bluuebunny/crossref_metadata_2025 huggingface dataset:
[Zn(phen)2(CX3COO)]+, X = H orCl; Influence of X on the Coordination Mode of the Carboxylate Group (phen = 1,10-Phenanthroline)
Authors: Talaei Zeanab , Morsali Ali , Mahjoub Ali R.
Published: August 2018

Two new ZnII(phen)2 complexes with trichloroacetate and acetate anions, [Zn(phen)2(CCl3COO)- (H2O)](ClO4) and [Zn(phen)2(CH3COO)](ClO4), have been synthesized and characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopy. The single crystal X-ray data of these compounds show the Zn atoms to have six-coordinate geometry. From IR spectra and X-ray crystallography it is established that the coordination of the COO− group is different for trichloroacetate and acetate. The former acts as a monodentate whereas the latter acts as a bidentate ligand.
Addition von α-Aminosäureestern an den Cycloheptadienyl-Liganden von [(η5-C7H9)Fe(CO)3]+ und den Allyl-Liganden des chiralen [(η3-C3H5)Mo(Cp)(CO)(NO)]+ / Addition of α-Amino Acid Esters to the Cycloheptadienyl Ligand of [(η5-C7H9)Fe(CO)3]+ and of the Allyl Ligand of the chiral [(η3-C3H5)Mo(Cp)(CO)(NO)]+
Authors: Urban Reinhold , Beck Wolfgang
Published: August 2018

The reactions of GlyOEt, L-AlaOMe, L-ValOMe or L-PheOMe with cycloheptadienyltricarbonyliron tetrafluoroborate afford the neutral 5-exo-amino substituted cycloheptadiene complexes [(η4-C7H9NHCHRCO2R’)Fe(CO)3] which are formed as two diastereoisomers with R = Me, CHMe2, CH2Ph. The addition of GlyOEt, L-AlaOMe or L-VaOMe to the chiral [(η3-C3H5)Mo(Cp)(CO)(NO)]BF4 gives the olefin complexes [(η2-CH2=CH-CH2- NH2CHRCO2R’)Mo(Cp)(CO)(NO)]BF4.
Heterobimetallische 3d-4f-Komplexe mit Bis(1,2-dithiooxalato)nickelat(II) als planarem Brückenbaustein / Heterobimetallic 3d-4f-Complexes with Bis(1,2-dithiooxalato)nickelate(II) as Planar Bridging Block
Authors: Siebold Matthias , Kelling Alexandra , Schilde Uwe , Strauch Peter
Published: August 2018

Planar bis(1,2-dithiooxalato)nickelates(II) react in aqueous solutions of lanthanide ions to form pentanuclear, heterobimetallic complexes of the general composition [{Ln(H2O)n}2- {Ni(dto)2}3]・xH2O (Ln = Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+; n = 4 or 5; x = 9 - 12). With [{Nd(H2O)5}2{Ni(S2C2O2)2}3]・xH2O (x = 10 - 12) (1) and [{Er(H2O)4}2{Ni(S2C2O2)2}3]・xH2O (x = 9 - 10) (2) we were able to isolate two complexes of this series as single crystals, which were characterized by X-ray structure analysis. Depending on the individual ionic radii of the lanthanide ions, the compounds crystallize in two different crystal systems with the following unit cell parameters: 1, monoclinic in P21/c with a = 11.3987(13), b = 11.4878(8), c = 20.823(2) Å , β = 98.907(9)° and Z = 2; 2, triclinic in P1̅ with a = 10.5091(6), b = 11.0604(6), c = 11.2823(6) Å , α = 107.899(4)°, β = 91.436(4)°, γ = 112.918(4)° and Z = 1. The channels and cavities appearing in the packing of the molecules are occupied by uncoordinated water molecules. High magnetic moments up to 14.65 BM./f.u. have been observed at room temperature due to the combined moments of the individual lanthanide ions.
Comparison of the Photocatalytic and Photoelectrocatalytic Decolorization of Methyl Orange on Sputtered TiO2 Thin Films
Authors: Su Yuh-Fan , Chou Tse-Chuan
Published: August 2018

Correlations between the photocatalytic and photoelectrocatalytic decolorization of methyl orange, using TiO2 thin films sputtered under various conditions, were made. Three types of systems, namely: two photocatalytic systems, one with and one without a Pt counter electrode, and a third with a Pt counter electrode having an applied potential, were used to evaluate photocatalytic activity.

The crystal structure, morphology, bandgap energy, flatband potential, and the resistances of the TiO2 films were characterized by X-ray diffraction, scanning electron microscopy, UV/vis spectroscopy, a photocurrent method, and electrochemical impedance spectroscopy, respectively. The results showed that the decolorization of methyl orange only occurred on the anode of the TiO2/Ti electrode and that the decolorization rate increased 67% when the photocatalyst was coupled to a Pt electrode (0 V applied potential), and 275% when connected with the Pt cathode and 1 V vs. Ag/AgCl applied potential. The benefits of high crystallinity, a high quantity of the anatase, and a more negative flatband potential were found in the photocatalytic reaction, whereas the resistance of the film was the main factor affecting the photoelectrocatalytic activity.
A Manganese(II) 4-Hydroxycinnamate Complex with the Tripod Ligand Tris(2-benzimidazolylmethyl)amine
Authors: Wu Huilu , Ying Wei , Yuana Jingkun , Dinga Jian
Published: August 2018

A six-coordinate manganese (II) complex with the tripod ligand tris(2-benzimidazolylmethyl) amine (ntb), with composition [Mn(ntb) (4-hydroxycinnamate)](4-hydroxycinnamate) · (DMF)0.5 · (H2O)3, was synthesized and characterized by elemental and thermal analyses, electrical conductivity, IR, and UV/vis spectral measurements. The crystal structure of the complex has been determined by the single-crystal X-ray diffraction. The Mn (II) cation is bonded to an ntb ligand and a 4-hydroxycinnamate ligand through four N atoms and two O atoms, giving a distorted octahedral coordination geometry. Cyclic voltammograms of the complex indicate a quasi-reversible Mn3+/Mn2+ couple. The X-band EPR spectrum of the complex exhibits a six-line manganese hyperfine splitting pattern with g = 2, A = 95, and confirms that the material is high-spin Mn(II).
N-(2,4,6-Trimethylborazinyl)-substituted Boron, Aluminum and Titanium Compounds
Authors: Gemünd Birgit , Günther Berndt , Knizek Jörg , Nöth Heinrich
Published: August 2018

The N-lithioborazine LiH2N3B3Me3, 1, reacts with organoboron halides not only to the respective borazinyl organylboranes but also by Me/halogen exchange. (Me2N)2B-H2N3B3Me3 was obtained from 1 and (Me2N)2BCl. A new ten-membered B6N4 ring system, 5, results on treatment of Cl(Me2N)B-B(NMe2)Cl with 1. The B-N-borazinyl borazines 6 - 8 can be prepared from 1 and B-monohalo borazines. The synthesis of 2,4,6-trimethylborazinyl-aluminum and -titanium compounds is achieved only with mononuclear monohalides of Al(III) and Ti(IV). The 2,4,6-trimethylborazinyl- bis(piperidino)alane 9 and the tris(2,6-diisopropylphenoxo)-2,4,6-trimethylborazinyltitanium 10 were characterized by X-ray structure analysis.

