Octahedral Arrangement Research Articles

Nickel complexes of aroylhydrazone ligand: synthesis, crystal structure and DNA binding properties

In this work, three aroylhydrazone ligands ((E)-2-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL1; (E)-3-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL2; and (E)-4-hydroxy-N′-(1-(pyrazin-2-yl)ethylidene)benzohydrazide, HL3) and their complexes with nickel (Ni(L1)2, NiL1; Ni(L2)2∙2DMF, NiL2; Ni(L3)2∙2DMF, NiL3) were prepared. The single crystal X-ray structures analysis of three compounds showed that they were neutral. The ligand adopts tridentate chelating mode. The nickel ion is six-coordinate with two O atoms and four N atoms from two ligands, and forms an octahedral arrangement. The investigation of DNA binding ability by ultraviolet and fluorescence titrations showed that NiL2 and NiL3 exhibit moderate binding affinity toward calf Thymus DNA. Spectroscopy, molecular docking, and molecular dynamics simulation indicated that NiL2 and NiL3 bind at the minor groove of DNA through intercalation.

SYNTHESIS AND STUDIES OF SOME cis- MoO2(VI) COMPLEXES WITH NITROGEN DONOR MACROCYCLIC LIGANDS

According to what mention in research paper, the reaction of [MoO 2 (L)](acac) 2 with 1,3-diketones gives the formation of 1 MoO 2 (VI) complex of formulation [MoO 2 (L)](acac) 2 with a Schiff base, acquire from condensation of di-2-thienylethanedione with 2,3-diaminotoluene and four new complexes having formula [MoO 2 (ML)](acac) 2 . The each of the five dioxomolybdenum(VI) complexes synthesized were represented by thermal studies, elemental analyses, UV-Vis, molar conductance, IR and NMR and. The molybdenum metal has coordination number of 6. Each of the dioxomolybdenum(VI) complexes have geometry of octahedral arrangement. Distorted octahedral environment exist surrounding to molybdenum element in formed MoO 2 (VI) complexes. The ligand geometry was completed by two oxo O-atoms and four N-atoms. The synthesized complexes were show moderate activity versus S. aureus and S. typhi. The advancement inside the antibacterial activity being defined on the idea of chelation speculation.

Crystal structure and magnetic characterizationof μ6–oxo bridged Hexanuclear Fe(III) complex

In this study, the synthesis, X-ray crystal structure and magnetic properties of a new hexanuclear Fe(III) complex, 2[OFe6(thme)4Cl6].4[C6H15N].6[H2O] (1), (H3thme = 1,1,1-Tris(hydroxymethyl)ethane) is reported. The structure of 1 is described as the hexametalate core [OFe6(thme)4Cl6] consisting of an octahedral arrangement by four alkoxo oxygen atom from thme ligand, a terminal chloride atom and one μ6–oxo group at the center. Variable-temperature magnetic susceptibility measurements of 1 indicate an antiferromagnetic interaction between the Fe(III) centers.

Docking Approach to Predict Inhibition Activity of New Pt(II) Complexes Against Kinase Protein and Human DNA: Full Characterization, HF-FC Modeling and Genotoxicity

New series of Pt(II)–azaindazole complexes, were synthesized and also characterized by, analytical, spectral and computational tools. All synthesized Pt(II)-complexes, appeared as mononuclear with bi-dentate mode of bonding. Octahedral arrangement as well as square-planer, were proposed geometries around platinum atoms in all complexes. The best atomic-skeletons, were demonstrated by using Gaussian09 program. Applying MOE module (V. 2015), extensive molecular docking process was executed upon all new synthesizes. This docking study was interested in kinase protein (3ce3) and health cell–DNA (5ahr), to predict the degree of cancer-inhibition and also the mode of interaction. A significant inhibition activity, was clearly predicted with Pt(II)–4b and Pt(II)–4c complexes, against 3ce3 protein-receptors. While the absence of any significant effect towards 5ahr, which is favorable trend of therapeutic agent. Various backbone receptors (amino acids) were attacked through H-bonding, from most tested inhibitors, especially of 3ce3 protein. DNA-degradation study, which executed in vitro, displayed a complete degradation for DNA with most screened compounds except 4d and 4e derivatives. This feature points to the promising antitumor activity of most synthesizes, especially the Pt(II) complexes, as a predicted role of its complexes.

