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A Schiff base bearing two methyl substituents, namely, 6,6'-((1

Hydroxamic acids [R(CO)N(OH)R'] are flexible compounds for organic and inorganic analyses due to their frailer structures compared to the carboxylic acid. The syntheses and characterization of benzohydroxamic acid (BHA), its CH3-, OCH3-, Cl- para-substituted derivatives and their Cr(III) complexes are reported herein. The metal complexes were synthesized by reacting the hydroxamic acids with chromium(III) chloride hexahydrate in 2:1 molar ratio. The compounds were characterized via melting point, elemental analysis, FTIR, 1H and 13C NMR, TGA, mass spectrometry, molar conductance and UV-Visible. Data analysis suggests that each complex has the Cr(III) center coordinated to the carbonyl and hydroxy oxygen atoms of the hydroxamic acids in bidentate O,O manner and two water molecules to form octahedral geometry. Non-electrolytic behavior of the complexes was shown through their low molar conductivity. Cytotoxicity study against HCT116 and alpha-glucosidase inhibition test revealed that all complexes have higher activity than their parent ligands. Molecular docking study shows that the docking of active complexes is thermodynamically favorable and the inhibition efficiency may depend on the types and the numbers of molecular interactions established in the corresponding stable conformers.

Two tetradentate phenolic Schiff base ligands namely 2,2'-((1 E ,1' E )-(1,2-phenylenebis(azanyl-ylidene))bis(methanylylidene))diphenol, L1H , 2,2'-((1 E ,1' E )-(1,2-phenylenebis(azanylylidene))bis-(methanylylidene))bis(4-fluorophenol), L1F and their new nickel(II) complexes were successfully synthesized, characterized and evaluated for their in vitro anticancer activities against human colon cancer cell lines, HCT116. The compounds were characterized using FT-IR, 1 H and 13 C NMR, UV-Visible, elemental analysis and melting point. The anticancer results revealed that the parent ligands were more active than their corresponding complexes with L1F being the most potent anticancer compound with IC 50 of 2.8 mg/ml.

A Schiff base ligand, 6,6′-dimethoxy-2,2′-[o-phenylenebis(nitrilomethylidyne)]diphenolato (LA), and its mononuclear and dinuclear Ni(II) and Co(II) complexes were synthesized. Structural elucidation was carried out via elemental analysis, molar conductivity, IR, NMR, UV–Vis spectroscopy, TGA and magnetic susceptibility. Single crystal X-ray diffraction of the Ni(LA) complex revealed a square planar geometry of the Ni(II) centre, with the ligand acting as a tetradentate ONNO chelate. Upon coordination to the metal centers, the ν(C N) and ν(C O) peaks shifted to lower frequencies, with appearance of new peaks assignable to ν(M N) and ν(M O) in the ranges 535–560 and 421–460 cm−1, respectively. Ni(LA) and Ni2(LA) complexes are diamagnetic, whereas the Co(LA) and Co2(LA) complexes are paramagnetic with 3 unpaired electrons each. All the complexes displayed low molar conductivities in acetonitrile indicating non-electrolytic behavior. Anticancer screening against human colorectal cancer HCT116 cell lines revealed that both dinuclear complexes were more active than their mononuclear counterparts. Ni2(LA) showed the highest potency with an IC50 value of 0.81 μM.

This paper reports the synthesis, characterization, anticancer screening and quantum chemical calculation of a tetradentate Schiff base 2,2'-((1E,1'E)-((2,2-dimethylpropane-1,3-diyl)bis- (azanylylidene))bis(methanylylidene))bis(4-fluorophenol) (L2F) and its Pd (II) complex (PdL2F). The compounds were characterized via UV-Visible, NMR, IR spectroscopy and single crystal x-ray diffraction. Density Functional Theory (DFT) and time-dependent DFT calculations in gas and solvent phases were carried out using B3LYP, B3P86, CAM-B3LYP and PBE0 hybrid functionals combined with LanL2DZ basis set. Complexation of L2F to form PdL2F was observed to cause a bathochromic shift of the maximum absorption bands of n-π* from 327 to 410 nm; an upfield shift for δ (HC = N) from 8.30 to 7.96 ppm and a decreased wavenumber for ν(C = N) from 1637 to 1616 cm-1. Overall, the UV-Vis, NMR and IR spectral data are relatively well reproduced through DFT and TD-DFT methods. L2F and PdL2F showed IC50 of 90.00 and 4.10 μg/mL, respectively, against human colorectal carcinoma (HCT116) cell lines, signifying increased anticancer activity upon complexation with Pd (II).

