[1] Univ Birmingham, Sch Chem, Mol Sci Bldg, Birmingham B15 2TT, England
[2] Francis Crick Inst, Artificial Mol Machinery Lab, London, England
[3] Kings Coll London, Dept Chem, London, England
[4] Univ Wurzburg, Inst Organ Chem, Wurzburg, Germany
[5] Univ Wurzburg, Ctr Nanosyst Chem CNC, Wurzburg, Germany
[6] Univ Siegen, Dept Chem & Biol, Siegen, Germany
[7] Univ Oxford, Dept Chem, Oxford, England
[8] Univ Leeds, Sch Chem, Leeds, England