scholarly journals Bandgap Energy of TiO₂/M-Chlorophyll Material (M=Cu²⁺, Fe³⁺)

2021 ◽  
Vol 24 (4) ◽  
pp. 126-135
Author(s):  
Muhammad Yusprianto ◽  
Titin Anita Zaharah ◽  
Imelda Hotmarisi Silalahi
Keyword(s):  
Metal Ion ◽  
Bathochromic Shift ◽  
Soret Band ◽  
Ester Group ◽  
Complex Compounds ◽  
Bandgap Energy ◽  
Cassava Leaves ◽  
Tauc Plot ◽  
Band Region ◽  
Light Region

The bandgap energy (Egap) of TiO2 material modified with metal-chlorophyll complex compounds (M = Cu2+, Fe3+) was observed. Chlorophyll (Chl) was isolated from cassava leaves, and its UV-Vis spectra showed absorption peaks in the Soret band region (410 nm) and in the Q band region (665 nm), which is the typical peak of chlorophyll. Copper(II)-chlorophyll complex was prepared from the reaction between chlorophyll and CuSO4.5H2O, while the iron(III)-chlorophyll was synthesized from chlorophyll and FeCl3.6H2O in methanol solvent under reflux at 65°C. The presence of copperand iron metals in the chlorophyll metal complexes was identified using Atomic Absorption Spectroscopy in methanol solution. The absorption of copper measured in Cu2+-Chl was 0.0488 (0.4805 mg/L), while the iron atom in Fe3+-Chl was 0.0050 (0.0195 mg/L). The UV-vis spectra demonstrate the hypsochromic shift of the Soret band to 405 nm (Cu2+-Chl) and 402 nm (Fe3+-Chl). The Infrared spectra of chlorophyll after being complexed with copper(II) shows the increase of vibrational absorption wavenumber of the C=N group from 1225.06 cm-1 to 1241.94 cm-1 indicates the coordination of the metal ion on the N atom in the pyrrole ring. The shift in the absorption band on the Fe3+-Chl spectrum was seen for the C=O ester group from 1720.49 cm-1 to 1721.10 cm-1 indicating the metal ion bonding in the C=O group of esters. The DR-UVis analysis of TiO2/metal-chlorophyll shows a bathochromic shift towards the visible light region. By using the Tauc plot method, it was observed that the Egap of TiO2 reduces from 3.08 eV to 2.89 eV and 2.93 eV in the compound of TiO2/Cu2+-Chl and TiO2/Fe3+-Chl, respectively.

scholarly journals Boron Carbide Nanowires from Castor Oil for Optronic Applications: A Low-Temperature Greener Approach

2020 ◽  
Author(s):  
H. V. Saritha Devi ◽  
M. S. Swapna ◽  
S SANKARARAMAN
Keyword(s):  
Low Temperature ◽  
Boron Carbide ◽  
Castor Oil ◽  
Light Emission ◽  
Bandgap Energy ◽  
X Ray Diffraction ◽  
Blue Light Emission ◽  
Tauc Plot ◽  
Plot Analysis ◽  
Cie Plot

Abstract The development of one-dimensional nanostructures has revolutionized electronic and photonic industries because of their unique properties. The present paper reports the low-temperature green synthesis of boron carbide nanowires, of diameter 14 nm and length 750 nm, by the condensation method using castor oil as the carbon precursor. The nanowires synthesized exhibit beaded chain morphology, and bandgap energy of 2.08 eV revealed through the Tauc plot analysis. The structure of boron carbide nanowires is revealed by Fourier transform infrared spectroscopy and X-ray diffraction analyses. The photoluminescence study reveals the nanowire's blue light emission capability under ultraviolet excitation, which is substantiated by the CIE plot suggesting its potential in photonic applications.

One-pot synthesis of 5-(8-ethoxycarbonyl-1-naphthyl)-10,15,20-triphenyl porphyrin (ENTPP) and spontaneous resolution upon crystallization

2011 ◽  
Vol 15 (03) ◽  
pp. 197-201 ◽  
Author(s):  
Juanxia Yang ◽  
Jiaxun Jiang ◽  
Weiguang Fang ◽  
Xiaoxu Kai ◽  
Chuanjiang Hu ◽  
...  
Keyword(s):  
Soret Band ◽  
Ester Group ◽  
Spontaneous Resolution ◽  
Cd Spectra ◽  
One Pot ◽  
Nmr Spectrum ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Entire Structure

