Synthesis of controlled π-extended conjugate nanostructures of 1,1′-ferrocene

Article abstract of DOI:10.1016/S0022-328X(01)00909-3

Synthesis of the (E,E)-1,1′-ferrocene nanostructures having controlled π-extended conjugation was satisfactory carried out starting of 1′-[2-(1,3-dioxolan)]-1-formylferrocene (1). The molecular unit (E)-1′-[2-(1,3-dioxolan)]-1-[β-(p-iodophenyl)ethenyl]ferrocene (2), was obtained in excellent yield by treatment of 1 with p-iodobenzyl triphenylphosphonium ylid followed by Z→E isomerization, catalyzed by iodine, in quantitative yield. Compound (E)-2 was transformed in (E)-1′-{2-(1,3-dioxolan)-1-[β-[4-(3-hydroxy-3-methyl-but-1-ynyl)-phenyl]-ethenyl}ferrocene, (E)-4, by palladium catalyzed cross-coupling with 2-methyl-but-3-yn-2-ol. (E)-4 gives (E)-1-[β-(4-ethynylphenyl)-ethenyl]-1′-[2-(1,3-dioxolan)]ferrocene (E)-5 by powder sodium hydroxide treatment. The molecular unit (E,E)-1-{β-[4-(β-(1′-formylferrocenyl)-ethenyl)-phenylethynyl]-phenyl]-ethenyl}-1′-formylferrocene, (E,E)-6, was synthesized by palladium catalyzed cross-coupling between the p-iodophenyl derivative (E)-2 and their ethynyl derivative (E)-5, in good yield. The (E,E)-1,1′-(p-iodophenyl)ethenyl ferrocene, (E,E)-7, was synthesized by reaction between 1,1′-diformylferrocene and the p-iodobenzyltriphenylphosphonium ylid, as a mixture of isomers which were purely isolated. Moreover, isomerization of the Z,Z and E,Z mixture to the E,E isomer, was induced by sunlight exposure, catalyzed by iodine, in quantitative yield. The (E,E)-1,1′-[β-(4-ethynylphenyl)-ethenyl]ferrocene, (E,E)-10, was synthesized in good yield, by palladium catalyzed cross-coupling of compound (E,E)-7 with 2-methyl-but-3-yn-2-ol, followed by powder sodium hydroxide treatment.

Full text of DOI:10.1016/S0022-328X(01)00909-3

Journal of Organometallic Chemistry 637–639 (2001) 230–239
www.elsevier.com/locate/jorganchem
Synthesis of controlled p-extended conjugate nanostructures of
,1%-ferrocene
1
Jos e´ -Gonzalo Rodr ´ı guez *, Sheila Pleite
Departamento de Qu ´ı mica Org a´ nica, C1, Facultad de Ciencias, Uni6ersidad Aut o´ noma, Cantoblanco, 28049 Madrid, Spain
Received 28 December 2000; received in revised form 2 February 2001; accepted 5 February 2001
Abstract
Synthesis of the (E,E)-1,1%-ferrocene nanostructures having controlled p-extended conjugation was satisfactory carried out
starting of 1%-[2-(1,3-dioxolan)]-1-formylferrocene (1). The molecular unit (E)-1%-[2-(1,3-dioxolan)]-1-[b-(p-iodophenyl)-
ethenyl]ferrocene (2), was obtained in excellent yield by treatment of 1 with p-iodobenzyl triphenylphosphonium ylid followed by
Z“E isomerization, catalyzed by iodine, in quantitative yield. Compound (E)-2 was transformed in (E)-1%-{2-(1,3-dioxolan)-1-[b-
[4-(3-hydroxy-3-methyl-but-1-ynyl)-phenyl]-ethenyl}ferrocene, (E)-4, by palladium catalyzed cross-coupling with 2-methyl-but-3-
yn-2-ol. (E)-4 gives (E)-1-[b-(4-ethynylphenyl)-ethenyl]-1%-[2-(1,3-dioxolan)]ferrocene (E)-5 by powder sodium hydroxide
treatment. The molecular unit (E,E)-1-{b-[4-(b-(1%-formylferrocenyl)-ethenyl)-phenylethynyl]-phenyl]-ethenyl}-1%-formylferrocene,
(
E,E)-6, was synthesized by palladium catalyzed cross-coupling between the p-iodophenyl derivative (E)-2 and their ethynyl
derivative (E)-5, in good yield. The (E,E)-1,1%-(p-iodophenyl)ethenyl ferrocene, (E,E)-7, was synthesized by reaction between
,1%-diformylferrocene and the p-iodobenzyltriphenylphosphonium ylid, as a mixture of isomers which were purely isolated.
1
Moreover, isomerization of the Z,Z and E,Z mixture to the E,E isomer, was induced by sunlight exposure, catalyzed by iodine,
in quantitative yield. The (E,E)-1,1%-[b-(4-ethynylphenyl)-ethenyl]ferrocene, (E,E)-10, was synthesized in good yield, by palladium
catalyzed cross-coupling of compound (E,E)-7 with 2-methyl-but-3-yn-2-ol, followed by powder sodium hydroxide treatment.
©
2001 Elsevier Science B.V. All rights reserved.
Keywords: Ferrocenes; Acetylenes; Diynes; (E)- and (Z)-isomers; Acetal; Biphenyl; Coupling reactions
1
. Introduction
ments have large second-order nonlinearities [8].
Molecules with p donor–acceptor interactions, such as
ferrocene or derivatives, are promising candidates
to show these properties. Thus, Buckminsterfullerene
C60 cocrystallizes with ferrocene to isolate the
C (ferrocene) complex stabilized by weak intermolec-
ular charge transfer interactions [9]; the vinylferrocene
moiety has been used as a p-electron donor in several
compounds [10], with high second harmonic generation
(SHG) [11] efficiencies.
In this way (E)-1-ferrocenyl-2-(p-ethynylphenyl)-
ethene has been prepared for the polyene synthesis [12]
and their 1,3-diyne dimer for the topopolymerization
analysis to prepare electroactive and nonlinear optics
materials.
The use of molecular organic materials for conductor
and nonlinear optics applications is an area of consider-
able recent activity. Interest in these materials is due to
their inherent synthetic flexibility, which permits the
design of molecular properties [1].
Compounds containing ferrocene have been used in
electrochemistry and catalyst chemistry [2], as molecu-
lar sensors [3], and ferromagnets [4,5] and in nonlinear
optics [6,7]. It is now well established that molecular
structures with differences between ground-state and
excited-state dipole moments and large transition mo-
60
2
Preparation of double bond [13] or triple bond [14]
conjugate 1-ferrocenyl structures have been recently
reported.
*
Corresponding author. Tel.: +34-1-397-4715; fax: +34-1-397-
966.
E-mail address: gonzalo.rodriguez@uam.es (J.-G. Rodr ´ı guez).
3
0
022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00909-3

J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
231
sive crystallizations in hexane the E isomer was purely
isolated while in solution the Z isomer remained pure.
2.3. Z“E Isomerization of 1%-[2-(1,3-dioxolan)]-1-[i-
(p-iodophenyl)ethenyl]ferrocene (2)
The effort for the separation of the mixture of E and
Z isomers of 2 (E/Z, 5:2) by chromatographic methods
was unsuccessful, although both isomers were purely
isolated by successive crystallizations in hexane.
