Universität zu Köln

Ghorbali, Lokmen ORCID: 0009-0009-0899-885X, Stojadinovic, Vladimir Kjartan ORCID: 0009-0006-1736-3213, Klein, Axel ORCID: 0000-0003-0093-9619 and Chebbi, Hammouda ORCID: 0000-0002-0726-7053 (2025). The Impact of Supramolecular Forces on the Magnetic and Optical Properties of Bis(2-amino-6-bromopyridinium) Tetrachloridocuprate (C5H6BrN2)2[CuCl4]. Inorganics, 13 (10). MDPI. ISSN 2304-6740

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Abstract

[Artikel-Nr. 339] The organic/inorganic hybrid compound bis(2-amino-6-bromopyridinium) tetrachloridocuprate(II) (HABPy)2[CuCl4] was synthesized in crystalline form in a 77% yield from aqueous HCl solutions containing Cu(OAc)2 and 2-amino-6-bromopyridine (ABPy). Single-crystal X-ray diffraction analysis revealed that the compound crystallizes in the monoclinic, centrosymmetric space group C2/c. The Cu atom shows a distorted tetrahedral coordination geometry with a τ4 value of 0.69 (τ4 = 1 for a perfect tetrahedron). The structure consists of organic (HABPy)+ cation layers at z = 0 and z = ½, alternating with inorganic [CuCl4]2− dianion layers at z = ¼ and z = ¾. These layers, parallel to the (001) plane, are interconnected by a plethora of supramolecular forces such as N–H···Cl hydrogen bonds, forming a three-dimensional network. Powder X-ray diffraction confirmed the purity of the synthesized bulk material. Fourier-transform infrared (FT-IR) spectroscopy and Raman spectroscopy support the protonation of the pyridine N atom. Hirshfeld surface analysis allowed us to further study the supramolecular forces in the crystal structure. The material shows purely paramagnetic behavior according to S = ½ with an effective magnetic moment µeff of 1.85 µB and a g factor of 2.14, in keeping with magnetically isolated [CuCl4]2− dianions. UV-vis diffuse reflectance spectroscopy of the orange-red material showed a tiny band at 314 nm and an intense band peaking at 622 nm. The optical gap was found to be 2.25 eV. The photoluminescence spectrum shows a partially structured band with maxima at 416 and 436 nm when irradiating at 370 nm, the wavelength of the maximum band found in the excitation spectrum.

Item Type:	Article
Creators:	Creators Email ORCID ORCID Put Code Ghorbali, Lokmen UNSPECIFIED https://orcid.org/0009-0009-0899-885X UNSPECIFIED Stojadinovic, Vladimir Kjartan UNSPECIFIED https://orcid.org/0009-0006-1736-3213 UNSPECIFIED Klein, Axel UNSPECIFIED https://orcid.org/0000-0003-0093-9619 UNSPECIFIED Chebbi, Hammouda UNSPECIFIED https://orcid.org/0000-0002-0726-7053 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-800808
Identification Number:	10.3390/inorganics13100339
Journal or Publication Title:	Inorganics
Volume:	13
Number:	10
Number of Pages:	17
Date:	16 October 2025
Publisher:	MDPI
ISSN:	2304-6740
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Biochemistry
Subjects:	Chemistry and allied sciences Life sciences
Uncontrolled Keywords:	Keywords Language 2-amino-6-bromopyridinium ; tetrachloridocuprate(II) ; isomeric structures ; supramolecular interactions ; optical properties ; magnetic susceptibility English
['eprint_fieldname_oa_funders' not defined]:	Publikationsfonds UzK
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/80080