Studies on the chelation of cyclodiphosph(V)azane complexes of Co(II), Ni(II), Cu(II), and Pd(II): Preparation, characterization, thermal, solid state electrical conductivity, and biological activity studies

Article abstract of DOI:10.1080/10426500802505507

Cyclodiphosph(V)azane of chromene, (1,3-diphenyl-2,4-bis(3-amino-9- methoxy1-tolyl-3H-benzo[f]chromene-2-carbonitrile)-2,2,4,4- tetrachlorocyclodiphosph(V)azane (III), reacts with stoichiometric amounts of transition metal salts such as Co(II), Ni(II), Cu

Full text of DOI:10.1080/10426500802505507

This article was downloaded by: [University of Auckland Library]
On: 27 November 2014, At: 14:25
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
Studies on the Chelation
of Cyclodiphosph(V)azane
Complexes of Co(II), Ni(II),
Cu(II), and Pd(II): Preparation,
Characterization, Thermal,
Solid State Electrical
Conductivity, and Biological
Activity Studies
Abdel-Nasser M. A. Alaghaz a , Reda A. Ammar b
Hany M. Mohamed a
&
a Department of Chemistry, Faculty of Science , Al-
Azhar University , Nasr City, Cairo, Egypt
b Department of Chemistry, Faculty of Science , Al-
Azhar University (Girls) , Nasr City, Cairo, Egypt
Published online: 04 Sep 2009.
To cite this article: Abdel-Nasser M. A. Alaghaz , Reda A. Ammar & Hany M. Mohamed
(2009) Studies on the Chelation of Cyclodiphosph(V)azane Complexes of Co(II), Ni(II),
Cu(II), and Pd(II): Preparation, Characterization, Thermal, Solid State Electrical
Conductivity, and Biological Activity Studies, Phosphorus, Sulfur, and Silicon and the
Related Elements, 184:9, 2472-2490
To link to this article: http://dx.doi.org/10.1080/10426500802505507
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, 184:2472–2490, 2009
Copyright © Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426500802505507
Studies on the Chelation of Cyclodiphosph(V)azane
Complexes of Co(II), Ni(II), Cu(II), and Pd(II): Preparation,
Characterization, Thermal, Solid State Electrical
Conductivity, and Biological Activity Studies
Abdel-Nasser M. A. Alaghaz,1 Reda A. Ammar,2
and Hany M. Mohamed1
1Department of Chemistry, Faculty of Science, Al-Azhar University,
Nasr City, Cairo, Egypt
2Department of Chemistry, Faculty of Science, Al-Azhar University
(Girls), Nasr City, Cairo, Egypt
Cyclodiphosph(V)azane of chromene, (1,3-diphenyl-2,4-bis(3-amino-9-methoxy-
1-tolyl-3H-benzo[f]chromene-2-carbonitrile)-2,2,4,4-tetrachlorocyclodiphosph(V)-
azane (III), reacts with stoichiometric amounts of transition metal salts such
as Co(II), Ni(II), Cu(II), and Pd(II) to afford colored complexes in a moderate
to high yield. The structure of the isolated complexes was suggested based on
1
13
31
elemental analyses, IR, molar conductance, UV-Vis, H,
C, and
P-NMR,
magnetic susceptibility measurements, and dark electrical conductivity of solid
state from room temperature up to 450 K. The complexes have been investigated in
solution by spectrophotometric molar ratio and conductometric methods. Kinetic
and thermodynamic parameters were computed from the thermal decomposition
data using the Coats and Redfern method. The prepared complexes showed high
to moderate bactericidal activity compared with the ligand.
Keywords Chromene; cyclodiphosph(V)azane; electrical conductivity; electronic; mag-
netic moment; 31P NMR, IR
INTRODUCTION
The reaction of hexachlorocyclodiphosph(V)azanes with aromatic and
aliphatic amines, active methylene-containing compounds, and bifunc-
tional reagents and their metal complexes have been investigated.1−6 In
the present work, the interaction of hexachlorocyclodiphosph(V)azane
(I) with aminochromene derivative and its metal complexes have been
reported. The proposed structure for III is shown in Scheme 1.
Received 20 May 2008; accepted 25 September 2008.
Address correspondence to A. M. A. Alaghaz, Department of Chemistry, Faculty of Sci-
ence (Boys), Al-Azhar University, Nasr City, Cairo, Egypt. E-mail: aalajhaz@hotmail.com
2472

