scholarly journals Dinuclear Lanthanide(III) Complexes from the Use of Methyl 2-Pyridyl Ketoxime: Synthetic, Structural, and Physical Studies

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1622
Author(s):  
Christina D. Polyzou ◽  
Helen Nikolaou ◽  
Catherine P. Raptopoulou ◽  
Konstantis F. Konidaris ◽  
Vlasoula Bekiari ◽  
...  
Keyword(s):  
Metal Ion ◽  
Structural Characteristics ◽  
Exchange Interactions ◽  
X Ray ◽  
X Ray Crystallography ◽  
Elemental Analyses ◽  
3D Architecture ◽  
Inorganic Ligands ◽  
Hydrolysis Of ◽  
The Eu

The first use of methyl 2-pyridyl ketoxime (mepaoH) in homometallic lanthanide(III) [Ln(III)] chemistry is described. The 1:2 reactions of Ln(NO3)3·nH2O (Ln = Nd, Eu, Gd, Tb, Dy; n = 5, 6) and mepaoH in MeCN have provided access to complexes [Ln2(O2CMe)4(NO3)2(mepaoH)2] (Ln = Nd, 1; Ln = Eu, 2; Ln = Gd, 3; Ln = Tb, 4; Ln = Dy, 5); the acetato ligands derive from the LnIII—mediated hydrolysis of MeCN. The 1:1 and 1:2 reactions between Dy(O2CMe)3·4H2O and mepaoH in MeOH/MeCN led to the all-acetato complex [Dy2(O2CMe)6(mepaoH)2] (6). Treatment of 6 with one equivalent of HNO3 gave 5. The structures of 1, 5, and 6 were solved by single-crystal X-ray crystallography. Elemental analyses and IR spectroscopy provide strong evidence that 2–4 display similar structural characteristics with 1 and 5. The structures of 1–5 consist of dinuclear molecules in which the two LnIII centers are bridged by two bidentate bridging (η1:η1:μ2) and two chelating-bridging (η1:η2:μ2) acetate groups. The LnIII atoms are each chelated by a N,N’-bidentate mepaoH ligand and a near-symmetrical bidentate nitrato group. The molecular structure of 6 is similar to that of 5, the main difference being the presence of two chelating acetato groups in the former instead of the two chelating nitrato groups in the latter. The geometry of the 9-coordinate LnIII centers in 1, 5 and 6 can be best described as a muffin-type (MFF-9). The 3D lattices of the isomorphous 1 and 5 are built through H-bonding, π⋯π stacking and C-H⋯π interactions, while the 3D architecture of 6 is stabilized by H bonds. The IR spectra of the complexes are discussed in terms of the coordination modes of the organic and inorganic ligands involved. The Eu(III) complex 2 displays a red, metal-ion centered emission in the solid state; the TbIII atom in solid 4 emits light in the same region with the ligand. Magnetic susceptibility studies in the 2.0–300 K range reveal weak antiferromagnetic intramolecular GdIII…GdIII exchange interactions in 3; the J value is −0.09(1) cm−1 based on the spin Hamiltonian Ĥ = −J(ŜGd1·ŜGd2).

Preparation and structural analysis of (±)-threo-ritalinic acid

2013 ◽  
Vol 69 (11) ◽  
pp. 1225-1228 ◽  
Author(s):  
Sara Wyss ◽  
Irmgard A. Werner ◽  
W. Bernd Schweizer ◽  
Simon M. Ametamey ◽  
Selena Milicevic Sephton
Keyword(s):  
Methyl Ester ◽  
Free Acid ◽  
Nmr Analysis ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ph Values ◽  
Ritalinic Acid ◽  
Methyl Phenidate ◽  
Hydrolysis Of

