Zur Kristallstruktur von Rb2C2 und Cs2C2

On the Crystal Structure of Rb₂C₂ and Cs₂C₂ By reaction of rubidium or caesium solved in liquid ammonia with acetylene AC₂H with A = Rb, Cs was obtained, which was subsequently converted into the binary acetylide A₂C₂ in vacuum at temperatures of 520 K (Rb₂C₂) and 470 K (Cs₂C₂) using a surplus of the respective alkali metal. The crystal structures of the very air sensitive compounds were solved and refined by a combination of both neutron and X‐ray powder diffraction data. Rb₂C₂ as well as Cs₂C₂ coexist in two modifications. The hexagonal modification (P 6 2m, Z = 3) crystallises in the known Na₂O₂ structure type with two crystallographic independent sites for the C₂^2– dumbbells. For the orthorhombic modification (Pnma, Z = 4) a new structure type was found, which is related to the PbCl₂ structure type with ordered C₂^2– dumbbells occupying the Pb sites. Temperature dependent investigations between 4 K and the decomposition temperature by the means of neutron and X‐ray powder diffraction resulted in a very complex dynamic disorder of the C₂ dumbbells, which is still not completely understood. The frequencies of the C–C stretching vibration determined by the help of Raman spectroscopy fit nicely to the results obtained for other alkali metal acetylides and alkali metal hydrogen acetylides. These results seem to indicate that the electronegativity of the alkali metal has a strong influence on the frequency of the C–C stretching vibration.     

Syntheses,characterization and anti‐microbial activities of palladium(II) and palladium(IV) complexes of 3,10‐C‐meso‐Me8[14]diene (L1) and its reduced isomeric anes (LA,LB and LC). Crystal and molecular structure of [PdL1][Pd(SCN)4]

The reactions of 3,10‐C‐meso‐3,5,7,7,10,12,14,14‐octamethyl‐1,4,8,11‐tetraazacyclotetradecadiene, L¹, and two isomers (L_B and L_C, differing in the orientation of methyl groups on the chiral carbon atoms) of its reduced form with PdCl₂ and K₂[Pd(SCN)₄], produce square‐planar tetrachloro‐ and tetrathiocyano‐palladium(II) complexes of general formulae [PdL′][PdCl₄] and [PdL′][Pd(SCN)₄] (L′ = L¹, L_B and L_C), respectively. By contrast, the third ane isomer, L_A, upon reaction with the same reagents, PdCl₂ and K₂[Pd(SCN)₄], formed octahedral tetrachloro‐ and tetrathiocyanato‐palladium(IV) complexes [PdL_ACl₂]Cl₂ and [PdL_A(SCN)₂](SCN)₂, respectively. The [PdL′][PdCl₄] and [PdL_ACl₂]Cl₂ complexes undergo substitution reactions with KSCN to form square‐planar and octahedral tetrathiocyanato complexes [PdL′][Pd(SCN)₄] and [PdL_A(SCN)₂](SCN)₂, respectively. All complexes have been characterized on the basis of analytical, spectroscopic, conductometric and magnetochemical data. The anti‐fungal and anti‐bacterial activities of these complexes have been studied against some phytopathogenic fungi and bacteria. The crystal structure of [PdL¹][Pd(SCN)₄] has been confirmed by X‐ray crystallography and shows with square‐planar PdN₄ and PdS₄ geometries [monoclinic, space group C2/c, a = 17.884(3) Å, b = 14.734(2) Å, c = 11.4313(18) Å, β = 104.054(5)° ]. Copyright © 2008 John Wiley & Sons, Ltd.     

