Author
John R. Blackburn
Bio: John R. Blackburn is an academic researcher from Vanderbilt University. The author has contributed to research in topics: X-ray photoelectron spectroscopy & Amino acid. The author has an hindex of 5, co-authored 9 publications receiving 324 citations.
Papers
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206 citations
70 citations
33 citations
TL;DR: In this paper, a study of the equilibria involving nickel(II) and equimolar amounts of different optically active amino acids was conducted, and it was shown that in such systems the mixed complexes, MAB, are favored to a greater extent than would be predicted from statistical considerations alone.
22 citations
TL;DR: In this article, a search for stereoselectivity in the hydrolysis of an optically active amino acid ester (histidine methyl ester) when catalyzed by nickel(II) complexes of active amino acids was conducted.
6 citations
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TL;DR: In contrast to the conventional Pd/C catalyst, graphite oxide and graphene-based catalysts gave much higher activities with turnover frequencies exceeding 39,000 h(-1), accompanied by very low palladium leaching (<1 ppm).
Abstract: Pd2+-exchanged graphite oxide and chemically derived graphenes therefrom were employed as supports for Pd nanoparticles. The influence of catalyst preparation, carbon functionalization, and catalyst morphology on the catalytic activity in the Suzuki−Miyaura coupling reactions was investigated. The catalysts were characterized by means of spectroscopy (FT-IR, solid-state 13C NMR, AAS, XPS), X-ray scattering (WAXS), surface area analysis (BET, methylene blue adsorption), and electron microscopy (TEM, ESEM). In contrast to the conventional Pd/C catalyst, graphite oxide and graphene-based catalysts gave much higher activities with turnover frequencies exceeding 39 000 h−1, accompanied by very low palladium leaching (<1 ppm).
1,113 citations
TL;DR: It is shown that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure, and thus improves its prospects for nanoelectronic applications.
Abstract: Functionalization of atomically thin nanomaterials enables the tailoring of their chemical, optical and electronic properties. Exfoliated black phosphorus (BP)-a layered two-dimensional semiconductor-exhibits favourable charge-carrier mobility, tunable bandgap and highly anisotropic properties, but it is chemically reactive and degrades rapidly in ambient conditions. Here we show that covalent aryl diazonium functionalization suppresses the chemical degradation of exfoliated BP even after three weeks of ambient exposure. This chemical modification scheme spontaneously forms phosphorus-carbon bonds, has a reaction rate sensitive to the aryl diazonium substituent and alters the electronic properties of exfoliated BP, ultimately yielding a strong, tunable p-type doping that simultaneously improves the field-effect transistor mobility and on/off current ratio. This chemical functionalization pathway controllably modifies the properties of exfoliated BP, and thus improves its prospects for nanoelectronic applications.
669 citations
TL;DR: In this article, a reusable heterogeneous nanopalladium (0) catalysts were used for coupling products by C-C bond formation reaction of haloarenes that include unreactive chloroarenes in the presence of base.
Abstract: The present invention relates to a novel process for the preparation of a reusable heterogeneous nanopalladium (0) catalysts, which is a eco-friendly and economical process employing re-usable heterogeneous catalyst in place of soluble palladium catalysts for preparing coupling products by C—C bond formation reaction of haloarenes that include unreactive chloroarenes in the presence of base. The use of heterogeneous nanopalladium catalyst precludes the presence of palladium in traces with the product.
666 citations
TL;DR: It is found that one-dimensional growth could be induced and maintained through an interplay of the following processes: speedy reduction of the precursor to ensure prompt addition of atoms to the seed; chemisorption of bromide on the seed to promote the formation of {100} and {110} facets.
Abstract: This paper describes a simple and versatile method for growing highly anisotropic nanostructures of Pd, single-crystal nanobars bounded by {100} facets and single-crystal nanorods with their side surfaces enclosed by {100} and {110} facets. According to thermodynamic arguments, Pd atoms should nucleate and grow in a solution phase to form cuboctahedrons of spherical shape with their surfaces bounded by a mix of {111} and {100} facets. Anisotropic nanostructures can only form under kinetically controlled conditions, while the cubic symmetry is broken. In the present system, we found that one-dimensional growth could be induced and maintained through an interplay of the following processes: (i) speedy reduction of the precursor to ensure prompt addition of atoms to the seed; (ii) chemisorption of bromide on the seed to promote the formation of {100} and {110} facets; and (iii) localized oxidative etching on one specific face of the seed to initiate preferential growth on this face. Experimentally, the anisotropic growth can be achieved by varying the type and concentration of reducing agent, as well as by adjusting the reaction temperature. This methodology developed for Pd has also been extended to both Au and Pt. As expected for a kinetically controlled product, the anisotropic nanostructure evolved into the thermodynamically favored shape during an aging process.
554 citations
TL;DR: In this article, the X-ray photoelectron spectra of some forty-six copper compounds and complexes have been measured and the chemical shifts obtained from accurate determinations of the binding energies have been qualitatively explained on the basis of the Pauling electronegativity concept using the group electrophoresis of Huheey for the polyatomic counter anions.
Abstract: The X-ray photoelectron spectra of some forty-six copper compounds and complexes have been measured. The chemical shifts obtained from accurate determinations of the binding energies have been qualitatively explained on the basis of the Pauling electronegativity concept using the group electronegatives of Huheey for the polyatomic counter anions. The chemical shifts of the copper atoms as well as the atoms in the ligands were found to be dependent not only on the oxidation state but also on the kind and number of ligand atoms. Intense satellite lines were found in the 2p and 2s bands of the cupric compounds; the number and splitting of the satellites were found to be sensitive to the chemical environment. A correlation was found between the satellite splitting and the binding energies and this is explained by a 3d→4s, 4p ‘shake-up’ mechanism.
447 citations