Cobalt(II) porphyrazine as an active component of iodide-selective electrodes

Cobalt(II) porphyrazine is synthesized and studied as an active component of a polyvinyl chloride plasticized membrane ion-selective electrodes (ISEs). It is established that regardless of their structure, ISEs are sensitive to iodide. The introduction to the ISE of an ionic additive, ionic liquid 1,3-dihexadecylimidazolium chloride, significantly improves the electrochemical characteristics: the slope of the electrode function reaches ?(57 ± 1) mV/dec, c_min = 8.3 × 10^–6 M. Solid-state screen-printed electrodes the surfaces of which are modified by a 1: 4 mixture of cobalt(II) porphyrazine and ionic liquid 1,3-dihexadecylimidazolium chloride demonstrate satisfactory electrochemical characteristics: the slope of the electrode function is ?(56 ± 4) mV/dec and c_min = 2.5 × 10^–5 M. The potentiometric selectivity of the ISEs for iodide is studied. It is found that the effect of lipophilic interfering ions is significantly lower for solid state ISEs than for plasticized membrane electrodes.     

A New Highly Selective Neodymium(III) Polyvinylchloride Membrane Electrode Based on 4-Hydroxypyrrolidine-2-Carboxylic Acid as an Active Material

The present paper describes the fabrication of a new polyvinylchloride (PVC) membrane electrode for the determination of Nd(III) ion based on 4-hydroxypyrrolidine-2-carboxylic acid (LHP) as an active material along with sodium tetraphenyl borate (NaTPB) as an anionic additive and acetophenone (AP) as solvent mediator. The optimum composition (%, w/w) of the best performing membrane contained 66 AP, 30 PVC, 2 NaTPB and 3 LHP. The basic analytical parameters of this electrode such as slope characteristics, detection limit, response time, selectivity and pH effect were assessed. The electrode displayed a Nernstian response in terms of slope (20.5 ± 0.4 mV per decade) and response time (~8 ± 1 s) over a wide neodymium ion concentration range of 10^–6 to 10^–2 M with a detection limit of 7.5 × 10^?7 M. The potentiometric response of the electrode was constant in the pH range of 3.2?8.9. According to the selectivity coefficients determined by the matched potential method, the interference of many common alkaline, alkaline earth, transition, heavy metals and specially lanthanide ions in determination of Nd(III) ion was very low. The proposed electrode has been successfully used as an indicator electrode in the potentiometric titration of Nd(III) ion with EDTA and applied for determination of Nd(III) ion in mixtures of different ions.     

Single-Walled Carbon Nanotubes Functionalized with N-(6-aminohexyl) Carboxamide as Ionophore for Sensing Silver Ions

In this work; we constructed a silver ion-selective electrode based on N-(6-aminohexyl) carboxamide functionalized single-walled carbon nanotubes (NAHAFSWCN) as an ionophore. The selectivity constant of a number of cations was measured using silver ion selective electrode. Optimal pH was between 3 and 6 and the upper and lower detection limits of the designed electrode were 1.2 × 10^–2 and 8 × 10^–7 M. The electrode showed a Nernstian response over a silver ion concentration range of 1 × 10^–6 to 1 × 10^–2 M with a slope of 59.1 ± 0.5 mV/decade. The response time of the electrode was less than 18 s and its effective lifetime was 3 months. The isothermal temperature coefficient of the electrode dE°/dT was determined as 0.00011 V/grad. Thermodynamic functions such as ΔS°, ΔH° and ΔG° were obtained by calculating the thermal coefficient of the electrode.     

