Dynamic structural reconstruction of (guanidinium+)2(benzene-1,4-disulfonate2-) host crystal by guest adsorption

Guanidinium (G(+)) and benzene-1,4-disulfonate (BDS2-) form a rigid electrostatic cation-anion crystal lattice, which undergoes an interesting dynamic structural reconstruction through guest adsorption-desorption processes with H2O, pyrrole (Pyrr), pyrazine (Pyz), thiophene (TP), pyridine (Py), 1,4-dioxane (Diox), or aniline (Ani). The host lattice of bis(guanidinium)benzene-1,4-disulfonate, (G(+))(2)(BDS2-), which does not contain void spaces initially, changed to host-guest crystals of (G(+))(2)(BDS2-)center dot(guest)(x) upon guest adsorption (x = 1, 2, and 3). The cation-anion electrostatic N-H+MIDLINE HORIZONTAL ELLIPSIS-O3S- hydrogen bonds between the G(+) cation and BDS2- dianion formed tightly bound two-dimensional (2D) structures. These layers are connected by perpendicular BDS2- dianions, forming the guest adsorption crystalline pores. The adsorption-desorption isotherm for Diox at 298 K indicated the formation of (G(+))(2)(BDS2-)center dot(Diox)(3), which was consistent with the single-crystal X-ray structural analysis. Single crystals of (G(+))(2)(BDS2-)center dot(Py-H2O)(2) consist of two hydrogen-bonded [(G(+))(2)(BDS2-)](2) bilayers connected by the BDS2- dianions, forming crystalline pores that accommodate 2 Py guest molecules. The H2O molecules in (G(+))(2)(BDS2-)center dot(Py-H2O)(2) are lodged in the intralayer, leading to the [(G(+))(2)(BDS2-)MIDLINE HORIZONTAL ELLIPSIS(H2O)(2)MIDLINE HORIZONTAL ELLIPSIS(G(+))(2)(BDS2-)] hydrogen-bonded bilayer. The electrostatic cation-anion host lattice of (G(+))(2)(BDS2-) responded to the guest adsorption-desorption cycle by a dynamic structural reconstruction. A guest adsorption of polar Ani into (G(+))(2)(BDS2-) host changed the crystal symmetry from centric P1 to acentric P2(1) of (G(+))(2)(BDS2-)center dot(Ani)(3).

Automated summary

Guanidinium and benzene-1,4-disulfonate form a rigid electrostatic cation-anion crystal lattice, which undergoes dynamic structural reconstruction through guest adsorption-desorption processes, resulting in the formation of host-guest crystals and crystalline pores.