Uranium extraction from seawater is a promising strategy to secure sustainable nuclear fuel resources, yet it faces major 

challenges due to the extremely low uranium concentration (≈3.3 ppb), high ionic strength, and strong stability of the 

uranyl-tricarbonate complex [UO2(CO3)3]

4−. This review summarizes recent advances in ligand design for selective uranyl 

(UO2

2+) capture, emphasizing the correlation between electronic structure, coordination geometry, and extraction performance.

Quantum-chemical and spectroscopic studies have established that the η2

(N, O) coordination mode in amidoxime

(AO) ligands forms mixed σ–π hybrid covalent bonds with uranyl 5f/6d orbitals, weakening axial U=O bonds and 

strengthening equatorial interactions. Rational molecular strategies include (i) electron-density modulation, (ii) internal 

hydrogen bonding for geometric fixation, (iii) proton-relay-assisted carbonate dissociation, and (iv) N-alkylation for U/V 

selectivity. Beyond AO, ligands such as Saldian (N3O2) and phenanthroline dicarboxylates employ rigid π frameworks 

and cooperative chelation to achieve high stability (log β≈28), while biomolecule-derived systems like SUP proteins and 

DNA hydrogels exhibit femtomolar uranyl affinity. Six design parameters—including electron-density tuning, internal 

hydrogen bonding, proton-relay activation, coordination directionality, π-resonance control, and surface optimization—

now define a predictive paradigm for uranyl–ligand coordination. The integration of density-functional theory, advanced 

spectroscopy, and machine-learning-driven inverse design enables rapid identification of high-affinity, seawater-resilient 

ligands and guides the creation of electronically tuned materials for next-generation, durable, and sustainable uraniumextraction

technologies.