Jason A. Perman

Supermolecular building blocks (SBBs) and crystal design: 12-connected open frameworks based on a molecular cubohemioctahedron.

The cubohemioctahedral supermolecular building blocks, SBBs, of formula [M6(bdc)12]12- (M = Ni, Co) (as illustrated) have the requisite symmetry to be cross-linked by rigid tetracarboxylato ligands in such a manner that 12-connected fcu nets with nanoscale features are generated. 3,5-H4ATC, L1, facilitates a structure with Ni that exhibits cavities with >2 nm maximum dimensions, whereas H4BIPA-TC, L2, forms a net with Co or Ni that exhibits cavities with >3 nm maximum dimensions.

A General and Efficient Cobalt(II)-Based Catalytic System for Highly Stereoselective Cyclopropanation of Alkenes with α-Cyanodiazoacetates

[Co(P1)], the cobalt(II) complex of the D(2)-symmetric chiral porphyrin 3,5-Di(t)Bu-ChenPhyrin, is an effective catalyst for catalyzing asymmetric olefin cyclopropanation with the acceptor/acceptor-type diazo reagent α-cyanodiazoacetates. The [Co(P1)]-catalyzed reaction is versatile and suitable for both aromatic and aliphatic olefins with varied electronic properties, including electron-rich and -poor olefins. The Co(II)-based catalytic system can be operated in a one-time protocol under mild conditions, affording the desired cyclopropane products in high yields with both high diastereo- and enantioselectivity. The resulting enantiomerically enriched 1,1-cyclopropanenitrile esters provide convenient access to a number of densely functionalized chiral cyclopropane derivatives, including α-cyclopropyl-β-amino acids.

Metal-Organic Frameworks for CO2 Chemical Transformations

Carbon dioxide (CO2 ), as the primary greenhouse gas in the atmosphere, triggers a series of environmental and energy related problems in the world. Therefore, there is an urgent need to develop multiple methods to capture and convert CO2 into useful chemical products, which can significantly improve the environment and promote sustainable development. Over the past several decades, metal-organic frameworks (MOFs) have shown outstanding heterogeneous catalytic activity due in part to their high internal surface area and chemical functionalities. These properties and the ability to synthesize MOF platforms allow experiments to test structure-function relationships for transforming CO2 into useful chemicals. Herein, recent developments are highlighted for MOFs participating as catalysts for the chemical fixation and photochemical reduction of CO2 . Finally, opportunities and challenges facing MOF catalysts are discussed in this ongoing research area.

Asymmetric Co(II)-Catalyzed Cyclopropanation with Succinimidyl Diazoacetate: General Synthesis of Chiral Cyclopropyl Carboxamides

[Co(P1)] is an effective catalyst for asymmetric cyclopropanation with succinimidyl diazoacetate. The Co(II)-catalyzed reaction is suitable for various olefins, providing the desired cyclopropane succinimidyl esters in high yields and excellent diastereo- and enantioselectivity. The resulting enantioenriched cyclopropane succinimidyl esters can serve as convenient synthons for the general synthesis of optically active cyclopropyl carboxamides.

A bifunctional metal–organic framework featuring the combination of open metal sites and Lewis basic sites for selective gas adsorption and heterogeneous cascade catalysis

A bifunctional MOF (JUC-199) featuring dual functionality, open metal sites (Zn2+) and Lewis basic sites (–NH2), has been successfully synthesized using a custom-designed ligand. JUC-199 demonstrated good selective gas sorption behaviours with IAST selectivity values of 9, 30, 37 and 64 at 298 K and 101 kPa for CO2/CH4, CO2/N2, C2H6/CH4 and C2H4/CH4 respectively; surpassing those of most MOFs reported thus far. Moreover, JUC-199 can serve as a heterogeneous cascade catalyst to efficiently catalyse the tandem one-pot deacatalization-Knoevenagel condensation reaction.

Norselic Acids A−E, Highly Oxidized Anti-infective Steroids that Deter Mesograzer Predation, from the Antarctic Sponge Crella sp.

