New tetrachlorocyclodiphosph(V)azane complexes of Co(II), Ni(II), and Cu(II): Preparation, characterization, solid state electrical conductivity, and biological activity studies

Article abstract of DOI:10.1080/10426500701839858

Tetrachlorocyclodiphosph(V)azane of thiazole, H2L (1,3-diphenyl -2,4-bis(3-phenyl-2-iminothiazole)-2,2,4,4-tetrachlorocyclodiphos(V)azane, reacts with stoichiometric amounts of transition metal salts such as Co(II), Ni(II), and Cu(II) to afford colored complexes in a moderate to high yield. The structure of the isolated complexes was suggested based on elemental analyses, IR, molar conductance, UV-Vis, 1H and 31P NMR, mass spectra, solid reflectance, magnetic susceptibility measurements and dark electrical conductivity of solid state from room temperature up to 450 k. The data obtained obeyed the relation σ = σ° exp (-E/2kT) over the temperature range 30-150°C. The observed conductivities of the different complexes follow the order Co < Ni < Cu. It is clear that this trend is depending on the decreasing of the ionic radii and the increasing stability of metal complexes. The calculated mobility of charge carriers is ranged from 10-5 to 10-9 cm2/V s suggesting that the conduction of the studied complexes takes place by hopping mechanism. The solid-state electrical conductivity obtained reveals that the metal complexes behave as semiconducting materials. The powder XRD studies confirm the amorphous nature of the complexes. From the elemental analyses data, 1: 2 (H2L: M) ratio is suggested and the complexes are found to have the general formula [(MX2)2(H2L)(H2O)m]. nH2O where M = Co(II) (X = SCN, n = 2, m = 0), Ni(II) (X = Cl, n = 4, m = 4), and Cu(II) (X = Cl, n = 2, m = 0). The complexes have been investigated in solution by the spectrophotometric molar ratio and conductometric methods. IR spectra show that the ligand is coordinated to the metal ions in a bidentate manner with NN donor sites of the imine NH and thiazole N. The UV-Vis, solid reflectance, and magnetic-moment data have shown that the ligand is coordinated to the metal ions in an octahedral, tetrahedral, or square planar manner. The molar conductance data show that the complexes are nonelectrolytes. The prepared complexes showed high to moderate bactericidal activity compared with the ligand. Copyright Taylor & Francis Group, LLC.

Full text of DOI:10.1080/10426500701839858

This article was downloaded by: [University of Cambridge]
On: 16 October 2014, At: 14:17
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954
Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH,
UK
Phosphorus, Sulfur, and Silicon
and the Related Elements
Publication details, including instructions for
authors and subscription information:
http://www.tandfonline.com/loi/gpss20
New
Tetrachlorocyclodiphosph(V)azane
Complexes of Co(II), Ni(II),
and Cu(II): Preparation,
Characterization, Solid State
Electrical Conductivity, and
Biological Activity Studies
Abdel-Nasser M. A. Alaghaz a & Salwa A. H. Elbohy b
a Department of Chemistry, Faculty of Science , Al-
Azhar University (for Boys) , Nasr City, Cairo, Egypt
b Department of Chemistry, Faculty of Science , Al-
Azhar University (for Girls) , Nasr City, Cairo, Egypt
Published online: 28 Jul 2008.
To cite this article: Abdel-Nasser M. A. Alaghaz & Salwa A. H. Elbohy (2008) New
Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II): Preparation,
Characterization, Solid State Electrical Conductivity, and Biological Activity Studies,
Phosphorus, Sulfur, and Silicon and the Related Elements, 183:8, 2000-2019, DOI:
10.1080/10426500701839858
To link to this article: http://dx.doi.org/10.1080/10426500701839858
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the
information (the “Content”) contained in the publications on our platform.
However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness,

or suitability for any purpose of the Content. Any opinions and views
expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the
Content should not be relied upon and should be independently verified with
primary sources of information. Taylor and Francis shall not be liable for any
losses, actions, claims, proceedings, demands, costs, expenses, damages,
and other liabilities whatsoever or howsoever caused arising directly or
indirectly in connection with, in relation to or arising out of the use of the
Content.
This article may be used for research, teaching, and private study purposes.
Any substantial or systematic reproduction, redistribution, reselling, loan,
sub-licensing, systematic supply, or distribution in any form to anyone is
expressly forbidden. Terms & Conditions of access and use can be found at
http://www.tandfonline.com/page/terms-and-conditions

