Solid state synthesis and characterization of iron（Ⅱ） pyrophosphate Fe2P2O7

Offwhite pure Fe_2P_2O_7 was synthesized through solid phase reaction using Fe_2O_3 and NH_4H_2PO_4 in argon atmosphere.The reaction products of Fe_2O_3 and NH4_H_2PO_4 at a series of temperatures from 400 to 900℃were characterized by XRD.Comparison and analysis of XRD patterns of resultant products indicated well-crystallized Fe_2P_2O_7 could be obtained over 630℃and Fe_2P_2O_7 prepared at 700℃was triclinic in cell type.Comparison of the cell parameters proved that the as-prepared Fe_2P_2O_7 belonged toβ- Fe_2P_2O_7 in crystal phase and SEM showed its size distribution was 0.5-2μm.     

Synthesis,structure and spin-crossover transition of The Cluster Compound Nb6I11−xBrx (0 ⩽ x ⩽ 2.7)

The homogeneous phase Nb₆I_11?xBr_x (0 ? x ? 2.7) is synthesized from Nb₃Br₈, Nb₃I₈ and Nb in sealed Nb capsules at 1 130 K. A second-order phase transition is found as for the composition Nb₆I₁₁ itself, changing the space group from P2₁cn (low temperatures) to Pccn, accompanied by a spin-crossover from a doublet to a quartet state. With increasing Br content the lattice constants decrease and the transition temperature shifts from 274 to 170 K while the transition interval is broadened simultaneously. Single crystal investigations for x = 0.5 and 2.3, each at 110 and 298 K, indicate a preferred substitution of one of the bridging I positions (I6) by Br atoms.     

‘Hairdressing’ Shish-kebabs by melting

Summary A previous paper established the principle of hairdressing showing that polyethylene shish-kebab fibres can be reversibly transformed by appropriate preparation conditions between three morphologies, smooth fibres; fibres with closely spaced lamellar overgrowths; fibres with widely spaced lamellar overgrowths, where the spacing is sensitively affected by storage temperature (3). In the present paper this hairdressing work is extended to include the molten state. Three classes of morphology analogous to the three obtained from solution (although with certain minor differences) can be obtained by melting shish-kebabs at constant length, followed by quenching or isothermal crystallization. These melt-hairdressed fibres can be transformed back into shish-kebabs of typical solvent hairdressed appearance by the previously established procedures for solvent hairdressing. Thus all these works, following on from the trend established by Pennings (4), serve to highlight the fact thatall shish-kebabs acquire their external morphology at temperatures which are beneath those of the core formation during final cooling or storage and thatall external forms associated with a given core are interconvertible. On the molecular level these features highlight the intrinsically hairy nature of the core fibre as formed.With 5 figures     

Eisen- und Mangankomplexe mit sauerstoff-, schwefel- und methylen-verbrückten Distibanen und mit Chlorodiphenylstiban als Liganden

Complexes of Iron and Manganese with Oxygen-, Sulfur-, and Methylene-bridged Distibines and with Chlorodiphenylstibine as Ligands The photochemical reaction of CO₃Fe[P(OPh)₃]₂ and of MeCpMn(CO)₃ with the stibines Ph₂SbCl and (Ph₂Sb)₂X (X = O, S and CH₂) yields mononuclear complexes (CO)₂[P(OPh)₃]₂FeL and °Cp(CO)₂MnL (L = Ph₂SbCl, (Ph₂Sb)₂X) and the stibine bridged binuclear complexes °CO)₂[P(OPh)₃]₂Fe{(Ph₂Sb)₂X}Fe(CO)₂[P(OPh)₃]₂ and °Cp(CO)₂Mn{(Ph₂Sb)₂X}Mn(CO)₂MeCp.     

Stereoselective synthesis of tri- and tetrasubstituted oxepanes via n-Bu3SnH mediated 7-endo-trig vinyl radical cyclisation

A stereoselective 7-endo-trig cyclisation of homopropargyl and phenyl homopropargyl derivatives of Baylis-Hillman adducts using n-Bu₃SnH/AIBN mediated vinyl radical cyclisation affords tri- and tetrasubstituted oxepanes, respectively, in good yields.     