Chelation of Cyclodiphosph(V)azane Complexes
2473
SCHEME 1 Structure of ligand III: 1,3-diphenyl-2,2,4,4-tetrachloro-
2ꢀ,4ꢀ-bis(3-amino-9-methoxy-1-p-tolyl-3H-benzo[f]chromene-2-carbonitrile) cy-
clodiphosph(V)azane.
RESULTS AND DISCUSSION
A new aminocyclodiphosph(V)azane-based ligand (III) was synthe-
sized by the reaction between 1,3-diphenyl-2,2,2,4,4,4-hexachlorocyclo-
diphosph(V)azane (I) and 3-amino-9-methoxy-1-phenyl-3H-benzo[f]ch-
romene-2-carbonitrile as shown in Scheme 1. The ligand was found to
be soluble in CHCl3, acetone, ethanol, THF, methanol, DMSO, DMF,
acetone, and ethyl acetate and insoluble in diethyl ether and water,
slightly soluble in benzene and n-hexane. The structure of the ligand
(III) was elucidated by elemental analyses (Table I), IR, electronic, 1H,
13C, 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-Ellah7 and Pustinger.8 The band that appeared
at 3153 cm−1 is attributed to the νNH stretching vibration. The band
observed at 2218 cm−1 is ascribed to the νC N stretching vibration
that appeared at 2182 cm−1 in compound (II). The shift of this band to
higher frequency in the ligand is considered as evidence for the ligand
formation. The band at 1226 cm−1 was assigned to the νP stretching
N
vibration.9−12 The νP
stretching vibration is observed at 490 cm−1 13
.
Cl
Bands appearing in the range 1622–1409 cm−1 may be attributed to
13
νC
.
Moreover, the IR spectra showed a weak band at 879 cm−1 due
C
to the νC
stretching vibration of chromene ring.14 The weak band
O
observed at 2929 cm−1 is due to aromatic C H stretching vibrations.15

2474

Chelation of Cyclodiphosph(V)azane Complexes
2475
TABLE II Characteristic IR Stretching Vibration Bands (cm−1)a of
the Ligand (III) and Its Metal Complexes (IVa–d)
Compd. no.
ν(NH)
ν(M−Cl)
ν(P−N)
ν(P−N)
ν(M−N)
ν(P−NH)
ν(C≡N)
III
3153 br
3126 br
3125 br
3128 br
3123 br
—
490 m
488 m
488 m
484 m
492 m
1226 m
1186 m
1198 m
1187 m
1196 m
—
2620 m
2619 m
2620 m
2620 m
2620 m
2218 v.s
2203 m
2203 s
2206 m
2200 m
IVa
IVb
IVc
IVd
250 m
297 w
300 w
298 w
667 w
685 m
694 m
684 m
av.s = very strong, s = strong, m = medium, w = weak, br = broad.
Electronic Spectra
The fact that the expected band at 275 nm,16 characteristic for the
delocalization of the nonbonding electrons on the nitrogen atoms
within the phosphazo ring of the dimeric structure was observed in
the spectrum of ligand (III), suggested the presence of the phosp-
hazo ring. The bathochromically shifted band observed at 287 nm
for the ligand relative to that of the dimer (I) is explained to be
due to the replacement for one chlorine atom of each phospho-
rus atom by the 1,3-diphenyl-2,4-bis(3-amino-9-methoxy-1-phenyl-3H-
benzo[f]chromene-2-carbonitrile. 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 evidence
for the ligand formation.
Metal Complexes
The chemical behavior of III toward transition-metal cations was our
goal in this article. The metal cations selected for this purpose were
Co(II), Ni(II), Cu(II), and Pd(II). When a mixture of one mole of III
in acetonitrile was reacted with two moles of the metal salts in ace-
tonitrile, a change in color was observed and the complex compounds
precipitated. The products were purified by washing with acetoni-
trile and gave elemental analysis compatible with the general formula
[(MX2)2(III)], where M = Co(II) (X = Cl), Ni(II) (X = Cl), Cu(II) (X
= Cl), and Pd(II) (X = NO3). Accordingly, the complexes are prepared
following the general equation:
2MX2 + III + mH2O → [(MX2)2(III)]
where M = Co(II) (X = Cl, m = 0), Ni(II) (X = Cl, m = 4), Cu(II) (X =
Cl, m = 0), and Pd(II) (X = NO3, m = 0).

2476
A. M. A. Alaghaz et al.
The analytical data of the isolated complexes are listed in Table I.
The complexes was found to be soluble in DMSO, DMF, and THF and
insoluble in CHCl3, ethanol, diethyl ether, and water, slightly soluble
in acetone. Further, the proposed structures of the complexes of III
is confirmed using different physicochemical tools such as IR, molar
conductance, UV-Vis, solid reflectance, magnetic moment, and solid-
state electrical conductivity.
IR Spectra
The most important vibrational bands of the ligand and its metal
complexes are given in Table II. The results of IR spectra of the metal
complexes show absorption bands of both νC≡N and νN
at lower fre-
H
quencies than those of the free ligand III, indicating that the metal ions
are coordinated to the nitrogen atoms of both C N and N–H groups of
the ligand III. Further, in all the metal complexes, there were new
medium to weak bands observed at lower frequencies in the range
13
(250–300 cm−1) that were assigned to νM−N
.
The ν(M-Cl) band is observed at 340–348 cm−1 and 308–312 cm−1
,
which showed terminal rather than bridging chlorine for the chloro
complexes.17
The nitrato complex, having two bands at 1280 cm−1 and 1390 cm−1
corresponding to ν1 and ν4 of the nitrato groups with a separation ꢂ
of 110 cm−1, points toward monodentate coordination.17,18 The appear-
ance of a band at 1390 cm−1 in the spectrum of the complex that does
not contain ionic nitrates is most probably due to the fact that a certain
amount of coordinated nitrates transforms to ionic nitrates by pressing
KBr pellet.18 In addition, a weak band at 710 cm−1 assignable to the
ν3 mode is further support for the presence of a terminally bonded ni-
trato group.13 This has been confirmed by the band at 362 cm−1, which
pointed to the coordination of the nitrate group through oxygen.18
The characteristic bands corresponding to the νP NH, νP N, and
νNH associated with all the investigated complexes are collected in
Table II.
Spectrophotometric Measurements of Solution Stoichiometry
The absorption values of the Cu2+ complexes are shown in Table III.
The diagrams in Figure 1 consist of two linear portions intersecting
at 1:2 [ligand]/[Cu2+ ], indicating the formation of 2Cu(II):IL species.19
This is in agreement with the elemental analyses and conductometric
analyses data.

