Acyclic Diaminocarbene Platinum(IV) Complexes Synthesized by the Oxidative Addition of MeI and I2

Abstract

The oxidative addition of methyl iodide or molecular iodine to the bis(С,N-chelate) deprotonated diaminocarbene platinum(II) complexes [Pt{C(N(H)Ar)(NC(N(H)Ph)N(Ph)}₂] (Ar = C₆H₃-2,6-Me₂ (Xyl), C₆H₂-2,4,6-Me₃ (Mes), and C₆H₄-4-Me (pTol)) affords the corresponding platinum(IV) derivatives in a yield of 89–99%. The addition of CF₃CO₂H is accompanied by the protonation of the nitrogen atoms of the diaminocarbene fragment to form the cationic complexes [PtI(X)-{C(N(H)Ar)(NC-(N(H)Ph)N(Ph)}₂]CF₃CO₂H (X = Me, I). The structures of the compounds are determined by elemental analysis; high resolution mass spectrometry with electrospray ionization (ESI HRMS); IR spectroscopy; ¹H, ¹³C{¹H}, ¹⁹F{¹H}, and ¹⁹⁵Pt{¹H} NMR spectroscopy; 2D NMR spectroscopy (¹H,¹Н COSY, ¹H,¹Н NOESY, ¹H,¹³C HSQC, ¹H,¹³C HMBC, ¹H,¹⁵N HSQC, ¹H,¹⁵N HMBC), and X-ray diffraction (XRD) and thermogravimetric analyses. The synthesized platinum(IV) complexes are thermally stable to 200–260°C and are electroneutral molecules with the octahedral coordination sphere formed by two deprotonated diaminocarbene C,N‑chelate substituents and iodine and methyl or two iodine atoms localized in the apical positions.