Aroylhydrazone Complexes Research Articles

Analysis of antiproliferative activity of new half-sandwich arene Ru(II) thiophene based aroylhydrazone complexes.

Efforts in researching the efficient anti-tumor properties of three novel arene ruthenium(II) complexes incorporating thiophene-based aroylhydrazone ligands have been undertaken. The complexes' elemental composition was [(η6-p-cymene)Ru(L)Cl]. They were comprehensively characterized through elemental and spectroscopic analyses (FT-IR, UV-vis, NMR, and HR-MS). Single crystal X-ray diffraction studies revealed a pseudo-octahedral geometry with bidentate coordination of the ligands in a representative complex. The in vitro assessment of the complexes' cancer cell growth inhibition was conducted using the MTT assay against A549 (human lung carcinoma), HeLa (human cervical carcinoma), HuH-7 (hepatocellular carcinoma), and NIH-3T3 (mouse fibroblast non-cancerous cell line). Results indicated significant cytotoxicity across all cancer cell lines, with IC50 concentrations of complex 2 being 6.8 μM for A549, 11.6 μM for HeLa, and 9.4 μM for HuH-7, compared to cisplatin with IC50 values of 18.9 μM, 17.68 μM, and 24 μM respectively. Notably, complex 2 demonstrated particularly promising cytotoxicity against all tested cancerous cell lines. Fluorescent staining analysis such as acridine orange/ethidium bromide (AO-EB) and HOECHST 33342 revealed cell death mechanisms involving membrane disintegration and nuclear condensation following treatment with complex 2. Further studies were conducted to measure reactive oxygen species (ROS) levels using the dichlorodihydrofluorescein diacetate (DCFH-DA) assay, and mitochondrial membrane potential (MMP) was assessed using the JC-1 dye assay. These studies demonstrated that complex 2 increased ROS levels, decreased membrane potential, and promoted mitochondrial dysfunction-mediated cell death pathways. Additionally, flow cytometry analysis, utilizing dual staining of Annexin V-FITC and propidium iodide (PI), was employed to quantitatively study apoptosis induction.

Pyrene aroylhydrazone-based Pd(II) complexes for DNA/protein binding, cellular imaging and in vitro anticancer activity via ROS production

A novel class of Pd(II) pyrene aroylhydrazone complexes (Pd1–Pd4) of general formula [Pd(L)(PPh3)Cl] (L = pyrene aroylhydrazones) was synthesized and their solid-state structures were determined by single-crystal XRD study. In vitro cytotoxicity of Pd1–Pd4 were examined against two cancer cell lines, HeLa and MCF-7 and two non-cancerous cell line, HEK 293T and 3T3-L1 to assess their selectivity. Among these, Pd2 and Pd3 had the most significant cytotoxic effects in comparison to cisplatin, a traditional anticancer medication featuring undesirable side effects, in tested cancer cell lines. Moreover, they showed noticeably less toxicity towards non-cancerous cell lines. Their interactions with serum albumin were confirmed experimentally as well as with molecular docking. Pd3 was also found to effectively interact with DNA as revealed by DNA interactions studies. Pd3-treated HeLa cells exhibited nuclear apoptotic features such as chromatin condensation and nuclear fragmentation and was also found to induce ROS which further led to decrease in mitochondrial membrane potential in cancer cells. Further, Pd3 was efficiently internalized by HeLa cells as evident from cellular imaging using confocal microscopy. Taken together, we report a novel class of Pd(II) pyrene aroylhydrazone complexes displaying strong protein/DNA binding and anti-cancer activity via ROS generation under in vitro circumstances.

