The cyanobis(1,10-phenanthroline)platinum(II) complex in aqueous solution and as the crystalline nitrate. Nuclear magnetic resonance measurements and crystal-structure determination

Abstract

The bis(1,10-phenanthroline)platinum(II) cation rapidly adds cyanide in aqueous solution forming the cyanobis-(1,10-phenanthroline)platinum(II) ion, which from ¹³C n.m.r. spectra has been shown to contain five-co-ordinated platinum both in water and in nitromethane solution. The crystals of cyanobis(1,10-phenanthroline)platinum(II) nitrate are triclinic, space group P, with Z= 2 and unit-cell dimensions a= 15.616(11), b= 7.264(6), c= 10.564(7)Å, α= 102.81(4), β= 80.90(4), and γ= 96.47(4)°. The structure has been determined by the heavy-atom method from diffractometer data and refined to R= 0.031 for 3 562 independent reflections. Three nitrogen atoms from the phenanthroline groups and the carbon atom from the cyanide form an approximately square-planar configuration about the platinum; Pt–N(1) 2.062(5), Pt–N(2) 2.007(5), Pt–N(3) 2.053(5), and Pt–C(25) 1.931(6)Å. The remaining nitrogen atom of the phenanthroline groups is at the apex of a square pyramid, Pt–N(4) 2.761 (5)Å. In aqueous solution OH^– and SH^– appear to react analogously with the bis(1,10-phenanthroline)-platinum(II) ion. The cyano-complex is stable in solution and reacts only slowly with other nucleophiles (e.g. excess of CN^–, OH^–, and halide ions).