Showing papers in "Russian Journal of Coordination Chemistry in 2010"

Magnetic exchange in Bi- and polynuclear complexes of transition metals with hydrazones and azomethines

Abstract: Magnetic exchange data for bi- and polynuclear complexes of transition metals with hydrazones, Schiff bases, oximes, and related systems were generalized and systematized. A correlation between the electronic and geometrical structures of the complexes and characteristic exchange effects was discussed. A systematic analysis of magnetostructural correlations in such complexes was performed.

Electrochemical transformations of catecholate and o-amidophenolate complexes with triphenylantimony(V)

Abstract: The electrochemical properties of catecholate and o-amidophenolate complexes with triphenylantimony(V) with various substituents in the aromatic ring were examined. Introduction of electron-donating groups into the catecholate ligand or replacement of an O atom (in catecholate) by a N atom (o-amidophenolate) stabilizes the monocationic forms of the complexes obtained by one-electron oxidation. Complexes with electron-withdrawing substituents undergo irreversible two-electron oxidation resulting in the elimination of o-quinone. Complexes containing electron-withdrawing ligands do not form o-semiquinones and are inert to atmospheric oxygen. According to electrochemical data, oxygen can be bound reversibly by catecholate complexes containing the electron-donating methoxy groups in the 3,6-di-tert-butylcatecholate ligand and o-amidophenolate derivatives with half-wave oxidation potentials lower than or equal to 0.70 V (vs. Ag/AgCl), which form relatively stable cationic complexes upon the oxidation.

Spin crossover in iron(II) complexes with tris(pyrazol-1-yl)methane

Abstract: Mononuclear iron(II) coordination compounds with tris(pyrazol-1-yl)methane (HC(Pz)3) described as [Fe{HC(Pz)3}2]A2 × nH2O, where A = Cl−, Br−, I−, 1/2 SO42−, n = 0–7, were synthesized. The compounds were studied by static magnetic susceptibility measurements, IR and UV/Vis spectroscopy, and powder X-ray diffraction. The crystal and molecular structures of all compounds were determined by single crystal X-ray diffraction.

Synthesis, characterization, crystal structure, and biological activity of the copper complex

Abstract: This work reports the synthesis and biological activity of the copper complex with 2–thenoyltrif-luoroacetone (HTTA). The complex was characterized by elemental analysis, infrared spectroscopy, and thermogravimetric analysis. The crystal structure was determined by single-crystal X-ray diffraction. The complex exists as a parallelogram with four coordination sites occupied by the carbonyl oxygen atoms from HTTA. The antibacterial activity test shows that the complex exhibits better antibacterial ability against Escherichia coli and Staphylociccus aureus (MIC were about 180, 150 μg/ml, respectively) and can be considered as broad-spectral antimicrobial. The antitumor activity of the copper(II) complex is tested by methyl thiazolyl tetrazolium assays against human Leukemia cells K562. The copper(II) complex exhibits potent antitumor effects against K562 cell lines. The IC50 value of the complex is about 0.01 μg/ml. The research shows that the complex can inhibit K562 tumor cell growth and generation and induce apoptosis. The inhibition ratio is accele by increasing the dosage and has a significant positive correlation with medication dosage.

Stabilization of silicon nanoparticles by carbenes

Abstract: Sodium reduction of a mixture of tetrabromosilane with imidazole ionic liquids in organic solvents gives dispersions of silicon nanoparticles stabilized by carbene ligands. It was shown that the size of silicon nanoclusters depends on the size of substituents at nitrogen atoms of 1,3-dialkylimidazol-2-ylidenes.

Molecular design of azomethine complexes

Abstract: Data on the coordination chemistry of azomethines, which are based on the molecular design concept formulated and developed by V.I. Minkin and his disciples, are generalized and systematized. Particular attention is given to the methods for targeted synthesis of five- and/or six-membered chelates containing chalcogen atoms (S, Se, and Te) and nonstandard (heteroleptic, molecular, and supramolecular) structures. Achievements in the design of magnetically active and luminescent complexes and azomethine complex additives to lubricants are discussed.

