Structure and properties characteristic of dimeric silver(I) complex: Dinuclear Bis(O,O′-diphenyldithiophosphato)bis(1,10-phenanthroline) Ag(I)

Article abstract of DOI:10.1023/B:RUCO.0000047467.29853.07

The complex bis(O,O′-diphenyldithiophosphato)bis(1,10-phenanthroline) silver(I), Ag₂[(PhO)₂PS₂]₂(Phen) ₂, has been synthesized and structurally characterized. Its crystal structure has been determined by X-ray crystallography. It crystallizes in the monoclinic system, space group P2₁/c, with unit cell parameters a = 11.140(2) A, b = 10.044(2) A, c = 23.006(6) A, β = 113.36(3)°; V = 2363.1(9) A³, ρ_calcd = 1.600 g/cm³, and Z = 4 for R₁ = 0.0961. The coordination geometry of each Ag atom, by two N atoms from 1,10-phenanthroline ligand and by two S atoms from two O,O′-diphenyldithio phosphate anions, is that of a tetrahedron. The two diphenyldithiophosphato ligands each bridge two silver atoms to form an eight-membered Ag₂S₄P₂ ring, while the 1,10-phenanthroline molecule coordinates to a silver atom to complete the local tetrahedral geometry. The Ag...Ag separation is 3.185(2) A. The data of elemental analysis, IR and UV-vis spectroscopies are in good agreement with the crystal structure. The thermal gravimetry data indicate that there are two decomposition steps with one intense endothermical peak and one weak exothermical peak. The final product of the thermal decomposition is AgS.

Full text of DOI:10.1023/B:RUCO.0000047467.29853.07

Russian Journal of Coordination Chemistry, Vol. 30, No. 11, 2004, pp. 800–804. From Koordinatsionnaya Khimiya, Vol. 30, No. 11, 2004, pp. 849–853.
Original English Text Copyright © 2004 by Jian, Zheng, Xiao.
Structure and Properties Characteristic
of Dimeric Silver(I) Complex: Dinuclear
Bis(O,O'-Diphenyldithiophosphato)bis(1,10-phenanthroline) Ag(I)*
F. F. Jian, G. X. Zheng, and H. L. Xiao
New Materials & Function Coordination Chemistry Laboratory, Qingdao University of Science and Technology,
Qingdao, 266042 P. R. China
e-mail: ffj2001@public.qd.sd.cn
Received July 19, 2003
Abstract—The
complex
bis(O,O'-diphenyldithiophosphato)bis(1,10-phenanthroline)
silver(I),
Ag2[(PhO)2PS2]2(Phen)2, has been synthesized and structurally characterized. Its crystal structure has been
determined by X-ray crystallography. It crystallizes in the monoclinic system, space group P21/c, with unit cell
parameters a = 11.140(2) Å, b = 10.044(2) Å, c = 23.006(6) Å, β = 113.36(3)°; V = 2363.1(9) Å3, ρcalcd
=
1.600 g/cm3, and Z = 4 for R1 = 0.0961. The coordination geometry of eachAg atom, by two N atoms from 1,10-
phenanthroline ligand and by two S atoms from two O,O'-diphenyldithio phosphate anions, is that of a tetrahe-
dron. The two diphenyldithiophosphato ligands each bridge two silver atoms to form an eight-membered
Ag2S4P2 ring, while the 1,10-phenanthroline molecule coordinates to a silver atom to complete the local tetra-
hedral geometry. The Ag···Ag separation is 3.185(2) Å. The data of elemental analysis, IR and UV-vis spec-
troscopies are in good agreement with the crystal structure. The thermal gravimetry data indicate that there are
two decomposition steps with one intense endothermical peak and one weak exothermical peak. The final prod-
uct of the thermal decomposition is AgS.
Dialkyldithiophosphate complexes of transition
metals have received increasing attention in recent
years owing to their extensive applications in lubrica-
tion engineering and in the plastics industry [1, 2]. In
addition to their syntheses and various physicochemi-
cal investigations, the crystal structures of many of
these compounds and their adducts with nitrogen-con-
taining bases have been reported [3, 4]. Metal chelates
in which the metal ion is coordinately unsaturated can
act as electron acceptors and yield adducts with the
neutral molecules being electron donors [5]. Adducts
and their formation reactions have also been found use-
ful in a wide variety of ways. The amines in lubricating
oil have a great influence on the properties of metal
dialkyldithiophosphate additives [6]. It is interesting to
investigate further the interaction between metal
dialkyldithiophosphate and amines. In this paper, we
report the synthesis and crystal structure of the title
compound. The elemental analysis, IR, electronic
absorption spectra, and thermal gravimetry (TG) have
also been investigated.
Ag[(RO)2PS2] (I). Stoichiometric amounts of sil-
ver(I) nitrate and sodium O,O'-dialkyldithiophosphate
in deionized water were stirred together for 20 min. The
brown precipitate was collected by filtering, washed
with water, and then dried over P4O10. The complexes
were collected and submitted for elemental analysis.
Yield (90–95%).
For C12H10O2PS2Ag (R = Ph)
anal. calcd (%):
Found (%):
C, 37.04;
C, 36.82;
H, 2.59.
H, 2.67.
Ag2[(PhO)2PS2]4(Phen)2 (II). The silver(I) diphen-
yldithiophosphate complexes (0.78 g, 2.0 mmol) were
dissolved in hot ethanol (50 ml), a slight excess of 1,10-
phenanthroline (0.38 g, 2.1 mmol) was added, and the
resulting solution was refluxed for 4–5 h. The colorless
mixture was cooled to room temperature, then filtered
off, and the filtrate was left to stand undisturbed. Upon
slow evaporation at room temperature, the colorless
crystalline solid II appeared several days later and was
separated by filtration. The C, H, and N contents were
determined by elemental analysis. The yield of
Ag2[(PhO)2PS2]4(Phen)2 was 1.01 g (87%).
EXPERIMENTAL
All chemicals used were of analytical or reagent
grade and used directly without further purification.
Na[(RO)2PS2] (R = Ph, PhCH2, Et, Pr, et al.) was pre-
pared according to literature method [7].
For C48H36N4O4P2S4Ag2
anal. calcd (%):
Found (%):
C, 50.63;
C, 50.15;
H, 3.19;
H, 3.06;
N, 4.92.
N, 4.43.
*This article was submitted by the authors in English.
1070-3284/04/3011-0800 © 2004 åÄIä “Nauka /Interperiodica”

