Charge induced formation of crystalline network polymers

Abstract

Order in purely organic network polymers is hard to achieve, as reversible, dynamic covalent bond formation is required. Strategies have focused on thermodynamically controlled transformations, as kinetics would not seemingly favour reversibility. Herein, we report formation of crystalline network polymers under kinetically favoured conditions by using quaternary ammonium salt linked networks.Charged bulky bridges align, even under fast reaction times (20 minutes) if the rotational freedom is granted. Adding vicinal methyl substituents blocks the ordering, hence forming amorphous networks.Raman experiments and SEM images reveal stacking of 2D layers.

Facile synthesis of crystalline viologen-based porous ionic polymers with hydrogen-bonded water for efficient catalytic CO2 fixation under ambient conditions

“…The order crystallization is very rare in the reported viologen-based ionic polymers. 38,45 In detail, the sharp peak at 10.2 with a d-spacing value of 0.86 nm corresponds to molecular dimension of viologen moieties, which is in accordance with the molecular structure of 4,4 0 -BPy monomer ( Fig. S2 †).…”

“…As a result, the samples VIP-Cl (CH 3 CN) and VIP-Br (CH 3 CN) that synthesized in CH 3 CN have higher surface areas than samples prepared in other solvents, which would appear with the simplied names VIP-Cl and VIP-Br latter. To our knowledge, the prepared crystalline VIP-Cl possesses a relative high surface area of 56 m 2 g À1 , superior to most of viologen-based polymers with low surface areas that prepared by the Menshutkin reaction, 11,[45][46][47][48] comparable to viologen-based covalent organic networks that synthesized by the Zincke reaction, [38][39][40][41] but is still inferior to those viologenbased porous polymers that fabricated using various metal catalysts and additives [32][33][34][35] (see Table S1 † for the detailed comparisons). The morphology of VIP-X (X ¼ Cl or Br) was observed by the scanning electron microscopy (SEM) images.…”

“…11,53 Unfortunately, our attempts to provide the most probably structure for VIP-Cl materials have failed, because of the lack of enough available cell parameters obtained from XRD patterns, which are similar to previously reported ionic covalent organic polymers. 45 These situations mainly due to the reason that VIP-Cl materials are partially-crystalline linear polymers but not long-range order crystalline frameworks, which are different from typical crystalline framework materials such as metal-organic frameworks and covalent organic frameworks with denite topological structures and cell parameters. 24,25,29 Though the VIP-Cl samples obtained in different solvents have similar crystalline structures reected in the XRD patterns, their porous characters are obviously different, which were determined by N 2 adsorption/desorption measurements ( Fig.…”

“…22,23 In terms of synthesis, a series of viologen-based ionic polymers have been prepared using various strategies including C-C coupling reactions (e.g., Heck reaction, 32 and Sonogashira coupling reaction 33,34 ), ionothermal trimerization, 35 imine condensation, 36,37 Zincke reaction, [38][39][40][41] and Menshutkin reaction. 11,[42][43][44][45][46][47][48] Through coupling reactions and ionothermal reactions can afford viologen-based porous ionic polymers with high surface areas, these processes are complicated and environmental-unfriendly that require noble-metal catalysts or additives or high reaction temperatures. [32][33][34][35][36][37] Very recently, Zincke reaction has been used as a catalyst-free method to prepare viologen-based porous ionic networks with moderate surface areas.…”

Three birds, one stone – photo-/piezo-/chemochromism in one conjugated nanoporous ionic organic network

“…Herein, we report a built-in pyridinium chloride-based NION (termed NION-Cl) consisting of a triazine core and a 1,2-bis(4-pyridinium)ethylene (4,4′-bpe) branch. The electron-deficient pyridinium cation10 has been often used to construct functional organic or metal–organic hybrid materials 11. By integrating pyridinium cations into an organic aromatic skeleton, we observed enhanced photoelectrochemical redox activity, which in combination with the nanopores endows NION-Cl with reversible photo-, piezo- and chemochromism (the latter including solvo-, aniono- and vapochromism).…”