Biological evaluation, molecular docking and DNA interaction studies of coordination compounds gleaned from a pyrazolone incorporated ligand

In this work, we have synthesized a few novel mononuclear complexes of Cu(II), Co(II), Ni(II) and Zn(II) using a pyrazolone-derived Schiff base ligand. They were characterized by spectroscopic and analytical methods. The elemental analyses, UV-Vis, magnetic moment values and molar conductance of the complexes reveal that the complexes adopt an octahedral arrangement around the central metal ions. The interaction of complexes with CT-DNA was studied by absorption spectral titration and viscosity measurements. The observed data show that the complexes bind with CT-DNA via an intercalation mode. Efficient pUC18 DNA cleavage ability of the synthesized compounds was explored by gel electrophoresis. The antimicrobial activity of these compounds against a set of bacterial and fungal strains reveals that the complexes exhibit better activity than the free ligand. Moreover, all the complexes were evaluated against two cancer (HeLa and HepG2) and one normal (NHDF) cell lines. The data were compared with cisplatin. Anti–inflammatory activity has been experimentally validated which proves that theoretical predictions concur with the experimental results. In addition, molecular docking studies have been performed to consider the nature of binding mode and binding affinity of these compounds with DNA (1BNA) and protein (3hb5). These studies reveal that the mode of binding is intercalation and the complexes have higher binding energy scores than the free ligand.

Synthesis, Characterization for New Nanometric VO(II)–Thioacetanilide Complexes by, Spectral, Thermal, Molecular Computations and DNA Interaction Study Beside Promising Antitumor Activity

A novel series, of thioacetanilide derivatives (4a–e), was synthesized and fully characterized. Their corresponding VO(II) complexes, were prepared and inspected by all analytical, spectral and computational techniques. From IR spectral analysis, poly dentate mode of bonding, was proposed for all organic ligands towards two central atoms. The octahedral arrangement configuration, was suggested for all complexes, based on; UV–Vis, ESR and magnetic measurements. TGA and DTA analysis, built a good assertion on the presence of solvent molecules, attached with the complex particles. The molecular modeling technique, excreted the best structural forms for all tested compounds. Moreover, essential computational parameters were estimated, to verify the molecular formulae. Molecular docking study, was concerning with the inhibition feature against 3s7s and 3gcw proteins, belonging to breast and liver cancer cells, respectively. The computed parameters introduced a promising activity for some tested derivatives. Furthermore, the experimental antitumor screening for VO(II) complexes, versus HepG-2 and MCF-7 cell lines, displayed superiority for [(VO)2(SO4)2(AETA)(H2O)2]3H2O complex in comparing to cisplatin (standard drug). As well as, the genotoxicity results, coincide excellently with antitumor result.

Synthesis, characterization of binary and ternary copper(II)-semicarbazone complexes: Solvatochromic shift, dipole moments and TD-DFT calculations

A novel semicarbazone O2N donor ligand, HL, was synthesized by condensation of 2-aminochromone-3-carboxaldehyde with semicarbazide hydrochloride. The HL ligand is allowed to react with several copper(II) salts namely: AcO–, NO3–, SO42– and Cl–, in absence and presence of secondary ligand (SCN-, 8-HQ and 1,10-phen), forming binary and ternary copper complexes. Characterization of the compounds has been done using various techniques like elemental analyses, magnetic moments, conductance measurement, thermogravimetry and FT-IR, UV-Vis, 1H and 13C NMR, EPR and mass spectroscopy. The HL ligand acts as monoanionic O2N tridentate in most complexes, forming Cu(II) complexes with an octahedral and square planar geometrical arrangements. The compounds exhibit luminescence property; promising interesting potential applications as photoactive materials. The ground state (µg) and excited state (µe) dipole moments are estimated from solvatochromic shifts of absorption and fluorescence spectra as a function of the dielectric constant (Ɛ) and refractive index (n) by using Bilot–Kawski, Lippert–Mataga, Bakhshiev, Kawski–Chamma–Viallet and Reichardt correlation methods. Excited state dipole moment is observed as larger than the ground state dipole moment. The molecular structural parameters of the ligand and its Cu(II)- complexes have been calculated on the basis of DFT level implemented in the Gaussian 09 program at the B3LYP/6-31G(d,p) level and the theoretical data are correlated with the experimental data. The antibacterial properties of the ligand and its complexes have been screened against selected kinds of bacteria and fungi.

