Light- and Heat-Controlled Formation of Osmanaphthalenes and Osmanaphthalynes

摘要

Comprehensive Summary Simple 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.

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