Showing papers in "Russian Journal of Coordination Chemistry in 2011"

Synthesis, crystal structures, and urease inhibitory activity of cooper(II) complexes with schiff bases

Abstract: A new end-to-end thiocyanato-bridged polynuclear copper(II) complex, [Cu(CP)(μ1,3-NCS)] n · nMeOH (I), and a new mononuclear copper(II) complex, [Cu(MP)(ONO2)(OH2)] (II) (CP = 4-chloro-2-[(pyridin-2-ylmethylimino)methyl]phenolate, MP = 5-methoxy-2-[(pyridin-2-ylmethylimino)methyl]phenolate), were prepared and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. The crystal of I is orthorhombic: space group Pbca, a = 10.6161(16) A, b = 16.340(3) A, c = 18.840(3) A, V = 3268.0(9) A3, Z = 8. The crystal of II is triclinic: space group P $$ \bar 1 $$ , a = 7.5645(2), b = 8.9811(2), c = 11.9412(3) A, α = 74.4610(10)°, β = 80.5040(10)°, γ = 71.0940(10)°, V = 736.71(3) A3, Z = 2. The Cu atoms in the complexes are in square-pyramidal coordination. The biological test shows that both complexes have strong urease inhibitory activity.

Regularities of the formation of binuclear homo- and heteroleptic complexes of d metals with 3,3′-bis(dipyrrolylmethenes) in DMF

Abstract: The reactions of seven symmetrically alkylated tetradentate ligands 3,3′-bis(dipyrrolylmethenes) (H2L) with d-metal acetates (M(AcO)2) in DMF solutions at 298.15 K were studied by spectrophotometry. Helicands H2L were found to be structurally preorganized to form stable binuclear homoleptic two-helix helicates [M2L2] with Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) acetates. The coordination of the ligands by the metal ions included consecutive stages of formation of the heteroleptic [M2L(AcO)2] and homoleptic [M2L2] complexes. The [M2L(AcO)2] complexes were spectrally revealed in solutions containing a ligand excess (cH2L / cM(AcO)2 > 1). An increase in the salt concentration shifted the system of equilibria to the homoligand product [M2L2]. The thermodynamic constants of the reactions increased in the series of complexing agents: Cu(II) < Cd(II) < Hg(II) < Ni(II) < Co(II) < Zn(II). An analysis of the data on the thermodynamic constants of [M2L2] helicate formation in solutions and the earlier obtained results of the IR and 1H NMR studies of the hydrobromic salts of the ligands (H2L · 2HBr) showed that the key regularities of the influence of the structural factors on the coordination properties of the ligands were in an increase in the stability of the [M2L2] complexes with an increase in the basicity of the ligands.

Transition metal complexes with 2-(N-tosylamino)benzaldehyde 1-phthalazinylhydrazone

Abstract: 2-(N-Tosylamino)benzaldehyde 1-phthalazinylhydrazone (H2L) and its complexes with Cu(II), Ni(II), and Mn(II) were obtained. The acid-basic properties of the hydrazone were studied using potentiometry and spectrophotometry. The experimental data were compared with the results of quantum-chemical DFT calculations. The structure of the binuclear complex [Cu2L2] was determined using X-ray diffraction. The broken symmetry approach was used to calculate the exchange coupling constant of the copper ions.

A fixation mode of gold(III) in the course of the chemisorption interaction with cadmium cyclo-hexamethylene dithiocarbamate: Structural organization and thermal behavior of the heteropolynuclear complex ([Au{S2CN(CH2)6}2]2[CdCl4] · 3/4H2O)n (an example of the complicated supramolecular structure)

