Oxygen Atoms Of Ligand Research Articles

Synthesis, Optoelectronic and Photoluminescent Characterizations of Green Luminous Heteroleptic Ternary Terbium Complexes

This article presents four ternary terbium complexes based on fluorinated 2-thenoyltrifluoroacetone (TTFA) and N donor bidentate neutral ligands. The prepared complexes were examined by elemental study, electrochemical analysis, spectroscopically and thermo-gravimetrically. Spectral analysis shows the bonding of Tb3+ ion with oxygen and nitrogen atom of diketone and neutral ligand respectively. Upon excitation in UV region, synthesized terbium complexes show luminescence in green region of electromagnetic spectrum. Photoluminescence emission spectra of complexes do not show any ligand based peak suggesting the effective transferal of energy from ligand to metal ion. Green emanation by terbium complexes is owing to intense peak ~547nm (5D4 → 7F5). The outcome of emission data and CIE coordinates correlate with each other and affirms the utility of green luminous complexes as potential emissive material for optoelectronic gadgets applied in lighting system.

Synthesis, characterization and exploration of supramolecular interactions of a Cu(II) based 1D zig-zag coordination polymer: X-ray structure determination and DFT study

A novel Cu(II) based one-dimensional (1D) zig-zag coordination polymer (CP) formulated as [Cu(muco)(4,4′-Me2bpy)(H2O)]·2H2O (1; H2muco = trans, trans-1,3-butadiene-1,4-dicarboxylic acid or trans, trans-muconic acid and 4,4′-Me2bpy = 4,4′-dimethyl-2,2′-bipyridine) was synthesized in a self-assembly reaction using slow evaporation technique. Single crystal X-ray analysis reveals that the compound 1 crystallizes in the triclinic system, space group Pī witha = 9.7436(12) Å,b = 11.1836(14) Å,c = 11.5063(14) Å; α = 61.520(1)°, β = 85.019(1)°, γ = 66.864(1)° and V = 1005.6(2) Å3. Its structure is composed of Cu(II) centres with a distorted square pyramidal configuration interconnected by muco ligand in an array to generate zig-zag chain. A three- dimensional (3D) supramolecular network is formed among 1D chains of 1 via hydrogen bonding and π··π interactions. Interestingly, the connectivity of lattice water molecules shows a water dimer cluster, which further undergoes hydrogen bonding along with coordinated water molecules and oxygen atoms of muco ligands to generate an octameric cluster with chair-like hexameric unit. The excellent coordinating characteristics of muco and bipyridine ligands owing to non-covalent interactions to stabilize compound1have been investigated by means of Hirshfeld analysis. The density functional theory (DFT) study is performed to calculate the HOMO-LUMO gap which enlightens the possible future application of 1 as a semiconducting device. The theoretical findings are also validated experimentally by band gap calculation utilising Tauc’s plot exploring the UV data.

Preparation, Characterization of Some Metal Complexes of New Mixed Ligands Derived from 5-Methyl Imidazole and Study the Biological Activity of Palladium (II) Complex as Anticance

A new series of mixed ligand complexes synthesized and characterized using of azo ligand derived from (5-methyl— imidazole) with (8-hydroxy quinolone). New mix-ligand structures and their transitional metal complexes were fully characterized using several techniques, including molar conductance, elemental analysis (C.H.N), electronic spectral, magnetic measurements, 1HNMR, spectral studies, and mass spectra. The data shows that these complexes have a composition of [ML(8-HQ) Cl2] H2O where M = Co(II), Zn(II), Cu(II), X=0, and Ni(II), X=1, [ML(8-HQ)] Cl. where M=Pd. The electronic spectral data and magnetic susceptibility calculations of the complexes indicate that the octahedral geometry of all complexes, except for the Pd(II) complex, indicates a planar-square geometry. The results demonstrate that the nitrogen of the imidazole ring and azo nitrogen atom of the primary ligand are coordination sites with a nitrogen atom and oxygen atom of a secondary ligand of the (8-HQ) in the basic medium. Biological effects of the palladium (II) complex are screening against human breast cancer (MCF-7 and AMJ-13) and normal cells (HBL) were examined, which indicated colon cancer cell line LS-174. The results show the highest activity effect for the complex.

