High-energy kinetic study of chemically activated 1,1-dichlorocyclopropane

1,1-Dichlorocyclopropane has been produced by addition of CH₂(¹A₁) to 1,1-dichloroethylene. CH₂(¹A₁) was generated by the photolysis of ketene at 277–334 nm. The 1,1-dichlorocyclopropane was formed in a chemically activated state, had an energy content between 386 and 400 kJ/mol, and reacted in two parallel channels to 2,3-dichloropropene and 1,1-dichloropropene. 1,1-Dichloropropene was also formed directly by insertion of CH₂(¹A₁) into the CH bond of 1,1-dichloroethylene. As secondary reactions elimination of HCl from chemically activated 2,3-dichloropropene occurred with 3-chloropropyne and chloroallene as products. In some of the experiments perfluoropropane was added as an inert gas. The apparent rate constants for the isomerization and elimination reactions are reported. The results of RRKM calculations including distribution functions for the activated 1,1-dichlorocyclopropane and a step-ladder model for the deactivation verify the proposed reaction scheme.     

A cross-linker containing aldehyde functionalized ionic liquid for chitosan

The synthesis of conductive and eco-friendly new chitosan composite biopolymer with a novel aldehyde functionalized ionic liquids (AFILs) was investigated in this work. The AFILs, 1,1′-(pentane-1,5-diyl) bis(4-formylpyridin-1-ium) dibromide (C₅PyBr), 1,1′-(octane-1,8-diyl) bis(4-formylpyridin-1-ium) dibromide (C₈PyBr) and 1,1′-(decane-1,10-diyl) bis(4-formylpyridin-1-ium) dibromide (C₁₀PyBr) have been synthesized and they were characterized by FT-IR, UV–vis and ¹H-NMR and ¹³ C-NMR, TG, and DSC analyses. The synthesized AFILs, C₅PyBr C₈PyBr and C₁₀PyBr were used as cross-linker for chitosan biopolymers and the cross-linked chitosan composites, chitosan/1,1′-(pentane-1,5-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₅PyBr), chitosan/1,1′-(octane-1,8-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₈PyBr) and chitosan/1,1′-(decane-1,10-diyl)bis(4-formylpyridin-1-ium)dibromide (Ch/C₁₀PyBr) were prepared. Herein, the synthesized AFILs have not only cross-linked chitosan, but also provide them the desired novel, functional groups. The prepared chitosan composites were characterized by FT-IR for the analysis of structural, TG and DSC for the thermal behavior, and an electrometer for the electrical conductivity. The electrical conductivity of the prepared Ch/C₅PyBr composite was measured as 1.69?×?10^?5 ± 2.37?×?10^?5 S cm^?1 by the four-point probe at room temperature and this value is higher about 4500-fold than the electrical conductivity of the chitosan.     

1,1‐Organoboration of silylethynyltin compounds studied by multinuclear magnetic resonance spectroscopy: isomerization at the CC bonds and electron‐deficient Si?H?B bridges

1,1‐Organoboration, using triethyl‐, triallyl‐ and triphenyl‐borane (BEt₃, BAll₃, BPh₃), of dimethysilylethynyl(trimethyl)stannane, Me₃Sn? C?C? Si(H)Me₂ ( 1 ), affords alkenes bearing three different organometallic groups at the C?C bond. For BEt₃ and BPh₃, the first products are the alkenes 4 with boryl and stannyl groups in cis‐positions. These rearrange by consecutive 1,1‐deorganoboration and 1,1‐organoboration into the isomers 5 as the final products, where boryl and silyl groups are in cis‐positions linked by an electron‐deficient Si? H? B bridge. 1,1‐Ethylboration of bis(dimethylsilylethynyl)dimethylstannane, Me₂Sn[C?C? Si(H)Me₂]₂ ( 2 ), leads to the stannacyclopentadiene 6 along with non‐cyclic di(alkenyl)tin compounds 7 and 8 . 1,1‐Ethylboration of ethynyl(trimethylstannylethynyl)methylsilane, Me(H)Si(C?C? SnMe₃)C?C? H ( 3 ), leads selectively to a new silacyclopentadiene 13 as the final product. The reactions were monitored and the products were characterized by multinuclear magnetic resonance spectroscopy (¹H, ¹¹B, ¹³C, ²⁹Si and ¹¹⁹Sn NMR). Copyright © 2005 John Wiley & Sons, Ltd.     

