The first 1,1′-Digallylferrocene and a rodlike, polymeric donor-acceptor complex: Synthesis, properties, and structure of [Fe(η5-C5H4GaMe2)2] n and [Fe(η5-C5H4GaMe2)2(C 12H8N2)]n

Article abstract of DOI:10.1021/om020185d

The reaction of 1,1?-bis(trichlorostannyl)ferrocene with trimethylgallium results in the formation of Fe(C₅H₄GaMe₂)₂ (1), the first digallylferrocene. An X-ray crystal structure analysis of 1 reveals a polymeric structure. NMR data confirm a monomeric structure of [1-2 donor] in donor solvents. The reaction of 1 with phenazine results in the formation of the supramolecular polyferrocene [1·phenazine]_n. Its rodlike structure is proven by X-ray crystallography.

Full text of DOI:10.1021/om020185d

3018
Organometallics 2002, 21, 3018-3022
Th e F ir st 1,1′-Diga llylfer r ocen e a n d a Rod lik e, P olym er ic
Don or -Accep tor Com p lex: Syn th esis, P r op er ties, a n d
Str u ctu r e of [F e(η5-C5H4Ga Me2)2]n a n d
†,1
[F e(η5-C5H4Ga Me2)2(C12H8N2)]n
Alexander Althoff, Peter J utzi,* Norman Lenze, Beate Neumann,
Anja Stammler, and Hans-Georg Stammler
Fakulta¨t fu¨r Chemie, Universita¨t Bielefeld, 33615 Bielefeld, Germany
Received March 5, 2002
The reaction of 1,1′-bis(trichlorostannyl)ferrocene with trimethylgallium results in the
formation of Fe(C5H4GaMe2)2 (1), the first digallylferrocene. An X-ray crystal structure
analysis of 1 reveals a polymeric structure. NMR data confirm a monomeric structure of
[1‚2 donor] in donor solvents. The reaction of 1 with phenazine results in the formation of
the supramolecular polyferrocene [1‚phenazine]n. Its rodlike structure is proven by X-ray
crystallography.
In tr od u ction
Although ferrocene chemistry is by now a well-
developed area, the literature reveals only a few fer-
rocene derivatives bearing group 13 element alkyl
substituents. Among these are two ferrocenylboranes,
(η5-C5H5)Fe(η5-C5H4BMe2) and Fe(η5-C5H4BMe2)2,1,2 and
a few ferrocenylalanes, [(η5-C5H5)Fe(η5-C5H3Al2Me3Cl)]2
and (η5-C5H5)Fe(η5-C5H4Al2R4Cl) (R ) Me, Et).3 Only
two ferrocenylgallanes have been reported, [(η5-C5H5)-
Fe(η5-C5H4GaMe2)]2 and {(η5-C5H5)Fe[η5-C5H3(GaMe2)-
(CH2NMe2)]}2;4 these compounds were shown by X-ray
crystallography to consist of molecular species in the
solid state. Until recently ferrocene derivates with ElR2
groups (El ) Al, Ga, In, Tl) in 1,1′-position were
unknown. In a preliminary report, we have described
1,1′-bis(dimethylgallyl)ferrocene 1 as a starting material
for the synthesis of the novel gallaferrocenophanes [2‚
2Py] and [3‚2Py] (eq 1).5 Complex [2‚2Py] is the first
[1.1]ferrocenophane with group 13 elements in the
bridging positions. [3‚2Py] is the first member of a new
class of compounds with a “carousel structure”. Note
that since we published the synthesis of [2‚2Py], the
alkylgallium-bridged [1.1]ferrocenophane [{Fe(C5H4)2}2-
{GaCH(SiMe3)2}2] has also been reported.6
The favorable electrochemical properties make fer-
rocene molecules especially promising candidates for the
incorporation into polymer chains. Such materials have
been shown to possess interesting electrical, magnetic,
and optical properties as a result of electron delocaliza-
tion.7 So far, four major pathways to poly(ferrocenes)
have been developed: polycondensation reactions using
difunctional ferrocenes,7 the polymerization of ferrocene
derivatives bearing polymerizable substituents,7 ther-
mal8 or catalytic9 ring-opening polymerization of strained
[1]- and [2]-ferrocenophanes, and coordination polymer
synthesis.10 The last method is based on the formation
of donor-acceptor bonds between difunctional nitrogen
† Dedicated to Professor Gottfried Huttner on the occasion of his
65th birthday.