A tetradentate ONNO Schiff base bearing two chloro substituents, namely 6,6′-((1E,1′E)-(cyclohexane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(2-chlorophenol) (AD2C), was obtained through condensation of 3-chlorosalicyladehyde with 1,2-cyclohexanediamine. Structure elucidation was performed through physicochemical and spectroscopic analyses viz. melting point, elemental analysis, FTIR, 1H and 13C NMR, UV-Visible and single crystal X-ray diffraction. The ν(C=N) was observed at 1626 cm−1 while the azomethine proton and carbon chemical shifts appeared at 8.27 ppm and 157.56 ppm, respectively. The n‒π*(C=N) absorption band was observed at 324 nm. The crystal structure was stabilized by intramolecular hydrogen bond O˗H···N and intermolecular hydrogen bonds C˗H···O, C˗H···Cl, C˗H···π as well as π···π interactions. The existence of intermolecular interactions was confirmed through Hirshfeld analysis, showing high contribution of H⋯H contact. The B3LYP method was used to calculate the optimized structure of the molecule through density functional theory (DFT) using the 6–311++G(d, p) basis set and was found to be consistent with the X-ray diffraction value. The frontier molecular orbitals and molecular electrostatic potential of the compound investigated through DFT calculations revealed a significantly large energy gap of 4.615 eV and nucleophilic regions located at the hydroxyl groups. The compound showed no antibacterial activity against five bacterial strains namely Bacillus subtilis (ATCC 6633), Proteus vulgaris (ATCC 6380), Pseudomonas aeruginosa, Staphylococcus aureus subsp. aureus Rosenbach (ATCC 6538) and Streptococcus mutans Clarke (ATCC 700,610).

The corrosion efficiency on mild steel in 1 M HCl of three imines obtained from the condensation of tribulin with aniline derivatives, namely 3-(phenylimino) indolin-2-one (TANH), 3-(4-hydroxyphenylimino) indolin-2-one (TANO) and 3-(4-chlorophenylimino) indolin-2-one (TANC) are investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique. TANO exhibited the highest corrosion inhibition efficiency followed by TANC and TANH at optimum concentration of 1.0 mM. Langmuir's adsorption isotherm and X-ray photoelectron spectroscopy (XPS) showed that the adsorption mechanism is a prominent chemisorption phenomenon than physisorption. Based on XPS analysis, the highest inhibition efficiency of TANO was contributed by C O and C N molecules presented in the compound. The active binding sites of TANH, TANO, and TANC on the mild steel surface were determined by calculating Mulliken atomic charges and analysis of the electrostatic potential surface (ESP) at the B3LYP/6-311+G(d,p) level of theory. The correlation of imines inhibition efficiencies with its electronic parameters was investigated and the result showed that the corrosion inhibition efficiency of imines was governed mainly by the frontier orbital energy gap, the chemical softness, and chemical hardness properties.

The development of selective and sensitive chemical sensors to overcome fluoride ions is needed, especially for applications in chemical and biological processes. One of the chemical compounds that can act as sensors is the Schiff base compound group. This study aims to synthesis a Schiff base based on salicylaldehyde and as a fluoride ion sensor. The one-pot synthesis approach was carried out in room terms by mixing salicylaldehyde with hydrazine hydrate or phenylenediamine with a molar ratio of 2: 1 in ethanol solvent under stirring for 24 hours. The bright yellow crystal was obtained with a yield of 80% for salicylaldazine (SB). The compounds in the dimethyl sulfoxide (DMSO) solvent tend to be colorless, but in the presence of F-ions, the solution turns orange. The results indicate an interaction between SB1 with F-ions in solution.

