Preparation and characterization of various N-substituted-2-aza-[3]-ferrocenophanes and their chemical and electrochemical properties

Article abstract of DOI:10.1016/S0020-1693(99)00369-2

RuCl₂(PPh₃)₃ catalyzed condensation of 1,1′-ferrocenedimethanol with primary amines afforded N-alkyl- or N-aryl-2-aza-[3]-ferrocenophanes which were characterized by ¹H and ¹³C NMR spectra. X-ray crystallography of N-(4-butylphenyl)-2-aza-[3]-ferrocenophane unequivocally revealed its mononuclear structure. The N-C (aryl) bond distance is shorter than the N-CH₂ single bond due to extension of π-conjugation of the aromatic ring to the nitrogen atom. N-Hexyl-2-aza-[3]-ferrocenophane reacts with methyl iodide to give the N-methylated product which was characterized by NMR spectroscopy and X-ray crystallography. N-Aryl-2-aza-[3]-ferrocenophanes exhibited reversible redox between ferrocene and ferrocenium cations and an irreversible oxidation peak at a higher oxidation potential.

Full text of DOI:10.1016/S0020-1693(99)00369-2

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 296 (1999) 176–182
Preparation and characterization of various
N-substituted-2-aza-[3]-ferrocenophanes and their chemical and
electrochemical properties
Tatsuaki Sakano, Hidetake Ishii, Isao Yamaguchi, Kohtaro Osakada *,
Takakazu Yamamoto
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503 226-8503, Japan
Received 15 June 1999; accepted 3 August 1999
Abstract
RuCl2(PPh3)3 catalyzed condensation of 1,1%-ferrocenedimethanol with primary amines afforded N-alkyl- or N-aryl-2-aza-[3]-
1
ferrocenophanes which were characterized by H and 13C NMR spectra. X-ray crystallography of N-(4-butylphenyl)-2-aza-[3]-fer-
rocenophane unequivocally revealed its mononuclear structure. The N–C (aryl) bond distance is shorter than the N–CH2 single
bond due to extension of p-conjugation of the aromatic ring to the nitrogen atom. N-Hexyl-2-aza-[3]-ferrocenophane reacts with
methyl iodide to give the N-methylated product which was characterized by NMR spectroscopy and X-ray crystallography.
N-Aryl-2-aza-[3]-ferrocenophanes exhibited reversible redox between ferrocene and ferrocenium cations and an irreversible
oxidation peak at a higher oxidation potential. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Ruthenium; Ferrocenophane; Electrochemistry; Condensation
gives its dimer 6ia initial formation of the cation radical
and ensuing dehydrogenative coupling. (Scheme 1) [2].
1. Introduction
Ferrocene derivatives with an amino group containing
Functionalized ferrocenes have high stability and
a substituent on the Cp ring were studied electrochemi-
unique chemical and electrochemical properties, which
cally and revealed the redox of the Fe center and
are important in their use as various materials such as
oxidation of the amino group [3].
modified electrodes, electrically conductive polymers,
and magnetic materials [1]. The electron releasing group
Ferrocenophanes with a rigid bivalve structure are a
class of functionalized ferrocenes that have attracted
attached to the cyclopentadienyl group serves to lower
recent attention. [1]-Silaferrocenophanes and [1]-phos-
the oxidation potential of the Fe(II) center. The func-
phaferrocenophanes undergo ring opening polymeriza-
tional group, which undergoes electrochemical reaction
tion on heating to give ferrocene containing polymer
in itself, on the cyclopentadienyl ring will make the
redox behavior more complicated. Aryl amine is sus-
ceptible to electrochemical oxidation and subsequent
chemical reaction and undergoes anodic oxidation to
generate cation radicals and dications which cause fur-
ther decomposition or transformation of the organic
molecules. For example, the electrochemical oxidation
of N,N-dimethylaniline in an acidic buffer solution
* Corresponding author. Tel.: +81-45-924 5225; fax: +81-45-924
5276.
E-mail address: kosakada@res.titech.ac.jp (K. Osakada)
Scheme 1.
