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Volume changes associated with the (de)lithiation of a nanostructured Ni3Sn2 coated nickel inverse opal scaffold anode create mismatch stresses and strains between the Ni3Sn2 anode material and its mechanically supporting Ni scaffold. Using in operando synchrotron x-ray diffraction measurements, elastic strains in the Ni scaffold are determined during cyclic (dis)charging of the Ni3Sn2 anode. These strains are characterized using both the center position of the Ni diffraction peaks, to quantify the average strain, and the peak breadth, which describes the distribution of strain in the measured volume. Upon lithiation (half-cell discharging) or delithiation (half-cell charging), compressive strains and peak breadth linearly increase or decrease, respectively, with charge. The evolution of the average strains and peak breadths suggests that some irreversible plastic deformation and/or delamination occurs during cycling, which can result in capacity fade in the anode. The strain behavior associated with cycling of the Ni3Sn2 anode is similar to that observed in recent studies on a Ni inverse-opal supported amorphous Si anode and demonstrates that the (de)lithiation-induced deformation and damage mechanisms are likely equivalent in both anodes, even though the magnitude of mismatch strain in the Ni3Sn2 is lower due to the lower (de)lithiation-induced contraction/expansion.

Ionic liquids (ILs) have many advantageous properties exploited in an increasing number of applications. Crucial to their continued and expanded use is the fine-tuning of IL structures to refine their capability profiles. Organic chemistry can play an important role in providing ILs with more sophisticated properties. In this communication, we provide relevant examples of the use of organic chemistry in the planning and delivery of novel structures and improved capabilities. Here we present three novel ILs characterized by X-ray crystallography resulting from partnering known anions, tetrafluoroborate (BF4−), bis (trifluoromethane) sulfonimide (TFSI−), and bromide (Br−) with novel cations based on three main structural types. The crystallographic analyses reported here highlight intermolecular and supramolecular features particularly the role of van der Waals interactions.

Herein, we describe the development of a novel dual air-bearing fixed-χ diffractometer for beamline I19 at Diamond Light Source. The diffractometer is designed to facilitate the rapid data collections possible with a Dectris Pilatus 2M pixel-array photon-counting detector, while allowing remote operation in conjunction with a robotic sample changer. The sphere-of-confusion is made as small as practicably possible, through the use of air-bearings for both the ω and φ axes. The design and construction of the new instrument is described in detail and an accompanying paper by Johnson et al. (also in this issue) will provide a user perspective of its operation.

The TiCl4 induced anomerization of selenium glycosides of galacturonic acid derivatives is reported. The reaction was successful for galacturonic acid when various alkyl, alkenyl, alkynyl, saccharide, steroid, and lipid groups were attached to the anomeric Se atom. An increased amount of TiCl4 and/or higher temperature were needed to ensure completion of the reaction in some cases. Yields were higher for reactions carried out at higher dilution. The reaction was applied to the synthesis of Se-based mimics of the potent immunostimulant alpha-GalCer (KRN7000). The research was supported by the Irish Research Council (PhD Scholarship to A.McD.) and NUI Galway (College of Science PhD scholarship to A.McD.). This publication has also emanated in part from research supported by Science Foundation Ireland (SFI, Grant Number 12/IA/1398) and is cofunded under the European Regional Development Fund under Grant Number 14/SP/2710. peer-reviewed 2017-01-22

Substituted semicarbazones/thiosemicarbazones and their copper complexes have been prepared and several single crystal structures examined. The copper complexes of these semicarbazone/thiosemicarbazones were prepared and several crystal structures examined. The single crystal X-ray structure of the pyridyl-substituted semicarbazone showed two types of copper complexes, a monomer and a dimer. We also found that the p-nitrophenyl semicarbazone formed a conventional 'magic lantern' acetate-bridged dimer. Electron Paramagnetic Resonance (EPR) of several of the copper complexes was consistent with the results of single crystal X-ray crystallography. The EPR spectra of the p-nitrophenyl semicarbazone copper complex in dimethylsulfoxide (DMSO) showed the presence of two species, confirming the structural information. Since thiosemicarbazones and semicarbazones have been reported to exhibit anticancer activity, we examined the anticancer activity of several of the derivatives reported in the present study and interestingly only the thiosemicarbazone showed activity while the semicarbazones were not active indicating that introduction of sulphur atom alters the biological profile of these thiosemicarbazones.