STRUCTURE AND PROPERTIES CHARACTERISTIC OF DIMERIC SILVER(I) COMPLEX
801
Table 1. Crystal data and summary of collection and refine- Table 2. Selected bond lengths (d) and bond angles (ω) in
ment for the structure II
the structure II
Formula
M
C24H18AgN2O2PS2
569.36
Bond
d, Å
Bond
d, Å
Ag(1)–N(1)
2.338(10)
Ag(1)–S(1)
S(2)–P(1)
2.482(3)
1.944(5)
2.443(8)
1.963(4)
1.339(17)
Crystal system
Space group
a, Å
Monoclinic
P21/c
Ag(1)–Ag(1A)* 3.185(2)
O(1A)–C(1)
Ag(1)–S(2A)
P(1)–O(1A)
1.47(2)
Ag(1)–N(2)
S(1)–P(1)
11.140(2)
10.044(2)
23.006(6)
113.36(3)
2363.1(9)
4
2.705(3)
1.587(18)
b, Å
N(1)–C(13)
c, Å
Angle
ω, deg
Angle
ω, deg
β, deg
V, Å3
N(1)Ag(1)N(2)
68.5(3) N(2)Ag(1)S(1)
120.2(2)
N(2)Ag(1)S(2A) 88.9(3) N(1)Ag(1)Ag(1A) 114.2(2)
S(1)Ag(1)Ag(1A) 65.91(9) O(1A)P(1)O(2) 109.4(9)
N(2)Ag(1)S(1) 120.2(2) N(1)Ag(1)S(2A) 130.9(3)
S(1)Ag(1)S(2A) 106.2(1) N(2)Ag(1)Ag(1A) 171.4(2)
O(2)P(1)S(2) 111.3(3)
Z
ρ
calc, g/cm3
1.600
µ, mm–1
1.121
F(000)
1144
θ ranges, deg
Interval of reflection indices
1.93 to 24.98
* Symmetric transformation for atoms with index A: –x, –y, –z + 1.
0 ≤ h ≤ 13, –11 ≤ k ≤ 0,
–27 ≤ l ≤ 25
Reflections collected
Data/restraints/parameters
GOOF
4344/4117 (Rint = 0.0302)
4117/0/290
nique used was ω-scan. Intensities were corrected for
Lorentz and polarization effects and empirical absorp-
tion, and the data reduction using SADABS [8] pro-
gram.
1.346
Final R indices (I > 2σ(I))
R indices (all data)
R1 = 0.0961, wR2 = 0.2885*
R1 = 0.1385, wR2 = 0.3461*
1.362 and –2.329
The structure of II was solved by direct method and
refined by least squares on F2obs by using the
SHELXTL [9] software package. All nonhydrogen
atoms were anisotropically refined. The hydrogen
atoms were located by difference synthesis and refined
isotropically. The molecular graphics were plotted
using SHELXTL [9]. Atomic scattering factors and
anomalous dispersion corrections were taken from
International Tables for X-ray Crystallography [10]. A
summary of the key crystallographic information is
given in Table 1.
Largest difference peak and
hole/e Å–3
2
2
2
2
2
* w = 1/[σ (F ) + (0.0512P) + 0.0000P], where P = (F + 2Fc )/3.
Elemental analysis for carbon, hydrogen and nitro-
gen was performed on a Perkin-Elmer 240 C analysis
instrument. IR spectra were recorded in the range of
4000–300 cm–1 on a Perkin-Elmer 467 spectrometer
using KBr pellets. Electron absorption spectra in solu-
tion were recorded on a Shimadzu UV-240 spectropho-
tometer. Thermal gravity and differential thermal anal-
ysis (DTA) were recorded on an SDT 2980 simulta-
neously for the samples of ca. 10 mg under a nitrogen
atmosphere (150 ml/min) at a heating rate of 20 K/min.
RESULTS AND DISCUSSIONS
The molecular structure of the II illustrated in
Figs. 1 and 2 shows a perspective view of the crystal
packing in the unit cell. Selected bond distances and
angles of the II are listed in Table 2.
X-ray diffraction analysis. Single crystals of the II
The molecular structure of the compound II consists
were grown from the ethanol solution by evaporating of discrete molecules of Ag2[(PhO)2PS2]4(Phen)2. It is
the solvent slowly at room temperature. The experi- built up of centrosymmeric dimeric entities. The coor-
mental diffraction arrays were collected on Enraf-Non- dination sphere of the silver(I) ion is best described as
ius CAD4 automated diffractometer. Reflection data a distorted tetrahedral geometry. The two diphen-
and reflections for the unit cell determination were yldithiophosphato ligands each bridge two silver atoms
measured at 20°C using MoKα radiation (λ = to form an eight-membered Ag2S4P2 ring, while two
0.71073 Å) with a graphite monochromator. The tech- 1,10-phenanthroline molecules coordinate to a silver
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 30 No. 11 2004

