Abtrennung und gas-chromatographische Bestimmung von Fluoridspuren

Traces of fluoride can be separated from aqueous solution by extraction with (C₂H₅)₃SiCl in m-xylene or with (C₆H₆)₄SbOH in CH₂Cl₂. Furthermore, several coprecipitation reactions were tested; adsorption on hydroxyl apatite is most suitable.Determination of 0.05 μg F^?/ml can be performed by gas chromatography of (C₂H₅)₃SiF in m-xylene using flame ionisation detectors; but variable blanks of 0.5–1.5 μg F^? normally prevent the determination of less than ca. 3 μg F^?.     

Die Verteilung des Borsäure-Brenzcatechin-Komplexes zwischen wäßrigen Lösungen und organischen Lösungsmitteln

An investigation of several factors involved showed that boric acid can be successfully extracted from weakly acidic aqueous solutions by CH₂Cl₂ as pyrocatechol-tetraphenylphosphonium complex. At concentrations of 4–100μg B/ml (0.2 M pyrocatechol; pH 4.6; CH₂Cl₂ with 1% [C₆H₅]₄PBr) the yield was 95–98%. At smaller concentrations (0.02–0.2 μg B/ml; 0.1 M pyrocatechol) 93–98% were extracted.     

Analyse von Gemischen aus Tri-, Di- und Monophenylzinnverbindungen und anorganischem Zinn(IV)

Triphenyl tin compounds are extracted as (C₆H₅)₃SnOSn(C₆H₅)₃ by CHCl₃ or CH₂Cl₂ from aqueous solution of pH 8.5. Diphenyl tin compounds are separated by solvent extraction with PAN/CHCl₃, diphenylcarbazone/CHCl₃, dithizone/CHCl₃, α-benzoinoxime/CHCl₃, PAR/i-Pentanol etc. Monophenyl tin compounds are extracted by Tropolone/CHCl₃, and inorganic tin(IV) is separated by diethyl dithiocarbaminate/CHCl₃ from acidified solution of pH 4. Several thin-layer chromatographic methods are given. The separated compounds are determined by radiometric or new photometric methods.     

Spektroskopische und röntgenographische Untersuchungen an Dichlormethyl-Quecksilberverbindungen

Spectroscopic and X-Ray Structural Investigations on Dichloromethyl Mercury Compounds Bis(dichloromethyl)mercury, Hg(CHCl₂)₂, and mixed alkyl compounds RHgCHCl₂ (with R = CH₃, C₂H₅) have been synthesized by known methods from CH₂Cl₂, lithium butanide and HgCl₂, CH₃HgCl or C₂H₅HgCl, respectively. The ¹H-, ¹³C-NMR as well as the IR and Raman spectra of the liquid alkyls RHgCHCl₂ and the high melting Hg(CHCl₂)₂ have been measured and assigned. According to the X-ray structure determination Hg(CHCl₂)₂ crystallizes in the monoclinic space group P2₁/c with 4 non-symmetric molecules per unit cell (R = 0.046).     

Thermal‐ and Light‐Induced Spin Crossover in a Guest‐Dependent Dinuclear Iron(II) System

