Dissymmetrical Chiral Peropyrenes: Synthesis via Iridium-Catalyzed C-H Activation/Alkyne Benzannulation and Study of Their Properties.

Dissymmetrical chiral peropyrenes with electron-rich and electron-deficient aryl substituents in the bay regions were synthesized via iridium-catalyzed C-H activation and alkyne benzannulation. The electronic properties were studied using cyclic and differential pulse voltammetry. The enantiomers were separated and exhibited high glum and gabs values in circularly polarized luminescence (CPL) and circular dichroism (CD), respectively. Variable-temperature NMR experiments were conducted on symmetrical and dissymmetrical chiral peropyrenes to compare the barrier to rotation of the aryl groups in the bay region.

Synthesis of a cobalt(IV) ketimide with a squashed tetrahedral geometry.

Oxidation of [Li(THF)]2[Co(N=C(t)Bu2)4] with 1 equiv. of I2 generates Co(N=C(t)Bu2)4 in 85% yield. In the solid-state, this complex exhibits a squashed tetrahedral structure about the Co center. DFT calculations reveal this geometry arises, in part, to maximize ketimide-to-cobalt π-donation.