bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal and Species Engineering with Semi‐Flexible Nitrogen Containing Organic Cations: Generation of [H13O6]+Ions with the Unfavoured Unbranched Topology by Enclosing Hydrochloric Acid in a Porous Inorganic‐Organic Hybrid Material
Authors: Graf J. , Frank Walter 
Published: October 2004

AbstractThe reaction of rhodium(III) chloride trihydrate with 1, 4‐diazacycloheptane in concentrated hydrochloric acid results in the formation of tris(1, 4‐diazoniacycloheptane) hexaaquahydrogen(1+) bis(hexachlororhodate(III)) chloride, [C5H14N2]3[H13O6][RhCl6]2Cl (1). Dark red crystals of1are obtained by diffusion‐controlled crystallization at room temperature. Slow evaporation of the mother liquor over a period of several days yields a few tiny crystals of the bis(1, 4‐diazoniacycloheptane) hexachlororhodate(III) chloride hydrate, [C5H14N2]2[RhCl6]Cl˙1.75 H2O (2), as red thin squared plates. In the context of crystal engineering, compounds1and2are inorganic‐organic hybrid materials built up from octahedral [RhCl6]3‐, simple Cl‐and semi‐flexible heterocyclic 1, 4‐diazoniacycloheptane ions, incorporating either the [H13O6]+and further Cl‐ions or portions of simple water molecules. Both compounds crystallize in the space group typeP21/c. Compound1contains isolated [H13O6]+ions with a linear chain‐like configuration enclosed in the cavities of the inorganic‐organic framework. The presence of a strong central O···H···O hydrogen bond within the [H13O6]+ions in1is confirmed by the short O···O separation of 2.47Å and by characteristic IR absorption bands at 1626 (s), ∼ 1250 (m) and 668 (m) cm‐1. During the thermal decomposition, compound1looses at first five equivalents of water and one equivalent of hydrochloric acid in a two‐step process at 37 °C and 67 °C. This is followed by the decomposition of the 1, 4‐diazoniacycloheptane cations and the hexachlororhodate(III) anions, starting at 190 °C and proceeding intensified at 240 °C.
The Henicosaphosphide Iodides of Potassium and Rubidium, K4P21I and Rb4P21I
Authors: Hönle Wolfgang , Schmettow Walter , Peters Karl , Chang Jen‐Hui , von Schnering Hans Georg 
Published: October 2004

AbstractThe novel ternary polyphosphides M4P21I (M = K, Rb) have been synthesized from the elements in single crystalline form, representing further examples for the formation of mixed crystals between simple salts and binary phosphides. They form as ruby‐red platelets and dark‐red prisms, respectively, and are only slightly sensitive to moisture and oxygen. The compounds are isotypic (Ccmm (no 63); Z = 4; oP104; K4P21I: a = 12.853Å; b = 21.795Å; c = 9.748Å; 1168 hkl, R = 0.033; Rb4P21I: a = 13.281Å; b = 21.868Å; c = 9.771Å; 777 hkl, R = 0.053) and feature corrugated 2D networks formed from two different types of polymerized P7 units. The networks form large cavities filled by M+ and I‐ ions. Zigzag chains of condensed trigonal M6 prisms, centered by the I‐ anions, separate the polyphosphide nets. The mean homoatomic P‐P bond length (d = 2.216Å) corresponds to a P‐P single bond. However, the individual P‐P distances vary with position and function (2.126 ‐ 2.247Å) and these are compared with those of the isolated P21‐3 anion.
Reaktionen eines Dibismutans und von Cyclobismutanen mit Metallcarbonylen ‐ Synthesen von Komplexen mit R2Bi‐, RBi‐, Bi2‐ und Bin‐Liganden (R = Me3CCH2, Me3SiCH2)
Authors: Balázs L. , Breunig H. J. , Lork E. 
Published: October 2004

