Dinuclear Iron(II) Triple Helicates Exhibiting Room Temperature Spin-Transition Behaviour in Solid and Solution Phase
Dibya Jyoti Mondal1, Arindam Gupta1, Sanjit Konar1
1Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal By-pass Road, Bhauri, Madhya Pradesh, 462066, India.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|April 27, 2023
Summary
Three new iron(II) helicates exhibit tunable spin-transition behavior. Ligand modifications fine-tune spin transitions in both solid and solution states, influenced by ligand field strength and crystal packing.
Area of Science:
- Coordination Chemistry
- Materials Science
- Supramolecular Chemistry
Background:
- Dinuclear iron(II) helicates are of interest for their unique spin-transition properties.
- Controlling spin-transition behavior is crucial for developing advanced materials.
Purpose of the Study:
- To synthesize novel dinuclear iron(II) helicates with fluorene-containing ligands.
- To investigate the effect of ligand field strength on spin-transition behavior in both solid and solution states.
Main Methods:
- Synthesis of three dinuclear iron(II) helicates with varying ligands.
- Characterization of spin-transition behavior using variable temperature 1H nuclear magnetic resonance (NMR) spectroscopy (Evans method) and UV-visible spectroscopy.
- Analysis of ligand field strength, crystal packing, and supramolecular interactions.
Main Results:
- Successful synthesis of three iron(II) helicates: [Fe2(L1)3](ClO4)4·2CH3OH·3H2O (1), [Fe2(L2)3](ClO4)4·6CH3CN (2), and [Fe2(L3)3](ClO4)4·0.5H2O (3).
- Observed a transition in spin-transition behavior from incomplete, multi-step to complete, around room temperature, modulated by ligand field strength.
- NMR and UV-visible spectroscopy confirmed spin transitions in solution, with transition temperatures (T1/2) following the order T1/2(1)
Conclusions:
- Ligand field strength, crystal packing, and supramolecular interactions effectively fine-tune the spin-transition behavior of iron(II) helicates.
- Terminal modulation of ligands provides a strategy for controlling spin-transition properties.
- The study highlights the intricate relationship between molecular structure and macroscopic material properties.
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