A new Schiff base derived from cyclohexanediamine and 3-methylsalicylaldehyde was obtained. The Schiff base, 6,6′-((1E,1′E)-(cyclohexane-1,2-diylbis(azanylylidene))bis(methanylylidene))bis(2-methylphenol), (AD2Me) was characterized through elemental analysis, infrared, UV-Vis, 1H and 13C nuclear magnetic resonance (NMR) spectroscopy. The structure of the grown crystal was elucidated by using single crystal X-ray diffraction technique. The compound crystallized in the triclinic system, P-1 space group. The cell length and volume for AD2Me are a = 10.4582(11) A, b =10.8141(9) A, c =18.7472(14) A, α = 90.629(7)°, β = 92.444(7)°, γ = 109.561(9)° and V =1995.3(3) A3, respectively. The crystal structure is stabilized by intramolecular hydrogen bond O˗H•••N and intermolecular hydrogen bonds C˗H•••O, C˗H•••π and π•••π. The B3LYP method was used to calculate the optimized structure of the molecule through density functional theory (DFT) using the 6-311G++(d, p) basis set and the results of the conformation analysis was in good agreement with the crystal structure determined by x-ray single crystal diffraction. Additionally, the molecular electrostatic potential, frontier molecular orbitals and chemical reactivity descriptors of AD2Me were further investigated using DFT, revealing the electronic properties of the compound. A Hirshfeld surface analysis was performed to analyze intermolecular interactions in the crystal structure. The compound showed no significant activity against Staphylococcus aureus subsp. aureus Rosenbach (ATCC 6538) and Streptococcus mutans Clarke (ATCC 700610).

A set of three novel dinuclear Ir(III) azomethine complexes was effectively synthesized from Schiff bases namely N,N-bis-(3,4-dihydroxybenzaldehyde)-4,4-diaminodiphenylsulphide (HL1), N,N-bis-(2-hydroxy-5-nitrobenzaldehyde)-4,4-diaminodiphenylsulphide (HL2) and N,N-bis-(2-hydroxy-5-chlorobenzaldehyde)-4,4-diaminodiphenylsulphide (HL3). Structural elucidation was carried out through (CHNS) elemental analysis, FT-IR, NMR, energy dispersive X-ray diffraction (EDX), powder X-ray diffraction (PXRD), UV–Visible and photoluminescence spectroscopy. The FTIR and NMR spectra showed that the ligands contain dioxygen-dinitrogen donor atom system, forming dinuclear complexes IrHL1, IrHL2 and IrHL3 upon coordination with Ir(III) ion. X-ray analysis of a single crystal HL2 confirmed the [NNOO] donor system and demonstrated a bending geometry with the torsion angle of 50.98° for C10–C11–S1–C14 linkage as the result of a significant twist at the central sulphur. The low molar conductivity values revealed the absence of electrolytic anions and cations in the complexes. The powder X-ray diffraction studies indicated the presence of crystalline phase in all the Ir(III) complexes. Photophysical characteristics of the compounds were thoroughly investigated in solid as well as liquid states at ambient conditions. The solid complexes manifested two strong emissions in the visible and near infra-red (NIR) regions. Primarily, at the visible region of 610–615 nm, the emission peak is assigned to ligand centered photoluminescence. The secondary emission peak was detected in the NIR region at 1119–1177 nm, ascribed to the triplet excited state emission of the iridium center. All the synthesized complexes were subjected to thermogravimetric analysis revealing thermal stability exceeding 230 °C before undergoing decomposition. Remarkable solid state photoluminescence activities of IrHL3 and IrHL2, in that order, was exhibited through the Stoke's Shift (Δλ) values of 285 and 289 nm, respectively, consequently merit the complexes as promising keystone for luminescent materials in solid state. The bactericidal activity of the test compounds was investigated on three Gram-positive and three Gram-negative bacteria, unveiling mild to moderate antibacterial activity. The IrHL2 complex with p-nitro substituent showed the highest activity against Streptococcus mutant, Staphylococcus aureus and Pseudomonas aeruginosa, succeeded by IrHL3 complex with p-chloro substituent for Streptococcus mutant.

