Synthesis and nucleophilic behavior of cis-[M(C6F5)2(Ph2PCHPPh 2)]- (M = Pd, Pt): C-Alkylation, metalation, and halogenation of coordinated bis(diphenylphosphino)methane. X-ray crystal structure of [Pt(C6F5)2(Ph2PCHIPPh 2)]·C5H12

Article abstract of DOI:10.1021/om950457v

The reaction of the neutral complexes cis-[M(C₆F₅)₂(Ph₂PCH ₂PPh₂)] [M = Pd (1a), Pt (1b)] with LDA (lithium diisopropylamide) or Li^tBu (tert-butyllithium) in THF readily affords the anionic derivatives [M( C₆F₅)₂(Ph₂PCHPPh₂)] ^- by deprotonation of the coordinated bis-(diphenylphosphino)methane (dppm). The reactivity of the carbanionic center thus generated toward a variety of substrates has been studied. The reaction with alkyl halides such as MeI or EtI gives the neutral, C-alkylated complexes cis-[M(C₆F₅)₂(Ph₂PCHRPPh ₂)] [M = Pd, R = Me (2a), Et (4a); M = Pt, R = Me (2b), Et (4b)], and the reaction with ClAuPPh₃ or O₃ClOAgPPh₃ gives the heterobimetallic species cis-M(C₆F₅)₂[Ph₂PCH(M′PPh ₃)PPh₂] [M = Pd, M′ = Au (5a) Ag (6a); M = Pt, M′ = Au (5b), Ag (6b)], in which the [Ph₂PCHPPh₂]^- ligand acts as a bridging, tridentate-P,P′,C ligand. The reactions with halogens (Cl₂, Br₂, I₂) or pentafluorophenyl halides (BrC₆F₅, IC₆F₅) produce the heterolytic cleavage of the X-X or X-C bond, giving the halogenated derivatives cis-[M(C₆F₅)₂(Ph₂PCHXPPh ₂)] [M = Pd, X = I (9a); M = Pt, X = Cl (Tb), Br (8b), I (9b)]. The reaction of [Pt(C₆F₅)₂(Ph₂PCHPPh ₂)]-with C₆F₅CN occurs with C-F bond cleavage, and the para-substituted product M(C₆F₅)₂[Ph₂-PCH(C₆F ₄CN-4)PPh₂] (10b) is obtained. The X-ray crystal structure of 9b·C₅H₁₂ is reported.

Full text of DOI:10.1021/om950457v

Organometallics 1996, 15, 309-316
309
Syn th esis a n d Nu cleop h ilic Beh a vior of
cis-[M(C6F 5)2(P h 2P CHP P h 2)]- (M ) P d , P t): C-Alk yla tion ,
Meta la tion , a n d Ha logen a tion of Coor d in a ted
Bis(d ip h en ylp h osp h in o)m eth a n e. X-r a y Cr ysta l
Str u ctu r e of [P t(C6F 5)2(P h 2P CHIP P h 2)]‚C5H12
Larry R. Falvello, J uan Fornie´s,* Rafael Navarro, Angel Rueda, and
Esteban P. Urriolabeitia
Departamento de Quı´mica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n, Consejo
Superior de Investigaciones Cientı´ficas, Universidad de Zaragoza, 50009 Zaragoza, Spain
Received J une 14, 1995X
The reaction of the neutral complexes cis-[M(C6F5)2(Ph2PCH2PPh2)] [M ) Pd (1a ), Pt (1b)]
with LDA (lithium diisopropylamide) or LitBu (tert-butyllithium) in THF readily affords the
anionic derivatives [M(C6F5)2(Ph2PCHPPh2)]- by deprotonation of the coordinated bis-
(diphenylphosphino)methane (dppm). The reactivity of the carbanionic center thus generated
toward a variety of substrates has been studied. The reaction with alkyl halides such as
MeI or EtI gives the neutral, C-alkylated complexes cis-[M(C6F5)2(Ph2PCHRPPh2)] [M )
Pd, R ) Me (2a ), Et (4a ); M ) Pt, R ) Me (2b), Et (4b)], and the reaction with ClAuPPh3
