Formation of an oxo-free rhenium(v) complex with 2-aminothiophenol

The reaction of a twofold molar excess of 2-aminothiophenol (H₂L) with trans-[ReOCl₃(PPh₃)₂] in benzene led to the isolation of the oxo-free rhenium(V) complex [ReCl(PPh₃)L₂] (1). IR, ¹H NMR and X-ray crystallographic results indicate that the ligands L coordinate in a dianionic amidothiolate form to the metal and that the complex has the unusual skew-trapezoidal bipyramidal geometry. The ligands L have an average bite angle of 78.8(1)°, with average Re–N and Re–S bond lengths equal to 1.978(5) and 2.297(1)?Å, respectively.     

Kinetics of the reactions of hydroxyl radicals (OH) and of chlorine atoms (Cl) with methylethylether over the temperature range 274–345 K

The rate constants for the gas-phase reactions between methylethylether and hydroxyl radicals (OH) and methylethylether and chlorine atoms (Cl) have been determined over the temperature range 274–345 K using a relative rate technique. In this range the rate constants vary little with temperature and average values of k_MEE+OH = (6.60_−2.62^+3.88) × 10⁻¹² cm³ molecule⁻¹ s⁻¹ and k_MEE+Cl= (34.9 ± 6.7) × 10⁻¹¹ cm³ molecule⁻¹ s⁻¹ were obtained. The atmospheric lifetimes of methylethylether have been estimated with respect to removal by OH radicals and Cl atoms to be ca. 2 days and ca. 30–40 days, respectively. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 231–236, 1997.     

Synthese und Eigenschaften von cis-Diacidophthalocyaninato(2–)thallaten(III); Kristallstruktur von Tetra(n-butyl)ammonium-cisdinitrito(O,O′)- und -cis-dichlorophthalocyaninato(2–)thallat(III)

Syntheses and Properties of cis -Diacidophthalocyaninato(2–)thallates(III); Crystal Structure of Tetra(n-butyl)ammonium cis -dinitrito(O,O ′)- and cis -dichlorophthalocyaninato(2–)thallate(III) Blue green cis-diacidophthalocyaninato(2–)thallate(III), ^cis[Tl(X)₂pc^2–]^– (X = Cl, ONO′, NCO) is prepared from iodophthalocyaninato(2–)thallium(III) and the corresponding tetra(n-butyl)ammonium salt, (ⁿBu₄N)X in dichloromethane, and isolated as (ⁿBu₄N)^cis[Tl(X)₂pc^2–]. (ⁿBu₄N)^cis[Tl(ONO′)₂pc^2–] ( 1 ) and (ⁿBu₄N)^cis[Tl(X)₂pc^2–] · 0,5 (C₂H₅)₂O ( 2 ) crystallize in the monoclinic space group P2₁/n with cell parameters for 1: a = 14.496(2) Å, b = 17.293(5) Å, c = 18.293(2) Å, β = 98.76(1)° resp. for 2 : a = 13.146(1) Å, b = 14.204(5) Å, c = 24.900(3) Å, β = 93.88(1)°; Z = 4. In 1 , the octa-coordinated Tl atom is surrounded by four isoindole-N atoms (N_iso) and four O atoms of the bidental nitrito(O,O′) ligands in a distorted antiprism. The Tl–N_iso distances vary between 2.257(3) and 2.312(3) Å, the Tl–O distances between 2.408(3) and 2.562(3) Å. In 2 , the hexa-coordinated Tl atom ligates four N_iso atoms and two Cl atoms in a typical cis-arrangement. The average Tl–N_iso distance is 2.276 Å, the average Tl–Cl distance is 2.550 Å. In 1 and 2 , the Tl atom is directed out of the centre of the (N_iso)₄ plane (Ct_N) towards the acido ligands (d(Tl–Ct_N) = 1.144(1) Å in 1 , 1.116(2) Å in 2 ), and the phthalocyaninato ligand is concavely distorted. The vertical displacements of the periphereal C atoms amounts up to 0.82 Å. The optical and vibrational spectra as well as the electrochemical properties are discussed.     

