bluuebunny/crossref_metadata_2025_split huggingface dataset:
Syntheses, Crystal Structures and Luminescent Properties of Three Inorganic‐Organic Hybrid Frameworks Constructed from 4,5‐Imidazoledicarboxylate
Authors: Wang Dong‐E , Wang Feng , Meng Xiang‐Gao , Ding Yu , Wen Li‐Li , Li Dong‐Feng , Lan She‐Ming 
Published: October 2008

AbstractThree inorganic‐organic hybrid frameworks [Mn(HIMDC)(4,4′‐bipyo)0.5(H2O)]n (1), [Cd(H2IMDC)2(2,2′‐bipyo)] (2) and [Ca(HIMDC)(H2O)2·H2O]n (3) (H3IMDC = 4,5‐imidazoledicarboxylate; 4,4′‐bipyo = 4,4′‐bipyridine‐N,N′‐dioxide; 2,2′‐bipyo= 2,2′‐bipyridine‐N,N′‐dioxide) have been hydrothermally synthesized and characterized by the elemental analyses, IR spectra, TG analysis and the single crystal diffraction. Both compounds 1 and 3 exhibit 2D layers while 2 is a monomer. It is noteworthy that compound 2 exhibits strong fluorescent emission in the solid state at room temperature.
Synthesis, Characterization and Electrochemistry of New Soluble Porphyrazine Complexes Bearing Octakis 3‐Methylbutylthio Substituents
Authors: Erdoğmuş Ali , Koca Atıf , Avcıata Ulvi , Gül Ahmet 
Published: October 2008

AbstractPorphyrazines, MPz (M = Mg, H, Ni, Zn and Co) with octakis 3‐methylbutylthio substituents have been synthesized starting with the corresponding unsaturated dicarbonitrile derivative. These new compounds have been characterized by UV‐Vis, FT‐IR, 1H NMR, MS and elemental analysis methods. Voltammetric properties of the complexes were also investigated by CV, DPV and CPC techniques. Electrochemical studies show that three reversible one electron reductions and one reversible one electron oxidation processes (two for CoIIPz) are observed for all of the complexes. The E1/2 values are similar for the H2Pz, NiIIPz and ZnIIPz derivatives with negative shift due to the different effective nuclear charges of the central metal ion. Peak to peak separations and separation between the first reduction and first oxidation couples related with the HOMO‐LUMO gap of the complexes are in harmony with the common porphyrazine complexes.
Neue Kronenether‐stabilisierte Oxoniumhalogenochalkogenate: [H3O(Dibromo‐benzo‐18‐Krone‐6)]2[Se3Br10] und [H5O2(Bis‐dibromo‐dibenzo‐24‐Krone‐8]2[Se3Br8]
Authors: Beckmann Illenora , Läge Mechtild , Krebs Bernt 
Published: October 2008

AbstractNovel Oxonium Halogenochalcogenates Stabilized by Crown Ethers: [H3O(Dibromo‐benzo‐18‐crown‐6)]2[Se3Br10] and [H5O2(Bis‐dibromo‐dibenzo‐24‐crown‐8]2[Se3Br8]Two novel complex oxonium bromoselenates(II,IV) and –(II) are reported containing [H3O]+ and [H5O2]+ cations coordinated by crown ether ligands. [H3O(dibromo‐benzo‐18‐crown‐6)]2[Se3Br10] (1) and [H5O2(bis‐dibromo‐dibenzo‐24‐crown‐8]2[Se3Br8] (2) were prepared as dark red crystals from dichloromethane or acetonitrile solutions of selenium tetrabromide, the corresponding unsubstituted crown ethers, and aqueous hydrogen bromide. The products were characterized by their crystal structures and by vibrational spectra. 1 is triclinic, space group $\rm P{\bar 1}$ (Nr. 2) with a = 8.609(2) Å, b = 13.391(3) Å, c = 13.928(3) Å, α = 64.60(2)°, β = 76.18(2)°, γ = 87.78(2)°, V = 1404.7(5) Å3, Z = 1. 2 is also triclinic, space group $\rm P{\bar 1}$ with a = 10.499(2) Å, b = 13.033(3) Å, c = 14.756(3) Å, α = 113.77(3)°, β = 98.17(3)°, γ = 93.55(3)°. V = 1813.2(7) Å3, Z = 1. In the reaction mixture complex redox reactions take place, resulting in (partial) reduction of selenium and bromination of the crown ether molecules. In 1 the centrosymmetric trinuclear [Se3Br10]2− consists of a central SeIVBr6 octahedron sharing trans edges with two square planar SeIIBr4 groups. The novel [Se3Br8]2− in 2 is composed of three planar trans‐edge sharing SeIIBr4 squares in a linear arrangement. The internal structure of the oxonium‐crown ether complexes is largely determined by the steric restrictions imposed by the aromatic rings in the crown ether molecules, as compared to complexes with more flexible unsubstituted crown ether ligands.
Platinum and Palladium Complexes Bearing New (1R,2R)‐(–)‐1,2‐Diaminocyclohexane (DACH)‐Based Nitrogen Ligands: Evaluation of the Complexes Against L1210 Leukemia
Authors: Abu–Surrah Adnan S. , Kettunen Mika , Leskelä Markku , Al‐Abed Yousef 
Published: October 2008

