Zur Kenntnis der Kristallstruktur von Melem C6N7(NH2)3

On the Crystal Structure of Melem C₆N₇(NH₂)₃ Single crystals of melem ( 1 ) were grown from both DMSO‐solutions and the gas phase. The structure of melem ( 1 ) was solved by single‐crystal X‐ray diffraction (P2₁/c, Z = 4, a = 741.66(15), b = 862.28(17), c = 1335.9(3) pm, β = 99.91(3)° R1 = 0.037 for 1098 reflections). The structure determination by X‐ray powder diffraction, which has been previously conducted, is in agreement with our data. The increased quality of the structural information allows for a more detailed understanding of the hydrogen bonding network.     

Synthesis and Structural Analysis of ϵ‐Fe2O3

Powder material of ?‐Fe₂O₃ was obtained by thermal decomposition of the clay mineral nontronite and subsequent isolation of the ferric oxide by leaching the silicate phases. Additionally, crystals of ?‐Fe₂O₃ were grown as precipitates by internal oxidation of a Pd₉₆Fe₄ alloy. Analysis of the precipitate crystals by electron diffraction yields an orthorhombic crystal system and space group Pna2₁ ab initio. X‐ray diffraction data of the powder containing small amounts of Al substituting Fe were refined by the Rietveld method. The refinement yields lattice parameters a = 507.15 pm, b = 873.59 pm and c = 941.78 pm, and atom positions. ?‐Fe₂O₃ is isostructural with κ‐Al₂O₃, AlFeO₃, and GaFeO₃ having an anion stacking sequence /ABAC/, and 1/4 of the cations in tetrahedral co‐ordination. Some strongly distorted FeO₆ octahedrons with one large Fe‐O distance, which may be considered as a 5+1 co‐ordination, appear to be characteristic for ?‐Fe₂O₃. The structure shows elements known from silicates and oxyhydroxides of iron, respectively.     

Synthesis and Characterization of the Germanium Sulfonate Ge(CH3SO3)2 – a 3D Coordination Network Solid

The reaction of germanium(II)‐bis(2‐methoxyphenyl)methoxide with methanesulfonic acid provides the germanium(II) sulfonate Ge(CH₃SO₃)₂ ( 1 ), which was characterized by X‐ray diffraction, elemental analysis, NMR spectroscopy, and IR spectroscopy. The decomposition process of 1 was investigated by thermal gravimetric analysis (TGA) and temperature‐dependent X‐ray powder diffraction (PXRD) and both are consistent with the formation of GeO₂ as major final product. Single crystal X‐ray diffraction at 110 K revealed the chiral tetragonal space group P4₁2₁2 and formation of a three‐dimensional (3D) coordination network solid. The 3D network is composed of interconnected twenty four‐membered rings comprising bridging methanesulfonate groups, which link the germanium atoms.     

Chirality and Order in Binary Molecular Crystals of Inert Cobalt(III) Complexes

Starting from the enantiomerically pure and racemic chiral Lewis bases 1‐phenylethylamine and 1‐(1‐naphthyl)ethylamine inert cobalt(III) complexes of the general composition Co(Hdmg)₂(lig)X (Hdmg = dimethylglyoximate; lig = Lewis base; X = CN, NCO, NO₂) were synthesized and characterized by single crystal X‐ray diffraction. The enantiopure complexes were used as building blocks for the synthesis of binary crystals. Solid solutions resulted from cocrystallizing isomorphous compounds of equal chirality whereas complexes of opposite chirality formed well‐ordered heterochiral solids with efficient packing. Two binary crystals of the latter type could be studied by X‐ray diffraction: Cocrystallization of two isomorphous phenylethylamine derivatives gave a quasiracemic solid. Starting from two non‐isomorphous naphthylethylamine complexes of opposite chirality cocrystals with an unexpected composition were obtained: Their asymmetric unit comprises four independent complex molecules in a 3:1 ratio between the constituents.     

X‐Ray and Electron Diffraction Study of Poly(p‐dioxanone)

Summary: Solution‐grown lamellar crystals of poly(p‐dioxanone) (PPDX) have been crystallized isothermally from butane‐1,4‐diol at 100 °C. The crystal structure of PPDX has been determined by interpretation of X‐ray fiber diagrams of PPDX fibers and electron diffraction diagrams of lozenge‐shaped chain‐folder lamellar crystals. The unit cell of PPDX is orthorhombic with space group P2₁2₁2₁ and parameters: a = 0.970 nm, b = 0.742 nm, and c (chain axis) = 0.682 nm. There are two chains per unit cell, which exist in an antiparallel arrangement.

