The
continuous demand and uneven dispersal of natural mineral resources
of lithium with a low recycling rate of lithium commodities have forced
researchers to look for alternative resources like geothermal brine,
brackish brines, and sea brines. But selective
lithium-ion extraction and even lithium-ion binding from these aqueous
systems is a recognized challenge due to very high hydration energy
and the coexistence of other like metal ions but appealing due to
economic benefits. Therefore, the designed synthesis of synthetic
ionophores with high lithium selectivity is crucial as they can work
on dilute conditions without removal of interfering metal ions. However,
most of the lithium selective ionophores known in the literature are
mononucleated, and no emphasis is given on designing multinucleating
ionophore systems to improve the lithium loading capacity which will
open up unexplored paths toward the development of a more sustainable
and economical extraction process. Herein, we describe a rare fluorogenic
macrocyclic ionophore with two binding pockets for selective lithium
recognition and extraction among various major alkali and alkaline
earth metal ions of oceanic presence through both solid-state and
solution studies. Under solid-liquid extraction conditions, this receptor
shows a high lithium loading capacity of 135% with LiClO4 and 69.16% with LiCl salt with exclusive selectivity. Under liquid-liquid
extraction conditions, this ionophore shows a loading capacity of
27% with 1 M LiCl and 48.57% with 1 M LiClO4 source phase
concentration. This new ionophore, therefore, inspiring further to
modify and develop
a better multinucleating extractant with high lithium loading capacity
which is rare in the literature.