The distortion of the borazine ring by B and N substitution is discussed. In case of the N-substituted borazines YH2N3B3Me3 the B-N bonds of the YNB2 units are elongated, e. g. for Y = PBr2 or (RO)3Ti, while N lithiation leads to a shortening of these B-N bond. These changes of bond lengths are also reflected by changes in the B1-N2 and B3-N3 bond lengths which become shorter in the presence of electron-withdrawing groups, but longer in case of Li substitution. Also, the bond angles B1-N2-B2 and B2-N3-B3 are affected by an increase of up to 128°.
Two New Noriridoids from Scyphiphora hydrophyllacea
Authors: Zenga Yan-Bo , Meia Wen-Li , Zhaob You-Xing , Daia Hao-Fu
Published: August 2018

Chemical investigation of the EtOH extract of the aerial parts of Scyphiphora hydrophyllacea Gaertn. F. collected from Hainan resulted in the isolation of the two new noriridoids hydrophylin A (1) and hydrophylin B (2). The structures were elucidated by a study of their physical and spectral data.
Carboxyalkylcobalamins: Effects of Carboxyl Substituents on Base-on / Base-off Equilibria and Mechanochemical Co–C Bond Cleavage
Authors: Schrauzer Gerhard N. , Maciejewski-Mattson Mary L.
Published: August 2018

A series of primary and secondary carboxyalkylcobalamins with (CH2)nCOOH groups (n = 1 - 3), CH2-CH(CH3)COOH, CH(R)COOH (R = CH3, C2H5, n-C3H7), CH(CH3)(CH2)nCOOH (n = 1, 2) and CH(COOH)CH2COOH attached to cobalt were synthesized or generated in situ, mostly by the reaction of vitamin B12s or hydridocobalamin with the respective α- or ω-substituted halocarboxylic acids and reactions with olefinic carboxylic or dicarboxylic acids. Their rates of decomposition and the activation parameters ΔGo≠ , ΔHo≠ and ΔSo≠ Co-C bond cleavage were determined spectrophotometrically in aqueous solutions at different pH values. Carboxyalkylcobalamins are generally more stable in solution than comparable unsubsitituted alkylcobalamins. In secondary 1-carboxyalkylcobalamins this is attributable primarily to the inductive effect and smaller size of the carboxyl group. The presence of the carboxyl group also strengthens the axial interactions of cobalt with the 5,6-dimethylbenzimidazole (DMBZ) ligand, as evidenced through measurements of the pKa of DMBZ in these organocobalamins. Although also susceptible to spontaneous (‘mechanochemical’) decomposition, carboxyalkylcobalamins can exist with significantly longer half-lives in their base-on forms than corresponding alkylcobalamins. Short-lived, but detectable spectroscopically in solution, is succinylcobalamin, the secondary dicarboxyalkylcobalamin with a CH(COOH)CH2COOH group attached to cobalt, a compound of interest as a model of a postulated intermediate in the coenzyme B12-dependent methylmalonyl-CoA-succinyl-CoA mutase reaction
A Study on Chiral Organocalcium Complexes: Attempts in Enantioselective Catalytic Hydrosilylation and Intramolecular Hydroamination of Alkenes
Authors: Buch Frank , Harder Sjoerd
Published: August 2018

The chiral β -diketimine ligand [(S)-Ph(Me)CH-N=C(Me)]CH2 was prepared by condensation of acetylacetone with the commercially available chiral building block (S)-Ph(Me)CH-NH2. Reaction of bis(o-Me2N-α-Me3Si-benzyl)calcium with this β -diketimine led to double deprotonation. Reaction of bis(o-Me2N-α-Me3Si-benzyl)calcium with the commercially available chiral bis-oxazoline (S)-Ph-BOX gave diastereopure [(S)-Ph-BOX](o-Me2N-α-Me3Si-benzyl)calcium which in solution slowly decomposed with formation of o-Me2N-α-Me3Si-toluene. The corresponding amide complex [(S)-Ph-BOX]CaN(SiMe3)2·(THF)2 is stable and the crystal structure has been determined. In solution, this heteroleptic amide is in Schlenk equilibrium with the homoleptic species [(S)-Ph-BOX]2Ca and Ca[N(SiMe3)2]2·(THF)2. This Schlenk equilibrium can be steered to the heteroleptic side. Use of the enantiopure calcium amide catalyst for the hydrosilylation of styrene with PhSiH3 or in the intramolecular hydroamination of aminoalkenes gave good product yields, but only small ee-values were observed (5 - 10%). From stoichiometric reactions of the catalyst with the substrates it is concluded that the “true” catalytically active species is mainly present as a homoleptic calcium complex, which explains the poor enantioselectivities
Synthesis and Characterization of a Three-dimensional Porous Compound: [Cu(H2O)6][{Cu(H2O)2}2{Cu(H2O)4H4W12O42}] · 12H2O
Authors: Zhang Chun-jing , Chen Ya-guang , Shi Dong-mei , Pang Hai-jun
Published: August 2018

A novel transition metal polyoxotungstate, [Cu(H2O)6][{Cu(H2O)2}2{Cu(H2O)4H4W12O42}] · 12H2O (1), has been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analysis, IR and UV/vis spectroscopy, and TG analysis. The paradodecatungstate anions [H2W12O42]10− are linked by CuO6 octahedra, forming a three-dimensional (3D) structure. The magnetic susceptibility of compound 1 in the temperature range 2 - 300 K shows the presence of antiferromagnetic interactions within the uniform Cu2・ ・ ・Cu3 chains
A Simple Synthesis of 4-Substituted 2-(3-Hydroxy-2-oxo-1-phenethylpropylcarbamoyl) pyrrolidine-1-carboxylic Acid Benzyl Esters as Novel Cysteine Protease Inhibitors
Authors: Oh Seikwan , Jung Jae-Chul , Avery Mitchell A.
Published: August 2018

