Natural photosensitizer extraction from Delonix regia flowers for future photosensor for DSSCs applications

This study explores the utilization of Delonix regia (DR) (Gulmohar flower) as a natural photosensitizer in the fabrication of self-powered photosensors via dye-sensitized solar cells (DSSCs). Various photoanodes, including ZnO, ZnO/TiO2, and ZnO/TiO2/Nb2O5, were investigated for their performance enhancement in DR-based photosensors. The photoanodes were fabricated using different deposition methods sensitized with DR photosensitizer and characterized through X-ray diffraction analysis, Field emission scanning electron microscopy (FE-SEM), UV–visible, Fluorescence spectroscopy, and Fourier transform infrared spectroscopy (FTIR) analysis. The absorbance spectrum results indicate improved photosensitizer adsorption in visible light for the ZnO/TiO2/Nb2O5/DR photoanode compared to other configurations. The scanning electron microscopy (SEM) cross-section image of ZnO/TiO2/Nb2O5 confirmed the formation of a multilayer photoanode. Chronoamperometry experiments were conducted to evaluate the photo sensing behavior, focusing on sensitivity, photoresponsivity, specific detectivity, and quantum efficiency within the solar spectrum range. Among the devices, ZnO/TiO2/Nb2O5 exhibited the highest photoresponsivity (1.2 × 10 −3 A/W) and photodetectivity (26.78 × 104 Jones), demonstrating promising advancements in DR-sensitized photosensors. This research highlights the exceptional performance of DR-sensitized photoanodes, particularly ZnO/TiO2/Nb2O5, in advancing the capabilities of photo-sensing devices. The investigated configuration exhibited a rapid response speed of 723 ms and a remarkable sensitivity of 89.87% in detecting photo signals. These findings emphasize the potential of DR photosensitizers to enhance photo-sensing activities, with significant implications for diverse applications in photodetection. By leveraging the unique properties of DR, particularly its incorporation into ZnO/TiO2/Nb2O5, this study underscores the promising prospects for developing efficient self-powered photosensors. The insights gleaned from this work pave the way for further exploration and optimization in organic photosensors

A first report of the complexes of 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarboxymethoxy-26,28-dihydroxycalix[4]arene with Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II)

Totally six dinuclear complexes of Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) of calix[4]arene derivatized with two pendants possessing terminal –COOH functions at two of its alternate phenolic –OH groups were synthesized for the first time and were well characterized.© Elsevie

A first report of the complexes of 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarboxymethoxy-26,28-dihydroxycalix[4]arene with Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II)

Totally six dinuclear complexes of Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) of calix[4]arene derivatized with two pendants possessing terminal –COOH functions at two of its alternate phenolic –OH groups were synthesized for the first time and were well characterized.© Elsevie

Mono- and di-nuclear Cu(II) complexes of <i>p-tert</i>-butyl-calix[4]arene-1,3-diacid , derivative: A comparative study of their characterization and catecholase mimetic activity

853-857Reaction of copper(II) perchlorate with p-tert-butyl-calix[41arene- 1,3-diacid gives mono-nuclear complex in acetonitrile and dinuclear complex in methanol which have been isolated as their pyridine bound adducts. The dinuclear complex exhibits different characteristics in its EPR and magnetic studies. The reactivity studies clearly indicate that the dinuclear complex has higher catecholase mimetic activity over its mononuclear counterpart owing to its coordination favourability

Thermal, magnetic and electrochemical properties of polymeric copper complexes of 2-hydroxy-l,4-naphthoquinone and its methyl derivative

2563-2567The reaction of 2-hydroxy-l, 4-naphthoquinone (Lawsone;Lw) and 3-methyl-2-hydroxy-l, 4-naphthoquinone (Phthiocol;Phth) with anhydrous CuCl2 results in [Cu(Lw)2(NH3)2] (M-l) and [Cu(Phth)2(NH3)].2H2O (M-2) complexes respectively. Thermal, magnetostructural and electrochemical studies indicate the polymeric nature of both the complexes. The energy of activations calculated from the thermogramms is found to be 65 kJ/Lw, 23.75 kJ/NH3 in M-1 and 178.90 kJ/H2O, 221.5 kJ/NH3, 566.2 kJ/Phth and 28.19 kJ/Phth in M-2. The increasing and decreasing nature of χm.T with decrease in temperature in M-l and M-2 reveals the ferro and antiferromagnetic interactions in M-l and M-2 respectively. The cyclic voltammetry studies indicate occurrence of effective metal ligand interactions in solution for both the complexes

Synthesis and molecular structure of a zinc complex of the vitamin K3 analogue phthiocol

The complex [Zn(phthiocol)2(H2O)2]; 1, where phthiocol is 2-hydroxy-3-methyl-1,4-naphthoquinone, has been synthesized and characterized by elemental analysis, FT-IR, 1H NMR, UV–vis spectroscopy, thermogravimetric (TG) analysis, electrochemical and single crystal X-ray diffraction studies. The νCO stretch shifts to lower frequencies upon complexation of phthiocol to Zn2+. 1H NMR spectra show an upfield shift of the benzenoid ring protons in 1. There is a bathochromic shift of the LMCT band in the UV–vis spectra of 1. Single crystal X-ray structure of 1 show distorted octahedral geometry around Zn2+. Two phthiocol ligands are in plane with the metal, while water molecules are trans to this plane. Coordination of deprotonated phthiocol ligands is ‘trans, trans’ to Zn2+. Intra as well as intermolecular interactions are observed in 1. Molecules of 1 show three dimensional network through CH⋯O and OH⋯O interactions. Additional anodic peaks are observed in cyclic voltammogram of phthiocol ligand due to oxidation of reduced species formed during reduction. One-electron reduction of 1 is shown to be reversible and DFT studies define this redox event as ligand-centered

Nonexponential relaxation of the metastable state of the spin-crossover system [Fe(L)<SUB>2</SUB>](ClO<SUB>4</SUB>)<SUB>2</SUB>&#183;H<SUB>2</SUB>O [L = 2,6-Bis(pyrazol-1-ylmethyl)pyridine]

The relaxation of the metastable state of the spin-crossover compound [Fe(L)2](ClO4)2&#183;H2O, with L = 2,6-bis(pyrazol-1-ylmethyl)pyridine, populated by the LIESST (light induced excited spin state trapping) effect, has been investigated by magnetic measurements. The time dependence of the relaxation curve at several temperatures, starting from different initial states, is in the shape of stretched exponentials, and the thermal variation of the photostationary state under constant photoexcitation is progressive and reversible. These features are satisfactorily modeled by considering noninteracting two-level systems with a distribution of activation energies. A suggested origin for the distribution is the conformational flexibility of the nonplanar heterocyclic ligands. The effect of the intensity distribution during the LIESST process is also accounted for in a simple way