Elsevier

Inorganica Chimica Acta

Volume 458, 24 March 2017, Pages 77-83
Inorganica Chimica Acta

Research paper
Synthesis, spectroscopic and structural characterization and antibacterial activity of new dimeric and polymeric mercury(II) complexes of phosphonium ylide

https://doi.org/10.1016/j.ica.2016.12.023Get rights and content

Highlights

  • Synthesis and characterization of Hg(II) phosphonium ylide complexes are presented.

  • 1H, 13C and 31P NMR spectroscopies can be used to determinate the coordination mode of the ligand.

  • X-ray analysis demonstrate the dimeric structure of [(Y)HgX2]2 with Cα-coordinated ligand.

  • Antibacterial activity of the ligand and dimeric and polymeric Hg(II) complexes are presented.

Abstract

The new α-keto stabilized phosphonium ylide (p-tolyl)3C(H)C(O)C6H4-m-Br (Y) was synthesized by addition of tri(p-tolyl)phosphine to 2,3′-dibromoacetophenone, followed by treatment with NaOH 10%. The reaction of this ylide with HgX2 (X = Cl, Br and I) and Hg(NO3)2·H2O in equimolar ratio using dry methanol as solvent led to formation of dimeric complexes of type [(Y)HgX2]2 (X = Cl (1), Br (2), I (3)) and polymeric complex of [(Y)Hg(NO3)2]n (4). Characterization of obtained compounds was performed by elemental analysis and IR, 1H, 31P and 13C NMR spectroscopies. Also, single crystal X-ray diffraction analysis revealed the symmetric halide-bridged dimeric structure of complex 2. Considering these results, we have confirmed that the coordination of ylide to metal center occurred through the ylidic carbon atom. In addition, we report the antibacterial activity of these complexes against both the Gram-positive and Gram-negative bacteria, which in all cases the observed antibacterial activities exceed that of Tobramycin, Tetracycline and Chloramphenicol as standard.

Graphical abstract

The present study describes the synthesis, characterization and antibacterial activity of dimeric and polymeric Hg(II) complexes of new phosphonium ylide.

  1. Download : Download high-res image (94KB)
  2. Download : Download full-size image

Introduction

The importance of metalated phosphonium ylides in synthetic chemistry and their application in catalysis has been well proved [1], [2], [3], [4], [5], [6], [7]. The main interest is the fact that they are valuable reagents in organic chemistry, particularly in naturally occurring products with biological and pharmacological properties [8], [9], [10], [11], [12]. Among the considerable properties of phosphonium ylides R3P = C(R′)COR″, the high stability and ambidentate nature of these ligands are very interesting [13]. Transition metal complexes of these ylides have attracted much attention due to their versatile coordination modes varying from C-coordination to O-coordination modes [3], [4], [5], [6], [7]. About 50 years ago, the synthesis of Hg(II) complexes of phosphonium salts was reported by Nesmeyanov et al. [14]. Soon after, Weleski et al. proposed a symmetric halide-bridged structure for the dimeric complexes of Hg(II) halides with phosphonium ylides [15]. Finally, in 1995, presence of such dimeric structures containing phosphonium ylide and HgX2 (X = Cl or I) was confirmed crystallographically by Kalyanasundari et al. [16]. However, those were limited to Hg(II) halide complexes. Recently, for the first time, our group reported the polymeric structure of Hg(II) nitrate complexes bearing phosphonium ylides [17]. In fact, the polymeric structure of these complexes arises from the bridging nature of nitrate anions in seven-coordinate complexes. Chart 1 shows a schematic view of possible bonding modes in phosphonium ylide complexes.

Nowadays, the development of metal complexes with the antibacterial activity has been of great interest due to the important worldwide problems of spreading infectious diseases and microorganism’s resistant against them [18], [19], [20]. For this reason, these compounds are used in many products like soaps, detergents, household cleaners, paints, kitchenware, and school and hospital utensils [21]. A wide range of biological activity including rodenticide, ant tubercular, herbicidal, insecticidal and anthelmintic and plant-growth regulator properties were displayed by ligands and their metal complexes [22], [23], [24], [25], [26]. In the present work, we report the synthesis, characterization and antibacterial activities of Hg(II) complexes of phosphonium ylide.

