Halterman Corroles and Their Use as a Probe of the Conformational Dynamics of the Inherently Chiral Copper Corrole Chromophore

Kolle E Thomas (1) , Laura J Mccormick (2) , Daniel Carrie (3) , Hugo Vazquez-Lima (1) , Gerard Simonneaux (3) , Abhik Ghosh (1)

1 UiT - The Arctic University of Norway [Tromsø, Norway]
2 LBNL - Lawrence Berkeley National Laboratory [Berkeley]
3 ISCR - Institut des Sciences Chimiques de Rennes

Halterman corroles have been synthesized for the first time from pyrrole and Halterman's aldehyde via Gryko's "water-methanol method". These were derivatized to the corresponding copper complexes and subsequently to the β-octabromo complexes. Electronic circular dichroism spectra were recorded for the enantiopure copper complexes, affording the first such measurements for the inherently chiral Cu corrole chromophore. Interestingly, for a given configuration of the Halterman substituents, X-ray crystallographic studies revealed both P and M conformations of the Cu-corrole core, proving that the substituents, even in conjunction with β-octabromination, are unable to lock the Cu-corrole core into a given chirality. The overall body of evidence strongly indicates a dynamic equilibrium between the P and M conformations. Such an interconversion, which presumably proceeds via saddling inversion, provides a rationale for our failure so far to resolve sterically hindered Cu corroles into their constituent enantiomers by means of chiral HPLC.

Domains: Chemical Sciences; Coordination chemistry

Kolle E Thomas, Laura J Mccormick, Daniel Carrie, Hugo Vazquez-Lima, Gerard Simonneaux, et al.. Halterman Corroles and Their Use as a Probe of the Conformational Dynamics of the Inherently Chiral Copper Corrole Chromophore. Inorganic Chemistry, 2018, 57 (8), pp.4270-4276. ⟨10.1021/acs.inorgchem.7b02767⟩. ⟨hal-01771518⟩