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00369-2

T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
177
Table 1
Yields, color, and analytical results of N-alkyl (or aryl)-2-aza-[3]-ferrocenophanes a
Amine
Product
Yield (%)
Color
Elemental analysis (%) b
C
H
N
4-Methylaniline
4-Butylaniline
4-t-Butylaniline
4-Hydroxyaniline
Hexylamine
1
2
3
4
5
6
7
68
63
58
56
40
70
58
orange
orange
orange
orange
pale yellow
orange
orange
72.16 (71.94)
73.87 (73.54)
72.98 (73.54)
67.73 (67.72)
69.46 (69.36)
71.99 (71.94)
72.49 (72.52)
5.84 (6.04)
6.73 (7.01)
7.00 (7.01)
5.37 (5.36)
8.10 (7.95)
6.12 (6.04)
6.12 (6.39)
4.42 (4.42)
3.89 (3.90)
3.85 (3.90)
4.39 (4.42)
4.50 (4.25)
4.42 (4.42)
3.91 (4.23)
Benzylamine
4-Methylbenzylamine
a The reactions were carried out by heating the NMP solution for 24 h at 180°C.
b Required values are in parentheses.
2. Results and discussion
materials [4,5]. Pentaoxo-[13]-ferrocenophane with a
crown ether unit in the molecule includes alkali cation
selectivity. The inclusion of alkali metal ion in the
crown ether unit makes the ferrocene/ferrocenium re-
dox potential more positive, which is utilized as an ion
sensor [6]. On the other hand, there have been fewer
studies on structure and properties of aza-[n]-ferro-
cenophanes than other ferrocenophanes. 2-Aza-[4]-fer-
rocenophanes were prepared by several step reactions
starting from oxoferrocenophane, but are unstable at
room temperature [7]. The reaction of 1,1%-fer-
rocenedimethanol with aryl isocyanate gave N-aryl-2-
aza-[3]-ferrocenophane in low yields [8]. N-Methyl-
2-aza-[3]-ferrocenophane was recently prepared by Ple-
nio et al. who reported preparation of N-methyl-2-aza-
[3]-ferrocenophane from condensation of [1,1%-ferro-
cenediylbis(methylene)]bis(pyridinium) tosylate with
methylamine in 35% yields [3]. The substrate in the
reaction is derived from 1,1%-ferrocenedimethanol 6ia
several reaction steps. An alternative route to the 2-aza-
[3]-ferrocenophane from direct condensation of 1,1%-fer-
rocenedimethanol with amine would provide a more
efficient route to supply various ferrocenophane deriva-
tives.
2.1. Preparation, characterization and chemical
properties of the azaferrocenophane
1,1%-Ferrocenedimethanol reacts with 4-methylaniline
in the presence of RuCl2(PPh3)3 catalyst at 180°C to
give N-(4-methylphenyl)-2-aza-[3]-ferrocenophane (1) in
68% yield. Similar reactions with 4-butylaniline, 4-t-
butylaniline, 4-hydroxyaniline, hexylamine, benzyl-
amine, 4-methylbenzylamine afford the corresponding
N-substituted 2-aza-[3]-ferrocenophanes 2–7, as shown
in Eq. (1). Yields and analytical results of the products
are summarized in Table 1.
(1)
4-Hydroxyaniline gives the ferrocenophane with an OH
group in a moderate isolated yield, indicating that the
phenolic OH group of the substrate is less reactive than
1
that of 1,1%-ferrocenedimethanol. Fig. 1 shows the H
and 13C{1H} NMR spectra of 2 in CDCl3. A pair of
1
doublets at l 4.18 and 4.06 in the H NMR spectrum
Recent progress in synthetic organic reactions using
Groups 8–10 metal complexes as the catalyst has en-
abled condensation of primary alcohols with amines to
form a C–N bond under neutral conditions [9,10].
Extension of this reaction to primary amine and 1,1%-
ferrocenedimethanol would provide a general pre-
paration method for N-alkyl- or N-aryl-2-aza-[3]-
ferrocenophanes.
are assigned to the hydrogens attached to the cyclopen-
tadienyl rings. Positions of the cyclopentadienyl carbon
signals are similar to (N,N-dimethyamino)methyl-
1
ferrocene. The CH2N group gives rise to a single H
NMR resonance at l 3.80 and the 13C NMR signal at
l 46.9. Appearance of a single peak due to CH2N
hydrogens suggests rapid inversion of the 4-butylphenyl
group at the nitrogen atom. Other H and 13C NMR
1
In this paper we report results of the reaction using
aliphatic and aromatic amines to afford N-substituted-
2-aza-[3]-ferrocenophanes, as well as their structure and
electrochemical properties. The reversible redox behav-
ior of ferrocenophanes is discussed based on several
reactions of ferrocenophanes with a Lewis acid as a
proton source and methylated cation complex. Part of
this work has been reported in a preliminary form [11].
signals are assigned reasonably to the butylphenyl
group bonded to the nitrogen. As shown in Table 2, the
1H and 13C{1H} NMR spectra of 1 and 3–7 also show
signals at l 2.8–3.9 (1H) and l 46–53 (13C) due to the
CH2 group attached to the nitrogen atom and a Cp
ring.
