Syntheses, crystal structures and characterization of divalent transition metal sulfonate complexes with o-phenanthroline

Article abstract of DOI:10.1016/S0022-2860(03)00428-9

Three new complexes, namely [Cu(phen)(L)(H₂O) ₂]L·H₂O 1, [M(phen)₂(H ₂O)₂]₂L·6H₂O [M = Co(2), Ni(3)], where, HL = 4-methylbenzenesulfonic acid and phen = o-phenanthrol

Full text of DOI:10.1016/S0022-2860(03)00428-9

Journal of Molecular Structure 657 (2003) 333–341
www.elsevier.com/locate/molstruc
Syntheses, crystal structures and characterization of divalent
transition metal sulfonate complexes with o-phenanthroline
*
Jin Yang, Jian-Fang Ma , Dong-Mei Wu, Li-Ping Guo, Jing-Fu Liu
Department of Chemistry, Northeast Normal University, No. 138, Renmin Street, Changchun 130024, People’s Republic of China
Received 2 March 2003; revised 17 June 2003; accepted 26 June 2003
Abstract
Three new complexes, namely [Cu(phen)(L)(H2O)2]L·H2O 1, [M(phen)2(H2O)2]2L·6H2O [M ¼ Co(2), Ni(3)], where,
HL ¼ 4-methylbenzenesulfonic acid and phen ¼ o-phenanthroline, have been synthesized. The crystal structures were
determined by X-ray diffraction method and refined by full-matrix least-squares methods to R ¼ 0:0535 and wR ¼ 0:1492
using 3567 reflections with I . 2sðIÞ for 1; R ¼ 0:0388 and wR ¼ 0:1223 using 3844 reflections with I . 2sðIÞ for 2; and
R ¼ 0:0401 and wR ¼ 0:1222 using 3425 reflections with I . 2sðIÞ for 3. 1 Consists of cationic species [Cu(phen)(L)(H2-
O)2]þ, in which Cu(II) ion is five-coordinated by two nitrogen atoms of o-phenanthroline, two water molecules and one
sulfonate oxygen atom. The cations and the non-coordinating sulfonate anions are linked by hydrogen bonds to form
infinite chains. Complexes 2 and 3 are isostructral compounds. Each of them consists of cationic species [M(phen)2(-
H2O)2]2þ, in which metal ion is six-coordinated by four nitrogen atoms from two o-phenanthroline molecules and two
water oxygen atoms. The sulfonate ions do not coordinate to metal ion. The cations, non-coordinating sulfonate ions and
lattice water molecules are linked by hydrogen bonds to form infinite zigzag chains. CV, FT-IR, UV–Vis and TGA were
also used to characterize these compounds.
q 2003 Elsevier B.V. All rights reserved.
Keywords: Crystal structure; Cyclic voltammetry; FT-IR; TGA; UV–Vis
1. Introduction
and catalysis [4]. But the coordination chemistry of
transition metal sulfonates is not well explored and/
or rationalized [5], owing to the preconception that
they are weakly coordinating ligands. Several
studies on the coordination chemistry of transition
metal sulfonates and their solid-state properties have
been reported. In some cases, sulfonate group can
compete with water molecule and coordinate to
metal ion [6]. Complexes where, sulfonate ions
coordinate as monodentate [7], bidentate and
tridentate [8] ligands have been reported. It is
found that the coordination behavior of metal cation
It is well known that the area of metal
phosphonate chemistry has been developed rapidly.
A lot of new compounds have been synthesized and
characterized. The interest stems from a broad range
of applications, such as in the areas of sorption and
ion exchange [1], sensors [2], non-linear optics [3],
*
Corresponding author. Tel.: þ86-431-5268620; fax: þ86-431-
5684009.
E-mail address: jfma@public.cc.jl.cn (J.-F. Ma).
