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Penta-kis-(μ3-N,2-di-oxido-benzene-1-car-box-imid-ato)di-μ2-formato-penta-kis-(1H-imidazole)-methanolpenta-manganese(III)man-gan-ese(II)-methanol-water (1/3.36/0.65)

The title compound, [Mn6(C7H4NO3)5(CHO2)2(C3H4N2)5(CH3OH)]·3.36CH3OH·0.65H2O, or Mn(II)(O2CH)2[15-MCMn(III)N(shi)-5](Im)5(MeOH)·3.36MeOH·0.65H2O (where MC is metallacrown, shi(3-) is salicyl-hydroximate, Im is imidazole and MeOH is methanol), contains five Mn(III) ions as members of the metallacrown ring and an Mn(II) atom bound in the central cavity. The central Mn(II) atom is seven-coordinate with a geometry best described as between face-capped trigonal-prismatic and face-capped octa-hedral. Three Mn(III) ions of the metallacrown ring are six-coordinate with distorted octa-hedral geometries. Of these six-coordinate Mn(III) ions, two have mirror-plane configurations, while the other has a Δ absolute stereoconfiguration. The remaining two Mn(III) ions have a coordination number of five with a distorted square-pyramidal geometry. The five imidazole ligands are bound to five different Mn(III) ions. Disorder is observed for one of the coordinating imidazole ligands, as the imidazole ligand is disordered over two alternative mutually exclusive positions in a ratio of 0.672 (9) to 0.328 (9). The inter-stitial voids between the main mol-ecules that constitute the structure are mostly filled with methanol mol-ecules that form hydrogen-bonded chains. Some of the sites of the non-coordinated methanol mol-ecules are not fully occupied, with the remainder of the volume either empty or taken up by ill-defined close to amorphous content. One site was refined as being taken up by either two or one methanol mol-ecules, with an occupancy ratio of 0.628 (5) to 0.343 (5). This disorder might thus be correlated with the disorder of the imidazole ring (an N-H⋯O hydrogen bond between the major moieties of the imidazole and the methanol mol-ecules is observed). On the other side of the disordered imidazole ring the chain of partially occupied methanol mol-ecules originates that extends via O-H⋯O hydrogen bonds to the metal-coordinated methanol mol-ecule. The three partially occupied methanol mol-ecules were refined to be disordered with two water mol-ecules to take two residual electron density peaks into account (the exact nature of these weak residual electron density peaks cannot be deduced from the X-ray diffraction data alone, the assignment as water is tentative). The occupancy rate for the methanol mol-ecules refined to 0.480 (7). The occupancy rate of the two water mol-ecules refined to 0.34 (1) and 0.31 (2) for each site.

Tris(5-amino-1H-1,2,4-triazol-4-ium) dihydrogenphosphate hydrogen-phosphate trihydrate

In the crystal structure of the title molecular salt, 3C2H5N4(+)·HPO4(2-)·H2PO4(-)·3H2O, the phosphate-based framework is built upon layers parallel to (010) made up from the H2PO4(-) and HPO4(2-) anions and water mol-ecules, which are inter-connected through O-H⋯O hydrogen bonds. The organic cations are located between the phosphate-water layers and are connected to them via N-H⋯O hydrogen bonds. The bond-length features are consistent with an imino resonance form for the exocyclic amino group, as is commonly found for a C-N single bond involving sp(2)-hybridized C and N atoms.

4-{[2-(2,4-Dinitro-phen-yl)hydrazinyl-idene](phen-yl)meth-yl}-5-methyl-2-phenyl-1H-pyrazol-3(2H)-one ethanol monosolvate

In the title compound, C₂₃H₁₈N₆O₅·C₂H₆O, all three benzene rings lie in an approximate plane [maximum deviation = 0.2688 (16) Å] that makes an angle of 53.56 (3)° with the plane of the pyrazolone ring. Intra­molecular N—H⋯O hydrogen bonds occur. In the crystal, the ethanol solvent mol­ecule links adjacent mol­ecules through N—H⋯O—H⋯O hydrogen bonds, leading to an infinite chain along the c-axis direction. The ethyl group of the ethanol solvent mol­ecule is disordered over two set of sites in a 0.762 (5):0.238 (5) ratio.