Phosphorus, Sulfur, and Silicon, 183:2000–2019, 2008
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500701839858
New Tetrachlorocyclodiphosph(V)azane Complexes
of Co(II), Ni(II), and Cu(II): Preparation, Characterization,
Solid State Electrical Conductivity, and Biological
Activity Studies
Abdel-Nasser M. A. Alaghaz1 and Salwa A. H. Elbohy2
1Department of Chemistry, Faculty of Science, Al-Azhar University
(for Boys), Nasr City, Cairo, Egypt
2Department of Chemistry, Faculty of Science, Al-Azhar University
(for Girls), Nasr City, Cairo, Egypt
Tetrachlorocyclodiphosph(V)azane of thiazole, H2L (1,3-diphenyl -2,4-bis(3-phenyl-
2-iminothiazole)-2,2,4,4-tetrachlorocyclodiphos(V)azane, reacts with stoichiometric
amounts of transition metal salts such as Co(II), Ni(II), and Cu(II) to afford colored
complexes in a moderate to high yield. The structure of the isolated complexes was
suggested based on elemental analyses, IR, molar conductance, UV-Vis, 1H and 31
P
NMR, mass spectra, solid reflectance, magnetic susceptibility measurements and
dark electrical conductivity of solid state from room temperature up to 450 k. The
data obtained obeyed the relation σ = σ◦ exp(−E/2kT) over the temperature range
30–150◦C. The observed conductivities of the different complexes follow the order
Co<Ni<Cu. It is clear that this trend is depending on the decreasing of the ionic
radii and the increasing stability of metal complexes. The calculated mobility of
charge carriers is ranged from 10−5 to 10−9 cm2/V s suggesting that the conduc-
tion of the studied complexes takes place by hopping mechanism. The solid-state
electrical conductivity obtained reveals that the metal complexes behave as semi-
conducting materials. The powder XRD studies confirm the amorphous nature of
the complexes. From the elemental analyses data, 1: 2 (H2L: M) ratio is suggested
and the complexes are found to have the general formula [(MX2)2(H2L)(H2O)m].
nH2O where M = Co(II) (X = SCN, n = 2, m = 0), Ni(II) (X = Cl, n = 4, m = 4),
and Cu(II) (X = Cl, n = 2, m = 0). The complexes have been investigated in solu-
tion by the spectrophotometric molar ratio and conductometric methods. IR spectra
show that the ligand is coordinated to the metal ions in a bidentate manner with
NN donor sites of the imine NH and thiazole N. The UV-Vis, solid reflectance, and
magnetic-moment data have shown that the ligand is coordinated to the metal ions
in an octahedral, tetrahedral, or square planar manner. The molar conductance
data show that the complexes are nonelectrolytes. The prepared complexes showed
high to moderate bactericidal activity compared with the ligand.
Keywords Electrical conductivity; electronic; IR; magnetic moment; 31P NMR; tetra-
chlorocyclodiphosph(V)azane metal complexes
Received 17 July 2007; accepted 15 September 2007.
Address correspondence to A. M. A. Alaghaz, Chemistry Department, Faculty of
Science (Boys), Al-Azhar University, Nasr-City, Cairo, Egypt. E-mail: aalajhaz@hotmail.
com
2000

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2001
INTRODUCTION
In recent years, the structural feature of four-membered N2P2 ring com-
pounds in which the coordination number of P varies from three to
five have attached considerable attention.1,2 Heterocycles with P C,
P N, P O, and P S bonds, in addition to their great biochemical
and commercial importance,3,4 play a major role in some substitu-
tion mechanisms as intermediates or as transition states.3,4 The reac-
tion of hexachlorocyclod-iphosph(V)azanes with aromatic and aliphatic
amines, active methylene containing compounds, and bifunctional
reagents have been investigated in some detail.5–7
The present work aims chiefly to prepare the metal complexes
of tetrachlorocyclodiphos(V)phazanes of thiazole. In this work, novel
tetrachlorocyclodiphosph(V)azanes of thiazole (H2L) was prepared
and its behavior towards some transition metal ions was stud-
ied using different techniques such as elemental analyses, IR, 1H
NMR, and 31P NMR, solid reflectance, mass spectra, molar conduc-
tance, magnetic moment, UV-Vis, and mass spectra. The DC electri-
cal behavior of 1,3-diphenyl-2,4-bis(3-phenyl-2-iminothiazole)-2,2,4,4-
tetrachlorocyclodiphos(V)azane compound and its cobalt(II), nickel(II),
and copper(II) complexes at different temperatures is investigated. The
mechanism of conduction is explained. Also, the bactericidal activities
of these compounds were studied. The proposed structure for H2L is
shown in Figure 1.
EXPERIMENTAL
All chemicals used were of analytical reagent grade. They included
Co(SCN)2, Ni(CH3COO)2·4H2O, and CuBr2, 3-phenyl-2aminothiazole
and phosphorus pentachloride supplied from BDH. The solvents used
were ethanol, benzene, dimethylformamide (DMF), and deuterated
dimethyl sulfoxide (DMSO).
Preparation of Ligand
The solid of 3-phenyl-2-aminothiazole (II) (1.76 g, 0.01 mmol) was
added in small portions to a well stirred solution of the 1,3-diphenyl-
2,2,2,4,4,4-hexachlorocyclodiphosph(V)azane (I) (3.56 g, 0.005 mmol)
in 100 ml acetonitrile over a half-hour period. After the complete
addition, the reaction mixture was heated under reflux for 2 h
with continuous stirring. After completion of the reaction (HCl gas
ceased to evolve), the reaction mixture was filtered while hot and
the filtrate was left to cool at room temperature. The obtained solid