We previously reported the dinuclear material [Fe^II₂(ddpp)₂(NCS)₄] ? 4 CH₂Cl₂ ( 1? 4 CH₂Cl₂; ddpp=2,5‐di(2′,2′′‐dipyridylamino)pyridine) and its partially desolvated analogue ( 1? CH₂Cl₂), which undergo two‐ and one‐step spin‐crossover (SCO) transitions, respectively. Here, we manipulate the type and degree of solvation in this system and find that either a one‐ or two‐step spin transition can be specifically targeted. The chloroform clathrate 1? 4 CHCl₃ undergoes a relatively abrupt one‐step SCO, in which the two equivalent Fe^II sites within the dinuclear molecule crossover simultaneously. Partial desolvation of 1? 4 CHCl₃ to form 1? 3 CHCl₃ and 1? CHCl₃ occurs through single‐crystal‐to‐single‐crystal processes (monoclinic C2/c to P2₁/n to P2₁/n) in which the two equivalent Fe^II sites become inequivalent sites within the dinuclear molecule of each phase. Both 1? 3 CHCl₃ and 1? CHCl₃ undergo one‐step spin transitions, with the former having a significantly higher SCO temperature than 1? 4 CHCl₃ and the latter, and each has a broader SCO transition than 1? 4 CHCl₃, attributable to the overlap of two SCO steps in each case. Further magnetic manipulation can be carried out on these materials through reversibly resolvating the partially desolvated material with chloroform to produce the original one‐step SCO, or with dichloromethane to produce a two‐step SCO reminiscent of that seen for 1? 4 CH₂Cl₂. Furthermore, we investigate the light‐induced excited spin state trapping (LIESST) effect on 1? 4 CH₂Cl₂ and 1? CH₂Cl₂ and observe partial LIESST activity for the former and no activity for the latter.     

Estimation of the desorption energy of dichloromethane and water in MIL-53 by DSC and ab-initio calculations

Desorption energies of dichloromethane(CH_2Cl_2) and water(H_2O) in a metal-organic framework, MIL-53(Al), were investigated by the combination of experimental(differential scanning calorimeter, DSC) and computational(ab-initio calculations) methods. The differences of desorption energy and natural log of the frequency factor of CH_2Cl_2 and H_2O in MIL-53(Al) were analyzed by a thermo active process using DSC measurements. The interaction energy of guest molecules with MIL-53(Al), which corresponds to the desorption in the thermal active process, was explored using ab-initio calculation. As a result of the difference in the interaction energies of H_2O and CH_2Cl_2 in MIL-53(Al), the site near the μ_2-OH groups has two potential wells. Both experimentally and computationally, MIL-53 presents the preferential adsorption of CH_2Cl_2 than H_2O.     

Syntheses and structures of three macrocyclic supramolecular complexes and one ZnII‐containing coordination polymer generated from a semi‐rigid multidentate N‐containing ligand

Semirigid organic ligands can adopt different conformations to construct coordination polymers with more diverse structures when compared to those constructed from rigid ligands. A new asymmetric semirigid organic ligand, 4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine ( L ), has been prepared and used to synthesize three bimetallic macrocyclic complexes and one coordination polymer, namely, bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[dichloridozinc(II)] dichloromethane disolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, ( I ), the analogous chloroform monosolvate, [Zn₂Cl₄(C₁₂H₁₀N₆)₂]·CHCl₃, ( II ), bis(μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine)bis[diiodidozinc(II)] dichloromethane disolvate, [Zn₂I₄(C₁₂H₁₀N₆)₂]·2CH₂Cl₂, ( III ), and catena‐poly[[[diiodidozinc(II)]‐μ‐4‐{2‐[(pyridin‐3‐yl)methyl]‐2H‐tetrazol‐5‐yl}pyridine] chloroform monosolvate], {[ZnI₂(C₁₂H₁₀N₆)]·CHCl₃}_n, ( IV ), by solution reaction with ZnX₂ (X = Cl and I) in a CH₂Cl₂/CH₃OH or CHCl₃/CH₃OH mixed solvent system at room temperature. Complex ( I ) is isomorphic with complex ( III ) and has a bimetallic ring possessing similar coordination environments for both of the Zn^II cations. Although complex ( II ) also contains a bimetallic ring, the two Zn^II cations have different coordination environments. Under the influence of the I^? anion and guest CHCl₃ molecule, complex ( IV ) displays a significantly different structure with respect to complexes ( I )–( III ). C—H…Cl and C—H…N hydrogen bonds, and π–π stacking or C—Cl…π interactions exist in complexes ( I )–( IV ), and these weak interactions play an important role in the three‐dimensional structures of ( I )–( IV ) in the solid state. In addition, the fluorescence properties of L and complexes ( I )–( IV ) were investigated.     