Chemical analysis of an Indonesian sponge sample has provided three new 3-alkylpiperidine alkaloids, tetradehydrohaliclonacyclamine A, its mono-N-oxide derivative, and a 2-epi isomer. The absolute structure of tetradehydrohaliclonacyclamine A has been established by X-ray crystallography from anomalous dispersion effects using Cu radiation, which determined that the absolute configuration is 2S, 3S, 7S, 9S while an HPLC study revealed that the alkaloid is enantiomerically pure.

Chain silicate glass ceramics based on K-fluorrichterite (KNa-CaMg 5 Si 8 O 22 F 2 , KFR) have potential for use in restorative dentistry and biomedical applications because they may be cast to shape and, when cerammed, have high biaxial flexural strength and fracture toughness. Excess CaO in canasite-based chain silicate compositions is known to enhance their bioactivity. Therefore, two new glass ceramic compositions have been fabricated with 5 mol% CaF 2 (Glass A) and 5 mol% CaO (Glass B) substituted for MgO in the KFR formula unit. The phase evolution of Glasses A and B was studied in detail using X-ray diffraction and transmission electron microscopy. In addition, their mechanical properties were assessed. For Glass A, the fracture toughness (FT = 2.66±0.02 MPa·m 1/2 ) and biaxial flexural strength (BFS = 227.3±24.5 MPa) were optimized for samples heat treated at 900°C for 4 h. In Glass B, however, the best FT (2.08±0.02 MPa·m 1/2 ) and BFS (217.4±4.4 MPa) were obtained at 950°C. In view of their excellent mechanical properties and castability, Glasses A and B are considered potential candidates for fabrication of custom medical devices in restorative dentistry and moderate load-bearing reconstructive bone surgery.

The crystal structure of the Cu(II) perchlorate complex of a functionalised bis(rnacrocycle) ligand, where the individual macrocycle units are of the cyclam type and adopt the trans-III configuration, is analysed in terms of its possible relationship to those of bis(macrocycle) complexes possessing anti-viral activity. To cite this article: P V Bernhardt et al., C. R. Chimie 8 (2005). (C) 2004 Academie des sciences. Published by Elsevier SAS. All rights reserved.

Canasite glass-ceramics were modified by either increasing the concentration of calcium in the glass, or by the addition of P2O5. Samples of these novel materials were placed in simulated body fluid (SBF), along with a control material (commercial canasite), for periods ranging from 12 h to 28 days. After immersion, surface analysis was performed using thin film X-ray diffraction, Fourier transform infrared reflection spectroscopy, and scanning electron microscopy equipped with energy dispersive X-ray detectors. The concentrations of sodium, potassium, calcium, silicon, and phosphorus in the SBF solution were measured using inductively coupled plasma emission spectroscopy. No apatite was detected on the surface of commercial canasite, even after 28 days of immersion in SBF. A crystalline apatite layer was formed on the surface of a P2O5-containing canasite after 5 days, and after 3 days for calcium-enriched canasite. Ion release data suggested that the mechanism for apatite deposition was different for P2O5 and non-P2O5-containing glass-ceramics.

Escherichia coli riboflavin synthase crystallizes at 22 C in the presence of 7-10percent by volume diglyme, 20-50 mM MgCl2 and pH 7.0. In this medium diffraction quality crystals are routinely obtained within 5 h and they are stable for 10 weeks. The crystals are orthogonal in space group P212121 with unit cell dimensions of a=52.4 A , b = 62.1 A, c = 218.8 A. A 97percent complete data set was collected at 2.1 A resolution.