In order to exclude another possible structure con-
taining two 1,1%-ferrocenediyl units bridged by the

178
T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
CH2N(R)CH2 groups, X-ray crystallographic analysis
was carried out. Fig. 2 depicts the molecular structure
of 3. Two Cp rings are almost parallel and are at
staggered positions with tilt angles close to 0°, similar
to the reported structures of [3]-ferrocenophanes
[12,13]. The angles between the N–CH2 bond and Cp
plane are about 59° which is larger than those of
[1]-phosphaferrocenophanes [5]. Table 3 summarizes
selected bond distances and angles of 3, which are
similar to those of 2 [11]. The N1–C13(aryl) bond
,
distance (1.38(1) A) is significantly shorter than those of
,
N–CH2 bonds (1.44(1) and 1.46(1) A). The different
N–C single bond distance and enlarged H2C–N–
C(aryl) bond angles (\120°) suggest partial sp2 charac-
ter of the nitrogen atom caused by conjugation of the
lone pair of the nitrogen atom and p-orbital of the
phenyl ring.
The reaction of N-hexyl-2-aza-[3]-ferrocenophane 5
with CH3I at room temperature leads to N-methylation
as shown in Eq. (2).
Fig. 1. (a) 1H and (b) 13C NMR spectra of N-4-butylphenyl-2-aza-[3]-
ferrocenophane (CDCl3, 25°C).
(2)
Table 2
NMR data of ferrocenophanes 1-7 a
1H NMR
13C NMR
Cp rings
CpCH2N Others
1 4.06 (s)
3.80 (s) 2.28 (3H, s, CH3),
20.0(CH3), 46.8 (CH2N),
4.18 (s)
7.07 (d, C6H4, J=8 Hz)
69.1 and 70.0 (CH in C5H4), 84.6 (C–CH2N),
114.5, 126.9, 29.9, and 147.6
2 4.06 (d, J=2 Hz) 3.80 (s) 0.93 (3H, t, CH3), 1.38 (2H, tq, CH2, J=7 Hz)
14.0(CH3), 22.4 (CH2), 33.9 and 34.6 (CH2),
4.18 (d, J=2 Hz) 1.59 (2H, tt, CH2, J=8 Hz), 2.54 (2H, t, CH2Ph, J=8 Hz) 46.9 (CH2N), 69.1 and 70.0 (CH in C5H4),
6.93 and 7.07 (4H, d, C6H4, J=8 Hz)
3 4.07 (d, J=2 Hz) 3.81 (s) 1.32 (9H, ts, CH3),
84.6 (C–CH2N), 114.7, 129.2, 132.2, and 147.9
31.5 (CH3), 33.8 (CCH3), 47.08 (CH2N),
69.1 and 70.0 (CH in C5H4), 84.7 (C–CH2N),
114.4, 126.1, 140.6, and 147.7
4.19 (d, J=2 Hz)
6.93 and 7.23 (4H, d, C6H4, J=8 Hz)
4 4.08 (d, J=1 Hz) 3.69 (s) 3.69 (1H, s, OH),
4.18 (d, J=1 Hz)
5 4.07 (s)
4.08 (s)
6.80 and 6.93 (4H, d, C6H4, J=5 Hz)
2.88 (s) 0.92 (3H, t, CH3), 1.36 (6H, br, CH2)
1.59 (2H, tt, CH2, J=10, 7 Hz),
14.1(CH3), 22.7 (CH2), 27.2, 27.6, 31.8 (CH2),
52.2 (CH2N), 57.8 (CH2), 69.0 and 69.8 (CH
in C5H4), 83.9 (C–CH2N)
2.68 (2H, t, CH2, J=7 Hz)
6 4.07 (d, J=2 Hz) 3.86 (s) 2.91 (2H, s, =NCH2), 7.27 (2H, d, ortho, J=6 Hz)
4.12 (d, J=2 Hz)
7.36 (2H, dd, meta, J=6, 7 Hz), 7.44 (21H, d, para,
J=7 Hz)
7 4.07 (d, J=2 Hz) 3.82 (s) 2.35 (3H, ts, CH3), 3.82 (2H, s, NCH2Ph)
21.1 (CH3), 52.0 (CH2N), 61.7 (NCH2Ph),
69.0 and 69.8 (CH in C5H4), 83.67 (C–CH2N),
128.5, 128.9, 133.6, and 136.5
4.11 (d, J=2 Hz)
7.15 and 7.32 (4H, d, C6H4, J=8 Hz)
a Measured at 25°C in CDCl3.

