Formation of Bundle Assemblies of Stereoregular Polymers in Thermal Solid-State Polymerization of 7,7,8,8-Tetrakis(aryloxycarbonyl)-p-quinodimethanes

Abstract

7,7,8,-p-quinodimethanes with bulky aryloxy groups such as benzyloxy (1a), pentafluorobenzyloxy (1b), and both benzyloxy and pentafluorobenzyloxy (1c) were synthesized. We investigated effects of these bulky groups on thermal solid-state polymerization reactivities on the basis of crystal structures of 1a−1c. Thermal polymerizations gave 1,6-trans-type stereoregular polymers in quantitative yields in 1 day at 110°C for 1a, 1 day at 150°C for 1b, and 6 days at 110°C for 1c. Their initial crystal shapes were retained in appearance during polymerization to yield solid bundle assemblies of their polymeric chains. X-ray single-crystal structure analysis indicates that their crystals adopt molecular arrangements suitable for one-dimensional polymerization with the 1,6-trans-type addition along one crystallographic axis. Such arrangements led to expansion polymerization of 1b and contraction one of 1c. The resulting stereoregular polymers form less ordered bundle assemblies than those prepared by the conventional topochemical polymerization. In this manner, the bulky aryloxy groups enabled us to observe a close relation between the molecular assembly modes and the polymerization behaviors, providing the first example for proving diversity of thermal solid-state polymerizations.

Solution-processable and functionalizable ultra-high molecular weight polymers via topochemical synthesis

“…After polymerization, crystals of P1 and P2 become insoluble, while those of P3 readily dissolve in many common mid-range polarity organic solvents. In contrast to previously reported TCP systems—including the closely related substituted para -quinodimethanes and quinone methides—the solid-state reactivity of diphenylidine-substituted AQMs were surprisingly forgiving to the inclusion of long alkyl groups 9 , 35 , 36 , 40 , 41 . Additionally, unlike many other methods of producing UHMW polymers, this method is insensitive to the presence of water and oxygen and requires no catalysts or auxiliaries 54 – 57 .…”

“…In contrast to monomers 1 – 3 , the reactive methylene carbons on each molecule of 4 are not close enough to either of its neighbors’ to allow for TCP. Large d CC values of 4.98(3) and 5.13(8) Å—depending on which methylene carbons are presumed to react—are found in the solid-state of 4 , which are significantly larger than those in monomers 1 – 3 and other polymerizable examples in the para -quinodimethane family and explain its lack of topochemical reactivity 9 , 35 , 36 , 40 , 41 .

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“…1 and Supplementary Fig. 3 , and Supplementary Movie 1 ) 9 , 35 , 41 . The solid-state reactivity of the phenyl-substituted AQM monomers 1 – 3 differs from the monomer 4 , which is not affected by light and/or heat.…”

“…TCP reactions are relatively rare, however, due to the fact that TCP monomers must crystallize such that the distances between their reactive sites (d CC s) are small enough to allow for their polymerization to proceed without significant movement or deformation in each of the monomers 1 , 3 , 4 , 9 . The vast majority of examples make use of two categories of reactions: cycloaddition reactions that involve polyolefins 10 – 13 , oligo(aza)anthracenes 14 – 17 , alkynes/azide 18 – 21 and alkene/azides 22 ; and addition reactions between reactive groups, such as diynes 3 , 6 , 23 – 25 , triynes 26 – 28 , dienes 29 – 32 , trienes 33 , para -quinodimethanes 9 , 34 – 41 and bis(indanone)s 8 , 42 , 43 . In addition to linear polymers, TCP reactions have also been used to produce a number of intriguing extended materials, such as porous 2D 25 , 42 , 44 – 51 and 3D polymer crystals 52 .…”

Self‐Assembly Behavior of Diacetylenic Acid Molecules upon Vapor Deposition: Odd–Even Effect on the Film Morphology

“…It has long been known that certain types of diacetylenicmolecules in their crystalline state can undergo "topochemical polymerization" reactions, from which ac onjugated poly(ene-yne) chain system is producedwith little perturbationo ft he original crystal packing arrangement in the system. [1][2][3] As pecific packing distance and relative tilt angle between the neighboring diacetylene units are necessary for this 1,4-additionr eaction to proceed upon UV irradiation or heat treatment. [4][5][6] Owing to their unique electronic and opticalp roperties, the resultant polydiacetylenes have been much explored for their applicationsi nawide range of areas.…”