Triphos as a bidentate ligand: The reactivity of the dangling phosphorus in [PtMe2(triphos-P,P′)]

Article abstract of DOI:10.1016/S0020-1693(02)00773-9

Complex [PtMe₂(triphos-P,P′)], (1) where the linear triphosphine triphos [=bis(diphenylphosphinoethyl)phenylphosphine] acts as a bidentate ligand, can be easily converted in a variety of new complexes due to the reactivity of the free phosphorus donor. The selective oxidation of the uncoordinated phosphorus gave [PtMe₂(triphosPO-P,P′)] whose X-ray crystal structure is here reported; from the reactions of 1 with platinum and non platinum precursors homotrimetallic [Pt₃Me ₄XY(triphos)₂] (X=Y=Me, Cl, I, X=Me, Y=Cl) and heterotrimetallic ([Pt₂PdMe₄Cl₂(triphos) ₂] and [Pt₂RhMe₄(cod)(triphos) ₂]PF₆) complexes were obtained where triphos acts as a chelating/bridging ligand. When 1 was treated with triflic acid in the presence of a neutral electron donor L (L=SMe₂, pyridine, PPh₃), complexes [PtL(triphos)]²⁺ were rapidly recovered in high yields. The protonolysis of 1 in the presence of CO and methanol gave the new organometallic complex [Pt(COOMe)(triphos)]OTf.

Full text of DOI:10.1016/S0020-1693(02)00773-9

Inorganica Chimica Acta 333 (2002) 116ꢂ123
/
www.elsevier.com/locate/ica
Triphos as a bidentate ligand: the reactivity of the dangling
phosphorus in [PtMe2(triphos-P,P?)]
Giuliano Annibale a, Paola Bergamini b,*, Valerio Bertolasi b, Elena Besco b,
Michela Cattabriga a, Roberto Rossi b
a Dipartimento di Chimica, Universita` di Venezia, Calle Larga S. Marta, 2137, 31023 Venice, Italy
b Dipartimento di Chimica, Universita` di Ferrara, via L. Borsari 46, 44100 Ferrara, Italy
Received 6 November 2001; accepted 16 January 2002
Abstract
Complex [PtMe2(triphos-P,P?)], (1) where the linear triphosphine triphos [ꢀ
as a bidentate ligand, can be easily converted in a variety of new complexes due to the reactivity of the free phosphorus donor. The
/bis(diphenylphosphinoethyl)phenylphosphine] acts
selective oxidation of the uncoordinated phosphorus gave [PtMe2(triphosPO-P,P?)] whose X-ray crystal structure is here reported;
from the reactions of 1 with platinum and non platinum precursors homotrimetallic [Pt3Me4XY(triphos)2] (Xꢀ
/
Yꢀ
/
Me, Cl, I, Xꢀ
/
Me, YꢀCl) and heterotrimetallic ([Pt2PdMe4Cl2(triphos)2] and [Pt2RhMe4(cod)(triphos)2]PF6) complexes were obtained where
/
triphos acts as a chelating/bridging ligand. When 1 was treated with triflic acid in the presence of a neutral electron donor L (Lꢀ
/
SMe2, pyridine, PPh3), complexes [PtL(triphos)]2ꢁ were rapidly recovered in high yields. The protonolysis of 1 in the presence of
CO and methanol gave the new organometallic complex [Pt(COOMe)(triphos)]OTf. # 2002 Elsevier Science B.V. All rights
reserved.
Keywords: Platinum complexes; Triphosphine complexes; Polynuclear complexes
1. Introduction
trans influence of a variety of X ligands upon the central
metal bond and to establish a sequence of
nucleophilicity in the X ligand exchange reactions [4].
phosphorusÃ
/
The linear triphosphine PPh(CH2CH2PPh2)2 (triphos)
presents an extensive coordination chemistry with a
variety of metals mainly due to its ability to act as a
tridentate ligand both in an octahedral [1] and in a
square planar environment [2].
We have recently reported that when X is the easily
replaceable anion triflate (OTfꢃ ꢀCF3SO3ꢃ), complex
/
[PtOTf(triphos)]ꢁ can be regarded as a versatile synthon
to a variety of Ptꢂtriphos complexes [5].
/
During that work, we found that [PtOTf(triphos)]OTf
can be most conveniently prepared by treatment of
[PtMe2(triphos-P,P?)] with triflic acid.
Concerning Pt(II) chemistry, great emphasis has been
given to Pt(II)ꢂtriphos systems where the triphosphine
/
occupies three coordination positions while a mono-
dentate anionic or neutral ligand is bonded in the fourth
position (Fig. 1); these complexes represent excellent
probes for mechanistic studies of substitution reactions
at the metal, small molecule activation and catalytic
processes [3].
Complex [PtMe2(triphos-P,P?)], (1), is an example of
bidentate coordination of triphos, whose third phos-
phorus atom is dangling out the coordination plane.
The bidentate coordination mode of tridentate phos-
phines has been observed in a few complexes and it can
be accomplished in some different ways (Fig. 2): (i)
through two of the three equivalent phosphorus atoms
as in the tripodal phosphine 1,1,1-tris(diphenylpho-
sphinomethyl)ethane, giving a six membered ring [6];
(ii) through the two terminal phosphino groups as in
PPh(CH2PPh2)2, giving a six membered ring including
three phosphorus atoms [7]; (iii) through the central and
For example, [PtX(triphos)]ꢁ complexes (Xꢀ
mono-
/
dentate anionic ligand) have been used to probe the
* Corresponding author. Tel.: ꢁ39-532 291129; fax: ꢁ39-532
240709.