AbstractReaktionen von [Fe2(CO)9] mit [(Me3CCH2)2Bi]2 oder cyclo‐(Me3SiCH2Bi)n (n = 3 ‐ 5) führen zu den Komplexen [(R2Bi)2Fe(CO)4], [RBiFe(CO)4]2 (R = Me3CCH2, Me3SiCH2) und [Bi2Fe3(CO)9]. [Bi2{Mn(CO)2C5H4CH3}3] entsteht in einer photochemischen Reaktion aus [Mn(CO)3C5H4CH3] und cyclo‐(Me3SiCH2Bi)n.
Synthese und Struktur von Ruthenium(II)‐Komplexen mit Triazenido‐ und Pentaazadienido‐Liganden
Authors: Barboza da Silva Carlos Fernando , Schwarz Simon , Galceran Mestres Montserrat , Teijelo López Sonia , Strähle Joachim 
Published: October 2004

AbstractDer Ruthenium(II)‐triazenido‐Komplex [RuCl(ClC6H4N3C6H4Cl)(p‐Cymol)] (1) entsteht bei der Umsetzung von Silber‐bis(p‐chlorphenyl)triazenid mit [RuCl2(p‐Cymol)]2 in CH2Cl2 in Form luftstabiler, gelboranger Kristalle. Er kristallisiert als 1·CH2Cl2 in der orthorhombischen Raumgruppe Pbca mit den Gitterkonstanten a = 3134, 3(3); b = 2105, 7(2); c = 769, 15(4) pm und Z = 8. Im diamagnetischen Einkernkomplex 1 koordiniert der Triazenidoligand chelatartig mit den Atomen N(1) und N(3). p‐Cymol ist über den C6‐Ring η6‐gebunden. Die Reaktion des Etherphosphan‐Komplexes [RuCl2(Ph2PCH2C4H7O2)2] mit 1, 3‐Bis(p‐tolyl)triazenid in THF ergibt den Komplex [RuCl(tolyl‐N3‐tolyl)(Ph2PCH2C4H7O2)2] (2). Von 2 werden monokline, rote Kristalle mit der Raumgruppe P21/c und a = 1521, 0(2); b = 1451, 8(2); c = 2073, 7(2) pm; β = 99, 29(1)° und Z = 4 erhalten. Im luftstabilen, diamagnetischen Komplex 2 ist das Triazenidion mit seinen Atomen N(1) und N(3) als Chelatligand gebunden. Von den beiden Etherphosphanliganden koordiniert einer chelatartig über das P‐Atom und ein O‐Atom, während der zweite Ligand einzähnig mit seinem P‐Atom bindet, so daß sich für RuII die Koordinationszahl sechs ergibt. [Ag(tolyl‐N5‐tolyl)]2 reagiert in THF mit [RuCl2(C6H6)]2 unter Bildung des an Luft stabilen, diamagnetischen Pentaazadienidokomplexes [RuCl(tolyl‐N5‐tolyl)(C6H6)] (3). 3 bildet monokline, rote Kristalle mit der Raumgruppe P21/c und a = 1462, 4(1); b = 1056, 51(8); c = 1371, 4(1) pm, β = 114, 36(1)° und Z = 4. Der Pentaazadienidoligand koordiniert mit seinen Atomen N(1) und N(3) chelatartig am zweiwertigen Ru‐Atom. Das Benzolmolekül ist über sein π‐System η6‐gebunden.
Polycyclic Phosphorus Sulfide Compounds containing Chiral Amido or Imido Substituents
Authors: Tattershall Bruce W. , Houghton Richard W. , Martin Daniel J. 
Published: October 2004

AbstractReactions of α‐P4S3I2 with (S)‐ or racemic‐RNH2 (R = CH(Me)Ph) have given solutions containing exo, exo‐ or endo, exo‐α‐P4S3(NHR)2, α‐ or β‐P4S3(μ‐NR), or P4S2(μ‐NR), as the first compounds with polycyclic phosphorus sulfide skeletons to contain chiral substituents. The expected diastereomers have been characterised by complete analysis of their 31P{1H} NMR spectra, and relative configuration has been assigned in most cases. Considerable diastereomeric differences in coupling constants and chemical shifts were found.
Complex Formation of 2, 6‐Bis‐(2′‐hydroxyphenyl)pyridine with AlIII, FeIII and CuII
Authors: Steinhauser Stefan , Heinz Uwe , Sander Jürgen , Hegetschweiler Kaspar 
Published: October 2004

