Ligand HL Research Articles

Graphene oxide-supported molybdenum complex as catalyst for peroxidase and catechol oxidase-like reactions

In this study, we synthesized a molybdenum complex, [MoO2(L)(H2O)] (1), utilizing a Schiff base ligand H2L (I), which was formed by reacting 3,5-di-tert-butyl-2-hydroxybenzaldehyde with the mono hydrazide of terephthalic ester in a methanolic solution. This complex was subsequently immobilized on a functionalized graphene oxide surface (APTES@GO), prepared using 3-aminopropyltriethoxysilane (APTES) and graphene oxide (GO), yielding the supported complex [MoO2(L)(H2O)]@APTES@GO (2). Both complexes were characterized through various analytical techniques, with single-crystal X-ray diffraction (SC-XRD) being specifically employed for complex 1. The catalytic activities of the homogeneous and heterogeneous complexes were assessed for their peroxidase-like and catechol oxidase-like functions, particularly in the oxidation of 3,3′-diaminobenzidine (DAB) and 3,5-di-tert-butylcatechol (3,5-DTBC) in the presence of hydrogen peroxide. Both complexes exhibited excellent catalytic efficiency (Kcat) and substrate binding affinity (KM), comparable to natural enzymes. Additionally, the supported complex demonstrated good reusability, maintaining its catalytic activity over five consecutive cycles.

Preparation and characterization of novel flame-retardant paint of substituted cyclodiphosph(V)azane sulfonomide and their Cu(II), Cd(II) metal complexes as new additives for exterior wood coating protection

The development of flame-retardant materials has become an important research direction. For the past dozen years, researchers have been exploring flame retardants with high flame-retardant efficiency, low toxicity, less smoke, or other excellent performance flame retardants. Therefore, this work aimed to synthesize new cyclodiphosph(V)azane derivatives and their Cu(II) and Cd(II) metal complexes and investigated their potential applications as high flame-retardant efficiency. Various techniques were used to characterize the prepared ligand H2L and its metal complexes, including elemental analyses, mass spectra, conductivity measurements, electronic spectral data UV–vis, FT-IR, 1H,13C-NMR, TGA, XRD, and molecular docking experiments studies were M. tuberculosis receptors (PDB ID: 5UHF) and the crystal structure of human topoisomerase II alpha (PDB ID: 4FM9). Wood-based paint was physically mixed with the ligand H2L and its metal complexes. The obtained results of mechanical characteristics of the dried paint layers were noticed to improve, such as gloss value, which ranged from 85 to 95, hardness 1.5–2.5 kg, adhesion 4B to 5B, and impact resistance, which improved from 1.3 to 2.5 J. Moreover, the obtained results of flame-retardant properties showed a significant retardant impact compared to the blank sample, such as ignitability, which includes the heat flux which increased from 10 to 25 kW/m2, and ignition time, ranging from 550 to 1200 s, respectively, and limiting oxygen index (LOI) (%) which has been increased from 21 to 130 compared with the plywood sample and sample blank. The ordering activity of the observed results was noticed that coated sample based on Cd(II) metal complexes > coated sample based on Cu(II) metal complexes of Cyclophosphazene ligand > coated sample based on phosphazene ligand H2L > coated sample without additives > uncoated sample. This efficiency may be attributed to (1) the H2L is an organophosphorus compound, which contains P, N, Cl, and aromatic six- and five-member ring, (2) Cu(II) and Cd(II) metal complexes characterized by high thermal stability, good stability, excellent performance flame retardants, and wide application.

Crystal structure, theoretical calculations, mechanoluminescence feature and antimicrobial activity based on a double-armed Salamo-type ligand and its trinuclear Cu(Ⅱ) complex