(1) Herein we use the terms “gallyl” and “galla” (analogous to
corresponding terms, e.g., for the element tin “stannyl”, “stanna”),
which are not recommended in the IUPAC rules for the nomenclature
of organometallic compounds.
(2) (a) Renk, T.; Ruf, W.; Siebert, W. J . Organomet. Chem. 1976,
120, 1. (b) Renk, T.; Ruf, W.; Siebert, W. Z. Naturforsch. 1976, 31b,
1028.
(3) (a) Atwood, J . L.; Bailey, B. L.; Kindberg, B. L.; Cook, W. J . Aust.
J . Chem. 1973, 26, 2297. (b) Atwood, J . L.; Shoemaker; A. L. J . Chem.
Soc., Chem. Commun. 1976, 536. (c) Rogers, R. D.; Cook, W. J .; Atwood,
J . L. Inorg. Chem. 1979, 18, 279. (d) Robinson, G. H.; Bott, S. G.;
Atwood, J . L. J . Coord. Chem. 1987, 16, 219.
(6) Uhl, W.; Hahn, I.; J antschak, A.; Spies, T. J . Organomet. Chem.
2001, 637-639, 300.
(7) Manners, I. Angew. Chem. 1996, 108, 1712; Angew. Chem., Int.
Ed. Engl. 1996, 35, 1602.
(8) (a) Foucher, D. A.; Tang, B.-Z.; Manners, I. J . Am. Chem. Soc.
1992, 114, 6246. (b) Manners, I. Adv. Organomet. Chem. 1995, 37, 131.
(9) Sheridan, J . B.; Temple, K.; Lough, A. J .; Manners, I. J . Chem.
Soc., Dalton Trans. 1997, 711.
(4) (a) Lee, B.; Pennington, W. T.; Laske, J . A.; Robinson, G. H.
Organometallics 1990, 9, 2864. (b) Hecht, E. Z. Anorg. Allg. Chem.
2000, 626, 759.
(5) J utzi, P.; Lenze, N.; Neumann, B.; Stammler, H.-G. Angew.
Chem. 2001, 113, 1470; Angew. Chem., Int. Ed. 2001, 40, 1424.
(10) (a) Fontani, M.; Peters, F.; Scherer, W.; Wachter, W.; Wagner,
M.; Zanello, P. Eur. J . Inorg. Chem. 1998, 1453. (b) Grosche, M.;
Herdtweck, E.; Peters, F.; Wagner, M. Organometallics 1999, 18, 4669.
(c) Dinnebier, R. E.; Wagner, M.; Peters, F.; Shankland, K. David, W.
I. F. Z. Anorg. Allg. Chem. 2000, 626, 1400.
10.1021/om020185d CCC: $22.00 © 2002 American Chemical Society
Publication on Web 06/13/2002

The First 1,1′-Digallylferrocene
Organometallics, Vol. 21, No. 14, 2002 3019
bases and Fe(η5-C5H4BMe2)2 units. Among these sub-
stances, the compounds [Fe(η5-C5H4BMe2)2L]n (L ) 4,4′-
bipyridyl and pyrazine) have been structurally charac-
terized.10b,c We were interested in finding new ferrocene-
based precursors for the formation of novel coordination
polymers.
Resu lts a n d Discu ssion
Syn t h esis of 1,1′-Bis(d im et h ylga llyl)fer r ocen e
(1). Compound 1,1′-bis(dimethylgallyl)ferrocene 1 was
prepared in good yield as an orange solid by the reaction
of 1,1′-bis(trichlorostannyl)ferrocene with an excess of
trimethylgallium (eq 2).5,11 1 is sparingly soluble in
nondonor solvents and is extremely air sensitive. In the
reaction mixture, methylgallium chlorides and tetra-
methylstannane were identified by NMR spectroscopy.
F igu r e 1. Solid state structure of 1, including the unit
cell.
Two possible reaction pathways may be discussed.
