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

Abstract

A nanoporous material bearing a high ion density and inherent organic radical character was synthesized by a facile one-pot process, which exhibits photo-, piezo- and chemochromism, driven by the diverse electron transfer processes between the acceptor framework and different electron donors.

Silanol-Enriched Viologen-Based Ionic Porous Hybrid Polymers for Efficient Catalytic CO2 Fixation into Cyclic Carbonates under Mild Conditions

“…The peak located at 401.4 eV originated from the N atoms of dicationic viologen moieties (V–N ++ ), the new emerging peak 400.5 eV may be assigned to the reduced radical cationic viologen species (V–N +• ) that formed during the reaction. , Further, the radical characters of V-iPHPs were confirmed by solid-state EPR spectroscopy. As shown in Figure I, both V-iPHP-1 and V-iPHP-2 exhibit EPR signals with g values of 2.004, which is due to a charge transfer from the aromatic core to the viologen moiety. − In recent years, viologen N radical species were found in other viologen-based POPs, ,− but the existence of these viologen N radical species has no obvious influence on the catalytic CO 2 fixation, ,, as also shown in this work. The Br 3d core-level spectra (Figure H) are fitted to Br 3d 3/2 and Br 3d 5/2 at 70.2/70.9 and 68.0/68.1 eV, which are assigned to free Br – anions within V-iPHPs.…”

Photo/Electrochromic Dual Responsive Behavior of a Cage-like Zr(IV)-Viologen Metal–Organic Polyhedron (MOP)

“…The peak at 533.34 eV showed relatively little shift to a higher binding energy compared with that of the native state (to 533.44 eV) (Figure d). Therefore, for the title compound, these changes confirmed the emergence of characteristic viologen radicals that were produced by the Cl → N and O → N electron transfers with Cl and O atoms acting as electron donors and N atoms of pyridinium as acceptors. ,,− …”

Quaternization-induced catalyst-free synthesis of viologen-linked ionic polyacetylenes towards heterogeneous catalytic CO2fixation

“…35,54 The N 1s spectra for VIPA-X (Fig. 2G) can be tted to three peaks: (i) the dominant peaks at higher BE values of 401.2 and 401.3 eV with very high tting area ratios (70% and 60%) are originated from N atoms of the dicationic viologen moieties (V-N ++ ) in VIPA-Br and VIPA-Cl; 23,25,29 (ii) small peaks at 399.9 and 400.1 eV with small tting area ratios (17% and 18%) should be assigned to some reduced viologen cationic radicals (V-N + c) that are in situ formed by the one-electron reduction of dicationic viologens during the thermal reaction; 23,25,29,36,55 (iii) other peaks with lower BE values of 398.4 and 398.5 eV with different tting area ratios (13% and 22%) belong to N atoms of unreacted bipyridines or some possible fully reduced neutral viologens (V-N). 23,35 The above results demonstrate that VIPA-X have high contents of viologen dicationic sites, small amounts of reduced viologen cationic radicals and neutral viologen species.…”

“…S6 †), showing typical organic radical signals with g values of 2.003. 23,55 In the XPS Br 3d spectrum (Fig. 2H) of VIPA-Br, two main divided peaks at 67.6 eV (Br 2p 3/2 ) and 66.6 eV (Br 2p 5/2 ) are assigned to free Br À anions, 16,35 while two affiliated peaks at 70.9 and 69.8 eV are assigned to the C-Br bond from the -CH 2 Br side groups in VIPA-Br.…”