or O3ClOAgPPh3 gives the heterobimetallic species cis-M(C6F5)2[Ph2PCH(M′PPh3)PPh2] [M
) Pd, M′ ) Au (5a ), Ag (6a ); M ) Pt, M′ ) Au (5b), Ag (6b)], in which the [Ph2PCHPPh2]-
ligand acts as a bridging, tridentate-P,P′,C ligand. The reactions with halogens (Cl2, Br2,
I2) or pentafluorophenyl halides (BrC6F5, IC6F5) produce the heterolytic cleavage of the X-X
or X-C bond, giving the halogenated derivatives cis-[M(C6F5)2(Ph2PCHXPPh2)] [M ) Pd, X
) I (9a ); M ) Pt, X ) Cl (7b), Br (8b), I (9b)]. The reaction of [Pt(C6F5)2(Ph2PCHPPh2)]-
with C6F5CN occurs with C-F bond cleavage, and the para-substituted product M(C6F5)2[Ph2-
PCH(C6F4CN-4)PPh2] (10b) is obtained. The X-ray crystal structure of 9b‚C5H12 is reported.
In tr od u ction
with functionalized dppm, since it has been shown4 that
the treatment of the free ligand salts [Li(Ph2PCHPPh2)]
with electrophiles generally gives mixtures of products
resulting from attack on carbon and phosphorus atoms.
For instance, complexes with C-alkylated dppm have
been reported,5 and only very recently have halogena-
tion reactions of the coordinated [Ph2PCHPPh2]- been
described6 in which, in almost all cases, carbonyl
derivatives of transition metals with low oxidation
numbers have been used. Despite this, the use of bis-
(diphenylphosphino)methanide complexes of MII (M )
Pd, Pt) in alkylation reactions has barely been
examined,5c,f and, as far as we know, there are no
examples of halogenation and/or metalation reactions.
We report here the synthesis of the anionic deriva-
tives [M(C6F5)2(Ph2PCHPPh2)]- (M ) Pd, Pt) and their
reactivity as nucleophiles in alkylation, halogenation,
and metalation reactions, all of which are “site-selective”
to the bridgehead carbon atom. We also discuss the
scope of their application to the synthesis of function-
alized dppm.
Bis(diphenylphosphino)methane (Ph2PCH2PPh2 or
dppm) is, among the diphosphine compounds, one of the
most commonly employed ligands in inorganic and
organometallic chemistry.1 Its wide range of applicabil-
ity extends from the synthesis of homo- and heteropoly-
nuclear clusters1 to homogeneous catalysis.2 The re-
lated compound bis(diphenylphosphino)methanide
[Ph2PCHPPh2]- (obtained from deprotonation of dppm)
has also been widely used in the synthesis of poly-
nuclear complexes.3
One of the most interesting applications of the
complexes containing the methanide form arises from
their use as intermediates in the synthesis of complexes
X Abstract published in Advance ACS Abstracts, November 15, 1995.
(1) (a) Puddephatt, R. J . Chem. Soc. Rev. 1983, 12, 99. (b) Chaudret,
B.; Delavaux, B.; Poilblanc, R. Coord. Chem. Rev. 1988, 86, 191.
(2) Pignolet, L. H. In Homogeneous Catalysis with Metal Phosphine
Complexes; Plenum Press: New York, 1983.
(3) (a) Laguna, A.; Laguna, M. J . Organomet. Chem. 1990, 394, 743
and references given therein. (b) Riera, V.; Ruiz, J . J . Organomet.
