bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and Characterization of a Two‐Dimensional Zinc Phosphite, Zn3(tren)(HPO3)3·xH2O (x ≈ 0.5; tren = tris(2‐aminoethyl)amine)
Authors: Zhong You‐Ju , Chen Yong‐Mei , Sun Yan‐Qiong , Yang Guo‐Yu
Published: July 2005

A new zinc phosphite with the formula Zn3(tren)(HPO3)3·xH2O (x≈0.5) has been synthesized under hydrothermal conditions and characterized by FTIR, elemental analysis, powder X‐ray diffraction, single‐crystal X‐ray diffraction, thermogravimetric analysis and its fluorescent spectrum. The compound crystallizes in the triclinic system, space group ${\rm P}{\bar 1}$ (No.2), a = 10.1188(9) Å, b = 10.4194(9) Å, c = 10.5176(9) Å, α = 60.763(2)°, β = 70.6150(10)°, γ = 80.725(2)°, V = 912.77(14) Å3, Z = 2. The structure consists of double crankshaft chains, which are linked by Zn‐O‐P bonds to form 8‐ and 12‐membered channels along the [100] direction. The claw‐like Zn‐centered complexes of Zn(N4C6H18) as the supported templates, hang into the 12‐MR channels through Zn‐O‐P linkages with framework.
Structural Aspect of CuCN Catalytic Cyclodimerization of N‐Allylquinolinium Halides
Authors: Pavlyuk Oleksii , Lis Tadeusz , Mys'kiv Marian G.
Published: July 2005

By a reaction between the corresponding [N‐allylquinolinium]X (X = Cl, Br, I) and CuCN in a methanolic medium crystals of [C24H21N2][CuCl1.35Br0.65] (1), [C24H21N2][CuBr2] (2) and [C24H21N2]I (3) have been obtained and characterized structurally by X‐ray (at 100 K). Isostructural complexes 1 and 2 crystallize in monoclinic space group P21/n, Z = 4: 1 a = 13.193(4), b = 19.185(5), c = 8.429(3), β = 104.85(3)°, V = 2062(1) Å3, R = 0.051 for 3359 reflections; 2 a = 13.373(4), b = 19.104(6), c = 8.544(3) Å, β = 104.58(3)°, V = 2112(1) Å3, R = 0.057 for 3297 reflections. Compound 3 crystallizes in monoclinic system, space group P21/n, Z = 4, a = 8.889(2), b = 16.842(3), c = 13.294(3) Å, β = 104.71(3)° V = 1925(1) Å3, R = 0.034 for 4042 reflections. The same cation [C24H21N2]+ in the compound 1–3 appeared as a product of N‐allylquinolinium catalytic cyclodimerization. Neither N‐allyl nor C‐vinyl groups participate in CuI π‐coordination in the structures of 1 and 2, therefore [CuX2]− anions can possess a linear form.
Recent Advances in the Chemistry of “Clusters” and Coordination Polymers of Alkali, Alkaline Earth Metal and Group 11 Compounds
Authors: Fromm Katharina M. , Gueneau Estelle D. , Robin Adeline Y. , Maudez William , Sague Jorge , Bergougnant Rémi
Published: July 2005

This contribution gives an overview on the different subjects treated in our group. One of our fundamental interests lies in the synthesis and study of low‐dimensional polymer and molecular solid state structures. We have chosen several synthetic approaches in order to obtain such compounds.

Firstly, the concept of cutting out structural fragments from a solid state structure of a binary compound will be explained on behalf of BaI2. Oxygen donor ligands, used as chemical scissors on BaI2, allow obtaining three‐, two‐, one‐ and zero‐dimensional derived compounds depending on their size and concentration. Thus, a structural genealogy tree for BaI2 can be established. This method, transferred to alkali halides using crown ethers and calix[n]arenes as delimiting ligands, leads us to the subject of one‐dimensional ionic channels.

A second chapter deals with the supramolecular approach for the synthesis of different dimensional polymer structures derived from alkaline earth metal iodides, and based on the combination of metal ion coordination with hydrogen bonding between the cationic complexes and their anions. Under certain circumstances, rules can be established for the prediction of the dimensionality of a given compound, thus contributing to the fundamental problem of structure prediction in crystal engineering.

A third part describes a fundamentally new synthetic pathway for generating pure alkaline earth metal cage compounds as well as alkali and alkaline earth mixed metal clusters. In a first step, different molecular precursors, such as solvated alkaline earth metal halides are investigated as a function of the ligand size and reactivity. They are then reacted with some alkali metal compound in order to partially eliminate alkali halide and to form the clusters. The so obtained unique structures of ligand stabilized metal halide, hydroxide and/or alkoxide and aryloxide aggregates are of interest as potential precursors for oxide materials. Approaches to two synthetic methods of the latter, sol‐gel and (MO)‐CVD, are investigated with our compounds.

In order to generate single source precursors for oxide materials, we started to investigate transition metal ions, especially Cu and Ag, using multitopic ligands. This has led us into the fundamental problematic of “crystal engineering” and solid state structure prediction and we found ourselves confronted to numerous interesting cases of polymorphism and pseudo‐polymorphism. Weak interactions, such as π‐stacking, H‐bonding and metal‐metal interactions, and solvent, counter ion and concentration effects seem to play important roles in the construction of such low‐dimensional structures.

