Mercury(II) complexes of unsymmetric phosphorus ylides: Synthesis, spectroscopic and antibacterial activity studies

Article abstract of DOI:10.1016/j.molstruc.2013.12.066

The reaction of Ph₂PCH₂PPh₂ (dppm) with 2-bromo-3-nitroacetophenone and 2,2′,4′-trichloroacetophenone in chloroform produce the new phosphonium salts [Ph₂PCH ₂PPh₂CH₂C(O)C_6<

Full text of DOI:10.1016/j.molstruc.2013.12.066

Journal of Molecular Structure 1061 (2014) 90–96
Contents lists available at ScienceDirect
Journal of Molecular Structure
journal homepage: www.elsevier.com/locate/molstruc
Mercury(II) complexes of unsymmetric phosphorus ylides: Synthesis,
spectroscopic and antibacterial activity studies
b
a
c
Seyyed Javad Sabounchei a, , Mohammad Panahimehr , Marjan Hosseinzadeh , Roya Karamian ,
⇑
Mostafa Asadbegy c, Azadeh Masumi c
a Faculty of Chemistry, Bu-Ali Sina University, Hamedan 65174, Iran
b Young Research Club, Gachsaran Branch, Islamic Azad University, Gachsaran, Iran
c Department of Biology, Faculty of Science, Bu-Ali Sina University, Hamedan 65174, Iran
h i g h l i g h t s
ꢀ
ꢀ
ꢀ
Synthesis and characterization of some monouclear Hg(II) complexes of the phosphorus ligands.
IR, 1H and 13C NMR spectroscopy demonstrate P, C-coordination of the ligands to the metal.
All of the compounds displayed antibacterial activity against most of the bacteria tested especially on Gram positive ones.
a r t i c l e i n f o
a b s t r a c t
The reaction of Ph2PCH2PPh2 (dppm) with 2-bromo-3-nitroacetophenone and 2,20,40-trichloroacetophe-
none in chloroform produce the new phosphonium salts [Ph2PCH2PPh2CH2C(O)C6H4NO2]Br (1) and
[Ph2PCH2PPh2CH2C(O)C6H3Cl2]Cl (2). Further, by reaction of the monophosphonium salts of dppm with
the strong base triethylaminethe corresponding bidentate phosphorus ylides, Ph2PCH2PPh2@C(H)C(O)
C6H4NO2 (3) and Ph2PCH2PPh2@C(H)C(O)C6H3Cl2 (4) were obtained. The reaction of these ligands with
mercury(II) halides in dry methanol led to the formation of the mononuclear complexes {HgX2[(Ph2PCH2
PPh2C(H)C(O)C6H4NO2)]} [X = Cl (5), Br (6), I (7)] and {HgX2[(Ph2PCH2PPh2C(H)C(O)C6H3Cl2)]} [X = Cl (8),
Br (9), I (10)]. Characterization of the obtained compounds was performed by elemental analysis, IR, 1H,
31P and 13C NMR. The structure of compound 1 being unequivocally determined by single crystal X-ray
diffraction techniques. The mass spectrum of compound 6 (as an instance) also demonstrates the synthe-
size of these compounds. In all complexes the title ylides are coordinated through the ylidic carbon and
the phosphine atom. These compounds form five membered ring under complexation. The antibacterial
effects of DMSO solutions of the ligands and their metal complexes were evaluated by the disc diffusion
method against six Gram positive and negative bacteria. All compounds represent antibacterial activity
against these bacteria with high levels of inhibitory potency exhibited against the Gram positive species.
Ó 2014 Elsevier B.V. All rights reserved.
Article history:
Received 15 July 2013
Received in revised form 23 November 2013
Accepted 18 December 2013
Available online 2 January 2014
Keywords:
Phosphorus ylide
Mercury(II) halides complexes
Multinuclear NMR study
Antibacterial activity
1. Introduction
attention due to their versatile coordination chemistry and their
application in catalysis [11–15]. The
a-ketostabilized ylides
Phosphorus ylides are important reagents in organic chemistry,
especially in the synthesis of naturally occurring products with
biological and pharmacological activities [1–5]. These ligands are
reactive compounds, which take part in many reactions of value
in the synthesis of organic products [6–9]. The coordination and
derived from bisphosphines, Ph2PCH2PPh2@C(H)C(O)R, Ph2PCH2
CH2PPh2@C(H)C(O)R (R = Me, Ph or OMe) [16] and PhC(O)C(H)
@PPh2CH2CH2PPh2@C(H)C(O)Ph [15] form an important class of
such ligands which can exist in ylidic and enolate forms. These
ligands can therefore engage in different types of bonding as illus-
trated in Chart 1. The PAC, coordinated mode had been previously
observed for Pd(II), Pt(II), Rh(I), Hg(II) [5,7,11,14,15,17–22].
The remarkable change in reactivity arises from a subtle
variation in the molecular electronic structure of the ylide due
to the presence of additional keto stabilization [23]. Much of
the interest in the coordination properties of resonance stabilized
phosphorus ylides stemming from their bond versatility due to
organometallic chemistry of
a-ketostabilized phosphorus ylides
has been investigated and their ambidenticity explained in terms
of a delicate balance between electronic and steric factors [10].
Transition metal complexes of these ligands have attracted much
⇑
Corresponding author. Tel.: +98 8118272072; fax: +98 8118273231.
E-mail address: jsabounchei@yahoo.co.uk (S.J. Sabounchei).
