Showing papers in "Journal of Coordination Chemistry in 1998"
TL;DR: In this paper, the authors summarized the data for over nine hundred dimeric Cu(II) coordination compounds and found that the most common ligands are O− and N− donors.
Abstract: This review summarizes the data for over nine hundred dimeric Cu(II) coordination compounds. There are several types of the bridges, from which doubly bridges by far prevail. The most common ligands are O− and N− donors. From the stereochemical point of view, a square-pyramidal arrangement with different degrees of distortion about Cu(II), is the most common. Several relationships were found between the Cu-Cu distances and the Cu-L-Cu bridge angle and the type of bridging, between the intra-ligand L-Cu-L ring angles and coordination numbers.
67 citations
TL;DR: In this paper, the syntheses and crystal structures of [Co(nic)2(H2O)4] and [Cu(iso)2 (H2E) 4] are reported, and the arrangements around the metal ions are trans-octahedra with two pyridyl nitrogens and two aqua oxygens in the equatorial positions and two Aqua oxygen in the axial positions.
Abstract: The syntheses and crystal structures of [Co(nic)2(H2O)4] (1). [Co(iso)2(H2O)4] (2). [Cu(nic)2(H2O)4] (3), and [Cu(iso)2(H2O)4] (4) (nic = nicotinate; iso = isonicotinate) are reported. Complex 1 crystallizes in monoclinic, space group C2/m with cell parameters a =14.150(4). b = 6.883(2)., c = 8.497(2) A, β= 118.28(2)° and Z = 2. The other crystals. 2. 3. and 4. are all triclinic, PĪ; a = 9.777(3), b = 6.348(4), c = 6.888(3)A, a= 113.10(6)., β= 110.55(3). γ = 97.61(5)°, and Z=l for 2; a = 7.0281(4), b = 7.7176(6), c = 8.6978(7)A, a = 68.103(7), β = 68.526(5), γ = 62.550(6)°, and Z=1 for 3; a = 9.1807(4), b = 6.3334(3), c = 6.8871(3)A, a= 108.213(4), β = 99.433(4), γ= 105.190(4)°, and Z= 1 for 4. The arrangements around the metal ions are trans-octahedra with two pyridyl nitrogens and two aqua oxygens in the equatorial positions and two aqua oxygens in the axial positions, although the Cu(II) complexes show a larger Jahn-Teller distortion.
63 citations
TL;DR: In this paper, four different types of metallosupramolecular structures are distinguishable for the title complexes: (a) the metal complex could react with other metal ions as a ligand, (b) Dimerization occurs through Lewis acid and Lewis base interactions of the metal ion and the coordinated oxygen atom of the ligand with those of an adjacent molecule, (c) denoising and chain formation occur using the donor-acceptor behaviour of the oxovanadium (IV) ion, and (d) molecular association occurs through the bridged fluoride.
Abstract: Four different types of metallosupramolecular structures are distinguishable for the title complexes. These types are described as: (a) The metal complex could react with other metal ions as a ligand, (b) Dimerization occurs through Lewis acid and Lewis base interactions of the metal ion and the coordinated oxygen atom of the ligand with those of an adjacent molecule, (c) Dimerization and chain formation occur using the donor-acceptor behaviour of the oxovanadium (IV) ion, and (d) Molecular association occurs through the bridged fluoride. Types (b), (c) and (d) are self-assembly. Chemical understanding of those types could lead to designing, and establishing procedures for, the preparation of new metallosupramolecular structures of homo- and heterobinuclear (as well as polynuclear) metal complexes with similar or mixed ligands.
46 citations
TL;DR: In this article, Thioureide vC-N bands for Cd(nmedtc) and Hg(padtc)2 have been shown to appear at relatively low energy due to the large sizes of the cadmium and mercury ions in comparison with zinc.