Abstract: The chemisorption interaction of binuclear cadmium cyclo-hexamethylene dithiocarbamate with H[AuCl4] in a solution of 2 M HCl is studied. The state of the chemisorbent is monitored by 113Cd and 13C MAS NMR spectroscopy. The result of the heterogeneous reaction, including the chemisorption of gold(III) from a solution and partial ion exchange, is the formation of the heteropolynuclear gold(III)-cadmium complex. The crystal, molecular, and supramolecular structures of the hydrated form of the synthesized coordination compound ([Au{S2CN(CH2)6}2]2[CdCl4] · 3/4H2O)n (I) are determined by X-ray diffraction analysis. Compound I includes three structurally nonequivalent complex cations [Au{S2CN(CH2)6}2]+. The character of structural differences between them indicate that they correlate as conformers: cations (A), (B), and (C) are present in the ratio 2: 1: 1. The isomeric cations perform different functions in the self-organization of the chemical system into unusually complicated supramolecular structure I. Cations (A) form centrosymmetric dimers [Au2{S2CN(CH2)6}]2+, which are involved together with cations (B) in the formation of polymeric chains ([Au2{S2CN(CH2)6}]2+ · [Au{S2CN(CH2)6}2]+)n alternating along the chain length. Cations (C) are structurally isolated, as well as anions [CdCl4]2−. The chemisorption capacity of the cadmium cyclo-hexamethylene dithiocarbamate complex calculated from the reaction of Au(III) binding is 427.2 mg of gold per 1 g of the sorbent. To establish the optimum conditions for the regeneration of bound gold, the thermal behavior of I is studied by simultaneous thermal analysis (STA). The multistage process of chemical destruction includes the desorption of hydrate water, the thermolysis of the dithiocarbamate part of the complex and [CdCl4]2− (with the release of metallic gold and cadmium chloride and the partial formation of CdS), and the evaporation of CdCl2 and CdS. The final product of thermal transformations is reduced metallic gold.

Cobalt—Sandwiched lindqvist hexaniobate dimer [Co(III)H 5 (Nb 6 O 19 ) 2 ] 8− 1

Abstract: A new polyoxoniobate K6Na2[CoIIIH5(Nb6O19)2] · 26.5H2O (I) has been synthesized by a diffusion strategy and structurally characterized by IR spectrum, UV spectroscopy, TG analysis, and single crystal X-ray diffraction. Compound I crystallizes in the cubic Pa $$\bar 3$$ space group with a = 17.969(8)A V = 5802.6(4) A3, Z = 4, R 1 = 0.0383 and wR 2 = 0.1187. Compound I consists of the Lindqvist hexaniobate dimer [CoIIIH5(Nb6O19)2]8− in which the Co3+ cations sare andwiched between and face-shared with two Lindqvist-type [Nb6O19]8− subunits. In situ UV spectra display that compound I can stably exist in an aqueous solution.

Zinc and cadmium complexes based on 3,6-di-tert-butyl-o-benzoquinone

Abstract: Zinc and cadmium bis-o-semuquinolate and catecholate complexes are synthesized by the reduction of 3,6-di-tert-butyl-o-benzoquinone (3,6-Q) with amalgamated metals in a medium of various solvents. The oxidation of the metal catecholate derivatives results in the corresponding mono-o-semiquinone complexes, which undergo symmetrization to form the metal bis-o-semiquinolates. The molecular structures of the complexes (3,6-SQ)2Zn · Py, (3,6-SQ)2Zn · H2O, and (3,6-SQ)2Cd · α,α′-Bipy (3,6-SQ is the radical anion of 3,6-Q) are studied by X-ray diffraction analysis. Magnetochemical studies are carried out for the zinc and cadmium bis-o-semiquinone complexes.

Antitumor activity of manganese(II) and cobalt(III) complexes of 2-acetylpyridine schiff bases derived from S-methyldithiocarbazate: Synthesis, characterization, and crystal structure of the manganese(II) complex of 2-acetylpyridine S-methyldithiocarbazate

Abstract: Transition metal complexes [Mn(L)2] (I) and [Co(L)2] · (ClO4) · H2O (II), where HL = 2-acetylpyridine S-methyldithiocarbazate, have been synthesized. Complex I was characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction studies. The manganese(II) atom in complex I adopts a distorted octahedral geometry with the Schiff base coordinated to it as a uninegatively charged tridentate chelating agent via the pyridine and azomethine nitrogen atoms and the thiolate sulfur atom. Biological studies carried out in vitro against K562 leukemia cancer cell line have shown that the free ligand and its metal complexes exhibited significant and different antitumor activity, since they exhibit IC50 values in the μM range.

