Synthesis, molecular structure and electrochemistry of gold(I) complexes with 1-(diphenylphosphino)-1′-[(diphenylphosphino)methyl]ferrocene

Article abstract of DOI:10.1016/j.jorganchem.2012.06.007

Depending on the reaction stoichiometry, 1-(diphenylphosphino)-1′- [(diphenylphosphino)methyl]-ferrocene (1) reacts with [AuCl(tht)] (tht = tetrahydrothiophene) to afford an insoluble polymer formulated as [AuCl(1)] _n (2) or ligand-bridged digold(I) complex, [(μ-1)(AuCl) ₂] (3). The latter compound readily undergoes metathesis reactions with anionic reagents such as in situ generated acetylides, thiocyanate or N,N-diethyldithiocarbamate to give the corresponding digold(I) complexes [(μ-1)(AuY)₂], where Y is CCPh (4), CCFc (5; Fc = ferrocenyl), SCN (6), and Et₂NCS₂ (7). Similar reaction of 3 with a dithiolate formed from propane-1,3-dithiol and sodium methoxide affords a macrocyclic bis-chelate [(μ-1)(AuSCH₂CH₂CH ₂SAu)] (8). Compounds 2-8 have been characterized by spectroscopic methods (multinuclear NMR, ESI, MS, UV-vis and IR) and by elemental analysis, and the molecular structures of 3·C₂H₄Cl ₂, 4·2CHCl₃, 7·2CHCl₃, and 8 have been determined by single-crystal X-ray diffraction analysis. Cyclic voltammetric study revealed that ligand 1 undergoes a one-electron oxidation at the ferrocene unit, which is associated with some chemical complications resulting presumably from the presence of the lone electron pair at phosphorus. After coordination to Au(I)L fragments bearing simple auxiliary ligands (e.g., in 3, 4, and 6), the Fe^II/Fe^III redox process becomes reversible and appears shifted to more positive potentials owing to an electron density transfer from the diphosphine ligand to the coordinated metal centers. For compounds 5 and 7, this redox change is accompanied by additional waves attributable to oxidation of ferrocenyl groups in the terminal ferrocenylethynyl groups and to redox changes occurring at the Au-bound carbamate ligands, respectively.

Full text of DOI:10.1016/j.jorganchem.2012.06.007

Journal of Organometallic Chemistry 716 (2012) 110e119
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Journal of Organometallic Chemistry
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Synthesis, molecular structure and electrochemistry of gold(I) complexes with
1-(diphenylphosphino)-10-[(diphenylphosphino)methyl]ferrocene
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Petr Stepnicka , Ivana Císarová
Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague, Hlavova 2030, 12840 Prague, Czech Republic
a r t i c l e i n f o
a b s t r a c t
Depending on the reaction stoichiometry, 1-(diphenylphosphino)-10-[(diphenylphosphino)methyl]-
Article history:
Received 5 June 2012
Received in revised form
12 June 2012
ferrocene (1) reacts with [AuCl(tht)] (tht ¼ tetrahydrothiophene) to afford an insoluble polymer
formulated as [AuCl(1)]n (2) or ligand-bridged digold(I) complex, [(m-1)(AuCl)2] (3). The latter compound
readily undergoes metathesis reactions with anionic reagents such as in situ generated acetylides,
thiocyanate or N,N-diethyldithiocarbamate to give the corresponding digold(I) complexes [( -1)(AuY)2],
Accepted 12 June 2012
m
where Y is C^CPh (4), C^CFc (5; Fc ¼ ferrocenyl), SCN (6), and Et2NCS2 (7). Similar reaction of 3 with
Keywords:
Ferrocene ligands
Phosphines
a dithiolate formed from propane-1,3-dithiol and sodium methoxide affords a macrocyclic bis-chelate
[(m-1)(AuSCH2CH2CH2SAu)] (8). Compounds 2e8 have been characterized by spectroscopic methods
(multinuclear NMR, ESI, MS, UVevis and IR) and by elemental analysis, and the molecular structures of
3$½C2H4Cl2, 4$2CHCl3, 7$2CHCl3, and 8 have been determined by single-crystal X-ray diffraction analysis.
Cyclic voltammetric study revealed that ligand 1 undergoes a one-electron oxidation at the ferrocene
unit, which is associated with some chemical complications resulting presumably from the presence of
the lone electron pair at phosphorus. After coordination to Au(I)L fragments bearing simple auxiliary
ligands (e.g., in 3, 4, and 6), the FeII/FeIII redox process becomes reversible and appears shifted to more
positive potentials owing to an electron density transfer from the diphosphine ligand to the coordinated
metal centers. For compounds 5 and 7, this redox change is accompanied by additional waves attrib-
utable to oxidation of ferrocenyl groups in the terminal ferrocenylethynyl groups and to redox changes
occurring at the Au-bound carbamate ligands, respectively.
Gold(I) complexes
Structure elucidation
Electrochemistry
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
In view of our previous studies aimed at understanding the
coordination behavior of ferrocene-based P,N-donors possessing an
The somewhat stagnant coordination chemistry of gold(I) [1]
has recently revived due to the discovery of new interesting
structures, fundamentally attractive goldegold closed-shell inter-
actions [2] and, mainly, because of numerous applications of gold(I)
complexes in materials research [3], homogeneous catalysis [4] and
biomedicine [5]. As a soft metal ion forming usually stable linear
coordination assemblies, gold(I) has been also utilized as a defined
building block for the preparation various coordination arrays [6]
via substitution and complexation reactions, being often
combined with ferrocene-based metalloligands. The majority of
Au(I)eFe(II) complexes [7] has been obtained from the ubiquitous
1,10-bis(diphenylphosphino)ferrocene (dppf) [8]. Compounds
resulting from ferrocene monophosphines such as FcPPh2
(Fc ¼ ferrocenyl) [9], FcCH2PPh2 [10], FcCH2P(CH2OH)2 [11] and
(FcC^C)nPPh2ꢀn (n ¼ 1,2) [12] remain still less common.
inserted methylene group (A and B in Scheme 1) toward Au(I) [13],
we decided to also include in testing the recently reported semi-
homologous dppf congener
1 [14] (Scheme 1). This study
describes the preparation of a bis(chlorogold(I)) complex from this
unsymmetric diphosphine ligand and its further reactions with
anionic reagents to give a series of trimetallic Au2Fe complexes.
Also reported are a detailed structural characterization of these
newly prepared compounds by means of spectroscopic methods
and single-crystal X-ray crystallography, and investigations into
their electrochemical properties.