AbstractThe reaction of (1R,2R)‐(–)‐1,2‐diaminocyclohexane (1) [DACH] with the aldehyde (1R)‐(–)‐myrtenal (2) in MeOH afforded the bidentate diimine ligand, (1R,2R)‐(–)‐N1,N2‐bis{(1R)‐(–)myrtenylidene}‐1,2‐diaminocyclohexane (3) in a high yield. Reduction of 3 using LiAlH4 led to the formation of the desired ligand (4) (1R,2R)‐(–)‐N1,N2‐bis{(1R)‐(–)myrtenyl}‐1,2‐diaminocyclohexane. Treatment of compound 4 with K2PtCl4 or K2PdCl4 yielded the corresponding platinum(II) and palladium(II) complexes, Pt‐5 and Pd‐6, respectively. The reaction of compound 3 with K2PtCl4 gave the diimine complex Pt‐7. The cytotoxic activity of the complexes Pt‐5, Pd‐6 and Pt‐7 was tested and compared to the approved drugs, cisplatin (Cis‐Pt) and oxaliplatin (Ox‐Pt). The complexes (Pt‐5, Pd‐6 and Pt‐7) inhibit L1210 cell line proliferation with an IC50 of 0.6, 4.2, and 0.7 μL, respectively as evidenced by measuring thymidine incorporation.
Aryldimethylsilyl Modified Hypersilanes
Authors: Hauber Sven‐Oliver , Niemeyer Mark 
Published: October 2008

AbstractAryldimethylsilyl‐substituted hypersilanes ArSiMe2Hyp [Hyp =Si(SiMe3)3; Ar = Mes (3a), Bph (3b), Mph (3c), Pph (3d), Tph (3e); Dpp (3f); with Mes = 2,4,6‐Me3C6H2, Bph = 2‐PhC6H4, Mph = 2‐MesC6H4, Pph = 2′,3′,4′,5′,6′‐pentamethylbiphenyl2‐yl, Tph = 2′,4′,6′‐triisopropylbiphenyl‐2‐yl and Dpp = 2,6‐Ph2C6H3] have been synthesized by a multi‐step reaction starting from the readily available starting materials ArI and (thf)xKHyp. For this purpose the aryl iodides were first converted into the lithium aryls by lithium‐halogen exchange with n‐butyl lithium. A salt‐metathesis reaction with SiMe2Cl2 gave the corresponding arylchlorodimethylsilanes (2a–e) in excellent yields. Finally, reaction of 2a–e with (thf)xKHyp afforded the hypersilanes 3a–e in yields up to 86 %. Bis(aryldimethylsilyl)‐substituted silanes (ArSiMe2)2Si(SiMe3)2 (Ar = Mph (4c), Tph (4e)) were obtained by the reaction of 3c or 3e with KOtBu and the corresponding chlorosilanes 2c or 2e. All new compounds have been characterized by melting point, elemental analysis, 1H, 13C, and 29Si NMR spectroscopy and for selected species by IR spectroscopy or mass spectrometry. In addition, the solid‐state structures of silanes 3a–d, 3f, and 4c have been investigated by single crystal X‐ray diffraction.
Temperature‐dependent Changes of the Crystal Structure of Li2B4O7
Authors: Sennova Natalia , Bubnova R. S. , Cordier G. , Albert B. , Filatov S. K. , Isaenko L. 
Published: October 2008

