Schiff Base Ligand Research Articles

Extracellular Matrix-Inspired Antibacterial Fibrous Hydrogels Containing Polyhexamethylene Biguanide and Gd3.

Traditional bulk hydrogels containing antibiotics or metal ions often fall short in effectively treating wound infections due to mechanical limitations, bacterial resistance, and potential cytotoxicity. To address these challenges, an extracellular matrix (ECM)-inspired antibacterial fibrous hydrogel featuring an anisotropic topological structure is developed that closely mimics the natural ECM environment. A novel antibacterial agent, PHMB-VAN-Gd (PVG), is synthesized by reacting polyhexamethylene biguanide (PHMB) with O-Vanillin (VAN) to form the Schiff base ligand PHMB-VAN (PV), followed by coordination with gadolinium ions (Gd3⁺). Employing silk fibroin (SF) as the matrix, the PVG complex is incorporated into fibrous hydrogels through electrospinning, generating structures that replicate the fibrous architecture of the ECM. The resulting SF-PVG fibrous hydrogels exhibited robust antibacterial activity, effectively inhibiting bacterial growth and biofilm formation. Furthermore, the aligned fiber orientation and substantial mechanical strength of these hydrogels facilitated cellular functions, promoting cell attachment and proliferation. This study underscores the significant potential of SF-PVG hydrogels for wound infection treatment.

Synthesis and characterization of novel Schiff base ligands and their Cu (II), Zn (II), Co (II), and Ni (II) complexes: DNA binding, antibacterial activity, and docking studies

In this paper, we describe the process of synthesizing and characterizing of cu (II), Ni (II), Co (II) and Zn (II) coordination compounds of 4,4’-((1E,1’E) -((4chloro-1,2phenylene) bis(azanylylidine)bis (methanylylidine)) bis (naphthalene-2-ol) [CAMD] Schiff base. Elemental analysis, molar conductance, spectral data (FT-IR, 1H NMR & 13C NMR, UV-visible, EPR, XRD and mass spectra), and thermogravimetric analysis (TGA) were used to establish their formation and validate their structures. All the complexes obtained as monomeric structure and the metal center moieties are four-coordinated with square planar geometry, according to the spectral analysis. Thermogravimetric analysis (TGA) was castoff to consider the decomposition of the complexes and Schiff base ligand. Herein, the calf thymus DNA (CT DNA) binding Goldfeather#12#kinships of complexes have been examined by UV–visible spectroscopy. All complexes interact with DNA through an intercalating way. In a series of dilution experiments with Kanamycin and Fluconazole as standards, the ligand and its metallic complexes (1-4) demonstrated antimicrobial activity against a variety of bacterial and fungal species, including Gram-positive (Staphylococcus aureus, Pseudomonas aeruginosa) and Gram-negative (Escherichia coli, Bacillus Subtilis, Salmonella Typhi), as well as fungal infections, as well as fungal infections, as well as fungal infections, as well as fungal infections, yeast infections, and yeast infections. The preliminary in vitro antimicrobial screening revealed that the newly synthesised Schiff base inhibits bacterial and fungal growth significantly, compared to standard drugs. Additionally in silico studies of molecular docking were also done for Schiff base ligand and its multiplexes in the active site of DNA Gyrase enzyme (PDB code:6TCK), demonstrating strong hydrogen bonding interactions of drug targets and can be used as antibacterial drugs angainst pathogens. The performance of complexes closely matched the reactivity order seen in in-vitro studies. Overall, the complexes are intriguing candidates for antimicrobial development. We intend to use these compounds in a therapeutic context. Synthesized substances were determined to be non-toxic after undergoing ADME/T analysis to assess their drug-likeness.

In vitro and in vivo studies of a decanuclear Ni(II) complex as a potential anti-breast cancer agent

A non-platinum-metal decanuclear complex [Ni10L4(CH3COO)8 (C2H5OH)8]·8(C2H5OH) (Ni10 complex) has been developed with a tri-dentate 2,3-dihydroxybenzaldehyde-2-aminophenol Schiff base ligand (H3L). Single crystal X-ray analysis reveals that the Ni10 complex displays a sandwich loaf-shaped decanuclear structure and its anticancer activity was evaluated. The cell cytotoxicity results indicating that the Ni10 complex is most effective to human breast cancer cells MDA-MB-231 and its mechanism were further investigated. Flow cytometry analysis showed that the Ni10 complex triggered cell cycle arrest and induced apoptosis of MDA-MB-231 cells. Western blot analysis of the changes of intracellular protein expression showed that Ni10 triggers MDA-MB-231 apoptosis through mitochondrial mediated apoptosis signaling pathways. In vivo experiments showed that the Ni10 complex significantly suppressed breast tumor growth with low toxicity against major organs in a nude mice model. The good treatment effect, low toxicity and pharmacological mechanisms of the decanuclear NiII complex may provide a clue for the research and development of non-platinum multinuclear based chemotherapeutic drugs.

