"Naked" metal nanoparticles (NPs) are thermodynamically and kinetically unstable in solution. Ligands, surfactants, or polymers, which adsorb at a particle's surface, can be used to stabilize NPs; however, such mode of stabilization is undesirable for catalytic applications because the adsorbates block surface active sites. The activity stability NPs usually inversely correlated. Here, we describe an example bimetallic (PtFe) NP catalyst stabilized by carboxylate ligands that bind...

Molybdenum complexes with the general formula Mo(NR)(CHR')(OR″)(Cl)(MeCN) (R = t-Bu or 1-adamantyl; OR″ a 2,6-terphenoxide) recently have been found to be highly active catalysts for cross-metathesis reactions between Z-internal olefins and Z-1,2-dichloroethylene Z-(CF3)CH═CH(CF3). In this paper we report methods of synthesizing new potential M(NR)(CHR')(OR″)(Cl)(L) in which M Mo W, NR N-2,6-diisopropylphenyl NC6F5, L is phosphine, pyridine, nitrile. We also test compare all cyclooctene. Our...

A novel synthetic protocol toward imidazo[1,2-a]quinoxalines has been developed. It includes two isocyanide-based multicomponent reactions sequentially introducing four diversity elements to the final products.

We describe an enzyme-inspired catalytic system based on a rationally designed multifunctional amphiphile. The resulting micelles feature metal-binding sites and stable free radical moieties as well fluorous pockets that attract preconcentrate molecular oxygen. In the presence of copper ions, effect chemoselective aerobic alcohol oxidation under ambient conditions in water, transformation is challenging to achieve nonenzymatically.

Addition of one equiv water to Mo(CAr)[OCMe(CF3)2]3(1,2-dimethoxyethane) (2, Ar = o-(OMe)C6H4) in the presence PPhMe2 leads formation Mo(O)(CHAr)[OCMe(CF3)2]2(PPhMe2) (3(PPhMe2)) 34% yield. alone 2 produces dimeric alkylidyne hydroxide complex, {Mo(CAr)[OCMe(CF3)2]2(μ-OH)}2(dme) (4(dme)) which each bridging proton points toward an oxygen atom arylmethoxy group. PMe3 4(dme) gives alkylidene oxo (3(PMe3)), analogue 3(PPhMe2) (95% conversion, 66% isolated). Treatment 3(PMe3) with two HCl gave...

Abstract Developing well‐defined iron‐based catalysts for olefin metathesis would be a breakthrough achievement in the field not only to replace existing by inexpensive metals but also attain new reactivity taking advantage of unique electronic structure base metals. Here, we present two‐coordinate homoleptic iron complex, Fe(HMTO) 2 [HMTO=O‐2,6‐(2,4,6‐Me 3 C 6 H ) ], that is capable performing ring‐opening polymerization norbornene produce highly stereoregular polynorbornene (99 % cis,...

Abstract Aptamers are promising biorecognition elements for sensors. However, aptamer‐based assays often lack the requisite levels of sensitivity and/or selectivity because they typically employ structure‐switching aptamers with attenuated affinity utilize reporters that require aptamer labeling or which susceptible to false positives. Dye‐displacement offer a label‐free, sensitive means overcoming these issues, wherein target binding liberates dye is complexed aptamer, producing an optical...

We have successfully achieved selective and efficient functionalization of sheet edges in microcrystalline multilayer γ-graphyne through two methods: cross-coupling with residual bromide edge groups copper-catalyzed azide-alkyne cycloaddition (CuAAC) terminal alkyne groups. This modification significantly enhances the ease mechanical exfoliation dispersibility sheets γ-graphyne. Specifically, C

The reaction between Mo(O)(CHAro)(ORF6)2(PMe3) (Aro = ortho-methoxyphenyl, ORF6 OCMe(CF3)2) and 2 equiv of LiOHMT (OHMT O-2,6-(2,4,6-Me3C6H2)2C6H3) leads to Mo(O)(CHAro)(OHMT)2, an X-ray structure which shows it be a trigonal bipyramidal anti benzylidene complex in the o-methoxy oxygen is coordinated metal trans apical oxo ligand. Addition 1 water (in THF) benzylidyne complex, Mo(CArp)(OR)3(THF)2 (Arp para-methoxyphenyl, OR or OC(CF3)3 (ORF9)) formation {Mo(CArp)(OR)2(μ-OH)(THF)}2(μ-THF)...

Vanadium bis-phosphine imido and oxo chloride alkylidenes have been extensively applied in the ring-closing metathesis of various acyclic olefins. However, their reactions involving ethylene shown limited productivity due to rapid decomposition. The primary degradation pathway V complexes is β-H elimination at an unsubstituted metallacyclobutane. In contrast, disfavored for species, but bimolecular decomposition precludes its high productivity. Herein, we present synthesis NHC that are most...

An approach for supporting a Pd-NHC complex on soluble star polymer with nanoscale dimensions is described. The resulting catalyst exhibits excellent activity in cross-coupling reactions, stable air and moisture, easily recoverable recyclable. These properties are distinct unattainable the small-molecule version of same catalyst.