Poly[dibutyl-ammonium [nonamethylbis-(μ(3)-sulfato-κ(3)O:O':O'')tristannate(IV)]]

In the structure of the title coordination polymer, {(C₈H₂₀N)[Sn₃(CH₃)₉(SO₄)₂]}_n, each of the three Sn^IV atoms is coordinated in a trigonal–bipyramidal manner by three methyl groups in the equatorial plane and by two O atoms of SO₄²⁻ anions in the axial positions. The μ₃-bridging mode of the sulfate anions leads to the formation of corrugated anionic layers parallel to (100). The uncoordinating O atom of one of the two SO₄²⁻ anions is N—H⋯O hydrogen-bonded to the dibutyl­ammonium cation inter­connecting the anionic sheets. The structure is partially disordered. The dibutyl ammonium ion is found on two positions with an occupancy ratio of 0.525 (10):0.475 (10), and one sulfate group with three connecting trimethyl stannyl groups is also positionally disordered over two sets of sites with an occupancy ratio of 0.725 (4):0.275 (4).

Poly[tetra-kis-(dimethyl-formamide)tris(μ(4)-terephthalato)trimagnesium]

The title framework compound, [Mg(3)(C(8)H(4)O(4))(3)(C(3)H(7)NO)(4)](n) or [Mg(3)(bdc)(3)(DMF)(4)](n), was obtained as a side product of the solvothermal reaction of magnesium nitrate, terephthalic acid (bdcH(2)), and 1,3-bis-(4-pyrid-yl)propane in a 1:2:1 ratio in dimethyl-formamide (DMF). The asymmetric unit consists of three Mg(II) cations, three terephthalate anions, and four coordinating DMF mol-ecules. One of the four DMF mol-ecules was refined as disordered over two mutually exclusive positions, with an occupancy rate for the major moiety of 0.923 (4). The three Mg(II) cations possess distorted octa-hedral coordination geometries that form linear Mg trimers. Of the three Mg(II) cations, the central Mg(II) is octa-hedrally coordinated by six different carboxyl-ate O atoms. The terminal Mg(II) cations are bonded to four O atoms of three bdc linkers and to two O atoms of coordinating DMF mol-ecules. The compound has a two-dimensional 3(6)-network structure parallel to (001) that is formed by connection of the Mg trimers as distorted octa-hedral nodes to the bdc ligands as linkers.

Bis(tetra-ethyl-ammonium) oxalate dihydrate

The title compound, 2C(8)H(20)N(+)·C(2)O(4) (2-)·2H(2)O, synthesized by neutralizing H(2)C(2)O(4)·2H(2)O with (C(2)H(5))(4)NOH in a 1:2 molar ratio, is a deliquescent solid. The oxalate ion is nonplanar, with a dihedral angle between carboxyl-ate groups of 64.37 (2)°. O-H⋯O hydrogen bonds of moderate strength link the O atoms of the water mol-ecules and the oxalate ions into rings parallel to the c axis. The rings exhibit the graph-set motif R(4) (4)(12). In addition, there are weak C-H⋯O inter-actions in the crystal structure.

Bis(4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olato-κ(2)O,O')bis-(ethanol-κO)cobalt(II)

The title compound, [Co(C₁₇H₁₃N₂O₂)₂(C₂H₅OH)₂], is a Co^II complex with two 4-benzoyl-3-methyl-1-phenyl-1H-pyrazol-5-olate (BMPP) ligands and two coordinating ethanol mol­ecules. In the asymmetric unit, there are two half mol­ecules, with the Co^II atoms located on inversion centres. The two cobalt complexes have slightly different geometries and in one, the ethyl group of the ethanol is disordered over two sets of sites [occupancy ratio 0.757 (7):0.243 (7)]. Each BMPP ligand is deprotonated with the negative charge delocalized. The hy­droxy group of each ethanol mol­ecule forms hydrogen bonds with a pyrazole N atom in an adjacent BMPP ligand. Weaker C—H⋯O and C—H⋯N inter­actions link the mol­ecules into a three-dimensional structure.