Chelation of Cyclodiphosph(V)azane Complexes
2477
TABLE III Absorption Data of Ligand (III) Solution with the
Addition of Cu2+Solution, (IVc)
Molar ratio (Cu+2: III)
Conc. of III (10−4M)
Conc. of Cu (10−4M) Absorbance
0
0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
2.0
0.157
0.164
0.171
0.172
0.181
0.183
0183
0.183
0.183
0.183
0.183
0.183
0.183
2:0.25
2:0.50
2:0.75
2:1.00
2:1.25
2:1. 50
2:1.75
2:2.00
2:2.25
2:2.50
2:0.75
2:3.00
0.25
0.50
0.75
1.0
1.25
1.50
1.75
2.0
2.25
2.50
2.75
3.0
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 a con-
ductometric titration method.21 In this method, 25 mL (10−4 M) of M(II)
where M(II) is Co(II), Ni(II), Cu(II), and Pd(II) solution in absolute
ethanol was titrated with (10−3 M) of ligand solution absolute ethanol
at room temperature 25◦C and represented in Figure 2. 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
FIGURE 1 Results of molar ratio method for Cu(II) complex.

2478
A. M. A. Alaghaz et al.
FIGURE 2 Conductometric titrations for Cu(II) complex.
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 raises the conductivity.19
Molar Conductance Data
The molar conductance values in DMF at 25◦C (Table I) for the
complexes were found to be in the range 7.85–18.30 ꢁ−1 mol−1 cm2.
The relatively low values indicate the nonelectrolytic nature of these
complexes. It also indicates the nonbonding of the chloride or nitrate
anions to the metal ions.
Electronic Spectra and Magnetic Properties
The electronic spectra of the free ligand exhibit bands at 345 and
285 nm, which could be assigned to n-π* and π–π* transitions, respec-
tively. On complexation, the lower-energy band is shifted to a red shift,
whereas the transition π–π* is slightly shifted to a blue shift.
The room-temperature magnetic susceptibility measurement of the
Co(II) complex, [Co2(III) Cl4] IVa, gave magnetic moment value µeff
of 3.54 B.M., corresponding to three unpaired electrons, which are ex-
pected for a weak field ligand. The electronic spectra of the Co(II) com-
plex as nujol mulls and/or solution in ethanol were recorded in the
range 280–900 nm. The spectra exhibit peaks at the 715 nm region,
4
which may be assigned to 4A2 → T1 (p) (ν3) and is consistent with the
tetrahedral geometry.19 The peaks observed at the 295 nm and 248 nm
regions were assigned to n-π* and π–π* transitions, respectively.19
The green Ni-complex, [Ni2(III)Cl4] IVb, gives a value µeff of 2.91
B.M., which is indicative of two unpaired electrons. The electronic spec-
tra of the Ni(II) complex IVb exhibit an absorption band near 665 nm,

Chelation of Cyclodiphosph(V)azane Complexes
2479
3
3
which may be attributable to the T1 → T1 (p), and weak bands ob-
served on the high and low energy sides of the 660 nm band have been
assigned to spin-forbidden bands.19
The Cu(II) complex, [Cu2(III) Cl4] IVc, absorbed at 698 nm was as-
2
signed to 2B2 → E transition. The bands observed in the range 425 nm
were assigned to the charge transfer via L → M (Cu2+).19 The observed
band at 280 nm was attributable to π-π*. The magnetic moment of
the Cu(II)-complex of µeff value of 2.01 B.M. is in accordance with one
unpaired electron, which is indicative of square planar structure.
Palladium complex has three spin allowed singlet–singlet d–d transi-
1
1
tions, which are 1A1g → A2g (715 nm), 1A1g → B1g (495 nm), and 1A1g
→ Eg (415 nm).20 These transitions are from the lower lying d-orbital
1
to the empty dx2−y2 orbital. The strong band at 375 nm is assignable to
a combination of M → L (charge transfer) and d–d bands.
Solid State Electrical Conductivity
Figure 3 shows the relation between log σ against 1/T for 1,3-
diphenyl-2,4-bis(3-amino-9-methoxy-1-phenyl-3H-benzo[f]-chromene-
2-carboni-trile)-2,2,4,4-tetrachlorocyclodiphosph(V)azane compound
and its complexes. A linear behavior was obtained for all samples.
The conductivity of the free ligand is increased 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.21 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 toward 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 conductivity22
as given in Table IV. To explain the conduction mechanism of the
ligand and its complexes, it is necessary to determine 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, where e is
the electron charge. The charge carrier concentration was determined
using the relation
n = 2[2 µm∗kT/h2]1/2 exp(−E/kT)
where m∗ is the effective mass of charge carrier. The calculated mobili-
ties range from 10−5 to 10−9 cm2/Vs, suggesting that the conduction of

