Isatin Hydrazones Research Articles

Synthesis and DFT Calculation of Hg2+ Fluorescence Chemosensor Based on a New Hybrid Organic–Inorganic Nanoporous Material of SBA‐Pr‐Is‐Hy

ABSTRACTIn this study, a new hybrid organic–inorganic nanoporous material of SBA‐Pr‐Is‐Hy was synthesized by modification of SBA‐15 with (3‐chloropropyl)triethoxysilane to get SBA‐Pr‐Cl, which was reacted with isatin hydrazone to obtain SBA‐Pr‐Is‐Hy. This new compound was characterized by different FT‐IR, TGA, SEM, EDX, XRD, and BET techniques. Fluorescence spectroscopy of SBA‐Pr‐Is‐Hy was studied. According to the results, it can detect the Hg2+ ion with a detection limit of 3.5 × 10−7 M among the other metal cations. Hg2+ ion is toxic and dangerous; it is very important to identify it with simple and efficient methods. DFT calculations, including molecular electrostatic potential (MEP) surface, geometry optimization, HOMO–LUMO analysis, and quantum chemical descriptors, were investigated utilizing the B3LYP/6‐311G(d,p)/LANL2DZ method. The DFT calculation verifies the experimental mechanism of interaction between the ligand and Hg2+.

Pseudo-three-component spiro[dihydrofuran-2,3′-oxindoles] synthesis: <i>in situ</i> generation of diazooxindole

Upon reaction with N -substituted pyrroloquinoxalinetriones, isatin hydrazone is oxidized to diazooxindole and enters into a formal [4+1] cycloaddition reaction with N -substituted pyrroloquinoxalinetriones to form compounds containing a spiro[dihydrofuran-2,3′-oxindole] fragment, which is interesting for medicinal chemistry. The reaction of diazooxindoles with N -unsubstituted pyrroloquinoxalinetriones afforded analogous substituted spiro[dihydrofuran-2,3′-oxindoles]. The resulting compounds have moderate antimicrobial activity.

Biologically Active Symmetric and Asymmetric Dicationic Bis(isatin hydrazones): What is Better―To Complicate or Simplify the Spacer?

Biologically Active Symmetric and Asymmetric Dicationic Bis(isatin hydrazones): What is Better―To Complicate or Simplify the Spacer?

Metal ion induced changes in the structure of Schiff base hydrazone chelates and their reactivity effect on catalytic benzyl alcohol oxidation and biological assays

Divalent para-magnetic copper(II) and iron(II) chelates of Schiff base isatin hydrazone derivative are synthesized and characterized, as CuLONOCl and Fe(LONO)2, respectively. With different stoichiometric ratios (molar ratios) of 1: 1 and 1: 2 of Cu2+ or Fe2+ ion to the ligand (HLONO), both chelates are prepared with distorted square planar and octahedral structures, respectively. The catalytic action of both CuLONOCl and Fe(LONO)2 is examined in the homogeneous oxidation benzyl alcohol using H2O2 to benzaldehyde (the selective product). All studied compounds involved in the antimicrobial and anticancer studies and also against the ctDNA. Catalytically, their optimization is progressed within the influence of temperature, time and solvent. CuLONOCl manifests an optimized catalytic atmosphere for the yield percentage of benzaldehyde (92%) at 70°C after 4 h, whereas, Fe(LONO)2 displays less catalytic action with less yield (88%) after 3 h at 90°C. The variation in their structure and central metal ion assign to understand the difference in their catalytic potentials. The proposed mechanism for the oxygenation process based on electron-oxygen transfer steps.In the biological studies, CuLONOCl displays more action against some common microbes (bacteria and fungi) and cancers growth compared to that of Fe(LONO)2. The role of M2+ ion in its complex and its geometries illustrate their utility in such biological studies within Tweedy's chelation theory. Their interaction with ctDNA (calf thymus DNA) is aimed to represent the impact of Cu2+ and Fe2+ ions in the complexing agents with the influence of their structures through the changes and shifts of spectroscopic the viscosity investigations. Their interaction with ctDNA is illustrated spectroscopically according to the derived values of the binding constants, Kb, and the negative Gibbs’ free energy, ΔGb≠.

