Abstract:
Metalla-analogues of archetypal aromatic molecules are attracting ever increasing interest. Although metallabenzenes (which fall within this class) have been well studied, fused-ring metallabenzenes are rare and of the linear polycyclic metallaaromatic hydrocarbons, only metallanaphthalene is known. Herein we report the first metallaanthracene, [Ir(C13 H8 {CH2 CO2 Me-5})Cl(PPh3 )2 ]O3 SCF3 (5), which represents the next member of this series of polycyclic compounds. Structurally, 5 has a number of features in common with anthracene including fused-ring planarity and bond-length alternation. In analogues of classic reactions of anthracene, 5 forms a Diels-Alder adduct with maleic anhydride and on oxidation the unprecedented fused-ring metallaanthraquinone, [Ir(C15 H6 O{Br-6}{OMe-7}{=O-8}{=O-15})Br(PPh3 )2 ], is obtained.