Molecular and Electronic Structure of [PPh4][FeIIIL2]
Table 1. Crystallographic Data for 1 and 3
C64H60F10S2N2PFe: C, 64.16; H, 5.04; N, 2.34; Fe, 4.66. Found: C,
64.20; H, 5.07; N, 2.38; Fe, 4.71. ESI-MS (positive ion, CH2Cl2):
m/z ) 339.2 [PPh4]+; negative ion m/z ) 858.2 [FeL2]-.
1
3
chemical formula
C68H70F10FeN2OPS2
C40H40F10N2PtS2
997.95
[FeI(L•)2] (2). Complex 1 (0.19 g; 0.16 mmol) was dissolved in
dry dichloromethane (15 mL) under anaerobic conditions. To this
dark violet solution was added I2 (0.08 g; 0.32 mmol), dissolved
in n-hexane (15 mL), whereupon a color change from dark violet
to dark blue was observed. The reaction mixture was stirred under
Ar for 20 min, and the solvent was removed under vacuum. The
residue was redissolved in diethylether (20 mL) and filtered through
celite. Evaporation of the solvent under reduced pressure yielded
the product as a dark blue black microcrystalline solid. Yield:
0.08 g (51%). ESI-MS: m/z ) 985.1 {M}+. Anal. Calcd for
C40H40F10S2N2FeI: C, 48.74; H, 4.09; N, 2.84; Fe, 5.66; I, 12.87.
Found: C, 48.25; H, 3.86; N, 2.88; Fe, 5.24; I, 13.26.
fw
1272.20
P1, No. 2
j
space group
a, Å
b, Å
P21/c, No. 14
5.9917(2)
16.5057(5)
21.1653(7)
90
101.414(3)
90
2051.79(11)
2
13.3294(4)
14.5221(4)
17.4224(5)
101.401(3)
101.972(3)
98.963(3)
3165.2(2)
2
c, Å
R, deg
ꢀ, deg
γ, deg
V, Å
Z
T, K
100(2)
1.335
190(2)
1.615
F
calcd, g cm-3
reflns collected/2Θmax
unique reflns/I > 2σ(I)
params/restraints
λ, Å /µ(KR), cm-1
R1 a/GOFb
76 749/62.00
20 162/17 735
815/31
0.71073/4.03
0.0530/1.016
0.1130
29 937/65.00
7399/4906
256/0
0.71073/35.97
0.0352/1.005
0.0601
[Pt(L•)2] (3). To a solution of the ligand H2L (0.28 g; 0.69 mmol)
in dry CH3CN (15 mL) was added PtCl2 (0.09 g; 0.34 mmol) and
NEt3 (0.20 mL; 1.43 mmol). The solution was stirred for 10 min
under argon and was then exposed to air for ∼5 min, whereupon
the color of the solution changed from dark brown to dark green.
The solvent was removed under pressure and the solids reconstituted
in CH2Cl2 (15 mL). Slow evaporation from this solution afforded
3 as a green microcrystalline solid. Yield: 0.26 g (75%). Single
crystals of 3 were grown by slow evaporation from a 2:1 CH2Cl2/
CH3CN solution of the complex. Anal. Calcd for C40H40F10S2N2Pt:
C, 48.14; H, 4.04; N, 2.81; Pt, 19.54. Found: C, 48.22; H, 4.16; N,
2.91; Pt, 19.62. ESI-MS (neg. ion; CH2Cl2): m/z ) 997.2 [PtL2]-.
The cyclic voltammogram of 3 in CH2Cl2 (0.10 M [N(n-Bu)4]PF6;
c
wR2 (I > 2σ(I))
residual density, eÅ-3
+1.19/-1.15
+0.71/-0.93
a Observation criterion: I > 2σ(I). R1 ) Σ|Fo| - |Fc|/Σ|Fo|. b GOF )
c wR2 ) [Σ[w(Fo - Fc )2]/Σ[w(Fo )2]]1/2
,
2
2
2
2
2
[Σ[w(Fo - Fc )2]/(n - p)]1/2
.
2
2
2
where w ) 1/σ2(Fo ) + (aP)2 + bP, P ) (Fo + 2Fc )/3.
occupation ratio of about 53:47 were refined using a total of 31
restraints. Equal anisotropic displacement parameters were refined
for corresponding split atoms employing the EADP instruction of
ShelXL.7 SAME and SADI instructions were utilized to restrain
geometrical parameters of the split parts to be equal within errors.
Physical Measurements. The equipment used for IR, UV-vis,
EPR, and Mo¨ssbauer spectroscopies has been described in refs 8
and 9. The temperature-dependent magnetic susceptibilities of solid
samples of complexes were measured by using a SQUID magne-
tometer (Quantum Design) at 1.0 T magnetic field in the range of
2-300 K. Corrections for underlying diamagnetism were made by
using tabulated Pascal’s constants. Spin Hamiltonian simulations
of EPR spectra were performed with the XSOPHE program written
by Hanson et al., which is distributed by Bruker Biospin GmbH.
