75211-14-2Relevant academic research and scientific papers
Controlled molecular design of ether- and ester-bridged norbornenes and their ring-opening metathesis polymerizations
Abd-El-Aziz, Alaa S.,Edel, Andrea L.,May, Leslie J.,Epp, Karen M.,Hutton, Harold M.
, p. 1797 - 1809 (1999)
A series of functionalized polynorbornenes containing pendent ether- or ester-bridged poly(aromatic ether) chains were prepared. The ether-bridged norbornene complex was synthesized via cyclopentadienyliron-mediated nucleophilic aromatic substitution reactions. This methodology, combined with that of dicyclohexylcarbodiimidemediated coupling, allowed for the formation of novel oligomeric aryl ether and ester substituted norbornene complexes. Photolytic demetallation gave the monomers in good yields. Structural identification of the exo and endo isomers of both the metallated and demetallated norbornene derivatives was accomplished using HH and CH COSY NMR techniques. Ring-opening metathesis polymerization (ROMP) of these monomers using RuCl3(hydrate) and (Cy3P)2Cl2Ru=CHPh allowed for the preparation of the functionalized polynorbornenes. Thermal analysis of the resulting polymeric materials demonstrated greater thermal stability as the number of aryl ether groups increased.
Kinetics and mechanism of acid-catalyzed hydration of 5-hydroxymethyl- and 5-phenoxymethylnorborn-2-enes
Lajunen, Martti,Latva-Nirva, Esa
, p. 719 - 723 (2007/10/03)
The disappearance rate constants for exo- and endo-5-hydroxymethylnorborn-2-enes (3 and 4) and exo- and endo-5-phenoxymethylnorborn-2-enes (5 and 6) were measured in aqueous perchloric acid by a capillary GC method at different temperatures and acid concentrations. The rate constants, activation parameters, excess acidity plots and products (for 3 and 4 only) are in agreement with the rate-determining protonation of the double bond (AdE2 mechanism). No proof of endo protonation of the double bond via the protonated endo-5-CH2OH group was obtained. The excess acidity plots were corrected according to the partial protonation of the hydroxylic or ether oxygen atom. In the case of 3 and 4, the slope parameter m?, indicative of the transition state, decreases slightly with increasing temperature, the intercept parameter log (ko/M-1s-1) depends reasonably on the temperature, and the protonation site parameters of the hydroxymethyl group, m′ and pKS′H+, are temperature-independent. The corresponding parameters for 5 and 6 at 303 K are normal except the peculiar pKS′H+ values, ca. -2.5.