Abstract: M(nmedtc)2 and M(padtc)2 (where nmedtc− = N-methyl-N-ethanol-dithiocarbamate anion; padtc = N,N1 -(iminodiethylene)bisphthalimidedithiocarbamate anion; M = Zn(II), Cd(II), Hg(II)) complexes were synthesized and characterized. Zinc and cadmium complexes are tetra-hedral. Splitting of the vC-S band in Cd(nmedtc)2 indicates anisobidentate coordination of the ligand. The mercury analogue is polymeric. Thioureide vC-N bands for Cd(nmedtc)2 and Hg(padtc)2 appear at relatively low energy due to the large sizes of the cadmium and mercury ions in comparison with zinc. Thermal studies have been carried out. Unit cell constants of Zn(deadtc)2 are a = 29.017(2)A, b = 8.611(4)A, c= 14.045(2) A, β= 103.2(1)°, space group C2/c. The coordination polyhedron is a distorted trigonal bipyramid. Thioureide C-N is 1.489(5) A, which is significantly longer than observed in the corresponding diethyl analogue (1.325(9) A). Zn-Zn' is 3.485(3) A compared to 3.546(3) A observed in the diethyl analogue.
33 citations
TL;DR: In this article, a dinuclear structure based on octahedrally coordinated metal ions is proposed, which is characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible).
Abstract: The reaction, in water, of Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) ions with sodium ampicillinate at room temperature has allowed isolation of dimers with the following general formula [M(amp)Cl]2 × nH2O (n = 1.5−3.2). The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibilities and spectroscopic methods (IR, Raman, EPR and UV-Visible). A dinuclear structure based on octahedrally coordinated metal ions is proposed.
29 citations
TL;DR: In this article, the exchange kinetics of the lithium ion with cryptand C222 were studied in acetonitrile-nitromethane mixtures by lithium-7 NMR line-shape analysis.
Abstract: The exchange kinetics of the lithium ion with cryptand C222 were studied in acetonitrile-nitromethane mixtures by lithium-7 NMR line-shape analysis. In all solvent mixtures used, and over the entire temperature range studied, the chemical exchange of the Li+ ion between the solvated and complexed sites was found to occur via a bimolecular mechanism. The activation parameters Ea, δH‡, δS‡ and δG‡ for the exchange have been determined. The free energy barrier for the exchange process appears to be nearly independent of the binary mixture composition. The results confirm the preferential solvation of the lithium ion with acetonitrile in the binary mixed solvent systems used.
27 citations
TL;DR: In this paper, the pH control during workup allows synthesis of TPPTS without interference from the oxide, and the recrystallized yield is 70% based on P(m-C6H4SO3Na)3 3H2O from PPh3.
Abstract: Controlling the pH during workup allows synthesis of TPPTS. P(m-C6H4SO3Na)3, without interference from the oxide. The recrystallized yield is 70% based on P(m-C6H4SO3Na)3 3H2O from PPh3.
24 citations
TL;DR: In this article, a novel dioxime having the 1,3-oxolane group, l,2-dihydroxyimino-3,7-di-aza-9,10-O-cyclohexylidene decane (H2L), has been synthesized from the reaction of l, 2-O-, cyclohexylonidene-4,aza-7-amino heptane and anti-chloroglyoxime.
Abstract: In this study, a novel dioxime having the 1,3-oxolane group, l,2-dihydroxyimino-3,7-di-aza-9,10-O-cyclohexylidene decane (H2L), has been synthesized from the reaction of l,2-O-cyclohexylidene-4-aza-7-amino heptane and anti-chloroglyoxime. Complexes of this ligand with Ni(II), Co(II), Cu(II) and UO2(VI) salts were prepared. The structure of the ligand and its complexes is proposed from the 1H and 13C-NMR, IR, mass spectral data, elemental analysis and magnetic susceptibility measurements. In addition, thermal properties of H2L and its complexes were also investigated by thermogravimetric analyses (TGA) and differential thermal analyses (DTA).
24 citations
TL;DR: In this article, a Schiff base derived from 2-hydroxyacetophenone and ethylenediamine (hapenH2) with M(CO)6, M = Cr and Mo, in THF under atmospheric pressure gave the oxo derivatives M(O)(hapen) with the metal atom in +4 formal oxidation state.