Binary palladium carboxylates with electron-donating and electron-withdrawing substituents in the carboxylate ligand: Synthesis and structural studies. The crystal structures of Pd3(μ-CH2ClCO2)6 · CH2Cl2, Pd3(μ-C6H11CO2)6, and Pd3(μ-CMe3CO2)6

Abstract: Replacement of the acetate ligands in Pd3(μ-MeCO2)6 in benzene gave complexes of the general formula Pd3(μ-RCO2)6 (R = CF3, CCl3, CH2Cl, Me, cyclo-C6H11, and CMe3). The structures of the complexes were determined using IR spectroscopy, ESI mass spectrometry, and X-ray diffraction. It was found that the complexes contain a trinuclear Pd framework and that their spectroscopic and structural parameters depend on the donor-acceptor properties of the substituent in the carboxylate ligand.

Biological activities of pyridine-2-carbaldehyde Schiff bases derived from S-methyl- and S-benzyldithiocarbazate and their zinc(II) and manganese(II) complexes. Crystal Structure of the Manganese(II) complex of pyridine-2-carbaldehyde S-benzyldithiocarbazate

Abstract: Transition metal complexes [Zn(L1)2] (I) and [Mn(L2)2] (II), where HL1 = pyridine-2-carboxaldehyde S-methyldithiocarbazate, HL2 = pyridine-2-carboxaldehyde S-benzyldithiocarbazate, have been synthesized. Complex II was characterized by elemental analysis, IR spectra, and single-crystal X-ray diffraction studies. The manganese(II) atom in complex II adopts a distorted octahedral geometry with the Schiff base coordinated to it as a uninegatively charged tridentate chelating agent via the pyridine and azomethine nitrogen atoms and the thiolate sulfur atom. Biological studies carried out in vitro against selected bacteria, fungi, and K562 leukemia cell line, respectively, have shown that the free ligands and their metal complexes exhibited distinctive differences in the biological properties. Ligand HL1 and complex I have the marked and broad antimicrobial activities compared to HL2 and complex II while only HL1 and complex II show significant antitumor activity against K562 leukemia cell line, since they exhibit IC50 values in the μM range.

Synthesis, structures, and antimicrobial activity of nickel(II) and Zinc(II) complexes with 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol

Abstract: The Schiff base 5-methoxy-2-[(3-methylaminopropylimino)methyl]phenol (MMP) derived from 4-methoxysalicylaldehyde and N-methylpropane-1,3-diamine and its nickel(II) and zinc(II) complexes [Ni(MMP)2(NCS)2] (I) and [ZnCl2(MMP)] (II), have been prepared and characterized by elemental analyses, IR, and single crystal X-ray crystallographic determination. The crystal of I is monoclinic: space group P21/c, a = 9.0488(8), b = 12.7768(12), c = 12.9232(11) A, β = 101.927(5)°, V = 1461.9(2) A3, Z = 2. The crystal of II is orthorhombic: space group Pbca, a = 11.6991(7), b = 13.2839(8), c = 20.4451(12) A, V = 3177.4(3) A3, Z = 8. The Schiff base coordinates to the metal atoms through the phenolate O and imine N atoms. The effect of these complexes on the antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Candida albicans were studied.

Mercury(II) cyanide complexes of thioureas and the crystal structure of [(N-methylthiourea)2 Hg(CN)2]

Abstract: Mercury(II) cyanide complexes of thioureas (Tu), N-methylthiourea (MeTu), and N,N′-dimethylthiourea (DmTu)) have been prepared and characterized by IR and NMR (1H and 13C) spectroscopy, and the crystal structure of one of them was determined by X-ray crystallography. An upfield shift in 13C NMR and downfield shifts in 1H NMR are consistent with the sulfur coordination to mercury(II). The appearance of a band around 2200 cm−1 in IR and a resonance around 145 ppm in 13C NMR indicates the binding of cyanide to mercury(II). The NMR data show that the [(Thione)2Hg(CN)2] complexes are stable in solution and undergo no redistribution reactions. In the crystal structure of the title complex, mercury atom is coordinated to two thione sulfur atoms of MeTu and to two cyanide carbon atoms in a distorted tetrahedral mode with the bond angles in the range of 90.2(2)°–169.3(3)°.

