The effect of specific solvent-solute interactions on complexation of alkali-metal cations by a lower-rim calix[4]arene amide derivative.

Complexation of alkali-metal cations with calix[4]arene secondary-amide derivative, 5,11,17,23-tetra(tert-butyl)-25,26,27,28-tetra(N-hexylcarbamoylmethoxy)calix[4]arene (L), in benzonitrile (PhCN) and methanol (MeOH) was studied by means of microcalorimetry, UV and NMR spectroscopies, and in the solid state by X-ray crystallography. The inclusion of solvent molecules (including acetonitrile, MeCN) in the calixarene hydrophobic cavity was also investigated. The classical molecular dynamics (MD) simulations of the systems studied were carried out.

Solvent-free Mechanosynthesis of Two Thermochromic Schiff Bases.

Two thermochromic Schiff bases mostly in keto-amine tautomeric form were obtained by means of mechanochemical synthesis. Both Schiff bases Compound 1 and Compound 2, respectively are derived from the same primary amine 2-amino-5-methylphenol. Salicylaldehyde was used as aldehyde component in preparation of 1, and o-vanillin as substituted salicylaldehyde component in synthesis of 2.

Effect of atmosphere on solid-state amine-aldehyde condensations: gas-phase catalysts for solid-state transformations.

The presence of water or organic solvent vapour accelerates the solid-state condensation of solid aromatic amines and aromatic aldehydes into Schiff bases; we show the important role of catalytic triethylamine in the vapour phase in such vapour digestion synthesis, as well as in the liquid phase in synthesis via liquid-assisted grinding.

An Integrated approach (thermodynamic, structural, and computational) to the study of complexation of alkali-metal cations by a lower-rim calix[4]arene amide derivative in acetonitrile.

The calix[4]arene secondary-amide derivative L was synthesized, and its complexation with alkali-metal cations in acetonitrile (MeCN) was studied by means of spectrophotometric, NMR, conductometric, and microcalorimetric titrations at 25 °C. The stability constants of the 1:1 (metal/ligand) complexes determined by different methods were in excellent agreement. For the complexation of M(+) (M = Li, Na, K) with L, both enthalpic and entropic contributions were favorable, with their values and mutual relations being quite strongly dependent on the cation.

1-[(4-{[(2-Oxo-1,2-dihydro-naphthalen-1-yl-idene)meth-yl]amino}-anilino)methyl-idene]naphthalen-2(1H)-one dihydrate.

The title compound, C(28)H(20)N(2)O(2)·2H(2)O, comprises a Schiff base mol-ecule with an imposed inversion centre in the middle of p-phenyl-enediamine unit and water mol-ecules of crystallization. In the structure, the Schiff base mol-ecule is present as the keto-amino tautomer with a strong intra-molecular N-H⋯O hydrogen bond. The Schiff base mol-ecules and water mol-ecules of crystallization create infinite [010] columns through O-H⋯O hydrogen bonds.

1,1'-[m-Phenyl-enebis(nitrilo-methanylyl-idene)]dinaphthalen-2-ol-1,1'-[m-phenyl-enebis(imino-methanylyl-idene)]dinaphthalen-2(1H)-one (0.58/0.42).

In the solid state the title Schiff base, 0.58C(28)H(20)N(2)O(2)·0.42C(28)H(20)N(2)O(2), exists both as the keto-imino and as the enol-amino tautomer, which is manifested in the disorder of the H atom in the intra-molecular hydrogen-bonded ring.

2-{[(4-{[(2-Hy-droxy-phen-yl)(phen-yl)methyl-idene]amino}-phen-yl)imino](phen-yl)meth-yl}phenol.

The title mol-ecule, C(32)H(24)N(2)O(2), has a crystallographically imposed inversion centre and exists in the crystal as an enol-imine tautomer. The mol-ecular structure is stabilized by two strong intra-molecular O-H⋯N hydrogen bonds. The dihedral angles between the central benzene ring and the mean planes of the phenyl substituents are 59.

Two Ketimine Polymorphs of 2-{1-[(2-Aminophenyl)imino]ethyl}phenol.

Two polymorphic structures of the Schiff base 2-1-[(2-aminophenyl)imino]ethylphenol, compound (1), C14H14N2O are reported. Depending on the solvent used for recrystallization it crystallizes as either a monoclinic or an orthorhombic polymorph. The monoclinic form, polymorph [1] contains three, while the orthorhombic polymorph [2] contains only one molecule in the asymmetric unit.