Transmission electron micrograph of PPDX chain‐folded lamellar crystals obtained by isothermal crystallization and its electron diffraction diagram.     

Calcined Mg-Al Layered Double Hydroxide as a Heterogeneous Catalyst for the Synthesis of Urea Derivatives from Amines and CO2

The calcined Mg‐Al layered double hydroxides (LDHs) with a Mg/Al molar ratio of 3:1 were synthesized and characterized thoroughly by X‐ray diffraction (XRD), temperature‐programmed desorption (TPD) of CO₂, and thermogravimetric analysis (TGA). Thus the calcined Mg‐Al LDHs were used as catalyst for the catalytic synthesis of disubstituted ureas from amines and CO₂. The effects of reaction time, reaction temperature, pressure, solvent and calcined temperature on activity have been investigated. The results indicated that aliphatic amines, cyclohexylamine and benzylamine can be converted to the corresponding ureas selectively over the calcined Mg‐Al LDHs catalysts with N‐methyl‐2‐pyrrolidone (NMP) as solvent without using any dehydrating regent. The catalyst can be recycled several times with only slight loss of activity.     

Synthesis and characterization of aluminum complexes based on amino‐benzotriazole phenoxide ligand: luminescent properties and catalysis for ring‐opening polymerization

Aluminum complexes coordinated by a ^C1DEABTP ligand (^C1DEABTP‐H = 2‐(2H‐benzotriazol‐2‐yl)‐6‐((diethylamino)methyl)‐4‐methylphenol) were synthesized and structurally characterized. The formation of Al complexes is dependent on the stoichiometry of AlMe₃ to ^C1DEABTP ligand ratio. The reaction of ^C1DEABTP‐H with AlMe₃ (1.0 molar equiv.) in hexane produced mono‐adduct aluminum complex [(^C1DEABTP)AlMe₂] (1), but treatment of ^C1DEABTP‐H with 2.0 molar equiv. of AlMe₃ afforded mixtures of [(^C1DEABTP)Al₂Me₅] (2) and [(^C1DEABTP)Al₃Me₈] (3). The penta‐coordinated bis‐adduct aluminum complex [(^C1DEABTP)₂AlMe] (4) was synthesized through the reaction of AlMe₃ with ^C1DEABTP‐H (2.0 molar equiv.) in hexane. Tri‐adduct Al complex [(^C1DEABTP)₃Al] (5) resulted from treatment of AlMe₃ with ^C1DEABTP‐H (3.0 equiv.); the Al center is hexa‐coordinated with three N,O‐bidentate ^C1DEABTP ligands. X‐ray diffraction of single crystals indicates that the bonding modes of the ^C1DEABTP ligands in complexes 2–3 are greatly affected when excess AlMe₃ is coordinated. The optical properties and catalysis for lactone polymerizations of ^C1DEABTP coordinated to Al complexes were tested. Tri‐adduct Al complex 5 produced an intense green fluorescence in both solution and the solid state. Complex 4 is an active catalyst for the ring‐opening polymerization of ε‐caprolactone (ε‐CL) and L‐lactide (L‐LA) in the presence of 9‐anthracenemethanol (9‐AnOH). In ε‐CL polymerization, Al complex 4 catalyzes efficiently in both a 'controlled' and 'immortal' manner, giving polymers with the expected molecular weights and narrow polydispersity indexes. Copyright © 2012 John Wiley & Sons, Ltd.     

Chemical synthesis of biodegradable aliphatic polyesters and polycarbonates catalyzed by novel versatile aluminum metal complexes bearing salen ligands

