Halogen Photoelimination from Sb^V Dihalide Corroles

Abstract

Main-group p-block metals are ideally suited for mediating two-electron reactions because they cycle between M and M redox states, as the one-electron state is thermodynamically unstable. Here, we report the synthesis and structure of an Sb corrole and its SbX (X = Cl, Br) congeners. Sb sits above the corrole ring, whereas Sb resides in the corrole centroid. Electrochemistry suggests interconversion between the Sb and SbX species. TD-DFT calculations indicate a HOMO → LUMO+2 parentage for excited states in the Soret spectral region that have significant antibonding character with respect to the Sb-X fragment. The photochemistry of 2 and 3 in THF is consistent with the computational results, as steady-state photolysis at wavelengths coincident with the Soret absorption of SbX corrole lead to its clean conversion to the Sb corrole. This ability to photoactivate the Sb-X bond reflects the proclivity of the pnictogens to rely on the Pn couple to drive the two-electron photochemistry of M-X bond activation, an essential transformation needed to develop HX-splitting cycles.

Photodriven Elimination of Chlorine From Germanium and Platinum in a Dinuclear PtII→GeIV Complex

“…We reported that [( o ‐dppp) 2 Cl 3 Sb V ]Pd II Cl 2 ( B , o ‐dppp= o ‐(Ph 2 P)C 6 H 4 ) (Figure 1) undergoes a clean photoreductive chlorine elimination reaction, which produces [( o ‐dppp) 2 Cl 2 Sb IV ]Pd I Cl, thus suggesting that antimony can support the photoreductive elimination of chlorine [7] . Nocera confirmed this possibility by describing an antimony(V)‐corrole dihalide C (Figure 1), which can also be reduced into the corresponding antimony(III)‐corrole by irradiation [8] . With the view of broadening the type of elements that support this photoreductive chemistry, we put forth the hypothesis that group 14 elements with accessible II/IV oxidation states may also be prone to photoreduction via halogen evolution.…”

“…[7] Nocera confirmed this possibility by describing an antimony(V)corrole dihalide C (Figure 1), which can also be reduced into the corresponding antimony(III)-corrole by irradiation. [8] With the view of broadening the type of elements that support this photoreductive chemistry,w ep ut forth the hypothesis that group 14 elements with accessible II/IV oxidation states may also be prone to photoreduction via halogen evolution. To explore this possibility and elaborating on our prior investigation of complexes of type B, [7] we have now decided to investigate platinum-germanium complexes with ad inuclear core designed to support the coveted lightdriven elimination process.…”

Redox chemistry of π-extended tellurophenes

“…edox reactions are important chemical and biochemical processes that occur in nature and a range of synthetic compounds of interest for catalysis and energy transfer and storage. Most of these reactions involve transition metal complexes, however, recent emphasis has been placed on main group inorganic compounds due to their lightweight and more abundant nature [1][2][3][4][5][6] . In this context, tellurophene, a telluriumcontaining five-membered aromatic ring 7,8 , is of particular interest given that its π-delocalized nature resembles more traditional aromatic heterocycles and that it incorporates a metalloid that is capable of several stable oxidation states 9-11 . In the last decade, the incorporation of the tellurophene-motif into π-extended molecules and polymers has been recognized as a promising design for electronic devices, such as thin film transistors, light emitters, photovoltaics, and thermoelectrics [12][13][14][15][16][17][18][19][20][21][22][23][24][25] .…”

Polystyrene Oxygen Optodes Doped with Ir(III) and Pd(II) meso-Tetrakis(pentafluorophenyl)porphyrin Using an LED-Based High-Sensitivity Phosphorimeter

“…The polystyrene itself is prone to photodegradation, but much more slowly than the indicators [ 50 ]. In theory, violet excitation of the IrTFPP-CO-Cl could generate chloride radicals that would decompose the metalloporphyrin [ 54 ]. In addition, also the release of the CO ligand could lead to a less stable five-coordinate complex; thus, both effects contribute to the lower stability of the Ir(III) complex.…”