Gas-chromatographic determination of impurities of organic and chlorinated organic compounds and carbon monoxide and dioxide in high-purity hydrogen chloride

A gas-chromatographic procedure was developed for determining impurities (CH₄, C₂H₆, C₃H₈, C₄H₁₀, iso-C₄H₁₀, C₅H₁₂, iso-C₅H₁₂, neo-C₅H₁₂, CH₃Cl, C₂H₅Cl, CH₂Cl₂, CHCl₃, CO, and CO₂) in hydrogen chloride using two columns and a column switching technique in an isothermal mode with a flame ionization detector; the detection limits were 0.01–0.1 ppm. The matrix was separated in a precolumn packed with urea. CO and CO₂ were determined by reaction gas chromatography with their conversion into methane.     

Order-disorder effects of small guests in clathrates studied by nuclear quadrupole resonance and crystallography. Part I. Carbon tetrachloride and related molecules in Ni(SCN)2(3-methylpyridine)4

NQR spectroscopy and X-ray crystallography have been jointly applied to the study of the small guest molecules CH₂Cl₂, CHCl₃, CCl₄, CBr₂Cl₂, C(CH₃)2Cl₂ etc. in the Werner host complex Ni(SCN)₂(3-methylpyridine)₄. Specific host-guest dipole-dipole interactions play an important role in order-disorder effects for guest molecules in the cavities of orthorhombic system,Fddd. Thus a weakly polar molecule such as CBr₂Cl₂ exhibits a disordered alternation, both the bromine and the chlorine atoms occupying the two possible sites in theC ₂ cavity, whereas for the polar molecule C(CH₃)₂Cl₂, an ordered structure is observed. In addition, two new types of crystal structures,C2/c andP , are reported here for dichloromethane and chloroform clathrates.     

Fluorophenylantimony carboxylates(II): synthetic and spectroscopic studies (UV, IR, H, F and C NMR) of pentafluorophenylantimony(V) di- and tetracarboxylates

Pentafluorophenylantimony(V) di- and tetracarboxylates of the molecular formula C₆F₅SbX₂L₂ (when X=L=OCOR (R=CH₃, CH₂Cl, CHCl₂, CCl₃, CF₃, CH₂OC₆H₃Cl₂-2,4, CH₂OC₆H₂Cl₃-2,4,5) and when X=Cl; L=OCOCH_3, OCOCHCl₂) have been synthesized by the metathetical reaction of pentafluorophenylantimony(V) tetrachloride and (dibromide)dichloride with corresponding sodium salt of carboxylic acids in appropriate molar ratio using 15-crown-5 as phase transfer catalyst. The van’t Hoff factor ‘i’ and molar conductance data of the compounds revealed them to be monomeric and non-conducting in nature. Elemental analysis, UV, IR and NMR (¹H, ¹⁹F and ¹³C) were used to characterize the derivatives. Compounds are tentatively assigned as a pentacoordinated square pyramidal structure in which carboxylate ligand behaving as a monodentate ligand.     

Metal complexes of tetradentate and pentadentate N-o-hydroxybenzamido-meso-tetraphenylporphyrin ligand: M(N-NCO(o-OH)C6H4-tpp) (M = Zn2+, Ni2+, Cu2+) and M′(N-NCO(o-O) C6H4-tpp) (M′ = Mn3+) (tpp = 5, 10, 15, 20-tetraphenylporphyrinate)