Section snippets

Physical measurements and material

All reactions were carried out in air. All materials were used in reactions such as 2,3′-dibromoacetophenone provided of Acros company. Also tri(p-tolyl)phosphine and Hg(II) salts were prepared from Aldrich company. 1H, 31P and 13C NMR spectra were recorded in CDCl3 or DMSO-d6 as solvent with Bruker 250 MHz and 90 MHz Jeol at 25 °C. Also, the IR spectra were recorded on Perkin Elmer GX FT-IR Spectrometer. All melting points were measured on SMPI apparatus. Elemental analyses for C, H and N atoms

Synthesis of ligand and complexes

The target Hg(II) complexes were synthesized by a reaction sequence starting from the commercially available tri(p-tolyl)phosphine and 2,3′-dibromoacetophenone. This step led to formation of desired phosphonium salt (S), which is followed by treatment with NaOH 10% and elimination of HBr to obtain phosphonium ylide (Y). Equimolar reaction of this ligand with HgX2 (X = Cl, Br and I) and Hg(NO3)2·H2O gave the final products as dimeric complexes of [(Y)HgX2]2 (X: Cl (1), Br (2) and I (3)) and

Conclusion

The present study describes the synthesis and characterization of dimeric and polymeric Hg(II) complexes of phosphonium ylide. The structure of products was determined successfully by IR, 1H, 13C and 31P NMR spectroscopic techniques and elemental analysis. On the basis of the physico-chemical and spectroscopic data, we propose monodentate C-coordination of phosphonium ylide to the metal, which is further confirmed by the X-ray crystal structure of 2. In this complex, the related ligand was

Acknowledgments

We are grateful to Bu Ali Sina University for financial support and Dr. Zebarjadian for recording the NMR spectra.

References (59)

  • O.I. Kolodiazhnyi

    Tetrahedron

    (1996)
  • M.M. Ebrahim et al.

    Polyhedron

    (2007)
  • Y. Oosawa et al.

    J. Organomet. Chem.

    (1976)
  • M.M. Ebrahim et al.

    Polyhedron

    (2007)
  • N.A. Nesmeyanov et al.

    J. Organomet. Chem.

    (1965)
  • E.T. Weleski et al.

    J. Organomet. Chem.

    (1975)
  • M. Kalyanasundari et al.

    J. Organomet. Chem.

    (1995)
  • S.J. Sabounchei et al.

    J. Organomet. Chem.

    (2007)
  • P. Kamalakannan et al.

    J. Inorg. Biochem.

    (2002)
  • Y.F. Yuan et al.

    Inorg. Chim. Acta

    (2001)
  • M. Eweis et al.

    Int. J. Biol. Macromol.

    (2006)
  • S.J. Sabounchei et al.

    Inorg. Chim. Acta

    (2010)
  • S.J. Sabounchei et al.

    J. Organomet. Chem.

    (2007)
  • S.J. Sabounchei et al.

    Polyhedron

    (2012)
  • J. Vicente et al.

    J. Organomet. Chem.

    (1987)
  • R. Usón et al.

    J. Organomet. Chem.

    (1985)
  • E.C. Spencer et al.

    J. Organomet. Chem.

    (2007)
  • S.J. Sabounchei et al.

    J. Organomet. Chem.

    (2011)
  • M. Tumer et al.

    Spectrochim. Acta A

    (2007)
  • S.J. Sabounchei et al.

    Polyhedron

    (2015)
  • S.J. Sabounchei et al.

    J. Organomet. Chem.

    (2014)
  • S.J. Sabounchei et al.

    C. R. Chim.

    (2013)
  • S.J. Sabounchei et al.

    Polyhedron

    (2013)
  • H.J. Christau

    Chem. Rev.

    (1994)
  • V.V. Grushin

    Chem. Rev.

    (2004)
  • A. Spannenberg et al.

    Organometallics

    (2000)
  • G. Wittig

    Angew. Chem.

    (1980)
  • R. Engle et al.

    Synthesis of Carbon-Phosphorus Bonds

    (1988)
  • B.E. Maryanoff et al.

    Chem. Rev.

    (1989)
  • Cited by (0)

    View full text