A convenient synthesis of 4-substituted 2-(3-hydroxy-2-oxo-1-phenethylpropylcarbamoyl)pyrrolidine- 1-carboxylic acid benzyl esters 17 and 18 as new cysteine protease inhibitors is described. The synthetic key strategies involve the diazocarbonyl insertion reaction of N-Boc-L-homophenylalanine (1) by diazomethane, acetylation of the bromoketone 2 with sodium acetate, and condensation of acids 12, 14 with (3S)-3-amino-2-oxo-5-phenyl-pentyl acetate monohydrochloride (4) in good yield
K2FeIII
0.5TiIII
0.5TiIV
1.0(PO4)3: Preparation and Characterization of a Langbeinite-related Phosphate Containing Iron(III) and Mixed-valent Titanium
Authors: Ogorodnyk Ivan V. , Zatovsky Igor V. , Baumer Vyacheslav N. , Slobodyanik Nikolay S. , Shishkin Oleg V. , Vorona Igor P.
Published: August 2018

A potassium mixed iron(III)-titanium(III)-titanium(IV) phosphate K2FeIII
0.5TiIII
0.5TiIV
1.0(PO4)3 has been obtained using a two-step flux interaction in evacuated sealed silica tubes. It forms tetrahedrally-shaped dark violet crystals which belong to the cubic system (space group P213) with the cell parameter a = 9.8592(5) Å . The structure was refined from single-crystal X-ray diffraction data. [MO6] octahedra and [PO4] tetrahedra share their vertices forming a rigid 3D framework. The potassium cations are located in large closed cavities of the framework. A distribution of the 3d metals’ valence states in K2FeIII
0.5TiIII
0.5TiIV
1.0(PO4)3 has been proposed on the basis of magnetic measurements, structure investigations and bond-valence calculations as well as UV/vis and EPR spectroscopy.
Two New Bis-styryl Compounds from Miliusa balansae
Authors: Huong Do Thu , Van Nguyen Thi Hong , Kamperdick Christine , Kamperdick Christine , Anh Nguyen Thi Hoang , Sung Tran Van
Published: August 2018

Two new compounds named miliubisstyryl A and miliubisstyryl B were isolated from leaves and branches of Miliusa balansae Fin. & Gagn. (Annonaceae) in addition to octacosanoic acid. Their structures were elucidated by spectroscopic methods, especially 2D NMR spectroscopy. The rare cyclobutane skeletons of these compounds are derived from a styryl compound which is also present in this plant.
New Carboxylic Acid Amides of the Pyrrole Series: Synthetic Routes and Biological Aspects
Authors: Walter Harald
Published: August 2018

Complex II inhibitors play an important role in agrochemical fungicide research and have been known for more than 40 years. With the introduction of ortho-substituted heterocyclic amides, a breakthrough in activity level and spectrum within this class was achieved. In the meantime all major agrochemical companies have entered this field. In this paper, a special complex II subclass, the pyrrole carboxamides, will be introduced in more detail and the synthesis of selected compounds as well as a short biological SAR analysis of the pyrrole subclass will be discussed.
Aniline Exchange of 2-Aryl-4,5-diphenyl-substituted Isothiazolium Salts
Authors: Wolf Janine , Sieler Joachim , Schulze Bärbel
Published: August 2018

4,5-Diphenyl-substituted N-(R1-aryl)-isothiazolium salts 4 react with anilines 2 (R2) to form 4,5- disubstituted N-(R2-aryl)-isothiazolium salts 4. The influence of donor and acceptor substituents in the N-aryl ring of 4 and in the anilines 2 on the course of the exchange was studied. The structure of the salts 4 was confirmed by a crystal structure determination of 4i.
Copper Fixation to Guaiacyl Lignin Units by Nitrogen Donor Ligands
Authors: Kozlevčar Bojan , Baškovič Polonca , Arko Aleksej , Golobič Amalija , Kitanovski Nives , Šegedin Primož
Published: August 2018

Several new copper(II) complexes with guaiacyl lignin models vanillin (HL1) [Cu(L1)2(nia)2] (1) (nia = nicotinamide) or vanillic acid (HL2) [Cu(L2)2(nia)2] (2) [Cu2(μ-L2)4(nia)2] (3), and [Cu(L2)2(Hetam)2] (4) (Hetam = ethanolamine) were isolated and characterized. The molecular structure of complex 1 reveals bidentate vanillin (HL1) coordination via the methoxy and the deprotonated hydroxy groups. On the other hand, the vanillic acid (HL2) complexes 2 - 4 show a deprotonated carboxylate group with chelating coordination mode in 2, bridging in 3 and monodentate coordination in 4. The mononuclear complexes 1, 2 and 4 show a distorted trans octahedral coordination sphere with pairs of monodentate and chelating ligands. A replacement of the monodentate nicotinamide ligand in 2 with the bidentate ethanolamine ligand in 4 changes the coordination mode of the vanillic acid anion from bidentate (complex 2) to monodentate (complex 4). This shift inside the coordination sphere reveals different O-Cu-O Jahn-Teller axes by the vanillic acid anion in 2 and ethanolamine in 4. Empty channels are present in the crystal structure of the dinuclear complex 3, stabilized by hydrogen bonds and π-π stacking.
Alkaline Earth Metal Oxyhalides Revisited – Syntheses and Crystal Structures of Sr4OBr6, Ba4OBr6 and Ba2OI2
Authors: Reckeweg Olaf , DiSalvo Francis J.
Published: August 2018

Single crystals of the compounds Ca4OCl6, Sr4OBr6, Ba4OBr6, and Ba2OI2 were obtained by solid-state reactions. The crystals of Ba2OI2 are transparent and colorless and isopointal to K2ZnO2 adopting the orthorhombic space group Ibam (no. 72, Z = 4) with the cell parameters a = 747.20(9), b = 1392.02(18), and c = 678.12(9) pm. Sr4OBr6 and Ba4OBr6 are isotypic to Ba4OCl6 (or isopointal to K6ZnO4) and crystallize in the hexagonal space group P63mc (no. 186, Z = 2) exhibiting the cell parameters a = 982.20(4) and c = 750.41(7) pm for Sr4OBr6 and a = 1030.10(2) and c = 785.92(4) pm for Ba4OBr6. In the ternary systems Ca-O-X (X = Cl, Br or I) the only compound found other than the starting materials was the already known Ca4OCl6 which is also isotypic to Ba4OCl6 crystallizing in the hexagonal space group P63mc (no. 186, Z = 2) with the cell parameters a = 903.30(6) and c = 683.27(8) pm.
The Last Missing Member of the AE2[BN2]Cl Series – Synthesis, Structural and Spectroscopic Characterization of Ba2[BN2]Cl
Authors: Reckeweg Olaf , Reiherzer Jesse , Schulz Armin , DiSalvo Francis J.
Published: August 2018

