Selective fluorescence sensing of Li+ in an aqueous environment by a ferrocene-anthracene-linked dyad

A new 1-(9-anthryl)-4-ferrocenyl-2-aza-1,3-butadiene showing selective fluorescence enhancement upon binding to lithium cations over other alkaline cations in aqueous environment has been conveniently synthesized and characterized. [structure: see text]     

Crystal and molecular structure of 1-ferrocenyl-r-3,t-5-diphenyl-c-4-(1-ferrocenylvinyl)-1-cyclohexene

X-ray diffraction has been used to establish the crystal and molecular structure of one diastereoisomer of 1-ferrocenyl-3,5-diphenyl-4-(1-ferrocenylvinyl)-1-cyclohexene. This diastereoisomer, formed in the greatest amounts in the protoncatalyzed cyclodimerization of 1-phenyl-3-ferrocenyl-1,3-butadiene, is shown to have the r-3, c-4, t-5 configuration of the exocyclic substituents.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1216–1220, May, 1991.     

Synthesis and utilization of alternative chain transfer agent in cobalt catalyzed 1,3-butadiene polymerization reaction to produce cis-polybutadiene rubber

The cyclodimerization of 1,3-butadiene was performed to synthesize 1,5-cyclooctadiene by using nickel-phosphite based catalyst system. The optimization of cyclodimerization reaction was done to achieve up to 80% selectivity towards 1,5-cyclooctadiene. 1,5-Cyclooctadiene, thus synthesized, was subsequently employed as a chain transfer agent (CTA) for controlling the molecular weight (M.W.) of cis-polybutadiene rubber (BR) in cobalt-complex catalyzed 1,3-butadiene polymerization reaction. The M.W. of BR was reduced from 6.7 to 1.88 × 10⁵ g/mol by escalating the concentration of 1,5-cyclooctadiene from 0% to 0.5% with respect to 1,3-butadiene (monomer) concentration. Similar reducing trend was observed for the Mooney viscosity and gel content of BR with increasing 1,5-cyclooctadiene concentration. The efficacy of 1,5-cyclooctadiene as a CTA for 1,3-butadiene polymerization reaction was further explored by conducting polymerization reaction in various solvents and at higher monomer conversion (∼70%). The effect of 4-vinyl cyclohexene, which was a dominant byproduct during cyclodimerization of 1,3-butadiene, was also investigated. The presence of 4-vinyl cyclohexene has shown adverse effect in the polymerization reaction and was not functioning as a chain transfer agent. Finally, a feasibility of replacement of commercially used gaseous CTA, 1,2-butadiene, by in-house synthesized liquid CTA, 1,5-cyclooctadiene, was also investigated.     

Polymerization and copolymerization of 2-phthalimidomethyll 1,3-butadiene. II. Kinetic study of the polymerization of 1,3-butadiene and of the copolymerization of 1,3-butadiene with 2-phthalimidomethyl 1,3-butadiene initiated by bis-(η3-allyl nickel trifluoroacetate)

The kinetics of the polymerization of 1,3-butadiene initiated by bis(η³-allyl nickel trifluoroacetate) prepared in benzene was studied in methylene chloride at 40°C. The reaction is first order with respect to the monomer, second order with respect to the catalyst in contrast to the case in which solvent is benzene. We have shown that the presence of a polar molecule (fe, N-methyl phthalimide) decreases the overall rate of polymerization. The apparent reactivity ratios for the system 2-phthalimidomethyl 1,3-butadiene (1)-1,3-butadiene (2) are r₁ = 0.65 ± 0.006 and r₂ = 0.48 ± 0.015.     

Aminobutadienes. V. Polymers of 1-phthalimido-1,3-butadiene and 1-succinimido-1,3-butadiene

The radical polymerizations of 1-phthalimido-1,3-butadiene (1-PB) and 1-succinimido-1,3-butadiene (1-SB) were carried out in bulk and in solution. The polymers obtained had reduced viscosities in the ranges of 1.0–4.0 (1-PB) and 0.2–0.6 (1-SB). Both polymers had a similar softening point of 190–200°C. The radical polymerization of 1-phthalimido-1,3-butadiene clearly showed a tendency to give crosslinked polymer. Steric arguments about these polymer structures as a result of the infrared and ozonolysis data led to the conclusion that these polymers contained approximately 20% of the 3,4 form but no 1,2 configuration, and, therefore, that the 1,4 addition was preferred.     

