Metal complexes formed by metal-assisted solvolysis of di-pyridylketone azine: structures and magnetic properties

Abstract

A series of metal complexes were achieved from the metal-assisted solvolysis reaction of di-pyridylketone azine (dpka). The tetranuclear nickel cluster , [Ni(2)[dpk(O)(OH)][dpk(O)(OCH(3))](N(3))(2)](2), is centrosymmetric with a central core described as an edge-shared triangle core. Neighboring Ni(II) ions are alternately bridged by (micro(2)-N(3), micro(3)-O) and (micro(2)-O, micro(3)-O) double bridges. Complex , [Cu(4)[dpk(O)(OCH(3))](4)(N(3))(2)](CuCl(2))(2) contains a tetranuclear cluster and two identical [CuCl(2)]M(-) anions. The tetranuclear structure has two crystallographically imposed twofold axes, in which the four copper ions are arranged to be rhombic shape. The neighboring copper(ii) ions along the lateral are bridged by single micro(2)-O from the ligand dpk(O)(OCH(3)) and the short diagonal copper ions are bridged by two symmetric end-on azides. In dinuclear Cu(ii) complex [Cu(2)[dpka(OCH(2)CH(3))]Cl(2)](ClO(4)) (3), the metal centers are coordinated in a planar configuration and bridged by a -N-N- bridge. It is also observed that the Cl atom coordinated to one Cu(II) center is also weakly coordinated to another inversion related Cu(II) to generate a centrosymmetric dimer. The metal centers in one-dimensional polymeric Cu(ii) complex [Cu(2)[dpka(OCH(3))](N(3))(2)(ClO(4))](n) (4), however, are bridged by a -N-N- bridge and an end-to-end azide bridge, alternately. Magnetic susceptibility measurements indicate that shows ferromagnetic interaction within the tetranuclear cluster, and that displays moderately strong antiferromagnetic interaction (J = -56.7 cm(-1)) for the bis(micro-N(3)) bridge. For compound , it shows strong antiferromagnetic coupling (J = -286 cm(-1)) between the intradinuclear Cu(II) ions mediated by the single N-N bridge and negligible magnetic interactions between the adjacent dinuclear Cu(II) ions mediated by the single end-to-end azide bridge. The mechanism of the metal-assisted solvolysis reaction was also discussed.

Magnetic and Electrochemical Properties of a Heterobridged μ‐Phenoxido–μ1,1‐Azide Dinickel(II) Compound: A Unique Example Demonstrating the Bridge Distance Dependency of Exchange Integral

“…As already mentioned, heterobridged compounds of 3d metal ions, other than copper(II), are limited. Regarding μ‐phenoxido/alkoxido/hydroxido–μ‐azide nickel(II) systems, few polymetallic μ‐alkoxido–μ‐azide Ni II 10 , Ni II 14 andNi II 12 Na I 2 clusters,10 one μ‐alkoxido–μ‐azide hexanickel(II) compound,11a a few μ‐alkoxido–μ‐azide tetranickel(II) systems,11b–11e three μ‐phenoxido–μ‐azide dinickel(II) compounds8 and one hexanickel(II) compound11f having both μ‐alkoxido–μ‐azide and μ‐carbonato–μ‐azide bridging moieties are known. Although magnetic measurements of the Ni II 10 , Ni II 14 and Ni II 12 Na I 2 clusters have been carried out and high‐spin ground states like S T = 10 or 6 have been observed, it was not possible to determine the magnitude of exchange integrals.…”

From Bowls to Capsules: Assembly of Hexanuclear NiII Rings Tailored by Alkali Cations

“…The coordination sphereo fN i(1) and symmetry relatedc ation is fulfilledw itho ne terminala zido ligand. Te tranuclear Ni II clusters derived from dipyridylketone are well known andc omplex 7 shows the same core and connectivity as similarr eported complexes [12][13][14][15][16] and, thus, no further description is needed. The crystallographic parameters and bond parameters are supplied in Tables S2 and S3 in the Supporting Information.…”

“…To p: coupling scheme for complexes 1-4 and 6.Bottom: coupling scheme for complex 7. ology and magnetic response fully agree with the well-studied similar complexes derived from Ni II /dpk/N 3 À reported in the literature. [12][13][14][15][16]…”

“…[10] Dipyridylketone (dpk) is an extensively studied reagent, which in the presenceo fm etal cation undergoes an addition to its carbonyl group of water,m ethanol, or acetonitrile, leading to av ariety of ligands:p y 2 CO(OH) À ,p y 2 C(MeO)O À ,a nd py 2 C(CH 2 CN)O À ,r espectively. [11] The system dpk/azide/Ni II has yieldeds eries of clusters [12][13][14][15][16][17][18][19][20] with nuclearities rangingf rom Ni 4 to Ni 9 .I nterestingly,t he presence of the carbonato templating anion is prone to produce hexanuclear metallamacrocycles. [21,22] One of these systems, reported by To ng et al, [22] is an anionic ring with the formula [Ni 6 (m 6 -CO 3 )(N 3 ) 6 (OAc) 3 (py 2 C(CH 2 CN)(O)) 3 ] 2À ,w hich was ablet ol ink potassiumc ations in a{ Ni 12 K 2 }c luster.R emarkably,t his metallacycle was selectively obtained in the presence of potassium cations and without this cation the conventional defective cubane tetranuclearcomplex was stabilized.…”

Σε Αναζήτηση Μονομοριακών Μαγνητών Και Μαγνητικών Ψυκτών

“…Στο Σχήμα 83 διακρίνεται η δομή ενός τετραπυρηνικού συμπλόκου του Cu(II) που περιέχει το μονοανιοντικό υποκαταστάτη dpkaz(OCH 2 CH 3 ) -. Το κατιόν μπορεί να θεωρηθεί ότι αποτελείται από δύο κεντροσυμμετρικά διμερή [110].…”