Synthesis and structural characterization of three new mixed ligand alkaline-earth metal picrates

Abstract The dissolution of alkaline-earth metal carbonate in aqueous picric acid followed by reaction with nicotinamide results in the formation of [M(H2O) n (nic)2(pic)2] (nic = nicotinamide; pic = picrate; n = 1 and M = Ba 1; n = 2 and M = Ca (or Sr) 2 (or 3)). In [Ba(H2O)(nic)2(pic)2] 1, the barium and the oxygen atoms of a terminal aqua ligand are located on a two-fold axis. Compound 1 exhibits a {BaO7N2} coordination sphere, where the barium atom is bonded to a unique bidentate picrate and the crystallographically independent nicotinamide bridges to two symmetry related barium atoms with a Ba···Ba separation of 9.799 Å via the pyridine nitrogen and the amide oxygen atoms leading to the formation of a two-dimensional coordination polymer. The compounds 2 and 3 are isostructural with discrete molecules. The central Ca atom in 2 (or Sr in 3) located on a two-fold axis is bonded to a crystallographically unique terminal aqua ligand, an independent monodentate nicotinamide and a unique bidentate picrate anion resulting in a distorted {MO8} polyhedron. The mixed ligand alkaline-earth metal picrates 1–3 exhibit three varieties of hydrogen bonding and π–π stacking interactions. Several alkaline-earth metal picrates are compared in this study.

Окисление трис(2-метокси-5-бромфенил)сурьмы трет-бутилгидропероксидом в присутствии соединений, содержащих подвижный атом водорода

Oxidation of tris(2-methoxy-5-bromophenyl)antimony with tertiary butylhydroperoxide in the presence of water, benzoic acid, 2,6-dihydroxybenzoic acid and 2-chloro-4-fluorophenol in diethyl ether leads to formation of tris(2-methoxy-5-bromophenyl)antimony oxide (1), tris(2-methoxy-5-bromophenyl)antimony dibenzoate (2), -oxo[hexakis(2-methoxy-5-bromophenyl)-bis(2,6-dihydroxybenzoato)diantimony] (3), -oxo[hexakis(2-methoxy-5-bromophenyl)-bis(2-chloro-4-fluorophenoxo)diantimony] (4), respectively. The compounds have been identified by X-ray diffraction analysis. According to the X-ray diffraction data, the crystal of solvate 1 with chloroform consists of centrosymmetric binuclear molecules containing the Sb2O2 cycle with tetragonal coordination of the antimony atoms (the Sb–O bond lengths are 1.961(4) and 2.041(5) Å, the Sb–C distances are 2.114(6)–2.153(6) Å). In solvate 2 with benzene the antimony atoms have a distorted trigonal-bipyramidal coordination with the oxygen atoms of carboxylate ligands in axial positions (Sb–O 2.075(4), 2.105(4) Å), the carbonyl oxygen atoms are coordinated with the central metal atom (Sb∙∙∙O=C 3.023(6), 3.077(8) Å), the Sb–C bond lengths (2.104(5)–2.112(5) Å) are significantly less than in 1. The ranges of variation in the Sb–C bond lengths in the practically linear binuclear molecule of solvate 3 with acetonitrile are 2.101(5)–2.106(5) and 2.100(5)–2.104(5) Å (the SbOSb angle equals 178.05(18)). The bond lengths of antimony atoms with the bridging oxygen atom (1.925(4), 1.936(4) Å) are less than the sum of the covalent radii of antimony and oxygen, as well as the distances between the antimony atom and the terminal carboxyl ligand (Sb–O 2.263(4), 2.214(4) Å). The carbonyl oxygen atoms are coordinated with the central metal atom (Sb∙∙∙O=C 3.484(8), 3.512(9) Å) to a lesser extent than in 2. The crystal of solvate 4 with benzene contains two types of crystallographically independent corner molecules (the SbOSb angles are 163.75(18), 164.27(19)), the difference in lengths of the Sb–Obridge (1.939(11)–1.981(13) Å) and Sb–Oterm (2.096(11)–2.208(11) Å) is not as sharp as in the case of complex 3. Complete tables of atom coordinates, bond lengths and valence angles are deposited at the Cambridge Crystallographic Data Center (No. 2070383 (1); No. 2074511 (2); No. 1970910 (3); No. 2064392 (4); deposit@ccdc.cam.ac.uk or http://www.ccdc.cam.ac.uk/data_request/cif).

