Reactions with Hydrophosphoryl Halides

Abstract

In the systems RPCl₂+H₂O, RPCl₂+RCOOH, RPCl₂+RPH(O)OH and RPH(O)OH+RCOX the formation of hydrophosphoryl halides RPH(O)X (X=Cl,Br,I; R=H,OH,Hal,Alk,AlkO,Ar) was proved by spectral and chemical methods. Hydrophosphoryl halides react with alyphatic ketones R′₂CO yielding phosphinic halides R[R′₂C(OH)]P(O)X (X-ray analysis). In case of aromatic aldehydes and ketones containing electron donor substituentes, the addition products are rearranged into α-halogenalkylphosphinic acids.     

Halides of Titanium in Lower Oxidation States

New investigations on the di‐ and trihalides of titanium, TiX₂ and TiX₃ (X = Cl, Br, I), with their 3d² and 3d¹ electronic configurations, confirm the early observations and conclusions of Klemm. At sufficiently low temperatures, Ti–Ti single bonds are formed in the one‐dimensional trihalides, i.e., Ti–Ti dimers are observed. Equally, in the two‐dimensional dihalides, {Ti₃} triangles occur with three single bonds. Phase transitions were detected from single‐crystal or powder X‐ray diffraction data, from magnetic measurements and thermal analysis. Except for the binary halides a number of ternary halides ATiX₃ (extended chains of facesharing octahedra), K₄Ti₃Br₁₂ (triples of face‐sharing octahedra), Na₂Ti₃Cl₈ (triangular trimers), A₃Ti₂X₉ (dimers of face‐sharing octahedra), and A₃TiX₆ (isolated octahedra) as well as the mixed‐valent halides CsTi₂I₇ (tetrahedra and octahedra) and Na₅Ti₃Cl₁₂ (chains of octahedra) have been observed. Except for the triangles in titanium(II) halides, cluster compounds are rare but include K₄[{OTi₄}I₁₂] and {CTi₆}Cl₁₄.     

Ruthenium-Catalyzed Coupling Reaction of Benzylic Halides

Abstract

Reported herein is a novel method on dechlorination coupling reaction of halides by using RuCl₂(PPh₃)₃ catalyst under a hydrogen atmosphere with benzene as the solvent, which affords alkanes in excellent yields.     

Exploration of Chiral Organic–Inorganic Hybrid Semiconducting Lead Halides

Organic–inorganic lead halides have recently emerged as promising alternatives to conventional optoelectronic materials, considering their intriguing physical properties. However, organic–inorganic lead halides featuring chirality are seldom explored. Here, a pair of enantiomorphic organic–inorganic hybrid semiconducting lead halides, (R‐C₅H₁₄N₂)PbBr₄ ( 1R ) and (S‐C₅H₁₄N₂)PbBr₄ ( 2S ), were successfully obtained with the templating of chiral amines. These compounds adopt distinct one‐dimensional infinite quantum helices formed by edge‐shared transformative lead bromide octahedra. Notably, 1R and 2S present mirror circular dichroism (CD) signals due to the chirality transfer of the enantiopure amines. Furthermore, 1R and 2S exhibit phase‐matchable quadratic nonlinear response and typical semiconducting behaviours. This work highlights the potential of lead halides as a new kind of chiral semiconducting materials in spintronic and chiral optical applications.     

Crucial Role of Water in the Mechanosynthesis of CsPbI3 and Other ABX3 Halides

Mechanochemical synthesis of CsPbI₃, as a model system for ABX₃ halides, was studied. Water was shown to strongly promote the kinetics of formation of CsPbI₃ from the CsI+PbI₂ mixture through increased mobility of the constituting ionic species. Since many binary and ternary halides are hygroscopic, it was concluded that the presence of small, uncontrollable and unintentional additions of water should often occur in both precursor mixtures and synthesized complex halides boosting the kinetics of formation of many, if not all, ternary organic–inorganic hybrid halides such as, for example, MAPbX₃ (X=Cl, Br, I). In addition, trace amounts of water should influence the transport characteristics of complex halides. Thus, the presence of water explains, at least partially, the huge scatter in both the reported mechanochemical reaction times necessary for obtaining single-phase APbX₃ perovskite halides and the activation energies of ionic diffusion in APbX₃.     

Contributions to the Mechanism of Isobutene Polymerization. VI. Effect of Halides

The effects of various allyl chlorides and alkyl halides on the overall yield of polymerization and molecular weight of polyisobutene have been investigated and expressed quantitatively by poison and transfer coefficients. The poison and transfer coefficients of halides have been compared with those obtained previously for corresponding hydorcarbons. The poison coefficients of halides and hydrocarbons can be treated formally in a similar manner (1/W_p vs. [X] plots linear for both classes); however, the appropriate transfer coefficients indicate fundamentally dissimilar transfer mechanisms in these systems (1/MW_p vs. [X] plots linear for hydrocarbons, whereas 1/MW_p vs. [X]^1/2 plots linear for halides). These results are discussed in terms of the allylic termination mechanism.     