0022-2860/03/$ - see front matter q 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-2860(03)00428-9

334
J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
toward RSO23 can be tailored chemically by
introducing other ligand [9]. So far several struc-
tures of metal 4-methylbenzenesulfonates have been
studied [10]. To the best of our knowledge, no
crystal structure and characterization of the tran-
sition metal 4-methylbenzenesulfonate complexes
with o-phenanthroline have been reported. In this
paper these complexes have been synthesized, and
their coordination modes, IR, UV–Vis, TGA and
electrochemistry were studied in detail.
2.2. Crystal structure determination and physical
measurements
Experimental details of the X-ray analyses are
provided in Table 1. Diffraction intensities for the
compound 1 were collected on a Siemens P4
diffractometer using the v scan technique. Lorentz
polarization and absorption corrections were
applied [11]. Diffraction intensities for the com-
pounds 2 and 3 were collected on a Rigaku
RAXIS-RAPID image plate diffractometer using v
scan technique with Mo Ka radiation ðl ¼
ꢀ
2. Experimental
0:71069 AÞ: Absorption corrections were applied
using multi-scan technique [12]. The structures
were solved with the direct method of SHELXS-97
[13] and refined with full-matrix least-squares
techniques using the SHELXL-97 program [14]
within WINGX [15]. Non-hydrogen atoms were
refined anisotropically. The hydrogen atoms on
carbon atoms were generated geometrically, while
the aqua hydrogen atoms were not located.
Analytical expression of neutral-atom scattering
factors were employed, and anomalous dispersion
corrections incorporated [16]. Drawings were pro-
duced with SHELXTL-PLUS [17].
2.1. Synthesis
[Cu(phen)(L)(H2O)2]L·H2O 1. 4-Methylbenzene-
sulfonic acid (0.380 g, 2 mmol) was added with
constant stirring to an suspension of Cu(OH)2
(1 mmol) in 10 ml of water. Then o-phenanthroline
(0.198 g, 1 mmol) was added to the solution with
stirring. Blue crystals of complex 1 were obtained
from the solution after standing at room temperature
for several days (yield 73%). Calc. for C26H28N2O9-
S2Cu: C, 48.78; H, 4.41; N, 4.38. Found: C, 48.81; H,
4.26; N, 4.53%.
The FT-IR spectrum was recorded from KBr
pellets in range 4000–400 cm21 on a Mattson
Alpha-Centauri spectrometer. UV–Vis spectrum
was recorded on a 756 MC spectrophotometer.
TGA was performed using a Perkin–Elmer TG-7
analyzer in nitrogen. In cyclic voltammetry (CV),
electrochemical measurements were performed using
a three-electrode cell at room temperature. A glass
carbon (GC) working (3 mm in diameter) and a Pt
wire counter electrode were employed. The reference
electrode is Ag/AgCl (satd). The surface of GC
electrode was polished with 0.1 mm a-alumina
applied to a gray billiard cloth and washed with
distilled water many times. CV data were collected
with LK98B Electrochemical Analyzer (Changchun
Institute of Applied Chemistry) coupled to a HP-55
Computer. Tetrabutylammonium perchlorate
(TBAP) used as an electrolyte for electrochemical
measurements was recrystallized from absolute
ethanol, and dried two days in a vacuum oven
before used. Doubly distilled water was used
throughout. Other reagents employed are of analyti-
cal grade.
[Co(phen)2(H2O)2]2L·6H2O 2. 4-Methylbenzene-
sulfonic acid (0.380 g, 2 mmol) was added with
constant stirring to a suspension of CoCO3
(0.228 g, 1 mmol) in 10 ml of water. Then o-
phenanthroline (0.198 g, 1 mmol) was added to the
solution with stirring. Orange crystals of complex 2
were obtained from the solution after standing at
room temperature for several days (68% yield
based on Co). Calc. for C38H46N4O14S2Co: C,
50.39; H, 5.12; N, 6.19. Found: C, 50.63; H, 4.98;
N, 6.33%.