2480
A. M. A. Alaghaz et al.
FIGURE 3 Plots of ln σ versus 1×10−3/T for the ligand (III) and its Cu2+(IVc)
complex.

Chelation of Cyclodiphosph(V)azane Complexes
2481
TABLE IV Values of the Electrical Conductivity (σ) and Thermal
Activation Energy of the Ligand (III) and Its Complexes (IVa−d) at
303 K
Compound
σ(Ohm−1cm−1
)
E(eV)
n(cm−3
)
µ(cm2/V s)
III
1.50 × 10−8
1.8 × 10−8
2.12 × 10−8
2.64 × 10−8
2.83 × 10−8
0.33
0.36
0.45
0.61
0.68
8.63 × 1019
12.82 × 1018
1.83 × 1018
1.30 × 1016
1.11 × 1016
1.11 × 10−7
8.25 × 0−9
7.83 × 10−8
1.37 × 10−5
1.26 × 10−4
IVa
IVb
IVc
IVd
chromene-cyclodiphosph(V)azane ligand and its metal complexes takes
place by hopping mechanism.23
X-Ray Diffraction Characterization
Unit cell parameters were found by using trial and error methods
as follows: the sample Co is monoclinic with the unit cell parameters
a = 4.934 Å, b = 4.122 Å, c = 13.03 Å, β = 98.64◦, and cell volume V =
239.30 3 Å3. Diffraction data, i.e., 2θ (observed), ꢂ2θ, and indices of the
N-Co sample, are calculated using these unit cell parameters.24
The N-Ni sample is tetragonal with the cell parameters a = 6.721 Å,
c = 9.653 Å, c/a = 1.4211, and cell volume V = 427.598 Å3. The N-Cu
sample is triclinic with the cell parameters24 a = 8.300 Å, b = 7.910
Å, c = 6.7455 Å, α = 100.09◦, β = 130.13◦, γ = 113.02◦, and cell volume
V = 290.553 Å.3
ESR Spectrum of Cu(II) Complex
X-band ESR spectrum of the Cu(II) (IVc) complex was recorded in
the solid state at 25◦C. The spectrum exhibits one broad band with g =
2.01 for complex (IVc). The shape of the spectrum is consistent with the
square planar geometry around the Cu(II) environment in the complex
(IVc).25
Kinetics of Thermal Decomposition
Recently, there has been increasing interest in determining the rate-
dependent parameters of solid-state nonisothermal decomposition re-
actions by analysis of TG curves.26 Thermogravimetric (TG) and differ-
ential thermogravimetric (DTG) analyses were carried out for Co(II),
Ni(II), Cu(II), and Pd(II)–III complexes in ambient conditions. The cor-
relations between the different decomposition steps of the complexes

2482
A. M. A. Alaghaz et al.
with the corresponding weight losses are discussed in terms of the
proposed formula of the complexes.
The thermal decomposition of [Co(III)] complex(IVa) with the molec-
ular formula (C54H40Cl8Co2N6O4P2 [M. wt. = 1300.37]) proceeds with
two main degradation steps. The first step occurs within the temper-
ature range 485–590 K with an estimated mass loss of 51.15% (calcu-
lated mass loss = 51.35%), which reasonably accounts for the loss of
C30H27N4PCl5O fragment. The DTG curve gives an exothermic peak at
638 K (the maximum peak temperature). The second step occurs within
the temperature range 595–795 K with an estimated mass loss 36.73%
(calculated mass loss = 36.99%), which reasonably accounts for the loss
of rest of the ligand molecule, leaving 2CoO as residue. The DTG curve
gives an exothermic peak at 705 K (the maximum peak temperature).
Total estimated mass loss is 87.88% (calculated mass loss = 88.34%).
The thermal decomposition of [Ni(III)] complex (IVb) with the molec-
ular formula [C54H40Cl8N6Ni2O4P2(M.wt. = 1299.89)] also proceeds
with two main degradation steps. The first estimated mass loss of
51.23% (calculated mass loss = 51.37%) within the temperature range
592–625 K could be attributed to the liberation of C30H27N4PCl5O frag-
ment. The DTG curve gives an exothermic peak at 596 K (the maxi-
mum peak temperature). The second step occurs within the tempera-
ture range 650–815 K with an estimated mass loss 37.17% (calculated
mass loss = 37.13%), which reasonably accounts for the decomposi-
tion of remaining part of the ligand molecule (C24H13N2PCl3O) leaving
2NiO as residue. The DTG curve gives an exothermic peak at 760 K
(the maximum peak temperature). Total estimated mass loss is 88.40%
(calculated mass loss = 88.50).
The complex [Cu(III)] (IVc) with the molecular formula
[C54H40Cl8Cu2-N6O4P2(M. wt = 1309.60)] is thermally decomposed in
two successive decomposition steps. The first estimated mass loss of
43.60% (calculated mass loss = 43.58%) within the temperature range
540–590 K may be attributed to the loss of (C27H20N3P2Cl3O) fragment.
The DTG curve gives an exothermic peak at 553 K (the maximum peak
temperature). The second step occurs within the temperature range
661–853 K with the estimated mass loss 44.23% (calculated mass loss
= 44.26%), which corresponds to the loss of C27H20N3Cl5O fragment,
leaving 2CuO as residue. The DTG curve gives an exothermic peak at
770 K (the maximum peak temperature). Total estimated mass loss is
87.83% (calculated mass loss = 87.84%).
The [Pd(III)] complex (IVd) with the molecular formula (C54H40Cl4-
N10O16P2Pd2 [M. wt. = 1501.5]) is thermally decomposed in two suc-
cessive steps. The first estimated mass loss 58.73% (calculated mass

