35797-28-5Relevant articles and documents
Reaction of [Fe3(CO)12] with dicyclohexylcarbodiimide. Formation and structure of [Fe2(CO)6{μ,μ′-(C6H 11N)2CFe(CO)4}]
Doherty, John,Manning,Stephens
, p. 3332 - 3335 (2008/10/08)
The reaction of the carbodiimide C6H11NCNC6H11 (C6H11 = cyclohexyl) with [Fe2(CO)9] in boiling hexane gives the same products as it does with [Fe(CO)5], i.e., [Fe(CO)4(CNC6H11)] (I) and [Fe2(CO)6{μ,μ′-(C6H 11N)2CNC6H11}] (II), but with [Fe3(CO)12] in boiling heptane it also gives the previously unknown derivative [Fe2(CO)6{μ,μ′-(C6H 11N)2CFe(CO)4}] (III). The molecular structure of III has been determined by a single-crystal X-ray diffraction study. This shows that the Fe2(CO)6 fragment has the familiar saw horse structure with each of the two N atoms of the coordinated carbodiimide molecule bridging its two iron atoms and the carbodiimide carbon atom acting as an axial carbene ligand to a distorted trigonal-bipyramidal Fe(CO)4 moiety. The structure was solved by the heavy-atom method and refined by least squares to R = 0.074 for 1559 nonzero unique photographic reflections. Crystals of the compound are monoclinic, space group P21/n, with a = 10.876 (4) A?, b = 16.609 (7) A?, c = 14.982 (5) A?, and β = 90.7 (1)° for Z = 4. The IR spectrum of III is consistent with the presence of two isomers in solution arising from restricted rotation of the Fe(CO)4 moiety about the Fe-C(carbene) bond. The X-ray structure determination shows that this behavior is probably due to steric interactions between the Fe(CO)4 carbonyl ligands and the cyclohexyl groups. Although i-PrNCN-i-Pr reacts similarly with [Fe3(CO)12] to give products analogous to I, II, and III, with the last again exhibiting rotational isomerism, p-MeC6H4NCN-p-MeC6H4 forms counterparts of I and II but not III.
