Tetraphosphonate cavitands: interplay between metal coordination and H-bonding in the formation of dimeric capsulesElectronic supplementary information (ESI) available: ORTEP and stick views of the complexes, details of crystallographic data collection and crystallographic data. CCDC reference numbers 767369-767371. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c003426f

Three novel dimeric capsules formed by a tetraphosphonate cavitand with barium, calcium and zinc salts have been synthesized and structurally characterized. The role of cation dimensions and of coordinated water molecules in determining different architectures is also described. Three novel dimeric capsules formed by a tetraphosphonate cavitand with barium, calcium and zinc salts have been synthesized and structurally characterized.