Moreover, in general the E isomer exhibits better
electrical and optical properties and, it was necessary to
planify a method for the preparation of the E by
conversion of the Z isomer taking in account the more
favourable thermodynamic stability.
Scheme 1. (i) BuLi, hexane, TMEDA, diethyl ether; (ii) DMF,
+
−
78 °C; (iii) (HOCH ) , H .
2 2
2. Discussion
Synthesis of the (E,E)-1,1%-ferrocene nanostructures
having controlled p-extended conjugation was satisfac-
tory carried out starting of 1%-[2-(1,3-dioxolan)]-1-
formylferrocene.
Chemical isomerization of the Z isomer was carried
out in hexane by exposure to the sunlight, with iodine
in catalytic amounts. Furthermore, after 24 h the Z“E
transformation was practically quantitative, although a
mixture of the expected 1,3-dioxolane derivative (E)-2
and the deprotected formyl derivative (E)-3 was iso-
2.1. Synthesis of 1%-[2-(1,3-dioxolan)]-1-formylferrocene
(
1)
The starting compound 1%-[2-(1,3-dioxolan)]-1-
1
lated, in a 1:3 ratio, respectively (by H-NMR) (Scheme
formylferrocene was prepared from 1,1%-diformylfer-
rocene [15] by treatment with 1,2-dihydroxyethane in
excess (20 equivalents) catalyzed by p-toluensulfonic
acid with good yield (60%); 1,1%-di[2-(1,3-diox-
olan)]ferrocene, was also isolated (20%) (Scheme 1).
2
).
By H-NMR the (E)-2 isomer shows the Cp–CHꢀ
and Ph–CHꢀ protons at 6.60 and 6.73 ppm as doublets
1
−
1
(
6
J=16.17 Hz; IR, 964 cm ), and the (Z)-2 isomer at
.36 and 6.33 ppm, respectively, as doublets (J=12.3
−
1
Hz; IR, 863 cm ).
2.2. Synthesis of (E)-1%-[2-(1,3-dioxolan)]-1-[i-(p-
The X-ray molecular structure of (E)-1-ferrocenyl-2-
iodophenyl)ethenyl]ferrocene (2)
(
p-iodophenyl)ethene was reported [16a]. The packing
of the molecules exhibits a short contact (3.63 A
,
)
The synthesis of compound (E)-2 was outlined as a
good synthon for the preparation of the 1,1% conjugate
acetylene compounds which can be transformed to the
corresponding diacetylenes and polyacetylenes [12],
which exhibit a more extended p-electronic conjugation.
Compound (E)-2 was prepared starting of 1-[2-(1,3-
dioxolan)]-1%-formylferrocene (1) with the p-iodobenzyl
triphenylphosphonium ylid [15], giving 2 as a mixture
of the E and Z isomers. The yield of the reaction
depends of the amount of the phosphonium salt and
the nature of the base used to prepare the ylid. Thus,
the reaction was optimized using two equivalents of the
phosphonium salt and three equivalents of potassium
tert-butoxide, giving 2 in good yield (87%), as a mix-
between the iodine atom and the p-cyclopentadienyl
ring system, of charge transfer type, being the iodine
atom the acceptor; accordingly the distances of the Fe
atom to the centroids of the cyclopentadienyl rings
were different, 1.635(1) and 1.665(1) A
found in 1,4-di(1-ferrocenyl)-1,3-butadiyne are similar
1.645(1) and 1.650(1) A [16b]).
,
, while these
(
,
2.4. Synthesis of (E)-1-[i-(4-ethynylphenyl)-ethenyl]-1%-
[2-(1,3-dioxolan)]ferrocene (5)
The catalytic cross-coupling reaction of haloarenes to
prepare the ethynyl derivatives, permits the extension of
the molecular conjugation.
1
ture of E and Z isomers (5:2, by H-NMR). By succes-
t
Scheme 2. (i) p-Iodobenzyltriphenylphosphonium bromide; KO Bu; (ii) I , sunlight.
2

232
J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
Scheme 3. (i) PdCl (PPh ) , Cu I , NEt , HCꢁC(CH ) –OH; (ii) NaOH, toluene, D; (iii) PdCl (PPh ) , Cu I , NEt ; (iv) AcOH, H O.
2
3 2
2 2
3
3 2
2
3 2
2 2
3
2
1
Thus, compound (E)-2 was transformed in (E)-1%-{2-
1,3-dioxolan)-1-[b-[4-(3-hydroxy-3-methyl-but-1-ynyl)-
main E,E and the E,Z (by H-NMR, 3:1), in practically
quantitative yield.
(
phenyl]-ethenyl}ferrocene (4) by cross-coupling reaction
with 2-methyl-but-3-yn-2-ol in presence of dichloro-
bis(triphenylphosphine) palladium and cuprous iodide
in triethylamine, in practically quantitative yield. Com-
pound (E)-4 was treated with a catalytic amount of
powdered sodium hydroxide in dry toluene at the reflux
temperature, to give the acetylene derivative (E)-5 in
By crystallization in hexane was purely isolated the
(E,E) isomer (74%; H-NMR, 6.65 and 6.45 ppm as
doublets, J=16.16 Hz; IR, 958 cm ) while the (E,Z)
isomer remains pure in the hexane solution (24%, H-
NMR, 6.79 and 6.58 ppm as doublets, J=16.17 Hz;
and 6.29 and 6.23 ppm as doublets, J=11.74 Hz; IR,
1
−
1
1
−
1
959 and 855 cm ).
1
practically quantitative yield ( H-NMR, 3.14, s; IR,
−
1
+
3
278 cm ; MS, 384 ([M ], 99%).
2.7. (E,Z)“(E,E) Isomerization of 1,1%-bis-[i-(p-
iodophenyl)ethenyl)ferrocene (7)
2.5. Synthesis of (E)-1-{i-[4-(i-(1%-formylferrocenyl)-
ethenyl)-phenylethynyl]-phenyl]-ethenyl}-1%-
formylferrocene ((E)-6)
Chemical isomerization of the E,Z isomer of 7 was
carried out in hexane by sunlight exposure, with iodine
in catalytic amounts, and after 5 days the transforma-
tion was quantitative (Scheme 4).
Compound (E)-2 was submitted to cross-coupling
with the acetylene derivative (E)-5 in presence of
dichlorobis(triphenylphosphine) palladium and cuprous
iodide, in freshly distilled triethylamine, under argon
atmosphere, giving a mixture of the 1%,1%-diacetal
derivative and the deprotected 1%,1%-diformyl derivative
2.8. Synthesis of (E,E)-1,1%-bis-[i-(p-iodophenyl)-
ethenyl)ferrocene (7) from 1,1%-diformylferrocene
The synthesis of (E,E)-1,1%-bis-[b-(p-iodophenyl)-
ethenyl)ferrocene (7) was now undertaken in one pot
from the Wittig reaction between 1,1%-diformylferrocene
and the p-iodobenzyltriphenylphosphonium ylide [16a].
After column chromatography a mixture of the E,E,
Z,E and Z,Z isomers were obtained in good yield
(62%). The E,E isomer was purely isolated (25%) from
(
E)-6 (Scheme 3). Thus, the mixture was completely
hydrolyzed and compound (E)-6 was purely isolated.
