Synthesis, characterisation and properties of platinum(II) acetylide complexes of ferrocenylfluorene: Novel soluble donor-acceptor heterometallic materials

Article abstract of DOI:10.1039/a803168a

Two new bis(acetylide)-functionalised ferrocenylfluorene complexes, 9-ferrocenylmethylene-2,7-bis-(trimethylsilylethynyl)fluorene 1 and -2,7-bis(ethynyl)fluorene 2, have been prepared in good yield by condensation of ferrocenecarbaldehyde with 2,7-bis(trimethylsilylethynyl)fluorene and the subsequent desilylation of 1. Treatment of trans-[PtPh(Cl)(PEt₃)₂] with half an equivalent of 2 in CH₂Cl₂-NHPrⁱ₂, in the presence of CuI, at room temperature, gives the dimeric platinum(II) complex trans-[Ph(Et₃P)₂-Pt-C≡CRC≡C-Pt(PEt ₃)₂Ph] 3 (R = 9-ferrocenylmethylenefluorene-2,7-diyl) in 56% yield. Soluble polymeric trans-[{-Pt(PBuⁿ₃)₂-C≡CRC≡C-} _n] 4 has been obtained in good yield by the CuI-catalysed dehydrohalogenation of trans-[Pt(PBuⁿ₃)₂Cl₂] with 2 (1:1 molar ratio) in an amine solvent. Optical measurements on the thin films indicated that there is a significant reduction in the bandgap value for polymer 4 (2.1 eV) as compared to that of trans-[{-Pt(PBuⁿ₃)₂-C≡CRC≡C-} _n] 5 (R = fluorene-2,7-diyl) (2.9 eV) without the ferrocenyl moiety, featuring the importance of donor-acceptor interaction in such conjugated systems. All the new compounds have been characterised by analytical, spectroscopic and electrochemical methods, and the single-crystal structures of 2, 3 and 5 have been established.

Full text of DOI:10.1039/a803168a

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Synthesis, characterisation and properties of platinum(II) acetylide
complexes of ferrocenylfluorene: novel soluble donor–acceptor
heterometallic materials‡
Wai-Yeung Wong,*,†,a Wai-Kwok Wonga and Paul R. Raithbyb
a Department of Chemistry, Hong Kong Baptist University, Waterloo Road, Kowloon Tong,
Hong Kong
b Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK CB2 1EW
Two new bis(acetylide)-functionalised ferrocenylfluorene complexes, 9-ferrocenylmethylene-2,7-bis-
(trimethylsilylethynyl)fluorene 1 and -2,7-bis(ethynyl)fluorene 2, have been prepared in good yield by
condensation of ferrocenecarbaldehyde with 2,7-bis(trimethylsilylethynyl)fluorene and the subsequent
desilylation of 1. Treatment of trans-[PtPh(Cl)(PEt3)2] with half an equivalent of 2 in CH2Cl2–NHPri2,
in the presence of CuI, at room temperature, gives the dimeric platinum() complex trans-[Ph(Et3P)2-
᎐
᎐
Pt᎐C᎐CRC᎐C᎐Pt(PEt ) Ph] 3 (R = 9-ferrocenylmethylenefluorene-2,7-diyl) in 56% yield. Soluble polymeric
᎐
᎐
3
᎐
2
n
᎐
trans-[{-Pt(PBu ) -C᎐CRC᎐C-} ] 4 has been obtained in good yield by the CuI-catalysed dehydrohalogenation
᎐
᎐
3
2
n
of trans-[Pt(PBun )2Cl2] with 2 (1:1 molar ratio) in an amine solvent. Optical measurements on the thin films
3
indicated that there is a significant reduction in the bandgap value for polymer 4 (2.1 eV) as compared to that
n
᎐
᎐
of trans-[{-Pt(PBu ) -C᎐CRC᎐C-} ] 5 (R = fluorene-2,7-diyl) (2.9 eV) without the ferrocenyl moiety, featuring
᎐
᎐
3
2
n
the importance of donor–acceptor interaction in such conjugated systems. All the new compounds have been
characterised by analytical, spectroscopic and electrochemical methods, and the single-crystal structures of
2, 3 and 5 have been established.
There has been considerable interest in the chemistry of soluble
conjugated organometallic materials in view of their potential
applications in photocells, field-effect transistors, light-emitting
diodes or molecules for non-linear optics (NLO).1 Research
into ferrocene-containing complexes and polymers is under-
going something of a ‘renaissance’ since ferrocene has long
been recognised as being able to stabilise α-carbocations and
can act as a good donor for an NLO-phore.2 On the other hand,
fluorene electron acceptors are widely used as electron trans-
port materials.3 Based on the recent development in organic
polymers in which their bandgaps can be reduced by the
copolymerisation of donor and acceptor units,4 it was envis-
aged that fluorenylferrocenes would constitute an interesting
new class of spacer units in the novel organometallic polyyne
systems and their electronic properties might reduce the energy
difference of the HOMO Ϫ LUMO bandgap.
