Macrocyclic Platinum(II) Complexes with a Bifunctional Diphosphine Ligand

The preparation and coordination chemistry of a ditopic ligand scaffold ( 1 H2 ), containing both a phosphorus‐donor ( P ) and a nitrogen‐donor ( N ) binding pocket, is reported. The ligand was synthesized by reductive amination from 3‐(diphenylphosphino)benzaldehyde and N ‐(2‐aminophenyl)‐ N ‐methylbenzene‐1,2‐diamine. Selective coordination in the P ‐pocket was achieved for Pt II , with careful control over the reaction conditions and precursor materials providing access to either the thermodynamic cis isomer, cis ‐PtCl 2 ( 1 H2 ) ( 2 ), or the kinetic trans isomer, trans ‐PtCl 2 ( 1 H2 ) ( 3 ). Both species have been fully characterized both in the solid state and in solution. Thermodynamic parameters for isomerization processes of 2 and 3 have been determined. Halide abstraction from 2 and 3 led to formation of cis ‐[Pt(CH 3 CN)(Cl)( 1 H2 )]BF 4 and trans ‐[Pt(CH 3 CN)(Cl)( 1 H2 )]BF 4 .