1
13
−1
(
CHO: H-NMR, 9.91; C, 193.6 ppm; IR, 1685 cm
;
+
ms, 654 ([M ], 100%).
2.6. Synthesis of (E,E)-1,1%-bis-[i-(p-iodophenyl)-
ethenyl)ferrocene (7) from (E)-3
a
concentrated solution of the isomers in di-
chloromethane and careful addition of hexane at room
temperature, while the mixture of Z,E and Z,Z isomers
were purely separated by silica gel column chromatog-
The acetal group in compound (E)-2 was hydrolyzed
completely with acetic acid (30%) to the formyl deriva-
tive (E)-3, which was transformed to the conjugate
1
raphy (26 and 11%, respectively). The Z,Z isomer [ H-
1
,1%-bis-[b-(p-iodophenyl)ethenyl)ferrocene by Wittig
NMR, 6.36 and 6.21 ppm, as doublets, J=11.83 Hz;
IR, 853 cm ; MS, 642 ([M ], 78%)] was obviously
never isolated starting from (E)-3.
−
1
+
reaction with the p-iodobenzyltriphenylphosphonium
ylid [14a]. Two stereoisomers of 7 were isolated, the

J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
233
2
1
.9. (Z,Z)/(E,Z)“(E,E) Isomerization of
,1%-bis-[i-(p-iodophenyl)ethenyl]ferrocene (7)
Compound (E,E)-9 was treated with a catalytic
amount of powdered sodium hydroxide in dry toluene
at the reflux temperature, to give the corresponding
1,1%-diacetylene derivative (E,E)-10 in practically quan-
The geometry of the (E,E) isomer exhibits better
1
electrical and optical properties and, it was necessary to
planify a method for the preparation of the (E,E) by
conversion of the (E,Z) and (Z,Z) isomers taking in
account the more favourable thermodynamic stability.
Chemical isomerization was carried out by sunlight
exposure of the (E,Z)/(Z,Z) (8:3) mixture in hexane
with iodine in catalytic amounts during 5 days in a
quantitative transformation (Scheme 4). The kinetic of
the isomerization for (E,Z) is faster than for the (Z,Z)
isomer. The time of complete isomerization increases
with the amount of sample for the same concentration,
probably due to a minor efficiency in the sunbeams
absorption process.
titative yield ( H-NMR, 6.73 and 6.55 ppm as doublets,
−
1
J=16.17; IR, 960 cm
.
2.11. Synthesis of biphenyl oligomer deri6ati6es from
(E,E)-7
The monosubstituted p-iodophenylethenylferrocene
gives the biphenyl derivative by oxidative homocou-
pling with zero-valent nickel complexes but in low yield
(
30%) [14a]. In this way, the analysis of the biphenyla-
tion of compound (E,E)-7 would give a controlled
oligomeric reaction.
The homocoupling reaction of (E,E)-7 was carried
out with zero-valent tris(triphenylphosphine) nickel,
prepared in situ from dichloro bis(triphenylphosphine
nickel and powder zinc in tetrahydrofuran. However, in
contrast with the monosubstituted derivative, the disub-
stituted compound (E,E)-7 was completely transformed
giving a mixture of the oligomers.
A precipitate was obtained from a dichloromethane
solution by careful addition of diethyl ether. This was
analyzed by a molecular mass characterization tech-
nique (MALDI) showing the presence of the oligomers,
intermolecular dimer and trimer mainly and tetramer
and the intramolecular dimer-box, which from the in-
tensity of the spectrum are in 75:55:10:6 molar ratio,
respectively (Scheme 5).
2.10. Synthesis of (E,E)-1,1%-[i-(4-ethynylphenyl)-
ethenyl]ferrocene (10)
The catalytic cross-coupling reaction of the 1,1%-di-(p-
iodophenyl) derivative (E,E)-7 to prepare the corre-
sponding ethynyl derivative, permits the extension of
the molecular conjugation through a terminal triple
bond (Scheme 4).
Thus, cross-coupling of compound (E,E)-7 with 2-
methyl-but-3-yn-2-ol was carried out in presence of
dichlorobis(triphenylphosphine) palladium and cuprous
iodide in triethylamine, under argon atmosphere. For
two equivalents of the propargylic alcohol derivative, a
mixture of (E,E)-1-{b-[4-(3-hydroxy-3-methyl-but-1-
ynyl)-phenyl]-ethenyl}-1%-[b-(p-iodophenyl)-ethenyl]-
ferrocene ((E,E)-8) and (E,E)-1,1%-bis-{b-[4-(3-hydroxy-
A new precipitate was separated from a hexane–
ethyl acetate solution and it was also analyzed giving a
mixture with the dimer-box as the main product.
3-methyl-but-1-ynyl)-phenyl]-ethenyl}-ferrocene ((E,E)-
9) was obtained, in a 4:3 molar ratio, respectively.
However, when the reaction was carried out with three
equivalents of the propargylic alcohol derivative, only
product (E,E)-9 was obtained, in practically quantita-
tive yield.
3. Experimental
Melting points were determined with a Reichert hot-
stage microscope and are uncorrected. IR spectra were
Scheme 4. (i) p-Iodobenzyltriphenylphosphonium ylide; (ii) I , sunlight; (iii) PdCl (PPh ) , Cu I , NEt ; (iv) NaOH, toluene, D.
2
2
3 2
2 2
3

234
J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
Scheme 5. NiCl (PPh ) , Zn, THF.
2
3 2
1
3
recorded using a Perkin–Elmer 681 spectrophotometer.
H-NMR (200 MHz) and C-NMR (50 MHz) spectra
3.97(m, 2H, CH(OCH ) ). C-NMR (CDCl ): 193.8
2 2 3
1
13
(CHO); 101.7 (–CH(OCH ) ); 85.3 (Cp); 78.8 (Cp);
2 2
were recorded with a Bruker WM-200-SY spectrome-
72.8 (Cp); 69.4 (Cp); 68.8 (Cp); 68.8 (Cp); 67.3 (Cp);
ter; chemical shifts are given in the l scale, using Me Si
64.4 (–CH (OCH ) ). IR (film): 1681 (CHO); 1095
4
2 2
as internal reference. Mass spectra were recorded using
a Hewlett–Packard SP85 spectrometer. Elemental
analyses were performed with a LECO CHN-900.
(C–O–C); 1027 (ferrocene).
Anal. Found: C, 58.53; H, 5.15. C H O Fe. Calc.:
C, 58.77; H, 4.93%.
14
14
3
3
.1. Synthesis of (E)-1%-[2-(1,3-dioxolan)]-1-
3.1.2. Diacetal
1
formylferrocene (1)
H-NMR (CDCl ): 5.75 (s, 2H, –CH(OCH ) ); 4.33
3 2 2
(
s, 4H, Cp); 4.20 (s, 4H, Cp); 4.00 (m, 4H,
13
In a Dean–Stark with a graduate side tube, contain-
CH(OCH ) ); 3.90 (m, 4H, CH(OCH ) ). C-NMR
2 2 2 2
ing MgSO (2.0 g), a solution of 1,1%-diformylferrocene
(CDCl ): 102.5 (–CH(OCH ) ); 85.0 (Cp); 69.1 (Cp);
3 2 2
4
(
1 g, 4.13 mmol) [15] was introduced in dry diethyl
68.2 (Cp); 65.0 (2C, –CH(OCH ) ); IR (KBr): 1890
2 2
ether (100 ml), ethylenglycol (4.62 ml, 82.6 mmol) and
a little amount of p-toluensulfonic acic. The mixture
was warmed at reflux temperature with stirring and
after 30 min the diethyl ether was removed giving a red
oil which was washed with an aqueous solution of
(CH ); 1494 (CH ); 1081 (C–O–C); 1025 (ferrocene);
819 (ferrocene).