Transition metal tetrapentafluorophenyl porphyrin catalyzed hydrogen evolution from acetic acid and water

The performance of Cu (1), Co (2) and Zn (3) complexes of meso-tetrakis(pentafluorophenyl)porphyrin in the electrocatalyzed evolution of hydrogen has been investigated. In acetic acid media, hydrogen evolution turnover frequency (TOF) values for complexes 1, 2 and 3 were 22.1, 19.8 and 18.1 h^?1, respectively, at an overpotential of 942 mV versus Ag/AgNO₃. In buffer solution at pH 7.0, the corresponding hydrogen evolution TOF values increased dramatically, to 266, 234, 218 h^?1 at a similar overpotential of 878 mV versus SHE. The Faradaic yields of 1, 2, and 3 for sustained proton reduction in catalytic experiments at a glassy carbon electrode over 72 h were 89.7, 90.4 and 91.0%, respectively, with no observable catalyst decomposition.     

Ionophore Properties of Schiff Base Compounds as Ion Sensing Molecules for Fabricating Cu(II) Ion-Selective Electrodes

Bis(2-hydroxybenzaldehyde)-1,2-diaminoethane (L^I), bis(2-hydroxybenzaldehyde)-1,3-diaminopropane (L^II) and bis(2-hydroxybenzaldehyde)-4,4'-methylendianiline (L^III) were examined as ionophores for fabrication of polyvinylchloride (PVC) membrane Cu(II) ion-selective potentiometric sensors. The optimum composition (%) for the sensors was: 5 L^I, 30 PVC, 6 sodium tetraphenylborate (NaTPB), 59 ortho-nitrophenyloctyl ether (NPOE); 4 L^II, 30 PVC, 5 NaTPB, 61 dibutyl phthalate; 6 L^III, 30 PVC, 5 NaTPB, 59 NPOE. The linear response range of the electrodes was 5 × 10^–4–0.05 (L^I), 5 × 10^–4–0.1 (L^II) and 1 × 10^–6–0.01 M (L^III), and the corresponding detection limits were 4 × 10^–4, 4 × 10^–4 and 2 × 10^–7 M, respectively. The sensors were showed rapid response time (≈10 s). Their responses were independent on pH in the range 2.5–5.0 (L^I), 3.2–4.7 (L^II) and 4.0–5.0 (L^III). The selectivity of the prepared electrodes towards copper ions over some mono-, di- and trivalent metal ions was evaluated. The sensors were used as indicator electrode in potentiometric titration of copper ions in aqueous solutions.     

Polymer matrices with molecular memory as affine adsorbents for the determination of myoglobin as a cardiac marker of acute myocardial infarction by voltammetry

A possibility of myoglobin determination using screen-printed graphite electrodes modified with a poly(o-phenylenediamine)-based molecularly imprinted polymer (MIP) obtained by the electropolymerization of o-phenylenediamine monomer molecules on the surface of a screen-printed graphite electrode in the presence of myoglobin template molecules is considered. It is shown that the conjugation of MIP with multiwall carbon nanotubes (MWCNT) results in an increase in the sensitivity of the MIP-biosensor in the electrochemical determination of myoglobin by the direct registration of the reduction peak of hemoprotein Fe³⁺ by square wave voltammetry on screen-printed graphite electrodes modified with MWCNT/MIP and MIP. Equilibrium dissociation constants K _d for the interaction of myoglobin with MWCNT/MIP- and MIP-electrodes, which equaled (9.8 ± 2.6) × 10^–11 and (2.4 ± 0.5) × 10^–8 M, respectively, are calculated. It is shown that the sensitivity of the electrochemical MWCNT/MIP-biosensor for myoglobin determination (1.5 × 10^–2 A/nmol of myoglobin) is higher than that of the MIP-biosensor (2.0 × 10^–4 A/nmol of myoglobin).     

