A U-shaped Pt2Ag2 complex [Pt2Ag2(ppy)2(Ph2pz)4] with a pre-organized cavity (ppy = 2-phenylpridinate and Ph2pz = 3,5-diphenylpyrazolate) and related complexes have been prepared. The Pt2Ag2 complexes react with Ag(I) ions to give the corresponding Pt2Ag3 complexes containing Pt→Ag dative bonds. It became obvious that the existence of the C(ipso) atom in the chelate ligand is important as the driving force for forming Pt→Ag dative bonds. However, once the Pt2Ag3 complex is formed, the trapped Ag(I) ion is mainly stabilized by the Pt→Ag dative bonds, which are stronger than the Ag–C(ipso) bond. The trapped Ag(I) ion can be abstracted from the cavity selectively by adding an equivalent amount of chloride ion into the solution of Pt2Ag3 complexes to reproduce the original Pt2Ag2 complexes.

The reactions of monocationic Pt(II) complexes bearing N^C chelate ligands and Me2pzH, [Pt(N^C)(Me2pzH)2]PF6 (N^C = 2-phenylpyridinate (ppy−), 2-(2,4-difluorophenyl)pyridinate (dfppy−), benzo[h]quinolinate (bzq−); Me2pzH = 3,5-dimethylpyrazole), with Ag(I) ions gave Z (or U)-shaped neutral tetranuclear Pt2Ag2 complexes [Pt2Ag2(N^C)2(Me2pz)4], while those with Au(I) ions gave neutral trinuclear PtAu2 complexes [PtAu2(N^C)(Me2pz)3]. On the contrary, the reactions of the dicationic Pt(II) complex bearing a N^N chelate ligand and Me2pzH, [Pt(bpy)(Me2pzH)2](PF6)2 (bpy = 2,2′-bipyridine), with Ag(I) and Au(I) ions both gave Z (or U)-shaped dicationic tetranuclear Pt2M2 complexes, [Pt2M2(bpy)2(Me2pz)4](PF6)2 (M = Ag, Au). The structures of heteropolynuclear Pt(II) complexes were dominated by the nature of incorporated group 11 metal ions and the charge of complexes.

A series of imidoylamidinato Pt(II) complexes have been prepared by the reaction of [Pt(bpy)(RCN)2]2+ (R = Me, Et, Ph) generated in a nitrile solution with 1H-pyrazole-1-carboxamidine. These complexes exhibit bright yellow or yellow-green luminescence in the solid state and mechanochromic behavior.

Heteropolynuclear PtII complexes with 3,5-diphenylpyrazolate [Pt2Ag4(μ-Cl)2(μ-Ph2pz)6] (3), [Pt2Ag2Cl2(μ-Ph2pz)4(Ph2pzH)2] (4), [Pt2Cu2Cl2(μ-Ph2pz)4(Ph2pzH)2] (5), [Pt2Ag4(μ-Cl)(μ-Me2pz)(μ-Ph2pz)6] (7), and [Pt2Ag4(μ-Me2pz)2(μ-Ph2pz)6] (8) have been prepared and structurally characterized. These complexes are luminescent except for 5 in the solid state at an ambient temperature with emissions of red-orange (3), orange (4), yellow-orange (7), and green (8) light, respectively. Systematic red shift of the emission energies with the number of chloride ligands was observed for 3, 7, and 8. DFT calculations indicate that the highest occupied molecular orbital (HOMO) as well as HOMO-1 of the heterohexanuclear complexes, 3, 7, and 8, having Pt2Ag4 core, mainly consist of dδ orbital of PtII and π orbitals of Ph2pz ligands, while the lowest unoccupied molecular orbital (LUMO) of these complexes mainly consists of in-phase combination of 6p of two PtII centers and 5p of four AgI centers. It is likely that the emissions of 3, 7, and 8 are attributed to emissive states derived from the Pt2(d)/π → Pt2Ag4 transitions, the emission energy of which depends on the ratio of chloride ligands to pyrazolate ligands.

The platinum dimer and heteropolynuclear platinum complexes of 3,5-dimethylpyrazolate, [Pt2M4(μ-Me2pz)8] [M = H (1), Ag (2), Cu (3)], were synthesized and structurally characterized. They exhibit yellow, sky-blue, and orange luminescence, respectively, in the solid state. The absorption bands of 2 and 3 are mainly assigned to the combination of the metal–metal-to-ligand charge-transfer and [Pt2 → Pt2M4] transitions by the time-dependent density functional theory (DFT) method. DFT calculations also indicate that the emissive states of 2 and 3 are 3[Pt2 → Pt2Ag4] and 3[Cu(d) → Pt2Cu4], respectively.

A U-shaped Pt2Ag2 complex [Pt2Ag2(ppy)2(Ph2pz)4] with a pre-organized cavity (ppy = 2-phenylpridinate and Ph2pz = 3,5-diphenylpyrazolate) and related complexes have been prepared. The Pt2Ag2 complexes react with Ag(I) ions to give the corresponding Pt2Ag3 complexes containing Pt→Ag dative bonds. It became obvious that the existence of the C(ipso) atom in the chelate ligand is important as the driving force for forming Pt→Ag dative bonds. However, once the Pt2Ag3 complex is formed, the trapped Ag(I) ion is mainly stabilized by the Pt→Ag dative bonds, which are stronger than the Ag–C(ipso) bond. The trapped Ag(I) ion can be abstracted from the cavity selectively by adding an equivalent amount of chloride ion into the solution of Pt2Ag3 complexes to reproduce the original Pt2Ag2 complexes.

The reactions of monocationic Pt(II) complexes bearing N^C chelate ligands and Me2pzH, [Pt(N^C)(Me2pzH)2]PF6 (N^C = 2-phenylpyridinate (ppy−), 2-(2,4-difluorophenyl)pyridinate (dfppy−), benzo[h]quinolinate (bzq−); Me2pzH = 3,5-dimethylpyrazole), with Ag(I) ions gave Z (or U)-shaped neutral tetranuclear Pt2Ag2 complexes [Pt2Ag2(N^C)2(Me2pz)4], while those with Au(I) ions gave neutral trinuclear PtAu2 complexes [PtAu2(N^C)(Me2pz)3]. On the contrary, the reactions of the dicationic Pt(II) complex bearing a N^N chelate ligand and Me2pzH, [Pt(bpy)(Me2pzH)2](PF6)2 (bpy = 2,2′-bipyridine), with Ag(I) and Au(I) ions both gave Z (or U)-shaped dicationic tetranuclear Pt2M2 complexes, [Pt2M2(bpy)2(Me2pz)4](PF6)2 (M = Ag, Au). The structures of heteropolynuclear Pt(II) complexes were dominated by the nature of incorporated group 11 metal ions and the charge of complexes.