N,N'-[1,4-Phenyl-enebis(imino-carbon-yl)]bis-(l-phenyl-alanine) tetra-hydro-furan disolvate.

The title compound, C26H26N4O6·2C4H8O, representing a bis-urea with terminal phenyl-alanine units, crystallized with two tetra-hydro-furan (THF) mol-ecules. The main mol-ecule is located on a crystallographic twofold axis, while the solvent mol-ecule is disordered over two positions, with occupancies of 0.571 (15) and 0.429 (15). The host mol-ecules are linked by N-H⋯O=C hydrogen bonds and C-H⋯O contacts with R 2 1(6) and R 2 1(7) ring motifs. The THF mol-ecules enclosed in the crystal are connected to the bis-urea compound via O-H⋯O and C-H⋯O inter-actions.

Formation of a macrocycle from di-chloro-dimethyl-silane and a pyridoxalimine Schiff base ligand.

The reaction of di-chloro-dimethyl-silane with a polydentate Schiff base ligand derived from pyridoxal and 2-ethano-lamine yielded the macrocyclic silicon compound (8E,22E)-4,4,12,18,18,26-hexa-methyl-3,5,17,19-tetra-oxa-8,13,22,27-tetra-aza-4,18-disilatri-cyclo-[22.4.0.010,15]octa-cosa-1(24),8,10,12,14,22,25,27-octa-ene-11,25-diol, C24H36N4O6Si2. The asymmetric unit contains the half macrocycle with an intra-molecular O-H⋯N hydrogen bond between the imine nitro-gen atom and a neighbouring oxygen atom. The crystal structure is dominated by C-H⋯O and C-H⋯π inter-actions, which form a high ordered mol-ecular network.

Crystal structure of 9,9-di-ethyl-9H-fluorene-2,4,7-tricarbaldehyde.

The title compound, C20H18O3, crystallizes in the space group P21/c with one mol-ecule in the asymmetric unit of the cell. The fluorene skeleton is nearly planar and the crystal structure is composed of mol-ecular layers extending parallel to the (302) plane. Within a layer, one formyl oxygen atom participates in the formation of a Carene-H⋯O bond, which is responsible for the formation of an inversion symmetric supra-molecular motif of graph set R 2 2(10). A second oxygen atom is involved in an intra-molecular Carene-H⋯O hydrogen bond and is further connected with a formyl hydrogen atom of an adjacent mol-ecule. A Hirshfeld surface analysis indicated that the most important contributions to the overall surface are from H⋯H (46.9%), O⋯H (27.9%) and C⋯H (17.8%) inter-actions.

Crystal structures of 2-[3,5-bis-(bromo-meth-yl)-2,4,6-tri-ethyl-benz-yl]isoindoline-1,3-dione and 2-{5-(bromo-meth-yl)-3-[(1,3-dioxoisoindolin-2-yl)meth-yl]-2,4,6-tri-ethyl-benz-yl}isoindoline-1,3-dione.

The title compounds, C23H25Br2NO2 (1) and C31H29BrN2O4 (2), crystallize in the space group P21/n with two (1-A and 1-B) and one mol-ecules, respectively, in the asymmetric unit of the cell. The mol-ecular conformation of these compounds is stabilized by intra-molecular C-H⋯O hydrogen bonds and C-H⋯N or C-H⋯π inter-actions. The crystal structure of 1 features a relatively strong Br⋯O=C halogen bond, which is not observed in the case of 2. Both crystal structures are characterized by the presence of C-H⋯Br hydrogen bonds and numerous inter-molecular C-H⋯O hydrogen-bonding inter-actions.

Bis-(triphenylphosphane) Aluminum Hydride: A Simple Way to Provide, Store, and Use Non-Polymerized Alane for Synthesis.

AlH3 (PPh3 )2 was synthesized as a stable solid being the first known 1 : 2 alane arylphosphane adduct. Although only weakly intra-molecularly coordinated, it displays as a molecular crystal significant inertness against atmospheric humidity and oxygen due to strong steric screening of the alane unit. The compound readily dissociates PPh3 in solution allowing for its use as a Lewis acidic reducing agent. These features lead to an easy to store, easy to use reducing agent that may enable the quantitative investigation of aluminum hydride chemistry including reduction, complexation and hydroalumination reactions. The structure contains two non-equivalent penta-coordinated aluminum centers that despite long Al-P distances of ca. 2.7 Šdisplay unusually high quadrupolar coupling constants CQ of 25.1 and 26.5 in 27 Al solid state NMR measurements. The product was also tested as a reducing agent on a small set of selected compounds with various functional groups.