Finally, the physical properties of some of our compounds are described qualitatively in order to show the wide spectrum of possibilities and potential applications for the chemistry in this field.
$^{1}_{\infty}\rm [Li_{3}(NbSe_{4})\cdot4MeCN]$ – ein neues lösliches Tetrachalkogenoniobat
Authors: Feuerhake Robert , Sahin Hülya , Fenske Dieter
Published: July 2005

$^{1}_{\infty}\rm [Li_{3}(NbSe_{4})\cdot4MeCN]$ – a Novel Soluble Tetrachalcogenoniobate

In Acetonitrile, Nb(OEt)5 reacts with LiOMe and Se(SiMe3)2 to form the novel tetraselenoniobate $^{1}_{\infty}\rm [Li_{3}(NbSe_{4})\cdot4MeCN]$. The molecular structure was determined by single crystal X‐ray diffraction. The new compound is soluble in polar organic solvents and seems to be a suitable starting material for the synthesis of new heterobimetallic complexes, as some reactivity towards copper phosphine complexes could be observed.
(Sr2N)H: Untersuchungen zur Redox‐Intercalation von Wasserstoff in Sr2N
Authors: Chemnitzer René , Auffermann Gudrun , Többens Daniel M. , Kniep Rüdiger
Published: July 2005

(Sr2N)H: On the Redox‐Intercalation of Hydrogen into Sr2N

Strontium‐nitride‐hydride is obtained as brown‐yellow single phase powder by reaction of strontium‐subnitride (Sr2N) with hydrogen (200 bar, 620 K) and subsequent treatment under vacuum (10−6 bar, 870 K). The structure determination was carried out by a combination of X‐ray and neutron diffraction experiments on a deuterated sample. The elemental composition of the ternary compound was confirmed by means of chemical analyses. (Sr2N)D crystallizes in the space group $R{\bar 3}m$ with a = 381.91(2) pm and c = 1887.61(2) pm. Strontium (Sr2+) in the crystal structure of (Sr2N)D is arranged with an only slightly distorted ccp‐motif. Nitrogen (N3−) and deuterium (D−) occupy the octahedral voids of the Sr2+‐matrix in an ordered manner resulting in an alternating sequence of layers (anti‐α‐NaFeO2‐type structure).
Metathetical Reactions in the System Na(K)PF6 – LiBF4 – Aprotic Media
Authors: Plakhotnyk Andriy V. , Tarasova Lidiya D. , Ernst Ludger , Schmutzler Reinhard
Published: July 2005

19F NMR spectroscopy, X‐ray powder diffraction, elemental analysis, and ab initio quantum chemical calculations were used to study metathetical reactions between potassium or sodium hexafluorophosphate and lithium tetrafluoroborate in a mixture of propylene carbonate (PC) – dimethyl carbonate (DMC). It was shown that the increase in size of the cations in the second coordination sphere from Na+ to K+ results in an increase of the equilibrium conversion. This is in agreement with the influence of the cation size on the solubility of tetrafluoroborates in the media investigated.
Versuche zur Darstellung von t‐BuCN5S3 und die unerwartete Isolierung einer kovalenten Modifikation von Tetraschwefelpentastickstoff‐chlorid S4N5Cl
Authors: Knapp Carsten , Lork Enno , Borrmann Tobias , Stohrer Wolf‐Dieter , Mews Rüdiger
Published: July 2005

Attempts to prepare t‐BuCN5S3 and the unexpected Isolation of a covalent Modification of Tetrasulfur‐pentanitrogen Chloride S4N5Cl

Attempts to prepare the bicyclic sulfur‐nitrogen heterocycle t‐BuCN5S3 via (NSCl)3 and the corresponding silylated amidinates and amidines failed because of the inaccessibility of the silylated intermediates. Reactions of MN(SiMe3)2 (M = Li, Na) with t‐BuCN did not yield the expected amidinates t‐BuC(NSiMe3)2M, instead the adducts [t‐BuCN·MN(SiMe3)2]2 were isolated. The attempted synthesis of t‐BuCN5S3 from t‐BuCN(SiMe3)2M, prepared in situ from t‐BuLi and Me3SiNCNSiMe3, and (NSCl)3 unexpectedly resulted a mixture of S4N5Cl and S5N6. The crystal structure determination for S4N5Cl showed a new covalent modification of S4N5Cl (monoclinic, P21/c, a = 1005.0(4) pm, b = 1193.5(8) pm, c = 1152.5(6) pm, β = 93.67(3)°), different from the known ionic S4N5Cl (orthorhombic, Pnma, a = 1738.90(10) pm, b = 781.50(10) pm, c = 483.03(5)). The unsuccessful attempts to prepare t‐BuCN5S3, the unexpected formation of S4N5Cl and S5N6, and the bonding properties of the new covalent modification of S4N5Cl are discussed.
Spectroscopic and Electrochemical Behavior of the Methyl and Ethyl Derivatives of Bis(acetylacetonato) oxovanadium(IV)
Authors: dos Santos Claro Paula C. , González‐Baró Ana C. , Parajón‐Costa Beatriz S. , Baran Enrique J.
Published: July 2005

The infrared, Raman and electronic spectra of the oxovanadium (IV) complexes of the 3‐methyl and 3‐ethyl substituted acetylacetone were recorded and discussed in detail, in comparison with that of the bis(acetylacetonato) complex and on the basis of the known structural data of these compounds. The electrochemical behavior of the three complexes was investigated by cyclic voltammetry in DMSO solutions, and the mechanism of the involved processes is briefly discussed.
The Structure of the Tricosahydrotetracosaborate Anion B24H233−
Authors: Volkov Oleg , Hu Chunhua , Kölle Ulrich , Paetzold Peter
Published: July 2005

Following a modified prescription of 1969, the anion B24H233− was formed from B12H122− by electrolysis at 1.5 V. The crystal structure of M3(B24H23)(MeCN)1.5 (M = [CpFe{C5H4(CH2NMe3)}]) revealed the anion to consist of two icosahedral B12H11 units, connected by a bent B–H–B bridge. From the reaction of B12H122− with CF3COOH, reported in the literature as a source of B24H233−, the substitution product B12H11(CF3COO)2− was isolated.
The Crystal Structures of R3CuSnS7 (R = La–Nd, Sm, Gd–Ho)
Authors: Gulay L. D. , Olekseyuk I. D. , Wołcyrz Marek , Stępień‐Damm J.
Published: July 2005