The first begins with the substitution of SnCl3 by GaMe2
groups with elimination of trichloromethylstannane. In
the next steps trichloromethylstannane reacts with
excess trimethylgallium to form methylgallium chlorides
and tetramethylstannane. The other possible reaction
sequence begins with the methylation of 1,1′-bis(trichlo-
rostannyl)ferrocene to 1,1′-bis(trimethylstannyl)ferro-
cene, followed by a substitution of the SnMe3 by GaMe2
groups. We could show in a separate control that tri-
methylgallium does not react with 1,1′-bis(trimethyl-
stannyl)ferrocene. Thus we can exclude this pathway.
The first step in the observed sequence corresponds to
an electrophilic substitution reaction at a trichlorostan-
nyl-substituted carbon center of the ferrocene unit.
Str u ctu r a l F ea tu r es of 1. Yellow-orange crystals of
1 were grown from toluene/trimethylgallium solution at
room temperature. 1 crystallizes in the triclinic space
group P1h. The compound is a polymer that consists of
ferrocenediyl fragments bridged by GaMe2 groups. The
molecular Fe(C5H4GaMe2)2 units are present in trans-
conformation; this orientation allows the formation of
polymer strands which are arranged parallel to each
other and which are aligned parallel to the crystal-
lographic a-axis. Each strand is surrounded by six other
strands. A drawing of the structure of 1 including the
unit cell is presented in Figure 1; two molecular Fe-
(C5H4GaMe2)2 units from the polymeric structure of 1
are presented in Figure 2 as thermal ellipsoid plots.
Crystallographic data for 1 are collected in Table 1;
selected bond length and bond angles are given in Table
2.
F igu r e 2. Part of the solid state structure of 1, thermal
ellipsoids at 50% probability.
It is interesting to regard in more detail the bridging
GaMe2 units in order to compare the bonding situation
in polymeric 1 with that of dimeric [(η5-C5H5)Fe(η5-C5H4-
GaMe2)]2.4a In the latter, two ferrocenyl groups are
bridged by two GaMe2 units via carbon atoms of the
substituted cyclopentadienyl ring. A closer inspection
shows the presence of a weakly bonded dimer with two
short (1.992(5) Å) and two long (2.587(5) Å) Ga-C
bonds. In contrast, an even more weakly bonded dimer
with a highly asymmetric Ga2C2 unit is present in 1 (see
Figure 2). The Ga-Ga distance of 3.044 Å does not
indicate significant metal-metal interaction.
Regarding the Ga(1)Me2 group a strong bending of
the Ga(1)-C(1) vector out of the Cp plane (dip angle
R ) 25.7°; see Figure 3) is observed. The Ga(1)-Fe(1)
distance of 3.112(3) Å indicates attractive interactions
between the electron-rich Fe(1) atom and the electron-
deficient Ga(1) atom (empty p orbital). The Fe-Ga
interaction can be compared with Fe-B interactions in
borylferrocenes12 and with Fe-C+ interactions in fer-
rocenyl carbocations13 (Table 3). In comparison, the Ga-
(1)-C(1) vector of 1 shows the greatest dip angle. The
(12) (a) Wrackmeyer, B.; Do¨rfler, U.; Milius, W.; Herberhold, M.
Polyhedron 1995, 11, 1425. (b) Appel, A.; J a¨kle, F.; Priemeier, T.;
Schmid, R.; Wagner, M. Organometallics 1996, 15, 1188.
(11) An excess of trimethylgallium has been used to inhibit ther-
molysis reaction of 1 by elimination of trimethylgallium.5

3020 Organometallics, Vol. 21, No. 14, 2002
Althoff et al.
for gallium organyls.14 The Ga(2A)-C(1) bond distance
(2.410(2) Å) is among the longest gallium-carbon
distances reported. The Ga(2A) atom is distorted tet-
rahedrally coordinated (C(6A)-Ga(2A)-C(13A)/C(14A)
angle sum 352°; ideal tetrahedral angle sum ) 328.5°).
We assume that the electron deficiency at Ga(2A) is
compensated to a small extent by electron donation from
the Fe(1A) atom.
