Tuning Antiaromaticity Through Meso‐Substituent Orientation in Core‐Modified Isophlorins DOI Creative Commons

Maika Isoda,

Haruna Sugimura, Yusuke Honda

et al.

Asian Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: May 22, 2025

Abstract Antiaromaticity is an essential principle in organic chemistry that significantly influences the properties of cyclic π‐conjugated systems. This study systematically investigated effects meso ‐substituents on antiaromaticity dithiadioxaisophlorins (S 2 O Iphs), which are stable isophlorin derivatives with strong antiaromatic characteristics. We synthesized two new S Iphs 3,5‐bis(trifluoromethyl)phenyl and 5‐cyanothien‐2‐yl substituents along a previously reported pentafluorophenyl‐substituted analog. Notably, derivative sterically demanding 2,6‐dichlorophenyl could not be isolated despite being detected by mass spectrometry, highlighting delicate balance between electronic stabilization, steric effects. Through comprehensive analysis using ¹H NMR spectroscopy, UV/vis absorption multiple computational approaches (NICS, GIMIC, HOMA/HOMAc, AV1245/AV min ), we demonstrate bulkiness predominantly determines their tilt angle relative to macrocycle, critically influencing antiaromaticity. Bulkier maintain larger angles, preserving stronger antiaromaticity, while less bulky groups allow greater π‐conjugation thereby reducing These findings provide valuable guidance for design functional materials tunable properties.

Language: Английский

Tuning Antiaromaticity Through Meso‐Substituent Orientation in Core‐Modified Isophlorins DOI Creative Commons

Maika Isoda,

Haruna Sugimura, Yusuke Honda

et al.

Asian Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: May 22, 2025

Abstract Antiaromaticity is an essential principle in organic chemistry that significantly influences the properties of cyclic π‐conjugated systems. This study systematically investigated effects meso ‐substituents on antiaromaticity dithiadioxaisophlorins (S 2 O Iphs), which are stable isophlorin derivatives with strong antiaromatic characteristics. We synthesized two new S Iphs 3,5‐bis(trifluoromethyl)phenyl and 5‐cyanothien‐2‐yl substituents along a previously reported pentafluorophenyl‐substituted analog. Notably, derivative sterically demanding 2,6‐dichlorophenyl could not be isolated despite being detected by mass spectrometry, highlighting delicate balance between electronic stabilization, steric effects. Through comprehensive analysis using ¹H NMR spectroscopy, UV/vis absorption multiple computational approaches (NICS, GIMIC, HOMA/HOMAc, AV1245/AV min ), we demonstrate bulkiness predominantly determines their tilt angle relative to macrocycle, critically influencing antiaromaticity. Bulkier maintain larger angles, preserving stronger antiaromaticity, while less bulky groups allow greater π‐conjugation thereby reducing These findings provide valuable guidance for design functional materials tunable properties.

Language: Английский

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