Unusual Magnetic Metal–Cyanide Cubes of Re^II with Alternating Octahedral and Tetrahedral Corners

Abstract

Two cyanide‐bridged molecular cubes of general formula [{MCl}4{ReII(triphos)(CN)3}4], M=Fe, Co (depicted), triphos=1,1,1‐tris(diphenylphosphanylmethyl)ethane, and their magnetic properties are reported. The cubes are prepared in good yields from the reaction of the ReII complex [Et4N][ReII(triphos)(CN)3] with the appropriate divalent metal halide and consist of octahedral ReII and tetrahedral M corners bridged by cyanide ligands.

Magnetic anisotropy in two- to eight-coordinated transition–metal complexes: Recent developments in molecular magnetism

“…Dunbar et al investigated the magnetic properties of a series of mononuclear Re II complexes [179,182] [177]. All of these Re II complexes are anisotropic, where g ┴ ranges between 2.30 and 2.34, while g ǁ is in the range of 0.90-1.45, and they are efficient building units for constructing molecule-based magnets [112,178,180,181]. The isoelectronic, isogeometric Ru III and heavier Os III congeners are also capable of providing strongly anisotropic magnetic exchange coupling with other paramagnetic centers [138,183,184,194,196].…”

“…Examples of low-spin d 5 complexes that exhibit considerable magnetic anisotropy mainly comprise Re II [112,[177][178][179][180][181][182], Ru III [138,[183][184][185][186][187][188][189], and Os III [114,138,[190][191][192][193][194][195]. The magnitude of  for free Re II ranges between 300 and 2000 cm -1 .…”

A Different 'Spin' on Rhenium Chemistry. Synthetic Approaches and Perspectives of 17-Electron Rhenium Complexes

“…[33] The strategy of utilizing second-and third-row transition-metal ions in the construction of SMM has been recently and successfully applied for the synthesis of Mo(iii)-based cyanide clusters [34,35] and in one case, for the preparation of a family of mixed-metal cyanide cubes containing octahedral Re(ii) vertices. [27,28,36] Re(ii) complexes, thus, appear as potentially useful building blocks for SMM. However, one of the problems of generating Re(ii) clusters is the lack of a synthetic strategy that allows one to produce Re(ii) precursors in a systematic manner.…”

“…It has been experimentally demonstrated that supramolecular chemistry based on Re(ii) precursors is a powerful entry into the design of molecular materials with tunable magnetic, electronic and photophysical properties. [27,28,36] However, this research requires a steady influx of new precursors and the study of both discrete molecules and their polymeric architecture. It is this fundamental problem that our research wants to tackle.…”

[NiII(tn)2]5[FeIII(CN)6]2[FeII(CN)6]·10H2O: A 3-dimensional dimetallic polymer exhibiting ferromagnetic interaction

“…Very popular as a building block is for instance the choice of [M(CN) n ] mÀ (M = Cr(III), Mn(III), Fe(III), Fe(II), Ni(II)) complexes, because cyanide is an ambidentate ligand capable of bridging two metal centers in an asymmetric mode. Recognition of the ability of the cyano group to bridge two metal centres and to promote ferromagnetic interactions has led to the application of hexacyanometallates as building blocks for bimetallic assemblies with 1-D chain, 2-D sheet and 3-D lattice structures and showing novel magnetic properties [3][4][5][6][7][8][9][10]. The most outstanding and long-known example of such behavior is represented by the mixed-valence polymeric structure of Prussian [11], Prussian blue analogues, derived from self-assemblies of the anionic block [Fe(CN) 6 ] 3À and the cationic fragments (NiL 2 ) 2+ (L = ethylenediamine derivative) have attracted increasing attention due to their potential to integrate molecular-based magnets [4b,5a].…”