Functionalized Platinum(II) Terpyridyl Alkynyl Complexes as Colorimetric and Luminescence pH Sensors

A series of platinum(II) terpyridyl alkynyl complexes that have been derivatized with basic amino functionalities,
[Pt(tpy)(C⋮C−C6H4−NR2-4]X (X = OTf-, R = CH3 1, R = CH2CH2OCH3 2, R = H 3; X = Cl-, R = CH3 4,
R = CH2CH2OCH3 5, R = H 6) (tpy = 2,2‘:6‘,2‘ ‘-terpyridine), have been synthesized and characterized. Their
photophysical responses at various acid concentrations were studied. The abilities of the complexes to function as
colorimetric and luminescence pH sensors were demonstrated with dramatic color changes and luminescence
enhancement upon introduction of acid.