Synthesis, characterization, and crystal structures of iodides and polyiodides of scandium complexes with urea and acetamide

Iodides and polyiodides of scandium complexes containing urea (Ur) and acetamide (AA) have been synthesized and characterized by elemental analysis, IR spectroscopy, and X-ray diffraction. The trigonal crystals of [Sc(L)6]I3 (L = Ur, AA) and monoclinic crystals of [Sc(Ur)6][I3]3 are isomorphous to the earlier reported [M(Ur)6]I3 (M = Ti, V, Cr, Fe) and [Ln(Ur)6][I3]3 (Ln = Yb, Lu), respectively. Therefore, scandium in its complexes with urea and iodine links rows of 3d transition elements and rare-earth elements; it continues the tendency of formation of polyiodides with different structures from isomorphous iodides, which was found for other metal(III) urea complexes. In the orthorhombic crystals of [Sc(AA)6][I5][I3]I, the first example of the M(III) acetamide polyiodide, metal ions in complex cations are located at the centers of distorted octahedral arrangements of oxygen atoms of acetamide; iodide ions are not coordinated. The crystals of [Sc(AA)6][I5][I3]I contain V-shaped pentaiodide, linear triiodide, and isolated iodide anions.

Superior Sensor for Be2+ Ion Recognition via the Unprecedented Octahedral Crystal Structure of a One-Dimensional Coordination Polymer of Crown Fused Zinc Phthalocyanine.

The unprecedented one-dimensional (1-D) coordination polymer of crown fused zinc phthalocyanine (P-CfZnPc) with an octahedral crystal structure and with intermolecular packing that has superior multichannel sensor ability for Be2+ ion recognition was prepared and characterized by single-crystal X-ray diffraction analysis (XRD) and a wide range of spectroscopic and voltammetric methods. An exceptional feature of the crystal structure of P-CfZnPc is that each zinc ion in the phthalocyanine (Pc) polymer is coordinated by the four isoindole nitrogen atoms and an outer oxygen atom of the Pc molecule. This structure is the first example of an octahedral arrangement in a 1-D polymeric chain for zinc phthalocyanines (ZnPcs) and zinc porphyrins (ZnPs) reached without the presence of a coordinating solvent, which was confirmed by XRD analysis. Interestingly, this (1-D) coordination polymer preserves its conformation in THF (tetrahydrofuran) solution, thereby effectively preventing aggregation. This result was confirmed by the particle size of the molecule (125 nm) using dynamic light scattering (DLS) and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectra as well as UV-vis spectroscopy. The sensor has long-term stability (more than 3 months in solution), a very low response time (less than 1 s), and nonaggregating ability, facilitating the accurate determination of ultra-trace amounts of Be2+ (lower than 1 ppb), which is extremely important in terms of human health and environmental protection. The sensor can highly selectively and sensitively bind Be2+ among Li+, Na+, K+, Cs+, Mg2+, Ca2+, Ba2+, Al3+, Co2+, Hg2+, Ni2+, Pb2+, and Zn2+ ions via Be2+-induced J aggregation of Pc molecules. Such a binding leads to not only a significant decrease in Pc absorption (677 nm) as well as the creation of new absorption (720 nm) but also fluorescence emission quenching (690 nm). Furthermore, the sensor displayed highly selective voltammetric recognition for Be2+ following J aggregation/disaggregation in the second reduction process. The binding mechanism of the sensor and Be2+ ion was also explained on the basis of TD-DFT calculations.

