Synthesis and X‐ray Crystal Structures of β‐Ketoiminate Complexes

Abstract

Heteroleptic zinc complexes containing side‐arm donor‐functionalized tridentate β‐ketoiminate ligands were obtained from metalation reactions of β‐ketoimines L1/2/3Do1/2/3/4H [L1 = {(OC(Me)C(H)C(Me)NCH2CH2Do)}, L2 = {(OC(Me)C(H)C(Me)NCH2CH2CH2Do)}, L3 = {(OC(OMe)C(H)C(Me)NCH2CH2Do)}; Do1 = NMe2, Do2 = NEt2; Do3 = Pyr, Do4 = OMe] with equimolar amounts of Zn[N(SiMe3)2]2 [L1Do1ZnN(SiMe3)2 (1), L1Do2ZnN(SiMe3)2 (2)] and ZnEt2 [L1Do3ZnEt (3), L2Do3ZnEt (4), L3Do1ZnEt (5), L3Do4ZnEt (6)]. Analogous reactions of AlMe3 and Cp*MMe3 with L1Do1/2H yielded homoleptic aluminum [L1Do1AlMe2 (7), L1Do2AlMe2 (8), L2Do1AlMe2 (9)], titanium [L1Do2Ti(Me2)Cp* (10)] and zirconium complexes [L1Do2Zr(Me2)Cp* (11)]. In addition, 7 reacts with an ethereal HCl solution with methane elimination and formation of L1Do1Al(Cl)Me (12) and L1Do1AlCl2 (13), whereas the reaction with one and two equivalents of 2,6‐dimethylphenol yielded L1Do1Al(Me)O‐2,6‐Me2C6H3 (14) and L1Do1Al(O‐2,6‐Me2C6H3)2 (15). The complexes were characterized by elemental analysis, 1H, 13C NMR, and IR spectroscopy and single‐crystal X‐ray analysis (2, 4, 7, 10, 12–14).

Investigations into the structure, reactivity, and AACVD of aluminium and gallium amidoenoate complexes

“…Please do not adjust margins All Al-heteroatom bonds in 1-Al were found to be significantly shorter than the 5-coordinate complexes reported by Richards and Shulz previously, 40,41 which is likely a consequence of the comparatively electron deficient nature of the aluminum center in 1-Al. Complexes 2-Al and 3-Al both displayed a distorted trigonal bipyramidal geometry with a  4 value of 0.87 for 2-Al and 0.76 for 3-Al, suggesting that the Dip-substituted amidoeanote ligands in 3-Al distort the geometry of the aluminium center significantly more than the iPr-substituents in 2-Al.…”

“…Complex 1-Al represents the first example of a tetrahedral aluminium dichloride unit featuring a ligand that binds through both oxygen and nitrogen and was synthesised from the salt metathesis reaction of [Li(AME iPr )] and AlCl 3 (Scheme 1). Two previous examples of aluminium dichlorides featuring (O,N)-binding ligands have been reported by Richards 40 and Shulz, 41 with the formulae [AlCl 2 {(RNC(Me)CHC(Me)O}], R = Fig. 2 Previously reported zinc bis-amidoenoates (A and B), ethyl zinc amidoenoate dimers (C and D) and tungsten amidoenoate complexes (E and F).…”

Tris(β‐ketoiminate) Aluminium(III) Compounds as Aluminium Oxide Precursors

“…There are also known examples of β-ketoimine compounds where the careful choice of the R group leads to ligand systems with a greater denticity than two. [22,23] As with β-diketones, all Al complexes containing βketoiminates ligands feature Al(III). Interestingly, mono-and bisligated systems using these ligands are much more common than the β-diketonates, with the prevalence of heteroleptic structures being much greater.…”

“…Many variations of β ‐ ketoimine compounds have been prepared, including examples containing alkyl, [19] aryl [20] and silyl [21] R groups. There are also known examples of β ‐ ketoimine compounds where the careful choice of the R group leads to ligand systems with a greater denticity than two [22,23] …”