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International audience; Abstract A new tecton-like tetracarboxylic compound 1 featuring two isophthalic acid groups attached to both ends of a rigid 1,3-butadiyne spacer unit is synthesized using acetylene blocking/deblocking and coupling techniques. Crystallization of 1 from DMSO-chloroform solution gives rise to the formation of an unusual mixed solvent crystalline framework structure 1a containing DMSO and chloroform as secondary and tertiary components in 1:2:1 stoichiometric ratio. The X-ray crystal structure of 1a shows interesting stacking mode and hydrogen-bonded, three-dimensional network architecture with the two solvent species being involved in different behaviour pattern.

The bridge-substituted calix[4]arene carboxylic acid, 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetramethoxy-calix[4]arene-2-carboxylic acid (1), can be readily converted to various esters 2–4 and reduced to the alcohol 5, which reacts with methyl iodide to give the ether 6. The alcohol can be dansylated to give 7, the fluorescence of which is selectively quenched by Cu(II) in acetonitrile. An attempt to convert the acid 1 to an amide resulted unexpectedly in the formation of a lactone 8. The conformational characteristics of 1–8 have been studied in solution and, in the cases of 2 and 4, in the solid state by determination of their single-crystal X-ray structures. With the exception of 8, in all these compounds the bridge substituent adopts an equatorial (lateral) orientation.

In the title compound, C36H24Br3N3O6·C7H8, the toluene solvent molecule is associated with the receptor moleculeviaC—H...π bonding. The planes of the phthalimido groups are inclined at 77.0 (1), 63.0 (1) and 77.8 (1)° with respect to the benzene ring. The molecular conformation is stabilized by C—H...O and C—H...Br hydrogen bonds. The crystal structure features non-classical hydrogen bonds of the C—H...N, C—H...O and C—H...Br type, leading to a three-dimensional cross-linking of molecules. The pattern of non-covalent intermolecular bonding is completed by O...Br halogen bonds [3.306 (3) Å], which link the receptor molecules into infinite strands extending along thea-axis direction.

The title m-phenylene-bridged bis-oxazoles, C(36)H(24)N(2)O(2), (I), and C(52)H(56)N(2)O(2), (II), feature different aryl substituents in the 4- and 5-positions of the oxazole units. In the solid state, aside from the different twist of the peripheral aryl rings, the molecules show distinctly different conformations, with anti and syn orientations of the O and N atoms for (I) and (II), respectively. Connected with this property, in the crystal structure of (I), extensive π-stacking is found between the molecules, while the crystal structure of (II) only involves dimer formation as the prominent packing motif.

A series of tetraaryl-substituted cumulenes were synthesized and characterized by elemental analysis, 1H NMR, and MS spectra. Their inclusion capabilities for a variety of organic solvents were examined. It was found that substitution on the phenyl groups connected to both ends of these cumulenes critically influences their inclusion behavior since the substituents dictate the size and shape of lattice space for accommodation of the guest molecules. The crystal structures of an unsolvated butatriene and its 1 : 2 inclusion compounds with p-xylene and o-xylene were determined by X-ray crystallography. The structural analysis showed that the guest molecules do not simply fit into the free space of the host lattice, but their presence rearranges the packing mode of the host molecules in the inclusion compounds.

In the title solvated calixarene, C(47)H(60)O(4) x 2 CHCl(3), the host chalice displays an almost undistorted cone conformation, stabilized by three strong O-H...O hydrogen bonds at the calixarene's lower rim. One chloroform solvent molecule is fixed in the calixarene cavity by C-H...pi interactions, while the second is accommodated in a clathrate-like mode in elliptical packing voids. These voids are spanned by six host molecules connected via C-H...pi contacts and van der Waals interactions. Within the crystal structure, one tert-butyl group of the calixarene host is disordered over two orientations, with occupancies of 0.884 (4) and 0.116 (4). Furthermore, both solvent molecules show disorder, with occupancies of 0.857 (2) and 0.143 (2) for the cavitate-type, and 0.9359 (17) and 0.0641 (17) for the clathrate-type chloroform solvent molecules.