Hydroxamic acids [R(CO)N(OH)R'] are flexible compounds for organic and inorganic analyses due to their frailer structures compared to the carboxylic acid. The syntheses and characterization of benzohydroxamic acid (BHA), its CH

A series of binuclear azomethine-Zn(II) complexes was successfully synthesized from 4,4-diaminodiphenylsulphide derived Schiff bases, N,N-bis-(3,4-dihydroxybenzaldehyde)-4,4-diaminodiphenylsulphide (L1), N,N-bis-(5-nitrosalicylidene)-4,4-diaminodiphenylsulphide (L2), N,N-bis-(5-chlorosalicylidene)-4,4-diaminodiphenylsulphide (L3). The compounds were characterized through single crystal X-ray diffraction analysis, FT-IR, 1H NMR,13C NMR, energy dispersive X-ray diffraction (EDX), UV–Visible and photoluminescence spectroscopy. Single crystal X-ray diffraction analysis manifested that in the binuclear ZnL3 complex, two zinc ions bridge two Schiff bases with each metal centre adopting a distorted tetrahedral geometry, through coordination with two phenolate oxygen atoms and two azomethine nitrogen atoms. Each L3 ligand bonds two Zn(II) centres on different sides of the metals where the ligand flipped over to the opposite side around the S atom creating a twist. Photophysical properties of the synthesized compounds were explored in solid and solution states at room temperature. In solid state, the complexes revealed emissive properties in the visible and near infra-red (NIR) regions, with large Stoke's shift (Δλ) of 260–385 nm with respect to absorption, exhibiting emission in visible region (585 nm) both for ZnL2 and ZnL3 and dual emissive peaks in the NIR region (710 nm, 1199 nm) for ZnL1. Whereas, emissions in solution state (DMF) with lower intensity occurred at 465–545 nm. All complexes were subjected to thermogravimetric analysis with ZnL2 showing the highest thermal stability of up to 342 °C before undergoing decomposition. The good solid state emission properties illustrated that the complexes featured their potential as promising cost effective solid state photoactive materials.

Hydroxamic acids (RCONHOH) are versatile compounds that constitute a significant biological importance. The syntheses, physico-chemical and characterization of benzohydroxamic acid (BHA) and its metal complexes (VO(IV), Cr(III) and Ni(II)) are reported herein. The metal complexes were synthesized via condensation reaction of BHA and metal salts in 2:1 molar ratio using ethanol as reaction medium. The compounds were characterized by elemental analysis, spectral (infrared, UV-Vis, 1 H and 13 C NMR,), TGA, magnetic susceptibility as well as molar conductance. The spectral study analysis reveals that all complexes coordinated to the metal via oxygen atoms ( O,O ) in bidentate manner to form octahedral for [Cr(BHA 2 ).2H 2 O]H 2 O, tetrahedral for [Ni(BHA) 2 ] and square pyramidal geometry for [VO(BHA) 2 ]. The molar conductance values suggested that all complexes were non-electrolytes. A cytotoxicity study against HCT116 displayed that VO(IV) has better IC 50 values than the parent ligand, BHA but not considered as potent anticancer agents.

