Synthesis and basic coordination properties of side-chain functionalized bis-phosphonio-benzophospholides

Article abstract of DOI:10.1002/1521-3749(200106)627:6<1119::AID-ZAAC1119>3.0.CO;2-5

Salts containing bis-phosphonio-benzophospholide cations 2a-d with an additional donor site in one of the phosphonio-moieties were synthesized either via quaternisation of the Ph2P moiety in the neutral phosphonio-benzophospholide 3, or via ring-closure of the functionalized bisphosphonium ion 6. The Ph₂P-substituted cation 2d formed chelate complexes [M(κ²P,P′-2d)(CO)_n]⁺ with M(CO)_n = Ni(CO)₂, Fe(CO)₃, Cr(CO)₄. In the latter case, competition between formation of the chelate and a complex [Cr(κP-2d)₂(CO)₄]²⁺ was observed, and interpreted as a consequence of antagonism between the stabilizing chelate effect and destabilizing ligand-ligand repulsions. The formation of stable Pd^II and Pt^II complexes of 2 d suggests that the chelate effect may also overcome the kinetic inhibition which so far prevented isolation of complexes of these metals with bis-phosphonio-benzophospholides. The newly synthesized ligands and complexes were characterized by spectroscopic data, and an X-ray crystal structure analysis of 2a[Br]. The reactivity of chelate complexes towards Ph₃P indicates that the ring phosphorus atom is a weaker donor than the pendant Ph₂P-group. Wiley-VCH Verlag GmbH, 2001.

Full text of DOI:10.1002/1521-3749(200106)627:6<1119::AID-ZAAC1119>3.0.CO;2-5

ARTIKEL
Synthesis and Basic Coordination Properties of Side-chain Functionalized
Bis-phosphonio-benzophospholides
Dietrich Gudat*, Stefan HaÈp, Volker Bajorat, and Martin Nieger
Bonn, Institut fuÈr Anorganische Chemie der Rheinischen Friedrich-Wilhelms-UniversitaÈt
Received August 25th, 2000.
Dedicated to Professor Marianne Baudler on the Occasion of her 80th Birthday
Abstract. Salts containing bis-phosphonio-benzophospholide
cations 2 a±d with an additional donor site in one of the
phosphonio-moieties were synthesized either via quaternisa-
tion of the Ph2P moiety in the neutral phosphonio-benzo-
phospholide 3, or via ring-closure of the functionalized bis-
phosphonium ion 6.The Ph 2P-substituted cation 2 d formed
chelate complexes [M.k2P,P'-2 d).CO)n]+ with M.CO)n =
Ni.CO)2, Fe.CO)3, Cr.CO)4.In the latter case, competition
between formation of the chelate and a complex [Cr.kP-
2 d)2.CO)4]2+ was observed, and interpreted as a conse-
quence of antagonism between the stabilizing chelate effect
and destabilizing ligand±ligand repulsions.The formation of
stable PdII and PtII complexes of 2 d suggests that the che-
late effect may also overcome the kinetic inhibition which so
far prevented isolation of complexes of these metals with
bis-phosphonio-benzophospholides.The newly synthesized
ligands and complexes were characterized by spectroscopic
data, and an X-ray crystal structure analysis of 2 a[Br].The
reactivity of chelate complexes towards Ph3P indicates that
the ring phosphorus atom is a weaker donor than the pend-
ant Ph2P-group.
Keywords: Phosphorus heterocycles; Benzophospholides;
Chelates
Synthese und grundlegende Koordinationseigenschaften
seitenkettenfunktionalisierter Bis-phosphonio-benzophospholide
InhaltsuÈbersicht. Salze der Bis-phosphonio-benzophospholid-
Kationen 2 a±d, die uÈber eine zusaÈtzliche Koordinationsstelle
in einem der Phosphonio-Substituenten verfuÈgen, werden
entweder durch Quaternisierung der Ph2P-Gruppe des neu-
tralen Phosphonio-benzophospholids 3 oder uÈber Ring-
schluûreaktion aus dem funktionalisierten Bis-phospho-
niumion 6 dargestellt.Das Ph 2P-substituierte Kation 2 d
bildet Chelatkomplexe [M.k2P,P'-2 d).CO)n]+ mit M.CO)n =
Ni.CO)2, Fe.CO)3, Cr.CO)4.Im letzten Fall wurde eine
Konkurrenz zwischen der Chelatbildung und der Entstehung
eines Komplexes [Cr.kP-2 d)2.CO)4]2+ beobachtet und als
Ausdruck eines Antagonismus zwischen dem stabilisieren-
den Chelateffekt und destabilisierenden Ligand±Ligand Ab-
stoûungen interpretiert.Die Bildung stabiler Pd II- und PtII-
Komplexe von 2 d zeigt, daû durch den Chelateffekt auch
die kinetische Hemmung uÈberwunden werden kann, die
bisher die Darstellung von Bis-phosphonio-benzophospho-
lid-Komplexen mit diesen Metallen verhinderte.Die neu
synthetisierten Liganden und Komplexe werden spektrosko-
pisch und im Fall von 2 a[Br] durch eine Einkristallstruktur-
analyse charakterisiert.Die ReaktivitaÈt der Chelatkomplexe
gegenuÈber Ph3P gibt Hinweise, daû das Phosphoratom im
Ring ein schwaÈcherer Donor als die periphere Ph2P-Einheit
ist.
Introduction
ceptor ligands towards transition metals [1].Only re-
cently, this field gained new attention when it was
pointed out that low coordinate phosphorus com-
pounds in which the phosphorus atom is part of a mul-
tiple bond system may act as effective p-acceptor li-
gands via their energetically low lying p*-orbitals [2].
Because of these properties, transition metal com-
plexes containing r.P)-coordinated phosphinines
.phosphabenzenes) have been proven to be highly ef-
ficient hydroformylation catalysts [2 a, 3].
Phosphorus based ligands are of considerable impor-
tance because of their ability to act as r-donor/p-ac-
* Priv.Doz.Dr.Dietrich Gudat
Institut fuÈr Anorganische Chemie der UniversitaÈt Bonn,
Gerhard-Domagk-Str.1 ,
D-53121 Bonn,
Fax: +49.0)2 28 73 53 27
,
E-mail: dgudat@uni-bonn.de
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127 Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2001 0044±2313/01/6271119±1127 $ 17.50+.50/0 1119

D.Gudat, S.Ha Èp, V.Bajorat, M.Nieger
We have recently established that the bis-triphenyl-
phosphonio-benzophospholide cation 1 forms stable
complexes with univalent coinage metals [4].Coordi-
nation occurs via the lone-pair at the ring phosphorus
atom, and the bonding situation has been qualitatively
described as superposition of dative L ® M and retro-
pendant phosphonio groups.In order to assess the ac-
cessibility of the ring phosphorus atom for metal coor-
dination, the formation of chelate complexes of 2 d
.n = 2, D = PPh2) with metal carbonyl fragments
of varying steric requirements .Ni.CO)2, Fe.CO)3,
Cr.CO)4) was studied.Regarding the importance of
complexes of Pt and Pd in catalysis, reaction of 2 d
with [PtCl2.cod)] and [PdCl2.PhCN)2] were also in-
vestigated.
dative L ¬ M contributions.The latter implies for
1
some p-acceptor character which owes presumably to
inductive stabilization of the p*-orbitals by the phos-
phonio groups [5].Even though this quality should
make the cation 1 an interesting ligand for many ap-
plications, its use turned out to be severely restricted
owing to steric protection of the coordination site by
the bulky R3P substituents .I, Fig.1) which prevented
bonding to metals with coordination geometries other
than planar or linear [4, 5 b].Looking for a strategy to
circumvent this limitation, we became interested in
side-chain functionalized bis-phosphonio-benzophos-
pholides II with a further donor site in a peripheral
phosphonio moiety.Upon complex formation, these
species permit incorporation of one group R as active
ligand into the metal coordination sphere and turn
thus a former repulsive interaction between the metal
fragment and an ªinnocentº R3P group into an attrac-
tive interaction.Apart from thermodynamic stabiliza-
tion of the formed complexes by the chelate effect,
this approach should reduce the steric constraints in
the vicinity of the ring phosphorus atom and make the
ligand amenable to coordinate to metal fragments
with a larger structural variety.