Chem. 1986, 310, C36. (c) Benlaarab, H.; Chaudret, B.; Dahan, F.;
Poilblanc, R. J . Organomet. Chem. 1987, 320, C51. (d) Riera, V.; Ruiz,
J .; Solans, X.; Tauler, E. J . Chem. Soc., Dalton Trans. 1990, 1607. (e)
Ruiz, J .; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.; Garc´ıa-Ferna´n-
dez, A. Organometallics 1992, 11, 4077. (f) Ruiz, J .; Arauz, R.; Riera,
V.; Vivanco, M.; Garc´ıa-Granda, S.; Pe´rez-Carren˜o, E. J . Chem. Soc.,
Chem. Commun. 1993, 740. (g) Karsch, H. H.; Grauvogl, G.; Kawecki,
M.; Bissinger, P. Organometallics 1993, 12, 2757. (h) Karsch, H. H.;
Ferazin, G.; Steigelmann, O.; Kooijman, H.; Hiller, W. Angew. Chem.,
Int. Ed. Engl. 1993, 32, 1739. (i) Karsch, H. H.; Grauvogl, G.; Kawecki,
M.; Bissinger, P.; Kumberger, O.; Schier, A.; Muller, G. Organometal-
lics 1994, 13, 610. (j) Ferna´ndez, E. J .; Gimeno, M. C.; J ones, P. G.;
Laguna, A.; Laguna, M.; Lo´pez-de-Luzuriaga, J . M. Angew. Chem., Int.
Ed. Engl. 1994, 33, 87.
(4) (a) Issleib, K.; Abicht, H. P. J . Prakt. Chem. 1970, 312, 456. (b)
Appel, R.;Hambrich, G.; Knoch, F. Chem. Ber. 1984, 117, 2063.
(5) (a) Al-J ibori, S.; Shaw, B. L. J . Chem. Soc., Chem. Commun.
1982, 286. (b) Al-J ibori, S.; Shaw, B. L. Inorg. Chim. Acta 1982, 65,
L123. (c) Al-J ibori, S.; Shaw, B. L. Inorg. Chim. Acta 1983, 74, 235.
(d) Cooper, G. R.; McEwan, D. M.; Shaw, B. L. Inorg. Chim. Acta 1983,
76, L165. (e) Al-J ibori, S.; Hall, M.; Hutton, A. T.; Shaw, B. L. J . Chem.
Soc., Dalton Trans. 1984, 863. (f) Hashimoto, H.; Nakamura, Y.; Okeya,
S. Inorg. Chim. Acta 1986, 122, L9. (g) Scherhag, F.; Ka¨b, H.; Bright,
T. A.; Malisch, W. J . Organomet. Chem. 1990, 385, C27.
(6) Ruiz, J .; Arauz, R.; Riera, V.; Vivanco, M.; Garc´ıa-Granda, S.;
Mene´ndez-Velazquez, A. Organometallics 1994, 13, 4162.
0276-7333/96/2315-0309$12.00/0 © 1996 American Chemical Society

310 Organometallics, Vol. 15, No. 1, 1996
Falvello et al.
Sch em e 1. Sch em a tic Rep r esen ta tion of th e Rea ction s P er for m ed for th e Syn th esis of Com p lexes 2a -10b
Resu lts a n d Discu ssion
of MeI (molar ratio ranging from 1:5 to 1:10, see the
Experimental Section) affords the C-monoalkylated
derivatives [M(C6F5)2(Ph2PCHMePPh2)] [M ) Pd (2a ),
Pt (2b)], together with small amounts (less than 10%)
of the dialkylated derivatives [M(C6F5)2(Ph2PCMe2-
PPh2)] [M ) Pd (3a ), Pt (3b)] (see Scheme 1), through a
typical aliphatic nucleophilic substitution process. Com-
plexes 2a and 2b can be isolated in analytically pure
form by recrystallization of the mixtures from CH2Cl2/
n-hexane. The 31P{1H} NMR spectra of both complexes
(see Table 1) show a single resonance, with 195Pt
satellites for 2b, slightly broadened due to the presence
of the trans-C6F5 groups. This resonance has undergone
a downfield shift with respect to the starting dppm
compounds 1a or 1b of the same magnitude as that
observed for the complexes M(CO)4(dppm-Me) (M ) Cr,
Mo, W)5c or PtX2(dppm-Me).5c The 1H NMR spectra
show a triplet of quartets at about 4.7-4.9 ppm,
attributed to the P2CH proton, and a triplet of doublets
at about 1.0-1.2 ppm, attributed to the P2CMe unit.