A double-armed salamo-type ligand H4L and its Cu(Ⅱ) complex have been designed and synthesized. The stoichiometric ratios of the prepared H4L and its Cu(Ⅱ) complex were structurally characterized by a variety of analytical and spectroscopic techniques, including elemental analysis, FT-IR, UV–visible, fluorescence spectroscopy, and X-ray crystal diffraction. The results showed that H4L is a linear molecule, while the Cu(Ⅱ) complex is a trinuclear structure with three copper atoms exhibiting different coordination modes due to varying coordination cavities and bridging atoms. The quantum chemical parameters and molecular structures of the H4L and the Cu(Ⅱ) complex have been theoretically calculated and studied. Using molecular electrostatic potential (MEP) and density functional theory (DFT) calculations to understand the selectivity of the H4L and the Cu(Ⅱ) complex chemistry and related reactions. Detailed energy level transitions of the H4L and the Cu(Ⅱ) complex can be determined through time-dependent density functional theory (TD-DFT) calculations. In studying the fluorescence properties of liquid and solid states, it was observed that increasing water content leads to the formation of excimer in both the H4L and its Cu(Ⅱ) complex, the ligand H4L shown good mechanoluminescence, but the Cu(Ⅱ) complex did not. We studied the antimicrobial effectiveness of the H4L and the Cu(Ⅱ) complex against E. coli., the Cu(Ⅱ) complex showed higher inhibition of the pathogenic microorganisms.

Synthesis and Structural Study of the Mixed Copper (II)/lanthanum (III) Complex with the Bicompartmental Ligand H2L = 2,2'-{propane-1,2-diyl bis[Nitrilomethylylidene ]}Bis(6-Methoxyphenol)

Synthesis and Structural Study of the Mixed Copper (II)/lanthanum (III) Complex with the Bicompartmental Ligand H2L = 2,2'-{propane-1,2-diyl bis[Nitrilomethylylidene ]}Bis(6-Methoxyphenol)

Synthesis and characterization of indazole derived Schiff base ligands and their metal complexes: Biological and computational studies

Indazoles represent one of the most important heterocycles in drug molecules. Therefore, in the pursuit of potent biological agents, a series of ligands (HL1-HL4) and their corresponding transition metal complexes [M(L1-L4)2(H2O)2] were synthesized by the condensation reaction of 6-aminoindazole with various derivatives of salicylaldehyde. Further, the compounds underwent characterization through several physicochemical (TGA, powder XRD, SEM, EDAX) and spectroscopic techniques (FT-IR, UV–Vis, NMR, mass spectrometry, ESR). These techniques suggested hexacoordinated stereochemistry of the metal complexes, where ligands chelate via oxygen atom of phenolic ring, azomethine nitrogen and oxygen atom of water molecules in 1:2 (M:L) molar ratio. The thermal stability of the complexes was demonstrated by thermal analysis revealing three step decompositions leaving behind metal oxide as an end residue. The surface morphology of the ligands was distinct from metal complexes as revealed by SEM analysis, while mapping images demonstrated the simultaneously existence of the elements. While, to ascertain the nature of the obtained compounds (crystalline or amorphous), powder X-ray investigation was conducted by utilizing a wavelength of 1.54 Å. The compound’s antioxidant potential was assessed through DPPH assays and anti-inflammatory activity was evaluated using BSA denaturation inhibition assay, while their antimicrobial potential was evaluated against six microbial strains (E. coli, S. aureus, P. aeruginosa, B. subtilis, C. albicans, A. niger) by serial dilution approach. The performed biological evaluations revealed that the complexes are more efficient in controlling infectious ailment in comparison of ligands. HL2 (2) and its Cu(II), Zn(II) complexes (11, 12) exhibited potent antimicrobial activity (MIC value: 0.0047, 0.0048 µmol/mL against B. subtilis) and potent anti-inflammatory efficacy (IC50 value: 6.7 ± 0.044, 6.9 ± 0.036 µM). All the complexes exhibited potent antioxidant activity and their is enhancement in the activity of Schiff base ligands upon complexation, complex (19) demonstrated the greatest activity with IC50 value 2.1 ± 0.059. Additionally, the ADMET score provided a robust indication of the compounds’ drug-like behaviour. Furthermore, the biological effectiveness of the highly microbial potent ligand HL2 (2) and its complexes (9–12) was demonstrated through computational studies. The binding studies exposed that complexes (11, 12) exhibited lowest binding energy at −7.8, −7.9 kcal/mol. While, DFT study emphasized that complex (12) exhibits the highest electrophilicity index value (6.359), suggesting its affinity for binding with biological molecules and also revealed that complexes exhibit greater potency compared to the ligands and could potentially be utilized as drugs for combatting pathogen-induced malformations.

A Phosphine-Oxide Cobalt(II) Complex and Its Catalytic Activity Studies toward Alcohol Dehydrogenation Triggered Direct Synthesis of Imines and Quinolines.

