Quasi-2D Heisenberg Antiferromagnets [CuX(pyz) 2 ](BF 4 ) with X = Cl and Br

Kubus, Mariusz; Lanza, Arianna; Scatena, Rebecca; Dos Santos, Leonardo H. R.; Wehinger, Björn; Casati, Nicola; Fiolka, Christoph; Keller, Lukas; Macchi, Piero; Rüegg, Christian; Krämer, Karl (2018). Quasi-2D Heisenberg Antiferromagnets [CuX(pyz) 2 ](BF 4 ) with X = Cl and Br. Inorganic chemistry, 57(9), pp. 4934-4943. American Chemical Society 10.1021/acs.inorgchem.7b03150

[img] Text
acs.inorgchem.7b03150.pdf - Published Version
Restricted to registered users only
Available under License Publisher holds Copyright.

Download (1MB) | Request a copy

Two Cu2+ coordination polymers [CuCl(pyz)2](BF4) 1 and [CuBr(pyz)2](BF4) 2 (pyz = pyrazine) were synthesized in the family of quasi two-dimensional (2D) [Cu(pyz)2]2+ magnetic networks. The layer connectivity by monatomic halide ligands results in significantly shorter interlayer distances. Structures were determined by single-crystal X-ray diffraction. Temperature-dependent X-ray diffraction of 1 revealed rigid [Cu(pyz)2]2+ layers that do not expand between 5 K and room temperature, whereas the expansion along the c-axis amounts to 2%. The magnetic susceptibility of 1 and 2 shows a broad maximum at ∼8 K, indicating antiferromagnetic interactions within the [Cu(pyz)2]2+ layers. 2D Heisenberg model fits result in J∥ = 9.4(1) K for 1 and 8.9(1) K for 2. The interlayer coupling is much weaker with |J⊥| = 0.31(6) K for 1 and 0.52(9) K for 2. The electron density, experimentally determined and calculated by density functional theory, confirms the location of the singly occupied orbital (the magnetic orbital) in the tetragonal plane. The analysis of the spin density reveals a mainly σ-type exchange through pyrazine. Kinks in the magnetic susceptibility indicate the onset of long-range three-dimensional magnetic order below 4 K. The magnetic structures were determined by neutron diffraction. Magnetic Bragg peaks occur below TN = 3.9(1) K for 1 and 3.8(1) K for 2. The magnetic unit cell is doubled along the c-axis (k = 0, 0, 0.5). The ordered magnetic moments are located in the tetragonal plane and amount to 0.76(8) μB/Cu2+ for 1 and 0.6(1) μB/Cu2+ for 2 at 1.5 K. The moments are coupled antiferromagnetically both in the ab plane and along the c-axis. The Cu2+ g-tensor was determined from electron spin resonance spectra as gx = 2.060(1), gz = 2.275(1) for 1 and gx = 2.057(1), gz = 2.272(1) for 2 at room temperature.

Item Type:

Journal Article (Original Article)


08 Faculty of Science > Department of Chemistry, Biochemistry and Pharmaceutical Sciences (DCBP)

UniBE Contributor:

Macchi, Piero, Krämer, Karl


500 Science > 570 Life sciences; biology
500 Science > 540 Chemistry




American Chemical Society


[4] Swiss National Science Foundation




Piero Macchi

Date Deposited:

29 May 2018 15:10

Last Modified:

05 Dec 2022 15:14

Publisher DOI:






Actions (login required)

Edit item Edit item
Provide Feedback