Elsevier

Polyhedron

Volume 25, Issue 17, 4 December 2006, Pages 3238-3244
Polyhedron

Synthesis, spectroscopic characterization and structural studies of bromodioxodimethylsulfoxide (N,N′-dialkyldithiocarbamates and O-alkyl dithiocarbonate)molybdenum(VI) complexes: Crystal structures of MoO2Br2(OSMe2)2 and MoO2Br2(C12H8N2) · CH2Cl2

https://doi.org/10.1016/j.poly.2006.05.034Get rights and content

Abstract

Reactions of dibromodioxobis(dimethylsulfoxide)molybdenum(VI) with sodium/potassium salts of N,N′-dialkyl dithiocarbamates or O-alkyl dithiocarbonates in 1:1 molar ratio in dichloromethane yield bromodioxomolybdenum(VI) complexes of the type, MoO2Br(S2CNR2)(OSMe2) (R = Et, Prn, Pri) or MoO2Br(S2COR)(OSMe2) (R = Et, Prn, Pri). These newly synthesized complexes were characterized by elemental analysis and IR, UV–Vis and 1H NMR spectroscopy. Crystals of MoO2Br2(OSMe2)2 and MoO2Br2(C12H8N2) · CH2Cl2 both have distorted octahedral environments around molybdenum with two cis-oxygen atoms and two trans-bromine atoms along with two cis-dimethylsulfoxide moieties in the former and 1,10-phenanthroline in the latter.

Graphical abstract

Reactions of dibromodioxobis(dimethylsulfoxide)molybdenum(VI) with sodium/potassium salts of N,N′-dialkyl dithiocarbamates or O-alkyl dithiocarbonates yield bromodioxomolybdenum(VI) complexes of the type, MoO2Br(S2CNR2)(OSMe2) or MoO2Br(S2COR)(OSMe2). Crystals of MoO2Br2(OSMe2)2 and MoO2Br2(C12H8N2) · CH2Cl2 have distorted octahedral environments around molybdenum with two cis-oxygen atoms and two trans-bromine atoms in both along with two cis-dimethylsulfoxide moieties in the former and 1,10-phenanthroline in the latter.

  1. Download : Download full-size image

Introduction

The potential role of high oxidation state oxomolybdenum(VI) complexes as model systems in molybdoenzymes [1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], as oxo transfer agents [12] and as catalyst precursors e.g. in the selective epoxidation of olefins [13] prompted us to work with higher valent molybdenum complexes. In contrast to other metals active in biological systems, the oxidation state of molybdenum in such systems is generally high, usually +5 or +6. Crystal structures of MoO2X2 · 2OPPh3 (X = Cl, Br) [14], MoO2Cl2 · 2DMSO [15], [16] and model studies for molybdoenzymes on MoO2X2 · 2L (X = Cl, Br; L = OPPh3) have been reported [14]. An improved role in oxygen transfer reactions [9], [17] has been suggested for air stable dioxomolybdenum(VI) complexes derived from their air sensitive precursors MoO2Cl2 and MoO2Br2. Our continuing interest in oxomolybdenum(VI) complexes has led to this report on the reactions of dibromodioxobis(dimethylsulfoxide)molybdenum(VI) complexes with sodium or potassium salts of N,N-dialkyl dithiocarbamate and O-alkyl dithiocarbonate to yield complexes such as MoO2Br(S2CNR2)(OSMe2) and MoO2Br(S2COR)(OSMe2) along with their characterization by various spectroscopic techniques. We also report on the synthesis and X-ray crystal structures of MoO2Br2(OSMe2)2 and MoO2Br2(C12H8N2) · CH2Cl2.

Section snippets

Experimental

Na2MoO4 · 2H2O, dimethylsulfoxide and 1,10-phenanthroline were used as purchased from E. Merck. All solvents (methanol, ethanol, isopropanol, dichloromethane, and benzene) were dried by standard methods before use. Stringent precautions were taken to exclude moisture during experimental manipulations. Literature methods were used for the preparation of sodium or potassium salts of N,N-dialkyl dithiocarbamate [18] and O-alkyl dithiocarbonate [19].

Results and discussion

Reactions of dibromodioxobis(dimethylsulfoxide)molybdenum(VI) complexes with sodium/potassium salts of N,N′-dialkyl dithiocarbamates or O-alkyl dithiocarbonates in a 1:1 molar ratio in dichloromethane yield dioxomolybdenum(VI) complexes of the type, MoO2Br(S2CNR2)(OSMe2) or MoO2Br(S2COR)(OSMe2), respectively (see Fig. 3)MoO2Br2(OSMe2)2 + NaS2CNR2  MoO2Br(S2CNR2)(OSMe2) + OSMe2  (Free) + NaBrwhere R = Et, Prn, PriMoO2Br2(OSMe2)2 + NaS2COR  MoO2Br(S2COR)(OSMe2) + OSMe2  (Free) + NaBrwhere R = Et, Prn, Pri.