Crystal structures of R3CuSnS7 (R = La–Nd, Sm, Gd–Ho) (La3CuSiS7 structure type, space group P63, Pearson symbol hP24) were determined by means of X‐ray single crystal diffraction (a = 1.0317(1) nm, c = 0.60274(7) nm, R1 = 0.0202 for La3CuSnS7; a = 1.0209(1) nm, c = 0.60150(7) nm, R1 = 0.0273 for Ce3CuSnS7; a = 1.0075(1) nm, c = 0.60212(6) nm, R1 = 0.0224 for Nd3CuSnS7) and X‐ray powder diffraction (a = 1.01417(2) nm, c = 0.60210(2) nm, RBragg = 0.0824 for Pr3CuSnS7; a = 0.99288(2) nm, c = 0.60800(2) nm, RBragg = 0.0926 for Sm3CuSnS7; a = 0.98087(3) nm, c = 0.61511(3) nm, RBragg = 0.0885 for Gd3CuSnS7; a = 0.97512(2) nm, c = 0.61573(2) nm, RBragg = 0.0904 for Tb3CuSnS7; a = 0.97024(2) nm, c = 0.61694(2) nm, RBragg = 0.0918 for Dy3CuSnS7; a = 0.96527(2) nm, c = 0.61731(2) nm, RBragg = 0.0864 for Ho3CuSnS7). The structures are built up from columns of distorted face‐sharing sulfur anticuboctahedra arranged along the c‐axis. The columns are connected with each other via common edges. The remaining atoms are located in the intercolumnar channels.
π–π Stacking‐Interlinked Molecular Squares with Hepta‐Coordinated Cadmium(II) Corners, [Cd(DMAP)3(NO2)2]·0.5H2O
Authors: Marandi Farzin , Soudi Ali Akbar , Morsali Ali , Kempe Rhett
Published: July 2005

The single crystal X‐ray analysis data of the new hepta‐coordinate cadmium(II) complex of N,N‐dimethyl‐N‐(4‐pyridyl)amine (DMPA), [Cd(DMPA)3(NO2)2]·0.5H2O, shows that the coordination environment around the CdII is pentagonal bipyramidal. Furthermore, self‐assembly of this complex as molecular squares that interlink via π–π stacking interactions is observed. This network contains voids that are filled by water molecules.
Synthesis, Characterization and X‐ray Crystal Structure of a Chromium(III) Complex Obtained from a Proton‐Transfer Compound Containing 1,10‐Phenanthroline‐2,9‐dicarboxylic Acid and 2,6‐Pyridinediamine
Authors: Moghimi Abolghasem , Alizadeh Robabeh , Aragoni M. Carla , Lippolis Vito , Aghabozorg Hossein , Norouzi Parviz , Isaia Francesco , Sheshmani Shabnam
Published: July 2005

The novel 1,10‐phenanthroline‐2,9‐dicarboxylate containing Chromium(III) complex, (pydaH)[Cr(phendc)2] · 5H2O, was synthesized using proton‐transfer compound LH2, (pydaH2)2+(phendc)2−, (pyda: 2,6‐pyridinediamine; phendcH2: 1,10‐phenanthroline‐2,9‐dicarboxylic acid) and thoroughly characterized by elemental analysis, IR spectroscopy, X‐ray crystallography and cyclic voltammetry. The complex crystallizes in the monoclinic space group P21/n with four formula units in the unit cell. The unit cell dimensions are: a = 13.962(3) Å, b = 14.529(3) Å, c = 16.381(3) Å and β = 106.691(4)°. In this complex, 1,10‐phenanthroline‐2,9‐dicarboxylate acts as a tridentate ligand and the lattice is composed of anionic hexacoordinated complex, [Cr(phendc)2]−, 2,6‐pyridiniumdiamine counter ion, (pydaH)+, and five lattice water molecules.

Crystallographic characterization revealed that the resulting supramolecular structure is strongly stabilized by complicated network of hydrogen bonds between the crystallization water molecules, counter ion and both coordinated and uncoordinated carboxylate groups. There is no relevant π‐π interaction for this anionic complex between pyda or phendc moieties. The electrochemical studies indicated over potential for both the cathodic and anodic peaks of the complex with respect to the free Cr3+ ion, as a consequence of the energy requirement for rearrangement of the ligand at electrode surface.
Synthesis and Structure of Bis(para‐methoxyphenyl)selenoxide and its Monohydrate. Theoretical Considerations of the Hydration of Diorganoselenium Oxides
Authors: Beckmann Jens , Duthie Andrew
Published: July 2005

The title compound was prepared by base hydrolysis of (p‐MeOC6H4)2SeCl2 in water and isolated as the crystalline monohydrate, (p‐MeOC6H4)2SeO·H2O, in which the water molecule is associated via hydrogen‐bonding. Water‐free (p‐MeOC6H4)2SeO was obtained crystalline after drying and recrystallisation from toluene. Both crystal phases were investigated by single crystal X‐ray diffraction. Preliminary DFT calculations at the B3LYP/LANL2DZdp level of theory suggest that the hydrogen bonded complexes R2SeO·H2O (R = H, Me, Ph) are by 2.79, 3.36 and 11.10 kcal mol−1 more stable than the corresponding elusive diorganoselenium dihydroxides R2Se(OH)2. The hydrogen bond energies of R2SeO·H2O (R = H, Me, Ph) are 5.98, 7.18 and 5.89 kcal mol−1.
Synthesis of Lanthanide Bromide Complexes from Oxides. The Crystal Structures of [LnBr2(diglyme)2][LnBr4(diglyme)] (Ln = Sm, Eu) and [LnBr2(HMPA)4]Br·0.5H2O (Ln = La, Sm)
Authors: Petriček Saša
Published: July 2005

The reaction of the lanthanide oxides, bromotrimethylsilane and water in THF resulted in [LnBr3(THF)x]. If digylme (diglyme = diethylen glicol dimethyl ether) was added to these reaction mixtures in the mole ratio n(Ln): n(diglyme) ∼ 1: 2.2 – 3, the ionic complexes [LnBr2(diglyme)2][LnBr4(diglyme)] (Ln = La (1), Sm (2), Eu (3)) were isolated. Crystal structures of the two new complexes, 2 and 3, which were recrystallized from dichloromethane, were determined. The immediate reaction of the complexes 1 and 2 with HMPA (HMPA = hexamethylphosphoramide) in toluene resulted in [LnBr2(HMPA)4]Br·0.5H2O (Ln = La(4), Sm (5)).
Synthese, Schwingungsspektren und Kristallstrukturen der Nitratoargentate (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN und (Ph4P)[Ag2(NO3)3]
Authors: Neumüller Bernhard , Weller Frank , Schmock Fritjof , Dehnicke Kurt
Published: July 2005

