Space group revsion of the triclinic polymorph of salicyl­aldehyde azine

The structure of the title compound, C₁₄H₁₂N₂O₂ {systematic name: 2,2′-[hydrazinediylidenebis(methanylyl­idene)]diphen­ol}, has already been determined in the triclinic space group P with Z = 4 [El-Medani, Aboaly, Abdalla & Ramadan (2004). Spectrosc. Lett. 37, 619–632]. However, the correct space group should be P2₁/c with Z = 4. This structure is a new polymorph of the already known monoclinic polymorph of salicyladehyde azine, which crystallizes in space group P2₁/n with Z = 2. The benzene rings form a dihedral angle of 46.12 (9)°. Two intramolucular O—H...N hydrogen bonds occur.

Bromido(2,4,6-trimethyl­phen­yl)mercury(II)

Mol­ecules of the title compound, [HgBr(C₉H₁₁)], are located on a crystallographic twofold rotation axis. Due to the mol­ecular symmetry, the Hg^II atom is linearly coordinated by the ipso-C of the mesityl group and the Br atom. In the crystal, mol­ecules lie in planes parallel to (001).

trans-Dichloridobis(triphenyl­phosphane-κP)palladium(II) benzene hemisolvate

The title complex, [PdCl₂(C₁₈H₁₅P)₂]·0.5C₆H₆, has the Pd^II ion in a square-planar coordination mode (r.m.s. deviation for Pd, P and Cl atoms = 0.024 Å) with the PPh₃ and Cl ligands mutually trans. The benzene solvent mol­ecule is located about a crystallographic inversion centre. The title complex is isostructural with trans-dichloridobis(triphenyl­phosphane)­palladium(II) 1,4-dichloro­benzene sesquisolvate [Kitano et al. (1983). Acta Cryst. C39, 1015–1017].

Dimethyl 6-acetyl-2-methyl-1,2-dihydroquinoline-2,4-dicarboxyl­ate

In the title compound, C₁₆H₁₇NO₅, the dihydro­pyridine ring adopts a sofa conformation. In the crystal, inter­molecular N—H...O hydrogen bonds link the mol­ecules into chains running along the b axis.

Poly[[μ-ethane-1,2-diyl bis­(pyridine-3-carboxyl­ate)](μ-tetra­fluorido­borato)silver(I)]

In the title compound, [Ag(BF₄)(C₁₄H₁₂N₂O₄)]_n, the coordination of the Ag⁺ ion is trigonal–bipyramidal with the N atoms of two ethane-1,2-diyl bis­(pyridine-3-carboxyl­ate) ligands in the apical positions and three F atoms belonging to different tetra­fluorido­borate anions in the equatorial plane. The material consists of infinite chains of [Ag(C₁₄H₁₂N₂O₄)] units running along [001], held together by BF₄⁻ bridging anions.

Iodido(tri-tert-butyl­phosphane-κP)gold(I)

The Au^I atom of the title compound, [AuI(C₁₂H₂₇P)], shows an almost linear coordination, with a P—Au—I angle of 178.52 (3)° [Au—P = 2.2723 (14) Å and Au—I = 2.5626 (6) Å].

Dimethyl 6-bromo-2-methyl-1,2-di­hydro­quinoline-2,4-dicarboxyl­ate

In the title compound, C₁₄H₁₄BrNO₄, the dihydro­pyridine ring adopts a screw-boat conformation. In the crystal, pairs of N—H...O hydrogen bonds link the mol­ecules into inversion R₂²(10) dimers.

A triclinic polymorph of bis­(μ-di-tert-butyl­phosphanido)bis­[(di-tert-butyl­phosphane)palladium(I)]

A new polymorph of the title compound, [Pd₂(C₈H₁₈P)₂(C₈H₁₉P)₂], has been found. It belongs to the triclinic P-1 space group, whereas the known form [Leoni, Sommovigo, Pasquali, Sabatino & Braga (1992), J. Organo­met. Chem. 423, 263–270] crystallizes in the monoclinic C2/c space group. The title compound features a dinuclear palladium complex with a planar central Pd₂(μ-P)₂ core (r.m.s. deviation = 0.003 Å). The Pd—Pd distance of 2.5988 (5) Å is within the range of a Pd^I—Pd^I bond. The mol­ecules of both polymorphs are located on a crystallographic centre of inversion. The mol­ecular conformations of the two polymorphs are essentially identical. The crystal packing patterns, on the other hand, are slightly different.

Redetermination of (acetonitrile-κN)dicarbon­yl(η⁵-cyclo­penta­dien­yl)iron(II) tetra­fluoridoborate

The crystal structure of the title compound, [Fe(C₅H₅)(CH₃CN)(CO)₂]BF₄, of which only the coordinates of the non-H atoms of the cation have previously been reported [Fadel et al. (1979). Z. Anorg. Allg. Chem. 453, 98–106] has been redetermined. The Fe^II atom in the complex cation is coordinated by a cyclo­penta­dienyl ring, two carbonyl ligands and an acetonitrile mol­ecule displaying a three-legged piano stool structure. Three of the four F atoms of the BF₄⁻ anion are disordered over two sets of sites, with a site-occupancy factor of 0.709 (10) for the major occupied site.

