The high affinity of Ag+ for DNA bases has enabled creation of short oligonucleotide-encapsulated Ag nanoclusters without formation of large nanoparticles. Time-dependent formation of cluster sizes ranging from Ag1 to Ag4/oligonucleotide were observed with strong, characteristic electronic transitions between 400 and 600 nm. The slow nanocluster formation kinetics enables observation of specific aqueous nanocluster absorptions that evolve over a period of 12 h. Induced circular dichroism bands confirm that the nanoclusters are associated with the chiral ss-DNA template. Fluorescence, absorption, mass, and NMR spectra all indicate that multiple species are present, but that their creation is both nucleotide- and time-dependent.

DNA-templated Ag nanocluster formation.

In this (tutorial overview) perspective we highlight the use of “redox non-innocent” ligands in catalysis. Two main types of reactivity in which the redox non-innocent ligand is involved can be specified: (A) The redox active ligand participates in the catalytic cycle only by accepting/donating electrons, and (B) the ligand actively participates in the formation/breaking of substrate covalent bonds. On the basis of these two types of behavior, four main application strategies of redox-active ligands in catalysis can be distinguished: The first strategy (I) involves oxidation/reduction of the ligand to tune the electronic properties (i.e., Lewis acidity/basicity) of the metal. In the second approach (II) the ligand is used as an electron reservoir. This allows multiple-electron transformations for metal complexes that are reluctant to such transformations otherwise (e.g., because the metal would need to accommodate an uncommon, high-energy oxidation state). This includes examples of (first row) transition ...

Redox Non-Innocent Ligands: Versatile New Tools to Control Catalytic Reactions

Prepared within biocompatible poly(amidoamine) dendrimer hosts, blue emitting Au8 nanodots were prepared with fluorescence quantum yields more than 100 times larger than any previously prepared. The strong size-dependent blue emission from these from monodisperse Au8 nanodots was measured to be 41% in aqueous solution and 52% in methanol. These easily prepared, water-soluble, and high quantum yield gold nanodots lend insight into the molecular nature of small metal nanoclusters and may find application as novel biocompatible fluorophores.

High quantum yield blue emission from water-soluble Au8 nanodots

Easily observed on the single molecule level, highly fluorescent and photostable silver nanoclusters have been photochemically prepared within poly(amidoamine) dendrimer hosts in aqueous solutions. The dendrimer cage stabilizes and solubilizes the nanoclusters to yield highly stable, photoactivated single nanodots ranging in size from 2 to 8 silver atoms. These multicolored, highly fluorescent species are extremely photostable and readily observed on the single molecule scale with weak mercury lamp excitation. Such easily created, bright, photoactivated water-soluble fluorophores are likely to greatly expand the impact of single molecule labeling studies in a wide variety of systems.

Individual Water-Soluble Dendrimer-Encapsulated Silver Nanodot Fluorescence

Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C(2)H(2)/C(2)H(4) have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C(2)H(2) and C(2)H(4). The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C(2)H(2)/C(2)H(4).

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Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene

The complex Ni[S2C2(CF3)2]2reacts with light olefins, including ethylene and propylene, selectively and reversibly. The reaction is not poisoned by hydrogen gas, carbon monoxide, acetylene, or hydrogen sulfide, which are commonly present in olefin streams, presumably because olefin binding occurs through the sulfur ligand rather than the metal center. The reversible reaction of olefins with Ni[S2C2(CN)2]2 n ( n = 0, −1, −2) can be controlled electrochemically, where the oxidation state–dependent binding and release of olefins are fast on the electrochemical time scale. The observed tolerance to poisons and controllable electrochemical reactivity present an alternative approach to the separation of olefins from complex streams.

https://science.sciencemag.org/content/sci/291/5501/106.full.pdf

Toward Separation and Purification of Olefins Using Dithiolene Complexes: An Electrochemical Approach

Disclosed herein is a process for producing phenol. The process includes oxidizing at least a portion of a feed comprising cyclohexylbenzene to produce an oxidation composition comprising cyclohexyl-1-phenyl-1-hydroperoxide. The oxidation composition may then be cleaved in the presence of an acid catalyst to produce a cleavage reaction mixture comprising the acid catalyst, phenol and cyclohexanone. At least a portion of the cleavage reaction mixture may be neutralized with a basic material to form a treated cleavage reaction mixture. In various embodiments, the treated cleavage reaction mixture contains no greater than 50 wppm of the acid catalyst or no greater than 50 wppm of the basic material.

Process for producing phenol

A variety of new and known transition metal dithiolene complexes has been synthesized from thiometalates via induced internal electron-transfer reactions. Treating MS42- (M = Mo, W) with stoichiometric amounts of bis(trifluoromethyl)-1,2-dithiete ((CF3)2C2S2) results in rapid formation of the respective tris(dithiolene) complexes M(tfd)32- (tfd = [(CF3)2C2S2]2-). These complexes are isostructural and adopt twisted trigonal prismatic coordination (ca. 18° from a perfect trigonal prism). Crystal data:  Mo(tfd)32-, monoclinic, space group C2/c, with a = 18.905(4) A, b = 13.732(3) A, c = 17.101(3) A, β = 110.29(3)°, and Z = 4; W(tfd)32-, monoclinic, space group C2/c, with a = 18.933(4) A, b = 13.728(3) A, c = 17.096(3) A, β = 110.26(3)°, and Z = 4. In contrast, Mo(tfd)3 (synthesized as reported previously) has nearly perfect trigonal prismatic coordination. Crystal data:  hexagonal, space group P63/m, with a = 9.6795(14) A, b = 9.6795(14) A, c = 13.951(3) A, and Z = 2. Treating WOS32- and MoO2S22- with (CF3)2...

Syntheses of metal dithiolene complexes from thiometalates by induced internal redox reactions

This invention is directed to the production of olefin product high in ethylene and propylene content using synthesis gas (syngas) as a feed The syngas is converted to an intermediate composition high in methanol and dimethyl ether using a catalyst of at least two catalyst components, the first including at least one metal oxide and the second including at least one molecular sieve The intermediate composition is then contacted with an olefin forming catalyst to form the olefin product

Producing olefin product from syngas

A process for converting light paraffins (especially C 3 - C 5 ) to middle distillate and higher boiling range liquid hydrocarbons by (1 ) oxygen or air oxidation of iso-paraffins to alkyl hydroperoxides; (2) conversion of alkyl hydroperoxides to dialkyl peroxides; (3) radical coupling of paraffins using the dialkyl peroxides as radical initiators forming heavier hydrocarbon products; and (4) fractionation of the heavy hydrocarbon products. The net reaction is catalytically converting light paraffins to heavier hydrocarbons using oxygen or air to effect the conversion.

Kun Wang

Papers

Toward Separation and Purification of Olefins Using Dithiolene Complexes: An Electrochemical Approach

Process for producing phenol

Syntheses of metal dithiolene complexes from thiometalates by induced internal redox reactions

Producing olefin product from syngas

Upgrading paraffins to distillates and lubricant basestocks