Synthesis, Vibrational Spectra, and Crystal Structures of the Nitrato Argentates (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN and (Ph4P)[Ag2(NO3)3]

Tetraphenylphosphonium bromide reacts in acetonitril suspension with excess silver nitrate to give (Ph4P)[Ag(NO3)2(CH3CN)]·CH3CN (1), whereas (Ph4P)[Ag2(NO3)3] (2) is obtained in a long‐time reaction from (Ph4P)Br and excess AgNO3 in dichloromethane suspension. Both complexes were characterized by vibrational spectroscopy (IR, Raman) and by single crystal structure determinations.

1: Space group P21/c, Z = 4, lattice dimensions at 193 K: a = 1781.5(3), b = 724.8(1), c = 2224.2(3) pm, β = 96.83(1)°, R1 = 0.0348. 1 contains isolated complex units [Ag(NO3)2(CH3CN)]−, in which the silver atom is coordinated by the chelating nitrate groups and by the nitrogen atom of the solvated CH3CN molecule with a short Ag—N distance of 220.7(4) pm.

2: Space group I2, Z = 4, lattice dimensions at 193 K: a = 1753.4(4), b = 701.7(1), c = 2105.5(4) pm, R1 = 0.072. In the polymeric anions [Ag2(NO3)3]− each silver atom is coordinated in a chelating manner by one nitrate group and by two oxygen atoms of two bridging nitrate ions. In addition, each silver atom forms a weak π‐bonding contact with a phenyl group of the (Ph4P)+ ions with shortest Ag···C separations of 266 and 299 pm, respectively, indicating a (4+1) coordination of silver atoms.
The Coordination Chemistry of the Ylide Adduct O2CC(PPh3)2; Preparation, Crystal Structures, and Spectroscopic Properties of [Cl3In{O2CC(PPh3)2}], [Cl2Sn{O2CC(PPh3)2}], and [I2In{O2CC(PPh3)2}2]I
Authors: Petz Wolfgang , Köhler Karen , Mörschel Philipp , Neumüller Bernhard
Published: July 2005

The betain like carbodiphosphorane CO2 adduct O2CC(PPh3)2 (1a) can serve as a ligand versus hard Lewis acids from main group compounds. Thus, reaction of 1a with InCl3, InI3 and SnCl2 in polar solvents leads to the addition compounds [Cl3In{O2CC(PPh3)2}] (2), [Cl2SnO2CC(PPh3)2}] (3) and the salt like compound [I2In{O2CC(PPh3)2}2]I (4) in good yields. Whereas in the indium compounds 1a acts as a chelating ligand, in the tin compound the molecule coordinates with one oxygen atom only as a monodentate ligand. 4 has a pyramidal structure with a stereochemical active pair of electrons. All compounds could be characterized by X‐ray analyses and the usual spectroscopic methods.
Synthesis and Crystal Structure Determination by X‐Ray Powder Diffraction of Nickel Tetrametaphosphimate Octahydrate Ni2(PO2NH)4 · 8 H2O
Authors: Römer S. Rebecca , Schnick Wolfgang
Published: July 2005

Ni2(PO2NH)4 · 8 H2O is isotypic with M2(PO2NH)4 · 8 H2O (M = Mg, Mn, Co, Zn) and crystallizes in the space group P21/c, Z = 2, with a = 641.25(1), b = 1041.42(1), c = 1278.18(2) pm and β = 104.243(1)°. The structure is composed of Ni2+ and (PO2NH)44− ions as well as crystal water molecules. The P4N4 rings of the (PO2NH)44− ions exhibit a slightly distorted chair–2 conformation, which has been described by torsion angles, displacement asymmetry parameters and puckering parameters. The tetrametaphosphimate anions are connected forming layers. These layers are linked solely by hydrogen bonds, forming a three‐dimensional network.
Synthese und Kristallstruktur von 2‐Azido‐4,6‐dichloro‐s‐triazin
Authors: Gibson Katharina , Tragl Sonja , Meyer H.‐Jürgen
Published: July 2005

Synthesis and Crystal Structure of 2‐Azido‐4,6‐dichloro‐s‐triazine

Single crystals of 2‐azido‐4,6‐dichloro‐s‐triazine were obtained from a reaction between cyanuric chloride and sodium azide. The structure of this compound was determined by single crystal X‐ray diffraction. 2‐Azido‐4,6‐dichloro‐s‐triazine crystallizes in the orthorhombic space group Pbca (no. 61), Z = 8, a = 746.48(8) pm, b = 952.6(1) pm, c = 2001.6(2) pm. The crystal structure contains (C3N3)(N3)Cl2 molecules being arranged in a tape‐like fashion, with tapes running along a‐axis direction. The tapes are combined with each other by interlocking azide‐ligands including an angle of approximately 90°. This arrangement leads to the formation of corrugated layers in the crystal structure.
Silver(I) Saccharinato Complexes with Ethylenediamine and N,N‐Dimethylethylenediamine – [Ag2(sac)2(en)(H2O)]n and [Ag2(sac)2(dmen)2]
Authors: Yilmaz Veysel T. , Hamamci Sevim , Kazak Canan
Published: July 2005