Chelation of Cyclodiphosph(V)azane Complexes
2483
loss = 58.78%) within the temperature range 558–579 K can be at-
tributed to the loss of (C45H28Cl2PN6O8) fragment. The DTG curve
gives an exothermic peak at 568 K (the maximum peak tempera-
ture). The second step occurs within the temperature range 593–698 K
with an estimated mass loss 24.87% (calculated mass loss = 24.91%),
which reasonably accounts for the loss of rest of the ligand molecule
(C9H12N4Cl2PO6), leaving 2PdO as residue with total estimated mass
loss of 83.60% (calculated mass loss = 83.69%). The DTG curve gives
an exothermic peak at 659 K (the maximum peak temperature).
The final product of decomposition at 875 K corresponds to the for-
mation of metal oxide as the end product, which was confirmed by com-
paring the observed/estimated and the calculated mass of the pyrolysis
product.
The kinetic analysis parameters such as activation energy (ꢂE∗), en-
thalpy of activation (ꢂH∗), entropy of activation (ꢂS∗), and free energy
change of decomposition (ꢂG∗) were evaluated graphically by employ-
ing the Coats–Redfern relation:27
Log[−(log(1 − α)/T2)] = log[AR/θE∗(1 − 2RT/E∗)] − E∗/2.303RT
(1)
where α is the mass loss up to the temperature T, R the gas constant,
E* is the activation energy in J mol−1, θ is the linear heating rate, and
∗
∼
the term (1 − 2RT/E ) 1. A straight line plot of left-hand side of Eq. 1
=
against 1/T gives the value of E∗ , whereas its intercept corresponds to
A (Arrhenius constant). The calculation of heat of reaction (ꢂH∗; Table
V) from the DTA curves was done by using the relation:
ꢂH∗ = ꢂH(muv)60 × 10−6(MJmol−1
)
(2)
TABLE V Thermodynamic Activation Parameters of Metal Complexes
E*
A
ꢂS*
ꢂH*
ꢂG*
No. Order (n) Steps (J mol−1
)
(×105s−1
)
(JK−1mol−1
)
(J mol−1
)
(kJ mol−1
)
1
2
3
4
1
1
1
1
I
II
I
II
I
II
I
II
21.18
23.22
44.37
46.02
45.83
46.86
45.82
46.75
0.27
0.26
0.27
0.18
0.19
0.20
0.22
0.20
−163.14
−157.37
−164.43
−158.54
−157.13
−158.36
−159.60
−158.55
186.93
1253.91
92.85
2000.14
263.38
2658.23
272.79
2902.64
103.15
131.92
89.93
122.21
98.94
115.37
97.76
109.06

2484
A. M. A. Alaghaz et al.
where M is the molar mass of the complex and muv = micro unit volt.
The entropy of activation (ꢂS∗) and the free energy change of activation
(ꢂG∗) were calculated using Eqs. 2 and 3:
ꢂS∗ = 2.303R[log(Ah/kT)](JK−1 mol−1
)
(3)
(4)
ꢂG∗ = ꢂH∗ − TꢂS∗(J mol−1
)
where k and h are the Boltzman and Plank constants, respectively. The
calculated values of E∗, A, ꢂS∗, ꢂH∗, and ꢂG∗ for the decomposition
steps of the complexes are appended in Table V. According to the kinetic
data obtained from the TG curves, all the complexes have negative
entropy, which indicates that the complexes are formed spontaneously.
The negative value of entropy also indicates a more ordered activated
state that may be possible through the chemisorption of oxygen and
other decomposition products. The negative values of the entropies
of activation are compensated for by the values of the enthalpies of
activation, leading to almost the same values for the free energy of
activation.28
Biological Activity
The disc diffusion method was used to measure the antimicrobial ac-
tivity of the complexes.29,30 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 III, its complexes, and traivid and tavinic (as
standard compounds) were tested against bacteria because bacteriua
can achieve resistance to antibiotics through biochemical and morpho-
logical modifications.31 The antimicrobial activity was examined with
different species of gram-positive bacteria such as Staphylococcus pyo-
genes, gram-negative bacteria such as Pseudomonas aeruguinosa and
Escherichia coli, and fungi (Candida). The data obtained are summa-
rized in Table VI. The data obtained reflect the following findings:
1) The III ligand has moderate activity in comparison with Staphylo-
coccus pyogenes and is less active in comparison with Escherichia
coli and Pseudomonas aeruguinosa. The remarkable activity of the
ligand may arise from the imino-NH and carbonitrile-C N groups,
which may play an important role in the antibacterial activity.31
2) Antibacterial activity of the complexes toward the different organ-
isms shows high to moderate activity.
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.32