Pale grey-blue, transparent single crystals of Ba2[BN2]Cl (I4132 (no. 214), a = 1462.88(1) pm, Z = 24) are obtained by the reaction of Ba, BaCl2, BN and NaN3 in arc-welded Ta ampoules at 1200 K. The crystal structure was determined by single crystal X-ray structure analysis. The Raman and IR spectra of the title compound show the expected fundamental frequencies (νs = 1038; νas = 1969 and 2087; δ = 616 / 636 cm−1) for a nitridoborate unit with D∞h symmetry. The [N-B-N] structure obtained by X-ray single crystal structure determination corroborates this finding within the standard deviations of the measurement with d(B-N) = 132.3(8) pm and ∡ (N-B-N) = 178.5(13)°. Our results compare well to the data reported for cubic and orthorhombic Ba3[BN2]2 as well as to the isotypic compound Ba2[BN2]Br.
Structure and Properties of CeNiZn and CeAuZn
Authors: Hermes Wilfried , Mishra Ratikanta , Rodewald Ute Ch. , Pöttgen Rainer
Published: August 2018

Well crystallized samples of the intermetallic zinc compounds CeNiZn and CeAuZn were synthesized from the elements in sealed tantalum ampoules. They were investigated by X-ray diffraction on powders and single crystals. CeNiZn: ZrNiAl type, space group P6̅2m, Z = 3, a = 713.3(3), c = 388.7(1) pm, wR2 = 0.0422 for 14 refined variables and 286 F2 values; CeAuZn: TiNiSi type, space group Pnma, Z = 4, a = 719.2(2), b = 462.7(1), c = 796.5(2) pm, wR2 = 0.0403 for 20 refined variables and 467 F2 values. Magnetic susceptibility data reveal that CeNiZn is an intermediate-valent cerium compound with essentially tetravalent cerium. CeAuZn shows Curie-Weiss paramagnetism with an experimental magnetic moment of 2.51(1) μB per Ce atom and θP = −70(1) K. No magnetic ordering is observed down to 2.1 K.
Nepetolide: A New Diterpene from Nepeta suavis
Authors: Hussain Javid , Ullah Farman , Hussain Hidayat , Hussain Tasleem , Shah M. Raza
Published: August 2018

A new tricyclic clerodane-type diterpene, nepetolide (1), has been isolated from Nepeta suavis along with three known compounds namely β -sitosterol, stigmasterol, and ursolic acid. The structure elucidation of the isolated compounds was based primarily on two-dimensional (2D)-NMR techniques including correlation spectroscopy (COSY), heteronuclear multiple quantum coherence (HMQC), and heteronuclear multiple bond correlation (HMBC) experiments.
Diterpenes from Sideritis infernalis and S. candicans
Authors: Fraga Braulio M. , Bressa Carlo , Fernández Concepción , González Pedro , Guillermo Ricardo , Hernández Melchor G.
Published: August 2018

A phytochemical study of Sideritis infernalis led to the isolation of the new nor-diterpene adejone (17-nor-7α,18-dihydroxy-ent-kaur-16-one). The biosynthesis of this compound implies the decarboxylation of an epoxy-acid as the last step. In addition, three diterpenes with an ent-kaurene skeleton, episideridiol, candicandiol 7α-monoacetate and candidiol 15α-monoacetate, have been isolated from S. candicans for the first time in nature.
Synthesis, Structure and Properties of the (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 Perovskite
Authors: Ortega-San-Martin Luis , Rodgers Jennifer A. , Attfield J. Paul
Published: August 2018

The new perovskite (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 has been prepared under high pressure (10 GPa) and temperature (900 °C). The room-temperature crystal structure is described by the space group Pnma (a = 5.5702(3), b = 7.8793(5) and c = 5.5599(4) Å ) with no observed order between Bi and Sr or between Co and Ru cations. This material shows antiferromagnetic spin ordering or freezing below 50 K and a paramagnetic moment of 4.07 μB per formula unit at high temperatures, consistent with the presence of high-spin Co2+ or Co3+ ions. (Bi0.5Sr0.5)(Co0.5Ru0.5)O3 is a variable range hopping semiconductor between 40 and 300 K with a small negative magnetoresistance.
Structural Evolution of BaVS3 Under Pressure
Authors: Garg Alka B. , Vijayakumar Viswanathan , Choudhury Amitava , Hochheimer Hans D.
Published: August 2018

Results of a high-pressure angle dispersive X-ray diffraction and electrical resistance study on quasi one-dimensional BaVS3 are reported. They show that no structural transition occurs up to 26 GPa. However, there is evidence of gradual disordering indicated by the broadening of the diffraction lines. p-V data fitted to a Birch-Murnaghan equation of state yields a value of the room-temperature, ambient-pressure bulk modulus of 77.3 GPa with a pressure derivative of 4.03. It is proposed that under compression structural phase transitions resulting from static displacements of V ions that are observed at low temperature are suppressed. Instead, a partial “polymerization” of V ions that is dynamic in nature and allows enhanced hopping conduction, starts near 3 GPa and saturates above 15 GPa.
Effects of Phonon Dispersion and Anharmonicity on Thermo-physical Properties of Solids
Authors: Holzapfel Wilfried B.
Published: August 2018

Both phonon dispersion and anharmonicity contribute to the thermo-physical properties of solids in such a way that serious mistakes can be made, if these effects are not taken into account in the realization of semi-empirical equations of state (EOS) from limited experimental data sets. These effects are illustrated in comparisons of EOS data for different types of solids.
Solvothermal Synthesis of α-Quartz Powder Doped with Germanium
Authors: Largeteau Alain , Darracq Stéphane , Goglio Graziella
Published: August 2018

Experimental investigations concerning the synthesis of Si1−xGexO2 solid solutions with quartz structure have been carried out under solvothermal conditions from sol-gel preparations. The cell parameters of the powders have been determined by X-ray powder diffraction. The amount of germanium inside the SiO2 structure was measured also by electron probe micro-analysis (EPMA).
Oxokohlenstoffe und verwandte Verbindungen. 32 [1]. Über die Umsetzung von Quadratsäuredichlorid und Perchlorcyclobutenon mit SchiffBasen
Authors: Schmidt Arthur H. , Müllen Peter , Wallmeyer Gabriele , Plutniok Claudia , Wiesert Peter R.
Published: August 2018

