Cascade Polyannulation of Diyne and Benzoylacetonitrile: A New Strategy for Synthesizing Functional Substituted Poly(naphthopyran)s

Abstract

A new strategy for synthesizing multisubstituted poly-(naphthopyran)s (PNPs) with novel functionalities was described. The cascade oxidative polyannulation of benzoylacetonitrile and internal diynes are catalyzed by [RhCp*Cl 2 ] 2 and Cu(II) acetate in dimethylformamide at 90°C, generating PNPs with high molecular weight of up to 19 300 in excellent yields (isolation yield up to 96.4%). This polymerization method enjoys the remarkable advantages of high reaction rate, high efficiency, and atom-economy. All of the polymers show good solubility in common organic solvents and high thermal stability (degradation temperature up to 431°C). The thin films of PNPs display high refractive indices (1.5137−1.7524) in a wide wavelength range of 450−1600 nm. PNP containing tetraphenylethene units can be utilized to generate a well-resolved nanoscale photopattern by UV irradiation of its film through a copper mask. The PNPs exhibit the phenomena of mechanochromism and vapochromism: their emission is turned on upon scratching and solvent fuming their solid powders. Such attributes allow the polymers to be used as security materials or fluorescent indicators in various fields.

The Marriage of Aggregation‐Induced Emission with Polymer Science

“…Thus, they can be fabricated into large‐area thin films, fibers, and components with different shapes by simple and energy‐saving techniques . If we marry AIEgens with polymer materials via chemical synthesis or physical blending strategy, the obtained AIE polymeric systems would inherit the merits from both sides to show great potential in various high‐tech applications, such as sensitive and selective fluorescent chemosensors, efficient emitters in organic light‐emitting diodes, multi‐responsive materials, photopatterning, and biological imaging …”

Mechanochromic Fluorescent Polymers Enabled by AIE Processes

“…Besides the physical doping strategy, mechanochromic fluorescent polymers can also be obtained by chemically linking AIEgens into polymer chains. [ 29 ] The chemical strategy can endow mechanochromic fluorescent polymers with additional advantages over the physical strategy. For instance, the dye/polymer compatibility and the dispersion uniformity of AIEgens can be radically improved by chemically introducing AIEgens in polymer structures.…”

Transition Metal‐Catalyzed Intermolecular Cascade C−H Activation/Annulation Processes for the Synthesis of Polycycles

“…Subsequently, this intermediate reacts with the alkyne by cleavage of the O−H/C(sp 2 )−H bonds, affording the final product. Then this method was employed to synthesize multi‐substituted poly‐(naphthopyran)s with novel functionalities by Tang and co‐workers [38] …”

“…Then this methodw as employed to synthesize multi-substituted poly-(naphthopyran)s with novel functionalities by Ta ng andc o-workers. [38] Along the line, Liu and co-workers later extended this strategy to diazo compounds by using NaOAc as additive at room temperature (Scheme 16). [39] Diversified substituted benzo[de]chromenes were synthesized via Rh III -catalyzed double CÀHa ctivation and annulation, showing high functional-group tolerance.…”