Synthesis and Characterization of Poly(hydrogen halide) Halogenates (–I)

Herein, we report the synthesis and characterization of a variety of novel poly(hydrogen halide) halogenates (−I). The bifluoride ion, which is known to have the highest hydrogen bond energy of ≈160 kJ mol⁻¹, is the most famous among many examples of [X(HX)_n]⁻ anions (X=F, Cl) known in the literature. In contrast, little is known about poly(hydrogen halide) halogenates containing two different halogens, ([X(HY)_n]⁻). In this work we present the synthesis of anions of the type [X(HY)_n]⁻ (X=Br, I, ClO₄; Y=Cl, Br, CN) stabilized by the [PPh₄]⁺ and [PPN]⁺ cation. The obtained compounds have been characterized by single-crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations. In addition, the behavior of halide ions in hydrogen fluoride was investigated by using experimental and quantum-chemical methods in order to gain knowledge on the acidity of hydrogen halides in HF.     

Principles and design of living cationic polymerization of vinyl monomers: The nature of the growing species based on in-situ 1H NMR analysis

This paper focuses on in-situ ¹H NMR analysis of model reactions that are directed to clarify the nature of the growing species in the following three classes of living cationic polymerization based on the stabilization of the growing carbocations with nucleophilic counteranions and added salts: (a) Vinyl ethers/HCl/SnCl₄/added nBu4N+Y-; (b) Vinyl ethers/HX/ZnCl₂ (salt free); (c) Styrene/HX/SnCl₄/added nBu4N+Y- (X and Y: halogen) Through the NMR analysis, system (a) provides evidence for the generation of carbocations from adducts [CH₃CH(OR)Cl] of vinyl ethers and hydrogen chloride and also for the suppression of such ionic species by the added salts. For systems (b) and (c) the spectroscopic observation demonstrated rapid counteranion exchanges in the growing species, indicating that upon reacting with a monomer the living end assumes an ionic character.     

Structure and stability of oligomeric anions [M n X3 n + 1]? (M = Al, Ga, In; X = F, Cl, Br, I; n = 2–4): A quantum-chemical study

The structural and thermodynamic properties of oligomeric anions [M _n X_{3n+ 1}]⁻ (M = Al, Ga, In; X = F, Cl, Br, I; n = 2, 3, 4) have been obtained by the density functional theory B3LYP method with the LAN2DZ(d) and LAN2DZ(d)+ basis sets. A wide diversity of structural isomers was found for trimeric fluoride anions M₃F₁₀⁻. Among the trimers, except In₃F₁₀⁻, the most stable is a linear isomer composed of two MX₃ molecules coordinated to the MX₄⁻ anion. The formation of tetrameric anions M₄X₁₃⁻ was demonstrated to be thermodynamically allowed at low temperatures at MX₃: X⁻ > 4: 1. The existence of higher oligomers is less probable. The affinity of oligomer halides (MX₃) _n for halide ions increases with an increase in n. The propensity to form oligomeric anions decreases in the series F > Cl ≥ Br > I. The fluoride systems show a tendency to form structures with CN = 5 and 6, these structures for In being the most stable. Original Russian Text ? A.Yu. Timoshkin, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 1, pp. 87–100.     

Structural correlations of the lanthanide halides and related compounds. Derivatives of the anti-nickel-arsenide structure

An examination of structural data for lanthanide halides and related compounds has shown that a substantial number of different structure types are conveniently described as layered structures derived from anti-NiAs by removal or shear of cation layers and distortion of the residual layers. The structural correlations of various MX, MX_1.5, MX₂, MXY, MX₃, and MX₂Y compositions (M = cation, X and Y = anions) are described by the presentation of a subgroup-supergroup diagram relating their space groups and by comparison of their structural projections. A close relationship between the CsCl- and NiAs-type structures is observed. The occurrence of displacive and order-disorder phase transitions, the formation ternary derivatives by ion accommodation processes and the possible formation of intermediate halides, M₂X_2n+1, by coherent intergrowth of MX₂ and MX₃ structures are discussed. The effects of radius ratio and cation coordination number on the stabilities of halide structures and on the formation of complex MX₂ layers derived from hexagonal-closest-packed metal arrays are examined.     

