Synthesis of liquid crystalline poly(1 -pentyne)s and fabrication of polyacetylene-perovskite hybrids

Poly(l-pentyne)s containing biphenyl and phthalimido pendant groups with different spacer lengths {P1(m); -[HC=C(CH₂)₃O-Biph- OCO(CH₂)_mN(CO)₂C₆H₄] _n-, Biph=4,4'- biphenylyl; m = 7, 10} are synthesized in satisfactory yields by WCl₆-Ph₄Sn catalyst in toluene at elevated temperatures. The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, DSC, POM, and XRD analyses. Both of the polymers are thermally stable (T_d≥ 300 ° C) and exhibit nematicity at high temperatures. Their phthalimido groups are converted into amino groups by hydrolysis, which can, after acidification, complex with lead(II) bromide to furnish polyacetylene-perovskite hybrids in high yields. The organic components contribute good solubility to the hybrids, while the perovskite framework induces the polyacetylene chains to align within the inorganic sheets. The hybrids emit a strong UV light of 374 nm upon photo-excitation, whose quantum yield increases with an increase in the spacer length.