Methyl 2‐acetamido‐2‐deoxy‐β‐d‐glucopyranoside dihydrate and methyl 2‐formamido‐2‐deoxy‐β‐d‐glucopyranoside

Methyl 2‐acetamido‐2‐deoxy‐β‐d ‐glucopyranoside (β‐GlcNAcOCH₃), (I), crystallizes from water as a dihydrate, C₉H₁₇NO₆·H₂O, containing two independent molecules [denoted (IA) and (IB)] in the asymmetric unit, whereas the crystal structure of methyl 2‐formamido‐2‐deoxy‐β‐d ‐glucopyranoside (β‐GlcNFmOCH₃), (II), C₈H₁₅NO₆, also obtained from water, is devoid of solvent water molecules. The two molecules of (I) assume distorted ⁴C₁ chair conformations. Values of ϕ for (IA) and (IB) indicate ring distortions towards B_C2,C5 and ^C3,O5B, respectively. By comparison, (II) shows considerably more ring distortion than molecules (IA) and (IB), despite the less bulky N‐acyl side chain. Distortion towards B_C2,C5 was observed for (II), similar to the findings for (IA). The amide bond conformation in each of (IA), (IB) and (II) is trans, and the conformation about the C—N bond is anti (C—H is approximately anti to N—H), although the conformation about the latter bond within this group varies by ∼16°. The conformation of the exocyclic hydroxymethyl group was found to be gt in each of (IA), (IB) and (II). Comparison of the X‐ray structures of (I) and (II) with those of other GlcNAc mono‐ and disaccharides shows that GlcNAc aldohexopyranosyl rings can be distorted over a wide range of geometries in the solid state.     

Synthesis,Characterization and Crystal Structure of Novel Mixed Bridged Trinuclear Oxo‐Centered Iron(III), Chromium(III) Complexes Containing Terminal Unsaturated Carboxylato and Acrylic Acid Dimer Anion Ligands

Three new oxo‐centered trinuclear mixed‐bridged carboxylate complexes with terminal unsaturated ligands ([M₂M′(μ₃‐O)(μ‐O₂C₃H₃)₅(μ‐O₄C₆H₇)(O₂C₃H₃) (H₂O)₂]·2H₂O [M = Fe, M′ = Fe ( 1 ); M = Fe, M′ = Cr ( 2 ); M = Cr, M′ = Fe ( 3 )]) have been synthesized and characterized by means of elemental analyses, IR spectra and crystal structure analyses. The compounds crystallize isotypically in the orthorhombic space group type Pbcn with a = 24.622(3) Å, b = 16.304(2) Å, c = 17.491(2) Å, V = 7021.5(15) ų ( 1 ), a = 24.708(5) Å, b = 16.290(2) Å, c = 17.394(2) Å, V = 7001.0(18) ų ( 2 ), a = 24.611(4) Å, b = 16.300(3) Å, c = 17.359(3) Å, V = 6964(2) ų ( 3 ), and Z = 8. The infrared spectra show resolved bands arising from ν_asym(OCO) and ν_sym(OCO) vibrations of monodentate and bridging carboxylate ligands along with those of ν_asym(M₂M′O) vibrations in the complexes.     

1‐(β‐d‐Erythrofuranosyl)adenosine

The title compound, also known as β‐erythroadenosine, C₉H₁₁N₅O₃, (I), a derivative of β‐adenosine, (II), that lacks the C5′ exocyclic hydroxymethyl (–CH₂OH) substituent, crystallizes from hot ethanol with two independent molecules having different conformations, denoted (IA) and (IB). In (IA), the furanose conformation is ^OT₁–E₁ (C1′‐exo, east), with pseudorotational parameters P and τ_m of 114.4 and 42°, respectively. In contrast, the P and τ_m values are 170.1 and 46°, respectively, in (IB), consistent with a ²E–²T₃ (C2′‐endo, south) conformation. The N‐glycoside conformation is syn (+sc) in (IA) and anti (−ac) in (IB). The crystal structure, determined to a resolution of 2.0 Å, of a cocrystal of (I) bound to the enzyme 5′‐fluorodeoxyadenosine synthase from Streptomyces cattleya shows the furanose ring in a near‐ideal ^OE (east) conformation (P = 90° and τ_m = 42°) and the base in an anti (−ac) conformation.     