2,2'-[1,5-Bis(4-amino-phen-yl)-1,5-dihydro-benzo[1,2-d;4,5-d']diimidazole-2,6-di-yl]diphenol.

The title mol-ecule, C(32)H(24)N(6)O(2), has a crystallographic inversion centre in the middle of the benzodiimidazole core. It exists as the enol-imine tautomeric form and exhibits a strong intra-molecular O-H⋯N hydrogen bond. The dihedral angles between the planes of the 2-hy-droxy-phenyl and 4-amino-phenyl substituents and the plane of the benzodiimidazole unit [12.

2-[1-(3-Amino-phenyl-imino)-eth-yl]phenol.

The title compound, C(14)H(14)N(2)O, exists as the enol-imine tautomer. A strong intra-molecular hydrogen bond between O and N atoms forms a six-membered ring with an S(6) graph-set motif, which is approximately coplanar with the phenol ring, the inter-planar angle being 3.4 (3)°.

Comparative refinement of correct and incorrect structural models of tetrabutylammonium tetrabutylborate - pitfalls arising from poor-quality data.

This paper demonstrates how numerical parameters usually used to assess the quality of a crystal structure solution (R, wR and S) may be misleading when studying a model refined against poor-quality data. Weakly diffracting crystals of tetrabutylammonium tetrabutylborate, a low-density organic salt comprising isoelectronic cations and anions, were measured using Cu and Mo Kalpha radiation. Along with the correct structural model, six erroneous structural models were constructed and refined against the same data.

(R,S)-3-Carb-oxy-2-(isoquinolinium-2-yl)propanoate monohydrate.

The title compound, C(13)H(11)NO(4)·H(2)O, is a monohydrate of a betaine exhibiting a positively charged N-substituted isoquino-line group and a deprotonated carboxyl group. In the crystal, mol-ecules are connected via short O-H⋯O hydrogen bonds between protonated and deprotonated carboxyl groups into chains of either R or S enanti-omers along [001]. These chains are additionally connected by hydrogen bonding between water mol-ecules and the deprotonated carb-oxy groups of neighbouring mol-ecules.

Interactions between dimers of {1,1'-[o-phenylenebis(nitrilomethylidyne)]di-2-naphtholato-kappa4O,N,N',O'}nickel(II).

In the title compound, [Ni(C(28)H(18)N(2)O(2))], the Ni(II) centre has a square-planar coordination geometry in which the Schiff base ligand acts as a cis-O,N,N',O'-tetradentate ligand. The crystal structure is built up of centrosymmetric dimer units stacked into chains along the [010] direction. Adjacent chains associate via C-H.

One-pot mechanosynthesis with three levels of molecular self-assembly: coordination bonds, hydrogen bonds and host-guest inclusion.

Liquid-assisted grinding (LAG) was used to combine three levels of molecular self-assembly into a one-pot mechanochemical approach for the construction of metal-organic materials. The approach was applied for the construction of three adducts of cobalt(II) dibenzoylmethanate with isonicotinamide, nicotinamide and imidazole, to screen for their inclusion compounds. The one-pot process consists of: i) The coordination-driven binding of addends to the equatorially-protected metal ion, resulting in "wheel-and-axle"-shaped complexes; ii) self-assembly of resulting complexes by way of hydrogen-bonded synthons to form metal-organic inclusion hosts; iii) in situ inclusion of the grinding liquid in the resulting host.

3-Acetylanilinium bromide, nitrate and dihydrogen phosphate: hydrogen-bonding motifs in one, two and three dimensions.

In the title compounds, namely 3-acetylanilinium bromide, C(8)H(10)NO(+) x Br(-), (I), 3-acetylanilinium nitrate, C(8)H(10)NO(+) x NO(3)(-), (II), and 3-acetylanilinium dihydrogen phosphate, C(8)H(10)NO(+) x H(2)PO(4)(-), (III), each asymmetric unit contains a discrete cation, with a protonated amino group, and an anion. In the crystal structure of (I), the ions are connected via N-H..

Partial ordering of tripivaloylmethane at 110 K.

