Yttrium Hydride Complex Bearing CpPN/Amidinate Heteroleptic Ligands: Synthesis, Structure, and Reactivity

Abstract

The reaction of the yttrium dialkyls (C 5 H 4 − PPh 2 N−C 6 H 3 i Pr 2 )Y(CH 2 SiMe 3 ) 2 (thf) (1) with an excess of N,N′-diisopropylcarbodiimide gave the yttrium monoalkyl complex (C 5 H 4 −PPh 2 N−C 6 H 3 i Pr 2 )Y(CH 2 SiMe 3 )[ i PrN C(CH 2 SiMe 3 )−N i Pr] (2). 2 subsequently reacted with 1 equiv of PhSiH 3 to generate the CpPN/amidinate heteroleptic yttrium hydride {(C 5 H 4 −PPh 2 N−C 6 H 3 i Pr 2 )Y[ i PrNC-(CH 2 SiMe 3 )−N i Pr](μ-H)} 2 (3). Hydride 3 showed good reactivity toward various substrates containing unsaturated C− C, C−N, and N−N bonds, such as azobenzene, p-tolyacetylene, 1,4-bis(trimethylsilyl)-1,3-butanediyne, N,N′-diisopropylcarbodiimide, and 4-dimethylaminopyridine, affording the yttrium hydrazide complex 4 with a rare η 2 -Cp bonding mode, yttrium terminal alkynyl complex 5, yttrium η 3 -propargyl complex 6, yttrium amidinate complex 7, and yttrium 2-hydro-4dimethylaminopyridyl product 8, respectively.

Rare‐Earth Metal Complexes with Terminal Imido Ligands

“…The (Tp t Bu,Me ) ligand coordinates in the routinely observed κ 3 mode (cf., 1 , 2 , 4 ), the DMAP donor and the imide ligand terminally through the nitrogen atoms. The Y–N(DMAP) distance of 2.426(4) Å is comparable to the pyrazole nitrogen bond lengths [2.459(4)–2.491(3) Å] and those found in other complexes ligated by DMAP, [{Y{N(SiMe 3 ) 2 } 2 (DMAP)} 2 (μ‐η 2 :η 2 ‐N 2 )] [2.459(1) Å]22 and [(C 5 H 4 –PPh 2 =NC 6 H 3 i Pr 2 )Y{ i PrNC(CH 2 SiMe 3 )N i Pr}(DMAP)(η 1 ‐NC 5 H 5 ‐ p ‐NMe 2 )] [2.467(5) Å] 23. The Y–N(imido) bond length of 2.024(4) Å is significantly shorter than those in imidazoline–iminato complexes, for example, [(Im Dipp N)Y(η 5 ‐C 2 B 9 H 11 )(thf) 2 ] {2.083(2) Å},24 LA‐stabilized imide complex 2 (av.…”

Reactivity of the Y3+ Tuck-Over Hydride Complex, (C5Me5)2Y(μ-H)(μ-CH2C5Me4)Y(C5Me5)

“…To determine if the reactivity of the (C 5 Me 4 CH 2 ) 2– and (H) − ligands in 1 could be differentiated by insertion as well as by the PhSH reaction described above, reactivity with a carbodiimide was investigated. Carbodiimides are known to insert into both M–H and M–C bonds . However, the reaction of 1 with diisopropylcarbodiimide gives a product, 7 , that has analytical and spectroscopic characteristics consistent with insertion into both Y–H and Y–C bonds, namely, (C 5 Me 5 ) 2 Y{μ-η 5 - C 5 Me 4 CH 2 [ i PrNCN i Pr-κ 2 N , N ′]}Y(C 5 Me 5 )[ i PrNC(H)N i Pr-κ 2 N , N ′] (eq ).…”

Tetrahydropentalenyl-phosphazene constrained geometry complexes of rare-earth metal alkyls

“…18 Moreover, the reactivity toward various substrates was recently studied and, among others, CpPN amidinate, hydride and terminal imido complexes were synthesized, characterized and their reactivity was probed. 19 These current developments reveal that CpPN type complexes appear to be a promising class of catalysts. Therefore it is of general and fundamental interest to develop novel, sterically most demanding and rigid CpPN type ligands as useful building blocks and to study their stabilizing properties for dialkyls of the smallest and larger rare-earth metal cations (Sc, Lu, Y, Yb, Sm, Nd and Pr).…”

“…There are also some complexes bearing monoanionic ligands which are isoelectronically related to the classical dianionic CpSiN ligand system such as CpSiNP (D), 13 CpSiNIm (E) 14 and the cyclopentadienyl-phosphazenes (CpPN) (F) that is the focus of our current investigation. [15][16][17][18][19] Previously we reported a general and convenient synthetic protocol for a large variety of CpPN type ligands, 20 and their use in the stabilization of highly reactive alkyls of rare-earth and group 4 metals has been claimed. 21 Independently, related fluorenyl-and indenyl-phosphazene ligands (FluPN and IndPN) and their rhodium 22 and zirconium 23 complexes were presented by Bourissou and co-workers.…”