Fluorohalogeno compounds. II. Sonochemical approach to 3,3,3-trifluoropropionic acids

Fluoropropionic acids of the general formula CF₃CXYCO₂H ( X = F, Cl, Br ; Y = F, Cl, Br, H ) were obtained by the sonochemically promoted reaction of fluorohalogenoethanes CF₃CXYZ ( Z = Cl, Br ) with zinc and carbon dioxide. Penta- and tetrafluoroethanes ( X = Y = F and X = F, respectively ) gave good yields ( 35 – 47 % ) of the acids; with trifluoro derivatives the yields were substantially lower. Hydrogenolysis of the CCl and CBr bonds in CF₃CFClCO₂H and CF₃CFBrCO₂H afforded 2,3,3,3-tetrafluoropropionic acid.     

A series of novel 2,6-bis(imino)pyridyl iron catalysts: synthesis, characterization and ethylene oligomerization

A series of novel 2,6-bis(imino)pyridyl iron complexes {2,6-(2-X-4-Y-5-ZC₆H₂NCCH₃)₂C₅H₃N}FeCl₂ (X = Cl, Y = CH₃, Z = H (2); X = Br, Y = CH₃, Z = H (3); X = F, Y = H, Z = CH₃ (4); X = Cl, Y = H, Z = CH₃ (5); X = Cl, Y = F (7)) have been synthesized and characterized with elemental analysis and IR. These iron coordinative complexes, activated with methylaluminoxane (MAO), lead to highly active ethylene oligomerization (>10⁷ g/mol Fe h) and the products are mostly linear α-olefins (>90%). The catalytic activities and product properties depend on the substituents on aryl rings and the reaction conditions. As reaction temperature increases, the catalytic activities decrease rapidly and more low-molar-mass products are produced. The product distributions are almost independent of the Al/Fe molar ratio, but the catalytic activities change in different trends when the ortho-substituents on the aryl rings are different. The other three complexes have also been synthesized for comparison to investigate the steric hindrance and electronic effect on the properties of complexes. The complex with adaptable steric hindrance and electronic properties exhibits the highest catalytic activities.     

Preparation and synthetic utility of fluorinated phosphonium salts,bisphosphonium salts and phosphoranium salts

The synthesis and mechanism of formation of phosphonium salts of the type [R₃$\text{P}\text{+}$CFXY]Z^? (where X = F, Cl, Br; Y = Br, Cl; Z = Br, Cl), $\text{bis}$-phosphonium salts of the type [R₃$\text{P}\text{+}$CF₂$\text{P}\text{+}$R₃]2Br^?, and phosphoranium salts of the type [R₃$\text{P}\text{+}$$\text{C}\text{?}$F$\text{P}\text{+}$R₃]X^? (X = Br, Cl) will be presented. The applicability of these substrates in the generation of useful nucleophilic or electrophilic synthetic intermediates will be discussed.     

Synthese von methyldihalogenarsinen CH3AsXY mit verschiedenen halogenen XY

The reactions of the methylhalogenodimethylaminoarsines CH₃As-[N(CH₃)₂]X (X  F, Cl, Br, I) with HY (Y = Cl, Br) yield the methyldihalogenoarsines CH₃AsXY. The compounds CH₃As[N(CH₃)₂]X are prepared by the reactions of CH₃AsCl₂ with HN(CH₃)₂, CH₃As[N(CH₃)₂]₂ with HX (X = Cl, Br) and by exchange reactions between CH₃As[N(CH₃)₂]₂ and CH₃AsX₂ (X = F, Cl, Br, I).     

Mass spectral correlations of halogenated 1,1,1,3,3,3-hexafluoropropanes and 1,1,1-trifluoroethanes

The mass spectral fragmentation patterns at 20 eV of twelve compounds of the type CF₃CXYCF₃ (X, Y =F, Cl, Br, I, H) and five compounds of the type CF₃ CX₂ Y (X, Y= F, Cl, Br) were analyzed. It was noted that the frequency of carbon–helogen and carbon–carbon bond cleavage was quite dependent on the substituents X and Y.     

Alkoxy,amido and thiolato complexes of tris (3, 5-dimethylpyrazolyl)borato(nitrosyl) molybdenum fluoride,chloride and bromide

The complexes Mo{HB(Me₂pyz)₃}(NO)XY {HB(Me₂pyz)₃  HB(3, 5-Me₂C₃HN₂)₃; X=Y=F, Cl or Br; X=F, Y=OEt, NHMe or SBuⁿ; X=Cl, Y=NHR (R=Me Et, Buⁿ, Ph, p-MeC₆H₄), NMe₂ and SR (R=Buⁿ, C₆H₁₁, CH₂Ph, Ph); X=Br, Y=NHMe, NMe₂ and SBuⁿ} have been prepared and characterised spectroscopically. Their properties are generally similar to those of their iodo-analogues.     

