Finding a receptor design for selective recognition of perrhenate and pertechnetate: hydrogen vs. halogen bonding

Abstract

Receptors bearing hydrogen and halogen bond donors for recognition of perrhenate and pertechnetate were designed and studied. Acyclic hosts with N-H and C-H binding sites showed the best selectivity for TcO4- and ReO4- over spherical and more basic tetrahedral anions.

Helix-Like Receptors for Perrhenate Recognition Forming Hydrogen Bonds with All Four Oxygen Atoms

“…As inferred from our previous studies [8], the acylation of p-xylylenediamine leads to the formation of two amide groups, which serve as hydrogen bond donor sites for the coordination of two oxygen atoms of perrhenate or pertechnetate anions. The distance between the amide groups of 7 Å is optimal to achieve binding complementarity between two oxygen atoms of the perrhenate anion and NH-binding sites.…”

“…The design of artificial anion receptors is a challenge in supramolecular chemistry that has received great attention in recent years [1][2][3][4][5][6], moving from being an entirely fundamental area of supramolecular chemistry to a range of applications. Perrhenate (ReO 4 − ) and pertechnetate (TcO 4 − ) are considered to be the anions that are among the most "difficult to bind" due to their relatively large size and low charge density [7,8]. These anions are available from 99 Mo/ 99m Tc and 188 W/ 188 Re generators and are widely used in nuclear medicine as a part of diagnostic imaging tools and therapeutic devices [9][10][11].…”

“…Several approaches have been recently explored to bind or extract the anions in question: the design of synthetic receptors [16][17][18][19][20][21][22][23][24][25][26], fluorescent probes [27,28], and inorganic materials [29][30][31][32][33][34]. In our recent study, we have elucidated how the nature of the binding sites influence the overall binding affinity of receptors [8]. The studied receptors coordinated only two oxygen atoms of ReO 4…”

“…The design of the receptor consists of a rigid Chemosensors 2021, 9, 93 2 of 11 helix-forming subunit derived from 1,1 -ferrocenedicarboxylic acid, 1,3-phenylenediacetic acid and 2,2 -(ethyne-1,2-diyl)dibenzoic acid (Figure 1). These subunits are equipped with a 2,6-pyridine dicarboxamide moiety connected through p-xylylenediamine spacers, which have been proven in our previous work [8] to generate optimal distance between NH-binding sites. Among three new synthesized receptors, the receptor with a diphenylacetylene helix-forming subunit has demonstrated the best affinity and selectivity for the perrhenate anion.…”

5,5-Dichloro-6-hydroxydihydropyrimidine-2,4(1H,3H)-dione: molecular and crystal structure, Hirshfeld surface analysis and the new route for synthesis with Mg(ReO4)2 as a new catalyst

“…Typically, ReO 4 À does not react with HCl while TcO 4 À is actively reduced (German et al, 2002). We found that in the presence of Mg 2+ , the ReO 4 À being distorted according to (Khrustalev, 2000;Ravi et al, 2018) attacks the HCl, forming Cl 2 that is readily reacted with water to form HOCl. In the air and in low acidic HClÁH 2 O solution, the Re is then oxidized back to Re VII .…”