0022-2860/$ - see front matter Ó 2014 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.molstruc.2013.12.066

S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
91
Chart 1. The possible bonding modes of Ph2PCH2PPh2C(H)C(O)R to metal M.
the presence of different functional groups in their molecular
2.2. X-ray crystallography
structure [24,25]. Nowadays, microorganisms resistant to
antimicrobial agents are serious problems worldwide in the fight
against infectious diseases and the development of materials with
the ability to inhibit bacterial growth have been of great interest
in recent years due to their potential use in everyday products
like paints, kitchenware, school and hospital utensils [26]. Li-
gands and their metal complexes display a wide range of biolog-
ical activity including antitubercular, antithroid, antihelmintic,
rodenticidal, insecticidal, herbicidal, and plant-growth regulator
properties [27–31]. Recently the antibacterial potency of many
new synthesized compounds and metal complexes was investi-
gated [32–41]. Although some metal complexes are among the
most widely used antibacterial, but assessment of antibacterial
activity of new metal complexes with ligands system is very nec-
essary. In the present work, we have prepared a series of Hg(II)
complexes with ligands system and investigated their antibacte-
rial activity.
Data collection from suitable crystals of 1was performed on an
Oxford Diffraction single-crystal X-ray diffractometer using mirror
monochromated Mo K
a radiation (0.71073 Å) at 130 K. Gaussian
absorption corrections were carried out using a multifaceted crys-
tal model, using CrysAlisPro [42]. The structure was solved by di-
rect methods and refined by the full-matrix least-squares
method on F2 using the SHELXTL-97 crystallographic package
[43]. All non-hydrogen atoms were refined anisotropically. Hydro-
gen atoms were inserted at calculated positions using a riding
model, with isotropic displacement parameters.
2.3. Antibacterial activity
The potential antibacterial effects of the ligands and Hg(II) com-
plexes were investigated by disc diffusion method against 3 Gram
positive bacteria, namely Bacillus cereus (PTCC 1247), Staphylococ-
cus aureus (Wild) and Bacillus megaterium (PTCC 1017), and 3 Gram
negative bacteria, namely Escherichia coli (Wild), Proteus vulga-
ris(PTCC 1079), and Serratia marcescens (PTCC 1111) [44]. The com-
2. Experimental
2.1. Physical measurements and materials
plexes were dissolved in DMSO to
a
final concentration of
m Milli-
1 mg mLꢁ1 and then sterilized by filtration using 0.45
l
All reactions were carried out under an atmosphere of dry
nitrogen. Methanol was distilled over magnesium powder and
diethyl ether (Et2O) over a mixture of sodium and benzophenone
just before use. All other solvents were reagent grade and used
without further purifications. Melting points were measured on
a SMP3 apparatus. IR spectra were recorded on a Shimadzu
435-U-04 spectrophotometer from KBr pellets. 1H, 13C and 31P
NMR spectra were recorded on 300 MHz Bruker and 90 MHz Jeol
spectrometer in DMSO-d6 or CDCl3 as solvent at 25 °C. Chemical
shifts (ppm) are reported according to internal TMS and external
85% phosphoric acid. Coupling constants are given in Hz.
Elemental analysis for C, H and N atoms were performed using
a Perkin–Elmer 2400 series analyzer.
pore. All tests were carried using 10 mL of suspension containing
1.5 ꢂ 108 bacteria/mL and spread on nutrient agar medium. Nega-
tive controls were prepared by using DMSO. Gentamicin, Penicillin,
Neomycinand, Nitrofurantoin were used as positive reference
standards. The diameters of inhibition zones generated by the
complexes were measured.
2.3.1. Statistical analysis
All data, for both antibacterial tests, are the average of triplicate
analyses. Analysis of variance was performed by Excel and SPSS
procedures. Statistical analysis was performed using student’s
t-test, and p value < 0.05 was regarded as significant.

92
S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
2.4. Sample preparation
through a short plug of Celite. Addition of excess methanol to the
concentrated filtrate caused the precipitation of the products as
solids.
2.4.1. Synthesis of monophosphonium salts
2.4.1.1. Synthesis of [Ph2PCH2PPh2CH2C(O)C6H3Cl2]Cl(1). Bis(diphen-
ylphosphino)methane (dppm) (0.50 g, 1.30 mmol) was dissolved in
8 ml of chloroform and then a solution of 2,20,40-trichloroacetoph-
enone (0.29 g, 1.30 mmol) in the same solvent (5 ml) was added
dropwise to the above solution. The resulting solution was stirred
for 10 h at room temperature and then was concentrated under re-
duced pressure to about 2 ml. Diethyl ether (20 ml) was added and
the white solid formed was filtered off, and dried under reduced
pressure. Yield: 0.60 g (77%); m.p. 185–187 °C. Anal. Calc. for
2.4.3.1. Data for {HgCl2[(Ph2PCH2PPh2C(H)C(O)C6H3Cl2)]}(5). Yield
0.18 g, 54%. M.p. 215–217 °C. Anal. Calc. for C33H26Cl4HgOP2: C,
47.03; H, 3.11. Found: C, 46.84; H, 3.13%. IR (KBr, cmꢁ1): 1583
(C@O), 1436, 1324, 1183, 1109, 774, 736, 688. 1H NMR (DMSO-
d6): dH = 3.42 (br, 2H, CH2); 4.74 (br, 1H, CH); 7.43–7.96 (m, 23H,
Ph). 31P NMR (DMSO-d6): dp = 9.67 (br, PPh2); 22.86 (d, PCH,
2sP-P = 48.59). 13C NMR (DMSO-d6): dc = 22.56 (br, CH2); 32.43
(br, CH); 117.62–136.61 (Ph); 190.41 (s, CO).
C
33H27Cl3OP2 (%): C, 65.34; H, 4.48. Found: C, 65.55; H, 4.54.
