Lewis basicity of the [Co₄O₄]⁴⁺cubane core. Preparation of a mixed-valence (4Co^II, 4Co^III) cluster with an unusual [Co₈(µ₄-O)₄]²⁺core, and new [Co₄O₃(OH)]⁵⁺and [Co₄O₂(OH)₂]⁶⁺cubane complexes

Abstract

I b is formed on oxidation of cobalt(ii) benzoate in MeCN or dmf with aqueous H202, and contains a [Co40414+ cubane unit with each oxide attached to an additional Co atom; studies stimulated by this result show that preformed [C0~04(02CR)~( bipy),]Z+ (bipy = 2,T-bipyridine) can be mono-and dou bly-protonated to [Co403(0H )(02CR)2( bi ~y ) ~1 3 + and [Co4O2(OH),( 02CR),( bi ~y ) ~] 4 + , respectively.

Hydrothermal Synthesis and Structural Characterization of a Coordination Polymer Containing Heptanuclear Co7(μ3-OH)8 Clusters

“…Consequently, each Co 7 (μ 3 -OH) 8 cluster in 1 is linked through six oxalate ligands and six piperazine ligands to 12 other Co 7 (μ 3 -OH) 8 clusters. Heptanuclear cobalt complexes containing N-donor and O-donor ligands are rare, and the known examples have a very irregular shape. , While cobalt−oxygen clusters of single cubane, face-shared triple cubanes, and some other polynuclear cobalt−oxygen compounds have been reported, the cobalt−hydroxyl cluster of corner-shared double cubanes is unprecedented. The hydroxo-bridged heptanuclear metal cluster of the fused double-cubane type is only known for copper .…”

[Co4O4]4+ Cubane Core as a Brønsted Base: Preparation and Properties of [Co4O3(OH)(O2CR)2(bpy)2]3+ and [Co4O2(OH)2(O2CR)2(bpy)2]4+ Salts

“…This has proved to be the case, and this paper describes the preparation and characterization of mono- and diprotonated derivatives of the [Co 4 O 4 ] 4+ core. Portions of this work have been briefly communicated …”

Toward Models for the Full Oxygen-Evolving Complex of Photosystem II by Ligand Coordination To Lower the Symmetry of the Mn3CaO4 Cubane: Demonstration That Electronic Effects Facilitate Binding of a Fifth Metal

“…With the increased Lewis basicity of μ 3 -oxo O2 established, binding of a “dangler” metal instead of a proton at this position was targeted to model the Mn 3 CaO 4 + M′ geometry of the OEC. 12 Addition of metal triflate salts of Ag + , Mn 2+ , and Co 2+ to 5 led to changes in the 1 H NMR and ESI-MS spectra, indicative of productive reactions (see SI ). None showed loss of Ca 2+ as compared to 1 , a crucial finding for further cluster elaboration.…”