Comparison of group 4 and thorium M(iv) substituted cyclopentadienyl silanide complexes

Abstract

We report the synthesis and characterisation of a series of M(IV) substituted cyclopentadienyl hypersilanide complexes of the general formula [M(CpR)2{Si(SiMe3)3}(X)] (M = Hf, Th; CpR = Cp′, {C5H4(SiMe3)} or Cp′′,...

Covalency-Driven Differences in the Hydrogenation Chemistry of Lanthanide- and Actinide-Based Frustrated Lewis Pairs

“…The other example comes from Driess and co-workers, who demonstrated the hydrogenation of a silylene/borane intramolecular FLP . The elusiveness of such reactions is typically attributed to the large singlet–triplet gap in cyclic silylenes and particularly those with strong heteroatom donors such as nitrogen. − Hence, the direct hydrogenation of free silylenes is reserved for acyclic silylenes lacking resonance and strong π-donors. ,, The FLP-type hydrogenation of the cyclic alkyl silylene C 4 H 4 (SiMe 3 ) 4 Si has been achieved using silylium, phosphine, amine, and borane counterparts, although the mechanisms of these reactions remain open. , Second, although the number of organoactinide–silicon bonds continues to grow, − reports of new reactivity with these species are very scarce despite the weak, polar nature of these bonds. , Older reports demonstrated the isocyanide and CO insertion chemistry of An–Si bonds, as well as their susceptibility to protonolysis. − The reactivity of organolanthanide–silicon species has been studied more extensively, including recently by P. Roesky and co-workers. − Finally, while complex 5-U is an isolable Lewis adduct that shows some evidence for bonding in solution, we have not been successful in attempts to isolate adducts of 2 and 3-La or 3-Nd . The hydrogenation reactions utilizing these pairs appear to be termolecular at face value.…”

N-Aryloxide-Amidinate Thorium Complexes

“…Our group has been dedicated to developing novel ligands for small molecule activation. − Recently, we have designed and synthesized an N -aryloxide-amidine ligand ( 1 ), [ONNO] ligand, connecting phenoxide (PhO – ) ligands with amidine and alkyl (CH 2 ) linkers. , This work led to the synthesis of distinctive organometallic complexes with group 4 metals, where the [ONNO] ligand featured flexibility in coordination. Given the diverse coordination potential of amidine ligands − and the similarities between hafnium and thorium, ,,− we are now exploring the application of our N -aryloxide-amidine ligand in thorium chemistry.…”