E-mail address: p.bergamini@unife.it (P. Bergamini).
0020-1693/02/$ - see front matter # 2002 Elsevier Science B.V. All rights reserved.
PII: S 0 0 2 0 - 1 6 9 3 ( 0 2 ) 0 0 7 7 3 - 9

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ð1Þ
Fig. 1. Pt-complexes with triphos acting as a tridentate ligand.
The 31P{1H} NMR of 2 shows the presence of three
inequivalent phosphorus atoms: PA appears as a doublet
with satellites at 48.6 ppm due to its coupling with PB
(2J(PBPA)ꢀ
a doublet of doublets with satellites at 49.0 ppm being
coupled with PA, with PC (3J(PCPB)ꢀ
53.2 Hz) and with
platinum (1J(PtPB)ꢀ
1803 Hz). These chemical shifts
/
4.5 Hz) and Pt (1J(PtPA)ꢀ
1810 Hz); PB is
/
/
/
are in the typical range of phosphorus atoms included in
a five membered chelate ring [11]. Finally, PC is a
Fig. 2. Some selected coordination modes of tridentate phosphines.
doublet (3J(PBPC)ꢀ
53.2 Hz) at 33.2 ppm, which is a
typical shift of a phosphine oxide [12].
/
one of the terminal phosphorus atoms giving a five
membered ring [8], like triphos in complex 1. This last
mode gives a particularly dynamic character to square
planar Pt(II) complexes for two reasons: (a) the length
of the pendant arm allows the uncoordinated phospho-
rus to reach the metal center; (b) the great tendency to
form two stable five membered chelate rings [9].
2
The coupling constant J(PBPA) is small compared
with 3J(PBPC) (4.5 vs. 53.2 Hz). This is due, as
previously noted in analogous situations [13], to the
two components of J(PP): BJ(PP) ‘coupling through the
backbone’ and MJ(PP) ‘coupling through the metal’.
The observed coupling constant is the algebraic sum of
BJ(PP) and MJ(PP): in the case of a five membered ring
BJ(PP) and MJ(PP) have often similar absolute values
but opposite signs and, therefore, the observed value is
smaller than the coupling J(PBPC) occurring only via the
backbone.
The preparation of 1, based on the substitution of cod
(codꢀ1,5-cyclooctadiene) with triphos in [PtMe2(cod)],
/
was first reported by Meek et al. in 1977 [10]. They also
described the fluxional behavior of 1 in solution, due to
the attack of the uncoordinated phosphorus on plati-
num leading to a fast exchange between the two external
phosphorus atoms of triphos via a five coordinated
intermediate, whose geometry is discussed also in a
recent paper by us [5b].
The recrystallization of crude 2 from CHCl3 and Et2O
gave crystals suitable for X-ray diffraction. Fig. 3 shows
the ORTEP view of 2. The two PtÃ
/
P bonds have similar
˚
lengths (2.263 and 2.256 A) and also the two PtÃ
/C
We reasoned that the presence in complex 1 of a free
phosphorus with a high tendency to coordinate should
be a powerful driving force to a variety of reactions.
We report here the selective oxidation of the uncoor-
dinated phosphorus and the X-ray crystal structure of
the oxidation product; the reactions of 1 with platinum
and non platinum precursors to form homotrimetallic
and heterotrimetallic complexes, respectively, where
triphos acts as a chelating/bridging ligand. Finally it
will be shown that the addition of L and triflic acid in
sequence can easily convert complex 1 into a variety of
[PtL(triphos)]2ꢁ complexes (Lꢀ
SMe2, pyridine, PPh3),
/
where triphos acts as a tridentate ligand.
2. Results and discussion
2.1. Oxidation of the uncoordinated phosphorus of
complex 1
Fig. 3. ORTEP [28] view of compound [PtMe2(triphosPO-P,P?)], 2.
Selected bond lengths and angles:
Pt1ÃP1ꢀ2.268(3);
Pt1ÃP2ꢀ2.258(3); Pt1ÃC1ꢀ2.11(1); Pt1ÃC2ꢀ2.09(1)
P1ÃPt1ÃP2ꢀ86.0(1); P1ÃPt1ÃC1ꢀ179.0(4); P1ÃPt1ÃC2ꢀ95.4(4);
P2ÃPt1ÃC1ꢀ93.1(4);
C2ꢀ85.4(5)8.
˚
A;
The treatment of 1 in benzene with aqueous H2O2
gives complex 2 where only the uncoordinated phos-
phorus is oxidized, Eq. (1).
P2ÃPt1ÃC2ꢀ177.5(5);
C1ÃPt1Ã

118
G. Annibale et al. / Inorganica Chimica Acta 333 (2002) 116ꢂ123
/
1
˚
bonds (2.11, 2.09 A). Pt and the four coordinated atoms
lie in a plane and the bond angles at Pt are very near to
908. The distance between O1 and P3 [Fig. 3, PC in Eq.
ii) the size of J(PtP) for PA, PB and PC (1801, 1797
and 1891 Hz, respectively) shows that all these three
atoms are directly bonded to platinum and trans to
a group of high trans influence like CH3;
˚
(1)] is 1.480 A; O1 points away from Pt and there are not
intramolecular interactions between PC and Pt.