T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
179
,
mon N–C single bond (1.44 A), probably due to posi-
tive charge at the nitrogen atom. A similar elongation
of the N–C single bonds was observed in bismethylated
2-aza-[3]-ferrocenophanes having BF−4 as the counter
anion [3].
2.2. Electrochemical beha6ior of the ferrocenophanes
The obtained ferrocenophanes are stable toward air
but are electrochemically oxidized easily as described
below. The redox potentials of neutral ferrocenophanes
1–7 and of methylated derivatives are summarized in
Table 4. Fig. 4 depicts cyclic voltammograms of 1 and
7 in MeCN solutions. Two redox peaks (I and II) of 1
are observed at E1/2= +0.08 and +0.69 V as shown
in Fig. 4(a). The reversible oxidation and reduction
peaks are close to the potential of ferrocene and as-
signed to the redox between the ferrocene and ferroce-
nium cations. The second irreversible peak of 1 is
assigned to oxidation of the initial oxidation product.
Scheme 2 summarizes a plausible mechanism for the
oxidation of 1, 2, 4, and 5. The intermediate (A),
formed via the initial oxidation of the Fe(II) center of
the ferrocenophane, undergoes intramolecular electron
transfer to give A% having a Fe(II) center and nitrogen
with a radical cation character. Further oxidation ac-
companied by deprotonation at the nitrogen affords the
two-electron oxidation product (B). Similar two-step
electrochemical oxidation of cationic N,N-dimethyl-2-
aza-[3]-ferrocenophane was reported to occur at a
higher potential than N-methyl-2-aza-[3]-ferroceno-
phane. As depicted in Fig. 4(b), 7 exhibits redox be-
tween ferrocene and ferrocenium cations only. The
reason for the different electrochemical behaviors of 1,
2, 4, and 5, and 6 and 7 needs further elucidation.
In summary, several new N-substituted-2-aza-[3]-fer-
rocenophanes are easily obtained in moderate yields by
the Ru catalyzed cyclizative condensation of 1,1%-fer-
Fig. 2. An ORTEP drawing of N-4-t-butylphenyl-2-aza-[3]-ferro-
cenophane.
The N-methyl-[3]-ferrocenophane cation 8 was isolated
as its iodide in 68% yield. The 1H NMR spectrum
shows a peak at l 3.61 attributable to N–CH3 protons.
The N–CH2 hydrogen signal of the hexyl group of 8 is
at a lower magnetic field position (l 3.83) than the
corresponding signal of 5 (l 2.68). The hydrogens of
the CH2 group between the nitrogen atom and a Cp
ligand give signals at l 4.55, 4.59, and 4.66 in a 1:1:2
peak area ratio. The signal pattern and the lower
magnetic field position than 5 are ascribed to the
presence of quaternary nitrogen which makes the four
NCH2 hydrogens unequivalent. Fig. 3 depicts the
molecular structure of 8 determined by X-ray crystal-
,
lography. The N1–C14 bond distance (1.57(3) A) and
N–CH2 bond distances (N1–C11 1.50(2), N1–C12
,
1.55(2), N1–C13 1.49(3) A) are longer than the com-
Table 3
,
Selected bond distances (A) and angles (°) of 2 and 3
a
2
3 b
Bond distances
Fe–C1
Fe–C2
Fe–C3
Fe–C4
Fe–C5
Fe–C6
Fe–C7
Fe–C8
Fe–C9
Fe–C10
C1–C11
C6–C12
N1–C11
N1–C12
N1–C13
2.010(4)
2.042(4)
2.062(5)
2.051(5)
2.036(5)
2.009(4)
2.032(4)
2.065(5)
2.053(4)
2.036(4)
1.519(6)
1.514(6)
1.467(6)
1.464(6)
1.400(6)
2.011(9)
2.03(1)
2.06(1)
2.050(9)
2.02(1)
2.008(9)
2.033(9)
2.06(1)
2.05(1)