Synthesis, characterization, and crystal structures of two Schiff base zinc(II) complexes with urease inhibitory activities

Abstract: Two Schiff base zinc(II) complexes, [ZnBr2L1] · 2CH3OH (I) (I) and [ZnBr2L2] (II), where L1 is 4-chloro-2-[(2-piperazin-1-ylethylimino)methyl]phenol and L2 is 4-chloro-2-[(3-diethylaminopropylimino)methyl]phenol were synthesized and structurally characterized. The crystal of I is monoclinic: space group P21/c, a = 9.831(3), b = 18.680(6), c = 11.879(4) A, β = 94.660(6)°, V = 2174.3(11) A3, Z = 4. The crystal of II is monoclinic: space group P21/n, a = 7.2310(14), b = 16.037(3), c = 15.856(3), β = 90.01(3)°, V = 1838.7(6) A3, Z = 4. The Zn atom in each complex is four-coordinated by one phenolate O and one imine N atoms of the Schiff base ligand and two bromide atoms, forming a tetrahedral coordination. The urease inhibitory activities of the complexes were evaluated.

Metal complexes with azomethines containing the isomeric E-Z azo fragments

Abstract: Cobalt and zinc complexes with phenylazosalicylaldehyde azomethines were obtained by chemical and electrochemical syntheses. The B3LYP/6-311G(d, p) calculations showed that the azo group in both the ligands and the complexes are mainly in the E-form.

Formation of the heteropolynuclear complex ([NH2(C4H9)2][Au{S2CN(C4H9)2}2][CdCl4]) n during the chemisorption of gold(III) with cadmium dibutyldithiocarbamate: Structure and thermal properties

Abstract: The chemisorption properties of cadmium dibutyldithiocarbamate with respect to [AuCl4]− in 2M HCl solutions are studied. The heterogeneous reaction of gold(III) binding affords the heteropolynuclear compound ([NH{2(C4H9)2][Au{S2CN(C4H9)2}2][CdCl4])n (I). The molecular and crystal structures of compound I are determined from the X-ray diffraction data. Each of three ions is presented in the structure by two conformers. The irreversible decomposition of some dibutyldithiocarbamate groups is observed during the chemisorption of gold(III), which noticeably decreases the efficiency of gold binding with the sorbent studied and its sorption capacity. The study of the thermal properties of compound I shows that gold(III) is reduced to the metal during thermolysis.

Synthesis, physicochemical, antimicrobial, and 3D molecular modeling studies of oxomolybdenym(V) and dioxomolybdenum(VI) complexes with a Schiff base isonicotinoyl(5-bromo-2-hydroxybenzylidene)hydrazide

Abstract: Synthesis of some new oxomolybdenum(V) and dioxomolybdenum(VI) complexes with a Schiff base isonicotinioyl(5-bromo-2-hydroxybenzylidene)hydrazide (L) derived from 5-bromosalicylaldehyde and isonicotinoylhydrazide are reported. The complexes have been characterized by elemental analyses, molar conductance, magnetic susceptibility data, IR, UV-Vis, EPR, 1H NMR, and FAB mass spectral studies. The physicochemical studies and spectral data indicate that L acts as a monovalent tridentate chelating agent. The FAB mass and X-band EPR spectra indicate that the pentavalent Mo in the complex is monomeric in nature. The X-ray diffraction studies of the complex [MoO(L)Cl2] (I) correspond to the orthorhombic crystal lattice with the unit cell dimensions a = 16.11, b = 12.20, and c = 7.5 A. The electrochemical behavior of the complex was investigated by cyclic voltammetry. All the complexes are found to be neutral with the distorted octahedral geometry. The thermal properties of the complex I were investigated by thermogravimetric techniques. The ligand L and the complexes I and [MoO2(L)Cl] (II) were screened for their in vitro antimicrobial activity. The complexes exhibited higher activity than L. The 3D molecular modeling and analysis for bond length and bond angles have also been carried out for complex I.

