Novel dibenzocycloheptenyl phosphonium salts as thermolatent initiator in cationic polymerization

Abstract

In this study, novel thermolatent cationic initiators based on dibenzocycloheptenyl phosphonium salts (1a, 1b, 1c, 1d, 2a, and 3a) were synthesized and their efficiency was examined in bulk polymerization of glycidyl phenyl ether (GPE). The polymerization of GPE was performed with 1 mol % of dibenzocycloheptenyl triphenylphosphonium salts (1a-1d) with different counter anions (SbF 6 À , PF 6 À , AsF 6 À , and BF 4 À ) at 25-200 C for 1 h. The order of initiator activity was found as 1a > 1d > 1b > 1c . To examine the effect of phosphine moiety, the activity of 1a was compared with dibenzocycloheptenyl-tri-nbutylphosphonium hexafluoroantimonate (2a). The order of initiator activity was observed as 1a > 2a. The initiator activity of 1a was compared with that of 10,11-dihydrodibenzocycloheptenyltriphenylphosphonium hexafluoroantimonate (3a) to understand the effect of extended conjugation in dibenzocycloheptenyl ring. In general, with the increase in the polymerization temperature, conversion (%) also increases. The solubility of initiators in various solvents and epoxy monomers was also examined.

Sterically and Electronically Modified Aryliminopyridyl-Nickel Bromide Precatalysts for an Access to Branched Polyethylene with Vinyl/Vinylene End Groups

“…Ni(1) deviates at 0.152 Å from the coplane consisting N(1), C(5), C(6), and N(2). There is no direct bonding between the nickel atoms; however, the intermolecular distance of Ni1···Ni1 i was observed to be 3.544 Å. ,,,− Furthermore, the Ni(1)–N(1) pyridine bond length (2.042(3) Å) is shorter than the Ni(1)–N(2) imine bond length (2.102(3) Å), indicating the better donor capability of the pyridine nitrogen atoms. − ,,,,, …”

“…In the present work, we are developing dibenzocycloheptyl groups as the counterpart of dibenzhydryl groups in D and E or fluorenyl groups in F (Chart ); we assumed that the steric effect, as well as acidity of methine protons in 2,4-bis­(dibenzhydryl)-6-R-imine and 2,4-bis­(fluorenyl)-6-methyl-imine along with variable steric/electronic properties of the ortho-position near the central metal may have some influence on the catalytic performance and polymer properties . In this regard, we report 2-(2,4-bis­(dibenzocycloheptyl-6-R-phenylimino)­ethyl)­pyridine-nickel precatalysts ( G , Chart ), where R = Me, Et, i -Pr, Cl, and F. The influence of the steric and electronic properties of the ortho-substituent was investigated and then catalytic evaluation of G was investigated in depth that is how the co-catalyst as well as reaction parameters can impact the catalytic performance and properties of the resulting polyethylene.…”

Remote dibenzocycloheptyl-substitution of an iminotrihydroquinoline-nickel catalyst as a route to narrowly dispersed branched polyethylene waxes with alkene functionality

“…In this article we are concerned with developing the dibenzocycloheptyl counterpart of fluorenyl F (Chart 1) as we suspected that the high acidity of the fluorenyl methine proton in F may have had some impact on the polymerization performance [26]. Specifically, we report a family of para-dibenzocycloheptyl-substituted 8-arylimino-5,6,7-trihydroquinoline-nickel complexes (G, Chart 1) in which the steric and electronic properties of the ortho-R groups will be varied.…”

Control of reactions and network structures of epoxy thermosets

“…To the best of our knowledge, the last new thermal latent onium salts were reported by Gupta and coworkers in 2009 [359][360][361]. The future of this research field will be dependent on the development of molecular structures with highly effective latent properties in very moderate temperature ranges.…”