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Abstract: Phase behavior of sodium oleate (NaOl)/isoamyl alcohol‐based lamellar gel phase in cedar oil/water medium in the presence of the nonionic polymer hydroxyethyl cellulose (HEC) and its hydrophobic modified product (HMHEC) is investigated for the development of polymer‐embedded surfactant gels. HMHEC is more soluble in oil‐in‐water (o/w) microemulsions, but nonionic HEC shows limited solubility in the lamellar microemulsion (o/w type). Quantitative estimation of rate of adsorption of the polymer on lamellae bilayers can be easily done by Sudan solubilization and methylene blue complexation methods. Addition of HMHEC to the lamellar gel phase increases the polymer solubilization limit of lamellar gels as well as the viscoelasticity and thermal stability. The polymer‐embedded microemulsion gel acts as a “clean gel” since it exhibits good solubilization in different hydrocarbon media at ambient conditions. Elastic modulus of the polymer‐embedded gel influences directly the suspension performance of gels at high temperature and yields a reasonable sand‐settling velocity acceptable according to fracturing standards. The thermal characteristics and viscoelastic properties of polymer‐embedded gel were found to be suitable for moderate‐temperature reservoir stimulation where the bottom hole temperature is in the range 70–75 °C. Already a large amount of experimental data on pure microemulsions (without polymer) exists. Our studies indicate that the developed polymer‐embedded microemulsion gel has great potential as a model system for the study of polymer–microemulsion interactions. [ABSTRACT FROM AUTHOR]

A detailed study has been done on the rheological properties of sodium oleate based hydrogels that are developed in the presence of organic and inorganic salts. Shear stability of the NaOL gels were found to be a strong function of the salt, alkali, and the fabrication conditions. The addition of alkali to NaOL/KCl hydrogel enhanced the viscoelastic properties, which were observed from static and dynamic rheological tests. The hydrogel is miscible with hydrocarbon and can act as a clean gel during a postfracturing job. The quantitative estimation of migration of NaOL to microemulsion medium during gel break test can be done by Sudan dye solubilization and Methylene blue complexation methods, and the results show that the addition of both KCl and NaOH favors NaOL micelle growth and its partitioning tendency toward the hydrocarbon phase. [ABSTRACT FROM AUTHOR]

Metalladiazamacrocycles, coordination driven potential supramolecular host systems, can be obtained via cyclic linkages of the metal ions and the bridging ligands, N-acylsalicylhydrazides. The nuclearity and the shape of the metallamacrocycles could be modulated by controlling the steric interactions caused by N-acyl tails of the ligands. The macrocycles could be utilized for recognition of small organic guest molecules using their hydrophobicity/hydrophilicity, the size and shape/symmetry of the cavities. In addition, these macrocycles can be used as the supramolecular building blocks for the construction of systematically tuned metal-organic frameworks since these clusters have several replaceable solvent sites which could serve as connecting nodes for the formaton of network structures. [ABSTRACT FROM AUTHOR]

Abstract: A three-dimensional supramolecule of [Cu(3,2,3-tet)] n {[Ag2(CN)4]} n (1), (3,2,3-tet = N,N′-bis(3-aminopropyl)ethylenediamine), in which [Cu(3,2,3-tet)]2+ cations are suspended in the two-dimensional anionic networks composed of [Ag2(CN)4]2+ building blocks, was synthesized and characterized by X-ray crystallography. Every silver(I) ion is five-coordinated including the silver–silver interaction in anionic network. Variable temperature magnetic susceptibility data indicate weak antiferromagnetic interaction (−0.378cm−1) between copper(II) ions in 1. [Copyright &y& Elsevier]