5-(8-ethoxycarbonyl-1-naphthyl)-10,15,20-triphenyl porphyrin (ENTPP) has been synthesized in a one-pot reaction, and the corresponding chiral crystalline samples have been obtained by spontaneous resolution. 1 H NMR spectrum suggests it is mononaphthyl substituted species and an ethyl group is over the porphyrin plane. The structure has been further confirmed by X-ray crystallography. ENTPP·C6H14 (C57H50N4O2 ): monoclinic, P21, a = 10.707(2) Å, b = 12.203(2) Å, c = 17.858(4) Å, β = 103.06(3)°, V = 2272.8(8) Å3, Z = 2. The 8-position substituent, ester group, lies above the porphyrin plane and leads to the conformational chirality. The entire structure is built up with homochiral molecules, which leads to a chiral crystal through packing in P21 space group. Circular dichroism (CD) spectra have exhibited remarkable absorptions in the Soret band region, which further confirms the homochirality of the crystalline samples.

Quasi-line vibronic spectra of 2,3,12,13-tetramethyldibenzoporphine and their interpretation

2003 ◽  
Vol 07 (12) ◽  
pp. 787-794 ◽  
Author(s):  
Konstantin N. Solovyov ◽  
Serguei M. Arabei ◽  
Lev L. Gladkov ◽  
Vera K. Konstantinova ◽  
Alisa E. Turkova ◽  
...  
Keyword(s):  
Soret Band ◽  
Normal Coordinate Analysis ◽  
Free Base ◽  
Normal Coordinate ◽  
Excitation Spectra ◽  
Fluorescence Excitation ◽  
Vibronic Spectra ◽  
Band Region ◽  
Fluorescence Excitation Spectra

The quasi-line fluorescence and fluorescence excitation spectra of 2,3,12,13-tetrame-thyldibenzoporphine have been obtained at 77 K in n-octane and analyzed. The normal-coordinate analysis of this molecule has been performed, and the spectra have been interpreted in detail. In the Soret band region the fluorescence excitation quasi-line spectra clearly reveal two 0-0 components. The problem of the nature of the Soret band of free-base porphyrins is discussed.

Electrochemistry and spectroelectrochemistry of 5,10,15,20-tetrakis(1,3-benzodioxole) porphyrin and its manganese and iron complexes

2014 ◽  
Vol 18 (12) ◽  
pp. 1093-1100 ◽  
Author(s):  
Geani Maria Ucoski ◽  
Shirley Nakagaki ◽  
Fábio Souza Nunes
Keyword(s):  
Metal Ion ◽  
Supporting Electrolyte ◽  
Cation Radical ◽  
Soret Band ◽  
Iron Complexes ◽  
Structural Features ◽  
Cyclic Voltammograms ◽  
Free Base ◽  
Typical Experiment ◽  
Semi Empirical

Cyclic voltammetry and thin-layer spectroelectrochemical properties of the free base 5,10,15,20-tetrakis(1,3-benzodioxole)porphyrin ( H 2 P ), and its manganese and iron complexes ( MnP and FeP , respectively) were studied in dichloromethane with tetra-butyl ammonium hexafluorophosphate (TBAPF6) as supporting electrolyte. The free base undergoes two monoelectronic oxidations at +0.71 and +0.96 V vs.  Ag / Ag +, corresponding to the formations of the π-cation radical and dication. Two reductions were observed at -1.53 and -1.87 V corresponding to the formation of π-anion and dianion species. The cyclic voltammograms of the Mn III and Fe III complexes also showed a reversible process centered in the metal ion with E1/2 values at -0.61 and -0.59 V, respectively. In a typical experiment, in situ spectroelectrochemical response showed a decrease of the Soret band at 422 nm, a red shift of the Q-bands, and the new low intensity bands between 800–950 nm range. Structural features and spectroscopic assignments were proposed and discussed based on semi-empirical (molecular mechanics MMFF and ZINDO/S (Zerner method of intermediate neglect of differential overlap for spectroscopy) calculations.

scholarly journals Synthesis of Cr(III)-Morin Complex: Characterization and Antioxidant Study

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Qadeer K. Panhwar ◽  
Shahabuddin Memon
Keyword(s):  
Metal Ion ◽  
Bathochromic Shift ◽  
Peak Shift ◽  
Ring System ◽  
Water Molecules ◽  
Nmr Studies ◽  
H Nmr ◽  
Crystalline Water ◽  
Complex Characterization ◽  
Stable Ring

