The ferrous dithiolato carbonyl Fe(S(2)C(3)H(6))(CO)(2)(dppe) (1) condenses with NiCl(2)(dppe) to give [FeNi(pdt)(mu-Cl)(CO)(dppe)(2)]BF(4) ([2Cl](+)). corresponding reaction of the ditosylate Ni(OTs)(2)(dppe) gave dication [(CO)(2)(dppe)Fe(pdt)Ni(dppe)](OTs)(2) ([2(CO)](OTs)(2)) (pdt = 1,3-propanedithiolate; dppe 1,2-C(2)H(4)(PPh(2))(2); OTs(-) CH(3)C(6)H(4)-4-SO(3)(-)). Reduction bimetallic dicarbonyl borohydride salts afforded impure, thermally stable hydride,...

Abstract In 1976, the first attempted synthesis of saddle‐shaped molecule [8]circulene was reported. The next 37 years produced no advancement towards construction this complicated molecule. But remarkably, over last six months, a flurry progress has been made with two groups reporting independent and strikingly different strategies for derivatives. Herein, we present third synthetic method, in which target tetrabenzo[8]circulene. Our approach employs Diels–Alder reaction palladium‐catalyzed...

This investigation examines the protonation of diiron dithiolates, exploiting new family exceptionally electron-rich complexes Fe(2)(xdt)(CO)(2)(PMe(3))(4), where xdt is edt (ethanedithiolate, 1), pdt (propanedithiolate, 2), and adt (2-aza-1,3-propanedithiolate, 3), prepared by photochemical substitution corresponding hexacarbonyls. Compounds 1-3 oxidize near -950 mV vs Fc(+/0). Crystallographic analyses confirm that 1 2 adopt C(2)-symmetric structures (Fe-Fe = 2.616 2.625 Å, respectively)....

Advances in genome sequencing and bioinformatics methods have identified a myriad of biosynthetic gene clusters (BGCs) encoding uncharacterized molecules. By mining genomes for BGCs containing prevalent peptide-binding domain used the biosynthesis ribosomally synthesized post-translationally modified peptides (RiPPs), we uncovered new compound class involving modifications installed by cytochrome P450, multinuclear iron-dependent non-heme oxidative enzyme (MNIO, formerly DUF692), cobalamin- radical

Cu complexes of 2,2′-dipicolylamine (DPA) were prepared and tested as electrocatalysts for the oxygen reduction reaction (ORR). To study effect multinuclearity on ORR, two Cu–DPA units connected with a flexible linker, third metal-binding pocket was installed in ligand framework. ORR onset potentials diffusion-limited current densities di- tricopper DPA derivatives found to be comparable those simpler system. Electrochemical analyses, crystallographic data, metal-substitution studies...

New derivatives of 2-hydroxypyridine (2-hpH) and Cp*Ir(III) are described. Under conditions for catalytic dehydrogenation 1-phenylethanol catalyzed by Cp*IrCl(κ2-2-hp) (1), the main species observed [Cp*2Ir2H2(2-hp)]Cl ([2]Cl) Cp*IrHCl(κ1-2-hpH) (3). Crystallographic analysis confirms that cation in [2]PF6 consists a Cp*2Ir2(μ-H)x2+ core complemented pyridonate ligand bridges via O N centers. Although [2]Cl is catalytically highly active, related salt not. Addition chloride sources...

Described are new derivatives of the type [HNiFe(SR)2(diphosphine)(CO)3]+, which feature a Ni(diphosphine) group linked to Fe(CO)3 by two bridging thiolate ligands. Previous work had described [HNiFe(pdt)(dppe)(CO)3]+ ([1H]+) and its activity as catalyst for reduction protons (J. Am. Chem. Soc.2010, 132, 14877). Work in this paper focuses on effects properties NiFe model complexes diphosphine attached nickel well dithiolate bridge, 1,3-propanedithiolate (pdt) vs 1,2-ethanedithiolate (edt). A...

