Ethynyl[2.2]paracyclophanes and 4-isocyano[2.2]paracyclophane as ligands in organometallic chemistry

Article abstract of DOI:10.1016/j.jorganchem.2006.10.039

An alternative synthesis of (±)-4-ethynyl[2.2]paracyclophane (PCP{single bond}C{triple bond, long}CH) (5) and 4,16-diethynyl[2.2]paracyclophane (6) via the Corey-Fuchs reaction has been developed. The olefinic intermediate 4-dibromovinyl[2.2]paracyclophan

Full text of DOI:10.1016/j.jorganchem.2006.10.039

Journal of Organometallic Chemistry 692 (2007) 839–850
www.elsevier.com/locate/jorganchem
Ethynyl[2.2]paracyclophanes and 4-isocyano[2.2]paracyclophane
as ligands in organometallic chemistry
a
a,
a,
b
Sebastien Clement , Laurent Guyard *, Michael Knorr *, Stefan Dilsky ,
´
´
b
c
Carsten Strohmann , Marta Arroyo
a
Laboratoire de Chimie des Mate´riaux et Interfaces, Faculte´ des Sciences et des Techniques, 16 route de Gray, 25030 Besanc¸on, France
b
Institut fu¨r Anorganische Chemie der Universita¨t Wu¨rzburg, Am Hubland, D-97074, Wu¨rzburg, Germany
c
Qu´ımica Inorga´nica, Facultad de Ciencias Universidad de Valladolid, 47005 Valladolid, Spain
Received 9 August 2006; received in revised form 15 October 2006; accepted 16 October 2006
Available online 25 October 2006
Dedicated to Prof. Manfred Christl on the occasion of his 65th anniversary.
Abstract
An alternative synthesis of ( )-4-ethynyl[2.2]paracyclophane (PCPAC„CH) (5) and 4,16-diethynyl[2.2]paracyclophane (6) via the
Corey–Fuchs reaction has been developed. The olefinic intermediate 4-dibromovinyl[2.2]paracyclophane (3) has been isolated and struc-
turally characterized. The racemic terminal alkyne 5 was employed as starting material for assembling of a luminescent extended p-con-
jugated system containing
a thiophene unit and for a catalytic bis-silylation reaction yielding the olefinic dithioether
Z-PhSCH2Me2SiC(H)@C(PCP)SiMe2CH2SPh (9). The dimetallatetrahedran [Co2(CO)6(l-g2–PCP–CCH)] (10) has been prepared and
its crystal structure determined by an X-ray diffraction analysis. Alkyne 5 has also been used for the preparation of the Pt(0) complex
[Pt(PPh3)2(PCPAC„CH)] (11) and the heterodinuclear dimetallacyclopentenone [(OC)2Fe{lAC(@O)C(PCP)@C(H)}(l-
dppm)Pt(PPh3)] (12). The synthesis and reactivity of 4-isocyano[2.2]paracyclophane (15) towards heterobimetallic iron–platinum and
palladium–platinum complexes is also presented. Opening of the dative iron ! platinum bond of [(OC)4Fe(l-dppm)PtCl2] (16) occurred
upon addition of 15 to a CH2Cl2 solution of 16 leading to [(OC)4Fe{l-dppm}PtCl2(C„NAPCP)] (17). Treatment of [ClPd(l-
dppm)2PtCl] (18) with isocyanide 15 in a 1:1 ratio affords the A-frame compound [ClPd(l-dppm)2(l-C@NAPCP)PtCl] (19), resulting
from formal insertion of 15 into the Pd–Pt bond. Addition of 2 equiv. of 15–18 leads to the ionic A-frame compound [ClPd(l-
dppm)2(l-C@NAPCP)Pt(C„NAPCP)]Cl (20).
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: [2.2]Paracyclophanes; Alkyne; Isocyanide; Cobalt; Bis-silylation; Iron; Platinum
1. Introduction
(NLO) materials [3], p-conjugated arrays, electron transfer
processes and molecular electronics [4a,4b,4c]. PCP-func-
tionalized chiral metallocenes have been used as olefin
polymerization catalysts after activation with methylalu-
moxane [4d]. Even biomedical applications are emerging
[4e]. Many of these interesting chemical, electrochemical
and photophysical properties arise from the high steric
compression of the neighboring rings (also called decks),
the separation between the ipso-carbons of the stacked
Since the isolation of the parent compound by Brown
and Farthing in 1949 [1a] and its first synthesis by Cram
in 1951 [1b], interest in molecules containing the unique
structural features of [2.2]paracyclophanes (PCP) has never
decreased. PCPs are used for various applications such as
chiral catalysis [2], the design of new optoelectronic
˚
rings being about 2.8 A. The orbital overlap between the
*
Corresponding authors. Fax: +33 3 81 39 66 64 38.
two rings of [2.2]paracyclophane is therefore important
and could possibly lead to an electronic connection
E-mail addresses: laurent.guyard@univ-fcomte.fr (L. Guyard), michael.
knorr@univ-fcomte.fr (M. Knorr).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.10.039

840
S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
PPh3
Cl
Bun
Ru2+
Pd
Zr
N
O
Me
H
A
B
C
Chart 1.
between appropriate substituents on both rings [5]. For this
reason, [2.2]PCP derivatives containing one or two para-
connected carbon–carbon triple bonds have been studied
for organic transformations such as cycloaddition reac-
tions, synthesis of carbon rich compounds and in material
science [6,7,8b]. However, we are not aware of any organo-
metallic complexes bearing a PCP motif attached on a
metal center via a metal–carbon bond, apart from some
examples with g6-coordination of the PCP moiety on
Ru(II) and Cr(0) of type A and the Pd and Zr complexes
B and C having a M–r-aryl bond (Chart 1) [4d,8,9].
As part of our research interest in the activation of alky-
nes by dinuclear transition metal compounds [10], we
embarked on a study on the organometallic reactivity on
this unsaturated compound. In extension of this project,
we attempted also the synthesis of a hitherto unknown iso-
cyano-paracyclophane. This functionalization of a PCP-
building block with an isocyanide group having a reactive
C„N triple bond should also allow an interesting entry
in organometallic chemistry.
Pd-catalyzed Sonogashira coupling and removal of the
alkyne-protecting group [11a,11b,11c]. It seemed for us
desirable to develop first a more convenient and less expen-
sive synthetic alternative leading to ethynyl[2.2]paracyclo-
phanes. The ethynyl derivatives 5 and 6 were prepared
via the Corey–Fuchs reaction in a two-step synthesis [12].
The first step of Scheme 1 implies generation of ylide spe-
cies, formed in situ by the interaction of zinc dust, CBr4
and PPh3, which then react with the formyl derivatives 1–
2 leading to 3–4 in 90–95% yield.