Promoted catalytic potential in sulfides oxidation and biological screening of green Pd (II) and Co (II) complexes of salicylidene isatin hydrazone ligand

Mononucleating complexes of isatin hydrazone sodium sulfonate ligand (HLn) with palladium (II) and cobalt (II) ions: The complexes were synthesized within 1:1 and 2:1 molar ratio of HLn with Pd2+and Co2+ion in PdLn and Co (Ln)2, respectively. The catalytic reactivity of both complexes was examined in the oxidation of sulfides (diphenyl sulfide, dps, and methylphenyl sulfide, mps) using hydrogen peroxide under aerobic conditions. Oxoproducts, dipheylsufoxide, dpo, and methyl phenyl sulfoxide, mpo, are the chemoselective products with detection of large amounts of the unselective further oxidation products of dioxoproducts (dipheylsufone, dpn, and methylphenyl sulfone, mpn). The homogenous catalyst of Co (Ln)2revealed more efficient action compared to that of PdLn depending on the high electrochemical reversible potential of the central metal ion in the catalytic reaction within the electron and/or oxygen transfer system.Exploring the importance of the M2+ion in the coordinated ligand, the bio‐reactivity of HLn, PdLn, and Co (Ln)2was illustrated within some commonly well‐known bacteria and fungi strains. Additionally, they were involved as anticancer reagents against some human cancer cell lines in vitro. Both metal complexes presented high inhibited action versus the growth of the studied microorganism and cancer. The interaction effect of Pd2+and Co2+ions in their pincer complexes was tested with calf thymus DNA spectroscopically and via the viscosity changes.

Polar and nonpolar iron (II) complexes of isatin hydrazone derivatives as effective catalysts in oxidation reactions and their antimicrobial and anticancer activities

Two iron (II) complexes of various derivatives (polar with 5‐sodium sulfoante group and nonpolar with di‐tertbutyl groups, HLSO3Na and HLDBu, respectively) of isatin hydrazones were synthesized within 1:2 molar ratios of Fe2+ion to the isatin hydrazone ligand giving Fe (LSO3Na)2and Fe (LDBu)2, respectively. The polar and nonpolar isatin hydrazone derivatives behaved asO,N,O‐tridentate pincer chelating agents with Fe2+ions. The variation in polarity of the two Fe2+‐complexes controlled their catalytic action in the oxidation of alcohols usingtBuOOH (tert‐butyl hydroperoxide). The polar catalyst showed more enhanced catalytic behavior than that of the nonpolar one. The optimized conditions for Fe (LDBu)2was found to be better at 70°C after 4 h with 86% of benzaldehyde than that with Fe (LSO3Na)2(at 90°C after 2 h with 84% of benzaldehyde). Their kinetic studies were used to derive the thermodynamic parameters ofEaand ΔG#for the catalytic processes.Biologically, based on their high reactivity toward some bacterial and fungal strains and some human cancer cell lines, the calf thymus‐DNA (ctDNA) interaction of the current compounds were studied. The nonpolar Fe2+‐complex (Fe (LDBu)2) assigned more reactivity withctDNA more than that of the polar reagent (Fe (LSO3Na)2) and also more than that of their uncoordinated ligands depending on their lipophilicity. Their reactivities towardctDNA was established spectrophotometrically and within the changes in the DNA solution viscosity. The binding strength was evaluated with the magnitudes of the binding constant (Kb = 3.03, 3.21, 9.79, and 11.51 × 108 mol−1 dm3for HLDBu, HLSO3Na, Fe (LDBu)2, and Fe (LSO3Na)2, respectively), which supported by the Gibbs' free energy values −3.12, −31.42, −34.18, and −34.58 kJ mol−1, respectively.

