Facile kinetic induction of a dihydropyridide to pyrrolide ring contraction

A sterically demanding N-aryl carbodiimide reacts with magnesium 1,4-dihydropyridides to initiate heterocyclic ring contraction and pyrrolide formation under unprecedentedly mild conditions.</p

An In-Depth Study of the Use of Eosin Y for the Solar Photocatalytic Oxidative Coupling of Benzylic Amines

The direct utilization of solar light for synthetic photochemistry is a sustainable and efficient technological goal. Herein we report the first in-depth study on the use of the inexpensive organic photocatalyst eosin Y for solar photocatalysis by demonstrating the oxidative coupling of benzylic amines to form imines, a class of valuable intermediates in chemical synthesis. By the use of a unique experimental setup with a custom-built variable-intensity solar light simulator, replication of a natural-sunlight environment was achieved. The relative significance of different variables on the reaction rate constant was quantitatively evaluated through comprehensive experimental design. Reaction kinetics and mechanistic information were obtained using both a batch reactor and a spinning-disc reactor. A maximum pseudo-first-order rate constant of 1.59 × 10^–3 s^–1 was obtained at a maximum turnover frequency of 192 h^–1 through optimization of the reaction conditions. Experiments carried out using a spinning-disc reactor confirmed that the reaction was not mass-transfer-limited but rather photon-transfer-limited

Harnessing Plasticity in an Amine-Borane as a Piezoelectric and Pyroelectric Flexible Film

We demonstrate that trimethylamine borane can exhibit desirable piezoelectric and pyroelectric properties. The material was shown to be able operate as a flexible film for both thermal sensing, thermal energy conversion and mechanical sensing with high open circuit voltages (&gt;10 V). A piezoelectric coefficient of d33≈10–16 pC N−1, and pyroelectric coefficient of p≈25.8 μC m−2 K−1 were achieved after poling, with high pyroelectric figure of merits for sensing and harvesting, along with a relative permittivity of (Formula presented.) 6.3.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Aerospace Structures & Material

Helical frontier orbitals of conjugated linear molecules

Compounds containing allenes, cumulenes and oligoynes (polyalkynes) have attracted attention for both their conformation and reactivity. Whilst the textbook molecular orbital description explains the general electronic and molecular structure of the cumulenes, there are anomalies in both the crystal structures and cycloaddition products involving oligoynes and allenes; the understanding of these molecules is incomplete. Through a computational study we elucidate that the frontier orbitals of the allene and oligoyne families are extended helices. These orbitals are the linear analogue to the Mobius aromatic systems, which also display non-linear pi interactions. The axial chirality found in allenes and oligoynes is intimately related to the topology of the frontier orbitals, and has implications for predictions of cycloaddition pathways, structure stability and spectroscopy

Helical Frontier Orbitals of Conjugated Linear Molecules

Compounds containing allenes, cumulenes and oligoynes (polyalkynes) have attracted attention for both their conformation and reactivity. Whilst the textbook molecular orbital description explains the general electronic and molecular structure of the cumulenes, there are anomalies in both the crystal structures and cycloaddition products involving oligoynes and allenes; the understanding of these molecules is incomplete. Through a computational study we elucidate that the frontier orbitals of the allene and oligoyne families are extended helices. These orbitals are the linear analogue to the Möbius aromatic systems, which also display non-linear p interactions. The axial chirality found in allenes and oligoynes is intimately related to the topology of the frontier orbitals, and has implications for predictions of cycloaddition pathways, structure stability and spectroscopy

Helical frontier orbitals of conjugated linear molecules

Compounds containing allenes, cumulenes and oligoynes (polyalkynes) have attracted attention for both their conformation and reactivity. Whilst the textbook molecular orbital description explains the general electronic and molecular structure of the cumulenes, there are anomalies in both the crystal structures and cycloaddition products involving oligoynes and allenes; the understanding of these molecules is incomplete. Through a computational study we elucidate that the frontier orbitals of the allene and oligoyne families are extended helices. These orbitals are the linear analogue to the Mobius aromatic systems, which also display non-linear pi interactions. The axial chirality found in allenes and oligoynes is intimately related to the topology of the frontier orbitals, and has implications for predictions of cycloaddition pathways, structure stability and spectroscopy