dc.contributor.author | Kitos, Alexandros A. | en |
dc.contributor.author | Efthymiou, Constantinos G. | en |
dc.contributor.author | Manos, Manolis J. | en |
dc.contributor.author | Tasiopoulos, Anastasios J. | en |
dc.contributor.author | Nastopoulos, Vassilios | en |
dc.contributor.author | Escuer, Albert | en |
dc.contributor.author | Perlepes, Spyros P. | en |
dc.creator | Kitos, Alexandros A. | en |
dc.creator | Efthymiou, Constantinos G. | en |
dc.creator | Manos, Manolis J. | en |
dc.creator | Tasiopoulos, Anastasios J. | en |
dc.creator | Nastopoulos, Vassilios | en |
dc.creator | Escuer, Albert | en |
dc.creator | Perlepes, Spyros P. | en |
dc.date.accessioned | 2019-11-21T06:19:57Z | |
dc.date.available | 2019-11-21T06:19:57Z | |
dc.date.issued | 2016 | |
dc.identifier.issn | 1477-9226 | |
dc.identifier.uri | http://gnosis.library.ucy.ac.cy/handle/7/55682 | |
dc.description.abstract | The reactions of various copper(ii) sources with 2-acetylpyridine, (py)(me)CO, and 2-benzoylpyridine, (py)(ph)CO, under strongly basic conditions have been studied and novel ligand transformations have been discovered. Reaction of Cu(ClO4)2·6H2O and (py)(me)CO in the presence of NBu4nOMe (1 : 1 : 1) in CHCl3 gave a mixture of [Cu2Cl2(HLA)2](ClO4)2 (1) and [Cu2Cl2(LB)2(ClO4)2] (2), where HLA is 3-hydroxy-1,3-di(pyridin-2-yl)-butane-1-one and LB is the zwitterionic-type ligand 3-hydroxy-1-methyl-3-(pyridin-2-yl)-3H-indolizin-4-ium. The ligand HLA is formed through an aldol reaction-type mechanism, while the formation of LB takes place via an intramolecular nucleophilic attack of the remote 2-pyridyl nitrogen atom on the positive carbonyl carbon of HLA, after the transformation of the latter through deprotonation and dehydration. The CuII ions in 1 are bridged by two 2.1111 HLA ligands resulting in a long CuII⋯CuII distance (5.338 Å) | en |
dc.description.abstract | the metal ions in 2 are triply bridged by the alkoxide oxygen atoms of the two 2.21 LB ligands and one 2.1100 perchlorato group. The absence of α-hydrogens in (py)(ph)CO leads the reactivity of this ligand in the presence of CuII to different pathways. The Cu(ClO4)2·6H2O/(py)(ph)CO/NBu4nOMe reaction mixture in MeOH/H2O (25 : 1 v/v) gave the dinuclear cationic complex [Cu2{(py)(ph)CO}2(LC)2](ClO4)2 (3), where LC- is the anion of (methoxy)(phenyl)(pyridin-2-yl)methanol formed in situ via the nucleophilic addition of MeO- to the carbonyl carbon of (py)(ph)CO upon CuII coordination. The CuII ions in the cation are doubly bridged by the deprotonated oxygen atoms of the two LC- ligands. Replacement of Cu(ClO4)2·6H2O with Cu(NO3)2·3H2O and NBu4nOMe with NMe4OH and the decrease of the H2O concentration in the above reaction system yielded the tetranuclear coordination cluster [Cu4(OMe)2(NO3)4{(py)(ph)CO}2(LC)2] (4). The CuII centres in this complex define a parallelogram. Two parallel sides of the parallelogram are each supported by deprotonated oxygen atoms belonging to a 2.21 LC- ligand and a 2.2 MeO- group. The metal ions that define each of the other two sides are singly bridged by an oxygen atom of a 2.210 nitrato group. No bridging exists between the CuII ions that define the two diagonals of the parallelogram. Replacement of MeOH with EtOH in the reaction system that gave 4 resulted in the dinuclear complex [Cu2(NO3)2(LD)2)(EtOH)] (5), LD- being the anion of (ethoxy)(phenyl)(pyridin-2-yl)methanol. The CuII ions are doubly bridged by the alkoxide oxygen atoms of the two 2.21 LD- ligands. The 1 : 1 : 1 Cu(NO3)2·3H2O/(py)(ph)CO/NMe4OH reaction system in CH3NO2 gave the dinuclear complex [Cu2(NO3)2(LE)2] (6), where LE- is the anion of 2-nitro-1-phenyl-1-(pyridin-2-yl)ethanol. The OH- ion abstracts one of the methyl hydrogens of CH3NO2, and once the carbanion -:CH2NO2 is formed it attacks the positive (δ+) carbonyl carbon of (py)(ph)CO | en |
