Supramolecular Organic and Organometallic Chemistry Centre

Abstract
The aim of the present project proposal is the synthesis, structural characterization and investigation of the optical properties (luminescence) of some new 4-arylidene-5(4H)- imidazolones, -oxazolones, -thiazolones, -selenazolones and their late d metal complexes (Ru, Ir, Pd, Pt, Ag, Au). The biological (antioxidant and antibacterial) properties of selected new compounds will be also investigated. Our studies envisage appropriate methods for controlling the molecular structure of the respective species and to promote a fine tuning of the metal-ligand interactions by changing the electronic environment about the chalcogen and/or the metal centre. We intend to find solutions for optimizing the conditions for a better molecular structure / biological activity relation. All the new compounds will be investigated by spectroscopic methods: multinuclear NMR spectroscopy, electronic spectroscopy, mass spectrometry, single-crystal X-ray diffraction, IR, UV-VIS spectroscopy and luminescent measurements. The proposed research activities will be focused on:

• design of 4-arylidene-5(4H)-imidazolone, -oxazolone, -thiazolone, and -selenazolone scaffolds;
• design of new organochalcogen compounds;
• synthesis of new transition metals complexes having good photophysical behaviour (Ru, Ir, Pd, Pt, Ag, Au);
• structural investigations;
• measurements of photophysical properties of representative metal complexes;
• investigation of the redox activity of organoselenides and antibacterial activity of metal complexes

Results 2020-2022

New diorganochalcogen(II) and diorganodichalcogen(I) species containing oxazolone, thiazolone and imidazolone fragments incorporated to their skeleton were synthetized and their ability to coordinate to silver(I) and gold(I) salts was study. The electron donor properties of all species were investigated by UV-Vis absorption in solution, strong absorption bands with large extension coefficients observed were attributed to the intra-ligand charge transfer (ICT) in all species and the redox GPx-like activity of heteroleptic diorganoselenides(II) was investigated. Homoleptic and heteroleptic diorganomercury(II) species containing oxazolone fragments were synthetised and were used in transmetalation reactions for the preparation of Au(III) and Ru(II) species.
For the identification and characterization of the compounds multinuclear NMR (¹H, ¹³C{¹H}, ¹⁹F{¹H}, ³¹P{¹H}, ⁷⁷Se{¹H}, when appropriate) spectroscopy, IR spectroscopy, elemental analysis, UV-Vis absorption spectroscopy, molar conductivities measurements, mass spectrometry and single-crystal X-ray diffraction were used.

Summary of the project results November 2020 - October 2022

• New homoleptic and heteroleptic diorganochalcogen(II), diorganodiselenide(I) and organomercury compounds, containing 4-arylidene-5(4H)-imidazolone, -oxazolone and -thiazolone scaffolds, were prepared and structurally characterized;
  
• New transition metals complexes (Pd, Au) were synthesized and structurally investigated.
  
• Silver(I) complexes containing homoleptic and heteroleptic diorganochalcogen(II) ligands were prepared, characterized in solution and in solid state and their optical properties were investigated.
  
  

Publications

1. Silver(I) complexes containing heteroleptic diorganochalcogen(II) ligands,
   R. A. Butuza, D. Dumitraş, C. Bohan and A. Pop,
   New J. Chem., 2023, 47, 2202.
   DOI:10.1039/D2NJ05472H
   
   
2. 2. Synthesis of Bis(amino acids) Containing the Styryl-cyclobutane Core by Photosensitized [2+2]-Cross-cycloaddition of Allylidene-5(4H)-oxazolones,
   S. Sierra, D. Dalmau,J. V. Alegre-Requena, A. Pop, C. Silvestru, M. L. Marin, F. Bosca and E. P. Urriolabeitia,
   Int. J. Mol. Sci., 2023, 24, 7583.
   DOI:10.3390/ijms24087583
   
   
3. Metal Complexes Containing Homoleptic Diorganoselenium(II) Ligands: Synthesis, Characterization and Investigation of Optical Properties,
   D. Dumitraş, E. Gal, C. Silvestru, A. Pop,
   Molecules, 2024, 29(4), 792.
   DOI:10.3390/molecules29040792
   
   

Conferences

1. Synthesis and structural characterization of new heteroleptic diorganochalcogen(II) compounds,
   C. Bohan, D. Dumitraş and Alexandra Pop,
   at 17^th International Conference Students for Students, April 21-24, 2021, Cluj-Napoca, Romania (oral presentation).
   
   
2. Sinteza și caracterizarea structurală a unor noi compuși heteroleptici calcogen(II) organici,
   C. Bohan, D. Dumitraş and Alexandra Pop,
   at Sesiunea de Comunicări Științifice Studențești, ediția a XVI-a, May 28-29, 2021, București, Romania (oral presentation).
   
   
3. Synthesis and structural characterization of new diorganochalcogen(II) compounds,
   C. Bohan, and Alexandra Pop,
   at 18^th International Conference Students for Students, April 6-10, 2022, Cluj-Napoca, Romania (oral presentation).
   
   
4. Synthesis, Structural Characterization and Reactivity of New Organoselenium Compounds Containing 4-aryliden-5(4H)-oxazolones,
   D. Dumitraş, A. Silvestru and Alexandra Pop,
   at Conferința Națională de Chimie, October 4-7, 2022, Căciulata, Romania (poster presentation).
   
   
5. New organoselenium compounds - Synthesis, structural characterization and reactivity,
   Alexandra Pop,
   at 15^th International Conference on the Chemistry of Se & Te (ICCST-15), November, 28 - December, 2, 2022, Florianopolis, Brazil (flash presentation).
   
   

Contributions to BSc. and Master Theses

1. Dumitraş Darius - Sinteza, caracterizarea structurală și reactivitatea unor noi liganzi heteroleptici seleniu-organici, iulie 2021
   
   
2. Ana-Maria Hodorogea - Complecşi ai zincului cu liganzi seleniu-organici – potențiali precursori pentru ZnSe, iulie 2021
   
   
3. Cosmina Bohan - Sinteza și caracterizarea structurală a unor noi compuşi calcogen-organici, iulie 2022
   
   

Reports

• The yearly scientific reports containing experimental details of unpublished compounds data can be provided for project evaluation purposes only. To obtain copies of these reports please contact Lect. Dr. Alexandra Pop by e-mail at alexandra.m.pop@ubbcluj.ro.