DFT and TDDFT investigation of the Schiff base formed by tacrine and saccharin

WOS: 000394169500017PubMed ID: 28035644Schiff bases have many chemical and biological applications in medicine and pharmaceuticals due to the presence of an imine group (-C=N-). These bases are used in many different fields of technology, and in photochemistry because of their photochromic properties. Here, the structural and electronic properties of the Schiff base formed by tacrine and saccharin (TacSac) were explored using density functional theory with the B3LYP, M06-2X, M06L, and omega B97XD functionals in combination with the 6-311++G(d,p) basis set. The time-dependent formalism was used at the B3LYP/6311++G(d, p) level to obtain electronic transitions. The calculations were repeated in an implicit solvent model mimicking water, using the polarizable continuum model in conjunction with a solvation model based on a density approach. The results indicate that TacSac cannot form spontaneously, but can be obtained in mild reactions. However, the resulting Schiff base displays different characteristics to its monomers. It also has the potential for use in photochemical intramolecular charge-transfer systems

A DFT and TDDFT investigation of interactions between 1-hydroxypyrene and aromatic amino acids

WOS: 000364611600002This study presents a computational investigation of formation photoinduced charge transfer complexes between 1-hydroxypyrene (PyOH) and aromatic amino acids (Phenylalanine: Phe, Tyrosine: Tyr, Tryptophan: Trp) in gas phase and in water. Geometry optimizations were performed by density functional theory (DFT) at omega B97XD/6-31 1++G(d,p) level. Time-dependent density functional theory (TDDFT) was used to calculate the electronic transitions of molecules at B3INP/6-311++G(d,p) and CAM-B3LYP/6-311++G(d,p) levels using the ground-state geometries from omega B97XD/6-311++G(d,p). Polarizable Continuum Model (PCM) is used for calculations in water. Total electronic energies, complexation energies, free energy differences, solvation energies, excitation wavelengths, and HOMO-LUMO energy gaps of complexes have been analyzed and compared in gas phase and in solution. The intermolecular distances between PyOH and amino acids increased in water compared to the gas phase. The optimized complexes display an increasing complex stability in the order Trp > Tyr > Phe. Analyses of first excited singlet states have revealed that there are charge transfers between PyOH and amino acids through pi-pi stacking except PyOH-Phe complexes in both media. The charge distributions increased in water. Among all studied systems, PyOH-Trp systems have the most significant charge transfer between HOMO-1 and LUMO (full CT, 59%). However, dipole moment and oscillator strength of this transition (S-0-S-1) are weaker compared to the other studied systems. PyOH-Trp systems are determined to be the best model to investigate and design bioorganic photosensitive materials with its charge transfer character. (C) 2015 Elsevier B.V. All rights reserved.Ege UniversityEge University [2012 FEN 051]The authors gratefully acknowledge Ege University for financial support of this research work (BAP Project No: 2012 FEN 051)

Synthesis, Conductivity, and Impedance Studies on Metallophthalocyanines Formed Across Adjacent Rings

WOS: 000458689800005The synthesis and characterization of Co-II, Zn-II, and Ni-II phthalocyanines (Pcs) 4, 5, and 6, respectively, containing two bis[2-(4-hydroxyphenyl)-2-propyl]benzene groups formed across adjacent rings at the peripheral positions are described. The Pcs were synthesized by cyclotetramerization of the previously prepared precursor 4,4 '-bis[1,3-propylbenzene-2-p-phenoxy]phthalonitrile (3) in the presence of metal salt in boiling dry DMF under a dry nitrogen atmosphere. Elemental analysis, UV-Vis, FT-IR, and H-1-NMR spectroscopy, as well as MALDI-TOF mass spectrometry techniques were used for the characterization of 4. Conductivity (dc and ac) and impedance spectroscopy (IS) measurements were performed on the films of 5 and 6 between the temperatures 293 and 523 K and frequencies 40 and100 kHz. The dc conductivity values were calculated as 2.11 x 10-(10), 3.48 x 10-(10), and 1.90 x 10-(10) S/cm for the films of 4, 5, and 6, respectively, at room temperature. Activation energy values of the films were also calculated. Conductivity (ac) results suggest that the dominant charge transport mechanisms can be explained by the hopping model depending on temperature and frequency range. From impedance spectra and Cole-Cole plots, the relaxation time in the Debye dispersion relation is considered as a distribution of relaxation time values rather than as a single relaxation time. To elucidate the structural, spectroscopic, and bonding properties of the obtained compounds, DFT/TD-DFT calculations were performed.Scientific Research Commission of Marmara University (BAPKO)Marmara University [FEN-BGS-290506-0114]; Turkish Academy of Sciences (TUBA)Turkish Academy of SciencesThe authors gratefully acknowledge financial support by the Scientific Research Commission of Marmara University (BAPKO Project No: FEN-BGS-290506-0114), the Turkish Academy of Sciences (TUBA), and computer time on the FenCluster provided by the Ege University Faculty of Science and TUBITAK-ULAKBIM Truba Resources

Novel lutetium(III) phthalocyanine-coumarin dyads; synthesis, characterization, photochemical, theoretical and antioxidant properties