The C(1)-Ga(2A)-C(6A) unit is mainly responsible
for the intermolecular contact between the ferrocenediyl
units and represents an asymmetric electron-deficient
bond. The molecular structure of 1 may even be inter-
preted to possess only one bridging GaMe2 unit, as
demonstrated by the inspection of bond length and bond
angles within the CpGaMe2 units.
Ta ble 1. Cr ysta llogr a p h ic Da ta for 1 a n d
[1‚P h en a zin e]n
1
[1‚phenazine]
empirical formula
fw
C
14H20FeGa2
C26H28FeGa2N2
563.79
383.59
cryst color, habit
cryst size, mm3
temperature, K
wavelength, Å
cryst syst, space
group
yellow-orange needles
0.16 × 0.06 × 0.04
100(2)
0.71073
triclinic P1h
green plate
0.27 × 0.12 × 0.02
100(2)
0.71073
triclinic P1h
unit cell dimens
a ) 7.28300(10) Å
b ) 8.7910(2) Å
c ) 12.3490(3) Å
R ) 74.3810(8)°
â ) 82.8000(8)°
γ ) 68.5920(10)°
708.59(3)
a ) 7.5320(5) Å
b ) 8.9050(5) Å
c ) 9.7850(6) Å
R ) 64.861(4)°
â ) 76.416(3)°
γ ) 73.120(3)°
563.81(6)
volume, Å3
Z
NMR Sp ectr oscop y of 1. The solubility of 1 in donor
solvents (Do), for example pyridine and THF, stems
from the formation of monomeric adducts [1‚2Do], which
have been characterized using NMR spectroscopy (eq
3). 1H NMR spectroscopic data for [1‚2Py] and [1‚2THF]
are given in Table 4.
2
1
density (calcd),
1.798
1.660
Mg/m3
θ range for data
collection, deg
no. of reflns
collected
3.01-29.95
3.27-24.96
8073
3657
no. of indep reflns 4101 (Rint ) 0.0304)
1947 (Rint ) 0.049)
R1 ) 0.0370,
wR2 ) 0.0798
1537
final R indices
[I>2σ(I)]
R1 ) 0.0293,
wR2 ) 0.0576
3199
no. of reflns with
I>2σ(I)
R indices (all data) R1 ) 0.0488,
R1 ) 0.0539,
wR2 ) 0.0869
144
wR2 ) 0.0632
234
no. of params
largest diff peak
and hole, e Å-3
remarks
0.837 and -0.5
0.426 and -0.481
hydrogens were refined
isotropically
Electr och em istr y of 1. A cyclic voltammogram of
[1‚2Py] was recorded using pyridine as solvent and the
supporting electrolyte tetrabutylammonium fluoride
(TBAPF). The reversible oxidation potential of [1‚2Py]
in pyridine is E1/2 ) -370 mV, and the peak separation
is 165 mV. The corresponding boron compound Fe(η5-
C5H4BMe2)2 has a lower oxidation potential of E1/2
)
-510 mV in pyridine.15 This effect can be explained by
the higher electron-donating ability of the BMe2‚Py
group compared with that of the GaMe2‚Py group. While
the electron-donating ability of the BMe2‚Py group is
approximately equal to the positive inductive effect of
the five methyl groups in the pentamethylcyclopenta-
dienyl (Cp*) ligand,10a the GaMe2‚Py group is a consid-
erably weaker electron donor.
F igu r e 3. Dip angle R.
Ga(1)-C(1) bond distance of 1.978(2) Å and the Ga-
CMe bond distances are typical for gallium organyls.14
The Ga(1)-C(6A) distance of 2.775(2) Å indicates only
a very weak interaction between these two atoms, if at
all. Consequently, the C-Ga(1)-C angle sum is 359°,
as expected for a gallium atom that remains coordinated
in a trigonal planar fashion (sp2-hybridization). We
assume that the electron deficiency at Ga(1) is compen-
sated by electron donation from the Fe(1) center. With
reference to the Ga(1)-C(1) bond distance and the dip
angle, there may be only negligible electon donation
from the Cp π-system (C(1)-C(5)).