Results and Discussion
Ligand Syntheses
The assembly of cations of type 2 was achieved fol-
lowing two different strategies.The first approach in-
volved quaternisation of the phosphino-substituent in
the mono-phosphonio benzophospholide 3 [6] by ap-
propriately functionalized alkyl bromides to afford
bis-phosphonio-benzophospholides 2 a, b[Br] with an
additional olefine or nitrile moiety, or by addition of
acrylic acid [7] to afford the zwitterion 2 c with a pen-
dant carboxylate group .scheme 2).A preliminary sur-
vey of the scope of this reaction [8] suggested that the
quaternisation route tolerates a wide range of spacer
units between the benzophospholide moiety and the
pendant donor and can thus give access to bidentate
ligands with a variety of bite angles.On the other
hand, the choice of donor functions is limited by the
tendency of x-functionalized alkyl halides with
strongly nucleophilic functional groups to undergo self
quaternisation.As a consequence, cations of type
2
with pendant amine, phosphine, or pyridine moieties
were unaccessible by this route.
Scheme 1
We report here on the syntheses of bis-phosphonio-
benzophospholides
groups .D = CH=CH2, CN, CO2 , PPh2) in one of the
2
featuring additional donor
±
Scheme 2 Synthesis of bis-phosphonio-benzophospholides
by quaternisation of 3.
In order to obtain phosphine-functionalized bis-phos-
phonio-benzophospholide ions which are particularly
appealing ligands we developed an alternative syn-
thetic strategy as outlined in scheme 3. a,a'-Dibromo-
ortho-xylene was first converted via two subsequent
quaternisation steps into the x-chloroethyl-substituted
bis-phosphonium salt 4[Br2].The pendant Ph P-group
was then introduced by reaction with three equiva-
lents of LiPPh2 and subsequent quenching of the
2
Fig. 1 Release of steric strain in complexes of bis-phospho-
nio-benzophospholide cations by side-chain functionalization
.schematic representation).
1120
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127

Synthesis and Basic Coordination Properties of Bis-phosphonio-benzophospholides
formed transient bis-ylide 5 with ethereal hydrogen
chloride to give the bis-phosphonium salt 6[Cl2].
Reaction of 6[Cl2] with Cl2SiMe2 and excess
NaN.SiMe3)2 yielded the silaheterocycle 7 whose me-
tathetis with PCl3 finally gave the target compound
2 d[Cl].Conversion into trifluoromethanesulfonate
.OTf) or BPh4 salts was easily possible by anion ex-
change with LiOTf or NaBPh4, respectively.
transient vinylphosphonium species which is con-
verted to the ylide 5 by addition of HPPh2 and final
deprotonation.A consequence arising from this spe-
cial reaction mechanism is the unfeasibility to vary the
length of the alkyl chain connecting the phosphorus
atoms of the phosphonio and phosphine moieties,
however, the nature of the pendant phosphine moiety
should easily be modified by employing other phos-
phanide reagents than LiPPh2.
Characterization of the salts 2 a, b, d[X] and the be-
tain 2 c was unequivocally achieved from analytical
and spectroscopic .NMR, FAB-MS) data and a single
crystal X-ray structure analysis of 2 a[Br].The 31P
NMR spectra of 2 a±c display ABX patterns with simi-
lar chemical shifts and coupling constants .see Ta-
ble 1) as in the cation 1.The 31P NMR spectrum of
2 d reveals an AMNX-type splitting.The signal of the
pendant Ph2P-group displays a chemical shift in the
typical range of alkyldiphenylphosphines .d31P = ±14
to ±30 [10]) and is split into a doublet by coupling
with the phosphorus atom of the adjacent phospho-
nio-group.The 1H and 13C spectra display no peculia-
rities apart from duplication of the signals with re-
spect to symmetrically substituted bis-phosphonio-
benzophospholide cations such as 1, and chemical
shifts and coupling patterns of all atoms in the fused
ring system are similar as there.
Scheme 3 Synthesis of 2 d[Cl] .Tms = Me3Si).
Formation of the cation 2 d was also observed when 6
was directly reacted with PCl3/NEt3 as originally re-
ported by Schmidpeter et al.for the synthesis of 1 [9],
but owing to decomposition during the aqueous work-
up procedure only impure products were isolated and
this protocol was therefore abandoned.By analogy to
known reactions of b-functionalized phosphonium
salts [7], the phosphination of the 2-chloroethyl-phos-
phonio moiety in 4 is thought to proceed via base
.LiPPh2) promoted dehydrochlorination to give first a
Crystals of 2 a[Br] are composed of discrete anions
and cations .Figure 2) which display no unusually
short contacts and contain two additional solvent mo-
lecules .CH2Cl2) per asymmetric unit.The presence
of two phosphonio-groups with different substitution
pattern in the cation introduces no measurable asym-
metric distortion of the fused ring system.All bond
Table 1 31P NMR data .in CDCl3 at 30 °C) of cations 2 a±d and metal complexes 8±14. PA, PM, PN, PX, PY denote nuclei of
AMNX, [AMNX]2, or AMNXY spin systems; Ddcoord = d.complex) ± d.2 d)
PA .Ddcoord
)
PM
PN
PX .Ddcoord
)
JPP and JPr,P [Hz]b)
2 a
2 b
2 c
2 d
8
236.8
235.2
237.5
234.1
234.4
16.5
16.1
16.7
17.4
15.9
14.6
13.9
15.7
16.2
15.9
16.0
16.4
17.6
19.7
18.8
20.7
±
JAM = 84.7, JAN = 91.9, JMN = 8. 1
±
JAM = 83.9, JAN = 92.0, JMN = 8. 2
±
JAM = 85.8, JAN = 92.2, JMN = 8. 3
±12.0
28.6
JAM = 83.8, JAN = 91.7, JNX = 44.6, JMN = 8. 1
JAM = 91.9, JAN = 82.5, JMN = 8.0, JNX = 54.2
JAM = 74.7, JAN = 75.1, JAX = 7.6, JNX = 10.1, JMN = 7.1, JMX = 1. 4
JAM = 68.7, JAN = 69.9, JAX = 84.6, JMN = 7.0, JNX = 4. 5 Hz
JAM = 65.0, JAN = 63.4, JAX = 26.8, JNM = 7.0, JNX = 12.5
9
224.8 .±9.3)
232.0 .±2.1)
237.8 .+3.7)
32.7 .+44.7)
71.9 .+83.9)
56.4 .+68.4)
10a)
11a)
12a)
234.2c)
16.0
16.0
17.5
17.1
67.3 .+79.3)
49.9
JAM = 91.6, JAN = 84.7, JAX = 2.2, JMN = 7.9, JNX = 38.2, JNX' = 0.4, JXX' = 26.0
JAM = 91.8, JAN = 83.2, JAX = 2.3, JMN = 7.9, JNX = 31.2, JMX = 0.7, JXX' = 31.7
233.8c)
13 a
13 b
173.7 .±60.3)
156.8 .±77.3)
14.7
14.7
16.6
16.7
27.4 .+39.4)
5.0 .+17.0)
JAM = 61.0, JAN = 58.8, JAX = 30.1, JMN = 4.9, JNX = 7. 9
JAM = 55.3, JAN = 56.4, JAX = 30.3, JMN = 4.5, JNX = 9.1, JPt,A = 4078,
JPt,X = 3281
14 bd)
15 a
234.6
156.8
234.1
16.3
15.9
15.8
17.4
16.9
17.1
9.3 .+21.3)
28.9 .+40.9)e)
11.3 .+23.3)e)
JAM = 91.7, JAN = 83.3, JMN = 8.3, JNX = 53.9, JXX' = 15.4, JPt,X = 3649
JAM = 91.3, JAN = 84.5, JMN = 8.0, JMX = 49.9, JXY = 4. 0 Hz
15 b
JAM = 92.5, JAN = 84.7, JNX = 55.2, JMN = 9.1, JXY = 16.8, 1JPt,X = 5100
a) in THF-d8; b) absolute values given for all couplings; c) two data sets correspond to cis/trans isomers; d) d195Pt = 114; e) d31P .PY) [PPh3] = 32.1 .15 a),
10.5 .JPt,Y = 5090 Hz) .15 b)
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127
1121

D.Gudat, S.Ha Èp, V.Bajorat, M.Nieger
pated to overcome this effect and make chelate com-
plexes readily available.