This oxidation process creates a diphosphine-phos-
phine oxide ligand on platinum: this species has the
potentiality to act as a tridentate ligand exploiting the
iii) the P donors on the central platinum are cis to each
1
other as indicated by J(Pt(2)PC)ꢀ
/1891 Hz (com-
parable for example with the value of 1878 Hz in
cis-[PtMe2(PPh3)2] [14]).
coordination ability of PÄ
/
O particularly towards hard
The chiral centre at PB in 3 leads to the prediction of
two diastereoisomers (rac and meso) of 3 and these are
indeed observed in the 31P{1H} NMR spectra of 3 which
shows two sets of signals with the same multiplicity in
the ratio of 1:1.
The 31P{1H} NMR spectrum changes upon raising
the temperature. In DMSO at 20 8C, two sets of signals
are observed for PA PB and PC consistent with the
presence of rac and meso diastereomers. These two sets
of signals coalesce at higher temperatures and at above
100 8C, only one set of 31P{1H} NMR is observed (see
Section 3). The variable temperature experiment was run
also in toluene to exclude the involvement of the highly
coordinating solvent DMSO in the process and also in
this case a single set of signals was observed above
90 8C. This result is consistent with the interconversion
metal ions. The formation of the same ligand on
palladium has been recently reported by Sadler [12].
2.2. Coordination of the dangling phosphorus of complex
1. Formation of trinuclear complexes
2.2.1. The homotrimetallic complex [Pt3Me6(triphos)2],
(3)
The reaction between 1 and [PtMe2(cod)] in a 2:1 ratio
gives the trinuclear platinum complex 3 which can be
alternatively prepared from triphos and [PtMe2(cod)] in
a 2:3 ratio, Eqs. (2) and (3).
of the diastereoisomers by inversion at PB. The PtÃ
/PB
coupling undergoes small changes during the variable
temperature experiments (from 1790 Hz at 25 8C to
1763 Hz at 100 8C in toluene, from 1813 Hz at 25 8C to
1784 Hz at 140 8C in DMSO): this seems to indicate
that the process does not involve rupture of the PtÃ
/
PB
bond. Although the inversion at free phosphino phos-
phorus at high temperature has been observed long ago
[15], to our knowledge the inversion of configuration at
phosphorus belonging to a coordinated phosphine has
not previously been observed.
When 3 is treated with one equivalent of triphos, 1 is
recovered as the only product, Eq. (4).
2.2.2. Other homotrimetallic complexes
The reaction of 1 with [PtXY(cod)] (Xꢀ
/
Yꢀ
/
Cl; Xꢀ
/
Cl YꢀMe; XꢀYꢀI) gives the homotrimetallic com-
/
/
/
plexes [Pt3Me4Cl2(triphos)2], 4, [Pt3Me5Cl(triphos)2], 5,
and [Pt3Me4I2(triphos)2], 6 with chelating/bridging tri-
phos, Eq. (5).
ð4Þ
In this reaction the coordinated PC of complex 3, an
alkyldiarylphosphine, is replaced by the more nucleo-
philic PB of the free ligand (a dialkylarylphosphine); the
reaction is favored also by the formation of three chelate
rings (3 equiv. of 1) starting from two (1 equiv. of 3).
The identification of 3 is based mainly on 31P{1H}-
NMR observations:
i) from their high frequency chemical shifts, it can be
deduced that PA and PB (48.5 and 47.6 ppm,
respectively) are in a five membered ring while the
‘normal’ shift of PC (18.5 ppm) is consistent with a
monodentate coordination mode;
ð5Þ
In each case the product was obtained as a 1:1 couple
of rac and meso diastereoisomers.

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119
The coupling constant between PC and central Pt is
diagnostic for the stereochemistry around the central
platinum: 1J(PtPC) has a value of 3654 Hz in 4
indicating a cis geometry (compared with 3674 for cis-
[PtCl2(PPh3)2] [16]), while the values of 3070 in 5 and
2400 Hz in 6 support a trans geometry around central
platinum in these complexes (compare with 3144 Hz in
trans-[PtClMe(PPh3)2] [17] and 2477 Hz in trans-
[PtI2(PPh3)2], respectively [18]).
both the methyl groups on platinum (Scheme 1) which
can be promptly removed (step i and step ii in Scheme 1)
using strong coordinating acids like HOTf, p-TsOH and
CF3COOH.
We have previously shown that the product of the
reaction of 1 with triflic acid, complex [PtOTf(tripho-
s)]OTf, can be regarded as a versatile precursor to a
variety of [PtL(triphos)]2ꢁ obtainable via OTf substitu-
tion [5]. We then observed that the same products can be
obtained directly from 1 in a single step: in fact when the
protonolysis with HOTf is carried out in the presence of
a neutral electron donor L, the product recovered from
the process is [PtL(triphos)]2ꢁ, where triphos acts as a
tridentate ligand and L is bonded in the fourth position,
Eq. (8).
2.2.3. Formation of the heterotrimetallic complexes
[Pt2PdMe4Cl2(triphos)2], (7) and
[Pt2RhMe4(cod)(triphos)2]PF6, (8)
The reaction between 1 and [PdCl2(cod)] gives the
heterotrimetallic complex 7, [Pt2PdMe4Cl2(triphos)2] as
a 1:1 pair of diastereoisomers, Eq. (6).
ð8Þ
In Section 3, we describe the new preparation of the
known complexes [Pt(SMe2)(triphos)]2ꢁ, (9), [Pt(py)-
(triphos)]2ꢁ, (10), and [Pt(PPh3)(triphos)]2ꢁ, (11).
The preparation and characterization of 9, 10 and 11
have been previously reported by us [5]; complex 11 has
been recently obtained also treating [PtCl(triphos)]Cl
with SnCl2 and PPh3 [3]. The synthetic route here
reported for these complexes represents an improvement
in terms of both time and yields (see Section 3).