Radical polymerization of benzyl N-(2,6-dimethylphenyl)itaconamate

The polymerization of benzyl N-(2,6-dimethylphenyl)itaconamate (BDMPI) with benzoyl peroxide (BPO) in N,N-dimethylformamide (DMF) was studied kinetically by ESR. The polymerization rate (R_p) at 70°C was given by R_p = k[BPO]^0.78[BDMPI]^1.1. The overall activation energy of polymerization was determined to be 83.7 kJ/mol. The number-average molecular weight of poly(BDMPI) was in the range of 1500–2000 by gel permeation chromatography. From the ESR study, the polymerization system was found to involve ESR-observable propagating radicals of BDMPI under practical polymerization conditions. Using the polymer radical concentration by ESR, the rate constants of propagation (k_p) and termination (k_t) were determined in the temperature range of 50–70°C. The k_p value seemed dependent on the chain-length of propagating radical. The analysis of polymers by the MALDI-TOF mass spectrometry suggested that most of the resulting polymers contain the dimethylamino terminal group. The copolymerization of BDMPI (M₁) and styrene (M₂) at 50°C in DMF gave the following copolymerization parameters; r₁ = 0.49, r₂ = 0.26, Q₁ = 1.2, and e₁ = +0.63. The thermal behavior of poly(BDMPI) was examined by dynamic thermogravimetry and differential scanning calorimetry. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35 : 1891–1900, 1997     

Tris(1,10‐phenanthroline‐κ2N,N′)iron(II) bis(2,4,5‐tricarboxybenzoate) monohydrate and tris(2,2′‐bipyridine‐κ2N,N′)iron(II) 2,5‐dicarboxybenzene‐1,4‐dicarboxylate–benzene‐1,2,4,5‐tetracarboxylic acid–water (1/1/2)

The title compounds, tris(1,10‐phenanthroline‐κ²N,N′)iron(II) bis(2,4,5‐tricarboxybenzoate) monohydrate, [Fe(C₁₂H₈N₂)₃](C₁₀H₅O₈)₂·H₂O, (I), and tris(2,2′‐bipyridine‐κ²N,N′)iron(II) 2,5‐dicarboxybenzene‐1,4‐dicarboxylate–benzene‐1,2,4,5‐tetracarboxylic acid–water (1/1/2), [Fe(C₁₀H₈N₂)₃](C₁₀H₄O₈)·C₁₀H₆O₈·2H₂O, (II), were obtained during an attempt to synthesize a mixed‐ligand complex of Fe^II with an N‐containing ligand and benzene‐1,2,4,5‐tetracarboxylic acid via a solvothermal reaction. In both mononuclear complexes, each Fe^II metal ion is six‐coordinated in a distorted octahedral manner by six N atoms from three chelating 1,10‐phenanthroline or 2,2′‐bipyridine ligands. In compound (I), the Fe^II atom lies on a twofold axis in the space group C2/c, whereas (II) crystallizes in the space group P2₁/n. In both compounds, the uncoordinated carboxylate anions and water molecules are linked by typical O—H...O hydrogen bonds, generating extensive three‐dimensional hydrogen‐bond networks which surround the cations.     

Darstellung und Eigenschaften von Tetra(n-butyl)ammonium-cis-trifluorophthalocyaninato(2–)zirconat(IV) und -hafnat(IV); Kristallstruktur von (nBu4N)cis[Hf(F)3pc2–]

Preparation and Properties of Tetra(n-butyl)ammonium cis -Trifluorophthalocyaninato(2–)zirconate(IV) and -hafnate(IV); Crystal Structure of (ⁿBu₄N) ^cis [Hf(F)₃pc^2–] cis-Dichlorophthalocyaninato(2–)metal(IV) of zirconium and hafnium reacts with excess tetra(n-butyl)-ammoniumfluoride trihydrate to yield tetra(n-butyl)-ammonium cis-trifluorophthalocyaninato(2–)metalate(IV), (ⁿBu₄N)^cis[M(F)₃pc^2–] (M = Zr, Hf). (ⁿBu₄N)^cis[Hf(F)₃pc^2–] crystallizes in the monoclinic space group P2₁/n (# 14) with cell parameters a = 13.517(1) Å, b = 13.856(1) Å, c = 23.384(2) Å, α = 92.67(1)°, Z = 4. The Hf atom is in a ”︁square base-trigonal cap”︁”︁ polyhedron, coordinating three fluorine atoms and four isoindole nitrogen atoms (N_iso). The Hf atom is sandwiched between the (N_iso)₄ and F₃ planes (d(Hf–Ct_N) = 1.218(3) Å; d(Hf–Ct_F) = 1.229(3) Å; Ct_N/F: centre of the (N_iso)₄, respectively F₃ plane). The average Hf–N_iso and Hf–F distances are 2.298 and 1.964 Å, respectively, the average F–Hf–F angle is 84.9°. The pc^2– ligand is concavely distorted. The optical spectra show the typical metal independent π-π* transitions of the pc^2– ligand at c. 14700 and 29000 cm^–1. In the FIR/MIR spectra vibrations of the MF₃ skeleton are detected at 545, 489, 274 cm^–1 (M = Zr) and 536, 484, 263 cm^–1 (M = Hf), respectively.     

