title: Apical ligand substitution, shape recognition, vapor-adsorption phenomenon, and microcalorimetry for a pillared bilayer porous framework that shrinks or expands in crystal-to-crystal manners upon change in the cobalt(II) coordination environment.
abstract: A 2D pillared bilayer coordination polymer, [Co(5-NH(2)-bdc)(bpy)(0.5)(H(2)O)] x 2 H(2)O (1; 5-NH(2)-bdc = 5-aminoisophthalate; bpy = 4,4'-bipyridine) has been hydrothermally synthesized and shows a novel microporous host framework with 1D channels and high thermal stability (approximately 400 degrees C). The framework of 1 exhibits reversible single-crystal-to-single-crystal transformations upon removing and rebinding the coordinated waters as well as replacing them with MeOH and EtOH from the solvent. X-ray crystallography reveals that the coordination geometry of Co(II) changes from octahedron to square pyramid, as well as the shrinkage/expansion of pore deformation in respect to the subsequent shear motion of bpy pillars and vice versa. The dehydrated form 2 exhibits a shape recognition ability, which can accommodate linear molecules, such as MeCN and 2-propynyl alcohol, and interesting storage capabilities for oversized MeOH, EtOH, and benzene molecules, concomitant with spongelike dynamic transformation. The microcalorimetric study indicates that the crystalline state-liquid guest exchange and guest inclusion processes (1 superset MeOH or EtOH, 2 superset MeOH, EtOH or MeCN) are feasibly endothermic reactions with the values of molar enthalpy, DeltaH(theta)(m), of +21.38(96), +12.68(85), +25.92(86), +17.03(57), and +14.93(75) kJ mol(-1), respectively.
authors: Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of Chemistry & Chemical Engineering of Guangxi Normal University, Guilin 541004, PR China. zmh@mailbox.gxnu.edu.cn
authors: Ming-Hua
authors: MH
authors: Zeng
authors: Sheng
authors: S
authors: Hu
authors: Qing
authors: Q
authors: Chen
authors: Gang
authors: G
authors: Xie
authors: Qi
authors: Q
authors: Shuai
authors: Sheng-Li
authors: SL
authors: Gao
authors: Li-Yuan
authors: LY
authors: Tang