Vanadium(V) Salen Complex Catalyzed Highly Enantioselective Cyanoformylation of Aldehydes in the Presence of Imidazole as a Cocatalyst

Toward the improvement of vibronic spectra and non-radiative rate constants using the vertical Hessian method

For the computation of vibrationally resolved electronic spectra, various approaches can be employed. Adiabatic approaches simulate vibronic transitions using harmonic potentials of the initial and final states, while vertical approaches extrapolate the final state potential from the gradients and Hessian at the Franck-Condon point, avoiding a full exploration of the potential energy surface of the final state. Our implementation of the vertical Hessian (VH) method has been validated with a benchmark set of four small molecules, each presenting unique challenges, such as complex topologies, problematic low-frequency vibrations, or significant geometrical changes upon electronic excitation. We assess the quality of both adiabatic and vertical approaches for simulating vibronic transitions. For two types of donor-acceptor compounds with promising thermally activated delayed fluorescence properties, our computations confirm that the vertical approaches outperform the adiabatic ones. The VH method significantly reduces computational costs and yields meaningful emission spectra, where adiabatic models fail. More importantly, we pioneer the use of the VH method for the computation of rate constants for non-radiative processes, such as intersystem crossing and reverse intersystem crossing along a relaxed interpolated pathway of a donor-acceptor compound. This study highlights the potential of the VH method to advance computational vibronic spectroscopy by providing meaningful simulations of intricate decay pathway mechanisms in complex molecular systems.

Nickel-Catalyzed Chemo- and Regioselective Arylcyanation of β,γ-Unsaturated Amides

A nickel-catalyzed intermolecular arylcyanation of 8-aminoquinolinyl β,γ-unsaturated amides is reported. The three-component reaction directly afforded diverse β-cyano γ-aryl amides with exclusive chemo- and regioselectivity. The synthetic practicality of this approach is further demonstrated through multigram scale reaction, expanded transformations of the nitrile product, late-stage modification of complex molecules, and direct drug synthesis.

Making Chiral Salen Complexes Work with Organocatalysts

Bisimine derivatives of salicylaldehyde with chiral diamines (salens) are privileged ligands in asymmetric organometallic catalysis, which can be used in cooperation with organocatalysts as additives. The latter can be a modifier of the metal reactivity by liganding or a true co-catalyst working in tandem or in a dual system. All scenarios encountered in the literature are reviewed and classified according to the organocatalyst. In each case, mechanistic and physical-organic chemistry considerations are discussed to better understand the gears of these complex catalytic settings.

Asymmetric Catalysis Using Chiral Salen-Metal Complexes: Recent Advances

Chiral salen-metal complexes are among the most versatile asymmetric catalysts and have found utility in fields ranging from materials chemistry to organic synthesis. These complexes are capable of inducing chirality in products formed from a wide variety of chemical processes, often with close to perfect stereoinduction. Salen ligands are tunable for steric as well as electronic properties, and their ability to coordinate a large number of metals gives the derived chiral salen-metal complex very broad utility in asymmetric catalysis. This review primarily summarizes developments in chiral salen-metal catalysis over the last two decades with particular emphasis on those applications of importance in asymmetric synthesis.

Immobilization of an acid–base cooperative catalyst on MCM-41 as a heterogeneous approach for the asymmetric cyanoethoxycarbonylation of isatins

Heterogenization of chiral quinine-thiourea catalyst for enantioselective cyanation reaction. The catalyst is found to be efficient and recyclable up to five times with retention of its catalytic activity.

Synthesis, characterization, DNA binding and cleavage studies of chiral Ru(II) salen complexes

Interaction of chiral Ru(II) salen complexes (S)-1 and (R)-1 with Calf Thymus DNA (CT-DNA) was studied by absorption spectroscopy, competitive binding study, viscosity measurements, CD measurements, thermal denaturation study and cleavage studies by agarose gel electrophoresis. The DNA binding affinity of (S)-1 (6.25 x 10(3)M(-1)) was found to be greater than (R)-1 (3.0 x 10(3)M(-1)). The antimicrobial studies of these complexes on five different gram (+)/(-) bacteria and three different fungal organisms showed selective inhibition of the growth of gram (+) bacteria and were not affective against gram (-) and fungal organisms. Further, the (S)-1 enantiomer inhibited the growth of organisms to a greater extent as compared to (R)-1 enantiomer.