Coordination of gold(III) in the chemisorption by cadmium diisobutyldithiocarbamate: Structure and thermal properties of the polynuclear gold-cadmium complex [Au“S2CN(iso-C4H9)2”2]2n[CdCl4]n

Abstract: Gold(III) is coordinated by binuclear cadmium diisobutyldithiocarbamate (Dtc) via chemisorption to give a heteropolynuclear Au(III)-Cd complex of the formula [Au“S2CN(iso-C4H9)2”2]2n [CdCl4] n (I). According to X-ray diffraction data, structure I contains three structurally nonequivalent complex cations [Au“S2CN(iso-C4H9)2”2]+. These cations are conformers. Relatively weak nonvalence interactions produce zigzag polymer chains of the type (...C...A...B...A...) n with alternating nonequivalent cations A, B, and C in a ratio of 2: 1: 1. The anions [CdCl4]2− are localized at the side. The calculated theoretical chemisorption capacity of cadmium Dtc with respect to [AuCl4]− is 378.0 mg of Au3+ per gram of the sorbent. To optimize the conditions for isolation of sorbed gold, the thermal properties of complex I were studied by simultaneous thermal analysis. The two-step thermolysis of complex I involves (1) thermal decomposition of the dithiocarbamate part and [CdCl4]2− with liberation of metallic gold and cadmium dichloride and (2) evaporation of CdCl2. The final thermolysis product of complex I is reduced metallic gold.

Structural features of the crystalline iodide complexes of some rare-earth elements with carbamide and acetamide

Abstract: New acetamide and carbamide complexes LnI3 · 4Ur · 4H2O (Ln = La, Eu, Dy, Ho, Y; Ur is carbamide) and LnI3 · 4AA · 4H2O (Ln = Nd, Eu, Dy, Ho, Y; AA is acetamide) are synthesized. The complexes are characterized by the data of chemical analysis, IR spectroscopy, and X-ray diffraction analysis. The ligands (water, carbamide, and acetamide molecules) are coordinated by the rare-earth element atoms through the oxygen atom, and the coordination polyhedron is a distorted square antiprism. The iodide ions are not coordinated and are located in the external sphere. The structural characteristics of the complexes are compared in the series [Ln(L)4(H2O)4]I3 (Ln = La, Nd, Eu, Gd, Dy, Ho, Er; L = AA, Ur).

Syntheses, structural determination, and binding studies of nine-coordinate mononuclear complexes (EnH2)3[EuIII(Etha)]2 · 11H2O and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O

Abstract: Two novel ethylenediaminium salt of europium complexes with aminopolycarboxylic acid ligands, (EnH2)3[EuIII(Ttha)]2 · 11H2O (I) (En is ethylenediamine, H6Ttha is triethylenetetramine-N,N,N′,N″,N‴,N‴-hexaacetic acid) and (EnH2)[EuIII(Egta)(H2O)]2 · 6H2O (II) (H4Egta is ethyleneglycol-bis(2-aminoethylether)-N,N,N′,N′-tetraacetic acid) complexes were synthesized, and their crystal structures were determined by single-crystal X-ray diffraction techniques. Both of the two complexes adopt nine-coordinate structures with the pseudo-monocapped square antiprism and crystallize in the monoclinic crystal system with the P21/n space group. The crystal data for complex I are as follows: a = 17.8262(8), b = 19.3137(5), c = 20.6233(8) A, β = 111.301(2)°, V = 6615.3(4) A3, Z = 8, ρc = 1.677 mg/m3, μ = 1.981 mm−1, F(000) = 3432, R = 0.0308, and wR = 0.0737 for 43622 observed reflections with I ≥ 2σ(I). The crystal data for complex II are as follows: a = 12.952(3), b = 12.618(2), c = 14.809(3) A, β = 105.695(2)°, V = 2330.0(8) A3, Z = 4, ρc = 1.800 mg/m3, μ = 2.765 mm−1, F(000) = 1276, R = 0.0297, and wR = 0.0638 for 18416 observed reflections with I ≥ 2σ(I). One remarkable feature of the two complexes is that the protonated [EnH22+] cations conjugating to [EuIII(Ttha)]26− and [EuIII(Egta)(H2O)]22− complex anions are reviewed, respectively, which open the path for the EuIII complexes conjugating with other various biomolecules.

Crystal structure, luminescent and thermochromic properties of bis(tetraethylammonium) hexachlorotellurate(IV)

Abstract: The crystal structure of (C2H5)4N)2TeCl6 was determined by X-ray diffraction (a = 14.130(2) A, b = 14.547(2)A, c = 13.296(2)A, β= 90.356(3)°; space group C2/c, Z = 4, ρ(calcd) = 1.387 g/cm3). The crystal structure is composed of the [TeCl6]2− anions and tetraethylammonium cations ((C2H5)4N)+. The electronic and geometric aspects that determine the spectral luminescence and thermochromic properties of the complex are discussed.