Homo- and heteronuclear iron complexes {Fe<Subscript>2</Subscript>MO} with salicylic acid: Synthesis,structures, and physicochemical properties

A reaction of iron nitrate with magnesium salicylate and reactions of iron and cobalt chlorides with ammonium salicylate in the presence of water, methanol, DMAA, and DMF gave the trinuclear heterometallic complexes: [hexa-μ-salicylato-μ₃-oxo-0.4-dimethylacetamide-2.6-aquadiiron(III)magnesium(II)] tetra(dimethylacetamide), [Fe₂MgO(SalH)₆(DMAA)_0.4(H₂O)_2.6]·4DMAA (I); [hexa-μ]-salicylato-μ₃-oxo(dimethanol)aquadiiron(III)cobalt(II)] dimethylformamide · 2.5-hydrate, [Fe₂CoO(SalH)₆(CH₃OH)₂(H₂O)] · DMF · 2.5H₂O (II); and [hexa-μ-salicylato-μ₃-oxotriaquatriiron(III)] chloride dimethylacetamide monohydrate, [Fe₃O(SalH)₆(H₂O)₃]Cl · DMAA · H₂O (III). The X-ray study revealed that the molecular structures of complexes I and II are [Fe₂ ^IIIM^II(μ₃-O)(RCOO)₆L₃] · nSolv. The IR and Mössbauer spectra of complexes I–III were examined; their magnetochemical and thermal properties were studied. The parameters of the Mössbauer spectra (δ_Na ⁺ = 0.69 ± 0.03 mm/s, ΔE _Q = 0.76–1.08 mm/s, 300 K) suggest the high-spin state of the Fe³⁺ ions in complexes I–III (S = 5/2). The paramagnetic Fe³⁺ ions are involved in antiferromagnetic exchange interactions with the parameter J = ?44 cm^?1, g = 2.05 (for I). Complexes I–III are thermally unstable.     

Structures and enhanced third-order nonlinear optical performance of four complexes investigated by thin film <Emphasis Type="Italic">Z-</Emphasis>scan technique

Four transition metal complexes have been synthesized via hydrothermal reactions, namely, [Zn(1,3-BIB)(CH₃COO)₂]₂ 1, [Cu₂(1,4-BIB)₃(CO₃)₂](1,4-BIB)·10H₂O 2, {[Mn(H₂O)₂(1,2-BIB)₂]Cl₂}_n 3, and {[Mn(1,2-BIB)(1,4-NDC)]₂}_n 4, where 1,n-BIB = 1,n-bis(imidazol-l-yl-methyl)benzene, n = 2, 3, 4 and 1,4-NDC = naphthalene-1,4-dicarboxylic acid. Complex 1 presents a discrete ring-like structure. Complex 2 shows a ladder-like chain structure, while complex 3 has a joint-like chain structure. Complex 4 features a layer structure constructed from [Mn₂(N₄O₈)] clusters. The third-order nonlinear optical (NLO) properties of these complexes in thin films have been investigated by employing the Z-scan technique. Complexes 1–3 exhibit strong third-order NLO reverse-saturable absorption, while 4 shows third-order NLO saturable absorption and a strong self-defocusing effect. The third-order NLO susceptibilities χ ⁽³⁾ of the four complexes were calculated as 2.74 × 10^?9, 12.24 × 10^?9, 42.78 × 10^?9 and 189.32 × 10^?9 esu, respectively. The electronic structures of the complexes were investigated by density functional theory, and the origins of their NLO properties are discussed.     

The role of copper(II) ions in the oxidation of 5-hydroxy-6-methyluracil in the ground and electronically excited states with molecular oxygen in aqueous solutions

A spectral fluorescence study of photoinduced reactions in aqueous solutions has been carried out in order to examine the mechanisms of the oxidation of 5-hydroxy-6-methyluracil (I) in the ground and electronically excited states by molecular oxygen in the presence of copper(II) chloride. It has been found that 5,5,6-trihydroxy-6-methylpyrimidine-2,4-dione (II) is formed upon the photolysis of I. The spectral parameters (λ_max) and the quantum yields (φ) of fluorescence (FL) of compounds I (φ = 8 × 10^–4; λ_max = 362 nm) and II (φ = 17 × 10^–4; λ_max = 306, 330 nm) have been determined. A reaction scheme was proposed, according to which the photooxidation of I occurs through the steps of the generation of the radical cation I ^?+ and the superoxide anion О ₂ ^?- with the subsequent formation of 5,5,6-trihydroxy-6-methylpyrimidine-2,4-dione. The catalytic and inhibitory effects of Cu(II) ions on the oxidation of 5-hydroxy-6-methyluracil in the ground and electronically excited states, respectively, by the oxygen radical anion О ₂ ^?- have been revealed.     