Novel isatin-based complexes of Mn(II) and Cu(II) ions: Characterization, homogeneous catalysts for sulfides oxidation, bioactivity screening and theoretical implementations via DFT and pharmacokinetic studies

Two mononuclear manganese(II) and copper(II) complexes were prepared from the coordination of 3,5-di-tert-butyl isatin hydrazone derivative (HLOEt) with either 2 : 1 or 1 : 1 M ratio for Mn(II) or Cu(II) ion, within octahedral and square planar geometries (Mn(LOEt)2 and CuLOEt), respectively. The catalytic potential of both M(II)-complexes was evaluated in the oxidation of sulfides, i.e. diphenyl sulfide (DPS) and methylphenyl sulfide (MPS), by tert-butyl hydroperoxide (tBuOOH) in acetonitrile. The chemo- and regio-selectivity of the redox system was determined by formation of mono-oxoproducts, diphenyl sufoxide (DPO) and methylphenyl sulfoxide (MPO), with detection of further products of mainly dioxide-product of diphenyl sufone (DPN) and methylphenyl sulfone (MPN). With Mn(LOEt)2, the reaction gave 55 and 54% (ee, 79% of S and 21% of R) yields of DPO and MPO, respectively. The catalytic activity of CuLOEt was slightly more progressed than that of Mn(LOEt)2, which awarded 52 and 56% (ee, 83% of S and 17% of R) percentages of DPO and MPO, respectively. The higher catalytic reactivity of CuLOEt catalyst was based on their geometrical structures to facilitate the approach of the oxidant and substrate in the redox systems. Their reactivity was studied against some common strains of bacteria and fungi. Moreover, their bio-potential was explored as anticancer reagents versus some human cancer cell lines. Both M(II)-complexes exhibited high biological action against the microorganism and cancer growth. The effect of M(II) ion in thier complexes was examined through the interaction of with ctDNA (calf thymus DNA). Such interaction was tested spectroscopically and via changes in ctDNA viscosity. The reactivity was measured by the binding constant values (Kb = 3.19, 13.85 and 15.39 × 108 mol−1 dm3 for HLOEt, Mn(LOEt)2 and CuLOEt, respectively), which reflects high interaction with ctDNA. Furthermore, the Gibbs’ free energy values supported their high potential against ctNDA, with −1.24, −1.36 and −1.37 kJ mol−1, respectively. Furthermore, HLOEt, CuLOEt and Mn(LOEt)2 were optimized by DFT/B3LYP method under either of 6-31G* of SDD basis set to estimate the essential physical characteristics. On the other hand, in silico approaches were utilized through online software as Swiss-ADME and Pharmacophore beside the molecular docking program. Pharmacokinetic, drug-likeness and the interaction with iso-enzymes were investigated for CuLOEt complex versus receptor tyrosine kinase (2a91, 2src) and human oestrogen receptor (2iok, 4rj3), as well as, liver cancer cells via 6jxt and (PCSK9) Proprotein Convertase Subtilisin/Kexin type 9 (4nmx, 4ne9). Only the proteins 4nmx and 4ne9 from liver cancer cells were found to be effectively inhibited by CuLOEt complex.

Synthesis and diverse biological activity profile of triethylammonium isatin-3-hydrazones.

A series of biorelevant triethylammonium isatin hydrazones containing various substituents in the aromatic fragment have been synthesized. Their structure and composition were confirmed by NMR- and IR-spectroscopies, mass-spectrometry and elemental analysis. It was found that some representatives show activity against Staphylococcus aureus and Bacillus cereus higher or at the level of norfloxacin, including methicillin-resistant Staphylococcus aureus strains. The study also showed low hemo- and cytotoxicity (Chang Liver) and high antiaggregatory and anticoagulant activity of these compounds. The high potential of new ammonium isatin-3-acylhydrazones in the search for antimicrobial activity against phytopathogens of bacterial and fungal nature has been shown for the first time.