Coupling reaction between aryl halide and terminal alkyne in Sonogashira coupling reaction is important due to its extensive application in the resynthesis of natural products, production of drugs, dyes, and polymers. Efforts to increase rate of reaction has involved exploration of new catalysts. The current catalysts such as phosphine-based complexes are costly, air-sensitive and environmentally harmful. Nickel(II) Schiff base complexes were synthesized by reacting aromatic Schiff base ligands 2,2'-((1 E ,1' E )-(1,2-phenylenebis(azanylylidene))bis(metha-nylylidene))diphenol (L1H), 2,2'-((1 E ,1' E )-(1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(4-fluorophenol) (L1F), and 2,2'-((1 E ,1' E )-(1,2-phenylenebis(azanylylidene))bis-(methanylylidene))bis(4-methylphenol) (L1M) with nickel(II) acetate tetrahydrate to form NiL1H, NiL1F and NiL1M. The chemical structures were elucidated through physicochemical and spectral techniques namely elemental analysis, melting point, FTIR, 1 H and 13 C NMR, magnetic susceptibility and molar conductivity. All nickel(II) complexes were tested as catalysts in homogenous Sonogashira reaction between iodobenzene and phenylacetylene in DMSO for 12 hours at 140 o C. NiLF, a new nickel(II) complex, converted the highest percentage of iodobenzene (91%) while NiLH and NiLC converted 78% and 83% of iodobenzene, respectively.

Corrosion is inherent for mild steel and it can be retarded through many approaches including electrodeposition of inert inhibitors in the form of organic molecules. Salicylideneaniline (L1) and 4-hydroxybenzalaniline (L2) were electrodeposited on mild steel using cyclic voltammetry (CV) using 0.1 M inhibitor concentration in 0.3 M NaOH. The scanning potential range for coating via CV was set from 0 - 2 V and back to 0 V for five cycles. A yellow film was observed covering the surface of the mild steel. The corrosion behavior of coated and uncoated mild steel was studied using Linear Polarization Resistance (LPR) in 0.5 M NaCl. Both coated mild steel specimens showed better corrosion resistance than the uncoated, with L1 providing a better inhibition protection with the inhibition efficiency of 80.51 %.

This paper reports the synthesis, characterisation and DFT analysis of an N,O bidentate Schiff base, (( E )-(4-methoxybenzylimino)methyl)phenol, (L1c) and its Ni(II) and Pd(II) complexes. The structures were elucidated via elemental analysis, UV–Visible, NMR, IR and single crystal X-ray diffraction. Complexation of L1c with Ni(II) and Pd(II) was observed to induce different degrees of bathochromic effect on n → π ∗ and π → π ∗ electronic transitions. A comparison of the experimental data of UV–Visible, NMR, IR and X-ray with those calculated using DFT and TD-DFT methods where five hybrid functionals were tested in gas, IEF-PCM and SS-PCM models was also carried out. The results show that the reproduction of maximum absorption bands n → π ∗ and π → π ∗ is strongly related to the tested hybrid functionals and solvatochromic effects. Relatively good concordance was obtained between experimental and calculated NMR chemical shifts, IR and X-ray parameters. A bioactivity evaluation against HCT116 and Escherichia coli displayed that the parent ligand L1c is a more superior anticancer and antibacterial agent than the positive controls of 5FU and gentamicin respectively. However, both complexes showed poor activity as anticancer agent and no activity observed against tested bacteria.

Non-aqueous gel polymer electrolytes (GPEs) consisting of 30% poly(methyl methacrylate)-grafted natural rubber (MG30), lithium triflate (LiTf), and ethylene carbonate (EC) dissolved in tetrahydrofuran are examined as electrolytes for lithium polymer batteries. The AC impedance technique is employed at room and elevated temperatures in the frequency range between 0.1 kHz and 1.0 MHz to optimize the conductivity of MG30–LiTf samples. The membrane containing 35 wt.% of LiTf is found to exhibit the highest ionic conductivity. The introduction of EC resulted in increased ionic conductivity of up to 8.95 × 10−3 S cm−1 at room temperature for the composition MG30(15):LiTf(9):EC(76). The temperature dependence conductivity for all systems studied is of the Vogel–Tamman–Fulcher type. Attenuated total reflectance-Fourier transformed infrared spectroscopic analysis suggested that EC penetrated between the polymer chains without perturbing the complexation that occurred between the polymer and lithium salt. The Li/Li+ interface stability is established to withstand voltages greater than 4.2 V. A lithium polymer half-cell is successfully fabricated using MG30-based GPE and the cell with configuration of Li/MG30:LiTf:EC/LiCoO2 is found to show good cycling efficiency at room temperature.