In this study, novel 7-oxy-3-ethyl-6-hexyl-4-methylcoumarin substituted lutetium(III) phthalocyanine compounds were synthesized, characterized and their photochemical, theoretical, and antioxidant properties were examined. All complexes were characterized by common spectroscopic methods such as FT-IR, UV?vis, 1H NMR, MALDI-TOF-MS and elemental analysis as well. Geometry optimization of phthalocyanine compounds was calculated in the B3LYP functional using 6-31G (d, p) + SDD basis set of the Density Functional Theory. Aggregation, singlet oxygen generation, and photodegradation behavior under light irradiation of the complexes (1?4) were investigated in dimethylformamide. The three phthalocyanine compounds (1, 2, and 4) showed a high level of singlet oxygen efficiency were compared with the unsubstituted zinc(II) and lutetium(III) phthalocyanine compounds because their quantum yield values were found to be over 0.80. The radical cation scavenging activities of the compounds 3 (120.344 mM trolox/mg) and 4 (188.733 mM trolox/mg) are quite remarkable in 2,2?-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid analysis according to butylated hydroxyanisole (52.63 mM trolox/mg)

Synthesis, characterization, third-order non-linear optical properties and DFT studies of novel SUBO bridged ball-type metallophthalocyanines

Acar-Selcuki, Nursel/0000-0001-9292-0637; alizadeh, shabnam/0000-0003-3601-807X; Salih, Bekir/0000-0002-8542-6531; Ozer, Metin/0000-0002-1173-2405; Gork, Gulsen/0000-0003-3947-6332WOS:000599093600024PubMed: 33201973Novel 4,4 '-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy)) (SUBO) bridged ball-type metallophthalocyanines were synthesized starting from 4,4 '-(((2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropane-2,1-diyl))bis(oxy))diphthalonitrile with convenient metal salts in 2-N,N-dimethylaminoethanol. A new bisphthalonitrile compound was obtained from 2,2 '-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)bis(2-methylpropan-1-ol) and 4-nitrophthalonitrile in acetonitrile at reflux temperature in the presence of potassium carbonate as a catalyst. The structural characterization of the compounds was performed by elemental analysis, and infrared, ultraviolet-visible and matrix-assisted laser desorption/ionization time-of-flight mass spectroscopic methods. Nonlinear absorptions of the phthalocyanine complexes were measured using the Z-scan technique with 7 ns pulse duration at a 532 nm wavelength. It is obvious that ball-type copperphthalocyanine has a high nonlinear absorption coefficient and imaginary component of the third-order susceptibility compared to other complexes. Therefore, ball-type copperphthalocyanine can be regarded as a very good candidate for optical limiting applications. Density functional theory was used for geometry optimizations and time-dependent density functional theory calculations of electronic transitions in order to compare with the experimental results. Molecular orbital and nonlinear optical analyses were also performed with density functional theory at the CAM-B3LYP/6-31G(d,p)/LANL2DZ level. The nonlinear optical analyses show that ball-type copperphthalocyanine has significantly better nonlinear optical properties in comparison to a common reference compound, urea.Ministry of Development-Republic of TurkeyTurkiye Cumhuriyeti Kalkinma Bakanligi [2016 K121230]; Turkish Academy of Science (TUBA)Turkish Academy of Sciences; Marmara University Scientific Research Project Coordination Unit (BAPKO)Marmara University [FEN-B-101018-0525]This work was supported by the Ministry of Development-Republic of Turkey with the project Number: 2016 K121230. ozer Bekarolu and Bekir Salih gratefully acknowledge the Turkish Academy of Science (TUBA) for the partial financial support. This work was also supported by the Marmara University Scientific Research Project Coordination Unit (BAPKO) with the project number (FEN-B-101018-0525). Computer time provided by Fen Cluster (Ege University Faculty of Science) and TUBITAK ULAKBIM TRUBA Resources is gratefully acknowledged

Spectroscopic, electrochemical and electrocolorimetric properties of novel 2-(2 '-pyridyl)-1H-benzimidazole appended bay-substituted perylene diimide triads

WOS: 000470951400008In this study, four new perylene diimide (PDI) derivatives incorporating 2-(2'-pyridyl)-1H-benzimidazole (2PBI) chromophores at the imide positions, in which 1 bearing non-bay-substituted perylene core, and those having four substituents at 1,6,7,12-bay positions of the perylene core, namely 2 bearing electron-withdrawing chlorine atoms, 3 bearing electron-donating 4-methoxyphenoxy groups and 4 bearing non-electron-donating 4-tert-butylphenoxy groups, respectively were synthesized and fully characterized by FT-IR, H-1 NMR, C-13 NMR, MALDI-TOF mass spectrometry and UV/Vis spectroscopy. The thermal properties were measured by thermogravimetric analysis (TGA) which showed that the materials (1-4) are thermally very stable (T-d > 450 degrees C). DFT was performed for geometry optimizations, and TDDFT was used to compare the calculated and the experimental UV/Vis electronic spectra at the B3LYP/6-311 G(d) level. Detailed measurements were carried out by the use of electroanalytical, spectroscopic and colorimetric techniques in order to understand redox natures, color changes and optoelectronic characters of the novel compounds. These 2PBI-functionalized PDI triads showed reversible reduction processes, chemically stable reduced species and considerably low HOMO-LUMO band gaps, as the new worthy members of photoactive charge transport materials for optoelectronic and photovoltaic systems. In addition, with distinct color changes associated with their redox processes in the solution, these new triads displayed great capacity for application in electrochromic devices. The emission maxima of the compounds were found to be red shifted in the solid state.Turkish Scientific and Technical Research Council [TUBITAK]Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [214Z090]; Turkish Academy of SciencesTurkish Academy of SciencesThe authors are grateful to the Turkish Scientific and Technical Research Council for support of this project under the grant [TUBITAK-Project No: 214Z090]. Computations were performed using resources at the TUBITAK-ULAKBIM Truba and Fen Cluster by Ege University, Faculty of Science. A. R. Ozkaya and B. Salih thank the Turkish Academy of Sciences for partial financial support

