Synthesis, solid state structure and spectro-electrochemistry of ferrocene-ethynyl phosphine and phosphine oxide transition metal complexes

Article abstract of DOI:10.1016/j.jorganchem.2008.11.046

The synthesis of ferrocene-ethynyl phosphine platinum dichloride complexes based on (FcC{triple bond, long}C)_nPh_3-nP (1a, n = 1; 1b, n = 2; 1c, n = 3; Fc = ferrocenyl, (η⁵-C₅H₅)(η⁵-C_5<

Full text of DOI:10.1016/j.jorganchem.2008.11.046

Journal of Organometallic Chemistry 694 (2009) 655–666
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis, solid state structure and spectro-electrochemistry of
ferrocene-ethynyl phosphine and phosphine oxide transition metal complexes
Alexander Jakob a, Petra Ecorchard a, Michael Linseis b, Rainer F. Winter b, Heinrich Lang a,
*
a Technische Universität Chemnitz, Fakultät für Naturwissenschaften, Institut für Chemie, Lehrstuhl für Anorganische Chemie, Straße der Nationen 62, 09111 Chemnitz, Germany
b Universität Regensburg, Institut für Anorganische Chemie, Universitätsstraße 31, 93040 Regensburg, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of ferrocene-ethynyl phosphine platinum dichloride complexes based on (FcC„C)nPh3ꢀn
P
(1a, n = 1; 1b, n = 2; 1c, n = 3; Fc = ferrocenyl, (g g
5-C5H5)( 5-C5H4)Fe) is described. Air-oxidation of 1c
Received 4 September 2008
Received in revised form 10 November 2008
Accepted 21 November 2008
Available online 30 November 2008
afforded (FcC„C)3P@O (6). Treatment of 1a–1c with [(PhC„N)2PtCl2] (2) or [(tht)AuCl] (tht =
tetrahydrothiophene) (7), respectively, gave the heterometallic transition complexes cis-[((FcC„C)n
Ph3ꢀnP)2PtCl2] (3a, n = 1; 3b, n = 2; 3c, n = 3) or [((FcC„C)nPPh3ꢀn)AuCl] (8a, n = 1; 8b, n = 2). Further
treatment of these molecules with HC„CMc (4a, Mc = Fc; 4b, Mc = Rc = (g g
5-C5H5)( 5-C5H4)Ru) in the
Dedicated to Prof. Dr. Otto J. Scherer on the
occasion of his 75th birthday.
presence of [CuI] produced trans-[((FcC„C)Ph2P)2Pt(C„CFc)2] (5) (reaction of 3a with 4a) and
[(FcC„C)nPh3ꢀnPAuC„CMc] (n = 1: 9a, Mc = Fc; 9b, Mc = Rc; n = 2: 11a, Mc = Fc; 11b, Mc = Rc) (reaction
of 4a, 4b with 8a, 8b), respectively.
Keywords:
The structures of 3a, 5, 6, 8, 9a, and 9b in the solid state were established by single-crystal X-ray struc-
ture analysis. The main characteristic features of these molecules are the linear phosphorus–gold–acet-
ylide arrangements, the tetra-coordination at phosphorus and the square-planar surrounding at
platinum.
Ferrocene
Phosphine alkynyls
Heteromultimetallic
Spectro-electrochemistry
The electrochemical and spectro-electrochemical behavior of complexes 5, 8a, 9a, 9b and
[(Ph3P)AuC„CFc] was investigated in the UV/Vis/NIR. Near IR bands that are likely associated with
charge transfer from the ((FcC„C)Ph2P)2Pt or the ((FcC„C)nPh3ꢀnP)Au (n = 0, 1) moieties appear upon
oxidation of the
rocene-ethynyl substituents on the phosphine coligands are oxidized.
Ó 2008 Elsevier B.V. All rights reserved.
r-bonded ferrocene-ethynyl groups. These bands undergo a (stepwise) blue shift as fer-
1. Introduction
linking of such a modularly constructed sandwich building block
allows the synthesis of heteromultimetallic ferrocenyl-containing
assemblies in which the appropriate transition metal atoms are
connected by carbon-rich organic and/or inorganic bridging moie-
ties [4]. Promising members of this family of compounds are the
Ferrocene is an exceptional building block to be incorporated in
multimetallic transition metal complexes since it can act as a re-
dox-label, one-electron reservoir and at the same time is a very ro-
bust compound [1]. Such assemblies provide interesting electronic,
optical and/or magnetic properties [1,2]. One class of electron-rich
sandwich complexes are ferrocenes containing exocyclic phos-
phine, phosphine chalcogenide or amine groups [3]. The electro-
chemically best studied candidate of this class of compounds is
(ferrocene-ethynyl)phosphines (FcC„C)nPh3ꢀnP (n = 1, 2, 3), a
hitherto only barely described class of molecules [5].
We report here on the synthesis, properties and the character-
ization of several platinum and gold (ferrocene-ethynyl)phosphine
complexes. The spectro-electrochemical behavior of some trime-
tallic gold complexes and of a pentametallic platinum complex is
also reported.
(diphenylphosphino)ferrocene,
Ph2PFc
(Fc = (g -
5-C5H5)(g5
C5H4)Fe) [3]. Very recently, Kirss and Geiger reported about the
anodic electrochemistry of phosphines and phosphine chalcoge-
nides containing two or three ferrocenyl organometallic entities
in weakly nucleophilic electrolytes [3]. In addition to the study of
their redox behavior species of this kind are interesting building
blocks for coordination compounds of higher nuclearity, due to
the presence of the phosphine unit. Coordinative and/or covalent
2. Results and discussion
The synthesis of transition metal complexes in which
(FcC„C)nPh3ꢀnP units (1a, n = 1; 1b, n = 2; 1c, n = 3) are connected
to a PtCl2 core, as given in cis-[((FcC„C)nPh3ꢀnP)2PtCl2] (n = 1, 3a;
n = 2, 3b; n = 3, 3c), is presented in Scheme 1.
Reacting two equivalents of 1a–1c with [(PhC„N)2PtCl2] (2)
produced the multi(ferrocene-ethynyl)phosphine platinum(II)
* Corresponding author. Tel.: +49 371 531 21210; fax: +49 371 531 21219.
E-mail address: heinrich.lang@chemie.tu-chemnitz.de (H. Lang).
0022-328X/$ - see front matter Ó 2008 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2008.11.046

656
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
CH2Cl2
-2 PhC
phine platinum units in which the Pt–Cl bonds are likewise trans
Pt
Ph3-n
P
PhC
N
Cl2
cis-
2
FcC
C
+
FcC C Ph3-n
n
P Pt
Cl2
2
2
N
positioned to a phosphorus donor atom of high trans-influence
[6]. The phosphorus–carbon distances (1.726(4)–1.752(4) Å) as
well as the C„C bond lengths (1.191(5)–1.198(5) Å) are in the typ-
ical range for this type of fragments [5,7]. As is characteristic of
other ferrocene complexes the Fe–D separations (D = centroid of
C5H5 and C5H4 units) range from 1.6406(2) to 1.6609(2) Å [8].
n
2
1a, n = 1
1b,n = 2
1c, n = 3
3a, n = 1 [5a]
3b,n = 2
3c, n = 3
Fc =
Fe
Scheme 1. Synthesis of phosphine platinum complexes 3a–3c.
0
0
Based on the torsion angles Csp–CCp–Fe–CCp , whereby CCp was se-
lected for the minimum resulting angle, eclipsed (torsion angle:
C14–C15–Fe2–C20 = 7.7(4)°, C26–C27–Fe3–C32 = 8.5(4)°, C50–
C51–Fe5–C56 = 9.0(4)°, and C62–C63–Fe6–C68 = 10.5(4)°) and
staggered (torsion angle: C2–C3–Fe1–C8 = 20.8(4)° and C38–C39–
Fe4–C44 = 18.6(4)°) conformations are typical.
chlorides 3a–3c in dichloromethane at ambient temperature in
high yield. They can easily be isolated as analytically pure samples
upon concentration of the reaction solutions and addition of petro-
leum ether, whereby the title compounds precipitate as orange sol-
ids. Single crystals of 3c could be grown by diffusion of n-pentane
into dichloromethane solutions containing 3c at 25 °C.
The structure of 3c in the solid state is depicted in Fig. 1. Rele-
vant bond distances (Å) and angles (°) are listed in Table 1. The
crystal and structure refinement data are presented in Table 6 (Sec-
tion 4).
The 1H, 13C{1H}, 31P{1H} NMR and IR spectroscopic data are in
agreement with the composition of the appropriate complexes
and show no distinctive features compared with the systems dis-
cussed earlier (Section 4). The J(31P–195Pt) coupling constants of
3760 (3a), 3886 (3b), and 4029 Hz (3c) found in the 31P{1H} NMR
spectra confirm that cis-configurated platinum complexes were
formed [5,9]. X-ray single-crystal structure determination of 3c
confirms this structural arrangement (vide supra).
ꢀ
Complex 3c crystallized in the monoclinic space group P1. The
structure of 3c in the solid state shows a somewhat distorted
square-planar coordination geometry at Pt1 with cis-oriented
(FcC„C)3P units (r.m.s. deviation of fitted atoms 0.0625 Å). The an-
gles P1–Pt1–Cl2 and P2–Pt1–Cl1 in 3c are almost linear at
175.58(4) and 173.35(4)°. The Pt–P and Pt–Cl separations (Fig. 1)
agree well with those bond lengths reported for other chloro-phos-
Diphosphine platinum dichloride complexes are known to react
with 1-alkynes to produce (bis)alkynyl complexes [10]. Thus, treat-
ment of 3a with an excess of HC„CFc (4a) in the presence of [CuI]
in a diisopropylamine solution produced with concomitant precip-
itation of [H2NiPr2]Cl, orange trans-[((FcC„C)Ph2P)2Pt(C„CFc)2]
(5) in a 75% isolated yield (Reaction (1)).
2 HC CFc (4a)
HNiPr2, [CuI]
cis-
Ph2P
PtCl2
FcC
C
Ph2
P
C
2Pt C CFc
FcC
trans-
2
2
3a
5
ð1Þ
Fc =
Fe
Most noteworthy in the IR spectrum of 5 is the appearance of
two well-separated C„C stretching bands at 2162 and
2180 cmꢀ1 which can be assigned to the FcC„CPt and
(FcC„C)Ph2P moieties (Section 4).
In the 31P{1H} NMR spectrum of 5 a sharp singlet is observed at
ꢀ7.3 ppm. Due to the coupling of the 31P nuclei with the 195Pt iso-
tope a J(31P–195Pt) coupling constant of 2765 Hz is found, which
proves that an isomerization from cis-3a to trans-5 has taken place
[11].
Single-crystal X-ray structure analysis was performed to con-
firm the molecular structure of 5 in the solid state. A view of this
molecule is shown in Fig. 2, while selected bond distances (Å)
and angles (°) are listed in Table 2. The crystal and structure refine-
ment data are summarized in Table 6 (Section 4).
Fig. 1. ORTEP diagram (50% probability level) of 3c with the atom-numbering
scheme. (Hydrogen atoms are omitted for clarity.)
The platinum metal atom is held in a distorted square-planar
environment (all atoms are perfectly in-plane) with the coordi-
nated (FcC„C)Ph2P units in a trans-position to each other (Fig. 2)
which is in accord with findings for other bis(alkynyl) complexes
of monodentate phosphines [12]. The platinum–carbon and plati-
num–phosphorus separations (Fig. 2) are within the range of re-
ported Pt–P and Pt–C bonds [12]. In addition, the carbon–carbon
distances of the appropriate acetylide ligands are typical of this
type of structural building blocks (Fig. 2) [12].
Table 1
Selected bond distances (Å) and angles (°) of complex 3c.
Bond distances
Pt1–Cl1
Pt1–Cl2
Pt1–P1
Pt1–P2
C1–C2
2.3362(10)
2.3501(11)
2.2152(11)
2.2290(11)
1.194(5)
C13–C14
C25–C26
C37–C38
C49–C50
C61–C62
1.192(5)
1.198(5)
1.198(5)
1.191(5)
1.192(5)
Bond angles
P1–Pt1–Cl2
P2–Pt1–Cl1
P1–Pt1–P2
Pt1–P1–C1
Pt1–P1–C13
Pt1–P1–C25
Pt1–P2–C37
Pt–P2–C49
While molecules 1a–1c are fairly stable in the solid state, they
slowly undergo oxidation at the phosphorus atom on exposure to
air to give the respective phosphine oxides (FcC„C)nPh3ꢀnP@O
(Section 4). Due to the superior electron richness 1c is easier oxi-
dized than 1a and 1b. Phosphine 1c is thus always contaminated
with trace amounts of (FcC„C)3P@O (6). This means that the more
ferrocene-ethynyl moieties are present, the more reactive the
complexes are. Heating 1c in tetrahydrofuran and bubbling air
175.58(4)
173.35(4)
93.85(4)
115.28(14)
118.50(14)
110.74(14)
118.25(14)
110.61(14)
Pt–P2–C61
P1–C1–C2
112.38(14)
174.6(4)
169.8(4)
167.6(4)
173.3(4)
172.3(4)
171.7(4)
P1–C13–C14
P1–C25–C26
P2–C37–C38
P2–C49–C50
P2–C61–C62

