Rational Design of an Amphiphilic Coordination Cage-based Emulsifier.

Self-assembled, porous coordination cages with a functional interior find application in controlled guest inclu-sion/release, drug delivery, separation processes, and catalysis. However, only few studies exist that describe their utilization for the development of self-assembled materials based on their 3-dimensional shape and external functional-ization. Here, dodecyl chain-containing, acridone-based ligands (LA) and shape-complementary phenanthrene-derived ligands (LB) are shown to self-assemble to heteroleptic coordination cages cis-[Pd2(LA)2(LB)2]4+ acting as a gemini amphiphile (CGA-1; Cage-based Gemini Amphiphile-1). Owing to their anisotropic decoration with short polar and long non-polar side chains, the cationic cages were found to assemble into vesicles with diameters larger than 100 nm in suitable polar solvents, visualized by cryo-TEM and Liquid-Cell Transmission Electron Microscopy (LC-TEM). LC-TEM reveals that these vesicles aggregate into chains and necklaces via long-range interac-tions. In addition, the cages show a rarely described ability to stabilize oil-in-oil emulsions.