Addition of 2 d[X] .X = OTf, BPh4) at low tempera-
ture to a CH2Cl2 solution of excess Ni.CO)4 proceeded
smoothly with gas evolution and coordination of the
pendant phosphine moiety to give the complex 8[X]
which was identified by 31P NMR spectroscopy.At-
tempts to isolate the product by removal of solvents
and excess Ni.CO)4 in vacuo resulted in loss of a sec-
ond CO ligand and generation of the chelate complex
9[X].This compound was formed directly when the re-
action of 2 d[X] and Ni.CO)4 was carried out at 35 °C,
and was isolated after removal of volatiles and recrys-
tallization.The corresponding iron complex 10[X] was
likewise formed in a clean reaction from 2 d[X] and
[Fe.CO)3.cod)] in THF and isolated after precipitation
with ether. 31P NMR studies gave no evidence for the
occurrence of a similar intermediate as 8 in this case.
Fig. 2 Molecular structure of 2 a in the crystal, ORTEP
view thermal ellipsoids are at the 50% probability level, H
Ê
atoms omitted for clarity; selected bond distances/A:
P.1)±C.2) 1.739.3), P.1)±C.9) 1.740.3), C.2)±C.3) 1.441.4), C.2)±P.2)
1.745.3), C.3)±C.4) 1.412.4), C.3)±C.8) 1.427.4), C.4)±C.5) 1.372.4),
C.5)±C.6) 1.399.4), C.6)±C.7) 1.379.4), C.7)±C.8) 1.407.4), C.8)±C.9)
1.441.4), C.9)±P.3) 1.751.3).
distances and angles in the benzophospholide moiety
match those of other structurally characterized bis-
phosphonio-benzophospholides [4 a, 5].
Complexation properties of a phosphine-functionalized
bis-phosphonio-benzophospholide
In order to survey to which extent side-chain functio-
nalization in the cations 2 is successful in steric depro-
tection of the ring phosphorus atom, we carried out a
systematic study of the reactions of 2 d with Ni.CO)4,
[Fe.CO)3.cod)], and [Cr.CO)4.nbd)] .nbd = norbor-
nadiene; cod = cyclooctadiene).The substrates were
chosen to permit the formation of chelate complexes
[M.k2P,P '-2 d).CO)n] in which the steric demand of
the M.CO)n fragment increases continuously with the
change in metal coordination geometry from tetrahe-
dral .Ni) over trigonal-bipyramidal .Fe) to octahedral
.Cr).Further investigations of reactions of 2 d with
[PtCl2.cod)] and [PdCl2.PhCN)2] were stimulated by
the observation that the cation 1 failed likewise to
form complexes with Pd.II) or Pt.II) centers [5 b, 11].
Regarding that ligand substitution at square planar d8-
transition metal centers follows frequently an associa-
tive mechanism, we attribute this reluctance to kinetic
inhibition due to sterically induced destabilization of a
pentacoordinate transition state.Steric deprotection in
connection with possible ªpre-coordinationº of a me-
tal atom to the pendant Ph2P group in 2 d was antici-
Scheme 4 Complexation reactions of 2 d[X] .X = OTf,
BPh4; cod = cyclooctadiene, nbd = norbornadiene).
Treatment of 2 d[X] with [Cr.CO)4.nbd)] afforded in
contrast to the previous reactions a mixture of three
phosphorus containing complexes.Even if all attempts
to their separation by fractionating crystallization or
chromatography failed and thus no pure compounds
were isolated, one of the products was identified by
its characteristic 31P NMR spectrum .see below) as
the expected chelate 11[X].The 31P NMR signals of
the remaining complexes displayed [AMNX]2-type
patterns which suggested coordination of the Ph2P
moieties of two molecules of 2 d to the same metal
and were on this basis tentatively assigned as the cis-
1122
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127

Synthesis and Basic Coordination Properties of Bis-phosphonio-benzophospholides
Table 2 IR data .mCO, in CH2Cl2) of [M.2 d).CO)n] and
[M.CO)n.dppb)] .dppb = 1,4-bis-diphenylphosphino-butane)
and trans-isomers of 12[X2].The product ratio 11 : 12
varied depending on the reaction conditions, with the
formation of 11 .from 10 up to ca.56%) being favored
by the use of excess Cr.CO)4.nbd), higher reaction
temperatures, and lower reagent concentrations.
mCO [cm±1
]
9
1997, 1971
1995, 1937
[Ni.CO)2.dppb)]
Finally, reaction of 2 d[X] with equimolar
[PdCl2.PhCN)2] or [PtCl2.cod)] proceeded straightfor-
ward with quantitative conversion into the complexes
13 a, b[X].Performing the reactions under 31P NMR
spectroscopic control revealed the formation of the
Pt-complex 13 b to occur according to a two-step me-
chanism: rapid reaction of two cations 2 d with a mole-
cule of [PtCl2.cod)] first gave a transient complex 14 b
which then reacted slowly with a second equivalent of
the starting material to afford 13 b.
10
2002, 1942, 1913
1981, 1908, 1879
[Fe.CO)3.dppb)]
Ni.CO)2 and fac-Fe.CO)3-moieties, respectively.Com-
parison of the observed vibrational frequencies with
those of corresponding 1,4-bis-diphenylphosphino-bu-
tane .dppb) complexes [14] .Table 2) reveals an over-
all shift to higher wavenumbers which is consistent
with a slightly higher p-acceptor quality of 2 d as com-
pared to dppb.A more quantitative comparison of li-
gand properties .e.g. by analysis of Tolman para-
meters [15]), or comparison of p-acceptor-abilities for
the two electronically different donor centers was pre-
cluded by the unavailability of complexes featuring
coordination of 2 d exclusively via the ring phosphorus
atom.