A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
657
separated pseudo-triplets at ca. 4.3 and 4.6 ppm with JHH coupling
constants of 1.9 Hz. The resonance signal for the C5H5 protons is
found at 4.25 ppm.
The identity of 6 was further confirmed by a single-crystal X-ray
diffraction study. A view of the molecule is given in Fig. 3. Selected
bond distances (Å) and angles (°) are given in Table 2, while the
crystal and structure refinement data are presented in Table 6 (Sec-
tion 4).
The overall structure of 6 is similar to those of related structur-
ally characterized ethynyl-functionalized phosphines and ferro-
cenes with a pseudo-tetrahedral surrounding at the phosphorus
atom [14]. Metrical parameters of molecule 6 are similar related
to those reported previously for comparable molecules [14]. The
phosphorus–carbon distances in
6 are 1.7431(18) (P1–C12),
1.7537(19) (P1–C24), and 1.7452(18) Å (P1–C36) indicating the
higher s orbital contribution of the phosphorus–acetylide P–C
bond, when compared with the P–Cphenyl unit. The cyclopentadi-
enyl rings are rotated by 8.62, 1.92 and 0.55° to each other which
is in accord with an almost eclipsed conformation.
The ferrocene-ethynyl phosphine complexes 1a–1c indepen-
dently synthesized by Baumgartner et al. [5a] and our group,
[5b] possess a lone pair of electrons at the phosphorus atom and
hence, should coordinate to 14–16 valence electron complex
fragments to form molecules of higher nuclearity. Exemplarily,
trimetallic Fe–Au–M complexes (M = Fe, Ru) of composition
Fig. 2. ORTEP diagram (50% probability level) of 5 with the atom-numbering
scheme. (Hydrogen atoms and the solvent molecule CH2Cl2 are omitted for clarity.)
[((FcC„C)Ph2P)AuC„CMc] (9a, Mc = (
g
5-C5H5)(
g
5-C5H4)Fe; 9b,
consecutive
Mc = ( a
g
5-C5H5)( 5-C5H4)Ru) were accessible in
g
reaction sequence by using (FcC„C)Ph2P (1a) as the key starting
material (Scheme 2).
Table 2
Selected bond distances (Å) and angles (°) of complexes 5 and 6.
Compound 1a reacts with [(tht)AuCl] (tht = tetrahydrothioph-
ene) (7), whereby 1a is added in a 25% excess in tetrahydrofuran
at 0 °C to give 8a. After column chromatography followed by crys-
tallization from dichloromethane-n-pentane mixtures molecule 8a
5
6
Bond distances
Pt1–P1
Pt1–C36
P1–C12
C11–C12
C35–C36
2.2923(9)
2.002(3)
1.753(4)
1.196(5)
1.203(5)
P1–O1
1.4685(16)
1.7431(18)
1.7537(19)
1.7452(18)
1.207(3)
P1–C12
P1–C24
P1–C36
C11–C12
C23–C24
C35–C36
1.203(3)
1.204(3)
Bond angles
P1–Pt1–C36
Pt1–P1–C12
Pt1–P1–C13
Pt1–P1C19
P1–C12–C11
C1–C11–C12
Pt1–C36–C35
C25–C35–C36
89.08(10)
115.66(12)
114.99
116.60(12)
1714(3)
176.6(4)
178.1(3)
175.9(4)
C11–C12–P1
C23–C24–P1
C35–C36–P1
C12–P1–C24
C24–P1–C36
C12–P1–C36
C12–P1–O1
C24–P1–O1
C36–P1–O1
171.17(16)
177.32(17)
168.67(16)
103.38(8)
101.94(9)
105.74(9)
115.26(9)
114.84(9)
114.18(9)
through the reaction solution gave orange 6 in quantitative yield
(Reaction (2)).
O
P
Fig. 3. ORTEP diagram (50% probability level) of 6 with the atom-numbering
scheme. (Hydrogen atoms are omitted for clarity.)
C
C
air
C
C
C
—
ð2Þ
—
(FcC C)3P
Fc
Fc
—
1 h, 40 °C, Thf
C
Fc
(Ph) P
C
C
(Ph)
2P AuCl
C
C
C
1c
2
[(tht)AuCl] (7)
Fe
6
Fe
Fe
0 ˚C, Thf
Compound 6 was characterized by elemental analysis, IR and
NMR spectroscopy. Characteristic features in the IR spectrum of
this compound are the C„C stretching vibration at 2150 cmꢀ1
and the m(P@O) absorption at 1254 cmꢀ1 [13]. The progress of the
oxidation of 1c can be monitored by the disappearance of the 31P
NMR signal at ꢀ88.9 ppm (1c) [5] and the appearance of a new sig-
nal at lower field (ꢀ66.8 ppm). The key spectroscopic 1H NMR fea-
ture is that the protons of the ferrocenyl C5H4 unit appear as two
1a
8a
(Ph) P Au
C
C
C
2
HC CMc (4a, 4b)
M
HNEt2, [CuI]
9a: M = Fe
9b: M = Ru
Scheme 2. Synthesis of 8a, 9a, and 9b from 1a (tht = tertrahydrothiophene).

658
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
could be isolated as an orange solid in 97% yield (Section 4). To
introduce a further transition metal fragment, heterodimetallic
lected bond lengths (Å) and angles (°) are given in Table 3. The
crystal and structure refinement data for these species are pre-
sented in Table 7 (Section 4).
8a was treated with HC„CMc (4a, Mc = (
g g
5-C5H5)( 5-C5H4)Fe;
4b, Mc = (
g
5-C5H5)( 5-C5H4)Ru) in diethylamine as solvent and
g
Complex 8a crystallized in the monoclinic space group P21/n.
The overall structural features of 8a are similar to those of related
(diphenyl)ferrocene-ethynyl phosphine and gold(I)–chloride-
containing compounds with gold in a linear arrangement and
phosphorus in a tetrahedral surrounding (Fig. 4). The cyclopentadi-
enyl rings of the Fc entity are rotated by 5.8° showing an almost
eclipsed conformation. The Au1–Cl1 and Au1–P1 distances agree
well with this type of bonds. [17] The same is true for the P1–
C12, P1–C13 and P1–C19 separations. The P1–C12 bond of
1.739(3) Å is expectedly shorter than the respective P1–C13
(1.815(3) Å) and P1–C19 (1.810(3) Å) distances (vide supra and
Fig. 4) [17].
Molecules 9a and 9b crystallized in the monoclinic space
groups P21/c (9a) and P21/a (9b). In both complexes the gold(I)
ion adopts the usual linear coordination [18]. The phosphorus
atom is tetra-coordinated, whereby two positions are occupied
by phenyl groups and the third and fourth coordination sites are
occupied by a C„CFc and a AuC„CFc (9a) or AuC„CRc (9b) unit
(Figs. 5 and 6). This coordination geometry is representative for
phosphines coordinated to a transition metal complex fragment
in the presence of catalytic amounts of [CuI] (Scheme 2). Following
the methodology reported by Vicente et al. orange 9a and 9b were
obtained in high yields [15].
Complexes 8a, 9a, and 9b are, when compared with the starting
material 1a, more difficult to dissolve. Complexes 9a and 9b, for
example, are only soluble in diethyl ether, tetrahydrofuran or
dichloromethane.
The synthesis methodology used in the preparation of 9a and 9b
should successfully be transferable to (FcC„C)2PhP (1b). Thus, this
compound was subsequently reacted with [(tht)AuCl] (7) in a 25%
excess of the phosphine to give the desired phosphine gold chlo-
ride coordination complex [((FcC„C)2PhP)AuCl] (8b) (Scheme 3).
Treatment of the latter molecule with McC„CH (4a, 4b) produced
[((FcC„C)2PhP)AuC„CMc] (11a, Mc = (
g g
5-C5H5)( 5-C5H4)Fe; 11b,
Mc = (g
5-C5H5)( 5-C5H4)Ru). These compounds could, however,
g
not be separated in pure form from the reaction mixtures.
The identities of 8a, 8b, 9a, and 9b have been confirmed by ele-
mental analysis, IR, 1H, 13C{1H}, and 31P{1H} NMR spectroscopy.
The consecutive preparation of higher nuclear heterometallic
assemblies from 1a and 1b are confirmed by 1H and 13C{1H}
NMR spectroscopic studies, since after each individual synthesis
step the newly introduced coordination or organometallic complex
fragments can be detected (Section 4). The spectroscopic proper-
ties of all new complexes correlate with their formulation as di-,
-tri- and tetrametallic transition metal systems showing the
respective signal patterns for the organic units (Section 4).
The 31P{1H} NMR spectra of 8 and 9 indicate the presence of a
single phosphorus environment with resonance signals at 1.9
(8a), ca. 15 (9a, 9b), and ꢀ37.5 ppm (8b). A shift to lower field oc-
curs upon coordination of the phosphorus atom to a AuCl moiety as
given in 8a and 8b [16]. Replacing the chloride ligand in 8a and 8b
by a C„CMc unit results in a further downfield shift (Section 4)
which is typical for phosphine gold(I) acetylides [16].
Most characteristic in the IR spectra of 8a, 8b, and 9a is the
appearance of only one C„C stretching vibration at ca. 2155
cmꢀ1 independent of the appropriate substitution pattern. How-
ever, this absorption is shifted to ca. 2167 cmꢀ1 when the
gold(I)-bonded FcC„C unit is replaced by a ruthenocene acetylide
moiety as given in 9b. Only one mC„C band was found for the two
different alkynyl entities, PC„CFc and AuC„CFc, in the IR spectra
of their coordination complexes.
Fig. 4. ORTEP diagram (50% probability level) of 8a with the atom-numbering
scheme. (Hydrogen atoms are omitted for clarity.)
In addition, the structures of 8a, 9a, and 9b in the solid state
were established by single X-ray structure analysis, thus confirm-
ing the assignments made from spectroscopic analysis. Suitable
single crystals of 8a, 9a, and 9b were obtained from slow vapor dif-
fusion of n-pentane into a dichloromethane solution containing the
appropriate transition metal complex at 25 °C. The molecular solid
state structures of 8a, 9a, and 9b are shown in Figs. 4–6, while se-
C
C PhP
PhP AuCl
C
C
[(tht)AuCl] (7)
Fe
Fe
Fe
0 ˚C, Thf
2
2
1b
8b
C
C PhP
Au
C C
HC CMc (4a, 4b)
M
HNEt2, [CuI]
2
11a, M = Fe;
11b, M = Ru
Fig. 5. ORTEP diagram (50% probability level) of 9a with the atom-numbering
Scheme 3. Synthesis of heterobi- and -trimetallic 8b, 11a, and 11b, respectively.
scheme. (Hydrogen atoms are omitted for clarity.)

