Synthesis and chemistry of tris(2-pyridyl)phosphine and bis(2-pyridyl)phenylphosphine complexes of mercury(II) X (X = Br, Cl) and X-ray crystal structural determination of [HgBr2(PPh(2-py) 22)22]

Article abstract of DOI:10.1080/00958972.2010.520083

Mercury(II) halide complexes [HgX₂(P(2-py)₃) ₂] (X = Br (1), Cl (2)) and [HgX₂(PPh(2-py) ₂)₂] (X = Br (3), Cl (4)) containing P(2-py)₃ and PPh(2-py)₂ ligands (P(2-py)<

Full text of DOI:10.1080/00958972.2010.520083

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Synthesis and chemistry of tris(2-
pyridyl)phosphine and bis(2-
pyridyl)phenylphosphine complexes
of mercury(II) X (Xꢀ=ꢀBr, Cl) and X-ray
crystal structural determination of
[HgBr2(PPh(2-py)2)2]
Ali Nemati Kharat a , Bahareh Tamaddoni Jahromi a , Abolghasem
Bakhoda a & Alireza Abbasi a
a School of Chemistry , University College of Science, University of
Tehran , Tehran, Iran
Published online: 13 Oct 2010.
To cite this article: Ali Nemati Kharat , Bahareh Tamaddoni Jahromi , Abolghasem Bakhoda
& Alireza Abbasi (2010) Synthesis and chemistry of tris(2-pyridyl)phosphine and bis(2-
pyridyl)phenylphosphine complexes of mercury(II) X (Xꢀ=ꢀBr, Cl) and X-ray crystal structural
determination of [HgBr2(PPh(2-py)2)2], Journal of Coordination Chemistry, 63:21, 3783-3791, DOI:
10.1080/00958972.2010.520083
To link to this article: http://dx.doi.org/10.1080/00958972.2010.520083
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Journal of Coordination Chemistry
Vol. 63, No. 21, 10 November 2010, 3783–3791
Synthesis and chemistry of tris(2-pyridyl)phosphine and
bis(2-pyridyl)phenylphosphine complexes of mercury(II)
X (X ^ Br, Cl) and X-ray crystal structural
determination of [HgBr2(PPh(2-py)2)2]
ALI NEMATI KHARAT*, BAHAREH TAMADDONI JAHROMI,
ABOLGHASEM BAKHODA and ALIREZA ABBASI
School of Chemistry, University College of Science, University of Tehran, Tehran, Iran
(Received 15 April 2010; in final form 16 July 2010)
Mercury(II) halide complexes [HgX2(P(2-py)3)2] (X ¼ Br (1), Cl (2)) and [HgX2(PPh(2-py)2)2]
(X ¼ Br (3), Cl (4)) containing P(2-py)3 and PPh(2-py)2 ligands (P(2-py)3 is tris(2-pyridyl)
phosphine and PPh(2-py)2 is bis(2-pyridyl)phenylphosphine) were synthesized in nearly
quantitative yield by reaction of corresponding mercury(II) halide and appropriate ligands.
The synthesized complexes are fully characterized by elemental analysis, melting point
determination, IR, 1H, and 31P-NMR spectroscopies. Furthermore, the crystal structure of
[HgBr2(PPh(2-py)2)2] determined by X-ray diffraction is also reported.
Keywords: Mercury(II) halide complex; P(2-py)3; PPh(2-py)2; 31P-NMR; X-ray diffraction
1. Introduction
Pyridylphosphines are convenient building blocks for the construction of transition
metal complexes [1–4]. Many transition metals preferentially bind through nitrogen of
pyridyl rings to form sandwich or half-sandwich complexes [5–8]. Especially, for the
ligands, such as P(2-py)3 and PPh(2-py)2, P-monodentate coordination modes are rare
[9–11]. Coordination and structural chemistry of mercury(II) halide complexes with
ligands containing a variety of donors has been a matter of interest over several decades
[12–15]. Following the seminal work of Mann and co-worker in 1940 [16], mercury(II)
halides are known to form a wide range of stoichiometrics with tertiary phosphine
ligands. By far, the most common are 1 : 1 and 2 : 1 complexes, (R3P)nHgX2 (n ¼ 1, 2;
X ¼ Cl, Br, I). The 2 : 1 complexes have a monomeric pseudo-tetrahedral structure with
degree of distortion depending on the ꢀ-donor ability and steric requirement of the
phosphines [17–20]. In this article, four complexes of Hg(II) with the previously
described [21, 22] pyridylphosphine, P(2-py)3 and PPh(2-py)2, are reported.