International audience; The new hydrazone ligand 1, featuring a 2-carboxy group at the aromatic ring and a trifluoromethyl structural modification in the pentane-2,4-dione moiety, has been synthesized via the Japp-Klingemann route. The compound is shown to form binuclear multicomponent chelate complexes (2 and 3) composed of two sodium ions, two charge equalizing carboxylates of the hydrazone molecule, two more carboxylic hydrazones and two alcoholic solvent molecules, with the latter being either EtOH or n-BuOH. X-ray crystal structures of the free hydrazone ligand as well as of the complexes have been studied. They demonstrate for the free ligand a ribbon-type aggregation of carboxylic dimers, while the isomorphous complexes possess a remarkable binuclear structure with the two sodium ions in an distorted octahedral coordination geometry of six oxygen atoms coming, as the equatorial and apical sites, from the hydrazone carbonyl groups and the hydroxyl of the solvent molecules, respectively. Hydrogen bonds owing to the alcohol molecules give rise to stack formation of the supramolecular cluster. Weak intermolecular contacts involving the fluorine atoms are also contributing to the crystalline packing both in the case of the free ligand and the complexes.

The X-ray crystallographic structures of four new inclusion compounds of the versatile clathrate host 2,2'-bis(9-hydroxy-9-fluorenyl)biphenyl (1) as well as the crystal structure of the unsolvated host are reported and comparatively discussed with regard to the molecular conformation and the modes of interactions the molecules make use of in the crystal packing. While the inclusion crystals demonstrate full saturation of the hydrogen bond capacity of the host molecule, 1 is only involved in weak intermolecular pi-contacts in the solvent-free structure. We draw the conclusion that the well-tried strategy of coordinatoclathration, underlying the present inclusion compounds, should not be regarded as a strict rule with reference to the formation of inclusion crystals but it helpful framework in the search of new efficient clathrate hosts. Crystal Growth & Design

In the title compound, C55H69BrO4, the calixarene molecule displays a `partial cone' conformation bearing the lateral substituent in a sterically favorable equatorial arrangement between two syn-orientated arene units. The crystal packing is stabilized by weak C—H...π contacts, involving one tert-butyl group, and π–stacking interactions of the lateral bromobenzene units [centroid–centroid distance = 3.706 (1) Å].

The interaction of Cu(II) with the following secondary N-substituted derivatives of di(2-picolyl)amine () are reported: N-cyclohexylmethyl-di(2-picolyl)amine (), N-benzyl-di(2-picolyl)amine (), N-(4-pyridylmethyl)-di(2-picolyl)amine (), N-(4-carboxymethylbenzyl)-di(2-picolyl)amine (), N-(9-anthracen-8-ylmethyl)-di(2-picolyl)amine (), 1,3-bis[di(2-picolyl)aminomethyl]benzene (), 1,4-bis[di(2-picolyl)aminomethyl]benzene () and 2,4,6-tris[di(2-picolyl)amino]triazine (). The solid complexes [Cu()(micro-Cl)](2)(PF(6))(2), [Cu()(micro-Cl)](2)(PF(6))(2).0.5CH(2)Cl(2), Cu()(ClO(4))(2), Cu()(2)(ClO(4))(2), [Cu()(ClO(4))(2)(H(2)O)].0.5H(2)O, Cu(2)()(ClO(4))(4), [Cu(2)()(Cl)(4)] and [Cu(2)(+H)(micro-OCH(3))(2)(H(2)O)](ClO(4))(3).C(4)H(10)O were isolated and X-ray structures of [Cu()(micro-Cl)](2)(PF(6))(2), [Cu()(micro-Cl)](2)(PF(6))(2).0.5CH(2)Cl(2,) [Cu()(2)(ClO(4))(2)(H(2)O)].0.5H(2)O, [Cu(2)()Cl(4)] and [Cu(2)(+H)(micro-OCH(3))(2)(H(2)O)](ClO(4))(3).C(4)H(10)O were obtained. The series is characterised by a varied range of coordination geometries and lattice architectures which in the case of [Cu()(ClO(4))(2)(H(2)O)].0.5H(2)O includes a chain-like structure formed by unusual intermolecular pi-interactions between metal bound perchlorate anions and the aromatic rings of adjacent anthracenyl groups. Variable temperature magnetic susceptibility measurements have been performed for [Cu()(micro-Cl)](2)(PF(6))(2) and [Cu()(micro-Cl)](2)(PF(6))(2).0.5H(2)O over the range 2-300 K. Both compounds show Curie-Weiss behaviour, with the data indicating weak antiferromagnetic interaction between the pairs of copper ions in each complex. Liquid-liquid (H(2)O/CHCl(3)) extraction experiments involving and as extractants showed that, relative to the parent (unsubstituted) dipic ligand , substitution at the secondary amine site in each case resulted in an increase in extraction efficiency towards Cu(II) (as its perchlorate salt); at least in part, this increase may be attributed to the enhanced lipophilicities of the N-substituted derivatives.