α,ω-Bis(4-substituted-3-quinolinylthio)alkanes from reactions of thioquinanthrene with alkoxides

The reaction of thioquinanthrene 1 with sodium alkoxides and α,ω-dihaloalkanes leads to the formation of α,ω-bis[4-(4-methoxy-3-quinolinylthio)-3-quinolinylthio]alkanes 4 . The yield depends on the nature of α,ω-dihalo-alkanes. The effect of α,ω-dihaloalkanes of the following types: XCH₂X (X = Cl,Br,I), X(CH₂)₂X (X = Cl,Br,I), Br(CH₂)₃Br and Br(CH₂)₆Br were studied. The preparation of 4-alkoxy-3′-(ω-bromoalkylthio)-3,4′-diquinolinyl sulfide 3 and their transformation to α,ω-bis(4-alkoxy-3-quinolinylthio)alkanes 6 were studied as well.     

New partially fluorinated epoxides by oxidation of olefins with sodium hypohalites under phase transfer catalysis

Partially fluorinated epoxides can be readily prepared by oxidation of the corresponding olefins by NaOCl (or NaOBr) under phase transfer catalysis (PTC) conditions. Oxidation of CH₂C(CF₃)₂ at 0-5 °C leads to the formation of 2,2-bis(trifluoromethyl)oxirane in 65-75% yield. (CF₃)₂CCHCH₂X (X=Cl or Br) were converted into the corresponding epoxides in 24-31% yield by the action of NaOCl and NaOBr, respectively. Baylis-Hillman adducts of fluorinated ketones and esters of acrylic acid CH₂C[C(OH)(CF₂X)Y][C(O)OR] [X=F or Cl, Y=CF₃, CF₂Cl or C(O)OCH₃ and R=CH₃ or C(CH₃)₃] were converted into α-hydroxyepoxides in 47-84% yield under action of NaOCl in the presence of PT catalyst. Oxidation of tert-butyl ester of α-trifluoromethylacrylic acid by NaOCl rapidly proceeds at ambient temperature with formation of epoxide in 75% yield. Oxidation of (C₂F₅)₂CCHC₃F₇ results in the high yield formation of trisubstituted epoxide.     

Effect of the X and Y substituents on the carbonyl bond in 4-YC<Subscript>6</Subscript>H<Subscript>4</Subscript>C(O)X compounds

Mechanistic aspects of the effect of the X and Y substituents (X = Me, H, CF₃, CN, Br, Cl, F, OH, NH₂; Y = H, NMe₂, NH₂, CN, NO₂) on the carbonyl bond in 4-YC₆H₄C(O)X compounds are discussed on the basis of the ¹³C and ¹⁷O NMR data.     

Fluorohalogeno compounds. I. The grignard reaction of some fluorohalogenoethanes

An extension of the scope of the Grignard reaction of fluorinated compounds is reported. Fluorohalogenoethanes of the general formula CF₃CXYZ ( X = F,Cl,Br ; Y,Z = Cl,Br ) were found to undergo smoothly the metal-halogen exchange reaction with alkyl- or aryl-magnesium halides at low temperature to yield organometallic compounds CF₃CXYMgHal. The Grignard compounds were reacted with a series of aldehydes and ketones to give the corresponding alcohols in good to moderate preparative yields.     

Perfluormthyl-Element-Liganden. XVII. Adduktbildung von MenE(CF3)3−n-Liganden mit BX3-Verbindungen (Me = CH3; E = P,As, Sb; n = 0–3; X = H,CH3, Hal)

Perfluoromethyl-Element-Ligands. XVII. Formation of Adducts of Me_nE(CF₃)_3?n Ligands with BX₃ Compounds (Me = CH₃; E = P, As, Sb; n = 0–3; X = H, CH₃, Hal) The ligands Me_nE(CF₃)_3?n (Me = CH₃; E = P, As, Sb; n = 0–3) have been prepared (partly using new methods) and studied by n.m.r. spectroscopy (¹H, ¹⁹F, ³¹P, ¹³C). In order to deduce their relative donor strength their reactions with the Lewis acids “BH₃”, BMe₃, BMe₃, Me₂BBr, and BX₃ (X = F, Cl, Br) have been studied. Control of adduct formation occurs by n.m.r. spectroscopy (¹H, ¹⁹F). The following series of decreasing basicity or acidity are obtained:      

Hammett Correlation in the Accelerated Formation of 2,3-Diphenylquinoxalines in Nebulizer Microdroplets