A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
659
Table 4
Oxidation potentials of complexes [(Ph3P)AuC„CFc], 5, 8a, 9a, and 9b.a
Compound
E0 in V against the [Fc/Fc+] standard
ꢀ0.005
[(Ph3P)AuC„CFc]
5
8a
9a
9b
ꢀ0.150 (1 eꢀ), ꢀ0.055 (1 eꢀ), 0.24 (2 eꢀ)
ꢀ2.500, 0.350
0.000, 0.260
0.270b (2 eꢀ); 0.255c
Voltammograms were recorded in CH2Cl2/[nBu4N]PF6 (0.1 M) the supporting
a
electrolyte.
b
c
Partially reversible composite wave.
At ꢀ78 °C.
ethynyl moiety (E0 = ꢀ0.005 V for [(Ph3P)AuC„CFc]) compared to
the phosphine-bonded one (E0 = +0.350 V for 8a, Fig. 7).
Complex 9a combines both types of ferrocene-ethynyl subunits
(metal and phosphine-bonded) within the same molecule. As a
consequence, it shows two reversible one-electron waves at half-
wave potentials of 0.000 and +0.260 V vs. the ferrocene/ferroce-
nium standard (Fig. 8). With reference to [(Ph3P)AuC„CFc] and
[((FcC„C)PPh2)AuCl] (8a), respectively, the first wave can be as-
signed to the gold-bonded ferrocene-ethynyl group and the sec-
ond, more anodic one, to that of the (FcC„C)PPh2 ligand.
In contrast to 9a, where a ferrocene-ethynyl unit is present,
Fig. 6. ORTEP diagram (50% probability level) of 9b with the atom-numbering
scheme. (Hydrogen atoms and the solvent molecule dichloromethane are omitted
for clarity.)
complex 9b features a
r-bonded ruthenocene-ethynyl ligand.
Ruthenocenes are generally more difficult to oxidize than their iso-
structural ferrocene counterparts. Their associated radical cations
are highly electrophilic and readily react with even weak nucleo-
philes of the supporting electrolyte solution, which often renders
their oxidation irreversible [22,23]. Thus, an anodic shift of the
gold-bonded metallocene-ethynyl based oxidation wave is ex-
pected, when compared to 9a. In fact, complex 9b exhibits a par-
tially reversible composite wave at +0.27 V which is followed by
Table 3
Selected bond distances (Å) and angles (°) of complexes 8a, 9a, and 9b.
8a
9a
9b
Bond distances
Au1–P1
Au–Cl1
2.2188(7)
2.2863(6)
2.2779(11)
2.2577(17)
a
broader, smaller and irreversible peak at Ep = +0.62 V
(v =
0.1 V sꢀ1, Fig. 9a–c). Voltammograms recorded at = 20 mV sꢀ1
v
Au1–C25
P1–C12
P1–C13
P1–C19
C11–C12
2.000(5)
1.753(4)
1.838(5)
1.821(4)
1.196(6)
1.9841(19)
1.741(7)
1.833(7)
1.833(7)
1.196(9)
show that the main, less anodic wave comprises two separate elec-
tron transfer events as a shoulder appears on the rising part of the
forward peak of the more anodic, reversible feature. Upon increas-
ing the sweep rate the irreversible wave shifts anodically [24] to
the point, where both features merge into a single, partially revers-
ible composite wave with reverse-to-forward peak current ratios
ip,rev/ip,f in the range of 0.7–0.8 (Fig. 9a). With increasing sweep rate
the overall reversibility of the composite wave increases, while the
peak current ratio between the irreversible feature near 0.6 V and
the main peak diminishes somewhat (Fig. 9b). Cooling to ꢀ78 °C
renders the composite wave slightly more reversible and shifts
its half-wave potential to +0.255 V but again without discernible
resolution into separate features (Fig. 9c). This behavior can be
interpreted by the reversible oxidation of the ferrocene-containing
phosphine ligand and the partially reversible oxidation of the
ruthenocene-ethynyl substituent, [25–27] which occur fortu-
itously at very similar potentials. The irreversible peak near 0.6 V
arises from the further oxidation of the product that is formed on
the chemical degradation of the oxidized ruthenocene-ethynyl
moiety.
1.739(3)
1.815(3)
1.810(3)
1.202(4)
Bond angles
C11–C12–P1
P1–Au1–Cl1
P1–Au1–C25
C12–P1–C13
C12–P1–C19
C12–P1–Au1
C13–P1–Au1
C19–P1–Au1
Au1–C25–C26
168.7(2)
179.68(2)
176.8(4)
177.6(6)
174.24(12)
104.2(2)
103.8(2)
118.35(15)
110.39(17)
111.32(14)
175.0(4)
174.43(17)
104.9(3)
104.9(3)
110.0(2)
114.5(2)
116.4(2)
169.6(5)
103.83(12)
106.37(12)
114.35(9)
112.60(8)
114.83(9)
[16,18]. A comparison of the bond distances and bond angles in 9a
and 9b shows that they are in the same range of reported assem-
blies featuring ferrocene-/ruthenocene-ethynyl, gold(I) alkynyl
and PPh2 building blocks (vide supra) [19].
Voltammetric measurements on complexes 5, 8a, 9a, 9b and of
[(Ph3P)AuC„CFc] were performed in CH2Cl2/[nBu4N]PF6 as the
supporting electrolyte. Relevant data with potentials referenced
against the ferrocene/ferrocenium couple [20,21] are collected in
Table 4. Compounds [(Ph3P)AuC„CFc] and 8a feature one, 9a
and 9b two and 5 four redox-active metallocene-ethynyl moieties.
Complex 8a and [(Ph3P)AuC„CFc] help to establish the redox
properties of the differently bonded ferrocene-ethynyl entities
without possible interference from the other. Both complexes
undergo a single reversible one-electron oxidation with a signifi-
cantly lower oxidation potential for the gold-bonded ferrocene-
Complex 5 combines ferrocene-ethynyl substituents which are
-bonded to a phosphorus as well as a platinum atom and hence,
r
displays two pairs of reversible waves in the range of ꢀ0.2 to
+0.3 V (Fig. 10a). The first pair of waves clearly consists of two
overlapping, closely-spaced one-electron events that are resolved
as individual peaks in square wave voltammetry (Fig. 10 b). Half-
wave potentials as determined by deconvolution are ꢀ0.150 and
ꢀ0.055 V. With reference to 8a, 9a and [(Ph3P)AuC„CFc] these
waves can be assigned as the stepwise oxidation of the plati-
num-bonded ferrocene-ethynyl units. The oxidation of the