An ethynylene diisophthalic acid linker molecule was synthesized and used to form a zinc carboxylate-based metal organic framework (MOF) with very large pores and unit cell volume resulting from the unusual combination of structurally different inorganic units forming the secondary building blocks (SBUs). The structure is the first zinc hydroxide carboxylate structure where the inorganic units do not form layers or ribbons but isolated islands. The structure forms true pores with a significantly narrowed pore entry similar to zeolites. The pores are, thus, not created simply by intersecting channels as in most other MOF structures. Although the pore shape is highly asymmetric the spherical free volume is with 10.8 A still large. The stability of the SBUs in respect to exchange and removal of coordinated solvent molecules is investigated.

Allene dimers of the 1,2-dimethylenecyclobutane-type with bridged aromatic groups (fluorenylidene units) and extra substituents (Me,t-Bu)2a-c have been synthesized and characterized by elemental analysis and spectroscopic data. Their crystal inclusion properties are reported. The unsubstituted compound2a yields only an inclusion compound withp-xylene, while methyl-substituted2b enclathrates a broad range of molecules. On the other hand, thet-butyl-substituted2c does not form clathrates, crystallizing as a pure compound. Complete structural descriptions of the two inclusion compounds2a-p-xylene (2:1) and2b-phenyloxirane (1:1) are given. They represent interstitial clathrates. Crystallographic data of the 1:1p-xylene clathrate of2b (which is isomorphous to its phenyloxirane analog) and of unsolvated2c are also reported. As indicated by the results, substitutional effects critically influence the inclusion properties of the new clathrate family.

A series of tetraaryl-substituted cumulenes were synthesized and characterized by elemental analysis, 1H NMR, and MS spectra. Their inclusion capabilities for a variety of organic solvents were examined. It was found that substitution on the phenyl groups connected to both ends of these cumulenes critically influences their inclusion behavior since the substituents dictate the size and shape of lattice space for accommodation of the guest molecules. The crystal structures of an unsolvated butatriene and its 1 : 2 inclusion compounds with p-xylene and o-xylene were determined by X-ray crystallography. The structural analysis showed that the guest molecules do not simply fit into the free space of the host lattice, but their presence rearranges the packing mode of the host molecules in the inclusion compounds.

International audience; The synthesis and crystal structures of a calix[4]arene (1) with two affixed pyrene units and its corresponding inclusion compound with chloroform (1a) are reported. In both cases, stacking structures resulting from the influencing control of the pyrene units are observed. Dependent on the absence or presence of the included guest solvent, infinite or dimeric stack motifs of the pyrene units are concerned, respectively.

In the crystal structure of the title compound, C(12)H(12)N(2), the mol-ecule is twisted around the central C-C bond, with a dihedral angle of 8.32 (5)° between the mean planes of the pyridyl rings. The crystal structure is stabilized by arene stacking inter-actions, with a distance of 3.81 (1) Å between the ring centroids.

In the title compound, C48H64O4·0.5CH2Cl2, both crystallographically independent calixarene molecules display a partial cone conformation. Their crystal packing is stabilized by C—H...π contacts involving the methoxy groups. The solvent molecule is located interstitially between two calixarene units with C—H...Cl contacts to methoxy and tert-butyl groups. One tert-butyl residue of each calixarene molecule is disordered over two positions (occupancies 0.60/0.40 and 0.63/0.37), resulting in bond distances that deviate from ideal values. The tetramer calixarene molecules present models with approximate non-crystallographic Cs symmetry.