The molecular structure of the vinylic intermediate 3
was elucidated by an X-ray diffraction study (Fig. 1). Note-
worthy is the strong tilding of the vinyl substituent. The
out of plane deformation between the best plane of the aro-
matic cycle defined by C10–C15 and the vinyl plane defined
by Br(1)–Br(2)–C(2)–C(1) amounts to 51.05ꢁ, the dihedral
angle C(10)–C(1)–C(2)–Br(1) being 175.79ꢁ.
Treatment of the dibromoolefins 3 and 4 with 2 equiv. of
n-BuLi in THF at ꢀ78ꢁC, followed by hydrolysis, afforded
after work-up the terminal alkynes 5 and 6 in 80–90% yield.
Several studies have shown that the oxidative addition of
vinyl halides to low-valent Pt-centers leads to Pt(II)
complexes bearing an r-alkenyl ligand [13]. For example,
treatment of [Pt(PPh3)3] with 2,3-dibromobicyclo[2.2.1]-
hept-2-ene results in formation of an isomeric mixture
of cis- and trans-[(3-bromobicyclo[2.2.1]hept-2-en-2-yl)-
(bromo)bis(triphenylphosphine)platinum] [13d]. Unfortu-
nately, oxidative addition of 3 across [Pt(PPh3)4] in toluene
2. Results and discussion
2.1. Syntheses, crystal structure and reactivity of
dibromovinylparcyclophanes
Ethynyl[2.2]PCP’s have been previously prepared by
Hopf and co-workers from formyl derivatives [6b] or via
(i) BuLi, THF, -78˚C
Br
5 R3 = H
6 R3 = C
Br
R3
CH
(ii) H2O
PPh3, CBr4
Zn
CHO
Br
R2
CH2Cl2
R1
PPh3
PPh3
- O=PPh3
Pt(PPh3)4
toluene
Pt
Br
1 R1 = H
2 R1 = CHO
3 R2 = H
4 R2 = CH=CBr2
7
+ PtBr2(PPh3)2
Scheme 1. Synthesis and reactivity of dibromovinylparacyclophanes.

S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
841
cle is similar to that of PCP. It is known that [2.2]paracyc-
lophanes end-capped with oligothiophenes exhibit an
intriguing electrochemistry (enhanced stability of both the
cation radicals and dication oxidation products) [15] and
fluorescence properties (high quantum yield) [16]. In order
to evaluate the effect of the incorporation of an alkynyl-
spacer between a PCP-moiety and a thiophene unit on
the electrochemical and photophysical propensities, we
have prepared the colorless internal alkyne 8. This synthe-
sis was achieved in 85% yield by Pd-catalyzed Sonogashira
coupling of 5 with a-bromothiophene (Scheme 2).
Compound 8 exhibits a well-defined cyclic voltammo-
gram, with formation of the radical cation as indicated
by an irreversible one-electron oxidation at ca. +1.47 V
vs. a silver reference electrode at 100 mV/s. Whereas 5 is
not fluorescent in solution at ambient temperature, the
internal alkyne 8 displays an emission at 378 nm after exci-
tation at 319 nm (Fig. 2).
We have recently reported on the chemistry of
1,1,2,2-tetramethyl-1,2-bis(diphenylthiomethyl)disilane and
exploited its potential for catalytic bis-silylation (double
silylation) reactions [17]. In a similar manner, 5 was bis-
silylated using Pd(OAc)2/1,1,3,3-tetramethylbutylisocyanide
as catalyst (Scheme 2), affording the olefinic dithioether 9
in 67% yield. The structural assignment of this yellow waxy
solid, which displays a cis configuration about the olefinic
double bond, is strongly supported by its spectroscopic
data. In the 1H NMR spectrum, the 4 diastereotopic
Si–CH3 groups appear at d 0.25, 0.30, 0.54 and 0.59 as sin-
glet resonances, the vinylic hydrogen is found at d 6.20.
Due to the non-equivalence of the SiCH2SPh groups, the
29Si{1H} spectrum consists of two singlets at d = ꢀ6.53
and ꢀ9.94 ppm.
˚
Fig. 1. View of the crystal structure of 3. Selected bond lengths (A) and
angles (ꢁ): C(2)–Br(1) 1.885(2), C(2)–Br(2) 1.883(2), C(1)–C(2) 1.320(3),
C(1)–C(10) 1.474(3); Br(1)–C(2)–Br(2) 113.63(12), Br(1)–C(2)–C(1)
120.92(19), Br(2)–C(2)–C(1) 125.44(19), C(2)–C(1)–C(10) 128.1(2), C(1)–
C(10)–C(11) 120.3(2), C(1)–C(10)–C(15) 120.0(2).
at 70 ꢁC was less straight forward. Examination of the
crude reaction mixture revealed formation of a large
amount of cis-[PtBr2(PPh3)2] (ca. 45%, singlet at d 14.8
1
with J(Pt–P) = 3614 Hz) [14], some O@PPh3, and some
other minor species. In addition, a doublet of doublets res-
onance centered at 15.3 and 13.7 with a 2J(P–P) coupling of
15 Hz was observed (ca. 35%). We tentatively attribute the
latter AX-type signal, which is flanked by 195Pt satellites
1
with rather large J(Pt–P) couplings of 3611 and 3645 Hz,
to the r-alkenyl complex 7, having two cis-arranged PPh3
ligands. Unfortunately, we did not succeed to separate
the reaction mixture; therefore, a complete and unambigu-
ous characterization of 7 was not possible.
2.3. Coordination of ( )-4-ethynyl[2.2]paracyclophane on
transition metals
2.2. Functionalization of ( )-4-ethynyl[2.2]paracyclophane
with main group elements
Transition metal-mediated organic transformations
serve more and more as a valuable tool for synthetic chem-
ists [18a]. Important examples are Co2(CO)8-mediated
reactions. The most widely known process involving
The choice of PCP as tunable center appears especially
attractive in combination with a thiophene unit since the
electron affinity of the p-electron-rich thiophene heterocy-
S
Br
S
Et NH, 50 C; PdCl (PPh ) / CuI
˚
2
2
3 2
8
PhS
Si
PhS
Si
Si
SPh
5
SPh
Si
Pd(OAc)2
1,1,3,3-tetramethylbutylisocyanide
toluene, 110 C
H
9
˚
Scheme 2. Functionalization of racemic of ( )-4-ethynyl[2.2]paracyclophane.