A quick microwave preparation of isatin hydrazone schiff base conjugated organosilicon compounds: Exploration of their antibacterial, antifungal, and antioxidative potentials

In the current study, five isatin hydrazone schiff base linked acetylinic scaffolds have been synthesized via condensation reaction of isatin hydrazone with aldehydic groups. In order to identify the structure characteristics of the prepared hydrazone derivatives, IR, 1H and 13C NMR spectroscopy, elemental analysis and X- ray crystallography were carried out. The antibacterial and antifungal activity of the derivatives against six bacterial strains (S. aureus, S. Pyogenes, E.coli, V. cholera, L. monocytogens and H.influenza) and seven fungal strains (C. glabrata,C. parapsilosis, C. krusei, C. albicans, C. tropicalis, C. keyfer, and C. neoformans) have been evaluated. All the compounds showed potent antibacterial activity with IC50 ≈ 7.81 µM against H. influenza while the activity against fungal strains was less. Compounds a and c also had IC50 ≈ 7.81 µM against S. Pyogens. Furthermore, the results of total antioxidant activity of hydrazone derivatives, expressed in terms of the ascorbic acid (mM) equivalents per mg of sample, indicates their superior bioactivity. These studies suggested that the istain hydrazone functionalized acetylenic derivatives could be an ideal biomaterial for antibacterial, antifungal and antioxidant applications. Besides this, these derivatives were transformed into isatin hydrazone appended 1,2,3 triazole based organotriethoxysilanes and their reaction conditions were optimised

Novel thiomorpholine tethered isatin hydrazones as potential inhibitors of resistant Mycobacterium tuberculosis

Novel chemotherapeutic agents against multidrug resistant-tuberculosis (MDR-TB) are urgently needed at this juncture to save the life of TB-infected patients. In this work, we have synthesized and characterized novel isatin hydrazones 4(a-o) and their thiomorpholine tethered analogues 5(a-o). All the synthesized compounds were initially screened for their anti-mycobacterial activity against the H37Rv strain of Mycobacterium tuberculosis (MTB) under level-I testing. Remarkably, five compounds 4f, 4h, 4n, 5f and 5m (IC50 = 1.9 µM to 9.8 µM) were found to be most active, with 4f (IC50 = 1.9 µM) indicating highest inhibition of H37Rv. These compounds were further evaluated at level-II testing against the five drug-resistant strains such as isoniazid-resistant strains (INH-R1 and INH-R2), rifampicin-resistant strains (RIF-R1 and RIF-R2) and fluoroquinolone-resistant strain (FQ-R1) of MTB. Interestingly, 4f and 5f emerged as the most potent compounds with IC50 of 3.6 µM and 1.9 µM against RIF-R1 MTB strain, followed by INH-R1 MTB strain with IC50 of 3.5 µM and 3.4 µM, respectively. Against FQ-R1 MTB strain, the lead compounds 4f and 5f displayed excellent inhibition at IC50 5.9 µM and 4.9 µM, respectively indicating broad-spectrum of activity. Further, molecular docking, ADME pharmacokinetic and molecular dynamics simulations of the compounds were performed against the DNA gyrase B and obtained encouraging results.

Isatin-Hydrazones with Multiple Receptor Tyrosine Kinases (RTKs) Inhibitory Activity and In-Silico Binding Mechanism

Recently, we have reported a series of isatin hydrazone, two of them, namely, 3-((2,6-dichlorobenzylidene)hydrazono)indolin-2-one (1) and 3-((2-chloro-6-fluorobenzylidene)hydrazono)indolin-2-one (2) having potent cytotoxicity, showing cyclin-dependent kinases (CDK2) inhibitory activity and bearing recommended drug likeness properties. Since both compounds (1 and 2) showed inhibitory activity against CDK2, we assumed it would also have multiple receptor tyrosine kinases (RTKs) inhibitory activity. Considering those points, here, above-mentioned two isatin hydrazone 1 and 2 were synthesized using previously reported method for further investigation of their potency on RTKs (EGFR, VEGFR-2 and FLT-3) inhibitory activity. As expected, Compound 1 exhibited excellent inhibitory activity against epidermal growth factor receptor (EGFR, IC50 = 0.269 µM), vascular epidermal growth factor receptor 2 (VEGFR-2, IC50 = 0.232 µM) and FMS-like tyrosine kinase-3 (FLT-3, IC50 = 1.535 µM) tyrosine kinases. On the other hand, Compound 2 also exhibited excellent inhibitory activity against EGFR (IC50 = 0.369 µM), VEGFR-2 (IC50 = 0.266 µM) and FLT-3 (IC50 = 0.546 µM) tyrosine kinases. A molecular docking study with EGFR, VEGFR-2 and FLT-3 kinase suggested that both compounds act as type I ATP competitive inhibitors against EGFR and VEGFR-2, and type II ATP non-competitive inhibitors against FLT-3.