Synthesis and crystal structures of schiff base zinc(iii) complexes with antibacterial activity

Abstract: Two halide-coordinated zinc(II) complexes with the Schiff base 2-ethoxy-6-[(2-piperidin-1-ylethylimino)methyl]phenol were synthesized and structurally characterized by elemental analysis (C, H, N), FT-IR spectra, and single-crystal X-ray diffraction. The Zn atom in each complex is four-coordinated in a tetrahedral geometry by one phenolic O and one imine N atoms of the Schiff base ligand and by two halide atoms. The antibacterial activity of the complexes and the Schiff bases against the bacteria Staphylococcus aureus, Bacillus anthracis, Pseudomonas aeruginosa, and Streptococcus agalactiae was investigated.

Structures of bis(1-methyltetrazole-5-thiolato)(tetranitrosyl)diiron and its intermediates in solutions

Abstract: Single crystals of an iron complex with 1-methyltetrazole-5-thiol of the formula [Fe2(SC2H3N4)2(NO)4] (I) were obtained and examined by X-ray diffraction. According to electrochemical data, tetranitrosyl binuclear complex I rapidly decomposes in protic solvents with elimination of NO. The maximum amount of NO generated by complex I in 1% aqueous DMSO is ∼900 nmol. This amount is reduced by half 15 min after the beginning of the decomposition under anaerobic conditions. The dinitrosyl mononuclear intermediates [Fe(SC2H3N4)2(NO)]− and [Fe(SC2H3N4)2(NO)2]− were detected in solutions and identified by EPR spectroscopy and mass spectrometry. The low number of spins per complex in solutions indicates that the mononuclear complexes undergo further decomposition into NO and the species [Fe(SC2H3N4)3]−, [SC2H3N4]−, and [Fe4S3(NO)7]−. Complex I was found to be substantially more stable in DMSO than in methanol and 1% aqueous DMSO.

Quinone Complexes of Aluminum: Synthesis and Structures

Abstract: Reactions of aluminum metal with 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) in various solvents gave aluminum tris-o-semiquinolate and catecholate. The metal catecholate underwent partial hydrolysis in the presence of water. The dimeric complex [(Cat)Al(OH)Bipy]2 × 4C2H4Cl2 (Cat is the 3,6-Q dianion and Bipy is 2,2-bipyridyne) with bridging OH groups was isolated and characterized by X-ray diffraction. A reaction of aluminum with o-quinone in the presence of molecular iodine yielded the dimeric catecholate iodide [(Cat)2Al(Et2O)2]AlI2. The structure of the latter was confirmed by X-ray diffraction. An aluminum catecholato-o-semiquinolate complex was obtained by an exchange reaction between [(Cat)2Al(Et2O)2]AlI2 and thallium o-semiquinolate.

Synthesis and crystal structure of sodium isopolyvanadate [Na2(H2O)8]2H2[V10O28] · 4H2O

Abstract: The sodium hydrogen oxovanadate [Na2(H2O)8] 2H2[V10O28] · 4H2O was synthesized and studied by TGA, X-ray diffraction, and NMR and IR spectroscopy. The crystals are triclinic, space group P\( \bar 1 \), a = 8.545(7) A, b = 10.827(2) A, c = 11.627(2) A, α = 105.48(3)°, β = 99.38(3)°, γ = 101.29(3)°, V = 989.9(3) A3, ρ(calcd) = 2,381 g/cm3, Z= 1.

Synthesis, characterization, electrical conductivity, and catalytic studies of some coordination polymers of salen-type schiff base

Abstract: Coordination polymers of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), and Cd(II) with the salen-type Schiff base 4,4′-bis[(N-ethanesalicylaldehydediamine-5)azo]biphenyl have been prepared and characterized by elemental analyses, IR and electronic spectra, magnetic susceptibility measurements, and thermogravimetric analysis. Thermogravimetric analysis confirms the coordination of H2O in complexes. The 1H NMR spectrum of ligand clearly indicates the presence of OH and azomethine groups. The octahedral geometry have been suggested for Mn(II), Fe(II), Co(II), and Ni(II) complexes, and square planar Cu((II), whereas tetrahedral is suggested for Zn(II) and Cd(II) polychelates. Thermal data have been analyzed for kinetic parameters by both Coat-Redfern and Broido methods. Solid-state dc conductivity of ligand and its polychelates was measured in their compressed pellet form over 313–413 K temperature range. Solidstate conductivity lies in the range 4.361 × 10−11 to 7.241 × 10−10 Ohm−1 cm−1 indicating their semiconducting behavior. Oxidation of styrene with selected catalysts was tested using H2O2 as an oxidant.

