Fluoride anion induced novel reaction of α-(sulfonio)ketone triflate

α-(Phenylmethylsulfonio)ketone triflates (1) are treated with a suspension of KF in aprotic polar solvent to give dimeric 2-acylcyclobutanones (2), which are rearranged to γ,δ-unsaturated δ-valerolactones (3) by acid catalyst.     

Raman spectra of haloselenate(IV) ions—the SeO2Br− anion

Compounds of the bromoselenite ion, MSeO₂Br(M⁺ = φ₄Sb⁺, n-Bu₄N⁺) have been prepared and their Raman spectra studied. The spectra are consistent with C_s symmetry. A normal coordinate analysis of the spectra of SeO₂F⁻, SeO₂Cl⁻ and SeO₂Br⁻ has been done and force constants determined. The SeX bonds are shown to be remarkably weak.     

Tetramidocavitand: strong anion receptor by well-organized four -(CO)N-H?X interactions

Resorcin[4]arene-based tetramidocavitands containing four secondary amide groups on their upper rim showed strong (R = methyl or ethyl) binding properties. The caviplex formation through hydrogen bonds of -(CO)N-H?X⁻ was supported by ¹H NMR and crystal structure analyses. In a mixture of C₂D₂Cl₄/DMSO/D₂O = 5:15:2 at 25 °C, the thermodynamic parameters for caviplex @1, ΔG (kcal mol⁻¹), ΔH (kcal mol⁻¹), and ΔS (cal K⁻¹ mol⁻¹), are −3.7, −8.6, and −16.7, respectively.     

Synthesis and crystal structure of Co(III) dioximates with the complex anion [SbF6]?

The complexes [Co(DioxH)₂L₂][SbF₆] · nH₂O, where DioxH is dimethylglyoxime monoanion (DioxH^?) or 1,2-cyclohexanedione dioxime (NioxH^?), L is aniline (An) or triphenylphosphine (PPh₃), were isolated from the CoX₂ · nH₂O-NaSbF₆-DioxH₂-L system (X = F or CH₃COO) in aqueous methanol. The complexes were studied by UV, IR, and NMR spectroscopy and by X-ray diffraction. The crystal structure of [Co(DH)₂(An)₂][SbF₆] · H₂O (I) and [Co(NioxH)₂(PPh₃)₂][SbF₆] (II) is stabilized by the electrostatic interactions between the Co(III) complex cations and outer-sphere fluorine-containing anions and by hydrogen bonds between structural units.     

Sorption of nicotinic and isonicotinic acids by the strongly basic anion exchanger АВ-17-8

Thermodynamics and kinetics of sorption with the participation of nicotinic and isonicotinic acids on the strongly basic anion exchanger АВ-17-8 were studied. According to calorimetric measurements, partial (differential) heat of sorption was estimated for anions and zwitterions of pyridinecarboxylic acids upon sorption by the OH-form of the anion exchanger AB-17-8 at 298K. Sorption of zwitterions of pyridinecarboxylic acids by the OH-form of the strongly basic anion exchanger can be presented as the process that involves independent reactions of ion exchange, dissociation of pyridinecarboxylic acid, and neutralization. The kinetics of sorption on the strongly basic anion exchanger with the participation of nicotinic and isonicotinic acids is shown to be controlled by the slow diffusion of the components in the polymer phase. For the organic anion in the phase of the anion exchanger АВ-17-8, the diffusion coefficient is equal to (1.3±0.4)?10^–12 m² s^–1.     

De-protonation of (η4-isoprene)Fe(CO)3; an isoprene anion equivalent

(η⁴-Isoprene)Fe(CO)₃ can be deprotonated with lithium diisopropylamide. The resulting coordinated isoprene anion reacts with electrophiles at low temperature, but rearranges to an isomeric (η⁴-trimethylenemethane)Fe(CO)₃ anion derivative at higher temperatures.     

Influence of the outer-sphere cation nature on the crystal structures of salts with a cis-[Rh(NH3)2(NO2)4]− anion

Complex rhodium(III) salts of the composition cis-M[Rh(NH₃)₂(NO₂)₄]·nH₂O, where M = K⁺, Cs⁺, Ag⁺, (CH₃)₄N⁺, are synthesized and described. Their molecular and crystal structures are determined by single crystal X-ray diffraction.     