Chelation of Cyclodiphosph(V)azane Complexes
2485
TABLE VI Antimicrobial Activity of III and Corresponding Metal
Complexes
Compound
(mg/mL)
S. P.
P.A.
Fungus (Candida)
E.C.
III
5
2.5
1
5
2.5
1
5
2.5
1
5
2.5
1
5
2.5
1
5
2.5
1
5
2.5
1
+ + +
++
++
+ + +
+
++
++
−
−
−
−
+
−
−
+
−
−
+
−
−
+
−
−
+
−
−
−
−
−
++
+
+
IVa
++
++
+
+ + +
++
+
+
IVb
+ + +
+ + +
++
++
++
++
+ + +
++
+
++
++
+
++
++
+
IVc
++
+
++
++
+
+
IVd
++
+
++
++
+
+
Tavenica
Traivida
+ + +
++
+
+ + +
++
+
+ + +
++
+
++
+
++
+
++
+ + +
−
−
−
aStandard materials. Inhibition value = 0.1–0.5 cm beyond control = +; Inhibition
value = 0.6–1.0 cm beyond control = ++; Inhibition value = 1.1–1.5 cm beyond control
= + + +; S.P. = Staphylococcus pyogenes; E.S. = Escherichia coli; and P.A. =
Pseudomonas aeruguinosa.
Structural Interpretation
From all of the above observations, the new ligand 1,3-di-
phenyl-2,4-bis(3-amino-9-methoxy-1-phenyl-3H-benzo[f]chromene-2-
carbonitrile)-2,2,4,4-tetrachlorocyclodiphosph(V)azane (III) forms (2M:
1L) complexes with the Co(II), Ni(II) Cu(II), and Pd(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, solid-state electrical conductivity,
magnetic moment, and spectrophotometric molar ratio and conducto-
metric methods. The design and synthesis of a new bidentate ligand
derived from 1,3-diphenyl-2,4-bis(3-amino-9-methoxy-1-phenyl-3H-
benzo[f]chromene-2-carbonitrile for use in square planar or tetrahedral
molecular templates have been successfully demonstrated. The syn-
thesis of the ligand and its complexes proved to be as straightforward

2486
A. M. A. Alaghaz et al.
SCHEME 2 Suggested structural formulae of III metal complexes.
as expected, giving high yields of the free ligand and its complexes
in simple, one-pot reactions. As anticipated, the ligand coordinates
equatorially to four-coordinate transition metal ions to give tetrahedral
(Co(II), Ni(II)) and square planar (Cu(II), Pd(II)), environments around
the metal ion anchor. The proposed general structures of the complexes
are shown in Scheme 2. III ligand always coordinates via the imino-NH
and carbonitrile-C N groups forming two-binding chelating sites.
EXPERIMENTAL
All chemicals used were of analytical reagent grade. They in-
cluded CoCl2.6H2O, NiCl2.6H2O, CuCl2.2H2O, and Pd(NO3)2. 2H2O
and phosphorus pentachloride supplied from BDH. The solvents
used were of analytical grade and were purified by standard

Chelation of Cyclodiphosph(V)azane Complexes
2487
methods. The preparation of 3-amino-9-methoxy-1-phenyl-3H-benzo[f]-
chromene-2-carbonitrile (II) was carried out according to the method
in the literature.33 1,3-Diphenyl-2,2,2,4,4,4,-hexachlorocyclodiphosph-
(V)azane (I) was prepared and purified using the method previously
reported.1,2
Synthesis of Ligand
The solid of 3-amino-9-methoxy-1-tolyl-3H-benzo[f]chromene-2-carbo-
nitrile (II) (3.28 g, 0.01 mmol) was added in small portions to a
well-stirred solution of the 1,3-diphenyl-2,2,4,4-tetrachlorocyclo-
diphosph(V)azane (I) (3.79 g, 0.005 mmol) in acetonitrile (100 mL) over
30 min. 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 (yellow) was filtered, washed several times with acetoni-
trile, and dried in vacuo to give the corresponding 1,3-diphenyl-2,4-
bis(3-amino-9-methoxy-1-tolyl-3H-benzo[f]chromene-2-carbonitrile)-
2,2,4,4-tetrachlorocyclodiphosph(V)azane (III) (Scheme 1). Yield
90.0%, 1H-NMR (300MHz; DMSO-d6): 7.28–7.56 (32H, m, J = 8.1
Hz, Ar-H); 3.90 (6H s, J = 4.7 Hz, 2OMe); 8.97 (2H br, s, NH).
13C-NMR (300MHz; DMSO-d6): 154.11, 152.26, 151.30, 149.14, 148.31,
147.37, 146.53, 145.26, 144.32, 142.44, 141.37, 140.41, 137.83, 137.34,
136.99, 13.82, 129.63, 129.26, 128.97, 127.93, 127.76, 126.63, 122.52,
118.38 (all aromatic C) 158.27, 156.87 (2C N). 31P-NMR (365 MHz;
DMSO-d6): 25.4 (phosphazo ring).
Synthesis of Complexes
A hot solution (60◦C) of the metal salts (CoCl2 .4H2O [0.4 g; 0.002
mol]), (NiCl2.4H2O [0.41 g; 0.002 mol]), (CuCl2.2H2O [0.33 g; 0.002
mol]) or (Pd(NO3)2.2H2O [0.43 g; 0.002 mol]) in acetonitrile (50
mL) was added drop-wise to a hot solution of 1,3-diphenyl-2,4-
bis(3-amino-9-methoxy-1-tolyl-3H-benzo[f]chromene-2-carbonitrile)-
2,2,4,4-tetrachlorocyclodiphosph(V)azane (III) (0.658 g; 0.001 mol) in
acetonitrile (100 mL) in a 2:1 metal-to-ligand molar ratio at room
temperature with continuous stirring. After complete addition of the
hot metal-salt solution, the reaction mixture was heated under reflux
for about 2 h under dry conditions. The complexes obtained were
washed with acetonitrile and then with dry diethyl ether and dried in
vacuo.

