Band 239, Heft 3-4

Trimethylamine N-oxide, Me 3 N (+) O (−) , is an important molecule in biology and medicine. Herein, a survey of the interactions involving the oxide-O atom in crystals containing derivatives of Me 3 N (+) O (−) , namely RR′R″N (+) O (−) , is presented; R,R′, R″ = alkyl and/or aryl. A total of 119 RR′R″N (+) O (−) molecules were analysed for the supramolecular interactions involving the oxide-O atom. Hydrates form the largest class of crystals, comprising over 40 % of the 91 crystals investigated, a value slightly higher than expectation. Over 80 % of molecules had at least one O–H⋯O (−) (oxide) hydrogen bond: 3, 45 and 33 % of all molecules had three, two or one O–H⋯O (−) (oxide) hydrogen bonds, respectively. Further, nearly 15 % of molecules formed at least one N–H⋯O (−) (oxide) hydrogen bond, sometimes operating in concert with O–H⋯O (−) (oxide) hydrogen bonds. The overwhelming majority of molecules featured inter- and/or intra-molecular supporting C–H⋯O (−) (oxide) contacts so that a diverse range of supramolecular interaction patterns is apparent, a situation made more complicated by the appearance of different supramolecular association patterns often observed for independent molecules in crystals with more than one molecule in the crystallographic asymmetric-unit. Of the 6 % of molecules devoid of conventional A–H⋯O (−) (oxide) hydrogen bonds, all formed three or four inter-/intra-molecular C–H⋯O (−) (oxide) contacts usually characterised by at least one short H⋯O (−) (oxide) distance.

Ca 3 Ru 3 Zn 13 was synthesized from the elements in a tantalum tube in a muffle furnace. The sample was annealed to 1123 K followed by slow cooling to enhance crystal growth. Ca 3 Ru 3 Zn 13 was characterized through a Guinier powder pattern. The structure was refined from single crystal X-ray diffractometer data: new type, Pbcn , a = 522.92(5), b = 1792.72(14), c = 2789.6(2) pm, wR 2 = 0.0590, 3451 F 2 values, 177 variables. One can describe the Ca 3 Ru 3 Zn 13 structure by a stacking of closest packed layers of compositions Ca 6 Zn 10 , Ca 6 Zn 12 and Ru 6 Zn 15 . The calcium atoms have high coordination numbers: Ca1@Zn 13 Ru 3 Ca 2 , Ca2@Zn 15 Ru 4 Ca, Ca3@Zn 15 Ru 4 Ca and Ca4@Zn 15 Ru 4 Ca. The shortest interatomic distances occur between the ruthenium and zinc atoms (255–273 pm). The Ru1@Zn 8 , Ru2@Zn 10 and Ru3@Zn 8 polyhedra condense via common edges to the [Ru 3 Zn 13 ] substructure which hosts the calcium atoms. The zinc substructure consists of 15 crystallographically independent zinc sites with a broader range of Zn–Zn distances (255–307 pm).

Borate-phosphates exhibit a wide range of compositional and structural diversity, making them ideal hosts for luminescent materials. In this work, a new borate-phosphate compound CsNa 2 Dy 2 (BO 3 )(PO 4 ) 2 has been prepared under high temperature solution growth method. It crystallizes in an orthorhombic space group Cmcm with the following lattice parameters determined by single-crystal X-ray diffraction: a  = 6.9709(5), b  = 14.9699(11), c  = 10.6480(8) Å, z  = 4. Its structure contains isolated BO 3 planar triangles and PO 4 tetrahedra, which are interconnected by Cs + , Na + and Dy 3+ ions. Solid solutions of CsNa 2 Y 2(1− x ) Dy 2 x (BO 3 )(PO 4 ) 2 ( x  = 0 − 0.08) are prepared and exhibit a yellow emissive luminescence by near-UV excitation due to the 4 F 9/2 → 6 H (13/2, 15/2) transitions of Dy 3+ . The optimized concentration of Dy 3+ is x  = 0.01, and if over this critical value, the luminescent intensity will decrease due to concentration quenching. The Commission International de L’Eclairage (CIE) coordinates for CsNa 2 Y 1.98 Dy 0.02 (BO 3 )(PO 4 ) 2 are ( x  = 0.377, y  = 0.404), corresponding to yellow color. The prepared phosphor may serve as a yellow phosphor for NUV-excited LEDs.

The presence of ns 2 stereo-chemical active lone electron pairs (LEPs) causes asymmetric atomic environments around a given p -block cation, leading to change the crystal chemistry of a respective system. Here we report a series of mullite-type compounds to understand at what extend Sr 2+ replaces the stereochemical active Pb 2+ cation in (Pb 1− x Sr x )MnBO 4 . Each member of the solid solution has been synthesized by conventional solid-state method. The polycrystalline samples are characterized using X-ray powder diffraction followed by Rietveld refinement. Substitution of Pb 2+ with Sr 2+ leads to contraction of the a lattice parameter with slight elongation in the b and c direction. For a difference of 1 pm of the ionic radius between Sr 2+ and Pb 2+ , the cell volume contracts about 4 % between the end members as the spatial requirement of the LEP activity in the MBO 4 2− channels significantly decreases. Within the solid solution, two distinct Pb/Sr–O 2 bond distances significantly differ, which gradually decreases with increasing strontium content leading to a more symmetric coordination around strontium. The calculated BVS of Pb 2+ /Sr 2+ exhibits a linear correlation with the Wang–Liebau eccentricity parameter, indicating to an increased bonding ability cation. The vibrational properties are characterized by both Raman and FTIR spectroscopy, complementing the XPRD results. Electronic band gaps of selected (Pb 1− x Sr x )MnBO 4 samples were obtained from diffuse reflectance spectroscopy data. Additionally, the Sr containing samples show higher thermal stability than the Pb containing counterparts.

We report on the synthesis, structure determination, and characterization of a new series of compounds Ln CdB 6 O 10 (OH) 3 ( Ln  = Sm–Er). Syntheses were carried out in a Walker-type multianvil device at 7 GPa and 650 °C. Structure determinations revealed the coexistence of an orthorhombic and a monoclinic polymorph, depending on the ionic radius of the lanthanoid cation. The orthorhombic structural variants crystallize non-centrosymmetrically in the space group Pna 2 1 (no. 33), while the monoclinic modifications crystallize in space group P 2 1 / c (no. 14). Both modifications display a layered crystal structure built up by a repeating [B 6 O 13 ] 8− building block as their main structural feature.

Methenolone and drostanolone are two popular synthetic anabolic-androgenic agents and dihydrotestosterone derivatives which belong to the steroid family. Two esterified prodrugs of methenolone and drostanolone, in the form of methenolone and drostanolone enanthate, have been described from a structural point of view. The crystal structure of drostanolone enanthate was determined by single crystal X-ray diffraction, while the crystal structure of methenolone enanthate was solved by the powder X-ray diffraction technique. The nature and magnitudes of intermolecular interactions were analysed quantitatively by means of crystal lattice energies and Hirshfeld surfaces.