Structural relationships,crystal chemistry and anion substitution processes for M(III)X3 systems of the lanthanides and actinides

An examination of data for lanthanide and actinide phases with UCl₃-type and PuBr₃-type M(III)X₃ structures has shown that these systems are conveniently described by alternating layers of [MX₂]ⁿ⁺_n and [X]^n?_n. The relationships between the UCl₃- and PuBr₃-type structures are described and expanded to include a variety of anion substitution systems, M(III)X_3?xY_x. The two different types of [MX₂]ⁿ⁺_n layers observed in these systems are consistent with the existence of a novel structural unit, [M₂X₄]²⁺. The effects of radius ratio constraints and layering mechanisms on the phase equilibria and anionic substitution processes, polymorphism and crystal growth in the MX_3?xY_x systems are discussed.     

M/Xn (MAl,Mg; XBr,I) batteries based on anion transport mechanism

A new type of electrochemical storage energy batteries of M/X_n (MAl, Mg; XBr, I, n = 3, 2) were found. They can operate with nonaqueous electrolyte or solid electrolyte showing high voltage and moderate rate performances. The discharging mechanism is related to the formation and growth of the electrolyte phase MX_n on the surface of M electrode. The MX_n phase is X⁻ conductor and X⁻ anions play the transport role in electrode and electrolyte in these systems. Our finding shows that anion-conducting electrochemical batteries can be also promising for energy storage compared to cation-conducting systems in current batteries.     

Characterization of the new series of quasi one-dimensional compounds(MX4)nY (M =Nb,Ta; X =S,Se; Y =Br,I)

A detailed investigation on the new series of compounds(MX₄)_nY (M =Nb, Ta; X =S, Se; Y =Br, I)is given through structural information and resistivity measurements. All these compounds are built with the same framework which is composed ofMX₄chains and halogen atoms between these chains. It is found that the resistivity behavior is closely related to the metal-metal sequence along theMX₄chain.     

A Study of Magnetic Relaxation in Dysprosium(III) Single-Molecule Magnets

Although the development of single-molecule magnets (SMMs) is rapid, there are only two families of high energy barrier (U_eff) dysprosium(III) SMMs known so far: the cyclopentadienyl (Cp) family with a sandwich structure and the pentagonal-bipyramidal (PB) family with D_5h symmetry. These high-barrier SMMs, which usually possess U_eff>500 cm⁻¹ allow the separate study of the four magnetic relaxation paths, namely, direct, quantum tunnelling, Raman and Orbach processes, in detail. Whereas the first family is chemically more challenging to modify the Cp rings, it is shown herein that the latter family, with the common formulae [DyX¹X²(L_eq)₅]⁺, such as X¹/X²=⁻OCMe₃, ⁻OSiMe₃, ⁻OPh, Cl⁻ or Br⁻; L_eq=THF/pyridine/4-methylpyridine, can be readily fine-tuned with a range of axial and equatorial ligands by simple substitution reactions. This allows unambiguous confirmation that the U_eff mainly depends on the identity of X¹ and X², rather than on L_eq. More importantly, the fitted parameters are barrier dependent. If X¹ is an O donor and X² is a halide, 500<U_eff<600 cm⁻¹, log τ_0avg (s)=−10.66, log C_avg (s⁻¹ K⁻ⁿ)= −5.05, n_avg=4.1 and T_H=9 K (in which τ₀ is the pre-exponential factor for the Orbach relaxation process, C and n are parameters used to describe Raman relaxation, and T_H is the highest temperature at which magnetic hysteresis is observed). For cases in which both X¹ and X² are O donors, 900<U_eff<1300 cm⁻¹, log τ_0avg (s)=−11.63, log C_avg (s⁻¹ K⁻ⁿ)= −6.03, n_avg=4.1 and 18<T_H<25 K. Based on these results, it can be further concluded that U_eff not only has a linear correlation to the axial Dy−X bond lengths, but also to T_H for these PB SMMs. This represents the first systematic study of a family of lanthanide SMMs and derives the first magneto-structural correlation in Dy SMMs.     

