(Mn1−xPbx)Pb10+ySb12−yS26−yCl4+yO, a new oxy-chloro-sulfide with ∼2 nm-spaced (Mn,Pb)Cl4 single chains within a waffle-type crystal structure

The new oxy-chloro-sulfide (Mn_1−xPb_x)Pb_10+ySb_12−yS_26−yCl_4+yO (x ∈ [0.2-0.3]; y ∈ [0.3-1.6]) was synthesized by dry way at 500-600 °C. A single crystal ∼Mn_0.7Pb_11.0Sb_11.3S_25.3Cl_4.7O indicates a monoclinic symmetry, space group C2/m, with a = 37.480(8), b = 4.1178(8), c = 18.167(4) Å, β = 106.37(3)°, V = 2690.2(9) Å³, Z = 2. Its crystal structure was determined by X-ray single crystal diffraction, with a final R = 5.11%. Modular analysis of the crystal structure reveals a “waffle” architecture, where complex rods with lozenge section delimitate an internal channel filled by a single chain of (Mn_0.7Pb_0.3)Cl₆ octahedra connected by opposite edges. Minimal inter-chain distances are close to 18 Å. The rod wall, two-atom thick, presents, in alternation with S atoms, Pb or (Pb,Sb) cations with prismatic coordination in the internal atom layer, while the external atom layer is constituted exclusively by Sb cations with dissymmetric square pyramidal coordination. A (Pb,Sb)₂S₂ fragment connects two successive rods along (2 0 1) to form a waffle-type palissadic layer. The unique O position, half filled, presents the same environment than the isolated O positions in the oxy-sulfide Pb₁₄Sb₃₀S₅₄O₅, or oxy-chloro-sulfides Pb₁₈Sb₂₀S₄₆Cl₂O and (Cu,Ag)₂Pb₂₁Sb₂₃S₅₅ClO. This compound belongs to a pseudo-homologous series of chalcogenides with waffle structure, ordered according to the size of their lozenge shape channel. Such a complex senary compound of the oxy-chloro-sulfide type illustrates the structural competition between three cations, on one hand, and, on the other hand, three anions. This compound is of special interest regarding the 1D distribution of magnetic Mn²⁺ atoms at the ∼2 nm scale.     

Ethylene polymerization by novel Ziegler–Natta‐type catalysts obtained in situ by the oxidative addition of 8‐hydroxyquinoline‐based ligands to bis(1,5‐cyclooctadiene)nickel(0) and methylaluminoxane

Novel catalytic systems, prepared in situ by the oxidative addition of 8‐hydroxyquinoline ligands to bis(1,5‐cyclooctadiene)nickel(0) and activated by methylaluminoxane, were studied in ethylene polymerization. When 8‐hydroxyquinoline was employed, only oligomeric products were obtained. On the contrary, 5,7‐dinitro‐8‐hydroxyquinoline gave linear polyethylene (PE), but with a modest activity. For the catalyst based on 5‐nitro‐8‐hydroxyquinoline, the productivity was largely dependent on the content of free trimethylaluminum (TMA) present in the commercial aluminoxane. The progressive optimization of the TMA/oligomeric methylaluminoxane ratio increased the productivity, which reached 700 kg of PE/(mol of Ni × h), by an order of magnitude. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 200–206, 2006     

Synthesen von Heterocyclen, 122. Mitt.: Über die Reaktion des Perimidons mit aktiven Malonestern

Zusammenfassung Perimidon (1) reagiert mit monosubstit. Malonsäure-trichlorphenylestern (2) bei 250° zu 9-Hydroxy-5,7-dioxo-4,5-dihydro-7H-pyrido[1,2,3-cd]perimidinen (3), die durch saure Hydrolyse zu 10-Amino-4-hydroxy-benzo[h]carbostyrilen (4) gespalten werden.

---

Syntheses of heterocycles, CXXII: Reaction of perimidone with reactive malonates

Perimidone (1) reacts with monosubstituted 2.4.6-trichlorophenyl malonates at 250° to 9-hydroxy-5.7-dioxo-4.5-dihydro-7H-pyrido[1.2.3-cd]perimidines (3), which are cleaved by acid yielding 10-amino-4-hydroxy-benzo[h]quinolin-2-ones (4).

