Copper Metal-Organic Framework Surface Catalysis: Catalyst Poisoning, IR Spectroscopic, and Kinetic Evidence Addressing the Nature and Number of the Catalytically Active Sites En Route to Improved Applications.

The metal-organic framework (MOF) H[(CuCl)-(BTTri), HBTTri = 1,3,5-tris(H-1,2,3-triazol-5-yl)benzene] (CuBTTri) is a precatalyst for biomedically relevant nitric oxide (NO) release from nitrosoglutathione (GSNO). The questions of the number and nature of the catalytically most active, kinetically dominant sites are addressed. Also addressed is whether or not the well-defined structural geometry of MOFs (as solid-state analogues of molecular compounds) can be used to generate specific, testable hypotheses about, for example, if intrapore vs exterior surface metal sites are more catalytically active.

Homochiral Metal-Organic Frameworks for Enantioselective Separations in Liquid Chromatography.

Selective separation of enantiomers is a substantial challenge for the pharmaceutical industry. Chromatography on chiral stationary phases is the standard method, but at a very high cost for industrial-scale purification due to the high cost of the chiral stationary phases. Typically, these materials are poorly robust, expensive to manufacture, and often too specific for a single desired substrate, lacking desirable versatility across different chiral analytes.

Copper ion vs copper metal-organic framework catalyzed NO release from bioavailable S-Nitrosoglutathione en route to biomedical applications: Direct H NMR monitoring in water allowing identification of the distinct, true reaction stoichiometries and thiol dependencies.

Copper containing compounds catalyze decomposition of S-Nitrosoglutathione (GSNO) in the presence of glutathione (GSH) yielding glutathione disulfide (GSSG) and nitric oxide (NO). Extended NO generation from an endogenous source is medically desirable to achieve vasodilation, reduction in biofilms on medical devices, and antibacterial activity. Homogeneous and heterogeneous copper species catalyze release of NO from endogenous GSNO.

Amino-Incorporated Tricarboxylate Metal-Organic Framework for the Sensitive Fluorescence Detection of Heavy Metal Ions with Insights into the Origin of Photoluminescence Response.

Metal-organic frameworks (MOFs) are powerful chemosensors when designed to undergo a detectable change in optical properties upon interacting with target analytes. This work contributes to the overall understanding of metal-ion interactions with MOFs to elicit changes in fluorescence emission, a necessary step en route to developing more sensitive and selective systems for metal-ion sensing. Toward this goal, the photophysical properties of an amino-containing MOF, Cu(NHBTC), were investigated.

Surface-Anchored Metal-Organic Framework-Cotton Material for Tunable Antibacterial Copper Delivery.

In the present study, a new copper metal-organic framework (MOF)-cotton material was strategically fabricated to exploit its antibacterial properties for postsynthetic modification (PSM) to introduce a free amine to tune the physicochemical properties of the material. A modified methodology for carboxymethylation of natural cotton was utilized to enhance the number of nucleation sites for the MOF growth. Subsequently, MOF Cu(NHBTC) was synthesized into a homogenous surface-supported film via a layer-by-layer dip-coating process.

Enantiospecific Synthesis of β-Substituted Tryptamines.

Functionalized tryptamines are targets of interest for development as small molecule therapeutics. The ring opening of aziridines with indoles is a powerful method for tryptamine synthesis where isomer formation can be controlled. 3,5-Dinitrobenzoyl (DNB)-protected aziridines undergo regioselective, enantiospecific ring opening to produce β-substituted tryptamines for a series of indoles.

Functionalization of Metal-Organic Frameworks To Achieve Controllable Wettability.

The overall versatility of a material can be immensely expanded by the ability to controllably tune its hydrophobicity. Herein we took advantage of steric bias to demonstrate that tricarboxylate metal-organic frameworks (MOFs) can undergo covalent postsynthetic modification to confer various degrees of hydrophobicity. MOF copper 2-aminobenzene-1,3,5-tricarboxylate was modified with varying-length aliphatic carbon chains.

Scalable synthesis of N-acylaziridines from N-tosylaziridines.

N-Acylaziridines are important starting materials for the synthesis of chiral amine derivatives. The traditional methods for producing these activated aziridines have significant drawbacks. The gram scale synthesis of N-acylaziridines by deprotection of N-tosylaziridines and reprotection with N-hydroxysuccinimide derivatives is described.

Enantioselective synthesis and stereoselective ring opening of N-acylaziridines.

Kinetic resolution of N-acylaziridines by nucleophilic ring opening was achieved with (R)-BINOL as the chiral modifier under boron-catalyzed conditions (see scheme; Ar=3,5-dinitrophenyl). The consumed enantiomer of aziridine can be further converted to an enantioenriched 1,2-chloroamide with recovery of (R)-BINOL.