Reactions of pyridine-2-ethyl/methyl cyclopentadienes with metal carbonyls

Abstract

Thermal treatment of pyridine-2-ethyl cyclopentadiene (1) with Fe(CO)5 and Ru3(CO)12 gave novel intramolecular C–H activated dinuclear products (3 and 5). In the case of Fe(CO)5, the reaction also afforded the normal bis(cyclopentadienyl) diiron complex (4). However, similar reaction of pyridine-2-methyl cyclopentadiene (2) with Fe(CO)5 and Ru3(CO)12 only afforded the normal bis(cyclopentadienyl) dinuclear metal complexes (7 and 8). For Ru3(CO)12, the reaction also yielded a pendant η1-pyridyl-coordinated product (9). In addition, the reactions of 1 and 2 with Re2(CO)10 formed the corresponding pyridylethyl/pyridylmethyl cyclopentadienyl rhenium tricarbonyl complexes 10 and 11, which further underwent pyridine to rhenium cyclization via photoirradiation to provide the rhenium dicarbonyl complexes 12 and 13. The molecular structures of 3, 5, 6, 7, 8, 9, and 12 were determined by X-ray diffraction.