β‐Pyridinium di­chloro­iodide

The β modification of pyridinium di­chloro­iodide, C₅H₆N⁺·Cl₂I^?, was obtained as yellow crystals by the reaction of (C₅NH₅)AuCl₃, C₅H₆N⁺·Cl^? and I₂ in a vacuum‐sealed ampoule. The di­chloro­iodide ion is nearly symmetric and linear with I—Cl bond lengths of 2.544 (3) and 2.550 (3) Å and a Cl—I—Cl angle of 179.68 (12)°.     

Impact of the anion and chalcogen on the crystal structure and properties of 4,6‐dimethyl‐2‐pyrimido(thio)nium halides

By the reaction of urea or thiourea, acetylacetone and hydrogen halide (HF, HBr or HI), we have obtained seven new 4,6‐dimethyl‐2‐pyrimido(thio)nium salts, which were characterized by single‐crystal X‐ray diffraction, namely, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium bifluoride, C₆H₉N₂O⁺·HF₂^? or (dmpH)F₂H, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium bromide, C₆H₉N₂O⁺·Br^? or (dmpH)Br, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium iodide, C₆H₉N₂O⁺·I^? or (dmpH)I, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium iodide–urea (1/1), C₆H₉N₂O⁺·I^?·CH₄N₂O or (dmpH)I·ur, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium bifluoride–thiourea (1/1), C₆H₉N₂S⁺·HF₂^?·CH₄N₂S or (dmptH)F₂H·tu, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium bromide, C₆H₉N₂S⁺·Br^? or (dmptH)Br, and 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium iodide, C₆H₉N₂S⁺·I^? or (dmptH)I. Three HCl derivatives were described previously in the literature, namely, 4,6‐dimethyl‐2‐oxo‐2,3‐dihydropyrimidin‐1‐ium chloride, (dmpH)Cl, 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium chloride monohydrate, (dmptH)Cl·H₂O, and 4,6‐dimethyl‐2‐sulfanylidene‐2,3‐dihydropyrimidin‐1‐ium chloride–thiourea (1/1), (dmptH)Cl·tu. Structural analysis shows that in 9 out of 10 of these compounds, the ions form one‐dimensional chains or ribbons stabilized by hydrogen bonds. Only in one compound are parallel planes present. In all the structures, there are charge‐assisted N⁺—H…X^? hydrogen bonds, as well as weaker C_Ar⁺—H…X^? and π⁺…X^? interactions. The structures can be divided into five types according to their hydrogen‐bond patterns. All the compounds undergo thermal decomposition at relatively high temperatures (150–300 °C) without melting. Four oxopyrimidinium salts containing a π⁺…X^?…π⁺ sandwich‐like structural motif exhibit luminescent properties.     

Hydrogen‐bonding one‐dimensional chains containing the R42(8) motif in the ammonium salts 1‐naphthylammonium iodide and naphthalene‐1,8‐diyldiammonium diiodide

In 1‐naphthylammonium iodide, C₁₀H₁₀N⁺·I⁻, and naphthalene‐1,8‐diyldiammonium diiodide, C₁₀H₁₂N₂²⁺·2I⁻, the predominant hydrogen‐bonding pattern can be described using the graph‐set notation R₄²(8). This is the first report of a structure of a diprotonated naphthalene‐1,8‐diyldiammonium salt.     

1,4‐Dimethyl‐1,4‐diazo­nia­bicyclo­[2.2.2]octane diiodide acetonitrile solvate

In the crystal structure of the title compound, C₈H₁₈N₂²⁺·2I⁻·CH₃CN, the dication lies on a mirror plane containing the mol­ecular dication threefold axis. The structure displays C—H⋯I inter­actions between H atoms of the 1,4‐dimethyl‐1,4‐diazo­nia­bicyclo­[2.2.2]octane dication and the iodide anions. The H⋯I distances are in the range 2.96–3.18 (4) Å. The dications pack forming channels along the b axis, which contain the iodide anions and acetonitrile solvent mol­ecules.     