2
2
Anal. Found: C, 58.03; H, 5.54. C H O Fe. Calc.:
16
18
4
C, 58.21; H, 5.50%.
ammonium chloride with KHCO and extracted with
3.2. Synthesis of (E)-1%-[2-(1,3-dioxolan)]-1-[i-(p-
iodophenyl)ethenyl]ferrocene (2)
3
CH Cl . The organic layer was separated and dried
2
2
with MgSO , and solvent was evaporated to give an oil
4
which was purified by column chromatography using
ethyl acetate:hexane (4:1) as eluent, (and 5% of triethy-
lamine for the column preparation) giving 1 (0.708 g,
To a suspension of p-iodobenzyltriphenylphospho-
nium bromide [16a], (1.53 g, 3.2 mmol) in dry toluene
(50 ml) at 0 °C, potassium tert-butoxide (0.54 g, 4.8
mmol) was added and stirred for 30 min. This solution
was then added slowly to a solution of the formylfer-
rocene derivative 1 (0.61 g, 2.13 mmol) in dry toluene
60%) as a red oil; the diacetal derivative was also
isolated (0.277 g, 20%) as a red brown solid, m.p.
1
3
–
03–104 °C.
(
20 ml) at 0 °C under argon atmosphere, stirring for 22
.1.1. Compound 1
h at room temperature (r.t.). After solvent evaporation
under reduced pressure, the residual red solid was
solved in dichloromethane and washed with an aqueous
solution of ammonium chloride and potassium carbon-
1
H-NMR (CDCl ): 9.95 (s, 1H, CHO); 5,61 (s, 1H,
3
CH(OCH ) ); 4.81 (s, 2H, Cp); 4.62 (s, 2H, Cp); 4.41
2
2
(
s, 2H, Cp); 4.27(s, 2H, Cp); 4.01 (m, 2H, CH(OCH ) );
2 2

J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
235
ate. The organic layer was dried on MgSO , filtered and
molar ratio, respectively (by NMR). Finally both prod-
ucts were purely isolated by pressured silica gel column
chromatography using ethyl acetate:hexane (4:1) (a 5%
of triethylamine was added for the column preparation)
to give (E)-2 as a red oil (105 mg, 26%) and (E)-3 pure
as an orange red crystalline solid, m.p. 135–136 °C,
(260 mg, 72%).
4
solvent removed under reduced pressure. The residual
solid was purified by column chromatography using
hexane:ethyl acetate (4:1) (a 5% of triethylamine was
added for the column preparation). A mixture of the
E/Z isomers of 2 was obtained (0.89 g, 87%) molar
ratio (2:1, by NMR). By crystallization from hexane,
(
E)-2 (0.62 g, 61%) was isolated, m.p. 118–119 °C,
while (Z)-2, (0.26 g, 25%) remained in solution, and
was isolated as an orange oil.
3.3.1. Compound (E)-3
1
H-NMR (CDCl ): 9.85 (s, 1H, CHO); 7.62 (d, 2H,
3
J=8.09 Hz, H-3§ and H-5§); 7.14 (d, 2H, J=8.09 Hz,
H-2§ and H-6§);6.73 (d, 1H, J=16.17,H-2¦); 6.60 (d,
1H, J=16.17, H-1¦); 4.72 (s, 2H, Cp);4.52 (s, 4H, Cp);
3
.2.1. Compound (E)-2
1
H-NMR (CDCl ): 7.63 (d, 2H, J=8.4, H-3§ and
3
13
H-5§); 7.17 (d, 2H, J=8.4, H-2§ and H-6§); 6.88 (d,
4.38 (s, 2H, Cp). C-NMR (CDCl ): 193.6 (CHO);
3
1
H, J=16.2, H-2¦); 6.61 (d, 1H, J=16.2, H-1¦); 5.67
137.7 (C-3§ and C-5§); 136.7 (C-1§); 127.7 (C-2§ and
C-6§); 126.8 (C-2¦); 125.9 (C-1¦); 93.3 (C-4§); 84.8
(Cp); 79.7 (Cp); 74.2 (Cp); 70.5 (Cp); 68.2 (2C, Cp); IR
(KBr): 1681 (CHO); 1632 (CꢀC); 1002 (ferrocene); 961
(ꢀC–H, E); 806 (p-sust. ArH); 479 (C–I); MS: 442
(
s, 1H, -CH(OCH ) ); 4.48 (s, 2H, Cp); 4.33 (s, 2H, Cp)
2
2
4
.28 (s, 2H, Cp); 4.14 (s, 2H, Cp); 4.09 (m, 2H,
13
CH(OCH ) ); 3.90 (m, 2H, CH(OCH ) ). C-NMR
2
2
2 2
(
(
(
(
(
9
CDCl ):137.6 (C-3§ and C-5§); 137.4 (C-1§); 127.6
C-2¦); 127.5 (C-2§ and C-6§); 125.0 (C-1¦); 102.4
CH(OCH ) ); 91.5 (C-4§); 85.0 (Cp); 83.4 (Cp); 70.0
Cp); 69.8 (Cp); 67.8 (Cp); 67.7 (Cp); 65.2
CH(OCH ) ). IR (KBr): 1631 (CꢀC); 1084 (C–O–C);
64 (ꢀC–H isomer E); 805 (p-subst. ArH); 819 (fer-
3
+
([M ], 96%), 287 (16), 165 (100), 121 (38).
2
2
3.4. Synthesis of (E)-1-[i-(4-ethynylphenyl)-ethenyl]-1%-
[2-(1,3-dioxolan)]ferrocene ((E)-5)
2
2
+
rocene); 489 (C–I). MS: 486 ([M ], 66%), 442 (10), 287
14), 165 (100), 121 (40).
3.4.1. (a) (E)-1-{i-[4-(3-hydroxy-3-methyl-but-1-
ynyl)phenyl]-ethenyl}-1%-[2-(1,3-dioxolan)]ferrocene
(
(
(E)-4)
In a three-necked round-bottom flask, previously
3
.2.2. Compound (Z)-(2)
1
H-NMR (CDCl ): 7.59 (d, 2H, J=8.2, H-3§y H-
flamed and under argon atmosphere, a mixture of
freshly distilled triethylamine (10 ml) were placed
purged with argon, and (E)-1%-[2-(1,3-dioxolan)]-1-[b-
(p-iodophenyl)ethenyl]ferrocene, (E)-2 (200 mg, 0.41
mmol) and 2-methyl-but-3-yn-2-ol (59 ml, 0.62 mmol).