Herein, a new pincer-like amino phosphine donor ligand, H2L1, and its phosphine-oxide analog, H2L2, were synthesized. Subsequently, cobalt(II) complexes 1 and 2 were synthesized by the reaction of anhydrous Co(II)Cl2 with ligands H2L1 and H2L2, respectively. The ligands and complexes were fully characterized by various physicochemical and spectroscopic characterization techniques. Finally, the identity of the complexes 1 and 2 was confirmed by single crystal X-ray structure determination. The phosphine ligand containing complex 1 was converted to the phosphine oxide ligand containing complex 2 in air in acetonitrile solution. Both complexes 1 and 2 were investigated as precatalysts for alcohol dehydrogenation-triggered synthesis of imines in air. The phosphine-oxide complex 2 was more efficient than the phosphine complex 1. A wide array of alcohols and amines were successfully reacted in a mild condition to result in imines in good to excellent yields. Precatalyst 2 was also highly efficient for the synthesis of varieties of quinolines in air. As H2L2 in 2 has side arms that can be deprotonated, we investigated complex 2 for its base (KOtBu) promoted deprotonation events by various spectroscopic studies and DFT calculations. These studies have shown that mono deprotonation of the amine side arm attached to the pyridine is quite feasible, and deprotonation of complex 2 leads to a dearomatized pyridyl ring containing complex 2a. The mechanistic investigations of the catalytic reaction, by a combination of experimental and computational studies, have suggested that the dearomatized complex, 2a acted as an active catalyst. The reaction proceeded through the hydride transfer pathway. The activation barrier of this step was calculated to be 26.5 kcal/mol, which is quite consistent with the experimental reaction temperature under aerobic conditions. Although various pincer-like complexes are explored for such reactions, phosphine oxide ligand-containing complexes are still unexplored.

Zinc(II) coordination compound with N′-(pyridin-2-ylmethylene)nicotinohydrazide: Synthesis, crystal structure, computational and cytotoxicity studies

In this work, we report on the synthesis of a novel zinc(II) coordination compound [ZnL2] (1), which was readily obtained from the reaction of Zn(OAc)·2H2O and N′-(pyridin-2-ylmethylene)nicotinohydrazide (HL) in methanol. Recrystallization of 1 from dimethylformamide under ambient conditions allowed to produce yellow block-like crystals of 1·H2O. Complex 1·H2O was characterized by FT-IR and 1H NMR spectroscopy, while its optical properties were studied by UV–vis and spectrofluorimetry in methanol. The crystal structure of the title complex was revealed by single crystal X-ray diffraction and further explored in detail by the Hirshfeld surface analysis. Theoretical investigations based on the DFT calculations have also been applied to show the electronic properties of complex 1. The antitumor activities of the parent ligand HL and complex 1 were studied using Dalton's lymphoma malignant cancer model. Both compounds were found to induce concentration-dependent cytotoxicity and apoptotic cell death, leading to a decrease in cell viability, body weight, and tumor volume in mice with the superior activity of complex 1 over HL. Mice treated with complex 1 demonstrated an increase in life span with a survival period of 23 days. Finally, using a molecular docking approach, we have probed complex 1 to inhibit the recombinant mouse tumor-necrosis factor alpha (mTNF).

Synthesis and Crystal Structure Studies of a New Complex of Co (III)-Schiff Base Derivative Derived from Isonicotinohydrazide

A new Co(III) complex prepared by the reaction of N'–(1–(pyridin–2 yl)ethylidene) isonicotinohydrazide (H2L) with Co(II) ion is reported in this paper. The H2L ligand is structurally characterized by elemental analysis, NMR, and infrared spectroscopies. The mononuclear complex [Co(HL)2]·Cl·3H2O (1), is characterized by infrared spectroscopy, elemental analysis, conductance, magnetic room temperature measurement and single X-ray diffraction. The complex crystallizes in the monoclinic system with space group P21/c. The parameters of the unit cell are a = 9.6818(3) Å; b = 25.1587(6) Å; c = 11.5481(3) Å; β = 101.797(3) °; Z = 4; Rint = 0.0313 and wR(F2) = 0.0812. The asymmetric unit of the compound contains a discrete [Co(HL)2]+ cation one free chloride anion and three uncoordinated water molecules. In the discrete cation one Co3+ ion two organic ligand molecules are present. The coordination polyhedron around the Co3+ center is best described as a distorted octahedral with CoN4O2 chromophore. The crystal structure of the complex is stabilized by intramolecular and intermolecular hydrogen bonds.