Synthesis, spectral characterization, crystal structures, biological activities, theoretical calculations and substitution effect of salicylidene ligand on the nature of mono and dinuclear Zn(II) Schiff base complexes

Two new zinc(II) Schiff base complexes (Z1 and Z2) are prepared by treating ONNO tetradentate Schiff base ligands (H2L1 = [6,6′-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol)] and H2L2 = [2,2′-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azanylylidene))bis(methanylylidene))bis(4-methoxyphenol)]) with acetylacetonate salt of zinc. The synthesized Schiff base ligands and their respective zinc(II) complexes were characterized by elemental analysis (CHN) and various spectroscopic techniques like FT-IR and 1H NMR. The single crystal X-ray structures of Z1 and Z2 show the effect of salicylidene ligand on the nature of mono and dinuclear Zn(II) Schiff base complexes. In Z1 complex, a square pyramidal geometry is adapted by the complex, supported by the ONNO donor atoms of the tetradentate Schiff base and a coordinated water molecule. Structural analysis of Z2 complex revealed that the compound is a centrosymmetric dimer in which the five coordinated Zn(II) atoms are linked to the opposite metal center by making μ-phenoxo bridges through one of the phenolic oxygen atoms of Schiff base ligands. The nature of various kinds of non-covalent interactions present among the sample molecules was also investigated by using QTAIM and NCI calculations. The theoretical calculations were performed by DFT using the B3LYP/Def2-TZVP level of theory, which indicated that the intended outcomes are in compliance with the actual consequences. Furthermore, the antibacterial potential of the Schiff base ligands and their corresponding zinc complexes was measured by testing them against two Gram-positive (Staphylococcus aureus and Bacillus cereus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacterial strains. The agar well diffusion method and poisoned media technique were used for screening of bacterial and fungal species, respectively. According to the results of the zone of inhibition assessments, metal complexes have comparatively more inhibition potential relative to free ligands.

Structural investigations, Hirsfeld surface analyses, and molecular docking studies of a phenoxo-bridged binuclear Zinc(II) complex

A novel phenoxo-bridged zinc complex, [Zn2(L)µ(O-O)2H2OCl2] [L= deprotonated salen ligand, 2,2′-((1E,1′E)-((2,2-dimethylpropane-1,3-diyl)bis(azaneylylidene))bis(methaneylylidene))diphenol), was reported. The title complex was characterized by elemental analyses, single crystal X-ray crystallography, spectroscopic studies, and thermogravimetric analysis. The X-ray structure analysis reveals the coordination of Zn1 atom to two imine nitrogen atoms, two phenolic oxygen atoms, and the oxygen atom of aqua ligand, giving it a distorted square pyramidal geometry, whereas the Zn2 atom is bonded to the same phenoxide anions, and two chloride ions, resulting in a distorted tetrahedral geometry. In addition, TD-DFT and NBO analyses were investigated to obtain bonding information insights into the structure. Furthermore, Hirshfeld surface analysis was used to determine various intermolecular interactions in the complex. Furthermore, a docking analysis was performed on the B-DNA [sequence d (CGCGAATTCGCG)2dodecamer] (PDB ID:1BNA) using the AutoDockvina (scripps) software package. The fluorescence property of the title complex was also carried out, and revealed it to be excellent photoluminescent material.

THE SYNTHESIS AND PROPERTIES OF A SODIUM SUPRAMOLECULAR CRYSTAL NETWORK CONSTRUCTED WITH FUNCTIONAL PYRAZINE SULFONIC ACID

Sulfonic acid groups with C3ν symmetry can coordinate with metal ions to produce multidimensional structures due to their flexible coordination modes. They can also penetrate into supramolecular structures through an intriguing bridging pattern and weak interactions. Herein, a novel heterocyclic sodium sulfonate supramolecular structure, namely [Na(Pyr-SO3)(H2O)]n where Pyr-SO3H is pyrazine sulfonic acid, is synthesized by utilizing NaBF4 to coordinate with the P–SO3H ligand through the solvent evaporation method. The single crystal X-ray diffraction (XRD) data indicate that the as-formed structure belongs to the Pbca space group. Additional properties are characterized by powder XRD, thermal analysis, and solid-state fluorescence. In particular, the introduction of a soft alkali metal ion can coordinate with the oxygen atom of the sulfonate ligand and form a Na–O bridging configuration that can not only significantly improve the pyrazine sulfonic acid ligand coordination ability, but also provide a reference for the extended study of functional sulfonate polymers in the future.Electronic supplementary materialSupplementary material is available for this article at 10.1134/S0022476621110172 and is accessible for authorized users.

