Synthesis of [3-<Superscript>14</Superscript>C]-L-tryptophan and 5′-hydroxy-[3-<Superscript>14</Superscript>C]-L-tryptophan

The synthesis of selectively labeled [3-¹⁴C]-L-tryptophan and its derivative 5′-hydroxy-[3-¹⁴C]-L-tryptophan using chemical and multienzymatic methods is reported. The key intermediate for this synthesis, [3-¹⁴C]-DL-alanine was obtained from ¹⁴CH₃I as a result of its condensation with N-(diphenylmethylene)glycine tert-butyl ester. Next, the mixture containing [3-¹⁴C]-DL-alanine, indole or 5-hydroxyindole has been converted to [3-¹⁴C]-L-tryptophan or 5′-hydroxy-[3-¹⁴C]-L-tryptophan, respectively, in a one-pot multienzymatic reaction using four enzymes: D-amino acid oxidase, catalase, glutamic-pyruvic transaminase and tryptophanase.     

A theoretical study on the dynamics of the gas phase reaction of NH<Subscript>2</Subscript>(<Superscript>2</Superscript>B<Subscript>1</Subscript>) with HO<Subscript>2</Subscript>(<Superscript>2</Superscript>A″)

Quasi-classical trajectory calculations and stochastic one-dimensional chemical master equation simulation methods are used to study the dynamics of the reaction of amidogen radical [NH₂(²B₁)] with hydroperoxyl radical [HO₂(²A″)] on the lowest singlet electronic state. The title complex reaction takes place on a multi-well multichannel potential energy surface consisting of three deep potential wells and one van der Waals complex. In quasi-classical trajectory calculations a new analytical potential energy surface based on CCSD(T)/aug-cc-pVTZ//MPW1K/6-31+G(d,p) ab initio method was driven and used to study the dynamics of the title reaction. In quasi-classical trajectory calculations, the reactive cross sections and reaction probabilities are determined for 200–2000 K relative translational energies to calculate the rate constants. The same ab initio method was used to have the necessary data for solving the one-dimensional chemical master equation to calculate the rate constants of different channels. In solving the master equation, the Lennard-Jones potential model was used to form the collision between the collider gases. The fractional populations of different intermediates and products in the early stages of the reaction were examined to determine the role of the energized intermediates and the van der Waals complex on the dynamics of the title reaction. Although the calculated total rate constants from both methods are in good agreement with the reported experimental values in the literature, the quasi-classical trajectory simulation predicts the formation of NH₂O + OH as the major channel in the title reaction in accordance with the previous studies (Sumathi and Peyerimhoff, Chem. Phys. Lett., 263:742–748, 1996), while the stochastic master equation simulation predicts the formation of HNO + H₂O as the major products.     

Structural investigation of salts containing ions [Pd(NH<Subscript>3</Subscript>)<Subscript>4</Subscript>]<Superscript>2+</Superscript> and [IrF<Subscript>6</Subscript>]<Superscript>2–</Superscript>

Double complex salts (DCS) α-[Pd(NH₃)₄][IrF₆]·H₂O (P2₁/m, a = 6.3181(3) Å, b = 10.8718(5) Å, с = 7.4526(4) Å, β = 103.568(2)°), β-[Pd(NH₃)₄][IrF₆]·H₂O (P2₁/с, a = 8.5773(3) Å, b = 10.8791(4) Å, с = = 12.6741(3) Å, β = 122.497(2)°), [Pd(NH₃)₄]₃[IrF₆]₂Cl₂·H₂O (P-1, a = 7.6080(2) Å, b = 7.6274(2) Å, с = 11.8070(3) Å, β = 122.497(2)°), and [Pd(NH₃)₄]₂[IrF₆]NO₃ (Fm-3m, a = 11.21210(10) Å) have been synthesized and structurally characterized for the first time. The existence of polymorphs for the DCS has been revealed. The influence of the chemical composition of the initial reagents on the reaction course and, respectively, the products, has been demonstrated. A hypothesis on the influence of the second coordination sphere on the formation of one or the other polymorph of the DCS has been suggested. It has been shown that the series α-[Pd(NH₃)₄][МF₆]·H₂O (M = Pt, Pd) exhibits isostructurality.     

