Highly selective and discriminative detection of small alcohols based on a dual-emission macrocyclic samarium complex

Lower alcohols (C1-C7) have a close relationship with our lives and some of them are harmful to our body's health. For example, liquor mixed with a tiny amount of methanol is harmful to our health. Much of this study is about identifying one or two low-level alcohols. How to detect low-level alcohol and high-throughput and distinguish between analogues of alcohol remains a tremendous challenge. In this study, a new large ring Schiff base Sm(III) complex (Sm-2r) is synthesized with a double emission matrix using the template method. Its dynamic imine bond (CN) and organic ligands (H₂L2_r) with molecular rotor properties can respond to changes in viscosity and polarity in external environments. The PCA method is used to turn the data matrix into a fingerprint spectrum to distinguish different alcohols (C1-C7). Sm-2r enables the quantization of cyclopropyl and glycerol. Linear ranges of cyclopropanol and glycerol are 0-9.0% and 0-3.0% (v/v), respectively. In addition, Sm-2r has an excellent ability to distinguish the mixtures of n-PrOH and i-PrOH, C₅H₉OH and C₆H₁₁OH, n-PeOH and n-HeOH, 1,3-PDO and 1,2-PDO, MeOH and EtOH, 1,2-EG and 1,2-PDO at different volume ratios. We have provided a way to distinguish alcohol species based on their molecular polarity and viscosity.