AbstractComplex formation of 2, 6‐bis(2′‐hydroxyphenyl)pyridine (H2Li) with Fe3+ and Cu2+ was investigated in a H2O/DMSO medium (mole fraction xDMSO = 0.2) by potentiometric and spectrophotometric methods. The pKa values of [H3Li]+ are 2.25, 10.51 and 14.0 (25 °C, 0.1 M KCl). The formation constants of [FeIII(Li)]+ and [CuII(Li)] (25 °C, 0.1 M KCl) are log β1 = 21.5 for Fe3+ and log β1 = 18.5 for Cu2+. The crystal structures of [Al(Li)2Na(EtOH)3], [Fe(Li)2Na(EtOH)3], and [Cu(Li)(py)]2 were investigated by single‐crystal X‐ray diffraction analyses. The FeIII and the AlIII compound are isotypic and crystallize in the monoclinic space group P21/n. Al‐compound (215 K): a = 12.599(3) Å, b = 16.653(3) Å, c = 17.525(4) Å, β = 100.27(3)°, Z = 4 for C40H40AlN2NaO7; Fe‐compound (293 K): a = 12.753(3) Å, b = 16.715(3) Å, c = 17.493(3) Å, β = 99.68(3)°, Z = 4 for C40H40FeN2NaO7. Both compounds contain a homoleptic, anionic bis‐complex [M(Li)2]‐ of approximate D2 symmetry. The Cu compound crystallized as an uncharged, dinuclear and centrosymmetric [Cu(Li)(py)]2 complex in the monoclinic space group P21/n with (293 K) a = 13.386(3) Å, b = 9.368(2) Å, c = 14.656(3) Å, β = 100.65(3)°, Z = 2 for C44H32Cu2N4O4. The structural properties and in particular the possible influence of the ligand geometry on the stability of the metal complexes is discussed.
1‐Aminoindan‐2‐ol, a Suitable Ligand for the Synthesis of Chiral, Intramolecularly Stabilized Compounds of Aluminum, Gallium, and Indium
Authors: Schumann Herbert , Kaufmann Jens , Dechert Sebastian 
Published: October 2004

AbstractThe reactions of enantiomerically pure (1R, 2S)‐(+)‐cis‐1‐aminoindan‐2‐ol, (1S, 2R)‐(‐)‐cis‐1‐aminoindan‐2‐ol, and racemic trans‐1‐aminoindan‐2‐ol with trimethylaluminum, ‐gallium, and ‐indium produce the intramolecularly stabilized, enantiomerically pure dimethylmetal‐1‐amino‐2‐indanolates (1R, 2S)‐(+)‐cis‐Me2AlO‐2‐C*HC7H6‐1‐C*HNH2 (1), (1S, 2R)‐(‐)‐cis‐Me2AlO‐2C*HC7H6‐1‐C*HNH2 (2), (1R, 2S)‐(+)‐cis‐Me2GaO‐2‐C*HC7H6‐1‐C*HNH2 (3), (1R, 2S)‐(+)‐cis‐Me2InO‐2‐C*HC7H6‐1‐C*HNH2 (4), (1S, 2R)‐(‐)‐cis‐Me2InO‐2‐C*HC7H6‐1‐C*HNH2 (5), and racemic (+/‐)‐trans‐Me2InO‐2‐C*HC7H6‐1‐C*HNH2 (6). The compounds were characterized by 1H NMR, 13C NMR, 27Al NMR and mass spectra as well as 1 and 3 to 6 by determination of their crystal and molecular structures. The dynamic dissociation/association behavior of the coordinative metal‐nitrogen bond was studied by low temperature 1H NMR spectroscopy.
Hexacoordinate Silicon(IV) Complexes with SiO6 Skeletons and Multidentate Ligands Derived from Citric Acid or Malic Acid
Authors: Tacke Reinhold , Bertermann Rüdiger , Burschka Christian , Dragota Simona 
Published: October 2004