Synthesis and structure of the complex [Mo<Subscript>3</Subscript>(μ<Subscript>3</Subscript>-S)(μ<Subscript>2</Subscript>-S<Subscript>2</Subscript>)<Subscript>3</Subscript>(Et<Subscript>2</Subscript>NCS<Subscript>2</Subscript>)<Subscript>3</Subscript>]I

The structure of tri-μ₂-disulfido-μ₃-thiotris(diethyldithiocarbamato)-S,S′-triangle-trimolybdenum iodide [Mo₃(μ₃-S)(μ₂-S₂)₃(Et₂NCS₂)₃]I was determined. The compound was characterized by differential thermal analysis and IR, Raman, and X-ray electronic spectroscopy.     

Blue and green upconversion luminescence modification of Tb<Superscript>3+</Superscript>–Yb<Superscript>3+</Superscript> co-doped Ca<Subscript>5</Subscript>(PO<Subscript>4</Subscript>)<Subscript>3</Subscript>F inverse opal

Tb³⁺–Yb³⁺ co-doped Ca₅(PO₄)₃F inverse opal photonic crystals were prepared by a self-assembly technique in combination with a sol–gel method. Upconversion luminescence characteristics of the inverse opals were investigated. The results indicate that photonic band gap has a significant effect on upconversion luminescence of Tb³⁺–Yb³⁺ co-doped Ca₅(PO₄)₃F inverse opal. Significant inhibition of the green or blue upconversion luminescence was inspected if the photonic band gap overlapped with the emission band of Tb³⁺ ions.     

Synthesis of the [<Superscript>2</Superscript>H,<Superscript>15</Superscript>N]-labeled antiviral drug “triazavirine”

Selective methods for the incorporation of stable isotopes ¹⁵N and ²H into the structure of antiviral medicine “triazavirine” 1 were developed. The synthesized isotopically modified “triazavirine” 1– ² H ₃ , ¹⁵ N ₃ contained the labeled atoms in both the azole and the azine rings. ¹³C and ¹⁵N NMR spectra of the isotope-containing sample 1– ² H ₃ , ¹⁵ N ₃ were thoroughly analyzed.     

Mercury complex [(HOCH<Subscript>2</Subscript>)<Subscript>3</Subscript>CNH<Subscript>3</Subscript>]<Stack><Subscript>2</Subscript><Superscript>+</Superscript></Stack> [HgI<Subscript>4</Subscript>]<Superscript>2−</Superscript>: Synthesis and structure

The complex [(HOCH₂)₃CNH₃] ₂ ⁺ [HgI₄]^2? (I) was synthesized by reacting (trioxymethyl)methylammonium iodide with mercury dioide (2: 1 mol/mol) in acetone. X-ray crystallography shows that the complex consists of two types of crystallographically independent [(HOCH₂)₃CNH₃]⁺ cations and tetrahedral anions [HgI₄]^2? (IHgI, 106.49(2)°–113.99(4)°; Hg-I, 2.7849(8)-2.8105(8) Å. [(HOCH₂)₃CNH₃]⁺ cations are linked via hydrogen bonds O…H-N and O-H…N (O…N, 2.84–2.92 Å) to form polymer chains, which are cross-linked with one another via anions (I…H, 2.81, 2.82 Å).     

Influence of the temperature and cation nature on the EPR spectra of salts with the [Ni<Superscript>III</Superscript>(η<Superscript>5</Superscript>-1,2-B<Subscript>9</Subscript>C<Subscript>2</Subscript>H<Subscript>11</Subscript>)<Subscript>2</Subscript>]- anion

The influence of specific features of the structure and nature of the cations (Ph₄P⁺, H(Phen)⁺, Cs⁺, and (CH₃)₄N⁺) on the ERP spectra of the nickel ions in salts with the dicarbollylnickelate anion [Ni(B₉C₂H₁₁)₂]⁻ is studied. It is shown that the change in the cation type in these compounds results in the electron density redistribution, which affects the change in the main and average values of the g factor. The g _av value increases over that observed in frozen solutions upon the localization of the positive charge of the cation on one atom and in the absence of the screening effect of the solvent and large functional groups of the cation. The exception is the compound (Ph₄P⁺)NiCb₂⁻ (Cb is B₉C₂H₁₁) with solvated CCl₄ molecules. For all compounds studied, the temperature dependence of the linewidths in the EPR spectra is described by the equation ΔH = αT + βT⁷ with different α and β values and is defined by the temperature dependence of the relaxation process caused by the Raman interaction.     