2002
A. M. A. Alaghaz and S. A. H. Elbohy
FIGURE 1 Structure of ligand H2L:1,3-diphenyl-2,2,4,4-tetrachloro,2ꢀ,4ꢀ-
bis(2-imino-3-phenylthiazole) cyclodiphosph(V)azane.
(bright yellow) was filtered washed several times with acetonitrile,
and dried in vacuo to give the corresponding 1,3-diphenyl-2,4-bis(3-
phenyl-2-iminothiazole)-2,2,4,4-tetrachlorocyclodiph-os(V)azane (H2L)
(Figure 1). Yield = 88.6%; m.p. = 196◦C; elemental analysis calculated
(found) for C30H24N6P2S2Cl4 (736.44): C = 48.9% (48.3%), H = 3.3%
(3.2%), N = 11.4% (11.2%), P = 8.4% (8.4%), S = 8.7% (8.7%).
Preparation of Complexes
A hot solution (60◦C) of the metal salts [Co(SCN)2 (0.35 g;
0.002 mol)], [Ni(CH3COO)2.4H2O (0.497; 0.002)] or [CuBr2 (0.466;
0.002)] in 50 mL absolute ethanol was added dropwise to a
hot solution of 1,3-diphenyl-2,4-bis(3-phenyl-2-iminothiazole)-2,2,4,4-
tetrachlorocyclodiphos(V)azane (H2L) (0.736 g; 0.001 mol) in 100 mL
absolute ethanol in a 2:1 metal-to-ligand molar ratio at room tem-
perature with continuous stirring. After complete addition of the hot

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2003
metal-salt solution, the reaction mixture was heated under reflux for
about 2 h under dry conditions. The complexes obtained were washed
with absolute ethanol then with dry diethyl ether and dried in vacuo.
The analytical data of both ligand and its metal complexes are listed in
Table I.
Methods
Microanalytical analysis of C, H, N, and S were carried out and phos-
phorus was determined gravimetrically as phosphoammonium molyb-
date using the R. Voy method.8 Infrared spectra were recorded in the
solid state on a Mattson 5000 FTIR spectrometer using KBr disc tech-
nique. The absorbance of solutions were measured in the UV/VIS range
(200–800 nm) using Unicam spectrophotometer model UV 2–100 and
1
1 cm matched quartz cells. The H NMR spectrum of the ligand was
recorded on a Varian FT-290.90 MHz spectrometer in deutrated DMSO
using TMS as an internal standard. 31P NMR spectra were run, rel-
ative to external H3PO4 (85%), with a Varian FT-80 spectrometer at
365 MHz. Magnetic measurements were recorded by the Gouy method
at room temperature using a magnetic susceptibility balance (Johnson
Matthey), Alfa product, Model No. (MK). Diamagnetic corrections were
calculated from Pascal’s constants. The conductometric measurements
in solutions were carried out using conductivity TDS model 72. Metal
contents were determined by titration against standard EDTA after
complete decomposition of the complexes with aqua regia in a Kjeldahl
flask several times. The X-ray-diffraction patterns of the samples were
recorded with a Rikagu Geigerflex diffractometer using Cu Kα radia-
tion. The Antimicrobial activity was performed using DMF as solvent
at Fermentation Biotechnology and Applied Microbiology (FERM-BAM)
Center, Al-Azhar University, Egypt. The test was done using diffusion
agar technique. Conductivity measurements were made on discs hav-
ing 1mm thickness of 1,3-diphenyl-2,4-bis(3-phenyl-2-iminothiazole)-
2,2,4,4-tetrachlorocyclodiphos(V)azane and its complexes sandwiched
between two copper electrodes. The conductivity cell used was the same
as that reported before.9 The electrical conductivity was measured in
the temperature range 30–150◦C. The activation energies were calcu-
lated using the equation σ = σ◦ exp (−E/2kT).
RESULTS AND DISCUSSION
The ligand was found to be soluble in CHCl3, acetone, ethanol, THF,
methanol, DMSO, DMF, ethyl acetate, and insoluble in diethyl ether
and water, slightly soluble in benzene and n-hexane. The structure of