Crystal structure of a methanol solvate of a macrocycle bearing two flexible side-arms.

Di-tert-butyl N,N'-{[13,15,28,30,31,33-hexa-ethyl-3,10,18,25,32,34-hexa-aza-penta-cyclo-[25.3.1.15,8.112,16.120,23]tetra-triaconta-1(31),3,5,7,9,12(33),13,15,18,20,22,24,27,29-tetra-deca-ene-14,29-di-yl]bis-(methyl-ene)}dicarbamate methanol disolvate, C52H72N8O4·2CH3OH, was found to crystallize in the space group P21/c with one half of the macrocycle (host) and one mol-ecule of solvent (guest) in the asymmetric unit of the cell, i.e. the host mol-ecule is located on a crystallographic symmetry center. Within the 1:2 host-guest complex, the solvent mol-ecules are accommodated in the host cavity and held in their positions by O-H⋯N and N-H⋯O bonds, thus forming ring synthons of graph set R 2 2(7). The connection of the 1:2 host-guest complexes is accomplished by C-H⋯O, C-H⋯N and C-H⋯π inter-actions, which create a three-dimensional supra-molecular network.

The heteroscorpionate ligand 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethanol and an easy preparation of its tungsten complex.

The heteroscorpionate ligand 2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethanol, C24H26N4O, features in the solid state an intramolecular O-H...N hydrogen bond. A heteroscorpionate tungsten complex, cis-[2,2-bis(3,5-dimethylpyrazolyl)-1,1-diphenylethanolato]chloridodioxidotungsten(VI) tetrahydrofuran monosolvate, [W(C24H25N4O)ClO2]·C4H8O, was prepared by the simple mixing of solutions of the ligand and WOCl4 in tetrahydrofuran. The tungsten complex was isolated after standing for several weeks. The complex exhibits a κ3N,N',O-coordination of the ligand. This simple synthetic procedure allows access to the cis isomer in high yield without additional purification steps. The Hirshfeld surface analysis shows a change of the intermolecular contacts due to the coordination of the WO2Cl unit with the ligand molecule.

Different supramolecular interactions mediated by Br atoms in the crystal structures of three anisole derivatives.

Three anisole building blocks featuring bis(hydroxymethyl) or bis(bromomethyl) pendants have been analyzed with regard to their molecular structures and packing behaviour. The compounds are ethyl 3,5-bis(hydroxymethyl)-4-methoxybenzoate, C12H16O5, (I), [5-bromo-3-(hydroxymethyl)-2-methoxyphenyl]methanol [or 4-bromo-2,6-bis(hydroxymethyl)anisole], C9H11BrO3, (II), and 5-bromo-1,3-bis(bromomethyl)-2-methoxybenzene [or 4-bromo-2,6-bis(bromomethyl)anisole], C9H9Br3O, (III). A typical supramolecular pattern involved C-H...π interactions generating molecular stacks, while π-π interactions were only observed in the absence of bromine, indicating a striking influence on the distances between adjacent aromatic moieties. When comparing bis(hydroxymethyl) compound (II) with bis(bromomethyl) compound (III), we found that the strong O-H...O hydrogen bonds in a zigzag arrangement in the first are replaced by C-H...Br interactions in the second without a change in the general packing.

Two reversible enantiotropic phase transitions in a pentacoordinate silicon complex with an O,N,O'-tridentate valinate ligand.

Dimethyl[N-(4-oxidopent-3-en-2-ylidene)valinato-κ(3)O,N,O']silicon(IV), C12H21NO3Si, (II), crystallizes in the orthorhombic space group P212121. The chiral compound undergoes two sharp enantiotropic phase transitions upon cooling. The first transformation occurs at 163 K to yield a unit cell with one axis having double length. This intermediate-temperature form has the monoclinic space group P21. The second transition takes place at 142 K and converts the single crystal into the low-temperature form in the orthorhombic space group P212121. This transition proceeds under tripling of the a axis of the high-temperature form. Both phase transitions are fully reversible and correspond to order-disorder transitions of the isopropyl group of the valine unit in the ligand backbone. The phase transitions presented here raise questions, since they do not fit into the rules of group-subgroup relationships.