802
JIAN et al.
C(3A)
C(4)
N(2A)
C(3B)
N(1A)
C(2A)
C(1)
O(1A)
C(5)
C(6)
C(2B)
Ag(1A)
O(2A)
S(2)
S(1A)
O(1BA)
O(1B)
P(1A)
P(1)
S(2A)
O(1AA)
C(1A)
S(1)
O(2)
C(6A)
C(5A)
Ag(1)
C(11)
C(10)
C(13)
C(2BA)
C(9)
N(2)
N(1)
C(2AA)
C(3AA)
C(22)
C(21)
C(3BA)
C(15)
C(20)
C(24)
C(23)
Fig. 1. The molecular structure of Ag [(PhO) PS ] (Phen) showing the atom labeling scheme. Atoms are represented as thermal
2
2
2 4
2
ellipsoids at 50% level.
atom to form a five-membered chelate ring. The Ag–N 3.185(2) Å, which is in the range 2.93 to 3.52 Å, show-
bond lengths (2.338(10) and 2.443(8) Å) are compara- ing that no significant silver–silver interactions exist in
ble with those of 2.332(2), 2.342(2) and 2.419(2), Å the compound [5].
found in other silver(I) complexes with tetrahedral
In the II, there are some π–π stacking interactions in
coordination [11–13]. There are one longer Ag–S bond
the lattice [16, 17]. The shortest center-to-center dis-
(2.705(3) Å) and one shorter ones (2.482(3) Å) in the
tances between the adjacent moieties are 3.469 Å. It is
II, which are obvious difference with the Ag–S bonds
obvious that they form the slightly stronger π–π stack-
of other similar tetrahedral structure (2.507–2.644 Å)
ing interaction [18]. In the solid state, all above exten-
[5, 14]. It is apparent that the steric and electronic
sive hydrogen bonds stabilize the crystal structure.
effects of the phenyl group can destabilize the Ag–S
The electronic absorption spectrum of the II in
EtOH exhibits three intense bands at 200.0, 230.0, and
265.1 nm in the UV range. These bands belong to π–π*
or n–π* orbital transitions of the phenanthroline
ligands [19]. There are no d–d bands in the UV spec-
trum. The IR spectrum exhibits characteristic strong
bands at 1590 (C=C), 1487, 1423 (C=N), and 845 cm–1
(ν(C–H) benzene ring) and 731 cm–1 (ν(C–H) pyridine
ring) for the coordinated phenanthroline ligands [20].
The significant change in the ligand bands upon com-
plexation is the decrease in ν(C–Npy). The shift to low
bond. It is possible to interpret these results on the basis
of a simple electrostatic model. The π conjugated sys-
tem between O atom and phenyl ring reduces the net
positive charge on the O atom and increases the net neg-
ative charge on the S atoms. The latter effect results in
an increase in the SPS angle (119.8(2)°) while the
former effect lengthens the Ag–S distance and
decreases the SAgS angle (106.16(13)°). There are
some disorder at O(1), C(2), and C(3) atoms, with the
occupation ratios of 60, 50, and 60%, respectively.
The P–S bond lengths and SPS angles in the II are frequencies in the spectra of the complexes suggests
normal [15]. The phenanthroline ligand with Ag atoms delocalization of the π-election density around the
is coplanar. The average C–C distances in the phenan- nitrogen atoms and a lower C=N stretching force due to
throline rings are approximately the expected mean the coordination through nitrogen atom of the pyridine
value of 1.40 Å. The Ag···Ag separation in the dimer is ring (for the free phenanthroline ligand, ν(C=N) at
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 30 No. 11 2004

