Q50 system

All chemicals were commercially purchased and were used without further purification. Powder X-ray diffraction (PXRD) patterns were recorded using a Bruker D8 ADVANCE X-ray powder diffractometer (Cu K_α, λ = 1.54184 Å). Thermogravimetric analyses (TGA) were performed using a TA Q50 system at a heating rate of 10 K min−¹ under a nitrogen atmosphere. Differential scanning calorimetry (DSC) measurements were performed by heating and cooling the powdered sample at a rate of 10 K min⁻¹ on a TA DSC Q2000 instrument. The dielectric measurements were carried out on a TH2838 impedance analyzer at frequencies from 5 kHz to 2.0 MHz, with an applied voltage of 1.0 V and a temperature sweeping rate of 3 K min⁻¹ approximately in the range of 100–440 K in a Mercury iTC cryogenic environment controller of Oxford Instrument. The pressed-powder pellets were fixed by two magnetic sheets acting as electrodes. Variable-temperature polarization microscopy observations were carried out on a polarizing microscope OLYMPUS BX41-P equipped with a Linkam cooling/heating stage THMSE 600. The temperature was stabilized to an accuracy of ±0.1 K. The SHG effect was measured using an XPL1064-200 instrument at a heating/cooling rate of 2 K min⁻¹.

Thermogravimetric measurements were performed by means of a Q50 system from TA Instruments (New Castle, DE, USA) under nitrogen flux from room temperature to 673 K. Heating rates of 10 K·min⁻¹ and sample masses of ca. 5 mg were used.

Reagents were commercially available and used without further purification except otherwise stated. The monomer 4-pyC₂H₃ was distilled to remove polymerization inhibitor hydroquinone before use. ESI-MS was obtained using a Shimadzu LCMS-2010A mass spectrometer, for which samples were digested by sonication in a mixture of hydrochloric acid and MeOH after removal of the residual monomers by sublimation under vacuum. Elemental analyses (EA) were conducted using an Elementar Vario EL analyzer using guest-free samples (with a little water adsorbed from air). IR spectra were recorded on a Bruker TENSOR 27 FT-IR spectrometer in the 400–4,000 cm⁻¹ region with KBr pellets. ¹H NMR and ¹³C NMR spectra were recorded on a Bruker AVANCE III 400 MHz NMR spectrometer. Chemical shifts were quoted in p.p.m. referenced to the appropriate solvent peak or 0.0 p.p.m. for tetramethylsilicane. PXRD patterns were collected on a Bruker D8-Advance diffractometer with Cu Kα radiation and a LynxEye detector. Thermogravimetry analyses were performed on a TA Q50 system under N₂ at a heating rate of 5 °C min. N₂ sorption isotherms were measured by a Micromeritics ASAP 2020M physisorption analyzer.