Eduard V. Ganin

Two new “onium” fluorosilicates, the products of interaction of fluorosilicic acid with 12-membered macrocycles: structures and spectroscopic properties

Two novel compounds, (L(1)H)(2)[SiF(6)] x 2H(2)O (1) and (L(2)H)(2)[SiF(5)(H(2)O)](2) x 3H(2)O (2), resulting from the reactions of H(2)SiF(6) with 4-aminobenzo-12-crown-4 (L(1)) and monoaza-12-crown-4 (L(2)), respectively, were studied by X-ray diffraction and characterised by IR and (19)F NMR spectroscopic methods. Both complexes have ionic structures due to the proton transfer from the fluorosilicic acid to the primary amine group in L(1) and secondary amine group incorporated into the macrocycle L(2). The structure of 1 is composed of [SiF(6)](2-) centrosymmetric anions, N-protonated cations (L(1)H)(+), and two water molecules, all components being bound in the layer through a system of NH[...]F, NH[...]O and OH[...]F hydrogen bonds. The [SiF(6)](2-) anions and water molecules are assembled into inorganic negatively-charged layers via OH[dot dot dot]F hydrogen bonds. The structure of 2 is a rare example of stabilisation of the complex anion [SiF(5)(H(2)O)](-), the labile product of hydrolytic transformations of the [SiF(6)](2-) anion in an aqueous solution. The components of 2, i.e., [SiF(5)(H(2)O)](-), (L(2)H)(+), and water molecules, are linked by a system of NH[...]F, NH[...]O, OH[...]F, OH[dot dot dot]O hydrogen bonds. In a way similar to 1, the [SiF(5)(H(2)O)](-) anions and water molecules in 2 are combined into an inorganic negatively-charged layer through OH[...]F and OH[...]O interactions.

Hydrogen-bonded frameworks of bis(2-carboxypyridinium) hexafluorosilicate and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate.

In bis(2-carboxypyridinium) hexafluorosilicate, 2C(6)H(6)NO(2)+.SiF6(2-), (I), and bis(2-carboxyquinolinium) hexafluorosilicate dihydrate, 2C(10)H(8)NO(2)+.SiF6(2-).2H2O, (II), the Si atoms of the anions reside on crystallographic centres of inversion. Primary inter-ion interactions in (I) occur via strong N-H...F and O-H...F hydrogen bonds, generating corrugated layers incorporating [SiF6](2-) anions as four-connected net nodes and organic cations as simple links in between. In (II), a set of strong N-H...F, O-H...O and O-H...F hydrogen bonds, involving water molecules, gives a three-dimensional heterocoordinated rutile-like framework that integrates [SiF6](2-) anions as six-connected and water molecules as three-connected nodes. The carboxyl groups of the cation are hydrogen bonded to the water molecule [O...O = 2.5533 (13) A], while the N-H group supports direct bonding to the anion [N...F = 2.7061 (12) A].

Inclusion of triphenylmethane derivatives by crown and linear O-containing molecules : selective interactions and crystal structures

The sulfamide derivative of triphenylmethanol, 3-[hydroxy(diphenyl)methyl]benzenesulfonamide (H2NSO2Ph)Ph2COH was synthesized and, alongside with the parent triphenylmethanol and triphenylmethylamine, was investigated for selective interactions with crown ethers of different dimensionality (12-18-membered cycles). The molecule of 12-crown-4 (12C4) appeared to be the best candidate for Ph3COH, Ph3CNH2 and Ph3CNH3·NCS, while (H2NSO2Ph)Ph2COH forms the complex exclusively with 18-crown-6 (18C6). The triphenylammonia trifluoroacetate, Ph3CNH3·CF3COO, selectively forms the complex only with 2-methoxyethanol. The crystalline products of the compositions (Ph3COH)2·12C4, (Ph3CNH2)2·12C4, (Ph3CNH3·NCS)2·12C4, [(H2NSO2Ph)Ph2COH]2·18C6 and Ph3CNH3·CF3COO CH3OCH2CH2OH were obtained and studied by X-ray single crystal diffraction.

Crystal structure of inclusion compounds: The complexes of thecis-syn-cis and thecis-anti-cis isomers of dicyclohexano-18-crown-6 with 4-methylbenzenesulfamide

The crystal structure of two complexes of the isomerscis-syn-cis (isomer A) andcis-anti-cis (isomer B) of dicyclohexano-18-crown-6 with 4-methylbenzenesulfamide have been determined by X-ray single crystal diffraction methods. The two structures have been solved by direct methods and refined to agreement values of 0.067 and 0.038 for isomers A and B respectively. The first isomer forms an inclusion compound with a host/guest ratio of 1 : I; the second one of I:2. The amino groups of the guest molecules are connected by N-H...O hydrogen bonds with oxygen atoms of the polyether molecules. The methyl groups of 4-methylbenzenesulfamide do not form hydrogen bonds.[/p]The host-guest interactions in the molecular complexes, the reciprocal influence of the two molecules on their conformation and the intermolecular contacts between the molecules in the crystal are discussed.

Tetrabenzylcyclen as a receptor for fluoride

A tetraazacyclic ligand, tetrabenzylcyclen (L), was synthesized using an improved method with a higher yield by treatment of cyclen with benzylchloride in the presence of potassium carbonate. The reaction of L with an aqueous solution of fluorosilicic acid yielded a mixed-anionic salt with the composition [H3L][F][SiF6]·4H2O (1). The single crystal X-ray study revealed that the macrocyclic tri-cation essentially changes the conformation compared to the free ligand in order to tightly accommodate the fluoride inside and to keep the hexafluorosilicate anions and water molecules outside in the solid state complex.

Supramolecular associates of para-aminobenzoic acid with N-and N,O-heterocyclic molecules

A series of novel supramolecular multicomponent complexes of para-aminobenzoic acid (PABA) with N-containing cyclic molecules and aza-crown ethers, (H2PPz)·(PABA)2·2H2O (1), (H2teta)·(PABA)2·H2O (2), (H2cyclen)·(PABA)2·2H2O (3), (H2-diazonia-12C4)·(PABA)2·2H2O (4), (H-azonia-18C6)·(PABA)·3H2O (5) (PPz = piperazine, teta = meso-5,7,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, cyclen = 1,4,7,10-tetraazacyclododecane, diaza-12-crown-4 = 1,7-dioxa-4,10-diazacyclododecane and aza-18-crown-6 = 1,4,7,10,13-pentaoxa-16-azacyclooctadecane) has been synthesized. Crystallographic studies reveal that all complexes are organic salts formed due to the proton transfer from the carboxylic group of PABA to the amino group of the macrocycle, and thus are comprised of PABA anion, macrocyclic mono- or dication and a variable number of water molecules. In all complexes the cations and anions are associated via (H2N+)NH⋯O(COO−) charge-assisted hydrogen bonds. The number of PABA involved in the complex equals to the number of N-protonated binding sites in the cyclic molecule. Water molecules play a significant role in the formation of the supramolecular architecture.

Inclusion complex of rac-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane with hydrochloride and water

In the crystal structure of the title compound, C 16 H 38 N 4 2+ .2Cl - .3H 2 O, a rather complex hydrogen-bonding network is observed. The macrocycle is stabilized as a dication, 5,5,7,12,12,14-hexamethyl-1,8-diaza-4,11 -diazoniacyclotetradecane, forming N-H...Cl and N-H...O hydrogen bonds. The water molecules are distinguished by their inequality in structure formation. They are involved in different types of intermolecular hydrogen bonding in the crystal lattice.