First Structural and Magnetic Studies of Ni Clusters Containing 2,6-Diacetylpyridine-dioxime as a Ligand

Abstract

In the present work, coordination possibilities of the system dapdoH(2)/Ni(2+), being dapdoH(2) = 2,6-diacetylpyridine dioxime, have been explored, offering as a result a number of unprecedented clusters with a variety of topologies and magnetic behaviors. Depending on the precursors and reaction conditions, several compounds named [Ni(2)(dapdo)(2)] (1), [Ni(3)(OH)(BzO)(3)(dapdo)(dapdoH(2))(H(2)O)] x1.25 H(2)O (2), [Ni(3)(AcO)(4)(dapdoH)(2)(H(2)O)(2)] x H(2)O (3), and [Ni(4)(AcO)(3)(dapdo)(dapdoH)(2)(H(2)O)(3)] x (AcO) x 3 H(2)O (4) were achieved and structurally well-characterized. Dc magnetic measurements were carried out in the 2-300 K range revealing antiferromagnetic interactions for (2-4) compounds and diamagnetic response for the square planar coordinated complex (1).

Multireversible Redox Processes in a Self‐Assembled Nickel Pentanuclear Bis(Triple‐stranded Helicate): Structural and Spectroscopic Characterizations in the NiII5 and NiINiII4 Redox States

“…Regarding the trinuclear central core, the average of the Ni eq ‐N,O bond distances in 1 3+ , in the range 2.02–2.03 Å, are likewise fully consistent with three high‐spin Ni(II) (Table 1). [64] In addition, the Ni‐ μ ‐OH bond distances, in the range 2.008‐2.031 Å, are similar to those found in trinuclear nickel complexes featuring a Ni II 3 ( μ 3 ‐OH) core [65–68] and longer than those of trinuclear compounds with a Ni II 3 ( μ 3 ‐O) core (in the range 1.785‐1.803 Å) [69–70] fully consistent with the protonation of the central oxygen.…”

“…All these minor structural changes between the Ni II 5 ( 1 3+ ) and Ni I Ni II 4 ( 1 2+ ) redox states are similar to those previously observed when comparing the X‐ray crystallographic structures of the analogous [{Co II ( μ ‐bpp) 3 } 2 Co II 3 ( μ 3 ‐OH)] 2+ and [{Co II ( μ ‐bpp) 3 } 2 Co I Co II 2 ( μ 3 ‐OH)] 2+ complexes, in which, the reduction of the Co(II) ion to Co(I) takes also place in the core. Few examples of triangular trinuclear nickel complexes featuring a Ni II 3 ( μ 3 ‐OH), [65–68] and a Ni II 3 ( μ 3 ‐O) [69–70] core have been reported and only one example of a mixed‐valence trinuclear Ni II 2 Ni III ( μ 3 ‐OH) center as unit in a porous framework [71] . The nickel ions in these complexes are either tetra‐ or hexa‐coordinated while unusual five‐coordinated metal ions are found in the Ni 3 II ( μ 3 ‐OH) core in 1 3+ and 1 2+ .…”

Dinuclear, tetranuclear and polymeric complexes in copper(ii) perchlorate/pyridine-2,6-diamidoxime chemistry: synthetic, structural and magnetic studies

“…In another step, we studied complexes with anionic ligands in which R contains a donor site, i.e., complexes of pyaoxH -/pyaox 2-32 and (py)pko -29b, 33 In a third step, we recently initiated a study of the metal cluster and polymer chemistry of 2,6-diacetylpyridine dioxime (dapdoH 2 ; Scheme 1) and reported Mn II 3 , (Mn II 3 ) n , Mn II 2 Mn III 4 , Mn II 6 Mn III 2 , Ni II 2 , Ni II 3 and Ni II 4 complexes. [34][35][36] Our studies in metal/dapdoH 2 chemistry joined previous literature reports 24,37 on the employment of dapdoHand dapdo 2for the preparation of Mn II 2 Mn III 4 , 24a,b Mn II 2 Mn III 6 , 24a Gd III 2 Mn IV , 24c Cu II 2 Cr III 2 , 37a and Fe II Fe III 2 37b clusters, as well as dinuclear Cu II 2 complexes. 37c A natural extension of such studies is the investigation of 2,6-pyridyl dioximes in which the non-donor Me groups are replaced by potentially donor groups.…”

Manganese clusters derived from a 2,6-diacetylpyridine dioximato ligand: structure and magnetic study

“…25 The first Ni 2+ polynuclear derivatives with a variety of nuclearities and topologies have been recently reported by our group highlighting that dapdo 2is prone to stabilize the square planar environment around the nickel cations. 26 Following our work in the field of metal-oximato clusters we would like to introduce in this work the synthesis of two new hexanuclear mixed-valence systems with the formula…”