2488
A. M. A. Alaghaz et al.
Apparatus and Experimental Conditions
Elemental Analysis and Metal Percentage
Elemental analyses (C, H, N, Cl, and S) were performed using a
Perkin-Elmer CHN 2400 elemental analyzer. Percentages of the metal
ions of the complexes were determined using PYEUNICAM SP 1900
atomic absorption spectrophotometer supplied with the corresponding
lamp used for this purpose. The phosphorus content was determined
gravimetrically as phosphoammonium molybdate.34
IR Spectra
The KBr infrared spectra were recorded on Perkin-Elmer 1430 IR
spectrophotometer covering the frequency range 200–4000 cm−1. Cali-
bration of the frequency readings was made with polystyrene film.
UV-Vis Spectra
The spectral studies were measured using a PYE-Unicam spec-
trophotometer model 1750 covering the wavelength range 190–900 mm.
The complexes were measured in nujol mull following the method de-
scribed by Lee et al.35
1H, 13C, and 31PNMR Spectra
1H and 13C NMR spectra were recorded in (CD3)2SO on a Varian
Gemini 200 MHz or on a Varian Mercury 300 MHz Em-360-60 MHz
spectrometer at Cairo University and shifts were expressed in δ units
using TMS as internal reference. 31P NMR spectra were run, relative to
external H3PO4 (85%), with a Varian FT-80 spectrometer at 36.5 MHz.
Magnetic Susceptibility Measurements
Molar magnetic susceptibility corrected for diamagnetic using Pas-
cal’s constant was determined at room temperature (298 K) using Fara-
day’s method. The apparatus was calibrated with Hg [Co(SCN)4].36
X-Ray Powder Diffraction
The X-ray powder diffraction analyses were carried out by using
Rigku Model ROTAFLEX Ru-200. Radiation was provided by copper
target (Cu anode 2000 W) high-intensity X-ray tube operated at 40
kV and 35 MA. Divergence slit and the receiving slit were 1 and 0.1,
respectively.
Electrical Conductivity
Conductivity measurements were made on discs having 1 mm thick-
ness of 1,3-diphenyl-2,4-bis(3-amino-9-methoxy-1-tolyl-3H-benzo[f]

Chelation of Cyclodiphosph(V)azane Complexes
2489
chromene-2-carbonitrile)-2,2,4,4-tetrachlorocyclodiphosph(V)azane
(III) and its complexes sandwiched between two copper electrodes. The
conductivity cell used was the same as that reported in the literature.37
The electrical conductivity was measured in the temperature range
30–150◦C. The activation energies were calculated using the equation
σ = σ◦ exp (−E/2 kT).
Thermal Analysis
Thermogravimetric analysis was performed under a nitrogen atmo-
sphere using a Shimadzu TGA-50H with a flow rate of 20 mL min−1
.
ESR Spectra
ESR spectra were recorded at 100 kHz modulation and 10 G mod-
ulation amplitude on a Varian E-9 Spectrophotometer. Incident power
of 10 mV was used and resonance conditions were at ca 9.75 GHz
(X-band) at room temperature. Spectra were obtained with an air prod-
ucts LTD-3-110 Heli-Trans liquid helium transfer refrigerator. The field
was calibrated with a powder sample of 2,2-diphenyl pyridylhydrazone
(DPPH) g = 2.0037.38
Antimicrobial Activity
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 a diffu-
sion agar technique.
REFERENCES
[1] A. M. A. Alaghaz and M. M. El-Desoky, Al-Azhar Bull. Sci., 17, 1 (2006).
[2] A. M. A. Alaghaz and S. A. H. Elbohy, Phosphorus, Sulfur, and Silicon, 183, 2012–
2031 (2008).
[3] E. H. M. Ibrahim, I. M. Abd-Ellah, L. S. Showki, and I. Alaimi, Phosphorus, Sulfur,
and Silicon, 33, 109 (1987).
[4] A. M. A. Alaghaz, PhD thesis, Faculty of Science, Al-Azhar University (Boys), Cairo,
Egypt, 2004.
[5] A. N. Al-Khazandar, R. S. Farag, and I. M. Abd-Ellah, Proc. Indian Natl. Sci. Acad.,
60A, 793 (1994).
[6] I. M. Abd-Ellah, E. H. M. Ibrahim, and A. N. Al-Khazandar, Phosphorus, Sulfur,
and Silicon, 13, 13 (1987).
[7] I. M. Abd-Ellah, Y. Al-Shaibi, A. A. Ba-issa, and M. S. El-Hammadi, Phosphorus,
Sulfur, and Silicon, 139, 29 (1998).
[8] J. V. Pustinger, W. T. Cove, and M. L. Neilsen, Spectrochim. Acta, 15, 909 (1959).
[9] D. E. C. Corbridge, J. Appl. Chem., 6, 456 (1956).
[10] L. C. Thomas and R. A. Chittenden, Chem. Ind. London, 18, 1913 (1961).
[11] A. M. A. Alaghaz and H. A. Gumaa, Al-Azhar Bull. Sci., 17, 73 (2006).
[12] R. B. Harvey and J. E. Mayhood, Can. J. Chem., 33, 1552 (1955).