Selected IR absorption in KBr (cmꢁ1): 1683 (
m
C@O). 1H NMR (CDCl3).
2
dH: 4.29 (d, 2H, PCH2P, JPH = 14.4); 6.07 (d, 2H, PCH2CO,
2JPH = 12.6); 7.20–8.45 (m, 23H, Ph). 31P NMR (CDCl3) dP: ꢁ29.03
2.4.3.2. Data for {HgBr2[(Ph2PCH2PPh2C(H)C(O)C6H3Cl2)]} (6). Yield:
0.22 g, 59%. M.p. 220–222 °C. Anal. Calc. for C33H26Br2Cl2HgOP2:
C, 42.53; H, 2.81. Found: C, 42.25; H, 2.85%. IR (KBr, cmꢁ1): 1587
(C@O), 1438, 1178, 1121, 784, 742, 692. 1H NMR (DMSO-d6):
dH = 3.37 (br, 2H, CH2); 4.7 (br, 1H, CH); 7.48–8.01 (m, 23H, Ph).
31P NMR (DMSO-d6): dp = 1.348 (br, PPh2); 20.43 (d, PCH,
2JP-P = 16.28). 13C NMR (DMSO-d6): dc = 22.71 (br, CH2); 32.06 (br,
CH); 118.30–136.75 (Ph); 190.59 (s, CO). MS m/z(%): 932(M),
757, 571, 547, 417, 384, 360, 261, 201, 187, 77, 51.
(d, PPh2, JPP = 64.76); 20.34 (d, PCH2CO, JPP = 63.56). 13C NMR
2
2
1
(CDCl3) dC: 21.18 (br, PCH2P); 33.96 (d, PCH2, JPC = 58.01);
126.63–139.79 (Ph); 184.90 (s, CO).
2.4.1.2. Synthesis of [Ph2PCH2PPh2CH2C(O)C6H4NO2]Br (2). A solution
of dppm (0.50 g, 1.30 mmol) and 2-bromo-3-nitroacetophenone
(0.31 g, 1.30 mmol) in chloroform was stirred at room temperature
for 10 h. The orange solid formed was filtered off, and dried under
reduced pressure. Yield: 0.70 g (87%); m.p. 172–174 °C. Anal. Calc.
for C33H28BrNO3P2 (%): C, 63.15; H, 4.50; N, 2.23. Found: C, 62.94;
2.4.3.3. Data for {HgI2[(Ph2PCH2PPh2C(H)C(O)C6H3Cl2)]}(7). Yield
0.22 g, 55%. M.p. 228–230 °C. Anal. Calc. for C33H26Cl2HgI2OP2: C,
38.60; H, 2.55. Found: C, 38.78; H, 2.53%. IR (KBr, cmꢁ1): 1584
(C@O), 1437, 1321, 1186, 1103, 792, 740, 688. 1H NMR (DMSO-
d6): dH = 3.31 (br, 2H, CH2); 4.61 (br, 1H, CH); 7.44–8.13 (m, 23H,
Ph). 31P NMR (DMSO-d6): dp = ꢁ7.12 (br, PPh2); 21.07 (d, PCH,
2JP-P = 35.79). 13C NMR (DMSO-d6): dc = 22.75 (br, CH2); 30.12 (br,
CH); 118.16–135.62 (Ph); 191.42 (s, CO).
H, 4.48; N, 2.29. Selected IR absorption in KBr (cmꢁ1): 1682 (
mC@O).
2
1H NMR (CDCl3) dH: 4.31 (d, 2H, PCH2P, JPH = 14.35); 5.83 (d, 2H,
2
PCH2CO, JPH = 12.8); 7.25–7.82 (m, 24H, Ph). 31P NMR (CDCl3) dP:
2
2
ꢁ29.64 (d, PPh2, JPP = 64.51); 20.68 (d, PCH2CO, JPP = 64.70). 13C
2
NMR (CDCl3) dC: 20.89 (br, PCH2P); 36.05 (d, PCH2, JPC = 60.53);
115.41–147.53 (Ph); 190.31 (s, CO).
2.4.2. Synthesis of bidentate phosphorus ylides
2.4.2.1. Synthesis of Ph2PCH2PPh2@C(H)C(O)C6H3Cl2 (3). The mono-
phosphonium salt (1) (0.30 g, 0.50 mmol) was treated with triethyl
amine (0.50 mL) in toluene (15 mL). The triethylamine hydrobro-
mide thus obtained was filtered off. Concentration of the toluene
layer to about 2 mL and subsequent addition of diethyl ether
(20 mL) resulted in the precipitation of the desired ligand as white
solid. Yield: 0.17 g (61%); m.p. 163–165 °C. Anal. Calc. for C33H26
Cl2OP2(%): C, 69.46; H, 4.59. Found: C, 69.81; H, 4.57. Selected IR
2.4.3.4. Data for {HgCl2[(Ph2PCH2PPh2C(H)C(O)C6H4NO2)]}(8). Yield
0.22 g, 68%. M.p. 180–182 °C. Anal. Calc. for C33H27Cl2HgNO3P2: C,
48.34; H, 3.32; N, 1.7. Found: C, 48.41; H, 3.36; N, 1.78%. IR (KBr,
cmꢁ1): 1581 (C@O), 1437, 1345, 1153, 1109, 772, 741, 690. 1H
2
NMR (DMSO-d6): dH = 4.69 (t, 2H, CH2, JPH = 12.9); 5.32 (d, 1H,
2
CH, JPH = 13.08); 7.46–8.68 (m, 24H, Ph). 31P NMR (DMSO-d6):
2
dp = 3.07 (br, PPh2); 23.39 (d, PCH, JPP = 40.10). 13C NMR (DMSO-
absorption in KBr (cmꢁ1): 1583 (
m
C@O). 1H NMR (CDCl3) dH: 3.68
d6): dc = 21.35 (br, CH2); 33.14 (br, CH); 123.16–146.12 (Ph);
193.41 (s, CO).