Far-infrared and Raman spectra ofpseudo-tetrahedral complexes of ethylenedimorpholene

Summary The far-i.r. and Raman spectra of a closely related group ofpseudo-tetrahedral complexes of general formula [MX₂EDM] are reported (M = Co^II, Ni^II, Cu^II, Zn^II; X = Cl or Br). EDM, ethylenedimorpholene, acts in these compounds as a bidentate nitrogen donor. The main skeletal vibrations are assigned under the approximate symmetry of theC _2v (MX₂Y₂) point group.     

Two isomorphous azastilbene derivatives: 1‐(2‐chlorobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium chloride and 1‐(2‐bromobenzyl)‐4‐[(E)‐2‐(4‐hydroxyphenyl)ethenyl]pyridinium bromide

The crystal structures of the two title (E)‐stilbazolium halogenates, C₂₀H₁₇ClNO⁺·Cl⁻ and C₂₀H₁₇BrNO⁺·Br⁻, are isomorphous, with an isostructurality index of 0.985. The azastyryl fragments are almost planar, with dihedral angles between the benzene and pyridine rings of ca 4.5°. The rings of the benzyl groups are, in turn, almost perpendicular to the azastyryl planes, with dihedral angles larger than 80°. The cations and anions are connected by O—H...X⁻ (X = halogen) hydrogen bonds. The halide anions are `sandwiched' between the charged pyridinium rings of neighbouring molecules, and weak C—H...O hydrogen bonds and C—H...X and C—H...π interactions also contribute to the crystal structures.     

Photoinitiated cationic polymerization with triarylsulfonium salts

Triarylsulfonium salts Ar₃S⁺MX_n⁻ with complex metal halide anions such as BF₄⁻, AsF₆⁻, PF₆⁻, and SbF₆⁻ are a new class of highly efficient photoinitiators for cationic polymerization. In this article we describe several synthetic routes to the preparation of these compounds along with their physical and spectroscopic properties. Mechanistic studies have shown that when these compounds are irradiated at wavelengths of 190–365 nm carbon-sulfur bond cleavage occurs to form radical fragments. At the same time the strong Brϕnsted acid HMX_n, which is the active initiator of cationic polymerization that takes place in subsequent “dark” steps, is also produced. A study of the parameters that affect the photolysis of triarylsulfonium salts is reported with a measurement of the absolute quantum yields. The cationic polymerizations of four typical monomers—styrene oxide, cyclohexene oxide, tetrahydrofuran, and 2-chloroethyl vinyl ether—with triarylsulfonium salt photoinitiators are described.     

Rate constants for the reactions of OH radicals and Cl atoms with Di‐n‐Propyl ether and Di‐n‐Butyl ether and their deuterated analogs

Using relative rate methods, rate constants for the gas‐phase reactions of OH radicals and Cl atoms with di‐n‐propyl ether, di‐n‐propyl ether‐d₁₄, di‐n‐butyl ether and di‐n‐butyl ether‐d₁₈ have been measured at 296 ± 2 K and atmospheric pressure of air. The rate constants obtained (in cm³ molecule⁻¹ s⁻¹ units) were: OH radical reactions, di‐n‐propyl ether, (2.18 ± 0.17) × 10⁻¹¹; di‐n‐propyl ether‐d₁₄, (1.13 ± 0.06) × 10⁻¹¹; di‐n‐butyl ether, (3.30 ± 0.25) × 10⁻¹¹; and di‐n‐butyl ether‐d₁₈, (1.49 ± 0.12) × 10⁻¹¹; Cl atom reactions, di‐n‐propyl ether, (3.83 ± 0.05) × 10⁻¹⁰; di‐n‐propyl ether‐d₁₄, (2.84 ± 0.31) × 10⁻¹⁰; di‐n‐butyl ether, (5.15 ± 0.05) × 10⁻¹⁰; and di‐n‐butyl ether‐d₁₈, (4.03 ± 0.06) × 10⁻¹⁰. The rate constants for the di‐n‐propyl ether and di‐n‐butyl ether reactions are in agreement with literature data, and the deuterium isotope effects are consistent with H‐atom abstraction being the rate‐determining steps for both the OH radical and Cl atom reactions. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 425–431, 1999     