Two novel aluminum metal complexes ( 2 and 3 ) bearing salen ligands were in situ prepared from trimethyl aluminum (AlMe₃), methanol, and (R,R)‐N,N′‐bis(salicylidene)‐1,2‐diaminocyclohexane with original synthetic strategies, and a preliminarily resoluted (R,R)‐1,2‐diaminocyclohexane was applied as a synthetic precursor. By means of Fourier transform infrared spectrometry, NMR spectrometry, mass spectrometry, and single‐crystal X‐ray diffractometry, 2 and 3 were revealed to be distinct molecular structures with corresponding yields of 85 and 10%, respectively. Further studies via ²⁷Al NMR techniques and single‐crystal X‐ray diffraction indicated that dimeric metal complex 3 appeared in the six‐coordinated state, whereas there was a dynamic equilibrium transition between the five‐ and six‐coordinated states for metal complex 2 in a CDCl₃ solution. The more stable dimeric metal complex ( 3 ) exhibited two inequivalent aluminum metal centers coordinated to nitrogen atoms attributed to two different salen ligands, and this was different from the reported salen aluminum complex structures. Furthermore, 2 and 3 were employed as candidate catalysts for the ring‐opening polymerization (ROP) of some important biodegradable aliphatic polyesters and polycarbonates, including poly(?‐caprolactone) (PCL), poly(δ‐valerolactone), poly(trimethylene carbonate), and poly(2,2‐dimethyl trimethylene carbonate). The synthetic results indicated that both metal complexes efficiently catalyzed ROP at 100 °C in an anisole solution, and 3 showed much better controlled characteristics of ROP than 2 . Very narrow molecular weight distributions close to 1.21 for PCL were detected with 3 as the ROP catalyst. In addition, a catalytic mechanism study confirmed that ROP catalyzed by these metal complexes was in good agreement with the commonly accepted coordination polymerization reported for aluminum triiso [Al(OⁱPr)₃] and stannous octanoate [Sn(Oct)₂]. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 373–384, 2005     

Monoclinic structure and nonstoichiometry of `KAlSiO4‐O1'

Crystals of KAlSiO₄‐O1 (potassium aluminium silicate) were synthesized using a flux method and analysed utilizing single‐crystal X‐ray diffraction and electron microprobe analysis. Both methods confirm that the crystals are nonstoichiometric according to K_1−xAl_1−xSi_1+xO₄ with x = 0.04 (1). KAlSiO₄‐O1 is closely related to the stuffed derivatives of tridymite, although the topology of the Si/Al‐ordered framework is different. Six‐membered rings of UUDDUD and UUUDDD (U = up and D = down; ratio 2:1) configurations are present in layers parallel to the ab plane. In contrast, the framework of tridymite exhibits UDUDUD rings. The crystals are affected by inversion, pseudo‐orthorhombic and pseudo‐hexagonal twinning.     

Synthesis,Crystal Structure,and Properties of the 3D Porous Framework [Zn(INAIP)]·DMA·H2O

A new three‐dimensional (3D) porous framework [Zn(INAIP)] · DMA · H₂O ( 1 ) [INAIP = 5‐(isonicotinamido)isophthalate, DMA = N,N′‐dimethylacetamide] was synthesized by solvothermal methods and characterized by single‐crystal and powder X‐ray diffraction, as well as thermogravimetric analysis. The results of X‐ray diffraction analyses revealed that complex 1 has an unusual 3D architecture with the (3,6)‐connected rutile ( rtl ) topology. The adsorption behavior shows that compound 1 exhibits selective adsorptions of CO₂ over N₂ after the removal of the solvent molecules within the pores.     

Thermodynamic Phase Transition Through Crystal‐to‐Crystal Process of Photochromic 1,2‐Bis(5‐phenyl‐2‐propyl‐3‐thienyl)perfluorocyclopentene

A photochromic diarylethene, 1,2‐bis(5‐phenyl‐2‐propyl‐3‐thienyl)perfluorocyclopentene ( 1a ), was found to have two polymorphic crystal forms, α‐ and β‐crystals. From X‐ray crystallographic analysis, the space groups of α‐ and β‐crystals were determined to be P2₁/c and C2/c, respectively. The difference between two crystal forms is ascribed to the orientation of two of four molecules in the unit cell. The thermodynamic phase transition from α‐ to β‐forms occurred via a crystal‐to‐crystal process, as confirmed by differential scanning calorimetry measurements, optical microscopic observations in the reflection mode and under crossed Nicols, and powder X‐ray diffraction measurements. The movement of the molecules in the crystal was evaluated by analyzing the change of face indices before and after the phase transition.     

Synthesis,Crystal Structure,and Reactivity of Na5[CuO2](OH)2

Na₅[CuO₂](OH)₂ has been obtained as orange single crystals from mixtures of NaOH, Na₂O and Cu₂O in sealed Ag containers. The crystal structure has been refined from X‐ray diffraction data (IPDS data, Pnma, Z = 4, a = 607.4(1) pm, b = 891.2(1) pm, c = 1201.0(2) pm, R₁ = 0.03). The characteristic unit is the bent [CuO₂]^3– complex (∠(O–Cu–O) = 170°). The reactivity of Na₅[CuO₂](OH)₂ has been studied by DSC and in situ X‐ray diffraction techniques. IR spectroscopy has been used for further characterization. The Madelung Part of the Lattice Energy (MAPLE) has been calculated as well.     