Bearing these concepts in mind we set out to synthesize
new ferrocenylfluorenes acetylide-substituted at the 2 and 7
positions which can afford trimetallic (M᎐Fe᎐M) or polymeric
materials. Here, we report results on the synthesis of the first
examples of platinum() acetylide-functionalised fluorene
complexes and polymers bearing a pendant ferrocene group in
the side chain. The crystal structures of related dimeric model
complexes are also reported.
converted readily into 2 in 68% yield. Complex 3 and the
polymer 4 were synthesized by the dehydrohalogenation
reaction between trans-[PtPh(Cl)(PEt3)2] or trans-[Pt(PBun )2-
3
Cl2] with 2 in NHPri2, with a catalytic amount of CuI, following
a procedure reported for related platinum() acetylide com-
plexes.6 Compound 3 was purified by silica TLC and recrystal-
lisation from CH2Cl2–hexane gave air-stable red crystals in
moderate yield (56%). Complexes 1–3 have been characterised
by satisfactory elemental analyses, mass spectrometry (EI or
FAB), IR and NMR spectroscopies. Purification of the poly-
mer 4 was achieved by alumina column chromatography using
CH2Cl2 as eluent, and it was isolated in high purity and good
yield (60%). It is soluble in common organic solvents and
readily casts tough free-standing red films. The weight-average
molecular weight (Mw) value of 34 540 (polydispersity =
1.922) for 2 determined by gel permeation chromatography
shows a high degree of polymerisation. The number-average
molecular weight (Mn) corresponds to 18 repeat units per
polymer chain.
Optical, electrochemical and thermal properties
The trans geometry of the Pt(PR3)2 (R = Et or Bun) unit in the
dimer 3 and polymer 4 was clearly revealed by the simple singlet
pattern of their νC᎐C IR and 31P-{1H} NMR spectra. For all the
᎐
new compounds, proton signals stemming from the ferrocenyl
group were observed. The 1JPt᎐P coupling constant for 3 is larger
than that for 4 by about 280 Hz.
Results and Discussion
Syntheses
The electronic absorption spectra of compounds 3 and 4
both display strong absorptions in the UV range at ca. 355–382
nm in CH2Cl2, tentatively assigned as ligand-localised trans-
itions. Longer wavelength transitions due to metal-to-ligand
charge transfer (MLCT) appear as shoulders at 434 (for 3) and
437 nm (for 4). It is found that the bandgap (onset of absorp-
tion) value Eg of the thin film of 4 is 2.1 eV, lower than those
found in the corresponding non-ferrocenyl substituted polymer
55 (Eg = 2.9 eV) and other platinum() polyynes with phenyl,7
The synthesis of all new compounds are outlined in Scheme 1.
The new ferrocenylfluorene complex 1 was prepared in 80%
yield by condensing 2,7-bis(trimethylsilylethynyl)fluorene5 with
ferrocenecarbaldehyde in dry thf using lithium diisopropyl-
amide. Upon deprotection with K2CO3 in Et2O–MeOH, 1 was
† E-Mail: rwywong@net1.hkbu.edu.hk
‡ Non-SI unit employed: eV ≈ 1.60 × 10Ϫ19 J.
J. Chem. Soc., Dalton Trans., 1998, Pages 2761–2766
2761

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Fe
H
(i)
Me3Si
Me3Si
SiMe3
SiMe3
1
(ii)
Fe
Fe
H
H
(iii)
Ph(Et3P)2Pt
H
Pt(PEt3)2Ph
H
3
2
(iv)
Fe
H
PBun
Pt
3
PBun
3
n
4
Scheme 1 (i) LiNPri2, Ϫ78 ЊC, ferrocenecarbaldehyde; (ii) K2CO3, MeOH; (iii) trans-[PtPh(Cl)(PEt3)2], NHPri2, CuI; (iv) trans-[Pt(PBun )2Cl2],
3
NHPri2, CuI
Table 1 Electrochemical data for the ferrocenylfluorenes and their
platinum() complexes
₁
Compound
Oxidation, E /V*
₂
1
2
3
4
ϩ0.60
ϩ0.59
ϩ0.67 (ϩ1.16)
ϩ0.71 (ϩ1.34)
* 0.1 mol dmϪ3 NBun BF4 in CH2Cl2, platinum electrode, scan rate
4
100 mV sϪ1, reference silver wire, irreversible waves are shown in
parentheses.
pyridyl,8 oligothienyl9 or alkynyl10 units. It is envisioned that
the presence of a pendant ferrocenyl donor unit in the side
chain of these soluble organometallic polyynes is particu-
larly attractive as
a new approach for controlling the
energy gap of this kind of polymeric materials. A reduction in
the HOMO Ϫ LUMO energy separation in such donor–
acceptor based polymers provides us with valuable inform-
ation in the design of more useful materials for device
applications.
