Developing the spectral sensing scheme with in situ generated chromophores

The classic spectral molecular sensor consists of a binding site linked to a chromophore via a conjugate or nonconjugate spacer, thus a spectral background may exist. It is therefore demanded to have a spectral sensing scheme with in situ formed chromophore when the sensing species is present with the sensory molecule that the spectral sensing is in principle background free. Metal cations of d⁸ or d¹⁰ electronic configuration when brought into close proximity would facilitate the metallophilic interaction, exhibiting characteristic spectral signals from the chromophore in situ generated upon the occurrence of metal … metal interaction. This Review discusses four spectral sensing platforms with chromophores in situ generated, i.e., the homoatomic metallophilic complexes such as multinuclear Au⁺ complexes, cofacial stacking of Pt²⁺ ensembles, Ag⁺-thiol coordination polymers, and heterometallic complexes. These sensing platforms represent a new scheme that relies on the signalling chromophore in situ generated only when the sensing species is present.