To investigate the stability of the hexagonally packed TMA structures (TMA_2-33, 3-31, 3-36, 7-35, 8-32, and 8- 35) in the absence of the crystallization solvent, we exchanged the solvent in the pores with the n-pentane and then activated the crystals by evacuating at room temperature for 2 hours. PXRD analysis showed that all six of the resulting n-pentane solvates transformed to the same phase after activation.