Theoretical study on platinabenzene and mono- and difluorinated platinabenzenes: Structure, properties, and aromaticity

Abstract: The electronic structures and properties of the platinabenzene and mono- and difluorinated platinabenzenes isomers have been investigated using hybrid density functional B3LYP theory. Basic measures of aromatic character were derived from structure, molecular orbital, and nuclear independent chemical shift (NICS). An energetic criterion suggests that ortho isomer of monofluorinated and F15 isomer of difluorinated platinabenzenes enjoy conspicuous stabilization. The polarizability and molecular orbital analysis are compatible with this result. NICS values calculated at several points above the ring center fail to give the result consistent with that based on relative energy, polarizability, and molecular orbital analysis. The atoms in molecules analysis indicates a correlation between NICS (1.0) and the electron density of the ring critical point (ρrcp) in monofluorinated platinabenzenes. There is a similar correlation in difluorinated platinabenzenes (except for F12 and F24 isomers) between NICS (0.5) and ρrcp.

Cymantrenecarboxylate complexes of nickel(II) and cobalt(II)

Abstract: Reactions of cymantrenecarboxylic acid (CO)3MnC5H4COOH (CymCOOH) with Ni(II) and Co(II) pivalates in boiling THF followed by extraction of the products with diethyl ether or benzene and treatment with triphenylphosphine gave the binuclear complexes LM(CymCOO)4ML (M = Ni (I) and Co (II); L = PPh3). Treatment of the benzene extract of the intermediate cobalt cymantrenecarboxylate with 2,6-lutidine (L’) yielded the trinuclear complex L’Co(CymCOO)3Co(CymCOO)3CoL’ (III). Complex I is antiferromagnetic; μeff decreases from 3.7 to 0.9 μB in a temperature range from 300 to 2 K. Structures I-III were identified using X-ray diffraction. The frameworks of complexes I and II are like Chinese lanterns, having four carboxylate bridges and axial ligands L (Ni-P, 2.358(1) A; Co-P, 2.412(2) A). The metal atoms are not bonded to each other (Ni…Ni, 2.7583(9) A; Co…Co, 2808 (2) A). In complex III, either terminal Co atom is coordinated to one ligand L’ (Co-N, 2.059(2) A). The Co atoms form a linear chain showing no M-M bonds (Co…Co, 3.346(1) A), in which either terminal Co atom is linked with the central Co atom by three carboxylate bridges (on average, Cocentr-O, 2.164 A; COterm-O, 2.094 A). In one of three carboxylate groups, only one carboxylate O atom serves as a bridge, while the other is bonded to the terminal Co atom only (Coterm-O, 2.094 and 2.389 A); so this carboxylate group is a bridging and chelating ligand.

Synthesis and photoluminescence of the chiral compounds [ZnLCl2] · EtOH and ZnLCl2, where L is the (+)-3-Carene derivative containing pyrazoline and quinoline fragments: crystal structure of [ZnLCl2] · EtOH

Abstract: The following chiral compounds were synthesized: [ZnLCl2] · EtOH (I) and ZnLCl2 (II), where L is the pyrazolin-5-ol derivative obtained from terpene (+)-3-carene. According to the X-ray diffraction data, the crystal structure of compound I is built of acentric molecules of the mononuclear ZnLCl2 complex and EtOH molecules. In molecules of the complex, the Zn2+ ion is coordinated by two N atoms of the bidentate chelating ligand L and two Cl atoms at the vertices of the distorted tetrahedron. The intermolecular contacts and the hydrogen bonds Cl(1)…H-O(1) between the adjacent ZnLCl2 molecules result in the formation of chains parallel to the y axis. The reactant L and solvate I possess weak photoluminescence in the visible spectral range. Complex II exhibits more intense photoluminescence at λmax = 416 and 517 nm.