2-alkyl-1,3-butadiene polymerization under the influence of π-allylic complexes of transition metals

Stereoregulation in the polymerization of 2-alkyl-1,3-butadienes with transition metal π-allylic complexes has been studied. The direction of isoprene polymerization is shown to be a function of the nature of the metal and ligands in the allylic compound. The presence of acidic ligands in π-allylic complexes of Zr, Cr, Mo, and Co contributes to 1,4-addition and increases the selectivity of π-allylic nickel complexes, favoring cis-1,4-structure formation. Investigation of the model reaction of 2-alkyl-1,3-butadienes with bis(π-perdeuterocrotyl nickel iodide) revealed that active sites have an π-allylic type structure. The mechanism of formation of π-allylic adducts and the main factors which determine the dependence of direction and rate of polymerization on the nature of a monomer in the diene series: 2-methyl-1,3-butadiene(isoprene), 2-ethyl-1,3-butadiene, 2-isopropyl-1,3-butadiene, and 2-tert-butyl-1,3-butadiene, are discussed.     

Synthesis of 5-vinyl-2-norbornene through Diels-Alder reaction of cyclopentadiene with 1, 3-butadiene in supercritical carbon dioxide

An efficient method for the synthesis of 5-vinyl-2-norbornene from cyclopentadiene and 1,3-butadiene was developed.The Diels-Alder reaction of cyclopentadiene with 1,3-butadiene proceeded smoothly in supercritical carbon dioxide in the absence of any polymerization inhibitor to produce the corresponding 5-vinyl-2-norbornene in satisfactory yield with high selectivity.     

Comparison of catalytic properties of systems based on nickel complexes with 1,4-diaza-1,3-butadiene ligands in reactions of styrene hydrogenation and ethylene polymerization

Turnover frequencies of catalytic systems based on nickel complexes with 1,4-diaza-1,3-butadiene (α-diimine) ligands in the reactions of styrene hydrogenation and ethylene polymerization were determined. Results are presented of a study by the electron paramagnetic resonance method and IR spectroscopy of 1,4-diaza-1,3-butadiene complexes of nickel(II) and anion radicals formed in the interaction of the starting components under the conditions of catalysis. It was shown that the paramagnetic Ni(I) complexes are precursors of complexes catalytically active in the hydrogenation and polymerization reactions.     

The Initiating Effect of Vinyl Aromatic and Diene Monomers on the Polymerization of Isobutylene with VCl4

The polymerization of isobutylene with VCl₄ in n-heptane or in the bulk does not proceed in the dark at temperatures lower than -20°C, yet it may be induced by the addition of styrene, α-methylstyrene, p-divinylbenzene, 1,3-butadiene, isoprene, and 2,3-dimethyl-1,3-butadiene. In these cases the polymerizations proceed with variously long induction periods depending on the type of comonomer used. The shortest induction period was observed after the addition of p-divinylbenzene and 2, 3-dimethyl-1, 3-butadiene. In a nonpolar medium the copolymerization of isobutylene with isoprene or butadiene in the dark gives rise to copolymers insoluble in heptane, benzene, and CCl₄, while co-polymers formed with the effect of light are soluble. Unlike polymerizations carried out in a nonpolar solution, the polymerization of isobutylene with VCl₄ in methyl chloride proceeds spontaneously in the absence of protonic coinitiators. Also, soluble copolymers of isobutylene with isoprene or butadiene arise in the copolymerization in methylchloride solution irrespective of the procedure used when the copolymerization is carried out (in the dark or with the effect of light). Polymerizations and copolymerizations carried out both in nonpolar and in polar solutions are inhibited by the presence of oxygen.     

Synthesis, structure, electrochemistry and ROMP-activity of new ferrocenyl analog of Grubbs’ metathesis catalyst

Treatment of [(PCy₃)₂Cl₂RuCH-Ph] (I) with vinylferrocene 1 and 1-ferrocenyl-1,3-butadiene 2 yielded solid products. These new complexes were characterized by ¹H NMR, ³¹P NMR and ¹³C NMR spectroscopy. X-ray crystal structures of both the complexes have been solved. The crystal structure of II confirmed the assigned structure and revealed existence of two sets of intermolecular C-H-Cl(M) type interactions, viz. (Ru)Cl-H-C(ferrocene) and (Ru)Cl-H-CHCl₂. The air-stable, dark solid II is an efficient catalyst for ring-opening metathesis polymerization (ROMP) of cyclopentene, norbornene and cycloocta-1,5-diene. Electrochemical behavior of the complexes clearly reflects electronic communication between two metal centers.     