Syntheses and structures of six-coordinate K[Ga<Superscript>III</Superscript>(Cydta)] · 2H<Subscript>2</Subscript>O and K[Ga<Superscript>III</Superscript>(Pdta)] · 3H<Subscript>2</Subscript>O complexes

The title complexes, K[Ga^III(Cydta)] · 2H₂O(Cydta = trans-1,2-cyclohexanediaminetetraacetic acid) and K[Ga^III(Pdta)] · 3H₂O (Pdta = propylenediaminetetraacetic acid), were prepared, and their structures were studied by IR spectra, elemental analyses, NMR spectra, and single-crystal X-ray diffraction techniques. In the K[Ga^III(Cydta)] · 2H₂O complex, the Ga³⁺ is six-coordinated by the Cydta ligand yielding an octahedral conformation, and the complex crystallizes in the monoclinic system with the P2₁/c space group. The crystal data are as follows: a = 16.5039(19), b = 13.1499(16), c = 8.5204(10) Å, β = 101.650(2)°, V = 1811.0(4) ų, Z = 4, ρ = 1.757 g/cm³, μ = 1.805 mm^?1, F(000) = 984, R = 0.0291, and wR = 0.0698 for 3713 observed reflections with I ≥ 2σ(I). In the K[Ga^III(Pdta)] · 3H₂O complex, the Ga³⁺ is also six-coordinated by the Pdta ligand yielding an almost standard octahedral conformation, and the complex crystallizes in the orthorhombic system with P2₁2₁2₁ space group. The crystal data are as follows: a = 8.8913(10), b = 11.6181(13), c = 17.0227(19) Å, V = 1758.4(3) ų, Z = 4, ρ = 1.757 g/cm³, μ = 1.862 mm^?1, F(000) = 952, R = 0.0288, and wR = 0.0724 for 3556 observed reflections with I ≥ 2σ(I).     

Structures of the complex ions [CuCl<Subscript>4</Subscript>]<Superscript>2−</Superscript> and [CuCl<Subscript>5</Subscript>]<Superscript>3−</Superscript>

The electronic structures of the complex ions [CuCl₄]^2? and [CuCl₅]^3? were analyzed in terms of the extended angular overlap model (AOM) with consideration to sd and pd mixing. The total antibonding orbital energies of these ions show no anomalies in the transition from a tetrahedron to a planar square [CuCl₄]^2? and from a trigonal bipyramid to a tetragonal pyramid [CuCl₅]^3?. Presumably, the existence of numerous intermediate forms of these complexes is mainly due to the packing effects rather than the electronic factors.     

Gas-phase observation of the heterolytic dissociation of negative ions into counter ions: Dissociation of [Cu phthalocyanine (SO<Subscript>3</Subscript>)<Subscript>4</Subscript>Na]<Superscript>3−</Superscript>.

Ion pair formation proceeding in solution at room-temperature, where it is driven by energies of solvation, has been observed in the gas-phase in the collision-induced dissociation of [Cu phthalocyanine (SO3)4Na]3- and [Cu phthalocyanine (SO3)4Na2]2- at low energies. The gas-phase observation of these charge separations into positive and negative ions, seemingly counter-intuitive, is favored sufficiently by thermodynamics to proceed at low collision energies. The combination of a high stability of the negative product anion against electron detachment and a low recombination energy of the departing positive counter ion appears to be the key requirement for such dissociations to proceed at low energies in the gas-phase.     

Study on the thermal behavior of the complexes of the type [PdX<Subscript>2</Subscript>(tdmPz)] (X = Cl<Superscript>−</Superscript>, Br<Superscript>−</Superscript>, I<Superscript>−</Superscript>, SCN<Superscript>−</Superscript>)

Four new mononuclear Pd(II) complexes of the type [PdX₂(tdmPz)] {X = Cl⁻ (1); Br⁻ (2); I⁻ (3); SCN⁻ (4); tdmPz = 1-thiocarbamoyl-3,5-dimethylpyrazole} have been synthesized and characterized by elemental analysis, IR spectroscopy, ¹H and ¹³C{¹H}-NMR experiments. The thermal behavior of the complexes 1–4 has been investigated by means of thermogravimetry (TG) and differential thermal analysis (DTA). From the initial decomposition temperatures, the thermal stability of the complexes can be ordered in the sequence: 3 < 4 ≡ 2 < 1. The final products of the thermal decompositions were characterized as metallic palladium by X-ray powder diffraction.     