*Corresponding author. Email: alnema@khayam.ut.ac.ir
Journal of Coordination Chemistry
ISSN 0095-8972 print/ISSN 1029-0389 online ß 2010 Taylor & Francis
DOI: 10.1080/00958972.2010.520083

3784
A.N. Kharat et al.
2. Experimental
2.1. Materials and instruments
All manipulations for preparation of ligands were carried out under air and moisture-
free conditions under nitrogen, using standard Schlenk or glove box techniques. Diethyl
ether was dried over lithium aluminum hydride (LiAlH4) and freshly distilled prior to
use. Methanol, methylene chloride, n-butyllithium (15% solution in n-hexane),
2-bromopyridine, and phosphorus trichloride were purchased from Merck and except
for n-butyllithium, purified before use according to standard methods. DMF, HgCl2,
and HgBr2 were purchased from Fluka and were used as received. The ligands were
prepared as described previously [21, 22]. Melting points are uncorrected and were
obtained by an Electrothermal 9200 melting point apparatus. Infrared spectra from 250
to 4000 cmꢀ1 of solid samples were taken as 1% dispersion in CsI pellets using a
Shimadzu-470 spectrometer. 1H and 31P-NMR spectra were recorded at room
temperature in DMSO-d6 on a Bruker AVANCE 300 and 121.49 MHz, respectively.
The NMR spectra are referenced to Me4Si (1H) or H3PO4 85% (31P) as external
standards. Elemental analysis was performed using a Heraeus CHN–O Rapid analyzer.
2.2. Synthesis of [HgBr2(P(2-py)3)2] (1)
HgBr2 (0.077 mmol, 0.028 g) was dissolved in 10 mL MeOH and a solution of P(2-py)3
(0.039 mmol, 0.01 g) in 5 mL CH2Cl2 was added with vigorous stirring. A white
precipitate was immediately formed. The slurry was stirred for 30 min. The solvent was
completely removed, and the resulting white residue was washed with cold MeOH
(10 mL) and Et2O (10 mL) and finally dried in vacuo. White powder was recrystallized
from concentrated DMF solution. Yield 94.4%; m.p. ¼ 308ꢁC (dec). IR (cmꢀ1): 3047(w),
1651(b), 1570(m), 1508(w), 1447(m), 1422(s), 1283(w), 1151(w), 1082(w), 1042(w),
986(m), 764(s), 736(m), 617(w), 523(s), 510(s), 496(s), 420(w), 395(w), 279(w). 1H-NMR
(DMSO-d6, 300 MHz, 25ꢁC): ꢁ ¼ 7.57–7.59(d) (J ¼ 4.5), 7.82–7.86(m), 7.97(b),
31
8.69–8.70(d) (J ¼ 4.2). P-NMR (DMSO-d6, 121.4 MHz, 25ꢁC): ꢁ ¼ 16.73 ppm. Anal.
found: N 9.30%, C 40.58%, H 2.75%; Calcd for C30H24Br2HgN6P2 (890): N 9.43%,
C 40.44%, H 2.72%.
2.3. Synthesis of [HgCl2(P(2-py)3)2] (2)
This complex was prepared in a manner analogous to 1 where HgCl2 (0.077 mmol,
0.021 g) dissolved in 10 mL MeOH was used. Resulting white powder was recrystallized
from hot concentrated DMF solution. Yield 93.8%, m.p. ¼ 320ꢁC5(dec). IR (cmꢀ1):
3058(w), 2977(w), 1966(w), 1859(w), 1569(s), 1448(s), 1423(s), 1283(m), 1152(m),
1083(m), 1043(m), 987(s), 769(s), 738(s), 525(s), 508(s), 447(w), 422(w), 396(w), 292(w),
1
247(m). H-NMR (DMSO-d6, 300 MHz, 25ꢁC): ꢁ ¼ 7.59, 7.98, 8.68. 31P-NMR
(DMSO-d6, 121.4 MHz, 25ꢁC): ꢁ ¼ 16.05 ppm. Anal. found: N 10.36%, C 45.06%,
H 3.05%; Calcd for C30H24Cl2HgN6P2 (802): N 10.48%, C 44.93%, H 3.02%.

