Green chemistry is at the forefront of current developments of various research areas in chemistry. One of its major objectives is to develop efficient solvent-free and low-energy preparative methods for various classes of existing and new chemicals.
The feasibility of this green-chemistry concept will be demonstrated on the synthesis of organopalladium complexes and the majority of synthetic steps in this project will be performed in the solid state using methods of accelerated aging and mechanochemistry. The first mechanosynthesis of organopalladium compounds via C–H bond activation, which is of exceptional importance in organic synthetic chemistry, by palladium(II) acetate has been recently reported by our group.
Within this project we propose to develop and implement solid-state methods for the synthesis of a series of cyclopalladated sodium salts of aromatic azo compounds. Interest in such organopalladium complexes with conjugated C=C and N=N bonds arises from their strong light absorption and emission in the visible and near infrared regions, which qualifies them as good candidates for biomolecular labels or cellular dyes.
Their optical properties can be modulated by an appropriate selection of ancillary ligands or by varying the substituents on the azo ligand. In this regard, the affinity of these complexes to target amino acids, short peptides and nucleobases will be studied by UV-vis and fluorescence spectroscopies. Particular attention will be given to Pd(II) compounds which absorb and fluoresce in the near-infrared region due to their low phototoxicity to cells and low autofluorescence of biological samples in this spectral region. Consequently, an additional benefit of this project will be a series of new chromogenic and fluorogenic room-temperature chemosensors.
The solid-state structures of the products will be resolved by X-ray diffraction studies, NMR, Raman and IR spectroscopies. The structural features of complexes and their stability in solution will be evaluated by NMR spectroscopy along with the ESI mass spectrometry. The direct insight into the reaction dynamics and mechanism of formation of organopalladium complexes in the solid state will be studied in real time by in situ monitoring of the reactions using Raman spectroscopy, and in the solution by UV-vis and NMR spectroscopy along with the ESI mass spectrometry.
The optical characteristics of complexes will be evaluated by UV-vis and fluorescence spectroscopies in the solid state and solution. The experimental results will be rationalized by theoretical studies in order to explain isomerism of complexes, the nature of their electronic transitions and to assign the Raman and IR spectra as well as to obtain additional support for the mechanism of formation of the complexes.
Suradnici na projektu
- prof. Janez Plavec
- Dr. Marina Juribašić Kulcsar
- Dr. Ana Budimir
- Dr. Krunoslav Juraić
- Alen Bjelopetrović, mag. chem.
- Dajana Barišić, mag. chem.
Publikacije na projektu
- Bjelopetrović, A.; Robić, M.; Halasz, I.; Babić, D.; Juribašić Kulcsar, M.*; Ćurić, M.* "Facile Mechanochemical Anion Substitution in Cyclopalladated Azo-benzenes."Organometallics 2019, rad prihvaćen za objavljivanje. (IF 4.10, Q1).
- Bjelopetrović, A.; Lukin, S.; Halasz, I.; Užarević, K.; Đilović, I.; Barišić, D.; Budimir, A.; Juribašić Kulcsar, M.*;Ćurić, M.* "Mechanism of Mechanochemical C-H Bond Activation in an Azobenzene Substrate by Pd(II) Catalysts." Chemistry-A European Journal 2018, 24, 10672 ("Hot Paper" istaknut na unutrašnjoj naslovnici i u ChemViews, magazinu udruženja kemijskih društava Europe). (IF 5.16, Q1). https://onlinelibrary.wiley.com/doi/10.1002/chem.201803520 https://www.chemistryviews.org/details/ezine/110847/Insight_into_Mechanochemical_CH_Bond_Activation.html
- Juribašić Kulcsar, M.*; Halasz, I.; Budimir, A.; Užarević, K.; Lukin, S.; Monas, A.; Emmerling, F.; Plavec, J.; Ćurić, M.* "Reversible Gas-Solid Ammonia N–H Bond Activation Mediated by an Organopalladium Complex. "Inorganic Chemistry 2017, 56, 5342. (IF 4.85, Q1)
- Monas, A.; Užarević, K.; Halasz, I.; Juribašić Kulcsar, M.*; Ćurić, M.* "Vapour-Induced Solid-State C–H bond Activation for the Clean Synthesis of an Organopalladium Biothiol Sensor." Chemical Communications 2016, 52, 12960 (članak istaknut na stražnjoj naslovnici). (IF 6.164, Q1) https://pubs.rsc.org/en/content/articlepdf/2016/cc/c6cc06062e