Fig. 4: Structural transformation of Gd-B samples at ambient condition.
From: Combustible ice mimicking behavior of hydrogen-bonded organic framework at ambient condition
a–c Fresh Gd-B (a) loses accommodated MeOH (blue balls) molecules (b) upon exposure in air atmosphere, prolonged exposure results in the hydrolysis of borate ester anion of [B(OCH3)4]− by moisture, which further releases twelve MeOH molecules and turns into white powder (c, named as air-dried Gd-B). Grayish blue, light gray, pink, gray, and pale blue balls denote N, H, O, C, and B atoms, respectively. The dashed yellow lines denote the H-bond linking. d Crystal structure of [C(NH2)3]2[B4O5(OH)4]•2H2O. Two paths are available for the structural restoration of Gd-B. Typically, air-dried Gd-B is exposed in MeOH liquid or vapor to obtain Gd-B (path 1); air-dried Gd-B is dissolved in H2O and recrystallized into [C(NH2)3]2[B4O5(OH)4]•2H2O, which is further dissolved and recrystallized in MeOH to obtain Gd-B (path 2).