Lanthanide complexes of monosubstituted Calix[4]arene-ligands: Synthesis, structures, and magnetic properties of [Ln2(L)2(MeOH)4] (Ln = La, Gd, Tb, Tm) (H3L = mono-O-propargyl-calix[4]arene)

The ability of the propargylated calix[4]arene ligand H3L (= 25-(2-propynyloxy)-26,27,28-trihydroxy-calix[4]arene) to bind lanthanide ions has been studied. The triply deprotonated ligand was found to support dinuclear neutral complexes of composition [Ln2L2(MeOH)4] (Ln= La (1), Gd (2), Tb (3), Tm (4)). Spectroscopic data for 1–4 as well as X-ray crystallographic analysis of single crystals of 1∙(MeOH)2 and 2∙(MeOH)2 reveal that two [LnL] entities dimerize via two phenolato groups to generate a centrosymmetric (MeOH)2O3Ln(μ-O)2LnO3(OHMe)2 core structure. The Ln3+ ions reside in a distorted mono-capped octahedral coordination environment. Squid magnetic measurements for the Gd3+ and Tb3+ complexes agree with the formulation as dinuclear compounds, and reveal the presence of very weak antiferromagnetic exchange interactions (J < 0.1 cm−1). The ability of the La3+ complex to react with azides in a click reaction is also demonstrated.

Synthesis, structure, and small molecule in situ modification effects on proton conduction properties of triazine‐based triscarboxylic acid complexe

In this study, we synthesized and characterized a new Co(II)‐based coordination polymer, denoted as {[Co(HL)(dpa)]·H2O}n (1), derived from the H3L ligand and dpa co‐ligand. Single crystal X‐ray diffraction revealed that 1 forms a two‐dimensional (2D) layer and a three‐dimensional (3D) supramolecular structure via hydrogen bonding interactions. Presence of carboxylic acid groups in 1 was confirmed by X‐ray crystallography, prompting investigation into its proton transport properties. Additionally, electrostatic potential surface and nucleophilic index analyses were conducted to simulate potential proton transfer pathways. Furthermore, we prepared nine modified encapsulated materials using 1 as the base material (SDA@1, APH@1, APY@1, TA@1, BA@1, DIC@1, IDZ@1, SCA@1, and TYD@1), and tested their proton conductivity and activation energy compared to pure Nafion membrane and 1, analyzing the influence of different small molecule structures on proton conductivity. Comparative analysis revealed that only SDA@1 exhibited enhanced proton conductivity and reduced activation energy at 303 K, with an improvement rate of 220.8%. We hope that the methods presented herein can provide valuable insights for the design and development of high‐performance proton‐conducting materials, as well as for the exploration of proton conduction mechanisms.

Effect of ruthenium(II) complexes on MDA-MB-231 cells and lifespan/tumor growth in gld-1mutant, Daf-16 TF and stress productive genes: A perspective study

Pincer type coumarin based N-substituted semicarbazone ligands HL1–4 and their corresponding ruthenium(II) complexes (1–4) were synthesized, analyzed and confirmed by various spectro analytical techniques. The molecular structure of the ligand HL3 and complex 3 was confirmed by single crystal X-ray diffraction analysis. The stoichiometry of complexes 1, 2 and 4 was confirmed by high resolution mass spectroscopy (HRMS). The binding affinity of the compounds with CT-DNA (Calf Thymus DNA) and BSA (Bovine Serum Albumin) was established by absorption and emission titration methods. The results of In vitro cytotoxicity showed the significant cytotoxic potential of the complexes against MDA-MB-231 cells (TNBC- Triple-negative breast cancer). Among the complexes, 1 and 4 have shown appreciable results. Further, antimigratory activity against the MDA-MB-231 cells was studied for the complexes 1 and 4. The percentage cell cycle arrest, apoptosis and necrosis were explored by flow cytometry. The in vivo anti-tumor activity of the complexes 1 and 4 using C. elegans as model organism was established by using the tumoral C. elegans strain JK1466 (gld-1(q485)), which bears a mutation in the gld-1 tumor suppressor gene. We have determined the effect of our complexes on tumor gonad reduction and found to be non toxic to the JK1466 worms and they have prolonged their mean lifespan with potential antioxidant ability by overcoming stress responses. Overall, our study reported herein demonstrated that the complexes 1 and 4 could be established as potential metallo-drugs substantiating further exploration.

