Robotic Stepwise Synthesis of Hetero-Multinuclear Metal Oxo Clusters as Single-Molecule Magnets

High Resolution Image Download MS PowerPoint Slide An efficient stepwise synthesis method for discovering new heteromultinuclear metal clusters using a robotic workflow is developed where numerous reaction conditions for constructing heteromultinuclear metal oxo clusters in polyoxometalates (POMs) were explored using a custom-built automated platform. As a result, new nonanuclear tetrametallic oxo clusters {FeMn 4 }Lu 2 A 2 in TBA 5 [(A-α-SiW 9 O 34 ) 2 FeMn 4 O 2 {Lu(acac) 2 } 2 A 2 ] ( II A; A = Ag, Na, K; TBA = tetra- n -butylammonium; acac = acetylacetonate) were discovered by the installation of diamagnetic metal cations A + into a paramagnetic {FeMn 4 }Lu 2 unit in TBA 7 [(A-α-SiW 9 O 34 ) 2 FeMn 4 O 2 {Lu(acac) 2 } 2 ] ( I ). POMs II A exhibited single-molecule magnet properties with the higher energy barriers for magnetization reversal ( II Ag, 40.0 K; II Na, 40.3 K; II K, 26.7 K) compared with that of the parent I (19.7 K). Importantly, these clusters with unique properties were constructed as designed by a step of the predictable sequential multistep reactions with the time-efficient platform.