The crystal structures of N-o-hydroxybenzimido-meso-tetraphenylporphyrinatozinc(II) toluene solvate [Zn(N-NCO(o-OH)C₆H₄-tpp)·C₆H₅CH₃; 4·C₆H₅CH₃], N-o-hydroxybenzimido-meso-tetraphenylporphyrinatonickel(II) chloroform solvate [Ni(N-NCO(o-OH)C₆H₄-tpp)·0.6CHCl₃; 5·0.6 CHCl₃], N-o-hydroxybenzimido-meso-tetraphenylporphyrinatocopper(II) toluene solvate [Cu(N-NCO(o-OH)C₆H₄-tpp)·C₆H₅CH₃; 6·C₆H₅CH₃] and N-o-oxido-benzimido-meso-tetraphenylporphyrinato(-κ⁴,N¹,N²,N³,N⁵,κO²) manganese (III) methylene chloride·methanol solvate [Mn(N-NCO(o-O)C₆H₄-tpp)·CH₂Cl₂·MeOH; 8·CH₂Cl₂·MeOH] were established. The coordination sphere around Zn²⁺ ion in 4·C₆H₅CH₃, (or Ni²⁺ ion in 5·0.6 CHCl₃ or Cu²⁺ ion in 6·C₆H₅CH₃) is a distorted square planar (DSP) whereas for Mn³⁺ in 8·CH₂Cl₂·MeOH, it is a distorted trigonal bipyramid (DTBP) with O(1), N(1) and N(3) lying in the equatorial plane for 8·CH₂Cl₂·MeOH. The g value of 8.27 measured from the parallel polarization of X-band EPR spectra at 293 K is consistent with the high-spin mononuclear manganese(III) (S = 2) in 8. The magnitude of axial (D) zero-field splitting (ZFS) for the mononuclear Mn(III) in 8 was determined approximately as 3.0 cm^?1 by the paramagnetic susceptibility measurements and conventional EPR spectroscopy.     

Bond dissociation energies and radical heats of formation in CH3Cl,CH2Cl2, CH3Br,CH2Br2, CH2FCl,and CHFCl2

An analysis of thermochemical and kinetic data on the bromination of the halomethanes CH_4–nX_n (X = F, Cl, Br; n = 1–3), the two chlorofluoromethanes, CH₂FCl and CHFCl₂, and CH₄, shows that the recently reported heats of formation of the radicals CH₂Cl, CHCl₂, CHBr₂, and CFCl₂, and the C? H bond dissociation energies in the matching halomethanes are not compatible with the activation energies for the corresponding reverse reactions. From the observed trends in CH₄ and the other halomethanes, the following revised ΔH°_f,298 (R) values have been derived: ΔH°_f(CH₂Cl) = 29.1 ± 1.0, ΔH°_f(CHCl₂) = 23.5 ± 1.2, ΔH_f(CH₂Br) = 40.4 ± 1.0, ΔH°_f(CHBr₂) = 45.0 ± 2.2, and ΔH°_f(CFCl₂) = ?21.3 ± 2.4 kcal mol^?1. The previously unavailable radical heat of formation, ΔH°_f(CHFCl) = ?14.5 ± 2.4 kcal mol^?1 has also been deduced. These values are used with the heats of formation of the parent compounds from the literature to evaluate C? H and C? X bond dissociation energies in CH₃Cl, CH₂Cl₂, CH₃Br, CH₂Br₂, CH₂FCl, and CHFCl₂.     

Lyotropic mesomorphic formation of cellulose in trifluoroacetic acid-chlorinated-alkane solvent mixtures at room temperature

Mixtures of trifluoroacetic acid (TFA)-1,2-dichloroethane (1,2-DCE); TFA-dichloromethane (CH₂Cl₂); and TFA-trichloromethane (CHCl₃) are excellent cellulose solvents at room temperature. TFA-1,2-DCE and TFA-CH₂Cl₂ are superior to pure TFA. Lyotropic cellulose mesophases were obtained in (20% w/v) solutions of cellulose in these solvent mixtures. The optical and optical rotatory powers of the solutions suggest that the lyotropic mesophase of cellulose is cholesteric. This implies that cellulose molecules are arranged in helical form in these solvent systems.     

p-Tolylimido rhenium(V) complexes – Synthesis,X-ray studies,spectroscopic characterization and DFT calculations