AbstractThe crystal structure of Li2B4O7 was studied by single crystal X‐ray diffraction whilst the substance was cooled down from room temperature to −150 °C. The title compound crystallizes in the tetragonal, non‐centrosymmetric space group I 41cd (no. 110), a = 9.475(5) Å (r.t.), c = 10.283(6) Å (r.t.), R values for seven different data sets vary from 2.6 to 2.9 %. Low‐temperature single crystal examinations were combined with low‐temperature powder X‐ray diffraction experiments (−189 – +27 °C). The results are discussed in comparison with data earlier obtained at high temperatures (20 – 500 °C). No phase transitions or abrupt changes of the crystal structure were observed. The coordination sphere of the lithium ions is that of a distorted tetrahedron and remains almost unchanged, although the coordination number of the lithium ions decreases slightly with rising temperature, similarly to what was found for LiB3O5. An expected rigidity of the boron‐oxygen groups was confirmed. The thermal deformations of the [B4O7]2− framework occur according to the hinge mechanism. This indicates that the LiO4 chains change their winding on cooling, which leads to deformations along c.
Homo‐ and Heteropentanuclear Coordination Compounds with Td Symmetry – the Solid State Structures of [MZn4(L)4(L′)6] (M = CoII or Zn; L = chloride or acac; L′ = 1,2,3‐benzotriazolate)
Authors: Biswas Shyam , Tonigold Markus , Volkmer Dirk 
Published: October 2008

AbstractThe syntheses of homo‐ and heteropentanuclear coordination compounds with the molecular formulae [MZn4(L)4(L′)6] (M = CoII or Zn; L = chloride or acac; L′ = 1,2,3‐benzotriazolate) are reported. These compounds display a highly symmetric coordination unit consisting of a central metal ion (M = CoII or Zn) which is octahedrally coordinated by 6 tridentate benzotriazolate‐type ligands via their N(2) donor atom. The benzotriazolate ligands span the edges of an imaginary tetrahedron thus providing four coordination sites at the corners of the tetrahedron, which are then filled by four zinc ions. The coordination shell of the latter are completed by bidentate acetylacetonate (acac) ligands or by chloride anions, respectively.The solid state structures of two homopentanuclear metal complexes, namely [Zn5(acac)4(bta)6]·4C6H12 (1) (acacH = acetylacetone; btaH = 1,2,3‐benzotriazole), and [Zn5Cl4(Me2bta)6]·2DMF (2) (Me2btaH = 5,6‐dimethyl‐1,2,3‐benzotriazole) were determined by single crystal X‐ray structure analysis. The heteropentanuclear metal complex [CoIIZn4Cl4(Me2bta)6]·2DMF (3) is isostructural with compound 2. Compound 1 was synthesized from stoichiometric amounts of Zn(acac)2 and btaH employing dichloromethane as solvent. The synthesis of compound 2 requires addition of an auxiliary base to the DMF solution of anhydrous ZnCl2 and Me2btaH. For compound 3 a stoichiometric ratio of Co(NO3)2·6H2O, anhydrous ZnCl2 and Me2btaH was employed during synthesis. Phase purity of all compounds was proved by X‐ray powder diffraction (XRPD) analysis, IR spectroscopy, and elemental analysis. Crystal data: for 1 (C80H100N18O8Zn5): monoclinic, space group P21/c with a = 23.781(5) Å, b = 16.000(3) Å, c = 25.170(5) Å, β = 115.29(3)°, V = 8659(3) Å3, Z = 4, ρ = 1.357 g cm−3. For 2 (C54H62Cl4N20O2Zn5): cubic, space group $Fd{\bar 3}m$ with a = 23.367(3) Å, V = 12759(3) Å3, Z = 8, ρ = 1.553 g cm−3. For 3 (C54H62Cl4CoN20O2Zn4): cubic, space group $Fd{\bar 3}m$ with a = 23.443(3) Å, V = 12884(3) Å3, Z = 8, ρ = 1.532 g cm−3.
Electrocrystallization of Tetra‐ and Hexa‐coordinated Silver(II) Compounds Based on 4,4′‐Dimethyl‐2,2′‐Bipyridine Ligand – Single Crystal Structures and Magnetic Studies
Authors: Kandaiah Sakthivel , Peters Eva‐Maria , Jansen Martin 
Published: October 2008

