Dissolution of gold in the DMSO—RX systems. The concept of a donor-acceptor electron transport system

Summary The liquid phase oxidation of gold in donor-acceptor organic and aqueous-organic media has been studied. The compounds [AuCl(Me₂S)], [AuBr(Me₂S)], [AuBr₃(Me₂S)], [Me₃S][AuBr₄], [Me₃S][AuBr₄(Me₂S)]·H₂O, [Me₃SO]-[AuBr₄]·H₂O, [Me₃S][Au₂Br₇(Me₂S)₂]·3H₂O, [Me₃S]₂-[Au₂Br₈]·2DMSO·H₂O, [Me₂(Bu)SO][AuBr₄]·H₂O and [Me₃S]Br were isolated by dissolution of Au⁰ in DMSO-RX mixtures (R = H or Bu; X = Cl or Br). The products were characterized by elemental analysis and i.r. spectroscopy. The nature of the Au⁰-DMSO-RX systems and the oxidant species are discussed in terms of a newly-developed concept of donor-acceptor electron transport (DAET) systems.     

Formation of a tris-capsule and a tris-carceplex from a cyclic six-bowl assembly

A macrocycle composed of six cavitands was assembled into a tris-capsule and a tris-carceplex, each of which encapsulates three guest molecules.     

NMR determination of enantiomeric composition of 1-substituted 3-amino-1,2-dicarba-closo-dodecaboranes using Eu(hfc)3

Experimental conditions for determination of enantiomeric composition of 1-substituted 3-aminocarboranes by ¹H and ¹³C NMR spectroscopy using chiral shift reagent Eu(hfc)₃ have been found.     

A new approach to fluorinated 4(3H)-quinazolinones

A new approach for the synthesis of fluorinated 1H-quinazolin-4-ones and 4-substituted quinazolines has been developed. 6-Fluoro-1H-quinazolin-4-ones were obtained by intramolecular cyclization of fluorine-containing S-ethyl N-benzoylisothioureas. Nucleophilic substitution reactions at positions 2 and 7, as well as alkylation at 1-position of quinazolinones were investigated. In addition, the synthesis of fluorine-containing 4-aminoquinazolines was carried out.     

Phosphorus-based SAHA analogues as histone deacetylase inhibitors

[structure: see text] Three analogues of suberoyl anilide hydroxamic acid (SAHA) with phosphorus metal-chelating functionalities were synthesized as inhibitors of histone deacetylases (HDACs). The compounds showed weak activity for HeLa nuclear extracts (IC(50) = 0.57-6.1 mM), HDAC8 (IC(50) = 0.28-0.41 mM), and histone-deacetylase-like protein (HDLP, IC(50) = 0.33-1.9 mM), suggesting that the transition state of HDAC is not analogous to zinc proteases. Antiproliferative activity against A2780 cancer cells (IC(50) = 0.11-0.12 mM), comparable to SAHA (0.15 mM), was observed.     

Complexing processes in M(II)-dithiomalonamide-diacetyl triple systems (M= Ni,Cu) in ethanol solution and in a metal(II)hexacyanoferrate(II) gelatin-immobilized matrix materials

The complexing processes in the M ^II -dithiomalonamide-diacetyl triple system (M=Ni, Cu) occuring in the nickel(II)- and copper(II)hexacyanoferrate(II) gelatin-immobilized matrix in contact with aqueous alkaline solutions (pH~12) containing dithiomalonamide and diacetyl at room temperature, and between MCl₂, dithiomalonamide and diacetyl in EtOH solutions upon heating to$80°C, have been studied. In the Ni ^II -dithiomalonamide-diacetyl system, template synthesis occurs in EtOH solution but does not occur in the gelatin-immobilized matrix, whereas in the Cu ^II -dithiomalonamide-diacetyl system, template synthesis occurs in the gelatin-immobilized matrix but not in EtOH solution. Dithiomalonamide and diacetyl are the ligand synthons in the processes indicated.     

Rigid versus flexible: how important is ligand "preorganization" for metal ion recognition by lower rim-functionalized calix[4]arenes?

For an assessment of the outcomes from use of an appropriately "preorganized" calixarene-based ionophore versus its conformationally mobile prototype, solvent extraction propensities of flexible calix[4]arene di-[N-(X-sulfonyl)carboxamides] for alkali, alkaline earth metal cations, Pb2+, Ag+ and Hg2+ are compared with those for seven new rigid analogs fixed in the cone, partial cone and 1,3-alternate conformations. For each of the metal ions, the preferred calix[4]arene conformation was determined from the NMR spectra for the metal salt of the flexible ligand. Except for Ag+, flexible calix[4]arene di-[N-(X-sulfonyl)carboxamides] were found to provide greater metal ion extraction efficiency and better selectivity than the corresponding "preorganized" ionophores.     

Formation of supported size-controlled nanoparticles of sulfated zirconia

Methods of the preparation of catalysts for alkane skeletal isomerization based on uniform nanoparticles of sulfated zirconia anchored to different supports were investigated. These catalysts were characterized by using the ICP, HRTEM and BET techniques. The activities of the catalysts in the reaction of n-butane isomerization were measured and compared with those of bulk catalysts.     

A window fourier domain search system

A search system is presented that utilizes Fourier domain data. This system removes dominating features from the infrared absorbance data, transforms the data into the Fourier domain and performs a complete library search. The actual matching algorithm is very simple and excellent search results were attained using 16 cm^–1 resolution infrared absorbance spectra before transformation. This method can be used to distinguish very similar spectra that cannot be distinguished by many other search methods.