ChemInform Abstract: At the Border of Intermetallic Compounds and Transition‐Metal Oxides: Crystal Intergrowth of the Zintl Phase Cs4Ge9 and Cs2WO4 or Cs3VO4 as well as Nine‐Atom Cluster Relocation in the Solid State.

Compounds (III) and (VI) containing [Ge₉]^4‐ clusters and oxometallate anions WO₄^2‐ or VO₄^3‐ are characterized by single crystal XRD and Raman spectroscopy.     

Darstellung und Kristallstruktur der bekannten Zintl‐Phasen Cs3Sb7 und Cs4Sb2

Synthesis and Crystal Structure of the known Zintl Phases Cs₃Sb₇ and Cs₄Sb₂ Cs₃Sb₇ and Cs₄Sb₂ were synthesized from the elements and their crystal structures were determined on the basis of single crystal x‐ray data. Cs₃Sb₇ crystallizes in the monoclinic system with space group P2₁/c (a = 1605.7(1) pm, b = 1571.1(1) pm, c = 2793.9(2) pm, β = 96.300(2)°, Z = 16) and contains anions Sb₇^3–. In the structure of Cs₄Sb₂ (orthorhombic, space group Pnma, a = 1598.5(3) pm, b = 631.9(2) pm, c = 1099.5(2) pm, Z = 4) dumbbells Sb₂^4– are present.     

Synthese und Kristallstruktur des Fluorid‐ino‐Oxosilicats Cs2YFSi4O10

Synthesis and Crystal Structure of the Fluoride ino‐Oxosilicate Cs₂YFSi₄O₁₀ The novel fluoride oxosilicate Cs₂YFSi₄O₁₀ could be synthesized by the reaction of Y₂O₃, YF₃ and SiO₂ in the stoichiometric ratio 2 : 5 : 3 with an excess of CsF as fluxing agent in gastight sealed platinum ampoules within seventeen days at 700 °C. Single crystals of Cs₂YFSi₄O₁₀ appear as colourless, transparent and water‐resistant needles. The characteristic building unit of Cs₂YFSi₄O₁₀ (orthorhombic, Pnma (no. 62), a = 2239.75(9), b = 884.52(4), c = 1198.61(5) pm; Z = 8) comprises infinite tubular chains of vertex‐condensed [SiO₄]^4? tetrahedra along [010] consisting of eight‐membered half‐open cube shaped silicate cages. The four crystallographically different Si⁴⁺ cations all reside in general sites 8d with Si–O distances from 157 to 165 pm. Because of the rigid structure of this oxosilicate chain the bridging Si–O–Si angles vary extremely between 128 and 167°. The crystallographically unique Y³⁺ cation (in general site 8d as well) is surrounded by four O^2? and two F^? anions (d(Y–O) = 221–225 pm, d(Y–F) = 222 pm). These slightly distorted trans‐[YO₄F₂]^7? octahedra are linked via both apical F^? anions by vertex‐sharing to infinite chains along [010] (?(Y–F–Y) = 169°, ?(F–Y–F) = 177°). Each of these chains connects via terminal O^2? anions to three neighbouring oxosilicate chains to build up a corner‐shared, three‐dimensional framework. The resulting hexagonal and octagonal channels along [010] are occupied by the four crystallographically different Cs⁺ cations being ten‐, twelve‐, thirteen‐ and fourteenfold coordinated by O^2? and F^? anions (viz.[(Cs1)O₁₀]^19?, [(Cs2)O₁₀F₂]^21?, [(Cs3)O₁₂F]^24?, and [(Cs4)O₁₂F₂]^25? with d(Cs–O) = 309–390 pm and d(Cs–F) = 360–371 pm, respectively).     

A Novel Vanadosilicate with Hexadeca‐Coordinated Cs+ Ions as a Highly Effective Cs+ Remover

The effective removal of ¹³⁷Cs⁺ ions from contaminated groundwater and seawater and from radioactive nuclear waste solutions is crucial for public health and for the continuous operation of nuclear power plants. Various ¹³⁷Cs⁺ removers have been developed, but more effective ¹³⁷Cs⁺ removers are still needed. A novel microporous vanadosilicate with mixed‐valence vanadium (V⁴⁺ and V⁵⁺) ions is now reported, which shows an excellent ability for Cs⁺ capture and immobilization from groundwater, seawater, and nuclear waste solutions. This material is superior to other known materials in terms of selectivity, capacity, and kinetics, and at very low Cs⁺ concentrations, it was found to be the most effective material for the removal of radioactive Cs⁺ ions under the test conditions. This novel vanadosilicate also contains hexadeca‐coordinated Cs⁺ ions, which corresponds to the highest coordination number ever described.     