Two new silver(I)‐saccharinato (sac) complexes with ethylenediamine (en) and N,N‐dimethylethylenediamine (dmen) were synthesized and characterized by elemental analysis, FT–IR spectroscopy, thermal analysis and single crystal X‐ray diffraction. The [Ag2(sac)2(en)(H2O)]n complex, 1, is a coordination polymer in which[Ag(sac)2(H2O)]− and [Ag(en)2]+ ions are bridged by one of the sac ligands and Ag–Ag bonds [2.9920(3) Å], resulting in [Ag2(sac)2(en)(H2O)] building blocks which are also linked into one‐dimensional helical chains by bridging en ligands. Each silver(I) atom is three‐coordinate with a distorted T–shaped coordination of AgN2O. The individual chains of 1 are further stacked by π–π; interactions, OW–H···O and N–H···O hydrogen bonds to form a three–dimensional supramolecular framework. The [Ag2(sac)2(en)2] complex, 2, has two molecules in its asymmetric unit, and each dimer is formed by bridging of two monomeric [Ag(sac)(dmen)] units by Ag–Ag bonds. The silver(I) atoms exhibit a distorted T–shaped coordination of AgN3 with an N–bonded sac and bidentate dmen ligands. The Ag···Ag separations in the pair of dimers are 3.2725(9) and 3.3127(9) Å. The dimeric molecules of 2 are connected to one‐dimensional hydrogen bonded chains by N–H···O hydrogen bonds.
Mononuclear Imido Amido Complexes via Exhaustive Ammonolysis of Niobium and Tantalum Pentachloride with tert‐Butyl Amine
Authors: Merkoulov Alexei , Schmidt Simone , Harms Klaus , Sundermeyer Jörg
Published: July 2005

Reaction of MCl5 (M = Nb, Ta) with excess of tBuNH2 in the presence of pyridine leads to formation of mononuclear complexes [M(NtBu)(NHtBu)Cl2Py2],M = Nb (1), Ta (2). These new key compounds are characterized by 1H, 13C NMR spectroscopy, mass spectrometry and elemental analyses. A single crystal structure analysis of [Ta(NtBu)(NHtBu)Cl2Py2] (2) reveals, that surprisingly chloro and not pyridine ligands are trans to the strongest π donor ligands [NtBu]2− and [NHtBu]−.
Einkristalle von La[AsO4] im Monazit‐ und Sm[AsO4] im Xenotim‐Typ
Authors: Kang Dong‐Hee , Schleid Thomas
Published: July 2005

Single Crystals of La[AsO4] with Monazite‐ and Sm[AsO4] with Xenotime‐Type Structure

Brick‐shaped, transparent single crystals of colourless monazite‐type La[AsO4] (monoclinic, P21/n, a = 676.15(4), b = 721.03(4), c = 700.56(4) pm, β =104.507(4)°, Z = 4) and pale yellow xenotime‐type Sm[AsO4] (tetragonal, I41/amd, a = 718.57(4), c = 639.06(4) pm, Z = 4) emerge as by‐products from alkali and rare‐earth metal chloride fluxes whenever the synthesis of lanthanide(III) oxoarsenate(III) derivatives from admixtures of the corresponding sesquioxides in sealed, evacuated silica ampoules is accompanied by air intrusion and subsequent oxidation. Nine oxygen atoms from seven discrete [AsO4]3− tetrahedra recruit the rather irregular coordination sphere of La3+ (d(La3+−O2−) = 248 – 266 pm plus 291 pm) and even a tenth ligand could be considered at a distance of 332 pm. The trigonal dodecahedral figure of coordination consisting of eight oxygen atoms at distances of 236 and 248 pm (4× each) about Sm3+ is provided by only six isolated tetrahedral [AsO4]3− units. Alternating trans‐edge condensation of the latter with the [LaO9+1] polyhedra of monazite‐type La[AsO4] and the [SmO8] polyhedra of xenotime‐type Sm[AsO4] constitutes the main structural chain features along [100] or [001], respectively. The bond distances and angles of the complex [AsO4]3− anions range within common intervals (d(As5+−O2−) = 167 – 169 pm, ∢(O–As–O) = 100 – 116°) for both lanthanide(III) oxoarsenates(V) presented here.
Jahn‐Teller‐Ordnung in Mangan(III)‐fluoridsulfaten. II. Phasenübergang und Verzwillingung bei K2[MnF3(SO4)] und 1D Magnetismus in Verbindungen A2[MnF3(SO4)] (A = K, NH4, Rb, Cs)
Authors: Klein Ute , Hahn Friedemann , Massa Werner , Pebler Jürgen
Published: July 2005

Jahn‐Teller Ordering in Manganese(III) Fluoride Sulfates. II. Phase Transition and Twinning of K2[MnF3(SO4)] and 1D Magnetism in Compounds A2[MnF3(SO4)] (A = K, NH4, Rb, Cs)

According to single‐crystal X‐ray investigations, K2[MnF3(SO4)] crystallizes at low temperature, like the isostructural Rb, NH4, and Cs analogues in space group P21/c, Z = 4, e.g. at 100 K with a = 7.197, b = 10.704, c = 8.427Å, β = 91.84°. Below about 300 K, the crystals are found to be [001] axis twins. Using a new integration method for area detector records, nearly complete intensity data could be gained allowing for structure refinements of similar quality as for untwinned crystals (e.g. at 100 K: wR2 = 0.050, R = 0.020 for all reflections). With rising temperature, the monoclinic angle approaches continuously 90°. For an ordering parameter Δβ = β−90° a 2nd‐order phase transition is observed with an exponent λ = 0.17. At the transition temperature of 280 K resulting from the fit, the monoclinic structure changes – with delay – to orthorhombic with the minimum super‐group Pnca, a = 7.243, b = 10.763, c = 8.457Å, R = 0.024, as found in an early structure determination at room temperature by Edwards 1971. In the chain‐like [MnF3(SO4)]2− anions, manganese(III) is octahedrally coordinated by two trans‐terminal and two trans‐bridging fluorine ligands as well as by the O atoms of two trans‐bridging sulfate ligands. At low temperature, the octahedral elongation by the Jahn‐Teller effect alternates between a F–Mn–F and an O–Mn–O axis (antiferrodistortive ordering). All bridges are asymmetric. From about 320 K on they become symmetric. Due to 2D dynamical Jahn‐Teller effect all octahedra appear compressed. All compounds A2[MnF3(SO4)] show 1D antiferromagnetism. The antiferrodistortive Jahn‐Teller order at low temperatures and the small bridge angles explain the much lower magnetic exchange energies and their inverse relation to the bridge angles as compared with other fluoromanganate(III) chain compounds with the usual ferrodistortive ordering.
Competitive Coordination of the Uranyl ion by Perchlorate and Water – The Crystal Structures of UO2(ClO4)2·3H2O and UO2(ClO4)2·5H2O and a Redetermination of UO2(ClO4)2·7H2O (Z. Anorg. Allg. Chem. 2003, 629, 1012–1016)
Authors: Fischer A.
Published: July 2005

