Sawhorse-type diruthenium tetracarbonyl complexes derived from pyrenyl-carboxylic acids

Sawhorse-type diruthenium tetracarbonyl complexes contg. pyrenyl groups in the equatorial positions of the diruthenium backbone were synthesized and characterized. The reaction between dodecacarbonyltriruthenium Ru3(CO)12 and pyrene-carboxylic acids, 1-pyrenecarboxylic acid (C16H9COOH), 1-pyreneacetic acid (C16H9CH2COOH) and 1-pyrenebutyric acid (C16H9(CH2)3COOH), followed by addn. of axial ligands (L), pyridine (a) and triphenylphosphine (b), affords the stable diruthenium tetracarbonyl complexes, Ru2(CO)4(?2-?2-OOCC16H9)2(L)2 (1), Ru2(CO)4(?2-?2-OOCCH2C16H9)2(L)2 (2) and Ru2(CO)4(?2-?2-OOC(CH2)3C16H9)2(L)2 (3), resp. The mol. structure of the triphenylphosphine derivs. Ru2(CO)4(?2-?2-OOCC16H9)2(PPh3)2 (1b), Ru2(CO)4(?2-?2-OOCCH2C16H9)2(PPh3)2 (2b) and Ru2(CO)4(?2-?2-OOC(CH2)3C16H9)2(PPh3)2 (3b) was detd. by single-crystal x-ray structure anal. and showed a typical diruthenium tetracarbonyl backbone bridged by the pyrene-carboxylato ligands and completed with PPh3 axial ligands. The mol. structure of complexes 2 and 3 reveals that the pyrenyl moieties are adequately positioned to potentially allow these bis-pyrenyl systems to act as mol. tweezers. However, these systems showed no interaction with fullerene in soln., despite possessing, as suggested by mol. modeling, appropriate structural features. [on SciFinder(R)]