Synthesis, crystal structures and properties of cis- and trans-isomers of [Pt{C6H4-4R1-1-[C8H4N-3′-NOMe]}Cl2(dmso)] (R1 = H or Cl)

The study of the reactivity of the 3-methoxyimino-2-phenyl-3H-indoles C6H4-4R1-1-[C8H4N-3′-NOMe] [R1 = Cl (1a) or H (1b)] with cis-[PtCl2(dmso)2] has allowed the isolation of trans-[Pt{C6H4-4R1-1-[C8H4N-3′-NOMe]}Cl2(dmso)] [R1 = Cl (2a) or H (2b)] and cis-[Pt{C6H4-4R1-1-[C8H4N-3′-NOMe]}Cl2(dmso)]·CH2Cl2 [R1 = Cl (3a) or H (3b)]. Their crystal structures confirm: (a) the existence of a PtNindole bond, (b) the relative arrangement of the Cl− ligands (trans in 2a and 2b or cis in 3a and 3b) and (c) the anti- (E) configuration of the oxime. A comparative study of the spectroscopic and photo-optical properties of ligands and their platinum(II) complexes (2a, 2b, 3a and 3b) is also reported.

► Cis- and trans-isomers of [PtCl2(dmso)(L1)] (L1 = polyfunctional 3-methoxyimino-2-phenyl-3H-indoles). ► The effect induced by the relative disposition of the Cl– ligands on the properties the Pt(II) complexes. ► The key role of the dmso ligand and its location on the crystal architecture. ► CH2Cl2 solvation molecules determining the dimensionality of the crystal.