How the Donor/Acceptor Spin States Affect the Electronic Couplings in Molecular Charge-Transfer Processes?

Adam’s milestone paper on electronic couplings dependency on spin states has just been published in the Journal of Chemical Theory and Computation: “How the Donor/Acceptor Spin States Affect the Electronic Couplings in Molecular Charge-Transfer Processes?”

Abstract:

The electronic coupling matrix element HAB is an essential ingredient of most electron-transfer theories. HAB depends on the overlap between donor and acceptor wave functions and is affected by the involved states’ spin. We classify the spin-state effects into three categories: orbital occupation, spin-dependent electron density, and density delocalization. The orbital occupancy reflects the diverse chemical nature and reactivity of the spin states of interest. The effect of spin-dependent density is related to a more compact electron density cloud at lower spin states due to decreased exchange interactions between electrons. Density delocalization is strongly connected with the covalency concept that increases the spatial extent of the diabatic state’s electron density in specific directions. We illustrate these effects with high-level ab initio calculations on model direct donor–acceptor systems relevant to metal oxide materials and biological electron transfer. Obtained results can be used to benchmark existing methods for HAB calculations in complicated cases such as spin-crossover materials or antiferromagnetically coupled systems.

Read it online free:

https://pubs.acs.org/doi/10.1021/acs.jctc.1c00126

New paper is out – validation of Lerf-Klinowski GO/rGO molecular models

Our paper “Lerf–Klinowski-type models of graphene oxide and reduced graphene oxide are robust in analyzing non-covalent functionalization with porphyrins” is online! This is excellent collaboration between CoopCat team, AMU team in Poznan and WUT in Warsaw.

Abstract:

Graphene-based nanohybrids are good candidates for various applications. However, graphene exhibits some unwanted features such as low solubility in an aqueous solution or tendency to aggregate, limiting its potential applications. On the contrary, its derivatives, such as graphene oxide (GO) and reduced graphene oxide (RGO), have excellent properties and can be easily produced in large quantities. GO/RGO nanohybrids with porphyrins were shown to possess great potential in the field of photocatalytic hydrogen production, pollutant photodegradation, optical sensing, or drug delivery. Despite the rapid progress in experimental research on the porphyrin-graphene hybrids some fundamental questions about the structures and the interaction between components in these systems still remain open. In this work, we combine detailed experimental and theoretical studies to investigate the nature of the interaction between the GO/RGO and two metal-free porphyrins 5,10,15,20-tetrakis(4-aminophenyl) porphyrin (TAPP) and 5,10,15,20-tetrakis(4-hydroxyphenyl) porphyrin (TPPH)]. The two porphyrins form stable nanohybrids with GO/RGO support, although both porphyrins exhibited a slightly higher affinity to RGO. We validated finite, Lerf–Klinowski-type (Lerf et al. in J Phys Chem B 102:4477, 1998) structural models of GO and RGO and successfully used them in ab initio absorption spectra simulations to track back the origin of experimentally observed spectral features. We also investigated the nature of low-lying excited states with high-level wavefunction-based methods and shown that states’ density becomes denser upon nanohybrid formation. The studied nanohybrids are non-emissive, and our study suggests that this is due to excited states that gain significant charge-transfer character. The presented efficient simulation protocol may ease the properties screening of new GO/RGO-nanohybrids.

Check online:

https://www.nature.com/articles/s41598-021-86880-1

Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Diformylfuran by Visible Light‐Driven Photocatalysis over In Situ Substrate‐Sensitized Titania

Our work done in collaboration with the group of Prof. JC Colmenares is out. Check how we used H-terminated clusters to get insights into chemical transformations of HMF at the TiO2(atanase) surface. Our approach involve state-of-the-art DLNO-CCSD(T) energy calculations and numerical partial Hessian evaluation for reliable IR and Raman spectra prediction.