Synthesis of new Cu(II)-benzohydrazide nanometer complexes, spectral, modeling, CT-DNA binding with potential anti-inflammatory and anti-allergic theoretical features

New nanometer Cu(II)-benzohydrazide complexes were synthesized and characterized. Mono negative tetra-dentate mode is the general feature proposed for all coordinating ligands. Variable structural forms were established, square-planer, tetrahedral and octahedral arrangements around copper centers. XRD and TEM studies displayed a nanometer size for crystalline compounds. TGA analysis of new complexes showed low thermal stability due to the presence of crystal water molecules. Kinetic parameters were calculated using two comparative methods for assertion. ESR study was performed on three chosen complexes to estimate essential spectral parameters and assert on proposed geometries. Gaussian09 software program and applying DFT/B3LYP method was used for optimizing all structures to give the best arrangement for atoms. Essential indexes were extracted from log files as well as other indexes were computed based on frontier energy gaps. Potential theoretical anti-inflammatory, antitumor and anti-allergic studies were executed using Autodock 4.2 tools. Essential energies were calculated over docking complexes corresponding to 5HN1, 5AV1 and 4H1L protein receptors for three pathogens (inflammation, liver cancer and allergy, respectively). H2L5 ligand displays significant activity towards inflammation and allergy diseases. Such potential feature will give a well insight about their biological attitude in future experimentation.

Synthesis, spectroscopic, and structural characterization of new functionalized gem-bisphosphonate complexes of tin(IV) chloride

Abstract Bisphosphonates of the types X(P(O)(OEt)2)2 (X = CH2= C (1a), CNCH2CH (1b) and PhCH2NCH2CH (1c)) react with SnCl4 in anhydrous dichloromethane to produce the new tin(IV) adducts [SnCl4(1a)] (2a), [SnCl4(1b)] (2b) and [SnCl4(1c)] (2c) in 72–80% yields. These complexes were characterized using IR, multinuclear (1H, 13C, 31P, 119Sn) NMR spectroscopy, elemental analysis, and in one case by single crystal X-ray diffraction. The NMR data show that the bisphosphonate ligands are coordinated to the tin center in a bidentate fashion forming cis octahedral tin complexes. Furthermore, the X-ray structure of complex 2b reveals that the bisphosphonate ligand is coordinated in a bidentate manner to the metal center in a distorted octahedral arrangement with Sn-O-P bond angles in the range 135.95(16)–137.99(18)°. The P = O and Sn-O bond lengths of 1.495(3)-1.497(3) and 2.134(3)-2.146(2) A, respectively are in the order expected for phosphonate tin(IV) complexes. The results are discussed and compared with closely related analogues.

Structural Control of Nonnative Ligand Binding in Engineered Mutants of Phosphoenolpyruvate Carboxykinase.

Protein engineering to alter recognition underlying ligand binding and activity has enormous potential. Here, ligand binding for Escherichia coli phosphoenolpyruvate carboxykinase (PEPCK), which converts oxaloacetate into CO2 and phosphoenolpyruvate as the first committed step in gluconeogenesis, was engineered to accommodate alternative ligands as an exemplary system with structural information. From our identification of bicarbonate binding in the PEPCK active site at the supposed CO2 binding site, we probed binding of nonnative ligands with three oxygen atoms arranged to resemble the bicarbonate geometry. Crystal structures of PEPCK and point mutants with bound nonnative ligands thiosulfate and methanesulfonate along with strained ATP and reoriented oxaloacetate intermediates and unexpected bicarbonate were determined and analyzed. The mutations successfully altered the bound ligand position and orientation and its specificity: mutated PEPCKs bound either thiosulfate or methanesulfonate but never both. Computational calculations predicted a methanesulfonate binding mutant and revealed that release of the active site ordered solvent exerts a strong influence on ligand binding. Besides nonnative ligand binding, one mutant altered the Mn2+ coordination sphere: instead of the canonical octahedral ligand arrangement, the mutant in question had an only five-coordinate arrangement. From this work, critical features of ligand binding, position, and metal ion cofactor geometry required for all downstream events can be engineered with small numbers of mutations to provide insights into fundamental underpinnings of protein-ligand recognition. Through structural and computational knowledge, the combination of designed and random mutations aids in the robust design of predetermined changes to ligand binding and activity to engineer protein function.