Fig. 1 Molecular structure of complex 2 showing the atomic number-
ing. Ellipsoids are drawn at the 50% probability level
Cyclic voltammetry of the new materials, in CH2Cl2, shows a
reversible oxidation in each case, attributable to the ferrocene–
ferrocenium couple (Table 1). The platinum σ-acetylides 3 and 4
also show an irreversible oxidation wave at greater potentials,
assigned to the oxidation of the platinum residue. As expected,
the half-wave potential of the ferrocene moiety is slightly more
anodic in complexes 3 and 4 than in 1 and 2 because of the
loss of electron density from the ferrocenyl donor unit to the
net electron-accepting platinum centre through the acetylide
bridge.
Mass loss of 30% was, however, detected when it was heated to
500 ЊC.
Crystal structure analyses
The molecular structure of the precursor complex 2, as deter-
mined crystallographically, is shown in Fig. 1, which includes
the atom numbering scheme. Selected bond distances and
angles are listed in Table 2. In the solid state the molecule con-
sists of a ferrocene unit appended to the fluorenyl moiety at the
9 position via C(1) atom [C(1)᎐C(2) 1.348(3) and C(1)᎐C(19)
1.465(3) Å]. The two cyclopentadienyl rings of the ferrocene
group are planar and exhibit a staggered conformation. The
The thermal behaviour of the Pt᎐Fe mixed polymer 4 was
studied and it showed a relatively good thermal stability as
confirmed by thermogravimetry (10 ЊC minϪ1 under N2), which
indicated that no decomposition occurred up to ca. 250 ЊC.
2762
J. Chem. Soc., Dalton Trans., 1998, Pages 2761–2766

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᎐
᎐
᎐
C᎐C bond distance [average 1.176(5) Å] is typical of terminal
acetylide σ bonding and the Pt᎐C᎐C(fluorenyl)C᎐C᎐Pt frag-
᎐
᎐
᎐
acetylides reported previously.5,6
ment is essentially planar. In 3 the fluorenyl ring system makes a
dihedral angle of 39( 1)Њ with the η5-C5H4 ring, which is differ-
ent from that observed in the vinyl ferrocene systems, where the
nature of the substituent tends to control the planarity.11 The
exo double bond C(1)᎐C(14) is distorted from planarity by 5Њ
[defined by C(13)᎐C(1)᎐C(14)᎐C(15)]. As in 2 there is a shorten-
ing of the C(14)᎐C(15) bond and lengthening of the C(1)᎐C(14)
bond in 3 [C(1)᎐C(14) 1.37(2) and C(14)᎐C(15) 1.44(2) Å]. The
two cyclopentadienyl rings are essentially parallel, with a ring
tilt angle of 3.1Њ, and the ferrocenyl group is nearly eclipsed in
the solid state. For 5ؒ0.33C6H14 there are one and a half
molecules in the asymmetric unit, and only the complete unique
molecule is shown in Fig. 3; the half molecule is disordered
about a centre of inversion. The Pt᎐P bond lengths lie in the
range of 2.274(4)–2.292(4) (3) and 2.267(5)–2.284(4) Å (5),
which are similar to those observed in other Pt᎐PR3 acetylide
The solid-state structures of complexes 3 and 5 have also
been determined by X-ray crystallography. The molecular struc-
tures are depicted in Figs. 2 and 3, respectively, and selected
bond parameters are in Tables 3 and 4. From a fundamental
viewpoint, the π-conjugated diyne-bridged diplatinum()
complex 3 is investigated as a model for the electronic,
electrochemical and structural properties of the parent polymer
4. In each case, the co-ordination geometry at each platinum
atom is square planar with the two PEt3 groups in a trans
arrangement. The C᎐C bond length is characteristic of metal–
᎐
᎐
Table 2 Selected bond lengths (Å) and angles (Њ) for compound 2
Fe᎐C(19)
Fe᎐C(21)
Fe᎐C(23)
Fe᎐C(25)
Fe᎐C(27)
C(1)᎐C(19)
C(15)᎐C(16)
2.069(2)
2.042(3)
2.037(2)
2.047(3)
2.050(3)
1.465(3)
1.180(4)
Fe᎐C(20)
Fe᎐C(22)
Fe᎐C(24)
Fe᎐C(26)
Fe᎐C(28)
C(1)᎐C(2)
C(17)᎐C(18)
2.046(3)
2.045(3)
2.048(2)
2.046(3)
2.055(3)
1.348(3)
1.171(5)
complexes. The average bond angle of 176(1)Њ for the fragment
Pt᎐C᎐C in both 3 and 5 conforms to the linear geometry of the
᎐
᎐
bis(acetylide) complexes.