In the article “Competitive Coordination of the Uranyl ion by Perchlorate and Water – The Crystal Structures of UO2(ClO4)2·3H2O and UO2(ClO4)2·5H2O and a Redetermination of UO2(ClO4)2·7H2O” (Z. Anorg. Allg. Chem. 2003, 629, 1012–1016), some wrong parameters and bond lengths for UO2(ClO4)2·7H2O were given in table 1 and table 3

The correct parameters are: a = 1449.5(2) pm, b = 921.6(1) pm, c = 1067.5(2) pm, V = 1422.5(4)·106 pm3, ρ = 2.712 g·cm−3, μ = 119 cm−1.

The corrected bond lengths for this structure are U–O(1) 175.8(5) pm, U–O(2) 239.1(5) pm, U–O(3) 240.8(5), U–O(4) 242.0(7).

A cif file with the correct data has been deposited with the ICSD.
Educating Genetic Counselors in Australia: Developing an International Perspective
Authors: Sahhar Margaret A. , Young Mary‐Anne , Sheffield Leslie J. , Aitken MaryAnne
Published: July 2005

The demand for genetic counseling services is increasing worldwide. This paper highlights the Australian experience of genetic counselor education and the history of the profession. The relevance of local factors, including the healthcare system, the education system and the small population in the evolution of the 1‐year training programs are considered as an alternative model for emerging programs. The development of the education and training processes compared to that of other countries namely the United States of America (USA), the United Kingdom (UK) and Canada is discussed. The importance of international collaborations between the programs, to facilitate academic discussion and possible curriculum innovations, and to maintain professional understanding between genetic counselors is emphasized. Core genetic counseling competencies have been published for the UK and USA and an Australian set is proposed. In conclusion future directions are considered, including international issues around genetic counseling certification, reciprocity, and the potential for an Australian role in training genetic counselors in South East Asia.
An Assessment of Risk Understanding in Hispanic Genetic Counseling Patients
Authors: Eichmeyer Jennifer N. , Northrup Hope , Assel Michael A. , Goka Thomas J. , Johnston Dennis A. , Williams Aimee Tucker
Published: July 2005

This study sought to identify if differences existed in risk comprehension and risk format understanding between genetic counseling patients of Hispanic and Caucasian ethnicity. A total of 107 questionnaires were collected, 56 from Hispanic patients, and 51 from Caucasian controls. Of the total population 41.1% (44/107) could not demonstrate sufficient risk understanding, which was 71.4% (40/56) of Hispanics and 7.8% (4/51) of Caucasians. Fractions were the best‐understood format for all participants. However, both Hispanics and Caucasians had difficulties with the percentage risk format. Discrepancies were also noted in qualitative word format understanding. Awareness of differences in risk comprehension may affect the selection of counseling techniques and strategies utilized by genetic counselors when educating patients about risk related information.
Psychosocial Issues That Face Patients With Charcot‐Marie‐Tooth Disease: The Role of Genetic Counseling
Authors: Arnold Angela , McEntagart Meriel , Younger David S.
Published: July 2005

Charcot‐Marie‐Tooth (CMT) disease is a hereditary debilitating progressive muscular atrophy and sensory neuropathy of the distal extremities. CMT is usually nonlife threatening. Signs of the disease usually present in childhood or in young adulthood and the level of disability can be variable within and between families. Research addressing specific psychosocial and emotional issues faced by individuals with CMT is limited. Fourteen adults with a clinical and/or molecular diagnosis of CMT (ages 32–74 years) consented to an audio taped interview. The format of the interview was based around an informal questionnaire to prompt and guide the interviewee to describe their experiences of living with a disabling genetic disorder. The interviews focused on their experiences of first symptoms and diagnosis, their life experience with CMT, their limitations due to disability and the role of genetic counseling. This study identifies and explores life issues that individuals with CMT may face, specifically grief over the loss of independence, emotional pain and stress such as embarrassment and guilt of passing on a gene mutation, impact on quality of life, the impact of wearing orthopedic devices, and fear of progressive disability. Our findings suggest that that there are emotional and psychosocial issues specific to affected individuals at different life stages and genetic counselors need to be aware of these issues in order to provide age appropriate support and advice to individuals affected by CMT.
Women's Attitudes Toward Testing for Fragile X Carrier Status: A Qualitative Analysis
Authors: Anido Aimee , Carlson Lisa M , Taft Lisa , Sherman Stephanie L.
Published: July 2005

Fragile X syndrome (FXS) is primarily due to a repeat expansion mutation found in the FMR1 X‐linked gene. We have conducted a qualitative analysis of responses from women concerning their attitudes toward testing for carrier status of the fragile X mutation among reproductive‐age women. We obtained responses from focus groups including women with and without FXS in their families. We found the following themes: (1) mothers of children with FXS have difficulty formulating their opinions on population screening because of their unique experiences surrounding their own carrier diagnosis and their relationship with their children with FXS, (2) the motivation for carrier testing and need for information differ by family history of FXS and parental status, and (3) the timing of carrier testing with respect to a woman's life stage dictates whether carrier information will be viewed as beneficial or detrimental. There was evidence that non‐carrier women from the general population would be wholly unprepared for positive carrier results. These findings have significant implications for genetic counseling as well as for population screening.
Utilization of evidence‐based therapies for heart failure in the institutionalized elderly
Authors: Shibata Marcelo C. , Soneff Cynthia M. , Tsuyuki Ross T.
Published: July 2005

Objectives:

Heart failure (HF) is a major source of morbidity and mortality in elderly populations. A significant proportion of the elderly with HF are living in long‐term care facilities. Little is known about their management. The aim of this study was to evaluate the use of evidence‐based therapies in institutionalized elderly patients with HF.

