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Updated: Jan 11, 2026
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Author Spotlight: A Rapid, Microwave-Assisted Hydrothermal Synthesis Of Nickel Hydroxide Nanosheets
Published on: August 18, 2023
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Experimental Evidence for the Solid-State Nitrite-Ligand Photoisomerization Mechanism in Nickel(II) Square-Planar
Krystyna A Deresz1, Artem Mikhailov2, Joanna Jankowska1
1University of Warsaw, Faculty of Chemistry, Żwirki i Wigury 101, 02-089 Warsaw, Poland.
ACS Omega
|November 10, 2025
Summary
Researchers developed novel nickel(II) nitrite photoswitches, Ni-4d and Ni-4d', demonstrating light-induced conversion between nitro and nitrito isomers. The endo-nitrito isomer showed high stability and conversion efficiency in solid-state experiments.
Area of Science:
- Coordination Chemistry
- Photochemistry
- Materials Science
Background:
- Square-planar nickel(II) complexes are known for their diverse coordination geometries.
- Nitrite ligands can coordinate to metal centers in various modes, influencing complex properties.
- Photoswitchable molecules offer potential for light-controlled applications.
Purpose of the Study:
- To design and synthesize novel square-planar nickel(II) nitrite photoswitches.
- To investigate the light-induced isomerization of nitro to nitrito linkage isomers.
- To provide experimental evidence for theoretically predicted reaction mechanisms in the solid state.
Main Methods:
- Synthesis of Ni-4d and Ni-4d' complexes.
- Photocrystallography to determine crystal structures.
- Infrared (IR) spectroscopy to identify isomeric forms.
- Variable-temperature UV-Vis spectroscopy to study isomerization kinetics and stability.
Main Results:
- Successful synthesis of two square-planar nitrite nickel(II) photoswitches, Ni-4d and Ni-4d .
- Light-induced generation of both endo-nitrito and exo-nitrito linkage isomers using visible light (530 nm and 660 nm).
- High conversion to the endo-nitrito isomer (nearly 100%) and experimental confirmation of the nitro-to-endo-nitrito mechanism via the exo-nitrito intermediate.
Conclusions:
- The synthesized nickel(II) complexes function as effective photoswitches.
- The study provides the first experimental validation of a proposed nitro-to-endo-nitrito isomerization pathway in solid-state nickel(II) nitrite compounds.
- The stability of the endo-nitrito isomer was confirmed, with potential for light-controlled molecular devices.
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