Chlorophyll-based pigments are crucial mediators of redox processes in photosynthesis, serving as the primary electron donors in photosystems I and II. Despite their structural similarities, these pigments exhibit a wide range of redox potentials (0.5–1.3 V vs SHE), and little experimental insight into the origins of this variation is available. To address this deficit, we have synthesized two crown ether-appended Mg-porphyrin complexes as chlorophyll model compounds and demonstrated their ability to bind redox-inactive metal cations. Cation binding to the Mg-porphyrin complexes was found to increase their redox potentials in a manner that depends linearly on the total cationic charge felt by the complex, implicating a through-space electrostatic field effect. The corresponding 1-electron oxidized π-cation radical complexes were then prepared and characterized by UV–vis, FT-IR, and EPR spectroscopies and ESI-MS. The π-cation radical species were found to be competent for the PCET oxidation of a phenolic substrate, mimicking the reaction between photo-oxidized chlorophyll and tyrosine in photosystem II. Cation binding to the π-cation radical complexes was found to increase the rates of their PCET and ET reactions in a charge-dependent manner which could be rationalized using Marcus theory. This work provides direct experimental evidence that electrostatic fields can tune the redox potentials of chlorophyll model compounds, leading to an increase in their oxidative reactivity.

Budget plan would kill two CDC journals, while U.S. prosecutor accuses some nongovernmental publications of being “partisans”

A major thrust of research in modern main group chemistry is the use of multidentate ligands to perturb geometries at p-block elements such that they deviate substantially from valence shell electron-...

Abstraction of bromide from a B-brominated phosphaborene stabilized by a cyclic alkylamino carbene results in the formation of a transient cationic phosphaborene, which undergoes intramolecular C−H a....

NMR crystallography has blossomed as a focussed field of research in recent years and is now acknowledged as such by the International Union of Crystallogr

In recent years, neutral NHC-stabilized boryl radicals have been investigated as reactive species in various organic transformations. However, cationic boron radicals have been significantly less explored. In addition, boron-centered open-shell species with S > 1/2 have emerged as attractive synthetic targets. In this study, we provide a synthetic route to an NHC-stabilized boryl radical cation as a salt of the weakly coordinating [Al(ORF)4]− (RF = C(CF3)3) anion. The synthetic procedure was extended to dicationic diboron derivatives of Schlenk’s and Thiele’s hydrocarbons with meta- and para-phenylene coupling units between the spin centers. While most known isolable boron biradicals have a singlet ground-state with a thermally accessible triplet state, the boron version of Schlenk’s hydrocarbon occupies a ground-state triplet spin-state, as shown by combined electron paramagnetic resonance spectroscopy and density functional theory studies. Furthermore, initial reactivity studies of the dications with elemental sulfur and diphenyldiselenide are presented.

We have developed C6F5BH2·SMe2 as a unique, metal-free precatalyst for alkene hydroboration. It combines high reactivity and excellent regio- and chemoselectivity. Mechanistic studies reveal that the ...

Although several inorganic analogues of cyclopentadiene have been reported with group-15 elements, examples featuring the heavier elements Sb and Bi remain scarce. Now, a Bi5 ring has been stabilized ...

Plastic consumption in seabirds causes blood signatures of widespread organ damage including brain, stomach, kidney, and liver.

The ubiquity of N-heterocyclic carbenes (NHCs) in chemical research typically arises from their potent stabilizing capabilities and role as innocent spectators to stabilize otherwise non-bottleable co...

The University of Prince Edward Island offers an amazing and affordable student experience in beautiful Charlottetown, PEI. Our interesting and unique programs bring out your best, lead you to realize...

The ozonolytic deconstruction of aromatics remains a challenge in organic chemistry. Ozone preferentially reacts with alkenes over arenes, meaning that once the initial aromatic cleavage occurs, the d...

We present the synthesis and characterization of the parent isolable monomeric triplet titanocene complex, stabilized by the N-heterocyclic carbene (NHC) IMe4. Investigated by SQUID magnetometry and q...

A potent squaramide-based anion transporter was used to evaluate how vesicles prepared with tailored lipid compositions, which mimic organelle membranes, can impact transmembrane transport. Using HPTS...

Main group radical chemistry has been a targeted research area for several decades. With growing examples of phosphorus radicals, heavier pnictogen radicals including arsenic, antimony, and bismuth ha...

A Florida State University faculty member has been elected to a prestigious scientific organization for his innovation in magnetic resonance, a scientific

In this study, we have employed high-resolution charge density (HRCD) techniques using X-ray diffraction data collected at 10 K to reanalyze the intermetallic electron density topologies of two repres...