Hydrolysis of the methyl ester (±)-threo-methyl phenidate afforded the free acid in 40% yield,viz.(±)-threo-ritalinic acid, C13H17NO2. Hydrolysis and subsequent crystallization were accomplished at pH values between 5 and 7 to yield colourless prisms which were analysed by X-ray crystallography. Crystals of (±)-threo-ritalinic acid belong to theP21/nspace group and form intermolecular hydrogen bonds. An antiperiplanar disposition of the H atoms of the (HOOC—)CH—CHpygroup (py is pyridine) was found in both the solid (diffraction analysis) and solution state (NMR analysis). It was also determined that (±)-threo-ritalinic acid conforms to the minimization of negativegauche+–gauche−interactions.

scholarly journals Simple Methylcadmium Alkoxides

2007 ◽  
Vol 62 (10) ◽  
pp. 1339-1342 ◽  
Author(s):  
Surajit Jana ◽  
Tania Pape ◽  
Norbert W. Mitzel
Keyword(s):  
Mass Spectrometry ◽  
Solid State ◽  
Molecular Formula ◽  
Equimolar Ratio ◽  
X Ray ◽  
X Ray Crystallography ◽  
Elemental Analyses ◽  
Solid State Structures ◽  
Structural Aspects ◽  
C Nmr

The reaction of dimethylcadmium with alcohols R-OH in equimolar ratio leads to the formation of tetrameric methylcadmium alkoxides with molecular formula [(MeCd)4 (OR)4] [R = Me (1), Et (2) and iPr (3)]. These compounds have been characterised by 1H, 13C NMR and IR spectroscopy, by mass spectrometry, elemental analyses and by X-ray crystallography (for 2 and 3). The solid state structures show distorted cubane-type aggregates with Cd4O4 cores. The structural aspects and the spectroscopic characterisations of these compounds are discussed.

scholarly journals Mechanism of IPPase shown by high resolution Neutron and X-ray crystallography

2014 ◽  
Vol 70 (a1) ◽  
pp. C1211-C1211
Author(s):  
Joseph Ng ◽  
Ronny Hughes ◽  
Michelle Morris ◽  
Leighton Coates ◽  
Matthew Blakeley ◽  
...  
Keyword(s):  
High Resolution ◽  
Active Site ◽  
Inorganic Pyrophosphatase ◽  
Inorganic Pyrophosphate ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cellular Processes ◽  
Crystallographic Structures ◽  
Hydrolysis Of ◽  
Low Energy Conformations

Soluble inorganic pyrophosphatase (IPPase) catalyzes the hydrolysis of inorganic pyrophosphate (PPi) to form orthophosphate (Pi). The action of this enzyme shifts the overall equilibrium in favor of synthesis during a number of ATP-dependent cellular processes such as in the polymerization of nucleic acids, production of coenzymes and proteins and sulfate assimilation pathways. Two Neutron crystallographic (2.10-2.50Å) and five high-resolution X-ray (0.99Å-1.92Å) structures of the archaeal IPPase from Thermococcus thioreducens have been determined under both cryo and room temperatures. The structures determined include the recombinant IPPase bound to Mg+2, Ca+2, Br-, SO2-2 or PO4-2 involving those with non-hydrolyzed and hydrolyzed pyrophosphate complexes. All the crystallographic structures provide snapshots of the active site corresponding to different stages of the hydrolysis of inorganic pyrophosphate. As a result, a structure-based model of IPPase catalysis is devised showing the enzyme's low-energy conformations, hydration states, movements and nucleophile generation within the active site.

scholarly journals An Unexpected Trinuclear Cobalt(II) Complex Based on a Half-Salamo-Like Ligand: Synthesis, Crystal Structure, Hirshfeld Surface Analysis, Antimicrobial and Fluorescent Properties

Crystals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 408 ◽  
Author(s):  
Ruo-Yan Li ◽  
Xiao-Xin An ◽  
Juan-Li Wu ◽  
You-Peng Zhang ◽  
Wen-Kui Dong
Keyword(s):  
Crystal Structure ◽  
Surface Analysis ◽  
Three Dimensional ◽  
Antimicrobial Activities ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Fluorescent Properties ◽  
X Ray ◽  
X Ray Crystallography ◽  
Elemental Analyses