The complex formation between Cr(III) and morin was carried out in methanol and confirmed by analytical characterization using UV-Vis, IR,1H NMR, and TG-DTA. UV-Vis shows significant bathochromic shift in benzoyl upon coordination as well as IR well illustrates the peak shift of C=O group and formation of a O–Cr(III) bond. Likewise,1H NMR studies clarify that Cr(III) metal ion replaces the 5OH proton hence; 5-hydroxy-4-keto site is employed by morin in chelation to form six-membered stable ring system out of three available chelating sites. In addition, TG-DTA denotes the presence of coordinated and crystalline water molecules. The melting point of the complex was found to be 389°C by DSC. In addition, Cr(III)-morin complex was found to be a more potent antioxidant than morin as evaluated by DPPH• and FRAP methods.

scholarly journals COMPLEX COMPOUNDS OF LANTANOIDS WITH 4 - [(2,4-DIMETOXYBENZYL) AMINO] BENZOIC ACID.

2021 ◽  
Vol 2 (68) ◽  
pp. 57-60
Author(s):  
M. Shamsutdinova ◽  
F. Dzhebirkhanova
Keyword(s):  
Thermal Stability ◽  
Benzoic Acid ◽  
Coordination Compounds ◽  
Metal Ion ◽  
Earth Metal ◽  
Complex Compounds ◽  
Carboxyl Group ◽  
Mercury Lamp ◽  
Infrared Absorption Spectra ◽  
Amino Benzoic Acid

The synthesis of complex compounds of 4 - [(2,4-dimethoxybenzyl) amino] benzoic acid (HL) with ions of samarium (III), europium (III), terbium (III), gadolinium (III) and dysprosium (III). According to the data of elemental analysis and thermogravimetry, the obtained complexes are hydrates of the composition LnL3 · nH2O, where n = 0-2. The area of their thermal stability is in the range from 100 ° С to 150 ° С. Electronic and infrared absorption spectra of the ligand and complexes with rare-earth metal ions have been measured. According to the IR spectra, the coordination of the ligand with the metal ion occurs at the carboxyl group. The carboxyl group is bidentate coordinated. To excite luminescence, a line of a mercury lamp with a wavelength of 248 nm was used. The highest luminescence intensity is observed for the coordination compounds Eu3 +, Tb3 +, Sm3 +, and Dy3 +.

Metallophthalocyanines for antimicrobial photodynamic therapy: an overview of our experience

2013 ◽  
Vol 17 (06n07) ◽  
pp. 399-416 ◽  
Author(s):  
Vanya N. Mantareva ◽  
Ivan Angelov ◽  
Dieter Wöhrle ◽  
Ekaterina Borisova ◽  
Vesselin Kussovski
Keyword(s):  
Photodynamic Therapy ◽  
Metal Ion ◽  
Soret Band ◽  
Quantum Yields ◽  
Anionic Complex ◽  
Antimicrobial Photodynamic Therapy ◽  
Metal Phthalocyanine ◽  
Metal Phthalocyanines ◽  
The Media ◽  
Positively Charged

Metal phthalocyanine complexes with different charges, hydrophobicity and metal ions were synthesized and studied for antimicrobial photodynamic therapy of pathogenic bacterial and fungal model strains. Ten positively charged complexes with the metals Zn ( II ), Al ( III ), Ga ( III ), In ( III ), Si ( IV ) and Ge ( IV ) in the center of the ligand and substituents at the ligand bearing four or eight N-alkylpyridyloxy groups were prepared. In addition, a negatively charged Zn ( II )-phthalocyanine with four sulfophenoxy-groups was synthesized. The absorption spectra showed low intensity of the Soret band in the UV part of the spectrum and the intense Q-band in the red to far red region (λ = 671–697 nm). The fluorescence was determined with quantum yields between 0.1–0.33 and life-times 2.8–4.9 ns in dependence of the kind of metal ion and the substituents. In organic solvents all complexes exist in a monomeric state but in aqueous solution they show aggregation with the exception of Ga ( III ) phthalocyanines. The singlet oxygen quantum yields were evaluated in dependence on the metals, substituents and the media with values between 0.16–0.68. The cationic metal phthalocyanines were taken-up by pathogenic cells in a higher amount as compared to the anionic complex. Three of the studied phthalocyanines namely tetra-N-methylpyridyloxy-phthalocyanine Zn ( II ) and tetra- and octa-N-methylpyridyloxy- Ga ( III ) phthalocyanines showed a high photodynamic efficacy towards most of the studied microorganisms in suspensions.

