Four-Membered Lutetaheterocycles

Abstract

The four-membered metallacyclic lutetium complexes Tp tBu,MeLu­[CH2(SiMe2)­NR] were synthesized via protonolysis of Tp tBu,MeLuMe2 (Tp tBu,Me = hydrotris­(3-methyl-5-tert-butylpyrazolyl)­borato) with silylamines HN­(SiMe3)­R (R = SiMe3, C6H3(CF3)2-3,5 (ArCF3)). The sterically less demanding amine HN­(SiHMe2)2 led to the isolation of the heteroleptic complex Tp tBu,MeLuMe­[N­(SiHMe2)2]. The accessibility of the complex Tp tBu,MeLu­[CH2(SiMe2)­NArCF3] to intramolecular ring opening was explored using HOCH2 tBu, affording lutetium neopentoxide complexes Tp tBu,MeLu­[N­(SiMe3)­ArCF3]­(OCH2 tBu) and Tp tBu,MeLu­(OCH2 tBu)2. Treatment of Tp tBu,MeLu­[CH2(SiMe2)­NArCF3] with H3SiPh resulted in an unusual ring hydrogen/silyl group exchange and formation of Tp tBu,MeLu­[CH­(SiH2Ph)­(SiMe2)­NArCF3], retaining the four-membered lutetaheterocycle. All complexes were fully characterized by NMR/IR spectroscopy, elemental analysis, and X-ray crystallography.

Lanthanide Amide Complexes Supported by the Bis‐tris(pyrazolyl)borate Ligand Environment

“…[28] The LnÀ N(N'') distances in 2-Ln (Ln = Y, Dy) are longer than those in 2-Yb (2.2956(12) Å), and consistent with differences in size of the different Ln(III) ionic radii. [15,29] The LnÀ N(NHAr CF3 ) distances of 2.3069 (12) Å in 3-Y and 2.3019(18) Å in 3-Dy are consistent with each other and as expected shorter than those in 2-Ln. [15] The LnÀ N(amido) distances of 2-Ln and 3-Ln are comparable to but shorter than the NdÀ N(NPh 2 ) bond of 2.480(5) Å in [Nd(Tp*) 2 (NPh 2 )].…”

“…[10] Lanthanide [bis(silyl)]amide Ln(II) complexes with one Tp R ancillary ligand, [Ln(Tp tBu,Me )(N'')] (Ln = Sm, Tm, Yb; Tp tBu,Me = hydrotris(3-t Bu-5-methyl-1-pyrazolyl)borate) [11] and the Lu(III) complex [Lu(Tp tBu,Me )(N(SiHMe 2 ) 2 )(CH 3 )] have been reported. [12] However, with two Tp R ancillary ligands, the synthesis of such secondary lanthanide amides becomes challenging due to the steric bulk of two Tp R ligands. Metathesis of the Ln(III) complexes [Ln(Tp*)(Cl) 2 ] (Ln = Y, Er; Tp* = hydrotris(3,5-dimethyl-1-pyrazolyl)borate) with K(N'') proved unsuccessful.…”

“…Substituted analogues of Trofimenko's scorpionate tris(1‐pyrazolyl)borate (Tp R ) ligand provide a robust ancillary ligand environment for the synthesis of reactive lanthanide complexes [10] . Lanthanide [ bis (silyl)]amide Ln(II) complexes with one Tp R ancillary ligand, [Ln(Tp t Bu,Me )(N′′)] (Ln=Sm, Tm, Yb; Tp t Bu,Me =hydrotris(3‐ t Bu‐5‐methyl‐1‐pyrazolyl)borate) [11] and the Lu(III) complex [Lu(Tp t Bu,Me )(N(SiHMe 2 ) 2 )(CH 3 )] have been reported [12] . However, with two Tp R ancillary ligands, the synthesis of such secondary lanthanide amides becomes challenging due to the steric bulk of two Tp R ligands.…”