In order to obtain still some information on the
properties of the two different donor centers in 2 d,
we studied ligand substitution reactions of 9 and 13 b
with one equivalent of Ph3P. 31P NMR spectra of the
reaction mixtures revealed that in both cases quantita-
tive displacement of the ring phosphorus atom and
formation of the complexes 15 a, b occurred.The mag-
All obtained metal complexes constituted light yel-
low to orange solids which were readily soluble in po-
lar aprotic organic solvents such as CH2Cl2 or
CH3CN, and insoluble in unpolar solvents .hexane, to-
luene).Complexes with zerovalent metals were mod-
erately stable towards air and moisture, whereas
13 a, b displayed an enhanced sensitivity towards hy-
drolysis which had been previously noted for some
complexes of 1 [4 a, 11].The constitution of all com-
plexes followed unequivocally from analytical and
spectroscopic data [12].The 31P NMR spectra of 8±11
and 13 a, b displayed AMNX-type patterns and those
of the bis-phosphine-complexes 12 and 14 b more
complicated [AMNX]2 patterns.Comparison of the
observed chemical shifts of all complexes with those
of free 2 d .Table 1) revealed small negative or posi-
tive coordination shifts .Ddcoord = d.complex) ± d.2 d))
for the resonance of the ring phosphorus atom in che-
late complexes, and positive coordination shifts for co-
ordinated phosphorus atoms of pendant Ph2P-moi-
eties.Attachment of both coordination centers to the
same metal in chelate complexes was indicated by ad-
2
nitude of JPMP in the square planar Pt-complex 15 b
suggested that the cis-arrangement of the two phos-
phine moieties was retained.Isolation of the formed
complexes was not attempted.The observed behavior
is consistent with earlier reports in which easy repla-
cement of coordinated phosphaalkenes by Ph3P had
been noted [16], and suggests that the bond from the
metal atom to the r2,k3-phosphorus atom is weaker
than that to a phosphine .r3,k3)-center.
2
ditional splittings due to JPMP couplings which were
absent in the spectra of both free 2 d and complexes 8,
12, 14 b containing non-chelating cationic ligands, and
3
a significantly reduced magnitude of JPP attributable
to the coupling of the two 31P nuclei in the PCCP
chain.The latter is attributable to the presence of a
second coupling path in a chelate complex which cor-
4
responds to a J interaction and is presumably of op-
posite sign than the 3J coupling through the ligand
2
backbone.Whereas the value of JPMP allows no clear
Scheme 5 Reaction of bis-phosphonio-benzophospholide
chelate complexes with PPh3 .X = OTf, BPh4).
assignment of the cis- and trans-isomers of 12, both
2
1
the small magnitude of JPMP and the values of JPt,P
are indicative of a cis-arrangement of the two phos-
phorus ligands in 13 b and 14 b [13].The difference in
1JPt,P values in 13 b is consistent with a higher degree
of s-character in the Pt±P bond to the ring phosphorus
atom and reflects the different formal hybridisation
Conclusions
Two different synthetic routes to bis-phosphonio-ben-
zophospholide cations with an additional pendant do-
3
.sp2 vs.sp ) of the different donor atoms.
±
nor group .CN, C=C, CO2 ) in one of the phosphonio-
The IR spectra of the chelate complexes 9, 10 dis-
play the expected number of mCO vibrations for
moieties are described.It has been shown that this
side-chain functionalization allows the use of the
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127
1123

D.Gudat, S.Ha Èp, V.Bajorat, M.Nieger
d = 18.2 .d, JPC = 19.3 Hz, PCCH2), 20.5 .s, PCCCH2), 25.1 .dd,
JPC = 59.1, 7.4 Hz, PCH2), 109.0 .ddd, JPC = 96.6, 54.4, 13.8 Hz, C-1/3),
119,2 .s, CN), 120.7 .m, C-4/7), 121.1 .m, C-4/7), 121.4 .s, C-5/6), 121.4 .s,
C-5/6), 122.1 .dd, JPC = 85.6, 1.5 Hz, i-C.PPh2)), 122.6 .dd, JPC = 89.4,
1.9 Hz, i-C.PPh3)), 129.8 .d, JPC = 12.5 Hz, m-C.PPh3)), 129.9 .d,
JPC = 12.3 Hz, m-C.PPh2)), 133.3 .dd, JPC = 10.1 Hz, 0.5 Hz, o-C.PPh2)),
133.9 .d, JPC = 3.3 Hz, p-C.PPh2)), 133.9 .dd, JPC = 10.3 0.9 Hz,
o-C.PPh3)), 134.2 .d, JPC = 2,8 Hz, p-C.PPh3)), 144.2 .m, C-3 a/7 a), 144.2
.m, C-3 a/7 a).± FAB-MS: m/z .%): 646.100) [ 2 a+].
cations as chelating ligands and leads further to an im-
proved steric accessibility of the ring phosphorus
atom, permitting an unprecedented coordination to
metal carbonyl fragments with tetrahedral and trigo-
nal-bipyramidal coordinated metal centers.The for-
mation of a mixture of a chelate complex 11 and a
complex 12 in which two cations 2 d bind to the metal
exclusively via their phosphine-ends emphasizes the
limits of the sterically releasing effect: coordination of
the ring phosphorus atom to an octahedral metal cen-
ter seems still possible, but the sterically induced de-
stabilization offsets apparently the stabilization by the
chelate effect, rendering alternative reaction pathways
observable.The chelating coordination of the cation
2 d to square-planar d8-metal centers .PdII, PtII) sug-
gests that side-chain functionalization may likewise
overcome the kinetic inhibition of complexation .by
destabilization of pentacoordinate transition states)
which is an important finding regarding a potential
use of such complexes in catalysis.Finally, the inter-
mediates observed during the formation of the chelate
complexes 9, 13 b, as well as their further reactions
with Ph3P, reveal that the ring phosphorus atom is
more weakly bound than the phosphine moiety.The
reason for this effect is consistent with different
strengths of M±P bonds owing to the different hybridi-
sation of the two donor atoms.
[3-{.3-Butenyl)-diphenylphosphonio}-1-triphenylphosphonio-
benzo[c]phospholide] bromide .2 b[Br]): To a solution of 3
.290 mg, 0.50 mmol) in THF .5 ml) were added toluene
.15 ml) and 4-bromo-butene .140 mg, 1.00 mmol), and the
resulting mixture was stirred for 3 d.A light yellow precipi-
tate formed which was collected by filtration, washed with
toluene, and dried in vacuo.Yield: 300 mg .04.2 mmol,
84%), m.p. 219 °C.± Elemental analysis for C 42H36BrP3
.713.6): calcd. C 70.70 H 5.09; found C 71.7 H 5.2%.
1H NMR: d = 2.36 .m, 2 H, CH2), 3.11 .m, 2 H, CH2), 4.94 .m, 2 H,
=CH2), 5.74 .m, 1 H, =CH), 6.8±7.1 .m, 4 H, 4-H to 7-H), 7.5±7.8 .m,
25 H, C6H5).± 13C{1H} NMR: d = 26.5 .ddd, JPC = 57.2, 8.7, 4.0 Hz,
PCH2), 27.8 .dd, JPC = 5.3, 3.0 Hz, PCCH2), 109.0 .ddd, JPC = 92.9, 56.3,
13.0 Hz, C-1/3), 109.6 .ddd), JPC = 97.9, 54.7, 12.6 Hz, C-1/3), 117.3 .s,
=CH2), 120.9 .m, C-4/7), 121.6 .m, C-4/7), 121.8 .s, C-5/6), 121.8 .s, C-5/
6), 122.3 .d, JPC = 86.2 2.5 Hz, i-C.PPh2)), 123.4 .dd, JPC = 91.4, 2.5 Hz,
i-C.PPh3)), 130.3 .d, JPC = 12.5 Hz, m-C.PPh3)), 130.4 .d, JPC = 12.3 Hz,
m-C.PPh2)), 133.3 .d, JPC = 9.7 Hz, o-C.PPh2)), 134.3 .d, JPC = 10.1 Hz,
o-C.PPh3)), 134.5 .d, JPC = 2.8 Hz, p-C.PPh2)), 134.6 .d, JPC = 2.8 Hz,
p-C.PPh3)), 135.7 .d, JPC = 15.7 Hz, =CH), 144.5 .m, C-3 a/7 a), 144.5 .m,
C-3 a/7 a).± FAB-MS: m/z .%): 633.80) [ 2 b+], 649.100) [2 b+ + O].