Thermodynamics of mixed-ligand complexation of mercury(II) ethylenediaminetetraacetate with histidine and lysine in aqueous solution

Abstract: The formation of mixed-ligand complexes HgEdtaIm2−, HgEdtaL3−, HgEdtaHL2−, and (HgEdta)2L5− (L is histidine, lysine; Im is imidazole) was studied by calorimetry, pH-metry, and NMR spectroscopy. The thermodynamic parameters (logK, ΔrG 0, ΔrH, Δr S) for the reactions of complex formation at 298.15 K and ion strength of 0.5 (KNO3) were determined. The most likely coordination mode for the complexone and amino acid in the mixed complexes was identified.

New complex of zinc(II) with schiff base derived from furaldehyde and diethylenetriamine: Synthesis and crystal structure

Abstract: A new zinc(II) complex, ZnLCl2 (L = N,N′-bis(furaldehyde)diethylenetriamine), was synthesized and characterized by X-ray crystallography analysis. The crystal belongs to the triclinic crystal system, space group \( P\bar 1 \), with cell parameters a = 7.365(5), b = 13.591(9), c = 17.627(11) A, α = 94.386(12)°, β = 93.643(11)°, γ = 91.535(10)°, Z = 4, R1 = 0.0478, and wR2 = 0.0618. The coordination geometry around Zn(II) is a distorted tetrahedron containing one bidenate N,N′-bis(furaldehyde)diethylenetriamine ligand and two Cl− ions.

Cycloaddition reactions of 1-Alkyl-3,4,5-triphenyl-1,2-iphosphacyclopenta-2,4-dienes in the coordination sphere of tungsten carbonyl

Abstract: 1-Alkyl-3,4,5-triphenyl-1,2-diphosphacyclopenta-2,4-dienes react with tungsten hexacarbonyl under the conditions of “indirect” replacement of the carbonyl group to give 1: 1 complexes; [4+2] cycloaddition reactions of these complexes with maleic acid derivatives and substituted acetylenes afford tungsten carbonyl complexes containing 10-alkyl-1,10-diphosphatricyclo[5.2.1.02.6]deca-8-ene-3,5-diones and 1-alkyl-2,3-diphenylphosphirenes, respectively.

Synthesis, spectral, catalytic, and thermal studies of vanadium complexes with quadridentate schiff bases

Abstract: The paper reports the synthesis and characterization of vanadium complexes of N,N′-(±)-trans-bis(2,4-dihydroxyacetophenone)-1,2-cyclohexanediamine (H2L1) and N,N′-(±)-trans-bis(2,4-dihyroxy-5-nitroacetophenone)-1,2-chyclohexanediamine (H2L2). All the complexes were characterized by elemental analysis, magnetic susceptibility measurements, infrared and electronic spectra, and thermogravimetric analysis. The X-ray patterns of the [VO(L1)] · H2O (I) and [VO(L2)] · H2O (II) complexes show the monoclinic system with the unit cell parameters a = 26.1352, b = 11.7149, c = 6.0401 β = 115.38° and a = 29.3787, b = 12.9398, c = 5.9175 β = 96.84°, respectively. The complexes I and II catalyze the oxidation of styrene in the presence of hydrogen peroxide.

