Thiazole Ligand Research Articles

Water oxidation through electrocatalytic process using cobalt and nickel complexes of thiazole Schiff-base ligands

Ni(OAc)2.4H2O and CoCl2.6H2O reacted with thiazole ligands, HL and HL' (where HL= (E)-2-(((4-phenylthiazol-2-yl)imino)methyl)phenol and HL'= (Z)-2-(2-benzylidenehydrazinyl)-4-phenylthiazole, in ethanol to create new mononuclear Co(II) and Ni(II) complexes, CoL2, NiL2, CoL'2, and NiL'2 (1-4). X-ray diffraction analysis, spectroscopic, and electrochemical methods were used to study the complexes. A carbon paste electrode that had been modified by complexes 1-4 was used as the working electrode in a three-electrode setup to test the complexes' ability in water oxidation reaction at pH 13. The linear sweep voltammetry (LSV) curves showed that complexes 3 and 2 have much greater activity and only require the overpotential of 570 and 690 mV ʋs. RHE at a current density of 10 mA/cm2 with Tafel slopes of 86.92 and 94.19 mVdec−1 respectively in an alkaline solution. In addition, the amperometry tests exhibited brilliant stability for water oxidation by CPE-complex 3 and CPE-complex 2 under electrochemical conditions at pH 13. Although X-ray diffraction patterns did not display a crystalline structure, the scanning electron microscopy images displayed that cobalt oxide and nickel oxide in an alkaline condition are proper catalysts for water oxidation reaction on the surface of the modified electrode.

A luminescent Zn(II) metal−organic framework assembled with a thiazolothiazole chromophore for sensing mainly cobalt(II) and nitrofuran antibiotics in aqueous solutions

The accumulation of cobalt(II) and antibiotics in the environmental water system has posed a significant threat to both human health and the safety of the ecological environment. Therefore, it is of utmost importance to look for a proficient means to detect cobalt(II) and antibiotics. Herein, we introduce a luminescent Zn-MOF, constructed with a thiazolo[5,4-d]thiazole ligand that features a chromophore group, which serves as a sensor to detect cobalt(II) and antibiotics. The Crystal structure of {[Zn2(OBA)2(4bpyttz)]·2DMF} (1) (4bpyttz=2,5-bis(pyridine-4-yl)thiazolo[5,4-d]thiazole, H2OBA=4,4′-oxybis(benzoic acid)) displayed a 6-c net three-dimensional (3D) framework structure with novel topological type denoted as {44·610·8}. Moreover, luminescence sensing studies demonstrated that 1 exhibits high selectivity and multi-responsiveness of multiple ions mainly for Co2+, and nitrofuran antibiotics mainly for NZF, and NFT in an aqueous medium inducing turning-off effects. The detection limits are determined to be 1.14, 0.14, and 0.072 μM for 1, respectively. Additionally, MOF-derived fluorescence test papers and composite films were utilized for the visual detection of Co2+, NZF, and NFT, thereby expanding the potential applications of the system in real-world sensing. Furthermore, the potential luminescence quenching mechanism of MOF 1 regarding Co2+ ions and nitrofuran antibiotics could be deduced through various characterization methods.

Amino-induced cadmium metal–organic framework based on thiazole ligand as a heterogeneous catalyst for the epoxidation of alkenes

Selective epoxidation of olefins is of high interest in the chemical industry due to the many applications of epoxides. This study reports on the synthesis of Cd-MOF, [Cd(DPTTZ)(5-AIP)] (IUST-1) (where DPTTZ = 2, 5-di (pyridine-4-yl) thiazolo [5, 4-d] thiazole, 5-AIP = 5-Aminoisophthalic acid), by a reflux method, which can be considered as a fast and simple process. The morphology and structure of the synthesized IUST-1 were determined by using FE-SEM (Field Emission Scanning Electron Microscopy), EDX (Energy Dispersive Analysis of X-ray), Mapping (Elemental Mapping), CHNS (Elemental analysis), XRD (X-Ray Diffraction), FT-IR (Fourier Transform Infrared), and TGA (Thermo Gravimetric Analysis). The epoxidation of cyclooctene was investigated using the activity of catalytic IUST-1. The results showed that in the presence of tert-butyl hydroperoxide and CCl4 in a 1:2 alkene/oxidant ratio, a high epoxide yield (99.8%) was obtained. In addition, IUST-1 can be easily separated by simple filtration and recycled five times successfully with a slight decrease in activity. This compound has some advantages such as high yield, short reaction time, and ease of reuse, which make it a suitable heterogeneous catalyst for the epoxidation of cyclooctene.

