A Multistimuli Responsive Crystalline Cd(II)-Viologen Coordination Polymer with Single-Crystal-Single-Crystal Transformation.

It is necessary to develop stable and fast multistimuli responsive materials due to the growing demand in our daily life. In this work, a new viologen-based Cd-complex (1) exhibits multiple thermochromic and photochromic behaviors through 10 states with 7 colors. For example, it responds to both Cu Kα/Mo Kα X-ray sources and UV dual light quickly with a color change from colorless to dark blue (1X) (Cu Kα/Mo Kα X-ray sources) and cyan (1-UV) (UV light), respectively. Interestingly, it exhibits a three-step coloration phenomenon when heated, which is unprecedented in viologen compounds. Crystal 1 undergoes a color change to pink, blue, and brown under 130, 180, and 240 °C, respectively. In addition, upon fumigation, both 1P and 1Q undergo a decoloration process to colorless (1K) and yellow (1T), respectively. Four more states (1P, 1K, 1T, and 1O) obtained via dehydration-hydration treatment are all photochromic. More importantly, via single-crystal-single-crystal transformation (SC-SC), the photochromic and thermochromic behaviors of 1 were investigated from the molecular level, which is also rather rare for thermochromic species. The detailed electron donor and the pathways for electron transfer were clearly given according to the results of crystal structure. The colorful states upon external stimuli may be attributed to the multiple pathways for electron transfer.

Cocrystallization with syringic acid presents a new opportunity for effectively reducing the hepatotoxicity of isoniazid.

Objective: With the aim of surmounting the severe hepatotoxicity induced by antituberculosis drug isoniazid (INH), a novel cocrystal of INH with hepatoprotective nutraceutical syringic acid (SYA), namely INH-SYA, was designed and prepared through cocrystallization strategy, which is an intriguing attempt to reduce the toxic side effects of INH.Significance: The study not only provides new thinking for inhibiting toxic side effects of drugs through cocrystallization strategy, but also opens a new pathway for the application of nutraceuticals in the pharmacy.Methods: INH and SYA were successfully crystallized into the same crystal lattice through combining volatilization with solvent assisted methods. The resulting cocrystal was structurally characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and differential scanning calorimetry (DSC).Results: The SCXRD analysis for the present cocrystal revealed that it has a 1:1 ratio of INH to SYA with two molecules INH homodimers and two SYA molecules, in which they are arranged alternately linked by hydrogen bonds to form a six molecules ring structure (R66(40)) in crystal. The systematic evaluation of the in vitro/in vivo suggested that, owing to the formation of cocrystal, the dissolution efficiency of SYA was increased 5.85-fold compared with that of coarse SYA, and the oral bioavailability of the cocrystal in rats was enhanced by 3.66 times. As a result, the present INH-SYA cocrystal almost removed INH induced serious hepatotoxicity, which was further demonstrated by the hepatotoxicity studies in rats.Conclusion: INH-SYA cocrystal could effectively reduce the hepatotoxicity of INH.

[Mu3-cis-N-(2-aminoethyl)-N'-(2-carboxylatophenyl)oxamidato(3-)]bis(2,2'-diamino-4,4'-bi-1,3-thiazole)tetracopper(II) bis(2,4,6-trinitrophenolate).

The title complex, [Cu(4)(C(11)H(10)N(3)O(4))(2)(C(6)H(6)N(4)S(2))(2)](C(6)H(2)N(3)O(7))(2), consists of a circular tetracopper(II) cation with an embedded inversion centre and two uncoordinated picrate (2,4,6-trinitrophenolate) anions. The Cu(II) cations at the inner sites of N-(2-aminoethyl)-N'-(2-carboxylatophenyl)oxamidate(3-) (oxbe) have square-planar environments and those at the outer sites are in square-pyramidal geometries. The separations of pairs of Cu(II) cations bridged by cis-oxamide and carboxylate groups are 5.2217 (5) and 5.2871 (5) A, respectively. The tetracopper(II) cations and picrate anions are connected by N-H...O hydrogen bonds into a two-dimensional network parallel to the (010) plane, and these two-dimensional networks are assembled by two types of pi-pi stacking interactions into a three-dimensional supramolecular structure.

Poly[bis-(µ(3)-5-nitro-isophthalato)bis-(1,10-phenanthroline)dimanganese(II)].

The title complex, [Mn(2)(C(8)H(3)NO(6))(2)(C(12)H(8)N(2))(2)](n), was synthesized under hydro-thermal conditions. The structure contains two independent Mn(II) atoms, each coordinated in a distorted octa-hedral MnN(2)O(4) geometry. [Mn(2)(phen)(2)] units (phen = 1,10-phenantroline) are bridged by 5-nitro-isophthalate (nip) ligands into ladder-like chains parallel to [100]. Adjacent polymeric chains are linked by C-H⋯O and π-π inter-actions [centroid-to-centroid distance = 3.6369 (12) Å] into a two-dimensional framework parallel to (010).