rac-1-(2-Amino­carbonyl-2-bromo­eth­yl)pyridinium bromide

In the crystal structure of the title compound, C8H10BrN2O+·Br−, inter­molecular N—H⋯Br hydrogen bonds link the mol­ecules into infinite chains along [001]. The inclined angle between the pyridine ring plane and the plane defined by the acid amide group is 63.97 (4)°

Methyl 3,5,5,6,8,8-hexa­methyl-5,6,7,8-tetra­hydro­naphthalene-2-carboxyl­ate (AHTN–COOMe)

Crystals of the title compound, C18H26O2, were grown from ethyl acetate. Due to the racemic precursor, the title compound is also obtained as a racemate. Disorder was observed during structure refinement, originating from two possible half-chair conformations of the non-aromatic ring. The disorder was refined by introducing split positions in the cyclo-hexane ring regarding the two possible R and S-enantiomers at the chiral CH group [ratio 0.744 (3):0.256 (3)]. The crystal structure features pairs of inversion-related molecules connected by pairs of non-classical C—H⋯O hydrogen bonds

(3S,11Z)-14,16-Dihy­droxy-3-methyl-3,4,5,6,9,10-hexa­hydro-1H-2-benz­oxacyclo­tetra­decine-1,7(8H)-dione (cis-zearalenone): a redetermination

The title compound, also known as cis-zearalenone (cis-ZEN), C18H22O5, has already been reported elsewhere [Griffin et al. (1981 ▶). ACA Ser. 29, 35], but no atomic coordinates are publicly available. The mol­ecule is of inter­est with respect to its toxicity. In the crystal, intra­molecular O—H⋯O hydrogen bonds stabilize the mol­ecular conformation, while inter­molecular O—H⋯O hydrogen bonds link the mol­ecules to form infinite chains along the [110] and [1-10] directions. The absolute configuration has been assigned by reference to an unchanging chiral centre in the synthetic procedure

Ergotaminine

The title compound {systematic name: (6aR,9S)-N-[(2R,5S,10aS,10bS)-5-benzyl-10b-hy­droxy-2-methyl-3,6-dioxoocta­hydro-8H-oxazolo[3,2-a]pyrrolo­[2,1-c]pyrazin-2-yl]-7-methyl-4,6,6a,7,8,9-hexa­hydro­indolo[4,3-fg]quinoline-9-carboxamide}, C33H35N5O5, was formed by an epimerization reaction of ergotamine. The non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar [maximum deviation = 0.317 (4) Å] and shows an envelope conformation, whereas ring D, involved in an intra­molecular N—H⋯N hydrogen bond exhibits a slightly distorted chair conformation. The structure displays chains running approximately parallel to the diagonal of bc plane that are formed through N—H⋯O hydrogen bonds

Structure and properties of fluorinated and non‐fluorinated Ba‐coordination polymers – the position of fluorine makes the difference

As the most electronegative element, fluorine has a strong influence on material properties such as absorption behaviour or chemical and thermal stability. Fluorine can be easily integrated into coordination polymers (CPs) via a fluorinated acetate, here trifluoroacetate in Ba(CF3COO)2, or directly via a metal fluorine bond (BaF(CH3COO)). In the present study both possibilities of fluorine integration were tested and their effect on structure and properties of barium coordination polymers was investigated in comparison with the non-fluorinated barium acetate (Ba(CH3COO)2). In addition to the study of their thermal behaviour and their decomposition temperature, the CPs structures were tested for their application as possible anode materials in lithium ion batteries and for their sorption of water and ammonia. The properties of the CPs can be traced back to the individual structural motifs and could thus trigger new design ideas for CPs in LIBs and/or catalysis.HU BerlinBAMPeer Reviewe

Ergometrinine

The absolute configuration of ergometrinine, C19H23N3O2 {systematic name: (6aR,9S)-N-[(S)-1-hy­droxy­propan-2-yl]-7-methyl-4,6,6a,7,8,9-hexa­hydro­indolo[4,3-fg]quinoline-9-carb­ox­amide}, was established based on epimerization reaction of ergometrine, which was followed by preparative HPLC. The non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar [maximum deviation = 0.271 (3) Å] and shows an envelope conformation, whereas ring D, involved in an intra­molecular N—H⋯N hydrogen bond, exibits a slightly distorted chair conformation. The structure displays undulating layers in the ac plane formed by O—H⋯O and N—H⋯O hydrogen bonds

<i>In situ</i> investigation of controlled polymorphism in mechanochemistry at elevated temperature†

Mechanochemistry routinely provides solid forms (polymorphs) that are difficult to obtain by conventional solution-based methods, making it an exciting tool for crystal engineering. However, we are far from identifying the full scope of mechanochemical strategies available to access new and potentially useful solid forms. Using the model organic cocrystal system of nicotinamide (NA) and pimelic acid (PA), we demonstrate with variable temperature ball milling that ball milling seemingly decreases the temperature needed to induce polymorph conversion. Whereas Form I of the NA:PA cocrystal transforms into Form II at 90 °C under equilibrium conditions, the same transition occurs as low as 65 °C during ball milling: a ca 25 °C reduction of the transition temperature. Our results indicate that mechanical energy provides a powerful control parameter to access new solid forms under more readily accessible conditions. We expect this ‘thermo-mechanical’ approach for driving polymorphic transformations to become an important tool for polymorph screening and manufacturing

Too much water? Not enough? In situ monitoring of the mechanochemical reaction of copper salts with dicyandiamide

In situ monitoring of mechanochemical reactions between dicyandiamide (DCD) and CuX2 salts (X = Cl-, NO3-), for the preparation of compounds of agrochemical interest, showed the appearance of a number of phases. It is demonstrated that milling conditions, such as the amount of water added in wet grinding and/or the milling frequency, may affect the course of the mechanochemical reactions, and drive the reaction towards the formation of different products. It has been possible to discover by in situ monitored experiments two novel crystalline forms, namely the neutral complexes [Cu(DCD)(2)(OH2)(2)(NO3)(2)] (2) and [Cu(DCD)(2)(OH2)Cl-2]center dot H2O (4), in addition to the previously known molecular salt [Cu(DCD)(2)(OH2)(2)] [NO3](2)center dot 2H(2)O (1, DIVWAG) and neutral complex [Cu(DCD)(2)(OH2)Cl-2] (3, AQCYCU), for which no synthesis conditions were available. Compounds 2 and 4 were fully characterized via a combination of solid-state techniques, including X-ray diffraction, Raman spectroscopy and TGA