Cs4K2CuSi2O8: Synthese,Kristallstruktur, UV‐Vis‐IR‐Daten

Cs₄K₂CuSi₂O₈: Synthesis, Crystal Structure, UV‐Vis‐IR Data Cs₄K₂CuSi₂O₈ may be obtained via a redox reaction of KCuO₂ in the presence of Cs₂O and SiO₂ with the container material (Cu) at 450 °C as blue single crystals which are sensitive to moisture. Powder samples were obtained by annealing intimate mixtures of the binary oxides under an inert gas atmosphere (Ar) in sealed Ag containers at 500 °C. The crystal structure contains isolated trimeric anions of [O₂SiO₂CuO₂SiO₂]^6–. Cu²⁺ in square‐planar coordination share trans‐edges with [SiO₄] tetrahedra. Spectroscopic investigations focus on the bonding situation of the [CuO₄] unit (AOM) and characteristic vibrational modes of the silicate.     

Solvothermal Synthesis of Cs0.33WO3/LDHs Composite as a Novel Visible‐Light‐Driven Photocatalyst

A novel Cs_0.33WO₃/LDHs (CWLDH) composite was synthesized by simple two steps solvothermal method and first investigated as the photocatalyst for tetracycline (TC) and Congo red (CR) degradation under visible light irradiation. The CWLDH heterostructures catalysts were characterized by XRD, UV–Vis, SEM, XPS and BET. The composite CWLDH showed enhanced photocatalytic activity compared with pure Cs_0.33WO ₃ and NiAl‐LDH under identical experimental conditions. The enhanced photocatalytic activity was mainly attributed to the higher visible light‐absorbing ability, efficient electron–hole separation and prolonged lifetimes of photogenerated charges. The photocatalyst presented a high photocatalytic activity (92%) at the optimum of CWLDH ‐3 and initial TC concentration of 40 mg L⁻¹. Besides, the degradation efficiency of TC is higher than 75% for reused CWLDH after four cycles, demonstrating that it could be used as a potential catalyst with good photocatalytic activity, stability and reusability. According to the experimental results, a possible photocatalytic mechanism of CWLDH was discussed.     

Heterocyclic compounds from 4h‐3,1‐benzoxazin‐4‐one derivatives as anticancer agent

Behaviour of 2‐(4‐oxo‐4H‐benzo[d][l,3]oxazin‐2‐yl)‐benzoic acid (1) towards nitrogen nucleophiles namely, hydrazine hydrate, in different solvents, ammonium acetate, and o‐phenylenediamine has been investigated to give aminoquinazolin‐4‐one, benzotriazepinone, spiro‐type compound, and nitrogen bridgehead compounds 3‐5 , respectively. Also, reactivity of the aminoquinazolin‐4‐one 2 towards carbon elec‐trophiles such as ethyl acetoacetate, ethyl phenylacetate, ethyl chloroacetate, and aromatic aldehydes has been discussed. Reaction of Schiff s base 8 with sulfur nucleophiles namely o‐aminothiophenol and/or thio‐glycolic acid afforded Michael type adducts. Structural assignments, of products 1‐24 have been confirmed by elemental analysis and spectral data (¹H‐ and ¹³C ‐NMR and MS fragmentation). The bioassay indicates that some of the target compounds obtained have good selective anticancer activity.     

Decarboxylation in the synthesis of 4‐alkyl‐, 4‐alkenyl‐ and 4‐acylpyrimidines

Decarboxylation of allylic esters of 4‐carboxypyrimidines in toluene at 111 °C in the presence of a Pd(0) catalyst, gives a mixture of a 4‐alkenylpyrimidine and a pyrimidine unsubstituted in the 4‐position. If the decarboxylation is carried out in the presence of benzaldehyde, then benzaldehyde is added to the 4‐position. Decarboxylation of 4‐carboxypyrimidines in the presence of different electrophiles, results in incorporation of the electrophile into the 4‐position together with a pyrimidine unsubstituted in the 4‐position. Use of microwave irradiation enhances the rate of the decarboxylations.     