Structural characterisation and thermal stability of SnSe\\GaSb stacked films

ABSTRACTWe have investigated the effect of thermal annealing on the structure of single and stacked phase change memory films based on SnSe and GaSb. Samples were prepared by pulsed laser deposition and investigated by X-ray absorption spectroscopy (XAS) and X-ray diffraction (XRD) methods. Electrical resistance versus temperature investigations showed crystallisation temperatures of 292°C and 198°C for SnSe and GaSb single films, respectively. Above the transition temperature, GaSb crystallises into a face-centered cubic structure, whereas SnSe has an orthorhombic arrangement. Annealing at three temperatures (160°C, 250°C and 350°C) of the SnSe\\GaSb stacked films promotes bond breaking, atom diffusion between the two layers and formation of new phases. At 160°C, GaSb films crystallise partially and no effect is observed on the crystallinity of SnSe films. After 250°C, rhombohedral SnSb emerges in addition to GaSb complete crystallisation. A major, completely new, body-centered orthorhombic unindexed quaternary Ga-Sn-Sb-Se phase formation was observed in the samples annealed at 350°C. The GaSb crystallites are fully dissolved and we have observed the formation of a minor hexagonal SnSe2 phase. The analysis of EXAFS data, measured at Se and Ga K-edges, revealed changes in the local atomic environment as a function of the annealing temperature. A tetrahedral configuration is obtained for the Ga atoms in both as-deposited and annealed samples, whereas Se is mostly bivalent in the amorphous samples and has an octahedral arrangement in crystalline SnSe. Our results show that inter-layer diffusion should always be considered and evaluated when designing memory cells composed of stacked phase change chalcogenide films.

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear, Triangular, Tetragonal Pyramid, Trigonal Bipyramid, and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)6]·(NO3)2 (1), [Cu(L)4(H2O)]·(NO3)2·(H2O)5 (2), [Zn(L)4(H2O)]·(NO3)2·(H2O) (3), and [Ag2(L)4]·SO4 (4). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H···O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The NiII atom shows octahedral arrangement in 1, featuring a 3D twofold inclined interpenetrated network through O–H···O hydrogen bond and π–π stacking interaction. The CuII atom of 2 displays square pyramidal environment. The O–H···O hydrogen bond from the [Cu(L)4(H2O)]2+ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO3– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which ZnII has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The AgI in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO42– anions.

Interaction of polyelectrolyte complex between sodium alginate and chitosan dimers with a single glyphosate molecule: A DFT and NBO study

The formation of a polyelectrolyte complex through dimers of alginate and chitosan in the presence of sodium cations (SA/CS), and its interaction with the glyphosate herbicide, has been investigated at the DFT level (B3LYP/6‒311+G(d,p)). The lowest energy structure for SA/CS presents one Na+ cation coordinated to both dimers and formation of two H-bonds involving COO– and NH3+. The coordination energy of Na+ contributes with about 40% of the total complex stabilization energy. LMOEDA method indicates important contribution of covalent nature to stabilization of SA/CS. This result is corroborated by NBO analysis which shows high contribution of lp(O)→σ*(NH) overlapping, with average energy of 30 kcal mol−1 for the formed H-bonds. Two water molecules neighboring the complex increases its stability and promotes an octahedral coordination arrangement around Na+. The glyphosate interacts with SA/CS coordinating to Na+ and bonding to the chitosan dimer by H–bond, in agreement to performed fluorescence microscopy measurements.