2.020(9)
1.52(1)
1.51(1)
1.44(1)
1.46(1)
1.38(1)
Fig. 3. An ORTEP drawing of N-hexyl-N-methyl-2-ammonium-[3]-fer-
,
Bond angles
C11–N1–C12
C11–N1–C13
C12–N1–C13
N1–C11–C1
N1–C12–C6
rocenophane iodide. Selected bond distances (A) and angles (°):
113.8(4)
120.7(4)
119.64)
115.4(4)
115.1(3)
113.6(8)
122.4(8)
121.8(8)
116.2(8)
114.8(7)
Fe1–C1 2.02(2), Fe1–C2 2.05(2), Fe1–C3 2.06(2), Fe1–C4 2.01(2),
Fe1–C5 2.01(2), Fe1–C6 1.95(2), Fe1–C7 2.05(2), Fe1–C8 2.04(2),
Fe1–C9 2.04(2), Fe1–C10 2.02(2), C1–C11 1.45(3), C6–C12 1.49(2)
N1–C11 1.50(2), N1–C12 1.55(2), N1–C13 1.49(3), N1–C14 1.57(3),
N1–C11–C1 116(2), C11–N1–C13 113(2), C12–N1–C13 111(1)
C11–N1–C14 103(1), C12–N1–C14 106(1), C13–N1–C14 109(2).
One of the two crystallographically independent molecules is shown.
Counter anions (I−) and hydrogen atoms are omitted for simplicity.
a Taken from Ref. [11].
b This work.

180
T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
Scheme 2.
rocenedimethanol with primary aromatic and aliphatic
amines. The reaction is applied to the synthesis of
various ferrocenophanes including that containing the
phenolic OH group. The obtained ferrocenophanes
exhibit reversible oxidation and reduction of the Fe(II)
center and subsequent oxidation of the ligand although
N-benzyl-azaferrocenophane does not undergo the
lat-ter oxidation. The rigid structure and unique
electrochemical properties of the compound suggest
their potential utility as new material.
containing 0.10 M Et4NBF4 with a Hokuto Denko
HA-501 galvanostat/potentiostat and Hokuto Denko
HB-104 function generator. The Ag/Ag+ reference
electrode was used. RuCl2(PPh3)3 [14] and
1,1%-ferrocenedimethanol [15] were prepared according
to the literature. Acetonitrile and 1-methyl-2-pyrrol-
idinone (NMP) were dried over CaH2, distilled, and
stored under nitrogen or argon. Et4NBF4 was
recrystallized from methanol before use.
3.2. Preparation of 1–7
3. Experimental
To an NMP (3 cm3) solution of RuCl2(PPh3)3 (67
mg, 0.070 mmol) were added 4-methylaniline (214 mg,
2.0 mmol) and then 1,1%-ferrocenedimethanol (492 mg,
2.0 mmol) at room temperature under nitrogen atmo-
sphere. The mixture was heated at 180°C. After 24 h
the solvent was removed under vacuum. The residue
was dissolved in ethyl acetate, and the insoluble pro-
3.1. General
Manipulations of RuCl2(PPh3)3 were carried out
under nitrogen or argon using the standard Schlenk
technique. The NMR spectra (1H and 13C) were
recorded on a JEOL EX-400 spectrometer at 25°C
unless otherwise stated. Elemental analyses were carried
out by a Yanaco MT-5 CHN autocorder. Cyclic
voltammetry was measured in an acetonitrile solution
Table 4
Redox potential of the ferrocenophanes a
Compound
1st
2nd
E1/2 (V)
E1/2 (V)
1
2
3
4
5
6
7
8
+0.08
+0.08
+0.04
+0.04
+0.04
+0.05
+0.04
+0.40 b
+0.04
+0.68
+0.72
+0.45
+0.44
+0.35
Ferrocene
a Measurement was carried out in a solution of ferrocenophane
(1 mM) in MeCN containing 0.10 M Et4NBF4 at 25°C. Potential is
referenced to Ag/Ag+. Sweep rate: 0.10 V s−1
.
Fig. 4. Cyclic voltammograms for oxidation of 1.0 mM solutions of
(a) 5 and (b) 7 in acetonitrile containing 0.10 M Et4NBF4 at 0.1 V
s−1 and 25°C.
b Reversible oxidation and reduction of the counter ion (I−) are
observed at −0.12 V.

