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 halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.

The Halogen Bond

In 1981, the macrocyclic methylene-bridged glycoluril hexamer (CB[6]) was dubbed "cucurbituril" by Mock and co-workers because of its resemblance to the most prominent member of the cucurbitaceae family of plants--the pumpkin. In the intervening years, the fundamental binding properties of CB[6]-high affinity, highly selective, and constrictive binding interactions--have been delineated by the pioneering work of the research groups of Mock, Kim, and Buschmann, and has led to their applications in waste-water remediation, as artificial enzymes, and as molecular switches. More recently, the cucurbit[n]uril family has grown to include homologues (CB[5]-CB[10]), derivatives, congeners, and analogues whose sizes span and exceed the range available with the alpha-, beta-, and gamma-cyclodextrins. Their shapes, solubility, and chemical functionality may now be tailored by synthetic chemistry to play a central role in molecular recognition, self-assembly, and nanotechnology. This Review focuses on the synthesis, recognition properties, and applications of these unique macrocycles.

The cucurbit[n]uril family

Iron Catalysis in Organic Synthesis

The Golden Age of Transfer Hydrogenation

The first well-defined iron-based catalyst system for the reduction of nitroarenes to anilines has been developed applying formic acid as reducing agent. A broad range of substrates including other reducible functional groups were converted to the corresponding anilines in good to excellent yields at mild conditions. Notably, the process constitutes a rare example of base-free transfer hydrogenations.

General and Selective Iron-Catalyzed Transfer Hydrogenation of Nitroarenes without Base

Chemoselective cubes: Cubane-type [Mo(3)S(4)X(3)(dmpe)(3)](+) clusters (dmpe = 1,2-(bis)dimethylphosphinoethane), in combination with an azeotropic 5:2 mixture of HCOOH and NEt(3) as the reducing agent, act as selective cluster catalysts (X = H) or precatalysts (X = Cl) for the transfer hydrogenation of functionalized nitroarenes, without the formation of hazardous hydroxylamines.

Chemoselective transfer hydrogenation to nitroarenes mediated by cubane-type Mo3S4 cluster catalysts.

An ab initio theoretical study of the optical absorption spectrum of Ni2+‐doped MgO has been conducted by means of calculations in a MgO‐embedded (NiO6)10−cluster. The calculations include long‐ and short‐range embedding effects of electrostatic and quantum nature brought about by the MgO crystalline lattice, as well as electron correlation and spin–orbit effects within the (NiO6)10− cluster. The spin–orbit calculations have been performed using the spin–orbit‐CI WB‐AIMP method [Chem. Phys. Lett. 147, 597 (1988); J. Chem. Phys. 102, 8078 (1995)] which has been recently proposed and is applied here for the first time to the field of impurities in crystals. The WB‐AIMP method is extended in order to handle correlation effects which, being necessary to produce accurate energy differences between spin–free states, are not needed for the proper calculation of spin–orbit couplings. The extension of the WB‐AIMP method, which is also aimed at keeping the size of the spin–orbit‐CI within reasonable limits, is base...

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Ab initio model potential calculations on the electronic spectrum of Ni2+‐doped MgO including correlation, spin–orbit and embedding effects

Transition metal cluster chalcogenides with cubane-type structures are relevant to our understanding of several industrial and biological catalytic processes. Recent advances in cluster chemistry owe much to the development of rational synthetic approaches, an aspect that is emphasised in this review which focuses on cuboidal clusters of molybdenum and tungsten (M) with M2M′2S4 and M3M′Q4 (Q = S, Se) central units that incorporate a first-row transition metal atom (M′). Special attention has been paid to the non-aqueous chemistry of these compounds. The structural features of these complexes are discussed in relation to their electronic structures within the framework of molecular orbital theory, spectroscopic, magnetic and electrochemical experimental data. Finally, the importance of these clusters in catalysis, nonlinear optics and in the formation of supramolecular adducts is discussed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Heterodimetallic Chalcogen‐Bridged Cubane‐Type Clusters of Molybdenum and Tungsten Containing First‐Row Transition Metals

The mononuclear PPh4[Fe(phen)(CN)4]·2H2O (1) complex and the cyanide-bridged bimetallic [{Fe(phen)(CN)4}2M(H2O)2]·4H2O compounds [M = Mn(II) (2) and Zn(II) (3); phen = 1,10-phenanthroline; PPh4 = tetraphenylphosphonium cation] have been synthesized and structurally and magnetically characterized. Complex 1 crystallizes in the monoclinic system, space group P21/c, with a = 9.364(4) A, b = 27.472(5) A, c = 14.301(3) A, β = 97.68(2)°, and Z = 4. Complexes 2 and 3 are isostructural and they crystallize in the monoclinic system, space group P21/n, with a = 7.5292(4) A, b = 15.6000(10) A, c = 15.4081(9) A, β = 93.552(2)°, and Z = 2 for 2 and a = 7.440(1) A, b = 15.569(3) A, c = 15.344(6) A, β = 93.63(2)°, and Z = 2 for 3. The structure of complex 1 is made up of mononuclear [Fe(phen)(CN)4]- anions, tetraphenyphosphonium cations, and water molecules of crystallization. The iron(III) is hexacoordinate with two nitrogen atoms of a chelating phen (2.018(6) and 2.021(6) A for Fe−N) and four carbon atoms of four term...

[Fe(Phen)(CN)4]-: a versatile building block for the design of heterometallic systems. Crystal structures and magnetic properties of PPh4[Fe(Phen)(CN)4]*2H2O and [[Fe(Phen)(CN)4]2M(H2O)2]*4H2O [Phen = 1,10-phenanthroline; M = Mn(II) and Zn(II)].

Rosa Llusar

Papers

General and Selective Iron-Catalyzed Transfer Hydrogenation of Nitroarenes without Base

Chemoselective transfer hydrogenation to nitroarenes mediated by cubane-type Mo3S4 cluster catalysts.

Ab initio model potential calculations on the electronic spectrum of Ni2+‐doped MgO including correlation, spin–orbit and embedding effects

Heterodimetallic Chalcogen‐Bridged Cubane‐Type Clusters of Molybdenum and Tungsten Containing First‐Row Transition Metals

[Fe(Phen)(CN)4]-: a versatile building block for the design of heterometallic systems. Crystal structures and magnetic properties of PPh4[Fe(Phen)(CN)4]2H2O and [[Fe(Phen)(CN)4]2M(H2O)2]4H2O [Phen = 1,10-phenanthroline; M = Mn(II) and Zn(II)].