Directed synthesis and magnetic properties of a hexanuclear ferric cluster

The hexanuclear iron(III) complex, [Fe6(µ3-3-bpp)4(µ3-O)2(µ2-OMe)3.67(µ2-OH)0.33Cl2]·0.33MeOH·H2O (1) was synthesized by a redox reaction between FeCl2, AgNO2, and 3-H2bpp in methanol (3-H2bpp = 2,6-bis(3-pyrazolyl)pyridine). The crystal structure of the complex is composed of two trinuclear subunits related by an inversion operation. This symmetry results in an overall octahedral arrangement of Fe(III) sites within the cluster. The four equatorial Fe sites are linked together by µ2-OMe− and µ2-OH− bridges, while each of the four 3-bpp2− bridges spans two axial and one equatorial Fe sites. The two Cl− ligands cap the axial Fe sites. The difference in the coordination environment for the equatorial and axial Fe sites is validated by the observation of two quadrupole doublets in the Mössbauer spectrum of 1, which also confirms that all metal sites correspond to the high-spin Fe(III) ions. Temperature-dependent magnetic susceptibility data reveal strong antiferromagnetic exchange coupling between the Fe(III) centers, which is also justified by quantum-chemical calculations at the density-functional level of theory.

Controlling Structure and Reactivity in Cationic Solid-State Molecular Organometallic Systems Using Anion Templating

The role that the supporting anion has on the stability, structure, and catalytic performance, in solid-state molecular organometallic systems (SMOM) based upon [Rh(Cy2PCH2CH2PCy2)(η2η2-NBD)][BArX4], [1-NBD][BArX4], is reported (X = Cl, F, H; NBD = norbornadiene). The tetra-aryl borate anion is systematically varied at the 3,5-position, ArX= 3,5-X2C6H3, and the stability and structure in the solid-state compared with the previously reported [1-NBD][BArCF34] complex. Single-crystal X-ray crystallography shows that the three complexes have different packing motifs, in which the cation sits on the shared face of two parallelepipeds for [1-NBD][BArCl4], is surrounded by eight anions in a gyrobifastigium arrangement for [1-NBD][BArF4], or the six anions show an octahedral cage arrangement in [1-NBD][BArH4], similar to that of [1-NBD][BArCF34]. C–X···X–C contacts, commonly encountered in crystal-engineering, are suggested to be important in determining structure. Addition of H2 in a solid/gas reaction affords the resulting σ-alkane complexes, [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArX4] [1-NBA][BArX4] (NBA = norbornane), which can then proceed to lose the alkane and form the zwitterionic, anion-coordinated, complexes. The relative rates at which hydrogenation and then decomposition of σ-alkane complexes proceed are shown to be anion dependent. [BArCF34]– promotes fast hydrogenation and an indefinitely stable σ-alkane complex. With [BArH4]– hydrogenation is slow and the σ-alkane complex so unstable it is not observed. [BArCl4]– and [BArF4]– promote intermediate reactivity profiles, and for [BArCl4]–, a single-crystal to single-crystal hydrogenation results in [1-NBA][BArCl4]. The molecular structure derived from X-ray diffraction reveals a σ-alkane complex in which the NBA fragment is bound through two exo Rh···H–C interactions-different from the endo selective binding observed with [1-NBA][BArCF34]. Periodic DFT calculations demonstrate that this selectivity is driven by the microenvironment dictated by the surrounding anions. [1-NBA][BArX4] are catalysts for gas/solid 1-butene isomerization (298 K, 1 atm), and their activity can be directly correlated to the stability of the σ-alkane complex compared to the anion-coordinated decomposition products.

