Highly Selective Colorimetric and Luminescence Response of a Square-Planar Platinum(II) Terpyridyl Complex to Aqueous TcO sub(4) super(-)

Molecular recognition of an aqueous pertechnetate (TcO sub(4) super(-)) anion is fundamentally challenging partly due to the charge-diffuse nature of this anion, which hampers design of new technologies for its separation and detection. To address this gap, simple salts of transition metal complexes that undergo a distinct spectroscopic change upon exposure to aqueous anions were explored. The Pt(II) complex [Pt(tpy)Br]SbF sub(6) (tpy = 2,2'; 6',2"-terpyridine) undergoes a dramatic color change and intense luminescence response upon TcO sub(4) super(-) uptake due to concomitant enhancement of Pt times times times Pt interactions. The spectroscopic response was highly selective and quantitative for aqueous TcO sub(4) super(-) among other competing anions. Complementary Raman spectroscopy and microscopy techniques, structural determination, and theoretical methods were employed to elucidate the mechanism of this response at the molecular level.