Browsing by Author "Carbas, Buket Bezgin"

Now showing 1 - 5 of 5

Electrosynthesis of a New Indole Based Donor-Acceptor Type Polymer and Investigation of Its Electrochromic Properties
(Elsevier Science Sa, 2017) Carbas, Buket Bezgin; Kivrak, Arif; Kayak, Emrah
The purpose of this research is to synthesize a novel monomer, namely, 1-mety1-2,3-di(thiophen-2-y1)-1H-indole (DTI) and to present optical and electrochemical characterization of its corresponding polymer film, P(DTI). The donor thiophene unit was matched with acceptor indole unit in consideration of donor acceptor-donor approach in order to achieve DTI monomer. This monomer was electropolymerized in the medium 0.1 M LiClO4/Ethanol:ACN solution mixture and a conductive indole based polymer, P(DTI) was obtained. The spectroelectrochemical studies show that P(DTI) has a band gap of 2.45 eV and a color change from pale green to dark green with a switching time of 0.9 s during oxidation and a high coloration efficiency (286 cm(2)/C) at 830 nm. Furthermore, P(DTI) shows good environmental and redox stability with a retention of 85% after 1500th switching. (C) 2016 Elsevier B.V. All rights reserved.
Optical, Electrochemical and Dft Studies of Donor-Acceptor Typed Indole Derivatives
(Elsevier, 2023) Carbas, Buket Bezgin; Noori, Hussein Ali; Kavak, Emrah; Kaya, Yasemin; Kivrak, Arif
The donor-acceptor type indole chromophore motif presents an interesting molecular architecture to the scientific world, unfortunately, as in every special and beautiful formation needed; their synthesis represents a synthesis challenge. In the current search, new donor-acceptor typed indole derivatives, 1-methyl-phenyl-3-aldehyde indole (HAN-1), 2-(((1-methyl-2-phenyl-1H-indol-3-yl)methylene)malononitrile ( HAN-2), 1-ethyl-2-phenyl-3-aldehyde indole (HAN-3), 2-((1-ethyl-2-phenyl-1H-indol-3-yl)methylene)malononitrile (HAN-4) were successfully synthesized and the results supported with FTIR and NMR spectra analysis. All the molecules undergo excited state intramolecular electron transfer with unique charge transfer reaction. Their electrochemical and optical properties were investigated in relation to the acceptor effect of functional groups on the indole units in the conjugated structure. Density functional theory (DFT) calculations exhibited that higher electron withdrawing ability strength resulted in decreased HOMO-LUMU gaps of the molecules. Futhermore, donor acceptor typed indole derivatives undergo irreversibly one electron oxidation in the medium of 0.1 M TBAPF(6)/ACN solution with a similar onset oxidation potentials. Both experimental and theoretical studies showed that the electron withdrawing ability of the molecules affect more LUMO energy level of the molecules. Moreover, they suggest that donor acceptor indole molecules herein are potential candidates for fabrication of dye synthesized solar cells. (C) 2022 Elsevier B.V. All rights reserved.
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.