At 298 K, pore-10 PLD has a distinct shoulder, indicating the presence of two states. One with a mean PLD of 2.4 Å and second with a mean PLD of 2.0 Å (Figure ). Snapshots of the pore corresponding to these two states reveal that the larger PLD is manifested when C=O swings out-ofplane of the pore (open state), while the smaller PLD occurs when they are in-plane (closed state, Figure ).