Binuclear Zn(II) Schiff base complexes: Synthesis, spectral characterization, theoretical studies and antimicrobial investigations

Binuclear zinc(II) Schiff base complexes were synthesized through the reaction of ONNO tetradentate Schiff base ligands derived from the condensation of 2,2-dimethyl-1,3-propanediamine and 5-chlorosalicylaldehyde or 5-bromosalicylaldehyde with zinc acetylacetonate salt. The structures of synthesized products were explored spectroscopically through the FT-IR, 1H NMR and elemental analysis. Structural analysis of the complexes revealed that the compound is a centrosymmetric dimer in which the five coordinated Zn(II) atoms are linked to the opposite metal center by making μ-phenoxo bridges through one of the phenolic oxygen atoms of Schiff base ligands. The nature and types of non-covalent interactions present among the sample molecules were also investigated by using the quantum theory of atoms in molecules and non-covalent interactions calculations. The theoretical calculations, performed by density functional theory using the B3LYP/Def2-TZVP level of theory, direct that the intended outcomes are in compliance with the actual consequences. Furthermore, from antimicrobial screenings it was revealed that the zinc complexes are more active as compared to the ligands.

Zn(II) complexes containing O,N,N,O-donor Schiff base ligands: synthesis, crystal structures, spectral investigations, biological activities, theoretical calculations and substitution effect on structures

New zinc(II) Schiff base complexes (Z1 and Z2) were prepared through the treatment of ONNO tetradentate Schiff base ligands (H2L1 and H2L2 ) with zinc acetylacetonate. Elemental analysis (C, H and N) and other spectroscopic techniques such as FT-IR and 1H NMR were used to characterize the produced ligands and their associated Zn(II) complexes. The structure of Z1 was explored by single crystal X-ray diffraction analysis. The structural investigations of Z1 demonstrate that it exists in the form of a centrosymmetric dimer in which penta coordinated Zn(II) ions are inter connected via µ-phenoxo bridges from one of the phenolic oxygen atoms of each tetradentate Schiff base ligand to the opposite zinc(II) ions. The theoretical calculations, performed by DFT using the B3LYP/Def2-TZVP level of theory, directed that the intended outcomes are in compliance with the actual consequences. The nature and types of non-covalent interactions present among the sample molecules were also investigated by using QTAIM and NCI calculations. Furthermore, antimicrobial activities of the synthesized Schiff base ligands and their respective zinc(II) complexes were also examined against two Gram-positive (Staphylococcus aureus and Bacillus cereus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa) bacteria, and two fungal species (Aspergillus brasiliensis and Candida albicans). The agar well diffusion method and poisoned media technique were used for the study of biological properties of bacterial and fungi species, respectively. According to assessments of inhibitory zones, metal chelates are found to be somewhat more efficient than free ligands.

Geometrical variations of two manganese(II) complexes with closely related quinoline-based tripodal ligands.

