Amalia Galán

Molecular recognition of organic acids and anions — Receptor models for carboxylates, amino acids, and nucleotides

The roots of synthetic molecular recognition and supramolecular chemistry itself lie in the investigation of organic ligands for metal cations, and the amount of research done in this field is overwhelming. For a long time, however, far less interest has been focussed on the complexation of anions even if the primal strategies were comparable, and only in recent years have the advances made been increasingly dynamic. In particular receptor molecules for biorelevant species such as amino acids and nucleotides are primary research targets, not least for their potential applications in medicine. In this article the developments which have been made here so far will be summarized and the attentive reader might notice that most of the primary literature cited is less than five years old. The emphasis has not been laid upon structural characteristics or synthetic strategies but rather on the effects the new host molecules give rise to and the functions they may have.

Selective complexation of adenosine monophosphate nucleotides by rigid bicyclic guanidinium abiotic receptors

Abstract Extraction of AMP nucleotides by receptors 2 and 3 from water to chloroform takes place selectively to a 0–50% extent. Receptor 5 binds AMP nucleotides by simultaneous ion-pairing, Hoogsteen H-bonding and aromatic π-π stacking.

Total synthesis of non-natural compounds for molecular recognition. The double challenge

Molecular recognition of biomolecules by synthetic receptors requires modular assembly of various components to complement the molecular characteristics (sizes, topologies, and functional groups) of the substrate. A number of receptors for biorelevant molecules containing oxoanions have been assembled from a bicyclic chiral guanidine subunit. Several receptors accelerate or catalyze reactions proceeding through anionic transition states. Among the structures recently prepared, a receptor incorporating a calix(6)arene subunit has been developed, showing high affhity for phosphocholine derivatives. Chains of tetraguanidinium sulfates form double helices in solution. These substances strongly induce formation of a-helical conformations in Asp rich peptides.

Replication and assembly

Molecules bearing surfaces capable of recognition phenomena can be covalently attached to each other to give self-complementary structures. Such molecules can reveal autocatalytic effects as replicators, and they are able to assemble in a variety of superstructures. Closed-shell assemblies, capable of inclusion phenomena are particularly desirable targets for synthetic and nucleation studies.

Synthesis and rotational properties of a series of polyaromatic clefts

Abstract A series of molecular clefts containing convergent functional groups has been developed. The rotational processes occurring within these molecules have been investigated by dynamic NMR experiments and these results are compared with those obtained from molecular modelling.

Synthesis and Complexing Properties of Chiral Guanidinium Receptors Designed for Molecular Recognition of Anions

In sharp contrast to the well established host-guest chemistry of cations, anion-binding hosts have been developed only recently, and less than 1% of the current host-guest literature is devoted to their coordination, despite the obvious importance of anions in chemistry and biology [1].