Coordination of N, O-donor Appended Schiff Base Ligand N, N’-bis (3-Methoxy Salicylidenimino-1,3-diaminopropane) towards Nickel (II), Copper (II) and Zinc (II) : Synthèses, Crystal Structure

New complexes prepared by the reaction of N,N’-bis(3-methoxysalicylidenimino-1,3-diaminopropane) (H2L) with Ni(II), Zn(II) and Cu(II) ions are reported in this paper. The H2L ligand is structurally characterized by elemental analysis, NMR, infrared, UV-Vis spectroscopies, conductance and magnetic room temperature measurement. The mononuclear complex of Ni(II) (C19H24N2NiO6) is characterized by single X-ray diffraction. The compound crystallizes in the orthorhombic system in the space group Pnma with the unit cell parameters a = 7.3754(5) Å, b = 21.9576(13) Å, c = 11.5546(6) Å, α = 90°, β = 90°, γ = 90° The ligand H2L acts in tetradentate fashion in its di-deprotonated form. Two coordinated water molecules complete the coordination sphere. The environment around the Ni(II) center is best described as an octahedral geometry.

Investigating spectroscopic properties, biological effects, and molecular docking studies of synthesized Schiff base metal complexes

In this current investigation, we have accomplished the synthesis of a Schiff base ligand termed (E)-4-methyl-N′-(2,4,5-trimethoxybenzylidene)benzohydrazide (HL) through a reversible condensation reaction, which engaged a carbonyl compound and a primary amine. This synthesized Schiff base ligand, HL, served as the foundation for the preparation of two metal complexes, namely, M1L (Cu complex) and M2L (La complex). To characterize these compounds, we employed various analytical techniques, including thermogravimetric studies, elemental analysis, powder X-ray diffraction, FT-IR spectroscopy and 1H NMR. The examination of powder X-ray diffraction data provided valuable insights into the crystalline structures of the Cu and La complexes. These shifts are indicative of structural changes in the complexes. Our electronic spectrum analysis revealed the pivotal involvement of the ligand in promoting charge transfer processes, substantiated by an increased concentration of charge transfer transitions observed when the ligand was present. Additionally, we evaluated the antibacterial efficacy of the Schiff base ligand HL and its metal complexes (Cu, La) against a spectrum of bacteria, encompassing both gram-positive (Bacillus subtilis, Enterococcus faecalis) and gram-negative (Escherichia coli) strains. In the current investigation, we utilized molecular docking techniques to explore the interactions between the synthesized HL and its M1L and M2L complexes with protein receptor molecules. These results highlighted the favorable binding energies and stable interactions of these compounds with the protein receptor, M1L displayed notably more stable interactions and lower binding energy compared to M2L. This suggests that M1L may have a stronger potential impact on the free binding energy and molecular interactions.

Novel half-sandwich ruthenium(II) nicotinic hydrazone complexes: An efficient class of catalyst for the N-alkylation of amines with benzyl alcohol via transfer hydrogen mechanism and effective antibacterial agents

A new series of half sandwich ruthenium(II) complexes supported by nicotinic acid hydrazone derivatives of general formula [Ru(ɳ6-p-cymene)(Cl)(L)], where L represents N’-benzylidenenicotinohydrazide (HL1), N’-(naphthalen-1-ylmethylene)nicotinohydrazide (HL2) or N’-(pyren-1-ylmethylene)nicotinohydrazide (HL3) were synthesized and fully characterized. The solid-state molecular structures of ligands and complexes were elucidated with single-crystal X-ray diffraction. The ligands HL1 and HL2 possess monoclinic crystal system with P21/c and C2/c space groups respectively, whereas all the three Ru(II) complexes C1–3 are typical three-legged piano-stool geometries with orthorhombic(Aba2) (C1) and triclinic(P-1) (C2–3) systems respectively. The catalytic activities of these ruthenium complexes in the synthesis of N-alkylated amines were explored. Under optimal reaction condition, the complex C3 was found to be the most efficient catalyst for the N-alkylation of primary to secondary amines using benzyl alcohol. A wide range of substrates have been studied that includes anilines bearing electron withdrawing/electron donating group, fused aromatic, heteroaromatic, alicyclic and aliphatic amines with good to excellent yield. In addition, the antibacterial activity of the complexes were tested against different human pathogenic bacteria, among them C2 complex with naphthyl moiety was found to be the most active one against both Gram-positive (S. aureus and E. faecalis) and Gram-negative (E. coli and K. pneumoniae) bacteria. These two different studies demonstrate the catalytic and biological importance of our newly prepared Ruthenium complex.