Synthesis and crystal structure of (H3O)2{(Na2(OH)CB[5])2[HV4O12]}Cl · 14H2O

Abstract: The compound (H3O)2{(Na2(OH)CB[5])2[HV4O12]}Cl · 14H2O is synthesized by heating (120°C) of a mixture of sodium vanadate, cucurbit[5]uril (CB[5]), rubidium chloride, and water in a sealed ampule. According to the X-ray diffraction data, the binding of the [Na2(OH)]+ binuclear cation with CB[5] occurs due to the bidentate coordination of the oxygen atoms of the portals of cucurbit[5]uril to the sodium atoms. The tetranuclear vanadium complex [HV4O12]3− serves as a bridge, joining infinite chains {Na2(OH)CB[5]}∞+ in pairs.

Theoretical investigation on geometries and aromaticity of heterocyclic platinabenzenes

Abstract: The electronic structure and properties of the heterocyclic platinabenzenes isomers have been investigated using the hybrid density functional B3LYP theory. Basic measures of aromatic character were derived from the structure and nucleus-independent chemical shift (NICS). The energetic criterion suggests that the ortho-isomer enjoy conspicuous stabilization where heteroatom is P or As. But the meta-isomer is most stable isomer, where heteroatom is N. The NICS values calculated at several points above the ring center to gave the result consistent with that cased on the relative energy. The atoms in molecules analysis indicates a correlation between NICS(1.0) and the electron density of ring critical point in all species. The natural bond orbital analysis has been used to study the bond characterizations in all species.

Cobalt(III) Dimethylglyoximates Containing Selenourea and an Unusual Diselenourea Ligand: Synthesis and Structures

Abstract: The complexes [Co(DH)2(Seu) y (Se-Seu) z ]2X · mSolv (DH is the dimethylglyoxime monoanion, Seu is selenourea, and X is [TiF6]2−, [ZrF6]2−) were obtained from the system CoX · 6H2O-DH2-Seu in DMF-MeOH or MeOH-H2O and examined by UV, IR, and NMR spectroscopy and X-ray diffraction. Unexpectedly, the ligand Se-Seu (the oxidized form of selenourea) was detected on the axial coordinate, partially replacing selenourea. The complexes were formulated as [Co(DH)2(Seu)1.75(Se-Seu)0.25]2[TiF6] · H2O (I) and [Co(DH)2(Seu)(Se-Seu)]2[ZrF6] · 3H2O (II). The complex cations in I and II have trans-octahedral structures. Their crystal structures are made up of the complex Co3+ cations and the outer-sphere MF 6 2− anions (M = Ti(IV) (I) and Zr(IV) (II)) held together by electrostatic interactions and hydrogen bonds; water of crystallization is also involved in hydrogen bonding.

A novel copper(II) complex with schiff base derived from o -vanillin and L-methionine: Syntheses and crystal structures

Abstract: A new Schiff base copper(II) complex, {[CuL(H2O)2][CuL(H2O)]3 · 4H2O · C3H7NO} n (H2L = (Z)-2-(2-hydroxy-3-methoxybenzylideneamino)-4-(methylthio)butanoic acid), was synthesized and characterized by IR, UV, and X-ray diffraction single-crystal analysis. The crystal belongs to the triclinic crystal system, space group with cell parameters a = 5.2027(5) A, b = 16.6916(16) A, c = 20.237(2) A, α = 88.895(10)°, β = 84.127(1)°, γ = 83.577(10)°, V = 1737.2(3) A3, Z = 1, F(000) = 848, S = 1.042, ρcalcd = 1.561 g cm−3, μ = 1.411 mm−1, the final R 1 = 0.0760 and wR 2 = 0.2318 for 6030 observed reflections (I > 2σ(I)). The crystal structure of the complex contains two independent units with different coordination environments. In independent unit 1, the Cu(1) is five-coordinated by one nitrogen atom and two oxygen atoms from the Schiff base ligand and two oxygen atoms from two water molecules to form a distorted square pyramid geometry. On the other hand, in independent unit 2, the Cu(2) is five-coordinated and possesses a slightly distorted square-pyramidal coordination geometry, defined by one nitrogen atom, one hydroxyl oxygen atom, two carboxylate oxygen atoms in two different ligands, and one oxygen atom of the water molecule. The complex forms a one-dimensional chain polymer in the xy plane through carboxyl oxygen atoms in the Schiff base ligands.