Tetrahydroxyphthalocyanine as a potential nonlinear optical material

We have synthesized a new zinc(II)-phthalocyanine (ZnPc) incorporating hydroxyl groups at the pe-ripheral positions. This new zinc(II)-tetra-hydroxyphthalocyanine ( 1 ) has been characterized by high -resolution MALDI TOF MS, UV-Vis, FT-IR (ATR), and 1 H-and 13C-NMR techniques, and further by the electrochemical measurements. DFT and TD-DFT computations were performed to model plausible struc-ture and also analyze the electronic structure and optical properties of 1 . The effects of the polarity and hydrogen bonding ability of the hydroxyl substituents on the peripheral positions of 1 on the optical and electrochemical properties are reported in this study. The redox behavior of 1 in dimethyl sulfoxide (DMSO) was determined by voltammetry and colorimetry supported in situ spectroelectrochemistry. The nonlinear absorption and optical limiting (OL) properties of 1 were measured in tetrahydrofuran (THF) by utilizing the open aperture Z-scan technique with nanosecond pulses at 532 nm. The sample demon-strated good reverse saturable absorption and OL behaviors. The ultrafast pump-probe experiments re-vealed the intersystem crossing (ISC) mechanism (triplet-triplet transition) and the nonlinear absorption mechanism of the compound. The results indicate that this new phthalocyanine ( 1 ) can be considered a potential candidate for low-power OL applications.(c) 2022 Elsevier B.V. All rights reserved.Zonguldak Buelent Ecevit University [2015-72118496-05]; Turkish Academy of Sciences (TUBA)The authors thank Zonguldak Buelent Ecevit University for financial support under the project [BAP Project No: 2015-72118496-05 ]. Computer time on TUBITAK-ULAKBIM Truba resources are greatly acknowledged. Ali Riza OEzkaya and Bekir Salih also thank the Turkish Academy of Sciences (TUBA) for partial support to this study

A novel AB(3)-type trimeric zinc(II)-phthalocyanine as an electrochromic and optical limiting material

Acar-Selcuki, Nursel/0000-0001-9292-0637; Salih, Bekir/0000-0002-8542-6531; KARATAY, Ahmet/0000-0001-9373-801X; ISIK BUYUKEKSI, Sebile/0000-0002-6075-1725WOS: 000587715700019PubMed: 32959851Recent advances in the practical applications of metallophthalocyanines (MPcs) in different technological fields have stimulated us to design and synthesize a new asymmetric AB(3)-type trimeric zinc(II)-phthalocyanine (1). This bulky and high molecular weight compound was characterized by elemental analysis, H-1, C-13 DEPT, and H-1-H-1 NOESY NMR, HR MALDI-TOF mass spectrometry, UV-vis, and FT-IR (ATR) techniques. In-depth electrochemical studies show that 1 displays quasi-reversible three one-electron reductions and two one- or two-electron oxidation processes, rather than any redox processes including the transfer of three-electrons in one-step. Besides this, in situ spectroelectrochemical measurements suggest the good application potential of 1 as an electrochromic material in display technologies. A study of the nonlinear optical properties (NLOs) of 1 reveals that the poly(methylmethacrylate) (PMMA) composite film displays a much larger nonlinear absorption coefficient and a lower saturable absorption threshold for optical limiting when compared to the same Pc molecules in solution. Ultrafast transient absorption measurements reveal the intersystem crossing mechanism. Density functional theory (DFT) was used for the geometry optimizations and time dependent-DFT (TD-DFT) for HOMO/LUMO energies and electronic transitions for 1.Zonguldak Bulent Ecevit University [BAP Project]Bulent Ecevit University [2015-72118496-05]; Turkish Academy of Sciences (TUBA)Turkish Academy of SciencesThe authors are grateful to Zonguldak Bulent Ecevit University for financial support under the project [BAP Project No: 2015-72118496-05]. Some of the calculations were performed on Fencluster (Ege University, Faculty of Science) and TUBITAK-ULAKBIM Truba resources. Ali Riza Ozkaya and Bekir Salih also thank the Turkish Academy of Sciences (TUBA) for partial support for this work