RESUMEN
Rare-earth (RE) metal-organic frameworks (MOFs) offer unique optical, electronic, and magnetic properties. RE metals tend to make binuclear metal nodes resulting in dense nonporous coordination networks. Three dimensional porous RE-MOFs have been reported by preparing bigger metal nodes based on metal clusters often found as hexaclusters or nonaclusters. The formation of metal clusters (>2 metal ions) generally requires the use of fluorinated organic molecules reported as modulators. However, it was recently discovered that these molecules are not modulators, rather they act as reactants and leave fluorine in the metal clusters. The formation and types of fluorinated RE metal clusters have been discussed. These fluorinated clusters offer higher connectivity which results in porous MOFs. The presence of fluorine in these metal clusters offers unique properties, such as higher thermal stability and improved fluorescence. This frontier summarizes recent progress and gives future perspective on the fluorinated metal clusters in the RE-MOFs.
RESUMEN
A new fluoro-bridged rare-earth (RE) metal-organic framework consisting of 15-connected nonanuclear and 9-connected trinuclear clusters {[RE9-(µ3-F)14(H2O)6][RE3(µ3-F)(H2O)3](HCO2)3-(BTB)6}·(solvent)x 2 (RE = Ho3+ and Gd3+) was synthesized through the transformation of a dimeric complex formulated as bis(2,2'-bipyridine)tetrakis(µ-2-fluorobenzoato-O,O')-bis(2-fluorobenzoato)diRE(III) 1 with the bridging linker 1,3,5-tris(4-carboxyphenyl)benzene (H3BTB). The rare-earth metal ions Ho3+ and Gd3+ were also found to remove fluorine from other organo-fluorine compounds such as perfluorohexanoic acid (PFHxA) and perfluorooctanoic acid (PFOA), resulting in the new fluoro-bridged RE-MOFs.
RESUMEN
5-Fluorouracil (5-Fu) commonly use in the treatment of different kinds of cancer, but limited cellular uptake and death is still a problem. Herein, we report a simple process for the synthesis of pressure-sensitive nanogels that indicate to be appropriate in the delivery of 5-Fu. The hydrogels (Al-CD) prepare by crosslinking of alginate (Al) with modified beta Cyclodextrin (ß-CD) as Crosslinker. Next, nanoparticles obtaine by an emulsification method. 5-Fu as model drug loades into the Al-CD nanogels easily by mixing it in aqueous solution with the nanoparticles. The results revealed that the Al-CD nanogels are cytocompatible. They have also a noticeable drug encapsulation (82.1 ±5.7%) while they can release (in vitro controlled) 5-Fu in conditions that imitate the intravascular pressure conditions. These nanogels can rapidly be taken up by HT-29 cells (a colon cell line). In addition, a higher 5-Fu intracellular accumulation and a significant cell death extension by apoptosis mechanism is notice when compare with free 5-Fu. Accordingly, the developed nanogels can be employe as an excellent candidate to overcome the inefficiency of 5-Fu in anticancer treatments and possibly can employe for further evaluation as a chemotherapical agent in applications beyond cancer. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 349-359, 2018.
