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)

/pdf/the-chemistry-of-graphene-oxide-507zcedhhu.pdf

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

Gezielte Versuche zur Synthese neuer Halogenochalkogen(IV)-Sauren fuhrten mit Tellur und Brom zu den neuen Verbindungen [H3O(Benzo-18-Krone-6)]2[Te2Br10] (1) und [H5O2(Dibenzo-24-Krone-8)]2[Te2Br10] (2). Die [Te2Br10]2--Anionen bestehen aus zwei kantenverknupften verzerrten TeBr6-Oktaedern, die Oxoniumkationen werden durch Kronenether stabilisiert. (1) kristallisiert in der monoklinen Raumgruppe P21/n mit a = 14, 520(5) A, b = 22, 259(6) A, c = 16, 053(5) A, β = 97, 76(3)° und Z = 4, wahrend fur (2) die trikline Raumgruppe mit a = 11, 005(4) A, b = 12, 103(5) A, c = 14, 951(6) A, α = 71, 61(3)°, β = 69, 17(3)°, γ = 68, 40(3)° und Z = 1 gefunden wurde.



Novel Halogenochalcogeno(IV) Acids: [H3O(Benzo-18-Crown-6)]2[Te2Br10] and [H5O2(Dibenzo-24-Crown-8)]2[Te2Br10]



Systematic studies on halogenochalcogeno(IV) acids containing tellurium and bromine led to the new crystalline phases [H3O(Benzo-18-Crown-6)]2[Te2Br10] (1) and [H5O2(Dibenzo-24-Crown-8)]2[Te2Br10] (2). The [Te2Br10]2- anions consists of two edge-sharing distorted TeBr6 octahedra, the oxonium cations are stabilized by crownether. (1) crystallizes in the monoclinic space group P21/n with a = 14.520(5) A, b = 22.259(6) A, c = 16.053(5) A, β = 97.76(3)° and Z = 4, whereas (2) crystallizes in the triclinic space group with a = 11.005(4) A, b = 12.103(5) A, c = 14.951(6) A, α = 71.61(3)°, β = 69.17(3)°, γ = 68.40(3)° and Z = 1.

Neue Halogenochalkogen(IV)-Säuren: [H3O(Benzo-18-Krone-6)]2[Te2Br10] und [H5O2(Dibenzo-24-Krone-8)]2[Te2Br10]†

The reaction of (n-Bu4N)2(M0207] with PhzSnClz and (nBu4N)OH in acetonitrile yields (n-Bu4N)2[(Ph2Sn)2(/z-OH)2(/i-Mo04)2]. After recrystallization from dichloromethane/toluene the crystal structure of (n-Bu4N)2[(Ph2Sn)2(/x-OH)20j-MoO4)2] • CH2CI2 (1) has been determined by single-crystal X-ray diffraction. 1 crystallizes in the space group Pbca,mt\\ia = 15.908(3), Ä = 20.477(3), c = 23.146(4) Ä. The anion contains two cis-diphenyltin groups linked together via two hydroxo and two molybdate bridges. The '^O NMR spectrum of 1 is in accord with the solid State structure, exhibiting resonances in the regions assigned to doubly bridging oxygen atoms and to terminal MoO groups, and a resonance corresponding to the /z-OH group. The ' '®Sn Mößbauer spectrum at 4.2 K is consistent with a cis-R2SnX4 group.

Crystal structure and properties of a novel molecular diorganotin molybdate, (n-Bu4N)2[(Ph2Sn)2(μ-OH)2(μ-MoO4)2]·4CH2Cl2

The room temperature modification of Ag8SiS6 is orthorhombic, space group Pna21, with α = 15.024, b = 7.428, c = 10.533 Å, Z = 4. A complete single crystal X-ray structure analysis shows the structure to contain tetrahedral SiS4(4-) units (Si-S 2.094(12) ... 2.130(12) Å) besides isolated sulfide groups coordinated by Ag; the compound may thus be formulated as Ag8(SiS4)(S)2. The coordination of the Ag atoms by sulfur is distorted tetrahedral (Ag-S 2.557...2.757 A), approximately trigonal planar (Ag-S 2.386...2.775 A, with one additional weakly bonded axial S at 2.991 ... 3.330 Å), or linear (Ag-S 2.414... 2.443 Å). Within the (ordered) Ag sublattice the temperature factors are significantly higher than for Si and S, indicating a certain mobility of the Ag atoms. The arrangement of the thiosilicate -sulfide part of the structure is pseudocubic face-centered, showing the close structural relationship to the disordered cubic high temperature modification of Ag8GeTe6.

Zur Kenntnis des Argyrodit-Strukturtyps: Die Kristallstruktur von Ag8SiS6 / The Argyrodite Structure Type : The Crystal Structure of Ag8SiS6

Syntheses, Crystal Structures, and Properties of the Three Novel Perselenoborates RbBSe3, CsBSe3, and TlBSe3 with Polymeric Chain Anions

[Au2Ag4L4]2⊖, [Au2Cu4L4]2⊖, [Au3Cu3L4]2⊖, [Cu4L3]2⊖ und [Ag9L6]3⊖ (L = Ethan‐1,2‐dithiolat) – neue homoleptische Komplexe der Münzmetalle, darunter erste heteronucleare Metallthiolate

Bernt Krebs

Papers

Neue Halogenochalkogen(IV)-Säuren: [H3O(Benzo-18-Krone-6)]2[Te2Br10] und [H5O2(Dibenzo-24-Krone-8)]2[Te2Br10]†

Crystal structure and properties of a novel molecular diorganotin molybdate, (n-Bu4N)2[(Ph2Sn)2(μ-OH)2(μ-MoO4)2]·4CH2Cl2

Zur Kenntnis des Argyrodit-Strukturtyps: Die Kristallstruktur von Ag8SiS6 / The Argyrodite Structure Type : The Crystal Structure of Ag8SiS6

Syntheses, Crystal Structures, and Properties of the Three Novel Perselenoborates RbBSe3, CsBSe3, and TlBSe3 with Polymeric Chain Anions

[Au2Ag4L4]2⊖, [Au2Cu4L4]2⊖, [Au3Cu3L4]2⊖, [Cu4L3]2⊖ und [Ag9L6]3⊖ (L = Ethan‐1,2‐dithiolat) – neue homoleptische Komplexe der Münzmetalle, darunter erste heteronucleare Metallthiolate