Isoquinoline-based polycyclic lactams such as isoindoloisoquinolinones, pyrroloisoquinolinones, and benzo[a]quinolizinones were successfully assembled from the corresponding imides by using a TfOH-mediated (TfOH = trifluoromethanesulfonic acid) imide carbonyl activation and cyclization strategy. By employing this simple method, the isoquinoline
Understanding the mechanism of NO 2 interaction on semiconductor surfaces such as TiO 2 is a key step in designing the catalytic processes for conversion of NO 2 to useful products. In the present work, through density functional theory calculations and NEB simulations, we have performed a comprehensive electronic structure study and established the reaction steps for efficient conversion of NO 2 to HONO on TiO 2 surface in the presence of water vapor. We predict the dimerization of NO 2 to form a metastable N 2 O 4 . The latter's dissociation to NO δ+ and NO 3 δ− complexes occurs in two pathways: (i) direct disproportionation reaction and (ii) through formation of NO 2 δ+ and NO 2 δ− intermediates followed by O transfer. The introduction of H 2 O on a NO 2 chemisorbed surface leads to the formation of nitrous acid through the interaction of NO δ+ with the water. The reaction pathways leading to formation of nitrous and nitric acids are formulated.
Free standing silicene nanosheets remain elusive presumably due to the instability associated with sp(2) hybridized silicon atoms. Here we show that silicon prefers nanosheets based on the non-classical Si5 unit with a [1.1.1]-propellane motif that has two inverted tetrahedral atoms bridged by three tetrahedral atoms. DFT calculations show that nanosheets constructed exclusively from propellane building blocks are consistently more stable than those with sp(2) silicon atoms or their hybrids. These nanosheets also exhibit a narrow but definite band gap, unlike those reported earlier.
Quantum chemical analysis shows aza-graphane isomers, with alternate C-H and N: sites as ideal organocatalysts; their kinetic stability arises from the tertiary orthoamide. DFT calculations give split-off bands originating from nitrogen lone-pairs with substantial mixing of hydrogen, indicating an optimal balance between nitrogen basicity and C-H activation through the anomeric effect.
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