An unexpected trinuclear Co(II) complex, [Co3(L2)2(μ-OAc)2(CH3OH)2]·2CH3OH (H2L2 = 4,4′-dibromo-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) constructed from a half-Salamo-based ligand (HL1 = 2-[O-(1-ethyloxyamide)]oxime-4-bromophenol) and Co(OAc)2·4H2O, has been synthesized and characterized by elemental analyses, infrared spectra (IR), UV-Vis spectra, X-ray crystallography and Hirshfeld surface analysis. The Co(II) complex contains three Co(II) atoms, two completely deprotonated (L2)2− units, two bridged acetate molecules, two coordinated methanol molecules and two crystalline methanol molecules, and finally, a three-dimensional supramolecular structure with infinite extension was formed. Interestingly, during the formation of the Co(II) complex, the ligand changed from half-Salamo-like to a symmetrical single Salamo-like ligand due to the bonding interactions of the molecules. In addition, the antimicrobial activities of HL1 and its Co(II) complex were also investigated.

Flexible N-Donor Ligands Direct the Structural Characteristics of CoII Complexes: Syntheses, Structures, and Magnetic Properties

2019 ◽  
Vol 72 (5) ◽  
pp. 341 ◽  
Author(s):  
Yu-Ting Yang ◽  
Chang-Zheng Tu ◽  
Xiao-Lin Xu ◽  
Li-Li Xu ◽  
Bang-Ling Yan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Coordination Polymers ◽  
Structural Characteristics ◽  
Donor Ligands ◽  
X Ray Diffraction ◽  
Thermal Stabilities ◽  
Ancillary Ligands ◽  
X Ray ◽  
Elemental Analyses ◽  
Bilayered Structure

Solvothermal reactions of 3,3′,5,5′-biphenyltetracarboxylic acid (H4BPTC) and cobalt(ii) ions in the presence of two different flexible N-donor ancillary ligands afford two novel coordination polymers, {[Co(BPTC)0.5(bix)]·H2O}n (1), {[Co(BPTC)0.5(bpp)]·3H2O}n (2) (bix=1,4-bis(imidazol-1-ylmethyl)benzene; bpp=1,3-bis(4-pyridyl)propane). Their structures have been determined by elemental analyses, IR spectra, single-crystal X-ray diffraction analyses, and powder X-ray diffraction. The pillared layered framework of 1 can be simplified to a (4,6)-connected net with a Schläfli symbol of (44·62)(44·69·82). Complex 2 manifests a bilayered structure, and can be simplified to a (4,4)-connected net with a Schläfli symbol of (55·8)(54·62). The thermal stabilities of both complexes and the magnetic behaviours of 1 are also discussed.

Die oxidative Addition von NickeI(0)-KompIexen an Kohlenstoff-Kohlenstoff-Bindungen im Cyclobutadien. Zur Frage der Überführbarkeit von Cyclobutadien-Nickel(O)-Komplexen in Nickelaringe / Oxidative Addition of Nickel(O) Complexes to Carbon-Carbon Bonds in Cyclobutadiene. The Question of the Interconvertibility of Cyclobutadiene-nickel(O) Complexes and the Nickelaring Systems

1985 ◽  
Vol 40 (5) ◽  
pp. 624-635 ◽  
Author(s):  
John J. Eisch ◽  
Andrzej M. Piotrowski ◽  
Allen A. Aradi ◽  
Carl Krüger ◽  
Maria J. Romão
Keyword(s):  
Spectral Data ◽  
Structure Determination ◽  
Oxidative Addition ◽  
Subsequent Treatment ◽  
X Ray ◽  
X Ray Crystallography ◽  
Carbon Carbon Bonds ◽  
Elemental Analyses ◽  
Carbon Bonds