Interaction of thiamine with anions in the triclinic form of thiamine iodide: 3‐[(4‐amino‐2‐methylpyrimidin‐5‐yl)methyl]‐5‐(2‐hydroxyethyl)‐4‐methyl‐1,3‐thiazol‐3‐ium iodide 1.25‐hydrate

The asymmetric unit of the title compound, C₁₂H₁₇N₄OS⁺·I⁻·1.25H₂O, contains two crystallographically independent molecules. Both formula units assume the usual F conformation and have the hydroxyethyl group disordered over two sites, each with half occupation. Two thiamine cations are linked by hydrogen bonds into a cyclic dimer. These dimers are further connected by base‐pairing hydrogen bonds into a chain along [010]. The stacked dimers form channels, which are occupied by iodide anions. The cations and anions are associated by N—H...I hydrogen bonds, C—H...I interactions and I...thiazolium ring close contacts. The interactions between thiamine and the iodide anions are similar to those observed in monoclinic thiamine iodide 1.5‐hydrate [Hu & Zhang (1993). J. Inclusion Phenom. Mol. Recognit. Chem. 16 , 273–281].     

Metal Derivatives of Heterocyclic Thioamides: Synthesis and Crystal Structures of Copper Complexes with 1‐Methyl‐1,3‐imidazoline‐2‐thione and 1,3‐Imidazoline‐2‐thione

Reactions of copper(I) halides (Cl, Br, I) with 1‐methyl‐1, 3‐imidazoline‐2‐thione (mimzSH) in 1 : 2 molar ratio yielded sulfur‐bridged dinuclear [Cu₂X₂(μ‐S‐mimzSH)₂(η¹‐S‐mimzSH)₂] (X = I, 1 , Br, 2 ; Cl, 3 ) complexes. Copper(I) iodide with 1,3‐imidazoline‐2‐thione (imzSH₂) and Ph₃P in 1 : 1 : 1 molar ratio has also formed a sulfur‐bridged dinuclear [Cu₂I₂(μ‐S‐imzSH₂)₂(PPh₃)₂] ( 4 ) complex. The central Cu(μ‐S)₂Cu cores form parallelograms with unequal Cu–S bond distances {2.324(2), 2.454(3) Å} ( 1 ); {2.3118(6), 2.5098(6) Å} ( 2 ); {2.3075(4), 2.5218(4) Å} ( 3 ); {2.3711(8), 2.4473(8) Å} ( 4 ). The Cu···Cu separations, 2.759–2.877Å in complexes 1 – 3 are much shorter than 3.3446Å in complex 4 . The weak intermolecular interactions {H₂CH···S^# ( 2 ); CH···Cl^# ( 3 ); NH···I^# ( 4 )} between dimeric units in complexes 2 – 4 lead to the formation of linear 1D polymers.     

trans‐Di­chlorotetrakis(4‐methyl­pyridine)­silicon bis­(triiodide) chloro­form solvate

At 173 K, the dication of the title compound, C₂₄H₂₈Cl₂N₄Si²⁺·2I₃^?·CHCl₃, is located on a crystallographic fourfold rotation axis. The chloro ligands occupy axial positions and the four 4‐methyl­pyridine ligands lie in the equatorial plane. The almost linear I₃^? ion is located on a crystallographic mirror plane and displays two significantly different I—I bond lengths. Furthermore, chloro­form mol­ecules, which are disordered about a centre of inversion, fill the remaining gaps in the crystal structure.     