单羟基桥连的双铜(Ⅱ)大环穴醚配合物[Cu_2(OH)(ClO_4)(C_(16)H_(38)N_6)](ClO_4)_2·CHCl_3的合成和结构

本文合成了单羟基桥连的双铜(Ⅱ)大环穴醚配合物[Cu_2(OH)(ClO_4)(C_(16)H_(38)N_6)](ClO_4)_2 ·CHCl_3,并测定与讨论了它的晶体结构.晶体属于正交晶系,空间群为D_2~4 -P2_12_12_1,晶胞参数:a=12.749(4)(?),b=14.361(3)(?),c=18.064(3)(?),V=3307.3(13)(?)~3,Z=4。分子结构中单羟基桥连两个二价铜离子,Cu-O平均键长为1.935(6)(?),Cu-OH-Cu键角为135.2(2)°;铜原子的几何构型为畸变四方锥,配体的底面为穴醚的二乙三胺亚基的三个氮原子和一个羟基桥氧原子;顶点位置为高氯酸根的氧原子,因为该原子同时配位于另一个铜原子,所以分子的双铜中心存在第二个氧桥,即较弱的高氯酸根桥;Cu-O(ClO_3)距离分别为3.005(9)(?)和2.806(8)(?).     

Synthesis and transformations of 2-(5-amino-(mercapto)-1,3,4-thiadiazolylthio)-7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidines

The reactions of 2-amino-5-mercapto-(or 2,5-dimercapto)-1,3,4-thiadiazoles with 2-bromo-7-methyl-5-oxo-5H-1, 3,4-thiadiazolo[3, 2-a]pyrimidine to give the corresponding sulfides have been studied. The possibility of S-alkylation and addition of quinone at the free mercapto group in the 1,3,4-thiadiazole ring has been shown. The reactions at the amino group with benzoyl chloride and chloroformates have been investigated. The conditions of cyciodehydration at the amino group with ethyl acetoacetate and bromination of the pyrimidine fragment of 7-methyl-5-oxo-5H-1,3,4-thiadiazolo[3,2-a]pyrimidine have been found.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1954–1957, November, 1993     

Enthalpies of dilution of aqueous Li2B4O7 solutions at 298.15 K and application of ion-interaction model

The enthalpies of dilution have been measured for aqueous Li₂B₄O₇ solutions from 0.0212 to 2.1530 mol kg⁻¹ at 298.15 K. The relative apparent molar enthalpies, L_?, and relative partial molar enthalpies of the solvent and solute, and were calculated. The thermodynamic properties of the complex aqueous solutions were represented with a modified Pitzer ion-interaction model.     

Alternative products in one-pot reaction of benzylidenemalononitrile,N-methyl-2-thiocarbamoylacetamide,and ω-bromoacetophenone

N-Methyl-2-benzoylmethylsulfanyl-4-phenylnicotinamide and N-methyl-2-(4-phenyl-1,3-thiazol-2-yl)-acetamide have been obtained as alternative products to the desired N-methyl-2,3-dihydro-7H-thiazolo[3,2-a]pyridine-8-carboxamide by a one-pot cyclocondensation of benzylidenemalononitrile, N-methyl-2-thiocarbamoylacetamide, piperidine, and ω-bromoacetophenone. 2-Amino-1-methyl-6-oxo-4-phenyl-5-(4-phenyl-1,3-thiazol-2-yl)-1,6-dihydropyridine-3-carbonitrile has been obtained as main product by treatment of benzylidenemalononitrile with N-methyl-2-(1,3-thiazol-2-yl)acetamide. Dedicated to Professor I. Kalvinsh on his 60th birthday __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 777–781, May, 2007.     

Synthesis and rearrangements of 7H-pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]-and 7h-pyrrolo[3,2-e][1,2,4]triazolo[4,3-c]pyrimidines

7H-Pyrrolo[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines were synthesized by the reactions of 2-ethoxymethyleneamino-1H-pyrrole-3-carbonitriles with acid hydrazides and by the reactions of aminoiminopyrimidines (prepared based on the above-mentioned carbonitriles) with acid chlorides. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1438–1443, August, 2006.