[3-{.2-Carboxylatoethyl)-diphenylphosphonio}-1-triphenyl-
phosphonio-benzo[c]phospholide] 2 c: Acrylic acid .0.1 ml,
1.5 mmol) was added to a solution of 3 .200 mg, 0.35 mmol)
in 1 : 1 THF/ether .10 ml) and the mixture stirred for 12 h at
room temperature.The formed colorless precipitate was fil-
tered off, dissolved in CH2Cl2 .10 ml), and extracted with sa-
turated aqueous NaHCO3.The organic phase was separated
and dried over Na2SO4.Evaporation of the solvent and va-
cuum-drying produced 160 mg .70%) 2 c of m.p. 201 °C
.dec).± Elemental analysis for C 41H33O2P3 .650.6): calcd
C 75.69 H 5.11; found C 75.4 H 5.6%.
Experimental Section
General Remarks: All manipulations were carried out under
dry argon.Solvents were dried by standard procedures.
NMR spectra: Bruker AMX 300 .1H: 300.1 MHz, 31P
121.5 MHz, 13C: 75.4 MHz, 195Pt 64.2 MHz) in CDCl3 at
30 °C if not stated otherwise; chemical shifts referenced to
1
ext.TMS . H, 13C), 85% H3PO4 .N = 40.480747 MHz, 31P),
N = 21.4 MHz .195Pt); positive signs of chemical shifts denote
shifts to lower frequencies, coupling constants are given as
absolute values; prefixes i-, o-, m-, p- denote atoms of phenyl
substituents, and atoms in the benzophospholide ring are de-
noted as 4-C, 5-H, etc.MS: Kratos Concept 1 H, Xe-FAB,
1H NMR: d = 2.48 .m, 2 H, CH2), 3.43 .m, 2 H, CH2), 6.7±7.1 .m, 4 H, 4-H
to 7-H), 7.35±7.75 .m, 25 H, C6H5).± 13C{1H} NMR: d = 23.8 .dd,
JPC = 54.6, 6.9 Hz, PCH2), 31.0 .s, PCCH2), 108.0 .ddd, JPC = 96.5, 55.9,
14.2 Hz, C-1/3), 111.4 .ddd, JPC = 90.3, 56.1, 15.5 Hz, C-1/3), 121.0 .m,
C-4/7), 121.4 .m, C-4/7), 121.4 .s, C-5/6), 121.5 .s, C-5/6), 123.0 .dd,
JPC = 90.2, 2.9 Hz, i-C.PPh3)), 123.5 .dd, JPC = 85.4, 2.4 Hz, i-C.PPh2)),
129.9 .d, JPC = 12.0 Hz, i-C.PPh2)), 130.1 .d, JPC = 12.6 Hz, m-C.PPh3)),
133.3 .d, JPC = 9.9 Hz, o-C.PPh2)), 133.8 .d, JPC = 2.9 Hz, p-C.PPh2)),
134.0 .d, JPC = 16.8 Hz, CO2±), 134.2 .d, JPC = 10.1 Hz, o-C.PPh3)), 134.4
.d, JPC = 3.1 Hz, p-C.PPh3)), 144.5 .m, C-3 a/7 a), 144.5 .m, C-3 a/7 a). ±
FAB-MS: m/z .%): 651.100) [M+].
m-NBA matrix.± FT-IR spectra: Nicolet Magma 550, CaF
2
cells, in CH2Cl2 solution.Elemental analyses: Heraeus
CHNO-Rapid.Melting points were determined in sealed ca-
pillaries.The amount of co-crystallized solvents was verified
1
by integration of suitable H NMR signals. 31P NMR data of
cations 2 a±d and complexes 8±14 are given in table 1.
[1-{.2-Diphenylphosphinoethyl)-diphenylphosphonio}-3-
triphenylphosphonio-benzo[c]phospholide] tetraphenylborate
.2 d[BPh4]):
[3-{.3-Cyanopropyl)-diphenyl-phosphonio}-1-triphenylphos-
phonio-benzo[c]phospholide] bromide .2 a[Br]): To a solu-
tion of 3 .430 mg, 0.74 mmol) in 5 ml THF was added to-
luene .15 ml) and 4-bromobutyronitrile .150 mg, 1.00 mmol),
and the resulting mixture was stirred for 4 d at room tem-
perature.The product separated as light yellow precipitate
which was collected by filtration, washed with toluene, and
dried in vacuo.Yield 460 mg .06. 3 mmol, 85%), m.p.231 °C.
.a)
A mixture of a,a'-dibromo ortho-xylene .10 g,
38 mmol), Ph3P .9.9 g, 38 mmol), and toluene .150 ml) was
stirred for 24 hrs at room temperature.The formed colorless
precipitate was collected by filtration, washed twice with
20 ml of THF, and dried in vacuo to yield 12.4 g .62%)
of a-bromo-a'-triphenylphosphonio-ortho-xylene bromide
.31P{1H} .CH2Cl2): d = 21.2) which was employed for subse-
quent reactions without further purification.
±
Elemental Analysis for C42H35BrNP3 .726.6): calcd.
C 69.43 H 4.86 N 1.58; found C 69.36 H 5.24 N 1.65%.
.b)
A suspension of 2-chloroethyl-diphenylphosphine
1H NMR: d = 3.55 .m, 2 H, CH2), 2.01 .m, 2 H, CH2), 2.84 .m, 2 H, CH2),
6.81±7.12 .m, 4 H, 4-H to 7-H), 7.46±7.96 .m, 25 H, C6H5). 13C{1H} NMR:
.7.5 g, 30 mmol) and a-bromo-a'-triphenylphosphonio-ortho-
xylene bromide .12.4 g, 23.5 mmol) in CH3CN .300 ml) was
1124
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127

Synthesis and Basic Coordination Properties of Bis-phosphonio-benzophospholides
JPC = 17.3, 6.3 Hz, CH2), 23.9 .ddd, JPC = 56.0, 21.0 Hz, 6.8 Hz, CH2),
refluxed for 2 hrs and then stirred for further 24 hrs at ambi-
ent temperature.The formed colorless precipitate was col-
lected by filtration, washed three times with CH3CN .25 ml),
and dried in vacuo to give 10.9 g .14.1 mmol, 60%) of a-
.2-chloroethyl-diphenylphosphonio)-a'-triphenylphospho-
nio-ortho-xylene dibromide .4[Br2]) which was used without
further purification.± 31P{1H}: d = 26.8 .d, JPP = 4.5 Hz, > PPh2),
22.5 .d, JPP = 4.5 Hz, ±PPh3).
107.9 .ddd, JPC = 91.6, 56.2, 14.4 Hz, C-3), 110.1 .ddd, JPC = 96.6, 54.4,
13.8 Hz, C-1), 120.7 .m, C-7), 121.7 .m, C-4), 121.9 .s, C-6), 122.0 .s, C-5),
122.0 .d, JPC = 85.6 Hz, i-C.> PPh2)), 122.6 .d, JPC = 90.6 Hz, i-C.PPh3)),
129.2 .d, 2 JPC = 6.9 Hz, o-C.±PPh2)), 129.8 .s, p-C.±PPh2)), 130.3 .d,
JPC = 12.7 Hz, m-C.PPh3)), 130.5 .d, JPC = 12.4 Hz, m-C.> PPh2)), 132.8
.s, p-C.> PPh2)), 133.0 .s, p-C.PPh3))), 133.1 .s, m-C.±PPh2)), 134.3 .d,
JPC = 10.7 Hz, o-C.PPh3)), 134.7 .d, JPC = 10.3 Hz, o-C.> PPh2)), 136.3 .d,
JPC = 19.4 Hz, i-C.±PPh2)), 144.4 .m, C-7 a), 144.4 .m, C-3 a). ± FAB-MS:
m/z .%): 791.100) [2 d+].