Novel coumarin-isatin hybrids as potent antileishmanial agents: Synthesis, in silico and in vitro evaluations

Leishmaniasis being one of the six major tropical diseases that affects nearly 0.7–1.3 million people annually, has so far limited and high toxic therapeutic options. Herein, we report the synthesis, in silico, and in vitro evaluations of novel coumarin-incorporated isatin hydrazones (Spf-1 – Spf-10) as highly potent and safe antileishmanial agents. Molecular docking was initially carried out to decipher the binding confirmation of lead molecules towards the active cavity of the target protein (Leishmanolysin gp63) of Leishmania tropica. Among all the docked compounds, only Spf-6, Spf-8, and Spf-10 showed high binding affinities due to a pattern of strong conventional hydrogen bonds and hydrophobic π-interactions. The molecular dynamics simulations showed the stable pattern of such bonding and structure-based confirmation with a time scale of 50 ns towards the top compound (Spf-10) and protein. These analyses affirmed the high stability of the system. Three out of ten compounds evaluated for their antileishmanial activity against Leishmania tropica promastigotes and amastigotes were found to be active at micromolar concentrations (IC50 range 0.1–4.13 μmol/L), and most importantly, they were also found to be highly biocompatible when screened for their toxicity in human erythrocytes.

Role of ZnO chelation for boosting photoresponse performance of isatin hydrazone/p-Si organic/inorganic heterojunctions for energy conversion approach

In this study, the new isatin hydrazone derivative (IL) and its ZnO-complex (ZnOIL) were synthesized to be employed in solar energy conversion applications. The structural characterizations of IL and ZnOIL were carried out by energy-dispersive X-ray spectroscopy, UV–Vis spectroscopy, mass spectrometry, and nuclear magnetic resonance. Au/IL(200 nm)/p-Si and Au/ZnOIL(200 nm)/p-Si heterojunctions were fabricated using the thermal evaporation method. Comparative studies have been made between photoresponse performance of Au/IL/p-Si and Au/ZnOIL/p-Si heterojunctions using impedance spectroscopy analysis under the same environmental conditions. Bode and Nyquist plots of both devices were investigated in dark and under different illuminations (0 – 160 Klux). Furthermore, the dielectric functions and the electric modulus were determined under different illuminations and frequencies. The behavior of electrical conductivity was examined under various illumination conditions. The results showed that the IL ligand and its ZnOIL complex possess an excellent photoresponse and semiconducting properties. The fabricated device based on ZnOIL complex (Au/ZnOIL/p-Si) exhibits better photoresponse performance and electrical characteristics than that one based on IL ligand (Au/IL/p-Si). ZnO chelated IL as a new method to form ZnOIL in photovoltaic devices, promoted their photoelectrical properties ,which enhance their photoresponse performance. Thereby the synthesized ZnOIL could be used as a potential material to improve the performance of solar energy conversion devices.

Improvement of photoresponse in an isatin hydrazone/CdTe hybrid heterostructure device via ZnO chelation for photovoltaic applications

In the present study, a new approach for obtaining a new isatin hydrazone (IL) dye has been carried out. Two types of hybrid inorganic/organic heterojunctions based on CdTe/IL and CdTe/ZnOIL have been fabricated using IL and ZnOIL nano thin films. The impedance spectroscopy technique was used to compare FTO/CdTe/IL/Al and FTO/CdTe/ZnOIL/Al heterojunctions by applying different AC frequencies (42 Hz–5 MHz) and under different light irradiance intensities (0–90 kLux). Besides, the AC electrical properties of the fabricated heterojunctions were examined and compared with each other. The results showed that the fabricated device based on ZnOIL organic interfacial film reveals better electrical characteristics than that based on IL ligand. The enhancement of photoconductive and carrier lifetime in the hybrid system of FTO/CdTe/ZnOIL/Al is correlated with the formation of ZnOIL charge transfer in the ZnO-complex demonstrated by impedance spectroscopy analysis. The obtained result and the comparative study is drawn in the present work supply a new direction for improving the performance of the CdTe solar cells-based IL and ZnOIL interfacial organic layers.