Structural analyses of the compounds di-μ-acetato-κ4 O:O'-bis-{[2-meth-oxy-N,N-bis-(quinolin-2-ylmeth-yl)ethanamine-κ4 N,N',N'',O]manganese(II)} bis-(tetra-phen-yl-borate) di-chloro-methane 1.45-solvate, [Mn2(C23O2)2(C23H23N3O)2](C24H20B)·1.45CH2Cl2 or [Mn(DQMEA)(μ-OAc)2Mn(DQMEA)](BPh4)2·1.45CH2Cl2 or [1](BPh4)2·1.45CH2Cl2, and (acetato-κO)[2-hy-droxy-N,N-bis(quinolin-2-ylmeth-yl)ethanamine-κ4 N,N',N'',O](methanol-κO)manganese(II) tetra-phenyl-borate methanol monosolvate, [Mn(CH3COO)(C22H21N3O)(CH3OH)](C24H20B)·CH3OH or [Mn(DQEA)(OAc)(CH3OH)]BPh4·CH3OH or [2]BPh4·CH3OH, by single-crystal X-ray diffraction reveal distinct differences in the geometry of coordination of the tripodal DQEA and DQMEA ligands to MnII ions. In the asymmetric unit, compound [1](BPh4)2·(CH2Cl2)1.45 crystallizes as a dimer in which each manganese(II) center is coordinated by the central amine nitro-gen, the nitro-gen atom of each quinoline group, and the meth-oxy-oxygen of the tetra-dentate DQMEA ligand, and two bridging-acetate oxygen atoms. The symmetric MnII centers have a distorted, octa-hedral geometry in which the quinoline nitro-gen atoms are trans to each other resulting in co-planarity of the quinoline rings. For each MnII center, a coordinated acetate oxygen participates in C-H⋯O hydrogen-bonding inter-actions with the two quinolyl moieties, further stabilizing the trans structure. Within the crystal, weak π-π stacking inter-actions and inter-molecular cation-anion inter-actions stabilize the crystal packing. In the asymmetric unit, compound [2]BPh4·CH3OH crystallizes as a monomer in which the manganese(II) ion is coordinated to the central nitro-gen, the nitro-gen atom of each quinoline group, and the alcohol oxygen of the tetra-dentate DQEA ligand, an oxygen atom of OAc, and the oxygen atom of a methanol ligand. The geometry of the MnII center in [2]BPh4·CH3OH is also a distorted octa-hedron, but the quinoline nitro-gen atoms are cis to each other in this structure. Hydrogen bonding between the acetate oxygen atoms and hydroxyl (O-H⋯O) and quinolyl (C-H⋯O and N-H⋯O) moieties of the DQEA ligand stabilize the complex in this cis configuration. Within the crystal, dimerization of complexes occurs by the formation of a pair of inter-molecular O3-H3⋯O2 hydrogen bonds between the coordinated hydroxyl oxygen of the DQEA ligand of one complex and an acetate oxygen of another. Additional hydrogen-bonding and inter-molecular cation-anion inter-actions contribute to the crystal packing.

Synthesis and structure of a mixed ligand copper(II) compound based on a distorted {CuN2O3} square pyramid

The synthesis, spectra, thermal study and crystal structure of a mixed ligand copper(II) compound viz. [Cu(biq)(acac)(NO 3 )] 1 (biq = 2,2′-biquinoline, acac = acetylacetonate) are reported. The {CuN 2 O 3 } coordination sphere is made up of two oxygen atoms of an unique acac ligand, an oxygen of the nitrate group and one N atom of biq ligand which form the basal plane {CuNO 3 } of a square pyramid. A second nitrogen atom of the biq ligand occupies the apical position resulting in a distorted square pyramidal {CuN 2 O 3 } polyhedron. In the crystal structure, each neutral square pyramidal copper(II) species is linked with two symmetry related molecules with the aid of intermolecular C-H×××O hydrogen bonding interactions. A study of fifteen mixed ligand copper(II) acetylacetonates reveals that in this series of compounds, 1 exhibits maximum deviation of the {CuN 2 O 3 } polyhedron from square pyramidal towards trigonal bipyramidal geometry.

A Porous Copper-Organic Framework Assembled by [Cu12] Nanocages: Highly Efficient CO2 Capture and Chemical Fixation and Theoretical DFT Calculations.

A new porous copper-organic framework assembled from 12-nuclear [Cu12] nanocages {[Cu2(L4-)(H2O)2]·4DMA·2H2O}n (1) (H4L = 5,5'-(butane-1,4-diyl)-bis(oxy)-diisophthalic acid) was successfully prepared and structurally characterized. Compound 1 feathering of a 3D framework with two types of 1D nanotubular channels and a large specific surface area can effectively enrich various harmful dyes. Additionally, due to the carbon dioxide (CO2) interactions with open Cu(II) sites and the electron-rich ether oxygen atoms of ligand in 1, it exhibits a highly selective CO2 uptake. Interestingly, 1 can effectively catalyze the cycloaddition reaction of CO2 with various epoxides under mild conditions, which is ascribed to the Lewis acid Cu(II) sites in the framework of 1. Importantly, 1 acting as a heterogeneous catalyst can be recycled at least 10 times without an obvious loss of catalytic activity, and the CO2 cycloaddition mechanism was further uncovered by density functional theory (DFT) calculations. This study can greatly enrich the MOF catalysts system of CO2 conversion and also provide a valuable guidance for the design of efficient MOFs catalysts.