The p-tolylimido rhenium(V) complexes [Re(p-NC₆H₄CH₃)X₃(EPh₃)₂] (X = Cl, Br; E = As, P) and [Re(p-NC₆H₄CH₃)Cl₂(hmpbta)(PPh₃)]·MeCN have been synthesized and characterized spectroscopically and structurally. The electronic spectra of [Re(p-NC₆H₄CH₃)Cl₃(PPh₃)₂] and [Re(p-NC₆H₄CH₃)Cl₂(hmpbta)(PPh₃)](Hhmpbta-2-(2′-hydroxy-5′-methylphenyl)benzotriazole) were investigated at the TDDFT level employing B3LYP functional in combination with LANL2DZ. Additional information about bonding between the rhenium atom and p-tolylimido ligand in the complexes [Re(p-NC₆H₄CH₃)Cl₃(PPh₃)₂] and [Re(p-NC₆H₄CH₃)Cl₂(hmpbta)(PPh₃)] was obtained by NBO analysis.     

Ethylene polymerization with novel bridged tri- and tetranuclear titanocene/MAO systems

Two benzene centered tri- and tetracyclopentadienyl ligands C₆H₃(CH₂C₅H₅)₃-1,3,5 (1) and C₆H₂(CH₂C₅H₅)₄-1,2,4,5 (2) and their titanium complexes C₆H₃[CH₂C₅H₄Ti(C₅H₅)Cl₂]₃-1,3,5 (3), C₆H₃[CH₂C₅H₄Ti(C₅H₄CH₃)Cl₂]₃-1,3,5 (4), as well as C₆H₂[CH₂C₅H₄Ti(C₅H₅)Cl₂]₄-1,2,4,5 (5) were synthesized and characterized by mass and ¹H NMR spectra. In the presence of methylaluminoxane (MAO), 3, 4 and 5 are efficient catalysts for ethylene polymerization in toluene. The influence of the polymerization conditions such as catalyst concentration, MAO/Ti molar ratio, polymerization time and temperature were investigated in detail. 3, 4 and 5 produce linear polyethylene (PE) with broad molecular weight distributions (MWD) and a little lower molecular weight.     

Unexpected product formed by the reaction of [2,6-(MeOCH2)2C6H3]Li with SbCl3: Structure of Sb-O intramolecularly coordinated organoantimony cation

Reaction of [2,6-(MeOCH₂)₂C₆H₃]Li (1) with SbCl₃ in 1:1 molar ratio yielded except the intended product [2,6-(MeOCH₂)₂C₆H₃]SbCl₂ (2) unexpected complex 3 consisting of antimony anion [Sb₆Cl₂₂]⁴⁻ compensated by four intramolecularly coordinated organoantimony cations [2,6-(MeOCH₂)₂C₆H₃]₂Sb⁺. Compound 3 is labile in CH₂Cl₂(CHCl₃) solution and decomposes to compound 2 and SbCl₃. Both compounds were characterized by the help of ¹H and ¹³C NMR spectroscopy, ESI-mass spectrometry and in the case of 3 by single crystal X-ray diffraction techniques.     

Reaction of NiBr2(DME) with 2-pyridinal-methyl-N-2,6-diisopropylphenylimine. The first crystal structure of an α-diimine nickel(II) complex of the NiL2X2 type

NiBr₂ (DME) (DME = ethylene glycol dimethyl ether) reacts with 2-pyridinal-methyl-N-2,6-diisopropylphenylimine (L) in a 1:1 molar ratio in CH₂Cl₂ to give NiBr₂(L) and [NiBrL₂]Br · 4CH₂Cl₂ in 52% and 14% yield, respectively. The crystal of [NiBrL₂]Br · 4CHCl₃ obtained from CHCl₃ was structurally characterized.     