Abstract: Interaction of a Schiff base derived from 2-hydroxyacetophenone and ethylenediamine (hapenH2) with M(CO)6, M = Cr and Mo, in THF under atmospheric pressure gave the oxo derivatives M(O) (hapen) with the metal atom in +4 formal oxidation state. IR spectra of the complexes revealed the presence of the M = O bond. The dihydride complex MoH2(CO) (hapen) was also isolated from the reaction of Mo(CO)6 and happen H2 under reduced pressure; v(CO) and v(Mo-H) frequencies were clearly indicated in its IR spectrum. The three complexes were found to be paramagnetic. Magnetic susceptibility measurements suggested that the d 4 Mo atom in MoH2 (CO) (hapen) exists in a low spin configuration. Electronic spectra of the ligand and its complexes in different donor solvents displayed bands due to compound-solvent, charge-transfer complexes.
23 citations
TL;DR: In this paper, the sodide (IUPAC, natride) salts, including sodide salts, have been obtained for crystal structures for sodide and other alkalides, and the synthesis, handling and crystal growth techniques are described and the properties and structures are compared with those of other alkalinides.
Abstract: Crystal structures have been obtained for the sodide (IUPAC, natride) salts, K+(12–crown–4)2–Na− (I), Na+(cryptand[2.2.1])Na−(II), Rb+(18–crown–6)Na−·CH3NH2 (III), K+(18–crown–6) Na−·2(CH3NH2)·3(18–crown–6)(IV), Cs+(cryptand[3.2.2])Na−(V), and (Li+)2(TMPAND)2–(Na−)2·(CH3NH2)(VI), in which TMPAND is 5,12,17–trimethyl–1,5,9,12,17–pentaazabicyclo [7.5.5] nonadecane). The synthesis, handling and crystal growth techniques are described and the properties and structures are compared with those of other alkalides.
22 citations
TL;DR: The structure of a thermochromic complex, bis(N,N−diethylethylenediamine)copper(II) tetrafluoroborate [CuL2(BF4)2] having the lowest transition temperature (24°c) amongst its isomorphous counterparts (ClO4 − salts of Cu and Ni) has been determined at 22°c thus offering a unique opportunity to study near transition structural parameters.
Abstract: The structure of a thermochromic complex, bis(N,N–diethylethylenediamine)copper(II) tetrafluoroborate [CuL2(BF4)2] having the lowest transition temperature (24°c) amongst its isomorphous counterparts (ClO4 − salts of Cu and Ni) has been determined at 22°c thus offering a unique opportunity to study near transition structural parameters. The Cu atom at the crystallographic centre of inversion has square planar coordination from four N–atoms of two centrosymmetrically related ligands [Cu[sbnd]N(secondary) = 2.061(5), Cu[sbnd]N(primary) = 2.003(6) A, bite angle N[sbnd]Cu[sbnd]N = 84.6(2)°], the diethyl group orientations insulate the metal ion from anion coordination [closest approach (Cu…F3 = 3.621(4) A)]. The thermal anisotropies of the chelate ring carbons are normal and do not indicate any disorder, although the structure is determined at a temperature (π22°c) very close to the transition. The highest thermal vibrations are shown by the BF4 − anion and then to some extent by the terminal C-atoms...
TL;DR: Both theoretically possible geometrical isomers, facial and meridional, of uns-cis-(ethylenediamine-N, N′-di-3-propionato)(glycinato)cobalt(III) semi hydrate have been prepared by reaction of sodium uns-Cis-(methylenediamines-N) with carbonato) with glycine at 75°C.
Abstract: Both theoretically possible geometrical isomers, facial and meridional, of uns-cis-(ethylenediamine-N, N′-di-3-propionato)(glycinato)cobalt(III) semi hydrate have been prepared by reaction of sodium uns-cis-(ethylenediamine-N, N′-di-3-propionato) (carbonato) cobaltate(III) with glycine at 75°C. The complexes have been isolated chromatographically and characterized by elemental analysis, electron absorption, infrared and nuclear magnetic spectra.
TL;DR: In this paper, the crystal and molecular structure of [Ni(dpta)(ttcH)(H2O)] H2O was determined by means of elemental analysis, IR and electronic spectroscopies and magnetochemical measurements.