Synthesis, single crystal investigations, DFT studies, biological activities, DNA cytotoxicity and molecular docking studies of copper(II) complex derived from the new o-vanillin Schiff base ligand

A novel Schiff base derivative, (E)-N’-(2-hydroxy-3-methoxybenzylidene)-2-phenylacetohydrazide (HMPH, H2L), and its Cu(II) complex were synthesized through the direct condensation of o-vanillin with phenylacetichydrazide in ethanol under reflux conditions. The synthesized ligand was identified usingelemental analysis, Fourier transform infrared (FTIR) and ultraviolet–visible (UV–Vis.) spectroscopy. The structures of HMPH (C16H16N2O3)2 and its Cu(II) complex [Cu(L)(H2O)]·H2O (C16H16N2CuO4·H2O) were analysed by single crystal X-ray diffraction technique. The X-ray diffraction results showed that HMPH crystallised in an orthorhombic Pca21 space group with a Z value of 8, while [Cu(L)(H2O)]·H2O crystallised in a monoclinic C 2/c space group with the same z value. The Cu(II) ion is coordinated to the acetohydrazide ligands via hydrazone nitrogen, aceto oxygen (N(2) and O(1)) and hydroxyl O(2) atoms. In addition to the single crystal structures of HMPH and [Cu(L)(H2O)]·H2O, the optimised molecular structures, molecular electrostatic potential meps, molecular orbital energy values, and interactions between DNA bases and molecular structures are determined by DFT/B3LYP/6-311G(d, p) for HMPH and DFT/B3LYP/LanL2DZ for [Cu(L)(H2O)]·H2O. The copper complex was found to be more potent than the organic ligand in terms of antimicrobial activity, with a strong anti-biofilm effect even at low MIC values. The cytotoxicity of the synthesized compounds was investigated on MDA-MB-231 cell lines. The [Cu(L)(H2O)]·H2O complex was found to be more lethal than the HMPH ligand. Furthermore, molecular docking studies of HMPH and [Cu(L)(H2O)]·H2O with P. aeruginosa ATCC27853 (PDB ID: 6P8U) were presented to explain the observed antibacterial activity and the mechanism-of-action.

Polymeric Schiff base containing phenylhydrazine and 2-thiobarbituric acid: Synthesis, characterization, antibacterial and antifungal studies

Polymeric Schiff base ligand (MFT) derived from 2-hydroxyacetophenone, phenylhydrazine, formaldehyde, and 2-thiobarbituric acid was synthesized via condensation reaction. The synthesized MFT ligand was complexed with the metal acetates of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) to form a polymeric Schiff base-metal complexes. The ligand and its metal polychelates were characterized by Fourier transform infra red (FT-IR), Ultraviolet-visible spectroscopy (UV-vis.), X-ray diffraction (XRD), Proton nuclear magnetic resonance spectroscopy (1H NMR), Thermogravimetric analysis (TGA), Scanning electron microscopy (SEM), Energy dispersive X-ray spectroscopy (EDX) and Electron paramagnetic resonance spectroscopy (EPR). The EPR spectrum of MFT-Cu(II) supported a distorted octahedral or square-planar geometry. The synthesized materials were also screened against bacterial (S. aureaus, S. mutans, B. cereus, S. pyrogenes, S. viridans, S. epidermids, C. xerosis, E. coli, K. pneumonia, P. vulgaris, P. aeruginosa) and fungal strains (A. niger, F. oxysporum, and A. oryzea). Moreover, the MFT-Zn(II) complex have demonstrated good thermal stability, as well as strong antibacterial and antifungal activities compared to the ligand and other metal polychelates.