2004

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2005
the ligand (H2L) was elucidated by elemental analyses, IR, electronic,
1H PNMR techniques, and 31P NMR techniques.
IR Spectra
The assignments of the important bands of the free ligand are given
in Table II. The spectra reveal the characteristic bands of the νP−NH
stretching vibrations of the ligand at 2620 cm−1 which is similar to
those assigned by Abd-Ellah et al.10 and Pustinger et al.11 The band
appeared at 3053 cm−1 is attributed to the νNH stretching vibration.
The νP–Cl stretching vibration is observed at 522 cm−1 12,13
The band
.
at 1223 cm−1 was assigned to the νP–N stretching vibration.14,15 Bands
appear in the range 1622–1409 cm−1 may be attributed to νC=C of the
aromatic rings and attached compounds (II).16 Moreover, the IR spectra
showed weak band at 621 cm−1 due to the νC–S stretching vibration of
thiazole ring. The weak band observed at 2929 cm−1 is due to aromatic
C−H stretching vibrations.17
Electronic Spectra
The fact that the expected band at 272 nm,18 characteristic for the de-
localization of the nonbonding electrons on the nitrogen atoms within
the phosphazo ring of the dimeric structure was observed in the spec-
trum of ligand (H2L), suggested the presence of the phosphazo ring.
The bathochromically shifted band observed at 284 nm for the ligand
relative to that of the dimer (I) is explained to be due to the replace-
ment for one chlorine atom of each phosphorus atom by the 2-amino-
3-phenylthiazole. The new band observed at 350 nm is attributed to
the n-π* transition of attached compound (II), which is absent in the
corresponding dimer (I) and this is considered as an evidence for the
ligand formation.
Mass Spectrum
The possible fragmentation pathways of ligand (H2L) (Scheme 1)
showed the expected fragments, which confirm the proposed structure
of this ligand. The base peak was observed in the spectrum at 92.
1H and 31P-NMR Spectrum
The 1H NMR spectrum of the ligand (H2L) showed the following charac-
teristic proton signals at: δ (7.51) ppm is assigned for aromatic protons
Ar H and abroad signal at δ (8.97) ppm is assigned for N H proton,
which disappeared on the addition of D2O due to the proton exchange.

2006

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2007
SCHEME 1 Fragmentation pattern for ligand (H2L).
The 31P NMR of the ligand records a signal at δ = 14.4, 10.6 ppm, which
supports the phosphazo-ring structure.
Metal Complexes
The complexes were found to be soluble in DMSO, DMF and THF and
insoluble in CHCl3, ethanol, diethyl ether, and water; they were slightly

2008
A. M. A. Alaghaz and S. A. H. Elbohy
soluble in acetone. The chemical behavior of H2L towards transition-
metal cations was our goal in this article. The metal cations selected
for this purpose were Co(II), Ni(II), and Cu(II). When a mixture of one
mol of H2L in dry ethanol was reacted with two moles of the metal
salts in acetonitrile, a change in color was observed and the complex
compounds precipitated. The products were purified by washing with
absolute ethanol, and gave elemental analysis compatible with the gen-
eral formula [(MX2)2(H2L)(H2O)m]. nH2O, where M = Co(II) (X = SCN,
n = 2, m = 0), Ni(II) (X = OCOCH3, n = 4, m = 4), and Cu(II) (X = Br,
n = 2, m = 0). Accordingly, the complexes are prepared following the
general equation:
2MXn + H2L + mH2O → [(MX2)2(H2L)(H2O)m] . nH2O
(1)
where M = Co(II) (X = SCN, n = 2, m = 0), Ni(II) (X = OCOCH3, n =
4, m = 4), and Cu(II) (X = Br, n = 2, m = 0).
The analytical data of the isolated complexes are listed in Table I.
Further, the proposed structures of the complexes of H2L is confirmed
using different physicochemical tools such as IR, molar conductance,
UV-Vis, solid reflectance, magnetic moment, XRD, and solid state elec-
trical conductivity.
IR Spectra
A detailed interpretation of the IR spectra of H2L and the effect of bind-
ing with Co(II), Ni(II), and Cu(II) ions on the vibrational frequencies
of the free H2L ligand are discussed. The IR spectra of the free ligand
and its metal chelates were carried out in the 4000–400 cm−1 range
(Table II). IR spectrum of the ligand revealed a medium band at 1595
cm−1 ν(C=N) thiazole ring, which is shifted to lower frequency at about
10 cm−1 after complexation, which also indicates that it has been af-
fected upon coordination to metal ions. In the IR spectrum of all the
complexes, IR band is observed between 624–694 cm−1, which is at-
19
tributed to the ν
stretching vibrations. There are also two bands
(M–N)
affected after complexation belonging to the thiazole skeleton stretch-
ing and benzene ν(C=C) stretching vibration at 1279 and 1409 cm−1
,
respectively, which clearly shows that ligands coordinated to the metal
ions from nitrogen atom of imine NH and nitrogen atom of thiazole
groups.20 The results of IR spectra of the metal complexes show ab-
sorption bands of both νC=N and νN–H at lower frequencies than those
of the free ligand H2L, indicating that the metal ions are coordinated
to the nitrogen atoms of both C N and NH groups of the ligand H2L.
Practically unchanged ν(C–S–C) vibration at 1027 cm−1 of the thiazole

