Cobalt(II) Carboxylate Chemistry and Catalytic Applications

Synthesis, polymorphism, and shape complementarity-induced co-crystallization of hexanuclear Co(ii) clusters capped by a flexible heteroligand shell

“…Numerous previous studies showed that the application of auxiliary stabilizing ligands enables the control over the structure and nuclearity of cobalt( ii ) acetato clusters, however, still in a highly unpredictable manner. 19 With this in mind, we selected 2-pyrrolidinoethoxylate ( pyret ) as a model O , N -bidentate ligand in order to study their role in the stabilization of cobalt( ii ) carboxylates. Our primary attempts to isolate well-defined crystalline products via the direct reaction of Co(OAc) 2 or Co(OAc) 2 ·4H 2 O with pyret -H afforded an intractable mixture of products.…”

“…15–17 On the other hand, polynuclear cobalt clusters are of longstanding interest, owing to their promising magnetic 18,19 and catalytic properties, 20 as well as their applications as metalloenzyme models. 21–23 In this view, carboxylate-supported systems are of particular interest due to the versatility of binding modes of carboxylate ligands, 19,24 the propensity of carboxylate bridges to mediate magnetic interactions, 19,23–25 and the prevalence of carboxylic moieties in biological systems. 21,26,27 However, cobalt carboxylates exhibit extensive stoichiometric and structural diversity and the development of reliable synthetic routes to oligomeric cobalt carboxylato clusters with controllable structure and reactivity is highly challenging.…”

“…21,26,27 However, cobalt carboxylates exhibit extensive stoichiometric and structural diversity and the development of reliable synthetic routes to oligomeric cobalt carboxylato clusters with controllable structure and reactivity is highly challenging. 19 Even simple homoleptic Co( ii ) carboxylates form diverse hydrates that can be easily transformed into various cobalt oxido- and hydroxido-carboxylato clusters, which structure is strongly affected by the reaction conditions. 28 Further control over the structure of cobalt carboxylates may be achieved by the introduction of auxiliary stabilizing neutral or anionic ligands that paved the way for a wide range of heteroleptic clusters with nuclearity ranging from mononuclear to approaching the size of nanoparticles.…”

“…28 Further control over the structure of cobalt carboxylates may be achieved by the introduction of auxiliary stabilizing neutral or anionic ligands that paved the way for a wide range of heteroleptic clusters with nuclearity ranging from mononuclear to approaching the size of nanoparticles. 19,29 Notably, these organic ligands also participate in intermolecular interactions governing the self-assembly of metal clusters in the crystal lattice. Thus, the utilization of new compounds for the stabilization of Co( ii ) complexes is a promising strategy in the development of new cobalt clusters-based functional materials.…”

Bidentate Geometry-Constrained Iminopyridyl Ligands in Cobalt Catalysis: Highly Markovnikov-Selective Hydrosilylation of Alkynes

“…The coordination spheres of the terminal cobalt atom are completed by two nitrogen atoms of a bidentate CImPy ligand to form a distorted octahedron configuration. Compared to the reported trinuclear cobalt complexes with bidentate nitrogen ligands, the steric DIPP and methyl groups from CImPy ligands clearly produce a congested environment favorable in protecting the terminal cobalt centers . Using Co1 as the catalyst, phenylacetylene was successfully hydrosilylated with PhSiH 3 in a quantitative conversion.…”