OPEN Repository

Welcome to OPEN - the Repository of Open Scientific Publications, run by the Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, previously operating as the CeON Repository. The Repository enables Polish researchers from all fields to openly share their articles, books, conference materials, reports, doctoral theses, and other scientific texts.

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Recent Submissions

Strongly Polarized π-Extended 1,4-Dihydropyrrolo[3,2-b]pyrroles Fused with Tetrazolo[1,5-a]quinolines
(ACS Publications, 2024) Teimouri, Mohammad B.; Deperasińska, Irena; Rammo, Matt; Banasiewicz, Marzena; Stark, Charles W.; Dobrzycki, Łukasz; Cyrański, Michał K.; Rebane, Aleksander; Gryko, Daniel T.; Institute of Organic Chemistry, Polish Academy of Sciences; Institute of Physics, Polish Academy of Sciences; Faculty of Chemistry, Kharazmi University, Tehran, Iran; National Institute for Chemical Physics and Biophysics, Tallinn, Estonia; Faculty of Chemistry, University of Warsaw; Department of Physics, Montana State University, Montana, United States
A straightforward route to 1,4-dihydropyrrolo[3,2-b]pyrroles comprised of two electron-withdrawing quinoline or tetrazolo[1,5-a]quinoline scaffolds has been developed. The versatile multicomponent reaction affording 1,4-dihydropyrrolo[3,2-b]pyrroles combined with intramolecular direct arylation enables assembly of these products in just three steps from anilines with overall yields exceeding 30%. The planarized, ladder-type heteroacenes possess up to 14 conjugated rings. These nominally quadrupolar materials exhibit efficient fluorescence with wavelengths spanning most of the visible spectrum from green−yellow for the dyes possessing biaryl bridges and orange−red for the fully fused systems. In many cases, the fluorescence quantum yields are large, the solvatofluorochromic effects are strong, and the fluorescence is maintained even in crystalline state. Analysis of the electronic structure of these molecular architectures using quantum chemical methods suggests that the character and position of the flanking heterocycle determine the shape of HOMO and LUMO and their extension to N-aryl substituents, influencing the values of molar absorption coefficient. An experimental study of the two-photon absorption (2PA) properties has revealed that it occurs in the 700−800 nm range with apparent deviation from the Laporte parity selection rule, which may be attributed to Hertzberg−Teller contribution to vibronically allowed 2PA transition.
Excited-state symmetry breaking in quadrupolar pull–push–pull molecules: dicyanovinyl vs. cyanophenyl acceptors
(Royal Society of Chemistry, 2023) Verma, Pragya; Tasior, Mariusz; Roy, Palas; Meech, Stephen R.; Gryko, Daniel T.; Vauthey, Eric; Department of Physical Chemistry, University of Geneva, Switzerland; Institute of Organic Chemistry, Polish Academy of Sciences; School of Chemistry, University of East Anglia, UK
A significant number of quadrupolar dyes behave as their dipolar analogues when photoexcited in polar environments. This is due to the occurrence of excited-state symmetry breaking (ES-SB), upon which the electronic excitation, initially distributed over the whole molecule, localises preferentially on one side. Here, we investigate the ES-SB properties of two A–D–A dyes, consisting of a pyrrolo-pyrrole donor (D) and either cyanophenyl or dicyanovinyl acceptors (A). For this, we use time-resolved vibrational spectroscopy, comparing IR absorption and femtosecond stimulated Raman spectroscopies. Although dicyanovinyl is a stronger electron-withdrawing group, ES-SB is not observed with the dicyanovinyl-based dye even in highly polar media, whereas it already takes place in weakly polar solvents with dyes containing cyanophenyl accepting groups. This difference is attributed to the large electronic coupling between the D–A branches in the former dye, whose loss upon symmetry breaking cannot be counterbalanced by a gain in solvation energy. Comparison with analogues of the cyanophenyl-based dye containing different spacers reveals that interbranch coupling does not so much depend on the distance between the D–A subunits than on the nature of the spacer. We show that transient Raman spectra probe different modes of these centrosymmetric molecules but are consistent with the transient IR data. However, lifetime broadening of the Raman bands, probably due to the resonance enhancement, may limit the application of this technique for monitoring ES-SB.
The magic of biaryl linkers: the electronic coupling through them defines the propensity for excited-state symmetry breaking in quadrupolar acceptor–donor–acceptor fluorophores
(Royal Society of Chemistry, 2023) Clark, John A.; Kusy, Damian; Vakuliuk, Olena; Krzeszewski, Maciej; Kochanowski, Krzysztof J.; Koszarna, Beata; O'Mari, Omar; Jacquemin, Denis; Gryko, Daniel T.; Vullev, Valentine I.; Department of Bioengineering, University of California, Riverside, California; Institute of Organic Chemistry, Polish Academy of Sciences; Nantes Universite, CNRS, France; Institut Universitaire de France (IUF); Department of Chemistry, University of California; Department of Biochemistry, University of California; Materials Science and Engineering Program, University of California
