Double azido-bridged and mixed-bridged binuclear copper(II) and nickel(II) compounds with N,N,O-donor Schiff bases: Synthesis, structure, magnetic and DFT study

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

“…However, although a large number of μ 1,1 ‐azido‐bridged dinickel(II) systems are known, unlike theoretical prediction, the experimental data do not show clear relationship with Ni–N–Ni angles as a small variation of Ni−N−Ni angles in the narrow range ca . 98°–103.9°, show a large variation of the J values from 1.91 to 43.9 cm −1 [13–20,31−33,35−46] . This is confirmed by the fact that the present bridging angel of 101.99(1)° is very close to the value of 101.0° in [Ni 2 (L 1 )2( μ 1,1 ‐N 3 )2(N 3 ) 2 ] (L 1 =a tridentate quinoline‐based ligand) [33] and 101.79° (average value) in [Ni 2 (L 2 ) 2 (N 3 ) 2 ( μ 1,1 ‐N 3 ) 2 ]⋅CH 3 OH (L 2 = N , N ‐dimethyl‐ N ′‐(pyrid‐2‐ylmethyl)‐ethylenediamine), [63] but show quite different J values of 6.1 and 1.91 cm −1 , respectively.…”

“…Our data provide us information that chloride (J = 6.84(10) cm À 1 ) is better magnetic coupler than cyanate ion (J = 5.31(4) cm À 1 ). If we look at the reported results, it is seen that J values (considering Ĥ = À 2JŜ 1 ⋅Ŝ 2 ) vary from 1.91 to 43.9 cm À 1 in doubly μ 1,1 -azido-bridged dinickel(II) complexes, [13][14][15][16][17][18][19][20][31][32][33][35][36][37][38][39][40][41][42][43][44][45][46] while the ranges are 1.7 to 6.85 cm À 1 [19,21,24] and 3.48 to 14.59 cm À 1 [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] for doubly μ 1,1cyanato-bridged and doubly μ-chloro-bridged analogues, respectively, and the trend of their average values is exactly replicated in the present study, that help us to conclude that μ 1,1 -azido is superior magnetic exchanger among them, followed by μ-chloro and μ 1,1 -cyanato.…”

Magneto-structural studies on a number of doubly end-on cyanate and azide bridged dinuclear nickel(ii) complexes with {N3O} donor Schiff base ligands

“…However, unlike theoretical prediction, a large number of magnetically characterized μ 1,1 -azido-bridged dinuclear Ni II systems do not display a clear relationship of J values with the Ni–N–Ni bridging angles as a small variation of the Ni–N–Ni angles in a narrow range of 98°–103.9° display a wide range of J values from 1.91 to 43.9 cm −1 . 31–51 This can be further confirmed by the fact that the present bridging angles of 101.00(8)° and 101.99(8) ° for 1 and 101.48(5)° for 3 are comparable to the value of 101.0° in [Ni 2 (L 7 )2( μ 1,1 -N 3 )2(N 3 ) 2 ] (L 7 = a tridentate quinoline-based ligand) 40 and 101.79° (average angle) in [Ni 2 (L 8 ) 2 (N 3 ) 2 ( μ 1,1 -N 3 ) 2 ]·CH 3 OH (L 8 = N , N -dimethyl- N ′-(pyrid-2-ylmethyl)-ethylenediamine), 54 yet they display significantly different J values of 6.1 and 1.91 cm −1 , respectively. In contrast, the magnetic coupling constants of the present systems are nicely matched with other reported compound [Ni(pepci)( μ 1,1 -N 3 ) 2 ] 2 (where pepci = N ′-(2-pyridin-2-ylethyl)pyridine-2-carbaldimine) 47 that displayed very similar bridging angle of 101.6° with J value of 36.3 cm −1 .…”

“…The Ni–N bond lengths of imine, secondary amine and tertiary amine of the Schiff base ligands span in the range 2.046(2) to 2.239(2) Å in 1–8 , which are comparable to those found in closely related Ni II complexes reported in the literature (Table 2). 17–23,31–51 The central {NiN 2 Ni} core in 1 and 3 is planar with the metal–metal separation and the Ni–N–Ni bridging angles are 3.355(1) and 3.374(1) Å, and 101.00(8)°–101.99(8)°, respectively. Similarly, the metal–metal separations (3.327(1)–3.235(1) Å) in the central {NiN 2 Ni} core structures in 2–8 are very similar as that found in 1 and 3 , but the Ni–N–Ni bridging angles in the range 96.79(9)–99.87(8)° are slightly lower than that found in 1 and 3 .…”

Two dinuclear copper (II) and nickel (II) complexes based on 4‐(diethylamino)salicylaldehyde: X‐ray structures, spectroscopic, electrochemical, antibacterial, Hirshfeld surfaces analyses, and time‐dependent density functional theory calculations

“…Two central metal ions diverged from every one basal plane by 0.018 and 0.013 Å, which it means M (II) and four donor atoms are approximately coplanar. [ 34,35 ] The M (II) centers were viewed as a slightly distorted octahedral with N 2 O 4 donor environment. The distance of the apical N2 and O2 to the basal plane being 1.9323(19) and 1.9534(16) Å for 1 , whereas for 2 , the values of these distance were 1.986 and 2.056 Å, respectively.…”