Bismuth-Polyoxocation Coordination Networks: Controlling Nuclearity and Dimension-Dependent Photocatalysis.

Bismuth-oxocluster nodes for metal-organic frameworks (MOFs) and coordination networks/polymers are less prolific than other families featuring zinc, zirconium, titanium, lanthanides, etc. However, Bi is non-toxic, it readily forms polyoxocations, and its oxides are exploited in photocatalysis. This family of compounds provides opportunity in medicinal and energy applications.

Photoactive Organo-Sulfur Polymers for Hydrogen Generation.

Herein, we report the synthesis of photoactive polymeric organo-sulfur (POS) materials. These polymers absorb light in the ultraviolet/visible and near-infrared region of the solar spectrum, and upon irradiation, they reduce water to hydrogen (H ). The decoration of POS materials with nitrile (-CN) groups is found to be the critical factor for enhanced interactions with the co-catalyst, Ni P, leading to greater H evolution rates compared to the nitrile-free POS material.

NbO, LiNbO, and (Na, K)NbO Thin Films from High-Concentration Aqueous Nb-Polyoxometalates.

Synthesizing functional materials from water contributes to a sustainable energy future. On the atomic level, water drives complex metal hydrolysis/condensation/speciation, acid-base, ion pairing, and solvation reactions that ultimately direct material assembly pathways. Here, we demonstrate the importance of Nb-polyoxometalate (Nb-POM) speciation in enabling deposition of NbO, LiNbO, and (Na, K)NbO (KNN) from high-concentration solutions, up to 2.

Oxo-Cluster-Based Zr/Hf Separation: Shedding Light on a 70-Year-Old Process.

Zirconium and hafnium in the tetravalent oxidation state are considered the two most similar elements on the periodic table, based on their coexistence in nature and their identical solid-state chemistry. However, differentiating solution phase chemistry is crucial for their separation for nuclear applications that exploit the neutron capture of Hf and neutron transparency of Zr. Here we provide molecular level detail of the multiple factors that influence Zr/Hf separation in a long-exploited, empirically designed industrial solvent-extraction process that favors Hf extraction into an organic phase.

Snapshots of Ce Toroid Assembly from Solids and Solution.

Crystallization at the solid-liquid interface is difficult to spectroscopically observe and therefore challenging to understand and ultimately control at the molecular level. The Ce-torroid formulated [Ce(OH)(O)(SO)(HO)], part of a larger emerging family of M-materials (M = Zr, U, Ce), presents such an opportunity. We elucidated assembly mechanisms by the X-ray scattering (small-angle scattering and total scattering) of solutions and solids as well as crystallizing and identifying fragments of Ce by single-crystal X-ray diffraction.

Structural convergence properties of amorphous InGaZnO from simulated liquid-quench methods.

The study of structural properties of amorphous structures is complicated by the lack of long-range order and necessitates the use of both cutting-edge computer modeling and experimental techniques. With regards to the computer modeling, many questions on convergence arise when trying to assess the accuracy of a simulated system. What cell size maximizes the accuracy while remaining computationally efficient? More importantly, does averaging multiple smaller cells adequately describe features found in bulk amorphous materials? How small is too small? The aims of this work are: (1) to report a newly developed set of pair potentials for InGaZnO and (2) to explore the effects of structural parameters such as simulation cell size and numbers on the structural convergence of amorphous InGaZnO.

Aqueous tantalum polyoxometalate reactivity with peroxide.

Peroxide ligation of aqueous metal-oxo clusters provides rich speciation and structural diversity, radiation sensitivity for manipulation with light, and both broadens and shifts pH-range stability. Here we demonstrate peroxide ligation of the polyoxometalate (POM) [TaO]. We study in detail solution speciation of the peroxide-substituted cluster, and benchmark it to the peroxide-ligated niobate analogue, [NbO(OH)(O)], whose solid-state structure has been reported.

Synthesis and solid-state structural characterization of a series of aqueous heterometallic tridecameric group 13 clusters.

The synthesis and solid-state characterization of a complete series of new heterometallic aqueous nanoscale Ga/In tridecameric clusters is presented. These hydroxo-aquo species significantly expand the library of discrete, aqueous group 13 clusters. This report details the synthetic and structural characterization of these compounds, which are of interest as precursors (inks) for thin-film oxides with materials applications.