Novel Zn metal–organic framework with the thiazole sites for fast and efficient removal of heavy metal ions from water

Pollution of water by heavy metal ions such as Pb2+ and Hg2+ is considered as an important issue, because of the potential toxic effects these ions impose on environmental ecosystems and human health. A new Zn-based metal–organic framework, [Zn2(DPTTZ) (OBA)2] (IUST-2), was synthesized through a solvothermal method by the reaction of 2, 5-di (4- pyridyl) thiazolo [5, 4-d] thiazole ligand (DPTTZ), the “V-shape” 4,4'-oxybis (benzoic acid) ligand (OBA) and zinc nitrate (Zn(NO3)2·6H2O). This novel MOF has been characterized by several analysis techniques such as fourier transform infrared spectroscopy (FT-IR), elemental analysis (EA), powder x-ray diffraction (PXRD), thermogravimetry analysis (TGA), differential thermal analysis (DTA), field emission scanning electron microscopy (FE-SEM), Brunauer–Emmett–Teller (BET) surface area analysis and single-crystal X-ray diffraction (SXRD). This 3D MOF was tested for removing Pb2+ and Hg2+ ions from water. The factors that were investigated on the elimination of Pb2+ and Hg2+ ions were of pH, adsorption time, and the effect of initial ions concentration. According to the results, this particular Zn-MOF had significant performance in eliminating Pb2+ and Hg2+ ions from water with a removal efficiency of more than 97% and 87% within 3 min, respectively.

Half-sandwich iridium(III) and rhodium(III) complexes: synthesis, characterization and antifouling properties

The reaction of [(η5-C5Me5)MCl2]2 [M = Ir (1) or Rh (2)] with thiazole ligands (L) at room temperature [L = atz; 2-acetamidothiazole (3) or catz; 5-chloro-2-acetamidothiazole (4)] afforded iridium(III) and rhodium(III) complexes of the type [(η5-C5Me5)M(L)Cl2] [M = Ir; L = atz (5), ctz (6); M = Rh, L = atz (7), catz (8)]. Compounds were characterized by FTIR, NMR (1H and 13C) and mass spectroscopic data. The molecular structures of 5 and 6 have been determined by single-crystal X-ray diffraction. All the compounds were obtained as neutral complexes and the ligand is coordinated monodentate to the metal. The in vitro antibacterial activity of the compounds against ten marine fouling bacteria showed moderate to good activity against the tested marine fouling bacteria.

Synthesis and characterization of new metal complexes containing azo-indole moiety and anti-leukemia human (HL-60) study of its palladium (II) complex

The research included formation of (E)-2-(1H-indol-3yl)diazenyl)thiazole (HIDAT) ligand resulting from the reaction diazonium salt of 2-aminothiazole compound with indole compound. Azo dye ligand (HIDAT) and its complexes of the transition elements (cobalt, nickel, copper and palladium) were prepared and characterized by different technique such as elemental analysis (C.H.N.S), mass spectroscopy, 1H NMR, FT-IR, UV–Visible and magnetic measurements as well as molar conductivity. The HIDAT complexes were synthesized under molar ratio (1:2) of metal to ligand excepting Pd(II) complex prepared under mole ratio equal to 1:1. The HIDAT ligand presented significant ability to know pH for aqueous solutions. According to the infrared data, HIDAT dye functions as a bidentate ligand. The spectral studies were designated to octahedral geometry for the synthesized complexes excepting Pd complex was square planar. The cytotoxicity effect of palladium complex was demonstrated in human leukemia cell line HL-60 and HdFn healthy cells and the MTT results against HL-60 cells were more susceptible to the palladium complex's cytotoxicity than HdFn cells. The docking (MOE) study of the palladium complex against leukemia cancer protein (3s7s) has promising inhibition activity.

