Besides the Mbius topology hexaphyrins can adopt a variety of conformations with Hckel and twisted Hckel topologies which can be interconverted under certain conditions

To determine the optimum conditions for viable Möbius topologies, the conformational preferences of [26]- and [28]hexaphyrins and the dynamic interconversion between the Möbius and Hückel topologies were investigated by density functional calculations. In the absence of meso substituents, [26]hexaphyrin prefers a planar dumbbell conformation, strongly aromatic and relatively strain free. The Möbius topology is highly improbable: the most stable tautomer is 33 kcal mol(-1) higher in energy than the global minimum. On the other hand, the Möbius conformer of [28]hexaphyrin is only 6 kcal mol(-1) higher in energy than the most stable dumbbell conformation. This marked difference is due to aromatic stabilization in the Möbius 4n electron macrocycle as opposed to antiaromatic destabilization in the 4n+2 electron system, as revealed by several energetic, magnetic, structural, and reactivity indices of aromaticity. For [28]hexaphyrins, the computed activation barrier for interconversion between the Möbius aromatic and Hückel antiaromatic conformers ranges from 7 to 10 kcal mol(-1), in very good agreement with the available experimental data.

The conformation of the hexaphyrin macrocycle is strongly dependent on oxidation state and solvent, and this feature creates a promising platform for the development of molecular The trigonal bipyramidal MN3M species: a new kind of aromatic complex containing A new kind of aromatic trigonal bipyramidal MN3M (M=Be, B, Mg, Al, and Ca) species, with all real frequencies, is obtained at the MP2/6-311+G(3d) level. The nucleus-independent chemical shift values are -1026 ppm for the N3 (3-) ring, and -749, -799, -656, -744, and -623 ppm (at the geometrical center of the trigonal bipyramid) for BeN3Be, BN3B, MgN3Mg, AlN3Al, and CaN3Ca, respectively. Molecular orbital analysis indicates that the regular triangular N3 (3-) ring and each MN3M species have three aromatic six-electron systems (pi, sigma(p), and sigma(s)) and exhibit threefold aromaticity. The CaN3Ca species has a very low vertical ionization energy of 34 eV at the CCSD(T)/6-311+G(3d) level, which is even lower than the ionization energy (3 eV) of the Cs atom. Therefore, CaN3Ca can be considered as a new superalkali species. A further study on the CaN3CaCl molecule confirms the superalkali characteristics of CaN3Ca. Two interesting phenomena are explored in the MN3M species: the delocalized electron cloud of the N3 subunit is elongated by two M cations, and the electron clouds of two M cations are distended by the N3 (3-) ring.

Monitoring the degradation capability of novel haloalkaliphilic tributyltin chloride (TBTCl) resistant bacteria from butyltin-polluted site.Biotechnology Research, Institute, University of Sadat City, Sadat City, Egypt; Department of Biological Science, Faculty of Science and Humanity Studies at Al-Quwayiyah, Shaqra University, Al-Quwayiyah 11971, Saudi Arabia. Electronic Tributyltin (TBT) is recognized as a major environmental problem at a global scale. View more (TBT)-degrading bacteria may be a key factor in the remediation of TBT polluted sites. In this work, three haloalkaliphilic bacteria strains were isolated from a TBT-contaminated site in the Mediterranean Sea. After analysis of the 16S rRNA gene sequences the isolates were identified as Sphingobium sp. HS1, Stenotrophomonas chelatiphaga HS2 and Rhizobium borbori HS5.

The optimal growth conditions for biodegradation of TBT by the three strains were pH 9 and 7% (w/v) salt concentration. S. chelatiphaga HS2 was the most effective TBT degrader and has the ability to transform most TBT into dibutyltin and monobutyltin (DBT and MBT). A gene was amplified from strain HS2 and identified as TBTB-permease-like, that encodes an ArsB-permease. A reverse transcription polymerase chain reaction analysis in the HS2 strain confirmed that the TBTB-permease-like gene contributes to TBT resistance. The three novel haloalkaliphilic TBT degraders have never been reported previously.Nanoreactors are material structures that provide engineered internal cavities that create unique confined nanoscale environments for chemical reactions.

Crumpled graphene nanoparticles or "nanosacks" may serve as nanoreactors when filled with reactive or catalytic particles and engineered for a specific chemical function. This article explores the behavior of crumpled graphene nanoreactors containing nanoscale ZnO, Ag, Ni, Cu, Fe, or TiO2 particles, either alone or in combination, in a series of case studies designed to reveal their fundamental behaviors. Photo Acid Generator shows that ZnO nanoparticles undergo rapid dissolution inside the nanoreactor cavity accompanied by diffusive release of soluble products to surrounding aqueous media through the irregular folded shell. Photoacid Generator demonstrates the open nature of the sack structure, which facilitates rapid small-molecule exchange between inside and outside that is a requirement for nanoreactor function.