Lewis Base Supported Terminal Thorium Imido Metallocene [η5-1,3-(Me3C)2C5H3]2Th(═Ndipp)(dmap): Its Synthesis, Structure, and Reactivity

Abstract

Addition of dippNH₂ (dipp = 2,6-ⁱPr₂Ph) to a toluene solution of thorium dimethyl metallocene (Cp^2tBu)₂ThMe₂ (1; Cp^2tBu = η⁵-1,3-(Me₃C)₂C₅H₃) in the presence of 4-dimethylaminopyridine (dmap) affords the Lewis base supported terminal thorium imido metallocene, (Cp^2tBu)₂Th(═Ndipp)(dmap) (3), concomitant with methane release. Complex 3 acts as a synthon for the (Cp^2tBu)₂Th(II) fragment when exposed to Ph₂E₂ (E = S, Se). Moreover, it activates conjugated alkynes, ketones, thio-ketones, CS₂, isothiocyanates, seleno-ketones, esters, diazabutadienes, carbodiimides, organic azides, and chlorosilanes, resulting in pyridyl alkenyl complexes, dimeric oxido, sulfido, and selenido complexes, alkoxido amidate, (hetero)metallacycle, bis-amido, and dichloride complexes, respectively. Furthermore, it engages in deprotonation reactions with thiazole, terminal alkyne, ketones, amidate, imine, nitriles, and isonitriles, forming the amido thiazolyl complex, bis-alkynyl complexes, amido enolyl complexes, bis-amidates, amido-iminato complexes, amido pyridyl complexes, iminato complexes, and bis-amido complexes, respectively. In addition, it undergoes a Cannizarro-type reaction with aromatic aldehydes or Friedel–Crafts alkylation with Ph₃CN₃, respectively. Lastly, it forms a heterobimetallic complex (Cp^2tBu)₂Th(Cl)[N(dipp)Cu(dmap)] (34) in the presence of CuCl. Furthermore, substituent effects on the cyclopentadienyl and imido ligands that modulate the reactivity have been further probed.