State‐state transitions for CCl2(X1A1, A1B1, a3B1) radical and collisional quenching of CCl2(A1B1 and a3B1) by O2, N2, NO,N2O,NH3, and various aminated molecules

CCl₂ free radicals were produced by a pulsed dc discharge of CCl₄ in Ar. Ground electronic state CCl₂(X) radicals were electronically excited to the A¹B₁ (0,4,0) vibronic state with an Nd:YAG laser pumped dye laser at 541.52 nm. Experimental quenching data of excited CCl₂(A¹B₁ and a³B₁) by O₂, N₂, NO, N₂O, NH₃, NH(CH₃)₂, NH(C₂H₅)₂, and N(C₂H₅)₃ molecules were obtained by observing the time‐resolved total fluorescence signal of the excited CCl₂ radical in a cell, which showed a superposition of two exponential decay components under the presence of quencher. The quenching rate constants k_A of CCl₂(A) state and k_a of CCl₂(a) state were derived by analyzing the experimental data according to a proposed three‐level model to deal with the CCl₂(X¹A₁, A¹B₁, a³B₁) system. The formation cross sections of complexes of electronically excited CCl₂ radicals with O₂, N₂, NO, N₂O, NH₃, and aminated molecules were calculated by means of a collision‐complex model. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 34: 351–356, 2002     

Zur Abgrenzung der PbFCl‐ und Cu2Sb‐Strukturfamilien: Neubestimmung und Verfeinerung der Kristallstrukturen von CuMgSb,Cu2Sb und CuMgAs

Demarcation of the PbFCl and Cu₂Sb Structure Families: Crystal Structure Re‐Determinations and Refinements of CuMgSb, Cu₂Sb, and CuMgAs The crystal structures of CuMgSb, Cu₂Sb, and CuMgAs have been re‐determined and refined from single crystal data, and the structural relationship between CuMgSb (cubic), Cu₂Sb (tetragonal) and CuMgAs (orthorhombic) is discussed in detail. CuMgAs does not crystallize in the Cu₂Sb type, as assumed until now; but in a new structure type oP24 (Pnma; Z = 8): a = 1346.0(1) pm, b = 395.40(3) pm, c = 739.58(6) pm. The structure is related to Cu₂Sb and can be derived from it following the principle of ′chemical twinning′. The re‐determined parameters of Cu₂Sb are included in a structure field diagram together with additional representatives of the PbFCl type. The structure field can be devided into three regions with the prototypes PbFCl, Cu₂Sb, and Fe₂As, respectively. The assignment can be related to the predominant type of bonding of each structure.     

A new one‐dimensional ZnII coordination polymer based on 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole and benzene‐1,2‐dicarboxylate

Multidentate N‐heterocyclic compounds form a variety of metal complexes with many intriguing structures and interesting properties. The title coordination polymer, catena‐poly[zinc(II)‐bis{μ‐2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole}‐κ²N³:N^3′;N^3′:N³‐zinc(II)‐bis(μ‐benzene‐1,2‐dicarboxylato)‐κ²O¹:O²;κ³O¹,O^1′:O²], [Zn₂(C₈H₄O₄)₂(C₁₁H₁₀N₄)₂]_n, has been synthesized by the reaction of Zn(NO₃)₂ with 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole (imb) and benzene‐1,2‐dicarboxylic acid (H₂bdic) under hydrothermal conditions. There are two crystallographically distinct imb ligands [imb(A) and imb(B)] in the structure which adopt very similar coordination geometries. The imb(A) ligand bridges two symmetry‐related Zn1 ions, yielding a binuclear [(Zn1)₂{imb(A)}₂] unit, and the imb(B) ligand bridges two symmetry‐related Zn2 ions resulting in a binuclear [(Zn2)₂{imb(B)}₂] unit. The above‐mentioned binuclear units are further connected alternately by pairs of bridging bdic²⁻ ligands, forming an infinite one‐dimensional chain. These one‐dimensional chains are further connected through N—H...O hydrogen bonds, leading to a two‐dimensional layered structure. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.     

