Elsevier

Inorganica Chimica Acta

Volume 363, Issue 13, 25 October 2010, Pages 3376-3383
Inorganica Chimica Acta

Synthesis, structural characterization and electrochemical activity of oxidovanadium(IV/V) complexes of a diprotic ONS chelating ligand

https://doi.org/10.1016/j.ica.2010.06.025Get rights and content

Abstract

The present work reports the chemistry of a few oxidovanadium(IV) and (V) complexes of the ONS chelating ligand S-benzyl-β-N-(2-hydroxyphenylethylidine) dithiocarbazate (H2L). Major objective of this work is to arrive at some general conclusions about the influence of binding environment generated by the replacement of an O-donor center by a S-donor point in a ligand (of a similar arrangement of the other O- and N-donor points) on the redox behavior and on the structural features of comparable [VO(OEt)(ONS)] and [VO(OEt)(ONO)] complexes. Synthesis, characterization by various physicochemical techniques (UV–Vis, IR, EPR and elemental analysis), exploration of electrochemical activity of the oxidovanadium(V) complex [VVO(OEt)L] (1), the mixed ligand complex [VVO(N–O)L] (3) (where N–O is the mono anion of 8-hydroxyquinoline) and a binuclear complex [VVO(OEt)L]2(μ-4,4′-bipy) (2) are reported. Similar studies on of mixed ligand oxidovanadium(IV) complexes of the formula [VVO(N–N)L] (4,5) (where N–N = 2,2′-bipy and o-phen) are also presented here. The [VVO(OEt)L] complex is pentacoordinated and distorted square pyramidal, while the [VIV(N–N)L] complexes are hexacoordinated and octahedral. Structural features of the complex 1 were compared with the corresponding aspects of the previously reported analogous complex [VVO(OEt)(ONO)] (1′).

Graphical abstract

Exploration of structural, electrochemical and chemical reactivity some new oxidovanadium(IV/V) complexes of a diprotic tridentate ONS chelating ligand is reported. Structural features, spectroscopic and electrochemical properties of the complex 1 involving a ONS donor ligand are compared with a similar type oxidovanadium(V) complex of a ONO donor ligand.

  1. Download : Download full-size image

Introduction

Compared to chemistry of vanadium ligated to various types of N–O donor ligands [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16], [17], [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33] vanadium complexes in total or partial sulfur coordination have received much less attention. It is rather surprising because some vanadium complexes in total or partial sulfur environment were known for the last three decades. Such vanadium complexes are found to be involved in conducting vanadium–sulfur materials [34], in the removal of vanadium from crude oils [35], as catalysts for oxidizing sulfides to sulfoxides [36]. The thiolato complexes containing vanadium(III) [37], vanadium(IV) [38], oxidovanadium(IV) [38], [39] and vanadium(V) [40] cores are also reported along with a structurally characterized V(V) thiolate complex [40] and the VO3+ complex [VO(SCH2–CH2)3N] [41]. A few other vanadium–sulfur systems also received limited attention [42], [43], [44], [45], [46], [47], [48], [49], [50]. From 1997 onwards Chaudhury and his group explored synthesis, structural characterization, magnetic, chemical, electrochemical and photochemical properties of oxidovanadium complexes involving a series of tridentate ONS donor ligands [51], [52], [53], [54], [55], [56], [57]. In this backdrop and in continuation of our work in the complex chemistry of vanadium in +3, +4 and +5 oxidation states [3], [10], [27], [28], [30], [31], [32], [33], specially in the form of oxidovanadium species, the present study of oxidoalkoxido containing vanadium complexes involving a ONS donor ligand are under taken. The complex [VO(OEt)L] (1) [where H2L is a diprotic tridentate ONS ligand, S-benzyl-β-N-(2-hydroxyphenylethylidine) dithiocarbazate] is pentacoordinate and so has one position vacant in the coordination octahedron which can be utilized as a substrate binding site for neutral monodentate N-heterocyclic bases and are also amenable to the formation of binuclear complexes utilizing suitable neutral exobidentate ligands like 4,4′-bipyridine. The present work reports the findings enumerated below: (a) synthesis, structural characterization, examination of chemical and electrochemical properties of the monooxidoalkoxidovanadium(V) complex [VO(OEt)L] (1), the mixed ligand oxidovanadium(V) complex [VO(N–O)L] (3), a binuclear complex [VO(OEt)L]2(μ-4,4′-bipy) (2) and the mixed ligand oxidovanadium(IV) complexes of the type [VO(N–N)L] (4,5) where H2L is a diprotic tridentate ONS donor ligand, N–O = 8-hydroxy quinoline and N–N = 2,2′-bipyridine, 1,10-phenanthroline.

Section snippets

Materials

[VO(acac)2] was prepared as described in literature [58] and was used as the source of vanadium. Reagent grade solvents were dried and distilled prior to use. All other chemicals were reagent grade, obtained from commercial sources and used without further purification. Spectroscopic grade solvents were used for spectral measurements.