Syntheses, structural characterizations, and catalytic activities of manganese(II)-aroylhydrazone complexes

An aroylhydrazone, di-2-pyridyl ketone-4-methoxybenzhydrazone monohydrate (DKMBH·H2O), and its three Mn(II) complexes, [Mn(DKMB)2]·H2O (1), [Mn(DKMB)Cl] (2), and [Mn(DKMB)NO3] (3), were synthesized. The physicochemical properties of the aroylhydrazone and metal complexes were revealed using various methods, e.g., Fourier transform infrared (IR) spectroscopy, ultraviolet-visible spectroscopy, mass spectrometry, and 1H nuclear magnetic resonance (NMR) spectroscopy, in addition to analyses such as CHN elemental and thermal analyses and molar conductivity studies. The molecular structures of the aroylhydrazone and manganese complex, 1 were elucidated using single-crystal X-ray diffraction (XRD) analyses.IR spectroscopy, 1H NMR spectroscopy, and single-crystal XRD showed that the aroylhydrazone occurred in the amido form in the solid state. According to the results of XRD, the aroylhydrazone coordinated to the Mn(II) center via the pyridine and azomethine N atoms and iminolate O atom, with a distorted octahedral geometry, in bis-ligated complex, 1.The results of IR spectroscopy further supported the tridentate character of the aroylhydrazone. Furthermore, the Mn complexes displayed potential as catalysts in cyclooctene epoxidation. Among the three Mn complexes, the use of [Mn(DKMB)2]·H2O (1) resulted in a 92% conversion, with an epoxide selectivity of 95%.

Synthesis, crystal structures, and catalytic oxidation of olefins of dioxomolybdenum(VI) complexes with aroylhydrazone ligands

Two Mo(VI) aroylhydrazone complexes, cis-[MoO2(L1)(CH3OH)] (I) and cis-[MoO2(L2)(CH3OH)] (II), derived from 2-bromo-N'-(3,5-dibromo-2-hydroxybenzylidene)benzohydrazide (H2L1) and 2-bromo-N'-(2-hydroxy-4-methoxybenzylidene)benzohydrazide (H2L2), respectively, are reported. The complexes were characterized by elemental analyses, infrared and electronic spectroscopy, and single crystal structure analysis (CIF files CCDC nos. 1443679 (I) and 1443678 (II)). The Mo atoms are coordinated by two cis terminal oxygen, ONO from the aroylhydrazone ligand, and methanol oxygen. Complex I crystallized as monoclinic space group P21/c with unit cell dimensions a = 8.075(2), b = 13.905(1), c = 16.448(1) A, β = 91.282(2)°, V = 1846.5(4) A3, Z = 4, R1 = 0.0859, wR2 = 0.2066. Complex II crystallized as triclinic space group P\(\overline 1 \), with unit cell dimensions a = 8.0824(6), b = 10.5919(8), c = 10.7697(8), α = 96.432(2)°, β = 97.438(2)°, γ = 103.119(2)°, V = 880.8(1) A3, Z = 2, R1 = 0.0271, wR2 = 0.0571. The complexes were tested as catalyst for the oxidation of olefins and showed effective activity.

From cadmium(II)-aroylhydrazone complexes to metallopolymers with enhanced photoluminescence. A structural and DFT study

Reaction of cadmium(II) acetate and donor-acceptor conjugated O,N,O ligands led to complexes with coordinated pyridine and to polymeric materials by grafting onto poly(4-vinylpyridine). All the synthesized compounds exhibited luminescent properties. Two ligands series with and without a bulky end group produced molecular structures with a dinuclear arrangement. Structural and photophysical properties were systematically explored and compared to previously reported zinc complexes. Benzothiazole containing ligands revealed a new coordination mode with respect to zinc. Quantitative emission measurements were performed on solid samples of complexes and polymers. Differences of photoluminescence quantum yields in molecular complexes and grafted polymers were revealed. Experimental absorption and emission data were explained by theoretical calculations on crystalline and insulated models.

