Influence of the Steric/Electronic Properties of N-Aryl Substituents in Cycloplatinated Guanidinate(1-) Complexes on the Formation of Discrete Pt → Ag Complexes and One-Dimensional Coordination Polymer

The reactions of cycloplatinated guanidinate(1-) complexes 1-6 with AgTFA (TFA = OC(O)CF3) in 1:1 and 1:2 PtII/AgI molar ratios afforded complexes containing three types of Pt2Ag2 skeletons (7-10, 11, and 13), one 1D CP containing Pt2Ag3 skeleton (16), and a Pt2Ag4 complex (17) in 91-95% (method 1), 73-82% (method 2) (7-10), and 54-79% (11, 13, 16, and 17) yields. The reactions of 11 with 2,6-XylNC (2,6-Xyl = 2,6-Me2C6H3) and 4-DMAP (4-dimethylaminopyridine) gave a neutral complex 18 and an ionic complex 19, respectively. Molecular structures of 12 complexes were unambiguously determined by single-crystal X-ray diffraction. Ten complexes contain unprecedented PtAg skeletons and are shown to contain multiple number of dative Pt-* Ag bonds supported by the TFA ligand, platinated carbon of the TAG ligand, or both these ligands in conjunction with the Ag-Ag contacts stabilized by argentophilic interaction. Further, the new complexes were characterized by analytical, IR, and multinuclear NMR (19F, 1H, 13C{1H}, and 195Pt) spectroscopies, powder X-ray diffraction, and TGA/DTA. In solution, 9 and 19 exist in more than one form as identified by multinuclear NMR, and this behavior is ascribed to the restricted (N2)C-N(H)Ar single-bond rotation of the TAG ligand. The photophysical properties of 9 and 11 are reported.

Automated summary

The reactions of cycloplatinated guanidinate(1-) complexes 1-6 with AgTFA (TFA = OC(O)CF3) in different molar ratios yielded complexes containing unique PtAg skeletons, which were characterized by various spectroscopic techniques and single-crystal X-ray diffraction. The presence of multiple dative Pt-* Ag bonds and argentophilic interactions stabilized the PtAg skeletons. The behavior of 9 and 19 in solution was attributed to the restricted rotation of the TAG ligand. The photophysical properties of 9 and 11 were also investigated.