Experimental
General
C(2)᎐C(1)᎐C(19)
C(5)᎐C(15)᎐C(16)
128.3(2)
177.8(3)
C(1)᎐C(2)᎐C(3)
C(12)᎐C(17)᎐C(18)
131.6(2)
176.7(3)
Solvents were predried and distilled from appropriate drying
Fig. 2 Molecular structure of complex 3 showing the numbering scheme. Hydrogen atoms and disorder of the ethyl groups attached to P(4) have
been omitted for clarity. Ellipsoids are shown at the 50% probability level
Fig. 3 Molecular structure of complex 5 with the atomic numbering. Ellipsoids are at the 50% probability level
J. Chem. Soc., Dalton Trans., 1998, Pages 2761–2766
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on 1 mm silica plates prepared in our laboratories. Column
chromatography was performed either on Kieselgel 60 (230–400
mesh) silica gel or alumina (Brockman Grade II-III).
Table 3 Selected bond lengths (Å) and angles (Њ) for compound 3
Pt(1)᎐P(1)
Pt(1)᎐C(29)
Pt(2)᎐P(3)
Pt(2)᎐C(35)
C(25)᎐C(26)
C(27)᎐C(28)
C(1)᎐C(14)
Fe᎐C(15)
Fe᎐C(17)
Fe᎐C(19)
Fe᎐C(21)
Fe᎐C(23)
2.290(4)
2.09(1)
2.274(4)
2.07(1)
1.22(2)
1.21(2)
1.37(2)
2.05(1)
2.04(2)
2.04(2)
2.03(2)
2.01(2)
Pt(1)᎐P(2)
Pt(1)᎐C(26)
Pt(2)᎐P(4)
Pt(2)᎐C(28)
C(4)᎐C(25)
C(11)᎐C(27)
C(14)᎐C(15)
Fe᎐C(16)
Fe᎐C(18)
Fe᎐C(20)
Fe᎐C(22)
Fe᎐C(24)
2.292(4)
2.00(1)
2.287(4)
2.00(1)
1.47(2)
1.45(2)
1.44(2)
2.05(1)
1.96(2)
2.06(2)
1.97(2)
1.96(2)
Preparations of fluorene derivatives
Compound 1. A chilled (Ϫ78 ЊC) thf (30 cm3) solution
containing diisopropylamine (0.24 g, 2.3 mmol) was treated
with LiBun (1.8 cm3, 2.9 mmol) and then warmed to 0 ЊC over
a period of 30 min to give a pale yellow solution. The reaction
mixture was cooled to Ϫ78 ЊC again and 2,7-bis(trimethyl-
silylethynyl)fluorene (0.82 g, 2.3 mmol) added in one portion.
The orange mixture was stirred for 5 min and then ferro-
cenecarbaldehyde (0.50 g, 2.3 mmol) added. The cooling bath
was removed and stirring continued for 2 h. The deep red
solution was diluted with Et2O (100 cm3) and then washed
with water (2 × 100 cm3) and finally with brine (100 cm3). The
organic layer was dried over MgSO4 and the solvents removed
under reduced pressure. The crude product was recrystallised
from CHCl3 to afford 1.02 g of pure compound 1 (80%). IR
P(1)᎐Pt(1)᎐P(2)
P(2)᎐Pt(1)᎐C(26)
P(3)᎐Pt(2)᎐P(4)
P(4)᎐Pt(2)᎐C(28)
C(4)᎐C(25)᎐C(26)
C(13)᎐C(1)᎐C(14)
179.1(2)
93.0(4)
177.6(2)
88.1(4)
176(1)
P(1)᎐Pt(1)᎐C(26)
Pt(1)᎐C(26)᎐C(25)
P(3)᎐Pt(2)᎐C(28)
Pt(2)᎐C(28)᎐C(27)
C(11)᎐C(27)᎐C(28)
C(1)᎐C(14)᎐C(15)
86.8(4)
173(1)
92.2(4)
178(1)
175(1)
130(1)
130(1)
1
(CH2Cl2): 2152 (νC᎐C) cmϪ1. H NMR (CDCl3): δ 0.25 (s, 9 H,
᎐
SiMe3), 0.30 (s, 9 H, SiMe3), 4.22 (s, 5 H, C5H5), 4.53 (t, 2 H,
JH᎐H = 1.8, C5H4), 4.74 (t, 2 H, JH᎐H = 1.8, C5H4), 7.42–7.49 (m,
