Membrane purification of Cl2 gas: I. Permeabilities as a function of temperature for Cl2, O2, N2, H2 in two types of PDMS membranes

Permeability (P) of Cl₂, O₂, N₂ and H₂ was measured in polydimethylsiloxane (PDMS) composite membranes with two different degrees of cross-linking. The permeability was measured in the low pressure range (1–3 bar absolute) over a fairly large temperature range 35–120°C. The functionalities of the membranes were compared on the basis of permeation rate and ability to separate the gases Cl₂–O₂. These results are part of an extensive survey where perfluorinated and carbon membranes are also included (not reported here). The purpose of the project is to develop an industrial membrane with high permselectivity for either O₂ or Cl₂ (depending on the type of membrane) at temperatures preferably above 70°C. Process conditions are set in an industrial project. The PDMS membranes are good candidates for this separation, having a high permeation rate for Cl₂ and a selectivity of Cl₂/O₂ in the range of 8–25 depending on temperature. Durability of the PDMS membranes in this aggressive environment is found to be very dependent on process conditions and on how the material is polymerized and cured. For documentation of durability, various silicones were tested; these results are to be reported separately.     

Thermochemistry of the higher chlorine oxides ClOx (x=3, 4) and Cl2Ox (x=3–7)†

Heats of formation for ClO₃, ClO₄, Cl₂O₃, Cl₂O₄, Cl₂O₅, Cl₂O₆ and Cl₂O₇ molecules are determined at the B3LYP, B3PW91, mPW1PW91 and B1LYP levels of the density functional theory employing a series of extended basis sets, and using Gaussian-3 model chemistries. Modified Gaussian-3 calculations, which employ accurate B3LYP/6-311+G(3d2f) molecular geometries and vibrational frequencies, were also performed. Heats of formation were calculated from both total atomization energies and isodesmic reaction schemes. The latter method in conjunction with Gaussian-3 models leads to the most reliable results. The best values at 298 K for ClO₃, ClO₄, Cl₂O₃ and Cl₂O₄ as derived from an average of G3//B3LYP and G3//B3LYP/6-311+G(3d2f) calculations are 43.1, 54.8, 31.7 and 37.4 kcal mol⁻¹. From calculations carried out at the G3(MP2)//B3LYP and G3(MP2)//B3LYP/6-311+G(3d2f) levels, heats of formation for Cl₂O₅, Cl₂O₆ and Cl₂O₇ are predicted to be 53.2, 52.2 and 61.5 kcal mol⁻¹. All best values are reproduced within 1 kcal mol⁻¹ by using mPW1PW91/6-311+G(3d2f) isodesmic energies. Enthalpy changes for relevant Cl–O bond fission reactions are reported. Comparisons with previous thermodynamics data are made.     

The thermal decomposition reactions of [Co(en)n(phen)m]Cl3 complexes

The thermal behaviour of [Co(en)_n(phen)_m]Cl₃ complexes has been studied using thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) in air, nitrogen and oxygen atmospheres. The effect of the stoichiometry of the complexes and that of the gas atmosphere in the furnace chamber on the thermal decomposition reaction is evidenced and discussed. The following thermal stability order has been found [Co(en)₃]Cl₃ [Co(en)₂(phen)]Cl₃ > [Co(en)(phen)₂]Cl₃ [Co(phen)₃]Cl₃     

