Browsing by Author "Zora, Metin"

Now showing 1 - 6 of 6

One-Pot Synthesis of 4-(phenylselanyl) Pyrazoles
(Pergamon-elsevier Science Ltd, 2016) Zora, Metin; Demirci, Deniz; Kivrak, Arif; Kelgokmen, Yilmaz
A facile, one-pot, general synthetic method for the preparation of 4-(phenylselanyl)pyrazoles is described. When reacted with hydrazines, alpha,beta-alkynic aldehydes produced in situ alpha,beta-alkynic hydrazones, which, upon treatment with phenylselenyl chloride, undergo cyclization to afford 4-(phenylselanyl)pyrazoles in good to high yields. This cyclization has been found to be general for a variety of in situ generated alpha,beta-alkynic hydrazones and exhibits good tolerance to a broad range of substituents, including electron-donating and electron-withdrawing groups. The enrichment of the pyrazole core with a selenyl moiety as well as with aryl and/or ferrocenyl groups may offer potential for the synthesis of molecules with pronounced or distinct biological activities. (C) 2016 Elsevier Ltd. All rights reserved.
One-Pot Synthesis of Pyrroloquinoxaline-Embedded Complex Heterocyclic Molecules
(Amer Chemical Soc, 2012) Zora, Metin; Kivrak, Arif; Yazici, Nuray Esra
Polymerization of Novel Donor Acceptor Type Functional Fluorene Derivatives at C9 Position
(Amer Chemical Soc, 2012) Carbas, Buket Bezgin; Kivrak, Arif; Onal, Ahmet Muhtar; Zora, Metin
Synthesis and Electropolymerization of a New Ion Sensitive Ethylenedioxy-Substituted Terthiophene Monomer Bearing a Quinoxaline Moiety
(Elsevier Science Sa, 2012) Carbas, Buket Bezgin; Kivrak, Arif; Zora, Metin; Onal, Ahmet M.
A new terthienyl based fluorescent polymer bearing pendant quinoxaline moieties directly attached to the 3-positions of the central thiophene ring was synthesized by electrochemical polymerization of 4-(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophen-3-yl)Pyrrolo[1,2-a]quinoxaline (EE-Q). The corresponding polymer, poly(4-(2,5-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)thiophen-3-yl)pyrrolo[1,2-a]quinoxaline) P(EE-Q), was characterized by cyclic voltammetry, FT-IR and UV-vis spectroscopy. The polymer exhibits a reversible redox behaviour (E-p(1/2) = 0.75 V) accompanied with a reversible electrochromic behavior; brownish red in the neutral state and green in the oxidized state. The band gap value for the polymer was found to be 1.75 eV. Moreover, the sensitivity of both the monomer and its polymer towards metal cations was investigated by monitoring the change in the fluorescence intensity. Among various common ions, both the monomer and its polymer were found to be selective towards Fe3+ ions by quenching the fluorescence efficiency with a Stern-Volmer constant (K-SV) of (1.9 x 10(3) M-1) and (5.0 x 10(2) M-1) for monomer and polymer solutions, respectively. (C) 2012 Elsevier B.V. All rights reserved.
Synthesis and Electropolymerization of an Ion Sensing and Fluorescent Fluorene Derivative Bearing a Quinoxaline Moiety and Its Analogues With Different Donor Units
(Elsevier, 2012) Kivrak, Arif; Carbas, Buket Bezgin; Zora, Metin; Onal, Ahmet M.
A series of new fluorene derivatives bearing pendant quinoxaline moieties with different donor groups, namely 5'H-spiro[fluorene-9,4'-pyrrolo[1,2-alquinoxaline] (FQ), 2,7-di(thiophen-2-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2-a]quinoxaline] (TQT), 2,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2-a]quinoxaline] (EQE) and 2,7-bis(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4)dioxepin-6-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2-a]quinoxaline] (PQP) were synthesized. The monomers were electropolymerized via potentiodynamic methods in order to understand the effects of donor units on the electrochemical and optoelectronic properties of the resulting polymers. It was found that polymer films exhibit reversible redox behavior accompanied with a reversible electrochromic behavior (E-p(ox) = 0.95 V for poly(2,7-di(thiophen-2-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2-a]quinoxaline]) (PTQT), E-p(ox) = 0.90 V for poly(2,7-bis(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2-a]quinoxaline]) (PEQE) and E-p(ox) = 0.67 V for poly(2,7-bis(3,3-dihexyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin-6-yl)-5'H-spiro[fluorene-9,4'-pyrrolo[1,2 a]quinoxaline]) (PPQP)). The band gap values (E-g) of the polymers were found to be 2.47, 1.93 and 1.66 eV for PTQT, PEQE and PPQP, respectively. Furthermore, the ion sensitivity of PQP and its polymer PPQP was also investigated by monitoring the change in the fluorescence intensity. Among various common ions, both PQP and PPQP were found to be selective towards Fe2+ ions by quenching the fluorescence efficiency with a Stern-Volmer constant (K-sv) of (5.9 x 10(3) M-1) and (2.7 x 10(4) M-1) for monomer and polymer solutions, respectively. (C) 2012 Elsevier Ltd. All rights reserved.
Synthesis of 4,5-Dihydropyrrolo[1,2 and Pyrrolo[1,2-A]quinoxaline Derivatives
(Amer Chemical Soc, 2012) Zora, Metin; Kivrak, Arif