Pyridyl phosphine complexes with mercury
2.4. Synthesis of [HgBr2(PPh(2-py)2)2] (3)
3785
HgBr2 (0.077 mmol, 0.028 g) was dissolved in 10 mL MeOH and a solution of
PPh(2-py)2 (0.039 mmol, 0.01 g) in 5 mL CH2Cl2 was added with vigorous stirring.
A white precipitate was immediately formed. The slurry was stirred for 30 min.
The mixture of solvents was removed by rotary evaporator and the white residue was
washed with cold MeOH (10 mL) and Et2O (10 mL) and dried in vacuo. Resulting white
powder was recrystallized from concentrated DMF solution. Yield 94.7%;
m.p. ¼ 313ꢁC (dec). IR (cmꢀ1): 3043(m), 2981(w), 1568(s), 1481(m), 1450(s), 1422(s),
1320(w), 1283(m), 1155(w), 1099(m), 1045(w), 987(m), 768(s), 742(s), 691(s), 617(w),
1
511(s), 492(sh), 428(w), 395(w), 277(w). H-NMR (DMSO-d6, 300 MHz, 25ꢁC):
ꢁ ¼ 7.48–7.52(m), 7.56–7.61(m), 7.66–7.72(m), 8.58. 31P-NMR (DMSO-d6,
121.4 MHz, 25ꢁC): ꢁ ¼ 17.3 ppm (J ¼ 284). Anal. found: N 6.19%, C 45.21%,
H 2.99%; Calcd for C32H26Br2HgN4P2 (888): N 6.30%, C 43.24%, H 2.95%.
Crystals suitable for crystallographic structure determination were crystallized from hot
concentrated DMF solution.
2.5. Synthesis of [HgCl2(PPh(2-py)2)2] (4)
This complex was prepared in a manner analogous to 3 where HgCl2 (0.077 mmol,
0.021 g) dissolved in 10 mL MeOH was used. White powder was recrystallized from hot
concentrated DMF solution. Yield 96.1%; m.p. ¼ 318ꢁC (dec). IR (cmꢀ1): 3044(m),
2985(w), 1969(w), 1568(s), 1482(w), 1450(s), 1425(m), 1322(w), 1283(w), 1187(w),
1100(m), 1045(w), 988(s), 770(s), 744(s), 693(s), 618(w), 512(s), 429(w), 395(w), 248(w).
1H-NMR (DMSO-d6, 300 MHz, 25ꢁC): ꢁ ¼ 7.49–7.54(m), 7.58–7.61, 7.72–7.78(m),
7.89(b), 8.56(b). 31P-NMR (DMSO-d6, 121.4 MHz, 25ꢁC): ꢁ ¼ 17.31 ppm. Anal. found:
N 6.89%, C 48.19%, H 3.31%; Calcd for C32H26Cl2HgN4P2 (800): N 7.00%,
C 48.04%, H 3.28%.
2.6. Crystal structure determination and refinement
X-ray diffraction data were collected at room temperature on small crystals glued on
top of glass capillaries by means of a Stoe imaging plane. The X-Area program was
used for indexing and integrating the single crystal reflections. The structure of the title
compound was solved by direct methods using SHELXS-97 and refined by full matrix
least squares on F 2, SHELXL-97 [23]. Minimum and maximum final electron densities
were ꢀ0.969 to 0.614 eAꢀ3, respectively. Absorption corrections were performed with
˚
the programs X-RED [24] and X-SHAPE [25]. Symmetry equivalent reflections were
used to optimize crystal shape and size. All non-hydrogen atoms were refined
˚
anisotropically. Aromatic hydrogens were placed in calculated positions (C–H ¼ 0.93 A)
and treated as riding on the respective carrier atom, with Uiso(H) ¼ 1.2 (C). Plots were
produced with Diamond, and Mercury programs, and PLATON [26] software was used
to prepare materials for publication. A summary of the crystal data, experimental
details, and refinement results is given in table 1.