A New Class of Heterobinuclear Complexes: Crystal Structure and Magnetism of Copper(II)‐Nickel(II) Complexes Incorporating Two Different Macrocyclic Ligands

Three novel oxamido‐bridged heterobinuclear copper(II)‐nickel(II) complexes incorporating two different tetraazamacrocyclic compounds were synthesized and characterized by IR, ESR, and electronic spectra. They are of the formulas [(CuL¹)Ni(rac‐cth)](ClO)₄₂⋅H₂O ( 1 ), [Cu(L²)Ni(rac‐cth)](ClO₄)₂⋅0.5 EtOH ( 2 ), and [(CuL³)Ni(rac‐cth)](ClO₄)₂⋅H₂O ( 3 ). L¹, L², and L³ are the dianions of diethyl 5,6,7,8,16,17‐hexahydro‐6,7‐dioxo‐15H‐dibenzo[e,n][1,4,8,12]tetraazacyclopentadecine‐13,19‐dicarboxylate, diethyl 5,6,7,8,15,16‐hexahydro‐6,7‐dioxodibenzo[1,4,8,11]tetraazacyclotetracine‐13,18‐dicarboxylate, and diethyl 5,6,7,8,15,16‐hexahydro‐15‐methyl‐6,7‐dioxodibenzo[1,4,8,11]tetraazacyclotetradecine‐13,18‐dicarboxylate, respectively, and rac‐cth is rac‐5,7,7,12,14,14‐hexamethyl‐1,4,8,11‐tetraazacyclotetradecane. The crystal structures of 1 and 2 were determined by single‐crystal X‐ray analysis. The Ni^II ion is pseudooctahedrally coordinated. The coordination geometry around the Cu^II ion in 2 is slightly distorted square planar, while that in 1 shows significant distortion towards a tetrahedral structure. The temperature dependence of the magnetic susceptibility for 1 and 2 was analyzed by means of the Hamiltonian Hˆ =−2J Sˆ ₁⋅ Sˆ ₂, leading to J=−63.9 and −67.4 cm⁻¹ for 1 and 2 , respectively.     

Polymerization of arylallenes catalyzed by organo-rhodium(I) and -cobalt (I) complexes to give structurally regulated high-mass polymers

Organorhodium complexes, such as RhH(PPh₃)₄, RhH(CO)(PPh₃)₃, Rh(η³-C₃H₄Ph)(CO)(PPh₃)₂, and RhH(dppe)₂ [dppe = 1,2-bis(diphenylphosphinoethane)], catalyze polymerization of phenylallene and of 4-methylphenylallene at 60 °C. High-molecular-weight polymers (M_n>4×10⁵) are isolated from the reaction products by removing the low-molecular-weight (M_n<3×10³) acetone-soluble fraction. The NMR (¹H and ¹³C{¹H}) spectra of poly(phenylallene) (1) and poly(4-methylphenylallene) (2) show the structure formed through selective 2,3-polymerization of the monomers, while similarly obtained poly(2-naphthylallene) (3) is characterized only by ¹H NMR spectroscopy due to its low solubility in common organic solvents. 4-Fluorophenylallene and 4-(trifluoromethyl)-phenylallene do not polymerize under similar conditions in the presence of RhH(PPh₃)₄ catalyst but are turned into low-molecular-weight oligomers. CoH(N₂)(PPh₃)₃-catalyzed polymerization of phenylallene and 4-methylphenylallene at room temperature gives the corresponding polymers with molecular weights in the range M_n=(9–15)×10⁴, in high yields. © 1997 John Wiley & Sons, Ltd.     

