Isolation, crystal structure and DFT study of 2,2,6,6-tetramethyl-4-oxo-piperidinium nitrate isolated from the stembark of Vitex doniana (Lamiaceae).

We present the results of the analysis of 2,2,6,6-tetramethyl-4-oxo-piperidinium nitrate isolated from the stem bark of Vitex doniana, a tree growing in Nigeria. The low-temperature molecular structure comprises one 2,2,6,6-tetramethyl-4-oxopiperidinium cation and one nitrate anion as one molecule in the asymmetric unit. The compound crystallizes in the monoclinic space group P21/n. A portion of the nitrate anion exhibits positional disorder with the main disorder component present 66.253(2) % of the time and the minor disorder component present 33.279(2) % of the time. In comparison with the previously reported room-temperature structure of C9H18N2O4 . The low-temperature structure shows similarity with the piperidinium ring adopting a slightly deformed chair conformation while the nitrate anion is disordered. DFT method was used to complement the experimental study.

Anticancer Activity of Urease Mimetic Cobalt (III) Complexes on A549-Lung Cancer Cells: Targeting the Acidic Microenvironment.

Tumour cells maintain a local hypoxic and acidic microenvironment which plays a crucial role in cancer progression and drug resistance. Urease is a metallohydrolases that catalyses the hydrolysis of urea into ammonia and carbon dioxide, causing an abrupt increase of pH. This enzymatic activity can be employed to target the acidic tumour microenvironment. In this study, we present the anticancer activities of urease mimetic cobalt (III) complexes on A549 cells. The cells were treated with different doses of cobalt (III) complexes to observe the cytotoxicity. The change in cellular morphology was observed using an inverted microscope. The cell death induced by these complexes was analysed through ATP proliferation, LDH release and caspase 3/7 activity. The effect of extracellular alkalinization by the cobalt (III) complexes on the efficacy of the weakly basic drug, doxorubicin (dox) was also evaluated. This combination therapy of dox with cobalt (III) complexes resulted in enhanced apoptosis in A549 cells, as evidenced by elevated caspase 3/7 activity in treated groups. The study confirms the urease mimicking anticancer activity of cobalt (III) complexes by neutralizing the tumour microenvironment. This study will motivate the applications of transition metal-based enzyme mimics in targeting the tumour microenvironment for effective anticancer treatments.

Synthesis and structure of 4-{[(E)-(7-meth-oxy-1,3-benzodioxol-5-yl)methyl-idene]amino}-1,5-dimethyl-2-phenyl-2,3-di-hydro-1H-pyrazol-3-one.

In the title compound, C20H19N3O4, the dihedral angles between the central pyrazole ring and the pendant phenyl and substituted benzene rings are 50.95 (8) and 3.25 (12)°, respectively, and an intra-molecular C-H⋯O link generates an S(6) ring. The benzodioxolyl ring adopts a shallow envelope conformation with the methyl-ene C atom as the flap. In the crystal, the mol-ecules are linked by non-classical C-H⋯O inter-actions, which generate a three-dimensional network. Solvent-accessible voids run down the c-axis direction and the residual electron density in these voids was modelled during the refinement process using the SQUEEZE algorithm [Spek (2015 ▸). Acta Cryst. C71, 9-18] within the structural checking program PLATON.

Copper-azide nanoparticle: a 'catalyst-cum-reagent' for the designing of 5-alkynyl 1,4-disubstituted triazoles.

A single pot, wet chemical route has been applied for the synthesis of polymer supported copper azide, CuN3, nanoparticles (CANP). The hybrid system was used as 'catalyst-cum-reagent' for the azide-alkyne cyclo-addition reaction to construct triazole molecules using substituted benzyl bromide and terminal alkyne. The electron donating group containing terminal alkyne produced 5-alkynyl 1,4-disubstituded triazole product whereas for alkyne molecule with terminal electron withdrawing group facilitate the formation of 1,4-disubstituted triazole molecule.

Reactivity trends of cobalt(III) complexes towards various amino acids based on the properties of the amino acid alkyl chains.