     

Microwave-assisted arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids

The palladium-catalyzed arylation of rac-(E)-3-acetoxy-1,3-diphenylprop-1-ene with arylboronic acids was studied under controlled microwave irradiation conditions. A variety of different catalysts, bases, and solvents were explored in order to achieve optimum yields in the shortest possible reaction times. The best isolated yields were obtained using Pd₂(dba)₃·CHCl₃/PPh₃ as the catalytic system, potassium phosphate monohydrate as the base, and toluene/H₂O as a solvent system. Microwave irradiation using 5 mol % of the palladium catalyst for 90 s (max. temp 170 °C) generally afforded the cross-coupling products in good to excellent yields.     

Lower bounds for faithful,preinjective modules

Let be the path algebra for some representation-infinite quiver over some field k. There exists a bound such that ^mI is faithful for all indecomposable injective -modules I and all , and such that there exists an indecomposable injective -module J satisfying that J is not faithful, denotes the Auslander-Reiten-translation. Let m() be the maximum of the taken over all possible orientations of the underlying graph . In this article we determine the bounds m() for representation-infinite quivers for which is a tree.     

High-speed microwave-promoted hetero-Diels-Alder reactions of 2(1H)-pyrazinones in ionic liquid doped solvents

Inter- and intramolecular hetero-Diels-Alder reactions in a series of functionalized 2(1H)-pyrazinones were investigated under controlled microwave irradiation. The cycloaddition reactions were efficiently performed in sealed tubes, utilizing either a combination of 1,2-dichloroethane and a thermally stable ionic liquid, or 1,2-dichlorobenzene as reaction medium. In all cases, a significant rate-enhancement using microwave flash heating as compared to thermal heating was observed.     

Alkylierung ambidenter Heterocyclen-Anionen, 1. Mitt.: Über die Benzylierung des 4-Hydroxy-carbostyrils

Zusammenfassung 4-Hydroxy-carbostyrile (1a–c) werden mit Benzylchlorid inDMF bevorzugt zu den 4-Benzyloxy-carbostyrilen (2a–c) alkyliert. In wäßr. NaOH dagegen erhält man aus1a und1c als Hauptprodukt das 3,3-Dibenzyl-2,4-dioxo-1,2,3,4-tetrahydrochinolin (3).

---

Alkylation of 4-hydroxy-quinol-2-ones (1a–c) with benzyl chloride inDMF in the presence of K₂CO₃ mainly gives the 4-benzylethers2a–c. However, carbon dialkylation takes place in aqueous NaOH and the main product of the reaction between benzylchloride and1a is 3.3-dibenzyl-2.4-dioxo-1.2.3.4-tetrahydro-quinoline3.

     

Synthesen von Heterocyclen, 130. Mitt.: Über das Glomerin und das Arborin

Zusammenfassung Es werden einstufige Synthesen desGlomerins (2) [1,2-Dimethyl-4(1H)-chinazolinon] und desArborins (3) [1-Methyl-2-benzyl-4(1H)-chinazolinon] bekanntgegeben.

---

Syntheses of heterocycles, CXXX: Glomerine and arborine

A one step synthesis ofglomerine (2) [1.2-dimethyl-4(1H)-quinazolinone] andarborine (3) [1-methyl-2-benzyl-4(1H)-quinazolinone] is described.

     

A correlation study of Li ground state by the MCHF procedure

Results are reported for multiconfiguration Hartree–Fock studies of correlation in the lithium ground state, which maintain orthogonality of orbitals within a configuration. It is shown that when the 1s- and 2s-orbitals are fixed at their Hartree–Fock value, configurations for which Brillouin's theorem holds may be important, particularly for atomic properties other than energy. The Fermi contact term is considered as an example.     

Untersuchungen zur Temperaturabhängigkeit charakteristischer IR-Absorptionen, 9. Mitt.: Zur Tautomerie des “o-Hydroxymandelsäurelactons”

Zusammenfassung Die Abhängigkeit der Struktur des o-Hydroxymandelsäurelactons von Lösungsmittel und Temperatur wird mit Hilfe IR- und NMR-spektroskopischer Methoden nachgewiesen.

---

The temperature and solvent dependence of the structures of 2-hydroxymandelic acid lactone and dioxindole have been shown by IR and NMR spectroscopy.