.c) .4[Br2]) .10.4 g, 14.0 mmol) was added in four portions
within one hour to a solution of Ph2PLi .freshly prepared
from Ph2PH .8.7 g, 47 mmol) and n-BuLi .28.25 ml of 1.6 M
solution in hexane) in 150 ml of THF).The formed dark red
suspension was stirred for 5 hrs, ethereal HCl .ca.70 ml of
1 M solution) was added until the color disappeared, and
stirring of the mixture was continued for additional 10 hrs.
After the formed solids had been allowed to settle down and
the supernatant liquid carefully decanted, the residue was
treated with THF .150 ml) and stirred for further 10 hrs.The
formed precipitate was then filtered off, dissolved in CH2Cl2
.100 ml), and filtered again.The filtrate was concentrated in
vacuo to a total volume of 25 ml and treated with 25 ml of
warm THF.The mixture was then allowed to cool to room
temperature, another 200 ml of THF were added, and the re-
sulting suspension stirred for 12 hrs.The formed precipitate
was collected by filtration and dried in vacuo to give 9.8 g
.10.6 mmol, 79%) of a.2-diphenylphosphinoethyl-diphenyl-
phosphonio)-a'-triphenylphosphonio-ortho-xylene dibromide
6[Br2] of m.p. 180 °C.± 31P{1H}: d = 28.3 .dd, JPP = 3.8,
39.4 Hz, > PPh2), 22.3 .d, JPP = 3.8 Hz, ±PPh3), ±9.7 .d,
JPP = 39.4 Hz, ±PPh2).
.d) A mixture of 6[Br2] .45.8 g, 49.5 mmol) and NaN-
.SiMe3)2 .40.2 g, 219 mmol) in toluene .350 ml) was stirred
for 30 min at 0 °C and then for 90 min at room temperature.
The solution was cooled again to 0 °C, and a solution of
Me2SiCl2 .7.10 g, 55 mmol) in toluene .10 ml) added drop-
wise.The mixture was stirred for 24 hrs at ambient tempera-
ture, filtered, and the precipitate washed three times with
20 ml of toluene.An 31P NMR spectrum indicated formation
of the silaheterocycle 7 .d31P = 9.1 .dd, JPP = 45.1, 8.4 Hz,
JPSi = 26.2 Hz), 7.7 .d, JPP = 8.4 Hz, JPSi = 28.0 Hz), ±13.2 .d,
JPP = 45.1 Hz)). After cooling the combined filtrates to 0 °C
and addition of triethyl amine .50 ml), a solution of PCl3
.7.5 g, 55 mmol) in toluene .20 ml) was added dropwise with
stirring.After the addition was complete, the formed brown-
ish precipitate was allowed to settle down, the supernatant
liquid was carefully decanted, and CH2Cl2 .100 ml) was
added.After stirring the mixture for 2 hrs, all volatiles were
evaporated in vacuo.The residue was divided in two por-
tions each of which was dissolved in CH2Cl2 .70 ml) and
rapidly extracted three times with aequeous phosphate buf-
fer .50 ml of 0.25 M Na2HPO4/0.25 M KH2PO4, pH = 7).
The combined organic phases were dried over CaCl2 and
concentrated in vacuo to a volume of ca.40 ml.Addition of
THF .150 ml) lead to formation of a precipitate which was
collected by filtration and dried in vacuo to afford 20.5 g
.24.8 mmol, 50%) 2 d[Cl] of m.p. 209 °C.An analytically
pure sample of 2 d[BPh4] was obtained after stirring 2 d[Cl]
with an equimolar amount of NaBPh4 for 24 hrs in CH2Cl2,
filtration, and evaporation of the solvent.± Elemental Ana-
lysis for C76H63BP4 .1111.0): calcd. C 82.16, H 5.72, found
C 82.67 H 5.26%.
[Dicarbonyl-k2P,P'-{1-..2-9Diphenylphosphinoethyl)-diphe-
nylphosphonio)-3-triphenylphosphonio-benzo[c]phospho-
lide}nickel.0)] triflate 9[OTf]: A solution of 2 d[OTf] .5.0 g,
5.3 mmol) in CH2Cl2 .25 ml) was added dropwise at 35 °C to
a solution of Ni.CO)4 .1.8 g, 10.3 mmol) in CH2Cl2 .25 ml).
After the gas evolution .CO) was complete, stirring was con-
tinued for 1 hr, and the reaction mixture was then evapo-
rated to dryness.The residue was dissolved in THF .20 ml)
and left overnight at room temperature.The separated yel-
low crystals of 9[OTf] ´ 2 THF were filtered of, washed care-
fully with little cold THF, and dried in light vacuum.Yield
3.1 g .2.9 mmol, 55%), m. p. > 200 °C .dec).
1H NMR: d = 2.55 .m, 2 H, CH2), 3.38 .m, 2 H, CH2), 6.55±6.83 .m, 4 H,
4-H to 7-H), 7.20±7.35 .m, 10 H, C6H5), 7.48±7.58 .m, 10 H, C6H5), 7.60
.m, 3 H, C6H5), 7.63 .m, 4 H, C6H5), 7.75 .m, 15 H, C6H5), 7.86 .m, 6 H,
C6H5).± 13C{1H} NMR: 24.1 .ddd, JPC = 20.0, 4.2, 3.8 Hz, CH2), 25.0
.ddd, JPC = 58.0, 16.4, 1.8 Hz), CH2), 98.2 .dd, JPC = 103, 56 Hz, C-1/3),
98.4 .dd, JPC = 92, 51 Hz, C-1/3), 120.2 .q, JFC = 315.6 Hz, CF3), 120.3 .dd,
JPC = 4.2, 1.5 Hz, C-4/7), 120.9 .ddd, JPC = 4.6, 1.5, 0.8 Hz, C-4/7), 121.1 .s,
C-5/6), 121.2 .s, C-5/6), 122.3 .ddd, JPC = 87.3, 3.5, 1.5 Hz, i-C.> PPh2)),
123.8 .dd, JPC = 90.4, 2.7 Hz, i-C.±PPh3)), 129.5 .d, JPC = 9.6 Hz,
o-C.±PPh2)), 130.6 .d, JPC = 12.5 Hz, m-C.±PPh3)), 130.7 .d, JPC = 1.9 Hz,
p-C.±PPh2)), 130.8 .d, JPC = 12.6 Hz, m-C.> PPh2)), 132.7 .d, JPC
=
13.0 Hz, m-C.±PPh2)), 133.6 .d, JPC = 10.3 Hz, o-C.> PPh2)), 134.6 .d,
JPC = 3.0 Hz, p-C.> PPh2)), 134.8 .d, JPC = 3.0 Hz, p-C.±PPh3)), 135.3 .d,
JPC = 10.3 Hz, o-C.±PPh3)), 136.3 .dd, JPC = 31.6, 6.1 Hz, i-C.±PPh2)),
143.3 .ddd, JPC = 15.9, 7.2, 1.1 Hz, C-3 a/7 a), 144.3 .ddd, JPC = 14.9, 8.8,
1.1 Hz, C-3 a/7 a), 197.3 .dd, JPC = 3.5, 3.4 Hz, CO). ± IR .mCO): 1997,
1971 cm±1
.