The reactivity of the cobalt(III) complexes dichlorido[tris(2-aminoethyl)amine]cobalt(III) chloride, [CoCl2(tren)]Cl, and dichlorido(triethylenetetramine)cobalt(III) chloride, [CoCl2(trien)]Cl, towards different amino acids (L-proline, L-asparagine, L-histidine and L-aspartic acid) was explored in detail. This study presents the crystal structures of three amino acidate cobalt(III) complexes, namely, (L-prolinato-κ2N,O)[tris(2-aminoethyl)amine-κ4N,N',N'',N''']cobalt(III) diiodide monohydrate, [Co(C5H8NO2)(C6H18N4)]I2·H2O, I, (L-asparaginato-κ2N,O)[tris(2-aminoethyl)amine-κ4N,N',N'',N''']cobalt(III) chloride perchlorate, [Co(C4H7N2O3)(C6H18N4)](Cl)(ClO4), II, and (L-prolinato-κ2N,O)(triethylenetetramine-κ4N,N',N'',N''')cobalt(III) chloride perchlorate, [Co(C4H7N2O3)(C6H18N4)](Cl)(ClO4), V. The syntheses of the complexes were followed by characterization using UV-Vis spectroscopy of the reaction mixtures and the initial rates of reaction were obtained by calculating the slopes of absorbance versus time plots. The initial rates suggest a stronger reactivity and hence greater affinity of the cobalt(III) complexes towards basic amino acids. The biocompatibility of the complexes was also assessed by evaluating the cytotoxicity of the complexes on cultured normal human fibroblast cells (WS1) in vitro. The compounds were found to be nontoxic after 24 h of incubation at concentrations up to 25 mM.

The crystal structure of the zwitterionic co-crystal of 2,4-di-chloro-6-{[(3-hy-droxy-prop-yl)azaniumyl]-meth-yl}phenolate and 2,4-di-chloro-phenol.

The title compound, C10H13Cl2NO2·C6H4Cl2O, was formed from the incomplete Mannich condensation reaction of 3-amino-propan-1-ol, formaldehyde and 2,4-di-chloro-phenol in methanol. This resulted in the formation of a co-crystal of the zwitterionic Mannich base, 2,4-di-chloro-6-{[(3-hy-droxy-prop-yl)azaniumyl]-meth-yl}phenolate and the unreacted 2,4-di-chloro-phenol. The compound crystallizes in the monoclinic crystal system (in space group Cc) and the asymmetric unit contains a mol-ecule each of the 2,4-di-chloro-phenol and 2,4-di-chloro-6-{[(3-hy-droxy-prop-yl)azaniumyl]-meth-yl}phenolate. Examination of the crystal structure shows that the two components are clearly linked together by hydrogen bonds. The packing patterns are most inter-esting along the b and the c axes, where the co-crystal in the unit cell packs in a manner that shows alternating aromatic di-chloro-phenol fragments and polar hydrogen-bonded channels. The 2,4-di-chloro-phenol rings stack on top of one another, and these are held together by π-π inter-actions. The crystal studied was refined as an inversion twin.

Energetic propane-1,3-diaminium and butane-1,4-diaminium salts of N,N'-dinitroethylenediazanide: syntheses, crystal structures and thermal properties.

The acidity of the amine H atoms and the consequent salt formation ability of ethylenedinitramine (EDNA) were analyzed in an attempt to improve the thermal stability of EDNA. Two short-chain alkanediamine bases, namely propane-1,3-diamine and butane-1,4-diamine, were chosen for this purpose. The resulting salts, namely propane-1,3-diaminium N,N'-dinitroethylenediazanide, C3H12N22+·C2H4N4O42-, and butane-1,4-diaminium N,N'-dinitroethylenediazanide, C4H14N22+·C2H4N4O42-, crystallize in the orthorhombic space group Pbca and the monoclinic space group P21/n, respectively. The resulting salts display extensive hydrogen-bonding networks because of the presence of ammonium and diazenide ions in the crystal lattice. This results in an enhanced thermal stability and raises the thermal decomposition temperatures to 202 and 221 °C compared to 180 °C for EDNA. The extensive hydrogen bonding present also plays a crucial role in lowering the sensitivity to impact of these energetic salts.

Deciphering composition and connectivity of a natural product with the assistance of MS and 2D NMR.

A complementary application of three analytical techniques, viz. multidimensional nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), and single-crystal X-ray diffractometry was required to identify and refine two natural products isolated from Millettia versicolor and solvent of crystallization. The two compounds, namely 3-(2H-1,3-benzodioxol-5-yl)-6-methoxy-8,8-dimethyl-4H,8H-pyrano[2,3-h]chromen-4-one, or durmillone, (I), and (2E)-1-(4-{[(2E)-3,7-dimethylocta-2,6-dien-1-yl]oxy}-2-hydroxyphenyl)-3-(4-hydroxyphenyl)prop-2-en-1-one, (II), could not be separated by routine column chromatography and cocrystallized in a 2:1 ratio with 0.13 molecules of ethanol solvent. Compound (II) and ethanol could not be initially identified by single-crystal X-ray analysis due to complex disorder in the aliphatic chain region of (II). Mass spectrometry ensured that (II) represented only one species disordered over several positions in the solid state, rather than several species cohabitating on the same crystallographic site. The atomic identification and connectivity in (II) were established by several 2D (two-dimensional) NMR techniques, which in turn relied on a knowledge of its exact mass. The derived connectivity was then used in the single-crystal analysis to model the disorder of the aliphatic chain in (II) over three positions and allowed identification of a partially occupied ethanol solvent molecule that was disordered over an inversion center. The disordered moieties were refined with restraints and constraints.