scholarly journals Ethyne Functionalized Meso-Phenothiazinyl-Phenyl-Porphyrins: Synthesis and Optical Properties of Free Base Versus Protonated Species

Molecules ◽  
2020 ◽  
Vol 25 (19) ◽  
pp. 4546
Author(s):  
Eva Molnar ◽  
Emese Gál ◽  
Luiza Găină ◽  
Castelia Cristea ◽  
Luminița Silaghi-Dumitrescu
Keyword(s):  
Absorption Spectra ◽  
Density Functional ◽  
Photophysical Properties ◽  
Bathochromic Shift ◽  
Fluorescence Emission ◽  
Soret Band ◽  
Quantum Yields ◽  
Free Base ◽  
Wave Absorption ◽  
Long Wave

Synthesis, structural characterization and photophysical properties for a series of new trans-A2B2- and A3B-type ethynyl functionalized meso-phenothiazinyl-phenyl porphyrin derivatives are described. The new compounds displayed the characteristic porphyrin absorption spectra slightly modified by weak auxochromic effects of the substituents and fluorescence emission in the range of 651–659 nm with 11–25% quantum yields. The changes recorded in the UV-vis absorption spectra in the presence of trifluoroacetic acid (TFA) are consistent with the protonation of the two internal nitrogen atoms of the free-base porphyrin (19 nm bathochromic shift of the strong Soret band and one long wave absorption maxima situated in the range of 665–695 nm). Protonation of the phenothiazine substituents required increased amounts of TFA and produced a distinct hypsochromic shift of the long wave absorption maxima. The density functional theory (DFT) calculations of a porphyrin dication pointed out a saddle-distorted porphyrin ring as the ground-state geometry.

Synthesis, Characterization and Visible Light Photocatalytic Properties of BiOCl0.2Br0.1I0.7

2011 ◽  
Vol 52-54 ◽  
pp. 2094-2098 ◽  
Author(s):  
Kai Jin Huang ◽  
Hou Guang Liu ◽  
Chang Sheng Xie
Keyword(s):  
Visible Light ◽  
Electric Fields ◽  
Photocatalytic Properties ◽  
Bandgap Energy ◽  
Obvious Effect ◽  
Light Region ◽  
Powder Samples ◽  
Wet Chemical ◽  
First Time ◽  
Visible Light Photocatalytic

The ternary solid solution BiOCl0.2Br0.1I0.7 was successfully synthesized using a wet chemical method. The visible light photocatalytic properties of BiOCl0.2Br0.1I0.7 were investigated for the first time. Powder samples were characterized by XRD, SEM, UV-vis spectrophotometry and nitrogen sorption. BiOCl0.2Br0.1I0.7 absorbs intensely in the visible light region and the optical bandgap is 1.82eV. The chlorine and the bromine elements have an obvious effect in changing the bandgap energy and the particle size of the catalysts. The deep valance band edge position, the internal electric fields and the morphology give the BiOCl0.2Br0.1I0.7 best visible light photocatalytic properties.

Porphyrins as spectroscopic sensors for conformational studies of DNA

2007 ◽  
Vol 79 (4) ◽  
pp. 801-809 ◽  
Author(s):  
Milan Balaz ◽  
Klaus Bitsch-Jensen ◽  
Angela Mammana ◽  
George A. Ellestad ◽  
Koji Nakanishi ◽  
...  
Keyword(s):  
Dna Sequence ◽  
Conformational Changes ◽  
Soret Band ◽  
Sensitive Detection ◽  
Electronic Circular Dichroism ◽  
Conformational Studies ◽  
Molecular Systems ◽  
Band Region ◽  
Spectroscopic Sensors ◽  
Covalently Linked

Molecular systems containing two or more interacting porphyrins show remarkable spectroscopic features that allow for a very sensitive detection of conformational changes on the microscale level by different methods, such as fluorescence and electronic circular dichroism (ECD). Covalent porphyrin-DNA assemblies can provide a CD profile (exciton couplet) within the porphyrin Soret band region which is very diagnostic for DNA conformational changes. Additionally, covalently linked porphyrins have been shown to function as DNA molecular caps and to stabilize the non-self-complementary non-Watson-Crick guanine-adenine DNA sequence via their strong π-π stacking.

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