We have found a simple and novel synthetic method for obtaining a chiral polymer from an achiral monomer by using a chiral catalytic system. The chirality of the polymer was caused only by a one-handed helical backbone, and the polymer had no other chiral structures in the side groups. In addition, the helical conformation was stable in solution by itself. This is the first example of helix-sense-selective polymerization of a substituted acetylene. The stability of the helicity was found to be caused by intramolecular hydrogen bonds.

A novel, highly selective photocyclic aromatization (SCAT) of π-conjugated polymers from phenylacetylene having two hydroxyl groups to exclusively yield a 1,3,5-trisubstituted benzene derivative was developed, and its success was confirmed by (1)H NMR, GPC, and TOF-MS. The SCAT reaction has many unique characteristics. (1) It is a quantitative reaction: it gave only the corresponding cyclic trimer, i.e., a 1,3,5-trisubstituted benzene derivative, quantitatively (100%). No byproducts were produced under the best conditions. (2) It is an intramolecular reaction: it occurred between three adjacent monomer units in one macromolecule. (3) It is a stereospecific and topochemical or template reaction: the reactivity strongly depended on the configuration and conformation of the starting polymer substrates. (4) It is a photoreaction: high selectivity (100%) was observed only by the use of visible light irradiation, not by heating. (5) It is a solid-state reaction: high selectivity (100%) was observed only in the solid state, not in solution. In addition, (6) the resulting cyclic trimers could form a self-supporting membrane, despite their low molecular weights. This new approach resulted in a new class of supramolecular polymers consisting of a 1,3,5-trisubstituted benzene derivative, numbers of which were linearly linked by hydrogen bonds and stacked benzene derivatives. Since SCAT has such high selectivities and is useful for the preparation of a self-supporting supramolecular polymer membrane, many applications can be expected.

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The pure-gas permeation and sorption properties of poly [1-phenyl-2-[p-(trimethylsilyl)phenyl]acetylene] [PTMSDPA] are presented and compared to those of poly(1-trimethylsilyl-1-propyne) [PTMSP], poly(4-methyl-2-pentyne) [PMP], and poly(1-phenyl-1-propyne) [PPP]. PTMSDPA is more permeable to large, condensable vapors (e.g., n-butane) than to small, permanent gases (e.g., hydrogen). Such behavior is also observed in PTMSP and PMP but not in PPP. PTMSDPA has lower fractional free volume (0.26) and gas permeabilities than PTMSP and PMP. However, relative to conventional glassy polymers, PTMSDPA is a highly permeable, high free volume, glassy material. For example, the oxygen permeability coefficient of PTMSDPA is 1200 × 10 -10 cm 3 (STP)‚cm/(cm 2 ‚s‚cmHg) at 25 °C. As temperature increases, the permeability in PTMSDPA increases for light gases (helium, hydrogen, and nitrogen) and decreases for more condensable gases. In contrast, the permeabilities of PTMSP and PMP decrease with increasing temperature for both light gases and more condensable hydrocarbons. n-Butane and propane sorption isotherms for PTMSDPA are concave to the penetrant relative pressure axis, consistent with dual-mode sorption behavior. Hydrocarbon sorption levels decrease in the order PTMSP > PMP > PTMSDPA > PPP, in agreement with the ranking of the fractional free volumes of the materials.