3786
A.N. Kharat et al.
Table 1. Crystallographic and structure refinements data for 3.
Formula
Formula weight
Temperature (K)
C32H26Br2HgN4P2
888.90
295(2)
0.71073
Monoclinic
P21/c
˚
Wavelength, ꢃ (A)
Crystal system
Space group
Unit cell dimensions (A,
ꢁ
˚
)
a
b
c
9.766(2)
19.316(4)
17.598(3)
100.72(3)
3261.8(11), 4
7.30
ꢄ
Volume (A ), Z
3
˚
Absorption coefficient (mmꢀ1
)
F(000)
1704
0.24 ꢂ 0.20 ꢂ 0.11
Crystal size (mm3)
ꢅ range for data collection (ꢁ)
Index ranges
2.1–26.0
ꢀ9 ꢃ h ꢃ 12;
ꢀ23 ꢃ k ꢃ 23;
ꢀ21 ꢃ l ꢃ 21
6402
0.058
0/370
1.01
R1 ¼ 0.0410,
wR2 ¼ 0.0586
R1 ¼ 0.0684,
wR2 ¼ 0.0634
0.61 and ꢀ0.97
Data collected
Rint
Restraints/parameters
Goodness of fit on F 2 (S)
Final R indices (obs. data)a
R indices (all data)a
ꢀ3
˚
Largest difference peak and hole (e A
)
2
aR1 ¼ ÆjjFoj ꢀ jFcjj/Æ|Fo|, wR2 ¼ [ÆðwðFo2 ꢀ Fc2Þ Þ/Æw(Fo2)2]1/2
.
3. Results and discussion
3.1. Synthesis of ligands and complexes
P(2-py)3 and PPh(2-py)2 were synthesized according to previously reported methods
from 2-lithiopyridine and appropriate chlorophosphine [21, 22], as shown in scheme 1.
Reaction of mercury(II) halides in methanol with P(2-py)3 and PPh(2-py)2, dissolved
in methylene chloride, in a 2 : 1 mole ratio resulted in white precipitates. Colorless
crystals of all complexes, suitable for X-ray analysis, were grown by slow evaporation
of concentrated DMF solution (scheme 2). The complexes were characterized by CHN
1
elemental analysis, melting point determination, IR, H and 31P-NMR spectroscopies.
The crystal structure of [HgBr2(PPh(2-py)2)2] was determined by X-ray single crystal
analysis. The ꢂ Hg–Cl vibrations were found at 270 and 271 cmꢀ1 [27]. The ꢂ Hg–Br
vibrations were not observed. The stretching vibrations of C¼C and C¼N bonds of
pyridine rings were found between 1422–1450 cmꢀ1 and 1568–1570 cmꢀ1 as strong
absorptions.
3.2. Investigation of 1–4 in the solution state
The 31P-NMR spectra of all complexes were recorded in DMSO-d6 and expected
1
satellites due to J(199Hg31P) coupling (199Hg 16.84% natural abundance, nuclear spin

Pyridyl phosphine complexes with mercury
3787
N
N
N
P
N
Br
2) PhPCl
2
P
N
N
Scheme 1. Synthesis of ligands.
py
py
py
py
P
X
X
P(2-Py) , MeOH
3
HgX
Hg
2
P
py
py
,
MeOH
2
X=Br, Complex (1) and X=Cl, Complex (2)
PhP(2-Py)
Ph
py
2-Py=
N
P
X
X
py
py
Hg
MeOH=Methanol
P
py
Ph
X=Br, Complex (3) and X=Cl, Complex (4)
Scheme 2. Synthesis of 1–4.
1
I ¼ 1/2) were observed. The ꢁ(31P) and J(199Hg31P) coupling constants are listed in
table 2. The 31P{1H}-NMR parameters of 1–4 are summarized in table 2. NMR data for
1–4 are consistent with structures in scheme 2, showing similar phosphorus.
