Deprotonation of β‐Diketiminate in Sterically Demanding β‐(Diketiminato)lanthanide Complexes: Influence of Lanthanide Metals

Abstract

Attempted synthesis of tris(β‐diketiminato)lanthanide complexes [Ln(L)3] (L = [{N(C6H3Me2‐2,6)C(Me)}2CH]) resulted in ligand deprotonation, and different outcomes depending on the central metal used were observed. Reaction of YbCl3 with NaL (3 equiv.) afforded the five‐membered cyclometalated ytterbium β‐diketiminate complex [Yb(L)(L)dep] (1). The same reaction with LnCl3 (Ln = Nd, Sm, and Er) gave the new complexes composed of one normal L and one deprotonated neighboring benzazacyclopentane ligand derived from deprotonation of the 2‐methyl group followed by an attack of thecarbon atom on the β‐diketiminate backbone, [Ln(L)(L)dep′(thf)] [Ln = Nd (2), Sm (3), and Er (4)]. The bonding mode in the {Ln(L)dep′} moiety was also found to depend on the central metal ions.

Early/Late Heterobimetallic Tantalum/Rhodium Species Assembled Through a Novel Bifunctional NHC‐OH Ligand

“…Intramolecular C−H bond activation of alkyl and aryl ligand substituents in metal–NHC complexes has been observed previously with various metals . Intramolecular ligand C−H bond activation leading to cyclometallated species is also well documented for alkylidene, alkyl and hydride complexes of tantalum and other early TMs . The structure of 5 was determined by advanced 1D and 2D 1 H and 13 C NMR studies.…”

On the non-innocence of “Nacnacs”: ligand-based reactivity in β-diketiminate supported coordination compounds

“…In contrast, ligand substitution reactions are observed with PhLi and LiNEt 3 . 225 Several examples where a BDI aryl substituent is activated are known but these typically yield metallacyclic derivatives as described in section 10. 20).…”

“…For instance, in the crystal structure of [K(THF) 4 ][(#BDI*) 2 La], the unites are connected in a 1-dimensional coordination polymer by bridging potassium counter-cations bound to the deprotonated ligand methylene groups (Scheme 59). 225 Hydrogen atoms have been omitted for clarity. 21, formed by reaction of Na(NSiMe 3 ) 2 with a dichloro BDI Sc(III) complex (Scheme 59).…”

β-Diketiminate Rare Earth Borohydride Complexes: Synthesis, Structure, and Catalytic Activity in the Ring-Opening Polymerization of ε-Caprolactone and Trimethylene Carbonate

“…Regarding β-diketiminate borohydride complexes, their limited number is rather surprising since β-diketiminates, often denoted as “NacNac”, are very popular ancillary ligands for most elements of the periodic table. − Even in rare earth chemistry, β-diketiminates have been widely used for the synthesis of trivalent compounds. ,,− In contrast, divalent rare earth β-diketiminates have been neglected, and to our knowledge, only a few structurally characterized complexes have been reported. ,− …”