Synthesis of the ligand H2L

The Schiff base ligand, S-benzyl-β-N-(2-hydroxyphenylethylidine) dithiocarbazate (H2L) was prepared by using a reported procedure [59]. Yield ∼80%, m. p. ∼148 °C.

Results and discussion

The monooxidoethoxidovanadium(V) complex [VO(OEt)L] (1) was obtained as yellowish brown crystalline solid by refluxing an equimolar solution of [VO(acac)2] and the ligand H2L in ethanol medium [(L)2− = dianion of the ONS donor ligand ] in ∼70% yield. V(IV) was found to be oxidized to V(V) during the reaction period. Similar complexes containing other coordinated alkoxides could also be prepared easily using appropriate alcohols. However, detailed characterization of the other alkoxido complexes

Conclusion

This work reports synthesis and characterization of three five coordinated distorted square planar oxidovanadium(V) complexes [VO(OEt)L] (1), the binuclear V(V)–V(V) complex [VO(OEt)L]2-μ-(4,4′-bipy) (2) and the six coordinate mixed ligand complex [VO(8-HQ)L] (3). Two six coordinate oxidovanadium(IV) complexes [VO(o-phen)L] (4) and [VO(2,2′-bipy)L] (5) are also discussed. Of these five complexes, 1 and 5 are structurally characterized by single crystal X-ray crystallography. We have recently

Acknowledgements

M.S. is grateful to the Council of Scientific and Industrial Research (New Delhi) for the award of senior research fellowship. We thank EPSRC and the University of Reading for funds for the Image Plate System.

References (66)

  • A. Butler et al.

    Coord. Chem. Rev.

    (1991)
  • J. Dai et al.

    Polyhedron

    (1994)
  • D. Schulz et al.

    Inorg. Chim. Acta

    (1995)
  • G. Asgedom et al.

    Polyhedron

    (1996)
  • S.P. Rath et al.

    Inorg. Chim. Acta

    (1997)
  • M.S. Palacios et al.

    Polyhedron

    (1997)
  • M. Chatterjee et al.

    Polyhedron

    (1998)
  • C. Tsiamis et al.

    Polyhedron

    (2000)
  • C. Grüning et al.

    Inorg. Chem. Commun.

    (1999)
  • G. Christou et al.

    Polyhedron

    (1989)
  • R.L. Dutta et al.

    J. Inorg. Nucl. Chem.

    (1966)
  • S.P. Cramer, in: Biochemical Application of X-ray Absorption Spectroscopy, in: D. Kouningsberger, R. Prins (Eds.),...
  • J.M. Arber et al.

    Biochemistry

    (1989)
  • A. Maity et al.

    J. Inorg. Chem. Biochem.

    (1989)
  • A.R. Bulls et al.

    J. Am. Chem. Soc.

    (1990)
  • D. Chasteen, Vanadium in Biological Systems, Kluwer Academic Publishers, Dordrecht, The Netherlands,...
  • C.J. Carrano et al.

    Inorg. Chem.

    (1990)
  • D. Rehder

    Angew. Chem. Int., Ed. Engl.

    (1991)
  • C.R. Cornman et al.

    Inorg. Chem.

    (1992)
  • A. Maity et al.

    Proc. Indian Acad. Sci.

    (1992)
  • E.M. Armstrong et al.

    J. Am. Chem. Soc.

    (1993)
  • V. Vergopoulos et al.

    Inorg. Chem.

    (1993)
  • M.J. Clague et al.

    Inorg. Chem.

    (1993)
  • D.C. Crans et al.

    J. Am. Chem. Soc.

    (1994)
  • C.J. Carrano et al.

    Inorg. Chem.

    (1994)
  • K.K. Nanda et al.

    Inorg. Chem.

    (1995)
  • C.R. Cornman et al.

    Inorg. Chem.

    (1995)
  • G.J. Coplas et al.

    J. Am. Chem. Soc.

    (1996)
  • A.D. Kemaridas et al.

    Inorg. Chem.

    (1996)
  • H. Schmidt, M. Bashipoor, D. Rehder, Dalton Trans. (1996)...
  • W. Wei et al.

    Polyhedron

    (1996)
  • M. Chatterjee et al.

    Transition Met. Chem.

    (1999)
  • R. Dinda et al.

    Inorg. Chem.

    (2002)
  • Cited by (32)

    • New pillared dioxomolybdenum(VI) complexes with ONS donor ligands and 4,4′-azopyridine spacer: 3D metal-organic supramolecular architectures and DFT calculations

      2016, Inorganica Chimica Acta
      Citation Excerpt :

      The molybdenum complexes of S-benzyl and S-methyl dithiocarbazate Schiff base ligands derived from ortho-hydroxyl aldehydes and ketones have been widely studied [1–5].

    View all citing articles on Scopus
    View full text