Optically active hydrocarbon polymers with aromatic side chains. III. Circular dichroism between 230 and 185 nm of the aromatic chromophore in high molecular weight hydrocarbons

Abstract

HC^r-Com(CN)2(PEt3)2 CH2 7 + OH(5)4. The trapping of 6 by CO results in the regeneration of 1 and thus provides the basis for a catalytic cycle, i.e., 1 3 (5) -6 -1, in which the oxidation of CO by Fe(CN)e3proceeds readily under the catalytic influence of 1, i.e. CO + 2Fe(CN)6=-+ 40H~-U-C032" + 2Fe(CN)e4-+ 2H20 (6) 26600) and the National Institute of Arthritis and Metabolic Diseases (AM 13339) is gratefully acknowledged.13 Hz, CHH'), 3.72 (2 H, d, / = 7 Hz, CHH'), 5.4 (1 H, m, CH). The -allyl region of the nmr spectrum resembles that of other -allyl complexes.9

Optically active copolymers from p‐vinyltrifluoroacetophenone

“…In principle the CD induced in the trifluoroacetylphenyl (TFA) chromophore should derive from two main contributions, the one due to the isolated VTFA units and the other, to interactions between chromophores of different units in a mutually dissymmetric disposition. 16 The occurrence of the former has been clearly demonstrated in styrene/( -) -menthylacrylate alternating copolymers1 * and should be substantially independent of composition, at least when more than 50 mol % optically active comonomer units are present in the cop01ymer.l~ As far as the shape of the CD curve is concerned, this contribution is characterized by a single dichroic band at the same wavelength as the absorption maximum. The other contribution has been observed in many coisotactic copolymers of vinylaromatic monomers with optically active a-olefinsls and is related to exciton splitting due to electronic transition moments of the chromophoric groups of the different units.…”

Odd−Even Effect in Free Radical Polymerization of Optically Active 2,5-Bis[(4‘-alkoxycarbonyl)- phenyl]styrene

“…The absence of the Cotton effect of S -(+)-M0 is probably due to the fact that its chiral centers are far away from the p -terphenyl group. The apparent difference between the CD spectra of S -(+)-M0 and S -(+)-P0 demonstrates that the side p -terphenyl groups are arrayed in a skewed way along the polymer backbone. − The chiral perturbation of an aromatic group as in ( S )-2-phenyl-3,3-dimethylbutane can also give rise to enhanced Cotton effects due to the smaller conformational mobility of phenyl ring . However, the existence of electronic interactions between aromatic groups with a fixed mutual geometrical disposition along the helical chain supplies additional rotatory strength and splits the electronic transitions, particularly to those having larger polarizability .…”

Optically active hydrocarbon polymers with aromatic side chains. 12. Synthesis and characterization of coisotactic copolymers of (S)-4-methyl-1-hexene with styrene

“…A more detailed and accurate description of copolymer microstructure can be gained by a 13C NMR investigation, which will be the subject of a later paper.17 ether-polyether block copolymer can be obtained.3 More recently, (TPP)AICI has been found to exhibit high catalytic activity for the polymerization of /3-propiolactone and /3-butyrolactone to provide the corresponding polyester with well-controlled molecular weight and narrow molecular weight distribution. 4 The propagating end group in this polymerization has been established to be a (porphinato) aluminum carboxylate5 (Scheme I).…”