A new set of Pd(II) O^N^O pincer complexes is synthesized and characterized. Further, the solid-state molecular structures of the complexes have been well authenticated by single-crystal XRD studies. The catalytic efficacy of complexes has been explored towards N-alkylation of benzamides/sulfonamides using aromatic primary alcohols through borrowing hydrogen strategy.

The development of green, sustainable, and atom-economical procedure for the construction of amides via C-N bond formation is a high priority in synthetic organic community. In this research article, we demonstrate a simple and an efficient catalytic protocol for N-alkylation of benzamides/sulfonamides using aromatic primary alcohols as coupling partners through borrowing hydrogen (BH) strategy by employing newly constructed palladium (II) O^N^O pincer complexes. All the palladium complexes are characterized by analytical and spectral methods (FT-IR, NMR, and HRMS). Further, the solid-state molecular structures of the complexes have been well authenticated by single-crystal XRD studies. The present N-alkylation protocol is facile, worked in low catalyst loading (0.5 mol%), and furnishes the desired N-alkyl amides with excellent yields up to 92%. In this methodology, the reaction proceeds via the formation of intermediates such as aldehyde and (E)-N-benzylidenebenzamide with a release of water as ecological by-product. The control experiments and plausible mechanistic investigations suggested that the coupling reaction was initially proceeds via dehydrogenation of alcohol and generate the alkylated products through hydrogen auto-transfer. A large-scale synthesis of N-(4-methoxybenzyl)benzamide proves the effectiveness of the Pd (II) pincer catalysts.

The reaction of ethyl isothiocyanate with Girard's T affords a new hydrazone named 2-(2-N,N,N-trimethyl-2-oxoethane-1-auminium chloride [EtGT]). Its structure was confirmed by single crystal X-ray diffraction. Also, the isolations and characterizations of new metal complexes with EtGT were confirmed by elemental analyses, IR, UV-visible, magnetic measurements, ¹³C-NMR, ¹H-NMR, and thermal analyses. IR spectra suggest that the ligand acts as a bidentate coordinating either via the carbonyl oxygen and the nitrogen atom of the hydrazine group or through the sulfur (C=S and/or C-S) and the NH groups. The computational estimation of EtGT and its complexes were approved with the Gaussian 09 W program in DFT/B3LYP. DPPH and ABTS are two free radical scavenger tests that were utilized in order to evaluate the antioxidant potential of complexes in vitro. Furthermore, the biological effectiveness of the ligand and its complexes against bacteria varieties Gram (₊ve) and Gram (−ve) bacteria was in vitro investigated. Also, antifungal action was investigated utilizing inhibition zone diameter. Moreover, the ligand and its complexes also exhibited a broad spectrum of DNA degradation effects, as measured by agarose gel electrophoresis. Cyclic voltammetry of Co²⁺ with different concentrations was measured experimentally. Molecular docking is exercised to examine the inhibitor characteristics of complexes through binding propensity with CTX-M-14 β -lactamase (Class A).

A novel 1,3-diphenyl-4-(N,N-dimethylimidodicarbonimidic diamide azo)-5-pyrazolone and its complexes were prepared and recognized using different techniques. The geometrical and nonlinear optical parameters of the ligand and its complexes were modeled theoretically using density functional theory (DFT) at the B3LYP level of theory employing the 6-311G** basis set for C-, H-, N-, and O-atoms and LANL2DZ basis set for the metal atoms. The electronic transitions were computed by time-dependent DFT (TD-DFT/PCM) with the B3LYP method using a 6-31G(d,p) basis set. The prepared free ligand's antibacterial activity and solid chelates were also experimentally evaluated against Gram-negative bacteria and Gram-positive bacteria. The molecular docking mechanism between the bacterially resistant complexes and their inhibited bacteria protein pocket receptors was carried out to determine the binding modes of these compounds at their active sites.

A novel 1,3-diphenyl-4-(N,N-dimethylimidodicarbonimidic diamide azo)-5-pyrazolone as a ligand, simplified as DNP, and its chelates were prepared. Characterization of the structures was performed based on several analytical and spectroscopic techniques. To support these studies, density functional theory (DFT) calculations were carried out by using the B3LYP level, B3LYP/6-311G** level for the free ligand, and B3LYP/6-311G**-LANL2DZ functional level for the solid chelates. The acquired results indicated that DFT calculations generally give compatible results with the experimental ones. Hyper conjugative interactions, molecular stability, bond strength, and intramolecular charge transfer were examined by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of the obtained compounds were investigated by determining molecular polarizability (α), and hyperpolarizability (β) parameters provided a hint for the synthesized compounds' intriguing optical characteristics. The electronic structure of the ligand and its complexes were predicted using the time-dependent DFT (TD-DFT) method with a polarizable continuum model (PCM) exploiting the B3LYP approach combined with a 6-31G(d,p) basis set. The prepared compounds' antibacterial activity was experimentally verified utilizing the agar well diffusion method versus selected G + and G- bacteria. The molecular docking mechanism between the bacterially resistant chelates and their inhibited bacteria protein pocket receptors was carried out to determine the modes that these compounds bind to the protein's active sites.

Novel azo dye containing the heterocyclic quinaldine nucleus and its Co(II), Ni(II), and Zr(IV) nanocomplexes have been synthesized and fully characterized by experimental and theoretical methods. Their antibacterial and antitumor activities were tested. The cytotoxic efficiency of both Co(II) and Ni(II) complexes exceeded that of vinblastine. The interactions between Zr complex and PANC-1 were then investigated using molecular docking. Also, their catalytic efficacy was tested on the oxidative degradation of methyl violet 2B dye in the presence of H₂O₂.

