Disentangling global and local ring currents.

Area of Science:

• Organic Chemistry
• Physical Chemistry
• Computational Chemistry

Background:

• Magnetic fields induce ring currents in aromatic and antiaromatic molecules, affecting NMR spectra.
• Analyzing (anti)aromaticity is challenging in polycyclic compounds with multiple ring current pathways.

Purpose of the Study:

• To develop a method for deconvoluting individual ring current contributions in polycyclic systems.
• To accurately quantify local and global ring current susceptibilities from experimental NMR data.

Main Methods:

• Application of the Biot-Savart law to NMR spectral analysis.
• Deconvolution of magnetic field-induced ring currents.
• Quantification of ring current susceptibilities.

Main Results:

• Accurate quantification of ring current susceptibilities in porphyrin nanorings and a bicyclic dithienothiophene-bridged [34]octaphyrin.
• Excellent agreement between experimental and computational chemical shifts.
• Validation against the GIMIC method for ring current calculations.

Conclusions:

• The Biot-Savart law-based method effectively deconvolutes complex ring currents in polycyclic molecules.
• This approach enables precise analysis of (anti)aromaticity using experimental NMR data.
• The method is broadly applicable to diverse polycyclic systems with available NMR data.