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Bordoni S, Tarroni R, Monari M, Cerini S, Battaglia F, Micheletti G, Boga C, Drius G. Ru-Controlled Thymine Tautomerization Frozen by a k 1(O)-, k 2(N,O)-Metallacycle: An Experimental and Theoretical Approach. Molecules 2023; 28:molecules28103983. [PMID: 37241724 DOI: 10.3390/molecules28103983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 05/01/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
The reaction of mer-(Ru(H)2(CO)(PPh3)3) (1) with one equivalent of thymine acetic acid (THAcH) unexpectedly produces the macrocyclic dimer k1(O), k2(N,O)-(Ru(CO)(PPh3)2THAc)2 (4) and, concomitantly, the doubly coordinated species k1(O), k2(O,O)-(Ru(CO)(PPh3)2THAc) (5). The reaction promptly forms a complicated mixture of Ru-coordinated mononuclear species. With the aim of shedding some light in this context, two plausible reaction paths were proposed by attributing the isolated or spectroscopically intercepted intermediates on the basis of DFT-calculated energetic considerations. The cleavage of the sterically demanding equatorial phosphine in the mer-species releases enough energy to enable self-aggregation, producing the stable, symmetric 14-membered binuclear macrocycle of 4. The k1-acetate iminol (C=N-OH) unit of the mer-tautomer k1(O)-(Ru(CO)(PPh3)2(THAc)) (2) likely exhibits a stronger nucleophilic aptitude than the prevalent N(H)-C(O) amido species, thus accomplishing extra stabilization through concomitant k2(N,O)-thymine heteroleptic side-chelation. Furthermore, both the ESI-Ms and IR simulation spectra validated the related dimeric arrangement in solution, in agreement with the X-ray determination of the structure. The latter showed tautomerization to the iminol form. The 1H NMR spectra in chlorinated solvents of the kinetic mixture showed the simultaneous presence of 4 and the doubly coordinated 5, in rather similar amounts. THAcH added in excess preferentially reacts with 2 or trans-k2(O,O)-(RuH(CO)(PPh3)2THAc) (3) rather than attacking the starting Complex 1, promptly forming the species of 5. The proposed reaction paths were inferred by spectroscopically monitoring the intermediate species, for which the results were strongly dependent on the of conditions the reaction (stoichiometry, solvent polarity, time, and the concentration of the mixture). The selected mechanism proved to be more reliable, due to the final dimeric product stereochemistry.
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Affiliation(s)
- Silvia Bordoni
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
- Health Sciences and Technologies Interdepartmental Center for Industrial Research (CIRI SDV), University of Bologna, 40126 Bologna, Italy
| | - Riccardo Tarroni
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Magda Monari
- Department of Chemistry 'Giacomo Ciamician', Alma Mater Studiorum, Università di Bologna, Via Selmi 2, 40126 Bologna, Italy
| | - Stefano Cerini
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Fabio Battaglia
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Gabriele Micheletti
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Carla Boga
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Giacomo Drius
- Department of Industrial Chemistry 'Toso Montanari', Alma Mater Studiorum, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
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Prabhu Kumar K, Vasantha Kumar B, Kumar PR, Butcher RJ, Vivek H, Suchetan P, Revanasiddappa H, Foro S. Synthesis, characterization, CT‐DNA binding and docking studies of novel selenated ligands and their palladium complexes. Appl Organomet Chem 2020. [DOI: 10.1002/aoc.5634] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- K.M. Prabhu Kumar
- Department of Studies and Research in ChemistryTumkur University Tumkur Karnataka 572 103 India
| | - B.C. Vasantha Kumar
- Department of Studies in ChemistryUniversity of Mysore Mysuru Karnataka 570 006 India
| | - P. Raghavendra Kumar
- Department of Studies and Research in ChemistryTumkur University Tumkur Karnataka 572 103 India
| | | | - H.K. Vivek
- Faculty of Natural SciencesAdichunchanagiri University B. G. Ngara Mandya Karnataka India
| | - P.A. Suchetan
- Department of Studies and Research in ChemistryTumkur University Tumkur Karnataka 572 103 India
| | - H.D. Revanasiddappa
- Department of Studies in ChemistryUniversity of Mysore Mysuru Karnataka 570 006 India
| | - Sabine Foro
- Institute of Materials ScienceDarmstadt University of Technology Petersenstr. 23 D‐64287 Darmstadt Germany
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