AbstractMorpholinium meso‐bis[citrato(3‐)‐O1, O3, O6]silicate (meso‐5) and racemic morpholinium bis[citrato(4‐)‐O1, O3, O6]silicate (rac‐6) were synthesized by treatment of tetramethoxysilane with citric acid and morpholine (molar ratio 1:2:2 and 1:2:4, respectively). Treatment of tetramethoxysilane with (S)‐malic acid and tri(n‐propyl)amine or tri(n‐butyl)amine (molar ratio 1:3:2) yielded tri(n‐propyl)ammonium (Λ, S, S, S)‐mer‐tris[malato(2‐)‐O1, O2]silicate ((Λ, S, S, S)‐mer‐7) and tri(n‐butyl)ammonium (Λ, S, S, S)‐mer‐tris[malato(2‐)‐O1, O2]silicate ((Λ, S, S, S)‐mer‐8). The hexacoordinate silicon compounds meso‐5·2MeOH, rac‐6·1.73MeOH, (Λ, S, S, S)‐mer‐7, and (Λ, S, S, S)‐mer‐8·2MeCN were structurally characterized in the solid state by single‐crystal X‐ray diffraction and VACP/MAS NMR spectroscopy (13C, 15N, 29Si). Upon dissolution in water at 20 °C, spontaneous hydrolysis of the λ6Si‐silicate anions was observed.
Zinkkomplexe eines neuen N, N, O‐Liganden
Authors: Trösch Alexander , Vahrenkamp Heinrich 
Published: October 2004

AbstractDer dreizähnige Ligand N, N(2‐Dimethylaminoethyl)‐3, 5‐di‐tert.‐butyl‐salicylaldimin (LH) bildet sich aus dem entsprechenden Salicylaldehyd und N, N‐Dimethylethylendiamin. Mit Zinksalzen bildet er die einkernigen Halogenokomplexe [LZnCl˙CH3OH] (1) und [LZnI˙CH3OH] (2) und das vermutlich polymere Acetat [LZnOCOCH3] (3). Mit Diethylzink und Phosphorsäurediphenylester entsteht der Phosphatkomplex [LZn‐OPO(OPh)2˙CH3OH] (4). Die zwischen trigonal‐bipyramidal und quadratisch‐pyramidal liegende Koordination der Komplexe und die Art der fünf Donoren im Phosphatkomplex repräsentieren den Übergangszustand der hydrolytischen Substratspaltung in einem Zinkenzym.
Nanostructured ZrO2 and Zr‐C‐N Coatings from Chemical Vapor Deposition of Metal‐Organic Precursors
Authors: Mathur Sanjay , Altmayer Jessica , Shen Hao 
Published: October 2004

AbstractNanocrystalline zirconium carbonitride (Zr‐C‐N) and zirconium oxide (ZrO2) films were deposited by chemical vapor deposition (CVD) of zirconium‐tetrakis‐diethylamide (Zr(NEt2)4) and ‐tert‐butyloxide (Zr(OBut)4), respectively. The films were deposited on iron substrates and characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). The Zr‐C‐N films show blue, golden brown or bronze colours, with colour stability depending upon the precursor composition (pure metal amide or mixed with Et2NH). The deposition temperature showed no pronounced effect on the granular morphology of the Zr‐C‐N films. The XRD data of the films correspond to the formation of carbonitride phase whereas the XPS analyses revealed a strong surface oxidation and incorporation of oxygen in the film. The films deposited using a mixture of Zr(NEt2)4 and Et2NH showed higher N content, better adhesion and scratch resistance when compared to films obtained from the CVD of pure Zr(NEt2)4. Subject to the precursor composition and deposition temperature (550‐750 °C), the microhardness values of Zr‐C‐N films were found to be in the range 2.11‐5.65 GPa. For ZrO2 films, morphology and phase composition strongly depend on the deposition temperature. The CVD deposits obtained at 350 °C show tetragonal ZrO2 to be the only crystalline phase. Upon increasing the deposition temperature to 450 °C, a mixture of tetragonal and monoclinic modifications was formed with morphology made up of interwoven elongated grains. At higher temperatures (550 and 650 °C), pure monoclinic phase was obtained with facetted grains and developed texture.
Hydrogen Bonding in Imidazolium Nitrates [1]
Authors: Kuhn Norbert , Richter Markus , Steimann Manfred , Ströbele Markus , Sweidan Kamal 
Published: October 2004

