Carboxylation of styrene in the N(C4H9)4Br—heptane system

The carboxylation of styrene into carboxylic acids in the N(C₄H₉)₄Br—heptane system in the presence of phosphine complexes and palladium acetate was studied. In the absence of phosphine, the Pd catalyst seems to be stabilized in solution by forming anionic complexes with NBu₄Br; the stabilization depends on the acidity of the reaction medium. The catalytic system can be used repeatedly, its activity being reduced only slightly.__________Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2458–2461, November, 2004.     

Reactivity of the Indenyl Radical (C9H7) with Acetylene (C2H2) and Vinylacetylene (C4H4)

The reactions of the indenyl radicals with acetylene (C₂H₂) and vinylacetylene (C₄H₄) is studied in a hot chemical reactor coupled to synchrotron based vacuum ultraviolet ionization mass spectrometry. These experimental results are combined with theory to reveal that the resonantly stabilized and thermodynamically most stable 1-indenyl radical (C₉H₇^.) is always formed in the pyrolysis of 1-, 2-, 6-, and 7-bromoindenes at 1500 K. The 1-indenyl radical reacts with acetylene yielding 1-ethynylindene plus atomic hydrogen, rather than adding a second acetylene molecule and leading to ring closure and formation of fluorene as observed in other reaction mechanisms such as the hydrogen abstraction acetylene addition or hydrogen abstraction vinylacetylene addition pathways. While this reaction mechanism is analogous to the bimolecular reaction between the phenyl radical (C₆H₅^.) and acetylene forming phenylacetylene (C₆H₅CCH), the 1-indenyl+acetylene→1-ethynylindene+hydrogen reaction is highly endoergic (114 kJ mol⁻¹) and slow, contrary to the exoergic (−38 kJ mol⁻¹) and faster phenyl+acetylene→phenylacetylene+hydrogen reaction. In a similar manner, no ring closure leading to fluorene formation was observed in the reaction of 1-indenyl radical with vinylacetylene. These experimental results are explained through rate constant calculations based on theoretically derived potential energy surfaces.     

(C_5H_9C_5H_4)_3NdBrLi(THF)_3和(C_5H_9C_5H_4)_3SmTHF的合成与结构

无水三氯化钕与环戊烷基环戊二烯钠、溴化锂(1:2:1摩尔比)反应,除去不溶物和溶剂后,产物在己烷/四氢呋喃溶剂中冷冻得到兰紫色晶体(C5H9C5H4)3NdBrLi(THF)3(配合物1)。其中心金属Nd3+的配位数为10,以η5与3个环戊二烯基相连,并通过单溴原子桥连锂原子,形成双核结构。该晶体属三斜晶系,P`1空间群。晶体学参数为a=12.048(2)、b=13.498(3)、c=13.831(3);α=104.16(3)、β=104.07(3)、γ=95.96(3); V=2083.3(7)3、Z=2、Dc=1.35Mg/m3、Mr=847.01gmol-1、F(000)=874。无水三氯化钐与环戊烷基环戊二烯钠(1:3)反应,产物在-30oC下的己烷溶剂中结晶得桔红色晶体(C5H9C5H4)3SmTHF(配合物2)。该晶体属正交晶系,Fdd2空间群。晶胞参数a=28.175(5) 、b=46.24(2)、c=9.167(4);V=11943(8)3、Z=16、Dc=1.38Mg/m3、 Mr=622.11 g·mol-1、F(000)=5136。10配位的金属Sm3+与3个环戊二烯基以η5相连,并结合一个四氢呋喃溶剂分子。     

Syntheses and Crystal Structures of Complexes [Cu(C14H8N3O4Br)](C4H9NO) and [Ni(C14H9N2O3Br)](C4H9NO)

