Structural, magnetic, high-frequency and high-field EPR investigation of double-stranded heterometallic [{Ni(en)2}2(µ-NCS)4Cd(NCS)2]n·nCH3CN polymer self-assembled from cadmium oxide, nickel thiocyanate and ethylenediamine

Abstract

A novel heterometallic 1D coordination polymer [{Ni(en)2}2(micro-NCS)4Cd(NCS)2](n) x nCH3CN (en = ethylenediamine) has been prepared using the self-assembly process in a one-pot reaction of cadmium oxide, nickel and ammonium thiocyanates with an acetonitrile solution of ethylenediamine. The complex consists of an uncommon cis-Cd(SCN)4(NCS)2(4-) fragment and a rare combination of cis-Ni(en)2(2+) and trans-Ni(en)2(2+) building blocks linked by micro(1,3)-NCS bridges into a double-stranded zigzag chain structure. Each chain is comprised of [Ni2Cd2(micro-NCS-N,S)4)] macrocycles with chair-like and rectangular-like shapes arrayed alternately. The shortest intrachain CdCd separations are 9.535(1) and 10.868(2) A, while the nearest NiNi distances are 5.418(1) and 6.612(2) A. A network of weak N-HS hydrogen bonds, involving the terminal NCS ligands and NH2-groups of en, links the infinite chains and results in the formation of an extended supramolecular three-dimensional framework. Variable-temperature (1.8-300 K) magnetic susceptibilities show a slight change of the micro(B) value at low temperature, indicative of weak antiferromagnetic interactions (J = 1.55 cm-1) between magnetic canters. High-field, high-frequency (100-400 GHz) EPR spectra were simulated using S = 1 ground state for separate Ni2+ ions with the spin Hamiltonian parameters g = 2.165, D = 0.45 cm-1 and E = 0.03 cm(-1). According to DFT calculations, the D and E parameters are -0.35 cm(-1) and 0.049 cm-1 for the cis arrangement of Ni2+ and 0.58 cm(-1) and 0.012 cm(-1) for trans.

Syntheses, structures and properties of a new compound of the type [Zn(4,4′-dmo-2,2′-bpy)2(CH3COO)]2[Zn(SCN)4]·H2O with zinc in two cationic and one anionic complexes

“…Simultaneous presence of two different metal centers can potentially give rise to interesting physico-chemical properties and lead to attractive novel topologies and intriguing frameworks. However, despite the various coordination modes of the SCN -group to the metalions, it is not widely used in the design and synthesis of inorganic compounds and the heterometallic thiocyanato bridged species are comparatively less numerous [6].…”

One-dimensional ladder like and two-dimensional polymorphs of heterometallic thiocyanate bridged copper(II) and mercury(II) coordination polymer: Syntheses, structural, vibration, luminescence and EPR studies

“…This interest is based on not only the architectonical diversity and extreme versatility of their bridging modes, but also on their encouraging properties and exceptional potential applications. In this context, the thiocyanate ligand with the ambidentate character of its versatile bridging coordination modes, is expected to afford a number of homo-and heterometallic discrete, one-, two and three-dimensional structural assemblies with specific structural features and optical and magnetic properties [35][36][37][38][39][40][41][42][43][44]. Simultaneous presence of two different metals might give rise to interesting physicochemical properties and lead to attractive novel topologies and intriguing frameworks.…”

Dicarboxylate assisted synthesis of the monoclinic heterometallic tetrathiocyanato bridged copper(II) and mercury(II) coordination polymer {Cu[Hg(SCN)4]} : Synthesis, structural, vibration, luminescence, EPR studies and DFT calculations

“…This interest is based not only on the high versatility of their binding modes which are end-on-Z 1 (N), end-on-Z 1 (X), bridging-Z 1 (N)-Z 1 (X), bridging-m-Z 1 (N), bridging-m-Z 1 (X) and combinations of these and allow a rich architectonical diversity in corresponding structures, but also on their exceptional potential applications. The thiocyanate ligand with its marked ambidentate character and all the versatile coordination modes described above is expected to afford a number of homo-and heterometallic discrete one-, two-and three-dimensional structural assemblies with specific structural features and optical and magnetic properties [31][32][33][34]. Simultaneous presence of two different metal centers can potentially give rise to interesting physico-chemical properties and lead to attractive novel topologies and intriguing frameworks.…”

“…Simultaneous presence of two different metal centers can potentially give rise to interesting physico-chemical properties and lead to attractive novel topologies and intriguing frameworks. However, despite the various coordination modes of the SCN À group to the metal ions, it is not widely used in the design and synthesis of inorganic compounds and the heterometallic thiocyanato bridged species are comparatively less numerous [34].…”