Electrocatalytic performance of cobalt microparticles film-modified platinum disk electrode for amperometric detection of ascorbic acid

Deposited cobalt microparticales (Co-MPs) film onto the platinum disk electrode has been successfully used as a new amperometric sensor for the determination of ascorbic acid (AA). AA is detected by surface catalyzed oxidation involving cobalt(III) oxyhydroxides in alkaline solution. The Co-MPs/Pt electrode exhibits a high electrocatalytic activity toward the AA oxidation. The diffusion coefficient of AA (6.09 × 10⁵ cm²/s) and the catalytic rate constant (k _cat = 6.27 × 10³ M^–1s^–1) have been determined using electrochemical approaches. The amperometric response of the modified electrode is linear against the AA concentration in the range (0.01?0.48 mM). The sensor displays the best activity with a high response signal, a good sensitivity of 74.3 μA/mM, a low detection limit of 2.5 μM (signal/noise = 3) and a fast response time (<3 s). Moreover, the reproducibility, selectivity and applicability of this biosensor are satisfactorily evaluated.     

Thermal properties of dimethylgold(III) 8-hydroxyquinolinate and 8-mercaptoquinolinate

Dimethylgold(III) complexes with 8-hydroxyquinoline Me₂Au(Ox) (I) and 8-mercaptoquinoline Me₂Au(Tox) (II) were synthesized and studied. Complex II obtained for the first time was identified from the elemental analysis, IR, ¹H NMR, and mass spectrometry data. The thermal properties of complexes I, II in condensed state were investigated by thermography. The temperature dependences of the saturated vapor pressure over crystals were measured by the Knudsen effusion method with mass spectrometric recording of the gas phase composition and the thermodynamic characteristics of the sublimation process were determined: for I, log P[Torr] = (14.6 ± 0.3) ? (6.34 ± 0.10) × 10³/(T, K), Δ H _subl ^o = 121.2 ± 1.9 kJ^?1, Δ S _subl ^o = 224.1 ± 4.6 J mol^?1 K^?1 (the temperature interval under study 80–115°C); for II, log P [Torr] = (13.3 ± 0.2) ? (6.30 ± 0.09) × 10³/(T, K), Δ H _subl ^o = 120.5 ± 1.7 kJmol^?1, ΔS _subl ^o = 199.3 ± 3.0 J mol^?1 K^?1 (86–145°C).     

Synthesis,characterization, and ethylene oligomerization of three novel dendritic nickel catalysts

Three dendritic nickel complexes C1–C3 were synthesized from three poly(amido amine) dendrimers, salicylic aldehyde and nickel chloride hexahydrate via Schiff base condensation reaction and coordination reaction. The structures of the dendritic ligands and nickel complexes were characterized by FT-IR, UV, ¹H NMR, ESI–MS, and elemental analysis. When activated with aluminum co-catalysts, three complexes C1–C3 were able to catalyze ethylene oligomerization. The catalytic activities and the product distribution of complexes C1–C3 were depended on the reaction parameter, co-catalyst, solvent, and the structure of the pre-catalyst. When using ethyl aluminum sesquichloride (EASC) as co-catalyst in toluene, the catalytic activity of complex C3 containing the longest bridging methylene groups reached the highest value of 1.63 × 10⁶ g·(mol Ni·h)^?1 with 69.15% C₁₁ in the product at 30 min, 25 °C, 0.5 MPa, and Al/Ni ratio of 900.     

