Crystal structure and conformation of bis-(tricarbonyliron)heptalene

Abstract

Fe 2C 18O 6H 10 is monoclinic, space group P2 1/ n with a = 12.517, b = 12.661, c = 10.632 Å, β = 90.92°, Z = 4. The structure was refined to R = 0.024 for 2702 counter reflections. The two outer butadiene moietes are exo complexed with tricarbonyliron units, thus forming tetragonal pyramidal iron complexes. The seven-membered rings of the heptalene have boat conformations with a flat central region and structure angles α = 6° and β = 41°. The molecules are packed in chains along the a-direction with shortest intermolecular distances between carbonyl units.