Organically interconnected graphene flakes: A flexible 3-D material with tunable electronic bandgap.

The structural and electronic properties of molecularly pillared graphene sheets were explored by performing Density Functional based Tight Binding calculations. Several different architectures were generated by varying the density of the pillars, the chemical composition of the organic molecule acting as a pillar and the pillar distribution. Our results show that by changing the pillars density and distribution we can tune the band gap transforming graphene from metallic to semiconducting in a continuous way. In addition, the chemical composition of the pillars affects the band gap in a lesser extent by introducing additional states in the valence or the conduction band and can act as a fine band gap tuning. These unique electronic properties controlled by design, makes Mollecular Pillared Graphene an excellent material for flexible electronics.

Exceptional gravimetric and volumetric CO2 uptake in a palladated NbO-type MOF utilizing cooperative acidic and basic, metal-CO2 interactions.

A novel NbO-type MOF is reported based on a palladated organic linker, showing a remarkable gravimetric and volumetric CO2 uptake, reaching 201.8 cm(3) g(-1) (9.0 mmol g(-1), 39.7 wt%) and 187.8 cm(3) cm(-3) at 273 K and 1 bar, respectively. Accurate theoretical calculations revealed that the exceptional CO2 uptake is due to the combination of Lewis base Pd(ii)-CO2 (24.3 kJ mol(-1)) and Lewis acid Cu(ii)-CO2 (30.3 kJ mol(-1)) interactions, as well as synergistic pore size effects.

Stereochemistry in the reaction of 4-methyl-1,2,4-triazoline-3,5-dione (MTAD) with beta,beta dimethyl-p-methoxystyrene. Are open biradicals the reaction intermediates?

The reaction of 4-methyl-1,2,4-triazoline-3,5-dione (MTAD) with beta,beta-dimethyl-p-methoxystyrene (1) in chloroform affords four adducts: the ene, two stereoisomeric [4 + 2]/ene diadducts, and a minor product that is probably the double Diels-Alder diadduct. In methanol, only one regioisomeric methoxy adduct is formed. The stereochemistry of the reaction was examined by specific labeling of the anti methyl group of 1 as CD(3). In chloroform, the ene adduct is formed with >97% synselectivity, while the [4 + 2]/ene diadducts are formed with 20% loss of stereochemistry at the methyl groups. In methanol, the methoxy adducts are formed with almost complete loss of stereochemistry. A mechanism involving open biradicals is inconsistent with the experimental results. It is likely that the reaction proceeds through the formation of an aziridinium imide and an open zwitterionic intermediate. The aziridinium imide leads to the formation of the ene adduct. The open zwitterion, which has sufficient lifetime to rotate around the C-C bond, leads to the formation of a [4 + 2] cycloadduct, which reacts with a second molecule of MTAD in an ene-type mode to afford two stereoisomeric [4 + 2]/ene diadducts. In methanol, solvent captures the zwitterionic intermediate and forms the methoxy adduct. The relative distribution of the products in chloroform depends on the reaction temperature. Lower temperatures favor the ene reaction (entropically favorable), whereas at higher temperatures the [4 + 2]/ene diadducts become the major products.

Cis- and trans-N-benzyl-octahydrobenzo[g]quinolines. Adrenergic and dopaminergic activity studies.

In vitro assays on a series of cis- and trans-octahydrobenzo[g]quinolines indicated an unusual trend of affinities at the dopaminergic receptors and alpha adrenoceptors. The trans N-benzyl analogues exhibited affinity at the alpha2 as well as the D1-like receptors whereas their N-unsubstituted congeners showed a distinct preference for the alpha2 adrenoceptor. Enhanced activity for the alpha2 receptors was also exhibited by the cis N-benzylated isomers. These observations are interpreted by theoretical calculations.

Catalytic action of Ni atoms in the formation of carbon nanotubes: a molecular dynamics study.

Catalytic action of Ni atoms in the growth of single-wall carbon nanotubes is investigated using tight-binding molecular dynamics and ab initio methods. Our results demonstrate this to be a two step process in which the Ni atom first creates and stabilizes defects in nanotubes. The subsequent incorporation of incoming carbon atoms anneals the Ni-stabilized defects freeing the Ni atom to repeat the catalytic process.

Site specificity in the photooxidation of some trisubstituted alkenes in thionin-supported zeolite Na-Y. On the role of the alkali metal cation

The less substituted side of some geminal dimethyl trisubstituted alkenes becomes significantly more reactive if photooxygenation takes place in thionin-supported zeolite Na-Y. These results are mainly attributed to a synergistic interaction between the alkali metal cation, the alkene, and the oxygen in the transition state of perepoxide formation.