Synthesis and biological evaluation of novel triazole substituted pyrazolyl-methylenehydrazinyl-5-arylidene thiazolidinone derivatives as antibacterial and cytotoxic agents

Novel triazole substituted pyrazolyl-methylenehydrazinyl-5-arylidene thiazolidinone derivatives 6a–n and 7a–l were synthesized and characterized by Fourier transform infrared, ¹H and ¹³C nuclear magnetic resonance, mass spectrometry and elemental (CHN) analysis. The in vitro antibacterial (6a–n and 7a–l) and cytotoxic (6a–n) activities were evaluated for these compounds. The results revealed that the compounds 6b, 6i, 6k, 7b, 7h displayed good antibacterial activity. The compounds 6c (IC₅₀ = 5.4 μM), 6l (IC₅₀ = 6.3 μM) and 6f (IC₅₀ = 9.85 μM) were effective for inhibition of human breast cancer cell line MCF-7. Similarly, the compounds 6b (IC₅₀ = 8.7 μM) and 6c (IC₅₀ = 9.06 μM) were shown to have effective inhibition on human cervical cancer cell line Hela.     

Synthesis and dynamics studies of barbituric acid derivatives as urease inhibitors

Background

Discovery of potent inhibitors of urease (jack bean) enzyme is the first step in the development of drugs against diseases caused by ureolytic enzyme.

Results

Thirty-two derivatives of barbituric acid as zwitterionic adducts of diethyl ammonium salts were synthesized. All synthesized compounds (4a–z and 5a–s) were screened for their in vitro inhibition potential against urease enzyme (jack bean urease). The compounds 4i (IC₅₀ = 17.6 ± 0.23 µM) and 5l (IC₅₀ = 17.2 ± 0.44 µM) were found to be the most active members of the series, and showed several fold more urease inhibition activity than the standard compound thiourea (IC₅₀ = 21.2 ± 1.3 µM). Whereas, compounds 4a–b, 4d–e, 4g–h, 4j–4r, 4x, 4z, 5b, 5e, 5k, 5n–5q having IC₅₀ values in the range of 22.7 ± 0.20 µM–43.8 ± 0.33 µM, were also found as potent urease inhibitors. Furthermore, Molecular Dynamics simulation and molecular docking studies were carried out to analyze the binding mode of barbituric acid derivatives using MOE. During MD simulation enol form is found to be more stable over its keto form due to their coordination with catalytic Nickel ion of Urease. Additionally, structural–activity relationship using automated docking method was applied where the compounds with high biological activity are deeply buried within the binding pocket of urease. As multiple hydrophilic crucial interactions with Ala169, KCX219, Asp362 and Ala366 stabilize the compound within the binding site, thus contributing greater activity.

Conclusions

This research study is useful for the discovery of economically, efficient viable new drug against infectious diseases.

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Graphical abstract: STD. Thiourea (IC₅₀ = 21.2 ± 1.3 µM)

     

Mesitylenesulfonic acid dihydrate: structure and proton conductivity

The molecular and crystal structure of single-crystalline mesitylenesulfonic acid dihydrate (1) was determined by X-ray diffraction and IR spectroscopy. According to X-ray diffraction data, water molecules in the crystal structure form H₅O₂ ⁺ cations stabilized by an intracationic hydrogen bond with a length of 2.45(1) Å. The formation of the asymmetric H₅O₂ ⁺ cation was confirmed by IR spectroscopy. The crystallographic nonequivalence of the water molecules results in a shift of the bridging proton from the midpoint of the strong hydrogen bond in the cation toward one of the water molecules. The proton conductivity of compound 1 was measured by impedance spectroscopy. Dihydrate 1 is completely dehydrated upon prolonged storage in a dry argon glove box and undergoes the transition to the dielectric state. Compound 1 is stable in the humidity range of 32–66 rel.%. The conductivity of dihydrate 1 is (2.4±0.3) · 10^?5 Ohm^?1 cm^?1 at 298 K, E _a = 0.21±0.01 eV.     