Bis(adamantan-1-aminium) hydrogen phosphate fumaric acid sesquisolvate

The asymmetric unit of the title compound, 2C₁₀H₁₈N⁺·HPO₄²⁻·1.5C₄H₄O₄, contains two adamantan-1-aminium cations, one hydrogen phosphate anion, and one and a half mol­ecules of fumaric acid, one of which exhibits crystallographic inversion symmetry. Each HPO₄²⁻ anion is hydrogen bonded, via all of its O atoms, to four NH₃⁺ groups of the adamantan-1-aminium cations, forming chains along [100]. These chains are, in turn, inter­connected via a set of O—H⋯O hydrogen bonds involving the fumaric acid solvent mol­ecules, forming layers parallel to (001). Weak C—H⋯O inter­actions lead to a consolidation of the three-dimensional set-up.

Dimethyl-ammonium 3-carb-oxy-benzoate

The asymmetric unit of the title organic salt, C₂H₈N⁺·C₈H₅O₄⁻, consists of two dimethyl­ammonium cations and two 3-carb­oxy­benzoate anions. The 3-carb­oxy­benzoate anions are linked via strong inter­molecular and nearly symmetrical O—H⋯O hydrogen bonds forming infinite chains parallel to [111]. Neighbouring chains are further connected by the dimethyl­ammonium cations via N—H⋯O bonds, resulting in a double-chain-like structure. The dihedral angles of all carboxylate groups with respect to the phenylene rings are in the range 7.9 (1)–20.48 (9)°.

4,4'-Bipyridine-terephthalic acid (1/1)

The asymmetric unit of the title compound, C(10)H(8)N(2)·C(8)H(6)O(4), consists of one half-mol-ecule of each moiety, 4,4'-bipyridine (bpy) and terephthalic acid (bdc), both being located on crystallographic inversion centers. They are linked together via strong inter-molecular O-H⋯N hydrogen bonds, forming infinite chains propagating along [1-21]. The chains are further connected through C-H⋯O inter-actions giving sheets in (012). The sheets are linked via π-π inter-actions between the bpy rings and the bdc-bpy rings [centroid-centroid distances = 3.690 (2) and 3.869 (2) Å], resulting in the formation of a three-dimensional supra-molecular layer-like structure.

A biomimetic domino reaction for the concise synthesis of capreomycidine and epicapreomycidine

The non-proteinogenic amino acids capreomycidine and epicapreomycidine are constituents of antibiotically active natural products, but the synthesis of these unusual cyclic guanidine derivatives is challenging. The biosynthesis of capreomycidine has therefore been employed as a guideline to develop a concise biomimetic synthesis of both epimeric amino acids. The resulting domino-guanidinylation-aza-Michael-addition reaction provides the most convenient access to these amino acids in racemic form. Attempts to dissect the domino reaction into two separate transformations for a stereocontrolled version of this synthetic approach have also been made. The synthesized didehydro-arginine derivatives with urethane-protected guanidine moieties did not undergo the aza-Michael-addition anymore. These results may have wider implications for the 1,4-addition of guanidines to α,β-unsaturated carbonyl compounds, particularly to didehydro amino acids.

Invariom modeling of ceftazidime pentahydrate: molecular properties from a 200 second synchrotron microcrystal experiment

The structure of ceftazidime pentahydrate, a third generation cephalosporin antibiotic, is reported. Data collection was carried out in a remarkably short time with synchrotron radiation and the latest detector technology, illustrating that single-crystal X-ray diffraction can be used as a technique for screening hundreds of compounds in a short amount of time. Structure refinement made use of invarioms, namely non-spherical scattering factors, which allow more information to be derived from a diffraction experiment. Properties that can be screened are bond-topological parameters, empirical hydrogen-bond energies, molecular dipole moments and electrostatic potentials.

3-Methyl-1-phenyl-4-[(phen-yl)(2-phenyl-hydrazin-1-yl)meth-ylidene]-1H-pyrazol-5(4H)-one

The title compound, C₂₃H₂₀N₄O, is a heterocyclic phenyl­hydrazone Schiff base with a pyrazole moiety. In the crystal, a variety of inter­actions occur, including N—H⋯π and π–π stacking between the phenyl ring of the phenyl­hydrazinyl group and its symmetry-generated equivalent [centroid–centroid distance = 3.6512 (7) Å].