Diphenoxido‐Bridged Co^II and Zn^II Complexes of Tripodal N₂O₂ Ligands: Stabilisation of M^II‐Coordinated Phenoxyl Radical Species

Abstract

Three new tripodal ligands with an N 2 O 2 donor set, namely 2-tert-butyl-6-({(2-hydroxybenzyl) [2-(2-pyridyl)

Versatile cobalt complexes for initiating immortal ring‐opening polymerization (ROP) of lactide (LA), mediating living radical polymerization of t‐butyl acrylate (tBA) and catalyzing copolymerization of LA and tBA by combination of ROP and organometallic‐mediated radical polymerization

“…All substituted amino‐bis(phenolate) ligands (L 1 H 2 –L 5 H 2 ) were prepared using modified literature procedures employing Mannich condensation of the corresponding amine, phenol and formaldehyde in a one‐pot reaction with ethanol heated to reflux for 5–20 h (Scheme S1, supporting Information) . The cobalt complexes 1 – 5 were facilely synthesized, as shown in Scheme S1, by reacting cobalt acetate tetrahydrate with the respective ligand in methanol solution heated to reflux for 5 h . The cobalt complexes in the solid state are stable at room temperature.…”

“…All substituted amino-bis(phenolate) ligands (L 1 H 2 -L 5 H 2 ) were prepared using modified literature procedures employing Mannich condensation of the corresponding amine, phenol and formaldehyde in a one-pot reaction with ethanol heated to reflux for 5-20 h (Scheme S1, supporting Information). [39][40][41] The cobalt complexes 1-5 were facilely synthesized, as shown in Scheme S1, by reacting cobalt acetate tetrahydrate with the respective ligand in methanol solution heated to reflux for 5 h. [42] The cobalt complexes in the solid state are stable at room temperature. Recently, Rieger and co-workers reported cobalt complexes of similar structure to be active in the copolymerization of CO 2 and cyclohexene oxide (CHO), which show good activity for the formation of cyclic propylene carbonate in combination.…”

Isostructural Dinuclear Phenoxo-/Acetato-Bridged Manganese(II), Cobalt(II), and Zinc(II) Complexes with Labile Sites: Kinetics of Transesterification of 2-Hydroxypropyl-p-nitrophenylphosphate

“…In this case, the γ angle is 112.2°, a value somewhat smaller than that observed in 2b ·2MeCN (γ = 112.8°); therefore, this complex still exhibits an antiferromagnetic coupling that is very weak in magnitude ( J = −0.4 cm –1 ). Finally, two dicobalt­(II) complexes, one of them having a bis-μ-oxo (phenolate) bridge (γ = 102°) , and the other one with a μ-oxo (phenolate) (γ = 120°) and a μ 1,3 -acetate ( syn-syn conformation) bridge, could be illustrative for the relative importance of each type of bridge on the overall magnetic coupling. The J value for the former is −5.2 cm –1 , whereas that for the latter is −7.3 cm –1 .…”