dc.description.abstract | as the carbanion forms the new C-C bond, the π electrons of the carbonyl group of the original ligand are transferred completely to oxygen forming the alkoxide-type ligand LE-. The CuII ions are doubly bridged by the alkoxide oxygen atoms of the two 2.21 LE- ligands. Simplified mechanistic views of the CuII-assisted formation of the transformed ligands are proposed. Dc magnetic susceptibility studies in the 2-300 K range for the representative complexes 3-6 reveal the presence of very strong antiferromagnetic CuII⋯CuII exchange interactions in the dinuclear complexes 3, 5, and 6 and within the dimeric {Cu2(OMe)(NO3){(py)(ph)CO}(LC)}+ subunits of 4. The strong antiferromagnetic coupling is discussed in terms of the large Cu-O-Cu angles (101.0-102.9°) in the dinuclear, planar {Cu2O2} units/subunits of 3-6. © The Royal Society of Chemistry 2016. | en |
dc.source | Dalton Transactions | en |
dc.source.uri | https://www.scopus.com/inward/record.uri?eid=2-s2.0-84953790639&doi=10.1039%2fc5dt03912f&partnerID=40&md5=9e7d58ae2343af87bf0174deec06246f | |
dc.subject | Ketones | en |
dc.subject | Metals | en |
dc.subject | Oxygen | en |
dc.subject | Antiferromagnetism | en |
dc.subject | Magnetic susceptibility | en |
dc.subject | Metal ions | en |
dc.subject | Ligands | en |
dc.subject | Mixtures | en |
dc.subject | Copper compounds | en |
dc.subject | Copper | en |
dc.subject | Coordination reactions | en |
dc.subject | Atoms | en |
dc.subject | Nitrogen oxides | en |
dc.subject | Addition reactions | en |
dc.subject | Antiferromagnetics | en |
dc.subject | Methanol | en |
dc.subject | Antiferromagnetic coupling | en |
dc.subject | Cationic complexes | en |
dc.subject | Condensation reactions | en |
dc.subject | Coordination clusters | en |
dc.subject | DC magnetic susceptibility | en |
dc.subject | Dinuclear complex | en |
dc.subject | Intramolecular nucleophilic attack | en |
dc.subject | Nucleophilic additions | en |
dc.title | Interesting copper(ii)-assisted transformations of 2-acetylpyridine and 2-benzoylpyridine | en |
dc.type | info:eu-repo/semantics/article | |
dc.identifier.doi | 10.1039/c5dt03912f | |
dc.description.volume | 45 | |
dc.description.issue | 3 | |
dc.description.startingpage | 1063 | |
dc.description.endingpage | 1077 | |
dc.author.faculty | 002 Σχολή Θετικών και Εφαρμοσμένων Επιστημών / Faculty of Pure and Applied Sciences | |
dc.author.department | Τμήμα Χημείας / Department of Chemistry | |
dc.type.uhtype | Article | en |
dc.description.notes | <p>Cited By :7</p> | en |
dc.source.abbreviation | Dalton Trans. | en |
dc.contributor.orcid | Tasiopoulos, Anastasios J. [0000-0002-4804-3822] | |
dc.contributor.orcid | Nastopoulos, Vassilios [0000-0003-4190-1342] | |
dc.contributor.orcid | Kitos, Alexandros A. [0000-0002-1431-3206] | |
dc.gnosis.orcid | 0000-0002-4804-3822 | |
dc.gnosis.orcid | 0000-0003-4190-1342 | |
dc.gnosis.orcid | 0000-0002-1431-3206 | |