Five new steroids, norselic acids A-E (1-5), were isolated from the sponge Crella sp. collected in Antarctica. The planar structures of the norselic acids were established by extensive NMR spectroscopy and mass spectrometry studies, and the configuration of norselic acid A (1) was elucidated by X-ray crystallography. Norselic acid A displays antibiotic activity against methicillin-resistant Staphylococcus aureus (MRSA), methicillin-sensitive S. aureus (MSSA), vancomycin-resistant Enterococcus faecium (VRE), and Candida albicans and reduces consumption of food pellets by sympatric mesograzers. Compounds 1-5 are also active against the Leishmania parasite at low micromolar levels.

Efficient Mercury Capture Using Functionalized Porous Organic Polymer

The primary challenge in materials design and synthesis is achieving the balance between performance and economy for real-world application. This issue is addressed by creating a thiol functionalized porous organic polymer (POP) using simple free radical polymerization techniques to prepare a cost-effective material with a high density of chelating sites designed for mercury capture and therefore environmental remediation. The resulting POP is able to remove aqueous and airborne mercury with uptake capacities of 1216 and 630 mg g-1 , respectively. The material demonstrates rapid kinetics, capable of dropping the mercury concentration from 5 ppm to 1 ppb, lower than the US Environmental Protection Agencys drinking water limit (2 ppb), within 10 min. Furthermore, the material has the added benefits of recyclability, stability in a broad pH range, and selectivity for toxic metals. These results are attributed to the materials physical properties, which include hierarchical porosity, a high density of chelating sites, and the materials robustness, which improve the thiol availability to bind with mercury as determined by X-ray photoelectron spectroscopy and X-ray absorption fine structure studies. The work provides promising results for POPs as an economical material for multiple environmental remediation applications.

A metal–organic framework and conducting polymer based electrochemical sensor for high performance cadmium ion detection

In this work, a conductive electrochemical sensor, UiO-66-NH2@PANI, was successfully prepared by polymerizing the conductive polyaniline (PANI) polymer around the metal–organic framework UiO-66-NH2. Fourier transform infrared spectra, X-ray diffraction patterns, and X-ray photoelectron spectral data support the formation of UiO-66-NH2@PANI. Additionally, scanning and transmission electron microscopy investigations confirm that PANI uniformly coated the surface of UiO-66-NH2. The resultant material was applied to construct a novel electrochemical sensor for the reliable detection of cadmium ions due to the chelation mechanism between metal cations and amine groups. Under optimized conditions, a linear detection of Cd2+ concentration range of 0.5–600 μg L−1 was repeatable with a 0.3 μg L−1 lowest level detection limit. Little to no interference effects from other co-existing ions allow the sensor to work in varying environments for practical application. This method of coating metal–organic frameworks may show utility for constructing highly sensitive electrochemical sensors for the detection of heavy metal ions and more.

Cocrystal controlled solid-state synthesis of a rigid tetracarboxylate ligand that pillars both square grid and Kagomé lattice layers

[Cu2(carboxylate)4] paddlewheel molecular building blocks, MBBs, are capable of generating square grid or Kagome lattice supramolecular isomers when dicarboxylates such as 1,3-benzenedicarboxylate (1,3-bdc) and 1,4-benzenedicarboxylate (1,4-bdc) are exploited to link the paddlewheel MBBs. In this contribution we demonstrate that it is possible to use a solvent-free reaction (cocrystal controlled solid-state synthesis) to prepare a tetracarboxylic acid, H44BIPA-TC, formed by rigidly linking two 1,3-bdc moieties at the 5-position. BIPA-TC can pillar both square grid and Kagome lattice supramolecular isomers, thereby generating nets that exhibit lvt or nbo topologies, respectively.

A Stable Metal–Organic Framework Featuring a Local Buffer Environment for Carbon Dioxide Fixation

A majority of metal-organic frameworks (MOFs) fail to preserve their physical and chemical properties after exposure to acidic, neutral, or alkaline aqueous solutions, therefore limiting their practical applications in many areas. The strategy demonstrated herein is the design and synthesis of an organic ligand that behaves as a buffer to drastically boost the aqueous stability of a porous MOF (JUC-1000), which maintains its structural integrity at low and high pH values. The local buffer environment resulting from the weak acid-base pairs of the custom-designed organic ligand also greatly facilitates the performance of JUC-1000 in the chemical fixation of carbon dioxide under ambient conditions, outperforming a series of benchmark catalysts.