Synthesis of diamantane via skeletal isomerization of hydrogenated cyclohepta-1,3,5-triene dimers in ionic liquid [Et<Subscript>3</Subscript>NH]<Superscript>+</Superscript> [Al<Subscript>2</Subscript>Cl<Subscript>7</Subscript>]<Superscript>–</Superscript>

Diamantane was synthesized in 91–97% yield by skeletal isomerization of a mixture of hydrogenated cyclohepta-1,3,5-triene dimers, pentacyclo[8.4.0.0^3,7.0^4,14.0^6,11]tetradecane and pentacyclo-[7.5.0.0^2,8.0^5,14.0^7,11]tetradecane, at a ratio of 3: 2 in the presence of ionic liquid [Et₃NH]⁺ [Al₂Cl₇]^–.     

Thermogravimetric analysis of wheatleyite Na<Subscript>2</Subscript>Cu<Superscript>2+</Superscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>·2H<Subscript>2</Subscript>O

Evidence for the existence of primitive life forms such as lichens and fungi can be based upon the formation of oxalates. These oxalates form as a film like deposit on rocks and other host matrices. The anhydrous oxalate mineral moolooite CuC₂O₄ as the natural copper(II) oxalate mineral is a classic example. Another example of a natural oxalate is the mineral wheatleyite Na₂Cu²⁺(C₂O₄)₂·2H₂O. High resolution thermogravimetry coupled to evolved gas mass spectrometry shows decomposition of wheatleyite at 255°C. Two higher temperature mass losses are observed at 324 and 349°C. Higher temperature mass losses are observed at 819, 833 and 857°C. These mass losses as confirmed by mass spectrometry are attributed to the decomposition of tennerite CuO. In comparison the thermal decomposition of moolooite takes place at 260°C. Evolved gas mass spectrometry for moolooite shows the gas lost at this temperature is carbon dioxide. No water evolution was observed, thus indicating the moolooite is the anhydrous copper(II) oxalate as compared to the synthetic compound which is the dihydrate.     

Crystal structure of a trinuclear Zn(II) complex: [Zn<Subscript>3</Subscript>L<Subscript>2</Subscript>(μ<Subscript>1,1</Subscript>-N<Subscript>3</Subscript>)<Subscript>2</Subscript>I<Subscript>2</Subscript>] [l = 2-[(3-dimethylaminopropylimino) methyl]-6-ethoxyphenolate]

Reaction of zinc iodide, sodium azide and 2-[(3-dimethylaminopropylimino)methyl]-6-ethoxyphenol (HL) results in the formation of a trinuclear complex [Zn₃L₂(μ_1,1-N₃)₂I₂]. The complex is characterized by elemental analysis, IR spectroscopy, and X-ray crystallography. The complex possesses crystallographic two-fold rotation axis symmetry and crystallizes in the monoclinic system, C2/c space group, a = 23.241(2) Å, b = 10.849(1) Å, c = 17.384(2) Å, β = 120.868(1)°, V = 3762.4(6) ų, Z = 4. The molecule consists of two [ZnL(N₃)I] units connected together by a central Zn atom. The terminal Zn atom is fivecoordinated in a trigonal-bipyramidal geometry, and the central Zn atom is six-coordinated in an octahedral geometry. The Zn...Zn separation between the terminal and the central Zn atoms is 3.257(2) Å.     

[η<Superscript>5</Superscript>-C<Subscript>9</Subscript>H<Subscript>5</Subscript>(1,3-SiMe<Subscript>3</Subscript>)<Subscript>2</Subscript>]HfCl<Subscript>3</Subscript>: A monomeric 12-electron half-sandwich complex

The half-sandwich hafnium complex [gh⁵-C₉H₅(1,3-SiMe₃)₂]HfCl₃ (II) has been synthesized for the first time. The molecular structures of II and its synthetic precursor C₉H₅(1,1,3-SiMe₃)₃ (I) have been determined by X-ray crystallography. Compound II in the crystalline state, is a rare example of a monomeric 12-electron half-sandwich complex.     