Well‐Defined Amphiphilic C60‐PEG Conjugates: Water‐Soluble and Thermoresponsive Materials

For the preparation of well‐defined H₂O‐soluble C₆₀ polymers, several C₆₀‐PEG conjugates were prepared from a C₆₀ biscarboxylic acid derivative and monodisperse NH₂‐PEGs (NH₂‐EG_n, n = 4 – 36) via amide conjugation. When the relatively long PEGs (EG_n, n ≥ 12) were employed, the C₆₀‐PEG conjugates became completely H₂O‐soluble by forming micelle‐like structure shown by the data of surface tension, DLS, and cryo‐TEM. Interestingly, these H₂O‐soluble C₆₀‐PEG conjugates (C₆₀(EG_n)₂, n = 12 – 36) showed reversible thermoresponse to form larger aggregates (ca. 1 μm by DLS) at higher temperatures. The temperature for the aggregation was related to the lengths of PEGs attached to C₆₀; 29 °C (C₆₀(EG_n)₂, n = 12), 51 °C (n = 20), and 72 °C (n = 36). This thermoresponse was speculated to occur by dehydration of well‐organized PEG chains in the micelle‐type structure of monodisperse C₆₀‐PEG caused by gauche‐to‐anti conformational change of PEG anchors. This thermoresponse of well‐defined amphiphilic C₆₀‐PEG conjugates indicates potential applications in areas such as temperature sensors and thermoresponsive materials.     

Synthesis and crystal structure of 2‐amino‐3‐hydroxypyridinium dioxido(pyridine‐2,6‐dicarboxylato‐κ3O2,N,O6)vanadate(V) and its conversion to nanostructured V2O5

2‐Amino‐3‐hydroxypyridinium dioxido(pyridine‐2,6‐dicarboxylato‐κ³O²,N,O⁶)vanadate(V), (C₅H₇N₂O)[V(C₇H₃NO₄)O₂] or [H(amino‐3‐OH‐py)][VO₂(dipic)], (I), was prepared by the reaction of VCl₃ with dipicolinic acid (dipicH₂) and 2‐amino‐3‐hydroxypyridine (amino‐3‐OH‐py) in water. The compound was characterized by elemental analysis, IR spectroscopy and X‐ray structure analysis, and consists of an anionic [VO₂(dipic)]⁻ complex and an H(amino‐3‐OH‐py)⁺ counter‐cation. The V^V ion is five‐coordinated by one O,N,O′‐tridentate dipic dianionic ligand and by two oxide ligands. Thermal decomposition of (I) in the presence of polyethylene glycol led to the formation of nanoparticles of V₂O₅. Powder X‐ray diffraction (PXRD) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of the synthesized powder.     

Influence of the Organic Species and Oxoanion in the Synthesis of two Uranyl Sulfate Hydrates, (H3O)2[(UO2)2(SO4)3­(H2O)]·7H2O and (H3O)2[(UO2)2(SO4)3(H2O)]·4H2O,and a Uranyl Selenate‐Selenite [C5H6N][(UO2)(SeO4)(HSeO3)]

Two uranyl sulfate hydrates, (H₃O)₂[(UO₂)₂(SO₄)₃(H₂O)] · 7H₂O (NDUS) and (H₃O)₂[(UO₂)₂(SO₄)₃(H₂O)] · 4H₂O (NDUS1), and one uranyl selenate‐selenite [C₅H₆N][(UO₂)(SeO₄)(HSeO₃)] (NDUSe), were obtained and their crystal structures solved. NDUS and NDUSe result from reactions in highly acidic media in the presence of L ‐cystine at 373 K. NDUS crystallized in a closed vial at 278 K after 5 days and NDUSe in an open beaker at 278 K after 2 weeks. NDUS1 was synthesized from aqueous solution at room temperature over the course of a month. NDUS, NDUS1, and NDUSe crystallize in the monoclinic space group P2₁/n, a = 15.0249(4) Å,b = 9.9320(2) Å, c = 15.6518(4) Å, β = 112.778(1)°, V = 2153.52(9) ų,Z = 4, the tetragonal space group P4₃2₁2, a = 10.6111(2) Å,c = 31.644(1) Å, V = 3563.0(2) ų, Z = 8, and in the monoclinic space group P2₁/n, a = 8.993(3) Å, b = 13.399(5) Å, c = 10.640(4) Å,β = 108.230(4)°, V = 1217.7(8) ų, Z = 4, respectively.The structural units of NDUS and NDUS1 are two‐dimensional uranyl sulfate sheets with a U/S ratio of 2/3. The structural unit of NDUSe is a two‐dimensional uranyl selenate‐selenite sheets with a U/Se ratio of 1/2. In‐situ reaction of the L ‐cystine ligands gives two distinct products for the different acids used here. Where sulfuric acid is used, only H₃O⁺ cations are located in the interlayer space, where they balance the charge of the sheets, whereas where selenic acid is used, interlayer C₅H₆N⁺ cations result from the cyclization of the carboxyl groups of L ‐cystine, balancing the charge of the sheets.     