Abstract: Nickel(II) complexes with a combination of trithiocyanuric acid and diamines or triamines of composition [Ni(aepa)(ttcH)(H2O)], [Ni(dien)(ttcH)(H2O)], [Ni(dpta)(ttcH)(H2O)] H2O, [Ni(phen)2(ttcH)]H2O, [Ni(phen)3](ttcH)-5H2O and [Ni(1,2-pn)3](ttcH)-H2O (aepa = N-(2-aminoethyl)-1,3-propanediamine,dien = diethylenetriamine,dpta = dipropylenetnamine, phen = 1,10-phenanthroline, 1,2-pn = 1,2-diaminopropane. ttcH3 = trithiocyanuric acid) have been prepared. The compounds have been characterized by means of elemental analysis, IR and electronic spectroscopies and magnetochemical measurements. Selected complexes were studied by thermal analysis. The compounds can be characterized as distorted octahedral Ni(II) complexes. It was found that the trithiocyanuric dianion can act either as a bidentate ligand or be situated out of the coordination sphere of nickel. The crystal and molecular structure of [Ni(dpta)(ttcH)(H2O)] H2O was determined. Crystals are monoclinic, space group P21/n, with a = 20.316(4), b = ...
TL;DR: In this article, a mixed 1:2 manganese-azido complex of ethyl nicotinate has been synthesized and characterized by spectroscopic and crystallographic methods.
Abstract: A mixed ligand 1:2 manganese(II) azido complex of ethyl nicotinate has been synthesized and characterized by spectroscopic and crystallographic methods. The structure consists of a two-dimensional manganese-azido compound with each manganese atom in a trans octahedral environment, bonded to four azido ligands [Mn−N = from 2.199(4) A to 2.231(3) A] and two axial ethyl nicotinate ligands [Mn-N = 2.285(3) and 2.308(3) A]. Two azido ligands are coordinated end-on between the manganese atoms giving planar and centrosymmetric Mn2N2 units. Each Mn2N2 unit is linked to four neighboring Mn2N2 units by means of four end-to-end azido bridges. The IR and Raman spectra correlate with the structure of the complex. The vibrational bands are compared with those of the free ligand. The EPR spectra of polycrystalline powder and solutions of the complex are measured at room temperature and discussed. The thermal decomposition of the complex was investigated derivatographically under nitrogen.
TL;DR: In this paper, the 7FO→5DO excitation spectroscopy of the Eu3+ ion was studied by using multilinear regression with the present set of 22 complexes.
Abstract: The complexation of ethylenediamine, triethylenetetramine, acetic acid, glutaric acid, succinic acid, maleic acid, fumaric acid, malonic acid, iminodiacetic acid, nitrilotriacetic acid, N-(2-hydroxyethyl)ethylenediaminetriacetic acid, N 1-(4-isothiocyanatobenzyl)di-ethylene-triaminetetraacetic acid, trans-1, 2-diaminocyclohexane-N, N, N, N'-tetraacetic acid and diethylenetriaminepentaacetic acid (DTPA) with Eu3+ ion in aqueous solution has been studied by using the 7FO→5DO excitation spectroscopy of the Eu3+ ion. Because the energy of the 7FO→5DO transition of Eu3+ is dependent on the coordinating oxygen atoms, the “nephelauxetic” shift parameters for most typical coordinating atoms, such as in the carboxylate group, aliphatic amino nitrogen and the pyridine nitrogen atom were recalculated by multilinear regression with the present set of 22 complexes. The calculated shift parameters were used for the analysis of the excitation spectra of the complexes of diethylenetriaminepentaacetic acid, trans...
TL;DR: The green Cu(nif)2(denc)2 (nif = niflumate, dene = diethylnicotinamide) crystallizes in the triclinic system, space group P-1 with unit cell parameters as mentioned in this paper.
Abstract: The green Cu(nif)2(denc)2 (nif = niflumate, dene = diethylnicotinamide) crystallizes in the triclinic system, space group P-1 with unit cell parameters: a = 7.984(2)A. b = 12.270(2)A, c = 12.904(3)A, a = 75.23(3)°, β= 71.22(3)°, γ= 72.04(3)° and Z= 2. The final R value for 5325 independent reflections is equal to 0.0455. The structure is centrosymmetric. The Cu(II) atom is pseudo-octahedrally trans-coordinated by four carboxylic O atoms of two niflumate anions, Cu-O bond distances being 1.955(2) (2×) and 2.643(2)A (2×), and by two N atoms from two N,N-diethyl- nicotinamide ligands, Cu - N bond distance is 2.007(3)A (2×). An EPR spectrum of the complex is of the axial type with gII > g⊥ and S = 1/2. Magnetic data of the complex obey the Curie-Weiss law with a small positive value of the Weiss constant (6.6K) indicating a weak ferromagnetic interaction.