μ-Methyl-ene-bis-[di-bromido(diethyl ether-κO)aluminium(III)]: crystal structure and chemical exchange in solution.

In the title compound, [Al2Br4(CH2)(C4H10O)2], the mol-ecule lies on a crystallographic twofold axis passing through the bridging C atom. Each AlIII atom is four-coordinate, being bonded to two bromide ions, bridging the CH2 group as well as the oxygen atom of a diethyl ether ligand in a slightly distorted tetra-hedral arrangement with angles ranging from 101.52 (8) to 116.44 (5)°. The Al-CH2-Al angle, 118.4 (2)°, is the smallest observed for a structure where this moiety is not part of a ring. In the crystal, weak C-H⋯Br inter-actions, characterized as R 2 2(12) rings, link the mol-ecules into ribbons in the [101] direction. The title compound is monomeric and coordinatively saturated in the solid state, as each aluminum is four-coordinate, but in solution the ether mol-ecules from either or both Al atoms can dissociate, and would be expected to rapidly exchange, and this is supported by NMR data.

A series of lanthanide complexes with 2-fluorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine: Synthesis, supramolecular structures, spectroscopy and thermal behaviour

A family of lanthanide-based self-assembling complexes constructed from 2-fluorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine have been successfully fabricated via conventional synthesis, namely, [Ln(2-FBA)3(5,5′-DM-2,2′-bipy)]2 (2-FBA = 2-fluorobenzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′-bipyridine, Ln = La(1), Pr(2), Nd(3), Sm(4), Gd(5), Dy(6), Ho(7), Er(8)). The obtained complexes are investigated by means of elemental analysis, IR spectra, Raman spectra and single-crystal X-ray diffraction. Crystallographic results exhibit that each Ln3+ ion of them is located in a distorted Muffin coordination sphere finished by seven oxygen atoms of 2-FBA ligands and two nitrogen atoms of 5,5′-DM-2,2′-bipy ligand. Interestingly, although complexes 1–6 and 7–8 have the same formula unit, the differences in hydrogen bond interactions lead to different supramolecular structures. Besides, the thermal decomposition mechanism of the complexes has been studied by TG/DSC-FTIR technology. The results show that these complexes are thermally stable up to 450 K. In addition, complexes 4 and 6 both exhibit the characteristic fluorescence of lanthanide ions, that is, complex 4 exhibits characteristic 4G5/2→6HJ/2 (J = 5, 7, 9) transitions, and complex 6 shows characteristic 4F9/2→6HJ/2 (J = 15, 13) transitions.

Novel titanium(IV) diolate complexes with additional O‐donor as precatalyst for the synthesis of ultrahigh molecular weight polyethylene with reduced entanglement density: Influence of polymerization conditions and its implications on mechanical properties

New alkoxo‐titanium(IV) complexes with diolate ligand containing additional donor oxygen atom have been synthesized from readily available and scalable precursors. The structure of complex 4 was established by X‐ray diffraction. Titanium atom adopts a distorted tetrahedral geometry formed by six oxygen atoms of ligands. The resulting complexes 3–4 are moderately or highly active in ethylene polymerization in the presence of {EtnAlCl3–n + Bu2Mg} binary cocatalysts. The influence of the nature of the solvent, the organoaluminum cocatalyst and the polymerization temperature on the activity of catalytic systems, and the properties of the resulting polymers were studied. The obtained polymers are linear polyethylene of ultrahigh molecular weight (up to 5.8·106 g mol−1) with a broad molecular weight distribution. The polymers are suitable for the modern methods of polymer processing—the solventless solid‐state formation of super high‐strength (breaking strength up to 2.8 GPa) and high‐modulus (elastic modulus up to 140 GPa) oriented films and film tapes. The possibility of scaling up the synthesis of ultrahigh molecular weight polyethylene (UHMWPE) without a significant drop in the productivity of the catalytic system and polymer properties is shown. UHMWPE samples have been investigated by small‐angle X‐ray scattering (SAXS) methods to study the structural changes induced by solid‐state drawing of nascent reactor powders.