Abstract Bis(triethylphosphine)(η4-tetraphenylcyclobutadiene)nickel (4) was synthesized by the reduction of (η4-tetraphenylcyclobutadiene)nickel(II)bromide (3) with t-butyllithium in the presence of Et3P, and its structure was determined by X-ray crystallography. Furthermore, its reactivity towards CO, CH3CO2H, PhC≡CPh, LiAlH4 and O2 were investigated. 1,1-Bis(triethylphos-phine)-2,3,4,5-tetraphenylnickelole (14) was synthesized from (E,E)-1,4-dilithio-1,2,3,4-tetraphenyl-1,3-butadiene (15) and bis(triethylphosphine)nickel(II)bromide. Since the resulting crystals of the nickelole were not suitable for X-ray structure determination, the compound was characterized by elemental analyses, spectral data and carbonylation to yield tetraphenylcyclo-pentadienone (6).Analogous reductions of (η4 -tetraphenylcyclobutadiene)nickel(II)bromide (3) in the presence of Ph3P or Ph2PCH2CH2PPh2 , followed by carbonylation, led to 6 in 40% yield, demonstrating that about half of the cyclobutadiene rings in 3 undergo cleavage upon reduction to give the nickelole.Reactions of the dilithium reagent 15 with NiBr2 complexed with Me2PCH2CH2PMe2 ,Ph3P or Et2PCH2CH2PEt2 , led to the formation of thermolabile nickeloles, as demonstrated by carbonylàtion which yielded 6. Warming of the nickeloles and subsequent treatment with CH3CO2H led to the formation of 1,2,3,4,5,6,7,8-octaphenyl-1,3,5,7-octatetraene (8) and, in one case, octaphenyl-cyclooctatetraene (5).The relevance of these findings to the mechanism of the Reppe nickel-catalyzed oligomerization of alkynes is discussed.

Preparation and characterization of Tl(1,2-C2H4Cl2)B(OTeF5)4: a metal complex of a least coordinating solvent and a least coordinating anion

1992 ◽  
Vol 70 (3) ◽  
pp. 726-731 ◽  
Author(s):  
Paul K. Hurlburt ◽  
Oren P. Anderson ◽  
Steven H. Strauss
Keyword(s):  
Metal Ion ◽  
Chelate Ring ◽  
Ion Solvation ◽  
Crystalline Compound ◽  
Triclinic Space Group ◽  
X Ray ◽  
X Ray Crystallography ◽  
Solid Salt ◽  
Solvent Metal

Addition of B(OTeF5)3 to TIOTeF5 in the weakly coordinating solvents dichloromethane, 1,2-dichloroethane, and 1,1,2-trichlorotrifluoroethane produces solutions of M(solv)x+B(OTeF5)4−. When the solvent was 1,2-dichloroethane, the crystalline compound Tl(1,2-C2H4Cl2)B(OTeF5)4 was isolated and studied by X-ray crystallography: triclinic, space group [Formula: see text], a = 9.221 (4), b = 11.396(5), c = 12.538 (4) Å, α = 110.75 (3)°, β = 101.72(3)°, γ = 99.74 (3)°, Z = 2, T = −116 °C. The Tl(1,2-C2H4Cl2)+ cation contains a five-membered chelate ring with Tl—Cl distances of 3.138 (4) and 3.179 (3) Å. The metal ion is weakly bonded to four B(OTeF5)4− counterions, with nine Tl—F interactions that range from 2.950 (5) to 3.981 (8) Å. When the solvent is dichloromethane or 1,1,2-trichlorotrifluoroethane, only the unsolvated solid salt TlB(OTeF5)4 can be isolated by crystallization. This salt is thermally unstable, slowly forming TlOTeF5 and volatile B(OTeF5)3. Keywords: noncoordinating anion, noncoordinating solvent, metal ion solvation.

New homodinuclear tris(3-alkylpyrazolyl)borate complexes of CoIIand NiIIwith a tetraacetylethane dianion as a bridging ligand

2016 ◽  
Vol 72 (11) ◽  
pp. 777-785
Author(s):  
Elena A. Mikhalyova ◽  
Swiatoslaw Trofimenko ◽  
Matthias Zeller ◽  
Anthony W. Addison ◽  
Vitaly V. Pavlishchuk
Keyword(s):  
Metal Ions ◽  
Coordination Polymers ◽  
Metal Ion ◽  
Molecular Structures ◽  
Polynuclear Complexes ◽  
X Ray ◽  
X Ray Crystallography ◽  
Coordination Sites ◽  
Borate Complexes ◽  
Capping Ligands

