Tetramere Dioxo‐oxalato‐Komplexe des Vanadins(V). Die Kristallstruktur von K[VO₂(C₂O₄)] · 2H₂O

Abstract

a b c d e f N a K NH4 Rb Cs 1/2Sr Eingegangen am 20. Oktober 1975 Die roten Dioxo(oxalato)vanadate(V), M'[V02(C204)] . n H 2 0 (M' = Na, K, NH4, Rb, 112 Sr) enthalten, wie durch eine Rontgenstrukturanalyse an K[V02(C204)] . 2 HzO ermittelt wird, das tetramere, cyclische Anion [{V02(CZ04)}4(H20)2]4-. Alle Vanadinatome sind oktaedrisch von einem endstandigen und zwei verbriickenden Sauerstoffatomen, von einem Wassermolekiil und einem Oxalat-Ion als zweizahnigem Ligand koordiniert. Je 2 Oktaeder sind iiber eine gemeinsame Kante zu einem Paar verkniipft ; zwei Paare bilden dann iiber zwei einfache Sauerstoffbriicken (Spitzenverkniipfung) die tetramere Einheit.

Stepwise Cluster Assembly Using VO2(acac) as a Precursor: cis-[VO(OCH(CH3)2)(acac)2], [V2O2(μ-OCH3)2(acac)2(OCH3)2], [V3O3{μ,μ-(OCH2)3CCH3}2(acac)2(OC2H5)], and [V4O4(μ-O)2(μ-OCH3)2(μ3-OCH3)2(aca

“…As expected, the doubly bridging methoxide ligands (O5, O5a) in the V 4 O 4 framework exhibit V−O bond distances (1.950(4), 2.004(4) Å) longer than the V−O distances for the bridging oxo ligands (O6, O6a) (1.747(4), 1.911(4) Å). The average V−O(oxo) bond lengths (average 1.83(4) Å) are similar to those in other tetramers with V 4 O 4 frameworks, including [V 4 O 8 (OCH 3 ) 4 (bipy) 2 ] (1.84(11) Å), [V 4 O 8 (O 2 CH 2 t Bu)] (average 1.85(9) Å), and [V 4 O 8 (C 2 O 4 ) 4 (H 2 O) 2 ] 4- (average 1.81(3) Å) . The two types of V−O−V bond angles in the V 4 O 4 framework involving singly bridging oxygen atoms are very similar (V1−O6−V2 = 114.7(2)°, V1−O5−V2 = 114.3(2)°), despite the differences in bond lengths noted.…”

Syntheses, X-ray Structures, and Solution Properties of [V4O4{(OCH2)3CCH3}3(OC2H5)3] and [V4O4{(OCH2)3CCH3}2(OCH3)6]: Examples of New Ligand Coordination Modes

“…In Figure b one of the four reported “boat” modes is shown; the polyhedral core consists of two pairs of edge-sharing octahedra linked by two corner-sharing oxygen atoms. This geometry was reported in [V 4 O 4 (C 2 O 4 ) 4 (H 2 O) 2 ] 4- the polyhedral core consists of four corner-sharing [VO 5 ] units and four edge-sharing [VO 6 ] units, respectively.…”

“…Previous reports of vanadium complexes with the thme 3- ligands generated binuclear, hexanuclear, and decanuclear complexes ,− in contrast to the family of complexes described in this work. While this work was in progress several reports of the structural characterization of related oxometalate systems appeared allowing a comparison of all the complexes currently available with this ligand. ,− Among the tetranuclear oxovanadium complexes reported elsewhere ,− and in this work, several types of metal and ligand connectivities can be identified, demonstrating the wide range of structural possibilities that are stable and tractable for these types of complexes. Although these complexes only contain four metal ions, it is becoming clear that even these simple oxometalates can support a wide range of structures. , In this work we report four new complexes and solution studies in order to explore not only the new oxometalates and their form in solution, but also their reactivity toward exchange and hydrolytic reactions.…”

“…There are, however, two fundamentally different types of edge-sharing polyhedral modes, the “chair” mode described in this work, and a “boat mode”. The tetramers [V 4 O 8 (NO 3 )(tca) 4 ] 2- , [V 4 O 8 (C 2 O 4 ) 4 (H 2 O) 2 ] 4- , and [V 4 O 8 (O 2 CCH 2 t Bu) 4 ] 25 contain four vanadium atoms in a single plane and in a “boat” conformation. An entirely different geometry is observed for the closely related complex [V 4 O 4 (SNNS) 4 ] (where SNNS is N , N ‘-bis( o -mercaptophenyl)ethylenediamine).…”

Exchange coupling in µ-aqua:µ-oxo vs. di-µ-hydroxo dinuclear Cu(ii) compounds: a density functional study

“…A search in the Cambridge Structural Database, 27 shows that dinuclear compounds with aqua and oxo bridges are scarce. The three examples found include two vanadium 28, 29 and one molybdenum 30 compound. For copper dinuclear compounds, besides the great number of bis l-oxo compounds, we have found some examples with hydroxo and aqua bridges [31][32][33][34][35] and a few compounds with a bis l-aqua coordination.…”