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101.
Yavuz Ergun 《Journal of heterocyclic chemistry》2007,44(3):539-541
A short synthesis of the hexahydropyrido[4,3‐b]carbazole derivative 8 which is important for the preparation of aspidosperma alkaloids was described. Construction of the tetracyclic structure was achieved via a short synthetic route and some new carbazolone derivatives ( 4, 5, 6 and 7 ) were synthesized. 相似文献
102.
103.
The Schiff base compound 2-[(4-propylphenylimino)methyl]-4-nitrophenol has been synthesized and characterized by IR, UV–Vis, and X-ray single-crystal determination. The molecular geometry from X-ray determination of the title compound in the ground state has been compared using the Hartree–Fock (HF) and density functional theory (DFT) with the 6-31G(d) basis set. The calculated results show that the DFT and HF can well reproduce the structure of the title compound. The energetic behaviour of the title compound in solvent media was examined using the B3LYP method with the 6-31G(d) basis set by applying the Onsager and the polarizable continuum model (PCM). The results obtained with these methods reveal that the PCM method provides a more stable structure than Onsager's method. Using the TD-DFT method, electronic absorption spectra of the title compound have been predicted and good agreement with the TD-DFT method and the experimental determination was found. The predicted nonlinear optical properties of the title compound are much greater than those of urea. In addition, DFT calculations of the molecular electrostatic potential and NBO analysis of the title compound were carried out at the B3LYP/6-31G(d) level of theory. 相似文献
104.
We have performed two kinds of non-linear fitting procedures to the single-particle energies in the sdgh major shell to obtain better shell model results. The low-lying energy eigenvalues of the light Sn isotopes with A = 103- 110 in the sdgh-shell are calculated in the framework of the nuclear shell model by using CD-Bonn two-body effective nucleonnucleon interaction. The obtained energy eigenvalues are fitted to the corresponding experimental values by using two different non-linear fitting procedures, i.e., downhill simplex method and clonal selection method. The unknown single-particle energies of the states 2s1/2, 1d3/2, and 0h11/2are used in the fitting methods to obtain better spectra of the104,106,108,110 Sn isotopes. We compare the energy spectra of the104,106,108,110 Sn and103,105,107,109 Sn isotopes with/without a nonlinear fit to the experimental results. 相似文献
105.
The sequential reaction of the amino(trimethylsilyl)carbene complex [(CO)5W=C(NH2)C≡CSiMe3] ( 1 ) with nBuLi and [I‐Fe(CO)2Cp] affords the C(carbene)‐N bridged heterobinuclear complex [(CO)5W=C{NHFe(CO)2Cp}C≡CSiMe3] ( 2 ). Desilylation of 1 is achieved by treatment with KF in THF/MeOH. From the reaction of the resulting complex [(CO)5W=C(NH2)C≡CH] ( 3 ) with nBuLi and [I‐Fe(CO)2Cp] two binuclear WFe compounds in a ratio of approximately 1:1 are obtained: the C(carbene)‐C≡C bridged complex 4 and the C(carbene)‐N bridged complex 5 . Repetition of the deprotonation/metallation sequence yields the trinuclear WFe2 complex 6 . One Fe(CO)2Cp fragment in 6 is bonded to the amino group and the other one to the terminal carbon atom of the ethynyl substituent. The analogous reaction of 3 with nBuLi and [Br‐Ni(PMe2Ph)2Mes] gives a ca. 1:1 mixture of two heterobinuclear complexes ( 7 and 8 ). Complex 7 is bridged by the C(carbene)‐C≡C and complex 8 by the C(carbene)‐N fragment. Subsequent reaction of 7 with BuLi and [Br‐Ni(PMe2Ph)2Mes] finally affords the trinuclear WNi2 complex 9 related to 6 . The solid‐state structure of 2 is established by an X‐ray diffraction analysis. The spectroscopic data of the bi‐ and trinuclear complexes indicate electronic communication between the metal centers through the bridging group. 相似文献
106.
107.
Directing the Structural Features of N2‐Phobic Nanoporous Covalent Organic Polymers for CO2 Capture and Separation 下载免费PDF全文
Dr. Hasmukh A. Patel Sang Hyun Je Dr. Joonho Park Prof. Yousung Jung Prof. Ali Coskun Prof. Cafer T. Yavuz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(3):772-780
A family of azo‐bridged covalent organic polymers (azo‐COPs) was synthesized through a catalyst‐free direct coupling of aromatic nitro and amine compounds under basic conditions. The azo‐COPs formed 3D nanoporous networks and exhibited surface areas up to 729.6 m2 g?1, with a CO2‐uptake capacity as high as 2.55 mmol g?1 at 273 K and 1 bar. Azo‐COPs showed remarkable CO2/N2 selectivities (95.6–165.2) at 298 K and 1 bar. Unlike any other porous material, CO2/N2 selectivities of azo‐COPs increase with rising temperature. It was found that azo‐COPs show less than expected affinity towards N2 gas, thus making the framework “N2‐phobic”, in relative terms. Our theoretical simulations indicate that the origin of this unusual behavior is associated with the larger entropic loss of N2 gas molecules upon their interaction with azo‐groups. The effect of fused aromatic rings on the CO2/N2 selectivity in azo‐COPs is also demonstrated. Increasing the π‐surface area resulted in an increase in the CO2‐philic nature of the framework, thus allowing us to reach a CO2/N2 selectivity value of 307.7 at 323 K and 1 bar, which is the highest value reported to date. Hence, it is possible to combine the concepts of “CO2‐philicity” and “N2‐phobicity” for efficient CO2 capture and separation. Isosteric heats of CO2 adsorption for azo‐COPs range from 24.8–32.1 kJ mol?1 at ambient pressure. Azo‐COPs are stable up to 350 °C in air and boiling water for a week. A promising cis/trans isomerization of azo‐COPs for switchable porosity is also demonstrated, making way for a gated CO2 uptake. 相似文献
108.
