Metal-based surface active ionic liquids: Self-assembling characteristics and C[sbnd]C bond functionalization of tertiary amines with TMSCN in aqueous micellar solutions

Abstract

Metal-based surface active ionic liquids (MSAILs), 1-alkyl-3-methyl imidazoliumtetrachloromanganate [Cnmim][MnCl4]2− (n= 8,10,12) have been synthesized and characterized for self-assembling behavior in aqueous solution using tensiometry, fluorescence, conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) techniques. MSAILs have exhibited 4 to 5 fold higher surface activity as compared to the non-metal based surface active ionic liquids. MSAILs micellar solutions have been successfully used for C(sp3)-H functionalized oxidative cyanation of the tertiary amines. Oxidative Strecker reaction was carried out with different concentrations of the MSAILs, cyanide source (TMSCN) and substrate, and moderate to very high yields (up to 95%) could be achieved in 3–4 h. Usually, cyanation of tertiary amines is carried out in organic solvents under harsh conditions without recycling of the catalyst. Herein aqueous MSAILs micellar solutions have been used as a solvent, catalyst as well as template with a good recycling ability, thus making the approach simpler, greener, and sustainable.