Synthesis, structure and anticancer activity of (η6-benzene) ruthenium(II) complexes containing aroylhydrazone ligands

New benzene ruthenium(II) aroylhydrazone complexes of general molecular formula [Ru(η6–C6H6)Cl(L)] (where L = aroylhydrazone ligand) have been synthesized from the reaction of the precursor [Ru(η6–C6H6)(μ-Cl)Cl]2 and aroylhydrazone ligands. The composition of the complexes has been accomplished by elemental analysis and spectral methods (FT-IR, UV-Vis, 1H NMR). The molecular structure of complex 4 has been established by single-crystal X-ray structure analysis shows that the aroylhydrazone ligands are coordinated to ruthenium as a bidentate N, O donor and a typical piano stool geometry was observed around ruthenium(II) metal center. All the complexes exhibit two consecutive irreversible oxidations in the potential range +0.74 to +1.17 V (RuII/RuIII;RuIII/RuIV) Vs calomel electrode. Further, in vitro anticancer activity of complexes 1–4 on human breast cancer cell line (MCF-7), human cervical cancer cell line (HeLa) and non-cancerous NIH-3T3 cell line exhibit moderate to excellent cytotoxic activity. It is also evident from IC50 values that the complexes are more potent against MCF-7 cells than cisplatin. The superior activity of the complex 4 assumes that presence of electron donating methoxy substituent which makes the ring more reactive. Further, the morphological changes during cell death were investigated by Acridine Orange-Ethidium Bromide (AO–EB) and DAPI staining techniques, which confirm the complex 4 induces cell death only through apoptosis.

Synthesis and characterisation of cycloruthenated benzhydrazone complexes: catalytic application to selective oxidative cleavage of olefins to aldehydes

The synthesis and structural characterisation of cyclometalated ruthenium(ii) aroylhydrazone complexes have been described. The complexes were developed as effective catalysts for oxidative cleavage of olefin reactions.

Synthesis, characterization, DNA/protein binding and in vitro cytotoxic evaluation of new Ru(III) complexes containing aroylhydrazone ligands: Does hydrogen bonding influence the coordination behavior of hydrazones?

A new set of ruthenium(III) aroylhydrazone complexes [RuCl2(PPh3)2(HL1)] (1) and [RuCl(PPh3)2(L2)] (2) were synthesized by reacting salicylaldehyde p-toluic acid hydrazone (H2L1) or 2-hydroxy-acetophenone p-toluic acid hydrazone (H2L2) and [RuCl3(PPh3)3] precursor complex and characterized. Single crystal X-ray diffraction data of these complexes revealed a distorted octahedral geometry around ruthenium ions fulfilled by NOP2Cl2 atoms and NO2P2Cl atoms, respectively. Though the ligands look similar in respect of structure and donor sites, the existence of H-bonding between the phenolic –OH and N2 nitrogen of the coordinated ligand H2L1 as revealed by the single crystal data of complex 1 is attributed to the non-involvement of the hydroxyl group in coordination to the ruthenium ion which is in sharp contrast to the behaviour exhibited by the ligand H2L2 in complex 2. As a result, the ligand H2L1 acted as a monobasic bidentate against the dibasic tridentate behaviour of the ligand H2L2. Binding interactions of these complexes with calf thymus-DNA (CT-DNA) estimated by absorption and emission spectroscopy did demonstrate the intercalative mode of binding. The capability of complexes 1 and 2 to bind with bovine serum albumin (BSA) protein was monitored by quenching of tryptophan and tyrosine residues using UV–Vis, fluorescence and synchronous fluorescence methods. Further, in vitro cytotoxicity of the complexes was carried out using MTT, lactate dehydrogenase (LDH), Nitric oxide (NO), reactive oxygen species (ROS) and propidium iodide (PI) staining assays against non-small cell lung cancer cell line (A549).

Dinuclear vanadium, copper, manganese and titanium complexes containing O,O,N-dichelating ligands: Synthesis, crystal structure and catalytic activity