Secondary interactions in the crystal structure of heterovalent 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III) dibromoaurite(I)

Abstract: The complex [Au(C14H22N4)][AuBr2] with two types of gold atoms (Au(III) and Au(I)) was obtained. In the cation 5,7,12,14-tetramethyl-1,4,8,11-tetraazacyclotetradeca-4,6,11,13-tetraenatogold(III), the Au atom is coordinated by four N atoms of the tetraazamacrocyclic amide ligand to make up a distorted square. The dibromoaurite(I) anion is linear. The conformation and packing of the structure is determined and stabilized by weak intermolecular hydrogen bonds C-H…Br and C-H…Au, an aurophilic interaction Au(I)…Au(III), and coordination bonds Au…N.

Synthesis and Structure of (Acetylacetonato κ 2 O,O')(bistriphenylphosphine)palladium Tetrafluoroborate as a Precursor of Catalysts Active in the Conversion of Unsaturated Hydrocarbons

Abstract: An X-ray diffraction analysis is carried out for the complex [Pd(Acac)(PPh3)2]BF4 (I), which is a precursor of the active complexes of styrene dimerization and norbornene additive polymerization in the system [(Acac)Pd(PPh3)2]BF4-BF3 · OEt2. In complex I the palladium atom is coordinated by two oxygen atoms of the acetylacetonate ligand and two phosphorus atoms of the triphenylphosphine ligands at the vertices of the distorted square.

Transition metal complexes with “non-innocent” ligands in the activation of hydrogen sulfide

Abstract: The reactions of hydrogen sulfide with transition metal complexes containing redox-active ligands are studied. A combination of electrochemical and spectral data indicates that the one-electron process affording the hydrogen sulfide radical and monoanionic complexes is an elementary act for the most part of the reactions studied. The accessibility of the metal center in the Co, Ni, Zn, and Pt complexes allows hydrogen sulfide to preliminary coordinate to the metal followed by the inner-sphere electron transfer in the hydrogen sulfide-metal-organic ligand system. Active intermediates (radical cation, thiyl radical, and proton) formed due to oxidation react with aromatic substrates. The substitution reaction in the aromatic ring produces a mixture of isomeric thiols and dimerization products of organylthiyl radicals (disulfides).

Formation of shortened partially multiple bonds of transition metals with carbenoid compounds of heavy p elements of groups III–VII as a reason for the occurrence of the HSAB principle

Abstract: The universal character of the phenomenon of sharp (from 0.15 to 0.3 A) shortening of formally ordinary bonds between transition metals (M) and heavy nontransition elements (Q) of Groups III–VII (Periods III–V) compared to the sum of covalent radii is shown for numerous examples of the complexes described in the literature or studied by the author and coworkers. In the most part of cases, this shortening occurs without an elongation of Q-X bonds in ligands and, hence, the main reason for M-Q bond shortening is considered to be an additional dative interaction of a lone electron pair at the M atom with vacant d orbitals of the indicated nontransition elements. The appeared partial multiplicity of formally ordinary M-Q bonds is assumed to be a physical basis for the preferential interaction of soft acids with soft bases in terms of the HSAB concept.

High-temperature spin transition in the iron(II) trifluoromethylsulfonate, perrhenate, and tetraphenylborate complexes with tris(pyrazol-1-yl)methane

Abstract: New coordination compounds of iron(II) trifluoromethylsulfonate, perrhenate, and tetraphenylborate with tris(pyrazol-1-yl)methane (HC(Pz)3) of the composition [Fe(HC(Pz)3)2]A2 (A = CF3SO3 − (I), ReO4 − (II), and B(C6H5)4 − (III)) were synthesized and studied by the method of static magnetic susceptibility and IR and electronic spectroscopies. The crystal and molecular structures of compounds I and II were determined by X-ray diffraction analysis. The magnetochemical study of complexes I—III in the interval from 275 to 500 K showed that they possessed the high-temperature spin transition 1 A 1 ⇄ 5 T 2 accompanied by thermochromism.

