The trigonal-bipyramidal high-spin (S = 2) oxoiron(IV) complex [FeIV(O)(TMG2dien)(CH3CN)]2+ (7) was synthesized and spectroscopically characterized. Substitution of the CH3CN ligand by anions, demonstrated here for X N3– Cl–, yielded additional S 2 complexes general formulation [FeIV(O)(TMG2dien)(X)]+ (7-X). reduced steric bulk 7 relative to published [FeIV(O)(TMG3tren)]2+ (2) reflected enhanced rates intermolecular substrate oxidation.

An "end-on" Ni2+-superoxo adduct has been prepared via two independent synthetic routes and its structure ascertained by spectroscopic computational methods. The new type in nickel coordination chemistry is supported resonance Raman EPR features, the former displaying a high frequency nu (O-O) mode (1131 cm-1) consistent with significant superoxo character. oxidizes PPh3 to OPPh3 quantitative yield.

We have generated a high-spin FeIII–OOH complex supported by tetramethylcyclam via protonation of its conjugate base and characterized it in detail using various spectroscopic methods. This species can be converted quantitatively to an FeIV═O O–O bond cleavage; this is the first example such conversion. conversion promoted two factors: strong bond, which inhibits Fe–O lysis, addition protons, facilitates cleavage. provides synthetic precedent for how cleavage FeIII–peroxo intermediates...

We report that redox-inactive Sc(3+) can trigger O2 activation by the Fe(II)(TMC) center (TMC = tetramethylcyclam) to generate corresponding oxoiron(IV) complex in presence of BPh4(-) as an electron donor. To model a possible intermediate above reaction, we generated unprecedented adduct [Fe(III)(η(2)-O2)(TMC)](+) alternative route, which was found have Fe(3+)-(μ-η(2):η(2)-peroxo)-Sc(3+) core and convert complex. These results important implications for role Lewis acid play facilitating O-O...

Oxoiron(V) species are postulated to be involved in the mechanisms of arene cis -dihydroxylating Rieske dioxygenases and bioinspired nonheme iron catalysts for alkane hydroxylation, olefin -dihydroxylation, water oxidation. In an effort obtain a synthetic oxoiron(V) complex, we report herein one-electron oxidation S = 1 complex [Fe IV (O)(TMC)(NCCH 3 )] 2+ ( , where TMC is tetramethylcyclam) by treatment with tert -butyl hydroperoxide strong base acetonitrile generate metastable 2 at -44 °C,...

The apparent Sc3+ adduct of [FeIV(O)(TMC)]2+ (1, TMC = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized in amounts sufficient to allow its characterization by various spectroscopic techniques. Contrary the earlier assignment a +4 oxidation state for iron center 1, we establish that 1 high-spin iron(III) based on Mössbauer and EPR spectra quantitative reduction equiv ferrocene [FeII(TMC)]2+. Thus, is best described as ScIII–O–FeIII complex, agreement with previous...

We report the first conjugate acid–base pair of nonheme oxoiron(<sc>iv</sc>) complexes, which are supported by a tetramethylcyclam ligand with pendant amide that binds <italic>trans</italic> to oxo group <italic>via</italic> carbonyl oxygen.

The spring of 2020 saw the spread COVID-19 throughout world, and in response many colleges universities moved to emergency remote instruction. Herein is described how an introductory chemistry course that prioritizes active learning collaboration was adapted for learning. Instructors used both asynchronous synchronous instruction continued with revised group activities. A Distance Learning Pod allowed students distant time zones work collaboratively even when they could not participate Rates...

Nanorods of EuO, a concentrated magnetic semiconductor, are synthesized. SQUID magnetometry shows large ferromagnetic response for the nanorods 6.9 μB per europium atom. Magnetic circular dichroism verifies that nanowires indeed and semiconducting.

Activation of elemental sulfur by the monovalent nickel complex [PhTt (tBu)]Ni(CO) [PhTt(tBu)=phenyl{tris[(tert-butylmethyl)thio]methyl}borate] generates disulfidodinickel(II) 2. This species is alternatively accessible via thermal decomposition (tBu)]Ni(SCPh3). Spectroscopic, magnetic, and X-ray diffraction studies establish that 2 contains a mu-eta(2):eta(2)-S2 ligand fosters antiferromagnetic exchange coupling between Ni (II) ions. observation in contrast to lighter congener, oxygen,...