3 H, arene and vinyl CH), 7.54, 7.62 (2d, 2 H, JH᎐H = 4.0 Hz,
arene CH) and 8.39 (s, 1 H, arene CH). 13C-{1H} NMR
Table 4 Selected bond lengths (Å) and angles (Њ) for compound 5
Molecule 1
(CDCl3): δ 0.07, 0.12 (SiMe3), 69.66 (C5H5 CH), 70.37, 71.09
Pt(1)᎐P(1)
Pt(1)᎐C(1)
Pt(2)᎐P(3)
Pt(2)᎐C(24)
C(7)᎐C(8)
C(20)᎐C(22)
2.273(5)
2.06(2)
2.269(5)
2.03(2)
1.17(2)
1.43(2)
Pt(1)᎐P(2)
Pt(1)᎐C(7)
Pt(2)᎐P(4)
Pt(2)᎐C(23)
C(8)᎐C(9)
C(22)᎐C(23)
2.284(4)
2.02(2)
2.273(5)
2.03(2)
1.45(2)
1.18(2)
᎐
(C H CH), 80.57 (ipso-C of C H ), 94.20, 94.29 (C᎐C), 106.01,
᎐
5
4
5
4
᎐
106.05 (C᎐C), 119.69, 119.80, 123.17, 127.74, 128.62, 131.18,
᎐
131.59 (arene or vinyl CH), 121.39, 121.56, 131.76, 137.08,
137.51, 139.89 and 140.32 (arene C). EI mass spectrum: m/z 554
(Found: C, 73.01; H, 6.30. Calc. for C34H34FeSi2: C, 73.63; H,
6.18%).
P(1)᎐Pt(1)᎐P(2)
P(2)᎐Pt(1)᎐C(7)
P(3)᎐Pt(2)᎐P(4)
P(4)᎐Pt(2)᎐C(23)
C(7)᎐C(8)᎐C(9)
177.0(2)
91.7(5)
171.6(2)
91.8(5)
176(1)
P(1)᎐Pt(1)᎐C(7)
Pt(1)᎐C(7)᎐C(8)
P(3)᎐Pt(2)᎐C(23)
Pt(2)᎐C(23)᎐C(22)
C(20)᎐C(22)᎐C(23)
90.1(5)
174(1)
87.5(5)
177(1)
173(2)
Compound 2. The compound 1 (0.20 g, 0.36 mmol) and
K2CO3 (0.05 g, 0.36 mmol) were combined in MeOH–Et2O (40
cm3, 1:1 v/v) and the mixture was stirred at room temperature
for 20 h. Infrared spectroscopy showed that all the starting
material had been consumed. Upon removal of solvent under
reduced pressure, the deep red residue was purified by column
chromatography on silica using hexane–CH2Cl2 (1:1 v/v) as
eluent to afford a major deep red powder identified as 2 (0.10 g,
Molecule 2
Pt(3)᎐P(5)
Pt(3)᎐C(54)
C(72)᎐C(73)
2.276(6)
2.05(2)
1.20(2)
Pt(3)᎐P(6)
Pt(3)᎐C(72)
C(73)᎐C(74)
2.267(5)
2.01(2)
1.42(2)
1
68%). IR (CH2Cl2): 2106 (νC᎐C), 3298 (ν᎐CH) cmϪ1. H NMR
᎐
᎐
P(5)᎐Pt(3)᎐P(6)
P(6)᎐Pt(3)᎐C(72)
C(72)᎐C(73)᎐C(74)
175.6(2)
88.9(5)
174(1)
P(5)᎐Pt(3)᎐C(72)
Pt(3)᎐C(72)᎐C(73)
90.8(6)
176(1)
᎐
᎐
(CDCl ): δ 3.08 (s, 1 H, C᎐CH), 3.16 (s, 1 H, C᎐CH), 4.23 (s, 5
᎐
᎐
3
H, C5H5), 4.54 (t, 2 H, JH᎐H = 1.83, C5H4), 4.73 (t, 2 H,
JH᎐H = 1.83, C5H4), 7.46–7.52 (m, 3 H, arene and vinyl CH),
7.65, 7.69 (2d, 2 H, JH᎐H = 4.0 Hz, arene CH), 7.91 (s, 1 H, arene
CH) and 8.40 (s, 1 H, arene CH). 13C-{1H} NMR (CDCl3):
agents.12 All chemicals, except where stated, were from com-
᎐
δ 69.69 (C5H5 CH), 70.48, 71.03 (C5H4 CH), 77.18 (C᎐C),
᎐
mercial sources and used without further purification. The com-
᎐
80.46 (ipso-C of C5H4), 84.45 (C᎐C), 119.84, 119.94, 123.45,
᎐
pounds trans-[PtPh(Cl)(PEt3)2]13 and trans-[Pt(PBun )2Cl2]14
3
127.91, 128.95, 131.21, 131.67 (arene or vinyl CH), 120.40,
120.61, 131.58, 137.15, 137.68, 140.05 and 140.33 (arene C). EI
mass spectrum: m/z 410 (Found: C, 81.56; H, 4.60. Calc. for
C28H18Fe: C, 81.97; H, 4.42%).
