16747-50-5Relevant academic research and scientific papers
Unusual, CO Assisted Cyclo-oligomerization Reactions of Ethylene: Formation of Cyclopentane and Cyclohexane Derivatives by Ytterbium Ziegler-Natta Catalysts
Keim, Wilhelm,Chen, Zhongxin,Shen, Zhiquan
, p. 1923 - 1924 (1989)
A new oligomerization of ethene to alkylcyclopentanes and/or alkylcyclohexanes using YbCl3/AlEtCl2 or ZrCl4/AlEtCl2 Ziegler-Natta type catalysts is described in which addition of carbon monoxide is essential.
Energy Well of Diradicals, VII. - Conjugative-Stabilized Trimethylenemethane Derivatives. Geometry Dependance of the Singlet-Triplet Splitting
Roth, Wolfgang R.,Winzer, Markus,Korell, Michael,Wildt, Holger
, p. 897 - 920 (2007/10/02)
For the three 2,1'-bis-allyl diradicals 3-5 the singlet-triplet splitting has been determined by the oxygen-trapping technique.In agreement with theory the value for the planar diradical is large (>14 kcal*mol-1) whereas for the orthogonal geometry the energy gap is small (6.3 kcal*mol-1).In all cases a triplet groundstate is observed.From the rotational barrier of the exo methylene groups in 6 it is shown that the interconversion of the planar and orthogonal singlet states have activation barriers (6-9 kcal mol-1) which are responsible for their kinetic stability.In contrast to 6, where the formation of the orthogonal diradical proceeds by way of the planar diradical 3, the formation of the analogous orthogonal diradical 29 from homofulvene 17 is a concerted process.This difference is an important observation with respect to the fundamental understanding of concerted and non-concerted reactions. - Key Words: Diradicals / Gas-phase kinetics / Oxygen trapping / Dynamic gas chromatography / Rotational barrier, two-step