660
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
Fig. 7. Cyclic voltammograms of [(PPh3)AuC„CFc] (left) and 8a (right) (10ꢀ3 M solution in dichloromethane at 25 °C with [nBu4N]PF6 (0.1 M) as supporting electrolyte, scan
*
rate 0.10 V sꢀ1). All potentials are referenced to the [FcH/FcH+] redox couple (FcH = (
impurity.
g
5-C5H5)2Fe) with E0 = 0.00 V [24]. The wave indicated by the symbol represents an
Fig. 8. Cyclic voltammogram of complex 9a (10ꢀ3 M solution in dichloromethane at
25 °C with [nBu4N]PF6 (0.1 M) as supporting electrolyte, scan rate 0.10 V sꢀ1). All
potentials are referenced to the [FcH/FcH+] redox couple (FcH = ( 5-C5H5)2Fe) with
g
E0 = 0.00 V [24].
Fig. 10. (a) Cyclic voltammogram of complex 5 at
voltammogram at
= 25 Hz, step height = 4 mV (10ꢀ3 M solution in dichlorometh-
v
= 0.1 V sꢀ1; (b) square wave
m
ane at 25 °C with [nBu4N]PF6 (0.1 M) as supporting electrolyte). All potentials are
g
referenced to the [FcH/FcH+] redox couple (FcH = ( 5-C5H5)2Fe) with E0 = 0.00 V
[24].
(FcC„C)PPh2 moieties, however, occurs as a single wave or peak at
E0 = +0.24 V with the net transfer of two-electrons.
Some findings to support the idea that electronic information is
conjugatively transmitted along the
p-conjugated MC„CFc chain
are: (i) The half-wave potentials of the ferrocene-ethynyl-based
waves in [(Ph3P)AuC„CFc], 5 and 9a are considerably lower than
in parent ethynylferrocene (+0.16 V under our conditions)
[28,29]. This reflects the electron donation by the
r-bonded
((FcC„C)Ph2P)2Pt (5), (Ph3P)Au or ((FcC„C)Ph2P)Au (9a) units.
Similar observations have been reported for a variety of other het-
erobimetallic ferrocene-ethynyl complexes of platinum [30], gold
[31], iron [22–33], and ruthenium [31,33–36]. (ii) The oxidation
potential of
5 g
is lower than that in [(Tpind)Ru( 5-C5(C6H4-
4-C„C-Pt(PEt3)2-C„CFc)5)] (0.15 V, Tpind = tris(indazolyl)borate)
with a less electron donating alkynyl ligand trans to the ferro-
cene-ethynyl moiety [37] but close to complexes trans-
[Pt(C„CFc)(C6H4-4-X)(PPh3)2] (X = H, Me, OMe, Cl, COMe, CO2Me)
[30,38] and trans- [(Ph3P)2Pt(C„CFc)2] (ꢀ0.07 and 0.19 V),
respectively [38].
Previous work on heterobimetallic complexes of type
Fig. 9. Cyclic voltammograms of 9b. (a) Scans over the first composite wave at
sweep rates of 0.02, 0.1, and 0.2 V sꢀ1 at 25 °C; (b) scans at 25 °C over a wider
[MC„CMc]+ (Mc = Fc, Rc) featuring
r-bonded metallocene-ethy-
potential range to include the oxidation of the follow product at
v = 0.05, 0.2, 0.5,
nyl moieties has disclosed that their singly oxidized radical cations
generally display characteristic low energy absorptions in the vis-
ible or in the near infrared that are associated with the transfer of
electron density from the reduced electron-rich M donor to the
and 1.0 V sꢀ1; (c) scan at
v
= 0.2 V sꢀ1 after cooling to ꢀ78 °C (10ꢀ3 M solution in
dichloromethane at 25 °C with [nBu4N]PF6 (0.1 M) as supporting electrolyte). All
potentials are referenced to the [FcH/FcH+] redox couple (FcH = ( 5-C5H5)2Fe) with
g
E0 = 0.00 V [24].

A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
661
Table 5
Deconvoluted band maxima for [(Ph3P)AuC„CFc], 5, 9a, and 9b in their various
oxidation states.
Compound
kmax in nm according to spectral deconvolutiona
[(Ph3P)AuC„CFc]
446, 356, 334
[(Ph3P)AuC„CFc+]
855, 755, 560, 500, 410
480, 440, 356, 322
850, 760, 560, 500, 415
805, 700, 560, 460
470, 425, 360, 317
700, 605, 475, 408
470, 422, 386, 333
1013, 444, 329
9a
[9a]Å+
[9a]2+
9b
[9b]2+
5
[5]Å+
[5]2+
[5]4+
975, 885, 575, 452, 360
951, 755, 572, 450, 360
a
Similarly good fits were obtained with somewhat different parameter sets. The
error in kmax is 5 nm for the higher and 10 nm for the lower energy absorption of
the oxidized forms.
oxidized Mc+ acceptor site [28,30,32,34–37,39]. We have probed
for the occurrence of similar bands in [(Ph3P)AuC„CFc] and 9a,
9b, and 5 by means of in situ UV/Vis/NIR spectro-electrochemistry.
The results of these investigations are summarized in Table 5. Be-
*
*
sides the intense n ?
p and p ? p type transitions of the ferroce-
nyl and the Ph3P moieties in the UV, compound [(Ph3P)AuC„CFc]
has a weaker, broad and asymmetric electronic absorption peaking
at 446 nm associated with the AuC„CFc moiety. Oxidation of the
ferrocene-ethynyl moiety induces the growth of a new composite
low energy absorption band with (deconvoluted) peak maxima of
855 and 755 nm and band widths of about 1550 and 2550 cmꢀ1
.
Higher energy absorptions include weaker bands at 560 and
500 nm and a stronger absorption at 410 nm (Fig. 11).
The spectra of neutral 9a and of monooxidized [9a]Å+ with the
same oxidized Fc+C„CAu unit as in [(Ph3P)AuC„CFc]+ closely
resemble the ones observed for the simpler PPh3 ligated compound
in its respective oxidation state (Table 5, Fig. 12a) with a composite
low-energy band with deconvoluted peak maxima of 850 and
760 nm, weaker bands at 560 and 500 nm and a stronger absorp-
tion at 415 nm. Upon the second, (FcC„C)Ph2P-based oxidation
to [9a]2+ the low energy bands intensify and experience a blue shift
of about 700 and 900 cmꢀ1 to 805 and 700 nm (Fig. 12b). This blue
shift probably reflects the lowering of the ((FcC„C)Ph2P)Au-based
Fig. 12. Spectroscopic changes upon stepwise oxidation of 9a (1,2-C2H4Cl2/
[nBu4N]PF6) in an OTTLE cell. (a) Spectroscopic changes upon the first oxidation
to [9a]Å+, (b) the second oxidation to [9a]2+
.
thin-layer conditions of in situ spectro-electrochemistry. Spectra
obtained after a full oxidation/reduction cycle were very similar
to those of pristine 9b. Characteristic bands of oxidized 9b (which
is probably present as [9b]2+) appear at 700 and 605 nm, and thus
at higher energies as in the ferrocene-ethynyl counterpart [9a]2+
.
These differences may relate to the well-known propensity of oxi-
dized ruthenocene-ethynyls to rearrange to cyclopentadienylidene
type structures [25–27].
The resolved, stepwise oxidations of the platinum-bonded
C„CFc moieties of complex 5 raise the question whether they
are electronically coupled across the platinum center or not. While
(R3P)2Pt entities are usually regarded as insulating [30,40,41],
donor orbitals as
a consequence of the oxidation of the
(FcC„C)Ph2P ligand. The latter event is expected to increase the
energy of the (RPh2P)Au ? C„CFc+ charge-transfer (CT) transition.
The ruthenocene analog 9b, despite its only partially reversible
behavior in cyclic voltammetry, gave still useful results under the
some accounts of p-delocalization along the RC„C–Pt–C„CR axis
in trans-dialkynyl platinum complexes have already appeared
[38,39,42–44].
Such an ‘‘electronic coupling” should give rise to a low-energy
absorption band at the mixed-valent [5]Å+ state but not in the bor-
dering 5 and [5]2+ states, where both C„CFc moieties are present in
either their reduced or oxidized states. The analysis of the elec-
tronic spectra of [5]Å+ is, however, complicated by the proximity
of the two PtC„CFc-based oxidation waves. The 0.095 V splitting
of half-wave potentials translates via Eq. (1) into a comproportion-
ation constant of 40 for the intermediate mono-cation. In Eq. (3), n
denotes the number of transferred electrons, F is Faraday’s con-
stant, and R and T have their usual meaning.
½5ꢁ2þ þ ½5ꢁ ¢ 2½5ꢁþ; Kcomp ¼ exp½n ꢂ F ꢂ
D
E0=ðR ꢂ TÞꢁ
ð3Þ
In such a constellation, spectra recorded at any stage during the
first two oxidations represent mixtures of neutral 5, monoxidized
[5]Å+ and [5]2+ (Fig. 13a and b). From the spectra of neutral 5 and
Fig. 11. Spectroscopic changes upon oxidation of [(Ph3P)AuC„CFc] (1,2-C2H4Cl2/
[nBu4N]PF6) in an OTTLE cell.

662
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
Fig. 14. Calculated spectrum of singly oxidized [5]Å+
.
According to Eq. (4), the band maximum of a charge transfer
band in a heterobimetallic, (formally) mixed-valent system de-
pends on the redox asymmetry between the dislike redox sites.
This is expressed by the energy difference D
Gꢃ between the differ-
ent valence tautomers (MC„CFc+ and M+C„CFc), while k repre-
sents the reorganization energy. Further examples within the
context of MC„CMc+ systems have been reported by Sato et al.
[30,32,36,39].
D
Gꢃ
ð4Þ
~
mmax ¼ k þ
The blue shift of the relevant low-energy absorption band upon
replacement of Pt(PPh3)2(C„CFcn+ (n = 0, 5; n = 1: [5]Å+) by
)
Au(PR2R’) moieties (R0 = Ph or C„CFcn+ (n = 0, [9a]Å+; n = 1: [9a]2+
)
and upon the oxidation of ferrocene-ethynyl substituents at the
phosphine co-ligand is understandable on that basis. Also
pertinent to the systems in the current study are complexes
trans-[FcC„CPt(PPh3)2(C6H4-4-X)], where the PtC„CFc+ band sys-
tematically blue shifts as the rpþ parameter of the para-substituent
X increases. [30] Our value of 9870 cmꢀ1 (1013 nm) for [5]Å+
slightly exceeds those observed for the above aryl complexes
(9300–9480 cmꢀ1). The [(FcC„C)Ph2P)2Pt(C„CFc)] entity thus ap-
pears to be slightly less electron donating than [Pt(PPh3)2(C6H4-
(-4-COMe))], while the (Ph3P)Au and ((FcC„C)Ph2P)Au entities
are even weaker donors. This also matches the trends in the oxida-
tion potentials of the metal bonded FcC„C subunit (Table 4).
3. Conclusion
Fig. 13. Spectroscopic changes upon stepwise oxidation of
5
(1,2-C2H4Cl2/
Different synthesis methods for the preparation of ferrocene-
ethynyl phosphine and phosphine oxide transition metal complexes
of structural type (FcC„C)3P@O, [((FcC„C)nPh3ꢀnP)AuCl] (n = 1, 2),
[((FcC„C)Ph2P)AuC„CMc], [((FcC„C)nPh3ꢀnP)AuC „CMc] (n = 1,
2), cis-[((FcC„C)nPh3ꢀnP)2PtCl2] and trans-[((FcC„C)Ph2P)2Pt(C„
[nBu4N]PF6) in an OTTLE cell. (a) Spectroscopic changes upon the first oxidation
to [5]Å+, (b) the second oxidation to [5]2+and (c) the third oxidation to [5]4+
.
dioxidized [5]2+ and from the value of the comproportionation con-
stant Kcomp the spectrum of [5]Å+ can be calculated. It is given as
Fig. 14. The low energy portion of the spectrum is adequately sim-
ulated by a single band peaking at 1013 nm. Given the general
appearance of low energy absorptions in every complex with a me-
tal-bonded oxidized C„CFc+ moiety, we assign this band to the
Pt ? C„CFc+ charge transfer transition. The absence of any dis-
cernible FcC„C ? FcC„C+ intervalence charge transfer band char-
acterizes [5]Å+ as a localized mixed-valent system [45].
CFc)2] (Mc@Fc, Rc; Fc = (
g g g
5-C5H5)( 5-C5H4)Fe; Rc = ( 5-C5H5)
(g
5-C5H4)Ru) are reported. In these species ferrocene and/or ruthe-
nocene sandwich units are interconnected by ethynyl phosphine
and metal-ethynyl bridging units. Electrochemical studies show
chemically reversible oxidations of the metal and phosphine-
bonded FcC„C moieties. The half-wave potentials of these pro-
cesses respond to the electron density at the heterometal moiety.
Upon oxidation of the
r-bonded McC„C entities low energy
absorption bands appear in the near infrared that are likely associ-
ated with the transfer of charge from the heterometal atom M to
C„CMc+. These bands show the expected blue shift as M becomes
less electron donating, i.e., as the redox asymmetry between the
M and FcC„C redox sites increases. Our results also argue against
any ‘‘electronic coupling” between the oxidized Fc+ and the reduced
Fc site across the –C„C–Pt(PPh2(C„CFc))2–C„C– linker in mono-
oxidized [5]Å+ despite the 95 mV splitting of redox potentials.
In analogy to complex 9a and in further keeping with the
Pt ? C„CFc+ assignment, the 1013 nm band of [5]Å+ undergoes a
stepwise blue shift with a concomitant increase in overall intensity
as further ferrocene tags are oxidized ([5]Å+ ? [5]2+, [5]2+ ? [5]4+
,
Fig. 13b and c). For both, [5]2+ and [5]4+, the band envelope is nota-
bly asymmetric and requires the inclusion of two separate absorp-
tions in the deconvolution procedure (see Table 5).

