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Updated: May 24, 2025

Spatial Separation of Molecular Conformers and Clusters
Published on: January 9, 2014
5,5'-Biindeno[2,1-c]fluorene: importance of C5-C5' linkage for an indeno[2,1-c]fluorene dimer exhibiting an
Neha Maurya1, Palash Jana2, Himanshu Sharma1
1Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India. chmsdas@iitrpr.ac.in.
Abstract:
Mesityl-protected indeno[2,1-c]fluorene and its C2-C2'-linked dimer 2,2'-biindeno[2,1-c]fluorene are closed-shell molecules. Herein, we report the synthesis and characterization of a mesityl-protected 5,5'-biindeno[2,1-c]fluorene displaying 26.4% diradical and 0.9% tetraradical characters. The C5-C5' linkage between two [2,1-c]IFs is crucial for its open-shell character, resulting in its far-red UV-vis absorption, redox amphoterism, partially para-quinoidal as-indacene core, and temperature-dependent EPR response due to a small singlet-triplet energy gap.
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