[Ni(phen)2(H2O)2]2L·6H2O 3. 4-Methylbenzene-
sulfonic acid (0.380 g, 2 mmol) was added with
constant stirring to a suspension of NiCO3 (0.227 g,
1 mmol) in 10 ml of water. Then o-phenanthroline
(0.198 g, 1 mmol) was added to the solution with
stirring. The solids were filtrated and dried in air.
Recrystallization of the product from a mixture of
ethanol and water gave blue crystals of 3 (47%
yield based on Ni). Calc. for C38H46N4O14S2Ni: C,
50.40; H, 5.12; N, 6.19. Found: C, 50.67; H, 5.01;
N, 6.43%.

J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
335
Table 1
Crystal data for compounds 1–3
1
2
3
Formula
C
26H28CuN2O9S2
C38H46CoN4O14S2
905.84
Monoclinic
C2=c
C38H46NiN4O14S2
905.62
Monoclinic
C2=c
Formula weight
Crystal system
Space group
640.16
Triclinic
ꢁ
P1
˚
a (A)
˚
b (A)
˚
c (A)
10.361(3)
11.690(3)
12.393(5)
77.46(3)
72.34(3)
75.04(3)
1366.0(8)
2
21.314(4)
16.493(3)
14.285(3)
90
21.308(4)
16.451(3)
14.469(3)
90
a (8)
b (8)
g (8)
122.55(3)
90
122.27(3)
90
3
˚
V (A )
4232.8(15)
4
4288.6(15)
4
Z
Dc (gcm23
)
1.566
1.421
1.403
Fð000Þ
662
1892
1896
m (mm21)
1.009
0.574
0.619
Reflections collected
Unique reflections
Observed reflections
5841
9122
9400
4792
4850
4898
3567
3844
3425
ðI . 2sðIÞÞ
R1ðI . 2sðIÞÞ
wR2ðI . 2sðIÞÞ
0.0535
0.1492
0.0388
0.1223
0.0401
0.1222
3. Results and discussion
regions, respectively. The peaks of nas(SO3) for
compound 1 are clearly different from those in 2 and
3. The splitting of peaks for nas(SO3) occurs in 1 (see
Table 2). From the splitting of peaks the coordination
3.1. Characterization
The main IR bands of the compounds 1–3 with
their group assignments are listed in Table 2. The
clearly visible bands at 853–721 cm21 are attributed
to out-of-plane CZH deformations of phen and L2
ligands [18]. The vibration frequencies of phen are
shifted after coordination [19], the peak at 1605 cm21
corresponding to n (CvN) shifts to 1585 cm21 upon
coordination, while the phen n (CvC) frequency of
1500 cm21 is shifted to about 1518 cm21 [20,21].
Peaks at about 430 cm21 are attributed to the M–N
stretching vibration [22]. The coordination of the phen
is also indicated by the heterocyclic ring breathing
frequencies in the finger print region of 600–
1400 cm21 in these complexes [23]. The peaks at
about 1426 cm21 are attributed to the –CH3 vibration
of L anions. The bands at about 1038 and 1012 cm21
may be assigned to the internal vibrations of CH3C6H4
parts of L2 anion as described for CuL2 [24].
Table 2
The assignments of bands for 1–3 in the FT-IR spectra
Assignment
1
2
3
n (OH)coor.water
n (OH)lattice water
n (CvN)phen
n (CvC)phen
n (CH)phen
3562w
3443m
1584w
1517m
853s
3558w
3443m
1585w
1518m
853s
3555w
3441m
1585w
1518m
853s
815w
777w
721s
818m
779w
818m
781w
728s
728s
n (CH3)L
nas(SO3)
1424m
1187vs
1146m
1127m
1040s
1012s
688s
1426s
1184vs
1426s
1184vs
ns(SO3)
CH3C6H4 (internal vibrations)
1125m
1037s
1012s
688s
1126s
1038s
1012s
688s
n (C–S)
das(SO3)
ds(SO3)
570s
568s
568s
Compounds 1–3 show nas (SO3) and ns (SO3) in
the range 1184–1146 cm21 and 1125–1127 cm21
491w
490w
493w

336
J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
of the sulfonate group in the complex 1 may be
inferred as observed previously for Co(L)2(EtOH)2
[25]. The das (SO3) for 1–3 are observed at about
569 cm21, while the ds (SO3) appear at about
491 cm21 [26].