2490
A. M. A. Alaghaz et al.
[13] L. C. Scheinman, Introduction to Spectroscopic Methods for the Identification of
Organic Compounds, 1st ed. (Elsevier, London, 1970) p. 173.
[14] J. H. Aupers, Z. H. Chohan, N. M. Comerlato, R. A. Howi, A. C. Silvino, J. L. Wardell,
and S. M. S. V. Wardell, Polyhedron, 21, 2107 (2002).
[15] S. E. Wiberley, S. C. Bunce, and W. H. Bauer, Anal. Chem., 32, 217 (1960).
[16] M. Becke-Goehring and B. Z. Bopple, Anorg. Chem., 322, 239 (1963).
[17] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Com-
pounds (Wiley, New York, 1978).
[18] G. J. Kleywegt, W. G. R. Wiesmeijer, G. J. V. Driel, W. L. Driessen, J. Reedijk, and J.
H. Noordik, J. Chem. Soc., Dalton Trans., 2177 (1985).
[19] I. M. Abd-Ellah, B. A. El-Sayed, M. A. El-Nawawy, and A. M. A. Alaghaz, Phospho-
rus, Sulfur, and Silicon, 177, 2895 (2002).
[20] K. I. Goldberg, J. V. Martinez, G. E. Perez, L. A. Ackerman, and D. X. West, Polyhe-
dron, 18, 1177 (1999).
[21] N. F. Mott, and E. A. Davis, Electronic Processes in Non-Crystalline Materials
(Clarendon Press, Oxford, 1971).
[22] D. F. Shriver, P. W. Atkins, and C. H. Langford, Inorganic Chemistry (Oxford Uni-
versity, Oxford, 1996).
[23] D.A. Seanor, Electrical Properties of Polymers (Academic Press, New York, 1982).
[24] B. D. Cullity, Elements of X-ray Diffraction, 2nd ed. (Addison-Wesley, New York,
1993).
[25] A. Bencini and D. Gattechi, EPR of Exchange Coupled Systems (Springer-Verlag,
Berlin, 1990).
[26] B. K. Singh, R. K. Sharma, and B. S. Garg, J. Therm. Anal. Catal., 84, 593 (2006).
[27] A. W. Coats and J. P. Redfern, Nature, 68, 201 (1964).
[28] B. K. Singh, R. K. Sharma, and B. S. Garg, Spectrochim. Acta A, 63, 96 (2006).
[29] M. A. Ibrahim, A. A. H. Ali, and F. M. Maher, J. Chem. Tech. Biotechnol., 55, 217
(1992).
[30] I. M. Abd-Ellah, M. E. Hussein, A. N. El-Khazandar, and R. S. Farag, Orient. Chem.,
7, 121 (1991).
[31] A. S. A. Zidan, Phosphorus, Sulfur, and Silicon, 178, 567 (2003).
[32] A. Chaudhary and R. V. Singh, Phosphorus, Sulfur, and Silicon, 178, 603 (2003).
[33] A. M. El-Agrody, F. A. Eid, H. A. Emam, H. M. Mohamed, and A. H. Bedair, Z.
Naturforsch., 57b, 579–585 (2002).
[34] R. Voy, Chem. Ztg. Chem. Apparatus, 21, 441 (1897).
[35] P. H. Lee, E. Griswold, and J. Kleinberg, Inorg. Chem., 3, 1278 (1964).
[36] N. B. Figgs and J. Lewis, Modern Coordination Chemistry (Interscience, New York,
1967), p. 403.
[37] M. A. Ahmed and F. A. Radwan, J. Phys. Chem. Solid., 49, 1385 (1988).
[38] D. Reinen and G. Friebel, Inorg. Chem., 23, 791 (1984).