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Recent advances in industrial catalysis are very important for the development of effective and efficient catalysts and catalytic methods. The review largely focuses on immobilization techniques that have been utilized for metal complexes, usually mesoporous materials such as silica, alumina, and zeolite. The supported catalysts have a wider range of catalytic applications than their neat or homogeneous counterparts. The active metal compound may be retained on the solid support by adsorption, ion exchange, encapsulation, or the formation of a covalent bond between the metal–ligand and the solid support. The supported complexes are used as catalysts for organic transformation reactions, such as oxidation and functionalization of organic compounds.

In this study, biopolymer composites based on chitosan (CS) with enhanced optical properties were functionalized using Manganese metal complexes and black tea solution dyes. The results indicate that CS with Mn 2+ -complexes can produce polymer hybrids with high absorption, high refractive index and controlled optical band gaps, with a significant reduction from 6.24 eV to 1.21 eV. The refractive index and optical dielectric constant measurements show that the doped CS films have more charge carriers and traps than those in pure CS films. The Lorentz-Drude model was used to derive several significant optical parameters, and the W-D model was utilized to calculate the optical moments M -1 changing from 0.35 to 2.13 and M -3 changing from 0.005 to 0.4. It was shown that the doped samples have larger Urbach energy than pure film, increased from 0.29 to 0.55 eV. Tauc and ASF model was also used to calculate the electronic transitions, band structure, and optical characteristics. Bandgap energy based on Tauc model at m = 2, 1/3, 1/2, and 2/3 are 1.77, 1.54, 1.47, and 1.37 eV, based on ASF model are 1.52, 1.42, 1.69, and 1.47 eV, respectively. As a result of changes in the optical diffraction parameters the optical mobility ( ) changed from 1.67 to 1.27 and optical resistivity from 9.36 × 10 –27 to 4.0 × 10 –29 . The dopped samples show an increase in their linear optical susceptibility, third-order nonlinear optical susceptibility and nonlinear refractive indices, changing from 3.165 × 10 –15 to 2.831 × 10 –12 esu. Finally, light propagation velocities, surface resistance, and thermal emissivity were also examined.

The current study used sustainable and green approaches to convey polymer composites with desired optical properties. The extracted green tea dye (GTD) enriched with ligands was used to synthesize zinc metal complexes. Green chitosan biopolymer incorporated with green synthesized metal complex using casting technique was used to deliver polymer composites with improved optical properties. The FTIR-ATR was used to identify the functional groups of the GTD, pure CS, and functional groups surrounding the synthesized zinc metal complex. Distinguished ATR bands were observed in green tea dye spectra, such as OH, C = O, and NH functional groups ascribed to various polyphenols. The ATR bands of the zinc metal complex compared to GDT established that GDT is crucial to capturing zinc cations and producing the Zn 2+ -metal complex. The broadness of the bands observed in CS-based composites inserted with the Zn 2+ - metal complex confirms strong interaction among the components of polymer composites. The XRD achievements confirm that CS films with different Zn2+- metal complex concentrations transferred to an amorphous composite. The XRD pattern of composite films establishes that the zinc metal complex scarified the crystalline phases of chitosan. Linear optical properties such as absorption, refractive index (n), and optical dielectric parameters were improved. The absorption edge of the composite’s films shifted to lower photon energies. Various models were used to determine the optical band gap. The band gap drops from when chitosan is loaded with a 36% Zn 2+ -metal complex. The Spitzer-Fan method is used to get the dielectric constant, and the Drude Lorentz oscillator model was used to calculate vital optical parameters, including N/m* , τ , and µ opt . The W-D single oscillator model was used to determine the E o and E d parameters. The values of optical moments ( M −1 and M −3 ) were calculated with the help of the W-D model. The oscillator’s strength ( ) and wavelength ( ) were determined via the Sellmeier model using the linear refractive index. The first-order nonlinear ( ), second-order non-linear ( ) and third-order nonlinear optical susceptibility ( ) were determined for all the films.

Photoactive complexes of nonprecious transition metals, mainly including those in the first-row and partially the second-row of the Periodic table of elements, have received increasing attention in view of their low cost and long-term sustainability. They are recognized as promising alternatives to noble transition metal complex congeners that have been extensively studied in optoelectronic devices, artificial photosynthesis, photocatalysis, biodiagnostics, and therapeutics, etc. This review is devoted to a comprehensive summary on the classical and recent advances on photoactive nonprecious transition metal complexes, including photoactive Zr, V, Cr, Mo, and W complexes, Mn complexes and hybrids, Fe, Co, Ni, and Cu complexes, and Zn and Cd complexes and hybrids. A particular focus is given on the molecular design, modulation of photophysical and photochemical properties, and applications of the representative and lately-developed nonprecious metal complexes. In addition, a perspective on the future development in this field is provided at the end of this review.