the difference of the electrochemical activity of the
metal cations [28]. As shown in Fig. 1a, the one-
electron reduction at 2202 mV can be assigned
tentatively to a metal-based CuII/CuI couple as
observed in other similar copper(II) o-phenanthroline
complexes [29]. On the basis of previously studied
data, the couple IV at E1=2 ¼ 82 mV can be described
as a reversible one-electron redox with the anodic to
cathodic peak separation ðDEÞ ¼ 87 mV and ia=ic ¼
0:9; where, ia and ic are the anodic and cathodic
currents, respectively [30]. Other peaks observed in
this CV plot may be assumed to be a result of
redox processes occurring at the ligands. In Fig. 1b
two reversible peaks with E1=2 ¼ 21424; 2 987 mV;
DE ¼ 90 and 170 mV were observed. One well solved
redox wave at 2100 mV was detected for the
cobalt(II) complex 2, which is assigned to the CoII/
CoI reduction, while an oxidation wave corresponding
to CoIII/CoII couple was not observed due to the
unstability of the Co(III) species [28, 31]. A typical
cyclic voltammetric response for the nickel(II)
complex 3 is displayed in Fig. 1c. Like the copper(II)
complex 1 and cobalt(II) complex 2, the ligand-based
oxidation and reduction waves also occurred in
complex 3. The peak I at 21888 mV, and the
irreversible couple II at E1=2 ¼ 21183 mV may be
assigned to the ligands. The couples of NiII/NiI (peak
III) at 2805 mV and NiIII/NiI (peak IV) at 343 mV
were also observed in Fig. 1c. The similar type of
electrochemical behavior was also known in the
previous nickel(II) complex [30, 32].
The solution spectral studies of the complexes in
the range 200–800 nm reveal that the intense
absorptions (at about lmax 275 nm) are due to the
p–pp transition of o-phenanthroline. This band is
blue-shifted upon coordination, showing clear evi-
dence of CvN coordination to metal (II) center [27].
In order to characterize more fully these com-
pounds in terms of thermal stability, we examined the
complexes 1 and 2 using TGA. The two complexes
were heated from 35 to 700 8C in N2. When the
crystals were removed from the mother liquor, they
immediately lost part of the water molecules. TGA
was performed after part of their water molecules had
evaporated. Weight losses corresponding to the
remaining water were observed over the wide
temperature range 35–105 8C for 1, and 35–120 8C
for 2. After dehydration, the anhydrous compounds
begin to decompose with loss of the organic portion at
temperature 310 and 340 8C, respectively. Other
exotherms centered at 350 and 470 8C for 1, 420
and 540 8C for 2, can be observed. However, it is
difficult to determine these weight losses accurately as
these processes are slightly overlapped with the
weight losses due to the dissociation of the organic
fractions. The final product of CuO and CoO was
obtained at 560 and 580 8C, respectively.
The redox properties of 1–3 were monitored by
CV in N; N-dimethylformamide (DMF) solution
containing 0.1 M TBAP, and these data are summar-
ized in Table 3. Compounds 1–3 show different
electrochemical activity, which may be attributed to
3.2. Crystal structures
Selected bond distances and angles are given in
Table 4. The structure of 1 is shown in Fig. 2. 1
consists of cationic species [Cu(phen)(L)(H2O)2]þ,
in which copper (II) ion is five-coordinated by two
nitrogen atoms of o-phenanthroline, two water
molecules and one sulfonate oxygen atom. Owing
to the weak coordination strength of sulfonate ion
toward transition metal ion, the other sulfonate ion
is non-coordinating. The Cu–N distances of 2.000
Table 3
Cyclic voltammetry data for complexes 1–3
Compound EI
EII
EIII
EIV
EV
EVI
1
2
3
21772a 21539a 2202a 82b
21424b 2987b 2100a
21888a 21183b 2805c 343c
248a 557a
˚
and 2.015 A are similar to those found in other
Cu(II) complex with o-phenanthroline [33], while
the copper water oxygen distances of 1.950 and
˚
1.984 A are near to the values found for
other Cu(II) complexes [34]. In the reported
a
b
c
Cathodic peak potential (EPC).
