A Sacrificial Iminato Ligand in the Catalytic Cyanosilylation of Ketones Promoted by Organoactinide Complexes

Abstract

Four new complexes containing the bis­(pentamethylcyclopentadienyl)­thorium­(IV) moiety, Cp*2Th­(L1)­(Me) (Th2), Cp*2Th­(L2)­(Me) (Th3), Cp*2Th­(L1)Cl (Th5), and Cp*2Th­(L2)Cl (Th6), were synthesized in quantitative yields via the protonolysis reaction of the metallocene precursor complexes Cp*2Th­(Me)2 (Th1) and Cp*2Th­(Me)Cl (Th4) and the respective six- and seven-membered N-heterocyclic neutral imine ligands L1H and L2H. The molecular structures of all the complexes were established by single-crystal X-ray structure analyses. The synthesized complexes along with the precursor complexes were employed as catalysts for the cyanosilylation reaction of ketones with trimethylsilyl cyanide (Me3SiCN). The removal of the iminato ligand is necessary to trigger the reaction, allowing the formation of the active catalyst.

Base-free transfer hydrogenation of aldehydes and ketones catalyzed by imidazolin-2-iminato actinide complexes

“…5 The An-CH 3 (An = Th, U) distances are 2.502(4), 2.502(12), 2.436(4), and 1.865(13) Å for complexes 9-12, respectively, which are similar to those found for other actinide dimethyl and monomethyl metallocenes. 20 The formation of the mononuclear complexes was further confirmed by high-resolution mass spectrometric analysis. The major signal was observed at m/z 837.5752, 893.6217, 839.5560, and 900.7590 Da for complexes 9-12, respectively, corresponding to their molecular ions.…”

“…5 The An–CH 3 (An = Th, U) distances are 2.502(4), 2.502(12), 2.436(4), and 1.865(13) Å for complexes 9–12 , respectively, which are similar to those found for other actinide dimethyl and monomethyl metallocenes. 20…”

Catalytic regeneration of metal-hydrides from their corresponding metal-alkoxides via the hydroboration of carbonates to obtain methanol and diols

“…Three N -heterocyclic saturated neutral precursors of the iminato ligands L1-H , L2-H , and L3-H containing 5-, 6-, and 7-membered rings, respectively, with mesityl groups as wingtip substituents were synthesized following the literature-reported procedure. 17 The corresponding mono-iminato complexes of thorium, Th-2 , Th-3 , and Th-4 , were synthesized by the reaction of the corresponding neutral ligand and the thorium metallacycle [{(Me 3 Si)N} 2 Th{κ 2 -(C,N)-CH 2 SiMe 2 N(SiMe 3 )}], ( Th-1 ) in toluene (Scheme 2). The white crystalline synthesized complexes were fully characterized by various analytical techniques as well as single-crystal X-ray structure determination.…”

Metal–organic frameworks incorporating azobenzene-based ligands as a heterogeneous Lewis-acid catalyst for cyanosilylation of imines

“…Therefore, the catalytic cyanosilylation reactions were carried out at room temperature in DCM. In addition, it could be also found that the reaction yields were much lower without any catalyst or with the metal salts Zn(NO 3 ) 2 /CdCO 3 or the organic ligands H 4 abtc and azpy as the catalyst (entry [15][16][17][18][19], which indicated the catalytic activity of complexes 1 and 2 for the cyanosilylation of imines with TMSCN and the signicance of the formation of MOFs for the catalytic reactions.…”

“…In the past several decades, varieties of catalysts have been demonstrated to be efficient in this methodology but most of them are homogeneous, which leads to great difficulties in the separation and reusability of the catalysts. [10][11][12][13][14][15][16][17] In this regard, heterogeneous catalysts have caught researchers' attention because their inherent stability and ease of recovery make it simple but efficient to be separated and reused. [18][19][20][21][22][23][24] Therefore, it is of great signicance to develop well-performed heterogeneous catalysts for the synthesis of cyanohydrins.…”