Synthesis, physicochemical and optical characterizations of a new isatin hydrazone derivative and its ZnO-complex for potential energy conversion and storage applications

We synthesized a novel isatin hydrazone derivative 3-(((E)-3-ethoxy-2-hydroxybenzylidene)hydrazineylidene)indolin-2-one (IL) via condensation of isatin hydrazide with 3-ethoxy-salicylaldehyde in methanol. Then ZnO was chelated with the ligand (IL) to produce a novel ZnOIL complex. The characteristics of the IL and ZnOIL compounds were compared using various techniques, including nuclear magnetic resonance, ultraviolet–visible, infrared, and mass spectroscopy, and elemental analyses to confirm their chemical compositions. The optical properties of the IL and ZnOIL thin films were studied based on spectroscopic measurements of their absorbance, transmittance, and reflectance within the range of 300–2500 nm. The optical constants, dielectric parameters, and dispersion energies were determined and interpreted. The electronic inter-band transitions of the IL and ZnOIL films were characterized by indirect allowed transitions. The value of the optical band gap (Eg) was determined as 2.14 eV for the IL film, but chelation of IL with ZnO decreased Eg to 2.02 eV. The surface and volume energy loss functions were lower for ZnOIL compared with IL. The structural and the optical features of ZnOIL may be tuned, and thus it is a promising candidate material for applications in energy conversion and storage devices.

Colorimetric ‘naked eye’ sensor for fluoride ion based on isatin hydrazones via hydrogen bond formation: Design, synthesis and characterization ascertained by Nuclear Magnetic Resonance, Ultraviolet–Visible, Computational and Electrochemical studies

A new colorimetric sensor ‘R-IND’ based on isatin hydrazones have been designed and synthesized by simple Schiff base reaction. The anion sensing properties of R-IND were examined, characterized by common spectroscopic techniques such as Fourier Transform-Infrared (FT-IR), Ultraviolet–Visible (UV–Visible), Proton and Carbon Nuclear Magnetic Resonance (1H &13C NMR), Electrospray Ionization Mass Spectroscopy (ESI-MS) and electrochemical studies. The sensor R-IND bearing ortho hydroxy group and amine group acting as binding sites. The sensor R-IND exhibited sensitive and selective sensing towards F− ion over the other competitive anions like Cl−, I−, Br−, H2PO4−, AcO−, CN–, NO3–, ClO4− and HSO4− in 100% Aetonitrile and 20% aqua Acetonitrile media. The bathochromic shift of 222 nm and 228 nm was observed in UV–Vis spectra with a color change from pale yellow to purple which is due to the complex formation between R-IND and F− ion through hydrogen bond formation. This was further accounted by 1H NMR titration. The Job’s plot reveals 1:2 stoichiometry between the host-guest complex. Binding and association constants were found to be 1.72 × 109 M−1, 2.82 × 109 M−1 and 6.0 × 105 M−1, 2.0 × 106 M−1 in 100% ACN and 20% aqua ACN respectively. The detection limit of sensor R-IND was turned out to be 0.45 and 0.41 ppm for F− ion in organic and aqua organic medium which is lesser than World Health Organization (WHO) permission level (1 ppm). The characteristic potential difference of 1.069 V has been observed for R-IND+F− complex in the electrochemical study. Finally, economically viable paper-based colorimetric test strips of R-IND were developed to detect the F− ions in 100% aqueous solution.

ON/OFF Photostimulation of Isatin Bipyridyl Hydrazones: Photochemical and Spectral Study.

Four novel isatin hydrazones containing bipyridyl fragments were synthesized as potential ON/OFF switches. Hydrazone Z-isomers exhibit high thermal stability. The characteristic photochemical reaction for all studied hydrazones is the Z–E isomerization in CHCl3. After irradiation of hydrazones 1 and 2 in dimethylformamide (DMF), the photoreaction products are tautomers. When using light with the appropriate wavelength, the photo-tautomerization reaction is reversible. In these conditions, studied hydrazones have ON/OFF switch properties. In the case of hydrazones 1 and 2, by alternating heat and light stimulation it is possible to control the isomerization process reversibly. In the presence of fluoride ions, NH hydrogen from the studied hydrazones is cleaved, and the corresponding anions are formed. The resulting anions of Z-isomers are changed to the corresponding E-isomer at room temperature.