2
(d, 2H, CH2, JPH = 14.25); 4.27 (br, 1H, CH); 7.24–7.82 (m, 23H,
Ph). 31P NMR (CDCl3) dP: ꢁ29.74 (d, PPh2, JPP = 65.99); 10.31 (d,
2
PCH, JPP = 67.28). 13C NMR (CDCl3) dC: 23.20 (br, PCH2P); 49.54
2
1
(d, CH, JPC = 114.15); 115.9–141.84 (Ph); 180.25 (s, CO).
2.4.3.5. Data for {HgBr2[(Ph2PCH2PPh2C(H)C(O)C6H4NO2)]}(9). Yield
0.25 g, 70%. M.p. 189–191 °C. Anal. Calc. for C33H27Br2HgNO3P2:
C, 43.66; H, 3.00; N, 1.54. Found: C, 43.51; H, 3.03; N, 1.68%. IR
(KBr, cmꢁ1): 1580 (C@O), 1486, 1342, 1151, 1110, 791, 739, 688.
2.4.2.2. Synthesis of Ph2PCH2PPh2@C(H)C(O)C6H4NO2 (4). This phos-
phorus ylide was obtained using the same procedure as adopted
for the preparation of 3 using monophosphonium salt (2) (0.31 g,
0.50 mmol). Yield: 0.20 g (76%); m.p. 155–157 °C. Anal. Calc. for
2
1H NMR (DMSO-d6): dH = 4.68 (t, 2H, CH2, JPH = 12.24); 5.40 (d,
1
1H, CH, JPH = 14.04); 7.44–8.64 (m, 24H, Ph). 31P NMR (DMSO-
2
d6): dp = ꢁ5.82 (br, PPh2); 24.95 (d, PCH, JPP = 38.62). 13C NMR
C
33H27NO3P2 (%): C, 72.37; H, 4.97; N, 2.56. Found: C, 72.34; H,
4.99; N, 2.63. Selected IR absorption in KBr (cmꢁ1): 1584 (
mC@O).
(DMSO-d6): dc = 21.87 (br, CH2); 34.38 (br, CH); 123.9–147.33
1H NMR (CDCl3) dH: 3.66 (d, 2H, CH2, JPH = 14.15); 4.23 (bd, 1H,
2
(Ph); 193.07 (s, CO).
CH, JPH = 7.70); 7.22–8.58 (m, 24H, Ph). 31P NMR (CDCl3) dP:
2
ꢁ30.19 (d, PPh2, JPP = 63.13); 11.79 (d, PCH, JPP = 64.94). 13C
2
2
1
NMR (CDCl3) dC: 21.87 (br, CH2); 51.12 (d, CH, JPC = 105.28);
2.4.3.6. Data for {HgI2[(Ph2PCH2PPh2C(H)C(O)C6H4NO2)]}(10). Yield
0.24 g, 61%. M.p. 203–205 °C. Anal. Calc. for C33H27I2HgNO3P2: C,
39.48; H, 2.71; N, 1.39. Found: C, 39.47; H, 2.74; N, 1.36%. IR
(KBr, cmꢁ1): 1587 (C@O), 1436, 1346, 1173, 1103, 776, 739, 687.
121.12–149.62 (Ph); 184.11 (s, CO).
2.4.3. Preparation of the complexes
2
General procedure: To a solution of HgX2 (0.40 mmol) in meth-
anol (8 mL), a solution of 3 or 4 (0.40 mmol) in the same solvent
(8 mL) was added dropwise at 0 °C and the reaction allowed to pro-
ceed under stirring for 2 h. The resulting solid, admixed with gray
material was treated with dichloromethane (25 mL) and filtered
1H NMR (DMSO-d6): dH = 4.72 (t, 2H, CH2, JPH = 12.99); 5.40 (d,
1
1H, CH, JPH = 8.78); 7.44–8.64 (m, 24H, Ph). 31P NMR (DMSO-d6):
2
dp = ꢁ9.37 (br, PPh2); 24.44 (d, PCH, JPP = 43.62). 13C NMR
(DMSO-d6): dc = 22.28 (br, CH2); 33.47 (br, CH); 122.58–141.64
(Ph); 192.53 (s, CO).

S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
93
O
O
O
Ph2
P
Ph2
P
Br
R
R
Et3N
R
Chloroform
RT, 24h
X
+
PPh2
PPh2
PPh2
(3): R =3-nitrophenyl
(4): R =2,4-dichlorophenyl
(1): R =3-nitrophenyl, X=Br
(2): R =2,4-dichlorophenyl, X=Cl
PPh2
Scheme 1. Synthetic route for the preparation of ligands 3–4.
PPh2
CH3OH
Ph2PCH2PPh2=CHC(O)R
HgX2
+
Ph2P
CH
C
O
R
under N2, 2h
Hg
x
x
(8): R = 2,4-dichlorophenyl, X = Cl
(9): R = 2,4-dichlorophenyl, X = Br
(10): R = 2,4-dichlorophenyl, X = I
(5): R = 3-nitrophenyl, X = Cl
(6): R = 3-nitrophenyl, X = Br
(7): R = 3-nitrophenyl, X = I
Scheme 2. Synthetic route for the preparation of complexes 5–10.
three signals centered at 3.68 (d) and 4.27 (br) of relative inten-
sity 2:1 attributed to the PCH2P and P@CH, respectively [20].