Clathrate Hydrates of Tetrabutylammonium and Tetraisoamylammonium Halides

Clathrate formation was considered for two series of systems: (C₄H₉)₄NG–H₂O and iC₅H₁₁)₄NG–H₂O G = F^-, Cl^-, Br^-, I^-). Clathrate hydrates of tetraisoamylammonium halides were shown to melt at higher temperatures than those of the butyl series. In passing from fluoride to bromide, the stability of compounds of the butyl series falls significantly and tetrabutylammonium iodide does not produce polyhydrates. In the isoamyl series, the melting points of polyhydrates vary insignificantly for different halides. In addition, the highest melting hydrate of tetraisoamylammonium bromide melts at a slightly higher temperature than chloride hydrates, indicating not only a hydrophilic effect of the anion on clathrate formation.     

On the Reactions of Trithiophosphites with Alcohols in the Presence of Transition Metal Halides

Abstract

Recently we have established that triphenyl- and trialkyltrithiophos-phites react with copper(1) halides with the formation of different typcs of occupies depending on substituents in the thioalkylgmup and on the conditions. Thesc complexes readily react with alcohols Rsulting in dialkylphosphorous acid [I]. We have assumed that the analogous phosphorylation of alcohols by (PhS), P and (AlkS)3P must be conducted in the presence of transition metal halides (CuCI, CuBr, CdCI₂, CdI₂, ZnC1₂, HgCl₂, HgBr₂) as well.     

Microscopic Reactivity of Phenylferrate Ions toward Organyl Halides

Despite its practical importance, organoiron chemistry remains poorly understood due to its mechanistic complexity. Here, we focus on the oxidative addition of organyl halides to phenylferrate anions in the gas phase. By mass-selecting individual phenylferrate anions, we can determine the effect of the oxidation state, the ligation, and the nuclearity of the iron complex on its reactions with a series of organyl halides RX. We find that Ph₂Fe(I)⁻ and other low-valent ferrates are more reactive than Ph₃Fe(II)⁻; Ph₄Fe(III)⁻ is inert. The coordination of a PPh₃ ligand or the presence of a second iron center lower the reactivity. Besides direct cross-coupling reactions resulting in the formation of RPh, we also observe the abstraction of halogen atoms. This reaction channel shows the readiness of organoiron species to undergo radical-type processes. Complementary DFT calculations afford further insight and rationalize the high reactivity of the Ph₂Fe(I)⁻ complex by the exothermicity of the oxidative addition and the low barriers associated with this reaction step. At the same time, they point to the importance of changes of the spin state in the reactions of Ph₃Fe(II)⁻.     

Samarium-Catalyzed Electrochemical Reduction of Organic Halides

Electroreduction of a series of organic halides including chloro- and fluoroderivatives bearing various functional groups is effected in good yields in the presence of a catalytical amount of SmCl_3. Reactions are carried out in DMF in a single-compartment cell fitted with a consumable magnesium anode.     

Oxidative Halogenation of Aromatic Compounds with Metal Halides and Sodium Bismuthate

A new mild and efficient method for aromatic halogenation with a wide variety of halides in the presence of sodium bismuthate NaBO₃ in AcOH is reported. Metal halides of groups Ia, IIa, IIIa, IVa, Va, and the first row of transition elements are suitable for this method.     

Synthesis of CuI Trifluoromethylselenates for Trifluoromethylselenolation of Aryl and Alkyl Halides

The development of new strategies for synthesis of trifluoromethylthiolate compounds is of considerable importance in pharmaceuticals, agrochemicals, and advanced materials. Accordingly, currently much attention is being devoted to the development of effective methods and reagents for their synthesis. In contrast, considerably less effort has been afforded to the development of preparing C?SeCF₃ bonds. Herein we report a concise route to synthesize a family of copper(I) trifluoromethylselenolate reagents by the reaction of CuI with the Ruppert’s reagent (Me₃SiCF₃), KF, and elemental selenium in the presence of dinitrogen ligands in CH₃CN at room temperature. The reagent [Cu(bpy)(SeCF₃)]₂ was proven to be air‐stable and highly efficient for nucleophilic trifluoromethylthselenolation of a broad range of (hetero)aryl halides and alkyl halides. This method represents a powerful protocol for the construction trifluoromethylselenolate compounds.     