A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
663
a
JHH = 1.9 Hz, Hb/C5H4), 4.21 (pt, JHH = 1.7 Hz, H /C5H4), 7.35–7.53
4. Experimental
(m, 12H, C6H5), 7.81–7.97 (m, 8H, C6H5). 13C{1H} NMR (d, CDCl3):
61.3 (Ci/C5H4), 70.0 (Cb/C5H4), 70.2 (C5H5), 72.8 (C /C5H4), 111.0
a
4.1. General data
(C/C„C), 128.3 (d, JCP = 6.4 Hz Cm/C6H5), 129.3 (d, JCP = 77.4 Hz,
Ci/C6H5), 131.3 (Cp/C6H5), 133.8 (pt, JCP = 6.1 Hz, Co/C6H5). 31P{1H}
All reactions were carried out under an atmosphere of nitrogen
using standard Schlenk techniques. Tetrahydrofuran, diethyl ether,
n-hexane and n-pentane were purified by distillation from sodium/
benzophenone ketyl; dichloromethane was purified by distillation
from calcium hydride. Celite (purified and annealed, Erg. B.6, Rie-
del de Haen) was used for filtrations.
NMR (d, CDCl3): -12.1 (J
= 3760 Hz).
31P195Pt
4.5. Synthesis of cis-[((FcC„C)2PhP)2PtCl2] (3b)
Complex 3b was synthesized on a similar manner as discussed
for 3a: 70 mg (0.15 mmol) of [(PhC„N)2PtCl2] (2), 156 mg
(0.30 mmol) of (FcC„C)2PhP (1b). After appropriate work-up, com-
plex 3b was obtained as an orange solid. Yield: 180 mg (0.14 mmol,
92% based on 2).
4.2. Instruments
Infrared spectra were recorded with a Perkin–Elmer FT-IR spec-
trometer Spectrum 1000. 1H NMR spectra were recorded with a
Bruker Avance 250 spectrometer operating at 250.130 MHz in
the Fourier transform mode; 13C{1H} NMR spectra were recorded
at 62.860 MHz. Chemical shifts are reported in d units (parts per
million) downfield from tetramethylsilane with the solvent as ref-
erence signal (1H NMR: CDCl3 (99.8%), d = 7.26; (CD3)2CO (99.9%),
d = 2.05; CD3CN (99.8%), d = 1.94. 13C{1H} NMR: CDCl3 (99.8%),
d = 77.16; (CD3)2CO (99.9%), d = 29.84, 206.26). The abbreviation
pt in the 1H NMR spectra corresponds to pseudo-triplet. Cyclic vol-
tammograms were recorded in a dried cell purged with purified ar-
gon. Platinum wires served as working electrode and counter
electrode. A saturated calomel electrode in a separated compart-
ment or a silver wire served as (pseudo)reference electrode. In
the latter case, potential calibration was done by addition of ferro-
cene to the analyte solution. All electrode potentials are converted
using the redox potential of the ferrocene–ferrocenium couple
Anal. Calc. for C60H48Cl2Fe4P2Pt (1318.97): C, 54.59; H, 3.67.
Found: C, 54.23; H, 3.65%. M.p.: 146 °C (decomp.). IR (KBr, cmꢀ1):
2158 (s, m
C„C). 1H NMR (d, CDCl3): 4.20 (s, 20H, C5H5), 4.25 (pt,
JHH = 1.9 Hz, 8H, Hb/C5H4), 4.41 (pdq, JHH = 11.6 Hz, JHH = 1.4 Hz,
a
JHH = 1.9 Hz, 8H, H /C5H4), 7.45–7.59 (m, 6H, C6H5), 8.18–8.32 (m,
4H, C6H5). 13C{1H} NMR (d, CDCl3): 61.4 (Ci/C5H4), 70.1 (Cb/C5H4),
70.5 (C5H5), 72.5 (C /C5H4), 128.7 (d, JCP = 7.1 Hz, Cm/C6H5), 128.9
a
(Ci/C6H5), 131.8 (Cp/C6H5), 133.4 (pt, JCP = 7.4 Hz, Co/C6H5). 31P{1H}
NMR (d, CDCl3): ꢀ43.2 (J
= 3886 Hz).
31P195Pt
4.6. Synthesis of cis-[((FcC„C)3P)2PtCl2] (3c)
Complex 3c was synthesized in a similar manner as described
for 3a: 165 mg (0.35 mmol) of [(PhC„N)2PtCl2] (2), 460 mg
(0.70 mmol) of (FcC„C)3P (1c). After appropriate work-up, com-
plex 3c was isolated as an orange solid. Yield: 515 mg (0.33 mmol,
93% based on 2).
[FcH/FcH+] (FcH = ( 5-C5H5)2Fe, E0 = 0.00 V, [20,21] as reference.
g
Electrolyte solutions were prepared from tetrahydrofuran (for 5)
or dichloromethane (for 9a and 9b) and [nBu4N]PF6 (Fluka, dried
in oil-pump vacuum). The respective organometallic complexes
were added at c = 1.0 mM. Cyclic voltammograms were recorded
using a Voltalab 3.1 potentiostat (Radiometer) equipped with a
digital electrochemical analyzer DEA 101 and an electrochemical
interface IMT 102 or a BAS CV 50 instrument. Spectro-electrochem-
istry was performed in a home-built optically transparent thin-
layer electrolysis (OTTLE) cell following the design of Hartl and
coworkers [46]. Melting points were determined using analytically
pure samples, sealed off in nitrogen purged capillaries on a Gal-
lenkamp MFB 595 010 M melting point apparatus. Microanalyses
were performed by the Institute of Organic Chemistry, Chemnitz,
University of Technology and by the Institute of Organic Chemistry,
University of Heidelberg.
Anal. Calc. for C72H54Cl2Fe6P2Pt (1580.88): C, 54.65; H, 3.44.
Found: C, 54.41; H, 3.34%. M.p.: 135 °C (decomp.). IR (KBr, cmꢀ1):
2156 (s,
m
C„C). 1H NMR (d, CDCl3): 4.29 (pt, JHH = 1.9 Hz, 12H, Hb/
a
C5H4), 4.30 (s, 30H, C5H5), 4.61 (pt, JHH = 1.9 Hz, 12 H, H /C5H4).
13C{1H} NMR (d, CDCl3): 61.2 (Ci/C5H4), 70.3 (Cb/C5H4), 70.8 (C /
a
C5H4), 72.7 (C5H5). 31P{1H} NMR (d, CDCl3): ꢀ77.1
(J31
= 4029 Hz).
P195Pt
4.7. Synthesis of trans-[((FcC„C)Ph2P)2Pt(C„CFc)2] (5)
To 170 mg (0.16 mmol) of [(FcC„CPh2P)2PtCl2] (3a) and 67 mg
(0.32 mmol) of ethynylferrocene (4a) dissolved in 40 mL of diiso-
propylamine was added 1 mg of [CuI]. After 1 day of stirring, all
volatiles were removed in oil-pump vacuum and the orange residue
was chromatographed on alumina with dichloromethane/n-hex-
ane (1:1, vs/vs) as eluent. Complex 6 was isolated as an orange so-
lid. Yield: 170 mg (0.12 mmol, 75% based on 3a).
4.3. Reagents
FcC„CH [47a], RcC„CH [47b], [(PhC„N)2PtCl2] [48],
[(tht)AuCl] [49], and (FcC„C)nPh3ꢀnP (n = 1, 2, 3) [5b] were pre-
pared according to published procedures. All other chemicals were
purchased by commercial suppliers and were used without further
purification.
Anal. Calc. for C72H56Fe4P2Pt ꢄ 1/3CH2Cl2 (1427.10): C, 60.76; H,
3.99. Found: C, 60.79; H, 4.15%. M.p.: 198 °C (decomp.). IR (KBr,
cmꢀ1): 2180 (m,
mPtC„C), 2162 (m, m
PC„C). 1H NMR (d, CDCl3):
3.81 (pt, JHH = 1.7 Hz, 4H, HbC5H4/FcC„CPt), 3.84 (s, 10H, C5H5/
a
FcC„CPt), 3.86 (pt, JHH = 1.7 Hz, 4H, H C5H4/FcC„CPt), 4.19 (s,
10H, C5H5/FcC„CP), 4.23 (pt, JHH = 1.9 Hz, 4H, Hb/C5H4/FcC„CP),
a
4.4. Synthesis of cis-[(FcC„C)Ph2P)2PtCl2] (3a)
4.55 (pt, JHH = 1.9 Hz, 4H, H /C5H4/FcC„CP), 5.29 (s, CH2Cl2),
7.44–7.50 (m, 12H, C6H5), 8.08–8.19 (m, 8H, C6H5). 31P{1H} NMR
One hundred milligrams (0.21 mmol) of [(PhC„N)2PtCl2] (2)
and 167 mg (0.42 mmol) of (FcC„C)Ph2P (1a) were dissolved in
40 mL of dichloromethane and were stirred for 1 h at 25 °C. After-
ward the reaction solution was reduced in volume under reduced
pressure and the orange title compound was precipitated by addi-
tion of petroleum ether. Yield: 190 mg (0.18 mmol, 85% based 2).
Anal. Calc. for C48H38Cl2Fe2P2Pt (1053.02): C, 54.70; H, 3.64.
Found: C, 54.23; H, 3.65%. M.p.: 216 °C (decomp.). IR (KBr, cmꢀ1):
(d, CDCl3): ꢀ7.3 (J
= 2765).
31P195Pt
4.8. Synthesis of (FcC„C)3P=O (6)
Through a solution of 40 mL tetrahydrofuran containing 100 mg
(0.15 mmol) of (FcC„C)3P (1c) was bubbled air for 1 h at 40 °C.
After evaporation of the solvent in oil-pump vacuum, the title
compound was obtained as a red–orange solid. Yield: 101 mg
(0.15 mmol, 99% based on 1c).
2159 (s, m
C„C). 1H NMR (d, CDCl3): 4.04 (s, 10H, C5H5), 4.16 (pt,