Hexanuclear, octanuclear, and decanuclear manganese metalladiazamacrocycles have been prepared by reacting a series of pentadentate ligands, N-acylsalicylhydrazides (N-(3-methylbutanoyl)salicylhydrazide (H33-mbshz), N-(phenylacetyl)salicylhydrazide (H3pashz), N-(3,3-dimethylbutanoyl)salicylhydrazide (H33-dmbshz), N-(2-methylpropanoyl)salicylhydrazide (H32-mpshz), N-((R,S)-2-methylbutanoyl)salicylhydrazide (H3RS-2-mbshz), N-((S)-2-methylbutanoyl)salicylhydrazide (H3S-2-mbshz), and N-(2,2-dimethylpropanoyl)salicylhydrazide (H32-dmpshz)), with manganese(II) acetate tetrahydrate. The self-assembled, supramolecular complexes assume a nearly planar cyclic structure with an -(Mn-N-N)n backbone and measure ∼2.1, ∼2.3, and ∼2.6 nm in outer diameters for n = 6, 8, and 10, respectively. The chiralities of the manganese centers on the metalladiazamacrocycle occur in alternating ⋯ΛΔΛΔ⋯ configurations. While β-branched N-acylsalicylhydrazides (H33-mbshz, H3pashz, H33-dmbshz) with a sterically flexible Cα methylene group yield 18-membered hexanuclear manganese metalladiazamacrocycles of S6 point group symmetry, α-branched N-acylsalicylhydrazides lead to 24-membered octanuclear manganese metalladiazamacrocycles or 30-membered decanuclear manganese metalladiazamacrocycles depending on the size of the N-acyl substituents. The α-branched H32-mpshz ligand with the sterically least demanding isopropyl tail at the N-acyl position yields a 24-membered octanuclear manganese metalladiazamacrocycle of S8 point group symmetry, but other α-branched N-acylsalicylhydrazides such as H3RS-2-mbshz, H3S-2-mbshz, and H32-dmpshz lead to 30-membered decanuclear manganese metalladiazamacrocycles of S10 point group symmetry. The magnetic properties of the metalladiazamacrocycles are characterized by a weak antiferromagnetic exchange interaction, with Jeff = -8.5 to -3.8 K between the Mn3+ ion spins with S = 2 in the cyclic system. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of tridentate ONS donor ligands H2L1, H2L2 and H2L3 (H2L1 =2-hydroxyacetophenone hexamethyleneimine-3-thiosemicarbazone; H2L2 =2-hydroxyacetophenone morpholine-3-thiosemicarbazone; H2L3 =2-hydroxyacetophenone N(4)-methyl, phenyl thiosemicarbazone) with Mn(OAc)2 ·4H2O afforded manganese(IV) complexes of the type [MnL2] in an ethanol–methanol mixture under air. The crystal structure of Mn(L2)2 ·0.25H2O reveals an octahedral geometry with the ligand coordinated in a meridional fashion. The molecule is packed in the crystal lattice with extended hydrogen bonding networks. EPR spectra of the complexes in frozen solution at 77K show a weak signal at g ≈4 and a strong sextet at g ≈2 consistent with manganese(IV) in an octahedral environment. Cyclic voltammetry in DMSO/ dichloromethane show quasi-reversible peaks corresponding to the Mn(IV)/Mn(III) redox couple. [Copyright &y& Elsevier]

The spectral studies and structure of a ternary complex of copper(II) with 2-hydroxyacetophenone 3-hexamethyliminylthiosemicarbazonate (L2−) and 1,10-phenanthroline (phen) are reported. The thiosemicarbazone binds to the metal as a dianionic ONS-donor (L2−) ligand, and forms a complex of the stoichiometry [CuLphen]. The copper(II) complex was characterized by IR and UV/Vis spectroscopies, as well as by solid state room-temperature magnetic susceptibility. Spin Hamiltonian and bonding parameters of the compound are calculated from the EPR spectra. Computer simulation of EPR spectrum in DMF at 77 K aided the calculation of magnetic and bonding parameters of the compound. The structure of the compound is solved by single crystal X-ray diffraction. The geometry around copper is distorted square pyramidal. [Copyright &y& Elsevier]

An interesting series of eight neutral ternary Co(III) complexes of 2-hydroxyacetophenone N(4)-substituted thiosemicarbazones (H2L), bidentate heterocyclic bases 2,2′-bipyridine (bipy)/1,10-phenanthroline (phen) and azide with a general formula [MLB(N3)] were prepared. The complexes were characterized by means of spectroscopic methods. The coordination geometry around Co(III) in all the complexes is distorted octahedral with one dibasic tridentate ligand L2−, one bidentate heterocyclic base and one terminally coordinated azide group. Crystal structure of the compound CoL4bipyN3 was completely solved. All the electronic transitions were assigned. All complexes were diamagnetic indicating cobalt in a d6 strong field. [Copyright &y& Elsevier]

A coordination driven Pd2LIG4 self-assembly is synthesized using a new semi rigid dipodal ligand. [ABSTRACT FROM AUTHOR]

The article provide information on the study concerning the construction of cyclic molecules in the U.S. The author infers that the construction of cyclic molecules has obtained much attention because of both scientific curiosity and their potential use in applications such as magnetic materials, sensors for small molecules, and new classes of catalysts.