Regarding the Ga(2)Me2 group, we follow Figure 2
and look in more detail at the environment of the
equivalent Ga(2A)Me2 group. One can observe a com-
parably weaker bending of the Ga(2A)-C(6A) vector out
of the Cp plane (dip angle R ) 11.6°) and a longer Ga-
(2A)-Fe(1A) distance of 3.419(3) Å. This finding indi-
cates a weaker Fe(1A)-Ga(2A) interaction than ob-
served for Fe(1)-Ga(1). The Ga(2A)-C(6A) bond distance
of 1.989(2) Å and the Ga-CMe bond distances are typical
Syn th esis a n d Str u ctu r a l F ea tu r es of [1‚P h en a -
zin e]n . The coordination polymer [1‚phenazine]n was
prepared from stoichiometric amounts of 1 and phena-
zine. On heating in toluene, a yellow solution was
formed, which presumably contains the monomeric
compound [1‚phenazine] and some oligomeric species.
Because of the very low solubility of 1 in toluene, the
reaction had to be carried out in dilute solution. After
cooling to room temperature, the color of the solution
changed to green and small quantities of dark green
crystals were formed during a few days (eq 4).
[1‚phenazine]n crystallizes in the triclinic space group
P1h. A drawing of the structure of [1‚phenazine]n includ-
ing the unit cell is presented in Figure 4. Figure 5 shows
the repeating unit of the polymer structure represented
by one phenazine and by one digallylferrocene molecule.
(13) Kreidlin, A. Z.; Dolgushin, F. M.; Yanovsky, A. I.; Kerzina, Z.
A.; Petrovskii, P. V.; Rybinskaya, M. I. J . Organomet. Chem. 2000,
616, 106.
(15) Fe(η5-C5H4BMe2)2 was prepared using a literature procedure.2b
Electrochemical analysis was effected as described in the general
comments of the Experimental Section.
(14) Cambridge Crystallographic Structure Database.

The First 1,1′-Digallylferrocene
Organometallics, Vol. 21, No. 14, 2002 3021
Ta ble 2. Selected Dista n ces (Å) a n d An gles (d eg) for 1
Ga(1)-C(1)
Ga(1)-C(6A)
Ga(1)-C(11)
Ga(1)-C(12)
Ga(1)-Fe(1)
Ga(2A)-C(1)
Ga(2A)-C(A6)
Ga(2A)-C(A13)
Ga(2A)-C(A14)
Ga(2A)-Fe(1A)
Fe-C
1.978(2)
2.775(2)
1.965(3)
1.957(2)
3.112(3)
2.410(2)
1.989(2)
1.969(2)
1.974(2)
3.419(3)
2.052(2)-2.077(2)
3.044(3)
C(1)-Ga(1)-C(11)
C(1)-Ga(1)-C(12)
C(11)-Ga(1)-C(12)
C(6A)-Ga(2A)-C(13A)
C(6A)-Ga(2A)-C(14A)
C(13A)-Ga(2A)-C(14A)
∑C-Ga(1)-C
115.47(10)
117.61(10)
125.64(12)
117.35(11)
113.20(10)
121.65(12)
359
352
25.7(1)
11.6(1)
∑C-Ga(2A)-C
Ga(1)-C(1)-CpCentroid
Ga(2A)-C(6A)-CpCentroid
Ga-Ga
Ta ble 3. Dip An gle r
-
1 Ga(1)
1 Ga(2)
11.6°
Ta ble 4. 1H NMR Da ta
solvent δ(Ga-Me) δ(CCp-H) δ(CCp-H)
pyridine-d5
CpFe(C5H4BBr2)
Fe(C5H4BBr2)2
10.2°
CpFe(C5H4CH2)+ BF4
23.6°
R
25.7°
18.9°
compound
1‚2Py-d5
0.19
4.38
3.86
4.58
4.08
1‚2THF-d8 THF-d8
-0.27
F igu r e 5. Part of the solid state structure of [1‚phena-
zine]n, thermal ellipsoids at 50% probability.