2. Results and discussion
2.1. Synthesis and spectroscopic characterization
Initial reaction tests were aimed at understanding the course of
the reactions occurring in the 1e[AuCl(tht)] system
(tht ¼ tetrahydrothiophene). To this end, appropriate amounts of
* Corresponding author. Fax: þ420 221 951 253.
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E-mail address: stepnic@natur.cuni.cz (P. Stepnicka).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.06.007

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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
111
PPh
PPh
PPh
2
2
2
Fe
Fe
Fe
NMe
PPh
2
2
N
A
B
1
Scheme 1.
these starting materials were dissolved in CDCl3 and the reaction
mixtures were monitored by 1H and 31P{1H} NMR spectroscopy.
When mixed at a 1:1 M ratio, the starting materials quickly dis-
solved to produce a clear yellow solution, which then slowly
deposited a fine yellow precipitate. NMR spectra recorded shortly
after mixing revealed a single AueFe compound to be formed along
with liberated tht (Fig. 1). The 31P NMR signals of the product were
markedly broadened, probably due to dynamic processes. The
yellow solid product, which separated almost completely after
Fig. 1. 31P{1H} NMR (left) and 1H NMR (right) spectra of reaction mixtures prepared by
mixing [AuCl(tht)] with diphosphine 1 at 1:1 (bottom) and 2:1 (top) molar ratios in
CDCl3. For 1H NMR spectra, only the region of ferrocene and CH2 protons is shown for
clarity. The signals in the 31P{1H} NMR spectrum of in situ generated 3 (shown on top)
have different widths but integrate to the same intensity.
standing at 4 ꢁC overnight (86% isolated yield at 20
mmol scale), was
isolated and analyzed as a 1:1, probably polymeric complex
[AuCl(1)] (2). It should be noted that formation of an intermediate
[AuCl(PP)] complex and its easy polymerization to give [AuCl(PP)]n
was noted earlier for dppf (¼PP) [7f,7g], and that a defined
molecular [AuCl(PP)] “intermediate” was later isolated upon
bis(h
1-alkynyl) complexes 4 and 5, Au(I)-thiocyanate 6 and carba-
mate 7, respectively. Similar reaction of 3 with propane-1,3-
ditiolate gave a 13-membered trimetallamacrocycle 8, for which
a counterpart can be found in the chemistry of dppf [16].
Compounds 3e8 were isolated as yellow, air-stable solids and
were characterized by elemental analysis, 1H and 31P{1H} NMR
spectroscopy, UVevis spectroscopy and by electrospray ionization
(ESI) mass spectrometry. In addition, the crystal structures of four
representatives were determined by X-ray crystallography and the
whole series of Au(I) complexes except for insoluble 8 was studied
by cyclic voltammetry.
replacing dppf with its bulky permethylated analogue, [Fe(h5
-
C5Me4PPh2)2] [15].
A similar reaction of 1 with two equivalents of [AuCl(tht)]
(Au:P ¼ 1:1) afforded a clear deep yellow solution, which also
contained a single product according to the NMR spectra (Fig. 1).
This product was identified as the expected bis(chlorogold)
complex 3 (Scheme 2).
In the 1H NMR spectra, compounds 3e8 displayed four reso-
nances due to the chemically non-equivalent protons at the ferro-
cene-1,10-diyl unit, a multiplet of the phosphine phenyls and
a characteristic doublet of the PCH2 group (2JPH ¼ 10e11 Hz). For
3e7, the methylene signal was seen in a rather narrow range dH
3.57e3.72, while in the case of 8, it appeared shifted to considerably
Repeating the later reaction at a larger scale produced a good
yield of the air-stable yellow complex 3, which was used as
a convenient entry to other Au(I)eFe(II) complexes via metathesis-
like reactions with various anionic reagents (Scheme 2). Thus,
treatment of 3 with in situ formed sodium acetylides, sodium
thiocyanate and sodium N,N-diethyldithiocarbamate afforded
Ph
Ph
Ph
Ph
Au
Cl
P
P
HS(CH ) SH/MeONa
2 3
Au
Au
2[AuCl(tht)] + 1
Fe
Fe
- tht
- NaCl, - MeOH
S
P
Cl
Ph
Ph
3
P
Au
Ph
S
RC CH/MeONa
- NaCl, - MeOH
Et NCS Na
2
2
Ph
8
KSCN
- KCl
- NaCl
R
Et N
2
N
C
C
S
Ph
Ph
C
Ph
Ph
Ph
Au
Ph
C
S
S
P
P
P
Au
Au
Au
Au
Au
Fe
Fe
Fe
P
P
C
S
P
S
Ph
Ph
Ph
S
C
C
C
Ph
Ph
Ph
NEt
R
N
2
4 (R = Ph)
5 (R = Fc)
7
6
Scheme 2. Synthesis of compounds 3e8 (Fc ¼ ferrocenyl).

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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
112
higher fields (dH 2.79). The 1H NMR spectra further exhibited
signals due to the anionic ligands, namely characteristic multiplets
of the phenyl and ferrocenyl groups for 4 and 5, respectively, signals
of to the virtually equivalent ethyl groups in 7, and signals of the
trimethylene bridge in the macrocyclic complex 8. The 31P NMR
spectra of 3e8 showed two resonances (singlets) for the non-
equivalent phosphorus atoms. The positions of these signals
varied upon changing the ‘terminal’ donors attached to Au(I) with
dP increasing with increasing trans-influence [17] of the terminal
ligand (dP: 3 < 7 < 6 < 8 < 4 z 5). Finally, the presence of the
thiocyanato ligands in 6 was clearly manifested in the IR spectrum
through a pair of diagnostic bands at 2120 and 2076 cmꢀ1 [18].
With the exception of compound 7, the positive-ion ESI mass
spectra of all molecular Au(I) complexes displayed intense signals
at m/z 765 corresponding to [Au(1)]þ (N.B. Only this signal was
observed for compound 6 under standard conditions). In contrast,
the spectrum of compound 7 showed only ions resulting via
elimination of one anionic ligand (m/z 1110). In addition to the
mentioned ion at m/z 765, the spectra of 3e5 and 8 exhibited
signals attributable to the molecular and/or pseudomolecular (e.g.,
[M þ Na]þ) ions and ions resulting by elimination of one terminal
ligand (chloride or acetylide; not possible for 8).
recrystallization as specified in the Experimental section. Views of
the molecular structures are presented in Figs. 3e5 and 7. Pertinent
geometric data are given in Table 1.
