The “Periodic Table” of 1-methylbenzotriazole: Zinc(II) Complexes
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Published:2023-08-29
Issue:9
Volume:11
Page:356
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ISSN:2304-6740
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Container-title:Inorganics
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language:en
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Short-container-title:Inorganics
Author:
Stamou Christina1, Barouni Eleftheria1, Plakatouras John C.2ORCID, Sigalas Michael M.3, Raptopoulou Catherine P.4ORCID, Psycharis Vassilis4, Bakalbassis Evangelos G.5, Perlepes Spyros P.16
Affiliation:
1. Department of Chemistry, University of Patras, 26504 Patras, Greece 2. Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece 3. Department of Materials Science, University of Patras, 26504 Patras, Greece 4. Institute of Nanoscience and Nanotechnology, NCSR “Demokritos”, 15310 Aghia Paraskevi Attikis, Greece 5. Department of Chemistry, Aristotle University of Thessaloniki, University Campus, 54124 Thessaloniki, Greece 6. Institute of Chemical Engineering Sciences, Foundation for Research and Technology (FORTH/ICE-HT), Platani, P.O. Box 1414, 26504 Patras, Greece
Abstract
In an attempt to fill in the empty Zn position in the “Periodic Table” of 1-methylbenzotriazole (Mebta), reactions between Zn(II) sources and this ligand were carried out. The detailed synthetic studies provided access to complexes [ZnX2(Mebta)2] (X = Cl, 1; X = Br, 3; X = I, 4), (MebtaH)2[ZnCl4] (2), tet-[Zn(NO3)2(Mebta)2] (5), oct-[Zn(NO3)2(Mebta)2] (6), and [Zn(Mebta)4](Y)2 [Y = ClO4, 7; Y = PF6, 8]. Solid-state thermal decomposition of 2 leads to 1 in quantitative yield. The structures of 3, 4, 5, 6, and 7 were determined by single-crystal crystallography. The structures of the remaining complexes were proposed based on spectroscopic evidence. In all compounds, Mebta behaves as monodentate ligand using the nitrogen of the position 3 as donor. Complexes 1–4, 7, and 8 are tetrahedral. Complexes 5 and 6 are isostoichiometric and their preparation in pure forms depends on the reaction conditions; in the former the ZnII atom has a tetrahedral geometry, whereas in the latter the metal ion is octahedral. This case of rare isomerism arises from the monodentate (in 5) vs. bidentate (in 6) coordination of the nitrato groups. Extensive π–π stacking interactions and non-classical H bonds build interesting 3D architectures in the structurally characterized complexes. The compounds were characterized by IR, far-IR, and Raman spectroscopies in the solid state, and the data were interpreted in terms of the structures (known or proposed) of the complexes and the coordination modes of the organic and inorganic ligands involved. The solid-state structures of the complexes are not retained in solution, as proven by NMR (1H, 13C[1H]) spectroscopy and molar conductivity data. The thermal decomposition study of 1 and 3 leads to stable intermediates with 1:1 stoichiometry, i.e., ZnX2(Mebta). Based on far-IR spectra, polymeric tetrahedral structures are possible with simultaneous presence of terminal and bridging X− groups. Liquid-phase ab initio (MP2) and gas-phase DFT calculations, performed on Mebta and the nitrato complexes, respectively, shed light on the tendency of Mebta for N3-coordination, and the existence and relative stabilities of 5 and 6.
Funder
Special Account of the NCSR “Demokritos”
Subject
Inorganic Chemistry
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