842
S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
Absorption
Emission
0.6
0.4
0.2
0.0
200
300
400
500
600
Wavelength (nm)
Fig. 2. Normalized absorption and emission spectra of 8 in CH2Cl2 at
298 K.
Co2(CO)8 is the [2+2+1] cycloaddition of alkynes, alkenes
and carbon monoxide (Pauson–Khand reaction) for the
preparation of cyclopentenones [18b,18c]. This reagent is
furthermore known to mediate alkyne trimerisation or to
catalyse hydrosilylation reaction across the C„C bond
[19,20]. 5 reacts smoothly at room temperature with
Co2(CO)8 in THF leading to the dinuclear complex 10 in
good yield (74%). The IR spectra of 10 exhibits three
strong absorptions in the carbonyl region at 2028, 2054
and 2088 cmꢀ1 with spectral patterns similar to those
˚
Fig. 3. View of the crystal structure of 10. Selected bond lengths (A) and
angles (ꢁ): Co(1)–Co(2) 2.4800(9), C(17)–Co(2) 1.979(3), C(17)–Co(1)
2.014(2), C(18)–Co(1) 1.964(3), C(18)–Co(2) 1.974(3), C(19)–Co(1)
1.814(3), C(20)–Co(1) 1.829(3), C(21)–Co(1) 1.789(3), C(22)–Co(2)
1.837(3), C(23)–Co(2) 1.802(3), C(24)–Co(2) 1.809(4), C(17)–C(18)
1.339(4), Co(2)–C(17)–Co(1) 76.79(9), C(17)–C(18)–Co(1) 72.34(16),
C(17)–C(18)–Co(2) 70.42(17), Co(1)–C(18)–Co(2) 78.07(10), C(18)–
C(17)–C(15) 146.0(3).
manner according Scheme 3. The 31P spectrum of 11 exhib-
its two doublets of equal intensity at d 27.5 and 32.1 with
1J(Pt–P) couplings of 3447 and 3525 Hz, respectively. In
the IR spectrum, the C„C stretching vibration of free 5
1
observed for related cobalt-alkyne clusters [21]. In the H
NMR spectrum, the chemical shifts for the [2.2]PCP core
and C„CH are found to be very sensitive to cobalt com-
plexation on the adjacent alkyne bond. A significant down-
field shift is observed for the resonances of the [2.2]PCP
core and terminal protons in the metallatetrahedran by
ca. 0.10 and 3.15 ppm with respect to the free ligand, in
accordance with the reduction of the C„C triple-bond
character [23]. The 13C NMR resonances of the six carbo-
nyls appear as a single broadened signal at d 199.5, suggest-
ing that they are rapidly interchanging on the NMR time
scale. The molecular structure of 10 has been established
by X-ray diffraction (Fig. 3) and reveals a Co–Co bond
Ph3P
Pt
11
Ph3P
H
Pt(C2H4)(PPh3)2
toluene
- C2H4
˚
length of 2.4800(9) A, which is shorter than in Co2(CO)8
˚
(2.52 A) [22a]. The Co–C(alkyne) bonds distances span
˚
the range 1.964(3)–2.014(2) A, revealing a quite symmetric
dimetallatetrahedran core. The distance between the alkyne
carbons C(17) and C(18) amounts to 1.339(4) A and dis-
Co2(CO)8
THF
(OC)3Fe(μ-dppm)(μ-CO)Pt(PPh3)
toluene
- CO
˚
plays the expected elongation relative to an uncoordinated
-2 CO
5
˚
terminal C„C triple bond [1.20(2)–1.22(1) A]. Moreover,
Ph2P
PPh2
Pt
the angle C(18)–C(17)–C(15) of 146.0(3)ꢁ deviates signifi-
cantly from linearity. Compared to 3, the mean separation
of the ipso carbon atoms of the PCP moiety is somewhat
(CO)2Fe
O
PPh3
H
˚
shorter in 10 (2.804 vs. 2.783 A). Overall, the structural
H
(CO)3Co
Co(CO)3
parameters of the organometallic part are similar to those
described previously for other dicobalt complexes [21,22].
Reaction of 5 with [Pt(C2H4)(PPh3)2] in toluene at ambi-
ent temperature for 2 h affords [Pt(PCPAC„CH)(PPh3)2]
(11) as colorless powder, coordinated with 5 in a side-on
12
10
Scheme 3. Coordination of 5 on mono- and dinuclear complexes.

S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
843
at 2098 cmꢀ1 is replaced by a band occurring at 1687 cmꢀ1
,
documented. In the context of our research interest on the
chemistry of heterodinuclear systems towards organic
RNC ligands (insertion reactions, examination of the
bonding mode (bridging vs. terminal), transformation to
aminocarbyne ligands via electrophilic addition and photo-
physics) [30], we extended our study on PCP’s functional-
ized by triple bonds on the three-step synthesis (Scheme
4) and coordination chemistry of 4-isocyano[2,2]paracyclo-
phane (15).
the typical region expected for C@C stretching frequencies
of p-coordinated acetylenes bonded on a Pt(0) center [24].
The ability of 5 for carbon–carbon coupling reactions
was tested towards the heterodinuclear complex
[(OC)3Fe(l-dppm)(l-CO)Pt(PPh3)] [25a]. After heating a
toluene solution of this carbonyl-bridged compound with
an slight excess of 5, coupling of the l-CO ligand with
5 led to [(OC)2Fe{lAC(@O)C(PCP)@C(H)}(l-dppm)Pt-
(PPh3)] (12). The IR spectrum in the carbonyl region was
indicative of the presence of two terminal carbonyl ligands
and a ketonic carbonyl [m(C@O) 1686 cmꢀ1]. Furthermore,
all NMR data of this orange compound were consistent
with the formulation as dimetallacyclopentenone complex.
The 31P{1H} and proton NMR resonances and pat-
terns arising from 12 are quite similar to chemical shifts
and couplings reported by Shaw for related dimetalla-
cyclopentenone complexes [25a]. Our structural proposi-
tion is furthermore supported by the 195Pt{1H} NMR
spectrum. Fig. 4 shows a doublet of doublets of doublets
resonance centered at d ꢀ2823, stemming from the cou-
pling of the 195Pt-nucleus of 12 with the three phospho-
rus nuclei.
First racemic amine 13 was prepared by metallation of 4-
bromo[2.2]PCP with n-BuLi and successive amination of
the resulting 4-lithio derivative with MeLi/methoxyamine
according to a literature procedure [31]. The formamide
14 was obtained by refluxing 13 in ethyl formate as solvent.
1
The H and 13C{1H} NMR spectra of 14 reveals the pres-
ence of two conformers (cis and trans) due to a hindered
1
C–N rotation. In fact, the H NMR spectrum shows two
doublets at d = 7.75 and 8.41 assigned to C(@O)H and
C(@O)H0. The observed 13C NMR signals of 14 confirm
its proposed structure by the appearance of two distinct
methylene systems at d 32.4, 32.8, 33.7, 33.8 (C-1, C-2, C-
9, C-10) and d 34.9, 35.0, 35.2, 35.3 (C-10, C-20, C-90, C-
100). We also observed two signals for C-17 and C-170 at
d 158.4 and 163.8. The complete spectroscopic data, all cor-
roborating the given structural assignment of two confor-
mations, are gathered in Section 4. Finally, 14 was
transformed in 75% yield into the corresponding solid iso-
cyanide 15, using P(@O)Cl3 in the presence of NEt3. The
IR spectrum of 15 reveals a strong absorption at
2114 cmꢀ1, assigned to the m(C„N) stretching vibration.
In the 13C spectrum, the isocyanide-type carbon C-17
appears at d 164.5 ppm.
