High-Valent Cobalt-Difluoride in Oxidative Fluorination of Saturated Hydrocarbons.

The heme paradigm where Fe=O acts as the C-H oxidant and Fe-OH rebounds with the formed carbon-centered radical guides the design of the prototypical synthetic hydroxylation catalyst. We are exploring methods to evolve beyond the metal-oxo oxidant and hydroxide rebound, to incorporate a wider array of functional group. We have demonstrated the application of Co(OTf) (10 mol% catalyst; OTf=trimfluoromethanesulfonate) in combination with polydentate N-donor ligands (e.

A Structural and Functional Mimic of P680.

One or multiple chlorophyll a molecules are employed in the reaction center of photosystem II's main electron donor (defined as P680). We have a poor understanding of how the reaction center facilitates water oxidation in photosystem II and the roles that mono- and/or multimeric chlorophyll groups play when P680 oxidizes a neighboring tyrosine in order to drive water oxidation at the oxygen evolving complex. We have prepared a dimeric Mg-porphyrin complex [Mg(BTPP)] (1, H-BTPP=1,2-bis-(10,15,20-triphenylporphyrin-5-yl)-benzene) as a structural and functional mimic of the dimeric core of P680.

Secondary Coordination Sphere Influences the Formation of Fe(III)-O or Fe(III)-OH in Nitrite Reduction: A Synthetic and Computational Study.

The reduction of nitrite (NO) to generate nitric oxide (NO) is a significant area of research due to their roles in the global nitrogen cycle. Here, we describe various modifications of the tris(5-cyclohexyliminopyrrol-2-ylmethyl)amine H[N(pi)] ligand where the steric bulk and acidity of the secondary coordination sphere were explored in the non-heme iron system for nitrite reduction. The cyclohexyl and 2,4,6-trimethylphenyl variants of the ligand were used to probe the mechanism of nitrite reduction.

The role of lithium in the osteogenic bioactivity of clay nanoparticles.

LAPONITE® clay nanoparticles are known to exert osteogenic effects on human bone marrow stromal cells (HBMSCs), most characteristically, an upregulation in alkaline phosphatase activity and increased calcium deposition. The specific properties of LAPONITE® that impart its bioactivity are not known. In this study the role of lithium, a LAPONITE® degradation product, was investigated through the use of lithium salts and lithium modified LAPONITE® formulations.

Interplay between gelation and phase separation in aqueous solutions of methylcellulose and hydroxypropylmethylcellulose.

Thermally induced gelation in aqueous solutions of methylcellulose (MC) and hydroxypropylmethylcellulose (HPMC) has been studied by rheological, optical microscopy, and turbidimetry measurements. The structural and mechanical properties of these hydrogels are dominated by the interplay between phase separation and gelation. In MC solutions, phase separation takes place almost simultaneously with gelation.