Emergence of chirality and structural complexity in single crystals at the molecular and morphological levels

Abstract

Naturally occurring single crystals having a multidomain morphology are a counterintuitive phenonomon: the macroscopic appearance is expected to follow the symmetry of the unit cell. Growing such crystals in the lab is a great challenge, especially from organic molecules. We achieve here uniform metallo-organic crystals that exhibit single crystallinity with apparently distinct domains and chirality. The chirality is present at both the molecular and macroscopic levels, although only achiral elements are used. "Yo-yo"-like structures having opposite helical handedness evolve from initially formed seemingly achiral cylinders. This non-polyhedral morphology coexists with a continuous coordination network forming homochiral channels. This work sheds light on the enigmatic aspects of fascinating crystallization processes occurring in biological mineralization. Our findings open up opportunities to generate new porous and hierarchical chiral materials.

Chiral and SHG-Active Metal–Organic Frameworks Formed in Solution and on Surfaces: Uniformity, Morphology Control, Oriented Growth, and Postassembly Functionalization

“…We previously reported the formation of paradoxical multidomain single crystals formed from a similar ligand (having triple instead of double carbon–carbon bonds) and Cu(NO 3 ) 2 . 66 Although morphologically completely different, these crystals have a molecular packing nearly identical to the crystals reported here. These observations show that varying the anion (Br – , Cl – , NO 3 – , and OAc – ) and metal cation (Cu vs Ni) in the presence of these ligands results in varied morphologies (shape, mono- to multidomain) and dimensions while retaining a high level of uniformity and nearly identical crystallographic structures.…”

“…The use of different coordinative counteranions (Br – , Cl – , NO 3 – , and OAc – ), metal cations (Ni 2+ , Cu 2+ ), growth conditions, and similar ligands (having triple instead of double carbon–carbon bonds) results in nearly identical chiral framework structures. 66 These observations indicate that a new class of chiral crystals is achievable using metal cations known to form an octahedral molecular geometry with four pyridine moieties in plane. Although the crystallographic structures are nearly identical, the crystals can take on many sizes and forms, ranging from achiral mono- to chiral multidomain morphologies.…”

“… 65 On the basis of copper and nickel salts, they assume various forms including rare single crystals having a multidomain “yo-yo-like” appearance. 66 These unique enantiopure crystals are formed from achiral components, and their growth progresses with striking morphological changes. We have also demonstrated the metal-mediated formation of fused and hollow organic crystals.…”

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

“…The shaping processes are mainly restricted to crystals with canonical frameworks and their fundamental aspects are poorly understood 20 . Our group has recently shown that a variability of uniform metallo-organic crystals with different morphologies can be obtained 28 – 30 . These studies include the formation of a unique yoyo -shaped, single crystal exhibiting both a multidomain and chiral morphology 30 .…”

Surfactant‐Mediated Morphological Evolution of MnCo Prussian Blue Structures

“…Thus, the difference in the relative growth rate between the (111) face and the (100) face becomes small with time and the size of the crystals tends to be more uniform. We learn that the reaction process of nucleus growth is mainly controlled by thermodynamics, [ 37 ] so the (100) faces with lower surface energy are more thermodynamically stable, while the (111) faces will be dissolved during the reaction due to its instability. Therefore, eight corners of the PBA‐I corresponding to the (111) face are selectively etched to give a type of cross‐sectional crystal of PBA‐II.…”