2.4. Synthesis of ( )-4-isocyano[2.2]paracyclophane (15)
Isocyanides are versatile reactives with an interesting
functional group, owing to their unusual reactivity, acting
as both nucleophiles and electrophiles in the course of a
reaction. Numerous applications of isocyanides in organic
synthesis [26,27], grafting as SAMs on substrate surfaces
[28] and in particular, coordination chemistry [29] are well
Fig. 4. 195Pt{1H} NMR spectrum of 12 (CDCl3 at 293 K, referenced towards K2PtCl4 in H2O).
H
C
H
N
N
NH2
HCOOEt
reflux
POCl3, THF, NEt3
O
0 C, 2h
˚
14
Scheme 4. Synthesis of 4- isocyano[2.2] paracyclophane.
13
15

844
S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
2.5. Coordination chemistry of 4-isocyano
[2,2]paracyclophane
substituted by CNR, giving exclusively the cationic com-
plex [ClPd(l-dppm)2Pt(C„Nxylyl)]Cl ligated by a terminal
isocyanide ligand [30g]. Surprisingly, treatment of 18 with
isocyanide 15 in a 1:1 ratio affords the A-frame compound
[ClPd(l-dppm)2(l-C@NAPCP)PtCl] (19), resulting from
formal insertion of 15 into the Pd–Pt bond. The bridging
bonding mode of the isocyanide ligand is deduced from
the IR spectrum, which exhibits a m(C@N) vibration at
1609 cmꢀ1. This frequency lies midway between those
reported for the homobimetallic A-frame compounds
We first examined the reactivity of 15 towards the hete-
rodimetallic complex [(OC)4Fe(l-dppm)PtCl2] (16), pos-
sessing
a
semi-bridging carbonyl ligand [25b].
Instantaneous opening of the dative iron ! platinum bond
occurred at ambient temperature upon addition of stoichi-
ometric amounts of ligand 15 to a CH2Cl2 solution of 16.
The resulting complex [(OC)4Fe{l-dppm}PtCl2(CN-
PCP)] (17) was isolated in high yields as a brownish solid.
It shows poor solubility in hexane or Et2O, but is very sol-
uble in THF or CH2Cl2. Both the IR and 31P{1H} spec-
trum indicate the breaking of the Fe–Pt bond. The
pattern and position of the four m(CO) stretching bands
at 2052, 1976, 1941 and 1931 cmꢀ1 is very similar to that
of [(OC)4Fe(g1-dppm)]. A strong m(C„N) vibration at
2204 cmꢀ1 is assigned to the terminally bound isocyanide
ligand on Pt. Due to the absence of a metal–metal bond,
[ClPd(l-dppm)2(l-C@N-p-tolyl)PdCl] (1627 cmꢀ1
)
)
and
[32].
[ClPt(l-dppm)2(l-C@N-p-tolyl)PtCl] (1531 cmꢀ1
Addition of a further equivalent of 15 to compound 19,
or addition of 2 equiv. of 15 to a CH2Cl2 solution of 18,
leads to the ionic A-frame compound [ClPd(l-dppm)2(l-
C@NAPCP)Pt(C„NAPCP)]Cl (20) in high yield (Scheme
5).
The coordination of 20 by both a bridging and a termi-
nal PCP–NC ligand follows from the IR spectrum, which
displays a m(C@N) vibration of medium intensity at 1611
and a second strong m(C„N) band at 2160 cmꢀ1. The
31P{1H} NMR spectra of 19 and 20 are very broad at
ambient temperature thus excluding a detailed analyses of
the AA0XX0 spin systems [33]. However, chemical shifts
2
the J(P–P) coupling of the two doublets found at d 24.9
(PFe) and 1.7 ppm (PPt) in the 31P{1H} NMR spectrum is
reduced to 20 Hz compared with the 51 Hz reported for
the precursor 16.
We have recently reported that upon addition of xylyliso-
cyanide to a CH2Cl2 solution of the d9–d9 system [ClPd(l-
dppm)2PtCl] (18), the Pt-bound chloro-ligand is rapidly
1
and J(Pt–P) couplings are in the expected range (see Sec-
tion 4) [30g]. Probably due to this broadness of the reso-
Ph2P
Fe
PPh2
Ph2P
PPh2
Pt
N
CO
Cl
Cl
C
15
OC
Pt
(OC)3Fe
Cl
CO
˚
CH2Cl2, 25 C
C
C
Cl
O
16
17
O
Ph2P
Cl
PPh2
Pt
15
Cl
Pd
˚
CH2Cl2, 25 C
C
N
Ph2P
PPh2
19
Ph2P
PPh2
Pt
Cl Pd
Ph2P
Cl
15
PPh2
18
15 (2 eq.)
Ph2P
Cl
PPh2
N
C
˚
CH2Cl2, 25 C
Pt
Pd
C
N
Ph2P
PPh2
Cl
20
Scheme 5. Coordination chemistry of isocyanide ligand 15.

S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
845
nances, we failed to obtain the 195P{1H} NMR spectra
despite long data acquisition periods. The preference for
the bridging bonding mode vs. terminal of ligand 15 in A-
frame compound 18 deserves some comments. Based on
the theoretical work of Howell [34a] and our empirical
observations on heterodinuclear Fe–Pt and W–Pt systems
[30b,30d,30e], it seems that essentially the p-acceptor pro-
pensity of a CNR ligand is decisive for the bonding mode.
Isocyanide ligands possessing a dominating r-donor char-
acter prefer a terminal bonding mode, whereas isocyanides
with sufficiently strong p-acceptor propensities may also
adopt a bridging bonding mode in heterodinuclear systems.
Note also that a given CNR ligand enhances markedly his
p-acceptor capability by strong bending of the angle CN–
R, whereas the r-donation is not much affected by the
bending [34a]. We therefore conclude that compared to
xylylisocyanide, PCP-isocyanide behaves as a somewhat
poorer r-donor and more powerful p-acceptor ligand
[34b]. We are aware that this hypothesis needs further
experimental verification.
(1H 300.13 MHz, 13C 75.48 MHz and 31P 121.49 MHz)
using the solvent as reference, except for the 31P NMR,
where the chemical shifts are relative to H3PO4 85% in
D2O. UV–Vis spectra were recorded on a Varian Cary 50
spectrophotometer, emission spectra on a Jobin-Yvon Flu-
orolog-3 spectrometer.