The mixture was stirred at r.t. and then dichlorobist-
riphenylphosphine palladium(II), 5.48 mg (0.0078
mmol) and a little amount of cuprous iodide in triethy-
lamine (10 ml), were added in this order, and stirred for
18 h. Then, solvent was removed under reduced pres-
sure and the residual solid was solved in
dichloromethane (25 ml) and washed with a solution of
3
5
§); 7.06 (d, 2H, J=8.2, H-2§ and H-6§); 6.36 (d, 1H,
J=12.3, H-2¦); 6.33 (d, 1H, J=12.3, H-1¦); 5.68 (s,1H,
–
CH(OCH ) ); 4.22 (s, 2H, Cp); 4.21 (s, 2H, Cp); 4.18
2 2
(
s, 2H, Cp); 4.11 (s, 2H, Cp); 4.01 (m, 2H,
13
CH(OCH ) ); 3.93 (m, 2H, CH(OCH ) ). C-NMR
2
2
2 2
(
(
(
(
(
8
CDCl ): 137.5 (C–1§); 137.0 (C-3§ and C-5§); 130.6
C-2§ and C-6§); 128.6 (C-2¦); 126.1 (C-1¦); 102.4
CH(OCH ) ); 91.7 (C-4§); 84.9 Cp); 81.6 (Cp); 70.1
3
2
2
Cp); 69.8 (Cp); 69.5(Cp); 67.9 (Cp); 65.2
CH(OCH ) ). IR (KBr): 1632 (CꢀC); 1005 (ferrocene);
2
2
63 (ꢀC–H, isomer Z); 826 (p-subst. ArH); 807 (fer-
+
rocene). MS: 486 ([M ], 47%), 442 (50), 287 (16), 165
100), 121 (38).
NH Cl (500 mg) and NaCN (25 mg), in water (25 ml)
4
(
and stirred for 2 h. The organic layer was dried on
Na SO , and after filtration solvent was removed to
2
4
3
.3. (Z)“(E) Isomerization of 1%-[2-(1,3-dioxolan)]-1-
give a residual solid, which was purified by pressured
silica gel column chromatography using hexane:ethyl
acetate (3:1) (a 5% of triethylamine was added for the
column preparation). Compound (E-4) was isolated as
an orange solid, m.p. 119–120 °C, (170 mg, 94%).
[i-(p-iodophenyl)ethenyl]ferrocene
To a solution of (Z)-2 isomer (400 mg, 0.82 mmol) in
hexane (150 ml) a crystal of iodine was added. The
mixture was exposed to the sunlight and stirred for 4
days at r.t. (monitoring by thin layer chromatography).
Later the solvent was removed under reduced pressure
and the residual solid was solved in dichloromethane
and treated with an aqueous solution of sodium thio-
sulfate. The organic layer was dried on MgSO , filtered
and solvent removed under reduced pressure giving a
mixture of (E)-2 and their aldehyde (E)-3 in a 1:3
3.4.2. Compound (E)-4
1
H-NMR (CDCl ): 7.36 (s, 4H, H-2§, H-3§, H-6§
3
and H-5§); 6.90 (d, 1H, J=16.17, H-2¦); 6.71 (d, 1H,
J=16.17, H-1¦); 5.66 (s,1H, –CH(OCH ) ); 4.49 (s,
2
2
2H, Cp); 4.34 (s, 2H, Cp); 4.29 (s, 2H, Cp); 4.15 (s, 2H,
Cp); 4.02 (m, 2H, CH(OCH ) ); 3.89 (m, 2H,
4
2
2
1
3
CH(OCH ) ); 1.63 (s, 6H, 2 CH ). C-NMR (CDCl3):
2 2 3

236
J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
1
37.8 (C-1§); 131.9 (C-3§ and C-5§); 127.7 (C-2¦); 125.5
After 16 h, solvent was removed under reduced pres-
sure and the solid residue was washed with a solution
(
(
8
C-2§, C-6§ and C-1¦); 120.7 (C-4§); 102.4
(CH(OCH ) ); 94.2 (CꢁC–C(CH ) OH)); 85.0 (Cp);
of NH Cl (0.5 g) and NaCN (25 mg) in water (30 ml)
2
2
3 2
4
3.5 (Cp); 82.3 (CꢁC–C(CH ) OH)); 70.0 (Cp); 69.6
and stirred for 2 h. The mixture was extracted with
dichloromethane (25 ml) and the red organic layer was
dried on Na SO , filtered and solvent removed to give a
3
2
(
6
Cp); 67.8 (Cp); 67.7 (Cp); 65.6 (CꢁC–C(CH ) OH));
3
2
5.2 (CH(OCH ) ); 31.4 (CꢁC–C(CH ) OH)). IR
2
2
3 2
2
4
(
(
KBr): 3452 (OH); 1630 (CꢀC); 1084 (C–O–C); 958
ꢀC–H); 859 (p-subst. ArH); 815 (ferrocene).
residual solid, which was purified by silica gel column
chromatography using toluene:ethyl acetate 20:1 (a 5%
of triethylamine was added for the column prepara-
tion). The treatment of the mixture with acetic acid (25
ml, 50%), neutralisation with solid Na CO , and extrac-
Anal. Found: C, 70.43; H, 5.89. C H O Fe. Calc.:
2
6
26
3
C, 70.60; H, 5.92%.
2
3
tion with dichloromethane (25 ml) gave (E,E)-6 as a
crystalline red solid, m.p. \240 °C, (104 mg, 63%).
3
.4.3. (b) (E)-1-[i-(4-ethynylphenyl)-ethenyl]-1%-[2-(1,3-
dioxolan)]ferrocene ((E)-5)
In a three-necked round-bottom flask, previously
flamed and under argon atmosphere, (E)-4 (200 mg,
3
.5.1. Compound (E,E)-6
1
0.45 mmoles) in dry toluene (25 ml) were placed and
H-NMR (CDCl ): 9.91 (s, 2H, CHO); 7.50 (d, 4H,
3
V
V
then finally powdered sodium hydroxide (12 mg). The
mixture was warmed at reflux temperature for 15 h and
then filtered, and solvent removed under reduced pres-
sure. The residual solid was purified by pressured silica
gel column chromatography using hexane:ethyl acetate
J=8.61, H-3§, H-3 , H-5§, H-5 ); 7.41 (4H, J=8.61,
V
V
H-2§, H-2 , H-6§, H-6 ); 6.81 (d, 2H, J=16.43, H-2¦
IV
IV
and H-2 ); 6.70 (d, 2H, J= 16.43, H-1¦ and H-1 );
4
.76 (s, 4H, Cp); 4.57 (s, 8H, Cp); 4.40 (s, 4H, Cp).
13
C-NMR (CDCl ): 193.6 (CHO); 137.2 (C-1§); 132.0
3
(
4:1) (a 5% of triethylamine was added for the column
(
(
(
(
(
C-3§ and C-5§); 127.4 (C-2¦); 126.0 (C-1¦); 125.9
C-2§, C-6§);122.0 (C-4§); 90.5 (CꢁC); 85.0 (Cp); 79.8
Cp); 74.4 (Cp); 70.7 (Cp); 68.3 (Cp). MS (70 eV): 654
[M ], 100%); 561 (13%); 411(13%). IR (KBr): 1685
CHO); 1628 (CꢀC); 970 (ꢀCH, E); 827 (p-subst. ArH).
preparation). Compound (E)-5 was isolated as a red
solid, m.p. 94–95 °C, 168 mg, 96%).