Polynuclear complexes of gold(III) of the composition ([Au(S2CNR2)2][AuCl4]) n (R = C4H9, R2 = (CH2)5): Synthesis, supramolecular structures, and thermal behavior

Abstract: The interaction of binuclear cadmium dialkyldithiocarbamates [Cd2(S2CNR2)4] with solutions of AuCl3 in 2M HCl gives polynuclear gold(III) complexes ([Au(S2CNR2)2][AuCl4])n, where R = C4H9 (I) and R2 = (CH2)5 (II). The structures of the synthesized compounds solved by X-ray diffraction analysis are char-acterized by a complicated organization at the supramolecular level. The structures are based on polymer chains (I) and layers (II) involving isomeric cations [Au(S2CNR2)2]+ and anions [AuCl4]−. The thermal behavior of the synthesized complexes is studied by simultaneous thermal analysis including thermogravimetry and differential scanning calorimetry. The final product of the thermal transformations of the studied complexes is shown to be reduced metallic gold.

Synthesis, characterization, and X-ray crystal structures of zinc(II) complexes with schiff bases 2-[(2-isopropylaminoethylimino)methyl]-5-methoxyphenol and N,N-dimethyl-N′-(1-pyridin-2-ylethylidene)ethane-1,2-diamine

Abstract: Two new zinc(II) complexes, [ZnBr2L1] (I) and [ZnBr2L2] (II), where L1 is 2-[(2-isopropylaminoethylimino)methyl]-5-methoxyphenol and L2 is N,N-dimethyl-N′-(1-pyridin-2-yl-ethylidene)ethane-1,2-diamine, were prepared and characterized using elemental analysis, FT-IR spectroscopy, and X-ray single-crystal diffraction In complex I, the Zn(II) atom is coordinated by one phenolic O and one imino N atoms of L1 and two Br atoms, forming a tetrahedral coordination geometry In complex II, the Zn(II) atom is in a trigonal bipyramidal coordination geometry with the equatorial plane formed by the imino N atom of L2 and two Br atoms and with the two axial positions occupied by one pyridine N and one amino N atoms of L2 In the crystal structure of I, the mononuclear zinc complex molecules are linked through intermolecular N-H…O and N-H…Br hydrogen bonds, forming chains running along the y axis The chains are further linked via intermolecular C-H…Br hydrogen bonds In the crystal structure of II, the mononuclear zinc complex molecules are linked through intermolecular C-H…Br hydrogen bonds, forming a 3D network

First example of the planar rectangular 18-nuclear nickel(II) hydroxo complex with n-(2-pyridylmethyl)iminodipropionic acid

Abstract: A planar rectangular cluster Ni18 (I) was obtained from N-(2-pyridylmethyl)iminodipropionic acid (II). The crystal structure of complex I was determined by X-ray diffraction. Complex I is built from the octanuclear planar framework (III) of the nickel(II) hydroxo complex (Ni...Ni 2.976–3.092 A), four nickel chelates with the corresponding acid (IV), which are coplanar with the framework and are on both its sides (Ni...Ni, 2.938–3.188 A), four hydroxo complexes, and two mixed chloro chelates V), which are not coplanar with the framework (Ni...Ni, 3.141 and 3.181 A). In the chelate parts of complex I, the organic ligand is hexadentate because of bridging bonds; the coordination polyhedroLn of the metal center is a distorted square bipyramid (4 + 2).

