Metal–metal bonding in co-ordination complexes. Part IX. Crystal structure of trans-di-µ-carbonyl-dicarbonyldi-π-cyclopentadienyldi-iron (Fe–Fe), a redetermination

Abstract

The c rysta I st ru ct u re of the trans-isomer of d ip-car b o n y Id i c a r b o n y Id i -7 ~-c y cl o pe n t a d i e n y I d iiron has been redetermined by three-dimensional methods. The space group is P2Jc with a = 7.046(1), b = 12.453(2), c = 7.990(1) A, p = 108.44(1)", and Z = 2. The 904 reflections measured by counter diffractometry were used in the refinement by block-diagonal least-squares methods. With individual anisotropic thermal parameters and no allowance for hydrogen atom contributions, R = 0.044, WR = 0.056. Bond lengths and angles are : Fe-Fe 2.534(2) ; Fe-C(bridge) 1.91 0, 1.91 8(5) ; Fe-C(termina1) 1.748(6) ; Fe-C(ring) 2.082-2.1 21 (8) ; C-O(bridge) 1 .I 88(6) ; C-O(termina1) 1 .I 57(7) ; and C-C 1~346-1~405(11) A; and Fe-C(bridge)-Fe 82-9(2) ; C(bridge)-Fe-C(bridge) 97.1 (4) ; C(bridge)-Fe-C(termina1) 93.7(2) ; Fe-C-(bridge)-0 138.4-1 39.1 (3) ; and Fe-C(termina1)-0, 178-4(8)".The identity of the Fe-Fe distance in both cisand trans-isomers makes it unlikely that the former is stabilised preferentially by a 7 ~-or S-contribution to the metal-metal bond as has been suggested.

Disulfido iron–manganese carbonyl cluster complexes: Synthesis, structure, bonding and properties of the radical CpFeMn2(CO)7(μ3-S2)2

“…The Fe(2)-Fe(2 * ) distance is quite short and clearly indicative of an Fe-Fe bonding interaction. The Fe(2)-Fe(2 * ) distance of 2.545(1) Å and is very similar to the Fe-Fe distance in [CpFe(CO) 2 ] 2 , cis-isomer, 2.531(1) Å [10]; trans-isomer, 2.534(2) Å [11]. The S(2)-S(3) bond distance 2.0711 (14) Å is quite similar to the S-S bond distances observed in compounds 1 and 2.…”

“…The known compound [CpFe(CO) 2 ] 2 can subsequently be eluted from the baseline in approx. 20% yield by using pure CH 2 Cl 2 elution solvent [10,11].…”

Structure, Spectroscopy and Photochemistry of the [M(η5-C5H5)(CO)2]2 Complexes (M=Fe, Ru)

“…The X-ray and neutron diffraction studies [7][8][9] showed that I has a centrosymmetric structure in the solid phase with two bridging and two terminal carbonyl groups (trans-bridged form). Low-temperature crystallization made possible isolation of the cis form [10].…”

“…The first low energy band of [Re 2 (CO) 10 ] was suggested to overlap with the intense near-UV band [37]. For [Co 2 (CO) 8 ] two low energy bands at about 430 and 410 nm were ascribed to dAEs * transitions in the non-bridged and bridged isomers, respectively, and two higher energy bands at about 350 and 280 nm were ascribed to sAEs * transitions in non-bridged and bridged isomers, respectively [39].…”

Di-μ-carbonyl-dicarbonylbis[(2-hydroxyethyl)-η5-cyclopentadienyl]diiron(Fe-Fe)

“…The title compound is an intermediate in the synthesis of polymers with Fe Fe bonds in the backbone . The Fc Co--Fe bridge is slightly asymmetric compared with that in the parent trans-Fea(CO)a(CsHs)2 (Bryan & Greene, 1970), but other dimensions are not significantly affected. Intermolecular hydrogen bonds are also present in Mo2(CO)6(CsHaCH2CH2OH)2 (Tenhaeff, Tyler & Weakley, 1991).…”