These observations show that the methylation process
has been produced selectively at the central (CH) carbon
Syn th esis of [M(C6F 5)2(P h 2P CHP P h 2)]-. We have
recently shown that a convenient route for the synthesis
of bis(diphenylphosphino)methanide derivatives of MII
(M ) Pd, Pt) is the treatment of acac-O,O′ complexes
with a stoichiometric amount of dppm.7 However, the
reaction of (NBu4)[M(C6F5)2(acac)] with dppm (1:1 molar
ratio) does not afford the expected (NBu4)[M(C6F5)2(Ph2-
PCHPPh2)] methanide complexes. Instead, the neutral
species M(C6F5)2(dppm) are obtained. Furthermore,
treatment of M(C6F5)2(dppm) with nBuLi in C6H6 or
THF also fails to yield the corresponding methanide
derivatives; the starting compounds are recovered un-
altered.
We had more success using other strong bases such
as LDA (lithium diisopropylamide, LiNiPr2) or tBuLi
(tert-butyllithium). In fact, the reaction between
t
M(C6F5)2(dppm) [M ) Pd (1a ), Pt (1b)] and LDA or -
BuLi (molar ratio 1:1.2) in THF at room temperature
gives deep yellow solutions of the carbanionic complexes
[M(C6F5)2(Ph2PCHPPh2)]- (see Scheme 1). These solu-
tions are quite air- and moisture-sensitive, and upon
exposure to air, the yellow color disappears in a few
seconds, indicating the protonation of the carbanionic
center. This behavior contrasts markedly with the
relatively high air and moisture stability of the related
neutral complexes [M(C6F5)(Ph2PCHPPh2)(PR3)].7 Be-
cause of that, freshly prepared solutions of [M(C6F5)2-
(Ph2PCHPPh2)]- are used in the reactions to be de-
scribed.
atom and not at the phosphorus atom. The simulta-
1
neous observation of the coupling constants J Pt-P
,
2J P-H, J P-H, and J H-H indicates that the ring MP2-
CHMe behaves as a rigid body in solution and that there
are no proton interchange processes, which could give
an inversion in the configuration at the central carbon
atom. This point is important in the discussion of the
19F NMR spectra (see the following).
3
3
The dialkylated complexes [M(C6F5)2(Ph2PCMe2-
PPh2)] [M ) Pd (3a ), Pt (3b)], which were obtained as
impurities in the synthesis of 2a and 2b, were not
isolated in pure form, but they were characterized
spectroscopically by 1H and 31P{1H} NMR (see Table 1).
Alk yla t ion R ea ct ion s. The reaction between
[M(C6F5)2(Ph2PCHPPh2)]- (M ) Pd, Pt) and an excess
(7) Fornie´s, J .; Navarro, R.; Urriolabeitia, E. P. J . Organomet. Chem.
1990, 390, 257.