Novel azo dye containing the heterocyclic quinaldine nucleus, 3-((2-methylquinolin-4-yl)diazenyl)naphthalen-2-ol HL, and its Co(II), Ni(II) and Zr(IV) nano-sized metal chelates have been synthesized and fully characterized by alternative analytical and spectral techniques. The finding indicated that the ligand coordinated as a monobasic bidentate via azo nitrogen and hydroxyl oxygen atom, resulting in octahedral geometry towards Co(II) and Zr(IV) complexes, and square planer geometry towards Ni(II) metal ion. Theoretical studies by DFT/B3LYP/6-311+G(d,p)/LANLDZ including energetic parameters, geometrical optimization, dipole moment, and HOMO–LUMO energy gap were applied to support the geometrical arrangement of the complexes. The produced complexes were generated at the nanoscale, as evidenced by the average particle size from TEM. The average particle size calculated from TEM images for Co(II), Ni(II), and Zr(IV) complexes is 6.0, 12.0, and 5.5 nm, respectively. The antibacterial activity of the ligand compared with its metal complexes shows enhanced activity over the metal complexes against different types of bacteria. Antitumor efficacy of the compounds was tested against A-549 and PANC-1 cells, compared with the vinblastine standard. The cytotoxic efficiency of both Co(II) and Ni(II) complexes exceeded that of vinblastine. The anticancer activity of the Zr complex was then studied using molecular docking to determine the interactions between this molecule and PANC-1. Docking studies revealed that the Zr complex produces four hydrogen bond contacts with the active amino acid residues Arg 136 and Asp 140, two hydrophobic interactions with Val 50 and Leu 147, and two electrostatic interactions with Arg 136. Also, the catalytic property of the free ligand and nanocomplexes were tested on the oxidative degradation of methyl violet 2B dye in the presence of H₂O₂. The following arrangement was observed for the pseudo-first-order rate constants: Co(II) complex (0.068 min⁻¹) > Ni(II) complex (0.066 min⁻¹) > Zr(IV) complex (0.061 min⁻¹) > HL (0.037 min⁻¹).

An efficient ambient-temperature synthetic approach is presented for surface functionalization of waste shrimp shells using 3-(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (DMPZ-Tz) via nucleophilic substitution with 3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (BDMPZ-Tz). The modified shrimp shells serve as a catalyst support for ruthenium-embedded transfer hydrogenation catalysts, employing ethanol as the hydrogen source and potassium carbonate as the base.

Sustainable chemical research emphasizes chitosan-based catalysts and the need to explore the direct utilization of waste shrimp shells, whereas the use of ethanol as a hydrogen source in transfer hydrogenation is less explored due to its unfavorable redox potential, higher energy barriers, generation of reactive intermediates, and catalyst poising via metal carbonyl species or decarbonylation. Herein, we disclosed an efficient synthetic approach, conducted at ambient temperature, for surface functionalization of waste shrimp shells with 3-(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (DMPZ-Tz) via nucleophilic substitution using 3,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,2,4,5-tetrazine (BDMPZ-Tz). This method results in a color change and a 75% increase in surface nitrogen content, eliminating the need for multiple syntheses and harsh reaction conditions. We utilized the strong coordination property between DMPZ-Tz and [Ru(p-cym)Cl₂]₂/RuCl₃.3H₂O to develop ruthenium-embedded transfer hydrogenation catalysts supported on shrimp shells. These catalysts were employed for the selective transfer hydrogenation of unsaturated carbonyl/aldehydes to saturated carbonyl/alcohols, utilizing ethanol as the hydrogen source and potassium carbonate as the base. The performance, selectivity, and reusability of the catalyst were thoroughly assessed through spectroscopic studies, in-situ monitoring of the reaction progress, initial rate kinetics, and control experiments. The obtained results strongly indicated that the anchoring of DMPZ-Tz played a crucial role in achieving superior performance compared with catalysts synthesized without it or utilizing its homogeneous counterparts. The catalyst exhibits efficient reactivity, selectivity, and broad substrate scope.

AuCo bimetallic nanoparticles were supported on magnetic crosslinked copoly(ionic liquid) nanohydrogel and resulting material applied as an efficient recyclable catalyst in reduction reactions.

Synergistic effects in bimetallic catalysts produce a catalyst with superior activity than a monometallic component. In this work, a novel magnetic crosslinked copoly(ionic liquid) nanohydrogel was synthesized and employed for the stabilization of AuCo bimetallic nanoparticles (Fe₃O₄@PolyIL-AuCo). This material was characterized using different instrumental techniques such as FT-IR, TGA, XPS, VSM, solid-state UV–Vis, SEM mapping, and TEM. Results indicated a narrow size distribution of nanoparticles and high water dispersibility of Fe₃O₄@PolyIL-AuCo. Using this catalyst, a series of nitroarenes were reduced to the corresponding amines in aqueous media. In addition, organic dyes were efficiently degraded by this catalyst. Different experiments dealing with the same transformation confirmed that Fe₃O₄@PolyIL-AuCo exhibited higher catalytic activity than the similar monometallic Au and Co catalysts. This catalyst was recycled for at least 11 consecutive runs with very small deactivation, and TEM, VSM, and XPS confirmed the stability of the reused catalyst.