Alkyne metathesis provided an efficient macrocyclization route to a cycloparaphenyleneacetylene derivative in high yield. The cavity size was suitably matched for C70 which tightly bound induced-fit fashion. strained alkynes enabled copper-free, 3-fold azide-alkyne cycloaddition at 50 °C.

Well-defined metal nanocrystals play important roles in various fields, such as catalysis, medicine, and nanotechnology. They are often synthesized through kinetically controlled process colloidal systems that contain precursors surfactant molecules. The chemical functionality of surfactants coordinating ligands to ions however remains a largely unsolved problem this process. Understanding the metal-ligand complexation its effect on formation kinetics at molecular level is challenging but...

The characterization of high-valent iron centers in enzymes has been aided by synthetic model systems that mimic their reactivity or structural and spectral features. For example, the cleavage dioxygen often produces an iron(IV)-oxo characterized a number enzymatic systems. In non-heme 2-oxogluterate dependent (iron-2OG) enzymes, ferryl species abstracts H-atom from bound substrate to produce proposed iron(III)-hydroxo caged radical. Most iron-2OG perform radical rebound hydroxylation at...

The thioester Ph2PC6H4-2-C(O)SPh reacts with Fe2(CO)9 to give [Ph2PC6H4C(O)]Fe(SPh)(CO)3, a model for the CO-inhibited active site of enzyme Hmd. This species, which reversibly decarbonylates diiron derivative, cyanide [[Ph2PC6H4C(O)]Fe(SPh)(CN)(CO)2]−.

Fluorine-19 MRI is an emerging cellular imaging approach, enabling lucid, quantitative "hot-spot" with no background signal. The utility of 19F-MRI to detect inflammation and cell therapy products in vivo could be expanded by improving the intrinsic sensitivity probe molecular design. We describe a metal chelate based on salicylidene-tris(aminomethyl)ethane core, solubility perfluorocarbon (PFC) oils, potent accelerator 19F longitudinal relaxation time (T1). Shortening T1 can increase image...

Active site mimics of [FeFe]-hydrogenase are shown to be bidirectional catalysts, producing H2 upon treatment with protons and reducing equivalents. This reactivity complements the previously reported oxidation by these same catalysts in presence oxidants. The complex Fe2(adtBn)(CO)3(dppv)(PFc*Et2 ) ([1]0; adtBn = (SCH2)2NBn, dppv cis-1,2-bis(diphenylphosphino)ethylene, PFc*Et2 Et2PCH2C5Me4FeCp*) reacts excess [H(OEt2)2]BArF4 (BArF4- B(C6H3-3,5-(CF3)2)4-) give ∼0.5 equiv...

Porous materials provide a plethora of technologically important applications that encompass molecular separations, catalysis, and adsorption. The majority research in this field involves network solids constructed from multitopic constituents that, when assembled either covalently or ionically, afford macromolecular arrangements with micro- meso-porous apertures. Recently, porous fabricated discrete organic cages have garnered much interest due to their ease handling solution...

In the dynamic synthesis of covalent organic frameworks and molecular cages, typical synthetic approach involves heuristic methods discovery. While this has yielded many remarkable products, ability to predict structural outcome subjecting a multitopic precursor chemistry (DCC) remains challenge in field. The cages is prime example phenomenon, where precursors designed with intention affording specific product may deviate dramatically when DCC attempted. As such, rational design principles...

Reported are complexes of the formula Fe(dithiolate)(CO)2(diphos) and their use to prepare homo- heterobimetallic dithiolato derivatives. The starting iron dithiolates were prepared by a one-pot reaction FeCl2 CO with chelating diphosphines dithiolates, where dithiolate = S2(CH2)22– (edt2–), S2(CH2)32– (pdt2–), S2(CH2)2(C(CH3)2)2– (Me2pdt2–) diphos cis-C2H2(PPh2)2 (dppv), C2H4(PPh2)2 (dppe), C6H4(PPh2)2 (dppbz), C2H4[P(C6H11)2]2 (dcpe). incorporation 57Fe into such building block commenced...