Electrochemical set-up. Analytical experiments were per-
formed in a three-compartment cell fitted with an AgNO3
(0.1 M in CH3CN)j Ag reference electrode, a glassy carbon
electrode (diameter 3 mm) and a platinum counter elec-
trode. The electrochemical apparatus was an Autolab
PGSTAT 20 Potentiostat Galvanostat (Ecochemie). The
solvent was spectroscopic grade CH2Cl2 with [NBu4][PF6]
(TBAF) as supporting electrolyte. Concentration of the
monomeric substrate was 2 · 10ꢀ3 M. Under these condi-
tions, the E1/2 of Cp2Fe+/0 was found to be 0.11 V
0.01 V vs. an Ag reference.
4.1. General procedure for the preparation of the dibromo
olefins 3 and 4
3. Conclusion
18
Br
Br
1
2
We have described an alternative route to synthesize in
high yield alkyne-substituted [2.2]paracyclophanes. These
[2.2]paracyclophanes derivatives may be modified with 2-
bromothiophene to afford a thiophene functionalized
alkyne or by double silylation to give an olefinic dithioether
using 1,1,2,2-tetramethyl-1,2-bis(diphenylthiomethyl)disi-
lane. Ligand PCPAC„CH (5) has also been coordinated
to various mono- and dinuclear complexes and used for a
carbon–carbon coupling reaction. Moreover, the isocya-
nide congeneer PCPAN„C (15) has been synthesized for
the first time and coordinated on different heterobimetallic
systems in a terminal and bridging bonding mode.
The emphasis of this present work was mainly an evalu-
ation of the synthetic potential of the unsaturated ligands 5
and 15 for organometallic chemistry. We investigate actu-
ally more in detail the electrochemical and photochemical
properties of all new compounds. In the light of the rich
redox properties and promising propensities of mononu-
clear and polynuclear transition metal acetylides
LnMAC„CAR for photophysical applications (even with
‘‘simple’’ R substituents) [35], we are currently extending
our project on the preparation of metal acetylides function-
alized with a [2.2]paracyclophane fragment.
14
3
13 8
17
15
16
4
5
7
12
6
11
10
9
PPh3 (2.40 g, 8.5 mmol), CBr4 (2.80 g, 8.5 mmol) and
zinc dust (0.55 g, 8.5 mmol) are placed in a Schlenk tube
and CH2Cl2 (25 mL) is added slowly. The mixture is stirred
at room temperature for 28 h. Then, 1 (1.00 g, 4.24 mmol),
dissolved in CH2Cl2 (10 mL), is added and stirring is con-
tinued for 2 h. The reaction mixture is extracted with three
50 mL portions of pentane. CH2Cl2 is added when the reac-
tion mixture became too viscous for further extractions.
The extracts are filtered and evaporated under reduced
pressure. Crystallization from pentane gave 1.578 g of 3
in 95% yield. m.p. 153–154 ꢁC. Anal. Calc. for C18H16-
Br2: C, 55.13; H, 4.11. Found: C, 55.35; H, 4.28%. 1H
NMR: d 2.95 (m, 7H, CH2), 3.24 (ddd, 1H, J1 = 9.4,
J2 = 7.0, J3 = 2.4 Hz, CH2), 6.45 (m, 7Haromat), 7.31 (s,
1H, CH@CBr2). 13C{1H} NMR: d 33.9, 34.7, 35.2, 35.5
(C-1, C-2, C-9, C-10), 90.1 (C-18), 130.2, 132.4, 133.2,
133.25, 133.3, 133.4, 135.0, 136.5 (C-5, C-7, C-8, C-12, C-
13, C-15, C-16, C-17), 135.6 (C-4), 138.4, 139.3, 139.6,
139.9 (C-3, C-6, C-11, C-14). UV–Vis (CH2Cl2) [kmaxnm
(e)]: 229 (15849 Mꢀ1 cmꢀ1), 289 (5623 Mꢀ1 cmꢀ1). Com-
pound 4 was obtained in a similar manner from 2 with
94% yield. m.p. 183 ꢁC. Anal. Calc. for C20H16Br4: C,
4. Experimental
General. All reactions were performed in Schlenk-tube
flasks under purified nitrogen. 4-Amino[2.2]PCP (13), 4-
formyl[2.2]PCP (1), 4,16-diformyl[2.2]PCP (2), and
[Pt(C2H4)(PPh3)2] were prepared according to a literature
procedure [31,36]. All solvents were predried and distilled
from appropriate drying agents. IR spectra have been
recorded on a Nicolet Nexus 470 spectrometer. All NMR
spectra were recorded in CDCl3 on a Bruker Avance 300
1
41.71; H, 2.80. Found: C, 41.63; H, 2.71%. H NMR: d
3.00 (m, 7H, CH2), 3.24 (m, 1H, CH2), 6.43 (d, 2H,
J = 8.2 Hz, Haromat), 6.59 (d, 2H, J = 2.1 Hz, Haromat),

846
S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
6.65 (dd, 2H, J = 8.2, J = 2.1 Hz, Haromat), 7.43 (s, 2H,
CH@CBr2). 13C{1H} NMR: d 34.9, 35.4 (C-1, C-2, C-9,
C-10), 90.5 (C-18, C-20), 130.5, 134.0, 135.7, 135.8 (C-5,
C-7, C-8, C-12, C-13, C-15, C-16, C-17), 136.2 (C-4,
C-16), 138.1, 139.3 (C-3, C-6, C-11, C-14). UV–Vis
(CH2Cl2) [kmax nm (e)]: 229 (57600 Mꢀ1 cmꢀ1), 266
(20500 Mꢀ1 cmꢀ1).
4.4. Preparation of Z-PhSCH2Me2SiC(H)@C(PCP)
SiMe2CH2SPh (9)
25
24
23
26
27
22
S
20
19
21
28
4.2. Conversion of dibromoolefins 3 and 4 to 5 and 6
35
33
Si
36
29
1
2
3
17
14
18
13 8
12 7
S
34
Si
15
16
31
32
4
5
A solution of 3.5 mmol of 3 in 25 mL of dry THF is
cooled to ꢀ78 ꢁC. 7.0 mmol of n-BuLi (2.5 M,) is added
dropwise to the cold solution. After cooling 1 h at
ꢀ78 ꢁC, the mixture is allowed to warm to room tem-
perature and stirring is continued one additional hour.
The mixture is poured into water and extracted with
CH2Cl2. The organic layer is dried over Na2SO4 and
evaporated under reduced pressure. The residue is then
purified by column chromatography on silica gel with
CH2Cl2/petroleum ether (v/v = 1:4) as eluent to give 5
(91% yield). 6 is obtained in a similar manner from 4
in 90% yield.
