Rhenium nitrosyl complexes with simple and with sterically demanding aromatic thiolate ligands: X-ray crystal structures of [PPh4][Re2(SC6H4Me-4)7(NO)2]·CH2Cl2 and [Re(SC6H3Pri2-2,6)4(NO)]

Abstract

Reaction of [ReCl₂(OMe)(NO)(PPh₃)₂] with a range of thiophenols under basic conditions gives one of two classes of products depending on the steric requirements of the thiols. A representative member of each class has been characterised by an X- ray crystal structure determination. Thiophenols with methyl or isopropyl groups in their ortho positions give the mononuclear complexes [Re(SR)₄(NO)](SR = SC₆H₂Prⁱ₃-2,4,6, SC₆H₃Prⁱ₂-2,6, SC₆H₂Prⁱ₂-2,6-4- Br, or SC₆H₂Me₃-2,4,6) which are trigonal bipyramidal with an axial NO group. Thiophenols without ortho-substituents give the dinuclear anions [Re₂(SR)₇(NO)₂]^–(SR = SPh or SC₆H₄Me-4) which contain a triple thiolate bridge between two equivalent rhenium atoms. These anions show a fluxionality involving intramolecular exchange of six thiolato-ligands.