Bidentate [C,N] and Tridentate [C,N,S] Palladium Cyclometallated Complexes as Pre-Catalysts in Cross-Coupling Reactions.

Treatment of halide substituted bidentate [C,N] and tridentate [C,N,S] Schiff base ligands with palladium(II) acetate or with lithium tetrachloropalladate, as appropriate, afforded through C-H activation of the organic ligand, the dinuclear (1 a, 1 b) and mononuclear (1 c, 1 d, 1 e) palladacycles, respectively. Reaction of the μ-acetate dinuclear complexes with aqueous sodium chloride in a metathesis process, gave the μ-chloride dinuclear complexes (2 a, 2 b). Treatment of the latter with triphenylphosphine or with bis(diphenylphosphino)methane (dppm)/ammonium hexafluorophosphate in complex/ phosphine 1 : 2 ratio, gave the phosphine derivatives (3 a, 3 b, 4 a, 4 b). Reaction of 1 c and of 1 e with triphenylphosphine/silver perchlorate and dppm/silver perchlorate, respectively, gave compounds 2 c and 2 e with removal of the chloride ligand by precipitation of the silver halide. The compounds were characterized by microanalysis (CHN), IR and 1H and 31P{1H} NMR spectroscopy. The crystal structures of three complexes, 4 a, 1 c and 1 e were studied by single-crystal X-ray diffraction. Furthermore, the performance of the palladacycles were tested as pre-catalysts, namely Suzuki-Miyaura cross-coupling reaction and those furnishing the better results are also reported.

Synthesis of metal-based biologically active agents from ONO-donor Schiff base ligand

Synthesis of metal-based biologically active agents from ONO-donor Schiff base ligand

The thermal behavior of silicone-based composite materials and the assessment of the gases that result from the thermal degradation process

A series of composite materials were prepared on the basis of polydimethylsiloxane (PDMS) having different siloxane functionality, filled with two types of metal complexes containing siloxane segment, derived from condensation of 1,3-bis(3-aminopropyl)tetramethyldisiloxane with 3,5-di-tert-butyl-2-hydroxibenzaldehyde and 5-chloro-2-hydroxibenzaldehyde. The main objective of the proposed study is to introduce transition metal complexes with Schiff-base ligands that contain siloxane spacers into the PDMS matrix and examine the effect these complexes have on thermal stability. We investigated the produced gases using thermogravimetry coupled with FTIR and MS in order to analyze the thermal stability and degradation pathways of a variety of silicone composite materials.

Circularly Polarized Phosphorescence Properties of Binuclear Cyclometalated Platinum(II) Complexes Bearing Axially Chiral Schiff-Base Ligands.

The synthesis, structure, and circularly polarized phosphorescence (CPP) properties of axially chiral cyclometalated binuclear platinum(II) complexes were described. A series of optically pure binuclear platinum(II) complexes were synthesized in five steps from commercially available (R)- or (S)-1,1'-bi-2-naphthol (BINOL) as starting materials. Their three-dimensional molecular structures and square-planar coordination geometries were elucidated from X-ray diffraction and 2D NMR analysis. The complexes were found to exhibit red- to near-infrared photoluminescence in solution and in the solid state. Furthermore, dilute DMSO solutions of the enantiopure samples showed red CPP with relatively high luminescence dissymmetry factor (glum) values. Density functional theory (DFT) calculations were conducted to examine their three-dimensional molecular conformations and photophysical properties.

Synthesis, Spectral Characterization, Antimicrobial Activity, DFT Calculations, Molecular Docking and ADME Studies of Novel Schiff Base Co(II), Ni(II), Cu(II) and Zn(II) Complexes Derived from 4-nitro-ortho-phenylenediamine.

