Shaping calcite crystals by customized self-assembling pseudopeptide foldamers

Abstract

Two pseudopeptide foldamers with similar backbones, one containing a D-4-carboxy-5-methyloxazolidin-2-one moiety (1) and the other a D-proline moiety (2), self-assembled in a 9 : 1 water-ethanol mixture. Molecule 1 formed fibres that generated a highly viscous sol or a gel by increasing its concentration; molecule 2 assembled in nanoparticles that aggregated in bigger particles by increasing its concentration.This behaviour was conserved in the presence of 10 mM CaCl 2 . Both foldamers, which exposed carboxylate groups, were able to modify the shape of single crystals of calcite. The presence of molecule 1 favoured the formation of rhombohedral calcite showing additional crystalline faces, while molecule 2 induced the formation of cavities and curvatures. Thus, pseudopeptide foldamers diversely act as crystal growth modifiers according to minor structural changes that mutate their self-assembly. This result is of general interest for the design of new molecules affecting the crystallization process and has implications in understanding how biological molecules control the growth of mineral phases.

Composite Porous Liquid for Recyclable Sequestration, Storage and In Situ Catalytic Conversion of Carbon Dioxide at Room Temperature

“…The micrographs clearly showed the emergence of particles with various shapes like pseudo‐cubical, and rod‐like, which grew significantly in dimensions from ≈14.7 μm ×9.9 μm at 12 h to ≈18.5 μm×13.25 μm over 48 h (Supporting Information, Figure S8i). Interestingly, the morphology of these particles resembled with the CaCO 3 crystals as reported in the literature, [67,68] thus suggesting the conversion of CO 2 to HCO 3 − ion which subsequently reacted with Ca 2+ ions to form CaCO 3 crystals. The decrease in transmittance of PoLi‐bCA/CaCl 2 /CO 2 over a period of time as shown in Figure 2a could therefore be attributed to the formation of these CaCO 3 crystals.…”

Novel Multifunctional Porous Liquid Composite for Recyclable Sequestration, Storage and In-situ Catalytic Conversion of Carbon Dioxide

“…The micrographs clearly showed the emergence of particles with various shapes like pseudo-cubical, and rod-like, which grew significantly in dimensions from ≈ 14.7 × 9.9 µm at 12 h to ≈ 18.5 µm × 13.25 µm over 48 h (SI, Figure S8i). Interestingly, the morphology of these particles resembled with the CaCO 3 crystals as reported in the literature, 33,34 thus suggesting the conversion of CO 2 to HCO 3 ion which subsequently nucleophilic OH − , which attacks the incoming CO 2 in the second step which is followed by the formation of Zn 2+ -HCO 3 complex in the third step. Finally, the regeneration of the enzyme/active site occurs with the simultaneous release of HCO 3 ion as a result of addition of water molecule from the residual reservoir.…”

Novel Multifunctional Porous Liquid Composite for Recyclable Sequestration, Storage and In-situ Catalytic Conversion of Carbon Dioxide

“…The micrographs clearly showed the emergence of particles with various shapes like pseudo-cubical, and rod-like, which grew significantly in dimensions from ≈ 14.7 × 9.9 µm at 12 h to ≈ 18.5 µm × 13.25 µm over 48 h (SI, Figure S8i). Interestingly, the morphology of these particles resembled with the CaCO 3 crystals as reported in the literature, 33,34 nucleophilic OH − , which attacks the incoming CO 2 in the second step which is followed by the formation of Zn 2+ -HCO 3 complex in the third step. Finally, the regeneration of the enzyme/active site occurs with the simultaneous release of HCO 3 ion as a result of addition of water molecule from the residual reservoir.…”

“…The micrographs clearly showed the emergence of particles with various shapes like pseudo-cubical, and rod-like, which grew significantly in dimensions from ≈ 14.7 × 9.9 µm at 12 h to ≈ 18.5 µm × 13.25 µm over 48 h (SI, Figure S8i). Interestingly, the morphology of these particles resembled with the CaCO 3 crystals as reported in the literature, 33,34 ) resulting in the formation of CaCO 3 crystals, plausibly having pseudo-cubic structure. 37,38 In order to conclusively comment on the morphology and crystalline structure of CaCO 3 crystals we further analyzed the samples using electron microscopy and diffraction studies.…”