Titanium imido complexes containing 1,3,5-triazacyclohexane ligands

The syntheses of the 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane-supported imido complexes [M(NR)(R′₃tach)Cl₂] (M = Ti or Zr (NMR only); R = Bu^t or 2,6-C₆H₃Prⁱ₂; R′ = Me or Bu^t) are reported, along with that of the thermally robust dibenzyl derivative [Ti(NBu^t)(Me₃tach)(CH₂Ph)₂]. The tert-butylimido ligand in [Ti(NBu^t)(Me₃tach)Cl₂] undergoes exchange with ArNH₂ (Ar = 4-C₆H₄Me or 2,6-C₆H₄Me or 2,6-C₆H₃Prⁱ₂) to form the corresponding arylimides [Ti(NAr)(Me₃tach)Cl₂]. The Me₃tach ring in [Ti(NR)(Me₃tach)Cl₂] undergoes slow exchange with Bu^t₃tach or Me₃tacn (1,4,7-trimethyl-1,4,7-triazacyclononane) to give the ring-exchanged products [Ti(NR)(Bu^t₃tach)Cl₂] and [Ti(NR)(Me₃tacn)Cl₂], respectively. The complexes [Ti(NR)(Me₃tach)X₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂; X = Cl or CH₂Ph) exhibit room-temperature dynamic NMR behaviour via an unusual trigonal twist of the facially coordinated Me₃tach ligand, and the activation parameters for these processes have been measured and are discussed. The X-ray structures of [Ti(NR)(Bu^t₃tach)Cl₂] (R = Bu^t or 2,6-C₆H₃Prⁱ₂) and [Ti(NBu^t)(Me₃tach)(X)₂] [X= Cl or CH₂Ph) are reported. Me₃tach and Bu^t₃tach = 1,3,5-trimethyl- and tri-tert-butyl-1,3,5-triazacyclohexane, respectively.     

有机膦溴化钯(Ⅱ)配合物的合成、结构及其催化偶联反应活性

以PdBr2为起始原料,分别选择二叔丁基苯基膦((t-Bu)2PPh)、二叔丁基-(4-二甲基氨基苯基)膦(Amphos)、4,5-双二苯基膦-9,9-二甲基氧杂蒽(Xantphos)为有机膦配体,通过溶剂的配位加成和有机膦的配位取代,合成出3种溴化钯配合物,以寻找性能更佳的偶联催化剂.借助元素分析仪、核磁共振仪及单晶...     

Basis set effects on the stability of the Cl2O3 isomers using B3P86 and B3LYP methods of density functional theory

Four Cl₂O₃ isomers have been calculated using density functional theory with B3P86 and B3LYP functionals and various basis sets. The energy hypersurfaces of Cl₂O₃ are very flat and the relative energies of the isomers which have hypervalent characters such as ClOCl(O)O and ClClO₃ are strongly dependent on the basis sets. The stability for Cl₂O₃ isomers are in the order of (1)ClOOOCl(C_s), (2)ClOOOCl(C₂), (3)ClClO₃ and (4)ClOCl(O)O with ClOCl(O)O being most stable. We suggest that at least the cc-pV6Z(-ghi) basis set for Cl and the cc-pVTZ basis set for O are required to obtain reliable relative stabilities of Cl₂O₃ isomers with hypervalent characters.     

Polarized absorption spectra and polarized Raman spectra of single crystals of trans(Cl2)-[CoCl2(NH3)n(H2O)4−n]Cl complexes (n = 2, 3, 4)

The title cobalt(III) complexes have been investigated by polarized absorption and Raman spectroscopies of the single crystals. The symmetry properties of the d-electron orbitals and of the vibrational modes attributable to the Raman bands of trans(Cl₂)-[CoCl₂(NH₃)_n(H₂O)_4−n]Cl complexes (n = 2, 3, or 4) were examined to elucidated the peculiar observation that ligand substitution causes no splitting of the 15 200-cm⁻¹ absorption band and the 250-cm⁻¹ Raman band. Effects of replacing the NH₃ ligand with H₂O on the electronic structure, atom–atom force constants and vibrational modes of these complex ions are briefly described.     

Synthesis and characterization of oxo---imido and alkyl---imido complexes of molybdenum(VI)

Treatment of the complex Mo(Nmes)(O)Cl₂(dme) (mes=2,4,6-trimethylphenyl; dme=1,2-dimethoxyethane) with KTp^Me2, NaCp and bipy gives the corresponding derivatives (Tp^Me2)Mo(Nmes)(O)Cl (1), CpMo(Nmes)(O)Cl (2) and Mo(Nmes)(O)Cl₂(bipy) (3). Other oxo---imido compounds of composition Mo(Nmes)(O)(S₂CNR₂)₂ (R₂=C₄H₄ 4, C₅H₁₀ 5, ⁱPr₂ 6) can be obtained by reacting Mo(Nmes)(O)Cl₂(dme) with the appropriate dithiocarbamate salt. The NMR properties of 4–6 are consistent with the presence of two rapidly equilibrating dithiocarbamate ligands. The reaction of Mo(Nmes)(O)Cl₂(dme) with different Grignard reagents, Mg(R)X, produces the trialkyl imido complexes Mo(Nmes)R₃Cl (R=Me 7, CH₂C(Me)₂Ph 8, CH₂SiMe₃ 9).     