A Pd6L8 type coordination driven self-assembly was constructed using a tripodal ligand L (L = N1,N3,N5-trimethyl-N1,N3,N5-tris[(pyridin-4-yl)methyl]-1,3,5-benzene tricarboxamide) and palladium nitrate. The self-assembly was fully characterised using one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance spectroscopy, electrospray ionization-mass spectroscopy, thermogravimetric analysis, energy-dispersive X-ray spectroscopy and elemental analysis. Use of high resolution transmission electron microscopy (HR-TEM) analysis confirms the discrete nature of the assembly with a dimension of ∼2.8 nm, consistent with the density functional theory optimised structure. The assembly acts as an efficient homogeneous catalyst for a copper and phosphine free Sonogashira reaction under mild and aerobic conditions in aqueous medium. The catalyst shows equal efficiency for both electron deficient and electron rich aryl iodides and bromides and is also suitable for use with aliphatic alkynes. The utility of the catalyst as a reusable heterogeneous catalyst in toluene was assessed up to the 3rd cycle without any significant loss of catalytic activity. [ABSTRACT FROM AUTHOR]

In the title centrosymmetric binuclear complex, [V2(C17H17N4S)2O4], pairs of V atoms are linked by two oxo bridges. The coordination geometry at each VV atom is distorted octa­hedral, involving a pyridine N atom, a thiol­ate S atom, an azomethine N atom from the 1-[phen­yl(2-pyrid­yl)methyl­ene]-2-(pyrrolidin-1-ylthio­carbon­yl)hydrazine(−) ligand, and one terminal O and 2 bridging O atoms. The crystal structure is stabilized by weak inter­molecular C—H⋯O inter­actions. [ABSTRACT FROM AUTHOR]

A Pd 2 L 4 type supramolecular coordination driven self assembly was constructed using a dipodal pyridyl terminal ligand L [ L = N 2 , N 6 -dimethyl- N 2 , N 6 -bis((pyridin-4-yl)methyl)naphthalene-2,6-dicarboxamide] and palladium nitrate. The self-assembly was fully characterized by 1D and 2D NMR, ESI-MS, IR, TGA, HR-TEM and elemental analysis. The geometry optimization was performed using the Hartree–Fock method. The assembly acts as an efficient, reusable, heterogeneous catalyst for Buchwald–Hartwig amination reaction in toluene under phosphine free condition and aerobic medium. [ABSTRACT FROM AUTHOR]

A supramolecular compound, catena-poly{[Cu2(1,3-μ2-(1 a))2(μ2-ter)2(H2O)2] n·(6H2O) n} (1) has been synthesized using (1 a) [(1 a = N1, N3, N5-trimethyl- N1, N3, N5-tris((pyridin-4-yl)methyl)-1,3,5-benzene tricarboxamide] and terephthalate (ter) as the pillaring unit by self-assembly. The terephthalate units are connected by copper(II) ions forming a single strand, while a pair of such strands are then linked by (1 a) via two pyridyl terminal arms bound to copper(II) nodes on either side forming a one-dimensional double stranded assembly propagating along the c axis. The compound crystallizes in the Fdd2 space group. The cavity created in the interior of this double strand assembly trap six water molecules and are stabilized by hydrogen bonding with the host. The arrangement of the pair of acyclic water trimers in isolated cavities of (1) is such that it resembles a closed-bracket-like formation. The Hirshfeld surface analysis of (1) reveals the presence of strong intermolecular hydrogen-bonding interactions between one-dimensional ladder-like units and with the water trimer in the host cavity. The copper(II)-containing coordination polymer also acts as an efficient catalyst for the Glaser-Hay homo-coupling reaction. [ABSTRACT FROM AUTHOR]