3-Ferrocenyl-1-methyl- and 1-ferrocenyl-3-methylcyclopropenes

Dehydrobromination of isomeric 3-bromo-1-ferrocenyl-2-methylcyclopropanes afforded 3-ferrocenyl-1-methyl- and 1-ferrocenyl-3-methylcyclopropenes. These undergo smooth opening of the three-membered ring to give 1- and 2-ferrocenylbuta-1,3-dienes and 1- and 2-methyl-1H-cyclopentaferrocenes; with 1,3-diphenylisobenzofuran they give the classical Diels-Alder adducts.     

Oxidation reaction and thermal stability of 1,3-butadiene under oxygen and initiator

1,3-Butadiene is the simplest conjugated diene, which is widely used in polymer materials, organic synthesis, and other fields. The investigation of its thermal stability and oxidation characteristics is necessary for production, transportation, and use safety. The pressure and temperature behavior of the autoxidation reaction of 1,3-butadiene with oxygen were determined using a custom-designed mini closed pressure vessel test (MCPVT). The effects of free radical initiators CHP and AIBN on the oxidation reaction were investigated. The thermal decomposition characteristics of oxidation products were measured by differential scanning calorimetry (DSC), and its hazards were discussed. The results showed that the oxidation reaction of 1,3-butadiene was easy to occur. Moreover, the activation energies of autoxidation, CHP-initiated oxidation, and AIBN-initiated oxidation reaction were 20.85 kJ·mol^?1, 33.30 kJ·mol^?1, and 56.27 kJ·mol^?1, respectively. In addition, the oxidation products were analyzed by headspace sampler-gas chromatography-mass spectrometry (HS-GC–MS), GC–MS, and iodometry. Some of 1,3-butadiene oxidation products under three conditions are the same, for example, 3-butene-1,2-diol, 4-vinylcyclohexene, 2(5H)-furanone, 2-propen-1-ol, and 2,6-cyclooctadien-1-ol. According to the reaction products, the oxidation reaction pathway of 1,3-butadiene was described. The research results are significant for avoiding fire and explosion accidents in the production, transportation, and application of 1,3-butadiene.     

Reaction of <Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="Italic">N,N</Emphasis>-bis(silatranylmethyl)amine with trichlorosilane

N,N-Bis(silatranylmethyl)methylamine reacts with trichlorosilane to form the amine hydrochloride and perchloropolysilane, the product of polymerization of dichlorosilylene. In the presence of 1,3-butadiene the main products of the reaction are the amine hydrochloride and 1,1-dichlorosilacyclopentene-3, the product of 1,4-addition of dichlorosilylene to 1,3-butadiene.     

Triallylstannyllithium-allyllithium as an initiator for the anionic reversible chain transfer polymerization of 1,3-butadiene

The anionic polymerization of 1,3-butadiene using a novel metalloidal anion initiator, triallylstannyllithium (TALi)-allyllithium (ALi), was studied. The TALi-ALi initiated anionic polymerization of 1,3-butadiene gave the star polymer along with the linear polybutadiene (PBD). The star polymer consisted of three PBD branches and a central tin atom. What is striking is a fact that the number-average molecular weights (M_n) and molecular weight distribution of three PBD branches and linear PBD were almost identical. A reversible chain transfer polymerization mechanism, which includes the equilibrium between tri(macroallyl)-stannyllithium and macroallylic anion, is proposed. © 1996 John Wiley & Sons, Inc.     

Measurement of acrolein and 1,3-butadiene in a single puff of cigarette smoke using lead-salt tunable diode laser infrared spectroscopy

Acrolein and 1,3-butadiene in cigarette smoke generally are measured using two separate analytical methods, a carbonyl derivative HPLC method for acrolein and a volatile organic compound (VOC) GC/MS method for 1,3-butadiene. However, a single analytical method having improved sensitivity and real-time per puff measurement will offer more specific information for evaluating experimental carbon filtered cigarettes designed to reduce the smoke deliveries of these constituents. This paper describes an infrared technique using two lead-salt tunable diode lasers (TDLs) operating with liquid nitrogen cooling with emissions at 958.8 cm(-1) and 891.0 cm(-1) respectively for the simultaneous measurement of acrolein and 1,3-butadiene, respectively, in each puff of mainstream cigarette smoke in real time. The dual TDL system uses a 3.1l volume, 100 m astigmatic multiple pass absorption gas cell. Quantitation is based on a spectral fit that uses previously determined infrared molecular line parameters generated in our laboratory, including line positions, line strengths and nitrogen-broadened half-widths for these species. Since acrolein and ethylene absorption lines overlap and 1,3-butadiene, ethylene and propylene absorption lines overlap, the per puff deliveries of ethylene and propylene were determined since their overlapping absorption lines must be taken into account by the spectral fit. The acrolein and 1,3-butadiene total cigarette deliveries for the 1R5F Kentucky Reference cigarette were in agreement with the HPLC and GC/MS methods, respectively. The limit of detection (LOD) for 1,3-butadiene and acrolein was 4 ng/puff and 24 ng/puff, respectively, which is more than adequate to determine at which puff they break through the carbon filter. The retention and breakthrough behavior for the two primary smoke constituents depend on the cigarette design and characteristics of the carbon filter being evaluated.     

