2886
F. Cecconi et al. / Polyhedron 20 (2001) 2885–2888
Ag(CF3SO3) (0.26 g, 1 mmol) were stirred together in
acetone (20 ml) for 2 h. The reaction mixture was then
filtered to remove the AgBr precipitate. Ligand np3
(0.65 g, 1 mmol) was added to the filtrate and the
solution was stirred for 15 min, n-butanol (10 ml) was
then added. Concentration of the solution with a cur-
rent of nitrogen allowed the precipitation of a small
amount of colorless crystals of (np3)HgBr2 [4], which
were filtered off. Further concentration afforded color-
less microcystals of the title complex. These were
filtered, washed with n-butanol and then with pentane
and dried in a current of nitrogen. Recrystallization of
the product from dichloromethane/toluene afforded a
45% yield (0.54 g) of [Hg(C6F5)(np3)](CF3SO3)·CH2Cl2,
as well-shaped crystals. Anal. Calc. for C50H44Cl2F8-
HgO3NP3S: C, 47.84; H, 3.53; N, 1.12. Found: C, 50.0;
H, 3.65; N, 1.05%. 1H NMR (CD2Cl2, 295 K): l
7.9–7.0 (m, 30H, C6H5), 2.93 (m, 6H, CH2), 2.47 (s,
broad, 6H, CH2).
cell parameters were determined from a least-squares
refinement of the setting angles of 25 carefully centered
reflections. Crystal data and data collection details are
given in Table 1. On the basis of the systematic extinc-
tions, the space groups Pc and P2/c were both possible,
but the solution and the refinement of the structure
confirmed the acentric Pc was the correct one. On the
other hand, the presence in the asymmetric unit of two
independent molecules almost equal, pressed us to con-
trol very accurately also the possibility of the P2/c
space group. The intensities were rescaled and assigned
a standard deviation |(I) calculated using the value of
0.03 for the instability factor k [5]. The intensities were
corrected for Lorentz–polarization effects and an em-
pirical absorption correction was applied [6]. All the
calculations were performed in a Pentium processor,
using the programs SIR-92 [7], SHELX-93 [8] and ORTEP
[9]. Atomic scattering factors were taken from Ref. [10]
and an anomalous dispersion correction, real and imag-
inary parts, was applied [11]. The structure was solved
by direct methods and refined by full-matrix F2 refine-
ment, with anisotropic thermal parameters assigned to
mercury and phosphorus atoms. Hydrogen atoms were
introduced in their calculated positions riding on their
carbon atoms with thermal parameters 20% larger than
those of the respective carbon atoms. The absolute
structure was established, as described for polar space
groups by Flack [12]. The function minimized during
the refinement was Sw(F2o −Fc2 )2, with w=1/
[|2(F2o )+(0.098P)2+46.04P] where P=(max(F2o ,0)+
2F2c )/3. Some disorder was detected in the regions of
the triflate anions and of chloromethane solvent
molecules.
2.3. Crystallography
Diffraction data were collected at room temperature
on an Enraf–Nonius CAD4 automatic diffractometer
and graphite monochromatized Mo Ka radiation. Unit
Table 1
Crystal data and structure refinement parameters for [Hg(C6F5)-
(np3)](CF3SO3)·CH2Cl2
Empirical formula
Formula weight
Temperature (K)
C50H44Cl2F8HgNO3P3S
1255.32
293(2)
,
Wavelength (A)
0.71070
monoclinic
Pc
Crystal system
Space group
2.4. NMR spectra
Unit cell dimensions
,
a (A)
17.363(6)
10.280(6)
30.786(10)
90.000
104.01(3)
90.000
5332(3)
4
1.564
NMR spectra were recorded in 5 mm tubes, at 295
K, in a Bruker AC-200 spectrometer, operating at
200.13 MHz (1H), 81.015 MHz (31P) and 35.85 MHz
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
(
199Hg). Chemical shifts are relative to internal TMS,
external 85% H3PO4 and external 0.1 mol dm−3
Hg(ClO4)2 in 0.1 mol dm−3 HClO4, respectively, with
downfield values reported as positive.
3
,
Z
Dcalc (g cm−3
)
Absorption coefficient (mm−1
F(000)
)
3.185
2488
Crystal size (mm)
q Range for data collection (°) 2.50–20.06
0.40×0.20×0.10
3. Results and discussion
Index ranges
−165h516, 05k59, 05l529
1.49–8.24
0.8+0.35 tan q
5098
5098 [Rint=0.0000]
full-matrix least-squares on F2
5098/2/438
The crystal structure of the title compound consists
of [Hg(C6F5)(np3)]+ cations, (CF3SO3)− anions and
dichloromethane solvent molecules interspersed in the
lattice. Fig. 1 shows a perspective view of one of
the two crystallographically independent cationic
molecules. Table 2 reports selected bond distances and
angles.
Scan speed (° min−1
Scan width
)
Reflections collected
Independent reflections
Refinement method
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
R indices (all data)
1.034
R1=0.0660, wR2=0.1591
R1=0.1071, wR2=0.1814
In the asymmetric unit there are two independent
complex cations (A and B), which substantially differ in
Cecconi, Franco
