The complexes of silver nitrate and nitrite with organic nitriles show very good antimicrobial and antifungal properties, connected with the facile release of silver ions. Along with the antimicrobial activity, interesting electrical phenomena related to the electronic structure of organic ligands have been observed.

In the present study, the structure, thermal stability, conductive properties, and antimicrobial activity of silver(I) complexes with nitrile ligands were investigated. For the construction of the materials, 2-cyanopyridine (2-cpy), 4-cyanopyridine (4-cpy), 1,2-dicyanobenzene (1,2-dcb), and 1,3-dicyanobenzene (1,3-dcb) were used in addition to the silver nitrite and nitrate. Four new compounds were isolated and structurally characterized: one molecular complex [Ag₄(1,2-dcb)₄(NO₃)₄], two 1-D coordination polymers [Ag(2-cpy)₂(NO₂)]_∞, [Ag₂(1,3-dcb)₂(NO₃)₂]_∞, and one 3-D coordination polymer [Ag(4-cpy)(NO₂)]_∞. The results indicate that the nitrile complexes display good antimicrobial properties against the tested bacterial and fungal strains. The presence of weakly coordinating CN groups increases the release of silver ions into the bacterial and yeast cell environments. Moreover, these materials exhibit unusual electrical properties in thin-layer devices. On the other hand, the nitrite and nitrate counterions give rise to the low thermal stability of the complexes.

Acetate-bridged Co(II) and Ni(II) complexes, [Co(L)(μ-OAc)(EtOH)] (1) and [Co(L)(μ-OAc)(EtOH)] (2) were synthesized by reacting the bis(salamo)-like ligand with two different metal(II) acetates. The ratio of the ligand and metal(II) ions in the solid and liquid phases of the complexes was determined by X-ray single crystal diffraction and UV–vis spectral titration, and the uniqueness of the solid–liquid two-phase substance was determined.

Acetate-bridged binuclear Co(II) and Ni(II) complexes, [Co₂(L)(μ-OAc)(EtOH)] (1) and [Ni₂(L)(μ-OAc)(EtOH)] (2) were synthesized via the reaction of a new bis(salamo)-like ligand with two different metal(II) acetates. X-ray single crystal diffraction analyses showed that two metal(II) ions (Co or Ni) occupy two sets of N₂O₂ cavities, respectively. The acetate group bridges the two metals, and the ethanol oxygen atom participates in the coordination. Furthermore, UV–vis titration experiments clearly indicated that the complexation between H₃L and M(II) ions leads to the 1:2 complexes [(L)M₂]⁺ through a highly synergistic process. Bond valence sum (BVS) calculations exhibited that the Co(II) and Ni(II) ions are divalent. Secondly, the ligand H₃L highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO-LUMO) gap analysis and surface electrostatic potential were theoretically analyzed by theoretical calculation (density functional theory), and the reactivity of M(II) ions and the ligand in the complex formation process was demonstrated. Finally, the microscopic properties of the complexes were deeply understood through the calculation of the weak intramolecular interactions and the unstressed regions outside the complexes.

The current research describes the synthesis of a unique series of mixed ligand complexes of Cr(III), Fe(III), Ni(II), Mn(II), Cu(II), Co(II), Zn(II), and Cd(II) produced from BHX (1ry ligand) and 1,10-phenanthroline (Phen; 2ry ligand) and distinguished by spectral. The two ligands' potential for coordination with metal ions has been suggested by chemical analysis and spectral (¹H-nuclear magnetic resonance, ultraviolet-visible, and mass spectrometry) and thermal studies. BHX and Phen are neutrally bidentately coupled to the metal ions.

The medication bromhexine (BHX) is well-known for its unique properties and therapeutic advantages, with prospective uses in the prevention and treatment of cancer growth and bacterial infections. The current research describes the synthesis of a unique series of mixed ligand complexes of Cr(III), Fe(III), Ni(II), Mn(II), Cu(II), Co(II), Zn(II), and Cd(II) produced from BHX (1ry ligand) and 1,10-phenanthroline (Phen; 2ry ligand) and distinguished by spectral. The two ligands' potential for coordination with metal ions has been suggested in view of chemical analysis and spectral (¹H-nuclear magnetic resonance, ultraviolet–visible, and mass spectrometry) and thermal studies. BHX and Phen are neutrally bidentately coupled to the metal ions, according to infrared spectral study. The general formula of [M(BHX)(Phen)(H₂O)_n.Cl_m] was suggested using the molar conductivity, elemental analyses, and thermal information of the complexes that were produced. Where M = Fe(III) (n = y = 2, m = 0, and x = 3), Co(II) (n = x = 2, m = 0, and y = 3), Ni(II) (n = x = 2, m = 0, and y = 6), and Cd(II) (n = x = y = 2 and m = 0) with an octahedral geometry was proposed. Thermal analyses revealed that the complexes lost anionic part and organic ligands in continual changes after first losing water molecules of hydration. Compared with their parent BHX ligand, the mixed ligand complexes demonstrated promising microbiological activities against a variety of bacterial species, including Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). According to the results, mixed ligand complexes are more efficient than the parent BHX and Phen ligands. The complexes moderately inhibit the development of the MCF-7 antibreast cancer cell line. The chemistry of the linking energy, H-bond, and hydrophobic interactions of the BHX ligand and its mixed Cu(II) complex with Phen are revealed by molecular docking investigations with the crystal structure of S. aureus nucleoside (PDB: 3Q8U) and human prostate-specific antigen (PDB: 3QUM).