The accelerated formation of 2,3-diphenylquinoxalines in microdroplets generated in a nebulizer has been investigated by competition experiments in which equimolar quantities of 1,2-phenylenediamine, C₆H₄(NH₂)₂, and a 4-substituted homologue, XC₆H₃(NH₂)₂ [X = F, Cl, Br, CH₃, CH₃O, CO₂CH₃, CF₃, CN or NO₂], or a 4,5-disubstituted homologue, X₂C₆H₂(NH₂)₂ [X = F, Cl, Br, or CH₃], compete to condense with benzil, (C₆H₅CO)₂. Electron-donating substituents (X = CH₃ and CH₃O) accelerate the reaction; in contrast, electron-attracting substituents (X = F, Cl, Br and particularly CO₂CH₃, CN, CF₃ and NO₂) retard it. A structure–reactivity relationship in the form of a Hammett correlation has been found by analyzing the ratio of 2,3-diphenylquinoxaline and the corresponding substituted-2,3-diphenylquinoxaline, giving a ρ value of −0.96, thus confirming that the electron density in the aromatic ring of the phenylenediamine component is reduced in the rate-limiting step in this accelerated condensation. This correlation shows that the phenylenediamine acts as a nucleophile in the reaction.     

Thermodynamics of vinyl ethers—XV : Halogen-containing vinyl ethers

Thermodynamics of geometrical and prototropic isomerization reactions on some halogen-containing vinyl ethers of the types ROCH–CHX (X = Cl, Br), ROC(CH₂X)CH₂ (X = F, Cl, Br), and ROC(CHMeCl)CH₂ (R = Me, Et, Et₂CH) have been studied. In ROCH_αCH_βX the cis (or Z) isomer is thermodynamically the more stable isomer, the higher stability of the Z isomer being due to its lower enthalpy. The relative stability of the E and Z forms is, however, reversed if the α H atom is replaced by a Me group. In systems like OCCX the double-bond stabilizing ability of the halogen atom decreases in the order Cl > Br > F, in contrast to the case in haloalkenes, where the corresponding order is F > Cl > Br.     

Computational Analysis of Mesomerism in para-Substituted mer-NCN Pincer Platinum(II) Complexes,Including its Relationships with Hammett σp Substituent Parameters

Density Functional Theory studies of square-planar Pt^II pincer structures, (4-Z-NCN)PtCl ([4-Z-NCN]⁻=[4-Z-2,6-(Me₂NCH₂)₂C₆H₂-N,C,N]⁻, Z=H, NO₂, CF₃, CO₂H, CHO, Cl, Br, I, F, SMe, SiMe₃, tBu, OH, NH₂, NMe₂), enable characterisation of mesomerism for the pincer-Pt interaction. Relationships between Hammett σ_p substituent parameters of Z and DFT data obtained from NBO6 and AOMix computation are used to probe the interaction of the 5d_yz orbital of platinum with π-orbitals of the arene ring. Analogous computation for 2,6-(Me₂CH₂)₂C₆H₃Z (Z=H, CF₃, CHO, Cl, Br, I, F, SMe, SiMe₃, tBu, OH, NH₂) and (4-H-NCN)PtZ allows an estimation of the relative substituent effects of “(CH₂NMe₂)₂PtZ” on π-delocalisation in the pincer system.     

Density functional theory study on the reactions of X− with CH3SY (X,Y = F,Cl, Br,I)

Gas‐phase anionic reactions X^? + CH₃SY (X, Y = F, Cl, Br, I) have been investigated at the level of B3LYP/6‐311+G (2df,p). Results show that the potential energy surface (PES) of gas‐phase reactions X^? + CH₃SY (X, Y = Cl, Br, I) has a quadruple‐well structure, indicating an addition–elimination (A–E) pathway. The fluorine behaves differently in many respects from the other halogens and the reactions F^? + CH₃SY (Y = F, Cl, Br, I) correspond to deprotonation instead of substitution. The gas‐phase reactions X^? + CH₃SF (X = Cl, Br, I), however, follow an A–E pathway other than the last two out going steps (COM2 and PR) that proceeds via a deprotonation. The polarizable continuum model (PCM) has been used to evaluate the solvent effects on the energetics of the reactions X^? + CH₃SY (X, Y = Cl, Br, I). The PES is predicted to be unimodal in the solvents of high polarity. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007     

Darstellung und eigenschaften von und reaktionen mit metallhaltigen heterocyclen: V. Synthese,reaktionen und struktur neuartiger manganacycloalkane

The colourless, six- and seven-membered manganacycloalkanes (OC)₄$\text{MnPR}{}_2\text{OCH}{}_2\text{XC}$H₂ are obtained by reaction of Na₂[(OC)₄MnPR₂O] with the bis(triflate)alkanes (YCH₂)₂X (R = C₆H₅; X = CH₂, C(CH₃)₂, CH₂CH₂; Y = CF₃SO₃). CO or SO₂ can be inserted into the reactive MnC-σ bonds under ring expansion. Some characteristic IR and ¹H NMR data are discussed. (OC)₄$\text{MnPR}{}_2\text{OCH}{}_2\text{CH}{}_2\text{C}$H₂ crystallizes monoclinic in the space group P2₁/c with Z = 4.     