A condensation reaction was carried out between 4-nitro-ortho-phenylenediamine and 5-bromosalicyaldehyde to synthesize a novel Schiff base ligand 2,2'-[(1E,1'E)-(4-nitro-1,2-phenylene) bis (azaneylylidene) bis (methaneylylidene)] bis (4-bromophenol) [NB] in the current investigation. This was followed by the synthesis of metallic complexes comprising the Co(II), Ni(II), Cu(II) and Zn(II) transition metal ions. A hexadentate environment encircling metal complexes was corroborated by the results of varied spectroscopic methods that were employed to unravel the structure of the ligand and metal complexes. The Tauc's plot and Urbach energy were utilized for quantifying the optical energy band gap to provide insight into optical characteristics. The Coats-Redfern method of thermal analysis was implemented to do the kinetic and thermodynamic calculations. Furthermore, DFT studies were performed to predict geometrical structures and the stability of the compounds. Thorough investigation to evaluate their biological efficacies, docking studies was executed against COVID-19 main protease (PDB-7VAH), Dengue virus NS2B/NS3 protease (PDB-2FOM) and Mycobacterium Tuberculosis (PDB-5AF3). Apart from this, in silico ADMET studies were also accomplished for elucidation of drug likeness characteristics and the results attained disclose the significant proficiency of synthesized compounds. Besides this, antimicrobial studies were assessed with different microbial strains and result validates cobalt and zinc complexes as most potent against the selected bacterial and fungal strains.

Preparation and Antifungal Properties of Cyclopropyl Derivatives of 3-Aminoquinazolin-4(3H)-one and Salicylal Schiff Base Nickel(II) Chelate Complex

N-substituted 2-cyclopropyl-3-R-quinazoline-4()-ones [R: NH2 (1), N=CH(2-hydroxyphenyl) (2)] and Ni(II) chelate compound of 2-cyclopropyl-3-[(Z)-(2-hydroxybenzylidene)amino]quinazoline-4(3H)-one (3) were synthesized and their structures and properties were characterized using X-ray diffraction data, computational optimization, 1H and 13C NMR, IR spectroscopy, and diffuse reflectance spectra. Compounds 1 and 2 are monoclinic (space group P21/n). Unit cell parameters (a, b, c) are 9.2529; 4.7246; 22.3460 Å and 10.2811; 4.6959; 30.972 Å for 1 and 2, respectively. Nickel(II) chelate compound crystallizes in an orthorhombic crystal system (space group Pbca). Unit cell parameters (a, b, c) for 3 are 26.5010; 14.8791; 8.904975 Å, respectively. Schiff base 2 in the crystalline state exhibits two rotary isomers in a molar ratio of 1:3, among which only a minor component as a bidentate ligand can form compound 3 with Ni(II) ion. Nickel(II) ion in 3 is coordinated by N donor atoms and deprotonated O atoms of Schiff base ligands to form square-planar chelate node NiN2O2. All synthesized compounds revealed high antifungal activity against bread mold (Mucor mucedo).

Synthesis, Crystal Structures, Antimicrobial Activity, and Acute Toxicity Evaluation of Chiral Zn(II) Schiff Base Complexes

Four mononuclear bioefficient zinc coordination complexes [Zn(NN)3](ClO4)2 (A–D) involving chiral bidentate Schiff base ligands have been synthesized and characterized by IR, 1H, and 13C NMR spectroscopy and mass spectrometry. X-ray crystal structures of three of the zinc complexes revealed that the zinc metal ion is hexacoordinated, exhibiting a distorted octahedral geometry where both the nitrogen atoms (NN = pyridyl and imine) of imines are coordinated to the central zinc ion. The isolated zinc complexes were evaluated for their antimicrobial activity in vitro against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus, displaying varying levels of growth inhibition. An acute toxicity test conducted using Artemia salina and Swiss albino mice showed that the zinc complexes A–D were non-toxic towards A. salina at concentrations below 414, 564, 350, and 385 µM, respectively, and did not affect liver biochemical parameters, although pyknosis was induced in hepatocytes of the treated mice.

A dual vis-NIR emissive ytterbium(III) complex with potential application in OLED devices with optical determination of the internal temperature

A dual-emissive ytterbium complex with a pyrene-substituted Schiff base ligand was synthesized and characterized. The complex exhibits both visible and near-infrared (NIR) emissions, with the emission bands ratio showing a significant temperature dependence in the range of 77–420 K. This feature makes the complex suitable for luminescent thermometry applications including inside of the organic light-emitting diode (OLEDs) emission layer (EML). Several heterostructures with different hole transport layers and different thicknesses of the EML were tested. The OLED1 with thinner EML demonstrate external current efficiency (ECE) up to 30 μW/W while electroluminescence spectra contain both vis and NIR emission bands that make it possible to measure EML temperature which reach up to 77–114 °C.