[Tricarbonyl-k2P,P'-{1-..2-diphenylphosphinoethyl)-diphenyl-
phosphonio)-3-triphenylphosphonio-benzo[c]phospholide}-
iron.0)] tetraphenyl borate .10[BPh4]): 2 d[BPh4] .220 mg,
0.20 mmol) and [Fe.CO)3.cod)] .50 mg, 0.20 mmol) were
dissolved in THF .10 ml).The solution was stirred for 24 hrs,
reduced to 5 ml in vacuo, and 10 ml of Et2O were added.
The formed red precipitate was collected by filtration,
washed with Et2O, and dried in vacuo.Yield 200 mg
.0.16 mmol, 80%), m. p. 161 °C.± Elemental analysis for
C79H63BFeO3P4 ´ 2 THF .1395.1): calcd. C 74.90 H 5.71;
found C: 74.85; H: 5.75%.
1H NMR .THF-d8): d = 3.02 .m, 2 H, CH2), 3.42 .m, 2 H, CH2), 6.50±7.00
.m, 4 H, 4-H to 7-H), 7.18±8.05 .m, 55 H, C6H5).± 13C{1H} NMR .THF-
d8): 23.6 .d, JPC = 56.7 Hz, PCH2), 24.1 .d, JPC = 21.0 Hz, PCH2), 100.0
.dd, br, JPC = 37.5, 103.4 Hz, C-1, C-3), 119.0 .m, C-4/7), 120.2 .s, C-5/6),
120.6 .d, JPC = 1.3 Hz, C-4/7), 121.2 .s, C-5/6), 122.7 .dd, JPC = 90.1,
2.0 Hz, i-C.> PPh2)), 123.2 .dd, JPC = 86.6, 2.7 Hz, i-C.PPh3)), 128.9 .d,
JPC = 9.9 Hz, m-C.±PPh2)), 130.1 .d, JPC = 12.6 Hz, m-C.PPh3)), 130.5 .d,
JPC = 12.4 Hz, m-C.> PPh2)), 131.1 .s, p-C.±PPh2)), 132.6 .d, JPC = 9.7 Hz,
o-C.±PPh2)), 133.1 .d, JPC = 10.1 Hz, o-C.> PPh2)), 134.3 .d, JPC = 1.3 Hz,
p-C.> PPh2)), 134.5 .s, p-C.PPh3)), 134.9 .d, JPC = 10.3 Hz, o-C.PPh3)),
135.4 .d, JPC = 4.2 Hz, i-C.±PPh2)), 143.5 .m, C-3 a/C7 a), 143.5 .m, C-3 a/
7 a), 216.3 .d, JPC = 14.5 Hz, CO). ± FAB-MS: m/z .%): 931.2) [10+],
847.85) [10+ ±3 CO], 791.100) [2 d+].± IR . mCO): 2002, 1942, 1913 cm±1
.
Reaction of 2 d[BPh4] with [Cr.CO)4.nbd)]:
.a) A solution of 2 d[BPh4] .230 mg, 0.2 mmol) in THF
.10 ml) was added dropwise within 45 min to a warm .60 °C)
solution of [Cr.CO)4.nbd)] .100 mg, 0.4 mmol) in THF
.10 ml).Stirring was continued for 30 min.The mixture was
1H NMR: d = 2.17 .m, 2 H, CH2), 2.85 .m, 2 H, CH2), 6.79±6.93 .m, 4 H,
4-H to 7-H), 7.07±7.69 .m, 35 H, C6H5).± 13C{1H} NMR: d = 21.9 .dd,
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127
1125

D.Gudat, S.Ha Èp, V.Bajorat, M.Nieger
then allowed to cool to room temperature and concentrated
Table 3 Atomic coordinates . ´ 104) and equivalent isotro-
pic displacement parameters .A ´ 10 ) for 2 a[Br] .esd's in
parentheses; U.eq) is defined as one third of the trace of the
orthogonalized Uij tensor)
2
3
Ê
to 5 ml.Addition of Et O .10 ml) produced a red precipitate
2
which was filtered off, washed with Et2O, and dried in vacuo.
An 31P NMR spectrosocpic assay revealed the presence of a
mixture containing approx.56% of 11 and 44% of cis/trans-
12.Attempts to chromatographic separation of the mixture
x
y
z
U.eq)
allowed to recover
[Cr.CO)4.nbd)], but resulted in extensive decomposition of
the phosphorus containing complexes.
a
small amount of unreacted
Br.1)
P.1)
C.2)
C.3)
C.4)
C.5)
C.6)
C.7)
C.8)
6643.1)
3474.1)
2279.2)
1368.2)
288.2)
±464.2)
±171.3)
879.2)
1670.2)
2808.2)
2167.1)
3439.2)
3511.3)
4507.3)
5426.3)
5365.3)
4371.3)
1072.2)
1146.3)
325.3)
6786.1)
2215.1)
1447.2)
2015.2)
1662.2)
2335.2)
3374.2)
3747.2)
3077.2)
3296.2)
130.1)
±343.2)
±1179.2)
±1539.3)
±1062.3)
±228.3)
126.2)
±672.2)
±650.2)
±1232.3)
±1813.3)
±1828.3)
±1261.2)
±32.2)
1798.1)
2596.1)
2703.2)
2631.2)
2709.2)
2643.2)
2498.2)
2427.2)
2493.2)
2455.2)
2868.1)
2852.2)
2137.2)
2188.3)
2942.3)
3648.2)
3614.2)
1882.2)
876.2)
37.1)
16.1)
16.1)
15.1)
18.1)
19.1)
21.1)
19.1)
15.1)
16.1)
14.1)
16.1)
22.1)
27.1)
27.1)
25.1)
22.1)
16.1)
20.1)
25.1)
26.1)
27.1)
22.1)
19.1)
24.1)
33.1)
36.1)
37.1)
27.1)
14.1)
16.1)
21.1)
28.1)
29.1)
29.1)
22.1)
18.1)
32.1)
41.1)
37.1)
40.1)
32.1)
20.1)
24.1)
34.1)
42.1)
68.2)
60.1)
54.1)
99.1)
52.1)a)
86.1)a)
87.1)a)
52.1)b)
109.3)b)
98.3)b)
.b) 2 d[BPh4] .460 mg, 0.4 mmol) and [Cr.CO)4.nbd)]
.50 mg, 0.2 mmol) were dissolved in THF .10 ml). The solution
was stirred for 12 hrs and concentrated in vacuo to a total of
5 ml.Et 2O .10 ml) was slowly added.An orange precipitate
formed which was filtered off, washed with Et2O and dried in
vacuo.An 31P NMR spectroscopic assay revealed the presence
of a mixture of cis/trans-12 .88% by integration of suitable re-
sonances, data in Table 1) and 11 .10%) beside small amounts
of decomposition products which were not further identified.
Attempts to chromatographic separation of the mixture using
different stationary and mobile phases remained unsuccessful.
± IR .mCO): 2027, 1932, 1890 cm±1 .for 12).
