Study of zero-field splitting in Ni(II) complexes with near octahedral geometry

• Published in: Inorganica Chimica Acta Vol. 491; pp. 138 - 146
• Main Authors: Lomjanský, Dominik, Rajnák, Cyril, Titiš, Ján, Moncoľ, Ján, Boča, Roman
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.06.2019; Elsevier Science Ltd
• Subjects: Magnetic anisotropy; Magnetic susceptibility; Magnetostructural D-correlations; Methane; Ni(II) complexes; Splitting; X-ray structure; Zero-field splitting; Magnetostructural D-correlations; X-ray structure; Ni(II) complexes; Zero-field splitting; Magnetic susceptibility
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2019.04.005

[Display omitted] •Four new Ni(II) complexes prepared and characterized.•Structure description of two pseudooctahedral and two octahedral/tetrahedral complexes.•Magnetic properties of all complexes determined.•Magnetic anisotropy correlated with structural distortion of chromophore. Four novel Ni(II) complexes, [Ni(dppmO,O)2(NCS)2] 1, [Ni(dppmO,O)3][NiCl4] 2, [Ni(dmbpy)(H2O)2Br2] 3 and [Ni(dppmO,O)3][NiCl4]·[Ni(dppm)Cl2] 4 (dppm = bis(diphenylphosphino)methane, dppmO,O = bis(diphenylphosphanoxido)methane, dmbpy = 4,4′-dimethyl-2,2′-bipyridine), have been synthesized and structurally and magnetically characterized. Complexes 1 and 3 are routinely pseudooctahedral, while 2 and 4 are unique due to the existence of hexa- or tetracoordination in two/three independent Ni(II) atoms. For hexacoordinated systems the magnetic data confirm small magnetic anisotropy expressed through the axial zero-field splitting parameter D/hc = −4.5 to +4.4 cm−1. For [NiCl4]2− tetrahedral units (in complexes 2 and 4) the magnetic anisotropy is substantially larger. Experimental findings have been confirmed by ab initio calculations and forwarded to magnetostructural D-correlations.