E1/2 ¼ (EPa 2 EPC)/2.
Anodic peak potential (EPa).

J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
337
Fig. 1. Cyclic voltammograms (a–c for 1–3, respectively) in DMF(c ¼ 1.0 £ 1023 mol l21, 0.1 mol l21 TBAP) at a glass carbon electrode
(scan rate ¼ 100 mV s21).
trans-di(4-methylbenzenesulfonato)bis(1,3-diamino-
propane)-copper (4) [6], the four equatorial N
atoms from two chelating 1,3-diaminopropane dis-
play stronger Jahn-Teller effect than two water
molecules and two N atoms from a chelating
o-phenanthroline of 1, hence axial Cu–O (sulfonate)
˚
distance of 2.581 A of 4 is much longer than that of 1
˚
(2.222 A). The phenyl ring of the coordinating
sulfonate group is parallel to o-phenanthroline plane
with the dihedral angle of 3.08.

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J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
Table 4
˚
Selected bond distances (in A) and angles (in 8) for compounds 1–3
[Cu(phen)(L1)(H2O)2]L1·H2O (1)
Cu–Ow1
Cu–N(1)
Cu–O(2)
S(1)–O(1)
1.984(3)
2.000(4)
2.222(3)
1.397(4)
Cu–Ow2
Cu–N(2)
S(1)–O(2)
S(1)–O(3)
1.950(4)
2.015(3)
1.435(3)
1.474(4)
Ow2–Cu–Ow1
Ow1–Cu–N(1)
Ow1–Cu–N(2)
Ow2–Cu–O(2)
N(1)–Cu–O(2)
90.07(17)
91.35(15)
165.81(14)
93.22(17)
92.02(14)
Ow2–Cu–N(1)
Ow2–Cu–N(2)
N(1)–Cu–N(2)
Ow1–Cu–O(2)
N(2)–Cu–O(2)
174.60(15)
95.27(15)
82.18(14)
88.68(13)
104.10(13)
[Co(phen)2(H2O)2]2L1·6H2O (2)
Co(1)–N(1)
2.1328(18)
2.0746(17)
Co(1)–N(2)
2.1395(19)
Co(1)–Ow1
Ow1–Co(1)–Ow1#1
Ow#1–Co(1)–N(1)#1
N(1)–Co(1)–N(2)#1
N(2)#1–Co(1)–N(2)
Ow1–Co(1)–N(1)#1
Ow1#1–Co(1)–N(2)#1
Ow1–Co(1)–N(2)
88.37(10)
95.55(7)
93.51(7)
88.98(10)
93.40(7)
92.05(8)
92.05(8)
93.51(7)
Ow#1–Co(1)–N(1)
Ow1–Co(1)–N(2)#1
N(1)–Co(1)–N(2)
93.40(7)
170.89(6)
77.50(7)
Ow1–Co(1)–N(1)
95.55(7)
N(1)–Co(1)–N(1)#1
N(1)#1–Co(1)–N(2)#1
Ow1#1–Co(1)–N(2)
167.50(10)
77.50(7)
170.89(6)
N(1)#1–Co(1)–N(2)
[Ni(phen)2(H2O)2]2L1·6H2O (3)
Ni(1)–N(1)
2.088(2)
Ni(1)–N(2)
2.092(2)
Ni(1)–Ow1
2.0748(19)
Ow1–Ni(1)–Ow1#1
Ow#1–Ni(1)–N(1)#1
N(1)–Ni(1)–N(2)#1
N(2)#1–Ni(1)–N(2)
Ow1–Ni(1)–N(1)#1
Ow1#1–Ni(1)–N(2)#1
Ow1–Ni(1)–N(2)
87.84(11)
95.68(8)
92.88(8)
91.06(12)
91.94(8)
91.17(8)
91.17(8)
92.88(8)
Ow#1–Ni(1)–N(1)
Ow1–Ni(1)–N(2)#1
N(1)–Ni(1)–N(2)
91.94(8)
171.40(7)
79.66(8)
95.68(8)
169.4(1)
79.66(8)
171.40(7)
Ow1–Ni(1)–N(1)
N(1)–Ni(1)–N(1)#1
N(1)#1–Ni(1)–N(2)#1
Ow1#1–Ni(1)–N(2)
N(1)#1–Ni(1)–N(2)
Symmetry code for 2 and 3: #1 2x þ 2; y; 2z þ 1:5
There are complicated hydrogen bonding inter-
actions in the structure of 1 (Fig. 3). Each oxygen
atom of the coordinating sulfonate ion is hydrogen-
bonded to one water molecule, while two oxygen
atoms of the non-coordinating sulfonate ion are
hydrogen-bonded to one water molecule respectively,
and the remaining oxygen atom has no hydrogen
