Crystal-Lattice Controlled Photopolymerization of Di(benzylammonium) (Z,Z)-Muconates

Abstract

A new type of photoreaction of the ammonium salts of butadiene-1,4-dicarboxylic acid in the solid state is reported. When the crystals of a series of di(benzylammonium) (Z,Z)-muconate (2,4-hexadienedioate) and its related derivatives were prepared and photoirradiated, either a tritactic polymer or an (E,E)-isomer was obtained as the photoproduct according to the structure of the ammonium part. The polymers produced were confirmed to be of high molecular weight and stereoregular by viscometry and NMR spectroscopy after solidstate polymer transformation. X-ray crystal structure analysis revealed that the crystal structures of benzylammonium muconates were classified into columnar-type and sheet-type on the basis of the molecular arrangement. Both types involve two-dimensional hydrogen bond networks between the primary ammonium cations and the carboxylate anions. In the former structure, the stacking of the diene moieties was suitable for topochemical polymerization to yield a tritactic polymer, while the latter has molecular packing favoring the isomerization or no reactivity. The stereocontrol of the tritactic polymer is in good agreement with the results expected from the crystal structure. This indicates that the molecular packing determines a reaction pathway in the crystalline state.

Polymer Structure Control Based on Crystal Engineering for Materials Design

“…The 4-methoxybenzyl ester of (E, E)-muconic acid (3a) provides a disyndiotactic polymer with a structure identical to that obtained from the (Z, Z)-muconic ester (1e). 43 Similarly, some ammonium derivatives of (Z, Z)-muconic acid topochemically polymerize (2a-2k), [44][45][46] several others isomerize, and all the others are photo-inactive. The corresponding ammonium (E, E)-muconates are stable under photoirradiation except for di(1-naphthylmethylammonium) (E, E)-muconate (4a), which readily polymerizes similarly to the (Z, Z)-muconate one (2k).…”

Inclusion Polymerization in Polymorphic Crystals of Cholic Acid

“…4 In these assemblies, monomers are arrayed in a specific direction by noncovalent interactions, such as hydrogenbonding and van der Waals interaction, to give characteristic polymers. In particular, some solid-state polymerizations provide clear relations between the orientation of monomers and stereoregularity of the resulting polymers.…”

“…In particular, some solid-state polymerizations provide clear relations between the orientation of monomers and stereoregularity of the resulting polymers. 4 Inclusion compounds are useful assemblies for controlling the orientation of monomer molecules. 5 Nanometer-level spaces of the compounds force guest molecules to be arranged in a specific direction.…”

Solvent-Free Synthesis of Layered Polymer Crystals

“…7,8 The polymer crystals are obtained from the topochemical polymerization of alkylammonium muconates and the subsequent hydrolysis. 9 All the topochemically polymerizable monomer crystals of alkylammonium salts have a layered structure; the layer of muconate dianions is sandwiched with the layers of alkylammonium cations. [9][10][11] The layered structure is preserved during the polymerization and the subsequent transformation.…”

“…9 All the topochemically polymerizable monomer crystals of alkylammonium salts have a layered structure; the layer of muconate dianions is sandwiched with the layers of alkylammonium cations. [9][10][11] The layered structure is preserved during the polymerization and the subsequent transformation. The intercalation system is important to synthesize functional polymer crystals that cannot be obtained by the direct topochemical polymerization in the crystalline state.…”