Yttrium complexes incorporating the chelating diamides {ArN(CH₂)_xNAr}²⁻(Ar = C₆H₃-2,6-ⁱPr₂, x = 2, 3) and their unusual reaction with phenylsilane

Abstract

Novel yttrium chelating diamide complexes [(Y[ArN(CH(2))(x)NAr](Z)(THF)(n))(y)] (Z = I, CH(SiMe(3))(2), CH(2)Ph, H, N(SiMe(3))(2), OC(6)H(3)-2,6-(t)Bu(2)-4-Me; x = 2, 3; n = 1 or 2; y = 1 or 2) were made via salt metathesis of the potassium diamides (x = 3 (3), x = 2 (4)) and yttrium triiodide in THF (5,10), followed by salt metathesis with the appropriate potassium salt (6-9, 11-13, 15) and further reaction with molecular hydrogen (14). 6 and 11(Z = CH(SiMe(3))(2), x = 2, 3) underwent unprecedented exchange of yttrium for silicon on reaction with phenylsilane to yield (Si[ArN(CH(2))(x)NAr]PhH) (x = 2 (16), 3) and (Si[CH(SiMe(3))(2)]PhH(2)).

Postmetallocene Lanthanide–Hydrido Chemistry: A New Family of Complexes [{Ln{(Me3Si)2NC(NiPr)2}2(μ‐H)}2] (Ln=Y, Nd, Sm, Gd, Yb) Supported by Guanidinate Ligands—Synthesis, Structure, and Catalytic Activity in Olefin Polymerization

“…In contrast to the welldeveloped chemistry of cyclopentadienyl-derived hydrido complexes of lanthanides, their analogues in alternative coordination environments still remain extremely poorly investigated. [20][21][22][23][24][25][26][27] Recently, research activity has been directed to design new ligand sets to extend the means of modification and control of reactivity of complexes. In an attempt to increase the electrophilicity of the metal center many research groups have focused their work on "harder" polydentate N and/or O coordinating ligands.…”

Methylaluminum‐Supported Rare‐Earth‐Metal Dihydrides

“…[6] Several types of ancillary ligands have been employed in an effort to stabilize complexes of low nuclearity, including sterically demanding cyclopentadienyl derivatives such as C 5 Me 4 SiMe 3[6] tris(pyrazolyl)borato scorpionates, [7] tetraazacycloamido, [8] bis(phosphinophenyl)amido pincer, [5] and pyridylamido [9] ligands as well as chelating diamido ligands (see Supporting Information). [10] However, the synthesis of a monomeric rare-earth-metal dihydride was not successful to date.The group of Takats used the sterically demanding hydrotris(3-tert-butyl-5-methylpyrazolyl)borato ligand (Tp tBu,Me ) to stabilize Ln 2+ centers in species such as alkyls, [11] carbenes, [12] amides, [11b] halides, [11,13] or hydrides [14] and was also able to obtain lanthanide dihydride complexes using the less-bulky dimethyl, diisopropyl, or unsubstituted derivative of the Tp ligand, but reported the formation of a mixture of products for the more bulky Tp tBu,Me ligand because of possible side reactions involving the ligand tertbutyl group. [7,15] Since tetrameric [(Tp R LnH 2 ) 4 ] as well as the other dihydride clusters reported were all synthesized from alkyl precursors by the addition of H 2 or silanes, we tried to adopt a different route using HAlMe 2 as hydride source.…”

“…[6] tris(pyrazolyl)borato scorpionates, [7] tetraazacycloamido, [8] bis(phosphinophenyl)amido pincer, [5] and pyridylamido [9] ligands as well as chelating diamido ligands (see Supporting Information). [10] However, the synthesis of a monomeric rare-earth-metal dihydride was not successful to date.…”

Molecular Rare‐Earth‐Metal Hydrides in Non‐Cyclopentadienyl Environments

“…It consists of a trinuclear metal core bridged by five hydrido ligands, in a manner similar to that shown previously. [35,36] Presumably, one hydrido ligand was lost through dehydrogenative metalation of the unsaturated backbone of a pyrazole moiety of one of the NNN pincer ligands (Scheme 17).…”