A New Type of Terpene-Based D2-Symmetric Macrocycles, Capable of Selectively Extracting Au, Pd and Pt from Complex Mixtures

摘要

C2-symmetric terpene-based bis(α-amine oximes) prepared from monoterpene hydrocarbons (+)-3-carene, (-)-α-pinene and (+)-limonene, when treated with methylene chloride under phase-transfer conditions, undergo inter- and intramolecular cross-linking at oxime groups to form D2-symmetric macro-cycles in relatively good preparative yields (35-64%). The structure of the new compounds was solved by spectroscopic methods and proved by X-ray crystallography. D2-symmetric macrocycles are crystalline solids which are well soluble even in small amounts of low-polar organic solvents. Using Microwave Plasma Atomic Emission Spectrometry the new compounds was found to be able to selectively extract some noble metals (Pt~(IV), Au~(III), Pd~(II)) from aqueous solutions with pH=1.2 containing complex mixtures of transition elements at with no noticeable extraction of d-elements (Cr~(VI), Mn~(II), Fe~(III), Co~(II), Ni~(II), Cu~(II), Zn~(II)) and other noble metals (Ru~(III), Rh~(III), Ir~(III)).