Syntheses and structural characterization of some mono- and di-p-nitrophenyl(3)ferrocenophanes: X-ray structure of (3)ferrocenophane, 3-p-nitrophenyl(3)ferrocenophane, and 3,4-bis-(p-nitrophenyl)(3)ferrocenophane; DFT calculations on ferrocene derivatives

Abstract [3]Ferrocenophane ( 3a ) reacts in a Gomberg reaction with diazotized p -nitroaniline to give a mixture of mono- and di-substituted products. The isomeric pairs of 3- and 2-( p -nitrophenyl)[3]ferrocenophanes ( 4 and 5 ), as well as 3,4′- and 3,4- bis -( p -nitrophenyl)[3]ferrocenophanes ( 6 and 7 ) were separated from the mixture by column chromatography on Al 2 O 3 and characterized by means of mass, IR, UV, 1 H-NMR spectroscopy, and by X-ray analysis ( 4 and 6 ). PM3/tm and density functional theoretical calculations on ferrocene ( 1 ) and ferrocenophane derivatives are reported. A refined X-ray structure determination of [3]ferrocenophane ( 3a ) is given.