Ether-Functionalized Pyrrolidinium-Based Room Temperature Ionic Liquids: Physicochemical Properties,Molecular Dynamics,and the Lithium Ion Coordination Environment

The physicochemical properties of room temperature ionic liquids (RTILs) consisting of bis(trifluoromethanesulfonyl)amide (TFSA⁻) combined with 1-hexyl-1-methylpyrrolidinium (Pyr_1,6⁺), 1-(butoxymethyl)-1-methylpyrrolidinium (Pyr_1,1O4⁺), 1-(4-methoxybutyl)-1-methyl pyrrolidinium (Pyr_1,4O1⁺), and 1-((2-methoxyethoxy)methyl)-1-methylpyrrolidinium (Pyr_1,1O2O1⁺) were investigated using both experimental and computational approaches. Pyr_1,1O2O1TFSA, which contains two ether oxygen atoms, showed the lowest viscosity, and the relationship between its physicochemical properties and the position and number of the ether oxygen atoms was discussed by a careful comparison with Pyr_1,1O4TFSA and Pyr_1,4O1TFSA. Ab initio calculations revealed the conformational flexibility of the side chain containing the ether oxygen atoms. In addition, molecular dynamics (MD) calculations suggested that the ion distributions have a significant impact on the transport properties. Furthermore, the coordination environments of the Li ions in the RTILs were evaluated using Raman spectroscopy, which was supported by MD calculations using 1000 ion pairs. The presented results will be valuable for the design of functionalized RTILs for various applications.     

Nickel(I)‐Komplexe mit 1,1′‐Bis(phosphino)ferrocenen als Liganden

Nickel(I) Complexes with 1,1′‐Bis(phosphino)ferrocenes as Ligands The thermically stable monomeric Nickel(I) complexes [(d^tbpf)Ni(acac)] ( 1 ) and [(dⁱppf)NiCl] ( 2 ) were synthesized and characterized by elemental analyses, EPR spectroscopy, and by X‐ray crystal structure analyses of single crystals (d^tbpf: 1,1′‐bis(di‐tertbutylphosphino)ferrocene; dⁱppf: 1,1′‐bis(diisopropylphosphino)ferrocene). 1 is formed by reduction of Ni(acac)₂ with triethylaluminium in the presence of d^tbpf, together with the nickel(0) complex [(d^tbpf)Ni(C₂H₄)]. 1 contains a Ni^I atom surrounded of two O‐ and two P donor atoms in a distorted tetrahedral coordination. 2 was obtained by reduction of [(dⁱppf)NiCl₂] with NaBH₄. In 2 the nickel(I) atom adopts trigonal planar coordination.     

The stoichiometric hydrogenation of substituted phenyl alkenes by hydridocobalt tetracarbonyl

The relative rates of hydrogenation of a series of styrenes, phenylpropenes, 1,1-diphenylethylenes, and 1,1-diphenylpropenes were measured. Compared to 1,1-diphenylethylene (k₂ = 2.42 X 10^-2 I mol^-1 sec^-1), 1,1-diphenylpropene and styrene have relative rates of 0.0045 and 0.011 respectively. The effect of 4-chloro and 4-methoxy substituents on both styrene and diphenylethylene is slightly rate enhancing. An unusual kinetic dependence occurs with mixtures of alkenes.     

Different Complexation Behavior of P‐Functionalized Ferrocene Derivatives Towards SnCl2, SnCl4 and SnPh2Cl2: Auto‐ionization and Redox‐Type Reactions

The novel phosphonyl‐substituted ferrocene derivatives [Fe(η⁵‐Cp)(η⁵‐C₅H₃{P(O)(O‐iPr)₂}₂‐1,2)] ( Fc^1,2 ) and [Fe{η⁵‐C₅H₄P(O)(O‐iPr)₂}₂] ( Fc^1,1′ ) react with SnCl₂, SnCl₄, and SnPh₂Cl₂, giving the corresponding complexes [(Fc^1,2)₂SnCl][SnCl₃] ( 1 ), [{(Fc^1,1′)SnCl₂}_n] ( 2 ), [(Fc^1,1′)SnCl₄] ( 3 ), [{(Fc^1,1′)SnPh₂Cl₂}_n] ( 4 ), and [(Fc^1,2)SnCl₄] ( 5 ), respectively. The compounds are characterized by elemental analyses, ¹H, ¹³C, ³¹P, ¹¹⁹Sn NMR and IR spectroscopy, ³¹P and ¹¹⁹Sn CP‐MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single‐crystal as well as powder X‐ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc^1,1′ and Fc^1,2 towards tin(II) chloride.     

