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Synthesis, Characterization, and Magnetic Properties of Fe(BIP)3, a Novel Paramagnetic Relaxation Agent
Federico Vavassori1, Pietro Anzini1,2, Marco Lamperti1,2
1DiSAT-Department of Science and High Technology, Università degli Studi dell'Insubria, Via Valleggio 9-11, 22100 Como, Italy.
Pharmaceuticals (Basel, Switzerland)
|February 27, 2026
Summary
Researchers developed a novel iron(III) diketonate complex, Fe(BIP)3, which forms stable aggregates in water. These aggregates show potential as paramagnetic relaxation agents, offering an alternative to gadolinium-based contrast agents.
Area of Science:
- Coordination Chemistry
- Biomaterials Science
Background:
- Growing safety concerns regarding gadolinium-based contrast agents necessitate alternatives.
- First-row transition metal ions are emerging as viable replacements in coordination chemistry.
Purpose of the Study:
- To develop and characterize a novel homoleptic diketonate Fe(III) complex with indole moieties.
- To evaluate its potential as a paramagnetic relaxation agent by assessing its effect on water proton T1 and T2 relaxation times.
Main Methods:
- Synthesis and characterization of Iron(III) tris-1,3-(1-methylindol-3-yl)propanedionate [Fe(BIP)3] using thermal methods and spectroscopic techniques.
- Investigation of Fe(BIP)3 aggregation in aqueous solutions using dynamic light scattering and scanning electron microscopy.
- Evaluation of aggregate incorporation into phospholipid vesicles and assessment of paramagnetic properties (r1 and r2 relaxivities).
Main Results:
- Fe(BIP)3 was successfully synthesized and characterized.
- Aqueous Fe(BIP)3 solutions spontaneously formed nanoscale aggregates (≈30 nm hydrodynamic radius).
- Fe(BIP)3 aggregates exhibited longitudinal r1 relaxivity of 1.92 mM⁻¹s⁻¹ and transverse r2 relaxivity of 52.3 mM⁻¹s⁻¹.
Conclusions:
- Fe(BIP)3 aggregates, when stabilized within phospholipid vesicles, show significant promise as novel paramagnetic relaxation agents.
- This iron-based complex offers a potential alternative to gadolinium contrast agents in aqueous environments.
Keywords:
aggregationdynamic light scatteringfluorescence spectroscopyiron coordination complexesnuclear magnetic resonanceparamagnetic relaxation agentrelaxivityMore Related Videos
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