A trinuclear copper complex [Cu3(napxshz)2(phen)2] has been synthesised using a tribasic naproxen‐appended ligand [H3napxshz = 2‐hydroxy‐N′‐(2‐[6‐methoxynaphthalen‐2‐yl] propanoyl) benzohydrazide] and 1,10‐phenanthroline. The complex was characterised by different spectroscopic methods such as Fouriertransform infrared (FT‐IR), ultraviolet‐visible (UV–Vis) and electrospray ionisation (ESI)‐mass spectroscopy. The solid‐state structure of the ligand and complex 1 was established by single‐crystal X‐ray diffraction analysis. The interaction of the complex and the ligand with DNA was investigated by UV–visible spectroscopy and fluorometric titrations. The calculated binding constants (Kb) of the complex and the ligand with ct‐DNA show that the complex has a higher binding affinity than the ligand H3napxshz. Quantum chemical calculations were performed to understand the structural aspects of the complex and its interactions with DNA. The molecular docking study reveals the interaction between DNA, and the complex is in intercalative mode. [ABSTRACT FROM AUTHOR]

A dibasic tetradentate N3O3 Schiff base ligand {(Z)-2-hydroxy-N′-((8-hydroxyquinolin-2-yl)methylene)benzohydrazide}(H3L) and its binuclear phenoxido-bridged gadolinium complex, [Gd2(HL)2(NO3)2(DMF)4], were synthesised. The ligand was characterised by 1H-NMR, ESI-Mass, FT-IR, and UV–visible spectroscopic methods. The gadolinium complex was characterised by FT-IR, UV–visible spectroscopy, and single-crystal X-ray diffraction. The central gadolinium(III) ion is nine-coordinated, with a distorted tri-capped-trigonal-prismatic geometry. The equatorial coordination sites are satisfied by donor atoms such as phenolate oxygen in μ2 bridging modes, quinoline nitrogen, azomethine nitrogen from the 8-hydroxyquinoline-2-carbaldehyde and one carbonyl oxygen of salicyl moiety. In addition, two DMF molecules via their carbonyl oxygens and one nitrate in a bidentate fashion via O1 and O2 in the axial region complete the coordination. The gadolinium ions are separated by a distance of 4.04 Å in the complex. The Photoluminescence properties of the ligand and the gadolinium complex were studied in the solid-state at room temperature. [ABSTRACT FROM AUTHOR]

Abstract: An unusual copper(II) complex [Cu(L1a)2Cl2] CH3OH·H2O·H3O+Cl− (1a) was isolated from a solution of a novel tricopper(II) complex [Cu3(HL1)Cl2]Cl3·2H2O (1) in methanol, where L1a is 3-(2-pyridyl)triazolo[1,5-a]-pyridine, and characterized with single crystal X-ray diffraction study. The tricopper(II) complex of potential ligand 1,5-bis(di-2-pyridyl ketone) carbohydrazone (H2L1) was synthesized and physico-chemically characterized, while the formation of the complex 1a was followed by time-dependant monitoring of the UV–visible spectra, which reveals degradation of ligand backbone as intensity loss of bands corresponding to O→Cu(II) charge transfer. [Copyright &y& Elsevier]

A novel S4-symmetric icosanuclear manganese metalladiazamacrocycle was synthesized using a pentadentate ligand, N-3-phenyl- trans-2-propenoylsalicylhydrazide (H3L), that has a rigid and bulky terminal N-acyl group. A 20 cyclic repeat of an -(Mn-N-N)- linkage resulted in a highly puckered diaza-bridged 60-membered icosanuclear metallamacrocycle. The steric interaction between the ligands in the cyclic system leads to five consecutive MnIII centers in a chemically different -(MnAMnBMnCMnDMnE)- environment, with the chiralities of the metal centers being in a rather complicated -(ΛΛΔΛΛ)(ΔΔΛΔΔ)- sequence. [ABSTRACT FROM AUTHOR]

Discusses the coordination chemistry of thiosemicarbazones, due to their interesting physicochemical and biological properties. Means in which the thiosemicarbazones act as chelating ligands with copper (II) ion; Arrangement of two inversion-symmetry-related monomers; Coordination of the azomethine nitrogen atom to the central copper (II) ion.

