η⁶-Coordination of the Curved Carbon Surface of Corannulene (C₂₀H₁₀) to (η⁶-arene)M²⁺(M = Ru, Os)

Reactions of [(η 6 -arene)M(acetone) 3 ]X 2 (M = Ru, Os; X = BF 4, PF 6, or SbF 6 ) with 1 equiv of the curved-surface buckybowl, corannulene (C 20 H 10, 1 ), in CD 3 NO 2 afford quantitatively the η 6 -coordinated complexes [(η 6 -C 6 Me 6 )Ru(η 6 -C 20 H 10 )]X 2 ( 3a, X = SbF 6; 3b, X = PF 6; 3c, X = BF 4 ), [(η 6 -C 6 HMe 5 )Ru(η 6 -C 20 H 10 )](SbF 6 ) 2 ( 4 ), [(η 6 -C 6 EtMe 5 )Ru(η 6 -C 20 H 10 )](SbF 6 ) 2 ( 5 ), and [(η 6 -cymene)Os(η 6 -C 20 H 10 )](SbF 6 ) 2 ( 6 ). In the solid state, yellow complexes 3 − 6 are stable in dry air for several months and have all been characterized by their 1 H, 13 C{ 1 H}, and COSY NMR, mass spectra, elemental analyses, and X-ray diffraction; the corannulene in the complexes is slightly flattened as compared with free corannulene, 1 . Even in the presence of excess [(η 6 -arene)M(acetone) 3 ]X 2, it was not possible to add two (η 6 -arene)M 2+ units to 1 . The corannulene ligand in 3a is susceptible to nucleophilic attack by phosphines to give a mixture of adducts.