Bis(µ-N,N-di-allyl-dithio-carbamato)bis[(N,N-di-allyl-dithio-carbamato)cadmium].

The title compound, [Cd2(C7H10NS2)4], is a neutral dinuclear cadmium(II) complex bearing four bis N,N-di-allyl-di-thio-carbamate ligands coordinating to two CdII cations. In each of the monomeric subunits, there are four S atoms of two di-thio-carbamate ligands [Cd-S = 2.5558 (3), 2.8016 (3), 2.6050 (3) and 2.5709 (3) Å] that coordinate to one CdII atom in a bidentate mode. The dimers are located over an inversion centre bridged by two additional bridging Cd-S bonds [2.6021 (3) Å], leading to a substantial distortion of the geometry of the monomeric subunit from the expected square-planar geometry. The five-coordinate environment around each of the CdII ions in the dimer is best described as substanti-ally tetra-gonally distorted square pyramidal. The di-thio-carbamate groups are themselves planar and are also coplanar with the CdII ions. The negative charge on these groups is delocalized by resonance across the S atoms bound to the CdII cation. This delocalization of the π electrons in the di-thio-carbamate groups also extends to the C-N bonds as they reveal significant double bond character [C-N = 1.3213 (16) and 1.3333 (15) Å].

Polymorphism of dinitro[tris(2-aminoethyl)amine]cobalt(III) chloride.

Three polymorphs of bis(nitrito-κN)[tris(2-aminoethyl)amine-κ(4)N,N',N'',N''']cobalt(III) chloride, [Co(NO2)2(C6H18N4)]Cl, have been structurally characterized in the 100-300 K temperature range. Two orthorhombic polymorphs are related by a solid-state enantiotropic order-disorder k2 phase transition at ca 152 K. The third, monoclinic, polymorph crystallizes as a nonmerohedral twin. In the structure of the high-temperature (300 K) orthorhombic polymorph, the Co(III) complex cation resides on a crystallographic mirror plane, whereas the Cl(-) anion occupies a crystallographic twofold axis. In the unit cell of the monoclinic polymorph, the cationic Co(III) complex is in a general position, whose charge is balanced by two halves of two Cl(-) anions, each residing on a crystallographic twofold axis.

Charge-assisted hydrogen bonding in salts of 2-amino-1H-benzimidazole with 3-phenylpropynoic acid and oct-2-ynoic acid.

The 100 K structures of two salts, namely 2-amino-1H-benzimidazolium 3-phenylpropynoate, C7H8N3(+)·C9H5O2(-), (I), and 2-amino-1H-benzimidazolium oct-2-ynoate, C7H8N3(+)·C8H11O2(-), (II), both have monoclinic symmetry (space group P21/c) and display N-H...O hydrogen bonding. Both structures show packing with corrugated sheets of hydrogen-bonded molecules lying parallel to the [001] direction. Two hydrogen-bonded ring motifs can be identified and described with graph sets R(2)(2)(8) and R(4)(4)(16), respectively, in both (I) and (II). Computational chemistry calculations performed on both compounds show that the hydrogen-bonded ion pairs are more energetically favourable in the crystal structure than their hydrogen-bonded neutral molecule counterparts.

Pentane-1,5-diaminium dibromide.

The crystal structure of the title salt, C5H16N2(2+)·2Br(-), with Z = 12 and more unusually Z' = 3, forms part of a small group of crystal structures in the Cambridge Structural Database that are ammonium bromide salts. One of the diaminium cation chains in the asymmetric unit exhibits positional disorder, which was modelled using a suitable disorder model. This compound also exhibits organic-inorganic layering in its packing arrangement that is typical of this class of compound. An extensive complex three-dimensional hydrogen-bonding network is also identified. The hydrogen bonds evident in this crystal structure were identified as being most likely strong charge-assisted hydrogen bonds.

