Poly(Pyridinium Salt)s Containing 2,7-Diamino-9,9′-Dioctylfluorene Moieties with Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline and Light-Emitting Properties

Abstract

A series of poly(pyridinium salt)s-fluorene main-chain ionic polymers with various organic counterions were synthesized by using ring-transmutation polymerization and metathesis reactions. Their chemical structures were characterized by Fourier Transform Infrared (FTIR), proton (1H), and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers. These polymers showed a number-average molecular weight (Mns) between 96.5 and 107.8 kg/mol and polydispersity index (PDI) in the range of 1.12–1.88. They exhibited fully-grown lyotropic phases in polar protic and aprotic solvents at different critical concentrations. Small-angle X-ray scattering for one polymer example indicates lyotropic structure formation for 60–80% solvent fraction. A lyotropic smectic phase contains 10 nm polymer platelets connected by tie molecules. The structure also incorporates a square packing motif within platelets. Thermal properties of polymers were affected by the size of counterions as determined by differential scanning calorimetry and thermogravimetric analysis measurements. Their ultraviolet-visible (UV-Vis) absorption spectra in different organic solvents were essentially identical, indicating that the closely spaced π-π* transitions occurred in their conjugated polymer structures. In contrast, the emission spectra of polymers exhibited a positive solvatochromism on changing the polarity of solvents. They emitted green lights in both polar and nonpolar organic solvents and showed blue light in the film-states, but their λem peaks were dependent on the size of the counterions. They formed aggregates in polar aprotic and protic solvents with the addition of water (v/v, 0%–90%), and their λem peaks were blue shifted.

Self‐assembly, mesomorphic behavior, and ionic conductivity of polymerized ionic liquid crystals with a threshold switching characteristic

“…Molecular weight properties including number‐average molecular weights ( M n ) and polydispersity index (PI) of the poly(pyridinium bromide)s were investigated by GPC, which are listed in Table 1. In order to suppress the ionic interaction between the polymer chains and the interaction with GPC column packing material, a small amount of LiBr (0.1 M) was employed to minimize the polyelectrolyte interaction between polymers 33 . For the poly(pyridinium bromide)s, the M n values were in the range of 54.9–58.2 kg mol −1 , and the PI values were between 1.37 and 1.74, indicating good polydispersity.…”

“…In order to suppress the ionic interaction between the polymer chains and the interaction with GPC column packing material, a small amount of LiBr (0.1 M) was employed to minimize the polyelectrolyte interaction between polymers. 33 For the poly(pyridinium bromide)s, the M n values were in the range of 54.9-58.2 kg mol À1 , and the PI values were between 1.37 and 1.74, indicating good polydispersity.…”

Synthesis of Azonia Aromatic Heterocycles Bearing 6–6–6–5–6 Pentacyclic Core via Intramolecular [4 + 2]-Cycloaddition and Oxidative Aromatization Reaction Sequence in One Pot

“…2-Bromo-14-cyano-7-phenyl-6H-benzo [4,5]thiazolo [3,2-a]chromeno [4,3-d]pyridin-8-ium (5b). Pale yellow solid, 73.6 mg (66% yield); R f = 0.20 (9:1 DCE/MeOH); compound 5b was purified by silica gel column chromatography using a gradient mixture of 0 → 5% MeOH in DCE as an eluent; 4, 157.1, 147.2, 140.9, 139.6, 138.6, 132.9, 130.8, 130.4, 129.7, 128.9, 128.7, 128.6, 127.2, 125.5, 121.1, 119.5, 118.9, 115.0, 114.3, 100.9, 64.6; 19 2-Bromo-14-cyano-7-(naphthalen-1-yl)-6H-benzo [4,5]thiazolo- [3,2-a]chromeno [4,3-d]pyridin-8-ium Tetrafluoroborate (5c).…”

“…2-Bromo-14-cyano-7-phenyl-6H-benzo [4,5]thiazolo [3,2-a]chromeno [4,3-d]pyridin-8-ium (5b). Pale yellow solid, 73.6 mg (66% yield); R f = 0.20 (9:1 DCE/MeOH); compound 5b was purified by silica gel column chromatography using a gradient mixture of 0 → 5% MeOH in DCE as an eluent; 4, 157.1, 147.2, 140.9, 139.6, 138.6, 132.9, 130.8, 130.4, 129.7, 128.9, 128.7, 128.6, 127.2, 125.5, 121.1, 119.5, 118.9, 115.0, 114.3, 100.9, 64.6; 19 2-Bromo-14-cyano-7-(naphthalen-1-yl)-6H-benzo [4,5]thiazolo- [3,2-a]chromeno [4,3-d]pyridin-8-ium Tetrafluoroborate (5c). Pale yellow solid, 72.8 mg (60% yield); R f = 0.20 (9:1 DCE/MeOH); compound 5c was purified by silica gel column chromatography using a gradient mixture of 0 → 5% MeOH in DCE as an eluent; 4, 157.2, 145.7, 141.0, 139.6, 138.1, 133.4, 130.4, 129.6, 129.5, 129.4, 129.0, 128.9, 128.7, 128.6, 128.2, 128.1, 126.5, 125.5, 125.5, 123.8, 121.1, 118.9, 118.8, 115.0, 114.4, 101.4, 64.5; HRMS (ESI-TOF) calculated for C 29 H 16 BrN 2 OS [M-BF 4 ] + : 519.0161 found 519.0165.…”

“…4 They are also considered as potential candidates for organic light-emitting diodes (OLEDs). 5 Owing to these wide range of applications, the development of new methods for the synthesis of cationic N-heterocycles has gained significant traction in recent years. Notable methods for the synthesis of N-heterocycle-fused cationic organic compounds are ring-closing metathesis (Scheme 1a), 6 Rh-catalyzed C−H activation (Scheme 1b), 7 Pd-catalyzed C− H activation (Scheme 1c), 8 Au-catalyzed cyclization (Scheme 1d), 9 Cu-mediated C−H activation−cyclization (Scheme 1e), 10 intramolecular radical arylation, 11 and oxidative photocyclization, 12 among others.…”