Clathrate Formers with Allene Structure – Host Compounds, Crystal Inclusion, and Structure of a Dioxane Clathrate The tetraaryl-substituted allenes 1–8 are synthesized, and their properties in crystal inclusion are determined. Dependent on the type and number of the substituents, host compounds result, which have different inclusion properties and clathrate selectivities. Host 1h forms inclusion compounds with a wide range of apolar and relatively polar cyclic guest solvents (26 inclusions altogether), while 2, 4, 5, and 7b form only one or two inclusions. In two-component solvent systems, high inclusion selectivities are found for the host compounds. The crystal structure of the 4.dioxane (1:1) clathrate is reported. Relations between structure and inclusion selectivity are discussed.

A basic aluminium chloride with high chlorine content (basicity 1.85) has been crystallized from a concentrated aqueous solution. Its crystal structure has been determined by X-ray structure analysis. The structure contains tridecameric cations of a novel type consisting only of interconnected AlO6 octahedra. The formation of these polycations is discussed.

The asymmetric unit of the title compound, C44H30O2, contains two independent mol-ecules in which the terminal rings of the terphenyl element are inclined at angles of 36.3 (1) and 22.5 (1)° with respect to the central ring and the dihedral angles between the fluorenyl units are 72.3 (1) and 62.8 (1)°. In the crystal, pairs of O-H⋯O hydrogen bonds link the mol-ecules into inversion dimers. The hy-droxy H atoms not involved in these hydrogen bonds form O-H⋯π inter-actions in which the central terphenyl rings act as acceptors. Weak C-H⋯O contacts and π-π [centroid-centroid distance = 4.088 (2) Å] stacking inter-actions also occur. Taking into account directed non-covalent bonding between the molecules, the crystal is constructed of supramolecular strands extending along the a-axis direction.

In the title compound, C11H5I2N, the two iodine-atom substitutents with their large atomic sizes lead to short intra­molecular I⋯H distances (3.01 Å). In the crystal, the tris­ubstituted azulene system forms π-stacks [centroid–centroid distance = 3.6343 (11) Å] along the a-axis direction, showing the characteristic azulene inter­action mode between the electron-rich five-membered ring and the electron-deficient seven-membered ring. I⋯I [3.9129 (2) Å] non-covalent contacts are observed along with weak C—H⋯N and C—H⋯π. bonds.

X-ray data on the crystal and molecular structure of bis(biphenyl-2,2′-diyl)allene, reveal a remarkably strong deviation from linearity (170·1°) of the allene unit of the molecule. Ab initio calculations involving dimers of molecules yield good correlation with this geometry, showing that the non-linearity is due to packing effects in the crystal.

Seven new hexahelicenes (3−7, 9, 10) containing different functional group substituents have been synthesized and, in three cases (4, 8, 10), optically resolved. Optical rotations were measured and CD spectra are reported. X-ray crystal structures of the helicenes 1, 3, 4, 8, and 9 have been determined, of which 4 represents a 1:1 clathrate with acetone. These show a concerted interplay of C−H···O, C−H···π, and π···π supramolecular interactions in the packings, mostly yielding stacks of molecules (1, 3, 4, 8). Statistical analysis of the molecular dimensions in these and related crystal structures was carried out in order to identify potential parameters relevant to macroscopic phenomena, including optical rotation. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

The title compound, [Ni{N(CH(2)CH(2)OH)(3)}(2)](CH(3)COO)(2), was prepared and the structure determined. It is isostructural with the copper(II) analogue.

'3+1' Oxorhenium(v) complexes [ReO(SN(R')S)(SR)] (R' = Me, Et, Pr or Bu; SR = aminoalkane thiolate) have been synthesized by ligand exchange at trans-trichloromonooxo-bis(triphenylphosphine)rhenium(v) with a mixture of HSN(R')SH and RSH in alkaline methanolic solution. The complexes were purified by column chromatography and characterized by elemental analysis, mass and IR spectroscopy and for selected compounds by 1H NMR spectroscopy. The structures of those complexes have been determined by X-ray diffraction analysis and revealed a change in the co-ordination geometry from square pyramidal to trigonal bipyramidal, depending on the chelating (SN(R')S) moiety. The alkyl group (R') was found to be arranged "syn" to the oxorhenium group.