ð6Þ
The cis geometry around the central Pd is indicated
by the presence, in the IR spectrum, of two bands of
medium intensity at 295 and 307 cmꢃ1 due to the
stretching of cis PdÃ
/
Cl bonds [19].
Complex 1 reacts with 0.5 equiv. of the dimeric
chloro-bridged complex [Rh(cod)Cl]2, in the presence
of aqueous NH4PF6, to give [Pt2RhMe4(cod)(tri-
phos)2]PF6, (8), as a couple of diastereoisomers, Eq. (7).
2.4. CO trapping
When a solution containing 1 in CH2Cl2 is saturated
with carbon monoxide and 2 equiv. of triflic acid are
added, the 31P{1H} NMR shows the carbonylic complex
[Pt(CO)(triphos)](Otf)2 as the only phosphorus contain-
ing product [d(PA)ꢀ
/
49.3 ppm, 1J(PtPA)ꢀ
/
2116 Hz;
2628 Hz]. Every attempt
ð7Þ
1
d(PB)ꢀ
/
98.4 ppm, J(PtPB)ꢀ
/
In the 31P{1H} NMR spectrum of 8, PC is observed as
a doublet of doublets at 28.1 ppm (1J(RhP) 150 Hz,
3J(PBPC)ꢀ
45 Hz). We did not succeed in isolating 8 as
a pure product because of the presence of variable
/
quantities of the side product [PtMe(triphos)]PF6, due
ꢁ
to the partial protonolysis of 1 by NH4
.
2.3. Formation of mononuclear dicationic complexes via
protonolysis of 1
Another consequence of the tendency of the dangling
phosphorus to coordinate to a metal is the high
susceptibility of 1 to double protonolysis involving
Scheme 1.

120
G. Annibale et al. / Inorganica Chimica Acta 333 (2002) 116ꢂ123
/
to isolate this product gave only [PtOTf(triphos)]OTf.
As previously noted, this behavior indicates that the
Erba instrument model EA1110. FT-IR spectra were
recorded on a Nicolet 510P FT-IR instrument (4000ꢂ
/
equilibrium
between
[PtOTf(triphos)]OTf
and
200 cmꢃ1) in CsI. NMR spectra were run on a Bruker
AM spectrometer 200 MHz for 1H NMR (TMS internal
reference) and 81.15 MHz for 31P{1H} NMR (H3PO4
85% external reference). 31P{1H} NMR spectra at
variable temperature were recorded on a Varian Gemini
300 spectrometer operating at 121.42 Hz. MS FAB (Fast
atomic bombardment) spectra were acquired by a
[Pt(CO)(triphos)](OTf)2 favors the CO complex only in
the presence of carbon monoxide (saturated solution of
CO in CH2Cl2), [5].
We tried to isolate the cation [Pt(CO)(triphos)]2ꢁ by
precipitating it in methanol as a salt of the non
coordinating anion BPh4ꢃ, excluding in this way the
competition between CO and the external anion. The
only product we obtained from this reaction was the
organometallic complex [Pt(COOMe)(triphos)]BPh4,
(12a), formed by the nucleophilic attach by methanol
on the coordinated CO [20]. In the Section 3 the
complete characterization of the new complex [Pt(COO-
Me)(triphos)]BPh4, (12a), is reported.
HewlettꢂPackard MS engine HP5989 A mass spectro-
/
meter using a p-nitrobenzylalcohol matrix.
3.1. Syntheses
3.1.1. [PtMe2(triphosPO-P,P?)], (2)
[Pt(COOMe)(triphos)]ꢁ can be obtained also as a
triflate by adding to a CH2Cl2 solution of 1 2 equiv. of
triflic acid, an excess of carbon monoxide and methanol
in sequence (Scheme 2). All attempts to isolate the
complex from this route led to isolation of [Pt(OTf)(tri-
phos)]OTf, probably generated by the protonolysis of
[Pt(COOMe)(triphos)]OTf, (12b), by the triflic acid
released in step (iii). All the Pt-complexes depicted in
Scheme 2 have been identified by 31P{1H} NMR [21].
a) Eight ml of H2O2 (3% in water) were added to a
solution containing 57 mg (0.075 mmol) of 1 in 3 ml
of benzene and the reaction mixture was stirred for
1 h. The organic phase was separated, dehydrated
over Na2SO4 and the solvent removed under
reduced pressure to leave a white solid (46 mg,
79%).
b) Alternatively the precursor 1 can be generated in
situ by dropwise addition of a solution containing
[PtMe2(cod)] (25 mg, 0.075 mmol) in 1 ml of the
distilled benzene to a second solution of an equi-
molar amount of triphos (40 mg, 0.075 mmol) in 2
ml of the same solvent, under nitrogen at room
temperature. After 30 min the complete formation
of 1 was checked by 31P{1H} NMR and the solution
was treated with aqueous H2O2 and worked up as
above. The reaction gave 48 mg of 2 (83%) (Found:
C, 55.6; H, 5.1. Calc. for C36H39OP3Pt: C, 55.7; H,
The ability shown by Ptꢂ
carbon monoxide may lead to useful catalysis by the
system [Pt(CO)(triphos)](OTf)2ꢂ[PtOTf(triphos)]OTf
/
triphos to uptake and release
/
and this will be investigated.
