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

Abstract

The reactions of cycloplatinated guanidinate(1−) complexes 1−6 with AgTFA (TFA = OC(O)CF 3 ) in 1:1 and 1:2 Pt II /Ag I molar ratios afforded complexes containing three types of Pt 2 Ag 2 skeletons (7−10, 11, and 13), one 1D CP containing Pt 2 Ag 3 skeleton ( 16), and a Pt 2 Ag 4 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-Me 2 C 6 H 3 ) 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 ( 19 F, 1 H, 13 C{ 1 H}, and 195 Pt) 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 (N 2 )C−N(H)Ar single-bond rotation of the TAG ligand. The photophysical properties of 9 and 11 are reported.

Syntheses, structural, photophysical and theoretical studies of heteroleptic cycloplatinated guanidinate(1−) complexes bearing acetylacetonate and picolinate ancillary ligands

“…195 Pt NMR spectra of precursors 7–9 revealed a singlet at δ Pt −3606, −3591 and −3622, respectively. The aforementioned δ Pt values are somewhat comparable with those shifts reported for 1–5 ( δ Pt −3737 (1), 30 −3650 (2), −3674 (3), −3655 (4) 31 and −3717 (5) 32 ).…”

“…We believe that these two species arise due to the restricted rotation of the exocyclic (N 2 )C–N(H)Ar single bond in the six-membered [Pt(TAG)] ring. 32,37 …”