Experimental Determination of the Isotherm at 15°C of the System Mg<Superscript>2+</Superscript>/Cl<Superscript>−</Superscript>, SO<Subscript>4</Subscript><Superscript>2</Superscript>–H<Subscript>2</Subscript>O

Summary.  The diagram of the ternary system Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O was established at 15°C by means of analytical and conductimetric measurements. Three compounds were found in this diagram, which are MgSO₄·6H₂O, MgSO₄·7H₂O, and MgCl₂·6H₂O. The solubility field of MgSO₄·7H₂O is important whereas those of MgSO₄·6H₂O and MgCl₂·6H₂O are small. The compositions (mass-%) of the two invariant points determined by the two methods are: MgSO₄:MgCl₂=2.73:33.80 and MgSO₄: MgCl₂=3.38:28.91. Both the measured and the calculated isotherm at 15°C have been used for modelling of the diagram Mg²⁺/Cl⁻, SO₄ ²⁻–H₂O between 0 and 35°C. The polythermal invariant point was approximately located between 15 and 10°C.  Corresponding author. E-mail: ariguib@planet.tn Received October 16, 2002; accepted (revised) December 3, 2002 Published online April 24, 2003 RID="a" ID="a" Dedicated to Prof. Dr. Heinz Gamsj?ger on the occasion of his 70^th birthday     

Crystal structure of Cs[(UO<Subscript>2</Subscript>)<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(OH)] · H<Subscript>2</Subscript>O

Single crystals of Cs[(UO₂)₂(C₂O₄)₂(OH)] · H₂O were synthesized and structurally studied using X-ray diffraction. The compound crystallizes in monoclinic space group P2₁/m, Z = 2, with the unit cell parameters a = 5.5032(4) Å, b = 13.5577(8) Å, c = 9.5859(8) Å, β = 97.012(3)°, V = 709.86(9) ų, R = 0.0444. The main building units of crystals are [(UO₂)₂(C₂O₄)₂(OH)]^? layers of the A₂K ₂ ⁰² M² (A = UO ₂ ²⁺ , K⁰² = C₂O ₄ ^2? , and M² = OH^?) crystal-chemical family. Uranium-containing layers are linked into a three-dimensional framework via electrostatic interactions with outer-sphere cations and hydrogen bonds with water molecules.     

Platinum–Ruthenium Cluster Complexes from the Reaction of Ru<Subscript>3</Subscript>(CO)<Subscript>12</Subscript> with Pt(PBu<Superscript>t</Superscript><Subscript>3</Subscript>)<Subscript>2</Subscript>

Three new platinum–ruthenium complexes: Pt₃Ru₃(PBu^t ₃)₃(CO)₁₂, 8, Pt₅Ru₃(PBu^t ₃)₃(CO)₁₂, 9 and PtRu₃(PBu^t ₃)₂(CO)₈(μ₃-PBu^t)(μ-H)₂, 10 were obtained from the reaction of Ru₃(CO)₁₂ with Pt(PBu^t ₃)₂. Compound 8 was obtained from this reaction when conducted at 25 °C. Compounds 9 and 10 were obtained when the reaction was conducted at 68 °C. The structure of 8 consists of a central triangular cluster of three ruthenium atoms with one Pt(PBu^t ₃) group bridging each of the three Ru–Ru bonds. The structure of 9 consists of a capped pentagonal bipyramidal cluster of eight metal atoms that is formed formally by the addition of two platinum atoms to 8. The structure of 10 contains a triangular cluster of three ruthenium atoms with a Pt(PBu^t ₃) group bridging one of the Ru–Ru bonds. A t-butyl phosphido ligand formed by degradation of a molecule of PBu^t ₃ bridges the three ruthenium atoms. This report is dedicated to the memory of Professor F. A. Cotton for his many pioneering contributions to inorganic and metal cluster chemistry.     

Sb(III) fluoride complexes with DL-valine. Crystal structure of molecular complex SbF<Subscript>3</Subscript>{(CH<Subscript>3</Subscript>)<Subscript>2</Subscript>CHCH(<Superscript>+</Superscript>NH<Subscript>3</Subscript>)COO<Superscript>−</Superscript>}

Preparative method in combination with X-ray diffraction and IR spectroscopy is used to study reaction of Sb(III) fluoride with -aminoisovaleric acid (DL-valine) in an aqueous solution in the range of the molar ratios of components (0.25–2) : 1 in the presence of hydrofluoric acid. The molecular complex of Sb(III) fluoride with valine (1 : 1) of the composition SbF₃{(CH₃)₂CHCH(⁺NH₃)COO^–}(I) and valinium tetrafluoro-antimonate(III) monohydrate {(CH₃)₂CHCH(₊NH₃)COOH}SbF₄· H₂O (II) are synthesized for the first time. Crystal structure was determined for the molecular complex I consisting of SbF₃ groups and valine molecules united into polymer chains through bidentate bridging carboxylate groups of amino acid molecules.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 2, 2005, pp. 125–131.Original Russian Text Copyright © 2005 by Zemnukhova, Davidovich, Udovenko, Kovaleva.