The 31P NMR spectrum for complexes exhibit the presence of
the PCH group as a doublet around 21 and 24 ppm for complexes
5–7 and 8–10, respectively. These chemical shifts are lower field
to that observed for the corresponding free ylides, indicating that
coordination of the ylides have occurred. The 31P NMR spectrum
3. Results and discussion
3.1. Synthesis
The ligands were synthesized by treating bis(diphenylphos-
phino)methane with 2-bromo-3-nitroacetophenone and 2,20,40-tri-
chloroacetophenone and removal of the proton from the
phosphonium salts by triethylamine (Scheme 1) [11]. Reaction of
HgX2 with the ylides 3 and 4 in a 1:1 stoichiometry afforded the
P, C-coordinated complexes with a chelating structure (Scheme 2).
All complexes soluble in dichloromethane and all were obtained in
good yields.
2
of 5 exhibits a doublet at 22.86 with a coupling constant JPP of
48.59 Hz and a broad signal at 9.67 ppm, attributable to PCH2
and PPh2 groups, respectively. The 1H NMR spectrum exhibits a
Table 1
Crystal data and refinement details for 1.
3.2. IR spectra
Compound
1
The IR data confirm the complete formation of the carbonylic
ylides with the disappearance of the CO band at 1683 and
1682 cmꢁ1 in phosphonium salts 1 and 2 and the presence of a
new strong CO band at 1583 and 1587 cmꢁ1 in resulting carbonyl
stabilized ylides 3 and 4, respectively [18,45]. The coordination
of the ylide through carbon causes a significant increase in the
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C34 H28 Cl6 O P2
723.97
298(2)
0.71073
Monoclinic
C2/c
30.1043(11)
16.1198(4)
16.1617(6)
90
117.564(5)
90
m
(C@O) frequency [46]. Thus infrared absorption bands observed
b (Å)
c (Å)
around 1590 cmꢁ1 for all complexes indicate coordination of the
ylides through ylidic carbon atom [47].
a
(°)
b (°)
c
(°)
Z
8
3.3. NMR spectra
Absorption coefficient (mmꢁ1
)
0.180
h Range for data collection (°)
Index ranges
2.14–29.18
ꢁ18 6 h 6 17
ꢁ21 6 k 6 25
ꢁ15 6 l 6 15
19449
7552 [R(int) = 0.1159]
Numerical
0.945 and 0.940
Full-matrix least-squares on F2
1.136
The 31P NMR spectrum of 1 exhibits two doublets at 20.34 and
ꢁ29.03 ppm that indicate the PCH2CO and PPh2 groups, respec-
tively. The 1H NMR spectrum exhibits a doublet at 6.07 ppm, with
a coupling constant 2JPH of 12.6 Hz, due to a CH2 group bonded to a
phosphonium moiety [48]. The 31P NMR spectrum of 3 exhibits
two doublets at 10.31 ppm and ꢁ29.74 ppm that indicate the
phosphonium phosphorous and free phosphine atoms, respec-
tively. The phosphonium atom of this compound shows upfield
shifts compared to that of parent phosphonium salt (1), suggesting
some increasing of electron density in the PAC bond [45]. The 1H
NMR spectrum of 3 shows, in addition to the aromatic resonances,
Reflections collected
Independent reflections
Absorption correction
Max. and min. transmission
Refinement method
Goodness-of-fit on F2
Final R indices [I > 2
r
(I)]
R1 = 0.1011, wR2 = 0.2111
R1 = 0.1864, wR2 = 0.2471
0.386 and ꢁ0.279
R indices (all data)
Largest diff. peak and hole (e Åꢁ3
)

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S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
3.4. X-ray crystallography study
Colorless crystals of 1 were obtained from a chloroform solution
by slow evaporation of the solvent. Table 1 provides the crystallo-
graphic results and refinement information for compound 1. Ther-
mal ellipsoid plot shows that in this molecule the geometry around
the P atom is nearly tetrahedral, and the O atom is oriented cis to
the P(2) atom. The C(26)AP(2) (1.806(2)) and C(27)AO(1)
(1.218(3)) bond lengths are comparable with the (P+AC (sp3)
(1.800) and (CAO) (1.210) normal values, respectively.
C(26)AP(2) bond length is shorter and C(27)AO(1) bond length is
longer than PAC and CO bond lengths in phosphorus ylides
[50,51]. This bond distances suggest no electron delocalization in
this molecule. For complex 1, about the slightly high R-factors, it
is to be noted that some atoms have a high thermal parameter
due to data collection in room temperature. We tried refining these
atoms in two positions with reduced occupancy but while this
model converged satisfactorily, there was no decrease in R value
and therefore we consider that our original refinement is the best
that can be achieved and should be reported. On the other hand,
this compound slowly decomposed even under perfluoro-poly-
ether oil and the crystal used for data collection had some damage.
Therefore, the raw data for this compound is slightly poor
(R1 = 0.1011). The molecular structure of complex 1 is shown in
Fig. 1 and relevant bond lengths and angles are given in Table 2.
Fig. 1. Crystal structure of 1.
Table 2
3.5. Antibacterial activity
Selected bond lengths (Å) and bond angles (°) for 1.
C(13)AP(2)
C(26)AC(27)
C(27)AO(1)
C(26)AP(2)
C(13)AP(2)AC(14)
C(13)AP(2)AC(20)
C(13)AP(2)AC(26)
C(14)AP(2)-C(20)
C(14)AP(2)AC(26)
C(20)AP(2)AC(26)
1.796(2)
1.522(3)
1.218(3)
1.806(2)
109.9(1)
112.0(1)
109.95(9)
106.9(1)
108.83(9)
109.17(9)
Results from the antibacterial assessment of the ligands and
metal complexes are presented in Tables 3 and 4, respectively.
