Cages on a plane: a structural matrix for molecular ‘sheets’

Abstract

A family of heterometallic Anderson-type ‘wheels’ of general formula [MIII2MII5(hmp)12]4+ has been extended to include MIII = Cr, Al; MII = Co, Ni, Fe, Mn, Cu and Zn, alongside the ‘extended’ [AlIII6CuII7(OH)12(hmp)12]8+.

Magnetic exchange, anisotropy and excitonic fluctuations in a [NiII7] Anderson wheel

“…15 Planar heptanuclear discs conforming to centred hexagons are often referred to as Anderson or Anderson-Evans wheels, 16 and are a common structure type in both polyoxometalate chemistry 17 and clusters of paramagnetic 3d ions. 18 A search of the Cambridge Structural Database (CSD) reveals that there are twenty nine [Ni II 7 ] Anderson wheels. [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Of these, fifteen have had their magnetic behaviour reported, but only five have been subject to quantitative analysis.…”

Influence of Semirigidity and Diverse Binding Modes of an Asymmetric Pyridine-pyrazole Based Bis-Chelating Ligand in Controlling Molecular Architectures and Their Properties

“…The design and construction of polynuclear metal cages − or clusters using the basic concepts of coordination chemistry − have gotten tremendous attention for their new exciting architectures as well as their practical applications as functional inorganic materials. − For instance, paramagnetic transition metal or lanthanide based polynuclear cage or clusters has become a highly topical area of research in the field of magnetism. − The construction of cages and clusters with desired magnetic properties, however, remains a challenging task and requires careful optimization of structural topology and its ingredients such as metal ions, ligands, and coordinating functional groups. − In principle, the magnetic materials can be constructed by incorporating magnetic moment carriers such as paramagnetic metal ions and by using suitable bridging ligands that act as a super exchange pathway, the all-important mode of magnetic interactions, between the magnetic centers. − Naturally, the nature and number of bridging sites are at the heart of the matter, when a ligand is judiciously designed. , The general aim is to connect the maximum number of metal ions within the shortest possible distance in order to generate significant magnetic interactions. Accordingly, using multidentate ligands with bridging sites such as hydroxyl/phenolic groups or N-donor atoms to construct polynuclear cage or clusters has proved highly beneficial to understand the underlying structural correlation with magnetic properties. − …”

A [Mn18] wheel-of-wheels

“…Beyond beautiful structural aesthetics, wheels of paramagnetic metal ions have proven to be vital for revealing quantum effects, 1 constructing very high spin molecules, 2 engineering toroidal magnetic moments, 3 developing magnetic Möbius strips, 4 understanding frustration effects, 5 probing slow magnetisation relaxation, 6 investigating quantum information processing, 7 and developing magneto-structural correlations. 8 In Mn coordination chemistry wheels have presented nuclearities as large as eighty-four, 9 displaying a variety of topologies constructed from chains of single metal ions and polymetallic building blocks. [10][11][12][13] Amongst ligand types, those containing one or more ethanolamine (eaH) moieties ( Fig.…”