3. Experimental
[PtMe2(cod)], [PtCl2(cod)], [PtMeCl(cod)], [PtI2(cod)],
[PdCl2(cod)] and [RhCl(cod)]2 were prepared by litera-
1
2
5.1%). H NMR (CDCl3): 0.7 [6H, m, J(PtH) 69.4
Hz, PtÃ
/
CH3], 2.2 [8H, m, PÃ
/
CH2], 7.5 [25H, m,
aromatics]; 31P{1H} NMR (C6D6): 48.6 [PA, d,
ture methods [22ꢂ24].
/
[PtMe2(triphos-P,P?)], (1), was prepared as previously
reported [10].
All the other chemicals were purchased (reagent
grade) and solvents were distilled before using. Elemen-
tal analyses (C, H, N, S) were performed using a Carlo
2J(PBPA) 4.5 Hz, J(PtPA) 1810 Hz], 49.0 [PB, dd,
1
3J(PCPB) 53.2 Hz, J(PAPB) 4.6 Hz, J(PtPB) 1803
2
1
3
Hz], 33.2 [PC, d, J(PBPC) 53.2 Hz].
3.1.2. [Pt3Me6(triphos)2], (3)
a) Ninety one mg (0.12 mmol) of 1 were dissolved in 3
ml of distilled benzene and added dropwise to
second solution of [PtMe2(cod)] (20 mg, 0.06
mmol) in 2 ml of the same solvent. The mixture
was kept under stirring at room temperature for 1h
and then the solvent was removed in vacuo. The
residue was washed with diethyl ether and n-
pentane, filtered and dried over P2O5 (88.4 mg,
85%).
b) Alternatively a solution of [PtMe2(cod)] (74.6 mg,
0.225 mmol) in 2 ml of distilled benzene was added
under nitrogen to a stirred solution of triphos (80
mg, 0.15 mmol) in 2 ml of the same solvent. The
Scheme 2.

G. Annibale et al. / Inorganica Chimica Acta 333 (2002) 116ꢂ
/123
121
stirring was prolonged for 2 h and then the solvent
was removed to leave a white solid which was
washed with n-pentane. (106 mg, 81%). (Found: C,
51.1; H, 4.9. Calc. for C74H84P6Pt3: C, 50.9; H,
mixture was treated as above. The final product was
obtained as a white solid (114 mg, 77%). (Found: C,
44.1; H, 4.2. Calc. for C72H78I2P6Pt3: C, 44.0; H, 3.9%).
1H NMR (CDCl3): 0.55 [6H, m, J(PtH) 70 Hz, PtÃ
2
/
2
4.8%). 1H NMR(CDCl3): 0.3ꢂ
CH3], 1.1ꢂ1.6 [16H, m, PꢂCH2], 7.0ꢂ
aromatics].
/
0.8 [18H, m, PtÃ
/
CH3], 0.6 [6H, m, J(PtH) 69.4 Hz, PtÃ
/
CH3], 1.7ꢂ3.0
/
/
/
/
7.7 [50H, m,
[16H, m, PÃ
/
CH2], 7.3ꢂ
/
7.7 [50H, m, aromatics]; 31P{1H}
1
NMR (CDCl3): 48.8 [PA, m, J(PtPA) 1800 Hz], 49.4
31P{1H} NMR (CDCl3): two diastereomers dis-
1
1
[PB, m, J(PtPB) 1791 Hz], 5.7 [PC, m, J(PtPC) 2400
tinguishable D1 8.5 [PA, d, 1J(PtPA) 1801 Hz,
Hz].
1
2J(PBPA) 5.2 Hz], 47.6 [PB, dd, J(PtPB) 1797 Hz,
3
2J(PAPB) 5.2 Hz, J(PCPB) 16.7 Hz], 18.5 [PC, m,
3.1.6. [Pt2PdMe4Cl2(triphos)2], (7)
1
1J(PtPC) 1891 Hz]; D2 48.4 [PA, d, J(PtPA) 1802
A solution of [PdCl2(cod)] (21 mg, 0.075 mmol) in 1
ml of distilled benzene was added to a stirred solution of
1 (114 mg, 0.15 mmol) in 3 ml of the same solvent. After
15 min of stirring at room temperature, the reaction was
worked as above and the final product was isolated as a
pale yellow solid (81 mg, 64%). (Found: C, 50.8; H, 4.7.
Calc. for C72H78Cl2P6PdPt2: C, 50.9; H, 4.8%). IR (CsI)
2
Hz, J(PBPA) 4.7 Hz], 47.1 [PB, dd, J(PtPB) 1796
1
2
3
Hz, J(PAPB) 4.7 Hz, J(PCPB) 15.1 Hz], 18.0 [PC,
1
m, J(PtPC) 1891 Hz]; 31P{1H} NMR (DMSO-d6,
1
140 8C) 49.4 [PA, s, J(PtPA) 1803 Hz], 48.0 [PB, d,
1J(PtPB) 1784 Hz, 3J(PCPB) 35 Hz], 19.3 [PC, d,
3
1J(PtPC) 1866 Hz, J(PBPC) 35 Hz]. 31P{1H} NMR
(toluene-d8, 100 8C) 49.4 [PA, s, 1J(PtPA) 1792 Hz],
48.1 [PB, d, 1J(PtPB) 1763 Hz, 3J(PCPB) 42 Hz], 19.4
nmax (cmꢃ1) 307 and 295 (PdÃ
/
Cl). 31P{1H} NMR
1
(CDCl3): 48.6 [PA, m, J(PtPA) 1804 Hz], 49.4 [PB, m,
1J(PtPB) 1825 Hz], 18.4 [PC, m].