Eco-friendly Synthesis, Characterization, and Antimicrobial Evaluation of Transition Metal (II) Complexes with Thiophene-Derived Tridentate (S N N Donor) Heterocyclic Schiff Base Ligand

Eco-friendly Synthesis, Characterization, and Antimicrobial Evaluation of Transition Metal (II) Complexes with Thiophene-Derived Tridentate (S N N Donor) Heterocyclic Schiff Base Ligand

Synthesis of derived Cu(II) complex from Schiff base of Vitamin B6 and antihypertensive hydralazine: DNA interaction, biological application and molecular docking studies

A novel Schiff base ligand (E)-5-(hydroxymethyl)-2-methyl-4-((2-(phthalazin-1-yl)hydrazineylidene)methyl)pyridin-3-ol was synthesized through the condensation of antihypertensive hydralazine and Pyridoxal (Vitamin B6) ligands. This fabricated Schiff base (L) was a precursor for developing a unique Cu(II) complex. TheSchiff base ligand and Cu(II) complex structureswere characterized using various analytical tools, including IR, UV–Vis Spectroscopy and NMR. An octahedron geometry of this complex was proposed for the assigned molecular formula [Cu(L)2].3H2O. The molecular structures of theSchiff base ligand and its Cu(II) complex have been optimized using the B3LYP functional and the 6-311G++(d,p) basis set. Investigating the interaction of this prepared Cu(II) complex with calf thymus DNA (CT-DNA) molecules was operated using UV–Vis spectrophotometry, viscosity measurement, electrochemical studies, gel electrophoresis, and molecular docking. In vitro cytotoxicity was conducted using the MTT assay on four human tumor cell lines including hepatocellular carcinoma, estrogen-dependent breast cancer, melanoma, triple-negative breast cancer as well as healthy human skin fibroblasts.

Qualitative and Quantitative Luminescence Detection of 2,6-Dipicolinic Acid and Levofloxacin Based on a High-Nuclearity Eu(III) Nanomolecular Sensor.

Rapid and accurate testing of 2,6-dipicolinic acid (DPA) and levofloxacin (LFX) has been attracting much attention due to the fact that the former is an important biomarker of anthrax spores and the latter is a third-generation fluoroquinolone drug and has been recognized as an important environmental pollutant. Herein, we report the preparation of a 13-metal Eu(III) nanomolecular sensor (molecular sizes: 2.0 × 2.4 × 3.2 nm) bearing a new flexible Schiff base ligand for luminescence testing of DPA and LFX with high selectivity and sensitivity. The rapid enhancement of the Eu(III) luminescence of 1 caused by DPA and LFX is expressed by fitting equation I615nm = k × [C] + a, which can be used to quantitatively detect DPA and LFX concentrations in CH3CN, fetal calf serum (FCS), and a real drug. The response times of 1 to DPA and LFX are less than ten seconds, with detection limits as low as 3.78 × 10-2 to 2.71 nM. The test strips containing 1, as well as 1@SA films, can be used to qualitatively detect DPA and LFX by the color changes under the irradiation of UV light.

Comparative Analysis of Tetravalent Actinide Schiff Base Complexes: Influence of Donor and Ligand Backbone on Molecular Geometry and Metal Binding.

A series of isostructural early actinide AnIV complexes was synthesized in order to investigate the influence of a conjugated framework in the ligand backbone on An bonding. Therefore, the AnIV complexes [An(pyrophen)2] (An = Th, U, Np, and Pu) with the pure N-donor ligand bis(2-pyrrolecarbonylaldehyde)-o-phenylenediamine referred to as pyrophen, were synthesized and characterized. Solid state analysis via single-crystal X-ray diffraction (SC-XRD) reveals two sets of ligands binding in an almost orthogonal arrangement to the actinide center. For the larger actinides Th and U, the coordination sphere allows for additional coordination by a solvent molecule. Nuclear magnetic resonance spectroscopy (NMR) studies show the presence of highly symmetrical complexes in solution in good agreement with the solvent-free solid structures. While SC-XRD suggests mainly ionic binding, an analysis of paramagnetic NMR contributions and quantum chemical bond analysis hint towards significant covalency in the U, Np, and Pu compounds. This series of An complexes allowed for a thorough structural and theoretical comparison of a conjugated system to a closely related N-donor ligand (pyren)[1] as well as to the mixed N,O Schiff base ligands salophen (conjugated) and salen (non-conjugated).

