complexes with halogens Summary [Fe2(q-Cp)2(CNAr)4 ] (2) (CNAr=Ph, C6H4Me-2, C6H4Et-2, C6H3Me2-2,4, C6HaMe2-2,6, C6H3(Me)Et-2,6, C6H3Et2-2,6 or C6H3i-Pr2-2,6 ) react with I2 to give [Fe(q-Cp)(CNAr)2I], but with Br 2 [Fe(q-Cp) (CNAr)3 ] + salts are the only products; IBr gives a mixture of the two.
With SnX2 (X = F, CI, Br or I) in refluxing n-butanol, (2)
gives isolable [{Fe0/-Cp)(CNAr)z}2SnXz] only when the CNAr ligands have two ortho substituents, otherwise decomposition occurred. When X = F, [Fe(q-Cp) (CNAr)zSnF3] was also obtained from this reaction. Attempts to prepare [Fe(q-Cp)(CNAr)2X ] (X = C1 or Br) by reaction of (2) with HX in the presence of air gave rather unstable products which with SnX z formed [Fe(q-CsHs)-(CNAr)2SnX3]. Similar compounds, [Fe(q-Cp) (CNAr) 2 SnX2I], were obtained from [Fe(q-Cp)-(CNAr)2I] and SnX 2 (X = C1 or Br but not I). All of these complexes are much less stable than their Fe(q-Cp)(CO) 2 counterparts; all decompose in solution to [Fe(r/-Cp)(CNAr)3] + which then break down to unidentified species. X-ray diffraction studies show that in [Fe(q-Cp)(CNC6H3i-Pr2-2,6)2I ] and [{Fe(q-Cp)(CNC6H3Me2-2,6)z}2SnBr2] there is pseudo-octahedral coordination about Fe. In the latter there is also distorted tetrahedral coordination about Sn so that its structure is very similar to that of [{Fe(q-Cp)(CO)2}zSnCI2]. Spectroscopic studies show that in all complexes rotation of the aryl rings of the CNAr ligands cannot be slowed in solution, and that there is free rotation about all Fe--Sn bonds.