Formation of a dinuclear and a trinuclear Ni(II) complex on slight variation of experimental conditions: Structural analysis and magnetic properties. (10th January 2017) - Biswas, Apurba
Graphical abstract: A diphenoxido bridged antiferromagnetically coupled dinuclear Ni(II) complex [Ni2 L2 (NO2 )2 ] (1 ) and a μ2 and μ3 -phenoxido, μ3 -hydroxido, and μ2 -nitrito (1κ O :2κ N ) bridged ferromagnetically coupled trinuclear Ni(II) complex [Ni3 L3 (OH)(NO2 )]·ClO4 (2 ), have been synthesized using a tridentate reduced Schiff base ligand and varying the reaction conditions. Abstract: A diphenoxido bridged dinuclear Ni(II) complex [Ni2 L2 (NO2 )2 ] (1 ) and a μ2 and μ3 -phenoxido, μ3 -hydroxido, and μ2 -nitrito (1κ O :2κ N ) bridged trinuclear Ni(II) complex [Ni3 L3 (OH)(NO2 )]·ClO4 (2 ), have been synthesized using a tridentate reduced Schiff base ligand HL (HL = 2-[(2-dimethylamino-ethylamino)-methyl]-phenol). Both complexes were characterized by X-ray structure determination and variable-temperature magnetic susceptibility measurements. In both complexes the nickel atoms are six-coordinated with a distorted octahedral environment. The interesting feature of the trimeric complex2 is that the three mononuclear units are assembled around a μ3 -hydroxido ion in such a way that the three phenoxido groups and one nitrito group form a cyclic bridge that markedly modify the magnetic properties. Complex1 presents a moderate antiferromagnetic Ni–Ni coupling ( J = −39 cm −1 ) through the phenoxido bridges with a wide Ni–O–Ni bond angle of 101.77(6)° whereas the lower Ni–O–Ni bond angles, in the range 86.66(6)–96.07(7)°, lead to a moderate ferromagnetic coupling ( J = +18.2 cm −1 ) in the trimeric complex2 with a weak antiferromagnetic contribution ( J ′ = −0.51 cm −1 ) via the 1κ O :2κ N nitrito bridge.