Abstract
The substitution reactions of [Re(CO)~5~X] (X = Cl, Br) with 2,6‐dihalo‐substituted nitrosobenzene derivatives C~6~H~2~YZ~2~NO (Y = H, Cl, Br; Z = Cl, Br) leads to the formation of dinuclear μ~2~‐η^2^‐N,O‐nitrosobenzene‐bridged complexes of the type [{(CO)~3~Re(μ‐X)}~2~ONC~6~H~2~YZ~2~] (6a,b, 7a,b, 8a,b, 9a). The turquoise coloured solutions of the complexes in CH~2~Cl~2~ show only one UV/Vis absorption of medium intensity in the region 670–710 nm, depending on the halogen bridges X and substituents Z. Single crystals of the complexes do not exhibit any dichroic properties. This may be due to the almost perpendicular orientation of the phenyl ring towards the Re–O–N–Re plane. The molecular structures of six compounds, as determined by single‐crystal X‐ray analyses, show two face‐joined octahedra with Re centres that are bridged by two halogens X and one NO group. NO coordinates in a nonsymmetrical η^2^‐like fashion with N‐ or O‐linkage to each Re centre. The phenyl rings do not lie within the symmetry plane containing the atoms Re, N and O, but are almost perpendicular to this (torsion angle O–N–C–C = 83.5–85.4°) because of the 2,6‐dihalogen substituents Z. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)