Structure of tricarbonyl-(η4-1,4-dibenzoyloxy-1,3-butadiene)iron(0)

Abstract

Fe(CO)3(CI8H1404)l , Mr=434.2 , mono- clinic, P2Jc, a=6.152(2), b=32.318(10), c= 10.210 (4)A, fl= 104.26 (3) ° , V= 1967 (1)/~3, Z= 4, Dx=l.47Mgm -3, 2(MoKt~)=0.7107A , g= 0.802 mm -~, F(000) = 888, T= 293 K, R = 0.048 for 2681 observed reflections. The X-ray study confirms that the solid-state structure of tricarbonyl(r/4-1,4 - dibenzoyloxy-l,3-butadiene)iron(0) is as inferred from spectroscopic evidence. The molecule contains a diphenylester-vinyl unit bonded to the iron atom, to which are also bonded three carbonyl groups in an approximately trigonal arrangement. Both ~COO- ester groups are planar and synclinal to each other about the central C(5)-C(6) bond. There is only one C--H...O intermolecular approach <3.3 A. The crystal structure is stabilized by van der Waals forces. Introduction. As part of our investigations concerning complexes between Fe(CO)3 and vinyl ligands with various substituents, including phenyls, esters and acyl groups, the title compound (2) was synthesized. It was obtained from the reaction of tricarbonyl(q4-syn-l,4 - diacetoxy-l,3-butadiene)iron(0) (1) (170 mg, 1 mmol) and MeLi (6.2 ml, 0.8 M) with 15 ml of anhydrous tetrahydrofuran (THF) at 195 K in an argon at- mosphere, to give a red solution. After 10 min of stirring, benzoic anhydride (1.13 g, 5 mmol) in 5 ml of