C.9)
P.2)
C.10)
C.11)
C.12)
C.13)
C.14)
C.15)
C.16)
C.17)
C.18)
C.19)
C.20)
C.21)
C.22)
C.23)
C.24)
C.25)
C.26)
C.27)
P.3)
C.28)
C.29)
C.30)
C.31)
C.32)
C.33)
C.34)
C.35)
C.36)
C.37)
C.38)
C.39)
C.40)
C.41)
C.42)
C.43)
N.44)
C.1C)
Cl.1)
Cl.2)
C.2C)
Cl.3)
Cl.4)
C.3C)
Cl.5)
Cl.6)
84.2)
283.3)
±588.3)
±673.3)
156.3)
1273.3)
2077.2)
4090.2)
4767.2)
5728.3)
6002.3)
5329.3)
4370.3)
2383.1)
1420.2)
434.2)
[cis-Dichloro-k2P,P'-{1-..2-diphenylphosphinoethyl)-diphe-
nylphosphonio)-3-triphenylphosphonio-benzo[c]phospho-
lide}palladium.II)] triflate .13 a[OTf]): Addition of CH2Cl2
.15 ml) to a mixture of 2 d[OTf] .500 mg, 0.5 mmol) and
[PdCl2.PhCN)2] .200 mg, 0.5 mmol) immediately produced a
dark red solution which was stirred for 3 hrs, then layered
with 20 ml of THF, and stored at ambient temperature.An
orange-red crystalline precipitate of 13 a[OTf] formed slowly
which was collected by filtration, washed with THF, and
1907.2)
1860.3)
1710.3)
1617.3)
1666.3)
1821.3)
3500.1)
2658.2)
2288.2)
1568.3)
1209.3)
1559.3)
2298.3)
3759.2)
4508.3)
4647.4)
4036.3)
3315.3)
3174.3)
4827.2)
4822.3)
6007.3)
6649.3)
7116.4)
±1124.5)
24.1)
844.3)
721.3)
±271.3)
±1147.3)
±1037.3)
4537.1)
5110.2)
4540.2)
4922.3)
5865.3)
6420.3)
6058.2)
5436.2)
6365.3)
7086.3)
6887.3)
5954.4)
5222.3)
4446.2)
3853.3)
3837.3)
3406.4)
3103.5)
5910.4)
6283.1)
6485.2)
636.5)
±295.3)
±44.3)
918.3)
1659.2)
3554.2)
3721.3)
4603.3)
5304.3)
5149.3)
4274.3)
2123.2)
1083.2)
980.3)
1811.3)
2488.3)
3620.4)
3125.1)
4893.1)
±826.5)
489.1)
dried in vacuo.Yield 370 mg .03. mmol, 62%), mp. .160
.dec).
°C
1H NMR: d = 2.57 .m, 1 H, CH2), 3.10 .m, 2 H, CH2), 3.28 .m, 1 H, CH2),
6.40±6.68 .m, 4 H, 4-H to 7-H), 7.00±7.52 .m, 35 H, C6H5).± FAB-MS: m/z
.%): 987.30) [13 a+ +O], 949.80) [13 a+ +O ±Cl), 913 .100) [2 d+ +O +Pd].
[cis-Dichloro-k2P,P'-{1-..2-diphenylphosphinoethyl)-diphe-
nylphosphonio)-3-triphenylphosphonio-benzo[c]phospho-
lide}platinum.II)] tetraphenyl borate .13 b[BPh4]): THF
.10 ml) was added to 2 d[BPh4] .200 mg, 0.18 mmol) and
[PtCl2.cod)] .70 mg, 0.20 mmol). The mixture was stirred for
2 d, then layered with 5 ml of hexane, and stored at room
temperature.The formed yellow crystalline precipitate was
filtered off, washed with hexane, and dried in vacuo to afford
150 mg .0.11 mmol, yield 61%) of 13 b[BPh4], m.p. 168 °C.±
Elemental analysis for C76H63BCl2P4Pt .1377.0): calcd.
C 66.29 H 4.61; found C: 65.49; H: 4.80%.
±891.2)
3606.5)
4020.2)
2554.2)
3450.20)
3647.11)
2786.11)
929.2)
±422.2)
±641.16)
±1151.9)
421.9)
±1195.1)
±1370.14)
±229.8)
±1233.8)
a)
s.o.f.= 0.81.1); b) s.o.f.= 0.19.1)
1H NMR: d = 2.64 .m, 2 H, CH2), 2.85 .m, 1 H, CH2), 3.46 .m, 1 H, CH2),
6.60±6.87 .m, 4 H, 4-H to 7-H), 6.88±7.90 .m, 55 H, C6H5).± 195Pt NMR:
d = 411 .dd, JPt,P = 4078, 3281 Hz).± FAB-MS: m/z .%): 1075.100)
[13 b+ +OH], 1039.80) [13 b+ +OH, ±Cl], 1003.20) [2 d+ +OH +Pt].
[17 b]) with 495 parameters and 54 restraints, empirical ab-
sorption correction, H-atoms with a riding model, R1
.I > 2h.I)) = 0.062, wR2 = 0.196, Largest diff. peak and hole
Crystal structure determination of 2 a[Br] at 173.2) K: col-
ourless needles, C42H35BrNP3±2 CH2Cl2, M = 896.4, crystal
size 0.40 ´ 0.30 ´ 0.20 mm, triclinic, space group P1 .No.2):
±3
Ê
2.261 .near solvent) and ±1.240 e A .One of the solvent
molecules was disordered.Atomic coordinates and equiva-
lent isotropic displacement parameters are given in Table 3.
Crystallographic data .excluding structure factors) for the
structures reported in this work have been deposited with the
Cambridge Crystallographic Data Centre as supplementary
publication no.CCDC-148648.Copies of the data can be
obtained free of charge on application to The Director,
CCDC, 12 Union Road, Cambridge DB2 1EZ, UK .Fax:
int.code +.12 23)3 36-0 33; e-mail:teched@chemcrys.cam.ac.uk).
Ê
Ê
Ê
a = 12.6362.2) A, b = 12.9799.2) A, c = 13.6969.2) A, a =
3
Ê
97.238.1)°, b = 102.660.1)°, c = 97.748.1)°, V = 2143.60.6) A ,
Z = 2, q.calcd) = 1.389 Mg m±3, F.000) = 916, l = 1.35 mm±1,
63582 reflexes .2hmax = 56.6°) measured on a Nonius Kappa
CCD diffractometer at 123.2) K using MoKa radiation
Ê
.k = 0.71073 A), 10508 independent [Rint = 0.062] used for
structure solution .Direct Methods, SHELXS-97 [17 a]) and
refinement .full-matrix least-squares on F2, SHELXL-97
1126
Z.Anorg.Allg.Chem. 2001, 627, 1119±1127

Synthesis and Basic Coordination Properties of Bis-phosphonio-benzophospholides
Acknowledgment. This work was financially supported by
the Deutsche Forschungsgemeinschaft and the Fonds der
Chemischen Industrie.
[8] Similar cations as 2 a, b were formed in reactions of 3
with allyl bromide and x-cyanohexyl bromide; D.Gu-
dat, S.HaÈp, unpublished results.
[9] A.Schmidpeter, M.Thiele, Angew. Chem. 1991, 103,
333; Angew. Chem. Int. Ed. Engl. 1991, 30, 308.
[10] J.C.Tebby in: Phosphorus-31 NMR Spectroscopy in
Stereochemical Analysis .Eds:. J.G.Verkade, L.D.
Quin), VCH Publishers, Deerfield Beach, 1987, p.26 ff.
[11] D.Gudat, M.Nieger, M.Schrott, Inorg. Chem. 1997, 36,
1476.
[12] The molecular constitution of 9[BPh4] was also proven
by an X-ray crystal structure analysis; however, due to
the low diffracting power of the crystal and twinning
problems, the structure solution could not be satisfacto-
rily refined; N.Korber, V.Bajorat, D.Gudat, unpub-
lished results.
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[1] .a) H.Brunner, W.Zettelmeier, Handbook of Enantio-
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[14] dppb was chosen for comparison because the formed
chelate complexes have the same number of ring atoms
than those of 2 d.
[15] C.A.Tolman, Chem. Rev. 1977, 77, 313.
[16] R.Appel in Multiple Bonds and Low Coordination
Chemistry in Phosphorus Chemistry .Eds.: M. Regitz,
O.Scherer), Georg Thieme Verlag, Stuttgart, 1990,
191 f.
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Z.Anorg.Allg.Chem. 2001, 627, 1119±1127
1127