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The selective activation of strong sp C-H bonds at mild conditions is a key step in many biological and synthetic transformations, and an unsolved challenge for synthetic chemists. In nature, soluble methane monooxygenase (sMMO) is one representative example of nonheme dinuclear iron-dependent enzymes that activate strong sp C-H bonds by a high-valent diiron(IV) intermediate . To date, synthetic model complexes of sMMO- have shown limited abilities to oxidize strong C-H bonds. In this work, we generated a high-valent Co(μ-O) complex supported by a tetradentate TPA ligand via one-electron oxidation of its Co(μ-O) precursor . Characterization of and using X-ray absorption spectroscopy and DFT calculations showed that both species possess a diamond core structure with a short Co•••Co distance of 2.78 Å. Furthermore, is an EPR active species showing an = 1/2 signal with clear hyperfine splittings originated from the coupling of the Co nuclear spin with the electronic spin. Importantly, is a highly reactive oxidant for sp C-H bonds, and an oxygenation reagent. has the highest rate constant (1.5 M s at -60 C) for oxidizing 9,10-dihydroanthracene (DHA) compared to diamond core complexes of other first-row transition metals including Mn, Fe and Cu reported previously. Specifically, is about 4-5 orders of magnitude more reactive than the diiron analogs Fe(μ-O) and Fe(μ-O) supported by TPA and related ligands. These findings shed light on future development of more reactive approaches for C-H bond activation by bio-inspired dicobalt complexes.
This article was published in the following journal.
Name: Journal of the American Chemical Society
A highly reactive bis-naphthalene tetracarboxylic diimide (bis-NDI) intermediate, , was designed and synthesized for core-expanded NDIs. Based on this intermediate, we achieved 9- and 11-membered core...
In this work we have demonstrated the growth of nanocrystalline diamond on boron nitride ceramic. We measured the zeta potential of the ceramics to select the diamond seeds. Diamond was then grown on ...
We demonstrate a highly efficient, tunable, ∼5 GHz linewidth diamond Raman laser operating at 479 nm. The diamond laser was pumped by a wavelength-tunable intracavity frequency-doubled titaniu...
We report a new family of nickel phosphinidene molecular clusters synthesized from the reaction of bis(1,5-cyclooctadiene)nickel(0) (Ni(COD)2) with organocyclophosphine and trialkylphosphine. We find ...
The reactivity of a bulky -terphenylboronic acid, DmpB(OH) [; Dmp = 2,6-bis(2,4,6-trimethylphenyl)phenyl], toward three different N-heterocyclic carbenes has been examined. The reaction of with 1 equ...
This study is a single-arm, prospective, multi-center study to assess clinical performance of the SHERLOCK 3CG™ Diamond Tip Confirmation System (TCS) with MODUS II software for confirming ...
The body core temperature drops during general anesthesia. To maintain homeostasis, patients require warming measures. Different methods to measure body core temperature exist, which are e...
The purpose of this study is to maintain a comprehensive registry of patients with the rare inherited bone marrow failure syndrome Diamond Blackfan anemia (DBA).
This study compares the efficacy of diamond burs and Gracey curettes in non-surgical periodontal treatment of chronic periodontitis by clinical, microbiological, biochemical parameters and...
This study will determine the safety and possibility of giving the amino acid, leucine, in patients with Diamond Blackfan anemia(DBA)who are on dependent on red blood cell transfusions. ...
A complex of proteins that assemble the SNRNP CORE PROTEINS into a core structure that surrounds a highly conserved RNA sequence found in SMALL NUCLEAR RNA. They are found localized in the GEMINI OF COILED BODIES and in the CYTOPLASM. The SMN complex is named after the Survival of Motor Neuron Complex Protein 1, which is a critical component of the complex.
Diamond. A crystalline form of carbon that occurs as hard, colorless or tinted isomeric crystals. It is used as a precious stone, for cutting glass, and as bearings for delicate mechanisms. (From Grant & Hackh's Chemical Dictionary, 5th ed)
A transcription factor that dimerizes with the cofactor CORE BINDING FACTOR BETA SUBUNIT to form core binding factor. It contains a highly conserved DNA-binding domain known as the runt domain. Runx1 is frequently mutated in human LEUKEMIAS.
A transcription factor that dimerizes with CORE BINDING FACTOR BETA SUBUNIT to form core binding factor. It contains a highly conserved DNA-binding domain known as the runt domain and is involved in genetic regulation of skeletal development and CELL DIFFERENTIATION.
A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).
Biological therapy involves the use of living organisms, substances derived from living organisms, or laboratory-produced versions of such substances to treat disease. Some biological therapies for cancer use vaccines or bacteria to stimulate the body&rs...
Radiology is the branch of medicine that studies imaging of the body; X-ray (basic, angiography, barium swallows), ultrasound, MRI, CT and PET. These imaging techniques can be used to diagnose, but also to treat a range of conditions, by allowing visuali...