Highlights  Niobium-containing SBA-15 silica used as catalysts for a model reaction to biodiesel production.  High niobium content and high calcination temperature maintained SBA-15 mesoporous silica profile.  Solid evaluated as catalyst with low Nb concentration (2 wt.%) showed better catalytic performance.  Nb promoter effect: catalyst stability at low loadings and also lowest heating treatment.

Electronic structures and direct observation of adlayers on Au(111) of triangular expanded hemiporphyrazines that can be classified into azaporphyrinoids and which can trap three transition metal ions are reported. The electronic structure was examined by electronic absorption and magnetic circular dichroism (MCD) spectroscopies and interpreted in conjunction with molecular orbital (MO) calculations. Both metal-free and metallated compounds were 30 π-electron systems with n = 7 in 4n + 2 aromaticity. In addition, calculations of the anisotropy of the induced current density (ACID) and nucleus-independent chemical shift (NICS) were performed. The inner core region of the metal-free compound was weakly anti-aromatic or nonaromatic, but after metal insertion, this region increased aromatic character. The direct observation of adlayers of one of their cobalt and nickel complexes on Au(111) by scanning tunneling microscopy (STM) revealed that these three ions are arranged specifically in the shape of a triangle.

To obtain the properties of nanopores solids, N2 is usually used as probe molecule, however recently, IUPAC recommends using Ar instead. This study used experimental X-ray diffraction (XRD) analysis, Monte Carlo (MC), and hybrid reverse MC (HRMC) simulations to obtain information on the intermolecular structures of adsorbed N2 and Ar. Our results indicate that the quadrupole interaction between N2 molecules is relatively weak, and the N2 gives fairly good assessments as with Ar for porous carbons with low functional groups.

Cyclo­[9]­pyrrole, a ring-expanded porphyrin without meso-bridges and having an odd number of pyrroles, was synthesized via the oxidative coupling of 2,2′:5′,2″-terpyrrole. X-ray crystallography showed a C 2-like symmetry with a large root-mean-square deviation. The optical properties and electronic structures were analyzed using magnetic circular dichroism spectroscopy and time-dependent density functional theory calculations.