Cl2/TiCl4体系引发IBVE活性阳离子聚合的研究(Ⅰ)——引发活性中心及其络合竞争

采用UV光谱法证明了IBVE/Cl₂/TiCl₁/甲苯聚合体系中同时存在着两种引发活性中心及络合竞争,研究了Cl₂/TiCl₁和H₂O/TiCl₁络合平衡,求出了20℃时2TiCl₁←Cl₂和TiCl₁←H₂O络合平衡不稳定常数.     

Template-directed Synthesis of Three Metal Oxalates via 4-Connected Building Units

Three novel compounds, [Co（en）3]2[Zr2（C2O4）7]·2H20（HNU-2, en=ethylenediamine）, [Co（NH3）6]· [Ce（CzO4）3（H2O）]·H2O（HNU-3） and [Co（dien）2][Gd（C2On）3]·0.75H2O（HNU-4, dien=dethylenetriamine） were hydro- thermal synthesized based on the templates of [Co（en）3]C13, [C0（NH3）6]C13 and [Co（dien）2]C13, respectively. The Zr4＋ Ce3＋ and Gd3＋ cations are all coordinated by four oxalates to form [M（C2O4）n（H2O）n]m （M=Zr, Ce or Gd; n=0 or 1; m=4 or 5）, which are similar to [In（C2O4）4]5- in NKB-1, and can be regarded as 4-connected building units. The [M（C2O4）a（H2O）n]m units are connected via sharing the bis-bidentate bridging oxalate ligands to form binuclears in HNU-2 and 1D ＂zigzag＂ chains in HNU-3 and HNU-4. cular building units to design 3D open frameworks with It is suggested that these compounds could be used as mole- zeolite topologies.     

Characterization and crystal structures of copper(II), cobalt(II), and nickel(II) complexes with two kinds of piperidine carboxylic acids

Copper(II) complex with -piperidine-3-carboxylic acid ( -Hpipe-3):[Cu( -pipe-3)₂(H₂O)] and cobalt(II) and nickel(II) complexes with piperidine-4-carboxylic acid (Hpipe-4):[M(Hpipe-4)₂(H₂O)₄]Cl₂ (M: Co, Ni) have been prepared and characterized by means of IR and powder diffuse reflection spectra, thermal analysis, and magnetic susceptibility. The crystal structures of these complexes have been determined by X-ray diffraction. The crystal of [Cu( -pipe-3)₂(H₂O)] is orthorhombic with the space group Pbcn. The copper atom is in a square pyramidal geometry, ligated by two carboxylato oxygen atoms, two nitrogen atoms, and a water molecule. One molecule of this complex consists of either -piperidine-3-carboxylic acid or -piperidine-3-carboxylic acid. The crystals of [M(Hpipe-4)₂(H₂O)₄]Cl₂ are monoclinic with space group P2₁/n. In these complexes the metal atom is in an octahedral geometry ligated by two carboxylato oxygen atoms and four water molecules.     

Preparation of certain chloromethyl- and dichloromethyl-substituted chlorodisilanes and their behavior toward aluminum halides

Four new (chloromethyl)disilanes, (ClCH₂)Cl₂SiSiCl₂Me (I), (Cl₂CH)Cl₂SiSiCl₂Me(II), (ClCH₂)MeClSiSiClMe₂(III) and (ClCH₂)Me₂SiSiCl₃(IV), have been prepared and studied as to their attitude toward intramolecular rearrangement with aluminum chloride. The reactivity decreases in the order: (III) > (IV) > (II) (I). Similar reactivity to rearrangement of Me₃SiSiMe₂(CH₂Br)(V), ClMe₂SiSiMe₂(CH₂Br) (VI) and Me₃SiSiMeCl(CH₂Br) (VII) in the presence of aluminum bromide has been found to decrease in the order: (V) > (VI) > (VII). The results are discussed in terms of a mechanism favoring initial rate-determining step of ionization of the carbon-halogen bond in which the migrating group plays a minor role, if any, followed by migration of a silyl group from silicon to carbon. Disilanes (I) and (II) enter into the Friedel-Crafts reaction with benzene to give, after methylation, PhCH₂SiMe₂SiMe₃ and Ph₂CHSiMe₂SiMe₃, respectively.     