Palladium(II) thiohydrazone complexes: synthesis,spectral characterization and antifungal study

Palladium(II) complexes of type [Pd(L)Cl₂] [where, L?=?benzaldehyde-1,1-diphenyl-2-thiohydrazone (L¹), salicylaldehyde-1,1-diphenyl-2-thiohydrazone (L²), acetaphenone-1,1-diphenyl-2-thiohydrazone (L³) and cyclohexanone-1,1-diphenyl-2-thiohydrazone (L⁴)] have been synthesized. The thiohydrazones can exist as thione-thiol tautomers and coordinate as a bidentate N–S ligand. The ligands are found to be monobasic bidentate. The complexes have been characterized by elemental analysis, IR, mass, electronic, ¹H NMR spectroscopic studies. In vitro antifungal studies against fungi Aspergillus fumigatus, Aspergillus flavus and Aspergillus niger for some complexes have also been carried out.     

13C and 1H chemical shift assignments and conformation confirmation of trimedlure-Y via 2-D NMR

The conformation of 1,1-dimethylethyl 5-chloro-cis-2-methylcyclohexane-1-carboxylate (trimedlure-Y) was confirmed as 1,2,5 equatorial, axial, equatorial via ¹³C, ¹H, APT, CSCM and COSY NMR analyses. The carbon and proton nuclei in trimedlure-Y and the previously unassigned eight cyclohexyl protons (1.50–2.60 ppm) in 1,1-dimethylethyl 5-chloro-trans-2-methylcyclohexane-1-carboxylate (trimedlure-B₁; 1,2,5 equatorial, equatorial, equatorial) were also characterized by these methods. The effects of the 2-CH₃ in the axial or equatorial conformation upon the chemical shifts of the other nuclei in the molecule are discussed.     

Neue Gemischtligandenkomplexe mit Perthiocarboxylaten

New Mixed Ligand Complexes with Perthio Carboxylates Solutions of O-methyl-1,1-dithiooxalate (i-dtoMe) and metal(II)-chlorides (Ni^II, Pd^II) in the molar ratio 2:1 react with equimolar amounts of homonuclear bischelates of other 1,1- and 1,2-dithio-compounds L (L = i-mnt, Etxan, dto) to mixed ligand complexes M(ptoMe)L with spontaneous convertion of the 1,1-dithiooxalate into the corresponding perthio ligand (ptoMe) by sulfur insertion. Tetraphenylphosphonium-(1,1-dicyanoethene-2,2-dithiolato)(O-methyl-1,1 -perthio-oxalato)niccolat(II), Ph₄P[Ni(i-mnt)(ptoMe)], crystallizes in the monoclinic space group P2₁/n with a = 11.019(2) Å, b = 13.648(3) Å, c = 20.882(3) Å, β = 92.565(7)°. The formation of the perthio ligand is confirmed by ¹³C-NMR.     

Mass spectra of methylsubstituted monosila- and monogermacyclobutanes, 1,2- disila- and 1,2-digermacyclopentanes. Some correlations with thermal decomposition

The mass spectra of 1,1-dimethyl-1-silacyclobutane (I—as reported by Cherniak et al.),⁶, 1,1-dimethyl-1-germacyclobutane (II), 1,1,2,2-tetramethyl-1,2-disilacyclopentane (III) and 1,1,2,2-tetramethyl-1,2-digermacyclopentane (IV) are compared and some correlations between electron-impact fragmentation and thermal decomposition are derived. The mass spectra of the germanium compounds with respect to the silicone compounds are enriched by light fragment ions and exhibit lower intensities of odd-electron ions. The composition of some ions and apparently of neutral fragments coincides with that of the unstable intermediates which are suggested in the thermal decomposition mechanism of some related compounds. The loss of C₂H₄ is more characteristic under electron-impact as well as in thermal decomposition of Si-compounds, while C₃H₆ is preferable eliminated by the Ge-compounds.     

