Postsynthetic covalent modification of metal-organic frameworks (MOFs) with long alkyl substituents is shown to protect these materials against moisture. These MOFs, which normally display hydrophilic properties, are readily converted into hydrophobic or superhydrophobic materials. Overcoming the inherent sensitivity of MOFs to water represents a major step forward in their widespread use in technology applications.Metal-organic frameworks (MOFs) are porous, crystalline materials that are attractive for applications in gas adsorption, 1 separations, 2 and catalysis 3,4 because of their chemical tunability, high porosities, and good thermal stability. 5 Unfortunately, some of the most promising materials are limited because of an instability with respect to moisture. [6][7][8] Stabilizing these MOFs against ambient humidity would make these porous materials more suitable for specialized and industrial applications. The postsynthetic modification (PSM) approach, which has become an important tool in developing functionally diverse systems and introducing new physical and chemical properties into MOFs, 9 offers an opportunity to address this challenge.Amine-containing MOFs can readily undergo PSM to form amide-functionalized MOFs. 10,11 It was hypothesized that the introduction of hydrophobic alkyl chains via PSM could improve the moisture resistance and change the physical properties (i.e. hydrophobicity) of these MOFs. The effect of PSM on two different MOF systems was examined (Figure 1). Isoreticular metal-organic frameworks (IRMOFs) are cubic frameworks comprised of Zn 4 O clusters and dicarboxylate ligands. In this study, IRMOFs constructed of 1,4-benzenedicarboxylate (BDC, IRMOF-1), 2-amino-1,4-benzenedicarboxylate (NH 2 -BDC, IRMOF-3), and PSM derivatives of the latter were investigated. The second MOF systems examined belong to the Material Institut Lavoisier (MIL) class of materials, 12 specifically, MIL-53(Al)-NH 2 a flexible MOF comprised of infinite Al 3+ clusters and NH 2 -BDC. The IRMOFs are generally considered sensitive to moisture, while the MILs are stable to water and other polar solvents (indeed MIL-53(Al)-NH 2 is synthesized in water). In order to assess changes in the moisture stability and hydrophobicity/philicity of the materials upon PSM, each material was exposed to ambient air or immersed in water and then characterized using scohen@ucsd.edu. Supporting Information Available: Experimental details, Table S1, Figures S1-S17. NIH Public AccessAuthor Manuscript J Am Chem Soc. Author manuscript; available in PMC 2011 April 7. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript contact angle measurements, powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM).Contact angle measurements are commonly used to examine the hydrophobic/philic properties of materials. Hydrophilic materials display contact angles less than 90°. Contact angles between 90° and 150° are found for hydrophobic materials, and materials with contact angles >150° are considered ...

When campuses across the world needed to transition to the online format due to the COVID-19 pandemic, there were many challenges educators faced, and addressing academic integrity issues were some of the most important. Certain strategies, such as online proctoring or additional software, were not available to most institutions because the expenses and training were too much to overcome. A more pedagogical and cost-effective strategy involved modifying the assessment format in a way that minimized or discouraged cheating. This paper presents strategies that effectively minimize cheating while addressing learning outcomes.

Two different metal-organic frameworks (MOFs) have been modified with nitric oxide (NO) through covalent postsynthetic modification (PSM) to form diazeniumdiolate-functionalized and releasing MOFs.

No abstract

The prostate apoptosis response protein 4 (Par-4) is a tumor-suppressor that has been shown to induce cancer-cell selective apoptosis in a variety of cancers. The regulation of Par-4 expression and activity is a relatively understudied area, and identifying novel regulators of Par-4 may serve as novel therapeutic targets. To identify novel regulators of Par-4, a co-immunoprecipitation was performed in colon cancer cells, and co-precipitated proteins were identified by mass-spectometry. TRIM21 was identified as a novel interacting partner of Par-4, and further shown to interact with Par-4 endogenously and through its PRY-SPRY domain. Additional studies show that TRIM21 downregulates Par-4 levels in response to cisplatin, and that TRIM21 can increase the resistance of colon cancer cells to cisplatin. Furthermore, forced Par-4 expression can sensitize pancreatic cancer cells to cisplatin. Finally, we demonstrate that TRIM21 expression predicts survival in pancreatic cancer patients. Our work highlights a novel mechanism of Par-4 regulation, and identifies a novel prognostic marker and potential therapeutic target for pancreatic cancer.