“Selective Oxidation of 5‐Hydroxymethylfurfural to 2,5‐Diformylfuran by Visible Light‐Driven Photocatalysis over In Situ Substrate‐Sensitized Titania”

A. Khan, M. Goepel, A. Kubas, D. Łomot, W. Lisowski, D. Lisovytsky, A. Nowicka, J.C. Colmenares, R. Glaser
ChemSusChem, 2021, https://doi.org/10.1002/cssc.202002687

New work on flow hydrogenation is online!

Boosting the Performance of Nano-Ni Catalysts by Palladium Doping in Flow Hydrogenation of Sulcatone

Catalysts 2020, 10(11), 1267

The effect of Pd doping on nano-Ni catalyst hydrogenation aptitude in sulcatone (6-methyl-5-hepten-2-one) hydrogenation was investigated. Obtained results demonstrated that the addition of non-catalytic amounts of Pd to the surface of parent Ni catalyst improves the activity to the extent that it surpassed the activity of 2.16 wt% Pd catalyst (model catalyst) at optimal reaction conditions in the flow hydrogenation of an unsaturated ketone. Pd doping improves hydrogen activation on the catalyst, which was found to be a rate-limiting step using kinetic isotopic measurements and theoretical calculations.

CoopCat group seminar: Michał Tomza

mtomza_icfo

It is my pleasure to invite you to an online seminar of the Cooperative Catalysis Group. Tomorrow, on Friday, our guest will be the recipient of this year’s NCN scientific prize dr hab. Michał Tomza from the Faculty of Physics of the University of Warsaw.

Below please find the Zoom link and talk details.

Time: Oct 30, 2020 11:00 AM Warsaw
https://zoom.us/j/96570388483?pwd=c1BTV3pZcktTU0tUbmtEdFB0ejJUUT09
Meeting ID: 965 7038 8483
Passcode: 336789


Talk title: “Accurate ab initio quantum-chemical calculations for ultracold scattering experiments”

Abstract:
Hybrid systems of laser-cooled trapped ions and ultracold atoms combined in a single experimental setup have recently emerged as a new platform for fundamental research in quantum physics and chemistry [1]. Reaching the ultracold s-wave quantum regime has been one of the most critical challenges in this field for a long time. Unfortunately, the lowest attainable temperatures in experiments using the Paul ion trap are limited by the possible rf-field-induced heating related to the micromotion [2]. Recently, buffer gas cooling of a single ion in a Paul trap to the quantum regime of ion-atom collisions was realized, and a deviation from classical Langevin theory was observed by studying the spin-exchange dynamics, indicating quantum effects in the ion-atom collisions [3]. In my seminar, I will present how quantum chemical calculations of electronic structure and scattering dynamics can guide and explain quantum physics and chemistry experiments. In particular, I will describe how, in collaboration with experimental groups from Amsterdam [3], Stuttgart [4], and Freiburg, we have overcome the micromotion limitation. I will also discuss incoming applications, including first observation and application of magnetic Feshbach resonances, to control ultracold ion-atom collisions.

[1] Tomza et al, Rev. Mod. Phys. 91, 035001 (2019)
[2] Cetina et al., Phys. Rev. Lett. 109, 253201 (2012)
[3] Feldker et al, Nature Phys. 16, 413 (2020)
[4] Schmid et al, Phys. Rev. Lett. 120, 153401 (2018)

Group seminars

Each Friday CoopCat group holds on-line seminars during the coronavirus outbreak. Please let mail akubas@ichf.edu.pl if you would like to join us!

Upcoming seminar: Friday, 23.10.2020, 10 am
dr Dariusz Piekarski
“Insight into the Folding and Cooperative Multi‐Recognition Mechanism in Supramolecular Anion‐Binding Catalysis”

Recent seminar: Friday, 16.10.2020, 10 am
dr Michał Kochman

“Modeling solvent effects in the photophysics of organic molecules”

CoopCat group has new members!

Dr Michał Kochman and dr Dariusz Piekarski received PD2PI grants to carry out research in CoopCat group. Michał will look on trans-cis photoisomerization of retinoids using quantum chemical methods. Darek will focus on machine learning design of anion binding catalysts.

James Pogrebetsky started PhD project with us. He will work together with Aleksandra to develop new embedding scheme to represent metallic surfaces.