Weak C—H...O and C—H...π hydrogen bonds and π–π stacking interactions in a series of four N′‐[(E)‐(aryl)methylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazides

Oxazolidin‐2‐ones are widely used as protective groups for 1,2‐amino alcohols and chiral derivatives are employed as chiral auxiliaries. The crystal structures of four differently substituted oxazolidinecarbohydrazides, namely N′‐[(E)‐benzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂N₃O₃, (I), N′‐[(E)‐2‐chlorobenzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂ClN₃O₃, (II), (4S)‐N′‐[(E)‐4‐chlorobenzylidene]‐N‐methyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₂H₁₂ClN₃O₃, (III), and (4S)‐N′‐[(E)‐2,6‐dichlorobenzylidene]‐N,3‐dimethyl‐2‐oxo‐1,3‐oxazolidine‐4‐carbohydrazide, C₁₃H₁₃Cl₂N₃O₃, (IV), show that an unexpected mild‐condition racemization from the chiral starting materials has occurred in (I) and (II). In the extended structures, the centrosymmetric phases, which each crystallize with two molecules (A and B) in the asymmetric unit, form A+B dimers linked by pairs of N—H...O hydrogen bonds, albeit with different O‐atom acceptors. One dimer is composed of one molecule with an S configuration for its stereogenic centre and the other with an R configuration, and possesses approximate local inversion symmetry. The other dimer consists of either R,R or S,S pairs and possesses approximate local twofold symmetry. In the chiral structure, N—H...O hydrogen bonds link the molecules into C(5) chains, with adjacent molecules related by a 2₁ screw axis. A wide variety of weak interactions, including C—H...O, C—H...Cl, C—H...π and π–π stacking interactions, occur in these structures, but there is little conformity between them.     

Kristallstruktur von Natrium‐Dihydrogencyamelurat‐Tetrahydrat Na[H2(C6N7)O3] · 4 H2O

Crystal Structure of Sodium Dihydrogencyamelurate Tetrahydrate Na[H₂(C₆N₇)O₃] · 4 H₂O Sodium dihydrogencyamelurate‐tetrahydrate Na[H₂(C₆N₇)O₃]·4 H₂O was obtained by neutralisation of an aqueous solution, previously prepared by hydrolysis of the polymer melon with sodium hydroxide. The crystal structure was solved by single‐crystal X‐ray diffraction ( a = 6.6345(13), b = 8.7107(17), c = 11.632(2) Å, α = 68.96(3), β = 87.57(3), γ = 68.24(3)°, V = 579.5(2) ų, Z = 2, R1 = 0.0535, 2095 observed reflections, 230 parameters). Both hydrogen atoms of the dihydrogencyamelurate anion are directly bound to nitrogen atoms of the cyameluric nucleus, thus proving the preference of the keto‐tautomere in salts of cyameluric acid in the solid‐state. The compound forms a layer‐like structure with an extensive hydrogen bonding network.     

Adsorption of gas mixtures on heterogeneous solid surfaces: I. Extension of Tóth isotherm on adsorption from gas mixtures

Summary It was proved that the partial adsorbed quantities can be calculated from the individual adsorption isotherms. This calculation can be carried out by equations which take into' account the energetical heterogeneity of the surface of adsorbent as well. Thus, the partial isotherms equations which can be applied are as followsV _A (p _A ,p _B ) =p _A /[b _a + (p _A +b _AB p _B ) ^m ] ^1/m andV _B (p _A ,p _B ) =p _B /[b _B + (p _B +b _BA p _A ) ^m ] ^1/m wherep _A andp _B are the partial equilibrium pressures, whileb _A ,b _B andm are constants which can be determined on the basis of the individual isotherms.