C–H-Aktivierung: Synthese und Eigenschaften von Acetonato(C)acidophthalocyaninato(2–)metallaten(III) von Rhodium und Iridium; Kristallstruktur von Tetra(n-butyl)ammoniumacetonato(C)-azidophthalocyaninato(2–)iridat(III)

C–H-Activation: Syntheses and Properties of Acetonato( C )-acidophthalocyaninato(2–)metallates(III) of Rhodium and Iridium; Crystal Structure of Tetra(n-butyl)ammonium Acetonato( C )azidophthalocyaninato(2–)iridate(III) Phthalocyaninato(2–)metallate(I) of rhodium and iridium reacts with carbonyl substrates like acetone or acetylacetone and halides or pseudohalides forming acetonato(C)- or acetylacetonato(C)acidophthalocyaninato(2–)metallates(III), that are isolated as tetra(n-butyl)ammonium complex salts (ⁿBu₄N)[M(R)(X)pc^2–] (M = Rh, Ir; R = aC, acaC; X = Cl, I, N₃, SCN/NCS). (ⁿBu₄N)[Ir(aC)(N₃)pc^2–] · 0,25(C₂H₅)₂O · 0,5 CH₂Cl₂ crystallizes in the triclinic space group P1 with cell parameters a = 16.267(8) Å, b = 17.938(3) Å, c = 18.335(4) Å, α = 74.77(2)°, β = 73.73(3)°, γ = 84.25(3)°, V = 4954(3) ų, Z = 4. There are two crystallographically independent anions, differing by the orientation of the azido ligand either towards an isoindole group or a N_aza bridge of the phthalocyaninate, while the σ-C bonded acetonate is always oriented towards an isoindole group (gauche and ecliptical configuration). The Ir–C distances are 2.12(1) and 2.14(1) Å. Due to the trans influence of the acetonate-C atom the Ir-azide-N distances of 2.22(1)/2.24(1) Å are longer than expected. The electrochemical properties and the optical, vibrational, and ¹H-NMR spectra are discussed.     

trans-Bis(triphenylphosphin)phthalocyaninato(2–)rhenium(II): Synthese,Eigenschaften und Kristallstruktur

trans -Bis(triphenylphosphine)phthalocyaninato(2–)rhenium(II): Synthesis, Properties, and Crystal Structure Dirheniumheptoxide reacts with phthalodinitrile in boiling 1-chloronaphthalene and subsequent reprecipitation of the green raw product from conc. sulfuric acid to yield an oxo-phthalocyaninate of rhenium, which is reduced by molten triphenylphosphine forming dark green trans-bis(triphenylphosphine)phthalocyaninato(2–)rhenium(II), ^trans[Re(PPh₃)₂pc^2–]. The latter crystallizes triclinic in the space group P 1 with the cell parameters as follows: a = 11.512(2) Å, b = 12.795(2) Å, c = 12.858(2) Å, α = 64.42(2)°, β = 79.45(2)°, γ = 72.74(1)°; V = 1628.1(5); Z = 1. Re is in the centre of the (N_p)₄ plane (N_p: N1, N3) and coordinates two triphenylphosphine ligands axially in trans position. The average Re–N_p and Re–P distances are 2.007(1) and 2.516(3) Å, respectively. Despite the many extra bands the typical B, Q and N regions of the pc^2– ligand are observed at ca. 16500, 28900/32900 and 35300 cm^–1. A weak band group at ca. 8900 cm^–1 is attributed to a trip-multiplet transition, another one at ca. 14500 cm^–1 to a P → Re charge transfer. The vibrational spectra are dominated by internal vibrations of the pc^2– ligand. The very weak intensity of the IR bands at 905 and 1327 cm^–1 are diagnostic of the presence of Re^II.     

Bis(triphenylphosphin)iminium-bis(methoxo)phthalocyaninato(2–)ferrat(III) – Synthese und Kristallstruktur