The Au-donor bond lengths in 3 compare well with those
reported earlier for [(dppf)(AuCl)2] [7a,7m,19], [(FcCH2PPh2)AuCl]
[10] and for phosphineeAuCl complexes obtained from phosphi-
noferrocene pyridines [13a] and phosphinoamine B (Scheme 1)
[13b]. The two AueP distances in 2 are practically identical. The
AueCl bond lengths differ by only ca. 0.01 Å, the shorter AueCl
bond and the wider PeAueCl angle being associated with Au2
connected to the less encumbered CH2PPh2 group.
The structure of 4 reveals nearly linear coordination for both
Au(I) ions. The geometry of PeAueacetylide fragments is similar to
that reported for [(m-dppf)(AuC^CFc)2] [20] and complexes of the
type [(FcPPh2)AuC^CR], where R ¼ Fc, 4-C6H4CN, 2,5-bis(N,N-
dimethylaminomethyl)-4-iodophenyl and 2,20-bipyridine-3-yl [9b].
Likewise, parameters describing the coordination geometry of 7 do
not depart much from those reported for [(R3P)Au(dtc)], where
R ¼ phenyl [21] and 2-tolyl [22], and for the dppe-bridged complex
[(
m
-dppe){Au(dtc)}2] (dppe ¼ 1,2-bis(diphenylphosphino)ethane,
dtc ¼ N,N-diethylcarbamodithioato) [23].
In 7, the versatile dtc ligands [24] coordinate in essentially
monodentate fashion. This is particularly evident in the case of Au1
showing unlike Au1eS1/2 distances (Au1eS1 2.337(1) Å, Au2eS2
3.047(1); cf. the sum of the covalent radii being 2.38 Å [25]). For
Au2, this bond asymmetry is significantly lower (Au2eS3
2.3559(9) Å, Au2eS4 2.918(1) Å), which in turn corresponds with
The UVevis spectrum (Fig. 2) of complex 3 recorded in 1,2-
dichloroethane consisted a composite band tailing off from the
UV region. Compounds possessing terminal ligands capable of
p-conjugation displayed more intense bands shifted toward lower
energies. For instance, the dithiocarbamate complex 7 showed at
strong band at 265 nm and a composite band extending to longer
wavelengths (with a maximum at ca. 292 nm). In the case of ace-
tylide 5, the “main” band was shifted to 292 nm while the phe-
nylethinyl analogue 4 showed a composite band consisting of a pair
of sharp, intense bands at 270 and 284 nm, a relatively weaker band
at 258 nm and a shoulder around 293 nm. Even these bands were
accompanied by relatively weaker bands extending toward lower
energies.
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a more pronounced delocalized character of the CS2 moiety
bonding to Au2 (cf. the difference in the CeS bond lengths being ca.
0.06 and 0.03 Å for dtc ligands attached to Au1 and Au2, respec-
tively). The close approach of the second sulfur atom to the Au(I)
centers is further reflected by a closure of the PeAueS angles (ca.
172ꢁ for both Au1 and Au2) [26].
An inspection of the data presented in Table 1 reveals that the
AueP bond distances increase with increasing trans-influence [17]
of the other ligand coordinated to the gold(I) center (i.e.,
4 > 8 > 7 > 3). It is also noteworthy that the molecules of 3, 4 and 7
bearing simple terminal ligands share the overall molecular
conformation (see Fig. 8 and torsion angles in Table 1 [27]). In all
three cases, the PPh2 group attached directly to the ferrocene unit is
oriented so that the P1eAu1edonor arm points toward the ferro-
cene unit with Au1 located on the side accommodating the meth-
ylene spacer. The methylene group linking the second
phosphinogold moiety is approximately perpendicular to the plane
of its parent ring Cp2 and the P2eAu2edonor arm extends away
from the ferrocene core and from Au1.
2.2. Molecular structures
The formulation of compounds 3, 4, 7 and 8 was unequivocally
corroborated by single-crystal X-ray diffraction analysis for solvates
for 3$½C2H4Cl2, 4$2CHCl3, 7$2CHCl3 and
8 isolated after
Fig. 2. UVevis spectra of ligand 1 and complexes 3, 4, 5 and 7 as recorded for ca.
2 ꢂ 10ꢀ5 M solutions in 1,2-dichloroethane (optical path 1.0 cm).
Fig. 3. View of the complex molecule in the crystal structure of 3$½C2H4Cl2.
Displacement ellipsoids correspond to the 30% probability level.

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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
113
Fig. 4. View of the complex molecule in the structure of 4$2CHCl3. Displacement
ellipsoids correspond to the 30% probability level. Only one position of the disordered
phenyl ring C(46e51) is shown for clarity.
Fig. 6. Views of the molecules of 3 and 8 in the Cg1/Cg2 direction (i.e., along the axis
of the ferrocene moiety). Hydrogen atoms are omitted for clarity.
Ferrocene units in the molecules of 3, 4 and 7 are regular and
assume conformations close to synclinal eclipsed (cf. the ideal value
s
the ferrocene unit. However, the C11eP2 bond is inclined toward P1
(cf. C7eC6eC11eP2 angles in Table 1) and the P2eAu2eS2 arm and
one of the phenyl groups at P2 are found in mutually interchanged
positions. As a result, both gold atoms are located on one side of the
ferrocene unit with the vectors of the AueP bonds being close to
parallel, thus facilitating the closure of the macrocycle. Notably, the
conformation of 8 differs from that observed for the dppf analogue
in which the cyclopentadienyl rings adopt a synclinal eclipsed
conformation while the PeAueS arms are arranged in a staggered
manner, thereby allowing for an intramolecular aurophilic contact
(Au/Au z 3.06 Å) [29].
It is also noteworthy that with the exception of complex 3, the
compounds studied do not form any significant intra- or intermo-
lecular aurophilic contacts [2] in the solid state (Au/Au ꢃ ca. 5 Å).
In the case of complex 3 (Fig. 8), the Au1 atoms from proximal
molecules related by the crystallographic two-fold axis are
involved in a weak aurophilic interactions with Au1/Au10 distance
of 3.2502(2) Å, which is shorter than double the van der Waals
radius (ca. 3.32 Å [25]). The torsion angles XeAu1eAu10eX0 are
108ꢁ for both X ¼ Cl and P. The second shortest intermolecular
contact in the structure of 3 is detected between Au2 atoms in a
¼ 72ꢁ). Surprisingly, the most pronounced departure from the
regular geometry is seen for complex 3 featuring monoatomic
terminal ligands. This compound shows the largest tilt angle
(ca. 4ꢁ) and its substituents are the most distant in the series due to
the largest mutual rotation of the cyclopentadienyl rings.
