In situ visualization of loading-dependent water effects in a stable metal–organic framework
December 02, 2019
Nature Chemistry (2019)
Even for MOFs that are highly stable in humid environments, a static representation of the framework structure may not be sufficient to understand the observed stability. This work has shown that the DMOF-TM framework has a dynamic and reversible structural response to water guest molecules, observed in changes in the unit cell parameters, microstrain, vibrational spectra and atomic structure. These changes manifest themselves at low guest loading and continue to change in response to guest loading.
Nanosheets Synthesis under Mixed Surfactants
October 11, 2019
Chem. Mater. 2019, 31, 21, 9040-9048
Two-dimensional monocrystalline oxide nanomaterials have a great impact on material innovation and property advancement. However, creating them with fine control remains a grand challenge. Inspired by the biomineralization processes, researchers from the University of Wisconsin-Madison were able to synthesize the monocrystalline 2D nanosheets under the mix-charges amphiphilic monolayer. The growth process was monitored by in-situ grazing incidence X-ray diffractions at NSF’s ChemMatCARS.
*Reprinted with permission from Chem. Mater. 2019, 31, 21, 9040-9048. Copyright 2019 American Chemical Society.
Characterization of a Reactive Rh2 Nitrenoid by Crystalline Matrix Isolation
September 24, 2019
J. Am. Chem. Soc. 2019, 141, 41, 16232 –16236
The scientists from Texas A&M University and The University of Chicago report the first X-ray crystal structure of a reactive Rh2 nitrenoidis, enabled by N2 elimination from an organic azide ligand within a single-crystal matrix. The resulting high-resolution structure displays metrical parameters consistent with a triplet nitrene complex of Rh2. The demonstration of facile access to reactive metal nitrenoids within a crystalline matrix provides a platform for structural characterization of the transient species at the heart of C–H functionalization.
The Role of Ligands on Bio-Nano Interactions
Nanoparticles targeting biological membranes leads to multiple biomedical effects. The coating ligands are known to affect the nanoparticle-membrane interaction. However, the molecular mechanisms of this modulation remain unresolved. Researchers from Chinese Academy of Sciences, Columbia University, and University of Chicago combined X-ray liquid surface scattering and MD simulations to investigate the role of coating ligands on the nanoparticle-membrane binding at the water surface.
Ligand‐Based Control of Single‐Site vs. Multi‐Site Reactivity by a Trichromium Cluster
March 3, 2019
Angew. Chem. 2019, 131, 5743 –5747
The reactivity of this complex demonstrates the ability of the cluster-templating ligand to produce a well-defined polynuclear transition metal cluster that can access distinct single-site and cooperative reactivity controlled by either substrate steric demands or reaction media.
Element Selectivity of Solvent Extraction
Solvent extraction technique has been widely used in mining and refinement of rare earths. Although all rare earths are chemically similar, the extraction efficiency increases as a function of atomic number. Combining MC simulation and X-ray fluorescence measurements at NSF’s ChemMatCARS, researchers from Northwestern University and The University of Chicago revealed the electrostatic origin of this selectivity.
Phospholipid-Phospholipase Interaction on Water Surface
Overexpressed intrinsic enzymes such as secretory phospholipase A2 (sPLA2) have been used to trigger the local drug release from lipid vesicles. sPLA2 can catalyze the hydrolysis of one tail of a phospholipid, which yields equimolar fatty acid and lysophospholipid. However, little is known about this process on the molecular length scale. A recent study by researchers from University of Illinois at Chicago uncovered molecular interactions of phospholipids with enzymes.
Role of hydrophobicity in peptide-membrane interactions
BBA – Biomembranes, 2018, 1860, pp 1414-1423
Antimicrobial peptides (AMPs) target bacterial cells mainly by electrostatic interactions. Studies indicate that the hydrophobicity of AMPs plays an important role on the selectivity. By using the X-ray reflectivity technique at NSF’s ChemMatCARS and other characterization tools, researchers from Illinois Institute of Technology and New York University have investigated the molecular basis for peptoid interactions with bacterial and eukaryotic lipid membranes on the sub-nanometer scale.
Thermally Persistent High-Spin Ground States in Octahedral Iron Clusters
November 7, 2018
J. Am. Chem. Soc., 2018, 140 (48), pp 16792-16806
In this paper, a series of isostructural octahedral hexairon clusters are shown to display spin ground states varying from S = 9/2 to S = 11, marking thus the record of the highest spin states that remain isolated up to 300 K. Such behavior is attributed to double exchange manifested in the strongly delocalized clusters. Consequences of the latter are the hyperfine splitting of the Mössbauer spectrum at low temperature and the emergence of SMM behavior. As seen in the structural metrics, the existence of magnetic anisotropy can be predicted by the asymmetry of the [Fe6] octahedron and further manipulated by simple solvation of the cluster. The latter provides a pathway by which the magnetic behavior can be tuned and enhanced by simple exploration of other auxiliary ligands.