[Ni(bpy)(ox)]: a candidate in the class of Haldane gap systems (bpy = 2,2ʹ-bipyridine, ox = oxalate)

Abstract

[Ni(bpy)(ox)] (bpy = 2,2ʹ-bipyridine; ox = oxalate) was solvothermally prepared in the microcrystalline form and identified by chemical analyses and IR spectroscopy. X-ray powder diffractometry indicates its isostructural character with analogous complexes [M(bpy)(ox)], and thus, its chain-like crystal structure formed of {Ni(bpy)} building units linked by bridging oxalate anions coordinated in a bis(chelate) fashion. The temperature dependence of the magnetic susceptibility and the field dependence of the magnetization reveal that the studied compound belongs to the class of systems with a Haldane gap. The estimated magnitude of the gap E_g ≈ 13.4 cm⁻¹ is comparable with those found in archetypal Haldane gap systems.

Graphical abstract

Keywords:

• Nickel
• Oxalate
• 2,2ʹ-Bipyridine
• Chain structure
• Rietveld method
• Haldane gap
• Excitation spectrum
• Quantum spin chain

Acknowledgment

NF thanks National Scholarship Programme of the Slovak Republic for financial support of her research stay at the University of Zaragoza (Spain).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Slovak grant agencies VEGA [grant number 1/0075/13]; APVV [grant number APVV-0132-11]; VVGS [grant number VVGS-2014-164]; Ministry of Science and Innovation (Spain) [grant number MAT2011–27233-C02–01]- European Union Regional Development Fund; Diputación General de Aragón [grant number E-16]; the European Union Regional Development Fund (Slovakia) [ITMS: 26220120047].