Positive and negative controls are shown in Table 5. All of the
compounds displayed antibacterial activity against most of the
bacteria tested especially on Gram positive ones. However,
Staphylococcus saprophyticus (+) was the most resistant bacterium.
Also free ligands and Hg ions, separately displayed antibacterial
activity against these bacteria. According to our results from
comparison of the effect of ligands, Hg ions and also Hg complexes
on growth inhibition of bacteria, the complexes exhibit higher
antibacterial activity than the free ligands. However, Hg ions exhi-
bit a higher antibacterial activity than its complexes (Tables 3 and
4). Generally, antibacterial activities of the compounds are attrib-
uted mainly to their major components. However, today it is well
known that the synergistic or antagonistic effect of one compound
present in a minor percentage of a mixture has to be considered
[52,53]. It is known that certain metal ions or their complex pene-
trate into bacteria and inactivate their enzymes, or some metal
ions can generate hydrogen peroxide, thus killing bacteria. We
can consider that different coordination of the ligands to metal
complex may facilitate the ability of a metal complex to cross
the lipid layer of the bacterial cell membrane and in this way
may be affected the mechanisms of growth and development of
broad signal at 4.74 ppm, related to a CH group bonded to mer-
cury atom that be shifted downfield with respect to the parent
ylide 3 [18]. The 31P NMR spectrum of 8 shows a doublet at
2
23.39 ppm with a coupling constant JPP of 40.10 Hz and a broad
signal at 3.07 ppm, which are assigned to the PC(H) and PPh2
groups, respectively. The 1H NMR spectrum shows a doublet at
5.32 ppm attributable to the ylidic proton with a coupling con-
2
stant JPH of 13.08 Hz [49]. The 13C NMR shifts of the CO group
in the complexes are about 190–193 ppm, relative to 180.25
and 184.11 ppm noted for the same carbon in the parent ylides,
indicating much lower shielding of the carbon of the CO group
in these complexes.
Table 3
Antibacterial activity of ligands.
Ligands
Inhibition zone (mm)
Concentration (mg mlꢁ1
)
S. marcescens (ꢁ)
C. amalonaticus (ꢁ)
na
na
na
E. aerogenes (ꢁ)
na
na
na
B. megaterium (+)
S. aureus (+)
S. saprophyticus (+)
1
0.1
0.01
11.5 0.26a
10.5 0.34b
9
9
8
0.33a
0.17a
0.00b
12.5 0.28a
10 0.28b
na
na
na
na
3
4
9
0.21c
0.28a
1
0.1
0.01
9
na
na
na
11 0.28a
8
8
0.46a
0.54a
9
8
8
0.25a
0.34b
0.00b
na
na
na
8.5 0.28a
8.5 0.21a
10.5 0.41ab
9.5 0.28b
na
Experiment was performed in triplicate and expressed as mean SD. Values with different superscripts within each column (for any bacteria in different concentrations) are
significantly different (P < 0.05).
na: No active.

S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
95
Table 4
Antibacterial activity of metal complexes.
Complex
Inhibition zone (mm)
Concentration (mg mlꢁ1
)
S. marcescens (ꢁ)
C. amalonaticus (ꢁ)
E. aerogenes (ꢁ)
9
8
na
B. megaterium (+)
S. aureus (+)
S. saprophyticus (+)
1
0.1
0.01
9.5 0.28a
11 11a
0.28a
16b
13 0.33a
15.5 0.28a
10 0.28
na
na
5
9
9
0.18a
0.46a
8
33b
9
8
0.14b
0.21c
11 0.28b
na
9
0.25c
1
0.1
0.01
10 0.28a
9.5 0.56a
8
12 0.14a
9.5 0.18b
8
11 0.18a
8
8
15 0.22a
17 0.28a
11 0.28b
8
10 0.25
na
na
6
0.00b
0.34b
9
0.21b
0.10b
0.00c
7.5 0.28c
0.11c
1
0.1
0.01
10 0.28a
0.33b
7.5 0.17c
12 0.28
na
na
12 0.36a
9
na
15.5 0.28a
9
8
17 0.12a
10 0.21b
8.5 0.24c
9.5 0.28
na
na
7
9
0.00b
0.22b
14c
1
0.1
0.01
9
8
8
12a
11.5 0.28
na
na
12 0.45a
8
8
14 0.22a
9
na
20 0.24a
13 0.16b
na
10 0.14
na
na
8
0.28b
34b
0.54b
13b
0.28b
1
0.1
0.01
9
8
8
0.18a
0.21b
0.43b
9
8
na
0.28a
16b
10.5 0.28a
8
8
12 0.28a
8
na
16 0.23a
8
na
na
na
na
9
0.44b
0.17b
0.43b
0.12b
1
0.1
0.01
9
8
8
0.28a
0.45b
0.34b
9.5 0.28
na
na
10 0.11a
0.13b
8.5 0.28b
12 0.28a
9
na
15 0.11a
11 0.28b
na
na
na
na
10
9
0.23b
Experiment was performed in triplicate and expressed as mean SD. Values with different superscripts within each column (for any bacteria in different concentrations) are
significantly different (P < 0.05).
na: No active.
Table 5
Antibacterial activity of antibiotics as positive controls and DMSO solve as negative control.