Holtmann J Walczuk E Dede M Wittenburg C Heck J Archetti G Wortmann R Kuball HG Wang YH Liu K Luo Y 《The journal of physical chemistry. B》2008,112(47):14751-14761
To elucidate the dependence of the nonlinear optical (NLO) response on the conformation of triply branched derivatives, a new series of D-pi-A dendrimers has been synthesized. A combined approach of experiments (UV-vis and EOA measurements) and computational predictions (semiempirical and ab initio) was applied both on the dendrimers and on the corresponding single-strand chromophores. It has been shown that depending on the surrounding media the NLO activity of a flexible dendrimer can be very different. Two limiting cases are proposed: (i) the dendrimer resembles a solution of the corresponding single-strand chromophores with about 3-fold concentration, where the hyperpolarizability is the sum of the effect of three noninteracting single-strand subunits ("independent chromophores" limit); (ii) the dendrimers show nearly parallel or helical alignments of the single-strand subunits. Because of this change of conformation the NLO activity can be enhanced up to nine times the value of the "independent chromophores" limit and, thus, are more than a single strand chromophore. Conformers of dendrimers with interacting single-strand chromophores have been identified experimentally in nonpolar solutions by the EOA spectroscopy and possible structures have been revealed by numerical calculations, which could moreover show the tendency of the effects on the hyperpolarizability due to structural changes of the flexible dendritic architecture. Implications for future research developments are given to implement the "more than three times" concept. 相似文献
109.
Nergiz Gurbuz Serkan Demirci Serkan Yavuz Tuncer Caykara 《Journal of polymer science. Part A, Polymer chemistry》2011,49(2):423-431
Surface‐initiated reversible addition‐fragmentation chain transfer (SI‐RAFT) polymerization of N‐[3‐(dimethylamino)propyl]methacrylamide (DMAPMA) on the silicon wafer was conducted in attempt to create controllable cationic polymer films. The RAFT agent‐immobilized substrate was prepared by the silanization of hydroxyl groups on silicon wafer with 3‐aminopropylthriethoxysilane (APTS) and by the amide reaction of amine groups of APTS with ester groups of 4‐cyano‐4‐((thiobenzoyl) sulfanyl) pentanoic succinimide ester (CPSE); followed by the RAFT polymerization of DMAPMA using a “free” RAFT agent, that is, 4‐cyanopentanoic acid dithiobenzoate (CPAD) and an initiator, that is, 4,4′‐azobis‐4‐cyanopentanoic acid (CPA). The formation of homogeneous tethered poly(N‐[3‐(dimethylamino)propyl]methacrylamide) [poly(DMAPMA)] brushes, whose thickness can be tuned by reaction time varying, is evidenced by using the combination of grazing angle attenuated total reflectance‐Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, atomic force microscopy, and water contact‐angle measurements. The calculation of grafting parameters from the number‐average molecular weight, M n (g/mol) and ellipsometric thickness, h (nm) values indicated the synthesis of densely grafted poly(DMAPMA) films and allowed us to predict a polymerization time for forming a “brush‐like” conformation for the chains. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
110.
T. Gamze Ulusoy Ghobadi Amir Ghobadi Muhammed Buyuktemiz Elif Akhuseyin Yildiz Dilara Berna Yildiz H. Gul Yaglioglu Yavuz Dede Ekmel Ozbay Ferdi Karadas 《Angewandte Chemie (International ed. in English)》2020,59(10):4082-4090
Herein, we establish a simple synthetic strategy affording a heterogeneous, precious metal‐free, dye‐sensitized photoelectrode for water oxidation, which incorporates a Prussian blue (PB) structure for the sensitization of TiO2 and water oxidation catalysis. Our approach involves the use of a Fe(CN)5 bridging group not only as a cyanide precursor for the formation of a PB‐type structure but also as an electron shuttle between an organic chromophore and the catalytic center. The resulting hetero‐functional PB‐modified TiO2 electrode demonstrates a low‐cost and easy‐to‐construct photoanode, which exhibits favorable electron transfers with a remarkable excited state lifetime on the order of nanoseconds and an extended light absorption capacity of up to 500 nm. Our approach paves the way for a new family of precious metal‐free robust dye‐sensitized photoelectrodes for water oxidation, in which a variety of common organic chromophores can be employed in conjunction with CoFe PB structures. 相似文献