Crystallographic Mirror Plane Research Articles

Dipotassium biphenyl-4,4′-disulfonate dihydrate: a coordination polymer

The polymeric structure of the title compound, poly[[diaquabis(mu-biphenyl-4,4'-disulfonato)tetrapotassium(I)] dihydrate], [[K2(C12H8O6S2)(H2O)].H2O]n, is based on an asymmetric unit comprising three independent and different potassium centres, one six-coordinate [K-O, 2.657(3)-2.886(5)A, one seven-coordinate [K-O, 2.703(3)-3.040(4)A], and the third ten-coordinate [K-O, 2.751(3)-3.079(4)A], with two of these lying on crystallographic mirror planes. The four half-occupancy water molecules also lie on the mirror planes with two coordinated (one monodentate, the other bidentate bridging) and two as molecules of solvation. The interlinked coordination polyhedra form chains which are joined laterally through the biphenyl residues as well as through hydrogen-bonding interactions, giving a two-dimensional structure.

Triethynylphosphine oxide

In the solid state, the title compound, C6H3OP, lies on a crystallographic mirror plane, with the P=O as well as one of the acetyl­ene units bis­ected by this plane. The central P atom exhibits pseudo-tetra­hedral geometry. The crystallographic packing is dominated by C—H⋯O hydrogen bonds between all of the acetyl­ene H atoms and the O atom, which form a heavily inter­connected hydrogen-bonding network. Two of the hydrogen bonds, related by the mirror plane, are coplanar with each other and with the P=O unit, while the third C—H⋯O hydrogen bond is at an angle of 67.49 (7)° to this plane; the H⋯P=O angles are 134 and 112°, respectively. The three-dimensional structure formed by the hydrogen-bond inter­actions consists of two independent inter­penetrating networks.

2-(4-Fluorophenyl)-6-phenyltetrahydro-2H-thiopyran-4-one 1-oxide

In the title compound, C17H15FO2S, a crystallographic mirror plane bisects the molecule, passing through O=S and C=O of the central ring, with statistical disorder of the F atom. Orientational disorder of the aromatic ring is also observed; the site occupancy factors are ca. 0.75 and 0.25. In the molecule, the thiopyran unit has a chair conformation; the geometries around the S and carbonyl C atoms are tetrahedral and planar, respectively.

9-(Methoxymethyl)anthracene

The title compound, C16H14O, crystallizes with two independent molecules in the asymmetric unit, one of which lies on a crystallographic mirror plane. Intermolecular C—H...O hydrogen bonds link the molecules into infinite one-dimensional chains.

2-Hydroxypropane-1,3-diammonium bis(phosphonato)zincate(II) hemihydrate

In the title compound, (C3H12N2O)[Zn(HPO3)2]·0.5H2O, the inorganic macroanionic chain is built up from ZnO4 tetrahedra and HPO3 pseudo-pyramids sharing vertices. The organic dication shows positional disorder of its central –OH group in a 0.614 (7):0.386 (7) ratio. The components interact by way of O—H...O and N—H...O hydrogen bonds. The Zn atom lies on a crystallographic twofold axis and one C atom, the disordered O atoms of the –OH groups and the water O atom lie on a crystallographic mirror plane.

Quinoline derivatives: potential antiparasitic and antiviral agents

The crystal structures of closely related quinoline compounds substituted at the 2-position by a vinyl group, either including a Cl atom [2-(1-chloro-2-methylprop-1-enyl)-8-nitroquinoline, C(13)H(11)ClN(2)O(2), (I)] or not [2-(2-methylprop-1-enyl)-8-nitroquinoline, C(13)H(12)N(2)O(2), (II)], show an important deviation of the vinyl group from coplanarity with the quinoline ring system if the Cl atom is present. The nitro group is perpendicular [in (II)] or nearly so [in (I)] to the quinoline ring system. In (II), all non-H atoms except the nitro O atoms are located on a crystallographic mirror plane.

An unusualsynconformation of 5-formyluracil stabilized by supramolecular interactions

The asymmetric unit of the amino-oxo tautomer of 5-formyluracil (systematic name: 2,4-dioxo-1,2,3,4-tetrahydropyrimidine-5-carbaldehyde), C(5)H(4)N(2)O(3), comprises one planar amino-oxo tautomer, as every atom in the structure lies on a crystallographic mirror plane. At variance with all the previously reported small-molecule crystal structures containing the 5-formyluracil residue, the formyl substituent in the title compound exhibits an unusual syn conformation. The molecules are linked into planar sheets parallel to the bc plane by a combination of six N-H...O and C-H...O hydrogen bonds. Four of the hydrogen bonds are utilized to stabilize the formyl group in the syn conformation.

