Synthesis and characterization of a new layered organic–inorganic hybrid nickel(II) 1,4:5,8-naphthalenediimide bis-phosphonate, exhibiting canted antiferromagnetism, with Tc∼21 K

A new Ni(II) layered hybrid organic-inorganic compound of formula Ni2[(NDI-BP)(H2O)2]·2H2O has been prepared in very mild conditions from N,N′-bis(2-phosphonoethyl)napthalene-1,4:5,8-tetracarboximide (NDI-BP ligand) and NiCl2. The X-ray powder structure characterization of the title compound suggests a pillared layered organic-inorganic hybrid structure. The distance between the organic and inorganic layers has been found to be 17.8 Å. The inorganic layers consist of corner sharing [NiO5(H2O)] octahedra and they are pillared by the diphosphonate groups. DC and AC magnetic measurements as a function of temperature and field indicate the presence of 2D antiferromagnetic exchange interactions between the nearest-neighbor Ni(II) ions below 100 K. A long-range magnetic ordering at Tc∼21 K has been established and is attributed to the presence of spin canting. AC magnetic measurements as a function of temperature at different frequencies confirm the occurrence of the magnetic ordering temperature at T=21 K and the presence of a slight structural disorder in the title compound.

Graphical abstractA new layered hybrid organic–inorganic Ni(II) N,N′-bis(2-phosphonoethyl)-naphthalene 1,4:5,8 tetracarboxydiimide complex has been synthesized and characterized. Magnetic measurements as a function of temperature and at different fields show that the compound is magnetically ordered below Tc∼21 K.Figure optionsDownload full-size imageDownload as PowerPoint slide