were prepared via literature methods. The synthesis of the
fluorene derivative Me SiC᎐CRC᎐CSiMe (R = fluorene-2,7-
᎐
᎐
᎐
᎐
3
3
diyl) has been reported recently.5 The NMR spectra were
recorded on a Bruker WM-250 or AM-400 and JEOL EX270
spectrometers in appropriate solvents, 31P-{1H} referenced to
external trimethyl phosphite and the 1H and 13C-{1H} to
solvent resonances. Infrared spectra were recorded as CH2Cl2
solutions, in a NaCl cell, on a Perkin-Elmer 1000 or 1710
FT-IR spectrometer, mass spectra on a Kratos MS890 or
Finnigan MAT SSQ710 spectrometer by either the electron
impact (EI) or fast atom bombardment (FAB) technique. Cyclic
voltammetric measurements were made with a Princeton
Applied Research (PAR) model 273A potentiostat. The
supporting electrolyte was 0.1 mol dmϪ3 NBu4BF4 in CH2Cl2.
Microanalyses were performed in the University Chemical
Laboratory, University of Cambridge. Electronic absorption
spectra were obtained with a Perkin-Elmer Lambda UV/NIR
or Hewlett-Packard UV/VIS spectrometer. The TGA studies
were performed using a Shimadzu DT-40 thermal analyser.
Preparative thin-layer chromatography (TLC) was carried out
on commercial Merck plates with a 0.25 mm layer of silica, or
Dimer and polymer preparations
Compound 3. To a mixture of compound 2 (82 mg, 0.2 mmol)
and 2 equivalents of trans-[PtPh(Cl)(PEt3)2] (0.22 g, 0.4 mmol)
in CH2Cl2–NHPri2 (50 cm3, 1:1 v/v) was added CuI (3 mg). The
solution was stirred at room temperature over 15 h, after which
all volatile components were removed. The product was puri-
fied on preparative TLC plates with hexane–CH2Cl2 (1:1 v/v)
as eluent, giving compound 3 as a red crystalline solid in an
isolated yield of 56% (0.16 g) after recrystallisation from
CH2Cl2–hexane. IR (CH2Cl2): 2088 (νC᎐C) cmϪ1 1H NMR
.
᎐
(CDCl3): δ 1.09 (m, 36 H, Me), 1.76 (m, 24 H, PCH2), 4.20 (s, 5
H, C5H5), 4.38 (t, 2 H, C5H4), 4.72 (t, 2 H, C5H4), 6.79 (m, 2 H,
Hpara of Ph), 6.95 (m, 4 H, Hmeta of Ph), 7.28 (m, 7 H, Hortho of
Ph ϩ arene and vinyl CH), 7.45, 7.48 (2d, 2 H, JH᎐H = 1.9 Hz,
arene CH), 7.65 (s, 1 H, arene CH) and 8.11 (s, 1 H, arene CH).
31P-{1H} NMR (CDCl3): δ Ϫ131.73 (1JPt᎐P = 2634 Hz). FAB
2764
J. Chem. Soc., Dalton Trans., 1998, Pages 2761–2766

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Table 5 Summary of crystallographic data for compounds 2, 3 and 5ؒ0.33C6H14
2
3
5ؒ0.33C6H14
Empirical formula
M
C28H18Fe
410.27
C64H86FeP4Pt2
1425.31
C53H78P4Pt2ؒ0.33C6H14
1256.85
Crystal colour, habit
Crystal dimensions/mm
Crystal system
Space group
Red block
0.30 × 0.20 × 0.20
Monoclinic
C2/c
Red needle
0.32 × 0.08 × 0.07
Triclinic
Off-white plate
0.23 × 0.18 × 0.07
Triclinic
¯
¯
P1
P1
a/Å
b/Å
c/Å
α/Њ
24.488(3)
10.467(2)
14.773(2)
12.298(1)
13.810(1)
18.768(1)
90.42(1)
94.56(1)
91.92(1)
3175.4(4)
2
1.491
1424
4.739
298
9.220(1)
19.960(1)
22.910(2)
102.76(2)
93.83(2)
93.69(2)
4089.3(8)
3
1.534
1890
5.256
298
β/Њ
97.06(3)
γ/Њ
U/Å3
3758(1)
8
1.450
1696
0.814
150
Z
Dc/g cmϪ3
F(000)
µ(Mo-Kα)/mmϪ1
T/K
2θmax/Њ
50.5
15 770
3322
0.0719
3311 (n = 2)
50.9
52.1
No. reflections collected
No. independent reflections
Rint
Observed reflections
[I > nσ(I)]
25 398
10 132
0.044
34 086
12 311
0.056
6008 (n = 3)
6006 (n = 3)
No. refined parameters
Residuals
263
472
767
R1 = 0.048a
wR2 = 0.090b
1.188 (on F2)d
ϩ0.35, Ϫ0.57
R = 0.053a
RЈ = 0.068c
1.96 (on F)e
ϩ0.52, Ϫ2.48
R = 0.054
RЈ = 0.061
1.34 (on F)e
ϩ2.54, Ϫ2.04
Goodness of fit
Residual electron density/e ÅϪ3
¹
¹
a R = R1 = Σ||Fo| Ϫ |Fc||/Σ|Fo|. b wR2 = [Σw(Fo2 Ϫ Fc2)2/Σw(Fo )2]². c RЈ = [Σw(|Fo| Ϫ |Fc|)2/Σw(Fo)2]². d Goodness of fit = [Σw(Fo2 Ϫ Fc2)2/(Nobs Ϫ
2
¹
¹
Nparam)]², based on all data. e Goodness of fit = [Σw(|Fo| Ϫ |Fc|)2/(Nobs Ϫ Nparam)]², based on all data.