Tripivaloylmethane [systematic name: 4-(2,2-dimethylpropanoyl)-2,2,6,6-tetramethylheptane-3,5-dione], C(16)H(28)O(3), is known to crystallize at room temperature in the space group R3m with three molecules in the unit cell. The molecules are conformationally chiral and pack so that each molecular site is occupied with equal probability by the two enantiomers. Upon cooling to 110 K, the structure partially orders; two molecules in the unit cell order into two different conformations of opposite chirality, while the third remains disordered.

Hydrogen bonding in the bromide salts of 4-aminobenzoic acid and 4-aminoacetophenone.

In the title compounds, 4-carboxyanilinium bromide, C(7)H(8)NO(2)(+) x Br(-), (I), and 4-acetylanilinium bromide, C(8)H(10)NO(+) x Br(-), (II), each asymmetric unit contains a discrete cation with a protonated amino group and a halide anion. Both crystal structures are characterized by two-dimensional hydrogen-bonded networks. The ions in (I) are connected via N-H.

Hydrogen-bonding motifs in 3-carboxyanilinium bromide and iodide.

In the title compounds, C(7)H(8)NO(2)(+).Br(-), (I), and C(7)H(8)NO(2)(+).I(-), (II), the asymmetric unit contains a discrete 3-carboxyanilinium cation, with a protonated amine group, and a halide anion.

Supramolecular motifs and solvatomorphism within the compounds [M(bpy)3]2[NbO(C2O4)(3)]Cl.nH2O (M = Fe2+, Co2+, Ni2+, Cu2+ and Zn2+; n = 11, 12). Syntheses, structures and magnetic properties.

Solvatomorphism has been found between two series of complexes of the composition [M(bpy)3]2[NbO(C2O4)3]Cl.nH2O [M = Fe2+ (1, 2), Co2+ (3, 4), Ni2+ (5, 6), Cu2+ (7) and Zn2+ (8, 9); bpy = 2,2'-bipyridine)], crystallizing in the monoclinic space group P2 1/c [3, 5, 8 (n = 11)] or in the orthorhombic space group P21 21 21 [2, 4, 6, 7 (n = 12)]. All the structures contain two symmetry independent [M(bpy)3]2+ cations, one [NbO(C2O4)3]3- anion, one Cl(-) anion, and crystal water molecules.

Conformational enantiomeric disorder in tripivaloylmethane.

Tripivaloylmethane [systematic name: 4-(2,2-dimethylpropanoyl)-2,2,6,6-tetramethylheptane-3,5-dione], C(16)H(28)O(3), is a 1,3,3'-triketone with C(3) molecular symmetry, prepared by alpha-acylation of 2,2,6,6-tetramethylheptane-3,5-dione with 2,2-dimethylpropanoyl anhydride in the presence of barium metal. The molecules are conformationally chiral and pack so that each molecular site is occupied with equal probability by the two enantiomers. The carbonyl groups of the two superimposed enantiomeric molecules are at an angle of 75.

(1,10-Phenanthroline-κN,N')bis-(2,2,6,6-tetra-methyl-heptane-3,5-dionato-κO,O')nickel(II).

The title compound, [Ni(C(11)H(19)O(2))(2)(C(12)H(8)N(2))], was obtained from the reaction of bis-(2,2,6,6-tetra-methyl-heptane-3,5-dionato)nickel(II), [Ni(dpm)], and 1,10-phenanthroline (phen). The Ni(II) ion is coordinated by four O atoms from two dpm ligands and two N atoms from a phen ligand in a slightly distorted octa-hedral environment. The methyl C atoms of two of the tert-butyl groups are disordered over two sites, having approximate occupancies of 0.

Enantiomeric bis(micro-N,N'-hexamethylenedisalicylaldiminato)dicopper(II) complexes.

The title dimeric complex, bis[micro-2,2'-[hexane-1,6-diylbis(nitrilomethylidyne)]diphenolato-1:2kappa(4)O,N:N',O']dicopper(II),[Cu(2)(C(20)H(22)N(2)O(2))(2)], has been investigated by single-crystal X-ray diffraction, by thermogravimetric analysis and differential scanning calorimetry, and also by FT-IR spectroscopy. Different synthetic and crystallization procedures gave crystals which were quite different in appearance, and it was initially thought that these were different polymorphic forms. Subsequent structure determination showed, in fact, serendipitous preparation of crystals in the P4(1) space group by one method and in space group P4(3) by the other.