Crystal structure, DNA-binding, and fluorescence properties of cadmium(II) complex with N-(2-acetic acid)salicyloyl hydrazone and imidazole

Abstract: A novel cadmium(II) complex with N-(2-acetic acid)salicyloyl hydrazone (C9H8N2O4, H3L) and imidazole (Im) was prepared and characterized. The crystal structures of ligand H3L and cadmium(II) complex were determined by X-ray single-crystal diffractometry. The complex consists of three binuclear neutral unattached units. One of Cd2+ is six-coordinated by the carboxylic O atom, acylic O atom, and azomethinic N atom of one ligand H3L (HL2− form), carboxylic O atom from the other ligand H3L by the μ2-bridging form and N atoms from two imidazoles, but the other five Cd2+ ions all are seven-coordinated more than an O atom from coordinated water molecule compared with six-coordinated Cd2+. HL2− acts as tridentate ligand forming two stable five-numbered rings and sharing one side in the keto form for each ligand, and the carboxyl groups of two HL2− ligands are coordinated via the μ2-bridging form. The coordination polyhedron around Cd2+ was described as a octahedron or pentagonal bipyramidal. The inter- and intramolecular hydrogen bonds resulted in a three- dimensional network and provided extrastability for the structure. The complex exhibits good fluorescence properties. The complex was also searched for the interaction with CT-DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation.

Ensembles of the gallium, indium, and scandium complexes with the macrocycles

Abstract: Specific features of coordination chemistry of three-charge cations were considered for the formation of ensembles of crown ether 1,4,7,10,13,16-hexaoxocyclooctadecane (18C6) or its complexes M[18C6]+ (M = Na, K) with the gallium, indium, and scandium chloride and thiocyanate complexes. These features were geometric isomerism, disproportionation of molecular forms to ionic ones, and the influence of solvate molecules on the structural features of the supramolecular ensembles. The conditions for the recognition and stabilization of the complexes and the formation of heterometallic polymers were revealed.

Synthesis, spectroscopy, semiempirical, phytotoxicity, antibacterial, antifungal, and cytotoxicity of diorganotin(IV) complex derived from Bu2Sn(Acac)2 and 4-methyl-1-piperidinecarbodithioic acid

Abstract: New diorganotin(IV) derivative of 4-methyl-1-piperidinecarbodithioic acid (4-MePCDTA) have been synthesized by the reaction of dibutyltin(Acac)2 and ligand acid in a 1: 1 molar ratio in anhydrous chloroform at room temperature. The newly synthesized complex has been characterized by elemental, IR, and multinuclear NMR (1H and 13C). The diorganotin(IV) derivative is assessed to adopt distorted octahedral geometry in the solid state, while tetrahedral geometry is exhibited in a solution state. The modeled structure of the reported complex shows severely distorted octahedral geometry around tin. The axial tin carbon bond lengths are 2.15 A. The Sn-O bond lengths for coordinated Acac in the equatorial plane are 2.37 and 2.23 A, respectively. The complex was also tested for antimicrobial activity against different bacterial and fungal strains, artemia salina cytotoxicity, and plant phytotoxicity. The screening results show that the complex exhibits high antibacterial, antifungal, and artemia salina cytotoxicity and have a potential to be used as drug. Low phytotoxic activity shows that the reported compound can be used as agrochemical. The structure-activity relationship demonstrates that the compound having four-coordinated geometry in the solution state is more toxic.

Synthesis and solid state structures of two new copper(II) complexes of Schiff bases derived from furfuryl and tetrahydrofurfurylamine

Abstract: Two Schiff base copper(II) complexes, bis(N-furfurylsalicylaldiminato)copper(II) (I) and bis(N-tetrahydrofurfurylsalicylaldiminato)copper(II) (II), were synthesized and their solid state structures were determined by X-ray crystallography. Complex I has a square planar geometry. In contrast, complex II displays a distorted square planar geometry. Thus, the geometry around copper in the solid state structures of I and II is determined by a combination of steric and electronic effects, as well as by crystal packing forces.

Syntheses of the eight-coordinate NH4[ErIII(Cydta)(H2O)2] · 4.5H2O and (NH4)2[Er2III (Pdta)2(H2O)2] · 2H2O complexes and their structural investigation