1
[PC, d, J(PtPC) 1869 Hz, J(PBPC) 42 Hz].
3
3.1.3. [Pt3Me4Cl2(triphos)2], (4)
3.1.7. [Pt2RhMe4(cod)(triphos)2]PF6, (8)
A solution of [PtCl2(cod)] (28 mg, 0.075 mmol) in 1 ml
of distilled benzene was added to a stirred solution of 1
(114 mg, 0.15 mmol). After 20 min of stirring, the
volume was reduced to a half in vacuo and the product
was precipitated with n-pentane. The white powder (94
mg, 70%) was filtered, washed with n-pentane and dried
over P2O5. (Found: C, 48.5; H, 4.6. Calc. for
A solution of [RhCl(cod)]2 (25 mg, 0.05 mmol) in 1 ml
of distilled CH2Cl2 was added under nitrogen to a
stirred deoxygenated aqueous solution (2 ml) of
NH4PF6 (50 mg, 0.3 mmol). A solution of 1, generated
in situ by 0.2 mmol of [PtMe2(cod)] and 0.2 mmol of
triphos in 3 ml of distilled CH2Cl2 as checked by
31P{1H} NMR, was added to this biphasic system. After
few min. of stirring, the organic yellow phase was
separated, dehydrated, taken to dryness in vacuo and
the yellow residue was washed with n-pentane. 31P{1H}
NMR shows that this product is always contaminated
by variable quantities of the side product [PtMe(tri-
phos)]PF6 and other species due to rapid decomposition;
for this reason a complete characterization was not
possible.
C72H78Cl2P6Pt3: C, 48.4; H, 4.4%). IR (CsI) nmax
1
Cl). H NMR (CDCl3): 0.4
(cmꢃ1) 341 and 292 (PtÃ
/
2
2
[6H, m, J(PtH) 70 Hz, PtÃ
69 Hz, PtÃCH3], 1.7ꢂ3.0 [16H, m, PÃ
[50H, m, aromatics]; 31P{1H} NMR (CDCl3): 48.8 [PA,
/
CH3], 0.55 [6H, m, J(PtH)
/
/
/
CH2], 6.8ꢂ8.0
/
1
1
m, J(PtPA) 1809 Hz], 49.4 [PB, m, J(PtPB) 1798 Hz],
1
9.6 [PC, m, J(PtPC) 3654 Hz].
1
3.1.4. [Pt3Me5Cl(triphos)2], (5)
31P{1H} NMR (CDCl3): 49.3 [PA, d, J(PtPA) 1797
2
1
The complex was obtained from 0.15 mmol (114 mg)
of 1 dissolved in 3 ml of distilled benzene and 0.075
mmol (26 mg) of [PtMeCl(cod)] in 3 ml of the solvent.
The work up was the same as previous. The final
product was obtained as a white solid (125 mg, 95%).
(Found: C, 49.6; H, 4.8. Calc. for C73H81ClP6Pt3: C,
Hz, J(PBPA) 5 Hz], 48.9 [PB, dd, J(PtPB) 1782 Hz,
3J(PCPB) 45 Hz, 2J(PAPB) 5 Hz], 28.1 [PC, dd, 1J(RhPC)
3
150 Hz, J(PBPC) 45 Hz].
3.2. Conversion of 1 into [PtL(triphos)](OTf)2, Lꢀ
/
SMe2, pyridine, PPh3
49.7; H, 4.6%). 1H NMR (CDCl3): ꢃ
0.03 [3H, t,
/
2
CH3], 0.6 [12H, m, J(PtH) 68.2
2J(PtH) 80 Hz, Pt(2)
Ã
/
In a typical reaction, 0.112 mmol of 1 have been
generated by adding a solution of [PtMe2(cod)] (37 mg,
0.112 mmol) in 2 ml of distilled CH2Cl2 to a second
solution containing triphos (60 mg, 0.112 mmol) in 2 ml
of the same solvent. After few minutes of stirring, the
complete formation of 1 was checked by 31P{1H} NMR
Hz, PtÃ
/
CH3], 1.7ꢂ
/
3.2 [16H, m, PÃ
/
CH2], 7.3ꢂ7.8 [50H,
/
m, aromatics]; 31P{1H} NMR (CDCl3): 49.5 [PB, m,
1J(PtPB) 1799 Hz], 48.7 [PA, m, 1J(PtPA) 1810 Hz], 24.5
1
[PC, m, J(PtPC) 3070 Hz].
3.1.5. [Pt3Me4I2(triphos)2], (6)
and then 0.135 mmol (1.2 equiv.) of L (9 Lꢀ
/SMe2, 10
The complex was obtained from 0.15 mmol (114 mg)
of 1 dissolved in 3 ml of distilled benzene and 0.075
mmol (42 mg) of [PtI2(cod)] in 3 ml of the solvent. The
Lꢀpyridine, 11 LꢀPPh3) and HOTf (0.021 ml, 0.236
mmol, 2.1 equiv.) were added in this order. After 15 min
of stirring at room temperature, the solution was taken
/
/

122
G. Annibale et al. / Inorganica Chimica Acta 333 (2002) 116ꢂ123
/
3
˚
to dryness in vacuo. The solid residue was washed with
diethyl ether and dried over P2O5.