Sodium penta­fluoro­phenyl­borate

The crystal structure of the title compound, Na[(C₆F₅)BH₃], is composed of discrete anions and cations. The sodium cations are surrounded by four anions with three short Na...B [2.848 (8), 2.842 (7) and 2.868 (8) Å] and two short Na...F contacts [2.348 (5) and 2.392 (5) Å], forming a three-dimensional network. The anion is the first structural example of a pentafluorophenyl ring carrying a BH₃ group.

1,3-Bis(2,6-diisopropyl­phen­yl)-1H-imidazol-3-ium chloride dichloro­methane disolvate

In the title compound, C₂₇H₃₇N₂⁺·Cl⁻·2CH₂Cl₂, the cation and the anion are each located on a crystallographic mirror plane. Both of the dichloro­methane solvent mol­ecules show a disorder across a mirror plane over two equally occupied positions. Additionally, one isopropyl group is also disordered. In the crystal, the cations are connected to the chloride ions via C—H...Cl hydrogen bonds.

1,3-Bis(2,6-diisopropyl­phen­yl)-1H-imidazol-3-ium bromide dichloro­methane disolvate

In the title compound, C₂₇H₃₇N₂⁺·Br⁻·2CH₂Cl₂, both the cation and the anion are located on a crystallographic mirror plane. Both of the dichloro­methane solvent mol­ecules show a disorder across a mirror plane over two equally occupied positions. In the crystal, the cations are connnected to the bromide ions via C—H...Br hydrogen bonds.

Butane-1,4-diyl bis­(pyridine-3-carboxyl­ate)

Mol­ecules of the title compound (alternative name: butane-1,4-diyl dinicotinate), C₁₆H₁₆N₂O₄, lie on a inversion centre, located at the mid-point of the central C—C bond of the aliphatic chain, giving one half-mol­ecule per asymmetric unit. The butane chain adopts an all-trans conformation. The dihedral angle between the mean plane of the butane-3-carboxyl­ate group [for the non-H atoms, maximum deviation = 0.0871 (15) Å] and the pyridine ring is 10.83 (7)°. In the crystal, mol­ecules lie in planes parallel to (122). The structure features weak π–π inter­actions with a centroid–centroid distance of 3.9281 (11) Å.

2,6-Diacetyl­pyridine–resorcinol (1/1)

The title co-crystal, C₉H₉NO₂·C₆H₆O₂, is composed of one 2,6-diacetyl­pyridine mol­ecule and one resorcinol mol­ecule as the asymmetric unit. In the 2,6-diacetyl­pyridine mol­ecule, the two carbonyl groups are anti­periplanar to the pyridine N atom. In the crystal, the 2,6-diacetyl­pyridine and resorcinol mol­ecules are connected by two O—H...O hydrogen bonds, forming planar chains of alternating components running along [120].

Intra- and inter­molecular proton transfer in 2,6-diamino­pyridinium 4-hy­droxy­pyridin-1-ium-2,6-dicarboxyl­ate

Chelidamic acid (4-hy­droxy­pyridine-2,6-dicarb­oxy­lic acid) and 2,6-diamino­pyridine react to form the title salt, C₅H₈N₃⁺·C₇H₄NO₅⁻; there are two formula units in the asymmetric unit. The pyridine N atom of 2,6-diamino­pyridine is protonated whereas chelidamic acid is deprotonated at both carboxyl­ate groups but protonated at the N atom; the reaction involves intra- and inter­molecular proton transfer. In the crystal, each 2,6-diamino­pyridinium cation participates in five strong N—H...O hydrogen bonds (including one bifurcated hydrogen bond). The crystal structure also features strong O—H...O hydrogen bonds between the chelidamate anions, leading to chains along the a axis.

rac-4-Chloro-2-[({2-[(3-chloro-6-hy­droxy-2,4-dimethyl­benz­yl)(meth­yl)amino]­prop­yl}(meth­yl)amino)­meth­yl]-3,5-dimethyl­phenol

The title compound, C₂₃H₃₂Cl₂N₂O₂, a potential chiral ligand for coordination chemistry, was prepared by a two-step reaction. The mol­ecule is located on a crystallographic centre of inversion. As a result, the methyl group bonded to the methyl­ene group is disordered over two equally occupied positions, sharing the same site as the H atom of the chiral C atom. As a further consequence of the crystallographic centrosymmetry, the 1,2-diamino­propane unit adopts an anti­periplanar conformation and the two benzene rings are coplanar. The central chain is in an all-trans arrangement. An intra­molecular O—H...N hydrogen bond makes an S(6) ring motif. A C—H...π inter­action links the mol­ecules into one-dimensional chains along the [001] direction.

Methyl 2-oxo-2H-chromene-3-carboxyl­ate

The title compound, C₁₁H₈O₄, features an almost planar mol­ecule (r.m.s. deviation = 0.033 Å for all non-H atoms). In the crystal, the mol­ecules are linked via C—H...O hydrogen bonds, forming two-dimensional networks lying parallel to (1-21).