Schiff bases transition metal complexes have received significant attentions in the scientific community for their versatile applications. The incorporation of metals to Schiff base ligands attracts much attention, since the metals and Schiff base ligands coordinated via bonding. Thus, chelation effects will enhance and improve the biological activities of the derivatives of title compound. Most of these derivatives displayed broad range bioactivities including antibacterial, antifungal, antituberclosis, antimalarial, antioxidant, antidiabetic, anti-inflammatory and anticancer activities. Up to date, continuous efforts are being made in various research groups to design the outcomes of more potent, novel and safe synthetic protocols towards the Schiff base metal complexes. Therefore, this review summarizes the various synthetic protocols and pharmacological activities of Schiff base metal complexes and their derivatives. Here, the synthesis of Schiff base ligands and their complexes with metals Cu(II), Pt(II), Ni(II), Pd(II), Ru(II, III), V(III), Cd (II), Zn(II), Co(II, III) and Mn(II, III) will be presented ( 2013–2022 ).

The chemistry of transition‐metal (TM) complexes with monoanionic bidentate (κ2‐L,Si) silyl ligands has considerably grown in recent years. This work summarizes the advances in the chemistry of TM‐(κ2‐L,Si) complexes (L=N‐heterocycle, phosphine, N‐heterocyclic carbene, thioether, ester, silylether or tetrylene). The most common synthetic method has been the oxidative addition of the Si−H bond to the metal center assisted by the coordination of L. The metal silicon bond distances in TM‐(κ2‐L,Si) complexes are in the range of metal‐silyl bond distances. TM‐(κ2‐L,Si) complexes have proven to be effective catalysts for hydrosilylation and/or hydrogenation of unsaturated molecules among other processes. This work summarizes the advances in the chemistry of transition metal complexes with monoanionic bidentate ligands κ2‐L,Si (L=N‐heterocycle, phosphine, N‐heterocyclic carbene, thioether, ester, silylether or tetrylene).

The Schiff base metal complexes containing the transition metal ions Co(II), Ni(II) and Cu(II) were synthesized using their nitrate and acetate salts. An octahedral environment encircling metal complexes has been demonstrated by the findings of multiple spectroscopic approaches that were employed to demonstrate the structure of the metal complexes. The Coats–Redfern method of thermal analysis was employed to carry out the kinetic and thermodynamic calculations. The crystalline size of ligand was 36.67 nm and for the metal complexes it varies from 22.43 to 49.21 nm. To assess the biological effectiveness of these compounds, molecular docking studies were emanated. The docking binding studies were established through the interaction of metal complexes with human cancer protein, such as 3W2S (ovarian cancer) and 4ZVM (breast cancer). The results exemplified that the complexes are more efficient towards ovarian cancer (3W2S) in contrast to breast cancer (4ZVM) while among complexes, the nickel acetate (− 7.0 kcal/mol) and copper acetate (− 7.9 kcal/mol) complex were more efficient towards 4ZVM and 3W2S receptors respectively. Additionally, DNA binding studies against 1BNA receptor protein was examined from docking evaluations and the finding concludes the highest efficiency of nickel (− 8.1 kcal/mol) complexes. Further, a number of bacterial and fungal strains have been implemented in antimicrobial examinations to assess the compounds effectualness. The results untangled the extreme potential of copper nitrate (0.0051–0.0102 µmol/mL) and copper acetate (0.0051–0.0103 µmol/mL) complexes against all bacterial and fungal strains except for S. aureus in which nickel acetate proved out to be highly competent. Graphical abstract