93.9560(5)8, Uꢀ
cmꢃ3. 13 205 reflections collected (35
unique reflections (Rint 0.070), mꢀ
4.059 mmꢃ1. Em-
/
7202.0(2) A , Zꢀ
/
8, Dcꢀ
/
1.490 g
/
u 5268), 6703
/
ꢀ
/
/
3.2.1. [Pt(SMe2)(triphos)](OTf)2, (9)
(107 mg, 87%) Found: C, 41.7; H, 3.65; S, 8.9. Calc.
pirical absorption correction using the program SORTAV
[25]. The crystal includes molecules of solvent (diethyl
ether) which show a high degree of disorder around
twofold axes. The structure was solved by direct
methods (SIR92, [26]) and refined by the full-matrix
least-squares method based on F2 (SHELXL-97, [27]) with
all non-hydrogen atoms anisotropic and hydrogens in
1
for C38H39F6O6P3PtS3: C, 41.87; H, 3.60; S, 8.82%). H
NMR (CD3OD): 1.9 (6H, d, 3J(PtH) 35 Hz, 4J(PH) 3.7
Hz, S(CH3)2), 2.9, 3.7 (8H, 2m, CH2Ã
/
CH2), 7.4ꢂ8.0
/
(25H, m, aromatics); 31P{1H} NMR (CD3OD): 48.7
1
[PA, s, J(PtPA) 2393 Hz], 94.2 [PB, s, J(PtPB) 2705
1
Hz)].
calculated positions. Final R [F2]
wR (F2, all reflections)ꢀ
0.203.
/
2s(F2)]ꢀ
0.079 and
/
/
3.2.2. [Pt(py)(triphos)](OTf)2, (10)
(116 mg, 93% yield). Found: C, 44.6; H, 3.45; N, 1.3;
S, 5.6. Calc. for C41H38F6NO6P3PtS2: C, 44.49; H, 3.46;
N, 1.26; S, 5.79%). 31P{1H} NMR (CD3OD): 49.4 [PA, s,
4. Supplementary material
1
1J(PtPA) 2408 Hz], 81.4 [PB, s, J(PtPB) 2825 Hz].
Crystallographic data (excluding structure factors)
have been deposited with the Cambridge Crystallo-
graphic Data Centre as supplementary publication N.
CCDC 173567. Copies of the data can be obtained free
of charge on application to CCDC, 12 Union Road,
3.2.3. [Pt(PPh3)(triphos)](OTf)2, (11)
(130 mg, 89%). (Found: C, 49.85; H, 3.55; S, 4.88.
Calc. for C54H48F6O6P4PtS2: C, 50.28; H, 3.75; S,
4.97%). 31P{1H} NMR (CDCl3): 12.7 [PPh3, dt,
Cambridge, CB2 1EZ, UK (fax: ꢁ44-1223-336 033; e-
mail: deposit@ccdc.cam.ac.uk).
/
2
1
2J(PBP) 297.6 Hz, J(PAP) 22.2 Hz, J(PtP) 2570 Hz],
1
44.5 [PA, d, J(PtPA) 2398 Hz], 94.0 [PB, d, J(PtPB)
1
2146 Hz].
Acknowledgements
3.3. Synthesis of [Pt(COOMe)(triphos)]BPh4, (12)
This work was supported by MURST (Project:
‘Pharmacological and diagnostic Properties of Metal
Complexes’). We thank Professor P.G. Pringle and M.
Murray (Bristol University) for useful discussions, the
Centro di Fotoreattivita` e Catalisi del C.N.R. (Ferrara,
Italy) for the availability of the NMR instrument and
Mr. M. Fratta for the elemental analyses and technical
assistance.
A solution of [PtMe2(cod)] (75 mg, 0.23 mmol) in 3 ml
of distilled CH2Cl2 was added to a stirred solution of
triphos (123 mg, 0.23 mmol) in 4 ml of the same solvent.
The solution was saturated with CO by bubbling for 10
min and then 2.2 equiv. of HOTf (45 ml) were added.
The volume was reduced to 2 ml using a continuous flow
of CO, and the solution diluted with 3 ml of methanol.
A solution containing an excess of NaBPh4 in methanol
(120 mg, 0.35 mmol in 3 ml) was finally added to
precipitate a white solid which was filtered and washed
with methanol (210 mg, 82%). (Found: C, 64.70; H,
References
1
4.95. Calc. for C60H56BO2P3Pt: C, 64.98; H, 5.05%). H
[1] (a) D. Michos, X. Luo, R.H. Crabtree, Inorg. Chem. 31 (1992)
4245;
(b) A. Albinati, Q. Jiang, H. Ruegger, L.M. Venanzi, Inorg.
¨
NMR (CDCl3): 3.25 (3H, s, OOCH3), 1.2ꢂ
/
3.2 (8H, m,
CH2Ã
/
CH2), 6.6ꢂ
/
7.7 (45H, m, aromatics); 31P{1H}
NMR (CDCl3): 37.6 [PA, t, 1J(PtPA) 2676 Hz,
2J(PBPA) 7 Hz], 86.8 [PB, d, 1J(PtPB) 1584 Hz,
2J(PAPB) 7 Hz]. MS-FAB: 788 m/z, [Pt(COOMe)-
(triphos)]ꢁ.
Chem. 32 (1993) 4940.
[2] P. Sevillano, A. Habtemariam, S. Parsons, A. Castineiras, M.E.
Garcia, P.J. Sadler, J. Chem. Soc., Dalton Trans. (1999) 2861.
[3] K.D. Ferna`ndez, P. Sevillano, M.I. Garc`ıa-Seijo, A. Castineiras,
L. Ja`nosi, Z. Berente, L. Kolla`r, M.E. Garc`ıa-Ferna`ndez, Inorg.
Chim. Acta 312 (2001) 40.