Cs3LiZn2(WO4)4 and Rb3Li2Ga(MoO4)4: different filled derivatives of the cation‐deficient Cs6Zn5(MoO4)8 structure

Two new compounds, namely cubic tricaesium lithium dizinc tetrakis(tetraoxotungstate), Cs₃LiZn₂(WO₄)₄, and tetragonal trirubidium dilithium gallium tetrakis(tetraoxomolybdate), Rb₃Li₂Ga(MoO₄)₄, belong to the structural family of Cs₆Zn₅(MoO₄)₈ (space group I 3d , Z = 4), with a partially incomplete (Zn_5/6□_1/6) position. In Cs₃LiZn₂(WO₄)₄, this position is fully statistically occupied by (Zn_2/3Li_1/3), and in Rb₃Li₂Ga(MoO₄)₄, the 2Li + Ga atoms are completely ordered in two distinct sites of the space group I 2d (Z = 4). In the same way, the crystallographically equivalent A ⁺ cations (A = Cs, Rb) in Cs₆Zn₅(MoO₄)₈, Cs₃LiZn₂(WO₄)₄ and isostructural A ₃LiZn₂(MoO₄)₄ and Cs₃LiCo₂(MoO₄)₄ are divided into two sites in Rb₃Li₂Ga(MoO₄)₄, as in other isostructural A ₃Li₂R (MoO₄)₄ compounds (AR = TlAl, RbAl, CsAl, CsGa, CsFe). In the title structures, the WO₄ and (Zn,Li)O₄ or LiO₄, GaO₄ and MoO₄ tetrahedra share corners to form open three‐dimensional frameworks with the caesium or rubidium ions occupying cuboctahedral cavities. The tetrahedral frameworks are related to that of mayenite 12CaO·7Al₂O₃ and isotypic compounds. Comparison of isostructural Cs₃M Zn₂(MoO₄)₄ (M = Li, Na, Ag) and Cs₆Zn₅(MoO₄)₈ shows a decrease of the cubic lattice parameter and an increase in thermal stability with the filling of the vacancies by Li⁺ in the Zn position of the Cs₆Zn₅(MoO₄)₈ structure, while filling of the cation vacancies by larger Na⁺ or Ag⁺ ions plays a destabilizing role. The series A ₃Li₂R (MoO₄)₄ shows second harmonic generation effects compatible with that of β′‐Gd₂(MoO₄)₃ and may be considered as nonlinear optical materials with a modest nonlinearity.     

Cs2BeCl4 und Cs2 YbCl4: Endglieder der homologen Reihe Cs2MCl4

Cs₂BeCl₄ and Cs₂YbCl₄: End Members of the Homologous Series Cs₂MCl₄ Cs₂BeCl₄ belongs to the β-K₂SO₄ type structure (orthorhombic, Pnma, Z = 4, a = 964.2(4), b = 717.8(3), c = 1246.8(5) pm) and Cs₂YbCl₄ to the K₂NiF₄ type (tetragonal, I4/mmm, Z = 2, a = 541.8(2), c = 1727.6(10) pm). They are with the exception of Cs₂TmCl₄ the end members of minimum and maximum molar volume of the homologous series Cs₂MCl₄. The application of the “theorem of optimal (preferred) volumes” suggests that the other members of the series also can only belong to one of these two structure types (β-K₂SO₄ and K₂NiF₄ type, respectively).     

N‐Methylpyrrolidone Hydroperoxide/Cs2CO3 as an Excellent Reagent System for the Hydroxy‐Directed Diastereoselective Epoxidation of Electron‐Deficient Olefins

This report introduces N‐methylpyrrolidone hydroperoxide (NMPOOH)/base as an excellent reagent system for hydroxy‐directed syn selective epoxidation of electron‐deficient olefins, characterized by high diastereoselectivity, short reaction times and remarkable chemoselectivity, especially in presence of oxidatively labile nitrogen or sulfur atoms. NMPOOH also proves efficient in the oxidation of electron‐deficient aromatic aldehydes, in the removal of oxazolidinone chiral auxiliary, and in the functionalization of alkenes and alkynes, showing wide application potential.     

