A Cobotic, Digitally Controlled Schlenk-line Unlocks Access to Elusive Lewis-Base Stabilised Copper...

Silylamides are important ligands in coordination chemistry for their ability to stabilise low coordination numbers and provide soluble, and even volatile, metal complexes. Such compounds provide valuable insights into the fundamental bonding and reactivity of their respective metals. Despite the wealth of homo- and heteroleptic hexamethyldisilazide complexes of divalent 3d ions (Sc-Ni, Zn), attempts to access the corresponding divalent copper complexes have yielded only Cu(I) species. Herein, we demonstrate the stabilisation and isolation of a formally Cu(II) bis-hexamethyldisilazide which was achieved by implementing novel digital chemistry tools. In order to successfully isolate (DMAP)Cu^II(N{SiMe₃}₂)₂ (DMAP = N,N-dimethylaminopyridine), we investigated the roles of the co-ligand and silylamide transfer reagent in the kinetics of its formation. Crucial to these studies was our newly developed "cobotic" Schlenk line which provides digital control of the atmosphere under which we conduct our highly reactive syntheses. In digitising Schlenk-line handling, we have improved synthetic productivity by creating protocols for automated inertisation, solvent evaporation, liquid handling and crystallisation all while capturing reaction log data. Importantly, our Cu silylamide synthesis provides a case study showing that our cobotics approach allows for the discovery and isolation of unstable species which may remain elusive by traditional manual or fully autonomous methodologies.