[4] D. Tau, D.W. Meek, Inorg. Chem. 18 (1979) 3574.
[5] (a) G. Annibale, P. Bergamini, V. Bertolasi, M. Cattabriga, V.
Ferretti, Inorg. Chem. Comm. 3 (2000) 303;
3.4. X-ray crystal structure of [PtMe2(triphosPO-
P,P?)], (2)
(b) G. Annibale, P. Bergamini, M. Cattabriga, Inorg. Chim. Acta
316 (2001) 25.
Crystals of 2 were obtained from CHCl3 and Et2O.
[6] (a) Y. Yamamoto, T. Tanase, H. Ukaji, M. Hasegawa, T. Igoshi,
K. Yoshimura, J. Organomet. Chem. 498 (1995) C23;
(b) K.D. Tau, R. Uriarte, T.J. Mazanec, D.W. Meek, J. Am.
Chem. Soc. 101 (1979) 6614.
C36H39OP3Pt×
/
1/2(C4H10O), Mꢀ
/
812.73, colorless
crystal, Enraf Kappa CCD diffractometer with Mo Ka
˚
0.71073 A, graphite monochromatized).
radiation (lꢀ
Tꢀ295 K. Monoclinic, space group C2/c, aꢀ
15.8194(2), bꢀ
/
/
/
[7] A.L. Balch, R.R. Guimerans, J. Linehan, Inorg. Chem. 24 (1985)
290.
˚
/
13.2054(2), cꢀ
/
34.5578(6) A, bꢀ
/

G. Annibale et al. / Inorganica Chimica Acta 333 (2002) 116ꢂ
/123
123
[8] F.A. Cotton, B. Hong, Prog. Inorg. Chem. 40 (1992) 179.
[9] D.W. Meek, T.J. Mazanec, Acc. Chem. Res. 14 (1981) 266.
[10] K.D. Tau, D.W. Meek, J. Organomet. Chem. 139 (1977) C83.
[11] T.G. Appleton, M.A. Bennet, and I.B. Tomkins, J. Chem. Soc.,
Dalton Trans., (1976) 439.
[21] 31P{1H} NMR in CDCl3 of [PtOTf(triphos)]OTf: 48.6 [PA, s,
1J(PtPA) 2476 Hz], 78.1 [PB, s, 1J(PtPB) 3633 Hz]; [Pt(CO)(tri-
phos)](OTf)2: 49.3 [PA, s, 1J(PtPA) 2116 Hz], 98.4 [PB, s, 1J(PtPB)
2628 Hz]; [Pt(COOMe)(triphos)]OTf: 39.0 [PA, s, 1J(PtPA) 2652
Hz], 88.8 [PB, s, 1J(PtPB) 1605 Hz].
[12] P. Sevillano, A. Habtemariam, A. Castineiras, M.E. Garcia, P.J.
Sadler, Polyhedron 18 (1999) 383.
[22] (a) R. Bassan, K.H. Bryars, L. Judd, A.W.G. Platt, P.G. Pringle,
Inorg. Chim. Acta 121 (1986) L41;
[13] S.O. Grim, W.L. Briggs, R.C. Barth, C.A. Tolman, J.P. Jesson,
Inorg. Chem. 13 (1974) 1095.
(b) J. Soulie, J.C. Chottard, D. Mansuy, J. Organom. Chem. 171
(1979) 113;
[14] R.H. Reamey, G.M. Whitesides, J. Am. Chem. Soc. 106 (1984)
81.
(c) C. Clark, L.E. Manzer, J. Organom. Chem. 59 (1973) 411;
(d) J.X. McDermott, J.F. White, G.M. Whitesides, J. Am. Chem.
Soc. 98 (1976) 6521.
[15] (a) G.D. Macdonell, K.D. Berlin, J.R. Baker, S.E. Ealick, D. van
der Helm, K.L. Marsi, J. Am. Chem. Soc. 100 (1978) 4535;
(b) N.K. Roberts, S.B. Wild, J. Am. Chem. Soc. 101 (1979) 6254;
(c) P. Leung, A. Liu, K.F. Mok, Tetrahedron Asymmetric 10
(1999) 1309.
[23] D. Drew, J.R. Doyle, Inorg. Synth. 13 (1972) 47.
[24] G. Giordano, R.H. Crabtree, Inorg. Synth. 19 (1979) 218.
[25] B.H. Blessing, Acta Crystallogr. Sect A. 51 (1995) 33.
[26] A. Altomare, G. Cascarano, C. Giacovazzo, A. Guagliardi, M.C.
Burla, G. Polidori, M. Camalli, J. Appl. Crystallogr. 27 (1994)
435.
[16] I.M. Al-Najjar, Inorg. Chim. Acta 128 (1987) 93.
[17] R. Romeo, M.R. Plutino, L. Monsu` Scolaro, S. Stoccoro, G.
Minghetti, Inorg. Chem. 39 (2000) 4749.
[27] G.M. Sheldrick, SHELXL-97, Program for Crystal Structure
[18] N.W. Alcock, L. Judd, P.G. Pringle, Inorg. Chim. Acta 113 (1986)
L13.
Refinement, University of Gottingen, Germany, 1997.
¨
[28] C.K. Johnson, ORTEP II, Report ORNL-5138 Oak Ridge
National Laboratory, Oak Ridge, TN, USA, 1976.
[19] D.G. Cooper, J. Powell, Can. J. Chem. 51 (1973) 1634.
[20] J.E. Byrd, J. Halpern, J. Am. Chem. Soc. 93 (1971) 1634.