Microorganism
Inhibition zone
Positive controls
Penicillin
Negative controls
DMSO
Gentamicin
Neomycin
Nitrofurantoin
B. megaterium (+)
S. aureus (+)
S. saprophyticus (+)
S. marcescens (ꢁ)
E. aerogenes (ꢁ)
C. amalonaticus (ꢁ)
na
20 0.14
17 0.18
15 0.16
16.5 0.22
16 0.10
12 0.33
20 0.28
14 0.33
13.5 0.14
18 0.55
14 0.34
11.5 0.18
15 0.28
20 0.33
12 0.25
9.5 0.22
12.5 0.18
15 0.54
na
na
na
na
na
na
10.5 0.21
16 0.24
na
na
na
Experiment was performed in triplicate and expressed as mean SD.
na: No active.
bacteria [54,55]. The antibacterial activity can also be influenced
by the slow release of the ligands inside the bacterial cell. The anti-
bacterial activity of the samples in comparison to some reference
antibiotics indicates that the inhibitory potency of the tested li-
gands and chiefly metal complexes was found to be remarkable.
Although most of the bacteria tested are resistant to Penicillin,
the inhibitory effects of all complexes on resistant species were
higher than the mentioned antibiotic. The above results indicate
that the studied complexes may be used in the treatment of dis-
eases caused by the bacteria tested. Further studies are needed
to evaluate the in vivo potential of these new compounds in animal
models.
which might be helpful in preventing the progress of various infec-
tions and can be used as alternative systems for medicines. How-
ever, possible side deleterious effects of these compounds on
human health should be more investigated. Future research should
envision studies on modification of these complexes to increase
their antibacterial activity.
Acknowledgements
We are grateful to the Bu-Ali Sina University for a grant and
Mr. Zebarjadian for recording the NMR spectra.
4. Conclusions
Appendix A. Supplementary material
The present study describes the synthesis and characterization
of a series of chelate mercury(II) complexes derived from mercuric
halides and new mixed phosphine–phosphonium ylides. On the
basis of the physicochemical and spectroscopic data we propose
that ligands herein exhibit bidentate P, C-coordination to the metal
centre. Metal based drug represents a novel group of antimicrobial
agents with potential application for the control of bacterial and
fungal infections. Results from present study clearly demonstrated
that the Hg(II) complexes exhibit acceptable antibacterial activity,
CCDC 881012 contains the supplementary crystallographic data
for the compound 1. These data can be obtained free of charge
via http://www.ccdc.cam.ac.uk/conts/retrieving.html or from the
Cambridge Crystallographic Data Center, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336 033; or E-mail: depos-
it@ccdc.cam.ac.uk. Supplementary data associated with this article
can be found, in the online version, at http://dx.doi.org/10.1016/
j.molstruc.2013.12.066.

96
S.J. Sabounchei et al. / Journal of Molecular Structure 1061 (2014) 90–96
[29] Y.M. Zhang, T.B. Wei, X.C. Wang, S.Y. Yang, Indian J. Chem. Sect. B 37 (1998)
References
604–606.
[30] W.Q. Zhou, B.L. Li, L.M. Zhu, J.G. Ding, Z. Yong, L. Lu, X.J. Yang, J. Mol. Struct. 690
(2004) 145–150.
[31] M. Eweis, S.S. Elkholy, M.Z. Elsabee, Int. J. Biol. Macromol. 38 (2006) 1–8.
[32] B.S. Creaven, D.A. Egan, K. Kavanagh, M. McCann, A. Noble, B. Thati, M. Walsh,
Inorg. Chim. Acta 359 (12) (2006) 3976–3984.
[33] T. Rosu, E. Pahontu, S. Pasculescu, R. Georgescu, N. Stanica, A. Curaj, A. Popescu,
M. Leabu, Eur. J. Med. Chem. 45 (2010) 1627–1634.
[34] N.V. Kulkarni, G.S. Hegde, G.S. Kurdekar, S. Budagumpi, M.P. Sathisha, V.K.
Revankar, Spectrosc. Lett. 43 (2010) 235–246.
[35] M.C. Rodriguez-Arguelles, E.C. Lopez-Silva, J. Sanmartin, P. Pelagatti, F. Zani, J.
Inorg. Biochem. 99 (2005) 2231–2239.
[36] S.J. Sabounchei, F. Akhlaghi Bagherjeri, C. Boskovic, R.W. Gable, R. Karamian, M.
Asadbegy, J. Mol. Struct. 1043 (2013) 265–270.
[37] S.J. Sabounchei, F. Akhlaghi Bagherjeri, C. Boskovic, R.W. Gable, R. Karamian, M.
Asadbegy, Polyhedron 53 (2013) 1–7.
[38] S.J. Sabounchei, M. Ahmadi, Z. Nasri, E. Shams, S. Salehzadeh, Y. Gholiee, R.
Karamian, M. Asadbegy, S. Samiee, C. R. Chimie. 16 (2013) 159–175.
[39] S.J. Sabounchei, F. Akhlaghi, J. Chem. Soc. Dalton Trans. 42 (2013) 2520–2529.
[40] J. Jeeva, T. Ramachandramoorthy, Res. J. Pharmaceutical Sci. 2 (2013) 1–6.
[41] K. Dakshayani, Y. Lingappa, M. Santhosh, R. Sayaji, J. Chem. Pharm. Res. 3 (6)
(2011) 506–513.
[42] P.R.O. CrysAlis, Agilent Technologies, Yarnton, Oxfordshire, England, 2011.
[43] O.V. Dolomanov, L.J. Bourhis, R.J. Gildea, J.A.K. Howard, H. Puschmann, J. Appl.
Cryst. 42 (2009) 339.
[44] A.W. Bauer, M.M. Kirby, J.C. Sherris, M. Truck, Am. J. Clin. Pathol. 45 (1966)
493–496.
[45] J. Vicente, M.T. Chicote, M.C. Lagunas, P.G. Jones, J. Chem. Soc. Dalton Trans.