cis-[M(C6F5)2(Ph2PCHPPh2)]-
Organometallics, Vol. 15, No. 1, 1996 311
1
Ta ble 1. H a n d 31P {1H} NMR Da ta [δ (p p m ), J (Hz)] for Com p lexes 2a -10b
compound
δ(C-H)
2J P-H
others
δ(M-P)
-16.60
δ(M′-P)
1J Pt-P
3J P-P
Pd(C6F5)2(dppm-Me) (2a )
4.89 (tq)
14.0
12.5
1.22 (Me, td)
3J P-H ) 14; 3J H-H ) 7
1.06 (Me, td)
Pt(C6F5)2(dppm-Me) (2b)
Pd(C6F5)2(dppm-Me2) (3a )
Pt(C6F5)2(dppm-Me2) (3b)
Pd(C6F5)2(dppm-Et) (4a )
Pt(C6F5)2(dppm-Et) (4b)
4.73 (tq)
-27.89
1.25
1991
3J P-H ) 15; 3J H-H ) 7.4
1.72 (Me, t)
3J P-H ) 15
1.46 (Me, t)
-10.55
-14.73
-26.42
2085
3J P-H ) 15.3
4.56 (tt)
4.57 (m)
12
1.56 (CH2, m); 0.93 (Me, t)
3J H-CH ) 6.9
3J CH
) 7.3
2-CH3
2
12
1.42 (CH2, m); 0.92 (Me, t)
1991
1991
3J H-CH ) 7.2
3J CH
) 7.3
2-CH3
2
Pd(C6F5)2(dppm-AuPPh3) (5a )
Pt(C6F5)2(dppm-AuPPh3) (5b)
Pd(C6F5)2(dppm-AgPPh3) (6a )
4.35 (q)
5.33 (q)
4.09 (br)
8.0
8.6
7.9
-24.91
-35.39
-27.69
1J P-
40.60
40.16
15.2
) 560.9; J P-
14.99
9
12
3J CH-Pt ) 104
1
109Ag
107Ag
) 487.7
Pt(C6F5)2(dppm-AgPPh3)a (6b)
5.29 (t, br)
8.0
-39.13
1963
6.5
107Ag
) 496.9
1J P-
) 573.5; J P-
1
109Ag
Pt(C6F5)2(dppm-Cl) (7b)
Pt(C6F5)2(dppm-Br) (8b)
Pd(C6F5)2(dppm-I) (9a )
Pt(C6F5)2(dppm-I) (9b)
5.92 (t)
6.06 (t)
6.08 (t)
6.01 (t)
6.53 (t)
10.1
10
10.6
10.7
12
-6.89
-10.87
-6.35
-18.53
-20.44
1970
1966
1916
2040
Pt(C6F5)2(dppm-C6F4CN) (10b)
a
-80 °C; t, triplet; tt, triplet of triplets; tq, triplet of quartets; td, triplet of doublets; m, multiplet; q, quartet; br, broad.
The 31P{1H} NMR spectra show a single resonance
shifted downfield with respect to 2a or 2b by nearly the
same displacement as that found for the complexes
M(CO)4(dppm-Me2) (M ) Cr, Mo, W)5c or PtX2(dppm-
observed lack of reactivity could be due to the contribu-
tion of two concomitant factors: (i) the already discussed
withdrawing nature of the C6F5 ligands and (ii) the
known decreasing alkylating power in the series MeI
> EtI, PhCH2Br > PrI, PrI for the aliphatic nucleo-
philic substitution.
1
n
i
Me2).5c The H NMR spectra show a triplet resonance
(about 1.5 ppm) attributed to the CMe2 unit.
Despite the clear reactivity observed between
[M(C6F5)2(Ph2PCHPPh2)]- and MeI, the alkylation pro-
cess with EtI is not so straightforward. In fact, when
these reactions are carried out under the same condi-
tions as those described for 2a or 2b (see Experimental
Section), a mixture of the C-ethylated complexes
[M(C6F5)2(Ph2PCHEtPPh2)] [M ) Pd (4a ), Pt (4b)] and
the corresponding starting compounds 1a or 1b (molar
ratio around 1.3:1) is obtained. An excess of the
deprotonating agent and/or longer reaction times (up
to 24 h) do not improve the percentage of conversion.
We have attempted the separation of the two products
by repeated recrystallizations, but in all cases we obtain,
both in the crystallized fraction as well as in the mother
liquor, a mixture of the same (or nearly the same)
composition, probably due to the similar solubilities of
these complexes. However, the complete spectroscopic
characterization of 4a and 4b has been possible. The
31P{1H} NMR spectra show a single resonance in the
same region as that found for 2a or 2b (see Table 1).
Rea ction s w ith Electr op h ilic Meta l Su bstr a tes.