Catena-Poly[[silver(I)-μ-pyrazine-κ2 N:N′] perchlorate

In the title compound, [Ag(C4H4N2)]ClO4, pyrazine ligands bridge two symmetry-related Ag atoms [Ag—N = 2.222 (3) Å] to form linear polycationic chains which run along the c axis of the orthorhombic unit cell. The AgI ion has m2m site symmetry. The N atoms of the pyrazine ligand lie on a crystallographic mirror plane and each C atom of this ligand possesses crystallographically imposed disorder with two components of equal occupancy. The Cl atom of the perchlorate anion has m2m site symmetry and the two unique O atoms of this anion lie on a mirror plane. In addition, in the crystal structure, one-dimensional chains are linked through weak interactions involving perchlorate anions [Ag...O = 2.726 (2) Å] into a motif that can be described as a 4(4).6(2) sheet.

1-Bromo-4-nitro-2-(trifluoromethyl)benzene

The title compound, C7H3BrNO2, was synthesized by the nitration of 1-bromo-2-(trifluoromethyl)benzene. In the crystal structure, there are three independent molecules, one of which lies on a crystallographic mirror plane.

4,4′-Bipyridine–2,4,5,6-tetrafluoro-1,3-diiodobenzene (1/1)

The self-assembly of 1,3-diiodotetrafluorobenzene (13DITFB) and bipyridine (44BPY), C10H8N2·C6F4I2, is driven by halogen bonding. It results in infinite wave-like chains, with the two molecules in a 1:1 mole ratio. Both molecules lie on crystallographic mirror planes, bisecting the central 44BPY C—C bond and passing through two opposite CF groups of 13DITFB. The N...I halogen-bonding interaction is 2.902 (4) Å, and the C—I...N angle is almost linear [175.6 (2)°]. The chain ...13DITFB...44BPY... is polar, with all 13DITFB on the wave crest and all 44BPY at the bottom. This is in contrast to similar complexes obtained on self-assembly of 44BPY with 1,3-dibromotetrafluorobenzene (13DBrTFB), 1,4-diiodotetrafluorobenzene (14DITFB) or 1,2-diiodotetrafluorobenzene (12DITFB), where centrosymmetric wave-like chains are observed.

2-tert-Butyl 4-ethyl 3,5-dimethyl-1H-pyrrole-2,4-dicarboxylate

In the title compound, C14H21NO4, all the non-H atoms, except for one methyl C atom, lie on a crystallographic mirror plane. An N—H⋯O hydrogen bond helps to consolidate the crystal packing. A short intra­molecular C—H⋯O contact also occurs.

2-[2,6-Bis(4-methoxyphenyl)tetrahydrothiopyran-4-ylidene]malononitrile

In the title mol­ecule, C22H20N2O2S, the tetra­hydro­thio­pyran ring adopts a chair conformation. The dicyano­methyl­ene group and the 4-methoxy­phenyl groups have equatorial orientations. A crystallographic mirror plane bis­ects the mol­ecule, passing through the S and opposite C atoms of the central ring.

Crystal and molecular structures of the organometallic species [Rh2(bim)2(cod)2]Cl2∙2H2O [bim=bis-(1-imidazolyl)methane; cod=1, 5-cyclooctadiene

The synthesis and X-ray powder diffraction data for the organometallic [Rh2(bim)2(cod)2]Cl2∙2H2O species are reported. Its crystal and molecular structures were determined by simulated annealing and full-profile Rietveld refinement methods. [Rh2(bim)2(cod)2]Cl2∙2H2O was found to crystallize in the orthorhombic Cmca space group. The lattice parameters were determined to be a=21.3574(6), b=10.7764(3), c=14.2795(4) Å, V=3286.5(2) Å3, for Z=4. The crystal structure was found to contain dimeric [Rh2(bim)2(cod)2]2+ cations, in which the bim ligands bridge Rh(cod) fragments with an intermetallic separation of ca. 8.90 Å. The crystal structure is completed by chloride ions and hydrogen-bonded water molecules, situated in the small cavities of the large cation substructure. The conformation of the bim ligand, lying on a crystallographic mirror plane, is rigorously Cs.