AbstractThe imidazolium nitrates [ImH](NO3) (1) and [ImBr](NO3) (2) are obtained from the corresponding bromides [ImH]Br (3) and [ImBr]Br (4) and AgNO3 in excellent yields (Im = 2, 3‐dihydro‐1, 3‐diisopropyl‐4, 5‐dimethylimidazol‐2‐ylidene). The crystal structures of 1 and 2 consist of infinite linear chains of ions linked by H···O and Br···O contacts. In addition, stacks consisting of imidazolium and nitrate ions in the sequence ImBr/NO3/ImBr/NO3··· with parallel orientation of their plains are detected in 2. The crystal structure of 3 is also reported.
Experimental Charge Density Studies of Cyclotetrasilazane and Metal Complexes Containing the Di‐ and Tetraanion
Authors: Kocher Nikolaus , Selinka Carola , Leusser Dirk , Kost Daniel , Kalikhman Inna , Stalke Dietmar 
Published: October 2004

AbstractThe homologous series of parent octamethylcyclotetrasilazane (c‐NH‐SiMe2‐)4, (1), the lithium complex [(THF)2Li2(c‐N‐SiMe2‐NH‐SiMe2‐)2]2, (2), containing the cyclic dianion, and [(THF)2LiAl(c‐N‐SiMe2‐)4]2, (3), accommodating the unprecedented tetraanion [Me2SiN]4‐was synthesized to investigate the nature of the covalent Si‐N single bond in the presence of various metals. These model compounds show a wide diversity of Si‐N(H), Si‐N(M), Si‐N(H, M) and M‐N bonds and serve as bench‐mark systems to study polar bonds by high‐resolution low‐temperature X‐ray structure analysis. Experimental charge density studies reveal highly polar Si‐N bonds with remarkable ionic contribution, even in the non‐metallated starting material1. The Li‐N and Li‐O bonds have to be classified as almost purely ionic bonds with topological properties not far from those determined for NaCl.
Synthesis and Crystal Structure of Te6[MCl6] (M = Zr, Hf), Containing a Polymeric Chalcogen Cation (Te62+)n
Authors: Baumann Alexander , Beck Johannes 
Published: October 2004

AbstractThe reaction of tellurium, tellurium tetrachloride, and ZrCl4 or HfCl4, respectively, under the conditions of chemical vapour transport in a temperature gradient 220 → 200 °C yields black crystals of Te6[ZrCl6] and Te6[HfCl6]. While Te6[ZrCl6] is formed almost quantitatively, Te6[HfCl6] is always accompanied by neighbored phases such as Te4[HfCl6] and Te8[HfCl6]. The crystal structures of Te6[ZrCl6] (orthorhombic, Pbcm, a = 1095.4(1), b = 1085.2(1), c = 1324.5(1) pm) and Te6[HfCl6] (a = 1094.8(2), b = 1086.3(2), c = 1325.0(2) pm) are isotypic and consist of one‐dimensional polymeric (Te62+)n cations and of discrete, only slightly distorted octahedral [MCl6]2‐ anions (M = Zr, Hf). The cations are build of five membered rings which are connected via single Te atoms to a polymer ‐Te‐Te5‐Te‐Te5‐. Out of the six Te atoms of the asymmetric unit of the chain four atoms exhibit two bonds and two atoms exhibit three bonds. The connecting, threefold coordinated Te atoms of the five membered rings carry formally the positive charges. In consistence with the assumption of the presence of throughout localized bonds eH band structure calculations for Te6[ZrCl6] show semiconducting behaviour with a band gap of 1.8 eV.
Formation, Structural Characterization, and Calculated NMR Chemical Shifts of Selenium‐Nitrogen Compounds from SeCl4 and ArNHLi (Ar = supermesityl, mesityl)
Authors: Maaninen Tiina , Tuononen Heikki M. , Kosunen Katja , Oilunkaniemi Raija , Hiitola Johanna , Laitinen Risto , Chivers Tristram 
Published: October 2004