Squaric dichloride (3) reacts with Schiff bases 5 under mild conditions to give 1 : 1 adducts 7. On recrystallisation from alcohols, these adducts are converted to the respective N-(α-alkoxybenzyl)- squaric amide chlorides 8. The reaction has been extended to perchlorocyclobutenone 4. Thus, addition products 14 have been obtained from the reaction of 4 with Schiff bases 5, which, on recrystallisation from alcohols, afforded N-(α-alkoxybenzyl)-substituted 3-amino-2,4,4-trichloro-cyclobuten- 1-ones 15. Hydrolysis of the adducts 14 gave the aminotrichlorocyclobutenones 17 in good yield.
Structural and 121Sb Mössbauer Spectroscopic Investigations of the Antimonide Oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm, Gd, Tb) and REZnSbO (RE = La, Ce, Pr)
Authors: Schellenberg Inga , Nilges Tom , Pöttgen Rainer
Published: August 2018

Quaternary antimonide oxides REMnSbO (RE = La, Ce, Pr, Nd, Sm,Gd, Tb) and REZnSbO (RE = La, Ce, Pr) were synthesized from the RESb monoantimonides and MnO, respectively ZnO, in sealed tubes at 1170 K. Single crystals were obtained from NaCl/KCl salt fluxes. The ZrCuSiAs-type (space group P4/nmm) structures of LaMnSbO (a = 423.95(7), c = 955.5(27) pm, wR2 = 0.067, 247 F2), CeMnSbO (a = 420.8(1), c = 950.7(1) pm, wR2 = 0.097, 250 F2), SmMnSbO (a = 413.1(1), c = 942.3(1) pm, wR2 = 0.068, 330 F2), LaZnSbO (a = 422.67(6), c = 953.8(2) pm, wR2 = 0.052, 259 F2), and NdZnSbO (a = 415.9(1), c = 945.4(4) pm, wR2 = 0.109, 206 F2) were refined from single crystal X-ray diffractometer data. The structures consist of covalently bonded (RE3+O2−)+ and (T2+Sb3−)− layers with weak ionic interlayer interactions. The oxygen and transition metal atoms both have tetrahedral coordination within the layers. 121Sb Mössbauer spectra of the REMnSbO and REZnSbO compounds show single antimony sites with isomer shifts close to −8 mm s−1, in agreement with the antimonide character of these compounds. PrMnSbO and NdMnSbO show transferred hyperfine fields of 8 T at 4.2 K.
Crystal Structure of the Terbium Borocarbide Tb2B2C3
Authors: Babizhetskyy Volodymyr , Mattausch Hansjürgen , Simon Arndt
Published: August 2018

The title compound was prepared from the elements by arc-melting followed by annealing in silica tubes at 1270 K for one week. The crystal structure was investigated by means of single-crystal X-ray diffraction: space group Cmmm, a = 3.412(1), b = 13.699(8), c = 3.669(1) Å, V = 171.5(1) Å3, Z = 2, R1 = 0.032; wR2 = 0.087 for 123 unique reflections with Io ≥ 2σ (Io) and 11 refined parameters.
ZrCuSiAs-type Phosphide Oxides: TbRuPO, DyRuPO, the Series LnOsPO (Ln = La, Ce, Pr, Nd, Sm), and ThAgPO
Authors: Jeitschko Wolfgang , Zimmer Barbara I. , Glaum Robert , Boonk Ludger , Rodewald Ute Ch.
Published: August 2018

The title compounds were prepared by solid-state reactions and via tin and NaCl/KCl fluxes. They crystallize with the tetragonal ZrCuSiAs-type structure (P4/nmm, Z = 2), which was refined from single-crystal X-ray data of PrOsPO (a = 402.1(1), c = 824.0(1) pm, wR2 = 0.0490, 365 F2) and ThAgPO (a = 396.1(1), c = 877.8(1) pm, wR2 = 0.0307, 314 F2). They belong to a large family of isotypic compounds, of which several, mainly fluorine doped, iron containing compounds LnFeAsO1-xFx were discovered to be superconducting with relatively high transition temperatures only recently in other laboratories. Chemical bonding in these compounds is briefly discussed, and the importance of the weakly bonding Fe-Fe interactions for the phase transitions and the superconductivity is emphasized from the viewpoint of structural chemistry. A brief account of the history of the preparation of these compounds in our laboratory is given. Originally many of these compounds were obtained only in small amounts as byproducts in the course of the preparation of ternaries.
Hydrogen-bonded Supramolecular Solids of Resorcinarenes with 4,4´-Bipyridine and 1,4-Bis(4-pyridyl)butadiyne
Authors: Wang Xiao-Ling , Liu Shu-Qun , Zhang Qian-Feng
Published: August 2018

The self-assembly of the bifunctional 4,4'-bipyridine (bipy) with bowl-shaped C-iso-butylresorcinarene (1) under two different conditions was investigated. The 0D carcerand-like capsule complex 1 · 2(bipy) · 0.5EtOH · 4H2O (3) with four stacked bipys was formed in 95% ethanol solution. The 2D wave-like layered sheet complex 1 · 2(bipy) ·CH3CN · 2H2O (4) constructed by bipy bridging 1D wave-like ribbons with hydrogen-bonded planar hexagonal rings was obtained from a wet acetonitrile solution. The multicomponent complexes 2 · 2(bpb) · MeCN (5) and 1 · (bpb) · 2MeOH (6) formed from self-assembly of 1,4-bis(4-pyridyl)butadiyne (bpb) with Cmethyl- resorcinarene (2) in acetonitrile and 1 in methanol, respectively. The structure of 5 reveals four symmetrical intermolecular O-H···N hydrogen bonds between 2 and bpb with two slightly distorted pyridine molecules, forming a wave-like chain polymer. A large extended cavity is built up to give a multicomponent molecular host which is filled with a solvent- and self-inclusion molecule as guests. The structure of 6 exhibits a pair of resorcinarene molecules side-connected to each other by two intermolecular O-H···O hydrogen bonds to form a 1D wave-like tape, which is further bridged by bpb with two perpendicular pyridines to form a 2D sheet.
Polysulfonylamine, CLXXXV. Wasserstoffbrücken oder Halogenbrücken? Die supramolekularen Strukturen von 3-Bromanilinium- und 4-Bromanilinium-di(4-brombenzolsulfonyl)amid / Polysulfonylamines, CLXXXV. Hydrogen Bonding or Halogen Bonding? The Supramolecular Structures of 3-Bromoanilinium and 4-Bromoanilinium Di(4-bromobenzenesulfonyl)amides
Authors: Lozano Virginia , Freytag Matthias , Jones Peter G. , Blaschette Armand
Published: August 2018