Structural, spectral and thermal characteristics of new tetrakis-complexes (NEt4)[LnL4] with dimethyl(4-chloro-3-nitrobenzoyl)amidophosphate

In continuation of the studies of new promising phosphors a new representative of carbacylamidophosphates (CAPhs) was synthesized and used as a ligand to obtain new lanthanides complexes (NEt4)[LnL4] (Ln = La, Y, Ce – Nd, Sm – Lu; L- = {C6H3(4-Cl-3-NO2) CONPO(OCH3)2}-). The structure of “free” ligand HL and complexes (NEt4)[YbL4] and (NEt4)[LuL4] were established by X-ray diffraction analysis. Dimethyl(4-chloro-3-nitrobenzoyl)amidophosphate has a dimeric structure. Dimers are formed by means of two hydrogen bonds of NH···OP type between two neighboring molecules. In the structure of the complexes the ligands are coordinated to the metal ion by the PO and CO groups of the chelate fragment forming six-membered not planar rings. In the crystal, the ligand and the complexes form numerous intermolecular contacts, including specific Cl···O intramolecular interaction. For the obtained compounds absorption, 1H NMR, and IR spectra were recorded and analyzed. Thermal gravimetric analysis and luminescence spectroscopy at 77 K and 298 K were used to characterize the obtained complexes.

Structural and theoretical exploration of an innovative unsymmetrical oxovanadium complex: Electrochemical analysis and in vitro antibacterial screening

2‑hydroxy-1-naphthaldehyde and 3,4-diaminotoluene were reacted with bis(acetylacetonato) oxovanadium to yield a novel NNOO -type chelate complex, VOL. The prepared complex is characterized by employing elemental analysis, electronic and infrared spectra. The expected structure was crystallized and identified by using the single-crystal X-ray diffraction method. The VOL complex crystallizes in the monoclinic system with the P21/c space group. Additionally, we affected a comprehensive analysis of VOV, VOIV and VOIII complexes focusing on their structural, electronic, and optical properties using DFT and TD-DFT calculations in gas. The computed parameters closely matched the experimental data, demonstrating good agreement. The electrochemical behavior of the VOL complex, investigated on a glassy carbon electrode (GCE) by means of cyclic voltammetry (CV), revealing a metal-centered one-electron redox systems corresponding to the VOIV/VOIII and VOV/VOIV at -1206 and 547 mV/SCE respectively. The in vitro antibacterial activities of the free ligand H2L and the corresponding VOL complex were evaluated against Gram-positive strains, Staphylococcus aureus and Streptococcus pyogenes, and Gram-negative strains, Escherichia coli, Proteus mirabilis and Klebseilla pneumoniae. The biological screening revealed that the VOL complex exhibits more potent activity than the free ligand.

Temperature Dependence of the Ring Opening of Cyclopropene Imines on Thorium Metallocenes.