Despite the presence of a relatively short bridge, the structure
of ferrocenophane-like compound 8 (Fig. 7) remains undistorted
with the interatomic distances and angles falling within the usual
ranges. For instance, the individual AueP and AueS distances in 8
are similar to each other and compare well with the data
reported for the dppf analogue [(dppf)(AuSCH2CH2CH2SAu)]
[16,28], which can be expected to be more strained owing to
an absence of the flexible methylene spacer. The PeAueS angles
in 7 depart from linearity by ca. 10ꢁ (Au1) and 6ꢁ (Au2), which
is less than in the dppf analogue showing the PeAueS angles of
ca. 165ꢁ.
The overall molecular conformation of 8 differs from that found
for the compounds with non-bridging terminal ligands discussed
above. As shown in Fig. 6 the ferrocene cyclopentadienyls remain
close to synclinal eclipsed and the CH2PPh2 group is oriented above
Fig. 5. View of the complex molecule in the structure of 7$2CHCl3 showing
Fig. 7. View of the molecular structure of 8. Displacement ellipsoids are scaled to 30%
displacement ellipsoids at the 30% probability level.
probability level.

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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
Table 1
Table 2
Selected distance and angles (in Å and deg) for 3$½C2H4Cl2, 4$2CHCl3, 7$2CHCl3, and
8.
Summary of electrochemical data for 1e6.a
E0 [V]
0
Compound
E0 [V]
0
Compound
Parametera
3$½C2H4Cl2
4$2CHCl3
7$2CHCl3
8g
e
f
1
3
4
0.070
0.400
0.365b
5
6
7
ꢀ0.005,c 0.370
X/Y
Au1eP1
Au1eX
P1eAu1eX
Au2eP2
Cl1/Cl2
C36/C44
2.272(1)
1.999(6)
177.7(2)
2.272(1)
2.012(4)
178.8(1)
S1/S3
S1/S2
0.425
2.233(1)
2.296(2)
175.29(5)
2.231(1)
2.286(2)
177.02(5)
7.6959(3)
91.2(5)
2.2495(9)
2.337(1)
171.98(3)
2.2459(9)
2.3559(9)
172.12(3)
7.4143(2)
ꢀ91.7(4)
ꢀ62.4(3)
26.5(4)
2.2612(8)
2.2896(9)
170.24(4)
2.2702(9)
2.287(1)
174.08(4)
5.4181(2)
66.4(4)
ꢀ55.1(3)
ꢀ144.6(3)
161.70(4)
1.648(2)
1.651(2)
0.6(2)
ca. 0.445d
a
The redox potentials were determined as an average of the anodic (Epa) and
cathodic (Epc) peak currents in cyclic voltammograms and are given relative to
ferrocene/ferrocenium. For details, see Experimental.
Au2eY
b
The redox process is complicated by adsorption phenomena.
Oxidation of the terminal ferrocenyl groups.
The ferrocene-based oxidation is accompanied by other redox changes (see
P2eAu2eY
Au1/Au2b
C7eC6eC11eP2
C6eC11eP2eAu2
C5eC1eP1eAu1
P1eAu1/P2eAu2
FeeCg1
c
7.2537(2)
ꢀ94.4(4)
ꢀ62.4(3)
34.2(4)
97.40(4)
1.650(2)
1.648(2)
1.7(3)
d
text). In addition, an irreversible reduction is observed at Epc ¼ 0.795 V.
59.4(4)
ꢀ24.9(4)
104.51(5)
1.643(2)
1.648(2)
4.4(3)
99.66(4)
1.642(2)
1.648(2)
1.3(2)
2.3. Electrochemistry
FeeCg2
Anodic electrochemistry of compounds 1 and 3e7 was studied
by cyclic voltammetry at platinum disc electrode in dichloro-
methane solution containing 0.1 M Bu4N[PF6] as the supporting
electrolyte. Compound 8 could not be analyzed due to an insuffi-
cient solubility [30]. Pertinent data are presented in Table 2.
Free ligand 1 expectedly undergoes a single one-electron
oxidation attributable to the electrochemically reversible ferro-
cene/ferrocenium couple (Fig. 9). However, this redox event is
associated with chemical reactions, which make the overall redox
response quasi-reversible and produce some electroactive products
giving rise to additional waves at higher potentials. As a result, the
ratio of the anodic and cathodic peak currents (ipa/ipc) increases
tiltc
sd
88
76
75
70
a
Definition of the parameters: Cp1 ¼ C(1e5), Cp2 ¼ C(6e10). Cg1 and Cg2 are the
respective ring centroids.
b
Intramolecular distance Au1/Au2.
Dihedral angle of the least-squares planes of the cyclopentadienyl rings.
Torsion angle C1eCg1eCg2eC6.
Further data: C36eC37 1.203(8), Au1eC36eC37 173.3(5), C44eC45 1.186(4),
c
d
e
Au2eC44eC45 176.2(3).
f
Further data: Au1eS2 3.047(1), S1eAueS2 65.82(3), Au2eS4 2.918(1),
S3eAu2eS4 67.49(3), C36eS1 1.755(4), C36eS2 1.697(4), S1eC36eS2 119.7(2),
C36eN1 1.337(5), C41eS3 1.737(4), C41eS4 1.705(4), S3eC41eS4 119.0(2),
C41eN2 1.328(5).
g
Further data: S1eC36 1.822(4), C36eC37 1.519(5), C37eC38 1.506(5), S2eC38
with increasing scan rate (n; Fig. 9). Otherwise, the primary redox
change represents a standard diffusion-controlled process as indi-
1.836(4), Au1eS1eC36 108.7(1), S1eC36eC37 116.9(2), C36eC37eC38 113.6(3),
C37eC38eS2 114.8(3), C38eS2eAu2 108.1(1).
cated by the anodic peak current increasing with the square root of
½
the scan rate (ipa
f
n
).
molecule and its inversion-related image. However, the Au2/Au20
distance of 4.2162(3) Å exceeds the sum of the van der Waals radii,
which is in accordance with an unfavorable antiparallel orientation
of the PeAueCl units resulting from the imposed symmetry.
Such behavior is not unprecedented among ferrocene phos-
phines and has been attributed to the presence of the lone electron
pair at phosphorus as a reactive site [31]. After coordination to
metal center, this reactive site is no longer available, which natu-
rally simplifies the redox response. Indeed, the bis(chlorogold)
complex 3 undergoes a standard, reversible one-electron oxidation
(Fig. 9). Because of electron density transfer from the diphosphine
ligand to the metal centers, this oxidation is more difficult than in 1
Fig. 9. Cyclic voltammograms of compounds 1 and 3 as recorded in dichloromethane
Fig. 8. Partial packing diagram for 2 showing the shortest intermolecular Au/Au
contacts as red dotted lines. The hydrogen atoms were omitted for clarity. The inter-
atomic distances are as follows: Au1/Au10 ¼ 3.2502(2) Å, Au2/Au200 ¼ 4.2162(3) Å.
at Pt disc electrode. The scan rate (in mV sꢀ1) is given in parentheses. The voltam-
mogram of 3 is shifted by ꢀ5
m along the i-axis to avoid overlaps and the scan direction
is indicated with an arrow.

