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Determination of the Photoisomerization Quantum Yield of a Hydrazone Photoswitch

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Published on: February 7, 2022

Conformational Control Governs Photoswitching Efficiency in Diazocines.

Shabana Butt¹, Piyush Kumar¹, Daniel Hugenbusch²

¹Department of Chemical Sciences, Indian Institute of Science, Education and Research, Mohali, Punjab, India.

Chemistry (Weinheim an Der Bergstrasse, Germany)

|April 11, 2026

Summary

This summary is machine-generated.

Diazocine derivatives exhibit distinct trans isomer conformations impacting photoswitching efficiency. Optimizing diazocine-based photoswitches requires avoiding the less efficient chair conformation in the trans state.

Keywords:

DFT computations conformations diazocine matrix isolation photoswitch

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Area of Science:

Photochemistry
Supramolecular Chemistry
Materials Science

Background:

Diazocines are promising photoswitchable molecules, outperforming traditional azobenzenes.
The trans isomer of diazocines can exist in multiple conformations, affecting their performance.
Understanding these conformations is crucial for designing efficient photoswitches.

Purpose of the Study:

To investigate the distinct conformations of diazocine trans isomers.
To determine how these conformations influence photoswitching efficiency.
To establish design principles for improved diazocine-based photoswitches.

Main Methods:

Matrix isolation spectroscopy at cryogenic temperatures (4 K) in solid argon and nitrogen.
Photochemical studies on parent diazocine, 2,9-diiododiazocine, and S-diazocine.
Combined experimental and computational explorations.

Main Results:

Two distinct trans isomer conformations, twist (E-t) and chair (E-c), were identified.
The twist conformation shows superior photoswitching behavior compared to the chair conformation.
S-diazocine exemplifies reduced performance when both conformations are similarly stable.

Conclusions:

A key structure-function relationship exists between diazocine conformation and photoswitching efficiency.
Cryogenic temperature observations provide valuable design parameters for room/physiological temperatures.
To maximize photoswitch performance, stabilization of the chair conformation in the trans state should be avoided.