Cs5Sb8 und β‐CsSb: Zwei neue binäre Zintl‐Phasen

Cs₅Sb₈ and β‐CsSb: Two New Binary Zintl Phases The anion in the crystal structure of the new Zintl phase Cs₅Sb₈ synthesized from the elements (monoclinic, space group P2₁/c, a = 724.4(2) pm, b = 1135.2(3) pm, c = 2750.9(8) pm, β = 96.663(5)°, Z = 4) consists of two and three bonded Sb atoms, which are connected to form puckered nets with 5 and 28 membered rings. β‐CsSb (monoclinic, space group P2₁/c, a = 1519.4(3) pm, b = 734.0(2) pm, c = 1432.2(2) pm, β = 113.661(3)°, Z = 4) crystallizes with a superstructure of the LiAs structure type. As in the α phase (NaP type), twobonded Sb^‐ atoms form neary ideal 4₁ screx chains. In contrast to the α phase the helices have opposite chirality.     

4‐Amino‐TEMPO as N‐Nucleophile in Palladium‐Catalyzed Aminocarbonylation

Palladium‐catalyzed aminocarbonylation of iodobenzene and iodoalkenes (1‐iodocyclohexene, 4‐tert‐butyl‐1‐iodocyclohexene, α‐iodostyrene, 17‐iodoandrost‐16‐ene) was carried out using a free radical (4‐amino‐TEMPO) for the first time. Its reduced form (4‐amino‐2,2,6,6‐tetramethylpiperidine) was also used as N‐nucleophile. The free radical was partially reduced under aminocarbonylation conditions; however, the isolation of carbonylated products bearing a stable radical moiety was successfully accomplished. It was proved that the reduction of the 1‐oxyl functionality took place to higher extent when more severe conditions (40 bar CO pressure) were used. The mixture of carboxamide and 2‐ketocarboxamide products was obtained using iodobenzene because of single and double carbon monoxide insertion, respectively. In turn, carboxamide derivatives were formed exclusively when iodoalkenes were used as substrates.     

First Experimental and Theoretical Kinetic Study of the Reaction of 4‐Hydroxy‐4‐methyl 2‐pentanone as a Function of Temperature

In this work, experimental and theoretical rate coefficients were determined for the first time for the gas‐phase reaction of 4‐hydroxy‐4‐methyl‐2‐pentanone (4H4M2P) with OH radicals as a function of temperature. Experimental studies were carried out over the pressure range of 5–80 Torr and the temperature range of 280–365 K, by using a cryogenically cooled cell coupled to the pulsed laser photolysis‐laser induced fluorescence (PLP–LIF) technique. A detailed oxidation mechanism of 4H4M2P with OH radicals was discussed theoretically under three hydrogen abstraction pathways by using density functional theory calculations and wave function based MP2 method. Single‐point energy calculations were performed at CCSD(T) level of theory with 6–311++G(d,p) basis set. The H‐atom abstraction from the ‐CH₂ group was found to be the dominant channel. The reaction force analysis predicts that the abstraction process is mainly dominated by structural rearrangement. Linear kinetic behavior for all the pathways was found in the range of 278–365 K. An atmospheric lifetime less than 3 days was evaluated for 4H4M2P with respect to its reaction with OH, indicating that the reaction with OH of 4H4M2P may be competitive with losses via photolysis.     

Utility of Benzoxazin‐4‐one and 3‐Aminoquinazolin‐4‐one Derivatives as Precursors for Construction of Potent Insecticidal Heterocycles

In demanding to develop new insecticidal agents, both of 2‐pentylbenzoxazin‐4‐one 1 and 3‐amino‐2‐pentylquinazolin‐4‐one 6 derivatives were subjected to react with different nucleophilic agents, for example, ammonia, o‐phenylenediamine, hydrazine hydrate, and hydroxylamine hydrochloride, and sulfur nucleophile, for example, phosphorous pentasulfide, to construct different heterocyclic systems. The structural elucidations of the synthesized compounds were ascertained from the elemental analyses and the spectral data. Assessment of the biological potency for some of the synthesized compounds as insecticidal agents was evaluated against two different insects named Mythimna separata and Nilaparvata lugens.