A structural variability of copper(I) chloride-tetrahydrothiophene adducts crystallizing in polymeric forms and exhibiting polymorphism: The role of the solvent

The function of the solvent in the self-assembling mode of [CuCl] with tetrahydrothiophene is reported. Copper(l) chloride has been used in the form of [CuCOCl] _n , which is slightly soluble in the most common solvents, and to allow an homogeneous phase reaction. The reaction of [CuCOCl] _n with THT gave [(CuCl)₂(THT)₃] _x ,1, in CH₃OH, [(CuCl)(THT)₂] _x ,2 in THF [(CuCl)(THT)] _x ,3, in CH₂Cl₂, and [(CuCl)₃(THT)₂] _x ,4, in DME. Compound1 consists of polymeric chains of centrosymmetric Cu₂Cl₂ dinuclear units bridged by THIT molecules running parallel to the [101] axis. In the structure of2 we found polymeric layers generated from the [(CuCl)(THT)] asymmetric unit by the center of symmetry and by the twofold axis. In compound3 the structure consists of layers generated through the center of symmetry by the [(Cu₂Cl₂)(THT)₂] asymmetric unit, while4 consists of layers generated through the center of symmetry by the [(Cu₃Cl₃)(THT)₂] asymmetric unit. Crystallographic details are as [ollows:2 is monoclinic, space group P2₁/c.a=9.657(3) A,b=6.441(2) A,c=11.459(3) A,\=111.96(2)°,V=661.0(4) A³. andR=0.075;3 is monoclinic, space group P2₁/n,a=19.327(7) A,b=6.703(2) A,c=10.116(3) A,ß=103.04(3)°,V=1276.7(7) A³ andR=0.043:4 is triclinic, space group Pl,a=12.513(2) A,b=6.698(1) A,c=9.651(1) A,=91.98(1)°,\=107.86(1)°,=74.59(1)°,V=741.2(2) A³, andR=0.044.     

High nuclearity manganese(III) compounds containing phenol-pyrazole ligands: the influence of the ligand on the core geometry

Three high-nuclearity manganese(III) clusters have been synthesized and characterized: [Mn?(μ?-O)?(phpzH)?(thf)?] (1), [Mn?(μ?-O)?(phpzH)?(EtOH)?]·2EtOH (2), and [Mn?(μ?-O)?(μ?-Br)?(HphpzEt)?(phpzEt)] (3). Compounds 1 and 2 contain a [Mn?(μ?-O?)(phpzH)?] core in which antiferromagnetic interactions between the manganese(III) ions are found. Compound 3 is a hexanuclear manganese(III) cluster in which weak ferromagnetic interactions appear to be operative. The formation and the stability of the cluster cores in relation to the type of phenol-pyrazole ligand and the reaction conditions are discussed.     

Novel 3‐benzoyl‐2‐piperazinylquinoxaline derivatives as potential antitumor agents

A series of new benzoylquinoxaline derivatives ( 7‐26 ) was synthesized and evaluated for antitumor activity against a panel of 60 human cell lines at the NCI of Bethesda. Among the compounds which have passed the preliminary screening, compound 23 exhibited the best profile and growth inhibition activity at 100 ‐ 10 μM. The compounds were then tested towards a folate‐dependent enzymes bio‐library including Thymidylate synthases enzymes and human Dihydrofolate reductase at 10 μM. The most of compounds exhibited a moderate inhibitory activity towards all or some of the enzymes tested with detectable inhibition constants (K_i) values in the range of 0.6‐70 μM. Compounds 21, 23, 24 showed K_i in the range of 10‐38 μM against both hDHFR and hTS.     

Amination of CF3-enones with nosyloxycarbamates

CF3-enones showed a different reactivity in amination reactions with nosyloxycarbamates. 4-Oxazolines or vinyl carbamates were obtained as unique products depending on the nature of double-bond substituents and on the choice of carbamates and bases. Starting from trans-trifluoroacetyl olefins carrying a heterocyclic residue or the p-methoxyphenyl group on the double bond, a rare loss of CF3CO was observed when the aminations were performed under heterogeneous conditions using CaO as the base.     

