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Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
From low to very high birefringence in bis(2-pyridylimino)isoindolines: synthesis and structure-property analysis
Edwin W Y Wong1, Jeffrey S Ovens, Daniel B Leznoff
1Department of Chemistry, Simon Fraser University, Burnaby, BC, V5A 1S6 Canada.
Abstract:
A series of new substituted 1,3-bis(2-pyridylimino)isoindolines--1,3-bis(2-pyridylimino)-5,6-bis(2,6-diisopropylphenoxy)isoindoline (2b), 1,3-bis(2-pyridylimino)-5,6-bis(4-tert-butylphenyl)isoindoline (2c), and 1,3-bis(2-pyridylimino)-5-tert-butylisoindoline (2d)--were synthesized and structurally characterized by single-crystal X-ray diffraction. The birefringence (Δn) of the crystals of unsubstituted 1,3-bis(2-pyridylimino)isoindoline (2a), 2b, 2c, and 2d were measured and found to vary greatly, with Δn values of 0.0654(3), 0.0629(17), 0.588(10), 0.701(12), respectively. A structure-property relationship for the birefringence values of 2a-2d was outlined and indicated that the anisotropy of the polarizability of the molecules plays a crucial role in the birefringence of the crystals. The greatest birefringence values are achieved when the molecules are oriented in a face-to-face configuration intermolecularly, and along the crystallographic face being measured.
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