All of

Concluding comments

We have successfully prepared and characterized the following bromodioxodimethylsulfoxide(N,N′-dialkyldithiocarbamate/O-alkyldithiocarbonate)molybdenum(VI) complexes, MoO2Br(S2CNR2)(OSMe2) (R = Et, Prn, Pri) and MoO2Br(S2COR)(OSMe2) (R = Et, Prn, Pri). The IR, UV–Vis and 1H NMR spectra of all of these dioxomolybdenum(VI) complexes are consistent with the proposal of the following tentative structure.

The molecular structures of MoO2Br2(OSMe2)2 and MoO2Br2(C12H8N2) · CH2Cl2 have been determined. They

Acknowledgements

Two of us (R.K. and R.R.) are grateful to UGC, New Delhi for financial support. M.B. Hursthouse thanks the UK Engineering and Physical Sciences Council for support of the X-ray facilities at Southampton University. J.E.D. wishes to thank the University of Windsor for financial support. We are also thankful to RSIC, CDRI, Lucknow for the spectral analyses.

References (37)

  • R. Colton

    Coord. Chem. Rev.

    (1988)
  • L.S. Villata et al.

    Coord. Chem. Rev.

    (2000)
  • J.M. Tunney et al.
  • N. Manwani et al.

    Inorg. Chim. Acta

    (2004)
  • F.J. Arnaiz et al.

    Inorg. Chim. Acta

    (2003)
  • F.J. Arnaiz et al.

    Polyhedron

    (1994)
  • R.J. Magee et al.

    Inorg. Chim. Acta

    (1971)
  • G.S. Bhat et al.

    Thermochim. Acta

    (1993)
  • F.J. Arnaiz et al.

    Polyhedron

    (2000)
  • T. Shibahara et al.

    Inorg. Chim. Acta

    (1983)
  • N. Manwani et al.

    Inorg. Chim. Acta

    (2003)
  • D. Collison et al.

    Chem. Soc. Rev.

    (1996)
  • R. Hille

    Chem. Rev.

    (1996)
  • E.I. Stiefel

    J. Chem. Soc., Dalton Trans.

    (1997)
  • R. Ratnani et al.
  • A. Thapper et al.

    Inorg. Chem.

    (1999)
  • B.J. Hamstra et al.

    Inorg. Chem.

    (1999)
  • A. Thapper et al.

    Inorg. Chem.

    (1999)
  • Cited by (19)

    • N-hetercycle dimeric molybdenum(V) complexes with strong interactions and their catalytic degradations of methyl orange

      2018, Inorganica Chimica Acta
      Citation Excerpt :

      The structure represents a new discrete dinuclear oxomolybdenum complex modified by SO42− anions [37]. Comparisons of selected bond distances (Å) and angles (◦) for complexes 1 and 5–12 are shown in Table 1 [32,38–44]. The Mo–N distances ranged 2.194(5) to 2.243(5) Å in 1 are significantly stronger than those of 5–12 owing to the particular structure of 1.

    • Nano ranged 1,3-dithia-2-stannacyclopentane(IV) alkyldithiocarbonates: Solid-state NMR, powder X-ray diffraction and thermal decomposition studies

      2015, Journal of Molecular Structure
      Citation Excerpt :

      The IR spectra (4000–400 cm−1) and far-IR spectra (600–50 cm−1) of these derivatives have been recorded as KBr disk and as a NUJOL MULL over CsI disk, respectively. Tentative assignments of the important characteristic bands have been made with the help of earlier publications [25–31] and shown in Table 2. Strong absorption bands appeared in the region 1240–1270 cm−1 and 1125–1180 cm−1 assigned to asymmetrical and symmetrical stretching vibrations of the CO band in the OCS2 group of xanthate moiety, respectively.

    • Heterogenization of a molybdenum Schiff base complex as a magnetic nanocatalyst: An eco-friendly, efficient, selective and recyclable nanocatalyst for the oxidation of alkenes

      2013, Comptes Rendus Chimie
      Citation Excerpt :

      Magnetically recoverable materials have been used in a wide range of catalytic reactions, including oxidations, hydrogenations, photocatalysis, and CC bond formation, as well as in novel applications in asymmetric synthesis, hydration, Knoevenagel condensations, and CO2 cyclo-addition reactions [28–30]. On the other hand, dioxidomolybdenum(VI) complexes are of interest as models for molybdoenzymes [31–33] and used as catalysts for the epoxidation of olefins [34–40]. The objective of this work is to immobilize a molybdenum Schiff base complex onto magnetite nanoparticles with the hydrogen bonding method to obtain a heterogeneous molybdenum magnetic nanocatalyst for the epoxidation of olefins.

    • Difluoridodioxido(1,10-phenanthroline)molybdenum(VI)

      2009, Acta Crystallographica Section E: Structure Reports Online
    • Phenanthroline and its molybdenum complexes

      2020, A Closer Look at Phenanthroline
    View all citing articles on Scopus
    View full text