This study characterizes the supramolecular synthons that dominate the interionic organization of 3-bromoanilinium di(4-bromobenzenesulfonyl)amide (1) and the corresponding 4-bromoanilinium salt (2) in their respective crystal structures (1: orthorhombic, Pbca, Z´ = 1; 2: monoclinic, P21/n, Z´ = 1). Although these compounds contain N+
-H donors and C-Br groups in equal numbers, their ion packings are exclusively governed by classical, and mostly bifurcated, hydrogen bonds of the type N+
-H···O=S/N−, whereas halogen bonding C-Br···O=S/N− is absent from both structures. The isomerism of the cations, which is the only chemical difference between 1 and 2, drives the hydrogen bonds to form a network that is two-dimensional in 1, but one-dimensional in 2. The resulting layers or strands are coherently built up from hydrophilic internal regions consisting of NH3 + and (SO2)2N− groups, external hydrophobic domains of phenyl rings, and peripherically projecting bromine atoms. As the hydrophobic groups from adjacent layers or strands do not interdigitate, the bromine atoms are sterically available to form short Br・ ・ ・Br interlayer contacts of quasi-type I in 1 and inversion symmetric Br4 interstrand quadrilaterals in 2. The results of a database search for quadrilateral (C-Br)4 synthons are also presented.
Oxidation 2-substituierter Pyrrolidine und Piperidine als Nicotinanaloga / Oxidation of 2-substituted Pyrrolidines and Piperidines as Nicotine Analogues
Authors: Möhrle Hans , Berlitz Johannes
Published: August 2018

The oxidation of nicotine (1) with Hg(II)-EDTA follows the direction to the α-methylene group of the pyrrolidine part and results in a two-step dehydrogenation to lactam 3. The same course is observed with the aromatic or heteroaromatic 2-substituted compounds 4 - 7 to give the pyrrolidones 8 - 11. In contrast, the 2-methyl- or 2-methylaryl-substituted pyrrolidines 12 - 14 are attacked at the α-methine group with only a two-electron withdrawal and give rise to the iminium derivatives 15 - 17. These salts as well as the corresponding enamines show, after addition of D2O, exchange phenomena in the NMR spectra, which indicate an equilibrium in each case. The Hg(II)-EDTA dehydrogenation in the homologous piperidine series gives the corresponding results. From the anabasine derivative 18 the lactam 19 is produced, and from 2-benzyl-1-methylpiperidine (21) the iminium compound 22 is obtained.
Stepwise Aldol Addition and Cyanhydrin Formation with Acetone and Thallous Cyanide
Authors: Abu-Salem Qutaiba , Kuhn Norbert , Mallah Eyad , Meyer H.-Jürgen , Ströbele Markus , Zeller Klaus-Peter
Published: August 2018

The dithallous salt of 2,4-dihydroxy-2,4-dimethylpentanoic acid (1), formed by slow diffusion of acetone into an aqueous thallous cyanide solution, is transformed into 2,4-dihydroxy-2,4-dimethylpentanoic acid (2) by reaction with ammonium iodide. 2-Hydroxy-2,4,4-trimethylbutyrolactone (3) is obtained by treatment of 2 with catalytic amounts of benzenesulfonic acid. The sequence of the reactions and the crystal structure of 1 are discussed.
Dimeric Di(tert-butyl)haloalanes and a Monomeric Di(tert-butyl)phosphino-di(tert-butyl)alane
Authors: Krossing Ingo , Nöth Heinrich , Staude Siegfried
Published: August 2018

The di(tert-butyl)aluminum halides, tBu2AlX (X = Br, I) have been prepared in yields ranging from 55 to 64% from AlX3 and LitBu in a 1 : 2 molar ratio in pentane. In the crystal these pyrophoric compounds are dimeric featuring Al-X-Al bridges. The reaction of AlCl3 with LitBu in diethyl ether produced a volatile solvate of composition tBu3Al-Cl-AltBu2(OEt2). Reaction of this species with AlCl3 at 120 ◦C yielded a separable mixture of tBu2AlCl and tBu2AlCl(OEt2). tBu2AlCl and tBu2GaCl react with tBu2PLi to produce the monomeric compounds tBu2E-PtBu2 (E = Al, Ga). The aluminum compound decomposes at 111 °C to give a mixture of the cis/trans-isomers of [tBu(H)Al- PtBu2]2 while at 200 °C only the trans-isomer is formed.
Preparation and Crystal Structure Determination of Sulphur Dioxide Solvate Crystals with Cetyl- and Dodecyltrimethylammonium Bromide
Authors: Shopova Denitsa , Dinnebier Robert , Jansen Martin
Published: August 2018

Cetyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB) form with sulphur dioxide crystalline solvates which have been characterised by Raman spectroscopy and X-ray powder diffraction (XRPD) at room temperature. In both crystal structures, the fully extended CTAB and DTAB cations are oriented along the a axes, forming infinite parallel stacks along the b axes. Neighbouring stacks form sheets with the bromide anions and the sulphur dioxide molecules acting as chelating agents. Consecutive sheets are flipped and shifted, thus building the three-dimensional crystal structure in a brick-like manner.
Interfacial Behavior of Ferrocene- and 1,4-Naphthoquinone-based Compounds, and Their Mixtures with Monoolein at the Air/Water Interface
Authors: Tauraitė Daiva , Razumas Valdemaras , Nylander Tommy , Butkus Eugenijus
Published: August 2018

In this work, a study of the interfacial properties of redox-active novel ferrocene- and 1,4-naphthoquinone- based compounds containing an alkenyl chain is presented. The miscibility of these compounds with 1-monooleoylglycerol (monoolein, MO), a well-known and much studied substance because of its rich polymorphism in water, at the air/water interfaces was investigated by using the Langmuir surface film balance to get a better understanding of the interaction between MO and the new derivatives. The influence of temperature on the monolayer structure was also studied. It has been demonstrated that the monolayers of all compounds have a liquid-expanded structure, and that the mixed films are more stable compared to the layers of the individual compounds.
Three-component Reaction of Cycloheptanone, 6-Amino-1,3-Dimethyluracil and Aromatic Aldehydes; X-Ray Structure, and Anti-inflammatory Evaluation of the Products
Authors: Hegab Mohamed I. , Hassan Nasser A. , Abdel-Megeid Farouk M. E.
Published: August 2018

