A cobalt(II) complex with unique paraSHIFT responses to anions

ParaSHIFT agents have shown promise in detecting chemical targets in biological systems by magnetic resonance, but few studies have used transition metal complexes for this purpose. Here we report our investigations into CoMe₆trenCl (tren = tris(2-aminoethyl)amine) as a paraSHIFT agent. The paramagnetic region of the ¹H NMR spectrum shows characteristic spectral profiles in the presence of fluoride, acetate, lactate and citrate in aqueous solution. These distinctive NMR shifts of each anion are maintained even in mixtures of anions.