---

Zusammenfassung Es wurde nachgewiesen, daß die partialen Adsorbatmengen aus den individuellen Isothermen berechnet werden können. Die Berechnung kann mit Hilfe von Gleichungen durchgeführt werden, die auch die energetische Inhomogenität der adsorbierenden Oberfläche berücksichtigen. Benutzt werden die Gleichungen: V_A(p_A,p_B) = p_A/ [b_A + (PA + b_ABp_B)^m]^1/m und V_B(p_A,p_B) p_B/[b_B + (p_B + b_BAp_A)^m]^1/m , wop _A undp _B die Gleichgewichtspartialdrucke undb _A ,b _B undm die aus den individuellen Isothermen zu bestimmenden Konstanten darstellen.

     

A non‐oxo methanolate‐bridged divanadium(IV) complex with tris(2‐sulfanidylphenyl)phosphane ligands: synthesis,structural characterization and magnetic investigation

Vanadium chemistry is of interest due its biological relevance and medical applications. In particular, the interactions of high‐valent vanadium ions with sulfur‐containing biologically important molecules, such as cysteine and glutathione, might be related to the redox conversion of vanadium in ascidians, the function of amavadin (a vanadium‐containing anion) and the antidiabetic behaviour of vanadium compounds. A mechanistic understanding of these aspects is important. In an effort to investigate high‐valent vanadium–sulfur chemistry, we have synthesized and characterized the non‐oxo divanadium(IV) complex salt tetraphenylphosphonium tri‐μ‐<!?tlsb=‐0.11pt>methanolato‐κ⁶O:O‐bis({tris[2‐sulfanidyl‐3‐(trimethylsilyl)phenyl]phosphane‐κ⁴P,S,S′,S′′}vanadium(IV)) methanol disolvate, (C₂₄H₂₀P)[V^IV₂(μ‐OCH₃)₃(C₂₇H₃₆PS₃)₂]·2CH₃OH. Two V^IV metal centres are bridged by three methanolate ligands, giving a C2‐symmetric V₂(μ‐OMe)₃ core structure. Each V^IV centre adopts a monocapped trigonal antiprismatic geometry, with the P atom situated in the capping position and the three S atoms and three O atoms forming two triangular faces of the trigonal antiprism. The magnetic data indicate a paramagnetic nature of the salt, with an S = 1 spin state.     

Syntheses and Crystal Structures of BaAgTbS3, BaCuGdTe3, BaCuTbTe3, BaAgTbTe3, and CsAgUTe3

Five new quaternary chalcogenides of the 1113 family, namely BaAgTbS₃, BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃, were synthesized by the reactions of the elements at 1173–1273 K. For CsAgUTe₃ CsCl flux was used. Their crystal structures were determined by single‐crystal X‐ray diffraction studies. The sulfide BaAgTbS₃ crystallizes in the BaAgErS₃ structure type in the monoclinic space group C³,_2h‐C2/m, whereas the tellurides BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and CsAgUTe₃ crystallize in the KCuZrS₃ structure type in the orthorhombic space group D¹_,2⁷_,h‐Cmcm. The BaAgTbS₃ structure consists of edge‐sharing [TbS₆^9–] octahedra and [AgS₅^9–] trigonal pyramids. The connectivity of these polyhedra creates channels that are occupied by Ba atoms. The telluride structure features ²_∞[MLnTe₃^2–] layers for BaCuGdTe₃, BaCuTbTe₃, BaAgTbTe₃, and ²_∞[AgUTe₃^1–] layers for CsAgUTe₃. These layers comprise [MTe₄] tetrahedra and [LnTe₆] or [UTe₆] octahedra. Ba or Cs atoms separate these layers. As there are no short Q ··· Q (Q = S or Te) interactions these compounds achieve charge balance as Ba²⁺M⁺Ln³⁺(Q^2–)₃ (Q = S and Te) and Cs⁺Ag⁺U⁴⁺(Te^2–)₃.     

