A Unique Trinuclear, Triangular Ni(II) Complex Composed of Two tri-Anionic bis-Oxamates and Capping Nitroxyl Radicals

A Unique Trinuclear, Triangular Ni(II) Complex Composed of Two tri-Anionic bis-Oxamates and Capping Nitroxyl Radicals Full article

Journal

Inorganics
ISSN: 2304-6740

Output data

Year: 2025, Volume: 13, Number: 7, Article number : 214, Pages count : 14 DOI: 10.3390/inorganics13070214

Tags

nickel(II); trinuclear complex; imino nitroxide; bis-oxamate ligand; magnetic properties

Authors

Morozov Vitaly A. ¹ , Samsonenko Denis G. ² , Vostrikova Kira E. ²

Affiliations

1	International Tomography Center SB RAS, Institutskaya Str. 3a, 630090 Novosibirsk, Russia
2	Nikolaev Institute of Inorganic Chemistry SB RAS, 3 Lavrentiev Avenue, 630090 Novosibirsk, Russia

Phenylene-based bis-oxamate polydentate ligands offer a unique opportunity for creating a large variety of coordination compounds, in which paramagnetic metal ions are strongly magnetically coupled. The employment of imino nitroxyl (IN) radicals as supplementary ligands confers numerous benefits, including the strong ferromagnetic interaction between Ni and IN. Furthermore, the chelating IN can act as a capping ligand, thereby impeding the formation of coordination polymers. In this study, we present the molecular and crystal structure and experimental and theoretical magnetic behavior of an exceptional neutral trinuclear complex [Ni(L3−)2(IN)3]∙5CH3OH (1) (L is N,N′-1,3-phenylenebis-oxamic acid; IN is [4,4,5,5-tetramethyl-2-(6-methylpyridin-2-yl)-4,5-dihydro-1H-imidazol-1-yl]oxidanyl radical) with a cyclic triangular arrangement. Moreover, in this compound three Ni2+ ions are linked by the two bis-oxamate ligands playing a rare tritopic function due to an unprecedented triple deprotonation of the related meta-phenylene-bis(oxamic acid). The main evidence of such a deprotonation of the ligand is the neutrality of the cluster, since there are no anions or cations compensating for its charge in the crystals of the compound. Despite the presence of six possible magnetic couplings in the trinuclear cluster 1, its behavior was reproduced with a high degree of accuracy using a three-J model and ZFS, under the assumption that the three different Ni-IN interactions are equal to each other, whereas only two equivalent-in-value Ni-Ni interactions were taken into account, with the third one being equated to zero. Our study indicates the presence of two opposite-in-nature types of magnetic interactions within the triangular core. DFT and CASSCF/NEVPT2 calculations were completed to support the experimental magnetic data simulation.

Morozov V.A. , Samsonenko D.G. , Vostrikova K.E.
A Unique Trinuclear, Triangular Ni(II) Complex Composed of Two tri-Anionic bis-Oxamates and Capping Nitroxyl Radicals
Inorganics. 2025. V.13. N7. 214 :1-14. DOI: 10.3390/inorganics13070214

Submitted:	May 24, 2025
Accepted:	Jun 23, 2025
Published print:	Jun 25, 2025
Published online:	Jun 25, 2025

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