TL;DR: In this article, the synthesis and characterization of mefanamate (mef) compounds of composition Cu(mef), 2L (L = water, caffeine, or methyl-3-pyridylcarbamate) and Cu( mef)2L2 (L= 3pyridine carbinol, nicotinamide, N,N-diethyl nicotine, 2,6-dimethanol pyridine or nicotine) is reported.
Abstract: The synthesis and characterization of Cu(II) mefanamate (mef) compounds of composition Cu(mef)2L (L = water, caffeine, or methyl-3-pyridylcarbamate) and Cu(mef)2L2 (L = 3-pyridylcarbinol, nicotinamide, N,N-diethylnicotinamide, 2,6-dimethanol pyridine or nicotine) is reported. Characterizations of the compounds were based on elemental analyses, electronic, infrared and EPR spectra and magnetic susceptibility measurements over a temperature range (80–290 K). The spectral and magnetic properties of Cu(mef)2L indicate the presence of Cu(II) dimers structurally similar to that of Cu(II) acetate monohydrate. All the Cu(mef)2L2 compounds possess octahedral stereochemistry about Cu(II) with differing tetragonal distortion. An X-ray analysis of Cu(mef)2(Et2nia)2(H2O)2was carried out, and it featured tetragonal bipyramidal geometry around the Cu(II) atom. The tetragonal plane is created by mefanamate anions bonded to the Cu(II) atom via the unidentate carboxylate oxygen atoms [Cu-0(2) = 1.936(3)A] and the ...
TL;DR: In this paper, the triclinic structure of Strontium-II djhydrate is described and the coordination around the Sr ion is ninefold: seven oxygen and two nitrogen atoms make a distorted, mono-capped square antiprism.
Abstract: Triaquo(μ-pyrazine-2,5-dicarboxylato)strontium(II) djhydrate, SrC6HI2N2O9 crystallizes in the triclinic system, space group PĪ, a = 6.238(l)A, b = 9.418(2)A, c= 10.591(2)A, a = 73.58(3)°, β = 80.52(3)°, γ = 75.01(3)°, Z = 2. The structure is polymeric. Strontium ions are bridged by pyrazine-2,5;dicarboxylic acid molecules which use both (N,O)-bonding moieties (mean Sr-O = 2.567(3) A, mean Sr-N = 2.826(3) A). In addition, the bridging is accomplished by two oxygen atoms from water molecules (mean Sr-O = 2.681(3) A) and bidentate oxygen atoms (Sr-O = 2.697(3) A) from a carboxylic group of a pyrazine-2,5-dicarboxylic acid molecule. As a result, a three-dimensional molecular framework is formed. The coordination around the Sr ion is ninefold: seven oxygen and two nitrogen atoms make a distorted, mono-capped square antiprism. Two water molecules per unit cell are situated in the holes of this framework and participate in an extended hydrogen bond scheme.
TL;DR: In this paper, the crystal and molecular structure of thetetrakis(μ-propionato)di(methyl-3-pyridinecarbamate) dicopper(II), Cu-2(prop)4(mpc)2, was determined by direct method and Fouriertechniques.
Abstract: New copper(II) propionate compounds of composition Cu(prop)2L (L =methyl-3-pyridylcarbamate or N, N-diethylnikotinamide) andau(prop)2L2 (L = methyl-3-pyr-idylcarbamate or2, 6-pyridinemethanole) have been prepared. The crystal and molecular structure of thetetrakis(μ-propionato)di(methyl-3-pyridinecarbamate) dicopper(II), Cu-2(prop)4(mpc)2, was determined by direct method and Fouriertechniques. The compound crystallizes in the orthorhombic space group Pcab with four dimeric units in a cell withdimensions a = 19.350(4), b = 15.390(3), c = 10.725(2)A. The structure was refined byfull-matrix least-squares methods to a R factor of 0.031, based on 3666 independent reflections. Thecompound is dimeric, with square-pyramidal geometry at each copper centre. The two copper atoms are bridgedby four carboxylate groups, while the apical ligands are methyl-3-pyridylcarbamate. The structural dataare compared with those found in similar copper(II) propionates. Spectral data of Cu(prop)2L aretypical for dimeric co...
