Universität zu Köln

Butsch, Katharina, Sandleben, Aaron, Dokoohaki, Maryam Heydari, Zolghadr, Amin Reza and Klein, Axel ORCID: 0000-0003-0093-9619 (2019). Pyridine-2,6-Dicarboxylic Acid Esters (pydicR(2)) as O,N,O-Pincer Ligands in Cu-II Complexes. Inorganics, 7 (4). BASEL: MDPI. ISSN 2304-6740

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Abstract

The pyridine-2,6-carboxylic esters pydicR(2) with R = Me or Ph form the unprecedented mononuclear Cu-II complexes [Cu(pydicR(2))Cl-3](-) in one-pot reactions starting from pyridine-2,6-carboxychloride pydicCl(2), Cu-II chloride, and NEt3 in MeOH or PhOH solution under non-aqueous conditions. The triethylammonium salts (HNEt3)[Cu(pydicR(2))Cl-3] were isolated. The methyl derivative could be crystallized to allow a XRD structure determination. Both structures were optimized using DFT calculations in various surroundings ranging from gas phase and the non-coordinating solvent CH2Cl2 to the weakly coordinating acetone and well-coordinating solvents acetonitrile (MeCN) or dimethylformamide (DMF), while detailed calculation showed the charge distribution, dipole moments, and HOMO-LUMO gap energies changing upon solvation. According to these calculations, the ion pairs and the anionic Cu-II complexes were stable, which shows only Cu-Cl bond elongation and weakening of the charge transfer between the anionic complex and the cation as solvents become polar. Synthesis attempts in the presence of water yielded the Cu-II complexes [Cu(pydic)(OH2)(2)](n) and [Cu(OH2)(6)][{Cu(pydic)}(2)(mu-Cl)(2)], which results from pydicCl(2) hydrolysis. Alternatively, the new pydic(IPh)(2) (IPh = 2-iodo-phenyl) ester ligand was synthesized and reacted with anhydrous CuCl2, which yields the new binuclear complex [{Cu(pydic(IPh)(2))Cl}(2)(mu-Cl)(2)]. EPR spectroscopy of the solid compounds reveals typical axial spectra in line with the observed and DFT calculated geometries. Cyclic voltammetry and UV-vis absorption spectroscopy in solution are in line with un-dissociated complex species [Cu(pydicR(2))Cl-3](-).

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Butsch, Katharina UNSPECIFIED UNSPECIFIED UNSPECIFIED Sandleben, Aaron UNSPECIFIED UNSPECIFIED UNSPECIFIED Dokoohaki, Maryam Heydari UNSPECIFIED UNSPECIFIED UNSPECIFIED Zolghadr, Amin Reza UNSPECIFIED UNSPECIFIED UNSPECIFIED Klein, Axel UNSPECIFIED orcid.org/0000-0003-0093-9619 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-151620
DOI:	10.3390/inorganics7040053
Journal or Publication Title:	Inorganics
Volume:	7
Number:	4
Date:	2019
Publisher:	MDPI
Place of Publication:	BASEL
ISSN:	2304-6740
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Inorganic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language DINUCLEAR COPPER(II) COMPLEX; DIMETHYL PYRIDINE-2,6-DICARBOXYLATE; MOLECULAR-DYNAMICS; HELICAL COMPLEXES; CRYSTAL-STRUCTURE; HIGHLY EFFICIENT; X-RAY; COORDINATION; CONSEQUENCES; CADMIUM(II) Multiple languages Chemistry, Inorganic & Nuclear Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15162