The title compounds, Cu(L1)(C4H8NHO) and Ni(L2)(C4H8NHO) (H2L1 = 5-bro- mosalicylaldehyde-p-nitrobenzoylhydrazone, H2L2 = 5-bromosalicylaldehyde-p-hydroxybenzo- ylhydrazone), have been obtained and characterized by single-crystal X-ray diffraction. Complex 1 belongs to the triclinic system, space group P1 with a = 8.6960(2), b = 9.957(2), c = 11.878(2) , α = 73.36(3), β = 78.25(3), γ = 82.64(3)o, V = 962.1(3) 3, Mr = 512.81, Z = 2, F(000) = 514, Dc = 1.770 g/cm3, μ(MoKα) = 3.251, R = 0.0337 and wR = 0.0846. Complex 2 is of monoclinic, space group P21/c with a = 13.313(2), b = 8.2096(1), c = 21.890(3) , β = 125.737(3)o, V = 1941.9(4) 3, Mr = 478.97, Z = 4, F(000) = 968, Dc = 1.638 g/cm3, μ(MoKα) = 3.085, R = 0.0356 and wR = 0.0817. The ligands form a satisfactory N2O2 square plane around the metal centers in two compounds. Different patterns of hydrogen bonds are observed owing to the presence of different substituents on aromatic ring of the acylhydrazone Schiff bases. In complex 1, square-planar copper(II) complexes are linked by intermolecular hydrogen bonds leading to zigzag infinite chains. In complex 2, the metal complexes are linked via hydrogen bonds to form corrugated sheets in a staggered fashion; 3D channels along the b axis are constructed through other non-covalent interactions between the neighboring layers.     

四氯合锌酸十四烷铵-四氯合锌酸十六烷铵二元体系相图

合成了四氯合锌酸十四烷铵(C4H29NH3)2ZnCl4(简记为C14ZnCl)和四氯合锌酸十六烷铵(C16H33NH3)2ZnCl4(简记为C16ZnC1),并配制了一系列不同组成的C14ZnCl-C16ZnCl二元体系,通过DSC测试,变温红外光谱法及X-ray粉末衍射法来绘制该二元体系相图。该相图是生成稳定中问化合物的固相部分互溶体系相图。     

STRUCTURE OF BIS(QUINOLINE-8-OLATO)DIBUTYLTIN(IV)[Sn(C4H9)2(C9H6NO)2]

<正> INTRODUCTION. Studies of six-coordinated diorganotin(Ⅳ) compounds with octahedral geometry have been widely made, which indicate that the transor distorted trans [SnR_2] unit is common for the dialkyltin(Ⅳ) species     

Monocarbaborane anion chemistry. An interesting encapsulation of the Pd2I2(P(C6H(4)-4-Me)3)4]2+ cation by a pair of [PhCB9H4I(C6H4Me)4]- anions

Reaction of the [1-Ph-closo-1-CB9H(4)-6,7,8,9,10-I5]- anion with 4-MeC6H4MgBr in the presence of [PdCl2(PPh3)2] gives the [Pd2I2(P(C6H(4)-4-Me)3)4]2+ salt of the [1-Ph-closo-1-CB9H(4)-10-I-6,7,8,9-(C6H(4)-4-Me)4]- anion, which exhibits an unusual neutral supramolecular assembly in the solid state, in which the dipalladium dication is encapsulated by two four-armed 'tetrapus' anionic units; the anion also has potentialities for four-fold dendrimer construction.     

Clathrate formation in the liquid phase of (C4H9)4NF−NH4F−H2O

At a certain concentration of NH₄F, the solid allocyric solutions of the (C₄H₉)₄NF−NH₄F−H₂O system stratify into two liquid phases in the process of melting. The mutual solubility of the liquids decreases at elevated temperatures. The boundary surface of the stratification region was determined The solubility isotherms (27 and 30°C) of the stratification region are investigated by the solubility method This relatively rare mutual sulubility of liquids (retrograde solubility) is associated with clathrate formation in the liquid phase. Near the melting points of the solid clathrate solutions, both in the liquid and solid phases the tetrabutylammonium cation evidently forms surrounding cavities bounded by water and ammonium fluoride molecules linked by hydrogen bonds. The clathrate-like components of the solution are structurally compatible with “water-like” and “organic” components, i.e., they are homogenizing components. At higher temperatures, the homogenizing clathrate-like structures break down, and the structurally incompatible solution components stratify into two phases. Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences. Translated fromZhurnal Strukturnoi Khimii, Vol 35, No. 6, pp. 122–128, November–December, 1994. Translated by L. Smolina