Novel Luminescent homo/heterometallic platinum(II) alkynyl complexes based on a Y-shaped pyridyl diphosphine
A series of dinuclear platinum(II) alkynyl complexes [Pt2L2(C≡CC6H4R-4)4] (R=H 1, CH3 2, But 3), and unusual tetranuclear Pt(II)–Ag(I) clusters [Pt2Ag2L(C≡CC6H4R-4)6] (R=H, 4; CH3, 5; But, 6), together with novel polymer crystals [Pt2Ag2L(C≡CC6H5)6]∞ (∞), were synthesized by the self-assembly reaction between [NBu4]2[Pt(C≡CC6H4-R-4)4] and [Ag6L6]6+（L = 4-(3,5-(diphenylphosphine)phenyl)pyridine). These complexes were characterized by using a range of spectroscopic and X-ray crystallography for complexes 1, 3, 5, and ∞. Each platinum atom of the Pt(II)–Ag(I) clusters exhibits an unusual asymmetric distorted square planar geometry with three alkynyl groups and one bridging L phosphous atom. Dinuclear complexes 1-3 demonstrate solid-state weak blue luminescence, while tetranuclear Pt(II)–Ag(I) clusters 4-6 show intense blue-green or yellow-green emission. Furthermore, crystalline samples of the polymer ∞ display a bright yellow emission (518 nm) that is significantly red-shifted as compared to monomer crystal 4.