Fe(NO3)3·9H2O as Efficient Catalyst for One‐pot Synthesis of Highly Functionalized Piperidines

Fe(NO₃)₃·9H₂O is used as an efficient and effective catalyst for the one‐pot three‐component synthesis of highly functionalized piperidines from aromatic aldehydes, anilines and b–ketoesters in ethanol at ambient temperature. This procedure includes some important aspects like the easy work‐up, no need to column chromatography, simple and readily available precursors, and good to high yields.     

On isometries in GMV-algebras

Let A = (A,⊕,⁻,^∼, 0, 1) be a GMV-algebra and ρ: A × A → A the distance function on A defined by ρ(x, y) = (x∨y)−(x∧y) for each x, y ∈ A.     

Application and developing of iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs) as an efficient and reusable heterogeneous nanocatalyst in the synthesis of heterocyclic compounds

Iron‐doped multi‐walled carbon nanotubes (Fe/MWCNTs) is an efficient, ecofriendly and reusable heterogeneous nanocatalyst for the one‐pot synthesis of heterocyclic compounds including bis‐spiro piperidines, piperidines, dihydro‐2‐oxopyrroles, pyrazoles and diazepines at room temperature with good to excellent yields. The heterogeneous nanocatalyst was fully characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), inductively coupled plasma (ICP) and FT‐IR analysis. Also, the structures of all prepared compounds were characterized by ¹H NMR, ¹³C NMR, FT‐IR, mass spectrometry (MS) and elemental analysis. The major advantages of these protocols are mild and green reaction conditions, short reaction times, clean reaction, operational simplicity, easy purification and good to excellent yields with the reusable heterogeneous nanocatalyst. The catalyst was ten recycled without significant loss of activity.     

Tin-Naphthalene Sulfonic Acid Complexes as Photostabilizers for Poly(vinyl chloride)

Poly(vinyl chloride) degrades when exposed to ultraviolet light for long durations; therefore, the photostability of polymeric materials should be enhanced through the application of additives. New organotin complexes containing 4-aminonaphthalene-1-sulfonic acid were synthesized and their role as poly(vinyl chloride) photostabilizers were evaluated. The reaction of 4-amino-3-hydroxynaphthalene-1-sulfonic acid and appropriate di- or trisubstituted tin chloride (triphenyltin chloride, tributyltin chloride, dibutyltin dichloride, and dimethyltin dichloride) in methanol under reflux gave the corresponding tin-naphthalene complexes with yields of 75%–95%. Elemental analyses and spectroscopic techniques including infrared and nuclear magnetic resonance (proton and tin) were used to confirm their structures. The tin complexes were added to poly(vinyl chloride) to produce thin films that irradiated with ultraviolet light. Various parameters were assessed, such as the weight loss, formation of specific functional groups, changes in the surface due to photoirradiation, and rate constant of photodegradation, to test the role played by the organotin complexes to reduce photodegradation in polymeric films. The results proved that organotin complexes acted as photostabilizers in these circumstances. The weight loss, formation of fragments containing specific functional groups, and undesirable changes in the surface of polymeric films were limited in the presence of organotin complexes. Organotin complexes containing three phenyl groups showed the most desirable stabilization effect. These act as efficient primary and secondary photostabilizers, and as decomposers for peroxides. In addition, such an additive inhibits the dehydrochlorination process, which is the main cause of poly(vinyl chloride) photodegradation.     

Isometries and direct decompositions of pseudo MV-algebras

In the paper isometries in pseudo MV-algebras are investigated. It is shown that for every isometry f in a pseudo MV-algebra = (A, ⊕, ⁻, ^∼, 0, 1) there exists an internal direct decomposition of with commutative such that and for each x ∈ A. On the other hand, if is an internal direct decomposition of a pseudo MV-algebra = (A, ⊕, ⁻, ^∼, 0, 1) with commutative, then the mapping g: A → A defined by is an isometry in and .      

Theoretical Semiempirical Study of the Biomolecules Interaction with Carbon Nanotubes

Modeling of the quantum interaction properties of glycine radicals on the sidewalls of the single-walled carbon nanotubes (CNTs) is investigated by MINDO/3 (Modified Intermediate Neglect of Differential Overlap version 3) calculations. It is found that the interaction potential of the N-centered glycine radical with the tubes results in stable complexes when it reacts with the nitrogen atom (N² centered) and metastable conformations with C² atoms. We have studied the effect of the diameter–length characteristics of the CNT on binding the amino acid. Our results suggest that the binding energy is lower as the CNT diameter increases, while as the CNT length increases, the binding energy initially increases and then slightly fluctuates.