Acetylacetonato cobalt(III) and iron(III) complexes of picolylamine- and aminopropylamine-bis(phenolate) ligands: Synthesis, characterization and crystal structures

Abstract

The reaction between [M(acac)3] (M = Fe, Co, acac = acetylacetonate) and the diamino-bis(phenol) proligands (2-OH-3,5t Bu2-C6H2CH2)2NCH2(2-NC5H4) (H21) and (2-OH-5t Bu-C6H3CH2)2NCH2CH2CH2N(CH3)2 (H22) afforded the [κ 4-(N2,O2)M(acac)] complexes [Fe(1)(acac)] (3), [Fe(2)(acac)] (4), [Co(1)(acac)] (5) and [Co(2)(acac)] (6) in moderate yields after crystallization. The proposed formulas were supported by various analytical data (ESI-MS, FT-IR, EA, NMR), and the molecular structure of all complexes was confirmed by X-ray diffraction studies. In each octahedral complex, the diamino-bis(phenolate) ligand (1 or 2) acts as a tetradentate ligand and the coordination sphere is completed by one chelating κ 2-O2 acac ligand. Although the previously reported ligand 1 and the new ligand 2 are very similar, their coordination to the Fe III (acac) or Co III (acac) moieties varies by the arrangement of the donor atoms. While the Ophenolate donor atoms of ligand 1 were found cis to each other in the Fe III complex 3, they are trans in the Co III complex 5, and vice versa for ligand 2. Since each ligand, 1 and 2, exhibits both configuration, this structural curiosity cannot be easily explained on the basis of steric factors, i.e. ortho-substituents or N,N'-linker length.

Synthesis, Characterization, and Catalytic Study of Amine-Bridged Bis(phenolato) Co(II) and Co(II/III)-M(I) Complexes (M = K or Na)

“…Methods for preparing Co­(III) complexes reported in the literature include mainly reaction of ligand precursors with Co­(III) salts and oxidation of Co­(II) complexes with oxidants such as oxygen and Ag + . ,,, However, attempts to synthesize the Co­(III) complex from reaction of L 1 H 3 , NEt 3 , and trivalent cobalt precursor Co­(acac) 3 were unsuccessful.…”

Crystal structure and Hirshfeld surface analysis of the product of the ring-opening reaction of a dihydrobenzoxazine: 6,6′-[(cyclohexylazanediyl)bis(methylene)]bis(2,4-dimethylphenol)

“…Dihydro-benzoxazine dimer derivatives with para substituents are very common, viz. Redjel et al, 2018). Apart from the monosubstituted derivatives, there are some reports on the crystal structures of ortho and para disubstituted derivatives, e.g., HEPZOU (Zhang et al, 2018) and RACMEP (Lionetti et al, 2010).…”

Cobalt complexes of an OSNSO-tetrapodal pentadentate ligand: Synthesis, structures and reactivity

“…While the low valent metal complex ([L/Mt x ]) acts as activator of the halogen-capped dormant chain (P-Y) in ATRP, leading to the active radical species (P • ) and the deactivator ([L/Mt x+1 -Y]), it serves as deactivator in OMRP, via direct carbon/polymer-metal bond formation, resulting in an organometallic dormant species ([L/Mt x+1 -P], Scheme 1). Recently, we focused our attention on the development of iron-based moderating systems for the ATRP of reactive monomers such as methyl methacrylate (MMA) [21][22][23], and on manganese- [24,25] and cobalt-based systems [26][27][28][29][30][31][32][33] for the OMRP of less activated monomers (LAMs = monomers leading to poorly stabilized radicals) such as vinyl acetate (VAc) or vinylidene fluoride (VDF).…”