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Tetrahedral M(II) based binuclear double-stranded helicates: single-ion-magnet and fluorescence behaviour
Amit Kumar Mondal1, Vijay Singh Parmar, Soumava Biswas
1Department of Chemistry, IISER Bhopal, Bhopal 462066, MP, India. skonar@iiserb.ac.in.
Dalton Transactions (Cambridge, England : 2003)
|February 5, 2016
Summary
Rare dinuclear double-stranded helicates with tetrahedral cobalt(II) centers exhibit slow magnetic relaxation. These metal-organic frameworks also show fluorescence, offering dual functionality for advanced materials.
Area of Science:
- Coordination Chemistry
- Supramolecular Chemistry
- Materials Science
Background:
- Dinuclear double-stranded helicates are a rare class of supramolecular structures.
- Tetrahedral metal centers in such complexes are of interest for their magnetic and photophysical properties.
Purpose of the Study:
- To synthesize and characterize novel dinuclear double-stranded helicates with tetrahedral cobalt(II) and zinc(II) centers.
- To investigate the magnetic properties, specifically slow magnetic relaxation, of cobalt(II) helicates.
- To explore the fluorescence emission characteristics of zinc(II) helicates.
Main Methods:
- Synthesis of dinuclear double-stranded helicates using specific ligands (L(1) and L(2)).
- Characterization using elemental analysis and spectroscopic techniques.
- Magnetic susceptibility measurements (dc and ac) to study magnetic behavior.
- Fluorescence spectroscopy to determine quantum yields and lifetimes.
Main Results:
- Successful synthesis and characterization of four dinuclear double-stranded helicates: [Co2(L(1))2]·2(CH3CN) (1), [Co2(L(2))2]·6(CH3CN) (2), [Zn2(L(1))2]·2(CH3CN)·(CH3OH) (3), and [Zn2(L(2))2]·4(CH3CN) (4).
- Complexes 1 and 2 exhibit field-induced slow magnetic relaxation in high-spin tetrahedral Co(II) centers, indicative of easy-plane magnetic anisotropy.
- Complexes 3 and 4 display fluorescence emission in various solvents, with characterized quantum yields and lifetimes.
Conclusions:
- Dinuclear double-stranded helicates with tetrahedral metal centers can exhibit slow magnetic relaxation, a rare phenomenon for transition metal helicates.
- These helicates also possess tunable fluorescence properties, suggesting potential applications in both magnetism and luminescence.
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