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2009
ring21,22 indicates that the thiazole group does not coordinate to metal
from the sulfur atom.
The acetato complex has band at 1593 cm−1 and 1409 cm−1 can
be assigned to νas(CO2) and νs(CO2) fundamental stretching bands,
respectively, which are in agreement with the acetate group being
monodentate23 because the difference ꢂ (ꢂ = νas(CO2) − νs(CO2)] is
1593−1409 = 148 cm−1. The band at 1409 cm−1 is due to the νs(CO2)
mode of both acetate and H2L ligand.
The ν(Cu Br) band is observed at 464 cm−1, which showed terminal
rather than bridging bromine for the bromo complex.23 In the complex
with NCS− group, it seems to be that NCS− coordinated through the
nitrogen atom, since ν(NCS) are observed in region of 2066 cm−1.24,25
All complexes showed broad band around 3500–3390 cm−1 due to ν(OH)
from water molecules. This band is absent in the ligand.26The appear-
ance of a medium-to-strong bands in the stretching vibration region
between 831 and 753 cm−1 in the spectra of the Ni(II) complex were
attributed to coordinated water molecules.23 The presence of acetate,
thiocyanate, or bromide ions in the structural configuration of the com-
plexes suggests that H2L act as a bidentate monoanionic molecule dur-
ing complexation with the metal ions. The characteristic bands corre-
sponding to the νP–NH, νP–Nand νP–Cl which were associated with all
the investigated complexes are collected in Table II.
From these observations, it was suggested that the imine nitrogen
and the nitrogen atom in thiazole ring are involved in the complexation
reaction as donor atoms.
Spectrophotometric Measurements of Solution
Stoichiometry
The absorption spectra of the Co2+, Ni2+, and Cu2+ complexes are shown
in Figure 2. The diagrams in Figure 3, consist of two linear portions in-
tersecting at 1:2 [ligand]/[M2+], where M2+ corresponding to Co2+, Ni2+
,
and Cu2+ respectively, indicating the formation of 2M: IL species.27 This
is in agreement with the elemental analyses and conductometric anal-
yses data.
Conductometric Titration
In order to follow up the behavior of the ligand in solution with Co (II),
Ni (II), and Cu (II), we investigated these systems using conductometric
titration method.27 In this method. 25 ml (10−4 M) of M(II) where M(II)
is Co(II), Ni(II) and Cu(II) solution in absolute ethanol was titrated

2010
A. M. A. Alaghaz and S. A. H. Elbohy
FIGURE 2 Absorption spectra for Co(II), Ni(II) and Cu(II) Complexes.
with (10−3 M) of ligand solution absolute ethanol at room temperature
25◦C and represented in Figure 4. The curves were plotted between the
conductance of the solution and the volume of ligand added. The results
show that the break in the curve occurred when the 2:1 (M:L) species
are formed in solution. The conductance of the reaction mixture was
increase continuously with complexes under investigation. The reason
for increase in conductivity after 2:1 (M: L) complexes forms may be
due to the presence of the ligand in ionic form in the medium (ethanol)
which arises the conductivity.
Molar Conductance Data
The molar conductance values in DMF at 25◦C (Table I) for the com-
plexes were found to be in the range 7.85–18.30 ꢁ−1 mol−1 cm2. The
relatively low values indicate the non-electrolytic nature of these com-
plexes. This can be accounted for by the satisfaction of the bivalent

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2011
FIGURE 3 Results of molar ratio method for Co(Il), Ni(II) and Cu(II) Com-
plexes, respectively.
of the metal by the acetate, bromide. or thiocyanate. This implies the
coordination of the anions to the metal ion centers.
Electronic Spectra and Magnetic Properties
The UV-Vis spectra of the complexes in DMF (1 × 10−3 M) show a sharp
and intense band in the region 269–281 nm, which is characteristic of
phosphazo four-membered rings.27 However, the absorptions that were
red or blue shifted with respect to the ligands depending on the types
of metal ions present. The spectra of the Ni(II), and Cu(II) complexes