mass spectrum: m/z 1425. UV/VIS (CH2Cl2): λmax/nm 434
(ε 5.1 × 103 dm3 molϪ1 cmϪ1) (Found: C, 53.58; H, 5.93. Calc.
for C64H86FeP4Pt2: C, 53.93; H, 6.04%).
time of 10 min, and then the crystal was rotated through
90Њ about an axis 45Њ to the vertical and 40 × 3Њ frames with
10 min exposure were employed for data acquisition. For 3 and
5ؒ0.33C6H14 60 × 3Њ frames with an exposure time of 5 min per
frame were used. The intensity data were corrected for Lorentz-
polarisation effects and interframe scaling was applied.
The structure of compound 2 was solved by direct methods
(SHELXTL PLUS)15 and subsequent Fourier-difference
syntheses, and refined by full-matrix least squares on F2
(SHELXL 93)16 with anisotropic displacement parameters for
all non-H atoms. The structures of 3 and 5ؒ0.33C6H14 were
solved by Patterson methods (DIRDIF 92 PATTY)17 and
refined on F by least squares. For 3 the ethyl groups attached to
the P(4) atom showed positional disorder and they were refined
with a two-sites model with occupancy factors of 0.5 each. For
5ؒ0.33C6H14 the crystal structure contains one and a half
molecules in the asymmetric unit, the half molecule being
related to its symmetry equivalent through a centre of inversion
which sits at the centre of the fluorene ring. This model
assumed that the fluorene ring exhibited twofold disorder in the
crystal and therefore a pseudo-inversion centre was generated.
The fluorene atom positions were then assigned with isotropic
displacement parameters and refined in two sites with 50%
occupancy. In each case, hydrogen atoms were generated in
their idealised positions.
Compound 4. A mixture of trans-[Pt(PBun )2Cl2] (0.1 g, 0.15
3
mmol) and 1 equivalent of the diterminal alkyne 2 (61.5 mg,
0.15 mmol) was dissolved in CH2Cl2–NHPri2 (50 cm3, 1:1 v/v)
and CuI (3 mg) subsequently added. After stirring for 15 h the
mixture was evaporated to dryness. The residue was redissolved
in CH2Cl2 and filtered through a short alumina column using
the same eluent to give a red solution of compound 4. After
removal of solvent by a rotary evaporator, a deep red polymer
film of 4 was obtained and it was then washed with MeOH to
give 4 in 60% yield (0.09 g). IR (CH2Cl2): 2095 (νC᎐C) cmϪ1. 1H
᎐
NMR (CDCl3): δ 0.93 (m, 18 H, Me), 1.50 (m, 24 H, CH2), 2.18
(m, 12 H, PCH2), 4.18 (s, 5 H, C5H5), 4.39 (s, 2 H, C5H4), 4.70
(s, 2 H, C5H4), 7.31 (m, 3 H, arene and vinyl CH), 7.48 (2d,
2 H, arene CH), 7.63 (s, 1 H, arene CH) and 8.09 (s, 1 H, arene
CH). 31P-{1H} NMR (CDCl3): δ Ϫ138.39 (1JPt᎐P = 2358 Hz).
UV/VIS (CH2Cl2): λmax/nm 437 (ε 7.9 × 103 dm3 molϪ1 cmϪ1).
Mw = 34 540, Mn = 17 970 (n = 1.922) (Found: C, 61.29; H, 7.24.
Calc. for C52H70FeP2Pt: C, 61.96; H, 7.00%).
