The photocatalytic activity of TBAP-α was also investigated over a longer-term experiment and a slow loss of activity was observed over time (Figure ); the rate reduced to 653 µmol g - 1 h -1 after 20 hours, to 369 µmol g -1 h -1 after 60 hours and 156 µmol g -1 h -1 after 110 hours of photolysis. While this points to long-term instability, the sustained photochemical production of hydrogen at these rates over 110 hours is remarkable when one considers that TBAP-α is a molecular HOF where the framework is held together by hydrogen bonds and van der Waals interactions, which are weak in comparison to bonded frameworks such as CMPs and COFs.