2012
A. M. A. Alaghaz and S. A. H. Elbohy
FIGURE 4 Conductometric titrations for (a) Co(II), (b) Ni(II) and (c) Cu(II)
complexes, respectively.
further display a band in the range 360–439 nm, which might be as-
signed to charge-transfer transition (most probably L→M CT).28 For
the Co(II) complex, however, a d−d bands are observed at 600 and
4
4
675 nm which may attributed to the transitions T1(F) → T2(P) and
4
4T1(F) → A2(F), respectively, which is typical of tetrahedral structure
around Co(II) ion.27
The diffuse reflectance spectrum of the Co(II) complex displays
4
three bands at 13,501, 18,250, and 22,953 cm−1 assigned to the T1
4
4
4
4
4
(F) → T2(F) (ν1), T1 (F) → A2(F) (ν2), and T1 → T2(P) (ν3) transi-
tions, respectively. The band observed at 26,520 cm−1 refers to L→MCT
band. From the observed magnetic moment value (µeff = 5.26 B.M.) to-
gether with the band position in the solid reflectance spectra, the Co(II)
complex is tetrahedral with largely covalent bonds between the organic
ligand and Co(II) ion.29
The Ni(II) complex reported herein is high spin with a room tem-
perature magnetic-moment value of 2.89 B.M., which confirms the oc-
tahedral structure of this complex.29,30 The solid reflectance spectrum
of the complex shows three bands at 14,993, 17,483, and 21,552 cm−1
,
3
3
which are assigned to the 3A2g → T1g(P) (ν1), 3A2g → T1g(F) (ν2), and
3
3A2g → T2g (P) (ν3) transitions, respectively, confirming the octahedral
geometry of the Ni(II) complex.29
The solid reflectance spectrum of the Cu(II) complex gave a band at
2
17,361 cm−1, was assigned to 2B2 → E transition. The bands observed
in the range 426–414 nm were assigned to the charge transfer via L→M
(Cu2+). The observed magnetic moment of the Cu(II) complex is 1.89
B.M., which confirms the square planner structure of this complex.27

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2013
FIGURE 5 Plots of In σ versus 1000/T for Co2+, Ni2+ and Cu2+ cy-
clodiphos(V)azane complexes.
Solid-State Electrical Conductivity
Figure 5 shows the relation between log σ against 1/T for 1,3-
diphenyl-2,4-bis(3-phenyl-2-iminothiazole)-2,2,4,4-tetrachlorocyclodi-
phos(V)azane compound and its complexes. A linear behavior was
obtained for all samples. The conductivity of the free ligand is in-
creased on complexing with transition metal ions. This behavior is
attributed to the inclusion of the various metal cations in the π-electron
delocalization of the ligand.31 The observed conductivities follow the
order Co < Ni < Cu. Theoretically, if we consider the charge/radii, the
stability of the metal complexes increases as the size of the metal ion
decreases or the value of the ratio charge/radii increases. This means
that the stability increases towards the copper complex. It is apparent
that increasing stability of the complexes will increase the number
of dislocated electrons on the ligand molecule and then increase
the conductivity32 as given in (Table III). To explain the conduction
mechanism of the ligand and its complexes, it is necessary to determine

2014
A. M. A. Alaghaz and S. A. H. Elbohy
TABLE III Electrical Conductivity (σ) Data of H2L and its Metal
Complexes at 303 K
Compound
σ(Ohm−1 cm−1
)
E(ev)
n(cm−3
)
µ(cm2/V s)
H2L
1.6 × 10−8
1.8 × 10−8
2.2 × 10−8
2.8 × 10−8
0.34
0.42
0.49
0.61
8.8 × 1019
13.0 × 1018
1.9 × 1018
1.6 × 1016
1.4 × 10−7
8.5 × 10−9
7.6 × 10−8
1.2 × 10−5
[Co2)SCN)4(H2L)].2H2O
[Ni2(Ac)4(H2L) (H2O)4].4H2O
[Cu2Br4(H2L)]].2H2O
the mobility of charge carriers µ. If the density of charge carriers is
known, then the mobility can be calculated using the relation σ =
eNm, e is the electron charge. The charge carrier concentration was
determined using the relation,
n = 2[2µm∗kT/h2]1/2 exp(−E : kT).
(2)
where m∗ is the effective mass of charge carrier.The calculated mo-
bilities are ranged from 10−5 to 10−9 cm2/ V s suggesting that the
conductionof iminothiazole-cyclodiphos(V)azane ligand and its metal
complexes takes place by hopping mechanism.33
X-Ray Powder Diffraction
X-ray powder diffraction patterns in the 5◦ < 2θ < 90◦ of the com-
pounds were carried in order to obtain an idea about the lattice dy-
namics of the compound. By comparison of the obtained X-ray powder
diffraction patterns shown in Figure 6, the X-ray powder diffraction
pattern throws light only on the fact that each solid represents a defi-
nite compound of a definite structure which is not contaminated with
starting materials. This identification of the complexes was done by the
known method.34 Such facts suggest that the prepared compounds are
amorphous.
Structural Interpretation
2-Iminothiazole)-2,2,4,4-tetrachlorocyclodiphos(V)azane (H2L) form
(2M: 1L) complexes with the Co(II), Ni(II), and Cu(II) metal cations. The
structural information from these complexes is in agreement with the
data reported in this article based on the IR, molar conductance, UV-Vis,
mass, solid reflectance, XRD, solid state electrical conductivity, mag-
netic moment, and spectrophotometric molar ratio and conductometric
methods. The design and synthesis of a new bidentate ligand derived
from 3-phenyl-2-aminothiazole for use in square planar, tetrahedral, or
octahedral molecular templates have been successfully demonstrated.