Abstract: In this work, the title complexes, NH4[ErIII(Cydta)(H2O)2] · 4.5H2O (I) (H4Cydta = trans-1,2-cyclo-hexanediamine-N,N,N′,N′-tetraacetic acid) and (NH4)2[Er2III(Pdta)2(H2O)2] · 2H2O (II) (H4Pdta= propylene-diamine-N,N,N′,N′-tetraacetic acid), were prepared, respectively, and their composition and structures were determined by elemental analyses and single-crystal X-ray diffraction techniques. Complex I selects a mononu-clear structure with pseudosquare antiprismatic geometry crystallized in the triclinic crystal system with space group \( P\bar 1 \) and the central Er3+ ion is eight-coordinated by the hexadentate Cydta ligand and two water molecules. The crystal data are as follows: a = 8.568(3), b = 10.024(3), c = 14.377(4) A, α = 88.404(4)°, β = 75.411(4)°, γ = 88.332(4)°, V = 1194.2(6) A3, Z = 1, ρc = 1.793 g/cm3, μ = 3.586 mm−1, F(000) = 648, R = 0.0257, and wR = 0.0667 for 4169 observed reflections with I ≥ 2σ(I). Complex II is eight-coordinated as well, which selects a binuclear structure with two pseudosquare antiprismatic geometry and crystallizes in the monoclinic crystal system with space group P21/n. The central Er3+ ion is coordinated by two nitrogens and four oxygens from one hexadentate Pdta ligand. Besides, two oxygens come from one carboxylic group of the neighboring Pdta ligand and one water molecule, respectively. The crystal data are as follows: a = 12.7576(8), b = 9.3151(6), c = 14.3278(9) A, β = 96.1380(10)°, V = 1692.93(19) A3, Z = 4, ρc = 2.054 g/cm3, μ = 5.015 mm−1, F(000) = 1028, R= 0.0228, and wR = 0.0534 for 2984 observed reflections with I ≥ 2σ(I).

Synthesis and crystal structure of complex [Mn(Imdc)2(H2O)2] · 2H2O and its interaction with DNA

Abstract: Under hydrothermal conditions, the complex [Mn(lmdc)2(H2O)2] · 2H2O (I) was synthesized and characterized by elemental analysis and IR spectrum (HImdc = 4,5-imidazofedicarboxylic acid) The crystal structure of I was determined by single-crystal X-ray diffraction (crystallizing in the monoclinic crystal system, P 2/c space group, a = 11000(2), b = 71281(14), c = 12696(3) A, β = 12245(3), Z = 2 In I, the Mn2+ ion was chelated by two Imdc with one of their nitrogen atoms and a carboxylic oxygen atom, while two water molecules occupy the axial position of the Mn atom forming a distorted octahedral geometry Three-dimensional structure of I was formed by intermolecular hydrogen bonds UV-Vis and fluorescence spectra of I interacting with DNA show that insertion is the main binding mode between I and fish sperm DNA Gel electrophoresis shows that I cleaves both supercoiled and circular pBR322 DNA to form a small molecular fragment

Crystal structure of complexes of pentavalent neptunium with 1,8-bis[2-(diphenylphosphinylmethyl)]phenoxy-3,6-dioxaoctane (L) and hexavalent actinides (U, Np, Pu) with 1,8-bis[2-(diphenylphosphinyl)]phenoxy-3,6-dioxaoctane (L1)

Abstract: Complexes of pentaand hexavalent actinides with phosphoryl-containing podands incorporating a triethylene glycol fragment and 2-(diphenylphosphinyl)phenyl (L1) or 2-(diphenylphosphinylmethyl)phenyl (L) end groups were synthesized and structurally characterized The complexes can be described by the following formulas: [NpO2L(C2H5OH)(NO3)] (I) for pentavalent neptunium and [AnO2(L1)2](OH)2 · nH2O (II), where An is U (IIa), Np (IIb), and Pu (IIc), for the isostructural compounds of hexavalent actinides In I, L is a bidentate bridging ligand The Np5+ coordination polyhedron is a pentagonal bipyramid The bipyramid equatorial plane is formed by the oxygen atoms of two podands L, the bidentate nitrate ion, and the ethanol OH group The oxygen atoms of the phosphoryl groups of the podand are involved in the coordination environment of two NpO2+ cations where they connect the electrically neutral neptunoyl nitrate fragments to infinite chains along the [100] direction, which are in turn connected into ribbons by strong hydrogen bonds The crystal of II consists of the complex cations [AnO2(L1)2]2+, hydroxyl ions, and water molecules of crystallization The environment of AnO22+ is formed by four ligands L1 whose oxygen atoms form a tetragonal-bipyramidal coordination environment Each of the two crystallographically independent ligands L1 is connected to two AnO2+ cations This gives positively charged layers of actinyl cations perpendicular to the [010] direction connected by molecular ligands The layers contain channels accommodating hydroxyl ions and crystallization water molecules