Design, setting and participants:

Retrospective chart review conducted at 15 long‐term care facilities in the Capital Health Region (Edmonton, Alberta). Residents ≥65 years of age with HF were identified using a pharmacy database.

Results:

Overall prevalence of HF was 15% (313/2062 residents). Mean age was 87 years, median duration of residence was 1.8 years. Utilization of ACE‐inhibitors, beta‐blockers and spironolactone was 51%, 16% and 10%, respectively. Use of these medications was not significantly different between subgroups of those with and without contraindications to the therapies, different advance directive levels, gender or age. Sodium and fluid restricted diets were prescribed in only 11.0% and 3.8% of residents. Weight was not regularly monitored. Influenza and pneumococcal vaccination were administered to 60.4% and 81.2% of the residents.

Conclusion:

The use of evidence‐based therapies in institutionalized elderly patients with HF is low, and unexplained by contraindications or advance directives. Efforts to increase the utilization of evidence‐based therapies and improve monitoring are warranted.
Cardiac repolarization. The long and short of it*
Authors: Antzelevitch Charles
Published: July 2005

Heterogeneity of transmural ventricular repolarization in the heart has been linked to a variety of arrhythmic manifestations. Electrical heterogeneity in ventricular myocardium is due to ionic distinctions among the three principal cell types: Endocardial, M and Epicardial cells. A reduction in net repolarizing current generally leads to a preferential prolongation of the M cell action potential. An increase in net repolarizing current can lead to a preferential abbreviation of the action potential of right ventricular epicardium or left ventricular endocardium. These changes can result in amplification of transmural heterogeneities of repolarization and thus predispose to the development of potentially lethal reentrant arrhythmias. The long QT, short QT, Brugada and catecholaminergic VT syndromes are all examples of pathologies that have very different phenotypes and aetiologies, but share a common final pathway in causing sudden death via amplification transmural or other spatial dispersion of repolarization within the ventricular myocardium. These same mechanisms are likely to be responsible for life-threatening arrhythmias in a variety of other cardiomyopathies ranging from heart failure and hypertrophy, which may involve mechanisms very similar to those operative in long QT syndrome, to isch-aemia and infarction, which may involve mechanisms more closely resembling those responsible for the Brugada syndrome.
Atosiban and nifedipin for the treatment of preterm labor
Authors: Kashanian M. , Akbarian A.R. , Soltanzadeh M.
Published: July 2005

Objective

To perform a comparison between atosiban (oxytocin antagonist) and nifedipin (calcium channel blocker) for acute treatment of preterm labor and their maternal safety. Methods: A randomized controlled trial study was performed on 80 pregnant women with preterm labor, between 26 and 34 weeks of pregnancy, in Akbar Abadi Teaching Hospital in Tehran, Iran. 40 women (the atosiban group) were compared with another 40 women (the nifedipin group) for the drugs' efficacy in delaying delivery for more than 48 h in order to undergo steroid therapy, and for more than 7 days or more, and also to assess their maternal safety. The duration between the drugs' administration and delivery were compared. The statistical analysis was performed using the Statistical Package for Social Science (SPSS). Results: There was no statistically significant difference between the two groups in the treatment of preterm labor. Atosiban was effective in 82.5% of cases, and nifedipin in 75% of the cases (p = 1.000), for delaying delivery for 48 h. Atosiban was effective in 75% of the cases, and nifedipin in 65% of the cases, for delaying delivery for more than 7 days. The maternal side effects in the atosiban group were 17.5%, and in the nifedipin group they were 40%, which had a statistically significant difference (p = 0.027). The duration between treatment and delivery was 29.03 ± 16.12 days in the atosiban group and 22.85 ± 13.9 days in the nifedipin group with no statistically significant difference (p = 0.79). Conclusion: Atosiban is an effective and safe drug for the acute treatment of preterm labor with minimal side effects, and it can be an option in the treatment of preterm labor, especially in patients with heart disease and multi‐fetal pregnancies.
Late-Glacial climatic changes in Eastern France (Lake Lautrey) from pollen, lake-levels, and chironomids
Authors: Peyron O. , Bégeot C. , Brewer S. , Heiri O. , Magny M. , Millet L. , Ruffaldi P. , Van Campo E. , Yu G.
Published: July 2005

High-temporal resolution analyses of pollen, chironomid, and lake-level records from Lake Lautrey provide multi-proxy, quantitative estimates of climatic change during the Late-Glacial period in eastern France. Past temperature and moisture parameters were estimated using modern analogues and ‘plant functional types’ transfer-function methods for three pollen records obtained from different localities within the paleolake basin. The comparison of these methods shows that they provide generally similar climate signals, with the exception of the Bölling. Comparison of pollen- and chironomid-based temperature of the warmest month reconstructions generally agree, except during the Bölling. Major abrupt changes associated with the Oldest Dryas/Bölling, Alleröd/Younger Dryas, and the Younger Dryas/Preboreal transitions were quantified as well as other minor fluctuations related to the cold events (e.g., Preboreal oscillation). The temperature of the warmest month increased by ∼5°C at the start of Bölling, and by 1.5°�"3°C at the onset of the Holocene, while it fell by ca. 3° to 4°C at the beginning of Younger Dryas. The comparative analysis of the results based on the three Lautrey cores have highlighted significant differences in the climate reconstructions related to the location of each core, underlining the caution that is needed when studying single cores not taken from deepest part of lake basins.
FROM PEASANT TO FARMER: A STUDY OF AGRARIAN TRANSFORMATION IN AN IRANIAN VILLAGE, 1967–2002
Authors: Ajami Amir Ismail
Published: July 2005

Iranian agriculture and rural society have undergone profound socioeconomic and political changes over the past four decades. While recognizing the significant impact of urbanization, economic development, and integration of the rural economy in the market, this paper contends that the land-reform program of the 1960s and the 1979 revolution represent the primary turning points in the rural transformation. Land reform, through intense state intervention, dramatically changed the traditional landlord-sharecropping system (nizam-i arbab-rayati). Peasant uprisings, the forcible occupation of large estates, and the agrarian policies of the postrevolutionary regime have led to the demise of the urban agricultural bourgeoisie and the empowerment of the peasants. There has been a disintegration of large-scale public and private agricultural production systems, including agribusinesses, farm corporations, and the agricultural production cooperatives developed under the shah's regime.
A REPLY TO HILAL KHASHAN
Authors: SALLOUKH BASSEL F.
Published: July 2005

