Rare-Earth Metal Alkyl, Amido, and Cyclopentadienyl Complexes Supported by Imidazolin-2-iminato Ligands: Synthesis, Structural Characterization, and Catalytic Application

Abstract

The rare earth metal dichlorides [(1)MCl(2)(THF)(3)] (2a, M = Sc; 2b, M = Y; 2c, M = Lu) and the gadolinium complex [(1)GdCl(2)(THF)(2)] x [LiCl(THF)(2)] (2d), containing the 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-iminato ligand 1, proved to be versatile starting materials for the preparation of trimethylsilylmethyl ("neosilyl") and bis(trimethylsilyl)amido complexes [(1)M(CH(2)SiMe(3))(2)(THF)(2)] (3a-3d) and [(1)M(HMDS)(2)(THF)] [4a-4d, HMDS = hexamethyldisilazide, N(SiMe(3))(2)] and for the preparation of the benzyl complex [(1)Lu(CH(2)Ph)(2)(THF)(2)] (5c) by the reaction with LiCH(2)SiMe(3), Na[N(SiMe(3))(2)], and KCH(2)Ph, respectively. Treatment of 2a-2c with KCp* afforded the mono(pentamethylcyclopentadienyl) complexes [(1)Sc(Cp*)Cl(THF)] (6a), [(1)Y(Cp*)Cl(THF)(2)] (6b), and [(1)Lu(Cp*)Cl(THF)] (6c). In contrast, the gadolinocene complex [(1)Gd(Cp*)(2)(THF)] (7) was isolated from the reaction of 2d with 2 equiv of KCp*. The molecular structures of 3a-3d, 4b.THF, 4d, 5c, 6a, 6c, and 7 x THF were determined by X-ray diffraction analyses, revealing the presence of exceptionally short metal-nitrogen bonds. The neosilyl complexes 3b and 3c showed high catalytic activity in the intramolecular hydroamination of aminoalkenes and aminoalkynes and in the hydrosilylation of 1-hexene and 1-octene with PhSiH(3).

Variable nuclearity scorpionate-supported lanthanide polyhydrides: [(TpR,R′)LnH2]n (n=3, 4 and 6)

“…It was also the pioneering work of Hou that showed that hydrogenolysis of the dialkyls leads to the corresponding dihydrides. Remarkably, the structure of these complexes proved to be based on novel, polynuclear cluster framework, such as tetranuclear [(C 5 Me 4 SiMe 3 )LnH 2 ] 4 (THF) 0e2 and hexanuclear [(C 5 Me 5 )LnH 2 ] 6 [13,14] and, equally notable was the unprecedented reactivity of these polyhydrides, for example toward nitriles [15a] and carbon monoxide [15b].…”

Highly Active and Diastereoselective N,O‐ and N,N‐Yttrium Complexes for Intramolecular Hydroamination

“…All aminoalkenes were distilled from CaH 2 under reduced pressure or under an argon atmosphere and stored in the glove box, for details see ref 10. Aminoalkenes 2,2‐diphenyl‐4‐pentenyl‐1‐amine ( 5 ),26 2‐methyl‐2‐phenyl‐4‐pentenyl‐1‐amine ( 7 ),7c 2,2‐diphenyl‐5‐hexenyl‐1‐amine ( 13 ),27 1‐methylpent‐4‐enylamine ( 15 ),28 2,2‐dimethyl‐4‐pentenyl‐1‐amine ( 9 ) and 2‐methyl‐4‐pentenyl‐1‐amine ( 11 )29 were prepared as described in the literature. The spectral data for the cis‐ and trans‐ isomers of 2,5‐dimethylpyrrolidine ( cis ‐ 16 and trans‐ 16 )28 were entirely consistent with those described in the literature.…”

“…Aminoalkenes 2,2‐diphenyl‐4‐pentenyl‐1‐amine ( 5 ),26 2‐methyl‐2‐phenyl‐4‐pentenyl‐1‐amine ( 7 ),7c 2,2‐diphenyl‐5‐hexenyl‐1‐amine ( 13 ),27 1‐methylpent‐4‐enylamine ( 15 ),28 2,2‐dimethyl‐4‐pentenyl‐1‐amine ( 9 ) and 2‐methyl‐4‐pentenyl‐1‐amine ( 11 )29 were prepared as described in the literature. The spectral data for the cis‐ and trans‐ isomers of 2,5‐dimethylpyrrolidine ( cis ‐ 16 and trans‐ 16 )28 were entirely consistent with those described in the literature. The diastereoselectivity for the cyclization of 15 to trans‐ 16 and cis ‐ 7f was determined based on 1 H NMR integration; trans ‐16 / cis ‐16 =3.14 (septet)/2.93 (m) for NCH peaks.…”

Selective Extraction of Scandium from Transition Metals by Synergistic Extraction with 2-Thenoyltrifluoroacetone and Tri-<i>n</i>-octylphosphine Oxide

“…REEs have attracted attention and aroused high interest in applying them in a variety of fields. Among them, the use of Sc has continuously increased in many application areas, such as scandium-aluminum alloys [1][2][3], where a Sc content of 2% by weight can make the alloys much stronger than other high-strength alloys, and minor amounts of high-purity Sc are used in semiconductors [4], specialty lighting [5,6], and catalysts [7,8]. Furthermore, new demands of Sc are expected to come from future fuel-cells [9,10], the aerospace industry and specialty metal alloys [2,3].…”