Magnetic nanoparticles supported a palladium bis(benzothiazole) complex: A novel efficient and recyclable catalyst for the synthesis of benzimidazoles and benzothiazoles from benzyl alcohol

In this work, the synthesis and characterization of a new heterogeneous catalyst by palladium (II) 3,5-bis(2-benzothiazolyl)pyridine supported on magnetic nanoparticles, Pd(II)Cl2[email protected], was investigated. In this regard, iron nanomagnets were functionalized with 3-chloropropyl trimethoxy silane, silica coated, and then thiazole ligand was efficiently attached to their surface, and finally, palladium (II) was bonded to their surface. The catalyst, Pd(II)Cl2[email protected], was characterized by DR UV–vis and FT-IR spectroscopic techniques, elemental analysis, FE-SEM, ICP, XRD and TGA. The heterogeneous catalyst was used for the reaction between derivatives of benzyl alcohol with 1,2-phenylenediamine or 2-aminothiophenol and synthesis of benzothiazoles and benzimidazoles. This newly synthesized catalyst easily reused and recycled numerous times without noteworthy loss of its catalytic activity.

Sonochemical synthesis of nanoparticles of Cd metal organic framework based on thiazole ligand as a new precursor for fabrication of cadmium sulfate nanoparticles

The current study reports the fabrication of a new Cd-MOF, [Cd (DPTTZ) (5-AIP)] (IUST-1), which was synthesized by the reaction of 5-Aminoisophthalic acid (5-AIP), 2, 5-di (pyridine-4-yl) thiazolo [5, 4-d] thiazole (DPTTZ) and cadmium nitrate tetrahydrate, via solvothermal and sonochemical methods. In comparison to the solvothermal route, which routinely takes 48 h, the ultrasound-assisted method improved faster synthesis with a reaction time of 1 h. Single crystal of IUST-1 was gained by solvothermal method and crystal structure characterized using X-ray crystallography and a range of spectroscopic techniques. The sonochemical method was utilized to synthesize IUST-1 nanoparticles as a precursor for the preparation of CdSO4·H2O nanoparticles. The calcination of IUST-1 at 600 °C under air atmosphere yields CdSO4·H2O nanoplates.

Spectroscopic and Thermal Studies of Some Palladium(II) Complexes with 2-amino-4-(4-subsistuted phenyl)thiazole Derivatives

Six new complexes of palladium(II) with a general formula [Pd(L)2Cl2], where L = 2-amino-4-(4-subsistuted phenyl)thiazole. The palladium complexes were prepared by the reaction of 2-amino-4-(4-subsistuted phenyl)thiazole ligands with with Bis(benzonitrile)palladium(II) dichloride in chloroform solvent at molar ratio Pd:L=1:2. The resulting complexes were characterized by the magnetic susceptibility, conductivity measurements, infrared, 1H NMR and the thermo gravimetric analysis. Elemental analyses, spectroscopic and another physical studies of the prepared palladium (II) complexes allowed structures to be proposed. The thermal properties of the prepared complexes indicated the all-decomposition steps and gave an insight about the stability of palladium(II) complexes. The physical analysis indicated that prepared ligands behaved as mono dental, bounding Pd(II) through the nitrogen atoms from the thiazole ring.

Efficient and recoverable novel pyranothiazol Pd (II), Cu (II) and Fe(III) catalysts in simple synthesis of polyfunctionalized pyrroles: Under mild conditions using ultrasonic irradiation

AbstractThree novel Pd (II), Cu (II), and Fe (III) complexes were prepared from thiazole ligand through bidentate chelating mode. Alternative spectral and analytical tools were applied to elucidate their structural and molecular formulae. This study was extended to investigate stability and stoichiometry of complexes in solution, using standard methods. In addition, the best atomic distribution within structural forms was obtained by Material Studio Package via the density functional theory (DFT) method. This computational study fed us with significant physical characteristics for differentiation. Also, crystal surface properties in the packing system were studied using the Crystal explorer program, to evaluate the extent of contact between surfaces. Computational data discriminate Pd (II)‐thiazole (HYHPd) complex by some physical features, which may be promising in the catalytic field. This complex was selected to play a catalytic function to synthesize polyfunctionalized pyrrole derivatives using ultrasonic irradiation in a one‐pot reaction. The catalyst was selected for this application based on the history of Pd (II) complexes and the properties expected theoretically. A condensation reaction for aromatic aldehyde, aromatic amine, acetylacetone, and nitromethane was carried out under mild reaction conditions by ultrasonic irradiation. All reaction conditions were optimized among that variable Lewis acid catalysts in comparison to our new complexes. HYHPd catalyst displayed superiority in overall trials with high yield, short time, and green conditions (solvent H2O/EtOH). Also, the recovery of hetero‐catalyst was succeeded and reused by the same efficiency up to five times after that the efficiency was reduced. The mechanism of action was proposed based on the ability of Pd (II) for adding extra‐bonds overzaxis and supported by theoretical aspects.

