916853-01-5Relevant academic research and scientific papers
Absence of dichroism in dinuclear rhenium complexes with sterically hindered μ2-(η2-N,O)-nitrosobenze ligands
Krinninger, Christoph,Wirth, Stefan,Kluefers, Peter,Mayer, Peter,Lorenz, Ingo Peter
, p. 1060 - 1066 (2007/10/03)
The substitution reactions of [Re(CO)5X] (X = Cl, Br) with 2,6-dihalo-substituted nitrosobenzene derivatives C6H 2YZ2NO (Y = H, Cl, Br; Z = Cl, Br) leads to the formation of dinuclear μ2-η2-N,O-nitrosobenzene-bridged complexes of the type [{(CO)3Re(μ-X)}2ONC 6H2YZ2] (6a,b, 7a,b, 8a,b, 9a). The turquoise coloured solutions of the complexes in CH2Cl2 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 η2-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, 2006.