The syntheses and characterisation of the new macrocyclic hexaamine trans-(5(S),7(S),12(R),14(R)-tetramethyl)-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (L-6) and its Co-III complex are reported. The X-ray crystal structural analyses of [CoL6]Cl-2(ClO4) [monoclinic, space group C2/c, a = 16.468(3) Angstrom, b = 9.7156(7) Angstrom, c = 15.070(3) Angstrom, beta = 119.431(8)degrees, Z = 4] and the closely related cis-diamino-substituted macrocyclic complex [CoL2](ClO4)(3) . 2H(2)O (L-2 = cis-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine) [orthorhombic, space group Pna2(1), a = 16.8220(8) Angstrom, b = 10.416(2) Angstrom, c = 14.219(3) Angstrom, Z = 4] reveal significant variations in the observed Co-N bond lengths and coordination geometries, which may be attributed to the trans or cis disposition of the pendent primary amines. The Co-III/II self-exchange electron transfer rate constants for these and other closely related hexaamines have been determined, and variations of some 2 orders of magnitude are found between pairs of trans and cis isomeric Co-III complexes.

Metastable but isolable mesoionic 1,3-oxazinium 4-olates 9d-f undergo ring opening to acylketenes 10 at or near room temperature. The ketenes undergo intramolecular criss-cross [2 + 2] cycloaddition to afford 3-azabicyclo[3.1.1]heptanetriones 12. The structure of 12d was established by X-ray crystallography.

Three-dimensional (3D) photonic crystals are one class of materials where epitaxy, and the resultant attractive electronic properties, would enable new functionalities for optoelectronic devices. Here we utilize self-assembled colloidal templates to fabricate epitaxially grown single crystal 3D mesostructured GaxIn1−xP (GaInP) semiconductor photonic crystals using hydride vapor phase epitaxy (HVPE). The epitaxial relationship between the 3D GaInP and the substrate is preserved during the growth through the complex geometry of the template as confirmed by X-ray diffraction (XRD) and high resolution transmission electron microscopy. XRD reciprocal space mapping of the 3D epitaxial layer further demonstrates the film to be nearly fully relaxed with a negligible strain gradient. Fourier transform infrared spectroscopy reflection measurement indicates the optical properties of the photonic crystal which agree with finite difference time domain simulations. This work extends the scope of the very few known meth...

The syntheses and characterization of the Co(III), Cr(III), and Ni(II) complexes of the pendant arm macrocyclic hexaamine cis-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine (cis-diammac) are reported and their spectroscopic and structural properties are compared with those of the known isomeric trans-diammac complexes with the aid of molecular mechanics and angular overlap model calculations. In contrast to the [M(trans-diammac)]n+ analogues, the [M(cis-diammac)]n+ complexes do not display short M-N bond lengths, nor are particularly high energy electronic maxima a feature. The [M(cis-diammac)]n+ complexes exhibit trigonally twisted geometries and more positive M(III/II) redox couples than their trans-diammac relatives. The X-ray crystal structure of [Cr(cis-diammac)](ClO4)3.2H2O is reported: C12H34Cl3CrN6O14, orthorhombic, space group Pc2(1)n, a = 10.455(4) angstrom, b = 14.262(4) angstrom, c = 16.905(7) angstrom, Z = 4.

