GaCl3-Catalyzed C-H Cyanation of Indoles with N-Cyanosuccinimide.

An efficient GaCl3-catalyzed direct cyanation of indoles and pyrroles using bench-stable electrophilic cyanating agent N-cyanosuccinimide was achieved and afforded 3-cyanoindoles and 2-cyanopyrroles in good yields and excellent regioselectivities. Notably, this protocol exhibited high reactivity for unprotected indoles and was applicable to a broad range of indole and pyrrole substrates.

CO2 -Promoted Direct Acylation of Amines and Phenols by the Activation of Inert Thioacid Salts.

Herein a carbon dioxide-promoted synthetic approach for the direct amidation between unactivated thioacid salts and amines under mild conditions was developed for a wide range of substrates. The method afforded amides in good to excellent yields under transition-metal-free and activation-reagent-free conditions, in sharp contrast to early methodologies on amide synthesis based on transition-metal catalysis. The method offered a greener and transition metal-free protocol applicable to pharmaceuticals preparations. Phenolic compounds were also found to be suitable acylation substrates with potassium thiosulfide KHS as the only byproduct. Moreover, this approach was applied to amide synthesis of valuable bio-active molecules such as moclobemide, melatonin, and a fungicide. Insights into the reaction mechanism involving carbon dioxide were provided through NMR spectroscopy and computational calculations. A plausible mechanism was proposed that involves weak interactions between carbon dioxide and potassium thioacetate in a dynamic equilibrium state formation of a six-membered ring.

Synthesis of cyano-2,3-dihydropyrrolo[1,2-f]phenanthridine derivatives via a domino-Knoevenagel-cyclization.

In a new multicomponent reaction phenanthridine reacts with isocyanides and malonitrile in the presence of benzaldehyde derivatives to produce 2-aryl-3-(alkyl- or arylimino)-2,3-dihydropyrrolo[1,2-f]phenanthridine-1,1(12b H)-dicarbonitrile in a simple, mild, and efficient protocol in excellent yields.

(Acetyl-acetonato)(dicyanamido)(1,10-phenanthroline)copper(II) dihydrate.

In the title compound, [Cu(C(5)H(7)O(2))(C(2)N(3))(C(12)H(8)N(2))]·2H(2)O, the Cu(II) atom is five-coordinated in a square-pyramidal geometry with two acetyl-acetonate O and two phenanthroline N atoms forming the base. The apical position is occupied by the central N atom of the dicyanamide ligand. The dicyanamide N atoms are each involved in hydrogen bonds to water mol-ecules. There are also hydrogen bonds between both the water mol-ecules and their centrosymmetric pairs, creating a hydrogen-bonded chain along the b-axis direction.

Magnetite ferrofluids stabilized by sulfonato-calixarenes.

Magnetite (Fe304) nanoparticles stabilised by sulfonatocalixarene macrocycles are readily accessible by a rapid in situ co-precipitation, and exhibit ferro-fluidic and superparamagnetic behaviour.

Calix[5]arene: a versatile sublimate that displays gas sorption properties.

Varied temperature sublimation of calix[5]arene results in the formation of two distinctly different crystal structures or polymorphs alpha and beta, the latter of which is based on both 'self-included' and 'back-to-back' helical arrangements of the molecule, while also being active towards CO2 sorption at room temperature and 1 atmosphere pressure.

Non-covalent expansion of an organic bilayer involving exo-cavity interplay of tetraphenylphosphonium with para-sulfonato-calix[4]arene.

Reaction of equimolar amounts of sodium para-sulfonato-calix[4]arene, tetraphenylphosphonium chloride and ytterbium chloride in water results in the formation of a mineral clay-like structure, where the hydrophobic tetraphenylphosphonium cations interpose a bilayer arrangement based on a 2D coordination polymer of (calix[4]arene)5-/Na+/Yb3+.

Constructing 2D porous material based on the assembly of large organic ions: p-sulfonatocalix[8]arene and tetraphenylphosphonium ions.

In the presence of tetraphenylphosphonium and aquated ytterbium(III) ions, conformationally flexible p-sulfonato-calix[8]arene forms an extended structure with two dimensional porosity involving the assembly of phosphonium cations and 'molecular capsules' comprised of two calixarenes shrouding three phosphonium cations.