(1991) 2579–2583.
[46] M. Kalyanasundari, K. Panchanatheswaran, W.T. Robinson, H. Wen, J.
Organomet. Chem. 491 (1995) 103–109.
[47] S.J. Sabounchei, S. Samiee, S. Salehzadeh, Z. Bolboli, Inorg. Chim. Acta 363
(2010) 3654–3661.
[48] R. Navarro, E.P. Urriolabeitia, J. Chem. Soc. Dalton Trans. (1999) 4111–4122.
[49] S.J. Sabounchei, S. Samiee, S. Salehzadeh, Z. Bolboli, J. Organomet. Chem. 695
(2010) 1441–1450.
[50] S.J. Sabounchei, H. Nemattalab, H.R. Khavasi, Anal. Sci. : X-Ray Struct. Anal.
Online 26 (2010) 35–36.
[1] G. Wittig, Angew. Chem. 92 (1980) 671–675.
[2] R. Engle, J.I. Cohen, Synthesis of Carbon–Phosphorus Bonds, second ed., CRC
Press, Boca Raton, 1988.
[3] B.E. Maryanoff, A.B. Reitz, Chem. Rev. 89 (1989) 863–927.
[4] J.I.G. Cadogan, Organophosphorus Reagent in Organic Synthesis, Academic
Press, New York, 1979. p. 155.
[5] D. Saravanabharathi, T.S. Venkatakrishnan, M. Nethaji, S.S. Krishnamurthy,
Proc. Ind. Acad. Sci. (Chem. Sci.) 115 (2003) 741–749.
[6] Y. Shen, Acc. Chem. Res. 31 (1998) 584–592.
[7] L.R. Falvello, S. Fernandez, R. Navarro, E.P. Urriolabeitia, Inorg. Chem. 39 (2000)
2957–2960.
[8] O.I. Kolodiazhnyi, Russ. Chem. Rev. 66 (1997) 225–254.
[9] C. Puke, G. Erker, N.C. Aust, E.U. Wurthweine, R. Frohich, J. Am. Chem. Soc. 120
(1998) 4863–4864.
[10] J.V. Effendy, F. Hanna, D. Marchetti, C. Martini, R. Pettinari, B.W. Pettinari, A.H.
Skelton, Inorg. Chim. Acta 357 (2004) 1523–1537.
[11] V.V. Grushin, Chem. Rev. 104 (2004) 1629–1662.
[12] M.M. Ebrahim, A. Neels, H. Stoeckli-Evans, K. Panchanatheswaran, Polyhedron
26 (2007) 1277–1284.
[13] Y. Oosawa, H. Urabe, T. Saito, Y. Sasaki, J. Organomet. Chem. 122 (1976) 113–121.
[14] A. Spannenberg, W. Baumann, U. Rosenthal, Organometallics 19 (2000) 3991–
3995.
[15] M.M. Ebrahim, H. Stoeckli-Evans, K. Panchanatheswaran, Polyhedron 26
(2007) 3491–3495.
[16] H.J. Christau, Chem. Rev. 94 (1994) 1299–1313.
[17] O.I. Kolodiazhnyi, Tetrahedron 52 (1996) 1855–1929.
[18] S.M. Sbovata, A. Tassan, G. Facchin, Inorg. Chim. Acta 361 (2008) 3177–3183.
[19] R. Uson, J. Fornies, R. Navarro, A.M. Ortega, J. Organomet. Chem. 334 (1987)
389–397.
[20] L.R. Falvello, M.E. Margalejo, R. Navarro, E.P. Urriolabeitia, Inorg. Chim. Acta
347 (2003) 75–85.
[21] H. Takahashi, Y. Oosawa, A. Kobayashi, T. Saito, Y. Sasaki, Chem. Lett. (1976)
15–16.
[22] M.M. Ebrahima, K. Panchanatheswaran, A. Neels, H. Evans, J. Organomet.
Chem. 694 (2009) 643–648.
[23] G. Wagner, T.B. Pakhomova, N.A. Bokach, J.J.R. Frausto da Silva, J. Vicente, A.J.L.
Pombeiro, V.Y. Kukushkin, Inorg. Chem. 40 (2001) 1683–1689.
[24] G.M. Sheldrick, Acta Cryst. A64 (2008) 112–122.
[25] Stoe & Cie, X-STEP32. Stoe & Cie GmbH, Darmstadt, Germany, 2005.
[26] A.T. Kabbani, H.H. Hammud, A.M. Ghannoum, Chem. Pharm. Bull. 55 (2007)
446–450.
[27] Y.F. Yuan, J.T. Wang, M.C. Gimeno, A. Laguna, P.G. Jones, Inorg. Chim. Acta 324
(2001) 309–317.
[28] Y.M. Zhang, T.B. Wei, L. Xian, L.M. Gao, Sulfur Silicon Relat. Elem. 179 (2004)
2007–2013.
[51] S.J. Sabounchei, M. Panahimehr, M. Ahmadi, Z. Nasri, H.R. Khavasi, J.
Organomet. Chem. 723 (2013) 207–213.
[52] J.E. Gray, P.R. Norton, R. Alnouno, C.L. Marolda, M.A. Valvano, K. Griffiths,
Biomaterials 24 (2003) 2759–2765.
[53] S.A. Burt, Food Microbiol. 94 (2004) 223–253.
[54] N. Fahmi, I.J. Gupta, R.V. Singh, Sulfur Silicon Relat. Elem. 132 (1998) 1–7.
[55] M. Tumer, D. Ekinci, F. Tumer, A. Bulut, Spectrochim. Acta
916–929.
A 67 (2007)