Rather than respond in any meaningful way to the substance of my review of his recent book Arabs at the Crossroads, Hilal Khashan instead prefers to launch a series of personal attacks against me cloaked by knavish misrepresentations of my review. It is certainly true, as he repeatedly asserts, that he is older than I—although I am not at all clear about how that is relevant. In any event, it is never too late for anyone to learn the ethics of academic debate and dialogue. As to whether my interpretation of his analysis and methodological assumptions is valid or not, this I leave for readers to judge.
Should conservationists pay more attention to corruption?
Authors: Smith Robert J. , Walpole Matthew J.
Published: July 2005

Corruption is known to limit economic development and fuel poverty, but it may also hinder conservation efforts and contribute to biodiversity loss. Here we explore some of the ways that corruption may affect conservation. We argue that corruption has potentially significant implications that should be highlighted and tackled directly. Unfortunately, research into the topic lags behind that in other sectors and empirical studies are scarce and underdeveloped. The result is that, whilst some academics and practitioners cite corruption as a threat to biodiversity and call for efforts to increase transparency and accountability, we currently know little regarding the nature and magnitude of any effects it may have. Whilst precautionary measures can be built into conservation projects to pre-empt corruption, further research would help to shed light on this issue and aid the development of appropriate responses.
Hunting patterns in tropical forests adjoining the Hkakaborazi National Park, north Myanmar
Authors: Rao Madhu , Myint Than , Zaw Than , Htun Saw
Published: July 2005

Hunting for subsistence and trade constitute a major threat to wildlife populations within and outside protected areas in Myanmar. We examined hunting patterns in a forested landscape adjoining the Hkakaborazi National Park in north Myanmar with the aim of generating recommendations to manage hunting. The results described here focus on two issues: the significance of proximity to settlements and markets for prey abundance, and the influence of relative abundance and intrinsic preference on prey offtake. We used strip transect and camera trap surveys to generate relative abundance indices and overall encounter/capture rates for commonly hunted species at four sites that differed in their proximity to settlements and large trading towns. Questionnaires were used to obtain meal records and information on hunting. Encounter and capture rates for hunted species appear to be inversely related to proximity to villages as well as to large, commercial towns. Hunting is indiscriminate, with offtake determined largely by relative abundance rather than intrinsic preference or legislation. Specific management and policy recommendations include the need to monitor the impacts of hunting on vulnerable species, the demarcation of no-take areas, and modification of the legal framework for wildlife conservation.
Age of immersion as a predictor of foreign accent
Authors: MUNRO MILES , MANN VIRGINIA
Published: July 2005

This study examines the relationship between age of immersion (AOI) and the degree of perceived accent (DPA) that raters who speak native English perceive in the speech of Mandarin speakers who learned English as a second language. AOI and speech samples of variable length and linguistic context (single words, sentences, short paragraph, and self-generated picture narration) were collected from the target group (n=32, AOI=3–16) and from native speaker controls. A moderately trained native speaker panel of college students then rated the samples on how “native” they sounded using a continuous scale. Rating was broken over three separate sessions to relieve fatigue, and a reliability measure was administered at the onset and termination of each session to ensure consistency. Reliable performance was demonstrated both across judges and across sessions and indicated no single AOI demarcated a “critical period.” Instead, DPA was found to deviate from native in a highly linear manner with AOI, as did speakers' tendencies to noticeably deflect from this line. These deviations began at an AOI of about 5, although some speakers bottomed out with an AOI as early as 7, whereas nearly native ratings were given to others whose AOI was greater than 5. Females were rated as more native and variably accented than males. Ratings of native decreased with sampling length but increased with extemporization, the effect of AOI on DPA being similar for all sampling types.
Learning nonnative names: The effect of poor native phonological awareness
Authors: HU CHIEH-FANG , SCHUELE C. MELANIE
Published: July 2005

This research investigates the influence of phonological awareness on the learning of vocabulary in a foreign language. Thirty-seven Chinese-speaking third graders with high phonological awareness and 37 with low phonological awareness participated in multitrial word learning tasks involving nonnative sounding (English) new names paired with novel referents. The children also participated in three additional associative learning tasks: learning to associate novel native sounding names, familiar native names, and unfamiliar visual shapes with unfamiliar referents. Results indicated that children with lower phonological awareness learned both the novel nonnative names and the novel native names less accurately than children with higher phonological awareness and required more learning trials. However, these two groups did not differ in learning to associate familiar names or unfamiliar visual shapes with novel referents. The findings suggest that poor phonological awareness might slow nonnative acquisition of vocabulary via difficulty in constructing new phonological representations for new words.
The prompt hypothesis: Clarification requests as corrective input for grammatical errors
Authors: SAXTON MATTHEW , HOUSTON–PRICE CARMEL , DAWSON NATASHA
Published: July 2005

The potential of clarification questions (CQs) to act as a form of corrective input for young children's grammatical errors was examined. Corrective responses were operationalized as those occasions when child speech shifted from erroneous to correct (E→C) contingent on a clarification question. It was predicted that E→C sequences would prevail over shifts in the opposite direction (C→E), as can occur in the case of nonerror-contingent CQs. This prediction was tested via a standard intervention paradigm, whereby every 60 s a sequence of two clarification requests (either specific or general) was introduced into conversation with a total of 45 2- and 4-year-old children. For 10 categories of grammatical structure, E→C sequences predominated over their C→E counterparts, with levels of E→C shifts increasing after two clarification questions. Children were also more reluctant to repeat erroneous forms than their correct counterparts, following the intervention of CQs. The findings provide support for Saxton's prompt hypothesis, which predicts that error-contingent CQs bear the potential to cue recall of previously acquired grammatical forms.