The first row transition metal complexes [M(dipa)2]n+ (dipa = di-2-pyridylmethanamine, M = Fe(III), Fe(II), Co(III), Ni(II) and Cu(II)) have been synthesized in generally high yields. Stability constants for the labile Co(II), Ni(II), and Cu(II) complexes have been determined by potentiometric titrations and are as follows (log K1, log K2): 7.63 (1), 6.57 (1); 8.55 (1), 8.25 (1); and 8.89 (1), 7.94 (1). A rather large degree of steric strain within the complexes is evident from the X-ray crystal structures of rac-[Fe(dipa)2](ClO4)2.2H2O (monoclinic, P2(1)/n, a = 9.392 (3) angstrom, b = 16.749 (3) angstrom, c = 17.131 (14) angstrom, beta = 96.62 (5)-degrees, Z = 4) rac-[Co(dipa)2](ClO4)3 (orthorhombic, Pcca, a = 17.574 (5) angstrom, b = 8.568 (2) angstrom, c = 19.159 (3) angstrom, Z = 4), meso-[Ni(dipa)2](S2O6).4H2O (triclinic, P1BAR, a = 7.903 (3) angstrom, b = 9.810 (3) angstrom c = 10.900 (2) angstrom, alpha = 113.10 (3)-degrees, beta = 106.01 (3)-degrees, gamma = 96.93 (4)-degrees, Z = 1), and meso- [Cu(dipa)2] (ClO4)2 (monoclinic, P2(1)/n, a = 7.964 (3) angstrom, b = 10.1 54 (2) angstrom, c = 16.842 (4) angstrom, beta = 100.12 (4)-degrees, Z = 2). Molecular mechanics calculations indicate that the formation of rac-[Co(dipa)2]3+ in preference to the meso isomer is dominant, and this is in agreement with experimental results based on NMR spectra of equilibrated solutions. In the case of Cu(II), formation of the meso isomer is not selective, and this was confirmed by the successful Cu(II)-directed template condensation of the rac isomer with formaldehyde and nitroethane. Calculations also indicate that the rac isomer of the Ni(II) complex is more stable than the crystallized meso isomer.

A simple and efficient method for the determination of solution structures of weakly coupled binuclear copper(II) complexes is described. The technique involves the combination of molecular mechanics and EPR spectroscopy and has been applied to the binuclear copper(II) complexes of 5,5'-bis(3,7-dehydro-3,7-diazanonane-4,6-dione-1,9-diamine) (L1), 5,5'-bis(3,7-diazanonane-1,9-diamine) (L2), and 5-methyl-5-nitro-3,7-diazanonanedioate (L3). The complexes [Cu2L1].10H2O and [Cu2L2](ClO4)4 were also characterized by X-ray crystallography. (Cu2L1].10H2O: space group P1BAR; a = 7.669 (2), b = 8.757 (3), c = 10.596 (2) angstrom; alpha = 79.57 (3), beta = 83.36 (2), gamma = 89.17 (3)-degrees. [Cu2L2] (ClO4)4: space group P3(2)21; a = 13.671 (2), b = 13.671 (2), c = 13.929 (2) angstrom. There is excellent agreement between the X-ray crystal structures and the structures predicted by molecular mechanics and EPR spectroscopy, Electrochemical properties of the binuclear complexes are also reported.

The template reaction of {bis[(S)-2-(aminomethyl)pyrrolidine]}copper(II) with formaldehyde, nitroethane, and base in MeOH yields optically pure {1,7-bis[(S)-pyrrolidin-2-yl]-4-methyl-4-nitro-2,6-diazaheptane}-copper(II) ([Cu((S,S)-mnppm)]2+) in high yield. The same reaction with rac-2-(aminomethyl)pyrrolidine is also described. Preparative details and spectroscopic and electrochemical properties of the Cu(II) complexes and of the free ligands are reported and compared with structural, spectroscopic, and electrochemical data of the Cu(II) complex of the unsubstituted parent ligand 1,7-bis[(S)-pyrrolidin-2-yl]-2,6-diazaheptane (ppm). The crystal structure of [CU(PPM)]Cl.ClO4 has been determined by X-ray diffraction methods.