Synthesis,Crystal Structure,Luminescence Sensing,and Photocatalytic Properties of a 2D Cobalt(II) Coordination Polymer Containing Bis(benzimidazole) Moieties

A new cobalt(II) coordination polymer, namely [Co(L)(Ndc)] _n (I), where L = 1,5-bis(5,6- dimethylbenzimidazole)pentane, H₂Ndc = 2,6-naphthalenedicarboxylic acid, was synthesized and characterized by elemental analysis, IR spectra, powder X-ray diffraction and single-crystal X-ray diffraction (CIF file CCDC no. 1548044). Complex I displays a 2D (4,4) layer which further extended into a 3D supramolecular framework via weak C–H···O hydrogen bondings. The luminescence explorations demonstrated that I exhibits highly selective and sensitive sensing for Cr₂O ₇ ^2? with high quenching efficiency K_sv value of 9.87 × 10³ L mol^?1 and low detection limit (0.24 μM (S/N = 3)). Meanwhile I also exhibits highly selective and sensitive sensing for Fe³⁺ with quenching efficiency K_sv = 3.6 × 10⁴ L mol^–1 and low detection limit (0.32 μM (S/N = 3)). Complex I exhibits higher photocatalytic activities for the degradation of methylene blue under UV irradiation. Additionally, the thermal behavior and electrochemical properties of the compound are also presented.     

Binding of carboxylate and trimethylammonium salts to octa-acid and TEMOA deep-cavity cavitands

In participation of the fifth statistical assessment of modeling of proteins and ligands (SAMPL5), the strength of association of six guests (3–8) to two hosts (1 and 2) were measured by ¹H NMR and ITC. Each host possessed a unique and well-defined binding pocket, whilst the wide array of amphiphilic guests possessed binding moieties that included: a terminal alkyne, nitro-arene, alkyl halide and cyano-arene groups. Solubilizing head groups for the guests included both positively charged trimethylammonium and negatively charged carboxylate functionality. Measured association constants (K _a ) covered five orders of magnitude, ranging from 56 M^?1 for guest 6 binding with host 2 up to 7.43 × 10⁶ M^?1 for guest 6 binding to host 1.     

Structure and Chemical Bonding of the B<Subscript>3</Subscript>S<Stack><Subscript>n</Subscript><Superscript>0/−</Superscript></Stack> (<Emphasis Type="Italic">n</Emphasis> = 2–4) Boron Sulfide Clusters: A Density Functional Theory Investigation

A density functional theory investigation on the structural and bonding properties of B₃S _n ^?/0 (n = 2–4) series has been performed. Based on B3LYP and CCSD(T) calculations, we present the linear D _∞h B₃S₂ ^? (1, ³Σ_g) and D _∞h B₃S₂ (2, ²Π_u), the Y-shaped C _2v B₃S₃ ^? (3, ¹A₁) and C _2v B₃S₃ (4, ²B₂), and perfectly planar structures C _2v B₃S₄ ^? (5, ¹A₁) and C _2v B₃S₄ (6, ²B₂) that contain rhombic B₂S₂ rings. The 1–6 ground-state structures are planar with linear “B–B–B” core, in which the first and the second S atoms prefer to bond terminally to the terminal B, and the third S atom bonds to the center B, however, when the third S atom is added with the fourth, the atoms tend to be in the bridging positions of two adjacent B atoms. The growth pattern of B₃S _n ^?/0 (n = 2–4) clusters helps to understand the structural properties of the other small boron sulfide clusters. Bonding analyses reveal that a dual or single three-center one-electron (3c–1e) π hypervalent bonds located over the “B–B–B” core of D _∞h B₃S₂ ^? (1) and B₃S₂ (2), respectively. While C _2v B₃S₄ ^? (5) and B₃S₄ (6) with rhombic B₂S₂ rings as the center with –BS and –S units all possess 4c–4e bonds (o-bonds) in the rhombic B₂S₂ rings.     