The reactions of two highly strained cyclopropenimine ligands L1H and L2H (L1H = N1,N1,N2,N2-tetraisopropyl-3-iminocycloprop-1-ene-1,2-diamine, L2H = N1,N1,N2,N2-tetracyclohexyl-3-iminocycloprop-1-ene-1,2-diamine) with three thorium precursors Cp*2ThCl2, Cp*2Th(Cl)(CH3), and Cp*2Th(CH3)2 were studied. At -20 °C, L1H and L2H react with Cp*2ThCl2 to form Th1 (Th1 = Cp*2ThCl2(L1H)) and Th2 (Th2 = Cp*2ThCl2(L2H)), respectively, where the neutral ligand coordinates to the thorium metal center. Coordination of the ligand to the thorium metal center introduces aromaticity at the cyclopropene ring of the ligand. Reaction at room temperature results in the ring opening of the ligand to form Th3 (Th3 = Cp*2ThCl2((Z)-2,3-bis(diisopropylamino)acrylonitrile) and Th4 (Th4 = Cp*2ThCl2((Z)-2,3-bis(dicyclohexylamino)acrylonitrile), where the cyclopropenimine converts into a nitrile and coordinates to the thorium metal center. Reaction of L1H and L2H with Cp*2Th(Cl)(CH3) and/or Cp*2Th(CH3)2 at -20 °C results in a rapid methanolysis reaction and forms Cp*2Th(L1/L2)(CH3/Cl)-type complexes Th5 (Th5 = Cp*2Th(L1)(CH3)), Th6 (Th6 = Cp*2Th(L2)(CH3), Th7 (Th7 = Cp*2Th(L1)(Cl), and Th8 (Th8 = Cp*2Th(L2)(Cl). On the other hand, at room temperature, these reactions result in a ring opening of the ligand. Room-temperature reaction of L1H and L2H with Cp*2Th(CH3)2 results in Th9 (Th9 = Cp*2Th(CH3)((Z)-3-imino-N1,N1,N2,N2-tetraisopropylbut-1-ene-1,2-diamine) and Th10 (Th10 = Cp*2Th(CH3)((Z)-3-imino-N1,N1,N2,N2-tetracyclohexylbut-1-ene-1,2-diamine). Similarly, at room temperature, L1H and L2H react with Cp*2Th(Cl)(CH3) to form Th11 (Th11 = Cp*2Th(Cl)((Z)-3-imino- N1,N1,N2,N2-tetraisopropylbut-1-ene-1,2-diamine) and Th12 (Th12 = Cp*2Th(Cl)((Z)-3-imino-N1,N1,N2,N2-tetracyclohexylbut-1-ene-1,2-diamine). The ring-opening reaction is assisted by the nucleophilic attack of the thorium-coordinated methyl group to the highly strained cyclopropene imine carbon.

3-Phenoxybenzaldehyde and Glycine-Derived Schiff base M(II) Complexes: Synthesis, molecular Modeling, spectroscopic Exploration, and antimicrobial evaluation

This study synthesized a novel bidentate Schiff base known as 2-((3-phenoxybenzylidene)amino)acetic acid (HL) derived from glycine and 3-phenoxy benzaldehyde and its M(II) complexes (M = Co2+, Cu2+, Ni2+ & Zn2+) was prepared by combining the Schiff base (HL) and the metal acetates in a 1:2 ratio. The molecular structure of the Schiff base was confirmed using CHN analysis, mass, FT-IR, UV–Vis, 1H NMR and 13C NMR spectra. The prepared complexes were analyzed using CHN analysis, mass, FT-IR, UV–Vis, molar conductivity studies, magnetic susceptibility studies, and ESR for Cu(II) complexes. Based on the analysis, square planar geometry is suggested for the Cu(II) & Ni(II) complexes and tetrahedral geometry for Co(II) and Zn(II) complexes. A preliminary in vitro antimicrobial investigation of the synthesized ligand and its related complexes has been performed. The M(II) complexes showed more potent antimicrobial activity than its Schiff base; in particular, the Cu(II) complex illustrated notable inhibitory effects. Molecular docking studies were conducted against CDK2 (PDB ID: 1B39), α-amylase (PDB ID: 4W93), and α-glucosidase (PDB ID: 3TOP). The Ligand HL demonstrated AutoDock/MM-GBSA binding energy values of −5.9 /-104 kcal mol−1 (CDK2), −6.6 /-134 kcal mol−1 (α-amylase), and −7.4/ −174.84 kcal mol−1 (α-glucosidase). The complexes exhibited MM-GBSA binding energy values within the range of −198.20 to −198.72 kcal mol−1 (CDK2), −250.00 to −250.02 kcal mol−1 (α-amylase), and −279.51 to −283.84 kcal mol−1 (α-glucosidase). The molecular docking results shed light on the potential of ligand HL and its metal complexes as promising candidates for further exploration in therapeutics, particularly in targeting CDK2 inhibition (anticancer) and α-amylase and α-glucosidase inhibition (antidiabetic).