Synthesis and luminescence properties of the Pr(III), Sm(III), Eu(III), Nd(III), and Yb(III) complexes with propane-1,3-dione derivatives

Abstract: The luminescence method, mass spectrometry, and elemental analysis are used to reveal that under optimal conditions (pH 5–8) Ln3+ ions (Ln = Pr, Sm, Eu, Nd, and Yb) with 1-(2-hydroxy-4-methylphenyl)-3-(5-methyl-1-phenyl-1 H-1,2,3-triazol-4-yl)propane-1,3-dione form complexes with the mole ratio Ln: ligand = 2: 3. According to the IR spectral data, Ln3+ ions coordinate three oxygen atoms of two carbonyl groups and one hydroxyl group. In the IR spectra of the complexes, an intense band at 628.7 cm−1 is assigned to the Ln-O bond vibrations. The X-ray diffraction patterns of the complexes contain no lines corresponding to the ligand. The luminescence intensity of the complexes in the visible spectral range changes in the series Eu(III) > Sm(III) > Pr(III), whereas in the IR region the order is Yb(III) > Nd(III). In all cases, luminescence of the solid complexes is considerably more intense than that of their solutions.

Crystal structure and magnetic properties of the binuclear copper(II) complex based on 1,3-diaminopropan-2-ol N,N′-bis(3-formyl-5- tert -butylsalicylidene)

Abstract: 1,3-Diaminopropan-2-ol N,N′-bis(3-formyl-5-tert-butylsalicylidene) (H3L) and the binuclear copper(II) complex based on H3L, [Cu2L(CH3COO)] (I), are synthesized. The compounds are studied by IR and 1H NMR spectroscopies, magnetochemistry, and X-ray diffraction analysis. Compared to the copper(II) complexes with 1,3-diaminopropan-2-ol N,N′-bis(salicylidene), complex I is characterized by a substantial change in the structure resulting in weakening of the antiferromagnetic exchange interaction.

Hydrothermal synthesis and crystal structure of a new 2D metal-organic framework: [Zn(Btca)(Phen)] n (H2Btca = benzotriazole-5-carboxylic acid, phen = 1,10-phenanthroline)

Abstract: A new coordination polymer, [Zn(Btca)(Phen)]n (I) (H2Btca = benzotriazole-5-carboxylic acid, Phen = 1,10-phenanthroline), has hydrothermally been synthesized by the reaction of zinc nitrate, H2Btca and Phen in the presence of DMF and H2O. Single-crystal X-ray diffraction analysis reveals that in complex I the metal centers are linked by the bridging Btca ligand to form an extended two-dimensional wave-like layer decorated by Phen.

Syntheses, structural determination and binding studies of nine-coordinate mononuclear (EnH2)1.5 [ErIII(Ttha)] · 3H2O and (EnH2)[ErIII(Egta)(H2O)]2 · 6H2O

Abstract: In this work, the title complexes, (EnH2)1.5[ErIII(Ttha)] · 3H2O (I) and (EnH2)[ErIII(Egta)(H2O)]2 · 6H2O (II), where En = ethylenediamine, H6Ttha = triethylenetetramine-N,N,N′,N″,N″’,N″′-hexaacetic acid, H4Egta = ethyleneglycol-bis-(2-aminoethylether)-N,N,N′,N′-tetraacetic acid, have been successfully synthesized. Their structures have been characterized by IR spectroscopy and single-crystal X-ray diffraction techniques. The X-ray diffraction reveals that I is nine-coordinated and crystallizes in the monoclinic crystal space group P2/n with cell dimensions a = 17.6058(16), b = 9.6249(9), c = 20.560(2) A, β = 109.7440(10)°, and V = 3279.1(5) A3. Compound II is also nine-coordinated and crystallizes in the monoclinic crystal space group P21/n with the cell dimensions a = 12.938(6), b = 12.651(5), c = 14.943(6) A, β = 105.441(5)°, and V = 2357.5(17) A3. In I, each EnH 2 2+ cation connects three adjacent [ErIII(Egta)(H2O)]− complex anions through hydrogen bonds, while in I, there are two types of EnH2 2+ anions. One is highly symmetrical, forming hydrogen bonds with two neighboring [ErIII(Ttha)]3− complex anions. The other anion connects three adjacent [ErIII(Ttha)]3− complex anions through hydrogen bonds. These hydrogen bonds lead to the formation of 2D ladder-like layer structure.