The level of detail
attained in the computational description of
reaction mechanisms can be vastly improved through tools for automated
chemical space exploration, particularly for systems of small to medium
size. Under this approach, the unimolecular decomposition landscape
for indole was explored through the automated reaction mechanism discovery
program AutoMeKin. Nevertheless, the sheer complexity of the obtained
mechanisms might be a hindrance regarding their chemical interpretation.
In this spirit, the new Python library amk-tools has
been designed to read and manipulate complex reaction networks, greatly
simplifying their overall analysis. The package provides interactive
dashboards featuring visualizations of the network, the three-dimensional
(3D) molecular structures and vibrational normal modes of all chemical
species, and the corresponding energy profiles for selected pathways.
The combination of the joined mechanism generation and postprocessing
workflow with the rich chemistry of indole decomposition enabled us
to find new details of the reaction (obtained at the CCSD(T)/aug-cc-pVTZ//M06-2X/MG3S
level of theory) that were not reported before: (i) 16 pathways leading
to the formation of HCN and NH3 (via amino radical); (ii)
a barrierless reaction between methylene radical and phenyl isocyanide,
which might be an operative mechanism under the conditions of the
interstellar medium; and (iii) reaction channels leading to both hydrogen
cyanide and hydrogen isocyanide, of potential astrochemical interest
as the computed HNC/HCN ratios greatly exceed the calculated equilibrium
value at very low temperatures. The reported reaction networks can
be very valuable to supplement databases of kinetic data, which is
of remarkable interest for pyrolysis and astrochemical studies.
The
computational study of catalytic processes allows discovering
really intricate and detailed reaction mechanisms that involve many
species and transformations. This increasing level of detail can even
result detrimental when drawing conclusions from the computed mechanism,
as many coexisting reaction pathways can be in close competence. Here,
we present a reaction network-based implementation of the energy span
model in the form of a computational code, gTOFfee, capable of dealing
with any user-specified reaction network. This approach, compared
to microkinetic simulations, enables a much easier, simpler, and straightforward
analysis of the performance of any catalytic reaction network. In
this communication, we will go through the foundations and applicability
of the underlying model and will tackle the application to two relevant
catalytic systems: homogeneous Co-mediated propene hydroformylation
and heterogeneous CO2 hydrogenation over Cu(111).
Valorization of carbon dioxide into organic molecules using catalytic approaches has witnessed an upsurge in recent years. Here, the influence of an Al(III) aminotriphenolate complex on the regio-and stereochemical features of the coupling between carbon dioxide and a cyclic epoxy alcohol has been studied. Three distinct bicyclic carbonate products were produced from a single starting material, depending on the catalytic conditions. The proposed carbonate configurations were examined by solution and solid-phase techniques, including NMR spectroscopic and X-ray crystallographic analyses. Control experiments combined with DFT calculations provide a rationale for the distinct catalytic manifolds observed in the presence and absence of the Al(III) complex.
Heterometallic lanthanide [LnLn’] coordination complexes accessible thermodynamically are very scarce because the metals of this series have very similar chemical behaviour. Trinuclear systems of this category are virtually non-existent. A...
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