron acceptor and the visible light-harvesting chromophore, which shows red-light absorption. Femtosecond transient absorption spectra indicated the charge separation (109 ps) and SOCT-ISC (charge recombination, CR; 2.3 ns) for BDP-1 . ISC efficiency of BDP-1 was determined as ΦT=25 % (in toluene). The dyad BDP-3 was used as triplet PS for triplet-triplet annihilation upconversion (upconversion quantum yield ΦUC=1.5 %; anti-Stokes shift is 5900 cm−1). 相似文献
52.
Cemil Aydoan Bekir elebi Aslhan Bayraktar Fatma Ylmaz Adil Denizli Ali Tuncel 《先进技术聚合物》2014,25(8):777-783
A new reactive monolith, poly(3‐chloro‐2‐hydroxypropyl methacrylate‐co‐ethylene dimethacrylate), poly(HPMA‐Cl‐co‐EDMA) was synthesized and post‐functionalized by taurine (2‐aminoethane sulfonic acid) to obtain a zwitterionic stationary phase for capillary electrochromatography. The new stationary phase contained charged groups such as secondary amine providing anodic electroosmotic flow and sulfonic acid groups providing cathodic electroosmotic flow. Hence, the capillary electrochromatography separations with the new zwitterionic monolith were performed with either anodic or cathodic electroosmotic flow. The electrochromatographic separation of alkylbenzenes and phenols was successfully performed. The zwitterionic monolith also allowed the separation of nucleosides using only electrokinetic mode. Theoretical plate numbers up to ~105 plates/m were achieved. Our study is the first report based on poly(HPMA‐Cl‐co‐EDMA) reactive monolith post‐functionalized with a zwitterionic ligand allowing to operate in both anodic and cathodic electroosmotic flow modes. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
53.
We characterize for modules consisting of tuples of Laurent polynomials with real coefficients whether such a module contains a positive element. The two conditions needed are numerical and directional positivity. The proof applies universal Gröbner bases. 相似文献
54.
55.
M. Yatin S. G. Tuncel G. Tuncel N. K. Aras 《Journal of Radioanalytical and Nuclear Chemistry》1990,140(2):315-321
Characterization of dilute solution of gamma-irradiated polymethyl methacrylate (PMMA) in acetone has been carried out. The polymer sample in form of natural beads was administered a gamma-ray dose of 30 kGy by a cobalt-60 radiationsource. Various types of viscosities, viscosity average molecular weight, shape and size of irradiated PMMA and its two fractions were calculated. The results were compared with those for unirradiated PMMA. Degradation of PMMA as a result of irradiation has been observed. 相似文献
56.
Positive matrix factorization (PMF) was used to deduce the aerosol sources at a rural site on the Mediterranean coast of Turkey, using sample collected between February 1992 and December 1993. Approximately 600 daily aerosol samples were collected and 40 elements and compounds were analyzed by atomic absorption spectrometry, instrumental neutron activation analysis, ion chromatography and colorimetry.Seven factors were identified with PMF, namely local dust, Saharan dust, sea salt, long range transport, smelter, arsenic and fertilizer factors. The non-parametric bootstrapped potential source contribution function (PSCF) was then used to help identify likely locations of the regional sources of pollution. Besides, explained variance, enrichment factors, seasonal variation of G-score values and back trajectories were used to define the source regions of the factors. Results demonstrated that there are major potential source areas, for the pollution-derived component in aerosol mass, on the Aegean coast, Northwest Turkey, Balkan countries, Ukraine and regions located northern part of Ukraine. 相似文献
57.
The quaternary indides LaTIn3Mg (T = Rh and Ir) and CeIrIn3Mg were prepared from the elements in sealed tantalum ampoules in an induction furnace. The samples were characterized by X-ray powder and single crystal data: LaCoAl4 type, Pmma, Z = 2, a = 830.5(1), b = 436.1(1), c = 745.1(1) pm, wR2 = 0.038, 467 F 2 values for LaRhIn3.075Mg0.925, a = 832.9(1), b = 436.5(1), c = 746.9(1) pm, wR2 = 0.077, 471 F 2 values for LaIrIn3.091Mg0.909, and a = 832.2(1), b = 434.1(1), c = 743.9(1) pm, wR2 = 0.066, 465 F 2 values for CeIrIn3.07Mg0.93 with 25 variables for each refinement. The transition metal, indium, and magnesium atoms build up three-dimensional [TIn3Mg] networks which leave pentagonal prismatic voids for the lanthanum and cerium atoms. The transition metal atoms have tricapped trigonal prismatic coordination and the magnesium atoms fill distorted square prisms. All three crystals revealed a small degree of Mg/In mixing on the latter site. 相似文献
58.