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2015
FIGURE 6 XRD diagrams of: (A) Co (II), (B) Ni(II), and (C) Cu(II) complexes.
The synthesis of the ligand and its complexes proved as straightforward
as expected, giving high yields of the free ligand and its complexes in
simple, one-pot reactions. As anticipated, the ligand coordinates equato-
rially to four- or six-coordinate transition metal ions to give tetrahedral
(Co(II)), octahedral (Ni(II)), and square planar (Cu(II)), environments
around the metal ion anchor. The proposed general structures of the
complexes are shown in Figure 7. H2L ligand always coordinates via
the thiazole-N and imine-NH forming two-binding chelating sites.
Biological Activity
The disc diffusion method was used to measure the antimicrobial ac-
tivity of the complexes.35,36 The compounds under test were dissolved
in dimethylformamide (DMF) (2% w/v) and added at a concentration
of 0.5 mL/disc to Whatman number 3 filter paper, 5 mm diameter. The
biological activity of the H2L, its complexes and traivid and tavinic (as
standard compounds), were tested against bacteria because bacteriums

2016
A. M. A. Alaghaz and S. A. H. Elbohy
FIGURE 7 The proposed structure of the Co(ll), Ni(II) and Cu(lI) Complexes.
Where X = SCN or Br, M = Co2+ or Cu2+, Ac = acetate.
can achieve resistance to antibiotics through biochemical and morpho-
logical modifications.36 The antimicrobial activity was examined with
different species of gram-positive bacteria such as Staphylococcue Pyo-
gones, gram-negative bacteria such as Pseudomonas aereuguinosa and
Escherichia coli, and fungi (Candida). The data obtained are summa-
rized in Table IV. The data obtained reflect the following findings:
1. The H2L ligand has moderate activity in comparison with Staphy-
lococcus Pyogones and is less active in comparison with Escherichia
coli and Pseudomonas aereuguinosa. The remarkable activity of the
ligand may arise from the thiazole-N and the imine -NH groups,
which may play an important role in the antibacterial activity,37 as
well as the presence of two imine groups which imports in elucidating
the mechanism of transformation reaction in biological systems.36
2. Antibacterial activity of the complexes towards the different organ-
isms shows a high-to-moderate activity.