+
3
.4.4. Compound (E)-5
1
Anal. Found: C, 76.93; H, 4.92.C H Fe . Calc.: C,
H-NMR (CDCl ): 7.44 (d, 2H, J=8.49, H-3§ and
40 30
2
3
7
7.19; H, 4.86%.
H-5§);7.36 (2H, J=8.49, H-2§ and H-6§); 6.90 (d, 1H,
J=16.17, H-2¦); 6.35 (d, 1H, J=16.17, H-1¦); 5.65
(
s,1H, –CH(OCH ) ); 4.49 (s, 2H, Cp); 4.33 (s, 2H,
2 2
3.6. Synthesis of (E,E)-1,1%-bis-[i-(p-iodophenyl)-
Cp); 4.29 (s, 2H, Cp); 4.14 (s, 2H, Cp); 4.00 (m, 2H,
CH(OCH ) ); 3.86 (m, 2H, CH(OCH ) ); 3.14 (s, 1H,
ethenyl)ferrocene ((E,E)-7) from (E)-3
2
2
2 2
1
3
(
3
(
CꢁC–H). C-NMR (CDCl ): 138.3 (C-1§); 132.7 (C-
3
In a three-necked round-bottom flask, previously
flamed and under argon atmosphere, p-iodobenzyl-
triphenylphosphonium bromide [16a] (0.481 g, 1.01
mmol) in dry toluene (15 ml) was placed at 0 °C. A
solution of potassium tert-butoxide (0.161 g, 0.67
mmol) in dry toluene (10 ml) was added and stirred for
§ and C-5§); 128.1 (C-2¦); 125.4 (C-2§, C-6§);125.3
C-1¦); 119.9 (C-4§); 102.3 ((CH(OCH ) ); 85.0 (CꢁC–
2
2
H); 83.9 (CꢁC–H); 83.4 (Cp); 75.5 (Cp); 70.0 (Cp); 69.5
(
Cp); 67.7 (Cp); 65.1 (CH(OCH ) ). IR (KBr): 3278
2 2
(
8
(
CꢁC–H); 1633 (CꢀC); 1088 (C–O–C); 950 (ꢀC–H, E);
+
24 (p-subst. ArH). MS: 384 ([M ], 99%), 340 (6), 312
3
0 min and then at 0 °C, under argon atmosphere, a
solution of (E)-3 (0.296 g, 0.67 mmol) in dry toluene
10 ml) was added slowly. The mixture was stirred at
20), 247 (42), 189 (100).
(
3
.5. Synthesis of (E)-1-{i-[4-(i-(1%-formylferrocenyl)-
r.t. for 15 h and then, solvent was removed under
reduced pressure. The residual red solid was solved in
dichloromethane, washed with an aqueous solution of
ammonium chloride and the organic layer dried on
ethenyl)-phenylethynyl]-phenyl]-ethenyl}-1%-
formylferrocene ((E,E)-6)
In a three-necked round-bottom flask, previously
flamed and under argon atmosphere, a mixture of
freshly distilled diethylamine (7 ml) were placed purged
with argon, and (E)-5 (95 mg, 0.25 mmol) and (E)-2
MgSO . After filtration the solvent was removed under
4
reduced pressure to give a residual solid, which was
purified by silica gel column chromatography using
hexane:ethyl acetate (4:1). A mixture of E,E and E,Z
isomers of 7 (3:1 by NMR) was obtained (0.425 g,
99%). By crystallization from hexane (E,E)-7 (0.318 g,
74%) was purely isolated as a red solid, m.p. 166–
167 °C while that remained in the hexane solution,
(E,Z)-7, (0.14 g, 24%) was isolated as an orange–red
solid, m.p. 89–90 °C.
(
122 mg, 0.25 mmol) in freshly distilled triethylamine
(
30 ml) purged with argon. The mixture was stirred
at r.t. and then dichlorobistriphenylphosphine pal-
ladium(II) (1.25 mg, 0.0017 mmol) and cuprous iodide
(
1.0 mg) were added in this order. The mixture was
stirred at room temperature giving a red precipitate.

J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
237
3
.6.1. Compound (EE)-7
The mixture was stirred at r.t. for 36 h and after solvent
evaporation under reduced pressure, the residual red
solid was solved in dichloromethane, washed with an
aqueous solution of ammonium chloride and the or-
1
V
H-NMR (CDCl ): 7.5 (d, 4H, J=8.39, H-3§,H-3 ,
3
V
V
H-5§, H-5 ); 6.94 (d, 4H, J=8.39, H-2§, H-2 , H-6§,
H-6 ); 6.65 (d, 2H, J=16.16, H-2¦ and H-2 ); 6.45 (d,
V
IV
IV
2
H, J=16.16, H-1¦ and H-1 ); 4.41 (s, 4H, Cp); 4.26
ganic layer dried on MgSO . Later the mixture was
4
1
3
V
(
s, 4H, Cp). C-NMR (CDCl ): 137.5 (C-3§, C-3 ,
filtered and solvent removed under reduced pressure to
give a residual solid, which was purified by column
chromatography using hexane:ethyl acetate (4:1). A
mixture of E,E, E,Z and Z,Z isomers of 7 were ob-
tained as a red solid (1.3 g, 62%) in 41:43:16 molar ratio
(by NMR). To a concentrate solution of the mixture of
7 in CH Cl , hexane was slowly dropped and the E,E
3
V
V
C-5§ and C-5 ); 137.0 (C-1§ and C-1 ); 127.3 (C-2§,
V
V
IV
C-2 , C-6§ and C-6 ); 126.7(C-2¦ and C-2 ); 125.4
IV
V
(
C-1¦ and C-1 ); 91.5 (C-4§ and C-4 ); 83.9 (C-1 and
C-1%); 70.0 (Cp); 67.9 (Cp). IR (KBr): 1626 (CꢀC); 1000
(
(
(
ferrocene); 958 (ꢀC–H, E); 800 (p-subst. ArH); 482
C–I). MS: 642 ([M ], 75%), 349 (15), 222 (14), 165
+
2
2
100).
pure isomer precipitated as a red solid (0.53 g, 25%),
m.p. 166–167 °C. The mixture of (E,Z) and (Z,Z)
isomers obtained from evaporation of the hexane solu-
tion, were purely isolated by silica gel column chro-
matography using hexane:dichloromethane (10:1) as the
eluent; the (E,Z)-7 isomer was an orange solid (0.55 g,
26%), m.p. 88–90 °C and the (Z,Z)-7 isomer was a
dark red solid (0.21 g, 10%), m.p. 72–73 °C.