Reaction of the platinum(II) complex of the pendent-arm macrocycle 6,13-diammonio-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane with chlorine in aqueous solution does not lead simply to oxidation of the platinum(II) complex to a trans-dichloroplatinum(IV) complex. Instead, complete chlorination of the pendent primary amines occurs also, producing the trans-dichloroplatinum(IV) complex of a bis(dichloroamino) macrocycle. The dichloroamino complex was characterized by a crystal structure analysis, the first X-ray crystal structure of a dichloroamine; the perchlorate salt of trans-[Pt(2)Cl2](ClO4)2 crystallized in the P2(1)/n space group, with Z = 2, a = 10.612 (5) angstrom, b = 10.280 (3) angstrom, c = 12.792 (4) angstrom, and beta = 110.56 (3)-degrees. Inequivalent N-Cl bond lengths (1.718 (12) and 1.779 (12) angstrom) were observed. In aqueous acid, slow dechlorination occurs to produce the trans-dichloroplatinum(IV) complex of the precursor macrocycle, also characterized by a crystal structure analysis. The complex of the precursor macrocycle, trans-[Pt(1)Cl2]Cl2(ClO4)2.4H2O, crystallized in the P1BAR space group, with Z = 1, a = 7.308 (2) angstrom, b = 10.448 (2) angstrom, c = 10.672 (2) angstrom, alpha = 103.89 (1)-degrees, beta = 104.50 (1)-degrees, and gamma = 103.90 (1)-degrees.

The Pd(II) and Pt(II) complexes with triazolopyrimidine C-nucleosides L-1 (5,7-dimethyl-3-(2',3',5'-tri-O-benzoyl-beta-D-ribofuranosyl-s-triazolo)[4,3-a]pyrimidine), L-2 (5,7-dimethyl-3-beta-D-ribofuranosyl-s-triazolo [4,3-a]pyrimidine) and L-3 (5,7-dimethyl[1,5-a]-s-triazolopyrimidine), [Pd(en)(L-1)](NO3)(2), (Pd(bpy)(L-1)](NO3)(2), cis-Pd(L-3)(2)Cl-2, [Pd-2(L-3)(2)Cl-4]center dot H2O, cis-Pd(L-2)(2)Cl-2 and [Pt-3(L-1)(2)Cl-6] were synthesized and characterized by elemental analysis and NMR spectroscopy. The structure of the [Pd-2(L-3)(2)Cl-4]center dot H2O complex was established by Xray crystallography. The two L-3 ligands are found in a head to tail orientation, with a (PdPd)-Pd-... distance of 3.1254(17) angstrom.L-1 coordinates to Pd(II) through N8 and N1 forming polymeric structures. L-2 coordinates to Pd(II) through N8 in acidic solutions (0.1 M HCl) forming complexes of cis-geometry. The Pd(II) coordination to L-2 does not affect the sugar conformation probably due to the high stability of the C-C glycoside bond. (c) 2006 Elsevier B.V. All rights reserved. Inorganica Chimica Acta

As determined by X-ray crystallography, isoxazol-5(4H)-one derivatives 12–19 feature dihedral angles around the exocyclic C4=C6 double bonds of 26–90°. In the most highly twisted bis-tert-butylamino derivatives 18 and 19, the C4–C6 bonds are essentially single bonds. Density functional theory calculations at the B3LYP/6-31G(d) level with inclusion of a simulated solvent field, which helps stabilize zwitterionic structures, are in good agreement with the experimental crystallographic data. A good correlation between bond lengths and calculated π/π* orbital occupation quotients is observed. A good correlation between the twisting angle and the charge separation, measured by the calculated negative charge on the isoxazolone moiety, is also observed. Low barriers to rotation about the twisted exocyclic double bonds C4=C6 in compounds 13, 20, and 21 (ΔG ‡ = 15–16 kcal mol–1 (63–67 kJ mol–1)) were determined by dynamic 1H NMR coalescence measurements. The rotational barrier for 17 was estimated to be less than 10 kcal mol–1. The rotational barriers for compounds 10 and 18 were calculated to be ~8 kcal mol–1.