TL;DR: In this paper, the structure of pyrazine-2,5-pzdc and water molecules held by a system of hydrogen bonds is described, and the interlayer spacing of 3.2 A indicates interactions of the van der Waals type.
Abstract: Pyrazine-2,5-dicarboxylic acid dihydrate, C4H2N2(COOH)2. 2H2O, is triclinic, Pl. a = 5.255(1)A, b = 6.907(1) A, c = 6.951(l)A, a= 119.(3)°, β= 100.81(3)°, γ = 99.06(3)°, Z = 1. The structure is composed of molecular layers consisting of 2,5-pzdc and water molecules held by a system of hydrogen bonds. The interlayer spacing of 3.2 A indicates interactions of the van der Waals type. Magnesium pyrazine-2,5-dicarboxylate hexahydrate, [Mg(H2O)6][C4H2N2(COO)2], is mono-clinic, P21/c, a = 8.016(l)A, b = 6.858(1)A, c= 11.278(1)A, β = 99.52(3)°, Z = 2. Each magnesium atom is surrounded by six water molecules located at the apices of an almost regular octahedron with mean dMg-O = 2.060(1)A. The 2,5-pzdc anions are planar with interatomic distances and angles characteristic for the pyrazine ring. A number of hydrogen bonds link the water molecules coordinated to Mg with carboxylic oxygens of the acid molecules. Their lengths range from 2.51 A to 3.07 A.
TL;DR: In this article, the stoichiometrics and stability constants of the nickel(II), copper(II) and zinc (II) complexes of l-amino-3-methylthiopropanephosphonic acid (MetP) and α-AlaP have been determined pH-metrically at 25°C at an ionic strength of 0.2 mol dm−3 (KC1).
Abstract: The stoichiometrics and stability constants of the nickel(II), copper(II) and zinc(II) complexes of l-amino-3-methylthiopropanephosphonic acid (MetP) and 1-amino-ethanephosphonic acid (a-AlaP) have been determined pH-metrically at 25°C at an ionic strength of 0.2 mol dm−3 (KC1). From the stability data and the absorption spectra of the complexes it has been established that simple aminophosphonic acids coordinate to the nickel(II) and copper(II) ions forming chelate complexes in which the metal binding mode is bidentate with the {NH2, PO3 2-} donor set. 31P and 1H NMR measurements showed that MetP and α-AlaP exhibit similar properties in the presence of zinc(II) ions, but the ligand reacts to form a cyclic phosphonoamidate in neutral and slightly alkaline solution in the Zn(II)-α-AlaP system and at slightly acidic conditions in the Zn(II)-MetP system. This difference reveals that the latter ligand at pH > 7 prefers Zn(II) coordination involving all possible (amino, phosphonate and thioether sulfu...
TL;DR: In this paper, the structure of [Mn(H2O)2(ac-O) 2(2,4′-bipy)2] has been determined by single crystal X-ray methods; the complex crystallizes in the monoclinic system, space group P21/c.
Abstract: The title complex [Mn(H2O)2(ac-O)2(2,4′-bipy)2] (1) (ac = CH3COO−, 2,4′-bipy = 2,4′-bipyridyl) has been synthesized and characterized by elemental and thermal analysis, IR, magnetic and conductivity studies. The structure of [Mn(H2O)2(ac-O)2(2,4′-bipy)2] has been determined by single crystal X-ray methods; the complex crystallizes in the monoclinic system, space group P21/c with Z = 2, a = 8.035(1), b = 5.660(1), c = 26.130(5) A, β = 97.05(1)°, V = 1179.36 A3. The structure was solved by the Patterson method and refined by full-matrix least-squares techniques using F 2 values to conventional R = 0.050 for 2322 independent reflections with F 0 > 4[sgrave](F 0). The central Mn atom lies on a centre of symmetry and is six-coordinated to two CH3COO− groups, two water molecules and two bipyridyl groups.