Two ligands and four complexes are successfully synthesized by reacting 1,8-diaminonapthelene with aldehyde/ketone derivatives in ratio amine:aldehyde/ketone (1:2) for ligands formation and 1:1 ratio (ligand:metals) for complexes formation. The compounds were characterized through CHNS elemental analysis, IR spectroscopy, 1H NMR spectroscopy, melting point determination, and magnetic susceptibility determination. The neurotoxicity screening of compounds was screened using neuroblastoma SH-SY5Y cell lines and it was indicate the cells were non-toxic either for ligands and complexes after 24 hours exposure.

The syntheses, physico-chemical and spectroscopic characterization of ovan-type Schiff-base ligands (L1, L2) and their novel mononuclear Pd(II) complexes (PdL1, PdL2) are reported herein. Elemental analysis, FT-IR,1H NMR as well as magnetic susceptibility measurements characterised the compounds. The catalytic potential of the Pd(II) complexes for Heck coupling reaction were investigated and monitored using GC. It was observed that both Pd(II) complexes displayed properties of good catalysts for the reaction, indicated by 100% conversion of the starting materials to the subtituted alkene product after 6 hours of reaction time at 100°C in inert conditions. The catalytic activity was compared with the reaction without Pd(II) complexes.

A Schiff base, 3-(phenylimino)indolin-2-one, was successfully obtained from the condensation reaction of isatin and aniline in absolute ethanol with a yield of 72%. The ligand was successfully characterized via physical and spectroscopic techniques namely melting point, Elemental Analysis (C, H, N), 1H Nuclear Magnetic Resonance (NMR) and Fourier Transform Infrared (FTIR) Spectroscopy. The corrosion inhibiting property of the Schiff base and that of a mixture of its starting materials on mild steel in 1 M HCl solution was studied through Electrochemical Impedance Spectroscopy (EIS) and Linear Polarization Resistance (LPR). The concentration of the Schiff base and the precursor molecules were varied from 1 x 10-3 M to 1 x 10-5 M. The results showed that the percentage of inhibition efficiencies increased with the increase of compound’s concentrations. Comparing the two sets of results for the Schiff base and the mixture of its starting materials, it was shown that the Schiff base was a much better inhibitor than the mixture of the starting materials, clearly indicating the importance of the presence of imine group (C=N) bearing lone pairs of electrons and π electrons in corrosion inhibition.

Electrodeposition was carried out on mild steel surface in 0.3 M sodium hydroxide solution (70% distilled water: 30% ethanol) containing 0.1 M salicylideneaniline using cyclic voltammetry and chronoamperometry techniques. Both techniques show the formation of the films on the mild steel surface. The corrosion behavior of electrodeposited mild steel was studied using electrochemical impedance spectroscopy (EIS) technique at various immersion times in 0.5 M sodium chloride solution (NaCl). The study indicates that the resistance of mild steel against corrosion increases after being electrodeposited with salicylideneaniline. However the films tend to diminished after 24 hours being immersed in 0.5 M NaCl solution.

In the present work, a polydentate Schiff base ligand (SB) was synthesized via condensation reaction between o-vanillin and Cl-m-phenylenediamine. Dinuclear complexes of Co(II) and Cu(II) were prepared by conventional method with SB:metal ratio of 1:1 whereas tetranuclear complexes were obtained via microwave-assisted synthesis with SB:metal ratio of 1:2. Characterization was carried out through elemental analysis (C,H,N), molar conductivity, magnetic susceptibility, Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR) spectroscopy. The experimental data indicated that the metal ions of the dinuclear and tetranuclear complexes were coordinated to the ligand through azomethine nitrogen, methoxy oxygen and deprotonated phenolic oxygen. The effective magnetic moment values of Co(II) complexes suggested tetrahedral geometry with 3 unpaired electrons. The shifting of n(C=N), n(C-O)phenolic and n(C-O)methoxy band to lower frequencies in all complexes indicated that coordination to metal centres occurred through these moieties. New weak peaks in the region 436 -559 cm-1 were assignable to n(M-N) and n(M-O). SB and its complexes were screened to be positive for anticancer activities against human colon cancer cell (HCT116). Tetranuclear Cu4SB and Co4SB metal complexes revealed IC50 values of 4.2 and 6.87, respectively; indicated to be more potent anticancer agents than the dinuclear counterparts and the parent ligand.

