The crystal structure of a symmetrical 12-oxa[4,4,3]propella-2,4,7,9-tetraene–bis-irontricarbonyl, C18H12O7Fe2

Abstract

This symmetrical 12-oxa[4.4.3]propella-2,4,7,9-tetraene bis-irontricarbonyl complex, C~sHI207Fe2, m.p.200-204°C, crystallizes in the monoclinic space group C2/c with eight half-molecules in a unit cell of dimensions a=20.791 (3), b=7.173 (1), c= 12"625 (2) A; fl= 111"42 (2) °. The densities are: Dx= 1.713 g.cm -3, D,,= 1.709 g.cm -3. The structure was determined by the heavy-atom method from data collected at room temperature on a four-circle diffractometer using the 0/20 scan technique. It was refined by the least-squares method to R = 4"5 % for 1323 observed reflexions. Each iron atom is complexed to a butadiene group of four planar carbon atoms of the ligand with the following C-C bond lengths, 1-413 (6), 1.401 (6), 1.422 (6) A,.161