A strategy for arraying nanoparticles (NPs) on mesoporous supports modified with functional self-assembled monolayers is described. Au NPs supported materials containing thiols exhibited thermal stability and catalytic competency well beyond that of unsupported, thiol-protected similar size.

Reactions between Mo(N-t-Bu)2(CH2-t-Bu)2 or Mo(NAdamantyl)2(CH2CMe2Ph)2 and 3 equiv of HCl in the presence 1 PPh2Me yield Mo(NR)(CHR′)(PPh2Me)Cl2 complexes, from which Mo(NR)(CHR′)(PPh2Me)(OAr)Cl complexes (OAr = a 2,6-terphenoxide) can be prepared. The were evaluated as cross-metathesis catalysts cyclooctene Z-1,2-dichloroethylene. efficiencies test reaction for OAr OTPP, OHMT, OHIPT, OHTBT (where OTPP is 2,3,5,6-tetraphenylphenoxide, OHMT hexamethylterphenoxide, OHIPT...

A new chemical series was identified via high-throughput screening as having antiproliferative activity on DU-145 human prostate carcinoma cell line (hit compound potency - 2.9 microM). Medicinal chemistry optimization of two peripheral diversity vectors the hit molecule, independently, led to SAR generalizations and identification 'best' moieties. The latter were merged in a single that exhibited an over 100-fold better than compound. For most potent compounds it confirmed observed not...

We describe a family of star block-copolymers rationally designed for enzyme-inspired catalysis alcohol oxidation in water.

A "double benzyne" reaction between 1,3-dichloro-2-iodobenzene and 2,4,6-t-Bu

V imido alkylidenes have been applied for the ring-opening metathesis polymerization involving cyclic olefins. However, those complexes found limited application in reactions with acyclic terminal olefins due to instability toward ethylene. Experimental and theoretical studies show that β-hydride elimination from unsubstituted metallacyclobutene is primary decomposition pathway systems. Herein, we report synthesis of first catalytically active oxo alkylidene, VO(CHSiMe3)(PEt3)2Cl, which...

In the interest of preparing molybdenum and tungsten alkylidene complexes for olefin metathesis that are longer-lived at high temperatures (∼150 °C or above), we synthesized contain a phenoxide ligand with 2-pyridyl in one ortho position mesityl (Mes) 2,4,6-i-Pr3C6H2 (Trip) other ([MesON]− [TripON]−, respectively). The (neophylidene) were prepared include W(O)(CHCMe2Ph)(Me2Pyr)(RON) (R = Mes Trip), Mo(NC6F5)(CHCMe2Ph)(RON)Cl, Mo(N-2,6-Me2C6H3)(CHCMe2Ph)(RON)Cl, Mo(N-t-Bu)(CHCMe2Ph)(RON)Cl,...

Abstract Vanadium‐based catalysts have shown activity and selectivity in ring‐opening metathesis polymerization of strained cyclic olefins comparable to those Ru, Mo, W catalysts. However, the application V alkylidenes routine organic synthesis is limited. Here, we present first example ring‐closing olefin catalyzed by well‐defined chloride alkylidene phosphine complexes. The developed exhibit tolerance various functional groups, such as an ether, ester, a tertiary amide, amine, sulfonamide....

Abstract Developing well‐defined iron‐based catalysts for olefin metathesis would be a breakthrough achievement in the field not only to replace existing by inexpensive metals but also attain new reactivity taking advantage of unique electronic structure base metals. Here, we present two‐coordinate homoleptic iron complex, Fe(HMTO) 2 [HMTO=O‐2,6‐(2,4,6‐Me 3 C 6 H ) ], that is capable performing ring‐opening polymerization norbornene produce highly stereoregular polynorbornene (99 % cis,...

We have successfully achieved selective and efficient functionalization of sheet edges in microcrystalline multilayer γ-graphyne through two methods: cross-coupling with residual bromide edge groups, copper-catalyzed azide-alkyne cycloaddition (CuAAC) terminal alkyne groups. This modification significantly enhances the ease mechanical exfoliation dispersibility sheets γ-graphyne. Specifically, C18-grafted forms stable dispersions compatible organic solvents, allowing for imaging atomically...

Preserving vanadium in a high oxidation state during chemical transformations can be challenging due to the oxidizing nature of V(+5) species. Oxo and similar isoelectronic ligands have been utilized stabilize by extensive π-donation. However, decreasing bond order between V oxo ligand often results reduction metal center. Herein, we report unique transformation involving anionic alkylidene that converts complex alkylidyne three steps without altering This method has used obtain rare 3d...

We describe a system in which the self-replication of micellar aggregates results spontaneous amplification chirality reaction products. In this system, amphiphiles are synthesized from two "clickable" fragments: water-soluble "head" and hydrophobic "tail". Under biphasic conditions, is autocatalytic, as facilitate transfer molecules to aqueous phase. When chiral, partially enantioenriched surfactant heads used, strong nonlinear induction products observed. Preseeding mixture with an...