A Decavandate Sandwiched by Diprotonated Cryptands‐222: Model for the Vanadate‐Ionophore Interaction

Abstract

Treatment of a C222‐vanadyl‐AMP complex (C222 = cryptand‐222, AMP = adenosine monophosphate) with Me2NH in the presence of air yielded centrosymmetric dihydrogen‐decavanadate H2V10O428, sandwiched by two diprotonated C222 molecules. An X‐ray crystal‐structure analysis was performed of this compound with the overall composition [C222(H+)2]2[H2V10O28] · 2 1/2, H2O. Protonation sites in the anion are μ2‐oxygen atoms linking two different vanadium centres. Protonation sites at the cryptand are the nitrogen and/or oxygen atoms of one of the −[CH2]2O[−CH2|2O|CH2]– bridges. The relevance of the compound for the stabilisation and transport of the kinase and phosphatase inhibitor decavanadate by biogenic ionophores is addressed.

Host–Guest Complexes of Oligopyridine Cryptands: Prediction of Ion Selectivity by Quantum Chemical Calculations

“…[38] [a] Computer Chemistry Center, University of Erlangen-Nürnberg, Nägelsbachstrasse 25, agents, [18] and as models for carrier-antibiotics such as Valinomycin and enzyme inhibitors. [19] In contrast, the cryptands 6,6Ј,6ЈЈ,6ЈЈЈ,6ЈЈЈЈ,6ЈЈЈЈЈ-bis[nitrilotri(methylene)]tris-(2,2Ј-bipyridine) (1) and 2,2Ј,2ЈЈ,9,9Ј,9ЈЈ-bis[nitrilotri(methylene)]tris(1,10-phenanthroline) (2) are systems that have only been partially investigated (see Figure 1). In the 1984 report on the first synthesis of cryptands, two project aims for these newly designed polypyridine cryptands were expressed: (i) as ligand systems with novel metal-ion binding properties and (ii) special photophysical/ photochemical properties for electron-transfer processes.…”

Hetero and lacunary polyoxovanadate chemistry: Synthesis, reactivity and structural aspects

“…Theoretically, the special cell compartment where vanadium may be accumulated is able to stabilize polyoxovanadates through hydrogen bond formation. The protonation of decavanadates allows them to interact with numerous biological molecules such as proteins through hydrogen bonds [7]. These interactions can result in the fomation of a protective cage in the cell that harbors inorganic decavanadates without decomposition.…”

[3.2.1] and [4.1.1] isomers of Lehn's [2.2.2] Cryptand: Prediction of ion selectivity by quantum chemical calculations XV**

“…This discovery granted Lehn together with Pedersen and Cram a Nobel Prize in 1987, [3] and to the field of supramolecular encapsulation chemistry the legacy to pursuit for optimizing and better understanding of the systems that represent it. Today some of these compounds have found their application in numerous fields, such as: phase-transfer catalysis, [4] selective complexation of radioactive or toxic ions in medicine, [5] studies on Zintl phases, [6] models for carrier-antibiotics such as Valinomycin and enzyme inhibitors, [7] and as a ligand for MRI contrast agents. [8] The unmatched selectivity of Lehn-type diaza-polyether cryptands for encapsulation of complementary sized metal cations guests [9] are attributed to great thermodynamic and kinetic stabilities.…”