Weak hydrogen and halogen bonding in 4‐[(2,2‐difluoroethoxy)methyl]pyridinium iodide and 4‐[(3‐chloro‐2,2,3,3‐tetrafluoropropoxy)methyl]pyridinium iodide

To enable a comparison between a C—H…X hydrogen bond and a halogen bond, the structures of two fluorous‐substituted pyridinium iodide salts have been determined. 4‐[(2,2‐Difluoroethoxy)methyl]pyridinium iodide, C₈H₁₀F₂NO⁺·I⁻, (1), has a –CH₂OCH₂CF₂H substituent at the para position of the pyridinium ring and 4‐[(3‐chloro‐2,2,3,3‐tetrafluoropropoxy)methyl]pyridinium iodide, C₉H₉ClF₄NO⁺·I⁻, (2), has a –CH₂OCH₂CF₂CF₂Cl substituent at the para position of the pyridinium ring. In salt (1), the iodide anion is involved in one N—H…I and three C—H…I hydrogen bonds, which, together with C—H…F hydrogen bonds, link the cations and anions into a three‐dimensional network. For salt (2), the iodide anion is involved in one N—H…I hydrogen bond, two C—H…I hydrogen bonds and one C—Cl…I halogen bond; additional C—H…F and C—F…F interactions link the cations and anions into a three‐dimensional arrangement.     

Coulometric titration of iodide and iodine with electrolytically generated hypobromite

Conditions for the quantitative coulometric titration of iodide and iodine with electrolytically generated hypobromite in the presence of borax buffer have been established. Iodide and iodine are oxidized to iodate. The method, with biamperometric indication of the equivalence point, was successfully applied for a wide range of iodide concentrations (6.21–2115μg with reliability intervals of ±0.21–±11μg) and iodine concentrations (24.26–3311μg with reliability intervals of ±0.36–±11.7μg). The determinations are accurate and sensitive even in the presence of large amounts of bromides and chlorides ($\text{Br}{}^{\mathrm{?}}\text{I}{}^{\mathrm{?}}$= 1.2·10⁶ and $\text{C}\text{l}$^?I^?=4.0·10^{3), as well as in the presence of oxidizing agents such as IO₃?, BrO₃? and CrO₄2? ($\text{I}\text{O}$₃?/I₂)=3.2·105, $\text{I}\text{O}$₃?/I₂=3.1·103, $\text{Br}\text{O}$-₃/I₂}=1.1·10⁴ and $\text{Cr}\text{O}$^2-₄/I₂=1.0·10⁴, as was confirmed by statistical tests. The oxidation mechanism under the conditions of coulometric titrations is discussed.     

(Z)‐2‐Methylbuten‐1‐yl(aryl)iodonium trifluoromethanesulfonates containing electron‐withdrawing groups on the aryl moiety

The crystal structures of [(Z)‐2‐methyl­but‐1‐en‐1‐yl]­[4‐(tri­fluoro­methyl)­phenyl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₂H₁₃F₃I⁺·CF₃O₃S^?, (I), (3,5‐di­chloro­phenyl)­[(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium tri­fluoro­methane­sulfonate, C₁₁H₁₂­Cl₂I⁺·CF₃O₃S^?, (II), and bis{[3,5‐bis­(tri­fluoro­methyl)­phenyl][(Z)‐2‐methyl­but‐1‐en‐1‐yl]­iodo­nium} bis­(tri­fluoro­methane­sulfonate) di­chloro­methane solvate, 2C₁₃H₁₂F₆I⁺·­2CF₃­O₃S^?·CH₂Cl₂, (III), are described. Neither simple acyclic β,β‐di­alkyl‐substituted alkenyl­(aryl)­idonium salts nor a series containing electron‐deficient aryl rings have been described prior to this work. Compounds (I)–(III) were found to have distorted square‐planar geometries, with each I atom interacting with two tri­fluoro­methane­sulfonate counter‐ions.     

[2,6‐Bis(3,5‐dimethylpyrazol‐1‐ylmethyl)pyridine]iodocopper(I) dichloromethane solvate

The title compound, [CuI(C₁₇H₂₁N₅)]·CH₂Cl₂, contains a tetracoordinate Cu^I centre with an unusual distorted tetrahedral stereochemistry, which has also been observed in other Cu^I complexes containing this tridentate ligand. This distortion is probably a result of intermolecular steric contacts between the I^? ligand and a neighbouring CH₂Cl₂ mol­ecule.     