Generation of perfluoro- and 1-chloropolyfluorobenzocycloalken-1-yl cations and their relative stability

Treatment of perfluorinated benzocyclobutene, indan, and tetralin with SbF₅-SO₂Cl₂, as well as of their 1,1-dichloro analogs with SbF₅, gave 1-chloropolyfluorobenzocycloalken-1-yl cations whose structure was studied by ¹⁹F and ¹³C NMR and confirmed by their transformations into perfluorinated ketones upon hydrolysis. Dissolution of perfluorinated benzocyclobutene, indan, and tetralin in excess SbF5 generated perfluorobenzocycloalken-1-yl cations in equilibrium with their precursors. The relative stability of perfluoro- and 1-chloropolyfluorobenzocycloalken-1-yl cations decreases as the size of the alicyclic fragment increases.     

Solvent effect in NMR enantiomeric analysis using (S)-1,1′-binaphthyl-2,2′-diol as a chiral solvating agent

The determination of the enantiomeric composition of chiral compounds by¹H,¹³C, and³¹P NMR spectroscopy in the presence of (S)-1,1′-binaphthyl-2,2′-diol demonstrates that the enantioselectivity of the method increases when the polarity of a solvent decreases as follows: CD₃OD-D₂O (4 ∶ 1) < CD₃OD < CDCl₃ < CDCl₃-CCl₄ (1 ∶ 1) < C₆D₆. The effect is caused by increase in stability of solvating agent-substrate complexes formed through the hydrogen bonds. Pantolactone, esters of substituted cyclopropanecarboxylic acids, amino alcohol propranolol, and 2,2′-bis(diphenylphosphinyl)-1,1′-binaphthyl were used as the substrates.     

Synthesis and X-ray structure of 1,1-dimethylhydrazinium azide

1,1-Dimethylhydrazinium azide, [ (CH₃)₂NH–NH₂] [N₃], was prepared in high yield from 1,1-dimethylhydrazine and HN₃ in CH₂Cl₂ solution at −20°C. The new compound has been fully characterized by elemental analysis, multinuclear NMR (¹H, ¹³C, ¹⁴ N, ¹⁵ N) and vibrational spectroscopy (IR, Raman). The structure in the solid state was determined by a low temperature (173 K) single crystal X-ray diffraction analysis.     

Platinum(IV) and palladium(II) thiosemicarbazide and thiodiamine complexes: A spectral and antibacterial study

Platinum(IV) and palladium(II) complexes [Pt(L)₂Cl₂] and [Pd(L)Cl₂], [where, L?=?1,1-diphenyl-2-thiosemicarbazide (L¹) and (1,1-diphenyl-2-thio)-1,3-propanediamine (L²) have been synthesized. The thiosemicarbazides and thiodiamines exist as the thione-thiol tautomer and coordinate as a bidentate N-S ligand. The ligands are monobasic bidentate. The complexes have been characterized by elemental analysis, IR, mass, electronic and 1H NMR spectroscopic studies. In vitro antibacterial studies have also been carried out for some complexes.     

Synthesis and reactivity of cyclopentadienyl iron complexes containing ferrocenyl selenolates

New homo-trimetallic complexes of general formula?1,1??-fc[SeFeCp(CO)₂]₂ (fc?=?Fe(??⁵-C₅H₄)₂) are accessible in high yield by the reaction of 1,1??-fc(SeLi)₂, which is generated from 1,1??-fc(SeSiMe₃)₂ and n-BuLi, with two equivalents of CpFe(CO)₂I. Photolytic CO-substitution reactions of the organoiron diselenolate with bis-phosphines at ?50?°C using 1:2 (metal/ligand) molar ratio afforded 1,1??-fc(SeFeCp(P^P)₂. All these complexes were characterized by physicochemical and spectroscopic methods.     

Tetra-tert-butyl-pentafulvalen als Ligand in zweikernigen Molybdänkomplexen: cis-Anordnung ohne Metall-Metall-bindung

Reaction of 1,1′,3,3′-tetra-tert-butyl-5-′-pentafulvalenedipotassium (1) with hexacarbonylmolybdenum leads to hexacarbonyl-dipotassium(1,1′,3,′-tetra-tert-butyl-5,5′-pemtafulvalene)dimolybdate (2), which on further treatment with stoichiometric amounts of iodomethane yields the hexacarbonyldimethyl(1,1′-3,3′-tetra-tert-butyl-5,5′-pentafulvalene)dimolybdenum, (η⁵ : η⁵-^tBu₄C₁₀H₄)Mo₂(CO)₆-(CH)₃)₂ (3). Compound 3 is obtained as yellow needles and brownish cube-like crystals, and it is characterized by ¹H-NMR, ¹³C-NMR, IR, and MS data. The cubes crystallize in the space group C2/c with four molecules in the unit cell. Each molecule consists of two tricarbonylmethyl(cyclopentadienyl) molybdenum units which are connected by a central CC-bond, twisted against each other by 64.8° and bent by 25.8°. Due to the steric requirements of the tertbutyl substituents in the fulvalene ligand, 3 should be formed only from cis-configurated 2.     