Investigation of Copper Halide:Hydrothermal Syntheses and Characterization of CuBr2(C12H8N2) and Cu3Br3(C12H8N2)2

The reaction of CuBr₂ with 1,10‐phen‐H₂O (1,10‐phen = 1,10‐phenanthroline) gave two compounds: CuBr₂(C₁₂H₈N₂) and Cu₃Br₃(C₁₂H₈N₂)₂. Their structures have been characterized by single‐crystal X‐ray diffraction analysis, elemental analyses, thermogravimetric analyses (TGA) and measurement of variable temperature magnetic susceptibility. Crystal data for CuBr₂(C₁₂‐H₈N₂): monoclinic, space group P2₁/n, a = 0.9977(3) nm, b = 0.65138(14) nm, c = 1.8207(4) nm, β = 91.624(18)°, V = 1.1828(5) nm³, Z = 2. Crystal data for Cu₃Br₃(C₁₂H₈N₂)₂: monoclinic, space group C2/c, a = 1.00167(11) nm, b = 1.4523(4) nm, c = 1.6295(3) nm, β = 94.386(14)°, V = 2.3635(8) nm³, Z = 3.     

Photoinduced hydrogen evolution with bisviologen-linked ruthenium(II) complexes and hydrogenase

Bisviologen-linked ruthenium(II) complexes with different methylene chain length between ruthenium complex and viologen, Ru(bpy)₂(dcbpy)C_mV_AC_nV_B(m=2, n=3; m=3, n=4), were synthesized and characterized. From luminescence spectra, the photoexcited state of Ru(bpy)₂(dcbpy) moiety is oxidatively quenched by the bound viologen, and an intramolecular electron transfer occurs. Luminescence lifetime measurements show that the electron transfers from the photoexcited state of ruthenium(II) complex moiety to the bound bisviologen more rapidly than that of monoviologen-linked ruthenium(II) complexes. Ru(bpy)₂(dcbpy)C_mV_AC_nV_B were applied to the photoinduced hydrogen evolution in the system containing nicotinamide-adenine dinucleotide phosphate (reduced form, NADPH), Ru(bpy)₂(dcbpy)C_mV_AC_nV_B and hydrogenase under steady state irradiation. In the case of Ru(bpy)₂(dcbpy)C₃V_AC₄V_B, the efficient photoinduced hydrogen evolution was observed.     

9(R)‐[6(R)‐Hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]hypoxanthine–water (4/3), a nucleoside analogue

The title compound, 9(R)‐[6(R)‐hydroxy­methyl‐1‐oxa‐4‐thia­cyclo­hexan‐2‐yl]‐1,9‐di­hydro‐6H‐purin‐6‐one–water (4/3), C₁₀H₁₂N₄O₃S·0.75H₂O, crystallizes in the triclinic space group P1 with four mol­ecules in the asymmetric unit and 0.75 waters of hydration per mol­ecule. The structure was refined to an R value of 0.072 for 3382 observed reflections. The four crystallographically independent mol­ecules are designated A, B, C and D. All four oxa­thia­ne rings adopt the chair conformation and the purine bases are in an anti orientation with respect to the sugar moieties. Molecules A and D and mol­ecules C and B are base paired by a single hydrogen bond of the type N—H?N. These base pairs are again hydrogen bonded to their translated pairs in the direction of a cell diagonal.     

Ag3.5Bi7.5S13, a new member (N = 8) of the homologous series [Bi2S3]2·[AgBiS2](N−1)/2

The silver bismuth trideca­sulfide Ag_3.5Bi_7.5S₁₃ crystallizes in the monoclinic space group C2/m. Its structure is built up of two alternating kinds of layered modules parallel to (001). In the module denoted A, octa­hedra around the metal positions (M = Ag/Bi, M2 and an S atom on 2/m, other atoms on m) alternate with paired monocapped trigonal prisms around Bi. The NaCl‐type module B is composed of parallel eight‐membered chains of edge‐sharing octa­hedra running dia­gonally across it. Ag_3.5Bi_7.5S₁₃ is the member with N = 8 of the pavonite homologous series ^NP of ternary compounds with the general formula [Bi₂S₃]₂·[AgBiS₂]_(N−1)/2.