As determined by X-ray crystallography, Meldrum’s acid derivatives 5, 6, and 8 feature dihedral angles around the central C5=C7 double bond of 14–35°, whereas for the anion 9 this angle is 90°. Density functional theory and MP2 calculations are in agreement with the experimental X-ray data for compounds 5–8, but for anion 9 an angle of only ~65° is predicted. It is concluded that a part of the torsion is due to packing forces in the crystal. It is further concluded that these molecules undergo rapid rotation about the central CC bonds at room temperature (calculated activation barriers 5–14 kcal mol–1).

The diamino-substituted macrocyclic polyamine 6,13-diamino-6,13-dimethyl-1,4,8,11-tetra-azacyclotetradecane (L1) may act as a quadri-, quinque-, or sexi-dentate ligand to rhodium(III), with trans-[Rh(H2L1)Cl2]3+, cis-[Rh(HL1)Cl]3+, and [RhL1]3+ ions all isolated as perchlorate salts and characterized spectroscopically. Unlike the cobalt(III) analogue, which forms a trans isomer with the ligand L1 quinquedentate, only the cis isomer was observed with rhodium(III). The sexidentate complex adopts the common arrangement with the pendant primary amine groups in trans dispositions, confirmed by an X-ray crystal structure analysis: [RhL1][ClO4]3 crystallizes in the space group P21/c, with a= 16.700(3), b= 8.776(2), c= 17.896(3)A, and β= 114.58(1)°. The equatorial Rh–N bonds, 2.033–2.055 A, are the shortest reported for a saturated hexa-amine complex of rhodium(III); axial bonds are only slightly longer (2.055 and 2.058 A). This bond ‘compression’ is reflected in physical properties, with electronic maxima shifted to higher energy, and E½ for RhIII–RhII observed at a very negative potential. All complexes display irreversible one-electron reductions of the rhodium(III) centre in solution. Metal-centred reduction of the sexidentate complex with the aquated electron revealed a decay process which is rapid (kd 4 × 104 s–1), consistent with the voltammetric observations.

Both platinum(II) and palladium(II) complexes of 6,13-dimethyl-1,4,8,11-tetra-azacyclotetradecane-6,1 3-diamine (L1) as a quadridentate ligand have been prepared in facile reactions as perchlorate salts, and characterised by electronic and n.m.r. spectroscopy, and voltammetry. The platinum(II) complex, [Pt(H2L1)][ClO4]4, represents the first structurally characterised with a saturated macrocyclic tetra-amine ligand. It crystallises in the triclinic space group P, with a= 10.006(4), b= 8.691 (3), c= 8.173(2)A, α= 75.74(2), β= 79.00(3), and γ= 83.54(3)°, as does the complex [Pd(H2L1)][ClO4]4·6H2O, with a= 11.123(5), b= 8.609(5), c= 8.541 (3)A, α= 91.27(4), β= 96.09(3), and γ= 98.20(4)°. The cell of the palladium complex is derivative of that of the platinum simply by expansion, albeit with variations in some individual parameters. The Pt–N distances [2.045(7) and 2.043(6)A] and Pd–N distances [2.044(3) and 2.036(3)A] are slightly shorter than in non-cyclic MIIN4 analogues.

The pendant-arm macrocyclic hexa-amine 6,13-dimethyl-1,4,8,11-tetra-azacyclotetradecane-6,13-diamine (L2) co-ordinates to the oxovanadium(IV) cation in a quinquedentate manner. The complex [VO(L2)][ClO4]2 crystallises in the monoclinic space group C2/c, a= 25.220(4), b= 10.534(2), c= 16.321 (3)A, β= 94.53(1)°. The vanadium atom is displaced by 0.397 A above the macrocyclic plane of four nitrogens towards the oxo ligand, with a pendant amine occupying the trans site. Electron paramagnetic resonance and electronic spectra are consistent with the complex being a vanadyl penta-amine in solution as well as in the solid state.