3.6.2. Compound (E,Z)-7
1
V
H-NMR (CDCl ): 7.68 (d, 2H, J=8.21, H-3 and
3
V
H-5 ); 7.55 (d, 2H, J=8.21, H-3§ and H-5§); 7.17 (d,
V
V
2
H, J=8.21, H-2 , H-6 ); 7.00 (d, 2H, J=8.21, H-2§,
H-6§); 6.79(d, 1H, J=16.17, H-2¦); 6.58 (d, 1H, J=
1
IV
6.17, H-1¦); 6.29 (d, 1H, J=11.74, H-2 ); 6.23 (d,
IV
1H, J=11.74, H-1 ); 4.38 (s, 2H, Cp); 4.25 (s, 2H,
1
3
Cp); 4.16 (s, 4H, Cp). C-NMR (CDCl ): 137.6 (C-3§,
3
3.8.1. Compound (Z,Z)-7
V
V
C-5§); 137.4 (C-1 ); 137.2 (C-1§); 137.0 (C-3 and
1
V
H-NMR (CDCl ): 7.59 (d, 4H, J=8.6, H-3§, H-3 ,
3
V
V
V
IV
C-5 ); 130.4 (C-2 and C-6 ); 128.5 (C-2 ); 127.4
V
V
H-5§, H-5 ); 7.06 (d, 4H, J=8.6, H-2§, H-2 , H-6§,
IV
(
9
C-2§, C-6§); 127.3 (C-2¦); 126.4 (C-1 ); 125.2 (C-1¦);
V
IV
H-6 ); 6.36 (d, 2H, J=11.83, H-2¦ and H-2 ); 6.21 (d,
V
1.8 (C-4 ); 91.6 (C-4§); 83.5 (C-1); 81.6 (C-1%); 70.5
IV
2
H, J=11.83, H-1¦ and H-1 ); 4.12 (s, 4H, Cp); 4.07
(
(
8
Cp); 70.3 (Cp); 69.8 (Cp); 68.1 (Cp). IR (KBr): 1629
CꢀC); 1001 (ferrocene); 959 (ꢀCH, E); 855 (ꢀC–H, Z);
1
3
V
(
1
s, 4H, Cp); C-NMR (CDCl ): 137.4 (C-1§ and C-1 );
3
V
V
V
37.1 (C-3§, C-3 , C-5§ and C-5 ); 130.6 (C-2§, C-2 ,
V IV
+
03 (p-subst. ArH); 475 (C–I). MS: 642 ([M ], 89%),
49 (17), 222 (14), 165 (100).
C-6§ and C-6 ); 128.3 (C-2¦ and C-2 ); 126.1 (C-1¦
3
IV
V
and C-1 ); 91.8 (C-4§ and C-4 ); 81.6 (C-1 and C-1%);
7
0.5 (Cp); 69.9 (Cp). IR (KBr): 1625 (CꢀC); 1005
3.7. (E,Z)“(E,E) Isomerization 1,1%-bis-[i-(p-
(
(
(
ferrocene); 853 (ꢀC–H, Z); 800 (p-subst. ArH); 488
iodophenyl)ethenyl)ferrocene (7)
+
C–I). MS: 642 ([M ], 92%), 349 (18), 222 (15), 165
100).
To a solution of (E,Z)-7 isomer (0.23 g, 0.36 mmol)
in hexane (100 ml) a crystal of iodine was added. The
mixture was exposed to the sunlight and stirred for 10
days at r.t. (monitoring by thin layer chromatography).
Later the solvent was removed under reduced pressure
and the residual solid was solved in dichloromethane
and treated with an aqueous solution of sodium thio-
3
1
.9. (Z,Z)/(E,Z)“(E,E) Isomerization of
,1%-bis-[i-(p-iodophenyl)ethenyl]ferrocene (7)
To a solution of (E,Z)-7 and (Z,Z)-7 (1.0 g, 1.56
mmol) in hexane (425 ml) a crystal of iodine was added.
The mixture was exposed to the sunlight and stirred for
sulfate. The organic layer was dried on MgSO , filtered
4
1
0 days at r.t. (monitoring by thin layer chromatogra-
and solvent removed under reduced pressure giving
phy). Later the solvent was removed under reduced
pressure and the residual solid was solved in
dichloromethane and treated with an aqueous solution
of sodium thiosulfate. The organic layer was dried on
(
E,E)-7 in quantitative yield, m.p. 166–167 °C.
3.8. Synthesis of (E,E)-1,1%-bis-[i-(p-iodophenyl)-
ethenyl)ferrocene (7) from 1,1%-diformylferrocene
MgSO , filtered and solvent removed under reduced
4
pressure giving (E,E)-7 in quantitative yield, m.p. 166–
In a three-necked round-bottom flask, previously
flamed and under argon atmosphere, p-iodobenzylt-
riphenylphosphonium bromide (5.42 g, 11.34 mmol)
1
67 °C.
3.10. Synthesis of (E,E)-1,1%-[i-(4-ethynylphenyl)-
[14a] in dry toluene (25 ml) was placed at 0 °C. Potas-
ethenyl]ferrocene (10)
sium tert-butoxide (1.91 g, 17.01 mmol) was added and
stirred for 40 min and then at 0 °C, under argon
atmosphere, a solution of 1,1%-diformylferrocene (0.78
g, 3.24 mmol) in dry toluene (20 ml) was slowly added.
3.10.1. (a) (E)-1-{i-[4-(3-hydroxy-3-methyl-but-1-
ynyl)phenyl]-ethenyl}-1%-[2-(1,3-dioxolan)]ferrocene (9)

238
J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
In a three-necked round-bottom flask, previously
(KBr): 3283 (OH); 1630 (CꢀC); 962 (ꢀC–H, E); 926
(p-subst. ArH); 812 (ferrocene).
Anal. Found: C, 82.48; H, 6.82. C H Fe. Calc.: C,
flamed and under argon atmosphere, a mixture of
freshly distilled triethylamine (30 ml) purged with ar-
gon, and (E,E)-7 (0.2 g, 0.31 mmol) and 2-methyl-but-
36
34
82.75; H, 6.56%.
3-yn-2-ol (90 ml, 0.96 mmol) were placed. The mixture
was stirred at r.t. and then dichlorobistriphenylphos-
phine palladium (4.21 mg, 0.006 mmol) and a little
amount of cuprous iodide in triethylamine (10 ml), were
added in this order. After 14 h stirring at r.t., the
solvent was removed under reduced pressure and the
residual solid was solved in dichloromethane (20 ml)
3.10.4. (b) (E,E)-1,1%-[i-(4-ethynylphenyl)-
ethenyl]ferrocene (10)
In a three-necked round-bottom-flask, previously
flamed and under argon atmosphere, (E,E)-9 (0.163 g,
0.29 mmoles) in dry toluene (25 ml) and finally pow-
dered sodium hydroxide (10 mg) were placed. The
mixture was warmed at reflux temperature for 15 h, and
then filtered and solvent removed under reduced pres-
sure. The residual solid was washed with hexane, giving
(E,E)-10 as a red solid, m.p. 208–209 °C, 127 mg,
99%).
and washed with a solution of NH Cl (500 mg) and
4
NaCN (25 mg), in water (25 ml) and stirred for 2 h.
The organic layer was dried on Na SO , and after
2
4
filtration solvent was removed to give a residual solid,
which was purified by pressurized silica gel column
chromatography using hexane:ethyl acetate (3:1). Com-
pound (E,E)-8 was isolated as a red solid (173 mg,
3.10.5. Compound (E,E)-10
1
99%), m.p. 189–190 °C.
H-NMR (CDCl ): 7.33 (d, 4H, J=8.09, H-3§, H-
3
V
V
V
For an equimolar mixture of (E,E)-7/propargylic al-
3 , H-5§, H-5 );7.20 (d, 4H, J=8.09, H-2§, H-2 ,
V IV
cohol, (E,E)-9 was obtained in low yield (6 mg, 7%)
together the monocross-coupling product (E,E)-8, as a
red solid (17.3 mg, 19%), m.p. 172–174 °C.