Polynuclear complexes and coordination polymers of 3dmetals have attracted significant interest evoked by a number of their unique properties. One of the most common approaches to the directed synthesis of coordination polymers is the linking of pre-prepared discrete coordination units by polydentate ligands. The formation of polynuclear complexes is usually a spontaneous process and precise prediction of the products of such reactions is virtually impossible in most cases. Tris(pyrazolyl)borates (Tp) act as tripodal `capping' ligands which form stable complexes with 3dmetal ions. In such 1:1 compounds, three metal-ion coordination sites are occupied by N atoms from a Tp anion. This limits the number of remaining coordination sites, and thus the number of additional ligands which may coordinate, and opens an attractive approach for the directed design of desirable structures by exploiting ligands with appropriate composition and topology. In the present study, Tp anions with neopentyl [TpNp, tris(3-neopentylpyrazolyl)borate] and cyclohexyl [TpCy, tris(3-cyclohexylpyrazolyl)borate] substituents were used as `capping' ligands and the dianion of tetraacetylethane (3,4-diacetylhexa-2,4-diene-2,5-diolate, tae2−) was employed as a bridge. The dinuclear complexes (μ-3,4-diacetylhexa-2,4-diene-2,5-diolato-κ4O2,O3:O4,O5)bis{[tris(3-cyclohexyl-1H-pyrazol-1-yl-κN2)borato]cobalt(II)} acetonitrile disolvate, [Co2(C27H40BN6)2(C10H12O4)]·2CH3CN, (I)·2CH3CN, and (μ-3,4-diacetylhexa-2,4-diene-2,5-diolato-κ4O2,O3:O4,O5)bis{[tris(3-neopentyl-1H-pyrazol-1-yl-κN2)borato]nickel(II)}, [Ni2(C24H40BN6)2(C10H12O4)], (II), were synthesized by the reaction of the mononuclear complexes TpCyCoCl or TpNpNiCl with H2tae (3,4-diacetylhexane-2,5-dione or tetraacetylethane) in the presence of NEt3as base. Compounds (I) and (II) were characterized by mass spectrometry, elemental analysis, and X-ray crystallography. They possess similar molecular structures, X-ray diffraction revealing them to be dinuclear in nature and composed of discrete Tp–Munits in which two metal ions are linked by a tae2−dianion. Each metal ion possesses a five-coordinate square-pyramidal environment. The interplanar angles between the acetylacetonate fragments are significantly smaller than the near-90° values commonly observed.

Open-Framework Solids with Diamond-Like Structures Prepared from Clusters and Metal-Organic Building Blocks

1994 ◽  
Vol 371 ◽  
Author(s):  
Omar M. Yaghi ◽  
D. A. Richardson ◽  
G. Li ◽  
C. E. Davis ◽  
T. L. Groy
Keyword(s):  
Metal Ion ◽  
Building Blocks ◽  
Diamond Structure ◽  
Tetrahedral Cluster ◽  
X Ray ◽  
Open Framework ◽  
X Ray Crystallography ◽  
Metal Organic ◽  
Channel Systems ◽  
Cu And Zn

AbstractThe tetrahedral cluster Ge4S104- and the rodlike ligand 4,4′-bipyridine are utilized in addition copolymerization reactions with the metal (II) ions of Mn, Fe, Co, Cu, and Zn in the preparation of 3-D open-framework solids, MxCol-xGe4S10-2(CH3)4N (x = 0.86, M = Mn; x = 1, M = Mn, Fe, Co, and Zn), 1, and Cu(4,4′-bpy)2. PF6, 2, having diamond-like structures. These structures are viewed in terms of the cubic diamond structure, where the carbon atoms have been replaced by either a cluster or a metal ion and the C-C bond by a sulfide or the 4,4′-bpy. These compounds have been fully characterized by single crystal x-ray crystallography and their composition was confirmed by elemental analysis; they contain 3-D channel systems where cations or anions reside to balance the charge on the framework.

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