New Benzothiazole Based Copper(II) Hydrazone Schiff Base Complexes for Selective and Environmentally Friendly Oxidation of Benzylic Alcohols: The Importance of the Bimetallic Species Tuned by the Choice of the Counterion

Aleksandra Bocian , Adam Gorczyński , Damian Marcinkowski , Samanta Witomska , Maciej Kubicki , Paulina Mech , Małgorzata Bogunia , Jakub Brzeski , Mariusz Makowski , Piotr Pawluć , Violetta Patroniak

Abstract

Green and sustainable chemistry approaches necessitate an ongoing investigation towards new, environmentally benign and selective catalysts. We have thus prepared a new benzothiazole-scaffolded hydrazone Schiff base ligand L and coordinated it with copper(II) ions leading to five different complexes, the form of which in the solid state is counterion-dependent. Nitrate, chloride and triflate anions lead to monometallic species, whereas utilization of sulfates and tetrafluoroborates is responsible for the formation of bimetallic assemblies. The catalytic efficiency of synthesized compounds was shown in Cu-TEMPO (2,2,6,6-tetramethyl-l-piperidinoxyl) aerobic oxidation of activated alcohols resulting in good to excellent conversions and 100% selectivity to form the corresponding aldehydes. Considering the experimental results and Density Functional Theory calculations we propose two most plausible reaction mechanisms that further corroborate the enhanced activity of bimetallic species. It appears that the tridentate character of the ligand sacrifices some of the overall catalytic efficiency for the selectivity of the process. Aqueous reaction medium, low catalyst loading, air as oxidant and exclusive oxidative selectivity render these CuII complexes promising candidates for further improvement.
Author Aleksandra Bocian - Adam Mickiewicz University in Poznań (UAM)
Aleksandra Bocian,,
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, Adam Gorczyński - Adam Mickiewicz University in Poznań (UAM)
Adam Gorczyński,,
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, Damian Marcinkowski (PE / DAEQA)
Damian Marcinkowski,,
- Department of Agricultural Engineering and Quality Analysis
, Samanta Witomska - Adam Mickiewicz University in Poznań (UAM)
Samanta Witomska,,
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, Maciej Kubicki - Adam Mickiewicz University in Poznań (UAM)
Maciej Kubicki,,
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, Paulina Mech - University of Gdańsk (UG)
Paulina Mech,,
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, Małgorzata Bogunia - University of Gdańsk (UG)
Małgorzata Bogunia,,
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, Jakub Brzeski - University of Gdańsk (UG)
Jakub Brzeski,,
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, Mariusz Makowski - University of Gdańsk (UG)
Mariusz Makowski,,
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, Piotr Pawluć - Adam Mickiewicz University in Poznań (UAM)
Piotr Pawluć,,
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et al.`
Journal seriesJournal of Molecular Liquids, ISSN 0167-7322, e-ISSN 1873-3166, (N/A 100 pkt)
Issue year2020
Vol302
Pages1-9
Publication size in sheets0.5
Article number112590
Keywords in EnglishCopper, Coordination Compounds, Complexes, Schiff Base, Hydrazone, Alcohol Oxidation, Density Functional Theory (DFT), Green Chemistry, Environmental Chemistry
ASJC Classification1606 Physical and Theoretical Chemistry; 1607 Spectroscopy; 2504 Electronic, Optical and Magnetic Materials; 2505 Materials Chemistry; 3104 Condensed Matter Physics; 3107 Atomic and Molecular Physics, and Optics
DOIDOI:10.1016/j.molliq.2020.112590
Languageen angielski
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Bocian_Gorczynska_Marcinkowski_Witomska_Kubicki_Mech_Bagunia_Brzeski_Makowski_Pawluc_Patroniak_New_Benzothiazole_Based_Cooper.pdf 1,08 MB
Score (nominal)100
Score sourcejournalList
Publication indicators Scopus SNIP (Source Normalised Impact per Paper): 2018 = 1.275; WoS Impact Factor: 2018 = 4.561 (2) - 2018=4.136 (5)
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