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

[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 Eg ≈ 13.4 cm−1 is comparable with those found in archetypal Haldane gap systems.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]. NF thanks National Scholarship Programme of the Slovak Republic for financial support of her research stay at the University of Zaragoza (Spain).Peer Reviewe