AbstractSupermesityl selenium diimide [Se{N(C6H2tBu3‐2, 4, 6)}2; Se{N(mes*)}2] can be prepared in a good yield from the reaction of SeCl4 and (mes*)NHLi. The molecule adopts an unprecedented anti, anti‐conformation, as deduced by DFT calculations at PBE0/TZVP level of theory and supported by 77Se NMR spectroscopy and a crystal structure determination. An analogous reaction involving (C6H2Me3‐2, 4, 6)NHLi [(mes)NHLi] unexpectedly lead to the reduction of selenium and afforded the selenium diamide Se{NH(mes)}2 that was characterized by X‐ray crystallography and 77Se NMR spectroscopy. The Se‐N bonds of 1.847(3) and 1.852(3) Å show normal single bond lengths. The <NSeN bond angle of 109.9(1)° also indicates a tetrahedral AX2E2 bonding arrangement around selenium. Two N‐H···N hydrogen bonds link the Se{NH(mes)}2 molecule with two discrete (mes)NH2 molecules. In the solid state selenium diamide adopts the anti‐conformation, whereas in solution the presence of both syn‐ and anti‐isomers could be observed. PBE0/TZVP calculations of the shielding tensors of 28 different types of selenium‐containing molecules, for which the 77Se chemical shifts are unambiguously known, were carried out to assist the spectral assignment of Se{N(mes*)}2 and Se{NH(mes)}2.
Preparation of Nanosized Perovskite‐type Oxides via Polyol Method
Authors: Siemons M. , Weirich Th. , Mayer J. , Simon Ulrich 
Published: October 2004

AbstractSeveral perovskite‐type nanosized oxides were prepared via polyol‐mediated synthesis. The crystallinity of the materials was analysed by X‐ray diffraction (XRD). While the “as synthesized” materials are amorphous or show very poor crystallinity, highly ordered materials could be obtained by annealing at 700 °C. Morphology of the materials was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Particle size of the materials lay between 20 and 200 nm.
The Reactions of Hexafluorocyclotriphosphazene with Sodium Phenoxide
Authors: Freund Amy S. , Calichman Michael , Allen Christopher W. 
Published: October 2004

AbstractThe reaction of N3P3F6 (2) with NaOPh led to the phenoxyfluorocyclotriphosphazenes N3P3(OPh)nF6‐n (n = 1(3), 2(4), 3(5)). Structures were assigned using 31P decoupled 19F NMR spectroscopy. The reaction followed a non‐geminal pathway with a 50.7:49.3 cis:trans ratio for 4 and a 28.6:71.4 cis:trans ratio for 5. Comparisons to the analogous reaction of N3P3Cl6 (1) were facilitated by DFT calculations on N3P3(OPh)X5 (X = F, Cl) which show that the NBO charges on the phenyl group are invariant with respect to the identity of the phosphazene. These observations have been correlated to mechanistic models for cyclophosphazene substitution reactions.
Synthetic and Structural Studies on the Cyclic Bis(amino)stannylenes Sn[(NR)2C10H6‐1, 8] and their Reactions with SnCl2 or Si[(NCH2But)2C6H4‐1, 2] (R = SiMe3 or CH2But)
Authors: Avent Anthony G. , Drost Christian , Gehrhus Barbara , Hitchcock Peter B. , Lappert Michael F. 
Published: October 2004