Charge transfer (CT) is key for molecular photonics, governing the optical properties of chromophores comprising electron-rich and electron-deficient components. In hotoexcited dyes with an acceptor–donor–acceptor or donor–acceptor–donor architecture, CT breaks their quadrupolar symmetry and yields dipolar structures manifesting pronounced solvatochromism. Herein, we explore the effects of electronic coupling through biaryl linkers on the excited-state symmetry breaking of such hybrid dyes composed of an electron-rich core, i.e., 1,4-dihydropyrrolo[3,2-b]pyrrole (DHPP), and pyrene substituents that can act as electron acceptors. Experimental and theoretical studies reveal that strengthening the donor–acceptor electronic coupling decreases the CT rates and the propensity for symmetry breaking. We ascribe this unexpected result to effects of electronic coupling on the CT thermodynamics, which in its turn affects the CT kinetics. In cases of intermediate electronic coupling, the pyrene-DHPP conjugates produce fluorescence spectra, spreading over the whole visible range, that in addition to the broad CT emission, show bands from the radiative deactivation of the locally excited states of the donor and the acceptors. Because the radiative deactivation of the low-lying CT states is distinctly slow, fluorescence from upper locally excited states emerge leading to the observed anti-Kasha behaviour. As a result, these dyes exhibit white fluorescence. In addition to demonstrating the multifaceted nature of the effects of electronic coupling on CT dynamics, these chromophores can act as broad-band light sources with practical importance for imaging and photonics.
Unprecedented 1,2-Aryl Shift Accompanying Double Alkyne Benzannulation
(Wiley, 2023) Sanil, Gana; Krzeszewski, Maciej; Chaładaj, Wojciech; Danikiewicz, Witold; Knysh, Iryna; Dobrzycki, Łukasz; Staszewska-Krajewska, Olga; Cyrański, Michał; Jacquemin, Denis; Gryko, Daniel T.; Institute of Organic Chemistry, Polish Academy of Sciences; Nantes Université, CNRS, France; Faculty of Chemistry, University of Warsaw; Institut Universitaire de France (IUF)
The tandem intramolecular hydroarylation of alkynes accompanied by a 1,2-aryl shift is described. Harnessing the unique electron-rich character of 1,4-dihydropyrrolo[3,2-b]pyrrole scaffold, we demonstrate that the hydroarylation of alkynes proceeds at the already occupied positions 2 and 5 leading to a 1,2-aryl shift. Remarkably, the reaction proceeds only in the presence of cationic gold catalyst, and it leads to heretofore unknown π-expanded, centrosymmetric pyrrolo[3,2-b]pyrroles. The utility is verified in the preparation of 13 products that bear six conjugated rings. The observed compatibility with various functional groups allows for increased tunability with regard to the photophysical properties as well as providing sites for further functionalization. Computational studies of the reaction mechanism revealed that the formation of the sixmembered rings accompanied with a 1,2-aryl shift is both kinetically and thermodynamically favourable over plausible formation of products containing 7-membered rings. Steady-state UV/visible spectroscopy reveals that upon photoexcitation, the prepared Sshaped N-doped nanographenes undergo mostly radiative relaxation leading to large fluorescence quantum yields. Their optical properties are rationalized through time-dependent density functional theory calculations. We anticipate that this chemistry will empower the creation of new materials with various functionalities.
Biomimetic Fe–Cu Prophyrrole Aerogel Electrocatalyst for Oxygen Reduction Reaction
(American Chemical Society, 2023) Persky, Yeela; Kielesiński, Łukasz; Reddy, Samala Nagaprasad; Zion, Noam; Friedman, Ariel; Honig, Hilah C.; Koszarna, Beata; Zachman, Michael J.; Grinberg, Ilya; Gryko, Daniel T.; Elbaz, Lior; Chemistry Department, Bar-Ilan Center for Nanotechnology and Advanced Materials, Bar-Ilan University, Israel; Institute of Organic Chemistry, Polish Academy of Sciences; Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, United States
The development of bioinspired catalysts for oxygen reduction reaction is one of the most prominent pathways in the search for active materials to replace Pt-based catalysts in fuel cells. Herein, we report innovative bioinspired catalysts using a directed synthetic pathway to create adjacent Cu and Fe sites. This catalyst is composed of a covalent 3D framework in an aerogel form. Aerogels are high surface area and porous hierarchical structures that can allow the formation of ultrahigh active site density and optimized mass transport of reactants and products to and from the catalytic sites. The aerogel-based catalyst exhibits high performance in a half-cell in 0.1 M KOH, with an onset potential of 0.94 V vs RHE and half-wave potential of E1/2 = 0.80 V vs RHE, high selectivity toward the four-electron reduction of oxygen to hydroxide anions, and high durability. These results are well-translated to the anion exchange membrane fuel cell (AEMFC), reaching an open circuit potential of 0.97 V and iR-corrected peak power density of 0.51 W cm–2. Based on density functional theory calculations, the improved activity relative to the Fe-porphyrin and Cu-corrole is ascribed to the effect of the extended carbon network and the proximity of the metal sites.