Secondary interactions in the iso­morphous compounds 2,6‐bis­(chloro­methyl)­pyridinium chloride and 2,6‐bis­(bromo­methyl)­pyridinium bromide

The title compounds, C₇H₈Cl₂N⁺·Cl⁻ and C₇H₈Br₂N⁺·Br⁻, are isomorphous. In the crystal packing, layers parallel to the ac plane are formed by a classical N⁺—H⋯X⁻ hydrogen bond (X = halogen) and two X⋯X contacts. A third X⋯X contact links the layers, and a fourth, which is however very long, completes a ladder‐like motif of halogen atoms. Hydro­gen bonds of the form C—H⋯X play at best a subordinate role in the packing.     

Centimeter-Sized Single Crystal of Two-Dimensional Halide Perovskites Incorporating Straight-Chain Symmetric Diammonium Ion for X-Ray Detection

Two-dimensional (2D) AA′_n−1M_nX_3n+1 type halide perovskites incorporating straight-chain symmetric diammonium cations define a new type of structure, but their optoelectronic properties are largely unexplored. Reported here is the synthesis of a centimeter-sized AA′_n−1M_nX_3n+1 type perovskite, BDAPbI₄ (BDA=NH₃C₄H₈NH₃), single crystal and its charge-transport properties under X-ray excitation. The crystal shows a staggered configuration of the [PbI₆]⁴⁻ layers, a band gap of 2.37 eV, and a low trap density of 3.1×10⁹ cm⁻³. The single-crystal X-ray detector exhibits an excellent sensitivity of 242 μC Gy_air⁻¹ cm⁻² under the 10 V bias (0.31 V μm⁻¹), a detection limit as low as 430 nGy_air s⁻¹, ultrastable response current, a stable baseline with the lowest dark current drift of 6.06×10⁻⁹ nA cm⁻¹ s⁻¹ V⁻¹, and rapid response time of τ_rise=7.3 ms and τ_fall=22.5 ms. These crystals are promising candidates for the next generation of optoelectronic devices.     

Metal Halide Regulated Photophysical Tuning of Zero-Dimensional Organic Metal Halide Hybrids: From Efficient Phosphorescence to Ultralong Afterglow

The photophysical tuning is reported for a series of tetraphenylphosphonium (TPP) metal halide hybrids containing distinct metal halides, TPP₂MX_n (MX_n=SbCl₅, MnCl₄, ZnCl₄, ZnCl₂Br₂, ZnBr₄), from efficient phosphorescence to ultralong afterglow. The afterglow properties of TPP⁺ cations could be suspended for the hybrids containing low band gap emissive metal halide species, such as SbCl₅²⁻ and MnCl₄²⁻, but significantly enhanced for the hybrids containing wide band gap non-emissive ZnCl₄²⁻. Structural and photophysical studies reveal that the enhanced afterglow is attributed to stronger π–π stacking and intermolecular electronic coupling between TPP⁺ cations in TPP₂ZnCl₄ than in the pristine organic ionic compound TPPCl. Moreover, the afterglow in TPP₂ZnX₄ can be tuned by controlling the halide composition, with the change from Cl to Br resulting in a shorter afterglow due to the heavy atom effect.     