Darstellung und charakterisierung von trifluormethylthio-cyclopropanen

The reactions of dihalogenocarbenes (CX₂, X = F, Cl, Br) with CF₃SCHCH₂ or (CF₃S)₂CCH₂ yield the corresponding substituted cyclopropanes. 1,1-Dibromo-2-trifluoromethylthio- or 1,1-dibromo- 2,2-bis(trifluoromethylthio)cyclopropanes react with (nC₄H₉)₃SnH to form trifluoromethylthio - or 1,1-bis(trifluoromethylthio)cyclopropane in good yields. Physical and spectroscopic data of the new substances are provided.     

Mono- and bis-alkoxides of tris(3,5-dimethylpyrazolyl)borato molybdenum and tungsten nitrosyls

The complexes [ML^*(NO)Cl(OR)] {L^* = HB(3,5-Me₂C₃HN₂)₃; M= Mo, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2, 5, 6; M = W, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2–6; CH₂(CF₂)₃CH₂OH; CHMeCH₂CMe₂OH} and [ML^*(NO)(OR)₂] {M = Mo, R = CH₂CH₂X, X = Cl, OMe or OEt; (CH₂)_nOH, n = 2–6; M = W,R = CH₂CH₂X, X= Cl, OMe or OEt; (CH₂)_nOH, n = 2,4–6; CH₂(CF₂)₃CH₂OH} have been prepared from [ML^*(NO)Cl₂] and the appropriate alcohol in the presence of NEt₃ or NaCO₃, and have been characterized by IR, ¹H NMR and mass spectroscopy.     

Darstellung von Trifluormethylhalogen-Iodaten(I) des Typs (CH3)4N+CF3IX− (X = F,Cl, Br) und Trifluormethyltrifluormethoxyiodat(I) (CH3)4N+CF3IOCF3−

Preparation of Trifluormethylhalogen Iodate(I) Salts (CH₃)₄N⁺CF₃IX^? (X = F, Cl, Br) and Trifluormethyltrifluormethoxy Iodate(I) (CH₃)₄N⁺CF₃IOCF₃^? We describe the preparation of new trifluormethyliodate(I) salts CF₃IX^? (X = F, Cl, Br, OCF₃). (CH₃)₄N⁺CF₃ICl^? and (CH₃)₄N⁺CF₃IBr^? are obtained via addition of CF₃I with the corresponded tetramethylammonium halogenide. (CH₃)₄N⁺CF₃IOCF₃^? is synthesized by comproportionation of (CH₃)₄N⁺CF₃ICl^? with CF₃OCl under formation of Cl₂ at ?78°C. (CH₃)₄N⁺CF₃IF^? is formed either, through thermolysis of (CH₃)₄N⁺ CF₃IOCF₃^? under separation of COF₂, or reaction of CF₃I with (CH₃)₄N⁺ OCF₃^?. The thermolabile compounds have been characterized by i.r., Raman, ¹⁹F-, ¹³C NMR spectroscopy.     

Strukturen von Bis(trifluormethyl)halogeno‐ und ‐thiocyanato‐mercuraten, [Hg(CF3)2X]— (X = Br,I, SCN), und ein Vergleich der Strukturparameter der CF3‐Gruppen

Structures of Bis(trifluoromethyl)halogeno and thiocyanato Mercurates, [Hg(CF₃)₂X]^— (X = Br, I, SCN), and a Comparison of the Structural Parameters of the CF₃ Groups [(18‐C‐6)K]₂[Hg(CF₃)₂SCN]₂ (1) and [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂X]₂ (X = Br (2) , I (3) ) are prepared and their crystal structures are determined. [(18‐C‐6)K]₂[Hg(CF₃)₂SCN]₂ (1) crystallizes in the monoclinic space group P2₁/c with Z = 2, [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂Br]₂ (2) in the monoclinic space group P2₁/n with Z = 2 and [P(CH₃)(C₆H₅)₃]₂[Hg(CF₃)₂I]₂ (3) in the triclinic space group P1¯ with Z = 1. In the solid state the three compounds form dimeric anions with planar Hg₂X₂ rings. The structural parameters of the Hg(CF₃)₂ units in the till now known bis(trifluoromethyl)halogeno mercurates are compared. In all compounds one nearly symmetric and one distorted CF₃ group exist. The largest differences of the C—F bond lengths is found for [(18‐C‐6)K][Hg(CF₃)₂I]. This can be regarded as the experimental evidence for the properties of trifluoromethyl mercury compounds to act as excellent difluorocarbene sources in the presence of alkali iodides.