AbstractIn this paper we report on the potential dependent electrocrystallization of [Ag(4,4′‐dimethyl‐2,2′‐bipyridine)2(NO3)2] (1) and Ag(4,4′‐dimethyl‐2,2′‐bipyridine)(NO3)2 (2) from the same electrolytic bath. Thus it has been shown for the first time that the coordination number of silver ion to ligands can be tuned by the electrocrystallization potential. The single crystal structure analysis [1: C2/c, a = 18.6308(15), b = 14.5708(12), c = 11.5867(10) Å, β = 126.5910(10)°, Z = 4, R = 3.9 %] [2: P21/c, a = 8.5865(11) b = 11.0157(14) c = 16.4554(10) Å, β = 111.102(10), Z = 4 , R = 3.5 %] show divalent silver to be in an approximately square planar surrounding. Both complexes are paramagnetic following Curie's law with magnetic moments of 1.86 μB and 1.72 μB respectively.
Probing the Reactivity of the Potent AgF2 Oxidizer. Part 2: Inorganic Compounds
Authors: Malinowski Przemysław , Mazej Zoran , Grochala Wojciech 
Published: October 2008

AbstractThe reactivity of AgIIF2 towards forty two inorganic compounds containing oxo‐ and chloro‐ ligands, has been investigated. Five families of compounds were studied: (i) binary oxides of metals and nonmetals, (ii) ternary salts of inorganic oxo acids, (iii) concentrated or anhydrous oxo‐ acids, (iv) binary and ternary chlorides and (v) oxochlorides. At low temperatures up to 200 °C AgF2 readily oxidizes HgO, B2O3, PbO2, As2O5, Ag2SO4, LiBO2, K2CO3, KVO3, Ag2WO4, and AgMnO4 with concomitant oxygen evolution. In the same conditions V2O5, CrO3, MoO3, WO3, CuO, Tl2O3, I2O5, Re2O7, K2SO4, HgSO4, KSO3F, KNO3, KClO4, KIO4, BaCrO4, KMnO4 and KReO4 resist the action of AgF2 but many of these compounds get oxidized at higher temperatures (up to nearly 300 °C). Substantial inertness of sulfates, chromates, nitrates, perchlorates, permanganates and perrhenates suggests that one might attempt to synthesize salts of divalent silver with these anions. AgF2 vigorously reacts with H2SO4 (fuming, 30% SO3), HSO3Cl (100%), HClO4 (70%), and HNO3 (fuming, 100%) at room temperature yielding salts of AgI and O2; for HClO4 and HNO3 pre‐cooled to −35 °C metastable perchlorate / nitrate complexes of AgII are obtained. Anhydrous HSO3F behaves similar to HSO3CF3 (see Part 1 of this series) yielding slow methathetical conversion of AgF2 without concomitant redox reaction.Majority of chlorides and oxochlorides studied (AgCl, AuCl3, KAuCl4, WCl6, WOCl4, MoOCl4, MoO2Cl2) react with AgF2 at temperatures below 160 °C. Reaction with SiCl4 (in contrast to CCl4) is violent and very exothermic at room temperature. Liquid CrO2Cl2 (at room temperature) and solid WO2Cl2 (up to 180 °C) are kinetically inert to AgF2. We do not observe intercalation of AgF2 with various redox—inert oxo‐ and chloro‐ Lewis bases at the experimental conditions.
Siloxanediolates of the Rare Earth Elements – An Eight‐Membered Inorganic Ring System containing Ytterbium
Authors: Gießmann Stephan , Blaurock Steffen , Edelmann Anja , Lorenz Volker , Edelmann Frank T. 
Published: October 2008