This paper reports the synthesis and characterization of three salophen ligands; 2,2'-((1E,1'E)-(1,2 phenylenebis(azanylylidene))bis(methanylylidene))diphenol [L1H], 2,2'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis (methanylylidene))bis(4-chlorophenol) [L1C] and 2,2'-((1E,1'E)-(1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(4-methoxylphenol) [L1OME]. The compounds were prepared from condensation reaction between salicylaldehyde, and its derivatives, with ortho-phenylenediamine. Their palladium(II) complexes, namely PdL1H, PdL1C and PdL1OME were synthesized through insertion reaction between the ligands with palladium(II) acetate. All compounds were characterized through melting point, elemental analysis, infrared spectroscopy, 1H and 13C NMR spectroscopy. Palladium(II) complexes were tested as homogenous catalysts in copper-free Sonogashira coupling reaction between iodobenzene and phenylacetylene in DMSO using triethylamine as base with 1.0 mmol% catalyst loading. The most performing catalyst was PdL1OME with 91% conversion followed by PdL1H (83%) and PdL1C (27%).

Electro-oxidation of 4-hydroxybenzalaniline in alkaline solution on mild steel surface was successfully carried out using cyclic voltammetric technique. Results demonstrated that brownish colour appeared on the mild steel surface after the cycle of voltammetric study. The presence of film was confirmed by the EIS measurement whereas the Nyquist plots obtained from EIS measurements were fitted with suitable electrical equivalent circuit. The coated mild steel exhibit better polarization resistance than uncoated mild steel.

Complexes of Pd(II) and Ni(II) have been synthesized with general composition ML2X2 (M =Pd(II), Ni(II); L = benzylsalicylideneimine and X = OCH3, F). All synthesized compoundshave been characterized using elemental analysis, magnetic susceptibility measurements,infrared and NMR spectral studies that led to the conclusion that the ligands act as bidentatemanner to form square planar geometry for all complexes. As an extending work, the modeldevelopment of these complexes using multilayer feedforward neural network wereperformed. NiL1d, PdL1d, NiL1c and PdL1c were fed to the training network as inputs andbacteria as output. Levenberg Marquardt training algorithm was used during the networktraining with 10 nodes in hidden layer. The results of testing network showed that theregression, R is 1, indicating that the developed model is good. This is supported by the small mean square error (MSE) is 1.948x10-28 at epochs 5. The finding in this study is significant, thus contributed to the design of antibacterial agent especially to the bidentate Schiff base complexes.Keywords: Schiff base, palladium(II), nickel(II), antibacterial, regression, neural network.

Schiff base compounds, namely, N,N′-dibensylideneethane-1,2-diamine (baen), N,N′-bis(4-chlorobenzylidene)ethane-1,2-diamine (cbaen), N,N′-bis(4-methyl benzylidene)ethane-1,2-diamine (mbaen) and 4-(((2-4-hydroxybenzylidene amino)ethylimino) methyl)phenol (hbaen) were tested as corrosion inhibitors on mild steel in 1M HCl via polarisation method. These compounds were synthesised from the corresponding substituted benzaldehydes and ethylenediamine. Results indicate that the presence of chloro, methyl and hydroxyl substituents enhance the inhibitive properties of N,N′-dibensylideneethane-1,2-diamine. Cbaen achieved the highest inhibition efficiency of 80·76% at 1 × 10–3 M.

