Synthesis and characterization of Pt(II) and Pd(II) PTA and DAPTA complexes

A series of four-coordinate air stable and water soluble cis- and trans-Pt(II) and Pd(II) complexes containing two PTA or DAPTA ligands (PTA = 1,3,5-triaza-7-phosphaadamantane; DAPTA = 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) with the general formulas, [PtR2(PTA)2], [M(Me)X(PTA)2], [Pt(Et)X(PTA)2], [MR2(DAPTA)2], [MX2(DAPTA)2], and [M(Me)X(DAPTA)2] (where M = Pt or Pd; R = Me, Et, CCR (R = Ph, SiMe3); X = Cl, Br, I) were prepared by ligand displacement starting from [M(R)2(COD)], [M(R)(X)(COD)] or precursors or metathesis reactions utilizing [MCl2(PR3)2] precursors in good yields (63%–90%). The complexes were characterized by multinuclear NMR, IR, MS, and elemental analysis experiments and in some cases by X-ray crystallography studies. Complexes, cis-[PtMe2(PTA)2] (cis-1), trans-[Pt(Me)Cl(PTA)2] (trans-3a), trans-[PtCl2(PTA)2] (trans-4), trans-[Pt(CCPh)2(PTA)2] (trans-6), and trans-[PtI2(DAPTA)2] (trans-13c) were characterized by X-ray crystallography. The molecular structures reveal, in general, distorted square planar geometries at the metal center. For the DAPTA complexes, both syn- and anti-conformations of the DAPTA rings were observed depending upon the nature of the groups at the metal center.

Graphical abstractSquare planar Pt(II) and Pd(II) complexes containing the water soluble phosphane ligands, PTA and DAPTA (PTA = 1,3,5-triaza-7-phosphaadamantane; DAPTA = 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) were synthesized and characterized. Several of the complexes were characterized by single-crystal X-ray diffraction.Figure optionsDownload full-size imageDownload as PowerPoint slide