Energy dispersive X-ray spectroscopy (EDS) indicated a M:Zr ratio of 1:1 (where M = Na + or K + ) for MOFs including SU-103 and SU-105 (see Supplementary Table ), whereas SU-107 and SU-102 showed a M:Zr ratio closer to 2:1. It is noteworthy that in the case of SU-104, SU-109 and SU-110, ion exchange was incomplete as indicated by very low M:Zr ratio, which is attributed to the more hydrophobic character of the trialkylammonium OSDAs (trihexylammonium, tributylammonium, and trioctylammonium respectively). In an attempt to promote a higher degree of ion exchange, these experiments were repeated for SU-104, SU-109 and SU-110 at 80˚C instead. Only SU-109, with trialkylammonium as the OSDA and the shortest alkyl chains amongst the tertiary ammonium cations, showed an increase in the M:Zr ratio at higher temperatures which approached 2:1 (Supplementary Table ). Higher temperatures or the use of less polar solvents or cations may be required to promote ion exchange to replace the more hydrophobic OSDAs such as trihexylammonium or trioctylammonium. Noticeably, the crystals of SU-104, SU-109 and SU-110 exhibited distinctly hydrophobic behavior during ion exchange attempts compared to the other MOFs. Only these hydrophobic crystals floated to the top of the aqueous salt solution when stirred and problematically stuck to the upper walls of the glass vials above the level of the solution. It appears as the hydrophobicity of the ammonium cations is translated to the MOF crystals. PXRD indicates that hydrophobic SU-104, SU-109 and SU-110 were highly stable and largely unaffected by the attempted ion exchange experiments.