30
11
10
6
9
To a toluene solution (10 mL) containing 1,1,2,2-tetra-
methyl-1,2-bis(diphenylthiomethyl)disilane (181 mg,
0.5 mmol), 5 (100 mg, 0.43 mmol) and palladium acetate
(4 mg, 0.019 mmol) was added 1,1,3,3-tetramethylbutyl
isocyanide (12 mg, 0.084 mmol). The yellow mixture turned
quickly to red after heating to 110 ꢁC. Agitation was con-
tinued for 20 h, then all volatiles were removed under
reduce pressure. The residue is purified by column chroma-
tography on silica gel with petroleum ether/CH2Cl2 (v/
v = 4:1) as eluent and afforded 171 mg (67% yield) of 9 as
a yellow waxy solid. Anal. Calc. for C36H42S2Si2: C,
72.67; H, 7.11; S, 10.78. Found: C, 72.86; H, 7.34; S,
10.52%. 1H NMR: d 0.25 (s, 3H, SiCH3), 0.30 (s, 3H,
SiCH3), 0.54 (s, 3H, SiCH3), 0.59 (s, 3H, SiCH3), 1.93 (d,
1H, SiCH2, J1 = 12.1 Hz), 2.04 (d, 1H, SiCH2,
J1 = 12.1 Hz), 2.52 (s, 2H, SiCH2), 3.10 (m, 7H, CH2),
3.60 (m, 1H, CH2), 6.20 (s, 1H, C@CH), 6.60–7.20 (m,
17Haromat). 13C{1H} NMR: d ꢀ0.80, ꢀ0.72, ꢀ0.54, ꢀ0.44
(C-19, C-20, C-28, C-29), 18.4, 18.5 (C-21, C-30), 35.35,
35.25, 35.15, 34.4 (C-1, C-2, C-9, C-10), 124.5, 124.8,
125.8, 126.0, 126.2, 126.5, 128.4, 128.6, 128.7, 129.8,
129.9, 132.1, 132.2, 132.5, 133.0, 134.2, 135.3 (C-5, C-7,
C-8, C-12, C-13, C-15, C-16, C-23, C-24, C-25, C-26, C-
27, C-32, C-33, C-34, C-35, C-36), 139.3, 139.4, 139.5 ,
139.7, 139.9, 140.1, 145.4 (C-3, C-4, C-6, C-11, C-14, C-
22, C-31), 146.4 (C-18), 164.5 (C-17). 29Si{1H} NMR:
ꢀ6.53 (s), ꢀ9.94 (s). UV–Vis (hexane) [kmax nm (e)]: 228
4.3. Sonogashira coupling of 5 with 3-bromothiophene
6'
2
S
1
2'
5'
1'
3
6
14
11
13
12
8
7
3'
4'
15
16
4
5
9
10
Diethylamine (20 mL), 5 (232 mg, 1 mmol), CuI (5 mg,
0.026 mmol), 2-bromothiophene (163 mg, 1 mmol) and
PdCl2(PPh3)2 (15 mg, 0.021 mmol) are placed in a flask.
The mixture is first degassed, then purged with Ar and
heated to 50 ꢁC for 48 h. Then the mixture is poured into
water and extracted with CH2Cl2. The extract is dried
over Na2SO4 and evaporated under reduced pressure.
The residue is purified by column chromatography on sil-
ica gel with petroleum ether/CH2Cl2 (v/v = 3:7) as eluent
affording 267 mg (85% yield) of 8 as a pale yellow pow-
der. Anal. Calc. for C23H22S: C, 83.59; H, 6.70; S, 9.70.
Found: C, 83.45; H, 6.62; S, 9.65%. IR (KBr): 2192(w)
(13600 Mꢀ1 cmꢀ1),
(4600 Mꢀ1 cmꢀ1).
258
(8500 Mꢀ1 cmꢀ1),
286
cmꢀ1
.
1H NMR: d 3.10 (m, 7H, CH2), 3.60 (m, 1H,
4.5. Preparation of [Co2(CO)6(l-g2-PCP–CCH)] (10)
CH2), 6.55 (m, 7H, H-60, H-5, H-7, H-12, H-13, H-15,
H-16), 7.00 (d, 1H, J = 7.6 Hz, H-8), 7.10 (dd, 1H,
J = 4.1, J = 4.7 Hz, H-50), 7.35 (d, 1H, J = 4.1 Hz, H-
40). 13C{1H} NMR: d 34.3, 34.5, 35.1, 35.4 (C-1, C-2,
C-9, C-10), 85.9 (C-10), 93.4 (C-20), 123.8 (C-30), 124.4
(C-4), 127.0, 127.2, 130.1, 131.4, 132.4, 132.7, 132.9,
133.3, 133.9 (C-40, C-50, C-60, C-7, C-8, C-12, C-13, C-
15, C-16), 136.7 (C-5), 139.3, 139.5, 139.7 (C-6, C-11,
C-14), 142.4 (C-3). UV–Vis (CH2Cl2) [kmax nm (e)]: 229
(46800 Mꢀ1 cmꢀ1), 319 (12900 Mꢀ1 cmꢀ1).
Compound 5 (116 mg, 0.5 mmol) is added in small por-
tions to a THF solution (7 mL) of dicobalt octacarbonyl
(171 mg, 0.5 mmol). The mixture is stirred for 2 h at room
temperature. The solvent is removed under vacuum and the
dark residue extracted with hot hexane. After several days
at 5ꢁC, 10 is isolated from the hexane extract in the form of
dark crystals (192 mg, 74% yield). Anal. Calc. for
C24H16Co2O6: C, 55.62; H, 3.11. Found: C, 55.48; H,
3.09%. IR (KBr): m(C„O) 2088(vs), 2054(vs), 2028(vs).

S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
847
1H NMR: d 3.10 (m, 7H, CH2), 3.30 (m, 1H, CH2), 6.35
(d, 1H, J = 7.6 Hz, Haromatic), 6.40 (d, 1H, J = 7.6 Hz,
mixture was chromatographed on silica gel with CH2Cl2
as eluent. Yield: 83%. m.p. 195–196 ꢁC. Anal. Calc. for
C17H16NO: C, 81.57; H, 6.44. Found: C, 81.45; H,
H
aromatic), 6.45 (s, 1H, Hacetylenic), 6.50 (s, 1H, Haromatic),
6.55 (s, 1H, Haromatic), 6.65 (s, 3H, Haromatic). 13C{1H}
NMR: d 34.3, 35.1 (X2), 35.3, (C-1, C-2, C-9, C-10), 75.9
(C-18), 90.7 (C-17), 130.0, 132.4, 132.7, 132.9, 133.3,
135.1, 135.7, (C-5, C-7, C-8, C-12, C-13, C-15, C-16),
136.2 (C-4), 137.5 (C-6), 139.3, 139.6 (C-11, C-14), 140.7
(C-3), 199.6 (C-19-24). UV–Vis (CH2Cl2) [kmax nm (loge)]:
229 (18700 Mꢀ1 cmꢀ1), 318 (17000 Mꢀ1 cmꢀ1).
6.28%. IR (CH2Cl2): 3238 (mN–H), 1693 (mC@O) cmꢀ1
.