Attenuated total reflectance–Fourier transformed infrared spectroscopy measurement is employed to study the interactions between the components of 30% methyl-grafted natural rubber (MG30), lithium trifluromethanesulfonate (LiCF3SO3 or LiTF), and propylene carbonate (PC). Vibrational spectra data of LiTF reveals that the νs(SO3) at 1,045 cm−1, δs(CF3) at 777 cm−1, and C=O stretching mode at 1,728 cm−1 for MG30 have shifted to lower wave numbers in MG30–LiTF complexes indicating that complexation has occurred between MG30 and LiTF. The solvation of lithium ion is manifested in Li+ ← O=C interaction as shown by the downshifting and upshifting of C=O mode at 1,788 to 1,775 cm−1 and νas(SO3) at 1,250 to 1258 cm−1, respectively, in LiTF–PC electrolytes. There is no experimental evidence of the interaction between MG30 and PC. Competition between MG30 and PC on associating with lithium ion is studied, and the studies show that the interaction between MG30–LiTF is stronger than that of the PC–LiTF in plasticized polymer–salt complexes. The effect of PC on the ionic conductivity of the MG30–LiTF system is explained in terms of the polymer, plasticizer, and salt interactions. The temperature dependence of conductivity of the polymer films obeys the Vogel–Tamman–Fulcher relation. Values of conductivity and activation energy of the MG30-based polymer electrolyte systems are presented and discussed.

Plasticized polymer electrolytes composed of poly(methylmethacrylate) (PMMA) as the host, propylene carbonate (PC) or ethylene carbonate (EC) as a plasticizer and LiX (X: CF 3 SO 3 − or N(CF 3 SO 2 ) 2 − ) as a salt were prepared by the solution cast technique. Impedance spectroscopy was performed in the temperature range between 303 and 383 K. In this paper, we report the electrical properties of polymer electrolytes with different lithium salts and plasticizers. The polymer electrolytes investigated exhibited high ionic conductivity at room temperature in the range of 10 − 6 to 10 − 4 S cm − 1 . The temperature dependence studies showed that the samples were ionic conductors and seemed to obey the Vogel–Tamman–Fulcher (VTF) rule. FTIR spectroscopy studies confirmed the polymer–salt interaction.

This research aims to apply and find out the characteristics of Problem-Based Instrumental Analysis of Chemistry Lab Work Learning Model (IACLLM) which is able to build the characters, improve the conceptual mastery and the ability of problem solving. The research using experimental quasy with 2 student groups of pre service chemistry teachers as the subjects of the research applied the treatment of problem-based IACLLM for the experimental class and lab work learning with standard lab work procedure in control class. Conceptual mastery was measured using essay test; problem solving skills were measured using assessment of problem solving reports, presentation of the results, and kit making products; whereas the emerged characters were observed during the learning process. The result of this research showed that problem-based IACLLM had open-ended problem characteristic, had produced local material kit, and characters were observed in every stage of problem-based learning model. The implementation of the model could improve the spectrometric and electrometric conceptual mastery, the problem solving skills on a very good level and also some characters were developing during learning process, including religious, discipline, honest, curious, creative, critical, cooperative, communicative, independent, and able to appreciate other people’s opinions and achievements, leadership, democracy, and able to be thorough and careful, and hardworking.

Polymer electrolytes composed of poly(methylmethacrylate) as a host polymer and lithium triflate as a salt have been prepared by solution cast technique. Polymer salt complexation has been confirmed by attenuated total reflectance Fourier transform infrared spectral studies. The ac conductivity as a function of temperatures in the frequency range 100 Hz–1 MHz has been carried out. The conductivity–temperature plots found follows the Arrhenius rule. The complex permittivity ϵ* and complex electric modulus M* have been analysed. The dispersion observe at low frequency is due to the space charge effect arising from the electrodes. The modulus spectra reveal that the dispersion deviates from the Debye behaviour. The ionic conductivity relaxation is determined from the maximum of the peaks of the dielectric loss modulus associated with the ac activation energy for ion relaxation E fp=0·337 eV, which agrees well with the dc conduction activation energy E A=0·341 eV. Thus, it is suggested that the dynami...