A facile synthesis of ferrocene functionalized vinyl ethers and their application as optical sensors for Cu2+ ions detection

Abstract

In this note, facile synthesis of ferrocenyl vinyl ethers has been reported through a NaOHassisted CO bond-forming reaction of various primary alcohol and ferrocene chlorovinyl derivatives. The presented method is high yielding and delivers the products substantially in a quite instant time. Functionalised ferrocenyl chlorovinyl derivatives (CHO, CN and C(CN)2) were found to be well tolerated for a wide range of primary alcohols. All the ferrocenated vinyl ethers are novel and not reported earlier. The vinyl ether derivatives formed through the reactions of 1,2- and 1,3-diols were tested for the optical metal sensing capabilities, and selectivity was observed for Cu2+ ions. The ferrocenated malenonitrile contaning vinyl ether showed a high sensitivity and selectivity towards Cu2+ among all the other tested metal ions. Upon interaction with Cu2+, the yellow color of this vinyl ether change into colourless and make the naked eye detection of Cu2+ ion under mild condition and very low concentrations. The receptor (vinyl ether) was created with a detection limit of 8.18 µM, for the highly selective, specific, and sensitive detection of Cu2+. To improve the applicability of this sensing system for onsite quantitation, TLC silica strips soaked in the compound solution was performed. Moreover, the application was further extended by incorporating mobile phone-based sensing studies.