Co and Fe dihalide complexes of a new rigidly planar PNN ligand platform are prepared examined as precatalysts for hydrosilylation alkenes. Lithiation Thummel's 8-bromo-2-(pyrid-2′-yl)quinoline followed by treatment with (i-Pr)2PCl (C6F5)2PCl afforded the phosphine-quinoline-pyridine ligands, abbreviated RPQpy R = i-Pr C6F5, respectively. These ligands form 1:1 adducts dichlorides dibromides iron cobalt. Crystallographic characterization FeBr2(iPrPQpy), FeBr2(ArFPQpy), CoCl2(iPrPQpy),...

[reaction: see text] A highly efficient stereoselective synthesis of unusual alpha-silylamines via a direct silyl anion addition reaction is reported. This approach convergent and avoids any problematic aza-Brook shifts the anionic intermediates. The use enantiopure tert-butanesulfinyl imines as electrophiles affords exceedingly high levels diastereocontrol for newly formed stereogenic carbon.

This study develops synthetic strategies for N,N-trans and N,N-cis Re(O)(LO–N)2Cl complexes investigates the effects of coordination spheres ligand structures on ancillary exchange dynamics catalytic perchlorate reduction activities corresponding [Re(O)(LO–N)2]+ cations. The 2-(2′-hydroxyphenyl)-2-oxazoline (Hhoz) 2-(2′-hydroxyphenyl)-2-thiazoline (Hhtz) ligands are used to prepare homoleptic isomers both Re(O)(hoz)2Cl Re(O)(htz)2Cl one heteroleptic Re(O)(hoz)(htz)Cl. Selection hoz/htz...

Abstract Macrocycles are unique molecular structures extensively used in the design of catalysts, therapeutics and supramolecular assemblies. Among all reactions reported to date, systems that can produce macrocycles high yield under reaction concentrations rare. Here we report use dynamic hindered urea bond (HUB) for construction with very efficiency. Mixing equal molar diisocyanate diamine leads formation discrete nearly quantitative yields concentration reactants. The bulky N - tert...

The compound K2Cu3US5 was obtained by the reaction of K2S, UCl4, CuCl, and S at 973 K. crystallizes in a new structure type space group Cmcm orthorhombic system cell dimensions = 3.9374(6) Å, b 13.813(2) c 17.500(3) V 951.8(2) Å3 153 comprises [UCu3S52-] slabs separated K+ cations. are built from CuS4 tetrahedra US6 octahedra. Their connectivity differs other known octahedral/tetrahedral packing patterns. In temperature range 130−300 K exhibits Curie−Weiss magnetic behavior with μeff 2.45(8)...

Abstract A new motif for infinite metal atom wires with tunable compositions and properties is developed based on the connection between paddlewheel square planar complex moieties. Two Pd chain compounds, [Pd 4 (CO) (OAc) Pd(acac) 2 ] 1 (TFA) , an PdPt heterometallic compound, Pt(acac) 3 are identified by single‐crystal X‐ray diffraction analysis. In these structures, moiety a four‐membered ring coordinated bridging carboxylic ligands μ carbonyl ligands. The either or...

This study describes the structural, spectroscopic, and electrochemical properties of electronically unsymmetrical diiron hydrides. The terminal hydride Cp*Fe(pdt)Fe(dppe)(CO)H ([1(t-H)]0, Cp*- = Me5C5-, pdt2- CH2(CH2S-)2, dppe Ph2PC2H4PPh2) was prepared by reduction [Cp*Fe(pdt)Fe(dppe)(CO)(NCMe)]+. As established X-ray crystallography, [1(t-H)]0 features a ligand. Unlike previous examples hydrides, does not isomerize to bridging [1(μ-H)]0. Oxidation gives [1(t-H)]+, which also characterized...