Correction: Morales et al. Characterizing Biogenic MnOx Produced by MnB1 and Its Catalytic Activity towards Water Oxidation. 2024, , 171.

"Lauren N [...

Characterizing Biogenic MnOx Produced by MnB1 and Its Catalytic Activity towards Water Oxidation.

Mn-oxidizing microorganisms oxidize environmental Mn(II), producing Mn(IV) oxides. MnB1 is a widely studied organism for the oxidation of manganese(II) to manganese(IV) by a multi-copper oxidase. The biogenic manganese oxides (BMOs) produced by MnB1 and similar organisms have unique properties compared to non-biological manganese oxides.

Effects of the Intramolecular Group and Solvent on Vibrational Coupling Modes and Strengths of Fermi Resonances in Aryl Azides: A DFT Study of 4-Azidotoluene and 4-Azido--phenylmaleimide.

The high transition dipole strength of the azide asymmetric stretch makes aryl azides good candidates as vibrational probes (VPs). However, aryl azides have complex absorption profiles due to Fermi resonances (FRs). Understanding the origin and the vibrational modes involved in FRs of aryl azides is critically important toward developing them as VPs for studies of protein structures and structural changes in response to their surroundings.

Buffer Effects in Zirconium-Based UiO Metal-Organic Frameworks (MOFs) That Influence Enzyme Immobilization and Catalytic Activity in Enzyme/MOF Biocatalysts.

Novel biocatalysts that feature enzymes immobilized onto solid supports have recently become a major research focus in an effort to create more sustainable and greener chemistries in catalysis. Many of these novel biocatalyst systems feature enzymes immobilized onto metal-organic frameworks (MOFs), which have been shown to increase enzyme activity, stability, and recyclability in industrial processes. While the strategies used for immobilizing enzymes onto MOFs can vary, the conditions always require a buffer to maintain the functionality of the enzymes during immobilization.

Chromium(III) Bis-Arylterpyridyl Complexes with Enhanced Visible Absorption via Incorporation of Intraligand Charge-Transfer Transitions.

A series of chromium(III) bis-arylterpyridyl complexes containing intraligand charge-transfer (ILCT) excited states were prepared and characterized. These complexes show significant absorption in the visible region due to the ILCT bands. The ILCT bands are tunable across the UV and visible spectrum via incorporation of electron-withdrawing and electron-donating groups on the aryl ring.

The "Best Catalyst" for Water Oxidation Depends on the Oxidation Method Employed: A Case Study of Manganese Oxides.

Manganese oxides are a highly promising class of water-oxidation catalysts (WOCs), but the optimal MnOx formulation or polymorph is not clear from previous reports in the literature. A complication not limited to MnOx-based WOCs is that such catalysts are routinely evaluated by different methods, ranging from the use of a chemical oxidant such as Ce(4+), photoactive mediators such as [Ru(bpy)3](2+), or electrochemical techniques. Here, we report a systematic study of nine crystalline MnOx materials as WOCs and show that the identity of the "best" catalyst changes, depending on the oxidation method used to probe the catalytic activity.

Oxidation-potential tuning of tungsten-alkylidyne complexes over a 2 V range.

The electrochemistry and electronic structures of over 30 tungsten-alkylidyne compounds of the form W(CR)L(n)L'(4-n)X (R = H, Bu(t), Ph, p-C6H4CCH, p-C6H4CCSiPr(i)3; X = F, Cl, Br, I, OTf, Bu(n), CN, OSiMe3, OPh; L/L' = PMe3, 1/2 dmpe, 1/2 depe, 1/2 dppe, 1/2 tmeda, P(OMe)3, CO, CNBu(t), py), in which the alkylidyne R group and L and X ligands are systematically varied, have been investigated using cyclic voltammetry and density functional theory calculations in order to determine the extent to which the oxidation potential may be tuned and its dependence on the nature of the metal-ligand interactions. The first oxidation potentials are found to span a range of ∼2 V. Symmetry considerations and the electronic-structure calculations indicate that the highest occupied molecular orbital (and redox orbital) is of principal d(xy) orbital parentage for most of the compounds in this series.

Synthesis, structures, bonding, and redox chemistry of ditungsten butadiyne complexes with W[triple bond]C-C[triple bond]W backbones.

Complexes of the form XL(4)W[triple bond]C-C[triple bond]WL(4)X (L = 1/2 dmpe, 1/2 depe, P(OMe)(3); X = Cl, OTf) have been synthesized from (Bu(t)O)(3)WCCW(OBu(t))(3) in two steps via Cl(3)(dme)WCCW(dme)Cl(3), which undergoes facile four-electron reduction in the presence of L. The compounds possess formal d(2)-d(2) electron configurations. The molecular structures of Cl(dmpe)(2)WCCW(dmpe)(2)Cl and Cl{P(OMe)(3)}(4)WCCW{P(OMe)(3)}(4)Cl were determined by X-ray crystallography; bond distances within the backbone are consistent with a W[triple bond]C-C[triple bond]W canonical structure.

Comparison of cysteine and penicillamine ligands in a Co(II) maquette.

l-Penicillamine (Pen) has been investigated as a ligand for metalloprotein design by examining the binding of Co(II) to the sequence NH(2)-KL(Pen)EGG.(Pen)IG(Pen)GA(Pen).GGW-CONH(2).