The structure and magnetism of mono- and di-nuclear Ni(ii) complexes derived from {N₃O}-donor Schiff base ligands

Abstract

Some mononuclear and dinuclear Ni(ii) complexes with tetradentate Schiff base ligands exhibit zero-field splitting and ferromagnetic coupling, respectively.

Magneto‐structural Studies in Double Chloro‐ and Pseudohalo‐bridged Isomorphic Dinickel(II) Complexes

“…The magnetic and crystallographic data of these five complexes are presented in Table 2, which shows that J values span in a narrow range 1.7 to 6.85 cm À 1 . [19,21,24] The sign and magnitude of J value of 5.31(4) cm À 1 in 4 is again reasonable for such complexes. Interestingly, a general trend can be found in which J value increases with increase in bridging angles, similar to theoretical prediction that has been done for azide analogues.…”

“…Unlike 1, all the nitrogen atoms of the (Table 1), which are comparable to analogous complexes reported in the literature. [21] The centre of symmetry enforces the central Ni(μ-Cl) 2 Ni (in 2) and Ni(μ-N) 2 Ni (in 3 and 4) core structures to be perfectly planer. The bridging angles are 92.27(2), 98.47(2) and 101.99(1)°with metal-metal separations of 3.587(1), 3.274(1) and 3.338(1) Å for 2-4, respectively, which are comparable to those reported earlier.…”

“…[13][14][15][16][17][18][19][20][21] Cyanate ion transmits magnetic interaction between the metal centres almost in similar way as that azide ion does but weakly and a scarcity of reports of such Ni(II) compounds is available in the literature to establish a sophisticated magneto-structural correlation for cyanatobridged Ni(II) systems. [19,21,24] When Ni(II) is five-coordinate, the magnetic coupling observed between the metal ions is usually dominantly AF in nature, while in octahedral or pseudo-octahedral, the coupling is found generally ferromagnetic through chloro-bridge. [25,26] Developing magneto-structural correlations by only experimental means is a very challenging task because that requires structurally similar or identical complexes with all but one governing parameter being identical.…”

“…In contrast, the presence of two hetero‐bridging atoms with polarizable π systems in other pseudohalides, namely cyanate, which can coordinate the metal ions through either of the heteroatoms, or both, are less versatile than the azide ion. Therefore, in contrast to the vast coordination chemistry of azido‐bridged systems, [13–20] both structurally and magnetically interesting compounds with other pseudohalides are limited [21] . It is well known that halides and pseudohalides show great resemblances in several chemical and physical properties, but such similarity in coordination chemistry is quite limited, which is due to lack of coordinative versatility of one‐atom halide ion compared to polyatomic pseudohalides.…”

Magnetic excitations in molecular magnets with complex bridges: the tetrahedral molecule Ni4Mo12

“…The physical properties, such as energy spectra, susceptibility, etc., of magnetic clusters at the nanoscale depend on their size, shape and the presence of different bondings among the constituent chemical elements and thus the distribution of ligands between the magnetic ions (for more details see [1][2][3][4] and references therein). Some prominent examples are Mn based magnetic compounds [5][6][7][8][9][10][11] and spin clusters with Ni magnetic ions [12][13][14][15] .…”