Crystal structure of 4'-bromo-2,3,5,6-tetra-fluoro-biphenyl-4-carbo-nitrile.

The title compound, C13H4BrF4N, synthesized from 1,4'-bromo-iodo-benzene and 4-bromo-2,3,5,6-tetra-fluoro-benzo-nitrile in a coupling reaction was found to crystallize in the ortho-rhom-bic space group P212121. The two phenyl rings are rotated with respect to each other by 40.6 (6)°. The mol-ecules inter-act via aryl-perfluoroaryl stacking [3.796 (2) and 3.773 (2) Å], resulting in inter-molecular chains along the a-axis direction. C-H⋯F contacts of about 2.45 Šconnect these chains. In contrast to the structure of the parent compound 4'-bromo-biphenyl-4-carbo-nitrile, CN⋯Br contacts that could have given rise to a linear arrangement of the biphenyl mol-ecules desirable for non-linear optical (NLO) materials are not observed in the packing. Instead, several Br⋯F [3.2405 (17) and 3.2777 (18) Å] and F⋯F [2.894 (2) Å] contacts of side-on type II form an inter-molecular network of zigzag chains. The crystal studied was refined as an inversion twin.

5,8-Bis[bis-(pyridin-2-yl)amino]-1,3,4,6,7,9,9b-hepta-aza-phenalen-2(1H)-one dimethyl sulfoxide monosolvate dihydrate.

In the asymmetric unit of the title compound, C26H17N13O·C2H6OS·2H2O, there is one independent hepta-zine-based main mol-ecule, one dimethyl sulfoxide mol-ecule and two water mol-ecules as solvents. The tri-s-triazine unit is substituted with two dipyridyl amine moieties and a carbonylic O atom. As indicated by the bond lengths in this acid unit of the hepta-zine derivative [C=O = 1.213 (2) Å, while the adjacent C-N(H) bond = 1.405 (2) Å] it is best described by the keto form. The cyameluric nucleus is close to planar (r.m.s. deviation = 0.061 Å) and the pyridine rings are inclined to its mean plane by dihedral angles varying from 47.47 (5) to 70.22 (5)°. The host and guest mol-ecules are connected via N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds, forming a four-membered inversion dimer-like arrangement enclosing an R 4 (4)(24) ring motif. These arrangements stack along [1-10] with a weak π-π inter-action [inter-centroid distance = 3.8721 (12) Å] involving adjacent pyridine rings. There are also C-H⋯N and C-H⋯O hydrogen bonds and C-H⋯π inter-actions present within the host mol-ecule and linking inversion-related mol-ecules, forming a three-dimensional structure.

Photochemical dimerization of a fluorinated dibenzylideneacetone in chloroform solution.

(1E,4E)-1,5-Bis(2,6-difluorophenyl)penta-1,4-dien-3-one, C17H10F4O, (I), dimerizes under sunlight in chloroform solution to form the corresponding cyclobutane derivative, (2E,2'E)-1,1'-[2,4-bis(2,6-difluorophenyl)cyclobutane-1,3-diyl]bis[3-(2,6-difluorophenyl)prop-2-en-1-one], C34H20F8O2, (II). The crystal structure of (I) explains why no topochemical dimerization can occur in the solid state. In the solid, molecules of dimer (II) show the `truxillic acid'-type arrangement of crystallographic centres of inversion, with half a molecule per asymmetric unit and cell dimensions closely related to those of the monomer. Intermolecular interactions in both solids are dominated by C-H···O and C-H···F contacts and also comprise interactions with aromatic systems (C-H···π and π-π).

Enantiotropic phase transition in a binuclear tin complex with an O,N,O'-tridentate ligand.

The crystal structure of chlorido{µ-2-[(2-oxidobenzylidene)amino]ethanolato-κ(4)O,N,O':O'}{2-[(2-oxidobenzylidene)amino]ethanolato-κ(3)O,N,O'}trivinylditin(IV), [Sn2(C2H3)3(C9H9NO2)2Cl], is disordered above 178 K. A doubling of the unit-cell volume is observed on cooling. The asymmetric unit at 93 K contains two ordered molecules. The phase transition corresponds to an order-disorder transition of one vinyl group bound to the Sn(IV) atom.

Use of melem as a nucleophilic reagent to form the triphthalimide C6N7(phthal)3--new targets and prospects.