Crystallography
CCDC reference number 186/1055.
Red crystals of compounds 2 and 3 suitable for X-ray diffrac-
tion studies were grown by slow evaporation of their respective
solutions in hexane–CH2Cl2. Off-white crystals of 5ؒ0.33C6H14
were obtained from its hexane solution by evaporation at room
temperature. Geometric and intensity data were collected using
graphite-monochromated Mo-Kα radiation (λ = 0.71 073 Å) on
Rigaku R-Axis IIc image plate (for 2) and MAR Research
image plate scanners (for 3 and 5ؒ0.33C6H14). All pertinent
crystallographic data and other experimental details are
summarised in Table 5. For 2 two data sets were collected; one
of them involved 60 × 3Њ oscillation frames with an exposure
Acknowledgements
We thank the Hong Kong Baptist University (W.-K. W. and
W.-Y. W.) for financial support.
References
1 J. J. M. Halls, C. A. Walsh, N. C. Greenham, E. A. Marseglia, R. H.
Friend, S. C. Moratti and A. B. Holmes, Nature (London), 1995, 376,
498; F. Garnier, R. Haijalaoui, A. Yassar and P. Srivastava,
J. Chem. Soc., Dalton Trans., 1998, Pages 2761–2766
2765

View Article Online
Science, 1994, 265, 1684; J. R. Sheats, H. Antoniadis, M. Hueschen,
W. Leonard, J. Miller, R. Moon, D. Roitman and A. Stocking,
Science, 1996, 273, 884; N. J. Long, Angew. Chem., Int. Ed. Engl.,
1995, 34, 21.
2 C. Zou and M. S. Wrighton, J. Am. Chem. Soc., 1990, 112, 7578;
M. H. L. Green, S. R. Marder, M. E. Thompson, J. A. Bandy, D.
Bloor, P. V. Kolinsky and R. J. Jones, Nature (London), 1987, 330,
360.
3 M. Matsui, K. Shibata, H. Muramatsu and H. Nakazumi, J. Mater.
Chem., 1996, 6, 1113.
4 E. E. Havinga, W. Hoeve and H. Wynberg, Synth. Met., 1993,
55–57, 229.
9 N. Chawdhury, A. Köhler, R. H. Friend, W. Y. Wong, J. Lewis,
M. Younus, P. R. Raithby, T. C. Corcoran, M. R. A. Al-Mandhary
and M. S. Khan, J. Chem. Phys., in the press.
10 B. F. G. Johnson, A. K. Kakkar, M. S. Khan, J. Lewis, A. E. Dray,
R. H. Friend and F. Wittmann, J. Mater. Chem., 1991, 1, 485.
11 M. E. Wright and E. G. Toplikar, Macromolecules, 1992, 25,
6050.
12 W. L. F. Armarego and D. D. Perrin, Purification of Laboratory
Chemicals, 4th edn., Butterworth-Heinemann, London, 1996.
13 J. Chatt and B. L. Shaw, J. Chem. Soc., 1960, 4020; W. Müller,
G. Schmidtberg and H. Brune, Chem. Ber., 1985, 118, 4653.
14 G. B. Kauffman and T. A. Teter, Inorg. Synth., 1963, 7, 247.
15 G. M. Sheldrick, SHELXTL PLUS, Siemens Analytical Instruments,
Madison, WI, 1990.
5 J. Lewis, P. R. Raithby and W. Y. Wong, J. Organomet. Chem., 1998,
556, 219.
6 J. Lewis, N. J. Long, P. R. Raithby, G. P. Shields, W. Y. Wong and
M. Younus, J. Chem. Soc., Dalton Trans., 1997, 4283.
7 S. J. Davies, B. F. G. Johnson, M. S. Khan and J. Lewis, J. Chem.
Soc., Chem. Commun., 1991, 187; H. F. Wittmann, K. Fufrmann,
R. H. Friend, M. S. Khan and J. Lewis, Synth. Met., 1993, 55–57,
56; A. E. Dray, R. Rachel, W. O. Saxton, J. Lewis, M. S. Khan,
A. M. Donald and R. H. Friend, Macromolecules, 1992, 25, 3473.
8 N. Chawdhury, A. Köhler, R. H. Friend, M. Younus, N. J. Long,
P. R. Raithby and J. Lewis, Macromolecules, 1998, 31, 722.
16 G. M. Sheldrick, SHELXL 93, University of Göttingen, 1993.
17 P. T. Beurskens, G. Admiraal, G. Beurskens, W. P. Bosman,
S. Garcia-Granda, R. O. Gould, J. M. M. Smits and C. Smykalla,
PATTY, The DIRDIF program system, Technical Report of the
Crystallography Laboratory, University of Nijmegen, 1992.
Received 28th April 1998; Paper 8/03168A
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