AbstractTreatment of anhydrous YbCl3 with LiN(SiMe3)2 followed by reaction with 1 equivalent of 1,1,3,3,5,5‐hexaphenyl‐1,3,5‐trisiloxanediol afforded the first mono(trisiloxanediolate) complex of a rare earth element. The compound [Ph2Si(OSiPh2O)2]Yb(THF)(μ‐Cl)3Li2(THF)3 (1) was isolated in the form of colorless crystals in very high yield (93%). A single‐crystal X‐ray diffraction study confirmed the presence of an eight‐membered inorganic ring system containing ytterbium. Coordination of one THF ligand and retention of two equivalents of lithium chloride lead to formation of an “ate” complex.
Synthese und Koordinationsverhalten von (Ph3SnO)3As. Die Kristallstrukturen von (Ph3SnO)3As und [{(Ph3SnO)3As}Fe(CO)4]
Authors: Herntrich Tobias , Merzweiler Kurt 
Published: October 2008

AbstractSynthesis and Coordination Behaviour of (Ph3SnO)3As. The Crystal Structures of (Ph3SnO)3As and [{(Ph3SnO)3As}Fe(CO)4](Ph3SnO)3As (1) was obtained from the reaction of Ph3SnOH with As2O3 in a dichloromethane/water mixture as solvent. Upon recrystallization from DMF 1 forms orthorhombic crystals, space group P212121, with a = 977.3(2), b = 1903.5(3) and c = 2600.9(5) pm (at 220 K). In 1 the As atom is bound to three OSnPh3 groups with As–O distances of 171.9(3)–174.9(3) pm. Reaction of 1 with Fe2(CO)9 gives [{(Ph3SnO)3As}Fe(CO)4] (2). 2 crystallizes monoclinic, space group P21/n with a = 2242.3(5), b = 1112.6(2), c = 2353.0(5) pm and β = 111,46(2)° (at 220 K). In 2 the iron atom exhibits a trigonal bipyramidal coordination with the (Ph3SnO)3As ligand in an axial position. The Fe–As bond length is 230.5(1) pm.
Structural and Spectroscopic Studies of [M((x)tu)4]+ Systems (M = Cu, Ag; (x)tu = (substituted) Thiourea)
Authors: Bowmaker Graham A. , Pakawatchai Chaveng , Skelton Brian W. , Thanyasirikul Yupa , White Allan H. 
Published: October 2008

AbstractIn a low‐temperature redetermination of improved precision of the structure of [Cu(tu)4]2(SiF6) (‘tu’ = thiourea, SC(NH2)2), Cu–S range between 2.3173–2.3433(8), < > 2.336(11) Å, with S–Cu–S 92.72(3)–118.75(12)°. The first structure determination of a 1:4 adduct of a silver(I) salt with a (substituted) thiourea ligand is also reported, for silver(I) nitrate with ‘ethylenethiourea’, (‘etu’ = SC(NHCH2)2), as a monohydrate [Ag(etu)4](NO3)·H2O, wherein Ag–S range between 2.544–2.637(2), < > 2.59(4) Å, S–Ag–S 87.88–117.57(7)°. Bands in the far‐IR spectra of these compounds are assigned to ν(MS) modes, and the frequencies are compared with those predicted by previously established correlations between ν(MS) and the M–S bond length d(MS) for copper or silver complexes with tu or etu ligands.
Three‐dimensional Hemidirected Mixed‐ligand Lead(II) Coordination Polymer, [Pb2(bpa)2(SCN)3(NO3)]n (bpa = 1,2‐di(4‐pyridyl)ethane)
Authors: Abedini Jafar , Morsali Ali , Zeller Matthias 
Published: October 2008

AbstractA new 3D hemidirected mixed‐ligand lead(II) coordination polymer with the ligand 1,2‐di(4‐pyridyl)ethane bpa) and the two metal coordinated anions nitrate and thiocyanate, [Pb2(bpa)2(SCN)3(NO3)]n (1), has been synthesized and characterized by CHN elemental analysis, IR‐, 1H‐ and 13C NMR spectroscopy. The single crystal X‐ray data of compound 1 show that the complex is a three‐dimensional coordination polymer with two different Pb atoms with stereoactive electron lone pairs and six‐ and five‐coordinate hemidirected geometries, respectively.
Unusual Solid Solutions in the System Ge‐Sb‐Te: The Crystal Structure of 33R‐Ge4−xSb2−yTe7 (x, y ≈ 0.1) is Isostructural to that of Ge3Sb2Te6
Authors: Schneider Matthias N. , Oeckler Oliver 
Published: October 2008

