Konfigurationsisomerie in Polyoxovanadaten

Abstract

Ein wasserlöslicher Abkömmling des Polyoxovanadat‐Archetyps {V15E6O42} (E=Halbmetall) ermöglicht die Untersuchung supramolekular induzierter Clusterschalen‐Umwandlungen. Eine für E=Sb spezifische Reaktion, die durch einen Ligandenaustausch in [Ni(ethylendiamin)3]2+‐Gegenionen eingeleitet wird, resultiert in der Bildung des metastabilen α1*‐Konfigurationsisomers des {V14Sb8O42}‐Clustertyps. Im Unterschied zu allen bisher bekannten Polyoxovanadat‐Schalenarchitekturen weist dieses Isomer eine nach innen ausgerichtete Vanadylgruppe auf und ist ca. 50 bzw. 12 kJ mol−1 energiereicher als die zuvor isolierten α‐ und β‐Isomere. Diese unerwartete Reaktion wird im Hinblick auf supramolekulare Sb‐O⋅⋅⋅V‐ und Sb‐O⋅⋅⋅Sb‐Bindungen diskutiert, die sich in {V14Sb8O42}2‐Dimeren im Festkörper manifestieren. ESI‐MS‐Experimente untermauern die Stabilität dieser Dimere auch in Lösung und in der Gasphase. DFT‐Rechnungen zufolge sollten so auch weitere, bislang noch nicht gefundene {V14Sb8}‐Isomere zugänglich sein.

Composition-driven archetype dynamics in polyoxovanadates

“…A Hirshfeld surface analysis was performed using Crystal Explorer 17 for gaining more detailed insight into intermolecular interactions. [95][96][97][98][99][100] In this approach, a Hirshfeld surface is mapped over d norm which is dened as: Based on our recent experience with Sb-POVs containing [M(en) 3 ] 2+ cations (M ¼ Ni 2+ , Zn 2+ ), 25,39,40,102 we investigated whether the title compound is soluble in different solvents. The best solubility is observed for water (Fig.…”

Soluble Hetero‐Polyoxovanadates and Their Solution Chemistry Analyzed by Electrospray Ionization Mass Spectrometry

“…They lead to a steric hindrance around the heteroatom and can act as potential bonding partners . The known Sb‐POVs can be described with the archetypal {V 18 O 42 } by formal substitution of two, three or four VO 5 pyramids by two, three or four handle‐like Sb 2 O 5 moieties resulting in the most common {V 16 Sb 4 O 42 }‐, {V 15 Sb 6 O 42 }‐ and {V 14 Sb 8 O 42 }‐types (Figure ).…”

“…Depending on the arrangement of the vanadium skeleton, different structural isomers exist, whereas numerous more are imaginable and density functional theory calculations confirm their feasibility . During the past decades, Sb‐POVs were only accessible under hydrothermal or solvothermal conditions with low‐molecular vanadium sources like V 2 O 5 , NH 4 VO 3 , NaVO 3 and VOSO 4 or even vanadium halides.…”

“…Moreover, the Ni‐{V 15 Sb 6 } 10 proved to be a suitable precursor for an interesting supramolecular Sb‐POV architecture. The reaction of this compound with cyclen in aqueous solution yields {Ni(cyclen)(en)} 2 [V 14 Sb 8 O 42 (H 2 O)]⋅≈10 H 2 O ( 11 ) after a short reaction time . The compound has undergone a ligand metathesis and the {V 15 Sb 6 O 42 }→{V 14 Sb 8 O 42 } transformation.…”

“…Interestingly, a CID tandem MS experiment performed on an ion derived from a dimeric cluster complex revealed a remarkable binding energy connecting the two α 1 * monomers also in the gas phase. Although the very prominent cleavage of the dimeric ion into monomers is clearly favored by the reduction of charge repulsion, the characteristic loss of neutral water and hydroxyl radicals from the dimer ions yielding still‐intact dimeric product ions was also observed (Figure c) …”