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115
and the ferrocene/ferrocenium wave appears shifted toward higher
potentials (by 0.33 V vs. 1) [32]. Complexes 4 and 6 featuring other
simple monoanionic ligands behave similarly (see Table 2).
The presence of redox-active pendant groups in 5 (FcC^C) is
noted by an additional reversible wave corresponding to two
electrons exchanged at a potential similar to unsubstituted ferro-
cene (Fig. 10) [33]. The fact that both pendant ferrocenyl groups are
oxidized in one step and that only a negligible change in the redox
potential of the central ferrocene unit is observed as compared to 4
[34] rule out any significant electronic communication between the
individual redox centers present in 5. Finally, the redox response of
compound 7 is complicated by additional redox changes (in addi-
tion to the FeII/III wave) occurring presumably at the non-innocent
dithiocarbamate ligands [35]. These redox processes generate
a species, which is irreversibly reduced at 0.795 V (Fig. 11).
3. Conclusion
Compound 3, readily prepared by the reaction of 1-(diphenyl-
phosphino)-10-[(diphenylphosphino)methyl]ferrocene
with
[AuCl(tht)], represents a good starting point for the synthesis of novel
trimetallic Au2Fe complexes via salt metathesis. It is noteworthy that
unlike many compounds obtained analogously from the commonly
used diphosphines (e.g., dppe or dppf), compound 3 and complexes
derived thereof are not symmetric (i.e., composed of two equivalent
parts) and thus suitable for investigation of the interactions between
the metal centers and possible structural changes associated with
modified structure by means of physicochemical methods and X-ray
crystallography, respectively.
Fig. 11. Cyclic voltammetric response 7 in “oxidation first” (top) and “reduction first”
(bottom) scans (in dichloromethane at Pt disc electrode, scan rate 200 mV sꢀ1). The
starting potential and the scan direction are indicated with a filled circle and an arrow,
respectively. In the “reduction first” scan (bottom), the second scan is shown by
a dashed line. The asterisk indicates peaks tentatively attributed to the FeII/III couple
(the ferrocene unit). The voltammograms are shifted along the vertical axis to avoid
overlaps.
NMR spectra were measured with a Varian UNITY Inova 400
spectrometer. Chemical shifts (d/ppm) are given relative to internal
4. Experimental
SiMe4 (1H and 13C) or to external 85% H3PO4 (31P). In addition to the
standard notation of signal multiplicity, vt and vq are used to denote
virtual multiplets arising from AA0BB0 and AA0BB0X spin systems of
the Ph2PCH2e and PPh2esubstituted cyclopentadienyl rings,
respectively (Fc ¼ ferrocenyl, fc ¼ ferrocene-1,10-diyl). IR spectra
were recorded with an FTIR Nicolet Magna 760 instrument. UVevis
spectra were recorded on a Unicam UV 300 spectrometer for ca.
2 ꢂ 10ꢀ5 M solutions in dry 1,2-dichlorethane (SigmaeAldrich,
absolute). Electrospray ionization (ESI) mass spectra were obtained
with a Bruker Esquire 3000 spectrometer. The samples were dis-
solved in a small amount of CH2Cl2 and then diluted with methanol
in a large excess.
4.1. Materials and methods
The syntheses were carried out under argon atmosphere and
with exclusion of direct daylight. [AuCl(tht)] [36], 1 [14], and
ethynylferrocene [37] were prepared according to the literature
procedures. Dichloromethane and chloroform were dried over
anhydrous potassium carbonate and distilled. Methanol was freshly
distilled from sodium methoxide. Other chemicals and solvents
used for crystallizations and chromatography were used as
received (Fluka, Aldrich; solvents from Lachner).
Electrochemical measurements were carried out with
a computer-controlled potentiostat
mAUTOLAB III (Eco Chemie,
Netherlands) at room temperature (ca. 23 ꢁC) using a Metrohm
three-electrode cell equipped with a platinum disc working elec-
trode (2 mm diameter), platinum sheet auxiliary electrode, and
a double-junction Ag/AgCl (3 M KCl) reference electrode. The
compounds were dissolved in dry dichloromethane (SigmaeAldrich,
absolute) to give a solution containing ca. 0.5e0.7 mM of the analyte
and 0.1 M Bu4N[PF6] (Fluka, puriss. for electrochemistry) as the
supporting electrolyte. The solutions were deaerated with argon
before the measurement and then kept under an argon blanket.
The redox potentials (accuracy ca. 5 mV) were recorded relative
to internal decamethylferrocene/decamethylferrocenium and then
converted to the ferrocene/ferrocenium scale by subtracting
0.548 V [38].
4.2. In situ NMR study of the reaction between 1 and [AuCl(tht)]
Ligand 1 (11.5 mg, 0.020 mmol) and [AuCl(tht)] (6.5 mg,
0.020 mmol; molar ratio P:Au ¼ 2:1) were dissolved in NMR grade
Fig. 10. Cyclic voltammogram of compound 5 (recorded in CH2Cl2 at Pt electrode, scan
rate 200 mV sꢀ1). The scan direction is indicated with an arrow.

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116
CDCl3 (ca. 0.6 mL). The resulting solution was stirred for 30 min and
analyzed by 1H and 31P{1H} NMR spectroscopy. The solid product,
which separated during storage of the reaction mixture at 4 ꢁC
overnight, was filtered off, washed with chloroform and dried
under vacuum to afford compound 2 as a fine yellow solid. Yield:
14.6 mg (86%).
([M ꢀ PhC^C]þ), 765 ([Au(1)]þ). Anal. calcd (%) for C51H40Au2
FeP2$1.8CHCl3 (1379.4): C 45.97, H 3.05; found: C 45.97, H 3.12.