Are the anions MeO(CO) (n = 1 and 2) methoxide anion donors in the gas phase? A theoretical investigation

• 1. The anions CH₃O‐^–CO and CH₃OCO‐^–CO are both methoxide anion donors. The processes CH₃O‐^–CO → CH₃O^– + CO and CH₃OCO—CO → CH₃O^– + 2CO have ΔG values of +8 and ?68 kJ mol^?1, respectively, at the CCSD(T)/6‐311++G(2d, 2p)//B3LYP/6‐311++G(2d,2p) level of theory.
• 2. The reactions CH₃OCOCO → CH₃OCO + CO (ΔG = ?22 kJ mol^?1) and CH₃COCH(O^–)CO₂CH₃ → CH₃COCH(O^–)OCH₃ + CO (ΔG = +19 kJ mol^?1) proceed directly from the precursor anions via the transition states (CH₃OCO…CO₂)^– and (CH₃COCHO…CH₃OCO)^–, respectively.
• 3. Anion CH₃COCH(O^–)CO₂CH₃ undergoes methoxide anion transfer and loss of two molecules of CO in the reaction sequence CH₃COCH(O^–)CO₂CH₃ → CH₃CH(O^–)COCO₂CH₃ → [CH₃CHO (CH₃OCO‐^–CO)] → CH₃CH(O^–)OCH₃ + 2CO (ΔG = +9 kJ mol^?1). The hydride ion transfer in the first step is a key feature of the reaction sequence.

Copyright © 2010 John Wiley & Sons, Ltd.     

Trinuclear Cu(II) and Zn(II) complexes bridged by μ3-carbonato anion

The trinuclear Cu(II) and Zn(II) complexes [(CuTPA),(μ₃-CO,)] (C10₄)₄(1) and [(ZnTPA),(μ₃-C0₃)](C10₄)₄ (2) (TPA = tri(pyridylmethy1)amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO₃ ^2- anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO₃ ²- comes from atmospheric CO₂. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular hipyramidal environment. The [(CuTPA)₃(μ₃-C0₃) ](C10₄), compound shows a very weak antifemmagnetic coupling. Project supported by the National Natural Science Foundation of China (Grant No.29771021).     

Trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes bridged by μ_3-carbonato anion

The trinuclear Cu(Ⅱ) and Zn(Ⅱ) complexes [(CuTPA)_3(μ3-CO_3)] (ClO_4)_4(1) and [(ZnTPA)_3(μ_3-CO_3)] (ClO_4)_4 (2) (TPA=tri(pyridylmethyl) amine) have been synthesized. X-ray structure analysis of the two complexes proves that CO_3~(2-) anion has an unusual triply bridging ligand, bridging three CuTPA and ZnTPA units respectively, and assembles new trinuclear complexes. The CO_3_(2-) comes from atmospheric CO_2. The structure of each trinuclear unit consists of three copper or zinc atoms in a five-coordinate triangular bipyramidal environment. The [(CuTPA)_3 (μ_3-CO_3)] (ClO_4)_4 compound shows a very weak antiferromagnetic coupling.     

Crystal structure of two complexes containing tris-(β-diketonato)magnate anion

Single crystal XRD is used to determine the structures of the complexes (H₂TMEDA)[Mg(ptac)₃]₂ (1, TMEDA = Me₂N(CH₂)₂NMe₂, ptac = ^t BuCOCHCOCF₃) and (H₂TMEDA)[Mg(hfac)₃](hfac) (2, hfac = CF₃COCHCOCF₃) at a temperature of 150 K. The crystallographic data for complex 1: a = 10.2919(3) Å, b = 10.9492(4) Å, c = 15.4159(6) Å, α = 87.117(1)°, β = 89.686(1)°, γ = 79,864(1)°, space group $P\bar 1$ Z = 1, R = 0.0573; for complex 2: a = 12.9446(2) Å, b = 23.0035(4) Å, c = 13.1473(3) Å, β = 98.779(1)°, space group P2₁/n, Z = 4, R = 0.0605. The structures are ionic; the metal atom coordinates six oxygen atoms of three β-diketonate ligands. The distances Mg-O in complex 1 are in the range 2.036(2)–2.0920(19) Å; the same distances in complex 2 are in the range 2.051(2)–2.076(2) Å. The spatial packing is determined by the system of hydrogen bonds between the (H₂TMEDA)²⁺ cations and [Mg(ptac)₃]^? (1) or hfac^? (2) anions. A thermogravimetric study of complex 1 is carried out.     

