Accessing Three Oxidation States of Cobalt in M6L3 Nanoprisms with Cobalt-Porphyrin Walls

Abstract

Nanocages with porphyrin walls are common, but studies of such structures hosting redox-active metals are rare. Pt-linked M6L3 nanoprisms with cobalt-porphyrin walls were prepared and their redox properties were evaluated electrochemically and chemically, leading to the first time that cobalt-porphyrin nanocages have been characterized in Co(I), Co(II), and Co(III) states.

Electrocatalytic production of hydrogen peroxide enabled by post-synthetic modification of a self-assembled porphyrin cube

“…To circumvent this, we hypothesized that a post-synthetic metalation could be used with a free-base porphyrin cube. This has been demonstrated on trimeric porphyrin barrels synthesized by Lipke et al 33 The free-base porphyrin cube, FeH 2 -cube, was synthesized according to literature protocol (see Fig. 2).…”

“…16,36 Closer inspection of the 0 to 20 ppm range reveals broad resonances characteristics of square planar Co(II) porphyrin with a single unpaired electron per porphyrin-ligated metal centre. 33 Electron paramagnetic resonance (EPR) informed on the spin states and local structure of paramagnetic centres. The 77 K X-band EPR of CuTAPP starting material shows an axial signal for an S = 1 2 spin system (see Fig.…”

“…S14 †), in excellent agreement with other Co(I) porphyrin species. 45 To screen CoCo-cube for catalytic activity, cyclic voltammograms were acquired under catalytically relevant conditions. When the nitrogen atmosphere was replaced with oxygen, no major current response was observed until the formation of superoxide by the glassy carbon working electrode (brown trace in Fig.…”

Mingling Light, Oxygen, and Organometallics to Form Cobalt-Carbon Bonds in the Confines of a Metal-Organic Nanocage

“…Since [(TPyMeP)Co III Me] 4+ was not formed cleanly using SnMe4, the identity of this Co III Me complex was confirmed by independent synthesis using Me3O + to alkylate the reduced complex [(TPyMeP)Co I ] 3+ (see Supporting Information). 24 Figure 5. 1 H NMR monitoring of the reaction of (TPyMeP)Co II with excess SnMe4 (50 equiv) in CD3CN in the presence of air and ambient light at 23 °C.…”