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.
The copper (II)-chlorophyll complex was prepared from the reaction between the chlorophyll isolated from cassava leaves and the metal ion precursor, CuSO4.5H2O in methanol under reflux for four hours. The FTIR spectra of the reaction product compared to the chlorophyll spectra show an indication of a complexation through metal coordination with the N atom from the phyrol ring replacing the magnesium (II) ion in chlorophyll.This assumption is drawn based on changes on FTIR spectra, i.e. vibration absorption originating from the CN and NH groups in the porphyrin ring and the appearance of the distinctive vibration band of nitrogen-metal bonds which is annotated as Cu-N groups at 599.88 cm-1. Another sign is the change in the OH and CO vibration bands which imply changes in aggregate properties that occur through inter-molecular interactions due to the introduction of copper (II) metal into the chlorophyll structure. The formation of copper (II)-chlorophyll compounds is also shown from the results of atomic absorption spectroscopy by recording copper metal in the product and reducing magnesium metal concentration. UV-vis spectra of chlorophyll in methanol show a characteristic band in the dark area (Soret band) at a maximum wavelength of 404 nm and the visible area (Q band) with the strongest intensity at 665 nm. These peaks appear to shift hypsochromically in the copper (II)-chlorophyll compound to 397 nm and 650 nm with higher absorptivity, indicating a change in the electronic transition of the chlorophyll after coordinating with the copper (II) ion. A new peak at 411 nm was also observed which is suggested to indicate that the copper (II) -chlorophyll complex is in an octahedral geometry in the aggregate coordinated via nitrogen atoms in the phyrol ring in place of the magnesium (II) ion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.