This study aims to synthesize and characterize a series of mononuclear and mixed metal diethyldithiocarbamate complexes containing Ag(I), Cu(II), Mn(II), and selenium ions, and to explore their structural, optical, electrical, and thermal properties. These complexes are of considerable interest because metal dithiocarbamates can serve as versatile single-source precursors for the fabrication of semiconductor materials and other advanced functional systems. The synthesized complexes were characterized using XRD, elemental analysis (SEM–EDX), spectroscopy techniques (IR, NMR, UV–Vis, ESR, and fluorescence), magnetic measurements, density functional theory (DFT), and thermal analyses (TGA, DTA, DSC). Structural investigations confirmed the ability of diethyldithiocarbamate ligands to form multinuclear coordination assemblies with the investigated metal ions, producing sponge-like structures. The UV–visible spectra showed strong absorption at 240–435 nm and high transmission (84%-99%) around 300 nm, with an optical band gap between 1.95 and 4.15 eV. The oscillator and the dispersion energies of linear refractive index ( n ) were evaluated using the Wemple Di-Domenico single oscillator model. The emission spectra exhibited three fluorescence peaks in the range 427–531 nm. The dielectric characteristics and alternating current conductivity (σ ω ) were measured at temperatures ranging from 298 to 400 K and frequencies between 120 Hz and 100 kHz. The electrical measurements of the samples revealed semiconducting behavior with σ ω values of 10 –7 –10 –1 S/m, and E a of 0.035–2.71 eV. Various conduction mechanisms were observed with increasing temperature, as evidenced by changes in the dielectric parameters. Thermal analyses emphasized that complexes may be applied for the synthesis of nanoscale metal sulfides with semiconductor properties.

Condensation of 2,3-diaminopyridine with 2,4-dihyrodybenzaldehyde yielded a 4,4’-[(1E,1 ~ E)-(pyridine-2,3-diyl)bis(azanylylidene)]bis(methanylylidene)bis(benzene-1,3-diol) monobasic tridentate Schiff base ligand (HL) with an ONN donor sequence. Elemental analyses, conductivity tests, magnetic susceptibility data, FT-IR, UV–vis spectra, x-ray diffraction, and mass spectrum data of the ligand and its complexes were used for the characterization of the structures. Computational HF/3-21G calculations were performed to optimize their geometrical structures and assess their HOMO–LUMO energy gaps. The low molar conductance of the complexes indicates that they are not electrolytic. From the spectrophotometric and gravimetric analyses, the complexes (2–4) are in the ratio of 1:2, while complexes (1 & 5) (1:1) metal to ligand. 2,3-Diaminopyridine, 2,4-dihydroxybenzaldehyde, ligand (HL) and its complexes were screened for antibacterial and antifungal activities against some bacterial ( Enterococcus faecalis , Salmonella typhi , and Staphylococcus epidermidis ) and fungal isolates ( Aspergillus flavus , Alternaria solani , and Candida albicans ). The result reveals that 2,4-dihyrodybenzaldehyde has the strongest antibacterial activity among the other compounds followed by Mn(II) complex. The antimicrobial activity increases by increasing the compound concentration. To assess the inhibitory impact of ligand and its complexes on binding sites of B. cereus (PDB ID: 1FEZ), S. epidermidis (PDB ID: 3KP7), E. faecalis (PDB ID: 5V5U) and S. typhi (PDB ID: 5V2W) proteins, molecular modeling has been implemented offer a fresh concept for medication design. Molecular docking studies confirmed strong binding interactions between the metal complexes and bacterial proteins, validating their biological potential. These findings demonstrate the promising antimicrobial properties of Schiff base metal complexes, making them potential candidates for pharmaceutical and medicinal applications.

In this study breakthrough methodology has been used to deliver advanced polymer composites based on polyvinyl alcohol (PVA) integrated with green-synthesized nickel metal complex (NiMC), utilizing a simple casting methodology. The structural and optical characteristics of PVA composite films were studied using XRD, FTIR, and UV-Vis spectroscopy, respectively. Band shifting in FTIR spectra and broadening of sharp peak in PVA composites compared to pure PVA establish strong interaction between NiMC and PVA functional groups. The surface of the films was examined for roughness and phase separation using FESEM investigation. Various optical models were employed to determine the optical band gap (E g ). The E g decreased from 6.05 eV to 1.69 eV for direct and 1.21 eV for indirect transitions. The increase in Urbach energy from 0.28 to 0.62 eV was correlated with XRD results. The oscillator energy parameters were determined from the empirical Wemple-DiDomenico model. The real and imaginary dielectric constants, volume and surface energy loss functions, optical density, 3rd order susceptibility X (3) , nonlinear refractive index n (2) and skin depth was studied in detail. Optical oscillator strengths( f ), optical moments M − 1 and, and interband strength M − 3 were also determined. The ( J ) and figure of merit (φ) versus hv were used to specify the photons that are capable to electron transfer from HOMO to LOMO orbitals. The optoelectronic parameters, including (N/M * ), t , ( w p ), ( u opt ), ( P opt ), the average interband oscillator wavelength, and average oscillator strength( S o ), were also determined for all the films.