Synthesis, characterization, biological activity, and QSAR studies of transition metal complexes derived from piperonylamine Schiff bases

A series of transition metal complexes of Co(II), Ni(II), Cu(II), and Zn(II) metal ions with various uninegative bidentate Schiff base ligands derived from condensation of piperonylamine and 2-hydroxy-1-naphthaldehyde/substituted salicylaldehyde derivatives were synthesized and were well characterized by different spectroscopic techniques (FT-IR, UV–Vis, NMR, fluorescence, mass, and ESR), molar conductance measurements, elemental analysis and by various physical studies like thermal (TGA, DTG, and DTA) and magnetic susceptibility measurements. The characterization data revealed that Schiff bases’ coordinates via azomethine nitrogen and deprotonated phenolic oxygen (NO) with metal centres in 2:1 molar ratio with octahedral geometrical arrangement for Co(II), Ni(II), and Zn(II) complexes and square planar geometry for Cu(II) complexes. The synthesized compounds were evaluated for their in vitro antimicrobial activities against two Gram-positive bacteria (Staphylococcus aureus and Streptococcus gordonii); two Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa); and two fungal strains (Aspergillus niger and Candida albicans). Comparative biological study indicated that metal complexes were more noxious as compared to free ligands and Zn(II) complexes were found to be most potent antimicrobial agents among all the synthesized complexes. The complexes 23–30 showed excellent activity against tested microorganisms. Quantitative structure–activity relationship study of compounds was made for antimicrobial assessment which exposed that metal complexes with high molecular weight were more potent against E coli.

Synthesis, characterization, molecular structures and anticancer activity studies 2-furan-2-ylmethyleneamino-phenyl-iminomethylphenolcomplexes

Objectives: To synthesize 2-furan-2-ylmethyleneamino-phenyl-iminomethylphenoland its complexes and evaluate the anticancer activity of the ligand and complexes against breast cancer cells. Methods/Statistical Analysis: A novel compounds have been synthesized and characterized by many spectral and DFT measurements. The molecular structural parameters of the synthesized furan-Schiff base ligand HL ligand and its isolated metal(II) complexes have been calculated. Anticancer activity for the ligand and the complexes were evaluated against breast cancer cells by using MTT assay. Findings: The microanalytical data of the isolated compounds are in good agreement with the calculated values and the spectroscopic analysis of the isolated complexes indicated that the HL ligand coordinated to the metal centers as tetra dentate ligand and form octahedral arrangement around metal(II) centers. The molecular parameters of the ligand and its metal complexes have been calculated and correlated with the experimental data such as IR and TGA results. The results of cells MCF7 breast cancer revealed of cell proliferation was much more highly inhibited by the HL ligand and its isolated complexes Co(II), Ni(II), Cu(II) and Zn(II) with cell viability 24.82, 58.9, 62.7, 73.8 and 87.3%, respectively at a concentration of 1000 PPM compared to untreated control cells. Application/Improvements: Lastly, some suggestions were presented to use these isolated compounds in vivo should be assessed to obtain worthy anticancer drugs. Keywords: Anticancer Activity, Characterization, Isolated Complexes, Molecular Structures, IR, TGA

Chiral Recognition of Racemic Proline based on Chiral Macrocyclic Nickel(II) Complex: Synthesis and Crystal Structures

The reactions of dl‐proline with chiral macrocyclic NiII complex [Ni(SS‐L)](ClO4)2 in acetonitrile/water gave a six‐coordinate enantiomer formulated as [Ni(SS‐L)(l‐Pro)](ClO4)2·H2O (1). Another enantiomer of [Ni(RR‐L)(d‐Pro)](ClO4)2·H2O (2) was obtained when [Ni(RR‐L)](ClO4)2 was used (L = 5,5,7,12,12,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane, Pro = proline). Single‐crystal X‐ray diffraction analyses of complexes 1 and 2 revealed that the NiII atom has a distorted octahedral coordination arrangement, being coordinated by four nitrogen atoms of L in a folded configuration, plus two carboxylate oxygen atoms of proline in mutually cis positions. Complexes 1 and 2 are supramolecular stereoisomers, which are constructed with hydrogen bonding linking of [Ni(SS‐L)(l‐Pro)]2+ and [Ni(RR‐L)(d‐Pro)]2+ monomers to form one‐dimensional zigzag chains. The homochiral natures of complexes 1 and 2 were confirmed by solid CD spectroscopy.