664
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
Anal. Calc. for C36H27Fe3PO (673.99): C, 64.10; H, 4.04. Found: C,
furan over a period of 1 h at 0 °C. After appropriate work-up
(see 8a), the title compound was column chromatographed on
silica gel using diethyl ether as eluent. Complex 8b could be ob-
tained as an orange solid. Yield: 486 mg (0.64 mmol, 86% based
on 7).
64.14; H, 4.23%. M.p.: 178 °C (decomp.). IR (KBr, cmꢀ1): 2151 (s,
m
C„C), 1254 (w,
m
P@O). 1H NMR (d, CDCl3): 4.32 (s, 15H, C5H5),
a
4.34 (pt, JHH = 1.7 Hz, 6H, Hb/C5H4), 4.65 (pt, JHH = 1.7 Hz, 6H, H /
C5H4). 13C{1H} NMR (d, CDCl3): 62.3 (Ci/C5H4), 70.5 (Cb/C5H4),
70.7 (C5H5), 72.8 (C /C5H4), 109.7 (C„C). 31P{1H} NMR (d, CDCl3):
Anal. Calc. for C30H23AuClFe2P (757.96): C, 47.50; H, 3.06.
a
ꢀ66.8.
Found: C, 47.80; H, 3.21%. M.p.: 93 °C. IR (KBr, cmꢀ1): 2154 (s,
m
C„C). 1H NMR (d, CDCl3): 4.26 (s, 10H, C5H5), 4.33 (pt, JHH = 1.9 Hz,
a
4.9. Synthesis of [(FcC„C)Ph2PAuCl] (8a)
4H, Hb/C5H4), 4.59 (pt, JHH = 1.6 Hz, 4H, H /C5H4), 7.50–7.58 (m, 3H,
C6H5), 7.91–8.03 (m, 2H, C6H5). 13C{1H} NMR (d, CDCl3): 61.2 (d,
JCP = 2.9 Hz, Ci/C5H4), 70.4 (Cb/C5H4), 70.5 (C5H5), 72.7 (d,
To
a tetrahydrofuran solution (30 mL) containing 240 mg
a
(0.75 mmol) of [(tht)AuCl] (7) was added dropwise a solution with
283 mg (1.132 mmol) of (FcC„C)Ph2P (1a) in 30 mL of tetrahydro-
furan over a period of 1 h at 0 °C. After 1 h of stirring at 25 °C, all
volatiles were removed in oil-pump vacuum. The title compound
was chromatographed on silica gel with diethyl ether as eluent.
Compound 8a was isolated as an orange solid. Yield: 350 mg
(0.73 mmol, 97% based on 7).
JCP = 4.8 Hz, C /C5H4), 75.4 (C„C), 109.2 (d, JCP = 24.3 Hz, C„C),
129.4 (d, JCP = 12.8 Hz, Cm/C6H5), 129.5 (Ci/C6H5), 131.8 (Cp/C6H5),
132.4 (d, JCP = 18.3 Hz, Co/C6H5). 31P{1H} NMR (d, CDCl3): ꢀ37.5.
4.11. Synthesis of [((FcC„C)Ph2P)AuC„CFc] (9a)
Anal. Calc. for C24 H19AuClFeP (625.99): C, 46.01; H, 3.06. Found:
To
a diethylamine solution (50 mL) containing 150 mg
C, 45.97; H, 3.17%. M.p.: 181 °C (decomp.). IR (KBr, cmꢀ1): 2158 (s,
m
(0.24 mmol) of [((FcC„C)Ph2P)AuCl] (8a) and 60 mg (0.29 mmol)
of ethynylferrocene was added 1 mg of [CuI]. After 2 h stirring at
25 °C all volatiles were removed in oil-pump vacuum and 9a was
purified by chromatography on silica gel with a hexane/diethyl
ether mixture (1:4, vs/vs) as eluent. Yield: 160 mg (0.20 mmol,
84% based on 8a).
C„C). 1H NMR (d, CDCl3): 4.25 (s, 5H, C5H5), 4.37 (pt, JHH = 1.9 Hz,
a
2H, Hb/C5H4), 4.63 (pt, JHH = 1.9 Hz, 2H, H /C5H4), 7.44–7.58 (m, 6H,
C6H5), 7.75–7.88 (m, 4H, C6H5). 13C{1H} NMR (d, CDCl3): 60.6 (d,
JCP = 3.8 Hz, Ci/C5H4), 70.6 (C5H5), 70.6 (Cb/C5H4), 72.8 (d,
a
JCP = 1.4 Hz, C /C5H4), 112.5 (d, JCP = 22.8 Hz, C„C), 129.4 (d,
JCP = 13.0 Hz, Cm/C6H5), 129.8 (d, JCP = 71.0 Hz, Ci/C6H5), 132.2 (d,
JCP = 2.9 Hz, Cp/C6H5), 133.0 (d, JCP = 15.8 Hz, Co/C6H5). 31P{1H}
NMR (d, CDCl3): 1.9.
Anal. Calc. for C36H28AuFe2P (800.03): C, 54.00; H, 3.53. Found:
C, 54.05; H, 3.85%. M.p.: 89 °C. IR (KBr, cmꢀ1): 2157 (s, C„C). 1H
m
NMR (d, CDCl3): 4.13 (pt, JHH = 1.9 Hz, 2H, Hb/AuC„CFc), 4.22 (s,
5H, C5H5/AuC„CFc), 4.25 (s, 5H, C5H5/PC„CFc), 4.35 (pt,
JHH = 1.9 Hz, 2H, Hb/PC„CFc), 4.46 (pt, JHH = 1.9 Hz, 2H, H /
a
4.10. Synthesis of [((FcC„C)2PhP)AuCl] (8b)
a
AuC„CFc), 4.61 (pt, JHH = 1.9 Hz, 2H, H /PC„CFc), 7.42–7.54 (m,
6H, C6H5), 7.77–7.90 (m, 4H, C6H5). 13C{1H} NMR (d, CDCl3): 61.1
(d, JCP = 3.0 Hz, Ci/C5H4/PC„CFc), 67.4 (Ci/C5H4/AuC„CFc), 68.0
(C5H4/AuC„CFc), 70.2 (C5H5/AuC„CFc), 70.4 (C5H4/AuC„CFc),
To
a tetrahydrofuran solution (30 mL) containing 526 mg
(1.00 mmol) of (FcC„C)2PhP (1b) in 30 mL were added 240 mg
(0.75 mmol) of [(tht)AuCl] (7) dissolved in 30 mL of tetrahydro-
Table 6
Crystal and Intensity Collection Data for 3c, 5 and 6.
3c
5
6
Formula weight
Chemical formula
Crystal system
Space group
a (Å)
1709.57
1486.52
674.10
C72H54Cl2Fe6P2Pt 1.5 CH2Cl2
Triclinic
C72H56Fe4P2Pt CH2Cl2
Triclinic
C36H27Fe3OP
Monoclinic
P21/c
12.5325(7)
11.9733(8)
18.7893(15)
ꢀ
ꢀ
P1
P1
12.9786(10)
15.7926(11)
16.5193(15)
96.071(7)
106.794(7)
96.893(6)
3182.7(4)
1.784
1694
8.1907(6)
b (Å)
c (Å)
11.9938(7)
16.4187(10)
72.625(5)
79.284(6)
74.838(6)
1475.54(16)
1.673
a
(°)
b (°)
103.321(6)
c
(°)
V (Å3)
2743.6(3)
1.632
1376
qcalc (g cmꢀ3
F(000)
)
742
Crystal dimensions (mm)
Z
0.05 ꢄ 0.02 ꢄ 0.02
0.4 ꢄ 0.1 ꢄ 0.02
0.3 ꢄ 0.1 ꢄ 0.1
2
1
4
Maximum and minimum Transmission
1.00000, 0.86690
3.823
2.88–26.07
ꢀ16 ꢅ h ꢅ 16, ꢀ19 ꢅ k ꢅ 19,
ꢀ20 ꢅ l ꢅ 20
31935
1.00000, 0.84829
3.511
3.28–26.06
ꢀ10 ꢅ h ꢅ 10, ꢀ14 ꢅ k ꢅ 14,
ꢀ20 ꢅ l ꢅ 20
14372
1.01231, 0.98667
1.654
2.99–26.00
ꢀ15 ꢅ h ꢅ 15, ꢀ14 ꢅ k ꢅ 14,
ꢀ23 ꢅ l ꢅ 23
26684
Absorption coefficient (k, mmꢀ1
Scan range (°)
)
Index ranges
Total reflections
Unique reflections
Rint
12570
0.0438
5783
0.0388
5393
0.0229
Data/restraints/parameters
12570/0/793
0.933
0.0310, 0.0507
0.0551, 0.0573
1.802, ꢀ1.298
5783/12/397
0.977
0.0288, 0.0528
0.0416, 0.0580
1.295, ꢀ0.848
5393/0/370
1.032
0.0221, 0.0585
0.0282, 0.0602
0.357, ꢀ0.499
Goodness-of-fit on F2
a
R1a, wR2 [I 2
r
(I)]
a
R1a, wR2 (all data)
Largest difference peak and hole (e Åꢀ3
)
(w(F2o ꢀ F2c )2)/
R
(wF4o)]1/2. S = [
R
w(F2o ꢀ F2c )2]/(n ꢀ p)1/2. n = number of reflections, p = parameters used.
a
R1 = [
R
(||Fo| ꢀ |Fc|)/
R
|Fo|); wR2 = [
R

