Thermal Reaction of a Columnar Assembled Diacetylene Macrocycle

Abstract

Reported is a macrocyclic diacetylene that assembled into columns to afford porous crystals. Heating this assembly initiated a topochemical polymerization of the preorganized diacetylene units to give covalent conjugated polydiacetylenes. These stable conjugated materials maintained permanent porosity as evidenced by their type I gas adsorption isotherms with CO(2) (g). Such conjugated polymeric nanotubes could possess unusual properties for sensing and electronics.

Synthesis, Gelation Properties and Photopolymerization of Macrocyclic Diacetylenedicarboxamides Derived from L‐Glutamic Acid and trans‐1,4‐Cyclohexanediol

“…The intermolecular distances of N···O are estimated to be 2.97, 3.01, 2.98 and 2.99 Å, and the lengths indicate the formation of hydrogen bonds. [16] Most importantly, the macrocyclic rings stack face-to-face infinitely along the a axis, providing a tubular assembly in the solid state similar to the findings of a previous study by Xu et al [10] Therefore a similar face-to-face stacking and nanotubular structure established through hydrogen-bonding in the gel state of the other macrocyclic diacetylenes can be expected. Unfortunately, we could not obtain direct evidence for the forma-tion of the covalently linked nanotubes of 4b because this crystal did not polymerize upon photoirradiation.…”

“…X-ray crystallographic analysis of this compound clearly showed the tubular assembly of the macrocycles and thermal reaction of the solid provided insoluble oligo-or polydiacetylenes that showed permanent porosity. [10] In this study we planned to construct nanofibrous and -tubular structures in the gel state by the non-covalent self-assembly of macrocyclic diacetylene compounds as organogelators. The stabilization of the self-assembled structures by covalent bonds through the polymerization of the diacetylene moieties was also examined.…”

Porous organic molecular solids by dynamic covalent scrambling

“…Unlike porous molecular crystals [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] , these amorphous solids comprise a distribution of molecular species, which can be controlled by the diamine feed ratio (Fig. 3a).…”

“…Calixarenes, in particular, can exhibit 'porosity without pores' 10,11 : that is, the solid materials can adsorb guests by cooperative diffusion, despite having isolated voids rather than interconnected pore structures. Permanent, interconnected porosity in discrete organic molecules with low molar mass is rarer 11 and is typically confined to certain ordered molecular crystals [12][13][14][15][16][17][18][19][20][21][22][23][24] . Examples include modified calixarenes [12][13][14] , 3,3′,4,4′-tetra(trimethylsily lethynyl)biphenyl 15 , tris-o-phenylenedioxycyclotriphosphazene 16 , 4-hydroxyphenyl-2,3-4-trimethylchroman 17 , cucurbit [6]uril 18 , some dipeptides 19 , diyne macrocycles 20 and imine-linked porous organic cages 21,22 .…”

“…There has been less focus here in comparison with the preparation of ordered porous solids using crystal engineering [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] . Polymers of intrinsic microporosity (PIMs), for example, form amorphous microporous solids-that is, amorphous solids with pore dimensions smaller than 2 nm-as a result of their rigid and contorted chain structures 30,31 .…”