O,O,N- or O,N-dichelating ligands, H4L1, H4L2, derived from new bis(hydroxybenzylidene)-substituted terephthalo and oxalo hydrazides were prepared and characterized by FT-IR and NMR spectroscopy (H4L1=dicondensation of salicylaldehyde and terephthalic acid dihydrazide, H4L2=dicondensation of salicylaldehyde and oxalic acid dihydrazide). [{VO2}2(H2L1)] (1), [{Cu(CH3OH)}2(L1)] (2), [{Mn(CH3OH)}2(L1)] (3) and [TiO(H3L1)2] (4) complexes of the potentially hexadentate 2[ONO] donor hydrazone ligand [L1]4− were synthesized by reaction of the appropriate metal salts with H4L1. The complexes [{VO(CH3O)(CH3OH)}2(L2)] (5), [{Cu(CH3OH)}2(L2)] (6), [{Mn(H2O)2(CH3OH)}2(L2)] (7) and [{TiO(CH3OH)}2(L2)]·2H2O (8) were synthesized by the reaction of corresponding metal salts with H4L2. All complexes were characterized by microanalyses, FT-IR, UV–Vis and NMR spectroscopic methods. The crystal structures of 1 and 5 were established by X-ray analyses. Compound 1 is a one-dimensional coordination polymer. The catalytic potential of the complexes was evaluated for oxidation of hydrocarbons including cycloalkenes, cyclic alkanes and benzylalcohol using H2O2 as terminal oxidant. Of the studied aroylhydrazone complexes, 4 showed the best selectivity and activity as catalyst.

Syntheses, Structures, and Catalytic Activity of Copper(II)‐Aroylhydrazone Complexes

AbstractTwo CuII complexes of tridentate Schiff base ligands, [Cu(L1)(CH3OH)2]NO3·CH3OH (1) and [Cu2(L2)2(CH3OH)2](NO3)2 (2), were prepared and characterized by elemental analyses and spectroscopic methods [H2L1 = (E)‐N‐(4‐hydroxy benzoic acid (2‐hydroxy‐3‐methoxybenzylidene)benzohydrazide, and H2L2 = (E)‐N‐4‐hydroxy benzoic acid (5‐bromo‐2‐hydroxybenzylidene)benzohydrazide]. The crystal structures of 1 and 2 were established by X‐ray crystallography. The complex cation in 1 is based on a square pyramid with the uninegative Schiff base coordinating in a tridentate mode via O, N, O′‐donor atoms with the remaining sites being occupied by two methanol oxygen atoms with one of these in the axial position. By contrast, the Schiff base coordinates in a tridentate ligand fashion in dinuclear compound 2 as the phenoxide oxygen atom bridges two central copper atoms. The NO4 coordination donor set is completed by a methanol oxygen atom, which occupies an axial position in the distorted square pyramidal arrangement. Complexes 1 and 2 are very active catalysts in clean epoxidation reactions using aqueous hydrogen peroxide and acetonitrile. The effects of reaction parameters such as solvent and oxidant in the epoxidation of cis‐cyclooctene were investigated and showed that cyclooctene and cyclohexene were oxidized efficiently to their corresponding epoxide with 100 and 31 % selectivity, respectively, in the presence of catalyst 2. This catalytic system showed also excellent selectivity in the oxidation of benzyl alcohol.

Mixed-ligand aroylhydrazone complexes of molybdenum: Synthesis, structure and biological activity

The reaction of the benzoylhydrazone of 2-hydroxybenzaldehyde (H2L) with [MoO2(acac)2] proceeds smoothly in refluxing ethanol to afford an orange complex [MoO2L(C2H5OH)] (1). The substrate binding capacity of 1 has been demonstrated by the formation and isolation of two mononuclear [MoO2L(Q)] {where Q=imidazole (2a) and 1-methylimidazole (2b)} and one dinuclear [(MoO2L)2(Q)] {Q=4,4′-bipyridine (3)} mixed-ligand oxomolybdenum complex. All the complexes have been characterized by elemental analysis, magnetic and spectroscopic (IR, UV–Vis and NMR) measurements. The molecular structures of all the oxomolybdenum(VI) complexes (1, 2a, 2b and 3) have been determined by X-ray crystallography. In each complex, the dianionic planar ligand is coordinated to the metal centre via one enolate oxygen, one phenolate oxygen and an azomethine nitrogen atom. The complexes have been screened for their antibacterial activity against Escherichia coli, Bacillus and Pseudomonas aeruginosa. The minimum inhibitory concentration of these complexes and their antibacterial activity indicates that compounds 2a and 2b are potential lead molecules for drug designing.

