Guest Binding Subtly Influences Spin Crossover in an FeII4L4Capsule

Spin state switching of metal complexes by visible light or hard X-rays

Different kinds of stimuli to induce spin crossover in iron compounds are covered, focusing on electromagnetic irradiation-induced spin state switching phenomena in mono- as well as multinuclear coordination compounds.

Enhanced kinetic stability of [Pd2L4]4+ cages through ligand substitution

[Pd₂(tripy)₄]⁴⁺ cage architectures (where tripy = 2,6-bis(pyridin-3-ylethynyl)pyridine) were made more kinetically robust in the presence of range of nucleophiles by the addition of amino groups in either the 2-(2A-tripy) or 3-(3A-tripy) positions of the tripy ligands' terminal pyridines, with the [Pd₂(2A-tripy)₄]⁴⁺ cage proving the most stable.

Controllable Coordination Self-Assembly Based on Flexible Tripodal Ligands: From Finite Metallocages to Infinite Polycatenanes Step by Step

This article describes the developments in coordination self-assembly based on flexible tripodal ligands with different metal species. Various finite metallocages such as M3 L2 , M6 L8 , M6 L4 , M4 L4 and different catenanes based on discrete metallocages constructed from flexible tripodal ligands with suitable metal species are presented here. Many M3 L2 metallocages based on ligands L(1) -L(12) and different two-coordinated metal species have been prepared, in which various Ag(I) salts and other metal species that have been protected by suitable groups, such as Zn(OAc)2 , ZnBr2 , and PdBr2 , have been used as effective acceptors. All of the M6 L8 -type metallocages are constructed from ligands L(2) or L(12) -L(20) and different four-coordinated metal species, such as various palladium(II) salts or NiCl2 , and have similar topological structures. Only a few discrete M6 L4 -type metallocages, based on ligands L(21) -L(24) , have been reported, using different strategies such as protecting groups and steric hindrance. All of the M4 L4 -type cages have similar topological structures and are constructed from ligands L(25) -L(29) with multiple donor sites. More intriguing interlocking ensembles constructed from discrete metallocages are also described here in detail, namely, three [2]catenanes based on ligands L(30) -L(32) and four polycatenanes based on ligands L(33) -L(34) .

Chiral tetrahedral iron(ii) cages: diastereoselective subcomponent self-assembly, structure interconversion and spin-crossover properties

Tetrahedral chiral iron(ii) cages with spin crossover behaviors can be almost quantitatively formed by one-pot subcomponent self-assembly with high diastereoselectivity. The cage to cage transformation involving imine exchange was discovered.

An iron(ii) spin-crossover metallacycle from a back-to-back bis-[dipyrazolylpyridine]

Iron(ii) and zinc(ii) complexes of bis[2,6-di(pyrazol-1-yl)pyrid-4-yl]disulfide assemble into tetranuclear metallacycles according to ES-MS, DOSY NMR and conductivity data. The iron complex exhibits a thermal spin-state equilibrium in solution, which the iron centres appear to undergo independently of each other.

Spin crossover with thermal hysteresis: practicalities and lessons learnt

Memory applications of spin crossover require bistability: magnetic data must be appropriately collected and reported, and consideration given to lifetimes.

‘Click’ to functionalise: synthesis, characterisation and enhancement of the physical properties of a series of exo- and endo-functionalised Pd2L4nanocages

Facile CuAAC ‘click’ chemistry has been utilised toexo-functionalise Pd₂L₄host nanocages with electrochemically active, emissive and solubilising groups.

Predicting paramagnetic 1H NMR chemical shifts and state-energy separations in spin-crossover host–guest systems

The behaviour of metal–organic cages upon guest encapsulation can be difficult to elucidate in solution.

Solvent Dependent Spin-State Behaviour via Hydrogen Bonding in Neutral FeII Diimine Complexes

We report the syntheses, structures, and magnetic properties of cis-[Fe(pizR)2(NCS)2] complexes based on the pyridyl imidazoline ligands 2-(2′-pyridinyl)-4,5-dihydroimidazole (pizH, 1) and 2-(2′-pyridinyl)-4,5-dihydro-1-methylimidazole (pizMe, 2). The ligands, complexes, and magnetic measurements are chosen to separate hydrogen-bonding and intrinsic ligand field properties, so as to improve our understanding of the effect of hydrogen-bonding interactions on spin-state switching. In the solid state, both complexes are high spin between 5 and 300 K. In deuterated methanol and acetonitrile solutions, both complexes show gradual thermal spin crossover. Complex 1, capable of hydrogen bonding, shows solvent-sensitive spin crossover, whereas spin crossover in the methylated analogue 2 is insensitive to solvent identity.

Self-Assembly of an Octanuclear High-Spin FeII Molecular Cage

A discrete octanuclear high-spin FeII cage [Fe8L12](BF4)16·n(solvent) was synthesised via metal ion-directed self-assembly. The cage formation is facilitated by incorporating a relatively flexible ditopic ligand with chelating pyrazolyl–pyridine functional units. The synthesis, structure, and magnetic properties of this metallo-cage are presented.