Formation and Crystal Structure of the Salt (IC(PPh3)2)2I[I3]·(I2)2 with a new Polyiodide Chain

The reaction of the carbodiphosphorane Ph₃P=C=PPh₃ ( 1 ) with MeI in the presence of iodine gives the oxidation product (IC(PPh₃)₂)₂I[I₃]·(I₂)₂ ( 2 ). In the solid state dimeric units linked by indefinite ···I^?···I₂···I₃^?···I₂···I^?··· chains are found. An additional I···I contact between the cation and the I₂ molecule is formed, amounting to 359.23(5) pm. 2 crystallizes in the monoclinic space group P2/c, with the unit cell dimensions a = 2053.9(1), b = 1011.4(1), c = 1889.8(1) pm; β = 105.21(1)° and Z = 4.     

Synthesis and Nonlinear Optical Properties of a New A-π-A Two-Photon Compound Utilizing Dibenzothiophene as Center

A new two‐photon material, 3E,6E‐bis(2‐pyrid‐4′‐ylvinyl)dibenzothiophene (BPVDBT), has been firstly synthesized by an efficient Pd‐catalyzed Heck coupling route. The single‐ and two‐photon fluorescence, quantum yields, lifetimes, solvent effects of the chromophore were studied in detail and the compound exhibited solvent‐sensitivity. The fluorescence intensity (I_out) and input excitation intensity (I_in) can fit in well with the quadratic parabolas, which indicates that the up‐converted fluorescence was induced by the two‐photon absorption (TPA). TPA cross‐section of BPVDBT has been measured using the two‐photon‐induced fluorescence method, whose value is 14.24×10^?50 cm⁴·s·photon^?1·molecule^?1 at 750 nm. The experimental results confirm that BPVDBT is a good two‐photon absorbing chromophore with an A‐π‐A type.     

Untersuchungen an Polyhalogeniden. XVI. Darstellung und Kristallstrukturen der Bipyridiniumpolyiodide Bipy · HIn mit n = 3, 5 und 7

Studies on Polyhalides. 16. Preparation and Crystal Structures of Bipyridiniumpolyiodides Bipy · HI_n with n = 3, 5, and 7 With simply protonated α,α′-Bipyridyl Bipy · H⁺ a triiodide Bipy · HI₃, a pentaiodide Bipy · HI₅ and a heptaiodide Bipy · HI₇ may be prepared in the presence of iodide ions I^? and dependent of the iodine I₂ content. Bipyridiniumtriiodide C₁₀H₉N₂I₃ crystallizes at room temperature monoclinically in P2₁/n with a = 1 122.8(1) pm, b = 1 072.7(1) pm, c = 1 200.2(3) pm, β = 98.02(2)° and Z = 4. The crystal structure is built up from mixed cationic and anionic layers. Bipyridiniumpentaiodide C₁₀H₉N₂I₅ crystallizes at room temperature monoclinically in P2₁/c with a = 887.3(5) pm, b = 2 527.9(12) pm, c = 830.7(3) pm, β = 106.78(5)° and Z = 4. The crystal structure contains triiodide ions I₃^? till now uniquely connected by iodine molecules I₂ in a trigonal planar way. Bipyridiniumheptaiodide C₁₀H₉N₂I₇ crystallizes at room temperature triclinically in P&1macr; with a = 713.1(3) pm, b = 1 007.9(3) pm, c = 1 464,8(4) pm, α = 81.07(3)°, β = 89.92(3)°, γ = 82.77(3)° and Z = 2. The crystal structure contains a V-shaped pentaiodide ion I₅^? completed by an iodine molecule I₂ to a trigonal pyramidally shaped heptaiodide ion I₇^? and at the same time connected to a zigzag chain.     

Triiodide‐Mediated δ‐Amination of Secondary C−H Bonds

The C_δ?H amination of unactivated, secondary C?H bonds to form a broad range of functionalized pyrrolidines has been developed by a triiodide (I₃^?)‐mediated strategy. By in situ 1) oxidation of sodium iodide and 2) sequestration of the transiently generated iodine (I₂) as I₃^?, this approach precludes undesired I₂‐mediated decomposition which can otherwise limit synthetic utility to only weak C(sp³)?H bonds. The mechanism of this triiodide‐mediated cyclization of unbiased, secondary C(sp³)?H bonds, by either thermal or photolytic initiation, is supported by NMR and UV/Vis data, as well as intercepted intermediates.     