Molybdenum (VI) complex of resorcinol-based ligand immobilized on silica-coated magnetic nanoparticles was prepared. The catalyst was characterized with analytical techniques such as FT-IR, SEM, TEM, XRD, XPS, VSM, ICP, EDX, NH3-TPD, and TGA. This novel catalyst with acidic and basic sites was used in (trans)esterification reaction for biodiesel production of rapeseed, soybean, and sunflower and used frying oils under mild reaction conditions with easy reusability, high activity, and selectivity with acidic and basic sites.

Reusability and durability of catalysts are main factors in biodiesel production. Fe₃O₄@SiO₂-APTES-MoO₂L₂ ^DHAPh catalyst was prepared in five steps. At first, Fe₃O₄ was synthesized and coated with silica (Fe₃O₄@SiO₂). After that, the nanoparticles were functionalized by APTES (Fe₃O₄@SiO₂-APTES). In following, DHAPh ligand was anchored covalently onto the surface of aminated magnetic nanoparticles (Fe₃O₄@SiO₂-APTES-L^DHAPh), and at the end, DHAPh ligand was metalled by MoO₂(acac)₂ salt (Fe₃O₄@SiO₂-APTES-MoO₂L₂ ^DHAPh). The catalyst was characterized with analytical techniques such as FT-IR, SEM, TEM, XRD, XPS, VSM, ICP, EDX, NH₃-TPD, and TGA. This novel catalyst with acidic and basic sites was used in (trans)esterification reaction for biodiesel production of rapeseed and other oils. The biodiesel yield of rapeseed, soybean, sunflower, and used frying oils was attained 97%, 98%, 96%, and 87%, respectively, under optimized reaction conditions, such as 0.1 mol% amount of catalyst, 0.05 mmol KOH as methanol activator, a short reaction time of 2 h, and methanol to oil ratio of 3:1 at room temperature. The conversion of oil to methyl ester biodiesel was confirmed by FT-IR, ¹H NMR, and GC-MS analysis. The leaching and reusability tests of the prepared catalyst were checked, which displayed the biodiesel production proceeded via a heterogeneous pathway. Also, this catalyst can be reused for 11 cycles without tangible loss in its catalytic activity. The mentioned heterogeneously homogenized nanocatalyst has the main benefits such as easy reusability, high activity, and selectivity with acidic and basic sites that makes it a potential candidate for both esterification and (trans)esterification of low quality feedstock for low cost biodiesel production.

Iron tethered carbon nitride has been developed and utilized as a recoverable heterogeneous catalyst for the construction of bis (hetero/homoarylidene)cycloalkanones in water, an environmentally nonthreatening medium at ambient temperature.

Iron integrated graphitic carbon nitride (GCN) was synthesized by adopting co-precipitation method. No appreciable change in XRD main peak of both GCN and Fe(III)-GCN indicates the lattice structure remains the same and there is no bulk doping of Fe(III). More sharp IR bands of Fe(III)-GCN between 1000 and 1750 cm⁻¹ compared with GCN reflect ordered packing of tri-s-triazine units in the nanosheets. Scanning electron microscopy (SEM) analysis reveals less thin and large two dimensional sheets have formed from bulk GCN during catalyst preparation. The absence of bright spots in transmission electron microscopy (TEM) indicates that there is no crystalline metal oxide phase confirming that iron(III) is present as ions. Fe(III)-GCN was then exploited as an efficient heterogeneous catalyst for the synthesis of bis (hetero/homoarylidene)cycloalkanones from heteroaromatic/homoaromatic carbaldehydes and cycloalkanone through carbon–carbon double bond construction. The reaction effected well in water, a green solvent as a reaction medium at ambient temperature. The catalytic competency exposed good performance towards reusability. Added advantages include easy preparation and inexpensiveness.

A new dendrimer containing ferrocene units is used as an efficient combustion catalyst for ammonium perchlorate-based propellant.

Ferrocene-based compounds are promising burning rate catalysts due to their attractive catalytic activity, flammability, and non-toxic performance. Unfortunately, the high-migration issue of the ferrocene-based catalysts makes it challenging to store composite solid propellants for a long time. Therefore, a dendrimer containing ferrocene units with anti-migration ability was designed herein. The introduction of polar groups provides a large number of interaction sites for anti-migration, and no migration of the dendrimer in the propellant was observed after 4 weeks of the aging test. For catalytic performance, the results showed that the thermal decomposition temperature of ammonium perchlorate could be reduced from 404°C to 369°C by adding 3 wt% ferrocene-based dendrimer. Moreover, compared with the propellant mixed with Catocene, the propellant containing ferrocene-based dendrimer showed a lower pressure exponent (0.47) and a higher burning rate (2.03 mm·s⁻¹, at 0.1 MPa).

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).