Uphill Anion Transporters with Ultrahigh Efficiency Based on <i>N</i> ‐Heterocyclic Carbene Metal Complexes

Essential to the function of living systems, transmembrane ion transport in nature has inspired synthetic mimics that advance therapeutics, separations, sensing, and bioelectronics. Here, we report highly efficient and selective anion transport mediated by simple N-heterocyclic carbene (NHC) organometallic compounds. Using ruthenium (Ru) as the central metal and ion binding site, we systematically investigated seven classes of organoruthenium scaffolds and found that NHC-based Ru complexes demonstrated exceptionally high activity and selectivity. Extending the study to more metals, NHC complexes of Pd, Ag, and Cu also exhibited remarkable transport efficiency, with the iPrPh-NHC organocopper compound achieving an EC₅₀ as low as 3.6 pM, surpassing one of the most active ion transporters, prodigiosin. Notably, NHC-based organometallic transporters leverage distinct kinetics of ligand binding and membrane diffusion to generate transmembrane potentials, and drive uphill ion transport reminiscent of proton pumps and ATPases. This work provides foundations for further development of organometallic ion transporters with high efficiency, tunable selectivity, and unique functions.