Selective discrimination of putrescine and cadaverine based on a Fe³⁺-morpholinoanthracene ensemble in solution and solid state and logic gate aided biological applications in mixed aqueous medium

A 9,10-bis(morpholinopropylaminomethyl)anthracene (1)-Fe³⁺chelate was designed, synthesized, and characterized by FT-IR, ¹H-¹H COSY and ¹H-¹H ROESY NMR studies. The in situ-generated Fe³⁺ ensemble selectively detected putrescine (Put) and cadaverine (Cad) through a turn-off response via a decomplexation process in DMSO-H₂O (1:1 v/v) at pH 7.3 (HEPES buffer). Furthermore, the in situ-generated ensemble can effectively differentiate biogenic aliphatic di- and triamines from a broad range of aliphatic monoamines (including basic amino acids) and aromatic amines (including polyamines). The lowest limit of detection (LOD) for Put and Cad were 33 ppb and 120 ppb, respectively, in mixed aqueous medium. The decomplexation aided turn-off response by the sequential addition of Put and Cad furnished good association constants [K_sv = 2.30 × 10⁶ M⁻¹, and 9.95 × 10⁵ M⁻¹ in a HEPES-buffered DMSO-H₂O (1:1, v/v) medium, respectively]. Furthermore, highly robust vapor phase detections of Put and Cad were also demonstrated using the fluorescent 1·Fe³⁺ (1:2) ensemble coated on neutral alumina. Cheap ensemble-coated paper strips selectively detected Cad and Put among a variety of biogenic amines. By utilizing complexation/decomplexation processes aided through sequential addition of Fe³⁺ and Put/Cad an INHIBIT photonic logic gate and its fluorogenic tracking was demonstrated in primitive- eukaryotic cell lines.