RESUMEN
Two Cd(II)-organic frameworks based on 5-iodoisophthalate (IIP(2-)), {[Cd(IIP)(bte)(H2O)]·H2O}n (1) and [Cd(IIP)(bpp)(H2O)]n (2), were obtained either at an ambient temperature or under solvothermal conditions at 120 °C in the presence of 1,4-bis(1,2,4-triazol-1-yl)ethane (bte) and 1,3-bis(4-pyridyl)propane (bpp) as auxiliary ligands, respectively. 1 is a novel discrete single-walled Cd(II)-organic tube (SWCOT) which further extends into a 3D supramolecular interdigitated microporous columnar architecture supported by C-I···I halogen bonds and hydrogen bonds, while 2 exhibits an interesting two-fold interpenetrated 3D diamond network architecture. When the auxiliary ligands bte or bpp were replaced by a longer spacer ligand with more flexibility, 1,4-bis(triazol-1-ylmethyl)benzene (bbtz), the unique discrete single-walled Cd(II)-organic nanotube (SWCONT), {[Cd(IIP)(bbtz)(H2O)]·H2O}n (3), which further extends into a 3D supramolecular microporous framework supported by face-to-face π···π stacking interactions and hydrogen bonds, was generated at room temperature. Under solvothermal conditions at 120 °C, an interesting two-fold 2D "embracing" (4,4) topological network, [Cd(IIP)(bbtz)(H2O)] (4), which further extends into a two-fold 3D "embracing" supramolecular framework through O-H···O hydrogen bonds, is obtained. 4 loses crystallinity in air, leading to the formation of [Cd(IIP)(bbtz)]·0.5H2O (4A) evidenced by elemental analysis, thermogravimetric analysis (TGA) and powder X-ray diffraction (PXRD). Remarkably, in situ rapid and reversible dehydration-rehydration in static air occurs in 1-3, indicating their potential applications as water absorbent and sensing materials. Dehydrated 1 and 3 show selective gas adsorption of CO2 over N2 and dehydrated 3 can adsorb methanol and ethanol vapors strongly. These compounds exhibit blue fluorescence in the solid state.
RESUMEN
An electrochemical method has been successfully demonstrated for sensitive determination of azithromycin (Azi) with room temperature ionic liquid (IL) of 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF(6)) - graphene (Gr) composite modified glassy carbon electrode (GCE). The cyclic voltammetric results indicate that Gr/IL/GCE can remarkably enhance electrocatalytic activity towards the oxidation of Azi in neutral solutions. Azi produce an anodic peak at about 0.82 V at this electrode. The electrocatalytic behavior was further exploited as a sensitive detection scheme for the Azi determination by differential-pulse voltammetry (DPV). Under optimized conditions, the concentration range and detection limit were 0.49-28.57 µg ml(-1) and 0.19 µg ml(-1) (S/N=3) respectively for Azi. The method was successfully applied assay of the drug in the pharmaceutical dosage forms.