Manganese(II) complexes of hydrazone based NNO-donor ligands and their catalytic activity in the oxidation of olefins

The reaction between tridentate NNO donor hydrazone ligands, (E)-2-cyano-N′-(phenyl(pyridin-2-yl)methylene)acetohydrazide (HL¹) and (E)-2-cyano-N′-(1-(pyridin-2-yl)ethylidene)acetohydrazide (HL²), with MnCl₂·4H₂O in methanol resulted in [Mn(HL¹)Cl₂(CH₃OH)] (1) and [Mn(HL²)Cl₂(CH₃OH)] (2). Molecular structures of the complexes were determined by single-crystal X-ray diffraction. All of the investigated compounds were further characterized by elemental analysis, FT-IR, TGA, and UV–Vis spectroscopy. These complexes were used as catalysts for olefin oxidation in the presence of tert-butylhydroperoxide (TBHP) as an oxidant. Under similar experimental conditions with equal manganese loading, the presence of [Mn(HL²)Cl₂(CH₃OH)] (2) resulted in higher conversion than [Mn(HL¹)Cl₂(CH₃OH)] (1).     

The reactions of non-gem-hexanedioxytetrachlorocyclotriphosphazene with 2-(2-hydroxyethyl)thiophene,benzyl alcohol and 1,1,3,3-tetramethylguanidine. Spectroscopic studies of the derived products

Abstract

Reactions of non-gem-hexanedioxytetrachlorocyclotriphosphazene (1) with monofunctional nucleophilic reagents, 2-(2-hydroxyethyl)thiophene (2), benzyl alcohol (3) and 1,1,3,3-tetramethylguanidine (4) were investigated. The reactions, using an excess of NaH, in THF solutions, under refluxing conditions and with 1:2?mole ratios allow the synthesis of the following novel cyclotriphosphazene derivatives: 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-[2-(2-ethoxy)hiophene]-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-(C₆H₈OS)₂] (5); 2,4-(hexane-1,6-dioxy)-2,4,6,6-[2-(2-ethoxy) thiophene]-cyclotriphosphazatriene, N₃P₃[O(CH₂)₆O-(C₆H₈OS)₄] (6); 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(methoxybenzene)-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-(C₆H₅CH₂O)₂] (7); 2,4-(hexane-1,6-dioxy)-2,4,6,6-(methoxybenzene)-cyclotriphosphazatriene, N₃P₃[O(CH₂)₆O-(C₆H₅CH₂O)₄] (8); and 2,4-dichloro-2,4-(hexane-1,6-dioxy)-6,6-(1,1,3,3-tetramethyguanidine)-cyclotriphosphazatriene, N₃P₃Cl₂[O(CH₂)₆O-HN-CN₂(CH₃)₄] (9). The structures of the synthesized compounds (5–9) have been characterized by elemental analysis, TLC-MS, ¹H, ¹³C and ³¹P {+¹H} and {?¹H} NMR spectral data.     

35Cl Nqr spectroscopy of the [PO2Cl2]− and POCl3 groups in Me(PO2Cl2)2·2D (Me = Mg,Ca, Mn; D = POCl3,CH3COOC2H5,CH3COCH3)

³⁵Cl NQR spectra of dichlorophosphates Me(PO₂Cl₂)₂ · 2D (Me = Mg, Ca, Mn; D = CH₃COOC₂H₅, CH₃COCH₃, POCl₃) are studied in the temperature range 77 ? T (K) ? 305. It is shown that the three compounds with CH₃COOC₂H₅ as donor are isomorphic at 77 K, the crystal structure of Mn(PO₂Cl₂)₂· 2CH₃COOC₂H₅. The structure of Mg(PO₂Cl₂)_2^?· 2CH₃COCH₃ and of Mg(PO₂Cl₂)₂ · 2POCl₃ probably consists of infinite chains as found for Mn(PO₂Cl₂)₂· 2CH₃COOC₂H₅. Mg(PO₂Cl₂)₂· 2CH₃COOC₂H₅ shows phase transformations and a complicated dynamical behaviour leading to strong deviations from a Bayertype NQR function v = f(T). The donor capacity of POCl₃ in Mg(PO₂Cl₂)₂· 2POCl₃ is comparable with the donor strength in AsCl₃ · POCl₃ · A d_π-p_π overlap of the P-O bond influences the P-Cl bond.