2017

2018
A. M. A. Alaghaz and S. A. H. Elbohy
3. The activity of the ligand and its complexes increases as the concen-
tration increases because it is a well known fact that concentration
plays a vital role in increasing the degree of inhibition.38
REFERENCES
[1] S. S. Kumaravel and S. S. Krishnamurthy, J. Chem. Soc. (Dalton Trans.), 1, 1119,
1121 (1990).
[2] M. S. Balakrishna, R. M. Abhyankar, and J. T. Mague, J. Chem. Soc. (Dalton Trans.),
4, 1407 (1990).
[3] M. S. Balakrishna, R. Panda, and J. T. Mague, Inorg. Chem., 40, 5620 (2002).
[4] (a) S. Priva, M. S. Balakrishna, J. T. Mague, and S. M. Mobin, Inorg. Chem., 42, 1272
(2003); (b) M. S. Balakrishna, K. Ramaswamy, and R. M. Abhyankar, Organomet.
Chem., 560, 131 (1998).
[5] E. Ibrahim, I. M. Abd-Ellah, L. S. Shaw, and I. Alnaim, Phosphorus, Sulfur and
Silicon, 33, 109 (1987).
[6] A. N. Al-Khazandar, R. S. Farag, and I. M. Abd-Ellah, Proc. Ind. Natn. Sci. Acad.,
60A, 6, 793 (1994).
[7] I. M. Abd-Ellah, E. H. M. Ibrahim, and A. N. Al-Khazandar, Phosphorus, Sulfur, 13,
13 (1987).
[8] R. Voy, Chem. Ztg. Chem. Apparatus, 21, 441 (1897).
[9] M. A. Ahmed and F. A. Eadwan, J. Phys. Chem. Solids, 49, 1385 (1988).
[10] I. M. Abd-Ellah, Y. Al-Shaibi, A. A. Ba-issa, and M. S. El-Hammadi, J. Phosphorus,
Sulfur, and Silicon, 139, 29 (1998).
[11] J. V. Pustinger, W. T. Cove, and M. L. Neilsen, Spectrochim. Acta, 15, 909 (1959).
[12] D. E. C. Corbridge, J. Appl. Chem., 6, 456 (1956).
[13] L. C. Thomas and R. A. Chittenden, Chem. Ind. London, 1913 (1961).
[14] A. M. A. Alaghaz and H. A. Gumaa, Al-Azhar Bull. Sci., 17(2), 73 (2006).
[15] R. B. Harvey and J. E. Mayhood, Can. J. Chem., 33, 1552 (1955).
[16] L. C. Scheinman, Introduction to Spectroscopic Methods for the Identification of
Organic Compounds, (Pergamon, Elmsford, 1970) vol. 1, p. 173.
[17] S. E. Wiberley, S. C. Bunce, and W. H. Bauer, Anal. Chem., 32, 217 (1960).
[18] M. Becke-Goehring and B. Z. Bopple, Anorg. Chem., 322, 239 (1963).
[19] A. Nakamura, A. Konishi, S. Otsuka, J. Chem. Soc. Dalton Trans., 488 (1979).
[20] W. Li, Q. Wu, Y. Ye, M. Lou, L. Hu, Y. Gu, F. Niu, and J. Hu, Spectrochim. Acta, Part
A, 60, 2343 (2004).
[21] R. Castro, J. A. Garcia-Vazquez, J. Romero, and A. Sousa, Polyhedron, 12, 47 (1993).
[22] R. Castro, J. A. Garcia-Vazquez, J. Romero, A. Sousa, Polyhedron, 12, 2241 (1993).
[23] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Com-
pounds (Wiley, New York, 1978).
[24] V. B. Rana, D. P. Singh, P. Singh, M. P. Teotia, Trans. Met. Chem., 6, 36 (1981).
[25] R. A. Bailey, S. L. Kozak, T. W. Michelsen, W. N. Mills, Coord. Chem. Rev., 6, 407
(1971).
[26] R. Shanti, K. S. Nagaraja, M. R. Udupa, Ind. J. Chem., 29A, 189 (1990).
[27] I. M. Abd-Ellah, B. A. El-Sayed, M. A. El-Nawawy, and A. M. A. Alaghaz, J. Phos-
phorus, Sulfur, and Silicon, and The Related Elements, 177, 2895 (2002).
[28] G. G. Mohamed and Z. M. Zaki, Synth. React. Inorg. Met.-Org. Chem., (2004), 34,
1497 (2004).
[29] F. A. Cotton, G. Wilkinson, C. A. Murillo, and M. Bochmann, Advanced Inorganic
Chemistry (Wiley, New York, 1999), 6th ed.

Tetrachlorocyclodiphosph(V)azane Complexes of Co(II), Ni(II), and Cu(II) 2019
[30] A. M. A. Alaghaz and M. M. El-Desoky, Al-Azhar Bull. Sci., 17(2), 1 (2006).
[31] (a) A. M. A. Alaghaz, Synthesis and Physicochemical Studies on Some Organophos-
phorus Metal Complexes, Ph.D. Thesis, Al-Azhar University (Boys), (2004); (b) N. F.
Mott and E. A. Davis, Electronic Processes in Non-Crystalline Materials (Clarendon
Press, Oxford, 1971).
[32] (a) A. M. A. Alaghaz, Spectral and Electrical Studies On Some Organo-Phosphorus
Metal, M. Sc.. Thesis, Al-Azhar University (Boys), (2001); (b) D. F. Shriver, P. W.
Atkins, and C. H. Langford, Inorganic Chemistry (Oxford University, Oxford, 1996).
[33] D. A. Seanor, Electrical Properties of Polymers (Academic Press, New York, 1982).
[34] B. D. Cullity, Elements of X-ray Diffraction (Addison-Wesley Inc., 1993), 2nd ed.
[35] M. A. Ibrahim, A. A. H. Ali, and F. M. Maher, J. Chem. Techn. Biotechnol., 55, 217
(1992).
[36] I. M. Abd-Ellah, M. E. Hussein, A. N. El-Khazandar, and R. S. Farag, Oriental Chem.,
7, 121 (1991).
[37] A. S. A. Zidan, Phosphorus, Sulfur, and Silicon, 178, 567 (2003).
[38] A. Chaudhary and R. V. Singh, Phosphorus, Sulfur, and Silicon, 178, 603 (2003).