Ligand hyperfine interactions, including quadrupole interactions,
were considered with the full-matrix approach. Cyclic voltammetry
and coulometric experiments were performed using an EG&G
potentiostat/galvanostat. All potentials are referenced versus the
ferrocenium/ferrocene (Fc+/Fc) couple.
Calculations. All DFT calculations were performed with the
ORCA program package.10 The geometry optimizations of iron
complexes were carried out at the B3LYP level11,12 of DFT. Scalar
relativistic correction for iodine and Pt in 2 and 3, respectively,
were included using the zeroth-order regular approximation (ZORA)
method.13 All other details are described in ref 5 including the use
of corresponding,14 canonical, and quasi-restricted15 orbitals; density
plots were generated with Molekel.16 Nonrelativistic, single-point
calculations on the optimized geometries of iron complexes with
the B3LYP functional were carried out to predict Mo¨ssbauer
spectral parameters (isomer shift and quadrupole splittings). The
calculations employed the CP(PPP) basis set17 for iron and the
20 °C, glassy carbon working electrode, scan rate 100 mV s-1
)
shows three reversible one-electron transfer waves at E1/2 ) 0.74,
-0.53, and -1.34 V versus the ferrocenium/ferrocene (Fc+/Fc)
couple which correspond to the couples [3]+/[3]0, [3]0/[3]1-, and
[3]1-/[3]2-, respectively (see Supporting Information).
X-Ray Crystallographic Data Collection and Refinement of
the Structures. A black single crystal of 1 and a dark green crystal
of 3 were coated with perfluoropolyether, picked up with nylon
loops, and were mounted in the nitrogen cold stream of a Bruker-
Nonius KappaCCD diffractometer equipped with a Mo-target
rotating-anode X-ray source. Graphite monochromated Mo KR
radiation (λ ) 0.71073 Å) was used throughout. Final cell constants
were obtained from least-squares fits of all measured reflections.
Intensity data were corrected for absorption using intensities of
redundant reflections. The structures were readily solved by
Patterson methods and subsequent difference Fourier techniques.
The Siemens ShelXTL6 software package was used for solution
and artwork of the structures; ShelXL977 was used for the
refinement. All non-hydrogen atoms were anisotropically refined
and hydrogen atoms were placed at calculated positions and refined
as riding atoms with isotropic displacement parameters. Crystal-
lographic data of the compounds are listed in Table 1.
The diethylether solvate molecule (O100-C104) and a phenyl
ring (C81-C86) in the tetraphenylphosphonium cation in compound
1 were found to be disordered. Two split positions with an
(6) ShelXTL 6.14; Bruker AXS Inc.: Madison, WI, 2003.
(7) Sheldrick, G. M. ShelXL97; University of Go¨ttingen: Go¨ttingen,
Germany, 1997.
(8) (a) Ghosh, P.; Bill, E.; Weyhermu¨ller, T.; Wieghardt, K. J. Am. Chem.
Soc. 2003, 125, 3967. (b) Ghosh, P.; Begum, A.; Bill, E.; Weyher-
mu¨ller, T.; Wieghardt, K. Inorg. Chem. 2003, 42, 3208.
(9) Ray, K.; Bill, E.; Weyhermu¨ller, T.; Wieghardt, K. J. Am. Chem. Soc.
2005, 127, 5641.
(10) Neese, F. ORCAsAn Ab Initio, Density Functional Theoretical and
Semiempirical Electronic Structure Package, version 2.6, revision 4;
Institut fu¨r Physikalische und Theoretische Chemie, Universita¨t Bonn:
Bonn, Germany, 2007.
(11) Becke, A. D. J. Chem. Phys. 1986, 84, 4524.
(12) (a) Becke, A. D. J. Chem. Phys. 1993, 98, 5648. (b) Lee, C. T.; Yang,
W. T.; Parr, R. G. Phys. ReV. 1988, 37, 785.
(13) (a) van Wu¨llen, C. J. Chem. Phys. 1998, 109, 392. (b) van Lenthe,
E.; Baerendo, E. J.; Snijders, J. G. J. Chem. Phys. 1993, 99, 4597.
(14) Neese, F. J. Phys. Chem. Solids 2004, 65, 781.
(15) Scho¨neboom, J. C.; Neese, F.; Thiel, W. J. Am. Chem. Soc. 2005,
127, 5840.
(16) Molekel, advanced interactive 3D-graphics for molecular sciences,
(17) Neese, F. Inorg. Chim. Acta 2002, 337, 181.
Inorganic Chemistry, Vol. 47, No. 23, 2008 10913