AbstractWhereas for a series of layered compounds with the general formula (GeTe)n(Sb2Te3)m the stoichiometry allows to predict the structure type and the average thickness of the hexagonal atom layers, these rules are not generally applicable for GeTe‐rich compounds like Ge4Sb2Te7. A 39R layer stacking is expected, however, single crystal diffraction studies reveal a 33R layered structure ($R{\bar 3}m$, a = 4.1891(5) Å, c = 62.169(15), R = 0.047) closely related to that of Ge3Sb2Te6. This is also corroborated by the average layer thickness that can be determined from the strong reflections of powder patterns and exhibits a direct relation to the structure type. Mixed occupancy of cation positions with Ge and Sb and possibly defects allow this unusual range of homogeneity. Bulk material of the kinetically stable compound can be synthesized by quenching stoichiometric melts of the pure elements and subsequent annealing.
Atomistic Simulation Study of Cu0.327Ni0.673 Alloys: from Solid Solution to Phase Segregation
Authors: Zahn Dirk , Haarmann Frank , Grin Yuri 
Published: October 2008

AbstractWe present a combined Monte‐Carlo/molecular dynamics study of a Cu0.327Ni0.673 alloy system. On the basis of nearest‐neighbor coordination number analyses atomic clustering and phase segregation is explored. Along this line, free energy profiles are calculated and separated into entropic and energetic contributions. The competition of both terms was found in accordance to the experimental phase diagrams (phase separation of the solid solution below about 600 Kelvin). Two independent simulation runs were performed. At 1000 Kelvin the observed configurations correspond to solid solutions exhibiting a weak tendency to cluster atoms of identical species. At room temperature the energetic favoring of atomic separation is clearly dominant and leads to the formation of Ni‐rich and Cu‐rich domains. The latter are separated by interfacial regions whose width ranges from 0.5 to 1 nanometers.
Koordinationspolymere aus Metallotripyrrinen
Authors: Bröring Martin , Prikhodovski Serguei 
Published: October 2008

AbstractDieser Forschungsbericht behandelt jüngere Entwicklungen in der Koordinationschemie von Tripyrrinen und verwandten Liganden mit einem Schwerpunkt auf der Strukturchemie von Koordinationspolymeren. Der Tripyrrinligand ist einzigartig in seiner Fähigkeit, ein‐ und dreidimensionale supramolekulare Strukturen aus pentakoordinierten Übergangsmetallionen zu stabilisieren. Dies gelingt durch eine effektive sterische Blockierung der sechsten Koordinationsstelle am chelatisierten Ion. Lineare Koordinationspolymere wurden mit einer Vielzahl anionischer Brückenliganden wie Trifluoracetat, Azid, Thio‐ und Selenocyanat sowie mit Pseudohalogeniden höherer Ordnung erhalten. Der Einsatz von Cyanidometallaten erlaubt zudem die Darstellung homo‐ und heterodimetallischer Spezies, die in zwei Fällen strukturell charakterisiert wurden. Neben den kovalenten koordinativen Bindungen wurden verschiedene sekundäre Wechselwirkungen wie Wasserstoffbrückenbindungen oder π‐Stapelkontakte als stabilisierende Zusatzelemente gefunden, die eine Darstellung von Materialien mit funktionalisierten inneren Oberflächen ermöglichen.
Kinetische Untersuchungen zur Hydrierung von Kohlendioxid zu Ameisensäure mit einem Rhodiumkomplex als Katalysator
Authors: Dietrich Jens , Schindler Siegfried 
Published: October 2008

AbstractKinetic Studies on the Hydrogenation of Carbon Dioxide to Formic Acid using a Rhodium Complex as CatalystA detailed kinetic analysis has been performed on the hydrogenation of carbon dioxide with the complex [(dppp)2RhH] (dppp = 1,3‐bis(diphenyl‐phosphino)propane in DMSO using stopped‐flow techniques. Activation parameters including the activation volume for this reaction as well as for the related reaction of the formation of the dihydrogen complex [(dppp)2RhH2]HCO2 were obtained and thus allowed the formulation of a mechanism for this reaction cycle.
Structural and Spectroscopic Evidence for Marginal Metal‐to‐Ligand Charge Transfer in Complexes Pt(abpy)Me3X, abpy = 2,2′‐Azobispyridine, X = Cl, Br, I
Authors: Dogan Akbey , Kavakli Cüneyt , Sieger Monika , Niemeyer Mark , Sarkar Biprajit , Kaim Wolfgang 
Published: October 2008