Ta ble 5. Selected Dista n ces (Å) a n d An gles (d eg)
for [1‚P h en a zin e]n
Ga(1)-C(1) 1.971(4)
Ga(1)-C(6) 1.980(4)
Ga(1)-C(7) 1.975(4)
Ga(1)-N(1) 2.408(3)
C(1)-Ga(1)-C(6)
C(1)-Ga(1)-C(7)
C(6)-Ga(1)-C(7)
N(1)-Ga(1)-C(1)
112.51(19)
115.48(17)
120.69(19)
106.95(14)
98.56(16)
98.81(15)
349
Fe-C
2.047(4)-2.070(4) N(1)-Ga(1)-C(6)
N(1)-Ga(1)-C(7)
∑C-Ga(1)-C
Ga(1)-C(1)-CpCentroid
9.5(2)
surrounded by ferrocenediyl units, so that π-stacking
interactions between the phenazine rings cannot arise.
The Ga-CMe bond distances are comparable to those
in 1. The Ga-N bond distance of 2.408(3) Å is longer
than that found in other donor-acceptor adducts formed
from sp2-nitrogen donors and three-coordinated gallium
acceptors.14 This finding is consistent with the low
basicity of phenazine (pKa ) 1.39; in water 15 °C).16 The
angle sum of 349° within the GaC3 unit reveals only a
small degree of pyramidalization of the Ga centers (ideal
tetrahedral angle sum ) 328.5°). This observation also
explains the weak Ga-N interaction. The Ga(1)-
C(9A)-Cpcentroid dip angle R ) 9.5(2)° indicates attrac-
tive Ga-Fe interactions. Competition between Ga-Fe
and Ga-N interactions may be another cause for the
observed small pyramidalization.
F igu r e 4. Solid state structure of [1‚phenazine]n, including
the unit cell.
[1‚phenazine]n (green) shows a clearly different color
in comparison with 1 (orange). This effect may be caused
by charge-transfer interactions between the ferrocene-
diyl units and the phenazine units. A similar phenom-
enon has been observed for Fe(η5-C5H4BMe2)2 (red-
brown) and for the polymeric compounds [Fe(η5-C5H4-
BMe2)2L]n (L ) 4,4′-bipyridyl (purple) and pyrazine
(green)).10a,b
Crystallographic data for [1‚phenazine]n are collected
in Table 1; selected bond length and bond angles are
given in Table 5.
[1‚phenazine]n consists of polymer strands arranged
parallel to each other and aligned parallel to the
crystallographic a-c-diagonal. The ferrocenediyl units
are fixed in trans conformation. Each strand is sur-
rounded by four other polymer strands. The strands are
displaced in such a way that each phenazine ring is
Su m m a r y. Compound 1 was prepared from the
reaction of 1,1′-bis(trichlorostannyl)ferrocene with an
(16) Perkampus, H.-H.; Ro¨ssel, T. Z. Elektrochem. 1958, 62, 94.

3022 Organometallics, Vol. 21, No. 14, 2002
Althoff et al.
all components had dissolved. On cooling to room temperature,
1 formed as an orange, microcrystalline solid. The supernatant
solution was decanted, and the solid residue was washed with
hexane (or toluene) and dried in a vacuum, yield 1.20 g (3.13
excess of trimethylgallium. Our findings show that 1 is
a polymer in which ferrocendiyl units and dimethylgal-
lium groups are connected by electron-deficient bonds.
As indicated by the formation of the coordination
polymer [1‚phenazine]n, 1 can serve as a novel compo-
nent in supramolecular chemistry. A similarity in the
coordination behavior of 1 and Fe(η5-C5H4BMe2)2 can
be expected.10
We are currently trying to prepare supramolecular
structures using 1, 2, and 3 as building blocks. First
results show that all three compounds can successfully
be used in coordination polymer synthesis.
1
mmol; 86%). H NMR (pyridine-d5): δ 0.19 (12 H; CH3), 4.38
(4 H; ring C2/5-H or C3/4-H), 4.58 (4 H; ring C2/5-H or C3/4-
1
H). H NMR (THF-d8): δ -0.27 (12 H; CH3), 3.86 (4 H; ring
C2/5-H or C3/4-H), 4.08 (4 H; ring C2/5-H or C3/4-H). 13C NMR
(pyridine-d5): δ 6.6 (CH3), 70.8 (ring C2/5 or C3/4), 75.3 (ring
C2/5 or C3/4), 76.2 (C1-GaMe2). Anal. Calcd for C14H20FeGa2
(M ) 383.59 g mol-1): C, 43.84; H, 5.26. Found: C, 42.47; H,
4.77.19 CV: E1/2 ) -370 mV (peak separation 165 mV).
Compound 1 is very air sensitive.