胺基邻菲咯啉-钌(Ⅱ)反应性荧光指示剂的合成与化学固定的研究

为减少荧光指示剂被水萃取流失,提高荧光膜的使用寿命,将5-氨基-邻菲咯啉与二(4,7-二苯基-邻菲咯啉)二氯化钌(Ⅱ)络合,合成带氨基的荧光指示剂[Ru(dpp)₂(phen-NH₂)]Cl₂,并经氨基键合到有机玻璃表面。以核磁、质谱、红外验证合成荧光指示剂的结构,研究键合条件对染色有机玻璃荧光发射的影响,监测荧光强度随水浸泡时间的变化。合成荧光指示剂的荧光发射峰值波长为570 nm,键合到有机玻璃后发射光谱红移20 nm,荧光强度受溶解氧影响,响应时间约为10 s,氧猝灭比达4。染色有机玻璃的荧光稳定性好,在50 ℃水中浸泡7个月,荧光强度下降小于1%。     

The phenomenon of conglomerate crystallization: Part 52. Stereochemical control of the crystallization pathway by small alterations of ligands

The X-ray structure analysis of mer-trans-[Co(aepn)Cl₂(OH₂)](ClO₄)·H₂O (1) (aepn=N-(2-aminoethyl)-1,3-propanediamine) reveals that the compound crystallizes in an enantiomorphic space group P2₁2₁2₁ implying a spontaneous resolution of its racemic solution, known as conglomerate crystallization. Substitutions of the two chloride ligands with bromides result in the isostructural compound mer-trans-[Co(aepn)Br₂(OH₂)](ClO₄)·H₂O (2), which also crystallizes as a conglomerate in the space group P2₁2₁2₁. Meanwhile, a substitution of the coordinated OH₂ of 1 with NH₃ gives mer-trans-[Co(aepn)Cl₂(NH₃)](ClO₄) (3), which crystallizes as a simple racemate in P2₁/n space group. When N-(3-aminopropyl)-1,3-propanediamine (dpt) is used instead of aepn in the preparation of 1, it gives racemic crystals of mer-trans-[Co(dpt)Cl₂(OH₂)](ClO₄) (4) whose molecular packing pattern is identical to that of 3. In the conglomerate structures, the protons of coordinated water ligand are strongly hydrogen-bonded to the oxygen of a water of crystallization to form a spiral packing structures. In the packing structures of 3 and 4, two molecules of opposite chirality are brought together around a crystallographic center of inversion by hydrogen bonds of the protons of the corresponding tridentate amine ligand with oxygens of perchlorate anion.     

三元体系LaCl3-Am(Am=Gly,Glu,Ser)-H2O(25℃)的研究

测定了3个三元体系LaCl₃-Am-H₂O(Am=Gly,Glu,Ser)在25℃时的溶度和饱和溶液的折光指数。报道了三元体系中生成的三元配合物La(Gly)Cl₃·2H₂O(A₁)、La(Gly)₃Cl₃·3H₂O(A₂)、La₂(Glu)₃Cl₆·8H₂O(C)、La(Ser)Cl₃·3H₂O(E)。用摩尔电导、红外光谱、X射线衍射、热分析及偏光显微镜鉴测定了各配合物的一些物理化学性质。     

Synthesis, characterisation and reactivity of trans-[Ru(L)(PPh3)Br2]; L=2-pyridyl-N-(2′-methylthiophenyl)methyleneimine: Crystal structure of trans-[Ru(L)(PPh3)Br2]

Reaction of Ru(PPh₃)₂Br₂ with the NNS chelating tridentate ligand 2-pyridyl-N-(2′-methylthiophenyl)methyleneimine (L) led to the isolation of the ruthenium(II) complex [Ru(L)(PPh₃)Br₂]. Reactivity of this complex with different bidentate chelating ligands revealed that the products are quite different from those obtained by reacting Ru(L)(PPh₃)Cl₂ (the corresponding cis dichloro complex) with the same ligands under comparable conditions. The mixed chelates were isolated and characterised by elemental analysis, magnetic moment measurement and by different spectroscopic methods along with their precursor. Electrochemistry of the complexes was examined by cyclic voltammetry using a platinum working electrode and a Ag/AgCl electrode as reference. The crystal structure of [Ru(L)(PPh₃)Br₂] disclosed that, unlike Ru(L)(PPh₃)Cl₂, the two bromo ligands are in trans position and this explained the difference in its reactivity pattern from the corresponding chloro complex.     