T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
181
Table 5
out by using a program package teXsan for Windows.
The structures were solved by a direct method and
subsequent Fourier technique. All non-hydrogen atoms
were refined anisotropically. The hydrogen atoms were
located by assuming the ideal geometry and included in
the structure calculation without further refinement of
the parameters. Crystallographic data and details of
refinement are summarized in Table 5.
Crystal data and details of structure refinement of compounds 3 and
8
Compound
Formula
Molecular weight
Crystal system
Space group
3
C
359.29
8
22H25FeN
C19H28FeIN
453.19
monoclinic
P21/c (No. 14)
12.511(2)
11.098(4)
12.974(3)
99.05(2)
1178.9(7)
4
8.49
760
1.341
0.4×0.5×0.7
4301
monoclinic
P21/c (No. 14)
15.115(4)
11.873(6)
21.425(6)
90.21(2)
3845(2)
8
47.75
1712
1.517
0.7×0.8×1.0
9256
,
a (A)
,
b (A)
,
c (A)
i (°)
4. Supplementary material
3
,
V (A )
Z
Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC no. 133319 and 133320 for 3 and
8, respectively. Copies of this information may be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (Fax: +44-
1223-336-033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
v (Mo Ka) (cm−1
F(000)
)
Dcalc. (g cm−1
)
Crystal size (mm)
Unique reflections
Used reflections [I]2|(I)]
No. of variables
R
1579
212
0.066
0.073
2938
397
0.062
0.069
Rw
Acknowledgements
ducts were removed by filtration. The product in the
solution was purified by column chromatography (silica
gel; hexane:ethyl acetate=1:1) to give an orange solid
which was recrystallized from a chloroform-methanol
mixture to afford 1 as orange crystals (226 mg, 68%).
Ferrocenophanes 2–7 were prepared analogously.
This work was financially supported by a Grant-in-
aid for Scientific Research from the Ministry of Educa-
tion, Science, Sport and Culture, Japan.
References
3.3. Preparation of cationic complex 8
[1] A. Togni, T. Hayashi (Eds.),Ferrocenes, VCH, New York
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121. P.J. Peerce, A.J. Bard, J. Electroanl. Chem. 112 (1980) 97.
W.R. Cullen, J.D. Woolins, Coord. Chem. Rev. 39 (1981) 1. T.
Hayashi, M. Kumada, Acc. Chem. Res. 15 (1982) 395. J.S,
Miller A.J. Epstein, Angew. Chem., Int Ed. Engl. 33 (1994) 385.
[2] R.L. Hand, R.F. Nelson, J. Am. Chem. Soc. 96 (1974) 850. T.
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To N-hexyl-2-aza-[3]-ferrocenophane (5, 34 mg,
0.109 mmol) suspended in 3 cm3 of MeCN was added
MeI (31 mg, 0.218 mmol) at room temperature. Com-
plex 5 was instantly dissolved on stirring. After 18 h,
the crystalline product was separated from the solution
and collected by filtration. The resulting orange solid
was recrystallized from MeCN/Et2O (66mg, 68%) to
give 8. Anal. Calc. for C19H28FeIN (M=453.2): C,
50.35; H, 6.23; N, 3.09; I, 28.00. Found: C, 50.52; H,
5.70; N, 3.00; I, 28.07%. lH(CDCl3) 0.92 (3H, t, –CH3,
J=7 Hz), 1.38 (6H, br, –CH2(CH2)3CH3), 1.90 (2H, tt,
–CH2(CH2)3CH3, J=7 Hz), 3.61 (3H, s, –NCH3), 3.83
(2H, t, –NCH2, J=10 Hz), 4.29 and 4.32 (8H, Cp
ring), 4.55, 4.59, and 4.66 (4H, m, CpCH2N).
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3.4. X-ray structure analyses
Crystals of 3 and 8 suitable for X-ray diffraction
study were obtained by recrystallization from CHCl3/
MeOH and MeCN/Et2O, respectively, and mounted in
glass capillaries under argon. Data were collected at
23°C on a Rigaku AFC-5R automated four-circle dif-
fractometer equipped with monochromated Mo Ka
,
radiation (u=0.71073 A). Calculations were carried

182
T. Sakano et al. / Inorganica Chimica Acta 296 (1999) 176–182
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.