The trend of the ꢁ(P) values in 1–4 (table 2) is the same. The same is true for the
1J(Hg–P) values for 1–4 in agreement with the same coordination mode for all complexes.

3788
A.N. Kharat et al.
Table 2. 31P{1H}-NMR data for 1–4.a
Compound
ꢁ(P)
1J(Hg–P)
1
2
3
4
16.73
16.05
17.30
17.31
349
2270
284
1048
aJ values in Hz. Spectra were run at 298 K. DMSO-d6 was used as
solvent.
1
According to table 2, the J(Hg–P) coupling constants for bromide complexes are
much smaller than chloride complexes. Generally, the J value is related to the
bond distance, the longer bond distance resulted in a low value of coupling
constant [28–30].
The 1H-NMR resonances (DMSO-d6) for the aromatic protons of pyridine rings for
1–4 occur between 7.48 and 8.70. For all of them, the integrated intensities are in
agreement with the proposed structures illustrated in scheme 2.
3.3. IR spectra
IR spectra of 1 and 2 show distinct vibrational bands at 1570, 1508, and 1569 cmꢀ1
assigned as C¼N bond vibrations (pyridine rings) and at 1447, 1423, 1448, and
1422 cmꢀ1 which were attributed to the C¼C bond vibrations. Bands at 617, 523, 510,
and 496 for 1, and 619, 525, and 508 cmꢀ1 for 2 are attributed to the vibrations of the
P–C bond. The IR spectra of 3 and 4 show distinct vibrational bands at 1568, 1481, and
1482 cmꢀ1 assigned as C¼N bond vibrations, and at 1450, 1422, and 1425 cmꢀ1 which
were attributed to the C¼C bond vibrations. Bands at 617, 510, and 492 for 3, and 618
and 512 cmꢀ1 for 4 have been attributed to P–C vibrations. Further information about
complex formation was obtained from Far-IR spectra. New bands at 247 and 248 cmꢀ1
have been assigned to Hg–Cl vibrations in 2 and 4, respectively [27].
3.4. Description of the molecular structure of [HgBr2(PPh(2-py)2)2] (3)
Colorless prismatic crystals of 3 were obtained by recrystallization of 3 in hot DMF.
Also, 3 crystallizes in the monoclinic space group P21/c (no. 14) with four molecules in
the unit cell. The structure consists of a mercury with two bromides and two
tris(2-pyridyl)phosphines that are monodentate P-donors, giving a distorted tetrahedral
˚
geometry, figure 1. The Hg–P (PhP(2-py)2) average bond distance is 2.5030(15) A and
˚
the Hg–Br average bond distance is 2.6309(8) A. These bond distances are comparable
to similar mercuric bromide–tertiary phosphine complexes [27–30].
All pyridine rings have nitrogens pointing in the same direction as the phosphorus
(figure 1). The phenyl rings A (C11–C16) and A0 (C27–C32) and pyridine rings B (N1/
C1/C5–C2), C (N2/C6/C10–C7), B0 (N3/C17/C21–C18), and C0 (N4/C23–C26/C22)
are, of course, planar. The dihedral angles between related rings in two different
(2-pyridyl)phenylphosphine moieties A to A0, B to B0, and C to C0 are 34.6ꢁ, 10.6ꢁ, and
27.0ꢁ, respectively.

Pyridyl phosphine complexes with mercury
3789
Figure 1. ORTEP diagram of [HgBr2(PPh(2-py)2)2] (3) with atom numbering scheme. Displacement
ellipsoids for non-H atoms are drawn at the 40% probability level.
Figure 2. Inter- and intramolecular ꢆ ꢄ ꢄ ꢄ ꢆ interactions in [HgBr2(PPh(2-py)2)2] (3).
Relatively strong intra ꢆ ꢄ ꢄ ꢄ ꢆ interactions exist between two pyridine rings (B and B0)
˚
from two different (2-pyridyl)phenylphosphine moieties (Cg1 ꢄ ꢄ ꢄ Cg3 ¼ 3.82 A, Cg1 and
Cg3 being the rings B and B0, respectively; figure 2). Crystal packing is dominated by
C–H ꢄ ꢄ ꢄ ꢆ and ꢆ ꢄ ꢄ ꢄ ꢆ interactions (figures 2 and 3) between neighboring molecules

3790
A.N. Kharat et al.