Transition Metal Halide Salts of 1,3-bis(4-Pyridyl)propane: Synthesis and Structural Characterization

The resulting salts of (H₂bpp)MX₄ · n H₂O (M = Zn, X = Cl, n = 1, 1; M = Cd, X = Br, n = 0, 2; M = Hg, X = Cl, n = 1, 3; M = Cu, X = Cl, n = 0, 4; M = Cu, X = Br, n = 1, 5; M = Pt, X = Cl, n = 1, 6) were crystallized from the reaction mixture prepared by adding MX₂ to the HX solution of 1,3-bis(4-pyridyl)propane (bpp), while the salt of colorless (H₂bpp)SnCl₆, 7, was crystallized from the reaction mixture prepared by adding SnCl₂ to the HCl solution of bpp. Their structures have been determined by X-ray crystallography. All the compounds show supramolecular structures in the solid state by intermolecular hydrogen bondings and aromatic – interactions. The H₂bpp²⁺ cations in these metal salts adopt the gauche–gauche and anti–anti conformations with different dihedral angles for the two pyridyl rings.     

Anionic polymerization of methyl methacrylate initiated with lithium diphenylamide (Ph2NLi) in the presence of divalent transition metal halide

Anionic polymerization of methyl methacrylate (MMA) in the presence of divalent transition metal halide (MX₂ = FeBr₂, MnCl₂, CoCl₂, NiBr₂) was investigated. Initiating systems with various combinations of MX₂, lithium diphenylamide (Ph₂NLi), and organolithium (RLi, where R = nBu, Me) were effective to giving a high yield of poly(methyl methacrylate)s (PMMAs) at ?78 °C in toluene. The tacticity of the resulting PMMAs was highly dependent on the combination of the reagents used for the generation of the initiating systems within a syndiotactic (rr = 59%) to isotactic (mm = 65%) range. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 31–37, 2004     

Triangular Halogen Bond and Hydrogen Bond Supramolecular Complex Consisting of Carbon Tetrabromide,Halide, and Solvent Molecule： A Theoretical and Spectroscopic Study

The theoretical calculation and spectroscopic experiments indicate a kind of triangular three bonding supramolecular complexes CBr4…X^-…-H-C, which consist of carbon tetrabromide, halide, and protic solvent molecule （referring to dichloromethane, chloroform and acetonitrile）, can be formed in solution. The strength of halogen and hydrogen bonds in the triangular complexes using halide as common acceptor obeys the order of iodide〉bromide〉chloride. The halogen and hydrogen bonds work weak-cooperatively. Charge transfer bands of halogen bonding complexes between CBra and halide are observed in UV-Vis absorption spectroscopy in three solvents, and then the stoichiometry of 1：1, formation constants K and molar extinction coefficients ε of the halogen bonding complexes are obtained by Benesi-Hildebrand method. The K and ε show a dependence on the solvent dielectric constant and, on the whole, obey an order of iodide〉bromide〉chloride in the same solvents. Furthermore, the C-H vibrational frequencies of solvent molecules vary obviously with the addition of halide, which indicates the C-H…X- interaction. The experimental data indicate that the halogen bond and hydrogen bond coexist by sharing a common halide acceptor as predicted by calculation.     

THE PHENOMENON OF CONGLOMERATE CRYSTALLIZATION. PART 54. THE CRYSTALLIZATION MODES OF FIVE NEW COMPLEXES [TRANS-(3,2,3-TET)Co(III)X 2]Y,X=NO− 2, CN−, NCS−

Abstract

A few complexes of formula [trans-Co(N₄)X ₂]Y, where X = a monodentate ligand, N₄ = a tetraamine ligand and Y = a halide or oxy anion have been found to crystallize as conglomerates; however, the majority crystallize as racemates. The complexes are of such variety of composition and packing characteristics that it is difficult to ascertain why they crystallize in one form or the other. We decided to investigate a series of [trans-Co(N₄)X ₂]Y compounds in which the amine was kept constant in order to limit the variables that affect the outcome.

Five different compounds of composition [trans-Co(3,2,3-tet)X ₂]Y (3,2,3-tet = 1,10-diamino-4,7-diaza-decane, X = NO^? ₂, CN^?, SCN^?, and Y = BF^? ₄, Cl^?, Br^?, I^?) were prepared and their crystallization behavior examined by determining their crystal structures. In all cases, when crystallized from deionized water at 21°C, these substances are racemates. Suggestions regarding this crystallization mode are offered in the discussion.