-
4.5. Preparation of {m-1kP:2k
P0-1-(diphenylphosphino)-10-
[(diphenylphosphino)methyl]ferrocene}bis[(ferrocenylethynyl-k
C1)
gold(I)] (5)
In situ 1H NMR (400 MHz, CDCl3, 25 ꢁC):
d 1.94 (m, 4H, tht), 2.83
(m, 4H, tht), 3.75 (br s, 2H, CH2), 3.90 (br s, 2H, fc), 4.22 (br s, 2H, fc),
Ethynylferrocene (21 mg, 0.10 mmol) was dissolved in absolute
ethanol (3 mL) with gentle warming. The solution was cooled in ice
and then treated successively with 0.1 M NaOEt in ethanol (2 mL,
0.20 mmol) and a solution of 3$0.25CH2Cl2 (53 mg, 0.050 mmol) in
dry dichloromethane (3 mL). The cooling bath was removed and
the resulting cloudy yelloweorange mixture was stirred at room
temperature for 20 h and evaporated under vacuum. The orange
residue was taken up with dichloromethane (15 mL), the solution
was washed with water (3 ꢂ 10 mL), dried over MgSO4, and
evaporated. The solid residue was washed successively with diethyl
etherepentane (1:1, 10 mL) and pentane (2 ꢂ 10 mL), and dried
under vacuum. The crude product was dissolved in chloroform
(ca. 3 mL) and the solution was layered with absolute ethanol
(ca. 9 mL). Crystallization at 4 ꢁC for several days afforded a bright
orange solid, which was filtered off, washed with pentane and dried
4.32 (br s, 2H, fc), 4.61 (br s, 2H, fc), 7.32e7.69 (m, 20H, PPh2). In situ
31P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
calcd (%) for C35H30AuClFeP2$0.3CHCl3 (836.6): C 50.68, H 3.65;
found: C 50.43, H 3.64.
d
32.2, 37.0 (2ꢂ br s). Anal.
The reaction was performed also at P:Au molar ration of 1:1, i.e.,
with 13.0 mg (0.040 mmol) of [AuCl(tht)]. The 1H and 31P{1H} NMR
spectra of the reaction mixture revealed only the signals of complex
3 (see below) and free tht.
4.3. Preparation of {m-1kP:2k
P0-1-(diphenylphosphino)-10-
[(diphenylphosphino)methyl]ferrocene}bis[chlorogold(I)] (3)
A solution of 1 (57 mg, 0.10 mmol) in dichloromethane (3 mL)
was added to solid [AuCl(tht)] (64.5 mg, 0.20 mmol). The resulting
yelloweorange solution was stirred for 1 h and then precipitated
with pentane (ca. 30 mL). During subsequent storing at 4 ꢁC over-
night, the amorphous precipitate converted into a microcrystalline
solid, which was filtered off, washed with pentane and dried under
vacuum to afford 3$0.25CH2Cl2 as a bright yellow solid. Yield:
under vacuum. Yield of 5$0.2CHCl3: 60 mg (85%).
2
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d
3.57 (d, JPH ¼ 9.6 Hz, 2H,
CH2), 3.88 (vt, J0 ¼ 1.9 Hz, 2H, fc), 4.09 (vt, J0 ¼ 1.8 Hz, 2H, C5H4 of Fc),
4.11 (vt, J0 ¼ 1.9 Hz, 2H, C5H4 of Fc), 4.21 (s, 10H, C5H5 of Fc), 4.22 (m,
2H, fc), 4.27 (br vt, 2H, fc), 4.35 (vt, J0 ¼ 1.8 Hz, 2H, C5H4 of Fc), 4.44
(vt, J0 ¼ 1.9 Hz, 2H, C5H4 of Fc), 4.55 (br d of vt, J0 ¼ 0.9,1.9 Hz, 2H, fc),
7.36e7.81 (m, 20H, PPh2). 31P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
100 mg (95%).
2
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d
3.68 (d, JPH ¼ 10.6 Hz, 2H,
CH2), 3.88 (vt, J0 ¼ 1.9 Hz, 2H, fc), 4.21 (br d of vt, J0 z 0.5, 1.9 Hz, 2H,
fc), 4.24 (d of vt, J0 ¼ 3.1, 2.0 Hz, 2H, fc), 4.61 (m, 2H, fc), 7.38e7.84
d
37.6, 40.0 (2ꢂ s). MS (ESIþ): m/z 1380 (Mþ), 1403 ([M þ Na]þ),
1419 ([M þ K]þ), 1171 ([M ꢀ FcC^C]þ), 765 ([Au(1)]þ). Anal. calcd
(%) for C59H46Au2Fe3P2$0.2CHCl3 (1404.3): C 50.63, H 3.46; found: C
50.77, H 3.52.
(m, 20H, PPh2). 31P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
d
¼ 28.9, 33.6
(2ꢂ s). MS (ESIþ): m/z 1055 ([M þ Na]þ), 997 ([M ꢀ Cl]þ), 765
([Au(1)]þ). Anal. calcd (%) for C35H30Au2Cl2FeP2$0.25CH2Cl2
(1054.5): C 40.15, H 2.92; found: C 40.11, H 2.95.
4.6. Preparation of {m-1kP:2k
P0-1-(diphenylphosphino)-10-
[(diphenylphosphino)methyl]ferrocene}bis[(thiocyanato-kS)
gold(I)] (6)
4.4. Preparation of {
m
-1k
P:2
k
P0-1-(diphenylphosphino)-10-
[(diphenylphosphino)methyl]ferrocene}bis[(phenylethynyl-k
C1)
gold(I)] (4)
Aqueous KSCN (19.5 mg, 0.20 mmol in 5 mL) was added to
a solution of 3$0.25CH2Cl2 (53 mg, 0.050 mmol) in dry dichloro-
methane (3 mL) and the resulting mixture was stirred vigorously
for 18 h. The organic layer was separated and the aqueous phase
was extracted with dichloromethane (2 ꢂ 5 mL). Combined organic
layers were dried briefly over MgSO4 and evaporated under
vacuum. The residue was re-dissolved in dichloromethane (4 mL)
and the solution was added to cold pentane (40 mL). After standing
at 4 ꢁC overnight, the precipitated product was filtered off, washed
with pentane and dried under vacuum. Yield of 6: 42 mg (78%),
A solution of ethynylbenzene (10.5 mg, 0.10 mmol) in absolute
ethanol (3 mL) was treated with 0.1 M NaOEt in ethanol (2 mL,
0.20 mmol; prepared by dissolving sodium metal in absolute
ethanol) while stirring and cooling in an ice bath. After 5 min,
a solution of 3$0.25CH2Cl2 (53 mg, 0.050 mmol) in dry dichloro-
methane (3 mL) was introduced, the cooling bath was removed,
and the resulting cloudy yellow mixture was stirred at room
temperature for 20 h. Then, it was evaporated under vacuum to give
an orange residue, which was dissolved in dichloromethane
(15 mL). The solution was washed with water (3 ꢂ 10 mL), dried
over MgSO4, and evaporated. The solid residue was washed with
diethyl etherepentane (1:1, 10 mL) and pentane (2 ꢂ 10 mL), and
dried under vacuum. The crude product was dissolved in chloro-
form (ca. 3 mL) and the solution layered with absolute ethanol (ca.