(S)-(-)-norlaudanosine和(S)-(-)-O,O-dimethylcoclaurine的合成

以高藜芦胺为起始原料,经N-磺酰化反应制得高藜芦磺酰胺(2);2分别与芳乙烯甲醚经对甲苯磺酸催化的Pictet-Spengler反应后用金属钠脱除Ts基团合成了(±)-norlaudanosine(5a)和(±)-O,O-dimethylcoclaurine(5b);使用半量拆分法,以N-乙酰-L-苯丙氨酸为拆分剂,制得(S)-(-)-5a和(S)-(-)-5b,其结构经1H NMR,13C NMR,IR,MS和HR-ESI-MS确证。     

Synthesis and structure of new thiourea-containing Cobalt(III) dioximates with the [TiF6]2− anion

The new Co(III) dioximates [Co(DH₂)(D)(Thio)₂]₂[TiF₆] ·2DMF (I), [Co(NioxH)₂(Thio)₂]₂[TiF₆] · 2.25H₂O (II), and [Co(DpgH)₂(Thio)₂]₂[TiF₆] · 4DMF · 1.5H₂O (III) have been synthesized and studied (DH₂ and D are, respectively, the dimethylglyoxime molecule and doubly charged anion; NioxH and DpgH are singly charged anions of 1,2-cyclohexanedione dioxime and diphenylglyoxime, respectively; Thio is thiourea; DMF is dimethylformamide). The composition and structure of the complexes have been studies by IR, UV, and NMR spectroscopy. The crystal structures have been determined by X-ray crystallography. The hydrogen bonds in the structures are formed by fluorine atoms of the [TiF₆]^2? anion with Co(III) complex cations and solvent molecules of crystallization. The amino groups of coordinated thiourea molecules are also involved in the hydrogen bond system, which is responsible for their different arrangement with respect to the equatorial planes of the Co(III) complex cations.     

Reduction of sterically hindered β-diketiminato europium(III) complexes by the β-diketiminato anion: a convenient route for the synthesis of β-diketiminato europium(II) complexes

The metathesis reaction of anhydrous EuCl(3) with sodium salt of bulky β-diketiminato NaL (L = [N(2, 4, 6- Me(3)C(6)H(2))C(Me)](2)CH(-), L(2, 4, 6-Me3); [N(2,6-(i)Pr(2)C(6)H(3))C(Me)](2)CH(-), L(2, 6-ipr2) and [(2, 6-(i)Pr(2)C(6)H(3))NC(Me)CHC(Me)N(C(6)H(5))](-), L(2, 6-ipr2)(Ph)) in THF at 60 °C afforded the corresponding Eu(II) complexes: Eu(II)(L(2, 4, 6-Me3))(2)(THF) (1), Eu(II)(L(2, 6-ipr2))(2) (2) and Eu(II)(L(2, 6-ipr2)(Ph))(2) (5) with the formations of dimers (L(2, 4, 6-Me3))(2) (3) and (L(2, 6-ipr2))(2) (4) for the former two reactions and proligand L(2, 6-ipr2)(Ph)H (6) for the latter one. Compounds 1-6 were confirmed by an X-ray crystal structure analysis. The central metal Eu(II) in 1 is coordinated by two monoanionic L(2, 4, 6-Me3) ligands and one THF molecule in a trigonal bipyramid. The Eu(II) in each of 2 and 5 is ligated by two monoanionic ligands to form a tetrahedral geometry. The BVS (Bond Valence Sum) calculation indicates the oxidation state of Eu in all the three complexes is 2+ (2.12 for 1, 1.86 for 2 and 1.99 for 5). The isolation of dimers of (L(2, 4, 6-Me3))(2) and L(2, 6-ipr2))(2) and proligand L(2, 6-ipr2)(Ph)H demonstrates that the reducing agent in the present reduction of a Eu(III) ion to a Eu(II) ion might be the (L(2, 4, 6-Me3))(-), (L(2, 6-ipr2))(-) and (L(2, 6-ipr2)(Ph))(-), respectively. The possible mechanism for the reduction pathway is presented.     

Tetramethylammonium hexanitratoneodymiate(III). Structural variations of the [Nd(NO3)6]3− anion in a single crystal

The structure of tetramethylammonium hexanitratoneodymiate(III) has been determined at 123?K in the suprisingly low symmetry space group P 1 considering the simplicity of the compound. The structure has Z′?=?4 with seventeen distinct chemical fragments in the asymmetric unit (12 tetramethylammonium cations, three complete [Nd(NO₃)₆]^3? anions and two half [Nd(NO₃)₆]^3? species situated on special positions). This one structure contains five different coordination geometries of the [Nd(NO₃)₆]^3? species.