1,3-Dimethyl-5-aryl-1,6,7,8,9,10-hexahydrocyclohepta[5,6]pyrido[2,3-d]pyrimidine-2,4-diones 4a, b (the linear regioisomers) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5a, b, were isolated from a three-component reaction of cycloheptanone, 6-amino-1,3- dimethyluracil, and 4-chloro- or 4-bromobenzaldehyde. Surprisingly, 1,3-dimethyl-10-aryl-1,5,6,7, 8,9-hexahydrocyclohepta[4,5]pyrido-[2,3-d]pyrimidine-2,4-diones 6f, g (the angular regioisomers which are described for the first time in the literature under the given reaction conditions) and the Schiff bases, 6-N-benzylidenamino-1,3-dimethyluracil derivatives 5f, g, were isolated and characterized from the reaction with 4-methoxybenzaldehyde and 4-cyanobenzaldehyde. However, the three-component reaction of 6-amino-1,3-dimethyluracil, cycloheptanone, and 2-methoxybenzaldehyde afforded 1,3-dimethylbenzo[4,5]pyrido[3,2-d]pyrimidine-3,4-dione (7). Single crystal X-ray diffraction and 13C NMR studies of 4a and 6f provided support for the established structures. Some of the new products were tested for antiinflammatory activity comparable to indomethacin.
Transition of Classic Decatungstate to Paratungstate: Synthesis, Structure and Luminescence Properties of Two Paratungstate-based 3-D Compounds
Authors: Yuan Ling , Qin Chao , Wang Xinlong , Li Yangguang , Wang Enbo
Published: August 2018

Two new paratungstate-based compounds were isolated from the acetate buffer solution containing decatungstate [W10O32]4− at different reaction temperatures. The two compounds have been characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), and single crystal X-ray diffraction, and formulated as (H3O)3[{K(H2O)}2{Na2(H2O)8}2(Na0.5H2O)2(H2W12O2)] ・ 6H2O (1) and (H3O)2[{K(H2O)4}2{Na3(H2O)9}2(H2W12O42)]·2H2O (2). Compounds 1 and 2 exhibit different three-dimensional architectures with bridging sodium and potassium as countercations for the paratungstate anion. Compound 1 displays an intense blue luminescence in the solid state. The structural transformation from [W10O32]4− to [H2W12O42]10− in an acetate buffer provides a route for the synthesis of new paratungstate-based compounds.
Development of a Reference Electrode Chip for Application in Ion Sensor Arrays
Authors: Liao Wei-Yin , Chou Tse-Chuan
Published: August 2018

A reliable screen-printing technique for fabricating an Ag/AgCl reference electrode on a solid substrate in a simple two-step procedure, which allows the incorporation of four different ion-selective electrodes on a chip, is presented. A ‘sandwich’ composite structure, comprising the reference electrode and a chip, was fabricated as a junction polymer membrane having an inner electrolyte layer and an Ag/AgCl electrode supported on a ceramic substrate. The junction polymer membrane was composed of chloroprene rubber, and the electrolyte layer was formed from agar gel. The electrochemical characteristics and performance of the reference electrode when integrated into a chip were investigated. From the results, it was shown that the potential change at the reference electrode chip as a function of the chloride ion concentration and pH can be kept reliably small. Its potential was also independent of the presence of other, physiologically significant, ions such as Ca2+, K+ and Li+. The reference electrode, fabricated as a chip, can be used continuously for more than 60 h. Furthermore, its integration with four different ion-selective electrodes (potassium, sodium, ammonium, and calcium) on a substrate to form an ion sensor array chip was shown to be a facile process. The integration procedures and the sensing performances of the ion sensor array chip are also described.
Some Unsymmetrical Metal 1,2-Dithiolenes Based on Palladium, Platinum and Gold
Authors: Papavassiliou George C. , Anyfantis George C. , Terzis Aris , Psycharis Vassilis , Kyritsis Panayotis , Paraskevopoulou Patrina
Published: August 2018

The unsymmetrical complexes Pd(dpedt)(dddt), Pt(dpedt)(dddt), Pd(dpedt)(dmit), and Au(dpedt)- (dddt) (where dpedt is diphenyl-ethylenedithiolate, dddt is 5,6-dihydro-1,4-dithin-2,3-dithiolate and dmit is 1,3-dithiol-2-thione-4,5-dithiolate) were prepared and characterized. The study of their chemical and electrochemical behavior showed that they are stable in air and could be candidate materials for fabrication of field-effect transistors and other devices.
Preparation and Characterisation of Iodo-functionalised Azobenzene Derivatives of the Type I–p-C6H4–N=N–p-C6H4–X
Authors: Siemeling Ulrich , Bruhn Clemens , Meier Mario , Schirrmacher Christian
Published: August 2018

A broad range of azobenzene derivates of the general type I-p-C6H4-N=N-p-C6H4-X (1) have been prepared. In the case of X = Ph (b), C≡C-Fc (e, Fc = ferrocenyl), OMe (g), Oi-Pr (i), and NMe2 (m), these compounds have been characterised by single-crystal X-ray structure analysis. In addition, the closely related 4-dimethylamino-1-(4-iodophenylazo)naphthalene 2 and 8-(4-iodophenylazo) quinoline 3 have also been prepared. Furthermore, the ferrocene derivative Fc-C≡C-p-C6H4- NH2 (4), which served as a starting material for the synthesis of I-p-C6H4-N=N-p-C6H4-p-C6H4- C≡C-Fc (1e), was prepared and structurally characterised by X-ray diffraction.
STM Analysis of a Chiral Helical Onedimensional Nickel(II) Coordination Polymer
Authors: Alam Mohammad Sahabul , Scheurer Andreas , Saalfrank Rolf W. , Müller Paul
Published: August 2018

C2-symmetric nickel(II) salen complexes [NiL] 1 were deposited on a highly oriented pyrolytic graphite (HOPG) surface from their acetone solutions. They aggregate easily to single, segregated, homochiral polymeric chains of (M)-1D- 1
n [NiL] (2) on the substrate as also found in single crystals. In STM topography, the single helical 1D structures 2 found on the surface were in excellent agreement with the dimension of aligned dimeric aggregates of 1 obtained from X-ray crystallography. Weak intermolecular NiII...OMe coordinations (dMeO−Ni = 0.35 nm) were found to be responsible for the formation of the chiral, helical and 1D assemblies on the substrate.
Orthoamide und Iminiumsalze, LXXXVIII. Synthese N,N,N′,N′,N″,N″-persubstituierter Guanidiniumsalze aus N,N′-persubstituierten Harnstoff/Säurechlorid-Addukten**
Authors: Kantlehner Willi , Kreß Ralf , Mezger Jochen , Ziegler Georg
Published: August 2018

