Metal–carbonyl and metal–nitrosyl complexes. Part XV. Crystal and molecular structure of (3-formyl-N-ethoxycarbonylazepine)tricarbonyliron(0)

Abstract

The molecular geometry of the title compound has been determined by single-crystal X-ray analysis from diffractometer data; the positional and thermal parameters of the atoms were obtained by Fourier and least-squares procedures and the final value of R was 4·6% over 2363 independent reflections. The tricarbonyliron group binds to the C(4), C(5), C(6), C(7)-butadiene fragment of the azepine ring, with Fe–C(4), C(7) distances of 2·151 and 2·096(4)Å and Fe–C(5), C(6) distances of 2·053 and 2·051(4)Å. The bond lengths in the azepine ring are: N(1)–C(2) 1·379, C(2)–C(3) 1·347, C(3)–C(4) 1·465, C(4)–C(5) 1·431, C(5)–C(6) 1·406, C(6)–C(7) 1·431, and C(7)–N(1) 1·447 Å, all with σca. 0·005 Å. The ring has two nearly planar groups of atoms, (i) C(4), C(5), C(6), C(7), and (ii) C(7), N(1), C(2), C(3), C(4), the dihedral angle between the planes being 138°. The crystals are triclinic, space group P, with a= 7·022(3), b= 10·550(4), c= 9·500(3)Å, α= 92° 49(2)′, β= 94° 32(2)′, γ= 96° 8(2)′, and Z= 2.