TL;DR: In this article, the structures of two complexes of neodymium(III) with pvndine-2.6-dicarboxvlic acid of formula (NH4), [Nd(C7H3NO4)3]-7H2O (1) and [NH4[Nd3[Nc7H 3NO4]5 8H 2O]-5 H2O(2) have been determined by X-ray diffraction.
Abstract: The structures of two complexes of neodymium(III) with pvndine-2.6-dicarboxvlic acid of formula (NH4), [Nd(C7H3NO4)3]-7H2O (1) and (NH4)[Nd3(C7H3NO4)5 8H2O]-5H2O (2) have been determined by X-ray diffraction. Crystals of 1 are monoclinic, P21/c, a = 17.925(4). b = 10.198(2), c = 18.707(4) A, β = 112.22(3)°. Z = 4. Crystals of 2 are monoclinic C2/c, a = 22.205(4), b = 13.774(3), c = 17.783(4) A, β = 112.55(3)°, Z = 4. Both structures were solved by the heavy-atom method and refined to R = 0.032 for 7568 reflections (1) and 0.030 for 3267 reflections (2). The water molecules and NH+ 4 groups in both crystals participate in a network of hydrogen bonds.
TL;DR: In this article, the stochastic properties of 1:1 and 2:1 (metal/ligand) complexes with dibenzo2-4-crown-8 in binary nitromethane-acetonitrile mixtures were investigated.
Abstract: 7Li, 23Na and 13C NMR measurements were used to study the stoichiometry and stability of Li+ and Na+ complexes with dibenzo2–4–crown–8 in binary nitromethane‐acetonitrile mixtures. The resulting chemical shift-mol ratio data clearly reveal the formation of both 1:1 and 2:1 (metal/ligand) complexes in solution. Formation of the two adducts in nitromethane and acetonitrile solutions was further supported by monitoring the molar conductance of Li+ and Na+ solutions as a function of macrocycle/metal ion mol ratio. Stepwise formation constants of the 1:1 and 2:1 complexes were evaluated from computer fitting of the NMR mol ratio data to equations which relate observed metal ion chemical shifts to formation constants. In all solvent systems, sodium forms more stable complexes with the crown ether than lithium. There is an inverse linear relationship between the logarithms of the stability constants and the mol fraction of acetonitrile in the solvent mixtures.
TL;DR: In this article, the complexes of formulas [Ln(e-cl)8] (F3C-SO3)3 (Ln = La-Eu) and [ln(∊−cl)7] (f3c-so3) 3 (ln = Gd, Tb, Dy, Yb, Lu, ∊‐cl = ∊−caprolactam) were synthesized and characterized by elemental analysis, infrared spectroscopy, visible absorption spectra of the Nd compound and emission spectra
Abstract: Complexes of formulas [Ln(e-cl)8] (F3C-SO3)3 (Ln = La-Eu) and [Ln(∊‐cl)7] (F3C-SO3)3 (Ln = Gd, Tb, Dy, Yb, Lu, ∊‐cl = ∊‐caprolactam) were synthesized and characterized by elemental analysis, infrared spectroscopy, visible absorption spectroscopy of the Nd compound and emission spectroscopy of the Eu compound and the Gd compound, doped with Eu. IR experimental data suggest that the e-caprolactams are bonded to the central ions through the carbonyl oxygen and that the anions are not coordinated. The parameters calculated from the visible absorption spectrum of the Nd compound suggest electrostatic metal-ligand bonds. The emission spectrum of the europium compound suggests a D2d distorted towards C2v symmetry. X-ray single crystal analysis of the Pr compound shows that the anions are not coordinated and that the coordination polyhedron around the Pr3+ion has a slightly distorted D2d (dodecahedral) symmetry.
TL;DR: In this paper, the absorption spectrum of the reaction solution immediately after the disappearance of the starting complex was different from that of cis-[CoBr(NH3)(en)2]2+ but was quite similar to that of [Co(H2O)(OH)2Co(en) 2 ].