Inverse phase transfer catalysis. Kinetics of the pyridine 1-oxide-catalyzed reactions of dichlorobenzoyl chlorides and benzoate ions

The substitution reactions of 2,3-, 2,4-, 3,4-, or 3,5-dichlorobenzoyl chloride (Cl₂C₆H₃COCl) and 2,3-, 2,4-, 3,4-, or 3,5-dichlorobenzoate ion (Cl₂C₆H₅COO⁻) or benzoate ion (C₆H₅COO⁻) in a two-phase H₂O/CH₂Cl₂ medium using pyridine 1-oxide (PNO) as an inverse phase transfer catalyst were investigated. The reaction of Cl₂C₆H₃COCl and PNO in CH₂Cl₂ to produce the ionic intermediate, 1-(dichlorobenzoyloxy)-pyridinium chloride (Cl₂C₆H₃COONP⁺Cl⁻) is the rate-determining step. In the PNO-catalyzed two-phase reaction of Cl₂C₆H₃COCl and C₆H₅COONa, the order of reactivities of Cl₂C₆H₃COCl toward reaction with PNO is (2,3-, 2,4-)>3,5->3,4-2,6-Cl₂C₆H₃COCl, whereas it is 3,5->(2,3-, 3,4-)>2,4-Cl₂C₆H₃COCl in the PNO-catalyzed two-phase reaction of Cl₂C₆H₃COCl and the corresponding Cl₂C₆H₃COONa. The order of reactivities of Cl₂C₆H₃COO⁻ ions towards the reaction with 1-(benzoyloxy)-pyridinium (C₆H₅COONP⁺) ion is (3,4-, 3,5-)>(2,3-, 2,4-Cl₂C₆H₃COO⁻).     

Stereoselective synthesis of esters with vinylsilicon functionality via ruthenium carbene catalyzed cross-metathesis

A new catalytic route for the synthesis of unsaturated organosilicon compounds with vinylic functionality based on cross-metathesis of vinyltrialkoxy- and vinyltris(trimethylsiloxy)-silanes with allyl esters of carboxylic acids catalyzed by ruthenium carbenes (Grubbs catalysts): [Cl₂(PCy₃)₂Ru(=CHPh)] (I), [Cl₂(PCy)₃(1,3-dimesityl-4,5-dihydroimidazol-2-ylidene)Ru(=CHPh)] (II) is reported. The efficient reaction can be extended to alkyl esters of unsaturated acids, e.g., of methyl 3-butenoate.     

Free radical inactivation of pepsin

Alkylperoxy radicals containing one, two or three chlorine atoms, CO^-₂, O₂ ^- were reacted with pepsin in aqueous solutions. It was found that only Cl₃COO and CO^-₂ inactive pepsin, attacking preferentially the disulfide bridge. Transient spectra obtained upon completion of the Cl₃COO + pepsin reaction at pH 5 indicate that 20% of initially produced Cl₃COO radicals oxidizes tryptophan residues, and 40% disulfide bridges. The inactivation induced by the Cl₃COO radical increases at lower pH, and the maximal inactivation, G_in = 5.8, was observed at pH 1.5. The inactivation of pepsin by CO^-₂ radicals depends on the absorbed dose. The maximal inactivation, G_in = 4.5, was determined in the dose range from 38 to 53 Gy.     

Nuclear magnetic resonance of Zn(II) complexes with 2,2′-bipyridine

The complexes Zn(bipy)Cl₂ and Zn(bipy)₂Cl₂ as well as 2,2′-bipyridyl in aqueous solution (D₂O) have been examined by the NMR method. The presence of the monocationic bipy D⁺ form in aqueous bipyridyl solution has been found. The changes of chemical shifts of bipyridyl protons for complexes Zn(bipy)₃Cl₂ and Zn(bipy)Cl₂ have confirmed explicitly the essential influence of diamagnetic currents on the NMR spectrum of Zn(bipy)₃Cl₂. The comparison of the spectra of 2,2′-bipyridyl (in CH₃OH) and of Zn(bipy)Cl₂ may also suggest the presence of the nonbonding metal-proton 6 interaction.