Reactions of O2 --Containing Supramolecules with Alkyl Halides

Formation of O₂ ^--containing supramolecules generated from the system 18-crown-6-KO₂ and electrochemically (tetraethylammonium superoxide) and the kinetics of the reactions of the generated O₂ ^- with alkyl halides in acetonitrile were studied conductometrically and UV-spectrophotometrically; the kinetic parameters of the processes were determined. The E2 mechanism was suggested for the reaction.     

Nickel Mediated Conversion of Acyl Halides in Aldehydes

Aldehydes are obtained from acyl halides employing stoichiometric tri n.butyl tin hydride (TBTH) and catalytic nickeldiphenylphosphinoethane dichloride (NidppeCl₂), at room temperature. © 1997 Elsevier Science Ltd.     

钯催化卤代芳烃的胺化反应研究

钯催化卤代芳烃胺化是形成Car-N的重要方法.配体的发展扩展了底物的适用范围, 提高了反应的选择性,实现了廉价易得的氯代芳烃的胺化,弱碱的使用提高了官能团的兼 容性,因此Pd催化芳胺化广泛应用于合成芳胺类化合物.本文以卤代芳烃为线索,对钯催化偶联胺化反应的研究进展进行了综述和展望.     

Doped Zero-Dimensional Cesium Zinc Halides for High-Efficiency Blue Light Emission

All-inorganic zero-dimensional (0D) metal halides have recently received increasing attention due to their excellent photoluminescence (PL) performance and high stability. Herein, we present the successful doping of copper(I) into 0D Cs₂ZnBr₄. The incorporating of Cu⁺ cations enables the originally weakly luminescent Cs₂ZnBr₄ to exhibit an efficient blue emission centered at around 465 nm, with a high photoluminescence quantum yield (PLQY) of 65.3 %. Detailed spectral characterizations, including ultrafast transient absorption (TA) techniques, were carried out to investigate the effect of Cu⁺ dopants and the origin of blue emission in Cs₂ZnBr₄:Cu. To further study the role of the A-site cation and halogen, A₂ZnCl₄:Cu (A=Cs, Rb) were also synthesized and found to generate intense sky-blue emission (PLQY≈73.1 %). This work represents an effective strategy for the development of environmentally friendly, low-cost and high-efficiency blue-emitting 0D all-inorganic metal halides.     

Reductive Buchwald-Hartwig Amination of Nitroarenes with Aryl (pseudo)Halides

De novo catalytic syntheses of diarylamines from a palladium-catalyzed reductive Buchwald-Hartwig amination of nitroarenes with aryl (pseudo)halides is described. The exquisite use of upstream nitroarenes as arylamine surrogates, the judicious selection of bis(pinacolato)diboron (B₂pin₂) as a stoichiometric reducing agent, and wide substrate scope including (hetero)aryl halides (Cl, Br and I) and aryl triflates, constitute the striking features of the current protocol. Moreover, application of this technique to the syntheses of advanced intermediates and active pharmaceutical ingredients also proved successful, thus providing an alternative step-economical approach to the syntheses of diarylamine-incorporated molecules. Preliminary mechanistic investigation demonstrates that an amine and a nitrosoarene intermediates might be involved in this reductive event.     

Homolytic versus Heterolytic Dissociation of Alkalimetal Halides: The Effect of Microsolvation

Herein we report density functional calculations of homolytic and heterolytic dissociation energies of the diatomic alkalimetal halides MX (M=Li, Na, K, Rb, and Cs and X=F, Cl, Br, I, and At) and their corresponding microsolvated structures MX?(H₂O)_n (n=1 to 4). Our results show that the homolytic dissociation energy of the MX?(H₂O)_n species increases with the number of water molecules involved in the microsolvated salts. On the other hand, the heterolytic dissociation energy follows exactly the opposite trend. As a result, while for the isolated diatomic alkalimetal halides, homolytic dissociation is always favored over heterolytic dissociation, the latter is preferred for CsF and CsCl already for n=2, and for n=4 it is the preferential mode of dissociation for more than half of the species studied.     

Hydrodehalogenation of Aryl Halides through Direct Electrolysis

A catalyst- and metal-free electrochemical hydrodehalogenation of aryl halides is disclosed. Our reaction by a flexible protocol is operated in an undivided cell equipped with an inexpensive graphite rod anode and cathode. Trialkylamines nBu₃N/Et₃N behave as effective reductants and hydrogen atom donors for this electrochemical reductive reaction. Various aryl and heteroaryl bromides worked effectively. The typically less reactive aryl chlorides and fluorides can also be smoothly converted. The utility of our method is demonstrated by detoxification of harmful pesticides and hydrodebromination of a dibrominated biphenyl (analogues of flame-retardants) in gram scale.