Sterics and metal-ion radius control the self-assembly of [M₂L₃] helicates

Abstract

The interplay of many factors influences the outcomes of self-assembly reactions. Using an acetylene-appended quaterpyridine ligand we show that both the size of metal ion and the presence of steric...

Tuning the spin-crossover properties of FeII4L6 cages via the interplay of coordination motif and linker modifications

“…45 We attribute the formation of Zn 2 L 3 but not Fe 2 L 3 helicates to a combination of the metal's ionic radius and ligand's steric bulk increasing the energy of the Fe 2 L 3 relative to the Fe 4 L 6 self-assembly, as has been observed in related systems. 46,47…”

“…45 We attribute the formation of Zn 2 L 3 but not Fe 2 L 3 helicates to a combination of the metal's ionic radius and ligand's steric bulk increasing the energy of the Fe 2 L 3 relative to the Fe 4 L 6 self-assembly, as has been observed in related systems. 46,47 The spin-crossover properties of cages 1-11 were investigated in solution between 248 K and 348 K in CD 3 CN. While the Evans method 48 can determine the magnetic susceptibility from variable-temperature (VT) NMR experiments, preliminary studies with cage 6 showed the NMR signals shifted upon addition of the p-xylene standard, suggesting possible guest binding (Fig.…”

Dynamic Stereochemistry of M8Pd6 Supramolecular Cages Based on Metal‐Center Lability for Differential Chiral Induction, Resolution, and Recognition

“…As the proteins are intrinsically dynamic, metal cations of distinct labile nature can provide a valuable source to investigate dynamic properties of the assembled cages for protein‐mimicking, allowing twisted configurations around metal centers to increase diversity of cage structures [7] with stereochemical merits [7a,8] . The six‐coordinated first‐row transition metals, such as Fe 2+ , Ni 2+ and Zn 2+ , have been widely applied in cage assembly, focusing on the shape and size control of the cage containers; [3l,9] however, their significance in cage dynamics and functions should not be neglected [3k,10] . When it comes to a large cage composed of multiple metal centers, the tiny change on individual metal center may be amplified or synergized, leading to macroscopically visible disparities.…”

Remote stereocentres do not disrupt the stereochemical coupling in homochiral [M2L3] helicates and [M4L6] tetrahedra

“…41,42 When metal ions with larger ionic radii were employed, helical assemblies could be exclusively formed with L 1 . 43 In each of these assem-blies, the strong positive stereochemical communication between octahedral metal centres was not disrupted by the steric bulk of the acetylene groups resulting in homochiral assemblies. Here we present chiral derivatives of L 1-2 in which resolved stereogenic centres have been introduced through a copper(I) catalysed 1,3-cycloaddition (L [3][4] ).…”

“…S8 †), approximately the same size as observed for related helicates. 43 Red crystals, suitable for X-ray structure determination, were grown by methanol diffusion into a solution of the iron(II) complex in acetonitrile. The product crystallised in space group P2 1 and the asymmetric unit contains both S,S,S, S,S,S,ΔΔ-[Fe 2 L 3 3 ] 4+ and S,S,S,S,S,S,ΛΛ-[Fe 2 L 3 3 ] 4+ diastereomers of the complex (Fig.…”