Abstract: The production of cis-[CoBr(NH3)(en)2]Br2 by reaction of [Co(H2O)2{(OH)2Co(en)2}2](SO4)2 with ammonium bromide in water was investigated. The reaction seems to proceed through the intermediate, [Co(H2O)(OH)(en)2]2+, and then convert to the product, cis-[CoBr(NH3)(en)2]2+. This is supported by the observation that the absorption spectrum of the reaction solution immediately after the disappearance of the starting complex was different from that of cis-[CoBr(NH3)(en)2]2+ but was quite similar to that of [Co(H2O)(OH)(en)2]2+. In order to confirm this reaction pathway, cis-[Co(H2O)(OH)(en)2]Br2 was prepared and reacted with ammonium bromide producing the expected complex, cis-[CoBr(NH3)(en)2]Br2.
TL;DR: In this paper, a chromatographic resolution of [Si(bpy)3]4+ (bpy = 2,2′-bipyridine) was achieved using an SP-Sephadex C-25 column as an adsorbent and a 016M aqueous solution of sodium (2R,3R)-(-)-O,O,Dibenzoyltartrate as an eluent.
Abstract: [Si(bpy)3]4+ (bpy = 2,2′-bipyridine), synthesized from Sil4 and 2′-bipyndine was optically resolved by a chromatographic method using an SP-Sephadex C-25 column as an adsorbent and a 016M aqueous solution of sodium (2R,3R)-(-)-O,O′-dibenzoyltartrate as an eluent The optical isomers were characterized by measurement of their electronic absorption, circular dichroism, and 1H NMR spectra The chromatographic resolution of [SKbpyb]4+ was also attempted with an aqueous solution of potassium [(2R,3R)-(+)-tartrato]antimonate(III) sodium (2R,3R)-(+)-hydrogentartrate, and sodium (2R,3R)-(+)-tartrate as eluents Force-field calculations were used to elucidate the chromatographic elution mechanism [Si(OH)2(bpy)2]I2was also synthesized from Sil4 and 2′,-bipyridine The optical resolution of this complex was achieved with sodium [(2R,3R)-(+)-tartrato]antimonate(III)
TL;DR: The structure of blue, monoclinic (C2) crystals of trans-aquabis(L-N, N-dimethylalaninato-)copper(II) hexahydrate was determined by X-ray diffraction methods and refined to R = 0.026 as mentioned in this paper.
Abstract: The structure of blue, monoclinic (C2) crystals of trans-aquabis(L-N, N-dimethylalaninato-)copper(II) hexahydrate was determined by X-ray diffraction methods and refined to R = 0.026. The structure...
TL;DR: In this paper, the interaction of SeCN− with a new gold-based antiarthritic drug auranofin (Et3PAuSATg), where SATg− = 2, 3, 4, 6-tetra-O-acetyl-l-thio-β-D-glucopyranosato-S, was studied by 13C and 31P NMR spectroscopy.
Abstract: The interaction of SeCN− with a new gold-based antiarthritic drug auranofin (Et3PAuSATg, where SATg− = 2, 3, 4, 6-tetra-O-acetyl-l-thio-β-D-glucopyranosato-S) in aqueous methanol has been studied by 13C and 31P NMR spectroscopy. It is observed that SeCN−releases bom ligands (i. e., SATg− and Et3P) to form [ATgS-Au-CN]− and [Et3P-Au-SeCN]. These newly generated species undergo further disproportionation and decomposition to generate species such as [(Et3P)2Au]+, [Au(CN)2]−, Et3PO and metallic selenium. The formation of [(Et3P)2Au]+ and [Au(CN)2]− is found to be much faster for Et3PAuNO3 than for Et3PAuSATg when reacted wim SeCN−. Exchange between unlabelled CN− of Au(CN)2 − and labelled Se13CN− was observed without selenium being precipitated from Se13CN−.
TL;DR: In this paper, the vibrational spectra are discussed in detail and a full assignment in the spectral range between 1700-200 cm−1 is proposed, some comparisons with related species are made.
Abstract: Oxovanadium(IV) and oxovanadium(V) complexes with the stoichiometries VO(NOQ)2 and VO(NOQ)2OH respectively, containing the N-oxide of 8-hydroxyquinoline (NOQH) as a ligand were synthesized and characterized by elemental analysis, infrared. Raman and electronic spectroscopy. The vibrational spectra are discussed in detail and a full assignment in the spectral range between 1700-200 cm−1 is proposed. Some comparisons with related species are made.