Peculiar reactivity of face to face biscorrole and porphyrin–corrole with a nickel(II) salt. X-Ray structural characterization of a new nickel(II) bisoxocorrole

Abstract

New nickel(II) bisoxocorrole complexes have been synthesized and characterized. Two nickel bisoxocorrole isomer complexes are formed in a 1:1 ratio when a biscorrole, where an anthracenyl bridge links the two macrocycles in a face to face arrangement, is metallated by nickel in air. Evidence for the insertion of an oxo group at one of the meso positions is given by the X-ray structural characterization of the Ni₂(BOCA) “cis” isomer where BOCA is a bisoxocorrole with an anthracenyl spacer. Conversely, under the same reaction conditions no nickel bisoxocorrole is obtained when biphenylene is the linker of the biscorrole system, the major product of the reaction being a bisnickel bisradical species. Only a small amount of a bisnickel hydrooxobiscorrole is isolated in this reaction. A reaction mechanism for both series (anthracenyl and biphenylenyl) is given and a comparison of the behavior of the biscorrole system with related derivatives is proposed.