A manganese-based coordination polymer, [Mn2L2(µ-MeOH)2]n (H2L = 2-hydroxy-1-naphthaldehyde isonicotinoylhydrazone) was obtained by self-assembly of 2-hydroxy-1-naphthaldehyde isonicotinoylhydrazone and manganese(II) acetate. The coordination polymer was characterized by IR, EPR and UV–Vis spectroscopy. The single-crystal X-ray diffraction study reveals that the dibasic tridentate ligand (L2−) is bound via ONO donor sites to manganese(II). Two such [ML] fragments are connected by µ2-bridged methanol (MeOH) to form a di-manganese species. The sixth site of each of the manganese is occupied by the pyridyl N atom of the isonicotinoyl group. This arrangement gives a polynuclear complex of the formula [Mn2L2(µ-MeOH)2]n. The coordination geometry of manganese is distorted octahedral. The X-band electron paramagnetic resonance (EPR) measurement of the complex at 77 K shows a six-line spectrum and a signal at the half field, with g = 4.88. The half-field signal indicates the dimeric nature of the complex in the solution state. The cyclic voltammetric measurement of the complex shows a reversible MnIII/MnII redox couple. The complex catalyzes the conversion of 3,5-di-tert-butyl catechol to the corresponding o-quinone with a catalytic turnover rate of (kcat) 27.22 h−1. [ABSTRACT FROM AUTHOR]

A Schiff-base compound, 2-((E)-1-(2-(dimethylamino)ethylimino)ethyl)phenol (HL), has been synthesized and characterized by different spectroscopic methods The chemosensor shows selective “turn–on” cyan colour fluorescence response to Al 3+ ion over a wide variety of other competing metal ions such as Zn 2+ , Cu 2+ , Co 2+ , Ni 2+ , Cd 2+ , Fe 2+ , Mg 2+ , Hg 2+ , Mn 2+ , Ca 2+ , Pb 2+ , Fe 3+ , Cr 3+ , Na + and K + . The fluorescence emission intensity at 462 nm displayed by the chemosensor, increases progressively during the addition of Al 3+ ion until saturation point, with over 20 fold intensity enhancement. Additionally, the linear range for the chemosensor has been found to be 0.5 × 10 −6 to 10 × 10 −6  mol/L, the detection limit of the chemosensor is 4.32 × 10 −6  M and the stability constant is 2.1 × 10 4  M −1 . Similar fluorescence behaviour is also observed in a variety of solvents and solvent mixtures in the presence of Al 3+ . The fluorescent emission has also been detected when a sample solution of HL containing Al 3+ is irradiated by UV light. UV–vis titration experiment has established that the chemosensor HL, binds to Al 3+ in 2:1 ratio. The Density Functional Theory (DFT) and Time Dependent-Density Functional Theory (TD–DFT) calculations were performed on HL, L − and its aluminium complex which give insight into the geometric, electronic, thermodynamic and optical properties of chemosensor-Al 3+ interactions. [ABSTRACT FROM AUTHOR]

Two hydrazide derivatives namely N ′-(4-Hydroxybezylidene)nicotinic hydrazone (HBNH) and N ′-(4-methylybezylidene)nicotinic hydrazone (MBNH) have been investigated as corrosion inhibitors for mild steel in 1 M HCl using electrochemical, weight loss, FE-SEM, AFM, quantum chemical calculation and molecular dynamic simulation methods. They show good corrosion inhibition efficiency; with the inhibition efficiency of MBNH being higher than that of HBNH. The polarisation results indicate that both the inhibitors act as mixed type inhibitors. They follow Langmuir adsorption isotherm. Quantum chemical parameters of the inhibitors have been calculated using DFT method. Interaction energies derived from molecular dynamics simulation are in agreement with experimental results. [ABSTRACT FROM AUTHOR]