We report the generation and spectroscopic characterization of a heterobimetallic [(TMC)Fe(III)-O-Cr(III)(OTf)4] species (1) by bubbling O2 into mixture Fe(TMC)(OTf)2 Cr(OTf)2 in NCCH3. Complex 1 also formed quantitatively adding to [Fe(IV)(O)(TMC)(NCCH3)](2+). The proposed activation mechanism involves trapping Cr-O2 adduct Fe(TMC)(OTf)2.

Nucleophilic oxidant: The reaction between a thiolato iron(II) complex 1 and superoxide in aprotic solvent at −90 °C yields novel iron(III) peroxide intermediate 2, which exhibits unusually high nucleophilic reactivity. Compound 2 is an isomer of the that invoked reductase superoxide.

Cobalt Kβ valence-to-core X-ray emission spectroscopy features are shown to be influenced by the ligand spectrochemical series.

Reduction of elemental sulfur by a monovalent nickel precursor leads to trans-1,2-μ-disulfidodinickel(II) complex assigned based on combination advanced spectroscopic methods in conjunction with density functional theory calculations. The disulfido linkage is characterized an intense optical S → Ni charge transfer transition at 650 nm, which causes significant distortion the Ni2S2 core along isotope-sensitive v(S−S) mode 474 cm−1, as demonstrated resonance Raman excitation profile this...

Insights and methods from the chemical sciences are directly relevant to global challenges such as climate change, renewable energy generation storage, water purification, food production. However, these connections often opaque students in general chemistry courses, who may get lost weeds of stoichiometry, VSEPR, gas laws, fail see relevance their studies lives communities. Herein we describe a redesigned first-year undergraduate course that grounds content societal applications. Students...

The electronic structures of a series high-spin Ni(II)-thiolate complexes the form [PhTttBu]Ni(SR) (R = CPh3, 2; C6F5, 3; C6H5, 4; PhTttBu phenyltris((tert-butylthio)methyl)borate) have been characterized using combined spectroscopic and computational approach. Resonance Raman (rR) data reveal that νNi−SR vibrational feature occurs between 404 436 cm−1 in these species. corresponding rR excitation profiles display striking de-enhancement behavior because interference effects involving...

Methyl-coenzyme M reductase (MCR) catalyzes the final step in methane biosynthesis by methanogenic archaea and contains a redox-active nickel tetrahydrocorphin, coenzyme F430, at its active site. Spectroscopic computational methods have been used to study novel form of coenzyme, called F330, which is obtained reducing F430 with sodium borohydride (NaBH4). F330 exhibits prominent absorption peak 330 nm, blue shifted 100 nm relative F430. Mass spectrometric studies demonstrate that...

A powerful means of enhancing our understanding the structures and functions enzymes that contain nickel−sulfur bonds, such as Ni superoxide dismutase, acetyl-coenzyme synthase/carbon monoxide dehydrogenase, [NiFe] hydrogenase, methyl-CoM reductase, involves investigation model compounds with similar structural and/or electronic properties. In this study, we have characterized a trans-μ-1,2-disulfido-bridged dinickel(II) species, [{(tmc)Ni}2(S2)]2+ (1, tmc =...

Nucleophiles Oxidans: Die Reaktion eines Thiolatoeisen(II)-Komplexes 1 mit Superoxid in aprotischem Solvens bei −90 °C ergibt ein neuartiges Thiolatoeisen(III)-Peroxid-Intermediat 2 ungewöhnlich hoher Nucleophilie. ist Isomer des Thiolatoeisen(II)-Superoxid-Intermediats der von Superoxid-Reduktase Superoxid.

In this study, a combined spectroscopic and computational approach has been employed to generate detailed description of the electronic structure binuclear side-on disulfido (Ni(II))(2) complex, [{(PhTt(tBu))Ni}(2)(mu-eta(2):eta(2)-S(2))] (1, where PhTt(tBu) = phenyltris[(tert-butylthio)methyl]borate). The disulfido-to-Ni(II) charge-transfer transitions that dominate absorption spectrum have assigned on basis time-dependent density functional theory (DFT) calculations. Resonance Raman...

The tetraazamacrocyclic ligand 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane (TMC) has been used to bind a variety of first-row transition metals but date the crystal structure cobalt(II) complex missing from this series. cobalt chlorido(1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane-κ 4 N )cobalt(II) chloride dihydrate, [CoCl(C 14 H 32 )]Cl·2H 2 O or [Co II Cl(TMC)]Cl·2H O, crystallizes as purple crystal. This species adopts distorted square-pyramidal geometry in which TMC...