Bis(triphenylphosphine)iminium Bis(methoxo)phthalocyaninato(2–)ferrate(III) – Synthesis and Crystal Structure Chlorophthalocyaninato(2–)ferrate(III) reacts with bis(triphenylphosphine)iminium hydroxide in methanol/acetone solution to yield blue crystals of bis(triphenylphosphine)iminium bis(methoxo)phthalocyaninato(2–)ferrate(III). The complex salt crystallizes as an acetone/methanol solvate (^bPNP)[Fe(OCH₃)₂pc^2–] · (CH₃)₂CO · 1.5 CH₃OH in the triclinic space group P 1 (no. 2) with the cell parameters a = 13.160(5) Å, b = 15.480(5) Å, c = 17.140(5) Å, α = 97.54(5)°, β = 91.79(5)°, γ = 95.44(5)°. The Fe atom is located in the centre of the pc^2– ligand coordinating four isoindole N atoms (N_iso) of the pc^2– ligand and two O atoms of the methoxo ligands in a mutual trans arrangement. The average Fe–O and Fe–N_iso distances are 1.887 and 1.943 Å, respectively. The cation adopts the bent conformation (< P–N–P = 140.4(2)°) with P–N distances of 1.579(3) and 1.575(3) Å.     

A temperature‐dependent kinetics study of the reaction of O(3PJ) with (CH3)2SO

A laser flash photolysis–resonance fluorescence technique has been employed to investigate the kinetics of the reaction of ground state oxygen atoms, O(³P_J), with (CH₃)₂SO (dimethylsulfoxide) as a function of temperature (266–383 K) and pressure (20–100 Torr N₂). The rate coefficient (k_R1) for the O(³P_J) + (CH₃)₂SO reaction is found to be independent of pressure and to increase with decreasing temperature. The following Arrhenius expression adequately describes the observed temperature dependence: k_R1(T) = (1.68 ± 0.76) × 10_?12 exp[(445 ± 141)/T] cm³ molecule^?1 s^?1, where the uncertainties in Arrhenius parameters are 2σ and represent precision only. The absolute accuracy of each measured rate coefficient is estimated to be ±30%, and is limited predominantly by the uncertainties in measured (CH₃)₂SO concentrations. The observed temperature and pressure dependencies suggest that, as in the case of O(³P_J) reactions with CH₃SH and (CH₃)₂S, reaction occurs by addition of O(³P_J) to the sulfur atom followed by rapid fragmentation of the energized adduct to products. The O(³P_J) + (CH₃)₂SO reaction is fast enough so that it could be a useful laboratory source of the CH₃SO₂ radical if this species is produced in significant yield. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 156–161, 2002; DOI 10.1002/kin.10040     

Assembled synthesis of luminescent mono/double‐layered 2D and 3D Zn (II)‐based coordination polymers tuned by flexible bis (pyridyl)propane‐1,2‐diamines and diverse organic dicarboxylates

Six mono/double‐layered 2D and three 3D coordination polymers were synthesized by a self‐assembly reaction of Zn (II) salts, organic dicarboxylic acids and L1/L2 ligands. These polymeric formulas are named as [Zn(L1)(C₄H₂O₄)_0.5 (H₂O)]_n·0.5n(C₄H₂O₄)·2nH₂O ( 1 ), [Zn₂(L2)(C₄H₂O₄)₂]_n·2nH₂O ( 2 ), [Zn(L1)(m‐BDC)]_n ( 3 ), [Zn₂(L2)(m‐BDC)₂]_n·2nH₂O ( 4 ), [Zn₃(L1)₂(p‐BDC)₃(H₂O)₄]_n·2nH₂O ( 5 ), [Zn₂(OH)(L2) (p‐BDC)_1.5]_n ( 6 ), [Zn₂(L1)(p‐BDC)₂]_n·5nH₂O ( 7 ), [Zn₂(L2)(p‐BDC)₂]_n·3nH₂O ( 8 ) and [Zn₂(L1)(C₄H₄O₄)_1.5(H₂O)]_n·n(ClO₄)·nH₂O ( 9 ) [L1 = N,N′‐bis (pyridin‐4‐ylmethyl)propane‐1,2‐diamine, L2 = N,N′‐bis (pyridin‐3‐ylmethyl)propane‐1,2‐ diamine, m‐BDC^2? = m‐benzene dicarboxylate, p‐BDC^2? = p‐benzene dicarboxylate]. Meanwhile, these polymers have been characterized by elemental analysis, infrared, thermogravimetry (TG), photoluminescence, powder and single‐crystal X‐ray diffraction. Polymers 1–6 present mono‐ and double (4,4)‐layer motifs accomplished by L1/L2 ligands with diverse conformations and organic dicarboxylates, and the layer thickness locates in the range of 5.8–15.0 Å. In three 3D polymers, the L1 and L2 molecules adopt the same cis‐conformations and join adjacent Zn (II) cations together with p‐BDC^2? or succinate, giving rise to different binodal (4,4)‐c nets with (4.5².8³)(4.5³.7²) ( 7 ), pts ( 8 ) topology and twofold interpenetrated binodal (5,5)‐c nets with (3².4⁴.5².6²)(3.4³.5².6⁴) ( 9 ). Therefore, the diverse conformations of the two bis (pyridyl)‐propane‐1,2‐diamines and the feature of different organic dicarboxylate can effectively influence the architectures of these polymers. Powder X‐ray diffraction patterns demonstrate that these bulk solid polymers are pure phase. TG analyses indicate that these polymers have certain thermal stability. Luminescent investigation reveals that the emission maximum of these polymers varies from 402 to 449 nm in the solid state at room temperature. Moreover, 1 , 3 and 5–8 show average luminescence lifetimes from 8.81 to 16.30 ns.     