Lanthanide-induced helical arrays of [{Co(III) sepulchrate} intersection {p-sulfonatocalix[4]arene}] supermolecules.

In the presence of lanthanide ions, a Co(III) sepulchrate cation [Co(diHOsar)]3+ and sodium p-sulfonatocalix[4]arene form a 1:1 host-guest complex which is self-assembled into a zeolite-like lattice network comprised of parallel, single stranded helices.

'Molecular capsules' based on p-sulfonatocalix[6]arene shrouding two tetraphenylphosphonium cations.

p-Sulfonatocalix[6]arene in the double cone conformation forms a molecular capsule-like arrangement confining two tetraphenylphosphonium cations, as part of an extended structure involving layers of additional tetraphenylphosphonium cations, aquated lanthanide ions and a large array of water molecules.

Inter-digitation approach to encapsulation of C60: [C60 [symbol: see text] (p-phenylcalix[5]arene)2].

p-Phenylcalix[5]arene shows a strong and selective binding of C60 in toluene resulting in crystallisation of a hemispherically inter-digitated 2:1 complex; the receptor itself crystallizes from toluene with self assembly through phenyl group inclusion.

Exploiting phenyl embraces and pi-stacking in the assembly of arrays of tetraphenylphosphonium p-sulfonatocalix[4]arene.

Phenyl embraces involving tetraphenylphosphonium cations feature in complexes of p-sulfonatocalix[4]arene where a phenyl ring of a cation is included in the cavity of the calixarene. The overall structures are based on pseudo-polymorphic supramolecular arrays and their formation is templated or induced by lanthanide ions.

Efficient synthesis of stable phosphonate ylides and phosphonate esters: reaction between activated acetylenes and triphenylphosphite in the presence of sulfonamide and heterocyclic NH-acids.

An efficient synthesis of stable phosphonate ylides and phosphonate esters is described via a one-pot reaction between activated acetylenes and triphenylphosphite in the presence of sulfonamides and heterocyclic NH-acids. Single X-ray diffraction analysis and NMR studies were used in characterizing the ylides and phosphonate ester products. Dynamic NMR studies performed on a phosphonate ylide allowed the calculation of the free energy barrier for the inter-conversion between the geometrical isomers (E) and (Z).

Layered Calcium Structures of p-Phosphonic Acid O-Methyl-Calix[6]arene.

Hexamethoxy-calix[6]arene has been fully functionalized with p-phosphonic acid groups on the upper rim in 57% yield over three steps, and has been authenticated in the solid state by X-ray diffraction as either a nitrate salt or one of two calcium complexes. The latter differ by the ratio of calcium ions per calixarene, either 3:1 or 4:1. In both structures the coordination sphere of the calcium ions is made up of oxygen atoms from the phosphonic acid groups and from water of crystallization, as part of extended polymeric layers in the extended 3D packing. Hirshfeld surface analysis shows extensive O...H and O...Ca interactions for the phosphonic acid moieties in both calcium structures. MALDI-TOF MS of the hexaphosphonic acid shows nano-arrays consisting of up to a maximum of 28 calixarene units.

Organization of lower rim O-alkylated p-phosphonic acid calix[4]arenes.

Lower rim O-methyl, -n-butyl, and n-octadecyl calix[4]arenes bearing p-phosphonic acid groups on the upper rim have been prepared in high yield, compounds 12-14. Where possible the compounds have been characterized in the solid state using X-ray diffraction, or as the precursor phosphate esters or a cesium salt. The cone conformation ethyl phosphate ester for the octadecyl compound crystallizes in a bi-layer 39.1 A thick which approaches the 40 A of biological membranes. The 1,3-alternate cone conformation of the cesium salt of the O-methyl phosphonic acid has a metal ion coordinated to two methoxy groups, four O-P (two from neighboring calixarenes), and two eta(3)-C(3) moieties from two 1,3-disposed aromatic rings. MALDI-TOF spectra of compounds 12-14 show successive peaks corresponding to 15, 33 and 16 calixarene units, which is consistent with the intra-molecular H-bonding capabilities of the di-protic phosphonic acid groups where the calixarenes are arranged into layers, including bilayers.

Carborane inclusion chemistry for the uncommon calix[7,9]arenes.