Synthesis and characterization of new thiazole-based Co(II) and Cu(II) complexes; therapeutic function of thiazole towards COVID-19 in comparing to current antivirals in treatment protocol

Two thiazole-based complexes were prepared from Co(II) and Cu(II) ions. The new ligand and its complexes were fully characterized by analytical and spectral techniques. The ligand behaved as a neutral tridentate in its keto-form towards the metals via O(8), O(10) and O(18) atoms. This was suggested based on the lower shift of υ(CHO), υ(CO)amide and υ(CO) vibrations. The electronic transitions in Co(II)-HL and Cu(II)-HL complexes displayed d-d- transitions which belong to 4T1g→4A2g(F) & 4T1g(F)→4T1g (P) and 2Eg →2T2g, in the two complexes, respectively. ESR spectrum of Cu(II)-HL complex displayed g-factor by the following order; g//(2.1740)>g⊥(2.0935)>2.0023, which agrees with octahedral geometry. The geometry optimization was executed by DFT/B3LYP method under valence double zeta polarized basis set (6–31G*), to confirm the structural forms and the mode of bonding. The orientation and the charges of O(8), O(10) and O(18) atoms, support the coordination of the ligand in its keto-form with the metal ions. Pharmacophore profiles were obtained regarding thiazole ligand and other recommended drugs (arbidol, avigan and idoxuridine) that used in treatment protocol of COVID-19 pandemic. Also, query was run in MolPort-library to obtain antiviral analogues, to broaden the search for an effective treatment. Three analogues were obtained for arbidol, avigan and idoxuridine drugs, which have the following numbers; MolPort-047-605-644, MolPort-004-768-508 and MolPort-028-750-709, respectively. Moreover, molecular docking was carried out to obtain all interaction details and rank the efficiency of thiazole compound versus the three antivirals in their interaction with the two COVID-19 proteins. The outcomes suggested the significant antiviral activity of idoxuridine and thiazole (enol-form), which not reach to eliminate the pandemic exactly. While, arbidol and avigan did not have an effective antiviral role, although they still used in COVID-19 treatment protocol.

Two metal complex derivatives of pyridine thiazole ligand: synthesis, characterization and biological activity

In this work, two new metal(II) complexes with ligand based on pyridine thiazolone group, [Zn(L)2(TsO)2]2DMF (1), {[Cd(L)(NO3)2H2O)]DMF}n (2) (where L = 4-(pyridin-4-yl)-2-(2-(pyridin-2- ylmethylene)hydrazinyl)thiazole), were prepared and characterized by physicochemical and spectroscopic methods. In addition, the structure of the complexes (1 and 2) was confirmed by single-crystal X-ray analysis. Complex 1 has a discrete monomeric structure where L acts as a bidentate agent coordinating the zinc(II) atom through pyridine nitrogen and thiazole nitrogen, while complex 2 consists of polymeric {[Cd(L)(NO3)2H2O)]DMF}n chains in which cadmium(II) atoms are linked by the bridging ligand. The in vitro antimicrobial and antitumor activities of the ligand and complexes (1 and 2) were evaluated against seven pathogenic bacterial strains and four human cancer cell lines, and the results showed that some compounds had absolute specificity for certain bacterial strains or cancer cell lines, which thus implied a good application prospect in pharmaceutical use.

Synthesis, crystal structures, DNA interactions, and antitumor activity of two new dinuclear copper(ii) complexes with thiazole ligand.