An interesting series of four complexes of acenaphthoquinone 3-(4-benzylpiperidyl) thiosemicarbazones (HL), with a general formula [Co II L 2 ]( 1 ), [Ni II L 2 ]( 2 ), [Cu II L 2 ]( 3 ), and [Zn II L 2 ]( 4 ), were prepared. The complexes were characterized by means of elemental analysis, IR, UV–Vis spectroscopy and ESI-MS methods. In all the complexes the ligand (HL) coordinate as a monobasic ligand in tridentate fashion. The crystal structure of the compounds 1 and 2 were determined by single crystal X-ray diffraction experiment. The geometry and bonding parameters of the compound 3 were determined from EPR spectra. The g values of 3 , calculated from EPR at 77 K, indicate a rhombic coordination geometry about copper(II). The room temperature magnetic moment of the cobalt(II) complex 1 , indicate that it is in high spin state, while the nickel(II) complex, 2 , is paramagnetic. The redox behavior of the ligand and its complexes were studied by cyclic voltammetry. The density functional theory (DFT) was used for geometry optimization, determination of HOMO and LUMO energies, HOMO–LUMO energy gap and dipole moment of the compounds. Antibacterial activity of the ligand and complexes 1 – 4 , have been screened against two gram negative bacteria Escherichia coli , Pseudomonas aeruginosa and two gram positive bacteria Staphylococcus aureus and Bacillus subtilis. The electron micrograph images display damage to microbial cell wall upon treatment with the compounds. [ABSTRACT FROM AUTHOR]

Three novel trinuclear Ni(II) complexes, [Ni 3 (L 1 ) 2 (py) 4 ] ( 1 ), [Ni 3 (L 2 ) 2 (H 2 O) 2 (DMA) 2 ] ( 2 ) and [Ni 3 (L 3 ) 2 (py) 4 ] ( 3 ), with trianionic pentadentate ligands derived from salicylhydrazide with N-acyl substituents [H 3 L 1 = N 2 -crotonoylsalicylhydrazide, H 3 L 2 = N 2 -(3,3-dimethylacryloyl)salicylhydrazide, H 3 L 3 = N 2 -cinnamoylsalicylhydrazide] were synthesized and characterized by elemental analysis, spectroscopic techniques, like UV–Vis, FT-IR and NMR, molar conductivity and magnetic susceptibility measurements, and single crystal X-ray diffraction. The solid state structures of the complexes reveal the binding modes of the different ligands via ONO donor atoms. Complex 1 crystallises in the triclinic system while complexes 2 and 3 crystallise in the monoclinic system with space groups P 1 ¯ ( 1 ) and P 2 1 / c ( 2 and 3 ). Computational studies were performed using Density Functional Theory (DFT) to obtain physical properties of all three complexes. The ligands and their metal complexes were screened for antibacterial activity to assess their inhibition potential against two Gram positive bacteria; Staphylococcus aureus and Bacillus subtilis and two Gram negative bacteria; Escherichia coli and Pseudomonas aeruginosa by the well diffusion method using gentamicin as a positive control. Antibacterial screening data reveals that the trinuclear Ni(II) complexes have significantly enhanced inhibitory activities compared to the ligands. [ABSTRACT FROM AUTHOR]

A novel chemo-sensor based on diaminobenzidine (H 2 L) was synthesized and characterized. The chemo-sensor shows selective “turn-on” fluorescence response to Zn 2+ ion over a variety of other competing metal ions such as Al 3+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Cu 2+ , and Cd 2+ . The strong fluorescent emission can be observed even at ppm level concentration of the probe in the presence of Zn 2+ with over 54 fold intensity enhancement at 509 nm. Similar fluorescence behaviour is also observed in a variety of solvents and solvent mixtures in the presence of zinc(II). The fluorescent emission is also detected when the H 2 L sample solution containing Zn 2+ is exposed to UV radiation. The sensitive nature of fluorescent response of the probe to Zn 2+ is gauged from the very low detection limit of 8.6 × 10 −9 M. The chemo-sensor H 2 L binds to zinc(II) in 1:1 stoichiometry as determined by Job's plot and the binding constant is calculated as 7.8 × 10 4 M −1 . [ABSTRACT FROM AUTHOR]

