Pt_2Ag acetylide-doped silica nanoparticles: enabling luminescence of Pt_2Ag complexes in water and sensors for highly sensitive detection of cyanide anions

摘要

Two novel luminescent hetero-trinuclear complexes Pt_2Ag(μ-dpppy)_2(CuCC_6H_4R-4)4(ClO_4) (R = H, 1; R = CH_3, 2; dpppy = 2,6-bis(diphenylphosphino)pyridine) were synthesized by the self-assembly reaction between Pt(CuCC_6H_4R-4)_4~(2-)and Ag_2(μ-dpppy)_3~(2+) and characterized by elemental analyses, electrospray ionization mass spectrometry, and ~1H NMR and ~(31)P{~1H} NMR spectroscopy and by X-ray crystallography for complex 2. Two Pt_2Ag complexes show strong luminescence in the solid state, but exhibit weak emission in CH_2Cl_2 solution and in acetonitrile-water (1: 1, v: v) solution at room temperature. To overcome the limitations of low water solubility and weak emission in solutions, a new kind of luminescent Pt_2Ag@SiO_2 nanoparticles was prepared by incorporating the new Pt_2Ag acetylides into monodisperse silica nanoparticles. It is noted that Pt_2Ag@SiO_2 nanoparticles exhibit strong luminescence in aqueous solution, and cyanide anions tend to decrease their luminescence intensity in NaHCO_3-NaOH buffer solution. Based on this, a novel nanosensor for highly sensitive detection of cyanide anions was developed in the range of 0.1-10.0 μM.