SnMe4 and MexGaCl3-x could be identified in the reaction
mixture by NMR spectroscopy. 1H NMR (CDCl3): δ 0.14
(SnMe4), 0.26 (br, Me2GaCl/MeGaCl2). 119Sn NMR (CDCl3): δ
0.8 (SnMe4).
Exp er im en ta l Section
Gen er a l Com m en ts. All manipulations were carried out
under purified argon atmosphere using standard Schlenk
techniques. The solvents were commercially available, purified
by conventional means, and distilled immediately prior to use.
The NMR spectra were recorded using a Bruker Avance DRX
500 spectrometer (1H 500.1 MHz, 13C 125.8 MHz, 119Sn 186.5
MHz). Chemical shifts are reported in ppm and were refer-
enced to the solvent resonances as internal standard. The
elemental analyses were performed by the Microanalytical
Laboratory Beller, Go¨ttingen. The cyclic voltammogram was
recorded on an EG&G potentiostat, Model 273A, controlled by
M 250/270 software. The supporting electrolyte was tetrabu-
tylammonium fluoride (TBAPF), which was purchased from
Fluka and used without further purification. The electrolyte
concentration was 0.1 M. The voltammetric measurements
were performed using a platinum-disk electrode (d ) 2 mm),
which was polished prior to use. Potentials were calibrated
by the method of Gagne´ and are quoted versus the ferroce-
nium-ferrocene couple as internal standard.17 A platinum wire
was used as a counter electrode.
P r ep a r a tion of [1‚P h en a zin e]n . Phenazine (47 mg, 0.26
mmol) and 1 (100 mg, 0.26 mmol) were charged in a Schlenk
flask. Toluene (10 mL) was added, and the suspension was
heated to ca. 100 °C until a yellow solution had formed. The
reaction mixture was allowed to cool to room temperature.
After a few days the color of the solution changed to green,
and dark green, X-ray quality crystals formed, yield 31 mg
(0.05 mmol; 21%).20 The crystals were insoluble in all nondonor
solvents. Anal. Calcd for C26H28N2FeGa2 (M ) 563.81 g mol-1):
C, 55.39; H, 5.01; N, 4.97. Found: C, 55.42; H, 5.13; N, 4.89.
Ack n ow led gm en t. The support of this work by the
Deutsche Forschungsgemeinschaft, the Universita¨t
Bielefeld, and the Fonds der Chemischen Industrie is
gratefully acknowledged. We thank Professor Lorberth,
University of Marburg, for a gift of trimethylgallium.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data, positional and thermal parameters, and bond lengths
and angles; 1H and 13C NMR spectra. This material is available
free of charge via the Internet at http://pubs.acs.org.
Sta r tin g Ma ter ia ls. 1,1′-Bis(trichlorostannyl)ferrocene was
prepared using a literature procedure.18
P r ep a r a tion of 1,1′-Bis(d im eth ylga llyl)fer r ocen e (1).
Trimethylgallium ((pyrophoric!) 4.17 g, 36.3 mmol) was added
to a suspension of 1,1′-bis(trichlorostannyl)ferrocene (2.30 g,
3.63 mmol) in toluene (5 mL) in a Schlenk flask. The reaction
mixture was heated to 68 °C in the tightly closed flask until
OM020185D
(19) The reactivity of 1 toward air and moisture contributes to the
less than ideal elemental analysis (the same problem has been observed
for dimethylgallylferrocene4a). In the MS of 1, the M+ peak was not
observed; interestingly, the condensation product 3+ could be detected.
The purity of 1 was established by high-resolution 1H and 13C NMR
spectroscopy in donor solvents.
(17) Gagne´, R. R.; Koval, C. A.; Lisensky, G. C. Inorg. Chem. 1980,
19, 2854.
(18) Herberhold, M.; Milius, W.; Steffl, U.; Vitzithum, K.; Wrack-
meyer, B.; Herber, R. H.; Fontani, M.; Zanello, P. Eur. J . Inorg. Chem.
1999, 145.
(20) No attempt to optimize the reaction has been made.