Figure 3. C–H ꢄ ꢄ ꢄ ꢆ interaction observed in packing of 3.
ꢁ
˚
Table 3. Selected bond distances (A) and angles ( ) for 3.
Hg(1)–P(1)
Hg(1)–P(2)
Hg(1)–Br(1)
Hg(1)–Br(2)
P(1)–C(1)
2.5124(15)
2.4937(15)
2.6194(8)
2.6424(11)
1.824(5)
1.811(6)
1.816(6)
1.827(5)
1.815(6)
1.826(6)
P(2)–Hg(1)–(P1)
P(2)–Hg(1)–Br(1)
P(1)–Hg(1)–Br(1)
P(2)–Hg(1)–Br(2)
P(1)–Hg(1)–Br(2)
Br(1)–Hg(1)–Br(2)
116.59(5)
111.43(4)
105.97(4)
111.31(4)
107.07(4)
103.52(3)
P(1)–C(6)
P(1)–C(11)
P(2)–C(17)
P(2)–C(22)
P(2)–C(27)
i
ii
˚
˚
(C14–H14 ꢄ ꢄ ꢄ Cg2 ¼ 2.90 A, Cg4 ꢄ ꢄ ꢄ Cg2 ¼ 3.97 A, Cg2 being the ring N2/C6/C10/C9/
i
ii
C8/C7, and Cg4, N4/C22/C26/C25/C24/C23, with ¼ x, 0.5 ꢀ y, ꢀ 0.5 þ z, and ¼ ꢀz,
ꢁ
˚
0.5 þ y, 0.5 ꢀ z). Crystallographic data, selected bond lengths (A) and angles ( ) are
listed in table 3.
4. Conclusion
Four 2 : 1 mercuric halide (bromide and chloride) complexes with two multidentate
pyridylphosphines, tris(2-pyridyl)phosphine, P(2-py)3, and bis(2-pyridyl)phenylpho-
sphine, PhP(2-py)2, were synthesized. These ligands are monodentate P-donors.
The synthesized complexes were characterized fully with IR and NMR. The 31P-NMR
spectra of these complexes are similar suggesting similar coordination modes.
The solid structure of [HgBr2(PPh(2-py)2)2] was determined by X-ray crystallography.

Pyridyl phosphine complexes with mercury
3791
The packing of [HgBr2(PPh(2-py)2)2] is stabilized by weak C–H ꢄ ꢄ ꢄ ꢆ and ꢆ ꢄ ꢄ ꢄ ꢆ
interactions.
Supplementary material
Full crystallographic details are deposited with the Cambridge Structural Database
Centre (CCDC No. 766530 for 3). Copies of the data can be obtained free of charge on
application to CCDC, 12 Union Road, Cambridge CB21EZ, UK (Fax:
(44)01223336033; Email: deposit@ccdc.ac.uk).
References
[1] F.R. Keene, M.R. Snow, P.J. Stephenson, E.R.T. Tiekink. Inorg. Chem., 27, 2040 (1988).
[2] R.P. Shutte, S.J. Rettig, A.M. Joshi, B.R. James. Inorg. Chem., 36, 5809 (1997).
[3] P.A. Anderson, T. Astley, M.A. Hitchman, F.R. Keene, B. Moubaraki, K.S. Murray, B.W. Skelton,
E.R.T. Tiekink, H. Toftlund, A.H. White. J. Chem. Soc., Dalton Trans., 3505 (2000).
[4] A. Steiner, D. Stalke. Organometallics, 14, 2422 (1995).
[5] Y. Ke-Wu, Y. Yuan-Qi, H. Zhong-Xian, W. Yun-Hua. Polyhedron, 15, 79 (1996).
[6] T. Astley, H. Headlam, M.A. Hitchman, F.R. Keene, J. Pilbrow, H. Stratemeier, E.R.T. Tiekink,
Y.C. Zhong. J. Chem. Soc., Dalton Trans., 3809 (1995).