The inclusion of o-carborane by p-Bu(t)-calix[7,9]arenes has been investigated by solid state and solution studies, with both resulting complexes in the solid state being rich in carborane with the ratio of calixarene to carborane at 1 : 7 and 2 : 7 respectively. The carboranes reside in clefts within the calixarenes which arise from specific local conformations of adjacent phenolic groups, or are included in the extended structure through other interplay of the calixarenes and carboranes in such clefts.

Engineering nanorafts of calixarene polyphosphonates.

The water-soluble calix[4]arene bearing p-substituted phosphonic acid groups is accessible in five steps in overall 62 % yield, with the hydrogen-bonding prowess of the acidic groups dominating its self-assembly processes. These include the formation of 3.0(3) nm and 20(2) nm nanorafts of the calixarene in water using spinning disc processing, stabilized by acetonitrile, and nanorafts in the gas phase (

Controlling the confinement and alignment of fullerene C(70) in para-substituted calix[5]arenes.

In toluene fullerene C(70) forms 2:1 complexes with p-benzylcalix[5]arene (1) and p-phenylcalix[5]arene (2), [C(70) subset1(2)].6(C(7)H(8)) and [C(70) subset2(2)].7(C(7)H(8)). The fullerene molecules are completely shrouded by two calix[5]arenes in addition to terminal benzyl groups from other supermolecules, [C(70) subset1(2)], and solvent. Within the capsule-like supermolecules the calixarenes have distinctly different arrangements relative to the principal axis of the fullerene; for [C(70) subset1(2)].6(C(7)H(8)) the oxygen planes of the two calixarenes are skewed by 37.0 and 47.5 degrees , whereas in [C(70) subset2(2)].7(C(7)H(8)) the principal axes of the fullerene and the two encapsulating calixarenes are more closely aligned with the corresponding angles at 9.7 and 8.6 degrees , and features a pentaphenyl inter-calixarene embrace. The Hirshfeld surfaces of these two complexes have been investigated for a detailed understanding of the orientation and nature of interactions of C(70) with the cavitand-type molecules and toluene.

Solution and solid state studies on the binding of isomeric carboranes C2B10H12 by p-Bu(t)-calix[5]arene.

p-Bu(t)-calix[5]arene forms crystalline inclusion complexes with o- and m-carboranes in toluene or dichloromethane-hexane, but not with the p-isomer, the extended structures being based on 1 : 1 host-guest supermolecules, with the p-Bu(t)-substituents creating a snug fit for o- and m-carborane; p-carborane forms a highly hexane soluble complex, induced by grinding, which crystallizes as fibres. Solution phase studies showed the presence of a 1 : 1 host-guest stoichiometry with all three isomeric carboranes as determined from Job plots. The association constants for the o- and m-carborane complexes are 6.4 +/- 0.3 M(-1) and 3.8 +/- 0.1 M(-1) respectively, whereas the p-isomer is only weakly associated. Competition experiments involving all three isomers show rapid exchange on the NMR time scale, and no selectivity in solution is evident. Selective association involving the o- and m-isomers in the solid state is therefore remarkable, and it is a manifestation of crystal packing forces which embodies the differences in dipole moments of the carboranes.

Fine tuning the production of nanosized beta-carotene particles using spinning disk processing.

Nanoparticles of trans-beta-carotene are accessible using spinning disk processing (SDP), by varying the reaction conditions and the choice of surfactant, macrocyclic amphiphiles, sulfonato-calix[4,5,6,8]arenes, and alpha,beta-cyclodextrins. SDP ensures rapid mixing and fast kinetics, and nanoparticles of the carotene formed in the presence of the calixarenes are stable with respect to extraction of the carotene into an organic solvent, unlike in the presence of the cyclodextrins. Insight into the supramolecular structure of the carotene nanoparticles has also been established. The mean particle sizes (dynamic light scattering, DLS) have been optimized at 40(2) and 56(1) nm and 71.4(6) and 82(1) nm, respectively, for each sulfonato-calix[5,6 and 4,8]arene, whereas the cyclodextrins form nanoparticles with a mean diameter of 71(1) and 68.5(6) nm, respectively. Zeta-potential studies show stability of all the colloidal dispersions at pH > 4 with values below -30 mV. UV-visible spectroscopy shows a blue shift indicative of H-aggregates of the carotene within the nanoparticles. The surface area derived from BET studies is 39.12 m(2)/g corresponding to particles of 76.7(5) nm in diameter, in agreement with sizes obtained from DLS and TEM measurements.