Phosphorescent PtII Systems Featuring Both 2,2′-Dipyridylamine and 1,3,5-Triazapentadiene Ligands

The treatment of cis‐[Pt(dpa)(RCN)2][SO3CF3]2 {dpa = 2,2′‐dipyridylamine, R = Me, Et, CH2Ph, Ph; [2a–d](OTf)2} (OTf = SO3CF3) with 2 equiv. of N,N′‐diphenylguanidine [NH=C(NHPh)2] in CH2Cl2 solutions at room temp. for 16 h gives [Pt(dpa){NH=C(R)NC(NHPh)=NPh}][SO3CF3] {[3a,b,d](OTf)} as the addition products and [Pt(dpa){NH=C(R)NHC(R)=NH}][SO3CF3]2 {[4a,b](OTf)2} as the tailoring products. The formulation of complexes [3a,b,d](OTf) and [4a,b](OTf)2 was supported by satisfactory C, H, and N elemental analyses and agreeable high‐resolution ESI‐MS, IR, and 1H (including 1H–1H COSY experiments) and 13C{1H} NMR data. The structures of all of the platinum species were determined by single‐crystal X‐ray diffraction. The resultant complexes are nonemissive in solution, mainly because of the interaction between the empty d z 2 orbital in a square‐planar configuration and solvent molecules. However, in the solid state, complexes [3a,b,d](OTf) exhibit strong phosphorescence with quantum yields (peak wavelength) of 0.23 (490 nm), 0.27 (483 nm), and 0.20 (532 nm), respectively. The interplay between N,N′‐diphenylguanidine and cis‐(dpa)(RCN)2PtII species (dpa = 2,2′‐dipyridylamine) gives both the so‐called tailoring products and the addition products. The latter exhibit intense luminescence in the solid state.