Iron(III) aroylhydrazone complexes: Structure, electrochemical studies and catalytic activity in oxidation of olefins

Tridentate Schiff base ligands derived from aromatic aldehydes and benzhydrazide, and their iron complexes [Fe(L 1)(HL 1)] 1, [Fe(HL 1)Cl 2(CH 3OH)]·(CH 3OH) 2 and [Fe(HL 2)Cl 2(H 2O)] 3 have been prepared and characterized (H 2L 1 = ( E)- N′-(2-hydroxy-3-methoxybenzylidene)benzohydrazide, H 2L 2 = ( E)- N′-(5-bromo-2-hydroxybenzylidene)benzohydrazide). The crystal structure of 2 has been determined. The electrochemical properties of these complexes have been investigated by cyclic voltammetric technique in acetonitrile solutions. Electrochemical studies have revealed quasi-reversibility for these compounds. The catalytic potential of these complexes has been tested for the oxidation of cyclooctene using tert-butylhydroperoxide (TBHP) as oxidant. The effects of the molar ratio of oxidant to substrate, the temperature, the co-catalyst concentration and the solvent have been studied. Excellent selectivities have been obtained for the epoxidation of cyclohexene, cyclooctene, norbornene, cis- and trans-stilbene.

Synthesis, Crystal Structures of Y(III) and Ni(II) Aroylhydrazones Complexes and π–π Interactions in the Crystal

Two novel aroylhydrazone complexes [Y(HL1)4(H2O)4](NO3)3(MeOH)6 1, [Ni(HL2)SO4](H2O)6 2, (HL1=4,5-diazafluorene-9-one isonicotinoylhydrazoneand HL2=2-pyridylaldehyde furoylhydrazone) were synthesized and structurally characterized by means of X-ray single-crystal diffraction. There are strong intermolecular π–π stacking interactions in the complexes 1 and 2, especially complex 1 was stabilized by the intermolecular and intramolecular π–π stacking interactions.

An electrochemical study of oxygen adducts of cobalt-benzaldehyde aroylhydrazone complexes in dimethylformamide

1. Oxygen adducts of cobalt chelates with benzaldehyde benzoyl- and salicyloylhydrazines have been synthesized for the first time and have been studied electrochemically in DMFA. 2. The kinetic nature of the chelate reduction current in the second wave is explained by the cleavage of the oxygen adduct during electrolysis, after transfer of the first electron. 3. The cyclic voltamperometric method has established the formation of intermediate complex particles with metal in the zero oxidation state.

ESR Study of the Brown - form of Some Copper (II) Aroylhydrazone Complexes

Abstract ESR study of the brown - modification of some copper (II) - aroylhydrazone complexes revealed a reduction in the type of polycrystalline spectra which have been noticed for the corresponding green - form complexes. The estimated values of both magnetic susceptibility and magnetic moment were less than those for the green chelates.

E.S.R Study of Some Copper (II) - Aroylhydrazone Complexes

Abstract E.S.R method was applied to investigate some copper (II) aroylhydrazone complexes. From the experimental spin - Hamiltonian parameters; symmetry, bonding character and electron delocalization were determined. Complexes exhibited a changing fraction of the metal 4s character in their |x2 - y2> ground state.

Coordination compounds of hydrazine derivatives with transition metals. X. Cobalt(II) aroylhydrazone complexes

Abstract The reactions of some aroylhydrazones (HL) with cobalt(II) salts were investigated and chelates of the types [Co(HL) 2 X 2 ] and [Co(L) 2 ] were isolated. Analytical data, infrared studies, magnetic moments and solution spectra as well as some conductivity measurements were used to characterise these chelates. The [Co(HL) 2 X 2 ] chelates were found to possess octahedral configuration in solid state but dissociate in DMF solutions. Attempts were made to identify the dissociation products. A dimeric pentacoordinate structure was tentatively assigned for the neutral [Co ( L ) 2 ] chelates.