DNA interaction, biological, and structural identification studies of bivalent nano‐sized Nickel, Palladium, and Platinum chelates of 2‐(((Z)‐6‐chloro‐3‐((E)‐([2‐hydroxyphenyl]imino)methyl)‐4H‐chromen‐4‐ylidene)amino)phenol Schiff base ligand

New nano‐sized Ni(II), Pd(II), and Pt(II) Schiff base chelates of 2‐(((Z)‐6‐chloro‐3‐((E)‐([2‐hydroxyphenyl]imino)methyl)‐4H‐chromen‐4‐ylidene)amino)phenol were designed and manufactured. The structural characterization of these isolated compounds was accomplished through spectral measurements, thermal and elemental analyses, and magnetic moment and conductivity determinations. The nano‐sized metal(II) complexes molar conductance indicated that they exhibited non‐electrolytic behavior. The UV–Vis spectral data and magnetic moment provided evidence for producing octahedral geometries in the nano‐sized complexes of Ni(II), Pd(II), and Pt(II). Metal chelates' thermal characteristics and decomposition kinetics were examined through Coats‐Redfern technique. The kinetic aspects, including pre‐exponential factor (A), the entropy of activation (ΔS), and activation energy (E) were enumerated. The X‐ray diffraction (XRD) calculations results of the trivalent metal complexes showed that sharp and intense diffraction peaks signify their crystalline properties with nanoscale particle size, and another proof was obtained from the images of SEM, TEM, EDX, and AFM also homogeneous distribution over the complex surface was confirmed. Molecular modeling techniques were adopted to optimize the metal complexes geometry. The viscosity and UV–Vis absorption determinations were utilized to assess the calf thymus DNA (CT‐DNA) interaction with the nano‐sized metal(II) chelates. The acquired data revealed that the complexes exhibit a non‐intercalative or incomplete binding pattern when interacting with DNA. The calculated DNA‐complexes binding constants are 3.93 ± 0.02 × 10,4 1.67 ± 0.3 × 105 and 2.88 ± 0.03 × 105 M−1, for nano‐sized Ni(II), Pd(II) and Pt(II) Schiff base chelates, successively. Both Gram‐negative (Escherichia coli and Pseudomonas aeruginosa) and Gram‐positive (Bacillus subtilis and Streptococcus pneumoniae) micro‐organisms were tested against H2L Schiff base ligand and its nano‐sized metal(II) complexes. Candida albicans and Aspergillus fumigatus were tested for antifungal activity, revealing that most complexes had activity lower than H2L ligand, while the complex of Ni(II) exhibited no discernible antifungal activities. Furthermore, the manufactured complexes underwent testing for their in‐vitro anticancer and antibacterial effectiveness. Furthermore, the complexes antioxidant activity was appraised through DPPH and ABTS inhibition tests, revealing distinct scavenging abilities on DPPH radicals. The complexes were ordered according to their scavenging capacity as follows: Ni(II) complex &gt; Pd(II) complex &gt; Pt(II) complex. Finally, the study of cell cycle arrest by the Ni(II), Pd(II), and Pt(II) complexes on HEPG2 has also been performed through flow cell cytometry.

Co(II) Metal-Organic Complex: Fluorescence Performances and Loaded With Drug Vitamin B2 Hydrogels Against Recurrent Oral Ulcers.

A new coordination polymer (CP) based on Co(II), namely, {[Co3(L)2(4,4'-bipy)(DMA)2]·H2O}n(1) has been synthesized after reacting Co(NO3)2·6H2O with H3L ligand in the existence of N-donor ligand 4,4'-bipyridine (4,4'-bipy), via utilizing a flexible tricarboxylic acid ligand 5-((formic acid-3-sulfur)methyl)isophthalic acid (H3L) with -S-CH2- joint. Additionally, the excellent blue fluorescence properties of CP 1 were confirmed through fluorescence spectroscopy compared to the original ligand. Using natural polysaccharide hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) as raw materials, HA/CMCS hydrogel was prepared by chemical synthesis method. Taking vitamin B2 as the drug model, we designed and synthesized gels loaded with vitamin B2 metal framework and evaluated their efficacy in the treatment of recurrent oral ulcer.