1H NMR: 2.72–2.79 (m, 1H, CH2), 2.88–3.1 (m, 6H,
CH2), 3.2–3.26 (m, 1H, CH2), 6.01 (s, 1H, NH), 6.35–
6.53 (m, 6Haromatic +NH0), 6.75 (dd, J1 = 1.3,
J2 = 5.9 Hz), 7.75 (d, 1H, C(@O)H, J3 = 7.1 Hz), 8.41 (d,
1H, C(@O)H0, J4 = 8.6 Hz) 13C{1H} NMR: d 32.4, 32.8,
33.7, 33.8 (C-1, C-2, C-9, C-10) , 34.9, 35.0, 35.2, 35.3
(C-10,C-20, C-30, C-40), 125.0, 126.8, 128.0, 128.2, 129.4,
129.5, 130.3, 130.8, 131.7, 132.3, 133.2, 133.3, 133.6,
135.2, 135.4, 135.7, 136.0, 138.6, 139.2, 139.3, 139.5,
141.4, 141.8 (C-5, C-50, C-7, C-70, C-8, C-80, C-12, C-120,
C-13, C-130, C-15, C-150, C-16, C-160, C-3, C-30, C-4,
C-40, C-6, C-60, C-11, C-110, C-14 , C-140), 158.4 (C-17),
163.8 (C-170). UV–Vis (CH2Cl2) [kmax nm (e)]: 229
(2290 Mꢀ1 cmꢀ1), 273 (5300 Mꢀ1 cmꢀ1).
4.6. Preparation of [Pt(PPh3)2(PCPACCH)] (11)
Compound 5 (116 mg, 0.3 mmol) was dissolved in tolu-
ene (3 mL) and [Pt(C2H4)(PPh3)2] (224 mg, 0.3 mmol) was
added. A gas was evolved and the mixture was stirred at
room temperature for 2–3 h. The resulting solution was
concentrated and the product was precipitated with ether
petroleum and dried under vacuum. Yield: 68%. Anal.
Calc. for C54H46P2Pt: C, 68.14; H, 4.84. Found: C, 68.18;
4.9. Preparation of 4-isocyano[2.2]paracyclophane (15)
1
H, 4.89%. IR (CH2Cl2): 1687 (mC„C) cmꢀ1. H NMR: d
2.65–3.31 (m, 8H, CH2), 5.99 (d, 1Haromat, J1 = 7.5 Hz),
17
C
1
2
6.17 (d, 1Haromat
,
J2 = 7.7 Hz), 6.32 (d, 1Haromat
,
,
J2 = 7.7 Hz), 6.51 (m, 3Haromat), 6.78 (d, 1Haromat
14
3
15 8
N
J1 = 7.5 Hz), 7.06–7.52 (m, 30H, Ph). 31P{1H} NMR: d
13
12
4
5
2
1
2
27.5 (d, J(P–P) = 37, J(Pt–P) = 3447 Hz), 32.1 (d, J(P–
1
7
16
6
11
10
P) = 37, J(Pt–P) = 3525 Hz).
9
4.7. Preparation of [(OC)2Fe{l-C(@O)C(PCP)CH}
(l-dppm)Pt(PPh3)] (12)
To a solution of 14 (251 mg, 1 mmol) and NEt3 (696 lL,
5 mmol) in THF (4 mL) was added at 0 ꢁC dropwise over
10 min O@PCl3 (102 lL, 1.1 mmol) in THF (1 mL). The
reaction mixture was stirred for 2 h at 0 ꢁC and then
poured into water. After extracted with ethyl acetate, the
organic layer was dried over anhydrous Na2SO4, filtered
and concentrated under reduced pressure. Chromatogra-
phy on silica gel with CH2Cl2/petroleum ether (v/v = 1:1)
as eluent gave 15 in form of a brownish powder. Yield:
75%. m.p. 133–134 ꢁC. Anal. Calc. for C17H15N: C,
87.52; H, 6.48; N, 6.00. Found: C, 87.42; H, 6.38; N,
5.92%. IR (KBr): 1436, 1501, 1594, 2114 (mN„C), 2854,
To a solution of [(OC)3Fe(l-dppm)(l-CO)Pt(PPh3)]
(151 mg, 0.15 mmol) in toluene, 1.5 equiv. of 5 (53 mg)
were added. After stirring for 2–3 h at 60 ꢁC, all volatiles
were removed in vacuo, the orange residue washed with
hexane and dried in vacuo. Yield: 142 mg (78%). Anal.
Calc. for C64H53FeO3P3Pt: C, 63.32; H, 4.40. Found: C,
63.22; H, 4.38%. IR (KBr): 1958(vs), 1910(vs) m(C„O),
1686 (s) (mC@O).31P{1H} NMR: d 9.5 (P2Pt), dd,2J(P2–P3,
2+3J(P2–P1) = 57 Hz), 32.0 (P3PPh3, dd, 2J(P2–P3) = 5,
3 + 4J(P1–P3) = 36 Hz), 62.7 (P1Fe, dd, 2J(P1-P3) = 36,
2+3J(P1–P2) = 57 Hz). 195Pt{1H} NMR: d ꢀ2823 (ddd,
2 + 3
1
1
2894, 2926, 3038 cmꢀ1
CH2), 6.36 (s, 1Haromat), 6.51 (m, 4Haromat), 6.62 (dd,
1Haromat J1 = 1.8, J2 = 7.9 Hz), 7.09 (dd, 1Haromat
.
1H NMR: d 2.85–3.28 (m, 8H,
J
= 137, J(Pt–P2) = 2738, J(Pt–P3) = 3446 Hz).
Pt–P1
4.8. Preparation of 4-formamido [2.2]paracyclophane (14)
,
,
J1 = 1.8, J2 = 7.9 Hz). 13C{1H} NMR: d 32.4 (C-1),
33.5(C-2), 34.8, 35.2 (C-9, C-10), 128.5 (C-4), 131.9 (C-
15), 132.4, 132.9 (C-7, C-12), 133.5 (C-13, C-16), 133.7,
134.7 (C-8), 135.0 (C-5), 136.8 (C-11), 139.2 (C-6,C-14),
141.5 (C-3), 164.5 (C-17). UV–Vis (CH2Cl2) [kmax nm (e)]:
229 (14200 Mꢀ1 cmꢀ1), 272 (2400 Mꢀ1 cmꢀ1).
1
2
H
14
3
H
15 8
17
N
13
12
4
5
O
7
16
6
11
10
9
4.10. Preparation of [(OC)4Fe{l-dppm}PtCl2(CN–PCP)]
(17)
Compound 13 (348 mg, 1.5 mmol) was dissolved in ethyl
formate and refluxed for 12 h, and then the excess ethyl for-
mate was removed under reduced pressure. The resulting
To a suspension of 16 (62 mg, 0.075 mmol) in CH2Cl2
(2 mL), the equivalent amount of 15 (17 mg, 0.075 mmol)

848
S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
Table 1
dissolved in 1 mL of CH2Cl2 was added over 5 min. The
resulting clear solution was stirred for a further 10 min,
then the solvent was removed affording 17 in almost quan-
titative yield. Anal. Calc. for C46H37Cl2FeNO4P2Pt Æ
CH2Cl2: C, 49.60; H, 3.43; N, 1.23. Found: C, 49.52; H,
3.38; N, 1.21%. IR (CH2Cl2): 2204 (s), m(C„N); 2052 (s),
Cristallographic and refinement data for 3 and 10
3
10
Formula
C18H16Br2
392.13
173(2)
Monoclinic
P21/c
16.8119(16)
8.1412(8)
11.1957(11)
105.340(2)
1477.8(2)
4
C24H16Co2O6
518.23
193(2)
Monoclinic
C2/c
20.385(5)
7.6128(12)
29.280(5)
108.59(2)
4306.9(14)
8
Formula weight (g molꢀ1
T (K)
)
Crystal system
1976 (s), 1941(vs), 1931(vs) m(CO) cmꢀ1 31P{1H} NMR:
.
