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Updated: Jan 18, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
One-Step Radical α-α Coupling Accesses Helical Near-Infrared 3-Pyrrolyl Boron Dipyrromethene Dimers
Debendra Tewary1,2, Abani Sarkar1, David R Turner2
1Department of Chemistry, Indian Institute of Techology Bombay, Powai, Mumbai 400076, India.
Abstract:
The direct α-α coupling of 3-pyrrolyl boron dipyrromethenes (BODIPYs) affords helical near-infrared (NIR)-active dimers in one step via a radical Pd-catalyzed process. X-ray analysis reveals Z-type helical packing stabilized by π-π stacking and hydrogen-bonding interactions. These dimers showed pronounced bathochromic absorption shifts compared to monomers and solvent-dependent charge-transfer bands up to 905 nm with fluorescence quenching. Density functional theory and time-dependent density functional theory studies confirmed the excited-state behavior, highlighting a concise route to structurally unique NIR photofunctional BODIPY assemblies.
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