The complex compound of zinc(II) supported by (Z)-2-hydroxy-N′-(1-oxoacenaphthylen-2(1H) ylidene)benzohydrazide ligand (H 2 L 1 ) has been reported and discussed. The reaction of zinc acetate with H 2 L 1 ligand leads to the formation of a mononuclear zinc(ii) complex, [Zn(HL 1 ) 2 H 2 O]. The ligand, H 2 L 1 has been characterized by elemental analysis, 1 H, 13 C and 1 H COSY -NMR, IR and ESI-MS, while the complex was characterized by elemental analysis, IR, and ESI-MS. The crystal structures of the free ligand H 2 L 1 and the complex have also been determined by single crystal X-ray diffraction. The ligand chelates with metal centre with a nitrogen atom of imino moiety and an oxygen atom of enolic group. The complex shows distorted trigonal bipyramidal geometry around the metal centre with oxygen atoms lying in the equatorial plane and imino nitrogen atoms along the axial direction. The DFT/TD-DFT calculations were performed on both the ligand and its zinc complex to get insight into the structural, electronic and optical properties. The photoluminescence, fluorescence properties of the complex have been investigated. [ABSTRACT FROM AUTHOR]

An abstract of the study "A Coordination Driven Supramolecular Pd2L4 Self-Assembly as Heterogeneous Catalyst for Buchwald-Hartwig Amination Reaction" by S. Pradhan and colleagues is presented.

4(N,N-dimethylamino) benzaldehyde nicotinic acid hydrazone is prepared and investigated as corrosion inhibitor for mild steel in 1 M HCl using weight loss, electrochemical method, quantum chemical calculation, FE-SEM and AFM method. The inhibition efficiency increases with increasing inhibitor concentration. The polarisation study indicates that it acts as a mixed type corrosion inhibitor. The adsorption of inhibitor is spontaneous and obeys the Langmuir's adsorption isotherm. The FE-SEM images and AFM images of mild steel support strong adsorption and high inhibition efficiency of the inhibitor. Quantum chemical parameters are also in agreement with experimental obtained efficiency. [ABSTRACT FROM AUTHOR]

• The chemosensor (H 3 L) showed high selectivity for Al3+ ion. • The binding ratio of H 3 L:Al3+ was obtained as 2:1 determined by the Job's plot and 1H NMR titration in solution phase. • DFT/TD-DFT calculations showed the stability of Al3+–complex. • The DFT/TD-DFT values for emission and electronic studies show good agreement with experimental values. A Schiff base chemosensor (H 3 L) based on the 4-(N,N-Diethylamino)salicylaldehyde moiety has been synthesized and characterized using several spectroscopic techniques i.e. 1H-NMR, FT-IR, Mass and UV-visible. The chemosensor shows high selectivity for Al3+ ion through 'turn-on' cyan colour fluorescence over a variety of metal ions i.e. Ni2+, Zn2+, Cd2+, Mn2+ ions except Co2+, Cu2+ and Fe3+ ions. The chemosensor exhibits 20 fold intensity enhancement at 481 nm (λ ex = 378 nm) against Al3+ ion until saturation point. Additionally, the detection limit and stability constant were found to be 1.2 × 10−6 M and 5.2 × 105 M−1, respectively with the low equivalent range of 1–34 µM. The chemosensor also displays similar fluorescence behaviour for Al3+ ion in a variety of solvents and solvent mixtures. The quantum yield (Ф F) values for H 3 L and Al3+–complex were observed to be 0.08 and 0.29, respectively. The Job's plot calculations show that, H 3 L binds to Al3+ ion in 2:1 ratio. 1H-NMR titration analysis indicates that the chemosensor undergoes mono-deprotonation while binding to Al3+ ion. The geometry of the chemosensor and Al3+–complex were optimised and some thermodynamic parameters were calculated using Density Functional Theory (DFT). The Gibbs free energy of complex was calculated to be -1272.00 kcal/mol. Further, the optical and electronic properties of the proposed complex were explained with the help of Time Dependent-Density Functional Theory (TD–DFT). [Display omitted] [ABSTRACT FROM AUTHOR]