Synthesis of chiral 1-ferrocenylaldols and 1-ferrocenyl-1,3-diols via asymmetric reductions

The asymmetric transfer hydrogenation promoted by the (R,R)-(Ts-DPEN)–Ru complex of some 1-ferrocenyl-1,3-diketones was investigated and in all the cases only the carbonyl group distant to the metallocene moiety was reduced with variable selectivity depending on the C-3 substituent. The CBS-catalyzed reduction of 1-ferrocenyl-β-hydroxy-1-ketones, previously protected as acetates, was also found effective, giving both the corresponding syn- and anti-1,3-diols in satisfactory enantiomeric purity.     

Synthesis and characterization of random or gradient butadiene-p-methylstyrene copolymers via anionic polymerization

Copolymers of 1,3-butadiene and p-methylstyrene （p-MS） were synthesized via anionic polymerization. A benzophenone-potassium complex was added to tune the reactivity ratio of the two monomers, leading to random and gradient composition alonglthe copolymer chain. The overall composition and microstructure could be controlled and well characterized by GPC and H-NMR. The p-MS was distributed from gradient to random with increasing the content of the benzophenone-potassium complex, and the 1,2-microstrucmre in the polybutadiene sequence increased at the same time. The hydrogenation of the copolymer of 1,3-butadiene and p-MS resulted in the corresponding saturated copolymer with well- defined structure and narrow molecular weight distribution.     

Photochemical transformations of 3-alkyl-3-ferrocenylcyclopropenes

Photolysis of 3-ferrocenyl-3-methyl- and 3-ferrocenyl-3-isopropylcyclopropenes was studied. Sensitized irradiation (triplet excitation) afforded [2+2]-cycloaddition products, viz., tricyclohexane derivatives. Direct irradiation (singlet excitation) of methyl-substituted ferrocenylcyclopropene gave rise to 2-ferrocenylbut-1-en-3-yne and trans-2-ferrocenylbut-2-ene. The isopropyl analog was converted into 1-ferrocenyl-4,4-dimethylcyclobutene. The reaction of this cyclopropene with 2-ferrocenyl-3-methylbut-1-ene afforded 1,3-diferrocenyl-3-isopropyl-6,6-dimethylcyclohexene. The latter compound and 3,6-diferrocenyl-3,6-diisopropyltricyclo[3.1.0.0^2,4]hexane were studied by X-ray diffraction analysis. Possible reaction pathways are discussed.     

The role of phosphine and 1,2-diimine complexes of nickel in the oxidation states 0, +1, and +2 in the catalyzed di-, oligo-, and polymerization of ethylene

The turnover frequency and number have been determined for eighteen catalytic systems based on triphenylphosphine and 1,4-diazo-1,3-butadiene complexes of nickel in the formal oxidation states 0, +1, and +2 in the oligoand polymerization of lower alkenes. The main catalytic characteristics are almost independent of the oxidation state of nickel in the precursor and depend on the nature and concentration of the cocatalyst (Lewis acid). The catalytic systems have been studied by ESR. The ESR spectral parameters are presented for nickel(I) 1,4-diazo-1,3-butadiene complexes and radical anions resulting from the reactions of the cocatalyst with nickel α-diimine complexes. Reactions describing the formation, functioning, decomposition, and regeneration of the catalytically active nickel hydride complexes are proposed.     

Unexpected reactions of ferrocene acetal derived from tartaric acid with alkyllithium: competition between proton abstraction and nucleophilic attack

We wished to prepare planar chiral compounds by the lithiation of acetal 2-ferrocenyl-(4S,5S)-bis(methoxymethyl)-1,3-dioxolane (1) with butyllithium followed by the reaction with an electrophile. However, the desired products were not observed and two unexpected products, 1-ferrocenyl-1-pentanol (4) of the nucleophilic attack product and 2-ferrocenyl-4,5-dimethylene-1,3-dioxolane (5) of the proton abstraction product, were isolated. Because the nucleophilic attack on acetal carbon is rarely reported so far and both products 4 and 5 may have some potential uses in organic synthesis, these unexpected reactions are investigated in detail. The mechanisms of these reactions are discussed.