HMBC‐1,1‐ADEQUATE via generalized indirect covariance: a high sensitivity alternative to n,1‐ADEQUATE

1,1‐ADEQUATE and the related long‐range 1,n‐ and n,1‐ADEQUATE variants were developed to provide an unequivocal means of establishing ²J_CH and the equivalent of ⁿJ_CH correlations where n = 3,4. Whereas the 1,1‐ and 1,n‐ADEQUATE experiments have two simultaneous evolution periods that refocus the chemical shift and afford net single quantum evolution for the carbon spins, the n,1‐variant has a single evolution period that leaves the carbon spin to be observed at the double quantum frequency. The n,1‐ADEQUATE experiment begins with an HMBC‐type ⁿJ_CH magnetization transfer, which leads to inherently lower sensitivity than the 1,1‐ and 1,n‐ADEQUATE experiments that begin with a ¹J_CH transfer. These attributes, in tandem, serve to render the n,1‐ADEQUATE experiment less generally applicable and more difficult to interpret than the 1,n‐ADEQUATE experiment, which can in principle afford the same structural information. Unsymmetrical and generalized indirect covariance processing methods can complement and enhance the structural information encoded in combinations of experiments e.g. HSQC‐1,1‐ or ?1,n‐ADEQUATE. Another benefit is that covariance processing methods offer the possibility of mathematically combining a higher sensitivity 2D NMR spectrum with for example 1,1‐ or 1,n‐ADEQUATE to improve access to the information content of lower sensitivity congeners. The covariance spectrum also provides a significant enhancement in the F₁ digital resolution. The combination of HMBC and 1,1‐ADEQUATE spectra is shown here using strychnine as a model compound to derive structural information inherent to an n,1‐ADEQUATE spectrum with higher sensitivity and in a more convenient to interpret single quantum presentation. Copyright © 2012 John Wiley & Sons, Ltd.     

Neue 1,1′-Ferrocendichalkogenato-Komplexe des Rutheniums und Osmiums

New 1,1′-Ferrocene Dichalcogenato Complexes of Ruthenium and Osmium Both trinuclear 1,1′-ferrocene dichalcogenato complexes(¹) such as fc(E[ML_n])₂ ( 1a—c ) (with [ML_n] = Ru(CO)₂Cp*; E = S, Se, Te) and dinuclear [3]ferrocenophane derivatives of the type fcE₂[ML_n] (with [ML_n] = Ru(CO)(η⁶-C₆Me₆) ( 2a, b ), Ru(NO)Cp* ( 3a, b ) (E = S, Se) or Os(NO)Cp* ( 4a—c ) (E = S, Se, Te)) were synthesized and characterized by their IR-, ¹H- and ¹³C NMR spectra as well as their mass spectra. The molecular structure of fcS₂[Os(NO)Cp*] ( 4a ) was determined by an X-Ray structure analysis; the long Fe…?Os distance of 431.1(1)pm excludes any direct bonding interactions.     

Thermodynamic properties of benzoylferrocene and 1,1′-dibenzoylferrocene

The vapor pressures of benzoylferrocene and 1,1′-dibenzoylferrocene were measured by torsion-effusion technique. The following pressure-temperature equations were derived benzoylferrocene log P(kPa) = 10.75±0.22?(5314±82)/T 1,1′-dibenzoylferrocene log P(kPa) = 9.29±0.24?(4898±91 )/T Second-law treatment of the experimental data yielded the sublimation enthalpies for benzoylferrocene and 1,1′-dibenzoylferrocene: ΔH⁰_sub,298 = 116.3±6.0 kJ mole^?1 and ΔH⁰_sub,298 = 109.3±6.0 kJ mole^?1 respectively. Thermal functions of these compounds were also estimated.