Isomerization of a lanthanide complex using a humming top guest template: a solid-to-solid reactionElectronic supplementary information (ESI) available: Synthetic and crystallographic details for 1 and 2; Tables S1-S3. CCDC 1415404 & 1415405. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5ce01680k

SbPh 3 Cl 2 is used to effect a dramatic rearrangment of the ligand sphere and "pancake bonding" in Ce(hfac) 3 (5′-Br-pyDTDA) 2 , by forming a 2 : 1 host-guest complex supported by numerous non-covalent contacts (hfac = 1,1,1,5,5,5-hexafluoroacetylacetonato-; 5′-Br-pyDTDA = 4-(5′-bromopyrid-2′-yl)-1,2,3,5-dithiadiazolyl). The host-guest complex forms quantitatively in a solvent-free solid-to-solid reaction and crystals are grown by sublimation. SbPh 3 Cl 2 is used to effect a dramatic rearrangement of the ligand sphere and "pancake bonding" in Ce(hfac) 3 (5′-Br-pyDTDA) 2 by forming a 2 : 1 host-guest complex.