N,N,N′,N′,N″,N″-Hexamethylguanidinium chloride 9c was prepared by treating the reaction mixture formed from N,N,N′,N′-tetramethylurea (1a) and phthaloyl chloride (16) with dimethyltrimethylsilylamine 15. N,N,N′,N′-Tetramethyl-chloroformamidinium chloride (2a) is an intermediate in this synthesis. The chloroformamidinium chloride 2a can also be prepared by treating the urea 1a with thionyl chloride or phosphorus pentachloride, respectively. The guanidinium salt 9c can be obtained from the crude 2a thus prepared and the silylamine 15. From urea/phosphoryl chloride adducts and primary aromatic amines have been prepared guanidines 38, which are converted to N,N′-diaryl-N,N′,N″,N″-tetramethyl-guanidinium iodides 39 on treatment with methyl iodide. The N,N′,N″-trimethyl-N,N′,N″-triphenylguanidinium salt 44a was prepared from the chloroformamidinium salt 43 and N-methylaniline. The guanidinium salt 9c is the reaction product when the urea 1a/POCl3 adduct is treated with the silylamine 15.
Two copper(I) complexes of bi- (or tri-)pyrazolyl ligands featuring Cu3pz3 or Cu4pz4 motifs
Authors: Zhang Jin-Xue , Yan Ting-Ting , Kou Jun-Feng , Zhang Wen-Hua , Yang Guang
Published: August 2018

The semirigid bipyrazolyl and tripyrazolyl ligands, namely 1,4-bis((3,5-diphenyl-1H-pyrazol-4-yl)-methyl)benzene (H2L1) and 1,3,5-tris((3,5-diphenyl-1H-pyrazol-4-yl)methyl)benzene (H3L2), and their Cu(I) complexes (Cu2L1)
n
(1), Cu4(HL2)2 (2) have been prepared and structurally characterized. Single-crystal X-ray analysis demonstrates that 1 exhibits a 2D structure featuring cyclic trinuclear Cu3pz3 subunits. Complex 2 is a tetranuclear compound in which the tripyrazolyl ligand is partially deprotonated and acts as a μ
4 bridge connecting four Cu(I) atoms.
2,3-Dihydro-4,5-diisopropyl-1,3-dimethylimidazol-2-yliden und seine Chalkogenone
Authors: Göhner Martin , Kuhn Norbert , Maichle-Mößmer Cäcilia , Niquet Elke
Published: August 2018

2,3-Dihydro-4,5-diisopropyl-1,3-dimethylimidazol-2-ylidene (6) is prepared by reduction of the corresponding thion 7a with potassium. The selenium compound 7b is obtained from 6 and selenium. In the solid state, 7a and 7b exist as their isomers, as revealed by their crystal structures.
Syntheses and structural characterization of coordination polymers of Cu(II) and Zn(II) chlorobenzoates and bis(pyridin-4-yl)-substituted species
Authors: Mao Fu-Lin , Tao Jian-Qing , Dai Chun-Hua
Published: August 2018

The reaction of Cu(II) nitrate with sodium 2-chlorobenzoate (NaL1) and (E)-1,2-di(pyridin-4-yl)ethene (dpe) yields a new complex [Cu(L1)2(dpe)(H2O)] (1). When Zn(II) nitrate reacts with sodium 4-chlorobenzoate (NaL2) and 1,2-di(pyridin-4-yl)ethane (dpa), [Zn(L2)2(dpa)]·CH3OH (2) is obtained. Complexes 1 and 2 have been characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental and thermogravimetric analyses. 1 shows a 3D CdS network structure with uninodal 4-connected (65.8) topology; complex 2 displays a chain structure.
Porphyrin substituent regiochemistry, conformation and packing – the case of 5,10-diphenylporphyrin
Authors: Senge Mathias O. , Dahms Katja , Holdt Hans-Jürgen , Kelling Alexandra
Published: August 2018

5,10-Disubstituted porphyrins are more recent additions to the family of meso-substituted porphyrins. A crystallographic comparison of 5,10-diphenylporphyrin with the regioisomeric 5,15-disubstituted system reveals striking differences in their conformation. In the free base porphyrins the former uses mainly out-of-plane distortion to alleviate steric strain while in-plane core elongation predominates in the latter. In contrast, the structure of the Cu(II) complex is planar and forms strong π-π aggregates with very small lateral shifts. Macroscopically, the packing is similar to that of porphyrin sponges of the 5,10,15,20-tetraphenylporphyrin type.
Ternary aurides RE
4Mg3Au10 (RE=Y, Nd, Sm, Gd–Dy) and their silver analogues
Authors: Block Theresa , Johnscher Michael , Linsinger Stefan , Ch. Rodewald Ute , Pöttgen Rainer
Published: August 2018

The ternary aurides RE
4Mg3Au10 (RE=Y, Nd, Sm, Gd–Dy) and their silver analogues were synthesized by induction melting of the elements in sealed niobium tubes. These intermetallic phases were characterized by powder X-ray diffraction. They crystallize with the Ca4In3Au10-type structure, which, from a geometrical point of view, is a ternary ordered version of Zr7Ni10 with the rare earth and magnesium atoms ordering on the four crystallographically independent zirconium sites. The structures of crystals from three differently prepared gadolinium samples were refined from single-crystal X-ray diffractometer data: Cmca, a=1366.69(3), b=998.07(4), c=1005.54(3) pm, wR2=0.0332, 1234 F
2 values, 46 variables for Gd4.43Mg2.57Au10, a=1378.7(1), b=1005.3(1), c=1011.2(1) pm, wR2=0.0409, 1255 F
2 values, 48 variables for Gd5.50Mg1.50Au10, and a=1350.2(5), b=995.5(1), c=1009.3(1) pm, wR2=0.0478, 1075 F
2 values, 48 variables for Gd5.61Mg1.39Au10. All crystals show substantial Mg/Gd mixing on two sites. The gold atoms form a pronounced two-dimensional substructure with Au–Au distances of 278 to 297 pm in Gd4.43Mg2.57Au10. These gold blocks are condensed via magnesium atoms (278–315 pm Mg–Au). The gadolinium atoms fill larger cavities within the three-dimensional networks. The magnesium vs. gadolinium site preference is a consequence of the different coordination numbers of the cation sites. All phases show homogeneity ranges RE
4+x
Mg3–x
Ag10 and RE
4+x
Mg3–x
Au10. The influence of the synthesis conditions is briefly discussed.
Dioldehydrase: New Observations Concerning the Effect of Oxygen, Nitrous Oxide and Carbon Monoxide
Authors: Schrauzer G. N. , Seck Jane A. , Holland R. J.
Published: August 2018

Dioldehydrase (ᴅʟ-1,2-propanediol hydrolase, E. C. 4.2.1.28) apoenzyme exists in an oxidized and a reduced modification due to the presence of disulfide-or sulfhydryl groups in the vicinity of the coenzyme binding site. Both modifications yield active holoenzymes which differ with respect to their sensitivity to O2, N2O and CO.