Stability of the equilibrium state of the equation system of a viscous barotropic gas in the model of atmosphere

Abstract We consider the system of equations of viscous gas motion whose pressure is related to the density by the law with 1<γ <2, in a domain defined by two levels of geopotential. Under the force due to geopotential and the Coriolis force, we prove the stability of the equilibrium state in a suitable Sobolev space. Keywords: Viscous barotropic gas, Equilibrium state, Coriolis force Mathematics Subject Classification (2000): 35Q35, 76N15     

Parallel solution-phase synthesis of acrylonitrile scaffolds carrying L-alpha-amino acidic or D-glycosyl residues

A practical and straightforward protocol for the preparation of a solution-phase library of acrylonitrile scaffolds is reported. Target compounds were obtained in high yield, stereoselectivity, and purity by two simple and practical steps from cyanoacetic acid. Moreover, our study proposes a synthetic approach starting from the constructed library to obtain three-membered heterocycles.     

Cationic calix[4]arenes as anion-selective ionophores

1,3-Alternate cationic calix[4]arene proved highly selective for proton/halogens symport transport and showed antiproliferative activity against murine monocyte/macrophage J774.A1 cancer cells.     

A New Strong-Acid Free Route to Produce Xanthan Gum-PANI Composite Scaffold Supporting Bioelectricity

Conductive hybrid xanthan gum (XG)–polyaniline (PANI) biocomposites forming 3D structures able to mimic electrical biological functions are synthesized by a strong-acid free medium. In situ aniline oxidative chemical polymerizations are performed in XG water dispersions to produce stable XG–PANI pseudoplastic fluids. XG–PANI composites with 3D architectures are obtained by subsequent freeze-drying processes. The morphological investigation highlights the formation of porous structures; UV–vis and Raman spectroscopy characterizations assess the chemical structure of the produced composites. I–V measurements evidence electrical conductivity of the samples, while electrochemical analyses point out their capability to respond to electric stimuli with electron and ion exchanges in physiological-like environment. Trial tests on prostate cancer cells evaluate biocompatibility of the XG–PANI composite. Obtained results demonstrate that a strong acid-free route produces an electrically conductive and electrochemically active XG–PANI polymer composite. The investigation of charge transport and transfer, as well as of biocompatibility properties of composite materials produced in aqueous environments, brings new perspective for exploitation of such materials in biomedical applications. In particular, the developed strategy can be used to realize biomaterials working as scaffolds that require electrical stimulations for inducing cell growth and communication or for biosignals monitoring and analysis.     

Synthesis of Chiral MOF-74 Frameworks by Post-Synthetic Modification by Using an Amino Acid

The synthesis of chiral metal–organic frameworks (MOFs) is highly relevant for asymmetric heterogenous catalysis, yet very challenging. Chiral MOFs with MOF-74 topology were synthesised by using post-synthetic modification with proline. Vibrational circular dichroism studies demonstrate that proline is the source of chirality. The solvents used in the synthesis play a key role in tuning the loading of proline and its interaction with the MOF-74 framework. In N,N′-dimethylformamide, proline coordinates monodentate to the Zn²⁺ ions within the MOF-74 framework, whereas it is only weakly bound to the framework when using methanol as solvent. Introducing chirality within the MOF-74 framework also leads to the formation of defects, with both the organic linker and metal ions missing from the framework. The formation of defects combined with the coordination of DMF and proline within the framework leads to a pore blocking effect. This is confirmed by adsorption studies and testing of the chiral MOFs in the asymmetric aldol reaction between acetone and para-nitrobenzaldehyde.     

Mass spectrometric studies of 2-aryl-5-acetylthiazole derivatives

Electron ionisation mass spectrometry was usefully used to characterize structurally 2-aryl-5-acetylthiazole derivatives in the gas phase. The compounds show characteristic fragmentation pathways depending on the chemical nature of the substituent at position 2, consisting mainly in the cleavage of both the 1,2- and 3,4-bonds of the thiazole ring. Liquid secondary ion mass spectrometry was applied to study the effects of protonation on the gas-phase unimolecular reactions of this class of compound. Tandem mass spectrometric experiments, carried out on molecular and protonated molecular ions, and also on fragment ions produced in the source, allowed the elucidation of gas-phase decompositions of low-internal energy ions.