Bio-inspired synthetic approaches: from hierarchical, hybrid supramolecular assemblies to CaCO₃-based microspheres

Abstract

A bio-inspired synthetic approach to unprecedented hybrid supramolecular assemblies [Ca(Mehda)(HO)]·HO (1) and [Ca(Chda)(HO)]·HO (2), that are stabilized by iminodiacetate-substituted organic ligands is reported. The results of the single-crystal X-ray analysis of 1 further allowed the use of electron microscopy to verify the supramolecular structure of the fibrous assemblies of 2 that incorporate extended alkyl-substituted ligand derivatives. 2 reveals interesting features that distinguish these soft structures from purely inorganic, brittle materials: meshes of nanobelts transform on solid supports to form homogeneous films covering extended, micro-sized areas. The use of the reported ligand system as a habit modifier for CaCO results in hierarchical calcite aggregates. The structure-influencing effects of the ligands and their supramolecular assemblies promote the formation of calcite disks that tessellate into hollow microspheres that contain distinctive openings.

Novel phenolic antimicrobials enhanced activity of iminodiacetate prodrugs against biofilm and planktonic bacteria

“…Parent phenols 1a–t were transformed into three basic architectural motifs corresponding to the structures 2a–o , 3a–c , and 4a,b . AM derivatives of the types 2 and 3 were prepared by modifications of the classical “phenol‐Mannich” condensation (d'Hardemare, Jarjayes, & Mortini, 2004; Marzec, Zhang, Zhu, & Schmitt, 2017). The AMs 4a and 4b were synthesized by acylation of the corresponding phenols with anhydride 5 followed by cesium salt formation and alkylation with bromomethyl acetate (Scheme 1).…”

“…2‐Substituted phenolic iminodiacetates are well‐known for forming chelate structures where the hydroxyl function is ligated to the metal cation (i.e., Ca +2 ; d'Hardemare et al, 2004; Huitink et al., 1974; Kerber, Goheen, Perez, & Siegler, 2016; Marzec et al., 2017; Schwarzenbach, Sallmann, & Komplexone, 1952; Stabnis, 2010; Tarn, Xue, & Zink, 2013). In contrast, for iminodiacetates corresponding to 3a–c and 4a/b , internal coordination of the phenolic hydroxyl would not be expected.…”

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…Synthetic CaCO 3 structures stabilized by iminodiacetate‐substituted organic ligands such as 2,2ʹ‐(2‐hydroxybenzylazanediyl)diacetic acid (hda) led to supramolecular coordination assemblies that self‐organized into hierarchical calcite aggregates, some of these having partial similarity in morphology with E. huxleyi or Gephyrocapsa oceanica coccolithophores . The synthetic coccosphere (≈10 μm in diameter) comprised a shell of 7–11 specific hollow centered calcite discs similar to the morphology, structure, and configuration of a natural coccolithophore ( Figure ).…”

“…Scale bar of 2 μm (F,G). A–E) Reproduced with permission . Copyright 2017, Royal Society of Chemistry.…”