Platinum(II) Bisisocyanide Cyclometallated Complexes: Synthesis, Structure, Photophysical Properties, and Mechanochromic Behavior

A series of platinum(II) cyclometallated complexes with two isocyanide ligands [Pt(ppy){CNAr}(2)]X (pp-2-phenylpyridine; Ar = C6H2-2,4,6-Me-3, C6H3-2-Cl-6-Me, C6H3-2,6-Cl-2, C6H4-4-NMe2, C6H4-4-Me, C6H4-4-Cl, C6H4-4-Br, C6H4-4-I, C6H4-4-CF3, C6H4-3-CF3; X = BF4, OTf) was synthesized by the reaction of [{Pt(ppy)Cl}(2)] dimer and a corresponding isocyanide (yields 52-70%). Their structure was determined by HR-EIMS, H-1, C-13{H-1}, Pt-195{H-1}, H-1,H-1-COSY, H-1, H-1-NOESY, H-1,C-13-HSQC, and H-1,C-13-HMBC NMR spectroscopy in solution and CP/MAS C-13 and Pt-195 NMR spectroscopy in solid-state, IR spectroscopy, and by X-ray diffraction analysis. The photophysical properties of the obtained complexes in the solid state and the mechanochromic luminescence behavior were studied. In the solid state, all synthesized compounds phosphoresce in the green or orange regions of visible spectrum with photoluminescence quantum yields reaching 26%. The green phosphors exhibit a reversible mechanochromic luminescence changes (green to orange) under mechanical grinding and (orange to green) upon solvent adsorption.

Automated summary

A series of platinum(II) cyclometallated complexes with two isocyanide ligands were synthesized and characterized. Their structure was determined by various spectroscopic techniques and their photophysical properties and mechanochromic luminescence behavior were studied in the solid state.