Synthesis,Crystal Structure and Lithium Motion of Li8SeN2 and Li8TeN2

The compounds Li₈EN₂ with E = Se, Te were obtained in form of orange microcrystalline powders from reactions of Li₂E with Li₃N. Single crystal growth of Li₈SeN₂ additionally succeeded from excess lithium. The crystal structures were refined using single‐crystal X‐ray diffraction as well as X‐ray and neutron powder diffraction data (I4₁md, No. 109, Z = 4, Se: a = 7.048(1) Å, c = 9.995(1) Å, Te: a = 7.217(1) Å, c = 10.284(1) Å). Both compounds crystallize as isotypes with an anionic substructure motif known from cubic Laves phases and lithium distributed over four crystallographic sites in the void space of the anionic framework. Neutron powder diffraction pattern recorded in the temperature range from 3 K to 300 K and X‐ray diffraction patterns using synchrotron radiation taken from 300 K to 1000 K reveal the structural stability of both compounds in the studied temperature range until decomposition. Motional processes of lithium atoms in the title compounds were revealed by temperature dependent NMR spectroscopic investigations. Those are indicated by significant changes of the ⁷Li NMR signals. Lithium motion starts for Li₈SeN₂ above 150 K whereas it is already present in Li₈TeN₂ at this temperature. Quantum mechanical calculations of NMR spectroscopic parameters reveal clearly different environments of the lithium atoms determined by the electric field gradient, which are sensitive to the anisotropy of charge distribution at the nuclear sites. With respect to an increasing coordination number according to 2 + 1, 3, 3 + 1, and 4 for Li(3), Li(4), Li(2), and Li(1), respectively, the values of the electric field gradients decrease. Different environments of lithium predicted by quantum mechanical calculations are confirmed by ⁷Li NMR frequency sweep experiments at low temperatures.     

The Hydrothermal Synthesis of Sulfate Cancrinite (SO4‐CAN): Relations between Si‐Al Sources and Crystal Quality

Sulfate cancrinite (SO₄‐CAN) Na₈[AlSiO₄]₆(SO₄)(H₂O)_n (2.6 < n < 3.2) was synthesized under hydrothermal conditions at 200 °C and 48 hours. Three different Si‐Al sources were inserted: (a) kaolinite (K), (b) a gel of sodium‐waterglass and sodium aluminate (G), and (c) an oxide mixture of cristobalite and corundum (CK). The products were characterized by X‐ray powder diffraction (XRD), ²⁹Si and ²⁷Al MAS NMR spectroscopy, scanning electron microscopy (SEM), energy dispersive X‐ray spectroscopy (EDXS) and BET surface area analysis as well as simultaneous thermoanalysis (TG‐DTA). Mostly nanocrystals of platelet habit and dimensions smaller than 100 nm (beside a very few larger crystals) were observed from K. In contrast the gel (G) yielded to cancrinites with typical rod‐like morphology and dimensions of 100 × 500 nm. Large prismatic cancrinites up to 5 μm width and 10 μm length were observed from the oxide mixture CK. Furthermore the transition kinetics of the cancrinites into nosean was investigated at a temperature of 1000 °C under open conditions. This process was already complete after 1 hour for the nanocrystals from K but needed 10 hours for the nanocrystals from G and the microcrystals from CK. The relations between the individual Si‐Al source and the crystal properties like size, habit, and thermal transition kinetics were discussed.     