bonding interaction. [Cu(phen)(L)(H2O)2]þ cations
and the non-coordinating sulfonate ions are linked by
hydrogen bonds to form infinite chains.
counter-anion and the other as a non-coordinating
counter-anion.
Complex 2 is isostructral with 3. Its structure is
shown in Fig. 4. Metal ion lies on a crystallographic
twofold axis. 2 consists of cationic species
[Co(phen)2(H2O)2]2þ, in which cobalt ion is six-
coordinated by four nitrogen atoms from two o-
phenanthroline molecules and two water oxygen
atoms. Due to the weak coordination strength of
sulfonate ion toward transition metal ion, the
sulfonate ions are non-coordinating. Indeed, there
are some examples where, the sulfonate group has
Complex 1 is a typical compound where,
one sulfonate ion is utilized as a coordinating

J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
339
Fig. 2. View of the structure of [Cu(phen)(L)(H2O)2]L·H2O with the numbering scheme.
been utilized as a non-coordinating counter-anion
water molecule is hydrogen-bonded to one lattice
water molecule and one sulfonate oxygen atom.
[Co(phen)2(H2O)2]2þ ions, sulfonate ions and lattice
water molecules are linked by hydrogen bonds to form
infinite zigzag chains (Fig. 5).
˚
[35]. The cobalt water oxygen distance of 2.075 A is
similar to the values in other cobalt compound [36].
˚
The Co–N distances of 2.133 and 2.140 A are near to
the values found in other cobalt complex with o-
phenanthroline [37].
Two oxygen atoms of the sulfonate ion are
hydrogen-bonded to one water molecule respectively,
and the remaining oxygen atom forms hydrogen
bonds with two water molecules. The coordinating
3.3. Conclusion
Three metal 4-methylbenzenesulfonate complexes
with o-phenanthroline were synthesized, and they
Fig. 3. The polymeric chain linked by hydrogen bonds in [Cu(phen)(L)(H2O)2]L·H2O.

340
J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
Fig. 4. View of the structure of [Co(phen)2(H2O)2]2L·6H2O with the numbering scheme.
Fig. 5. The polymeric zigzag chain linked by hydrogen bonds in [Co(phen)2(H2O)2]2L·6H2O.
displayed two different coordination modes. In
complex 1, one sulfonate ion coordinates to copper
ion, while the other plays a role of non-coordinating
counter-anion. The cations and the non-coordinating
sulfonate anions are linked by hydrogen bonds to form
infinite chains. In complexes 2 and 3, the weak
coordinating ability of the sulfonates relative to the
water molecules prevents the formation of direct M–
O–S bonds and two sulfonate ions only play a role
of counter-anions. The cations, non-coordinating
sulfonate ions and lattice water molecules are linked
by hydrogen bonds to form infinite zigzag chains. FT-
IR, CV, UV–Vis and TGA results are consistent with
the crystal structure.