Synthesis and characterization of N -(alky(aryl)carbamothioyl)cyclohexanecarboxamide derivatives and their Ni(II) and Cu(II) complexes

N-(R-carbamothioyl)cyclohexanecarboxamides (R: diethyl, di-n-propyl, di-n-butyl, diphenyl and morpholine-4) and their Ni(II) and Cu(II) complexes have been synthesized and characterized by elemental analyses, FT-IR and NMR methods. N-(diethylcarbamothioyl)cyclohexanecarboxamide, HL¹, C₁₂H₂₂N₂OS, crystallizes in the orthorhombic space group P2₁2₁2₁, with Z = 4, and unit cell parameters, a = 6.6925(13) Å, b = 9.0457(18) Å, c = 22.728(5) Å. The conformation of the HL¹ molecule with respect to the thiocarbonyl and carbonyl moieties is twisted, as reflected by the torsion angles O1–C6–N2–C5, C6–N2–C5–N1 and S1–C5–N2–C6 of 1.68°, ?67.47° and 115.50°, respectively. The structure of HL¹ also shows a delocalization of the π electrons of the thiocarbonyl group over the C–N bonds. The ring puckering analysis shows that the cyclohexane ring has a chair conformation. The bis(N-(morpholine-4-carbonothioyl)cyclohexane carboxamido)nickel(II) complex, Ni(L⁵)₂, C₂₄H₃₈N₄NiO₄S₂, crystallizes in the monoclinic space group P2₁/c, with Z = 4, and unit cell parameters, a = 16.919(3) Å, b = 8.3659(17) Å, c = 19.654(4) Å, β = 107.43(3)°. Ni(L⁵)₂ is a cis-complex with a slightly distorted square-planar coordination of the central nickel by two oxygen and two sulfur atoms.     

Tantalum(v) oxoalkoxides. Synthesis and structure

Anodic oxidation of tantalum in isopropyl alcohol or prolonged reflux of an alcohol solution of Ta(OPrⁱ)₅ afford crystalline oxoisopropoxide Ta₂O(OPrⁱ)₈ · PrⁱOH (1). In its molecule, two octahedra about Ta atoms are linkedvia the shared edge [(OPrⁱ)O]. Compound1 is the first example of oxoalkoxide containing such a small number of metal atoms. Unlike the known polynuclear molecules M _n O _m (OR) _p , oxoalkoxide1 is stable in solutions; on transition to the gas phase, this compound is desolvated to form a very stable molecule Ta₂O(OPrⁱ)₈ (apparently, consisting of two octahedra with a shared edge). According to the data of mass spectrometry, analogous molecules exist in the gas phase over Ta(OAlk)₅ (Alk = Me, Et, Prⁱ, or Bu¹¹). When compound1 is heated invacuo (10^–2–10^–3 Torr), Ta(OPrⁱ)₅ is sublimated. Crystals of Ta₇O₉(OPrⁱ)₁₇ (2) were formed upon prolonged storage of solutions of1 in PrⁱOH. Heptanuclear molecule2 consists of two [Ta₄] tetrahedra with a shared vertex. These tetrahedra are additionally linked togethervia one ₃-oxo and two ₂-OPrⁱ groups. Complex2 is a representative of heptameric oxoalkoxides of a new structural type.Deceased in I995.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 125–131, January, 1996.     