AbstractTreatment of {HNR}2C10H6‐1, 8 [R = SiMe3 (1), CH2But (2)] with Sn[N(SiMe3)2]2 afforded the cyclic stannylene Sn[{NR}2C10H6‐1, 8] [R = SiMe3 (3), CH2But (4)]. From 3 and SnCl2 in THF and crystallisation from toluene, the product was the crystalline tetracyclic compound $Sn(Cl)[\{\overline{N(SiMe_{3})\}_{2}C_{10}H_{6}-1, 8]Sn}Cl$ (5) as the (toluene)0.5‐solvate. Reaction of 4 with the silylene Si[(NCH2But)2C6H4‐1, 2] (6) [abbreviated as Si(NN)] in benzene and crystallisation in presence of Et2O furnished the crystalline tricyclic complex Sn[{Si(NCH2But)2C6H4‐1′, 2′}2‐{(NCH2But)2C10H6‐1, 8}] (7) as the Et2O‐solvate. Complex 5 slowly dissociated into its factors 3 and SnCl2 in toluene, but rapidly in THF. Solutions of 7 in C6D6, C7D8 or THF‐d8, studied by multinuclear, variable temperature NMR spectroscopy, revealed the presence of an equilibrium between 8 (an isomer of 7, in which the skeletal atoms of the eight‐membered ring were $\overline{SnNCCCNSiSi}$, rather than the $\overline{SnSiNCCCNSi}$ of 7) and 4 + 2 Si(NN), with 8 dominant in PhMe but not in THF; additionally 8 was shown to be fluxional and solutions of 8 in C6D6 or C7D8 decomposed to give the silane Si(NN)[(NCH2But)2C10H6‐1, 8], 6 and Sn metal. The X‐ray structures of 3, 5 and 7 are presented.
Do psychological factors increase the risk for back pain in the general population in both a cross‐sectional and prospective analysis?
Authors: Linton Steven James 
Published: October 2004

AbstractThis study aimed to conduct a comprehensive evaluation of background, individual and workplace psychological risk factors to investigated their relationship with spinal pain. Because there is some doubt as to whether the results of cross‐sectional findings hold in longitudinal studies, a prospective study was superimposed upon a cross‐sectional design of the effects of psychological variables on back pain and function to determine, whether similar results are obtained. Participants were workers randomly selected from the general population, where 372 had not experienced pain during the past year, and 209 had experienced considerable pain problems. A cross‐sectional comparison of these groups using multivariate statistics indicated that the most potent risk factors were psychological distress (odds ratio = 13.2) and poor function (odds ratio = 6.4). Much smaller levels of risk were found for perceived workload, gender and foreign birth. Those participants with no pain were followed for one year to determine development of a spinal pain problem. Although few participants developed a significant pain problem, the prospective analyses showed that psychological distress (odds ratio = 2.2), catastrophizing (odds ratio = 3.0), and workload (odds ratio = 2.3) produced the highest odds ratios. Taken together these results underscore the need for a multidimensional view of the development of pain disability. Moreover, individual psychological factors such as distress and catastrophizing as well as work place factors like work load were found to be highly related to the development of back pain in a sample of workers from the general population. The cross‐sectional and prospective results were similar in character and demonstrate that cross‐sectional studies may provide valuable information. Because psychological variables were relevant very early on, these factors may be important targets for pain prevention programs.
Swimming endurance of haddock (Melanogrammus aeglefinus L.) at prolonged and sustained swimming speeds, and its role in their capture by towed fishing gears
Authors: Breen Mike , Dyson Jamie , O'Neill Finbarr G. , Jones Emma , Haigh Michael 
Published: October 2004

AbstractThis paper describes an experiment to determine the swimming endurance of haddock (Melanogrammus aeglefinus) at prolonged swimming speeds. Fish were stimulated to swim in a circular path around an annular tank, using a moving light pattern to trigger the optomotor response. Individually tagged haddock (length range 16.0–40.2 cm) swam in groups over a range of speeds (0.3–0.9 m s−1) and at a constant temperature (9.85 ± 0.07°C). Endurance of individual fish was shown to be related to their swimming speed and length. However, there was also significant variation (p < 0.05) in the performance of fish of approximately equal length. Distinct behaviours and swimming gaits were also identified and associated with the performance of individual fish. The inverse-linear model is introduced, as an alternative to the log-linear model, for describing the relationship between swimming speed and endurance, and estimating maximum sustainable swimming speed (Ums). Estimates of Ums ranged from 0.38 ± 0.03 m s−1 and 3.16 ± 0.02 BL s−1 (for a 16.0-cm fish) to 0.62 ± 0.04 m s−1 and 1.51 ± 0.07 BL s−1 (for a 42.0-cm fish). Ums represents an important threshold in the behavioural physiology of fish, marking the upper limit of aerobic swimming. The relevance of these results and Ums to the fish capture process is discussed.