Either an S8 symmetrical 48-membered hexadecanuclear or an S10 symmetrical 60-membered icosanuclear manganese metallamacrocycle was self-assembled using a manganese ion and a ditopic pentadentate ligand. This was either N-4-phenylbenzoylsalicylhydrazide (H3pbshz) containing a rigid rod-shaped, bulky biphenyl residue as a terminal N-acyl group or N-3,3-diphenylpropionylsalicylhydrazide (H3dppshz) containing a flexible β-branched N-acyl group, but with two sterically bulky phenyl residues at the Cβ position. The backbone of these metal-organic assemblies is a repeating unit consisting of a -[Mn-N-N-] link that extends to complete either the 48-membered cyclic structure involving 16 manganese(lll)centers and 16 ditopic linker ligands or the 60-membered cyclic structure involving 20 manganese(lll) centers and 20 ditopic linker ligands (depending on the ligand used). Even though the nuclearity of the metallamacrocycles was different, the successive manganese centers were in the same chiral sequence, ··· (ΛΛΛΛ)(ΛΛΛΛ)···. [ABSTRACT FROM AUTHOR]

Discrete metal-organic polyhedra (MOP) with nanosized cavities and/or clusters of MOP could be prepared when C3-symmetric facial ligands and a potential hexatopic Cu(II) ion are combined in the presence of perchlorate as a weak linker, while similar reaction conditions in the presence of a nitrate linker led to extended metal-organic frameworks made of MOP as supramolecular building blocks. [ABSTRACT FROM AUTHOR]

Abstract: Six new copper(II) complexes of 2-hydroxyacetophenone-N(4)-phenyl semicarbazone have been synthesized and physico-chemically characterized. The tridentate character of the semicarbazone is inferred from IR spectra. Based on EPR studies, the spin Hamiltonian and bonding parameters have been calculated. The g values, calculated for all the complexes in frozen DMF, indicate the presence of the unpaired electron in the orbital. The metal–ligand bonding parameters evaluated showed strong in-plane σ and in-plane π-bonding. The structure of the compound, CuLphen has been resolved using single crystal X-ray diffraction studies. The crystal structure revealed a monoclinic lattice with space group symmetry P21/c. The compound adopts a distorted square pyramidal geometry with a N2O2 core as the base. [Copyright &y& Elsevier]

A dinuclear doubly bridged copper(II) complex [Cu 2 L 2 ] where L represents N, N′-bis(3-ethoxysalicylidene)-4-methyl-1,3-phenylenediamine has been synthesised. The ligand was characterised by elemental analysis and spectroscopic techniques such as 1H NMR, 13C NMR, FT–IR, UV–visible and ESI–mass. The copper(II) complex was characterised using partial elemental analysis, FT-IR and UV–visible spectral techniques. The solid state structure of the complex was carried out using single crystal X-ray diffraction. The crystallographic study reveals that the two copper(II) metal ions are four coordinated (O 2 N 2) via phenolate O and azomethine N atoms, forming an unusual geometry between tetrahedral and square-planar. Cyclic voltammetry of complex reveals two consecutive quasi-reversible one electron redox couples corresponding to CuII–CuII/CuII–CuI and CuII–CuI/CuI–CuI. Density Functional Theory (DFT) and Time-dependent density functional theory (TD–DFT) calculations were carried out for the determination of the optimized structures. The theoretically obtained fundamental vibrational frequencies show good agreement with observed values. The ligand binds to Cu(II) in 1:1 stoichiometry as determined by Job's plot and the binding constant is calculated as 6.8 × 102 M−1 in solution phase. The photoluminescence property of the complex has also been investigated to understand its emission behaviour. Image 1 • A tetradentate m -phenylenediamine based ligand yields a dinuclear copper complex. • The strain involved during coordination introduces a distorted tetrahedral geometry. • UV-visible spectral titrations indicate a 1:1 binding ratio for Cu2+ and H 2 L. • · DFT/TD-DFT calculations demonstrate the stability of the binuclear copper complex. [ABSTRACT FROM AUTHOR]

The article examines the utilization of the C3-symmetric facial ligands and C4-symmetric metal ions for the preparation of truncated octahedral nanocages. The curvature needed for truncation at the octahedral vertices was accomplished using ligands with a tilted pyridyl group and a nitrogen donor atom. The nanocages have 12 ports at the edges of the truncated octahedron.