Ruthenium Containing/Grafted POMs


The existence of AsV-, PV-containing lacunary polyoxoanions has been known for long time. In the last couple of years, the AsV-, PV-based trilacunary polyoxoanions, e.g. [XW9O34]9- (X = AsV and PV) and [X2 W15O56]12- (X = AsV and PV), and their transition metal substituted sandwich-type derivatives, e.g. [M4(H2O)2(XW9O34)2]n- and [M4(H2O)2(X2W15O56)2]n- (X = AsV, PV; M = MnII, CoII, NiII, CuII, ZnII, CdII, FeIII), have been reported and structurally characterized by means of IR, UV-vis, CV, 183W NMR, TG-DSC, elemental analyses and single-crystal X-ray diffraction analyses. However, there are very few reports on the trilacunary tungstoarsenate(V) and tungstophosphate(V) functionalized by organic molecules or organo–metal complexes. More recently, Kortz’s group prepared the diorganotin group-linked trilacunary tungstoarsenate and tungstophosphate, [{Sn(CH3)2(H2O)}24{Sn(CH3)2}12(A-XW9O34)12]36- (X = AsV, PV), which is composed of 12 trilacunary [A-XW9O34]9- Keggin fragments linked by a total of 36 dimethyltin groups resulting in a polyanion with a ball-shape. The aim of our work is to functionalize the trilacunary tungstoarsenate(V) and tungstophosphate(V) by an organo-Ru complex.

In the recent years, metal Ru-substituted POMs have attracted increasing attention due to their significant reactivity and selectivity in the catalytic oxidation of various organic substrates by O2 and H2O2. In particular, recent works have documented that Ru-containing POMs are effective active catalyst for H2O oxidation to O2. Therefore, in the world several research groups have devoted different Ru-containing complexes, i.e. RuCl3·nH2O, [Ru(H2O)6][C7H7SO3]2, Ru(acac)3 and cis-Ru(DMSO)4Cl2, to synthesize Ru-based POMs. However, the number of structurally fully-characterized Ru-POMs has been reported rarely. To date, arene-Ru(II) species (arene = benzene, p-cymene, toluene etc.) have been successfully exploited for the preparation of Ru-containing POMs. Different research groups have presented a number of polymolybdates and polytungstates based on the arene-Ru(II) species, such as [{Ru(η6-C6Me6)}2Mo5O18{Ru(η6-C6Me6)(H2O)}], [{PW11O39(RuC6H6)}2{WO2}]8-, [Sb2W20O70{Ru(p-cymene)}2]10- etc. Recently, Bi and Kortz et al. isolated benzene-Ru supported trilacunary tungstosilicate/tungstogermanate [(RuC6H6)2- XW9O34]6- (X = Ge, Si) and dilacunary tungstosilicate/ tungstogermanate [{(RuC6H6)(H2O)}(RuC6H6)(g-XW10O36)]4- (X = Si, Ge). Notably, benzene-Ru groups can stabilize the lacunary polyoxoanions by their coordination to avoid lacunary species isomerization to other tungsten-oxo fragments in acidic solution. Therefore fundamental studies towards the stabilization of other lacunary clusters by benzene-Ru groups are still needed. Moreover, the potentially attractive catalytic properties of such species are a strong motivation to continue this kind of research.

Selected Publications

  • Organo-Ruthenium Supported Heteropolytungstates: Synthesis, Structure, Electrochemistry and Oxidation Catalysis
    Bi, L.-H.; Al-Kadamany, G.; Chubarova, E. V.; Dickman, M. H.; Chen, L.; Gopala, D. S.; Richards, R. M.; Keita, B.; Nadjo, L.; Jaensch, H.; Mathys, G.; Kortz, U. Inorg. Chem. 2009, 48, 10068-10077. [Read Online]
  • Synthesis and crystal structure of pseudo-sandwich-type heteropolytungstates functionalized by organometallic ruthenium(II)
    Bi, L.-H.; Hou, G.-F.; Li, B.; Wu, L.-X.; Kortz, U. Dalton Trans. 2009, 6345-6353. [Read Online]
  • Carbonyl-Ruthenium Substituted α-Keggin-Tungstosilicate, [α-SiW11O39RuII(CO)]6-: Synthesis, Structure, Redox Studies and Reactivity
    Sadakane, M.; Iimuro, Y.; Tsukuma, D.; Bassil, B. S.; Dickman, M. H.; Kortz, U.; Zhang, Y.; Ye, S.; Ueda, W. Dalton Trans. 2008, 6692-6698. [Read Online]
  • Mixed-Valence 24-Vanadophosphate Decorated with Six RuII(dmso)3 Groups: [{RuII3(dmso)9PVV11VIVRuIIIO37(OH)3}2]8-
    Bi, L.-H.; Mal, S. S.; Nsouli, N. H.; Dickman, M. H.; Kortz, U.; Nellutla, S.; Dalal, N. S.; Prinz, M.; Hofmann, G.; Neumann, M. J. Clust. Sci. 2008, 19, 259-273. [Read Online]