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We report a 2-fold interpenetrated primitive cubic (pcu) network X-pcu-5-Zn, [Zn 2 (DMTDC) 2 -(dpe)] (H 2 DMTDC = 3,thiophene-2,5-dicarboxylic acid, dpe = 1,2-di(4-pyridyl)ethylene), that exhibits reversible switching between an as-synthesized "open" phase, X-pcu-5-Zn-α, and two nonporous or "closed" polymorphs, X-pcu-5-Zn-β and X-pcu-5-Zn-γ. There are two unusual features of X-pcu-5-Zn. The first relates to its sorption properties, which reveal that the α form exhibits high CO 2 uptake (ca. 255 cm 3 /g at 195 K) via reversible closed-to-open switching (type F-IV isotherm) of the type desirable for gas and vapor storage; there are only three other reports of porous materials that combine these two features. Second, we could only isolate the β form by activation of the CO 2 loaded α form and it persists through multiple CO 2 adsorption/desorption cycles. We are unaware of a new polymorph having been isolated in such a manner. That the observed phase changes of X-pcu-5-Zn-α occur in single-crystal-to-single-crystal fashion enabled structural characterization of the three forms; γ is a coordination isomer of α and β, both of which are based upon "paddlewheel" clusters.

Closed-to-open structural transformations in flexible coordination networks are of potential utility in gas storage and separation. Herein, we report the first example of a flexible SiF6 2–-pillared square grid material, [Cu­(SiF6)­(L)2] n (L = 1,4-bis­(1-imidazolyl)­benzene), SIFSIX-23-Cu. SIFSIX-23-Cu exhibits reversible switching between nonporous (β1) and several porous (α, γ1, γ2, and γ3) phases triggered by exposure to N2, CO2, or H2O. In addition, heating β1 to 433 K resulted in irreversible transformation to a closed polymorph, β2. Single-crystal X-ray diffraction studies revealed that the phase transformations are enabled by rotation and geometrical contortion of L. Density functional theory calculations indicated that L exhibits a low barrier to rotation (as low as 8 kJmol–1) and a rather flat energy surface. In situ neutron powder diffraction studies provided further insight into these sorbate-induced phase changes. SIFSIX-23-Cu combines stability in water for over a year, high CO2 uptake (ca. 216 cm3/g at 195 K), and good thermal stability.

This study is based on the heterogeneous nucleation of active pharmaceutical ingredients (APIs) 2 in the presence of various excipients widely used in the pharmaceutical industry. Carbamazepine (CBMZ) was successfully crystallized in the presence of the following heterosurfaces: α/β-4 Lactose, β-D-Mannitol, microcrystalline cellulose and carboxymethyl cellulose. The successful 5 crystallization of CBMZ FIII in the presence of all the excipients was confirmed by powder X-6 ray diffraction and scanning electron microscopy, while CBMZ crystals apposition was 7 confirmed using in-situ SEM-Raman. A pronounced improvement in the dissolution of CBMZ 8 FIII was observed when crystallized in the presence of excipients when compared with CBMZ 9 FIII recrystallized using same conditions in the absence of the excipients. The isolated solids 10 could be simply tabletted by direction compression upon mixing with the desired amount of 11 disintegrant and lubricant. Hence employing this process could potentially streamline the 12 downstream process in pharmaceutical industries and also increase the throughput with reduced 13 cost. 14

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