Tris(1,9‐diethyl­adeninium) triiodide diiodide

X‐ray analysis of the title compound reveals three crystallographically distinct cations of 1,9‐diethyl­adeninium, two iodide anions and one triiodide anion in the asymmetric unit, giving six residues and the formula 3C₉H₁₄N₅⁺·I₃⁻·2I⁻. Standard purine nomenclature is used to identify the atoms of each adenine moiety. Hydrogen bonding is observed between atoms N6 and N7 of a pair of cations [N⋯N = 2.885 (4)/2.902 (3) and 2.854 (3)/2.854 (3) Å], with additional hydrogen bonding to I⁻ anions via the other N6 H atom [N⋯I = 3.708 (3), 3.738 (3) and 3.638 (3) Å]. The triiodide anion is not involved in hydrogen bonding. The bond lengths and angles of the 1,9‐diethyl­adeninium cations are compared with literature values and confirm the formation of the imine tautomer.     

The chloride,bromide and iodide salts of 1‐(diaminomethylene)thiouron‐1‐ium

Crystals of 1‐(diaminomethylene)thiouron‐1‐ium chloride, C₂H₇N₄S⁺·Cl⁻, 1‐(diaminomethylene)thiouron‐1‐ium bromide, C₂H₇N₄S⁺·Br⁻, and 1‐(diaminomethylene)thiouron‐1‐ium iodide, C₂H₇N₄S⁺·I⁻, are built up from the nonplanar 1‐(diaminomethylene)thiouron‐1‐ium cation and the respective halogenide anion. The conformation of the 1‐(diaminomethylene)thiouron‐1‐ium cation in each case is twisted. Both arms of the cation are planar and rotated in opposite directions around the C—N bonds involving the central N atom. The dihedral angles describing the twisted conformation are 22.9 (1), 15.2 (1) and 4.2 (1)° in the chloride, bromide and iodide salts, respectively. Ionic and extensive hydrogen‐bonding interactions join oppositely charged units into a supramolecular network. The aim of the investigation is to study the influence of the size of the ionic radii of the Cl⁻, Br⁻ and I⁻ ions on the dimensionality of the hydrogen‐bonding network of the 1‐(diaminomethylene)thiouron‐1‐ium cation. The 1‐(diaminomethylene)thiouron‐1‐ium system should be of use in crystal engineering to form multidimensional networks.     

Use of A Novel Acetone-H2O2−C10− Chemiluminescence System for the Determination of Iodide Ion

Abstract

The present paper reports a new chemiluminescence system, i.e, acetone-H₂O₂?C10^?, which can be catalyzed by iodide ion (I^?). Based on this catalysis, a new chemiluminescence method for the determination of trace iodide ion is proposed. the optimum conditions are reported in this note. the detection limit is 2 × 10^?11 g/ml I^?, the linear dynamic range is 4 × 10^?10 g/ml to 3 × 10^?7 g/ml I^?, and the variation coefficient at an iodide concentration of 5 × 10^?9 g/ml I^? (n=10) is 4.6%. the method has been satisfactorily applied to the determination of trace iodide ion in water.     

Bis(methyltri‐o‐tolylphosphonium) octaiodide

In the crystal structure of the title compound, 2C₂₂H₂₄P⁺·I₈²⁻, the I₈²⁻ anion is located on a crystallographic inversion centre and consists of two tri‐iodide anions linked by di‐iodine at angles of 89.92 (4)° to form a planar `Z'‐shaped dianion. The octaiodides are linked via long‐range interactions [3.877 (11) Å] into infinite polyiodide ribbons. This is the first example of a structure containing an [(o‐tolyl)₃PMe]⁺ cation, and the C_Me—P—C—C_Me torsion angles of −54.0 (11), −51.3 (11) and −48.2 (11)° indicate that the configuration is exo₃.