H-6§, H-6 ); 6.73 (d, 2H, J=16.17, H-2¦ and H-2 );
IV
6.55 (d, 2H, J=16.17, H-1¦ and H-1 ); 4.42 (s, 4H,
13
Cp); 4.28 (s, 4H, Cp); 3.14 (s, 2H, ꢁC–H). C-NMR
V
V
(
CDCl ): 138.1 (C-1§ and C-1 ); 132.4 (C-3§, C-3 ,
3
V IV
3
.10.2. Compound (E,E)-8
C-5§ and C-5 ); 127.4 (C-2¦ and C-2 ); 125.7 (C-1¦
1
V
IV V V
H-NMR (CDCl ): 7.53 (d, 2H, J=8.6, H-3 , H-
and C-1 ); 125.4 (C-2§, C-2 , C-6§ and C-6 ); 120.0
3
V
V
5
);7.27 (d, 2H, J=8.6, H-3§, H-5§); 7.16 (d, 2H,
(C-4§ and C-4 ); 83.9 (ꢁC–H)); 83.8 (Cꢁ)); 77.5 (C-1
V
V
J=8.6, H-2§, H-6§); 6.96(d, 2H, J=8.6, H-2 , H-6 );
6
and C-1%); 70.2 (Cp); 68.2 (Cp). IR (KBr): 3276 (CꢁC–
H); 1630 (CꢀC); 960 (ꢀC–H); 859 (p-subst. ArH).
Anal. Found: C, 82.03; H, 5.50. C H Fe. Calc.: C,
.70 (d, 1H, J=16.13, HCꢀCH); 6.69 (d, 1H, J=16.13,
HCꢀCH); 6.55 (d, 1H, J=16.13, HCꢀCH); 6.49(d, 1H,
J=16.13, HCꢀCH); 4.46 (s, 4H, Cp); 4.31 (s, 4H, Cp);
30
22
81.91; H, 5.39%.
1
3
2
(
1
(
.06 (s, 1H, OH); 1.69 (s, 6H, 2 CH ). C-NMR
3
V
V
V
CDCl ): 138.1(C-5 and C-3 ); 137.7 (C-1§ and C-1 );
3.11. Biphenylation of (E,E)-1,1%-bis-[i-(p-iodophenyl)-
ethenyl)ferrocene (7) catalyzed by nickel zero6alent
complexes
3
V
V
32.5 (C-3§ and 5§); 127.9 (C-2 and C-6 ); 127.5
IV IV
C-2 ); 127.4 (C-2¦); 126.5 (C-1¦); 126.1 (C-1 ); 126.0
(
C-2¦ and C-6§); 121.3 (C-4§); 94.8 (CꢁC-
V
C(CH ) OH)); 91.1 (C-4 ); 84.6 (Cp); 84.5 (Cp); 83.1
In a round-bottom flask under argon atmosphere a
3
2
(
CꢁC–C(CH ) OH)); 70.7 (Cp); 68.6 (Cp); 66.4 (CꢁC–
solution of anhydrous NiCl (PPh ) (0.4 g, 0.61 mmol)
3
2
2
3 2
C(CH ) OH)); 32.2 (2CH ). IR (KBr): 3418 (OH); 1628
(
rocene); 799 (p-subst. ArH); 483 (C–I).
in anhydrous THF (17 ml), tetrabutyl ammonium io-
dide (0.227 g, 0.61 mmol) and Zn powder (40 mg, 0.61
mmol) was placed. The mixture solution was stirred at
r.t., changing from green to red in colour, and after 30
min a solution of (E,E)-7 (193 mg, 0.61 mmol) in
anhydrous THF (10 ml) was added. After 3 days all of
the starting compound 7 was transformed and then
dichloromethane (50 ml) was added to the mixture and
the nickel catalyst filtered and destroyed with a solution
of HCl (10%). The dichloromethane solution was
dropped with diethyl ether to give a red precipitate,
which was analyzed by molecular mass characterization
techniques (MALDI), giving a mixture of the dimer
3
2
3
CꢀC); 1002 (ferrocene); 956 (ꢀC–H, E); 812 (fer-
Anal. Found: C, 63.69; H, 4.82. C H FeI. Calc.: C,
3
1
27
6
3
3.94; H, 4.67%.
.10.3. Compound (E,E)-9
1
V
H-NMR (CDCl ): 7.21 (d, 4H, J=8.49, H-3§,H-3 ,
3
V
V
H-5§, H-5 ); 7.10 (d, 4H, J=8.49, H-2§, H-2 , H-6§,
V
IV
H-6 ); 6.64 (d, 2H, J=16.17, H-2¦ and H-2 ); 6.51 (d,
IV
2
H, J=16.17, H-1¦ and H-1 ); 4.42 (s, 4H, Cp); 4.27
(
s, 4H, Cp); 2.54 (s, 2H, OH); 1.63 (s, 6H, 2 CH ).
3
1
3
V
C-NMR (CDCl ): 137.4 (C-1§ and C-1 ); 131.8 (C-
3
V
V
IV
+
+
+
3
(
1
(
§,C-3 , C-5§ and C-5 ); 126.9 (C-2¦ and C-2 ); 125.9
([M ], 1030), trimer ([M ], 1418), tetramer ([M ],
IV
V
V
+
C-1¦ and C-1 ); 125.3 (C-2§, C-2 , C-6§ and C-6 );
1806), dimer-box ([M ], 776) which from the intensity
V
20.6 (C-4§ and C-4 ); 94.1 (CꢁC–C(CH ) OH)); 84.1
of the spectrum are in a 75:55:10:6 ratio, respectively. A
new precipitate was isolated from a solution of hex-
ane–ethyl acetate and it was also analyzed by MALDI
3
2
C-1 and C-1%); 82.4 (CꢁC–C(CH ) OH)); 69.9 (Cp);
3
2
6
7.9 (Cp); 65.6 (CꢁC–C(CH ) OH)); 31.5 (2CH ). IR
3
2
3

J.-G. Rodr ´ı guez, S. Pleite / Journal of Organometallic Chemistry 637–639 (2001) 230–239
239
+
[
5] S.R. Marder, D.W. Bruce, D. O’Hare (Eds.), Inorganic Materi-
als, Wiley, Chichester, 1992, p. 115 and references cited therein.
6] (a) Z. Yuan, G. Stringer, I.R. Jobe, D. Kreller, K. Scott, L.
Koch, N.J. Taylor, T.B. Marder, J. Organomet. Chem. 452
giving a mixture with the dimer-box ([M ], 776), as the
main product.
[
(
(
1993) 115;
b) K.L. Kott, D.A. Higgins, R.J. McMahon, R.C. Corn, J. Am.
Acknowledgements
Chem. Soc. 115 (1993) 5342;
c) N.J. Long, Angew. Chem. Int. Ed. Engl. 34 (1995) 21.
(
We are indebted to the CAYCIT of Spain for finan-
cial support (project no. PB97-0060).
[
[
7] (a) J.L. Oudar, D.S. Chemla, J. Chem. Phys. 66 (1977) 2664;
(b) B.F. Levine, C.C. Betea, J. Chem. Phys. 66 (1977) 1070.
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(
b) J.C. Calabrese, L.-T. Cheng, J.C. Green, S.R. Marder, W.
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