Dynamic chemical devices: Photoinduced electron transfer and its ion-triggered switching in nanomechanical butterfly-type bis(porphyrin)terpyridines - Linke-Schaetzel, M; Anson, CE; Powell, AK; Buth, G; Palomares, E; Durrant, JD; Balaban, TS; Lehn, JM (CHEMISTRY-A EUROPEAN JOURNAL, 2006)