Novel bipyrazolo[1,5-a]pyridine luminogens with aggregation-induced emission enhancement properties

Abstract

7,7′-Diaryl-3,3′-bipyrazolo[1,5-a]pyridines luminogens display aggregation-induced emission enhancement properties, showing potential applications in the field of organic luminescent materials.

Synthesis and Mechanistic Investigation of Bipyrazolo[1,5-a]pyridines via Palladium-Catalyzed Cross-Dehydrogenative Coupling of Pyrazolo[1,5-a]pyridines

“…Optimization for Synthesis of 7,7′-Siaryl-3,3′bipyrazolo[1,5-a]pyridine 2. Since the serendipitous discovery of the homo-coupled 3,3′-bipyrazolo[1,5-a]-pyridine product, 14 numerous efforts in our laboratories have been made to optimize the synthesis of 7,7′-diaryl-3,3′-bipyrazolo-[1,5-a]pyridine 2 from the 7-arylpyrazolo[1,5-a]pyridine 1 monomer via palladium(II)-catalyzed C−H/C−H cross coupling. See the Supporting Information (SI) for the preparation of substrate 1.…”

“…In 2016, one of us successfully developed a palladium-catalyzed direct C–H bond arylation methodology that facilitates the functionalization of the parental pyrazolo­[1,5- a ]­pyridine substrate at the C(3)- and C(7)-positions. More recently, triggered by the serendipitous discovery of a homo-coupled product, we reported the aggregation-induced emission enhancement (AIEE) properties of a series of 7,7′-diaryl-3,3′-bipyrazolo­[1,5- a ]­pyridines, which show promise as organic luminescent materials into the bargain.…”

Direct C7‐H Arylation of Pyrazolo[1,5‐a]azines with Aryl Chlorides

“…The palladium-catalyzed direct C7-H arylation of pyrazolo [1,5a]azines is a unified strategy for the synthesis of well-known and important bi(hetero)aryl structural motifs in organic chemistry; and therefore, becomes an attractive target for the development of new synthetic methods (Scheme 1A, left). [1][2][3][4][5] Selected examples highlighting the importance of 7-(hetero)aryl pyrazolo [1,5-a]azines in drugs and organic materials include the sedative agent Indiplon (I), [6] MRP1 inhibitor Reversan (II), [7] CFTR activator Cact-3 (III), [8] CRF 1 antagonist (IV), [9] 5-HT 4 R partial agonist (V), [10] and dimeric organic luminescent materials (VI) [11] (Scheme 1B).…”

Bisphosphonium salt catalyzed [3 + 2] annulation of N-tosylimino(iso)quinolinium ylides with aryl olefins under blue LED irradiation

“…1). [4][5][6][7][8][9][10] Increasing and tremendous attention has been devoted to the synthesis of pyrazolo(iso)quinolines in the past decades. Initially, the pyrazolo(iso)quinoline compounds were synthesized in medium yields through [3 + 2] cycloaddition reactions of N-imino(iso)quinolinium ylides with electrondeficient alkynes.…”