The asymmetric unit of the title compound, C44H64O4·C4H8O, comprises two crystallographically independent calixarene mol-ecules, which display a partial cone conformation, and two tetrahydrofuran molecules. The crystal packing is stabilized by C - H⋯π contacts involving the meth-oxy groups, while the solvent mol-ecules are located in voids between the calixarene molecules. Two of the tert-butyl residues of each calixarene mol-ecule are disordered over two positions [0.74/0.26 (ring B), 0.71/0.29 (ring C), 0.77/0.23 (ring C′), 0.67/0.33 (ring D′)], resulting in bond distances that deviate from ideal values.

The crystal structure of the title compound, C22H41NO6, is stabilized by inter­molecular N—H⋯O hydrogen-bonding contacts.

The title compound, C18H14O, crystallizes with aromatic �–� stacking interactions.

The title mol­ecule, C36H27N3O9, adopts an almost symmetric conformation in which the mean planes of the phthalimido units are inclined at dihedral angles of 81.1 (1), 85.3 (1) and 86.3 (1)° with respect to the plane of the central aromatic ring. The O atoms are involved in intra- and inter­molecular C—H⋯O hydrogen bonding. The crystal structure also features π–π arene inter­actions [minimum ring centroid separation = 3.683 (2) Å]. The present mode of non-covalent interactions leads to a three-dimensional supramolecular architecture.

There are three independent mol-ecules in the asymmetric unit of the title compound, C12H15Br3O3, two of which have approximate trigonal symmetry, the third being conformationally different as it adopts near mirror symmetry. The crystal structure features C-H⋯Br inter-actions, a weak C-H⋯O hydrogen bond, π-π inter-actions [minimum ring centroid separation = 3.4927 (18) Å] and a short Br⋯Br contact [3.5894 (5) Å], resulting in a three-dimensional supramolecular network.

C31H20O, monoclinic, P121/n1 (No. 14), a = 11.588(2) Å, b = 12.306(2) Å, c = 15.794(3) Å, β = 105.65(3)°, V = 2168.8 Å3, Z = 4, Rgt(F) = 0.071, wRref(F2) = 0.203, T = 298 K.

The asymmetric unit of the title compound, C24H26S2, consits of one half-molecule, which is located on a center of inversion. The two benzene rings are exactly coplanar while the tert-butyl group is oriented nearly perpendicular to the ring plane [C—S—C—C = −81.14 (11)°].

In the title compound, C14H8Br2N2O2, the molecular structure features intramolecular N—H...O [2.639 (2) Å and 130°] and N—H...Br [3.053 (2) Å and 114°] hydrogen bonding. Due to inversion symmetry, the asymmetric part of the unit cell consits of one half-molecule. In the crystal, inversion dimers linked by pairs of N—H...O [2.955 (2) Å and 135°] hydrogen bonds occur. The structure also features C=O...π [3.228 (2) Å] and Br...Br [3.569 (1) Å] contacts.

The new 1,3,5-tri-substituted and hexa-substituted benzoic methyl esters 1, 3 and benzoic acids 2, 4 have been synthesized. Single-crystal structure determinations of 1 - 3 are reported, which show specific molecular conformations and packings in the crystal. In all structures, the conformation of the molecules deviates considerably from threefold and sixfold symmetry, respectively. Columnar packings are observed in the crystal structures of the esters 1 and 3, stabilized by weak C-H・・・O and C-H・・・π interactions, while the packing of 2 features the formation of supramolecular strands involving the dimerization of the carboxylic acid group.