Antifungal, antibacterial and DNA binding profile of three novel Zn(II), Cd(II) and Hg(II) complexes of a pyrazole-based Schiff-base ligand: Synthesis, crystal structures, DFT studies and spectroscopic investigation

Three new mononuclear Zn(II), Cd(II) and Hg(II) complexes, [Zn(MPAFA)3](ClO4)2 (1), [Cd(MPAFA)3](ClO4)2 (2) and [Hg(MPAFA)Cl2] (3) of a pyrazole based ‘NN’ bidentate Schiff-base ligand, N-(furan-2-ylmethyl)-1-(5-methyl-1H-pyrazol-3-yl)methanimine, (MPAFA) (L) were synthesized and characterized by elemental analyses, conductance, IR, NMR (1H and 13C), UV-Vis and fluorescence spectral techniques. Molar conductance measurements identified both 1 and 2 as 1:2 electrolytes, while 3 as a non-electrolyte. Single crystal X-ray diffraction studies recognized complexes 1 and 2 as distorted octahedral species with a N6 donor set. The presence of strong non-covalent interactions, such as intramolecular hydrogen bonding and π···π stacking within the complex molecules has been found to contribute to the enhanced stability of the complexes. In absence of single crystal, the structural feature of complex 3 has been confirmed by DFT studies and it has been found to adopt a distorted square-planar geometry with a N2Cl2 coordination. DFT calculations have also been conducted for 1 and 2. The TD-DFT absorption spectral studies supported the experimental results, indicating that the simulated peaks aligned reasonably well with the experimentally resolved peaks. Furthermore, the ligand and all its complexes exhibited effective antifungal activity against Colletotrichum siamense (AP1) and Fusarium equisetum (F.E) fungi. They also displayed promising antibacterial activity against both the gram-negative bacterium Klebsiella sp. (KS) and the gram-positive bacterium Methicillin-resistant Staphylococcus aureus (MRSA). The binding interactions of 1, 2 and 3 with calf-thymus DNA (CT-DNA) have also been studied using a combination of UV-Vis and fluorescence spectroscopic methods.

Homobimetallic Ruthenium(II) Complexes Catalysed Selective Transfer Hydrogenation of Aldehydes in Water.

Herein we report chemoselective transfer hydrogenation (TH) of aldehydes in aqueous medium using a series of homobimetallic Ru(II) catalysts. Two homobimetallic complexes (Ru1 and Ru3) and one monometallic complex (Ru2) have been employed in the catalytic reduction of aldehydes. Bimetallic complex [(p-cymene)2(RuCl)2L3] (Ru3) is obtained from the reaction of Schiff base ligand 2,2'-((1E,1'E)-((3,3',5,5'-tetraisopropyl-[1,1'-biphenyl]-4,4'diyl)bis(azaneylylidene))bis(methaneylylidene))bis(4-bromophenol) (H2L3) and characterized by various spectroscopic and analytical techniques. The use of formic acid/formate buffer as the hydride source and a catalyst loading of 0.01 mol% of Ru1 or Ru3 resulted in the conversion of various aldehydes to the corresponding alcohols in good to excellent yield. This method is very efficient for selective reduction of aldehydes in the presence of other reducible functional groups. A loading of 0.0001 mol% of Ru1 catalyst is sufficient to achieve a turnover frequency (TOF) of 5.5× 105 h-1. Furthermore, the catalyst can been recycled and reused for six consecutives cycles without sacrificing the efficiency. A comparison of results obtained between bimetallic and monometallic complexes offers valuable insights into the distinct reactivity patterns of the bimetallic complexes, presumably originating from a cooperative effect. We have explored the mechanistic pathway using DFT methods.

Well Defined Phosphine Free Ni-Catalyzed Dehydrogenation of Secondary Alcohols for the Synthesis of Ketones and Ketazines.

In this work, we unveil a novel synthesis of bench stable Ni (II) complexes supported by tetradentate Schiff-base ligands and the complexes were devoid of any phosphine or phosphine-based ligand. These Ni-complexes were successfully applied for the dehydrogenation of secondary alcohols for ketone and ketazine syntheses. Secondary alcohols with different functional groups were well tolerated during catalytic cycle. Moreover, we successfully extended this protocol for the synthesis of biologically significant ketones and ketazines. On the basis of various control experiments, probable reaction pathway was proposed and an acceptorless alcohol dehydrogenation mechanism was suggested.