Molecular cannibalism: Sacrificial materials as precursors for hollow and multidomain single crystals

Abstract

The coexistence of single-crystallinity with a multidomain morphology is a paradoxical phenomenon occurring in biomineralization. Translating such feature to synthetic materials is a highly challenging process in crystal engineering. We demonstrate the formation of metallo-organic single-crystals with a unique appearance: six-connected half-rods forming a hexagonal-like tube. These uniform objects are formed from unstable, monodomain crystals. The monodomain crystals dissolve from the inner regions, while material is anisotropically added to their shell, resulting in hollow, single-crystals. Regardless of the different morphologies and growth mechanism, the crystallographic structures of the mono- and multidomain crystals are nearly identical. The chiral crystals are formed from achiral components, and belong to a rare space group (P622). Sonication of the solvents generating radical species is essential for forming the multidomain single-crystals. This process reduces the concentration of the active metal salt. Our approach offers opportunities to generate a new class of crystals.

Unusual Surface Texture, Dimensions and Morphology Variations of Chiral and Single Crystals**

“…In our case, a highly ordered, chiral structure formed from achiral molecules affording a seemingly random arranged textured surface consisting of domains that are still organized at the molecular level. Naturally occurring multidomain single‐crystals normally consists of fascinating organized structures, [67] whereas the relative few man‐made systems have similar features [41, 42] . In contrast, the here reported ovoid single crystals have randomly organized domains.…”

“…Only a few molecule‐based crystals have been reported that exhibit paradoxically both single‐crystallinity and a multidomain appearance. We reported recently two examples of such uncommon crystals [41, 42] . Their domains are large relative to the overall sizes of the crystals.…”

Single‐Handed Double Helix and Spiral Platelet Formed by Racemate of Dissymmetric Cages

“…On each platelet multiple layers propagate in aselfperpetuating fashion, and the edges of the spiral layers in each direction are all aligned parallel (Figure 5b and c), which is at ypical topological defect during crystal growth, namely screw dislocation. [47][48][49][50] During the crystal growth, this screw dislocation allows the layers of each platelet spiral either clockwise (Figure 5b,e and Figure S9) or anti-clockwise (Figure 5c,f and Figure S10). It therefore indicates symmetry breaking at morphological level, even though each platelet consists of racemic mixture of DC-1 molecules.…”

Directing both the Morphology and Packing of Chiral Metal-Organic Frameworks by Cation Exchange Mediated by Nanochannels

“…To control and predict the packing-morphology relationship, we investigated cation metathesis using a new, manganese-based MOF having the same rare P622 space-group as our other reported crystals (Scheme 1). [45][46][47][48] The crystal structure is porous and exhibits two geometrically and compositionally different channels. Cation metathesis was used here to control and Scheme 1.…”