The anionic complexes [M(C6F5)2(Ph2PCHPPh2)]- (M )
Pd, Pt) react with ClAuPPh3 or O3ClOAgPPh3 (molar
ratio 1:1; see Scheme 1) to give the heterobimetallic
derivatives M(C6F5)2[Ph2PCH(M′PPh3)PPh2] [M ) Pd,
M′ ) Au (5a ), Ag (6a ); M ) Pt, M′ ) Au (5b), Ag (6b)]
in moderate to good yields. Attempts to obtain the silver
derivatives by reaction of [M(C6F5)2(Ph2PCHPPh2)]-
with ClAgPPh3 were not successful, yielding unaltered
ClAgPPh3 at the end of the reaction together with
[M(C6F5)2(Ph2PCH2PPh2)], with the protonation having
occurred during the workup.
The spectroscopic data for these complexes show that
the incorporation of the [M′PPh3]+ fragment has oc-
curred at the methanide center. Thus, the 31P{1H}
NMR spectra of the gold derivatives 5a and 5b (see
Table 1) show the presence of two resonances: a broad
singlet at high field (-24.9 ppm for 5a and -35.4 ppm
for 5b with 195Pt satellites, both slightly broadened by
the presence of trans-C6F5 groups) attributed to the
phosphorus of the MPCP ring and another resonance
at low field (around 40 ppm) with triplet structure (3J P-P
coupling with the phosphorus of the MPCP ring) and
attributed to the PPh3 ligand linked to the gold atom.
1
The H NMR spectra show the expected resonances for
the MP2C(H)CH2CH3 unit: a complex multiplet of
relative intensity 1 around 4.6 ppm (CH), another
multiplet of relative intensity 2 centered about 1.5 ppm
(CH2), and a triplet (intensity 3) at 0.9 ppm (CH3).
The results obtained contrast with the easy
C-ethylation5c of [PtI2(Ph2PCHPPh2)]-, but could be
explained by taking into account the withdrawing
ability of the pentafluorophenyl ligands. A lower elec-
tronic density at the metal center would give a less
nucleophilic carbanionic group, as in our case. The
same result (partial conversion) is observed when the
anions [M(C6F5)2(Ph2PCHPPh2)]- are allowed to react
with PhCH2Br, although in this case the conversion is
even worse (ca. 20%). Finally, no reaction is observed
1
The resonance of the methine proton appears in the H
NMR spectra as a false quartet (2J P-H = 3J P-H) and also
shows 195Pt satellites for 5b. The 31P{1H} NMR spec-
trum of 6a also shows a singlet resonance at high field
(MPCP ring) and a doublet of doublets (coupling with
109Ag and 107Ag) at low field due to the PPh3 ligand
bonded to the silver center. A similar pattern of
resonances is observed for complex 6b although in this
case the spectrum has to be measured at low temper-
atures to observe the complete splitting of the PPh3
109
signal (doublet of doublets of triplets: coupling with
-
i
between [M(C6F5)2(Ph2PCHPPh2)]- and nPrI or PrI. The
Ag and 107Ag and with the P nucleus of the MPCP ring),

312 Organometallics, Vol. 15, No. 1, 1996
Ta ble 2. 19F NMR Da ta [δ (p p m ), J (Hz)] for Com p lexes 2a -10b
Falvello et al.
