Volume 62, Issue 29 e202301124
Research Article

Manipulating Electron-Transfer Events in [Fe4Co4] Cubes via a Mixed-Ligand Approach: The Impact of Elastic Frustration

Zi-Yi Chen

Zi-Yi Chen

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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Qi Liu

Qi Liu

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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Yue Cheng

Yue Cheng

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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Yi-Fei Deng

Yi-Fei Deng

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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Shihao Liu

Shihao Liu

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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Xin-Yi Wang

Corresponding Author

Xin-Yi Wang

State Key Laboratory of Coordination Chemistry, Collaborative Innovation Center of Advanced Microstructures, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023 China

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Yuan-Zhu Zhang

Corresponding Author

Yuan-Zhu Zhang

Department of Chemistry, Southern University of Science and Technology (SUSTech), Shenzhen, 518055 China

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First published: 20 May 2023
Citations: 6

Graphical Abstract

Two cyanide-bridged [Fe4Co4] cubes were prepared via a mixed-ligand approach. The molecular origins of their distinct (incomplete vs. complete) metal-to-metal electron transfer (MMET) properties were identified as the presence and absence of the inter-cluster alkynyl-alkynyl and CH/π interactions. These compete with the cluster-anion interactions, resulting in the underlying elastic frustration and stopping the complete spin transition in 1.

Abstract

The engineering of intermolecular interaction is challenging but critical for magnetically switchable molecules. Here, we prepared two cyanide-bridged [Fe4Co4] cube complexes via the alkynyl- and alcohol-functionalized trispyrazoyl capping ligands. The alkynyl-functionalized complex 1 exhibited a thermally-induced incomplete metal-to-metal electron transfer (MMET) behaviour at around 220 K, while the mixed alkynyl/alcohol-functionalized cube of 2 showed a complete and abrupt MMET behaviour at 232 K. Remarkably, both compounds showed a long-lived photo-induced metastable state up to 200 K. The crystallographic study demonstrated that the incomplete transition of 1 was likely due to the possible elastic frustration originating from the competition between the anion-propagated elastic interactions and inter-cluster alkynyl-alkynyl & CH-alkynyl interactions, whereas the latter are eliminated in 2 as a result of the partial substitution by the alcohol-functionalized ligand. Additionally, the introduction of chemically distinguishable cobalt centers within the cube unit of 2 did not lead to a two-step but a one-step transition, possibly because of the strong ferroelastic intramolecular interaction through the cyanide bridges.

Conflict of interest

The authors declare no conflict of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.

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