STRUCTURE AND PROPERTIES CHARACTERISTIC OF DIMERIC SILVER(I) COMPLEX
803
x
0
z
Fig. 2. A view of the crystal packing down the x axis for Ag [(PhO) PS ] (Phen) .
2
2
2 4
2
1515 and 1452 cm–1) [21]. The IR spectra of the II also decreases and the weight loses. When the temperature
exhibit
the
characteristic
absorptions
of
is over 455°C, Ag2S4P2 decomposes. The weight loss of
8.49 wt % suggests that the residue may be AgS (found
73.20 wt %; calcd. 75.41 wt %). Meanwhile, no struc-
Ag[(PhO)2PS2]: ν(P−OPh) at 1189 s, 908 s, and 883 s, br
and νas(PS2) at 771 s and 731 s, as well as νs(PS2) at 578
m and 539 s cm–1, respectively [22]. There are some
bands at 2852–3058 cm–1. It may be assigned to the C–
H stretching vibrations of the phenyl ring. The strong
bands at 1509 s, 1453 s (νC–C phenyl ring) and 684 s cm–1
(νC–H phenyl ring) are also assigned to the phenyl ring.
TG, %
DTG, %/min
100
The TG/DTG curves of the II are presented in
Fig. 3. Thermogravimetric analysis (TGA) of the II
reveals that the decomposition events mainly take place
at about 210 and 445°C, respectively. There are one
intense heat-absorption peak at 302.6°C and one weak
heat-releasing peak at 445°C. It shows no decomposi-
tion before 210°C, but at 210°C, decomposition occurs.
At 375°C, the weight loss of 64.26 wt % suggests that
the residue may be Ag2S4P2 (eight-membered Ag2S4P2
ring core) (calcd 64.34 wt %). Between 436.7 and
453.4°C, there is about 1.78 wt % weight addition,
which is ascribed to the absorption of Ag2S4P2. In this
process, Ag2S4P2 will adsorb gas and the weight will
increase [23]. This phenomenon also appears in the
process of thermal decomposition of other dialkyl-
dithiocarbamate metal complexes [24]. With the tem-
perature increasing, the absorption of Ag2S4P2
0
90
80
70
60
50
40
30
–5
64.26%
–10
–15
–20
8.49%
DTG: 302.6°C
100 200 300 400 500 600 700 800
T, °C
Fig. 3. TG/DTG curves of the compound II.
RUSSIAN JOURNAL OF COORDINATION CHEMISTRY Vol. 30 No. 11 2004

804
JIAN et al.
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high thermal stability.
11. Fu, Y.J., Yang, H., Wang, D.F., et al., Polyhedron, 1997,
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