7 mL). Subsequent crystallization by liquid-phase diffusion at room
temperature and then at ꢀ18 ꢁC over several days yielded an orange
yellow crystalline solid, which was filtered off, washed with
pentane and dried under vacuum. The crystals partly disintegrate
upon work-up due to a loss of the clathrated solvent. Yield of
yellow solid.
2
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d
3.61 (d, JPH ¼ 10.5 Hz, 2H,
CH2), 3.97 (vt, J0 ¼ 1.9 Hz, 2H, fc), 4.23 (d of vt, J ¼ 0.8, 1.9 Hz, 2H, fc),
4.30 (d of vt, J ¼ 3.0, 1.9 Hz, 2H, fc), 4.63 (d of vt, J ¼ 1.2, 1.8 Hz, 2H,
fc), 7.43e7.70 (m, 20H, PPh2). 31P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
d
33.7, 37.1 (2ꢂ s). MS (ESIþ): m/z 765 ([Au(1)]þ); IR (Nujol): nSCN
2120 s, 2076 m cmꢀ1. Anal. calcd (%) for C38H36Au2FeP2S2 (1068.5):
C 41.20, H 2.80, N 2.60; found: C 41.28, H 2.89, N 2.51.
4.7. Preparation of {
[(diphenylphosphino)methyl]ferrocene}bis[(N,N-diethylcarbamo
dithioato- S)gold(I)] (7)
m-1kP:2k
P0-1-(diphenylphosphino)-10-
4$1.8CHCl3: 45 mg (65%).
k
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d
3.72 (d, JPH ¼ 9.8 Hz, 2H,
2
CH2), 3.86 (vt, J0 ¼ 1.9 Hz, 2H, fc), 4.23 (d of vt, J ¼ 2.8, 2.0 Hz, 2H, fc),
Aqueous solution of NaS2CNEt2$3H2O (25 mg, 0.110 mmol in
5 mL) was added to a solution of 3$0.25CH2Cl2 (53 mg, 0.050 mmol)
in dichloromethane (5 mL), and the resulting heterogeneous
mixture was vigorously stirred for 3 h. The organic layer was
4.32 (br vt, 2H, fc), 4.57 (d of vt, J z 1.0, 1.8 Hz, 2H, fc), 7.16e7.89
(m, 30H, PPh2). P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
d 37.6, 40.3
31
(2ꢂ s). MS (ESIþ): m/z 1380 (Mþ), 1187 ([M þ Na]þ), 1063

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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
117
separated, washed with water (2 ꢂ 2 mL), shortly dried over MgSO4
and evaporated. The residue was dissolved in dichloromethane
(4 mL), treated with little charcoal, and filtered into pentane
(40 mL). After standing at 4 ꢁC overnight, the precipitated solid was
filtered off and dried under vacuum to give 7 as a yellow solid.
Yield: 52 mg (83%). Subsequent crystallization from
fc), 4.27 (d of vt, J ¼ 2.9, 1.9 Hz, 2H, fc), 4.47 (br vt, J0 z 1.7 Hz, 2H, fc),
4.51 (d of vt, J z 1.0,1.8 Hz, 2H, fc), 7.23e7.72 (m, 20H, PPh2). 31P{1H}
NMR (162 MHz, CDCl3, 25 ꢁC):
d
34.6, 37.7 (2ꢂ s). MS (ESIþ): m/
z ¼ 1069 ([M þ H]þ),1091 ([M þ Na]þ), 765 ([Au(1)]þ). Anal. calcd (%)
for C38H36Au2FeP2S2 (1068.5): C 42.71, H 3.40; found: C 42.35, H 3.19.
chloroformehexane afforded the stoichiometric solvate 7$CHCl3.
4.9. X-ray crystallography
3
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d
1.32 (t, JHH ¼ 7.1 Hz, 12H,
NCH2CH3), 3.63 (d, 2JPH ¼ 10.0 Hz, 2H, CH2), 3.86 (vt, J0 ¼ 1.9 Hz, 2H,
fc), 3.93 (q, 3JHH ¼ 7.1 Hz, 8H, NCH2CH3), 4.33 (d of vt, J0 z 2.9,1.8 Hz,
2H, fc), 4.41 (br d of vt, J0 z 0.7, 2.0 Hz, 2H, fc), 4.53 (m, 2H, fc),
7.33e7.89 (m, 20H, PPh2). 31P{1H} NMR (162 MHz, CDCl3, 25 ꢁC):
Single-crystals suitable for X-ray diffraction measurements
were grown by liquid-phase diffusion from 1,2-dichloroethane-
diethyl ether (3$½C2H4Cl2: yellow block, 0.30 ꢂ 0.35 ꢂ 0.40 mm3;
8: yellow plate, 0.15 ꢂ 0.18 ꢂ 0.20 mm3), chloroformeethanol
31.6, 34.8 (2ꢂ s); MS (ESIþ): m/z 1110 ([M ꢀ Et2NCS2]þ). Anal.
(4$2CHCl3: yellow prism, 0.03
ꢂ
0.13
(7$2CHCl3:
ꢂ
0.25 mm3), and
yellow plate,
d
calcd (%) for C45H50Au2FeN2P2S4$CHCl3 (1378.2): C 40.09, H 3.73, N
from
chloroformepentane
0.08 ꢂ 0.12 ꢂ 0.37 mm3).
2.03; found: C 40.17, H 3.76, N 1.97.
Full-set diffraction data (ꢄh ꢄ k ꢄ l, 2
q
ꢅ 55ꢁ; completeness
4.8. Preparation of {
[(diphenylphosphino)methyl]ferrocene}{
m
-1
k
P:2
k
P0-1-(diphenylphosphino)-10-
ꢃ99.7%) were collected with a Bruker Apex2 or a Nonius KappaCCD
m-1kS:2
k
S0-propane-1,3-
diffractometer equipped with Cryostream cooler (Oxford Cry-
dithiolato}digold(I) (8)
osystems) using graphite-monochromated Mo Ka radiation
(
l
¼ 0.71073 Å). The data were corrected for absorption by methods
Methanolic solution of sodium methoxide (1.1 mL 0.10 M,
0.11 mmol) was added to a solution of propane-1,3-dithiol (14 mg,
0.13 mmol) in the same solvent (10 mL). The mixture was stirred for
ca. 5 min and then added drop-wise to a solution of 3$0.25CH2Cl2
(53 mg, 0.050 mmol) in dichloromethane (10 mL) while stirring and
cooling in ice. During the addition, the mixture became opaque. The
cooling was removed and stirring was continued at room temper-
ature for 20 h. The volatiles were removed under vacuum, and the
yellow solid residue was partitioned between dichloromethane and
water (20 mL each). The yellow organic extract was separated, dried
over MgSO4 and evaporated. The residue was taken up with chlo-
roform (3 mL) and the solution layered with ethanol (8 mL). Crys-
tallization by liquid-phase diffusion over several days afforded
well-developed orange crystals, which were filtered off, washed
with ethanol and dried under vacuum. Yield of 8: 34 mg (64%),
orange crystalline solid.
included in the diffractometer software. Selected crystallographic
data are summarized in Table 3.