Melem (1), as one of the most important representatives of the tri-s-triazine compounds, can be used as a nucleophilic reagent in reactions with phthalic acid derivatives. The synthesis of 2,5,8-triphthalimido-tri-s-triazine (C(6)N(7)(phthal)(3), 2) was investigated starting from phthalic anhydride or phthalic dichloride in various solvents, at different temperatures as well as in the solid state. NMR measurements (solution and solid state), IR spectroscopy and elemental analysis indicated the formation of a cyclic imide. Single-crystal structure analysis of a 1:1 adduct of 2 with nitromethane proved the molecular structure expected for a phthalimido-s-heptazine. DFT calculations were performed to obtain a better insight into the structural features of compound 2, especially the interaction of the carbonyl groups with the tri-s-triazine nitrogen atoms. The title compound 2 shows promising properties: it is thermally stable up to 500 °C in air and shows strong photoluminescence with a maximum emission at around 500 nm. The potential of the nucleophilic reaction of melem with other strong electrophiles provides new targets and prospects.

Three new fluorinated N-phenyl-substituted pentacyclic ethanoanthracenedicarboximides.

Diels-Alder reaction between maleimides featuring 3,5-di-, 2,4,6-tri- and pentafluorinated N-phenyl substituents and anthracene yields the corresponding pentacyclic ethanoanthracenedicarboximide compounds, namely N-(3,5-difluorophenyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximide, C(24)H(15)F(2)NO(2), (IIa), N-(2,4,6-trifluorophenyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximide, C(24)H(14)F(3)NO(2), (IIb), N-(2,3,4,5,6-pentafluorophenyl)-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboximide, C(24)H(12)F(5)NO(2), (IIc). The crystal structures of (IIa)-(IIc) reveal an expected molecular geometry with a `V'-shape of the anthracene-derived tricyclic moiety. The crystal packings of (IIa) and (IIb) are dominated by π-π and C-H···O/F interactions, while F···F and C-H···π contacts are absent. In contrast, (IIc) shows F···F and C-H···O/F contacts, but no π-involved contacts of relevance.

1-Bromo-2,3,5,6-tetra-fluoro-4-nitro-benzene.

In the title compound, C(6)BrF(4)NO(2), the nitro group is twisted by 41.7 (3)° with reference to the arene ring mean plane. The main inter-actions stabilizing the crystal structure include O⋯Br contacts [3.150 (2) and 3.201 (2) Å], while F⋯F inter-actions are minor [2.863 (3)-2.908 (3) Å].

5,7-Dibromo-2-methyl-quinolin-8-ol.

In the title compound, C(10)H(7)Br(2)NO, the mol-ecule possesses a planar geometry with an r.m.s deviation of 0.0383 Šfor all non-H atoms. The crystal structure displays O-H⋯N and C-H⋯O hydrogen bonding, as well as Br⋯Br contacts [3.6284 (4) Å].

C(6)N(7)Cl[N(C(6)H(5))(2)](2).p-C(6)H(4)(CH(3))(2)-a mono-chloro-tri-s-triazine adduct.

We report the synthesis and comprehensive characterization including the first crystal structure of a disubstituted tri-s-triazine. The molecule bears one chlorine atom as a reactive site for further derivatisation.

(E)-1,3-Bis(2,3,4,5,6-penta-fluoro-phen-yl)prop-2-en-1-one.

In the title compound, C(15)H(2)F(10)O, the two perfluorinated arene rings are tilted at an angle of 66.08 (5)° with respect to each other. The olefinic double bond adopts an E configuration and the single bond between the olefinic and carbonyl double bonds has an s-trans conformation. The carbonyl group is not in a coplanar alignment with respect to the neighbouring arene ring (0.963 Šfrom aryl plane) while being coplanar with regard to the olefinic double bond (0.0805 Šfrom olefinic bond). The crystal packing does not feature significant hydrogen-bond-type or stacking inter-actions.

1,5-Bis(penta-fluoro-phen-yl)-3-phenyl-pent-2-ene-1,5-dione.

In the title compound, C(23)H(8)F(10)O(2), the three arene rings are twisted one with respect to the other: the two perfluorinated arene rings are tilted to each other by an angle of 60.39 (7)°. They are inclined to the non-fluorinated phenyl unit by 38.85 (7) and 78.74 (7)°. The olefinic double bond adopts an E configuration. The carbonyl groups are not in a coplanar alignment with reference to the neighbouring arene rings. The crystal packing features a number of weak C-H⋯F inter-actions, which leads to the formation of a three-dimensional network.