A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
665
Table 7
Crystal and intensity collection data for 8a, 9a, and 9b.
8a
9a
9b
Formula weight
Chemical formula
Crystal system
Space group
a (Å)
626.63
800.22
C36H28AuFe2P
Monoclinic
P21/c
15.3726(17)
7.5512(5)
24.927(3)
106.505(10)
905.12
C24H19AuClFeP
Monoclinic
P21/n
9.9198(7)
19.1756(15)
12.0771(9)
113.071(7)
2113.5(3)
1.969
C36H28AuFePRu 0.5 CHCl3
Monoclinic
P21/a
13.7289(10)
18.3090(13)
14.4577(8)
114.223(6)
3314.2(4)
1.814
b (Å)
c (Å)
b (°)
V (Å3)
2774.3(5)
1.916
1560
qcalc (g cmꢀ3
F(000)
)
1200
1748
Crystal dimensions (mm)
Z
0.5 ꢄ 0.2 ꢄ 0.1
0.5 ꢄ 0.2 ꢄ 0.1
0.3 ꢄ 0.2 ꢄ 0.05
4
4
4
Maximum and minimum Transmission
1.47670, 0.34621
7.829
3.08–26.08
ꢀ12 ꢅ h ꢅ 12, ꢀ23 ꢅ k ꢅ 23,
ꢀ14 ꢅ l ꢅ 14
20397
1.19314, 0.68665
6.390
4.90–25.50
ꢀ18 ꢅ h ꢅ 18, ꢀ8 ꢅ k ꢅ 9, ꢀ30 ꢅ l ꢅ 30
1.00000, 0.46972
5.491
2.97–26.09
ꢀ16 ꢅ h ꢅ 16, ꢀ22 ꢅ k ꢅ 22,
ꢀ17 ꢅ l ꢅ 17
32220
Absorption coefficient (k, mmꢀ1
Scan range (°)
)
Index ranges
Total reflections
Unique reflections
Rint
17054
5026
0.0276
4171
0.0286
6536
0.0349
Data/restraints/parameters
4171/0/253
1.055
0.0165, 0.0384
0.0216, 0.0393
0.848, ꢀ0.727
5026/15/361
1.045
0.0258, 0.0598
0.0299, 0.0610
3.073, ꢀ1.151
6536/41/394
1.102
0.0384, 0.1090
0.0548, 0.1152
3.845, ꢀ1.583
Goodness-of-fit on F2
a
R1a, wR2 [I 2
r
(I)]
a
R1a, wR2 (all data)
Largest difference peak and hole (e Åꢀ3
)
(w(F2o ꢀ F2c )2)/
R
(wF4o)]1/2. S = [
R
w(F2o ꢀ F2c )2]/(n ꢀ p)1/2. n = number of reflections, p = parameters used.
a
R1 = [R
(||Fo| ꢀ |Fc|)/
R
|Fo|); wR2 = [
R
70.5 (C5H5/PC„CFc), 72.0 (CbC5H4/PC„CFc), 72.7 (d, JCP = 1.0 Hz,
Supplementary material
a
C /C5H4/PC„CFc), 129.3 (d, JCP = 12.5 Hz, Cm/C6H5), 130.8 (d,
JCP = 63.3 Hz, Ci/C6H5), 131.8 (d, JCP = 2.4 Hz, Cp/C6H5), 133.2 (d,
JCP = 15.8 Hz, Co/C6H5). 31P{1H} NMR (d, CDCl3): 15.1.
CCDC 697272, 697273, 697271, 697269, 697268 and 697270
contain the supplementary crystallographic data for 3c, 5, 6, 8a,
9a and 9b. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via http://www.ccdc.ca-
m.ac.uk/data_request/cif.
4.12. Synthesis of [((FcC„C)Ph2P)AuC„CRc] (9b)
Complex 9b was synthesized in a similar manner as discussed
for 9a: 150 mg (0.24 mmol) of [((FcC„C)Ph2P)AuCl] (8) were re-
acted with 80 mg (0.31 mmol) of ethynyl ruthenocene at 50 °C.
After appropriate work-up, compound 9b was isolated as an or-
ange–yellow solid. Yield: 180 mg (0.21 mmol, 89%).
Acknowledgement
We are grateful to the Deutsche Forschungsgemeinschaft and
the Fonds der Chemischen Industrie for financial support. Cathari-
na Meier is acknowledged for fruitful discussions.
Anal. Calc. for C36H28AuFePRu ꢄ CH2Cl2 (930.93): C, 47.74; H,
3.25. Found: C, 48.18; H, 3.25%. M.p.: 95 °C. IR (KBr, cmꢀ1): 2167
(s,
JHH = 1.7 Hz, 2H, Hb/Fc), 4.49 (pt, JHH = 1.7 Hz, 2H, Hb/Rc), 4.59–
m
C„C). 1H NMR (d, CDCl3): 4.24 (s, 5H, C5H5/Fc), 4.35 (pt,
References
a
a
[1] (a) M.I. Bruce, P.A. Humphrey, M. Jevric, G.J. Perkins, B.W. Skelton, A.H. White
J. Organomet. Chem. 692 (2007) 1748;
4.61 (m, 2H, H /Fc; 5H, C5H5/Rc), 4.88 (pt, JHH = 1.7 Hz, 2H, H /
Rc), 5.29 (CH2Cl2) 7.41–7.56 (m, 6H, C6H5), 7.76–7.88 (m, 4H,
C6H5). 13C{1H} NMR (d, CDCl3): 70.0 (C5H4/Rc), 70.4 (CbC5H4/Fc),
(b) J. Durand, S. Gladiali, G. Erre, E. Zangrando, B. Milani, Organometallics 26
(2007) 810;
(c) R.C.J. Atkinson, K. Gerry, V.C. Gibson, N.J. Long, E.L. Marshall, L.J. West,
Organometallics 26 (2007) 316;
a
70.5 (C5H5/Fc), 71.9 (C5H5/Rc), 72.7 (d, JCP = 1.0 Hz, C /C5H4/Fc),
74.4 (C5H4/Rc), 129.3 (d, JCP = 12.5 Hz, Cm/C6H5), 130.8 (d,
JCP = 64.3 Hz, Ci/C6H5), 131.8 (Cp/C6H5), 133.2 (d, JCP = 15.4 Hz, Co/
C6H5). 31P{1H} NMR (d, CDCl3): 14.9.
(d) P. Debroy, S. Roy, Coord. Chem. Rev. 251 (2007) 203;
(e) T.Y. Dong, M. Lin, M.Y.N. Chiang, J.Y. Wu, Organometallics 23 (2004) 3921;
(f) T.Y. Dong, K. Chen, M.C. Lin, L. Lee, Organometallics 24 (2005) 4198;
(g) N.J. Long, Angew. Chem., Int. Ed. 34 (1995) 21;
(h) Special issue, ‘‘50th Anniversary of the Discovery of Ferrocene”, J.
Organomet. Chem. 637–639 (2001), (R.D. Adams, Ed.), and references therein.
[2] (a) C.P. Berlinguette, K.R. Dumbar, Chem. Commun. (2005) 2451;
(b) S. Santi, L. Orian, A. Donoli, C. Durante, A. Bisello, P. Ganis, A. Ceccon,
Organometallics 26 (2007) 5867;
5. Crystal structure determinations
Crystal and intensity collection data for 3c, 5, 6, 8a, 9a, and 9b
are summarized in Table 6 (3c, 4, and 6) and Table 7 (8a, 9a, and
9b). All data were collected on a Oxford Gemini S diffractometer
(c) K. Heinze, S. Reinhardt, Organometallics 26 (2007) 5406;
(d) S. Rabaça, I.C. Santos, M.T. Duarte, V. Gama, Inorg. Chim. Acta 360 (2007)
3855.
with graphite monochromatized Mo K
at 100 K (4, 6, 8a, 9a, and 9b) and Cu K
110 K (3c) using oil-coated shock-cooled crystals [50]. The struc-
tures were solved by direct methods using SHELXS-97 [51] and SIR
a
radiation (k = 0.71073 Å)
[3] (a) F. Barrière, R.U. Kirss, W.E. Geiger, Organometallics 24 (2005) 48;
(b) A. Shafir, M.P. Power, G.D. Whitener, J. Arnold, Organometallics 19 (2000)
3978;
a
radiation (k = 1.54 Å) at
(c) A. Mendiratta, S. Barlow, M.W. Day, S.R. Marder, Organometallics 18 (1999)
454.
-
[4] (a) M.I. Bruce, Coord. Chem. Rev. 248 (2004) 1603;
(b) S. Szafert, J.A. Gladysz, Chem. Rev. 106 (2006) PR1;
(c) C. Lapinte, J. Organomet. Chem. 693 (2008) 793;
(d) H. Lang, D.S.A. George, G. Rheinwald, Coord. Chem. Rev. 206–207 (2000)
101;
92 (3c) [53] and refined by full-matrix least-square procedures
on F2 using SHELXL-97. [52] All non-hydrogen atoms were refined
anisotropically and a riding model was employed in the refinement
of the hydrogen atom positions.