The phase problems were solved by direct methods (SIR-97 [39]
or SHELXS-97 [40]), and the structure models were refined by full-
matrix least-squares based on F2 (SHELXL-97 [40]). Unless specified
otherwise, the non-hydrogen atoms were refined with anisotropic
displacement parameters. The hydrogen atoms were included in
their calculated positions and refined as riding atoms (SHELXL-97).
One of the peripheral phenyl groups in the structure of compound
4$2CHCl3 was found to be disordered (slightly bent from the axis of
the pivotal triple bond and rotated). It was modeled over two
positions and refined with isotropic displacement parameters for
the ring carbon atoms. Relative occupancies of the two contributing
parts were refined to ca. 0.56 and 0.44.
All geometric calculations were performed with a recent version
of PLATON program [41], which was also used to draw the Figures.
All numerical values are rounded with respect to their estimated
standard deviations given with one decimal.
1H NMR (400 MHz, CDCl3, 25 ꢁC):
d 2.51 (m, 2H, SCH2CH2), 2.79 (d,
2JPH ¼ 10.1 Hz, 2H, CH2), 3.24 (br s, 4H, SCH2), 4.18 (vt, J0 ¼ 1.9 Hz, 2H,
Table 3
Crystallographic data, data collection and structure refinement parameters for 3$½C2H4Cl2, 4$2CHCl3, 7$2CHCl3, and 8.a
Compound
3$½C2H4Cl2
36H32Au2Cl3FeP2
1082.69
4$2CHCl3
7$2CHCl3
8
Formula
M
C
C53H42Au2Cl6FeP2
1403.29
C47H52Au2Cl6FeN2P2S4
1497.57
C38H36Au2FeP2S2
1068.51
Crystal system
Space group
a (Å)
b (Å)
c (Å)
Monoclinic
C2/c (no. 15)
13.7584(2)
17.3175(2)
29.6625(3)
Triclinic
Triclinic
Monoclinic
P21/n (no. 14)
12.0071(1)
16.2432(3)
18.1711(3)
Pe1 (no. 2)
11.7993(1)
13.1519(1)
18.1798(2)
85.2662(5)
76.1081(5)
67.4502(5)
2529.16(4)
2
6.485
0.202e0.544
99,056
11,649
10,021
Pe1 (no. 2)
11.9439(2)
13.2821(2)
18.6206(3)
87.5073(9)
74.4927(7)
70.7019(9)
2683.23(7)
2
6.270
0.196e0.590
54,088
12,271
10,218
a
b
g
(ꢁ)
(ꢁ)
(ꢁ)
94.0822(7)
105.357(1)
V (Å3)
7049.5(2)
8
9.053
0.083e0.173
57,543
8096
7123
8.43
3.22
3.89, 8.25
2.12, ꢀ1.97
3417.45(9)
4
9.227
0.206e0.346
54,087
7841
6469
5.65
2.58
3.73, 5.69
0.87, ꢀ1.53
Z
m
Tb
(Mo K
a
) (mmꢀ1
)
Diffrns collected
Independent diffrns
Observedc diffrns
Rintd (%)
6.63
3.15
4.02, 8.14
1.76, ꢀ2.37
4.49
2.72
3.96, 5.74
1.54, ꢀ1.27
R observed diffrnsc,d (%)
R, wRd all data (%)
Dr (e Åꢀ3
)
a
Common details: T ¼ 150(2) K.
b
c
The range of transmission factors.
I > 2s(I).
P
P
d
Definitions: Rint
¼
jFo2 ꢀ Fo2ðmeanÞj= Fo2, where Fo2 (mean) is the average intensity of symmetry-equivalent diffractions.
R
¼
SrrFor
ꢀ
rFcrr/SrFor,
P
P
wR ¼ ½ fwðFo2 ꢀ Fc2Þ2g= wðFo2Þ2Sꢆ1=2
:

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118
P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
(n) J.D.E.T. Wilton-Ely, A. Schier, N.W. Mitzel, H. Schmidbaur, J. Chem. Soc.
Dalton Trans. (2001) 1058e1062;
Acknowledgements
(o) J.D.E.T. Wilton-Ely, A. Schier, N.W. Mitzel, S. Nogai, H. Schmidbaur,
J. Organomet. Chem. 643e644 (2002) 313e323;
(p) V.W.-W. Yam, K.-L. Cheung, E.C.-C. Cheng, N. Zhu, K.-K. Cheung, Dalton
Trans. (2003) 1830e1835;
(q) L. Song, S.-Q. Xia, S.-M. Hu, S.-W. Du, X.-T. Wu, Polyhedron 24 (2005)
831e836;
(r) W. Henderson, B.K. Nicholson, E.R.T. Tiekink, Inorg. Chim. Acta 359 (2006)
204e214;
This work was financially supported by the Czech Science
Foundation (project no. P207/10/0176) and is a part of the long-
term research plan of the Faculty of Science, Charles University in
Prague supported by the Ministry of Education, Youth and Sports of
the Czech Republic (project no. MSM0021620857).
(s) P. Teo, L.L. Koh, T.S.A. Hor, Chem. Commun. (2007) 2225e2227;
(t) M. Ferrer, A. Gutierrez, L. Rodriguez, O. Rossell, J.C. Lima, M. Font-Bardia,
X. Solans, Eur. J. Inorg. Chem. (2008) 2899e2909;
(u) E.R. Knight, N.H. Leung, A.L. Thompson, G. Hogarth, J.D.E.T. Wilton-Ely,
Inorg. Chem. 48 (2009) 3866e3874.
Appendix A. Supporting material
CCDC 879017 (for 3$½C2H4Cl2), 879018 (for 4$2CHCl3), 879019
(for 7$2CHCl3) and 879020 (for 8) contain the supplementary
crystallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
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8 does not dissolve appreciably in
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V was observed upon going from dppf to
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P. Stepnicka, I. Císarová / Journal of Organometallic Chemistry 716 (2012) 110e119
119
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