Kinetics of the reactions of Cl(2PJ) and Br(2P3/2) with O3

A laser flash photolysis-resonance fluorescence technique has been employed to study the kinetics of the important stratospheric reactions Cl(²P_J) + O₃ → ClO + O₂ and Br(²P_3/2) + O₃ → BrO + O₂ as a function of temperature. The temperature dependence observed for the Cl(²P_J) + O₃ reaction is nonArrhenius, but can be adequately described by the following two Arrhenius expressions (units are cm³ molecule^?1 s^?1, errors are 2σ and represent precision only): ??₁(T) = (1.19 ± 0.21) × 10^?11 exp [(?33 ± 37)/T] for T = 189–269K and ??₁(T) = (2.49 ± 0.38) × 10^?11 exp[(?233 ± 46)/T] for T = 269–385 K. At temperatures below 230 K, the rate coefficients determined in this study are faster than any reported previously. Incorporation of our values for ??₁(T) into stratospheric models would increase calculated ClO levels and decrease calculated HCl levels; hence the calculated efficiency of ClO_x catalyzed ozone destruction would increase. The temperature dependence observed for the (²P_3/2) + O₃ reaction is adequately described by the following Arrhenius expression (units are cm³ molecule^?1 s^?1, errors are 2σ and represent precision only): ??₂(T) = (1.50 ± 0.16) × 10^?1 exp[(?775 ± 30)/T] for T = 195–392 K. While not in quantitative agreement with Arrhenius parameters reported in most previous studies, our results almost exactly reproduce the average of all earlier studies and, therefore, will not affect the choice of ??₂(T) for use in modeling stratospheric BrO_x chemistry.     

Investigation of the water exchange mechanism of the Plutonyl(VI) and Uranyl(VI) ions with quantum chemical methods

The water exchange reactions of [PuO₂(OH₂)₅]²⁺ and [UO₂(OH₂)₅]²⁺ were investigated with density functional theory (DFT) and wave function theory (WFT). Geometries and vibrational frequencies were calculated with DFT and CPCM hydration. The electronic energies were evaluated with general multiconfiguration quasi-degenerate second-order perturbation theory (GMC-QDPT2). Spin-orbit (SO) effects, computed with SO configuration interaction (SO–CI), are negligible. Both Actinyl(VI) ions react via an associative exchange mechanism, most likely I_a. The Gibbs activation energies (ΔG^?) at 25 °C are 33–34 and 30–37 kJ mol^?1 for [PuO₂(OH₂)₅]²⁺ and [UO₂(OH₂)₅]²⁺, respectively. ΔG^? for dissociative mechanisms (D, I_d) is higher by more than 15 kJ mol^?1.     

Four silver-containing coordination polymers based on bis(imidazole) ligands

Four coordination polymers, [Ag(L¹)](m-Hbdc) (1), [Ag(L¹)]₂(p-bdc)?·?8H₂O (2), [Ag(Hbtc)(L¹)][Ag(L¹)]?·?2H₂O (3) and [Ag₂(L²)₂](OH-bdc)₂?·?4H₂O (4), where L¹?=?1,1′-(1,4-butanediyl)bis(imidazole), L²?=?1,2-bis(imidazol-1-ylmethyl)benzene, m-H₂bdc?=?1,3-benzenedicarboxylic acid, p-H₂bdc?=?1,4-benzenedicarboxylic acid, H₃btc?=?1,3,5-benzenetricarboxylic acid, and OH–H₂bdc?=?5-hydroxisophthalic acid, were synthesized under hydrothermal conditions. Compound 1 contains a–Ag-L¹–Ag-L¹–chain and a hydrogen-bonding interaction induced–(m-Hbdc)-(m-Hbdc)–chain. Compound 2 consists of two independent–Ag-L¹–Ag-L¹–chains. P-bdc anions are not coordinated. Hydrogen bonds form a 3D supramolecular structure. A novel (H₂O)₁₆ cluster is formed by lattice water molecules in 2. Compound 3 contains a–Ag-L¹–Ag-L¹–and a–Ag(Hbtc)-L¹–Ag(Hbtc)-L¹–chain. The packing diagram shows a 2D criss-cross supramolecular structure, with?π?···?π?and C–H ···?π?interactions stabilizing the framework. Compound 4 contains a [Ag₂(L²)₂]²⁺ dimer with hydrogen-bonding,?π?··· π, and Ag ··· O interactions forming a 3D supramolecular framework. The luminescent properties for these compounds in the solid state are discussed.