Synthesis and pharmacological screening of new isatin-3-[N2-(benzimidazol-1- acetyl)]hydrazone

Twenty new isatin-3-[N2-(benzimidazol-1-acetyl)]hydrazones (IV) were synthesized from ten different isatin-3-[N2–(chloroacetyl)] hydrazones (III) by reacting with benzimidazole and 2-methyl benzimidazole. The intermediates were obtained from isatin hydrazones (II) on condensation with chloroacetyl chloride. These compounds were characterized by IR, 1H NMR and mass spectra. All the compounds were screened for antimicrobial, antioxidant and cytotoxic activity. Some of the new compounds showed promising antibacterial and antifungal activity. KEY WORDS: Antibacterial activity, Antifungal activity, Antioxidant activity, Cytotoxic activity, Benzimidazole, Isatin Bull. Chem. Soc. Ethiop. 2019, 33(2), 321-329. DOI: https://dx.doi.org/10.4314/bcse.v33i2.12

Unexpected formation of polymeric silver(I) complexes of azine-type ligand via self-assembly of Ag-salts with isatin oxamohydrazide.

Isatin oxamohydrazide (L) reacted with the aqueous solution of silver nitrate at room temperature afforded the polymeric silver(I) nitrato complex, [Ag2L′(NO3)2]n, (1) of the azine ligand (L′). Similarly, the reaction of L with silver(I) perchlorate gave the [Ag2L′2(ClO4)2]n, (2) coordination polymer. Careful inspection of the crystals from the nitrato complex preparation showed the presence of another crystalline product which is found to be [Ag(Isatin-3-hydrazone)NO3], (3) suggesting that the reaction between silver(I) nitrate and L proceeds first by the hydrolysis of L to the isatin hydrazone which attacks another molecule of L to afford L′. Testing metal salts such as Ni2+, Co2+, Mn2+, Cu2+ and Cd2+ did not undergo any reaction with L either under the same reaction conditions or with heating under reflux up to 24 h. Treatment of the warm alcoholic solution of L with few drops of 1 : 1 (v/v) hydrochloric acid gave the free ligand (L′) in good yield. The [Ag2L′(NO3)2]n complex forms a two-dimensional infinite coordination polymer, while the [Ag2L′2(ClO4)2]n forms one-dimensional infinite chains with an alternating silver-azine backbone. Quantitative analysis of the intermolecular interactions in their crystals is made using Hirshfeld surface analysis. Density functional theory studies were performed to investigate the coordination bonding in the studied complexes.

Molecular Design, Synthesis, Computational Screening, Antimicrobial Evaluation and Molecular Docking Study of Acetylinic Isatin Hybrids

AbstractAs a part of our program to compose multicomponent hybrid templates with potential pharmaceutical recognition, we have designed a library of acetylinic isatin hydrazones (1 b‐1 p) and acetylinic spiroisatins (1 q‐1 s). All the synthesized motifs were thoroughly characterized and then evaluated for their antimicrobial activities followed by cytotoxic appraisal of the more potent compounds in Hek293 and HeLa human cancer cell lines. Computer aided drug design filtered the compounds considered unsuitable for screening purposes. Acetylinic isatin 1 e was the most potent antibacterial scaffold with IC50 ≈ 1.95 μM against E. coli while 1 n with bis‐isatin assembly was the lead compound against C. albicans with IC50 ≈ 15.67 μM. SAR allowed to have a thorough anticipation of the substituent effect on the observed bioactivities of the compounds. Further, docking studies of the selected scaffolds on admissible bacterial and fungal proteins elicited isatin 1 a to exhibit highest ligand efficiency. Molecular interactions disclosed that 3’N substituted isatin derivatives may be considered ==as efficient candidates to curb bacterial and fungal diseases.