AbstractThe title complexes (X = Cl, 1a; X = Br, 1b; X = I, 1c) could be characterized by 1H‐NMR spectroscopy and were partially studied by X‐ray diffraction (1b,c), cyclic voltammetry and UV‐Vis spectroscopy (1b). The short N=N bonds of about 1.26Å, the occurrence of only weak charge transfer absorptions in the visible, the rather small shift of the reduction potential, and the small g anisotropy in the EPR spectrum of 1b˙− indicate an only a marginal π interaction between the organometallic PtIV fragments and the excellent π acceptor abpy.
Die Kristallstrukturen von [Ph3PMe]Cl·CH2Cl2, [Ph4P]NO3·CH2Cl2 und [Ph4P]2[SiF6]·CH2Cl2
Authors: Neumüller Bernhard , Dehnicke Kurt 
Published: October 2008

AbstractCrystal Structures of [Ph3PMe]Cl·CH2Cl2, [Ph4P]NO3·CH2Cl2, and [Ph4P]2[SiF6]·CH2Cl2The crystal structures of the title compounds are determined by X‐ray diffraction. In all cases, the included dichloromethane molecules as well as the phosphonium cations are involved to form hydrogen bridges with the anions.[Ph3PMe]Cl·CH2Cl2 (1): Space group $P{\bar 1}$, Z = 2, lattice dimensions at 100 K: a = 890.3(1), b = 988.0(1), c = 1162.5(1) pm, α = 106.57(1)°, β = 91.79(1)°, γ = 92.60(1)°, R1 = 0.0253.[Ph4P]NO3·CH2Cl2 (2): Space group P21/n, Z = 4, lattice dimensions at 193 K: a = 1057.0(1), b = 1666.0(1), c = 1358.9(1) pm, β = 100.10(1)°, R1 = 0.0359.[Ph4P]2[SiF6]·CH2Cl2 (3): Space group $P{\bar 1}$, Z = 2, lattice dimensions at 193 K: a = 1063.9(1), b = 1233.1(1), c = 1782.5(2) pm, α = 76.88(1)°, β = 83.46(1)°, γ = 72.29(1)°, R1 = 0.0332.
Tt‐Tt (Tt = Si, Ge) Dumb‐Bell Structures at Different Valence Electron Concentrations: Ln2MgSi2 (Ln = La, Ce), Yb2Li0.5Ge2, and Yb1.75Mg0.75Si2
Authors: Xie Qinxing , Kubata Christof , Wörle Michael , Nesper Reinhard 
Published: October 2008

AbstractThe isostructural compounds Yb2MgSi2, La2.05Mg0.95Si2, and Ce2.05Mg0.95Si2, as well as Yb2Li0.5Ge2 and Yb1.75Mg0.75Si2, respectively, were synthesized from stoichiometric mixtures of the corresponding elements in sealed Nb‐ ampoules under argon atmosphere. The structures were determined by single crystal X‐ray diffraction: Yb2MgSi2 (P4/mbm (No. 127), a = 7.056(1), c = 4.130(1) Å3, Z = 2), La2.05Mg0.95Si2 (P4/mbm, a = 7.544(1), c = 4.464(1) Å3, Z = 2), and Ce2.05Mg0.95Si2 (P4/mbm, a = 7.425(1), c = 4.370(1) Å3, Z = 2), Yb2Li0.5Ge2 (Pnma (No. 62), a = 7.0601(6), b = 14.628(1), c = 7.6160(7) Å, V = 786.5Å3, Z = 4), Yb1.75Mg0.75Si2 (Pnma, a = 6.9796(1), b = 14.4009(1), c = 7.5357(1) Å, V = 757.43(2) Å3, Z = 4). All compounds contain exclusively Tt‐Tt dumb‐bells (Tt = Si, Ge). The Si‐Si Zintl anions exhibit only very small variations of bond lengths which seem to be more due to cation matrix effects than to effective bond orders.