Supramolecular Heteroleptic Copper(II) Carboxylates: Synthesis,Spectral Characterization,Crystal Structures,and Enzyme Inhibition Assay

Two new complexes of substituted phenyl acetic acids with CuSO₄ · 5H₂O and 2,2′-bipyridine (Bipy) with formula [CuL(Bipy)₂]L · nH₂O, where L = 2-ClC₆H₄CH₂COO^– (I), 2-CH₃-3-NO₂C₆H₃CH₂COO^– (II) and n = 3 (I); 4 (II), have been synthesized. These complexes have been characterized by elemental analysis, FT-IR and X-ray crystal diffraction (CIF file CCDC nos. 1487707 (I), 1487708 (II)). Both complexes are mononuclear and crystallize in the triclinic space group P1?. In both complexes two molecules of Bipy bind equatorially with metal atom and one molecule of substituted phenyl acetic acid binds at axial position giving rise to a distorted five coordinated geometry around copper atom, while the second oxygen atom of carboxylate ligand appears to occupy the sixth position resulting in highly distorted six coordination environments around metal center in both complexes. However, another molecule of substituted phenyl acetic acid along with water molecules lies as co-crystal within the crystal lattice. Two bipyridine molecules in both complexes are lying in different planes and are oriented at dihedral angle of 63.89(8)° and 74.99(11)° in complexes I and II, respectively. Extensive hydrogen bonding because of water molecules present in crystal lattice plays a vital role in the formation of the 3D structure. Additionally, other weak interactions such as π–π interactions markedly influence the supramolecular structure. An investigation of DNA binding ability of both complexes using UV-visible spectroscopy and anti-diabetic capacity is also presented. Results revealed that synthesized complexes bind with SSDNA through intercalation as well as groove binding mode with K_b values of 2.45 × 10⁴ and 7.72 × 10³ M^–1 for complex I and II, respectively. Complex II strongly inhibits in-vitro α-glucosidase with IC₅₀ value of 30.4 μM, while complex I moderately inhibits in-vitro α-amylase with IC₅₀ value of 69.9 μM. Acarbose was employed as standard in both assays.     

Directed assembly of cobalt(II) 1-H-indazole-3-carboxylic acid coordination networks by bipyridine and its derivatives: structural versatility,electrochemical properties,and antifungal activity

This paper describes the hydrothermal synthesis, full characterization, and architectural diversity of three intriguingly bioactive cobalt–organic frameworks, namely, 3D [Co(HL ^? )₂(BPY)] _n ·4nH₂O (1), 2D [Co(HL ^? )₂(BPE)] _n (2), and 2D [Co(HL ^? )₂(DPP)] _n (3) coordination polymers, synthesized through a mixed ligand strategy using H ₂ L (1-H-indazole-3-carboxylic acid) as a main structural block and the flexible bipyridine and its derivatives (BPY = 4,4′-bipydine, BPE = 1,2-bis(4-pyridyl)ethane, DPP = 1,3-bis(4-pyridyl)propane) as auxiliary ligand sources. Complexes 1–3 were isolated as air stable and slightly soluble crystalline solids and characterized using elemental analysis, FT-IR, electrochemical technique, thermogravimetric analysis, powder X-ray diffractometer, and single-crystal X-ray crystallography. The bipyridine derivatives played key roles in defining the structural space group and dimensionality feature of the obtained networks. The abundant H-bonding and π–π stacking interactions in complexes 1–3 gave rise to their intricate metal–organic structures of 3D (1), 2D (2), and 2D (3). In addition, the solutions of complexes 1–3 showed profound antifungal activities against the selected strain of Colletotrichum musae compared with the controlled group using benomyl as a traditional agrochemical fungicide.