Stereoregularity in ionic polymerization of acenaphthylene

Abstract

(Novc mbcr 15, 1963) F our distinct polym.crs wc rc isolated fr om t he p olym eri zat ions of accnaph Lh.v lcnc ill it iated by boron t rifiu oride a nd n-butyllithium. A syn d iotactic or isotactic co nform atio n was assigned to t h ese prod ucts on t he basis of infrared a nd N M R evidence. T he conformat ions and reaction details a re di sc ussed. I . IntroductionA survey of the fi eld of ster eor egulm' polym ers indicated th at little h as been don e in delib er at e control of chain conformation by mea ns of steric hindmn ce of bulky groups [1] .1.2 In t his sense, acenap hLl1 ylene as a vin yl mon om er Wt1S parli culnrly int eresLin g du e Lo the extreme bulk fi nd rigidit y of the 1 ,8 -pel"in~tph t h yle n e residue. Addition al feftt ures wer e its slm in ed five -mem bered ring [b ] and well defin ed co nditi ons for polYllleri zfl tio li.Th e polymers of ftcenflpil thylene h ftve been exte nsively investi gated. D ziewonski and his coworke rs [2] we re able to show iO llic, therm ftl, ftll d solicl-st~l te polymerizat ion of ace lHlphlhylene before t he prese nt-day tools for m easuring Jl igh molecular weights were available. Their investigl1tio ns started in 1912 rmel ended in ] 924. Since then, oL her work· ers have examin ed these polymers. Jones '.:vote adclecl ill proof: The paper by G. Nalla, G . Dall' Asta, G. M azzanti, ancl G . Metroni (Mukro11l01. Cilelll. 69 , 124, 1963) describes the polymerization of cyclobutcnc with Ziegler cMa lysts. The ste reochemistry of t hc products arc ap parently identical with the case described hero. Instead of cis or trans, the nomenclature tILTeo or eTl/tltro, rrs pcctivl'iy, is used. 165th e plftl1e of t.he papcr a,nd tll e B 's are ill fl p ara llel plan e b elow, was self-termin ati ng . Ri ll g Jormat.ion was fftvo red . I n fact, both a cyclic trimer and tetranw r ftre kn own [2}. The cis-sy ndiolactic p olymer II was impossible to con str uct beyond th e Lrimer. IIT he Silme nolation is used here ,1S for J ~lbove.The A's werc acLuftlly Lwisled out of plane due Lo storic hindrance. trans-Iso tactic poJ~-acenaphLhy lene, lIT , for med a helix. 3 III 3 'r'he limited rotation about the back bone carbon-carbon bonds due to stcric hind rance of the 1,8-acenaphthylcnc residues suggests that change in the se nse of the helix of III is not possible if a penultimate effect in fl uences the course of add ition. Of course, a mixture of d a nd 1 cha ins would be produced, unless a n assynlctric initiator wcro used.

Identification of the short-range intramolecular excimers in polyacenaphthalene

“…In another study, the effect of temperature on the dynamics of excimerforming probe molecules dispersed in polypropylene oxide) has been measured. 8 This study indicated that the excimer dynamics probed the local scale polymer dynamics and that the results were consistent with the WLF equa-…”

Synthesis and characterization of optically active copolymers of acenaphthylene. 1. Preparation and characterization

“…The cis stereoisomers could not be obtained beyond trimer or tetramer. 23 In the present work, the occurrence of only one band at 2895 cm'1 in poly(l) and in copolymers with 1 content higher than 90 mol % would indicate an essentially trans-disyndiotactic configuration also for free radical hompolymer and copolymers. Unfortunately, the IR spectra of copolymers in the same region are complicated by the presence of overlapping bands due to the C-H stretchings of comonomers 2 and 3, thus not permitting a detailed investigation by this technique.…”

“…The present results confirm the general trend shown by 1 in the free radical copolymerization. It is, however, fair to mention that the bulkiness of the menthyl group in itself might play some + [3] = 1.0 M; comonomers/AIBN molar ratio = 100; polymerization time [20][21][22][23][24][25] h. b Calculated as [(weight of solid polymer)/(weight of starting comonomers)] X 100. 0 Determined by NMR and UV spectroscopy.…”

Synthesis and characterization of rigid‐chain polyacenaphthylene

“…According to Story and Canty [ 3 ] , the 2895 cm-I band is due to the threodisyndiotacticity of this polymer, which leads us to conclude that the polymer prepared by emulsion polymerization has predominantly the same configuration.…”