Acknowledgements
This work was supported by the Fok Ying Tung
Education Foundation and the Ministry of Education
of China.

J. Yang et al. / Journal of Molecular Structure 657 (2003) 333–341
341
[15] L.J. Farrugia, WINGX, A Windows Program for Crystal
Structure Analysis, University of Glasgow, Glasgow, UK,
1988.
References
[1] A. Clearfield, in: M. Abe, T. Kataoka, T. Suzuki (Eds.), New
Developments in Ion Exchange Materials, Kodansha Ltd,
Tokyo, Japan, 1991. C.Y. Ortiz-Avila, C. Bhardwaj, A.
Clearfield, Inorg. Chem., 33, 1992, pp. 2499.
[16] International Tables for X-ray Crystallography, Kluwer, Vol.
C, Dordrecht, 1992.
[17] G.M. Sheldrick, SHELXTL PLUS, Structure Determination
Program, Siemens Analytical X-ray Instruments Inc, Madison,
WI, 1990.
[2] G. Cao, H. Hong, T.E. Mallouk, Acc. Chem. Res. 25 (1992)
420. G. Alberti, R. Polombari, Solid State Ion. 35 (1989) 153.
G. Alberti, M. Casciola, R. Palombari, Solid State Ion. 52
(1992) 291.
[18] A. Messimeri, C.P. Raptopoulou, V. Nastopoulos, A. Terzis,
S.P. Perlepes, C. Papadimitriou, Inorg. Chim. Acta 336
(2002) 8.
[3] M.E. Thompson, Chem. Mater. 6 (1994) 1168. S.B. Ungashe,
W.I. Wilson, H.E. Katz, G.R. Scheller, T.M. Putvinski, J. Am.
Chem. Soc. 114 (1992) 8717.
[19] S.Y. Niu, J. Jin, X.L. Jin, Z.Z. Yang, Solid State Sci. 4 (2002)
1103.
[20] B. Wang, H.-Z. Ma, Q.-Z. Shi, Inorg. Chem. Commun. 4
(2001) 409.
[4] B.Z. Wan, R.G. Anthony, G.Z. Peng, A. Clearfield, J. Catal.
101 (1994) 19. J.L. Colon, D.S. Thakur, C.Y. Yang, A.
Clearfield, J. Catal. 124 (1990) 148. D. Deniaud, B. Schollorn,
D. Mansuy, B.P. Rouxel, B. Bujoli, Chem. Mater. 7 (1995)
995.
[21] R.P. John, A. Sreekanth, M.R.P. Kurup, A. Isman, A.R.
Ibrahim, H.-K. Fun, Spectrochim. Acta Part A 59 (2003) 1359.
[22] L. Xu, E. Wang, J. Peng, R. Huang, Inorg. Chem. Commun. 6
(2003) 740.
[5] N.S. Husgen, G.A. Luinstra, F. Schaper, K. Schmidt, Inorg.
Chem. 37 (1998) 3471.
[23] M. Lalia-Kantouri, A. Hatzidimitriou, M. Uddin, Polyhedron
18 (1999) 3441.
[6] R.S. Markku, S. Reijo, Acta Chem. Scand. 47 (1993) 1173.
[7] M.B. Humphrey, W.M. Lamanna, M. Brookhart, G.R.
Husk, Inorg. Chem. 22 (1983) 3355. O.P. Anderson, A.B.
Packard, Inorg. Chem. 18 (1979) 1129. S. Komiya, J.C.
Huffman, J.K. Kochi, Inorg. Chem. 16 (1977) 2138. F.
Charbonnier, R. Faure, H. Loiseleur, Acta Crystallogr. Sect.
B 33 (1977) 1845.
[24] A.L. Arduini, M. Garnett, R.C. Thompson, T.C.T. Wong, Can.
