Check our latest paper on GO-porphyrins interface. Our contribution includes structure and spectra simulations, explanation of exp-observed peaks as well as charge-transfer study in the nanohybrid using high-level multireference methods (CASSCF/DLPNO-NEVPT2).

Interaction of Light with Non-Covalent Zinc Porphyrin-Graphene Oxide Nanohybrid

The present study explores the influence of graphene oxide (GO) on deactivation pathways of the excited states of zinc 5,10,15,20-tetrakis(4-(hydroxyphenyl) porphyrin (ZnTPPH). The interaction of light with free ZnTPPH molecules and with ZnTPPH molecules adsorbed on graphene oxide sheets was probed via UV-Vis spectroscopy, fluorescence spectroscopy, femtosecond pump–probe spectroscopy and nanosecond flash photolysis. Formation of the ground-state ZnTPPH-GO complex in solution was monitored by the red-shift of the porphyrin Soret absorption band. It was found that Stern−Volmer fluorescence quenching can be described in terms of two different quenching regimes depending on the GO concentration. In addition, our comprehensive analysis of the steady-state and time-resolved emission experiments led to the conclusion that the observed quenching was entirely attributable to a static mechanism. Laser flash photolysis showed that the triplet lifetime of the ZnTPPH was increased in the presence of GO from 174 µs to 292 µs, which is related to the decrease of the rate constant of a radiationless decay mechanism involving rotation of the peripheral hydroxyphenyl rings of the porphyrin. Femtosecond transient absorption spectroscopy demonstrated the presence of a fast photoinduced electron transfer from the singlet excited state of ZnTPPH to the GO sheets, as indicated by the formation of a porphyrin radical cation. Quantum chemical calculations were used to gain deeper insights into the nature of the electronically excited states in the ZnTPPH-GO complex.

Magda’s work in collaboration with Emil and Ania from R. Nowakowski group has been published!

Effect of unimodality and bimodality of Pd nanoparticles on the catalytic activity of Pd/SiO2 in the removal of diclofenac from water

In this work, we investigated the catalytic performance of uni- and bimodal Pd/SiO2 catalysts in the aqueous phase hydrodechlorination (HDC) of diclofenac – a very popular nonsteroidal anti-inflammatory drug. Unimodality and bimodality was confirmed by temperature-programmed hydride decomposition (TPHD) and TEM. The highest activity and 100% efficiency in batch and flow mode were observed for bimodal Pd NPs. This outstanding efficiency could be attributed to the close coexistence of small and large metal nanoparticles with different affinity to hydrogen and chloroorganic compound. The obtained results encourage discussion on the necessity to strive for perfect unimodal catalysts for the HDC processes.

We look for a talented PhD student to work on the development of novel embedding techniques to deal with metallic surfaces. Check our offer now!

Tuning Nano‐Nickel Catalyst Hydrogenation Aptitude by On‐the‐Fly Zirconium Doping
https://doi.org/10.1002/cctc.202000235

The effect of nano‐Ni catalyst post‐synthetic Zr‐modification on hydrogenation reaction of 6‐methyl‐5‐hepten‐2‐one was investigated in a fixed bed continuous‐flow micro‐reactor to produce fine chemicals. The catalytic performance revealed that Zr‐doping achieved by surface organometallic chemistry approach modifies the natural aptitude of nickel to hydrogenate C=C bond, since the addition of small quantities of zirconium significantly increased the amount of unsaturated and saturated alcohols formed in 6‐methyl‐5‐hepten‐2‐one hydrogenation. Quantum chemical calculations revealed a stronger interaction between Zr←O=C that promotes the formation of C=C semihydrogenation product and enhances the probability of complete hydrogenation. The on‐the‐fly strategy presented herein enables for rapid optimization and understanding of catalytic processes.

He will work on theory of reactivity at metallic surfaces

Gosia was the guest of Otokoclub.pl portal and gave an interview on the Nobel Prize in Chemistry 2007 (Gerhard Ertl).
See the interview (in PL only, sorry) under: http://otokoclub.pl/video_,355,wywiad-z-dr-malgorzata-zienkiewicz-machnik-o-nagrodzie-nobla-z-chemii-z-2007-r.html

The CoopCat team is now officially recognized at IPC PAS as Group 20: Cooperative Catalysis!

Marcin is a master student from Warsaw University of Technology. He will focus on enantioselective epoxidation of enones. Good luck Marcin!

Aleksandra will work on homogeneous catalysis problems, especially on non-linear effects. She will also contribute to our research in heterogeneous catalysis. Good luck Sasha!

Happy to announce new paper from our group:

Z-isomerization of retinoids through combination of monochromatic photoisomerization and metal catalysis

Catalytic Z-isomerization of retinoids to their thermodynamically less stable Z-isomer remains a challenge. In this report, we present a photochemical approach for the catalytic Z-isomerization of retinoids using monochromatic wavelength UV irradiation treatment. We have developed a straightforward approach for the synthesis of Z-retinoids in high yield, overcoming common obstacles normally associated with their synthesis. Calculations based on density functional theory (DFT) have allowed us to correlate the experimentally observed Z-isomer distribution of retinoids with the energies of chemically important intermediates, which include ground- and excited-state potential energy surfaces. We also demonstrate the application of the current method by synthesizing gram-scale quantities of 9-cis-retinyl acetate 9Z-a. Operational simplicity and gram-scale ability make this chemistry a very practical solution to the problem of Z-isomer retinoid synthesis.

Read more: https://pubs.rsc.org/en/content/articlelanding/2019/ob/c9ob01645g