666
A. Jakob et al. / Journal of Organometallic Chemistry 694 (2009) 655–666
(e) P.J. Low, Annu. Rep. Prog. Chem. Sect. A 102 (2006) 379;
[18] (a) K. Rößler, T. Rüffer, B. Walfort, R. Packheiser, R. Holze, M. Zharnikov, H.
Lang, J. Organomet. Chem. 692 (2007) 1530;
(b) T.J. Burchell, M.C. Jennings, R.J. Puddephatt, Inorg. Chim. Acta 359 (2006)
2812.
[19] R. Packheiser, A. Jakob, P. Ecorchard, B. Walfort, H. Lang, Organometallics 27
(2008) 1214.
[20] G. Gritzner, J. Kuta, Pure Appl. Chem. 56 (1984) 461.
[21] H. Strehlow, W. Knoche, H. Schneider, Ber. Bunsen. Phys. Chem. 77 (1973) 760.
[22] (a) T. Kuwana, D.E. Bublitz, G. Hoh, J. Am. Chem. Soc. 82 (1960) 5811;
(b) S.P. Gubin, S.A. Smirnova, L.I. Denisovich, A.A. Lubovich, J. Organomet.
Chem. 30 (1971) 243;
(f) K. Venkatesan, O. Blacque, H. Berke, Dalton Trans. (2007) 1091;
(g) H. Lang, R. Packheiser, Collect. Czech. Chem. Commun. 72 (2007) 435;
(h) H. Lang, A. Jakob, Organometallic Chemistry Research Perspectives, in:
Richard P. Irwin (Ed.), Nova Science Publishers Inc., 2007, p. 99;
(i) N.J. Long, C.K. Williams, Angew. Chem., Int. Ed. 42 (2003) 2586;
(j) K.-L. Cheung, S.-K. Yip, V.W.-W. Yam, J. Organomet. Chem. 689 (2004) 4451;
(k) K.-C. Cheung, W.-L. Wong, D.-L. Ma, T.-S. Lai, K.-Y. Wong, Coord. Chem. Rev.
251 (2007) 2367;
(l) T.-Y. Dong, M.-C. Lin, M. Y.-N. Chiang, J.-Y. Wu, Organometallics 23 (2004)
3921;
(m) M.P. Cifuentes, M.G. Humphrey, J. Organomet. Chem. 689 (2004) 3968;
(n) B. Bildstein, Coord. Chem. Rev. 206–207 (2000) 369;
(o) R. Packheiser, P. Ecorchard, T. Rüffer, H. Lang, Organometallics 27 (2008)
3534;
(p) T. Baumgartner, R. Réau, Chem. Rev. 106 (2006) 4681;
(q) R. Malacea, E. Manoury, L. Routaboul, J.-C. Daran, R. Poli, J.P. Dunne, A.C.
Withwood, C. Godard, S.B. Duckett, Eur. J. Inorg. Chem. (2006) 1803;
(r) P. Teo, D.M.J. Foo, L.L. Koh, T.S.A. Hor, Dalton Trans. (2004) 3389;
(s) P.M.N. Low, A.L. Tan, T.S.A. Hor, Y.-S. Wen, L.-K. Liu, Organometallics 15
(1996) 2595;
(c) S.V. Kukharenko, V.V. Strelets, A.R. Kudinov, A.Z. Kreitlin, M.G. Peterleitner,
L.I. Denisovich, M.I. Rybinskaya, J. Organomet. Chem. 519 (1996) 1.
[23] (a) Reversible oxidation to the ruthenocenium radical cation and its
equilibrium with the dimeric [Cp2Ru–RuCp2]2+ dication has been reported in
less nucleophilic environments M.G. Hill, W.M. Lamanna, K.R. Mann, Inorg.
Chem. 30 (1991) 4690;
(b) S. Trupia, A. Nafady, W.E. Geiger, Inorg. Chem. 42 (2003) 5480.
[24] Instrumental Methods in Electrochemistry, The Southampton Electrochemical
Group, Horwood Publishing, Chichester, 2001 (Chapter 6.3.2).
[25] M. Sato, Y. Kubota, Y. Kawata, T. Fujihara, K. Unoura, A. Oyama, Chem. Eur. J. 12
(2006) 2282.
(t) W. Weigand, C. Robl, Chem. Ber. 126 (1993) 1807.
[5] (a) T. Baumgartner, M. Fiege, F. Pontzen, R. Arteaga-Müller, Organometallics
25 (2006) 5657;
[26] M. Sato, A. Iwai, M. Watanabe, Organometallics 18 (1999) 3208.
[27] M. Sato, Y. Kawata, H. Shintate, Y. Habata, S. Akabori, K. Unoura,
Organometallics 16 (1997) 1693.
[28] M. Sato, H. Shintate, Y. Kawata, M. Sekino, M. Katada, S. Kawata,
Organometallics 13 (1994) 1956.
(b) A. Jakob, B. Milde, P. Ecorchard, C. Schreiner, H. Lang, J. Organomet. Chem.
(2008). doi: 0.1016/j.jorganchem.2008.09.040;
(c) P. Low, J. Clust. Sci. 19 (2008) 5.
[6] (a) G.K. Anderson, H.C. Clark, J.A. Davis, G. Ferguson, M. Parvez, J. Crystallogr.
Spectrosc. Res. 12 (1982) 449;
[29] M.C.B. Colbert, S.L. Ingham, J. Lewis, N.J. Long, P.R. Raithby, J. Chem. Soc.,
Dalton Trans. (1994) 2215.
(b) P.M. Van Calcar, M.M. Olmstead, A.L. Balch, Chem. Commun. (1996) 2597;
(c) K. Mikami, H. Kakuno, K.A. Kawa, Angew. Chem., Int. Ed. 44 (2005) 7423.
[7] (a) A. Hengefeld, J. Kopf, D. Rehder, Organometallics 2 (1983) 114;
(b) E.C. Constable, C.E. Housecroft, B. Krattinger, M. Neuburger, M. Zehnder,
Organometallics 18 (1999) 2565;
(c) D.K. Johnson, T. Rukachaisirikul, Y. Sun, N.J. Taylor, A.J. Canty, A.J. Carty,
Inorg. Chem. 32 (1993) 5544.
[8] R. Packheiser, B. Walfort, H. Lang, Oranometallics 25 (2006) 4579.
[9] A.D. Burrows, D.M.P. Mingos, S.E. Lawrence, A.J.P. White, D.J. Williams, J. Chem.
Soc., Dalton Trans. (1997) 1295.
[30] M. Sato, E. Mogi, M. Katada, Organometallics 14 (1995) 4837.
[31] S. Back, R.A. Gossage, H. Lang, G. van Koten, Eur. J. Inorg. Chem. (2000) 1457.
[32] M. Sato, Y. Hayashi, H. Shintate, M. Katada, S. Kawata, J. Organomet. Chem. 471
(1994) 179.
[33] N.J. Long, A.J. Martin, A.J.P. White, D.J. Williams, M. Fontani, F. Laschi, P.
Zanello, J. Chem. Soc., Dalton Trans. (2000) 3387.
[34] M.C.B. Colbert, J. Lewis, N.J. Long, P.R. Raithby, A.J.P. White, D.J. Williams, J.
Chem. Soc., Dalton Trans. (1997) 99.
[35] N.D. Jones, M.O. Wolf, D.M. Giaquinta, Organometallics 16 (1997) 1352.
[36] Y. Zhu, O. Clot, M.O. Wolf, G.P.A. Yap, J. Am. Chem. Soc. 120 (1998)
1812.
[37] G. Vives, A. Carella, J.-P. Launay, G. Rapenne, Chem. Commun. (2006) 2283.
[38] (a) D. Osella, O. Gambino, C. Nervi, M. Ravera, M.V. Russo, G. Infante, Inorg.
Chim. Acta 225 (1994) 35;
(b) D. Osella, R. Gobetto, C. Nervi, M. Ravera, R. D’Amato, M.V. Russo, Inorg.
Chem. Commun. 1 (1998) 239.
[39] M. Sato, Y. Hayashi, S. Kumakura, N. Shimizu, M. Katada, S. Kawata,
Organometallics 15 (1996) 721.
[10] (a) K. Gagnon, S.M. Aly, A. Brisach-Wittmeyer, D. Bellows, J.-F. Bérubé, L.
Caron, A.S. Abd-El-Aziz, D. Fortin, P.D. Harvey, Organometallics 27 (2008)
2201;
(b) E. Robé, C. Hegedüs, J. Bakos, Y. Coppel, J.-C. Daran, M. Gouygou, Inorg.
Chim. Acta 361 (2008) 1861;
(c) T. Cardolaccia, Y. Li, K.S. Schanze, J. Am. Chem. Soc. 130 (2008) 2535;
(d) A. Sivaramakrishna, B.C.E. Makhubela, F. Zheng, H. Su, G.S. Smith, J.R. Moss,
Polyhedron 27 (2008) 44;
(e) J. Forniés, M.A. Gómez-Saso, E. Lallnde, F. Martinez, M.T. Moreno,
Organometallics 11 (1992) 2873;
[40] C.J. Adams, S.L. James, X. Liu, P.R. Raithby, L.J. Yellowlees, J. Chem. Soc., Dalton
Trans. (2000) 63.
(f) K. Sonogashira, Y. Fujikura, T. Yatake, N. Toyoshima, S. Takahashi, N.
Hagihara, J. Organomet. Chem. 145 (1978) 101;
(g) S. Takahashi, Y. Takai, H. Morimoto, K. Sonogashira, N. Hagihara, Mol.
Cryst. Liq. Cryst. 82 (1982) 139;
(h) K. Sonogashira, T. Yatake, Y. Tohda, S. Takahashi, N. Hagihara, J. Chem. Soc.,
Chem. Commun. (1977) 291;
[41] M. Ravera, R. D’Amato, A. Guerri, J. Organomet. Chem. 690 (2005) 2376.
[42] E.C. James, M.Jura;G. Kociok-Köhn, P.R. Raithby, E.L. Sharp, P.J. Wilson, Inorg.
Chem. 46 (2007) 7232.
[43] Y.-J. Chen, S.-S. Chen, S.-S. Lo, T.-H. Huang, C.-C. Wu, G.-H. Lee, S.-M. Peng, C.-Y.
Yeh, Chem. Commun. (2006) 1015.
[44] S.C. Jones, V. Coropceanu, S. Barlow, T. Kinnibrugh, T. Timofeeva, J.-L. Brédas,
S.R. Marder, J. Am. Chem. Soc. 126 (2004) 11782.
(i) K. Sonogashira, S. Takahashi, N. Hagihara, Macromolecules (1977) 879;
(j) I. Collimati, A. Furlani, J. Organomet. Chem. 17 (1969) 457;
(k) R.J. Cross, M.F. Davidson, J. Chem. Soc., Dalton Trans. (1986) 1987.
[11] R.J. Cross, I.G. Phillips, J. Chem. Soc., Dalton Trans. (1982) 2261.
[12] (a) M. Carlsson, B. Eliasson, Organometallics 25 (2006) 5500;
(b) R. D’Amato, A. Furlani, M. Colapietro, G. Portalone, M. Casalboni, M.
Falconieri, M.V. Russo, J. Organomet. Chem. 627 (2001) 13.
[13] R.F. De Ketellaere, G.P. van der Kelen, J. Mol. Struct. 23 (1974) 233.
[14] (a) G. Bandoli, G. Bortolozzo, D.A. Clemente, U. Croatto, C. Panettoni, J. Chem.
Soc. (A) Inorg. Phys. Theor. (1970) 2778;
(b) C.M. Whitaker, K.L. Kott, R.J. McMahon, J. Org. Chem. 60 (1995) 3499.
[15] J. Vicente, M.T. Chicote, M.T. Abrisqueta, J.G. Jones, Organometallics 16 (1997)
5628.
[16] H. Lang, S. Köcher, S. Back, G. Rheinwald, G. van Koten, Organometallics 20
(2001) 1968.
[45] M. B-Robin, P. Day, Adv. Inorg. Chem. Radiochem. 10 (1967) 247.
[46] M. Krejcik, M. Danek, F. Hartl, J. Electroanal. Chem. 317 (1991) 179.
[47] (a) J. Polin, H. Schottenberger, Org. Syn. 73 (1996) 262;
(b) M.O. Rausch, A. Siegel, J. Org. Chem. 34 (1969) 1974.
[48] H.H. Eysel, E. Guggolz, M. Kopp, M.L. Ziegler, Z. Anorg. Allg. Chem. 499 (1988)
81.
[49] K.C. Dash, H. Schmidbaur, Chem. Ber. 106 (1973) 1221.
[50] (a) T. Kottke, D.J. Stalke, Appl. Crystallogr. 26 (1993) 615;
(b) T. Kottke, R.J. Lagow, D.J. Stalke, Appl. Crystallogr. 29 (1996) 465;
(c) D. Stalke, Chem. Soc. Rev. 27 (1998) 171.
[51] G.M. Sheldrick, Acta Crystallogr. Sect. A 46 (1990) 467.
[52] A. Altomare, G. Cascarano, C. Giacovazzo, A. Gualardi, J. Appl. Cryst. 26 (1993)
343.
[53] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement, University
[17] N.C. Baenziger, W.E. Bennett, D.M. Soboroff, Acta Crystallogr. B 32 (1976) 962.
of Göttingen, 1997.