Ceyhan T Yüksek M Yağlioğlu HG Salih B Erbil MK Elmali A Bekaroğlu O 《Dalton transactions (Cambridge, England : 2003)》2008,(18):2407-2413
In this study, the preparation of some novel metallophthalocyanine (MPcs) complexes substituted with octakis(mercaptopropylisobutyl-POSS) functional group was achieved. By the reaction of [1-(3-mercapto)propyl-3,5,7,9,11,13,15-isobutylpentacyclo[9.5.1.1(3,9).1(5,15).1(7,13)]octasiloxane 1 with 4,5-dichloro-1,2-dicyanobenzene 2 in THF as the solvent in the presence of K2CO3 as the base, the phthalonitrile derivative 3 was synthesized. Compound 3 reacted with CoCl2 x 6H2O in ethylene glycol to furnish a novel cobalt(II) phthalocyanine . The tetramerization of 3 with urea and CuCl in the absence of solvent gave the novel Cu(II) phthalocyanine 4; while with Zn(OAc)2 x 2H2O in dry DMF gave the novel zinc(ii) phthalocyanine 6. The structures of the target compounds were confirmed by elemental analysis, UV/VIS, IR, MALDI-TOF MS and 1H NMR spectra. Nonlinear absorptions of MPcs in chloroform solution were investigated by using Z-scan measurement technique with 4 ns pulses at 532 nm wavelength. While CuPc 5 showed very high nonlinear absorption, MPcs 4 and 6 did not show considerable nonlinear absorption. Investigations of optical limiting properties of 5 revealed that this material is a very good candidate for optical limiting applications. 相似文献
59.
Dr. Elif Akhuseyin Yildiz Dr. Ebru Yabaş Prof. Fazlı Sözmen Dr. Yasemin Bozkurt Dr. Ahmet Karatay Prof. Bahadir Boyacioglu Prof. Hüseyin Ünver Dr. Ayhan Elmali 《Chemphyschem》2023,24(5):e202200735
Borondipyrromethene (BODIPY) chromophores are composed of a functional-COOH group at meso position with or without a biphenyl ring, and their compounds with heavy iodine atoms at −2, −6 positions of the BODIPY indacene core were synthesized. The photophysical properties of the compounds were studied with steady-state absorption and fluorescence measurements. It was observed that the absorption band is significantly red-shifted, and fluorescence signals are quenched in the presence of iodine atoms. In addition to that, it was indicated that the biphenyl ring does not affect the spectral shifting in the absorption as well as fluorescence spectra. In an attempt to investigate the effect of π-expanded biphenyl moieties and heavy iodine atoms on charge transfer dynamics, femtosecond transient absorption spectroscopy measurements were carried out in the environment of the tetrahydrofuran (THF) solution. Based on the performed ultrafast pump-probe spectroscopy, BODIPY compounds with iodine atoms lead to intersystem crossing (ISC) and ISC rates were determined as 150 ps and 180 ps for iodine BODIPY compounds with and without π-expanded biphenyl moieties, respectively. According to the theoretical results, the charge transfer in the investigated compounds mostly appears to be intrinsic local excitations, corresponding to high photoluminescence efficiency. These experimental findings are useful for the design and study of the fundamental photochemistry of organic triplet photosensitizers. 相似文献
60.
Selcan Tuncel Rolf‐Dieter Hoffmann Bernard Chevalier Dr. Samir F. Matar Dr. Rainer Pöttgen Prof. Dr. 《无机化学与普通化学杂志》2007,633(1):151-157
The new rare earth metal rich intermetallic compounds RE4CoMg (RE = Y, La, Pr, Nd, Sm, Gd–Tm) were prepared via melting of the elements in sealed tantalum tubes in a water‐cooled sample chamber of a high‐frequency furnace. The compounds were investigated by X‐ray diffraction of powders and single crystals: Gd4RhIn type, , a = 1428.38(9) pm, wR2 = 0.0638, 680 F2 values, 20 variables for La4CoMg, a = 1399.5(2) pm, wR2 = 0.0584, 589 F2 values, 20 variables for Pr4CoMg, a = 1390.2(3) pm, wR2 = 0.0513, 634 F2 values, 20 variables for Nd3.90CoMg1.10, a = 1381.0(3) pm, wR2 = 0.0730, 618 F2 values, 22 variables for Sm3.92Co0.93Mg1.08, a = 1373.1(4) pm, wR2 = 0.0586, 611 F2 values, 20 variables for Gd3.92CoMg1.08, a = 1362.1(3) pm, wR2 = 0.0576, 590 F2 values, 20 variables for Tb3.77CoMg1.23, a = 1344.8(2) pm, wR2 = 0.0683, 511 F2 values, 20 variables for Dy3.27CoMg1.73, and a = 1343.3(2) pm, wR2 = 0.0560, 542 F2 values, 20 variables for Er3.72CoMg1.28. The cobalt atoms have trigonal prismatic rare earth coordination. Condensation of the CoRE6 prisms leads to a three‐dimensional network which leaves larger voids that are filled by regular Mg4 tetrahedra at a Mg–Mg distance of 316 pm in La4CoMg. The magnesium atoms have twelve nearest neighbors (3 Mg + 9 RE) in icosahedral coordination. In the structures with Nd, Sm, Gd, Tb, Dy, and Er, the RE1 positions which are not involved in the trigonal prismatic network reveal some RE1/Mg mixing and the Sm3.92Co0.93Mg1.08 structure shows small cobalt defects. Considering La4CoMg as representative of all studied systems an analysis of the chemical bonding within density functional theory closely reproduces the crystal chemistry scheme and shows the role played by the valence states of the different constituents in the electronic band structure. Strong bonding interactions were observed between the lanthanum and cobalt atoms within the trigonal prismatic network. 相似文献