Space group
d 1.70 (d, PPt, 2J(PPt–PFe) = 20, 1J(Pt–PPt) = 3319 Hz),
˚
a (A)
2
3
1
˚
24.88 (d, PFe, J(PPt–PFe) = 20, J(Pt–PFe) = 123 Hz). H
NMR: d 2.78–3.25 (m, 8H, CH2), 4.21 (m, 2H, CH2),
6.12–6.83 (m, 7Haromat), 7.43–7.96 (m, 20H, Ph).
b (A)
˚
c (A)
b (ꢁ)
3
˚
V (A )
Z
qcalc (mg mꢀ3
)
1.763
5.472
776
1.598
1.579
2096
4.11. General procedure for the preparation of the A-frame
compounds 19 and 20
l (mmꢀ1
F(000)
)
H Range (ꢁ)
Index ranges
1.6–26.04
ꢀ20 6 h 6 20,
ꢀ10 6 k 6 10,
ꢀ13 6 l 6 13
29779
2902 [0.0354]
2902/0/181
0.947 and ꢀ0.456
2.11–26.00
ꢀ25 6 h 6 25,
ꢀ9 6 k 6 9,
ꢀ35 6 l 6 35
30116
One equivalent (23 mg, 0.1 mmol) or two equivalent
(46 mg, 0.2 mmol) of 13, diluted in 2 mL of CH2Cl2, were
added within 30 min to a stirred solution of 18 (114 mg,
0.1 mmol) in 3 mL of CH2Cl2. The reddish solution was
stirred for 1 d and then evaporated to dryness. The orange
residue, obtained in almost quantitative yield, was washed
with 5 mL of Et2O and dried in vacuum.
Compound 19: Anal. Calc. for C67H59Cl2NP4-
PdPt Æ CH2Cl2: C, 55.89; H, 4.18; N, 0.96. Found: C,
55.87; H, 4.08; N, 0.95%. IR (KBr): 1609(m) cmꢀ1
m(C@N). 31P{1H} NMR: d 15.5 (m, unresolved, PPt,
1J(Pt–P) = 3523 Hz), 13.1 (m, unresolved, PPd). 1H
NMR: d 2.10–2.52 (m, 8H, CH2), 2.79 (m, 4H, PCH2P),
Collected reflections
Independent reflections [Rint
Data/restraints/parameters
]
4193 [0.0658]
4193/0/293
0.565 and
ꢀ0.882
Largest differencꢀe3s in peak
˚
and hole (e A
)
Final R indices [I > 2r(I)]
R1 = 0.0253,
wR2 = 0.0747
R1 = 0.0300,
wR2 = 0.0855
1.01
R1 = 0.0516,
wR2 = 0.1432
R1 = 0.0593,
wR2 = 0.1517
1.062
R indices (all data)
Goodness-of-fit on F2
5.62 (d, 1Haromat
, J1 = 7.9 Hz), 5.70 (d, 1Haromat,
J1 = 7.9 Hz), 6.01 (d, 1Haromat, J1 = 7.9 Hz), 6.09 (d,
1Haromat, J1 = 7.9 Hz), 6.28 (d, 1Haromat, J1 = 7.9 Hz),
6.33 (d, 1Haromat, J1 = 7.9 Hz), 6.36 (s, 1H), 7.01–8.3 (m,
40H, Ph). UV–Vis (CH2Cl2) [kmax nm (e)]: 228 (55920
employed using Sadabs version 2.01 (Bruker AXS, 1999).
All structures were solved applying direct and Fourier
methods, using SHELXS-90 (G.M. Sheldrick, University of
Go¨ttingen 1990) and SHELXL-97 (G.M. Sheldrick,
SHELXL97, University of Go¨ttingen 1997). Refinement of
the structures was carried out by full-matrix least-squares
methods based on F 2o (SHELXL-97). The non-hydrogen
atoms were refined with anisotropic thermal parameters
for all non-H atoms in the final cycles. All of the H-atoms
were placed in geometrically calculated positions and each
was assigned a fixed isotropic displacement parameter
based on a riding-model. All calculations were performed
using the WinGX crystallographic software package, using
the programs SHELXS-90 and SHELXL-97 [37].
M
ꢀ1 cmꢀ1), 273 (59630 Mꢀ1 cmꢀ1), 396 (4290 Mꢀ1 cmꢀ1).
Compound 20: Anal. Calc. for C84H74Cl2N2P4PdPt: C,
62.75; H, 4.64; N, 1.74. Found: C, 62.87; H, 4.68; N,
1.75%. IR (CH2Cl2): 1611(m) cmꢀ1 m(C@N), 2160 (s)
m(C„N) cmꢀ1 31P{1H} NMR: d 18.8 (m, unresolved,
;
1J(Pt–P) = 3740 Hz). 1H NMR: d 2.31 (m, br, 4H, PCH2P),
2.44–2.94 (m, 16H, CH2), 5.95 (s, 1Haromat), 6.23 (m, br,
4Haromat), 6.98–8.23 (m, 49H, Ph + Haromat). UV–Vis
(CH2Cl2) [kmax nm (e)]: 228 (62870 Mꢀ1 cmꢀ1), 273
ꢀ1
(31050
M
cmꢀ1), 395 (6620
M
ꢀ1 cmꢀ1), 468
(4250 Mꢀ1 cmꢀ1).
Acknowledgements
4.12. Crystal structure determinations
`
We are grateful to the French Ministere de la Recherche
Relevant crystallographic details are given in Table 1.
Measurements were carried out on a Stoe IPDS diffractom-
eter (10) and a Bruker APEX-CCD diffractometer (3). The
intensities of 10 were determined and corrected by the pro-
gram INTEGRATE in IPDS (Stoe & Cie, 1999). An empirical
absorption correction was employed using the FACEIT-pro-
gram in IPDS (Stoe & Cie, 1999). The intensities of 3 were
determined and corrected by the programs Smart version
5.622 (Bruker AXS, 2001) and SaintPlus version 6.02 (Bru-
ker AXS, 1999). An empirical absorption correction was
et Technologie for financial support and a PhD grant for
S.C.
Appendix A. Supplementary material
CCDC 298766 and 298767 contain the supplementary
crystallographic data for 3 and 10. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/
conts/retrieving.html, or from the Cambridge Crystallographic

S. Cle´ment et al. / Journal of Organometallic Chemistry 692 (2007) 839–850
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