Two new dinuclear copper(ii) complexes, [Cu(ambt)2(cnba)4] (1) and [Cu(ambt)2(clba)4] (2) were synthesized with 2-amino-6-methoxybenzothiazole (ambt) as the main ligand. The structures of the two complexes were characterized by single-crystal XRD. The binding between CT-DNA (calf thymus DNA) and the complexes was evaluated by viscometry, electronic absorption, and fluorescence spectroscopy, and the binding constants were calculated using the Stern–Volmer equation. The complexes were intercalatively bound to CT-DNA, and [Cu(ambt)2(clba)4] having a greater binding constant than [Cu(ambt)2(cnba)4]. The two complexes had better antitumor properties against HepG2 (human hepatocellular carcinoma), A549 (human lung carcinoma), and HeLa (human cervical carcinoma) tumor cell lines than their respective ligands and cisplatin. Furthermore, [Cu(ambt)2(clba)4] had a stronger inhibitory ability on the three types of tumor cells than [Cu(ambt)2(cnba)4], which is congruent with the binding power of the complexes with DNA. Flow cytometry revealed that [Cu(ambt)2(cnba)4] and [Cu(ambt)2(clba)4] could trigger apoptosis or necrosis, arrest the HepG2 cell cycles, and cause G0/G1-phase cells to accumulate.

Anticancer activity, DNA binding and docking study of M(ii)-complexes (M = Zn, Cu and Ni) derived from a new pyrazine–thiazole ligand: synthesis, structure and DFT

A series of structurally related Zn(ii), Cu(ii) and Ni(ii) complexes of 4-(2-(2-(1-(pyrazin-2-yl)ethylidene)hydrazinyl)-thiazol-4-yl)-benzonitrile (PyztbH) have been synthesized and characterized by spectroscopy, single crystal X-ray crystallography and density functional theory (DFT).

Highly efficient Co@NCS nanosheet electrocatalyst for oxygen reduction reaction: An environment-friendly, low-cost and sustainable electrocatalyst

Rational, low cost, stable and more realistic synthesis of electrocatalysts comprising of earth abundant metals alterative to platinum-based catalysts is highly required for fuel cells. In this work, we demonstrate 2D nanosheet catalyst from metal organic frame works with zinc and 2-amino thiazole as organic ligand in presence of cobalt metal ions. The special bonding configurations of zinc with 2-amino thiazole ligand resulted in formation of 2D ZnxCo1-x(C3H4N2S) and the pyrolysis of 2D ZnxCo1-x(C3H4N2S) resulted in Co@NSC electrocatalyst. The electrochemical oxygen reduction reaction analysis of the Co@NSC catalyst reveals excellent activity with the half-wave potential of 0.88 V, similar to the commercial Pt/C catalyst. Moreover, Co@NSC catalyst also show the ultra-low HO2− formation bellow < 0.5 %, along with negligible degradation after 5000 potential cycles. In a alkaline fuel cell conditions, the Co@NCS catalyst delivered a power density of 37 mW cm-2.

Ruthenium(iii) complexes containing thiazole-based ligands that modulate amyloid-β aggregation.

Alzheimer's Disease (AD) is a devastating neurodegenerative disorder where one of the commonly observed pathological hallmarks is extracellular deposits of the peptide amyloid-β (Aβ). These deposits contain a high concentration of metals and initially presented a promising target for therapy; however it has become increasingly evident that the soluble form of the peptide is neurotoxic, not the amyloidogenic species. Metal-based therapeutics are uniquely suited to target soluble Aβ and have shown considerable promise to prevent the aggregation and induced cytotoxicity of the peptide in vitro. Herein, we have prepared a small series of derivatives of two promising Ru(iii) complexes NAMI-A (imidazolium [trans-RuCl4(1H-imidazole)(dimethyl sulfoxide-S)]) and PMRU20 (2-aminothiazolium [trans-RuCl4(2-aminothiazole)2]), to determine structure-activity relationships (SAR) for Ru(iii) therapeutics for AD. Using the three complementary methods of Thioflavin T fluorescence, dynamic light scattering (DLS), and transmission electron microscopy (TEM), it was determined that the symmetry around the metal center did not significantly impact the activity of the complexes, but rather the attached thiazole ligand(s) mitigated Aβ aggregation. Across both families of Ru(iii) complexes the determined SAR for the functional groups on the thiazole ligands to modulate Aβ aggregation were NH2 > CH3 > H. These results highlight the importance of secondary interactions between the metallotherapeutic and the Aβ peptide where hydrogen-bonding has the greatest impact on modulating Aβ aggregation.

