Browsing by Author "Tasgin, Dilek Isik"

Now showing 1 - 6 of 6

Citation - WoS: 5
Citation - Scopus: 6
A Theoretical Investigation: Effect of Structural Modifications on Molecular, Electronic, and Optical Properties of Phosphonate Substituted BODIPY Dyes
(Wiley-v C H verlag Gmbh, 2021) Tasgin, Dilek Isik; Sirin, Pinar Seyitdanlioglu; 169107
Phosphonates are important organophosphorus compounds which exhibit versatile properties in organic chemistry, medicinal chemistry, materials and biological applications. Phosphonate groups have appeared in a very few examples of BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) compounds that are important florescent dyes in these areas. The deficiency in the area motivated us to investigate how the phosphonate substituent(s) affect the structural, electronic, and optical properties of meso, alpha, or alpha, alpha '-substituted BODIPYs using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods. We have identified the suitable method as HSEH1PBE functional in combination with the basis set 6-31+G** by comparing the theoretical results with the experimental studies. Structural, electronic and optical parameters of a series of designed phosphonate substituted 12 BODIPYs (1-4) have been investigated. The alpha, and alpha, alpha '-vinyl phosphonate substituted BODIPYs (3,4) compared to meso-substituted BODIPYs (1,2) have both lower HOMO/LUMO electronic energies [(-5.57)-(-6.19)/(-3.16)-(-3.91)] and lower electronic energy gaps (E-gap) (2.11-2.42). Electrostatic potential analysis was performed for all BODIPYs to characterize their electron distribution and TD-DFT analysis was used for the absorption spectral analysis. The presented theoretical approach can be a practical guide for experimental studies for the design of new BODIPY compounds with desired properties.
Citation - WoS: 3
Citation - Scopus: 3
N-phosphorylation of pyrroles: An intramolecular migration reaction
(Pergamon-elsevier Science Ltd, 2018) Tasgin, Dilek Isik; Taşgın, Dilek; Unaleroglu, Canan; Ortak Dersler Bölümü
A new synthetic method is reported for the N-phosphorylation of pyrroles via intramolecular migration of a phosphonate diester group. The reaction proceeds under mild conditions and produces N-phosphorylated pyrrole derivatives in moderate to good yields. (C) 2018 Elsevier Ltd. All rights reserved.
Citation - WoS: 0
Citation - Scopus: 0
Pyrrolizine-3-ones: Synthesis and evaluation of photophysical properties
(Taylor & Francis inc, 2024) Tasgin, Dilek Isik; Bayraktar, Irem; 169107
We describe a synthetic approach for pyrrolizine-3-one derivatives and their photophysical properties. These compounds are prepared by a series of reactions employing the substituted pyrroles in one-pot, two-step oxidation, and intramolecular cyclization processes. The photophysical properties of the synthesized compounds were studied by using UV-Vis and fluorescence spectroscopy in different solvents. Maximum absorbance peaks were observed around 306-416 nm and maximum fluorescence emission around 603-614 nm and 465-498 nm for pyrrolyl and N-methyl pyrrolyl substituents, respectively. The introduction of a pyrrolyl substituent had a significant impact on the Stokes shifts (192-206 nm) and quantum yield values ranged from 0.002 to 0.046.
Citation - WoS: 5
Citation - Scopus: 6
Ring annulation versus alkylation of pyrrole with alpha-phosphoryl-alpha,beta-unsaturated ketones
(Pergamon-elsevier Science Ltd, 2016) Tasgin, Dilek Isik; Unaleroglu, Canan; 16910
In this study; novel aryl, heteroaryl, pyrrolyl and phosphoryl groups containing pyrrolizines were synthesized by the ring annulation reaction of aryl or heteroaryl substituted alpha-phosphoryl-alpha,beta-unsaturated ketones with pyrrole under mild reaction conditions. This domino reaction involves scandium triflate catalyzed addition of pyrrole to the double bond of alpha-phosphoryl-alpha,beta-unsaturated ketones, carbonyl group and finally ring annulation sequences. The presented work provided a convenient way for the synthesis of novel bispyrrolic compounds. (C) 2016 Elsevier Ltd. All rights reserved.
Citation - WoS: 0
Citation - Scopus: 0
Substituent-Controlled Construction of A4b2-Hexaphyrins and A3b-Porphyrins: a Mechanistic Evaluation
(Beilstein-institut, 2023) Cinar, Seda; Tasgin, Dilek Isik; Unaleroglu, Canan
A substituent-dependent construction of novel A3B-porphyrins along with A4B2-hexaphyrins was realized by the reactions of N-tosylimines and meso-aryl-substituted tripyrranes in the presence of Cu(OTf)2 as the catalyst. The reaction mechanism of the presented method was studied on model reactions by electrospray-ionization time-of-flight (HRESI-TOF) mass spectral analysis in a timely manner. The analytical results indicated that the observed azafulvene-ended di- and tripyrrolic intermediates are responsible for the formation of porphyrinogen and hexaphyrinogen forms.
Citation - WoS: 0
Citation - Scopus: 0
Vertical Self-Assembly of Gold Nanoworms for Sensitive Surface-Enhanced Raman Spectroscopy-Based Trace Detection
(Amer Chemical Soc, 2025) Khan, Ghazanfar Ali; Demir, Ahmet Kemal; Demirtas, Ozge; Tasgin, Dilek Isik; Bek, Alpan; Bhatti, Arshad Saleem; Ahmed, Waqqar
The assembly of anisotropic nanoparticles into closely packed structures results in unique functionalities. Herein, we report a 3D multilayer vertical assembly of worm-shaped Au nanoparticles using a carefully regulated evaporation-induced deposition method. With the evaporation of the nanoworm (NW) suspension, the concentration of NWs in the suspension gradually increases, which generates a balance between electrostatic interactions and entropically driven attraction to produce multilayer vertical assemblies. These assemblies exhibit enhanced surface-enhanced Raman scattering (SERS) signals due to the presence of a high concentration of hotspots. Moreover, in contrast to nanorods, the bent morphology of NWs creates pores in the vertical assembly, enabling the analyte molecule to penetrate the assembly and access hotspots. Picomolar to micromolar concentrations of rhodamine 6G (R6G) were detected with the NW assembly-based SERS substrate with excellent linearity and uniformity of the signal with a spot-to-spot relative standard deviation (RSD) of only 8.9%. The SERS substrates were also employed for trace detection of ammonium nitrate, which is a well-known constituent of homemade explosives. Our method of producing multilayer vertical assemblies of NWs is simple, highly sensitive, stable, and reproducible for making effective SERS sensors for the quantitative detection of analytes.