Synthesis and Modulated Crystal Structure of KBaNbS4

Single crystals of KBaNbS₄ have been prepared by the reaction of Nb with an in situ formed melt of K₂S₃, BaS, and S at 500 °C. Satellite reflections observed in X‐ray diffraction experiments of these crystals indicate the presence of a one‐dimensional lattice distortion. The modulated structure has been solved and refined from X‐ray data using the superspace group approach. KBaNbS₄ can be described in the (3 + 1)‐dimensional superspace group Pnma(α00)0s0 with lattice parameters a = 9.187(1), b = 7.001(1), and c = 12.494(1) Å and a modulation vector q = (0, 0.629(1), 0). In the structure the NbS₄ tetrahedra are stacked along the a axis and show a slight tilting against each other. The K⁺ and Ba²⁺ ions follow this tilting, both are slightly shifted from their positions in the average structure. The modulation does not lead to a significant change in the coordination spheres of the metal atoms. The small effects of the modulation correspond to the relatively weak intensities of the satellite reflections. Results of temperature dependent X‐ray investigations indicate that K⁺ librates at higher temperatures and the surrounding S^2? anions follow this motion. With decreasing temperature the libration of K⁺ is reduced and the coordination geometry freezes under formation of an incommensurate modulation. The heavier Ba and Nb atoms are also affected by positional modulation of the substructure and accommodate to their environment.     

Magnesium diiodide,MgI2

Single crystals of magnesium diiodide have been grown and the structure solved for the first time from single‐crystal X‐ray diffraction data. This study confirms that MgI₂ is isostructural with CdI₂ (C6 or 2H structure type). The space group is with the Mg atom on a site with 3m symmetry (Wyckoff site 1a) and the I atom on a site with m symmetry (Wyckoff site 2d). Trends in the 2H structures of dihalides are discussed briefly.     

Organotin Dyes: Synthesis and Structural Characterization of Dibutyltin and Dimethyltin Complexes with 2, 2′‐Dihydroxyazobenzene

The preparation and structures of 2, 2′‐dihydroxyazobenzenato‐dibutyl‐tin [Bu₂SnL] and 2, 2′‐dihydroxyazobenzenato‐dimethyl‐tin [Me₂SnL] are described. The complexes were characterized by IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and UV/VIS spectra. The crystal structures were determined by X‐ray diffraction on single crystals. [Bu₂SnL]: monoclinic, space group P2₁/c, cell constants at 208 K: a = 860.73(5), b = 973, 51(18), c = 2340.0(3) pm, β = 93.615(11)°; R₁ = 0.0546. [Me₂SnL]: orthorhombic, space group Pbcn, cell constants at 208 K: a = 1914.6(4), b = 1041.3(3), c = 1323.27(14) pm; R₁ = 0.0529.     

[Te8][NbOCl4]2 containing an infinite chain‐like {[Te–Te–Te–(Te5)]2+}n polycation

The title compound, [Te₈][NbOCl₄]₂, was obtained as translucent black crystals by reaction of elemental tellurium, niobium(V) chloride and niobium(V) oxychloride in the ionic liquid BMImCl (BMImCl is 1‐butyl‐3‐methylimidazolium chloride). The synthesis was performed in argon‐filled glass ampoules. According to X‐ray structure analysis based on single crystals, the title compound crystallizes with triclinic lattice symmetry and consists of infinite {[Te₈]²⁺}_n cations associated with pyramidal [NbOCl₄]⁻ anions. The novel catena‐octatellurium(2+) cation is composed of Te₅ rings that are linked via Te₃ units [Te—Te = 2.6455 (18)–2.8164 (19) Å]. The composition and purity of [Te₈][NbOCl₄]₂ were further confirmed by energy‐dispersive X‐ray diffraction (EDX) analysis.     

The high‐temperature modification of zinc catena‐polyphosphate, β‐Zn(PO3)2

Single crystals of the high‐temperature modification of zinc catena‐polyphosphate, β‐Zn(PO₃)₂, were grown from a melt and quenched from 1093 K to room temperature. The structure was solved from single‐crystal X‐ray diffraction data and is built of corrugated (PO₃)_∞ polyphosphate chains, which extend along the c direction with an eight‐tetrahedra repeat. Slightly distorted [ZnO₄] tetrahedra link the polyphos­phate chains into a three‐dimensional network.     

Three New Lanthanide Coordination Polymers Built from H2bpdc Ligands: Syntheses,Structures, and Properties

Three new lanthanide‐organic coordination polymers, {[Ln₂(bpdc)₂(H₂O)₆(NO₃)] · NO₃} [Ln = La ( 1 ), Ce ( 2 ), Pr ( 3 )] (H₂bpdc = 2, 2′‐bipyridine‐6, 6′‐dicarboxylic acid) were synthesized under hydrothermal conditions and structurally characterized by elemental analysis, IR spectroscopy as well as single‐crystal and powder X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that compounds 1 – 3 are isostructural, composed of two dimensional honeycomb network linked by bpdc ligands. The magnetic property of compound 3 was investigated.