J. Chem. 53 (1975) 3812.
[25] A. Guerrero-Laverat, A. Ranirez, A. Jeronimo, A. Santos, F.
Florencio, S. Martinez-Carrera, S. Garcia-Blanco, Inorg.
Chim. Chem. 128 (1987) 113.
[26] B. Sun, Y. Zhao, J.-G. Wu, Q.-C. Yang, G.-X. Xu, J. Mol.
Struct. 470 (1998) 63.
[8] P.L. Dedert, T. Sorrell, T.J. Marks, J.A. Ibers, Inorg. Chem.
21 (1982) 3506. F. Charbonnier, R. Faure, H. Loiseleur,
Acta Crystallogr. Sect. B 33 (1977) 1478. F. Charbonnier,
R. Faure, H. Loiseleur, Acta Crystallogr. Sect. B 34 (1978)
1504.
[27] J. Yang, J.-F. Ma, Y.-C. Liu, G.-L. Zheng, L. Li, J.-F. Liu,
J. Mol. Struct. 646 (2003) 55.
[28] E.I. Iwuoha, A.R. Williams-Dottin, L.A. Hall, Electeochim.
Acta 46 (2001) 3509.
[29] S.M. Morehouse, H. Suliman, J. Haff, D. Nguyen, Inorg.
Chim. Chem. 297 (2000) 411.
[9] J.S. Haynes, S.J. Retting, J.R. Sams, R.C. Thompson, J.
Trotter, Can. J. Chem. 65 (1987) 420.
[30] A.J. Blake, F. Demartin, F.A. Devillanova, A. Garau, F. Isaia,
V. Lippolis, V. Lippolis, M. Schroder, G. Verani, J. Chem.
Soc., Dalton Trans. (1996) 3705.
[10] E.J. Kosnic, E.L. McClymont, R.A. Hodder, P.J. Squattrito,
Inorg. Chim. Acta 201 (1992) 143. J.S. Haynes, S.J. Rettig,
J.R. Sams, R.C. Thompson, J. Trotter, Can. J. Chem. 64 (1986)
429. G. Smith, B.A. Cloutt, D.E. Lynch, K.A. Byriel, C.H.L.
Kennard, Inorg. Chem. 37 (1998) 3236. I. Murase, G.
Vuckovic, M. Kodera, H. Harada, N. Matsumoto, S. Kida,
Inorg. Chem. 30 (1991) 728.
[31] V.E. Marquez, J.R. Anacona, C.R. Barbarin, Polyhedron 20
(2001) 1885.
[32] E. Pereira, L. Gomes, B. Castro, Inorg. Chim. Acta 27 (1998)
83.
[33] O. Castillo, A. Luque, P. Roman, J. Mol. Struct. 570 (2001)
181.
[11] A.C.T. North, D.C. Phillipsand, F.S. Mathews, Acta Crystal-
logr. Sect. A 24 (1968) 351.
[34] D.M. Poojary, B.L. Zhang, P. Bellinghausen, A. Clearfield,
Inorg. Chem. 35 (1996) 4942.
[12] T. Higashi, Program for Absorption Correction, Rigaku
Corporation, Tokyo, Japan, 1995.
[35] R.E. Desimone, M.G. Glick, Inorg. Chem. 17 (1978) 3574. S.-
M. Peng, J.A. Ibers, M. Millar, R.H. Holm, J. Am. Chem. Soc.
98 (1976) 8037.
[13] G.M. Sheldrick, SHELXS-97 A Program for Automatic
Solution of Crystal Structure, University of Goettingen,
Germany, 1997.
[36] J.F. Ma, J.F. Liu, Y.C. Liu, Y. Xing, H.Q. Jia, Y.H. Lin, New
J. Chem. 24 (2000) 759.
[14] G.M. Sheldrick, SHELXL-97A Programs for Crystal Structure
Refinement, University of Goettingen, Germany, 1997.
[37] X.J. Yin, Y.M. Jiang, Chinese J. Struct. Chem. 20 (2001) 299.