The bisoxazoles 1a - 1c that feature structures with two oxazole moieties connected to a 2,6- pyridylene central linker and contain different aryl substituents in 4- and 5-positions of the oxazole rings have been synthesized. Single-crystal X-ray structure determinations of the free ligand 1a, containing the NiCl2 complex of 1c as the CH3COOH solvate as well as the 1,4-dioxane-solvated diester intermediate 2a are reported, which show specific molecular conformations and packings in the crystals. The conformation of 1a is syn with reference to the oxazole nitrogen atoms and anti with reference to the oxazole and pyridine nitrogen atoms. In the Ni2+ complex, the metal ion is in an octahedral coordination environment with the nitrogens of 1c and an oxygen of an acetic acid molecule in the basal plane, while two chloride ions occupy the axial positions of three additional acetic acid molecules one is hydrogen-bonded to a chloride and two form a carboxylic dimer, thus giving rise to a 1 : 1 : 4 (1c: NiCl2 :HOAc) stoichiometric ratio. The crystalline 1 : 1 inclusion compound of 2a with 1,4-dioxane suggests a typical clathrate owing to the bulkyness of the host molecule.

Performing a standard Japp-Klingemann synthesis that involved diazotation of 2,6-dinitroaniline and reaction with pentane-2,4-dione in aqueous hydrochloric acid medium surprisingly yielded a mixture of the expected 2,6-dinitro- and the unexpected 2-chloro-6-nitro-substituted hydrazones. This mixture was isolated as solid-solution crystals containing the components in an approximate ratio of 1 to 2. Based on both, selected compounds of comparison that show the aromatic ring substituents changed in position and intermediate diazonium salts, potential causal connections of the unusual behaviour during the route of the particular Japp-Klingemann reaction were studied. X-Ray crystal structures of the relevant compounds have been determined to support the discussion.

A detailed conformational analysis of a rarely investigated type of compound, a laterally monosubstituted calix[4]arene (1, which has a carboxylic acid function in the lateral position), is reported. 2D solution NMR techniques at various temperatures and in different solvents have been used, showing interesting aggregation behaviour for the different conformers. The first illustrations of crystal structures of this compound type are given, including the unsolvated carboxylic calix[4]arene and two mixed solvent complexes containing EtOH–H2O and EtOH–THF, respectively. Isostructurality calculations have been carried out, allowing detailed comparison of the investigated structures, and an unusual conformational chirality isomerism of the calixarene molecule is demonstrated.

Four new betaine dyes of the Reichardt's type featuring two tolyl substituents in different attachment (2–4) or being an analogous 1-naphthyl derivative (5) have been synthesized and described with reference to their negative solvatochromism. The dinaphthyl derivative 5 and also a corresponding intermediate nitrophenol 9d were shown with variable-temperature NMR spectroscopy to form conformational atropisomers in solution. Crystal structures of seven alcoholic solvent complexes including the unsubstituted parent compound (1) and different alcohols [1·EtOH (1:1), 1·i-PrOH (1:1), 2·MeOH (1:2), 3·i-PrOH (1:1), 3·n-BuOH (1:1), 4·EtOH (1:2) and 5·MeOH (1:3)] have been studied using X-ray diffraction methods. The betaine dyes exist as genuine zwitterion ground state structures in the solid state with twisted conformation between the phenoxide and pyridinium rings. With the exception of 3a [3·i-PrOH (1:1)], the alcohol guests in the complexes are hydrogen bonded to the oxygen atom of the phenoxide units, whereas in the i-PrOH complex of 3, the alcohol forms trimeric clusters without specific interaction with the betaine framework. From the packing modes in the crystals, the solvated betaines may be classified either as co-ordination type inclusion compounds with pocket-like host arrangements [1·EtOH (1:1), 1·i-PrOH (1:1), 2·MeOH (1:2), 3·n-BuOH (1:1), 4·EtOH (1:2) and 5·MeOH (1:3)], or a true clathrate with channel-type topology [3·i-PrOH (1:1)].

In order to find out the consequences of a phenyl for pyridyl exchange on the crystalline packing behaviour of the parent compound 9-phenyl-9-fluorenol, three analogous 9-pyridyl substituted 9-fluorenols featuring the pyridyl ring in different linkage positions were comparatively studied with regard to their crystal structures. While the molecular structures in the crystal are not noticeably altered, the network structures are, showing the leading influence of the nitrogen atom to cause a variation of contact modes. Corresponding to the substitution site of the pyridyl group, these involve intra- and intermolecular hydrogen bonds, including helical and linear strand formation.

