The chemistry of graphene oxide is discussed in this critical review Particular emphasis is directed toward the synthesis of graphene oxide, as well as its structure Graphene oxide as a substrate for a variety of chemical transformations, including its reduction to graphene-like materials, is also discussed This review will be of value to synthetic chemists interested in this emerging field of materials science, as well as those investigating applications of graphene who would find a more thorough treatment of the chemistry of graphene oxide useful in understanding the scope and limitations of current approaches which utilize this material (91 references)

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The chemistry of graphene oxide

Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

The hydrogen bond is the most important of all directional intermolecular interactions. It is operative in determining molecular conformation, molecular aggregation, and the function of a vast number of chemical systems ranging from inorganic to biological. Research into hydrogen bonds experienced a stagnant period in the 1980s, but re-opened around 1990, and has been in rapid development since then. In terms of modern concepts, the hydrogen bond is understood as a very broad phenomenon, and it is accepted that there are open borders to other effects. There are dozens of different types of X-H.A hydrogen bonds that occur commonly in the condensed phases, and in addition there are innumerable less common ones. Dissociation energies span more than two orders of magnitude (about 0.2-40 kcal mol(-1)). Within this range, the nature of the interaction is not constant, but its electrostatic, covalent, and dispersion contributions vary in their relative weights. The hydrogen bond has broad transition regions that merge continuously with the covalent bond, the van der Waals interaction, the ionic interaction, and also the cation-pi interaction. All hydrogen bonds can be considered as incipient proton transfer reactions, and for strong hydrogen bonds, this reaction can be in a very advanced state. In this review, a coherent survey is given on all these matters.

The hydrogen bond in the solid state.

The transition metal dichalcogenides are about 60 in number. Two-thirds of these assume layer structures. Crystals of such materials can be cleaved down to less than 1000 A and are then transparent in the region of direct band-to-band transitions. The transmission spectra of the family have been correlated group by group with the wide range of electrical and structural data available to yield useful working band models that are in accord with a molecular orbital approach. Several special topics have arisen; these include exciton screening, d-band formation, and the metal/insulator transition; also magnetism and superconductivity in such compounds. High pressure work seems to offer the possibility for testing the recent theory of excitonic insulators.

The transition metal dichalcogenides discussion and interpretation of the observed optical, electrical and structural properties

Copper is an essential trace element in living systems, present in the parts per million concentration range. It is a key cofactor in a diverse array of biological oxidation-reduction reactions. These involve either outer-sphere electron transfer, as in the blue copper proteins and the Cu{sub A} site of cytochrome oxidase and nitrous oxide redutase, or inner-sphere electron transfer in the binding, activation, and reduction of dioxygen, superoxide, nitrite, and nitrous oxide. Copper sites have historically been divided into three classes based on their spectroscopic features, which reflect the geometric and electronic structure of the active site: type 1 (T1) or blue copper, type 2 (T2) or normal copper, and type 3 (T3) or coupled binuclear copper centers. 428 refs.

Multicopper Oxidases and Oxygenases

The catecholase activity of the dicopper(II) complexes [Cu2(L1)(μ-OCH3)(NCCH3)2](PF6)2·H2O·CH3CN (1), [Cu2(L2)(μ-OH)(MeOH)(NCCH3)](BF4)2 (2), [Cu2(L3)(μ-OMe)(NCCH3)2](BF4)2·2CH3CN·H2O (3), [Cu2(L2)(μ-OAc)2]BF4·H2O (4), [Cu2(L4)(μ-OAc)2]ClO4 (5) and [Cu2(L5)(μ-OMe)(NCCH3)3(OH2)](ClO4)2·2CH3OH·CH3CN (6) consisting of varying para-substituted phenol ligands HL1 = 4-trifluoromethyl-2,6-bis((4-methylpiperazin-1-yl)methyl)phenol, HL2 = 4-bromo-2,6-bis((4-methyl-1,4-diazepan-1-yl)methyl)phenol, HL3 = 4-bromo-2-((4-methyl-1,4-diazepan-1-yl)methyl)-6-((4-methylpiperazin-1-yl)methyl)phenol, HL4 = 2,6-bis((4-methylpiperazin-1-yl)methyl)-4-nitrophenol and HL5 = 4-tert-butyl-2,6-bis((4-methylpiperazin-1-yl)methyl)phenol was studied. The main difference within the six complexes lies in the individual copper–copper separation that is enforced by the chelating side arms of the phenolate ligand entity and more importantly in the exogenous bridging solvent, hydroxide, methanolate or acetate ions. The distance between the copper cores varies from 2.94A in 1 to 3.29A in 5. The catalytic activity of the complexes 1–6 towards the oxidation of 3,5-di-tert-butylcatechol was determined spectrophotometrically by monitoring the increase of the 3,5–di-tert-butylquinone characteristic absorption band at about 400 nm over time saturated with O2. The complexes are able to oxidize the substrate 3,5-di-tert-butylcatechol to the corresponding o-quinone with distinct catalytic activity (kcat between 92 h−1 and 189 h−1), with an order of decreasing activity 6 > 5 > 1, 2, 4 ≥ 3. A kinetic treatment of the data based on the Michaelis-Menten approach was applied. A correlation of the catecholase activities with the variation of the para- substituents as well as other effects resulting from the copper core distances is discussed. [Cu2(L5)(μ-OMe)(NCCH3)3(OH)2](ClO4)2·2CH3OH·CH3CN (6) exhibited the highest activity of the six complexes as a result of its high turnover rate.

Altering the Activity of Catechol Oxidase Model Compounds by Electronic Influence on the Copper Core

Regio‐Directed Synthesis of a ZnIIFeIII Complex from an Unsymmetrical Ligand and Its Relevance to Purple Acid Phosphatases

An Unsymmetrical Dinuclear Iron(III) Complex with Peroxidase Properties

Hexanuclear copper(II) complex of a novel poly(pyridine) ligand exhibiting unique long distance ferromagnetic interactions through a nitrato-O,O′ bridge

Bernt Krebs

Papers

Altering the Activity of Catechol Oxidase Model Compounds by Electronic Influence on the Copper Core

Regio‐Directed Synthesis of a ZnIIFeIII Complex from an Unsymmetrical Ligand and Its Relevance to Purple Acid Phosphatases

An Unsymmetrical Dinuclear Iron(III) Complex with Peroxidase Properties

Hexanuclear copper(II) complex of a novel poly(pyridine) ligand exhibiting unique long distance ferromagnetic interactions through a nitrato-O,O′ bridge

Crystal and molecular structure of bis(N-benzoylglycinato)triaquozinc(II) dihydrate