Zinc(II) and cadmium(II) coordination polymers with bis(4-pyridyl)benzylamine: structure and photoluminescence

Two coordination polymers, [(bpba)Zn(CH3COO)2]n (1) and [(bpba)3Cd2(NO3)4]n·nMeOH·4nH2O (2) (bpba = bis(4-pyridyl)benzylamine), were obtained using Zn(CH3COO)2·2H2O/Cd(NO3)2·4H2O and bpba in a mixture of solvents, and were further characterized. The zinc(II) ion of 1 showed a tetrahedral geometry with two oxygen atoms of the acetate ligands and two pyridine groups of the bpba ligands, and it is linked to the neighboring zinc(II) ions through the bpba ligands, giving rise to an interesting one-dimensional helical structure. Contrastingly, the cadmium(II) ion of polymer 2 was bonded by three pyridine groups of three different bpba ligands and four oxygen atoms of two nitrate ligands, exhibiting a T-shaped geometry. Thus, polymer 2 forms a two-dimensional wave-like structure by the coordination of cadmium(II) ion and bpba ligand to each other. Polymers 1 and 2 showed strong UV emissions depending on the metal ions and are red-shifted, compared to the bpba ligand.

Zinc(II) niflumato complex with neocuproine: Synthesis, crystal structure, characterization and cytotoxic effects on human endometrial cell lines

Novel zinc niflumato complex with a composition of [Zn(neo)(nif)2] (neo = neocuproine; nif = niflumato) was prepared in crystalline form and characterized by elemental analysis and spectroscopic methods (IR, UV/VIS and fluorescence). According to the results of the single-crystal X-ray structural analysis the central Zn(II) atoms within the complex molecules are tetracoordinated by two oxygen atoms of nif ligands and two nitrogen atoms of chelate bonded neo. The cytotoxic measurements on two endometrial cell lines hTERT and 12Z indicate selectivity of the complex towards the endometriotic 12Z cell line. In addition, spectral binding studies performed on isolated DNA samples revealed higher affinity of the complex to the 12Z DNA, thus suggesting possible specific DNA sequence recognition.

The guanidinium t-diaqua-bis(oxalato)chromate(III) dihydrate complex: synthesis, crystal structure, EPR spectroscopy and magnetic properties

Abstract A new salt (CH6N3)[t-Cr(C2O4)2(H2O)2]·2H2O (1) (CH6N3 + = guanidinium cation) has been synthesized and characterized by single-crystal X-ray diffraction, FT-IR and UV–Vis spectroscopies, elemental and thermogravimetric analyses. In the crystal structure of 1, the chromate(III) ion lies on an inversion center in the form of an elongated octahedron. The coordination sphere consists of four oxygen atoms of two chelating oxalato ligands in the equatorial plane and two axial oxygen atoms of water ligands. The structural feature of focal interest in the structure of 1 is the formation of pillars of [Cr(C2O4)2(H2O)2]− complex anions and CH6N3 + guanidinium cations, with the next-neighbor cations rotated by an angle of 60° relative to each other. O–H···O and N–H···O hydrogen bonds play an important role in the construction of the three-dimensional network. The electron paramagnetic resonance (EPR) and magnetic properties of 1 have also been investigated.

Solid-Phase Quasi-Intramolecular Redox Reaction of [Ag(NH3)2]MnO4: An Easy Way to Prepare Pure AgMnO2.

Two monoclinic polymorphs of [Ag(NH3)2]MnO4 containing a unique coordination mode of permanganate ions were prepared, and the high-temperature polymorph was used as a precursor to synthesize pure AgMnO2. The hydrogen bonds between the permanganate ions and the hydrogen atoms of ammonia were detected by IR spectroscopy and single-crystal X-ray diffraction. Under thermal decomposition, these hydrogen bonds induced a solid-phase quasi-intramolecular redox reaction between the [Ag(NH3)2]+ cation and MnO4– anion even before losing the ammonia ligand or permanganate oxygen atom. The polymorphs decomposed into finely dispersed elementary silver, amorphous MnOx compounds, and H2O, N2 and NO gases. Annealing the primary decomposition product at 573 K, the metallic silver reacted with the manganese oxides and resulted in the formation of amorphous silver manganese oxides, which started to crystallize only at 773 K and completely transformed into AgMnO2 at 873 K.