Two Cu(II)-based coordination polymers: reduction activity on serum procalcitonin production and protective effect on children sepsis

In the current study, by applying the mixed-ligand approach, two new Cu(II)-based coordination polymers with the chemical formulae of {[Cu(Py2TTz)(BDC)](DMF)}n (1) and {[Cu2(Py2TTz)2(BDC)2]·2(DMF)·0.5(H2O)}n (2) are successfully prepared from a rigid N-donor linker 2,5-bis(4-pyridyl)thiazolo[5,4-d]thiazole (Py2TTz) and linear carboxylate ligands of 1,4-benzenedicarboxylic acid (H2BDC) under different reaction conditions. Then, the therapeutic activity of the compounds on the children sepsis is evaluated. Firstly, the percentage of lymphocyte apoptosis after treating with the compounds is measured with the V-FITC/PI staining assay. Next, the serum procalcitonin (PCT) content during sepsis after treating with the compounds is determined with the ELISA detection kit.

Synthesis, cytotoxicity and anti‐metastatic properties of new pyridyl–thiazole arene ruthenium(II) complexes

A series of novel ruthenium(II)–cymene complexes (1–8) containing substituted pyridyl–thiazole ligands, [Ru(η6‐p‐cymene)(L)Cl]Cl (L = N,N‐chelating derivatives), have been synthesized and characterized using elemental analysis, infrared, 1H NMR and 13C NMR spectroscopies and mass spectrometry. All these complexes not only display marked cytotoxicity in vitro against three different human cancer cell lines (HeLa, A549 and MDA‐MB‐231), but also exhibit promising anti‐metastatic activity at sub‐cytotoxic concentrations. Cell cycle analysis shows that the ruthenium(II) complex‐induced growth inhibition was mainly caused by S‐phase cell cycle arrest. Further protein level analysis suggests that compound 5 may exert antitumor activity via a p53‐independent mechanism.

(2-Deoxy-2-{[2-(2-pyridinyl-κN)-4-thiazolecarbonyl-κN3]amino}-α-d-glucopyranose)dichloropalladium(II) Methanol Solvate

A novel palladium(II) complex with a glycoconjugated 2-(2-pyridyl)thiazole ligand was synthesized. Single-crystal X-ray analysis revealed a packing structure that may be stabilized by hydrogen bonding between sugar moieties and between methanol (crystal solvent) and a sugar moiety.

Synthesis of a new pyridinyl thiazole ligand with hydrazone moiety and its cobalt(III) complex: X-ray crystallography, in vitro evaluation of antibacterial activity

The present work report the synthesis, structural characterization and in vitro antibacterial studies of (4-(4-methoxy phenyl)-2-(2-(1-pyridine-2-yl)ethylidene)hydrazinyl)thiazole bromide (HL·Br) and its cobalt(III) complex, [CoL2]ClO4. HL⋅Br crystallizes in a space group Pbca in a nearly planar structure and the crystal structure of complex shows a CoIIIN6 coordination geometry in which each L shows N,N,N-donor binding modes. Solution magnetic susceptibility measurement of [CoL2]ClO4 by modified Evan’s method confirms the low spin diamagnetic nature of the cobalt(III) complex. New compounds were screened for their antibacterial studies against gram positive bacteria including Staphylococcus aureus, Streptococcus faecalis and Bacillus subtilis and gram-negative bacteria including Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumonia and Proteus vulgaris. Both the compounds show very stronger growth inhibition activity against gram negative bacteria than gram positive bacteria. Present study shows that HL⋅Br has maximum antibacterial activity against E. coli (25±0.2mm) and S. typhi (28±0.7mm) at an MIC of 200µg/mL and 50µg/mL respectively, showing greater MIC values than the standard antibiotic ciprofloxacin (8µg/mL against E. coli and 10µg/mL against S. typhi).