[7] K.R. Adam, P.A. Anderson, T. Astley, I.M. Atkinson, J.M. Charnock, C.D. Garner, J.M. Gulbis,
T.W. Hambley, M.A. Hitchman, F.R. Keene, E.R.T. Tiekink. J. Chem. Soc., Dalton Trans., 519 (1997).
[8] J.A. Casares, P. Espinet, J.M. Martin-Alvarez, G. Espino, M. Perez-Manrique, F. Vattier. Eur. J. Inorg.
Chem., 289 (2001).
[9] C.J.L. Lock, M.A. Turner. Acta Crystallogr., Sect. C: Cryst. Struct. Commun., 43, 2096 (1987).
[10] K. Wajda, F. Pruchnik, T. Lis. Inorg. Chim. Acta, 40, 207 (1980).
[11] J.W. Faller, C. Blankenship, B. Whitmore, S. Sena. Inorg. Chem., 24, 4483 (1985).
[12] T.S. Lobana, A. Sanchez, J.S. Casas, A. Castineiras, J. Sordo, M.S. Garcia-Tasende,
E.M. Vazquez-Lopez. J. Chem. Soc., Dalton Trans., 4289 (1997).
[13] T.S. Lobana, M.K. Sandhu, M.J. Liddell, E.R.T. Tiekink. J. Chem. Soc., Dalton Trans., 691 (1990).
[14] C.M.V. Stalhandske, I. Persson, M. Sandstrom, M. Aberg. Inorg. Chem., 36, 4945 (1997).
[15] K.K. Cheung, R.S. McEwen, G.A. Sim. Nature, 23, 383 (1965).
[16] R.C. Evans, F.G. Mann, H.S. Peiser, D. Purdie. J. Chem. Soc., 1209 (1940).
[17] N.A. Bell, T.D. Dee, M. Goldstein, P.J. McKenna, I.W. Nowell. Inorg. Chim. Acta, 71, 135 (1983).
[18] N.A. Bell, T.D. Dee, M. Goldstein, T. Jones, I.W. Nowell, P.L. Goggin, R.J. Goodfellow, K. Kessler,
D.M. McEwan. J. Chem. Res., (S) 2, (M) 0201 (1981).
[19] D.W. Allen, N.A. Bell, S.T. Fong, L.A. March, I.W. Nowell. Inorg. Chim. Acta, 99, 157 (1985).
[20] N.A. Bell, L.A. March, I.W. Nowell. Inorg. Chim. Acta, 156, 195 (1989).
[21] K. Kurtev, D. Ribola, R.A. Jones, D.J. Cole-Hamilton, G. Wilkinson. J. Chem. Soc., Dalton Trans.,
55 (1980).
[22] Y. Xie, C.L. Lee, Y. Yang, S.J. Rettig, B.R. James. Can. J. Chem., 70, 751 (1992).
[23] G.M. Sheldrick. SHELXS-97 and SHELXL-97, University of Gottingen, Germany (1997).
[24] Stoe & Cie. X-RED, Program for Data Reduction and Absorption Correction (Version 1.28b), Stoe & Cie
GmbH, Darmstadt, Germany (2005).
[25] Stoe & Cie. X-SHAPE, Program for Crystal Optimization for Numerical Absorption Correction
(Version 2.05), Stoe & Cie GmbH, Darmstadt, Germany (2004).
[26] A.L. Spek. J. Appl. Cryst., 36, 7 (2003).
[27] W. Oberhauser, T. Stempfl, R. Haid, C. Langes, C. Bachmann, H. Kopacka, K.H. Ongania,
P. Bruggeller. Polyhedron, 20, 727 (2001).
¨
[28] S.K. Hadjikakou, M. Kubicki. Polyhedron, 19, 2231 (2000).
[29] N.A. Bell, S.J. Coles, M.B. Hursthouse, M.E. Light, K.A. Malik, R. Mansor. Polyhedron, 19, 1719
(2000).
[30] N.A. Bell, S.J. Coles, C.P. Constable, M.B. Hursthouse, M.E. Light, R. Mansor, N.J. Salvin.
Polyhedron, 21, 1845 (2002).