Optical sensing of aqueous nitrate anion by a platinum(II) triimine salt based solid state material.

Selective and quantitative measurement of aqueous nitrate (NO3-) anion is achieved using solid [Pt(Cl-4-tpy)Cl]ClO4 salt (Cl-4-tpy = 4-chloro-2,2':6'2''-terpyridine), and as the salt supported on controlled porous glass. This detection method relies on the color change of the Pt(II) complex from yellow to red and intense luminescence response upon ClO4- exchange with NO3- due to concomitant enhancement of Pt⋯Pt interactions. The spectroscopic response is highly selective for NO3- over a large range of halides and oxoanions.