Light‐ and Heat‐Controlled Formation of Osmanaphthalenes and Osmanaphthalynes

Abstract

Comprehensive SummarySimple and efficient synthesis of metalla‐aromatics with tailored distinctive optical, magnetic, redox, and light‐emitting properties is attractive yet challenging. We have now successfully synthesized three paramagnetic osmanaphthalenes bearing different electron‐donating groups as well as the first osmabenzo[b]carbazole containing an osmanaphthalene unit with four fused rings in good yields by subjecting suitable osmium carbyne precursors to a visible‐light‐induced protocol. In contrast, the four corresponding diamagnetic cyclic metal carbynes containing an osmanaphthalyne unit were obtained from the same osmium carbyne precursors by a heating method. The lowest‐energy absorptions of the paramagnetic osmanaphthalenes are red‐shifted compared to the corresponding osmanaphthalynes. Additionally, experimental observations including X‐ray analysis as well as nucleus‐independent chemical shift (NICS), anisotropy of the current‐induced density (AICD) calculations revealed these novel osmapolycycles bearing phosphonium substituents to be of aromatic character.