Competing pathways in the photolysis of bicyclo[1.1.0]butane
作者:Alan F. Becknell、Jerome A. Berson、R. Srinivasan
DOI:10.1021/ja00290a063
日期:1985.2
Obtention par photolyse UV, dans le cyclohexane ou l'heptane, du butadiene-1,3 et du cyclobutene. Mecanismes faisant intervenir deux etats excites voisins du bicyclo [1.1.0] butane
获得光解 UV、dans le 环己烷 ou l'heptane、du butadiene-1,3 和 du cyclobutene。Mecanismes faisant intervenir deux etats 激发voisins du bicyclo [1.1.0] 丁烷
Ru(0)-Catalyzed Straightforward Synthesis of Conjugated Tetraenes: An Approach using Two Internal Alkynes with 1,3-Butadiene
作者:Sayori Kiyota、Masafumi Hirano
DOI:10.1021/acs.organomet.7b00801
日期:2018.1.22
The Ru(0)-catalyzed straightforwardsynthesis of conjugated tetraenes has been achieved in up to 85% yield by coupling of 2 equiv of internal alkynes with 1,3-butadiene at room temperature. The stoichiometric reaction of [Ru(η4-cisoid-1,3-butadiene)(η4-1,5-COD)(NCMe)] with 2 equiv of 3-hexyne produces a tetraene complex of Ru(0), [Ru3–6-η4-(3E,5E,7E,9E)-4,9-diethyldodeca-3,5,7,9-tetraene}(η4-1,5-COD)(NCMe)]
Preparation of 1, 1-difluorobenzocyclopropene (4) and of its 2, 5- and 3, 4-dideuterio derivatives 4a and 4b is reported. Upon ionization in cold fluorosulfonic acid, 4 affords 1-fluorobenzocyclopropenium ion (6). 1H- and 13C-NMR. spectra of 4 and 6 are assigned on the basis of the data for the specifically deuteriumlabelled compounds 4a and 6a. Hydrolysis of 6a leads to 2, 5-dideuteriobenzoic acid
Diblock Copolymer Reinforced Interfaces between Amorphous Polystyrene and Semicrystalline Polyethylene
作者:J. J. Benkoski、P. Flores、E. J. Kramer
DOI:10.1021/ma034013j
日期:2003.5.1
increasing Mn. The detection of deuterium on the fracture surfaces indicated that pullout of the PE block was the predominant failure mechanism when Mn ≤ 30 kg/mol. Only when the molecular weight of the PE block reached 85 kg/mol was failure by chain scission observed. Since the entanglement molecular weight of PE is approximately 1 kg/mol, interfacial reinforcement does not appear to depend on the
在聚苯乙烯(PS)和聚乙烯(PE)之间的二嵌段共聚物增强的界面上探讨了分子结构对半结晶聚合物断裂性能的影响。用于这项研究的PE是一种模型乙烯-丁烯共聚物,其选择是因为它与氢化的1,4-聚丁二烯具有相容性。这种相容性允许使用氢化的聚(苯乙烯-b -1,4-四氘代丁二烯)作为嵌段共聚物。对于一系列这类双嵌段共聚物,系统地改变了面链密度(Σ)和PE嵌段的分子量(M n),以观察其对界面断裂能(G c)的影响。在低Σ时,G c保持相对恒定,大约为1 J / m 2。超过Σ的临界值,断裂能迅速攀升。该临界值随M n的增加而降低。断裂表面上氘的检测指示的PE块的该拉出是主要的失效机理时中号Ñ ≤为30kg /摩尔。仅当PE嵌段的分子量达到85kg / mol时,才观察到由于断链而失败。由于PE的缠结分子量约为1 kg / mol,因此界面增强似乎不取决于该系统的缠结形式。关键的中号ñ而是与PE块的均方
Microwave measurements of the rotational spectrum and structure of butadieneiron tricarbonyl
作者:S. G. Kukolich、M. A. Roehrig、D. W. Wallace、G. L. Henderson
DOI:10.1021/ja00058a058
日期:1993.3
The rotational spectra or 10 isotopomers or (butadiene)iron tricarbonyl were measured using a Flygare-Balle-type microwave spectrometer operating in the 5-17-GHz frequency range. The 30 measured rotational constants were used to determine 12 gas-phase structural parameters describing the cis-butadiene conformation and the locations and orientations or the butadiene and CO ligands relative to the iron
使用在 5-17 GHz 频率范围内运行的 Flygare-Balle 型微波光谱仪测量旋转光谱或 10 种同位素异构体或(丁二烯)三羰基铁。使用 30 个测量的旋转常数来确定 12 个气相结构参数,这些参数描述了顺丁二烯构象以及位置和取向,或丁二烯和 CO 配体相对于铁原子。Kraitchman 分析或这些微波测量,使用单个和多个氘取代,提供关于复合物中氢原子坐标的准确数据。发现末端 CH 2 基团或丁二烯旋转 28 o 出或丁二烯平面,并且 CH 2 平面在远离离子原子的方向上折叠远离 C 1 -C 2 轴 27 o