Bis[(1,1'-biphenyl-2,2'-di-yl)di-tert-butyl-phospho-nium] di-µ-chlorido-bis-[dichlorido-palladate(II)].

In the title compound, (C(20)H(26)P)(2)[Pd(2)Cl(6)], the Pd(II) atom within the hexachloridodipalladate(II) dianion has a square-planar geometry. It resides on a centre of inversion with the asymmetric unit containing half of the dianion and one phospho-nium cation. Only weak C-H⋯π inter-actions are present in the crystal structure.

(Acetato-κ(2)O,O')[2'-(di-tert-butyl-phosphanyl)-1,1'-biphenyl-κ(2)P,C(2)]palladium(II).

The structure of the title compound, [Pd(C(2)H(3)O(2))(C(20)H(26)P)], shows a distorted square-planar geometry for the Pd(II) atom, with significant deviations being evident owing to the asymmetric coordination mode of the acetate ligand. A weak intra-molecular C-H⋯O inter-action is noted. The crystal studied was a racemic twin.

Bis(acetonitrile-κN)dichlorido(η-cyclo-octa-1,5-diene)ruthenium(II) acetonitrile monosolvate.

In the title Ru(II) complex, [RuCl(2)(C(8)H(12))(C(2)H(3)N)(2)]·CH(3)CN, the metal ion is coordinated to the centers of each of the double bonds of the cyclo-octa-diene ligand, to two chloride ions (in cis positions) and to two N-atom donors (from MeCN mol-ecules) that complete the coordination sphere for the neutral complex. The coordination about the Ru(II) atom can thus be considered to be octa-hedral with a slightly trigonal distortion. There is also one acetonitrile solvent mol-ecule per mol-ecule which is outside the coordination sphere of the ruthenium atom.

Heptane-1,7-diaminium sulfate mono-hydrate.

The crystal structure of the title compound, C(7)H(20)N(2) (2+)·SO(4) (2-)·H(2)O, is presented, with particular focus on the packing arrangement in the crystal structure and selected hydrogen-bonding inter-actions that the compound forms. The crystal structure exhibits parallel stacking of the diammonium dication in its packing arrangement, together with inorganic-organic layering that is typical of these n-alkyl-diammonium salts. An intricate three-dimensional hydrogen-bonding network exists in the crystal structure where the hydrogen bonds link the cation and anion layers together through the sulfate anions and the water mol-ecules.

Butane-1,4-diammonium bis(perchlorate).

The butane-1,4-diammonium cation of the title compound, C(4)H(14)N(2) (2+)·2ClO(4) (-), lies on a special position of site symmetry 2/m, whereas the perchlorate anion is located on a crystallographic mirror plane. An intricate three-dimensional hydrogen-bonding network exists in the crystal structure with each H atom of the ammonium group exhibiting bifurcated inter-actions to the perchlorate anion. Complex hydrogen-bonded ring and chain motifs are also evident, in particular a 50-membered ring with graph-set notation R(10) (10)(50) is identified.

Heptane-1,7-diaminium dinitrate.

In the title molecular salt, C(7)H(20)N(2) (2+)·2NO(3) (-), the crystal structure exhibits an unusual back-to-back paired double-stacked packing arrangement culminating in an overall double zigzag pattern of the dications. The nitrate anions form a ring around one pair of double-stacked dications. An intricate three-dimensional N-H⋯O and N-H⋯(O,O) hydrogen-bonding network exists in the crystal structure.

Decane-1,10-diaminium dinitrate.

The crystal structure of the title compound, C(10)H(26)N(2) (2+)·2NO(3) (-), exhibits a back-to-back paired double-stacked packing arrangement culminating in an overall double zigzag pattern of the dications. Each pair of double-stacked dications is surrounded by a ring of ten nitrate anions. An intricate three-dimensional N---H...O and N---H...(O,O) hydrogen-bonding network exists in the crystal structure.

Ethane-1,2-diammonium dibromide: a redetermination at 100†K.

In the redetermined [for the previous study, see Søtofte (1976 ▶). Acta Chem. Scand. Ser. A, 30, 309-311] crystal structure of the title compound, C(2)H(10)N(2) (2+)·2Br(-), the H atoms have been located and the hydrogen-bonding scheme is described. The ethane-1,2-diammonium cation lies over a crystallographic inversion centre and straddles a crystallographic mirror plane with the C and N atoms in special positions. In the crystal, the cations and anions are linked by N-H⋯Br and N-H⋯(Br,Br) hydrogen bonds, which generate various ring and chain motifs including an R(10) (5)(32) loop.