A series of new fluorescent calix[4]arenes (2-7; 5 has been isolated as two not yet described conformational isomers) featuring two directly lower rim attached dansyl moieties besides other lower or upper rim site substituents have been synthesized and investigated with reference to their fluorescence properties including potential sensing capability for metal ions. Except for the nitro substituted compound 7, which showed a moderate fluorescence quenching on the addition of Hg2+ in acetonitrile, the calixarenes 2-6 were found to selectively recognize Cu2+ in the 10(-6) mol L(-1) concentration range detectable by the nearly total quenching of their intrinsic fluorescence. Using fluorescence titration experiments, the ideal complexation ratio [metal ion]/[ligand] for three exemplarily investigated calixarenes (3, 5a and 7) was determined to be 2:1. For 5a, a new red shifted signal was observed by the complexation of Cu2+ while the addition of Hg2+ only yields a moderate quenching of the parent signal, indicating a different binding mode for both metal ions. This finding enables the calixarene 5a to be used as a suitable chemosensor for the simultaneous determination of copper and mercury. In this paper we also present the first crystal structures of dansylated calixarenes having the dansyl groups directly attached to the lower rim site. They involve the unsolvated calixarene 5b and the two solvent inclusion compounds 2.CH2(OH)CN and 3.3CH3CN, each showing an extensive pattern of non-covalent interactions. In both solvates, the calixarenes are fixed in a cone conformation while the unsolvated calixarene 5b adopts the partial cone conformation. A solution 1H NMR study in CDCl3 reveals also the cone conformation for all dansylated calixarenes, except the more conformationally flexible upper rim unsubstituted calixarene 5 which showed cone and partial cone conformers 5a and 5b, respectively, in an approximate 2:3 ratio.

In the title compound (systematic name: 17-formyl-2,5,8,11,14-penta­oxabicyclo­[13.4.0]nona­deca-15,17,19-triene), C15H20O6, the 15-crown-5 ring adopts a twisted conformation. The formyl group is coplanar with the benzene ring. The crystal packing is stabilized by C—H⋯O inter­actions involving the C=O group and ether O atoms as acceptors and methyl­ene CH groups as donors.

Three new hydrazone compounds having a p-iodoaryl and diketohydrazone molecular skeleton in common but feature a gradual replacement of the two methyl groups for trifluoromethyl terminal ones were prepared and comparatively studied with regard to their crystal structures. A quantum chemical calculation of the single trifluoromethyl modified compound was undertaken to decide on the hydrogen bonded ring site. While the molecular structures of the compounds remain rather unimpaired by the fluorine substitution, their crystalline packings are markedly affected, showing a distinct supramolecular control in the crystal lattices.

Based on the principle of supramolecular preorganization, a new type of oligofunctional amphiphile, of which compounds 1-4 are representative structures, has been designed and synthesized. The typical feature of their structure is a highly rigid and geometrically well-defined central unit composed of ethynylene substituted aromatic spacers with different numbers of amphiphilic segment groups (also of a rigid geometric design) attached to it. The molecules form well-defined Langmuir films when spread from a solution at the air/water interface or when a 10(-4) M aqueous CaCl2 solution was used as the subphase. By analysis of the surface pressure-surface area (pi-A) isotherms, information on the packing behavior and orientation of the amphiphilic molecules depending on the molecular structure could be obtained. Morphological characterization of the dynamic process of monolayer compression at the air/water interface was carried out by Brewster angle microscopy, illustrating several phase states visualized as snap shots. Thin monolayer films produced on a 10(-4) M aqueous CaCl2 subphase can be transferred to a mica solid support by the Langmuir-Blodgett technique. Tapping mode atomic force microscopy reveals a surface topography of the monofilms composed of 1 and 3 that differ in roughness and also in the properties of elasticity, hardness and adhesive strength. X-Ray crystal structure analysis of three relevant intermediate compounds of the synthesis were successfully determined giving an indication of the potential structural features inherent in the new amphiphiles.

Crystal structures of three fluorinated benzophenones were determined via single crystal X-ray diffraction. The occurrence of the C–F⋯H, F⋯F, C–F⋯πF interactions in these crystal structures indicates that a base limit of fluorine atoms in the molecule seems to be necessary for successful competition with the hydrogen type of interactions.