N-(2-Bromo-1-phenylethyl)-4-methylbenzenesulfonamide

The title compound, C15H16BrNO2S, was obtained unintentionally in our work on the preparation of vicinal haloamine derivatives. The mol­ecule lies across a crystallographic mirror plane with the NH group disordered across this mirror plane. The dihedral angle between the benzene and phenyl rings is 25.10 (17)°. In the crystal structure, inter­molecular N—H⋯O hydrogen bonds link the mol­ecules into chains running along the b axis. In addition, C—H⋯Br hydrogen bonds are observed.

Tetra-μ3-bromido-tetrakis[trimethylplatinum(IV)

The title complex, [Pt4Br4(CH3)12], the tetra­mer of trimethyl­platinum(IV) bromide, reveals a distorted cubane-like structure and is disposed about a crystallographic mirror plane passing through two Pt atoms, two Br atoms and two methyl groups parallel to the ac plane. The tetra­meric complex displays pseudo-cubic mol­ecular symmetry, \overline{4}3m. The coordination geometry around each Pt centre is distorted octa­hedral. The tetra­meric units in the crystal structure are packed by hydro­phobic inter­actions or van der Waals contacts.

Polymeric KNOF2

The title compound, poly[μ-difluoridooxidonitrato-potassium], [KNOF2]n, crystallizes in the ortho­rhom­bic system and adopts the ordered KNO3 structure type. A crystallographic mirror plane passes through N, O and K. In the crystal structure, the polymer chains are linked by weak bonds into an infinite three-dimensional framework.

Cis-2,2-Dimethyl-1,3-diphenyl-2,3-dihydro-1H-benzo[c]silole

The title compound, C22H22Si, is a benzosilacyclo­pentene in which the silacyclo­pentene ring assumes an envelope conformation. The Si atom is displaced by 0.722 (4) Å from the mean plane of the four C atoms, and is bonded to two methyl groups and to two Csp3 atoms in the silacyclo­pentene ring. One phenyl ring is attached to each of these two C atoms in a cis configuration. The Si atom and the two methyl groups lie on a crystallographic mirror plane which relates the two halves of the molecule. The average Si—Cmeth­yl bond distance is 1.852 (3) Å. The Si—Csp3 bond distance is 1.886 (2) Å, and the corresponding Csp3—Si—Csp3 angle is 93.0 (1)°. The displacement ellipsoids for the atoms in the fused benzene ring suggest a probable disorder, but no satisfactory disorder model could be found.

3-(1,3-Dioxolan-2-yl)-6,7-dimethoxyquinoline

In the mol­ecule of the title compound, C14H15NO4, the quinoline ring system and meth­oxy substituents are located on a crystallographic mirror plane. The 1,3-dioxolane ring adopts an envelope conformation.

Mercuric cyanide as a receptor of pyrene

Cocrystallization of pyrene with Hg(CN)(2) gives a new clathrate, namely bis[dicyanidomercury(II)] pyrene solvate, [Hg(CN)(2)](2) x C(16)H(10), with molecules of pyrene embedded in cavities of the slightly deformed structure of the mercuric salt; the weak intermolecular N...Hg interactions present in pure Hg(CN)(2) are maintained in the cocrystal. The X-ray analysis of the resulting compound reveals unusual organic-inorganic interactions. One molecule of Hg(CN)(2) lies on a crystallographic mirror plane, while in the other, only the Hg atom is on the mirror plane. The molecule of pyrene is cut by a mirror plane perpendicular to the plane of the molecule.

Aqua{4,4′-dimethoxy-2,2′-[1,2-phenylenebis(nitrilomethylidyne)]diphenolato-κ4O,O′,N,N′}zinc(II)

In the title compound, [Zn(C22H18N2O4)(H2O)], the ZnII center, on a crystallographic mirror plane, is in a five-coordinate N2O3 environment that is approximately square pyramidal, with the N2O2 tetra­dentate Schiff base ligand as the basal plane and the water mol­ecule in the apical position. Inter­molecular O—H⋯O and weak C—H⋯O inter­actions link the mol­ecules into chains along [010]. These chains are further inter­connected in a zigzag manner into a three-dimensional network.