compound
δ(Fo)
δ(Fp)
δ(Fm
)
δ(Fo)
δ(Fp)
δ(Fm) (-90 °C/CD2Cl2)
-163.60
Pd(C6F5)2(dppm-Me) (2a )
-115.07
-162.65
-164.72
-164.38
-163.98
-164.37
-164.42
-164.19
-163.86
-160.92
-163.99
-163.94
-163.45
-164.08
-163.93
-114.00
-115.77
-116.04
-117.84
-113.58
-115.31
-116.25
-117.99
-110.73
-112.48
-116.53
-117.12
-112.45
-113.78
-114.41
-115.03
-161.28
Pt(C6F5)2(dppm-Me) (2b)
Pd(C6F5)2(dppm-Et) (4a )
Pt(C6F5)2(dppm-Et) (4b)
Pd(C6F5)2(dppm-AuPPh3) (5a )
Pt(C6F5)2(dppm-AuPPh3) (5b)
Pd(C6F5)2(dppm-AgPPh3) (6a )
Pt(C6F5)2(dppm-AgPPh3) (6b)
Pt(C6F5)2(dppm-Cl) (7b)
-116.94
-162.43
-161.86
-162.55
-162.79
-162.98
-161.77
-158.80
-161.51
-161.63
-160.91
-161.65
-161.45
-161.34
-163.42
3J Pt-F ) 322
-115.o06
3J Pt-F ) 318
-160.o85
3J Pt-F ′ ) 336
-163.o07
-117.06
-161.40
-163.37
3J Pt-F ) 338
-113.o33
3J Pt-F ) 310
-161.o47
3J Pt-F ′ ) 318
-163.o10
-117.14
-162.48
-163.80
3J Pt-F ) 340
-115.o00
3J Pt-F ) 347
-160.o75
3J Pt-F ′ ) 333
-162.o89
-114.32
-162.66
-163.90
3J Pt-F ) 324
-117.o50
3J Pt-F
)
3J Pt-F ′ ) 356
o
o
3J Pt-F ) 370
-116.o95
Pt(C6F5)2(dppm-Br) (8b)
Pd(C6F5)2(dppm-I) (9a )
-116.98
-118.75
-114.88
-115.20
-116.65
-118.18
-114.99
-116.50
-161.43
-163.94
3J Pt-F ) 332
-115.o13
3J Pt-F ) 339
-160.o22
3J Pt-F ′ ) 325
-162.o95
Pt(C6F5)2(dppm-I) (9b)
-117.80
-160.93
-163.36
3J Pt-F ) 324
-117.o68
3J Pt-F ) 336
3J Pt-F ′ ) 336
-163.o42
Pt(C6F5)2(dppm-C6F4CN) (10b)
-160.o94
3J Pt-F ) 327
3J Pt-F ) 338
3J Pt-F ′ (nr)
o
o
C6F4CN: -130.20 (br), -130.92 (d)
-129.87, -131.67, -131.97, -13o5.36
a
br, broad; d, doublet; nr, not resolved.
which at room temperature appears very broadened (see
the following for the 19F NMR discussion).
have not characterized. On the other hand, the reaction
between [M(C6F5)2(Ph2PCHPPh2)]- (M ) Pd, Pt) and
C6F6, under the same conditions as those used with
BrC6F5, gives [M(C6F5)2(Ph2PCH2PPh2)] as the only
identified product, with the protonation having occurred
during the workup. This behavior can be explained by
taking into account the fact that the reaction occurs
through a simple metal-halogen exchange, similar to
that used in the preparation of several organolithium
compounds,9 and the nature of the reactants. Here, we
clearly see the lesser nucleophilic character of the
palladium complexes compared to that of the platinum
ones10 (the anionic Pt derivative reacts with Cl2 while
the Pd one does not). On the other hand, the increasing
strength of the halogen-halogen bond (I2 < Br2 < Cl2)
and that of the halogen-carbon bond (I-C6F5 < Br-
C6F5 < F-C6F5) also play an important role: 7b is
obtained but with low conversion, while good yields of
8b or 9b are obtained.
For complexes 5a , 5b, and 6a , the NMR data are in
keeping with the rigid behavior of the MP2CH(M′PPh3)
ring in solution, while for 6b equilibrium dissociative
processes must be present at room temperature.8 More-
over, they confirm that the [Ph2PCHPPh2]- group is
acting as a tridentate, six-electron donor ligand. As far
as we know, these are the first examples of this
coordination mode in palladium and platinum chemis-
try, obtained through the deliberate use of the chelating
[Ph2PCHPPh2]- group as a C donor ligand to another
metal center.
Ha logen a tion Rea ction s. The nucleophilic char-
acter at the central carbon atom in the methanides
[M(C6F5)2(Ph2PCHPPh2)]- can also promote the hetero-
lytic cleavage of the halogen-halogen bond in dihalogen
molecules such as Cl2, Br2, or I2 and even that of the
halogen-carbon bond in species such as BrC6F5 or IC6F5
(see Scheme 1 and the Experimental Section). Thus,
[Pt(C6F5)2(Ph2PCHPPh2)]- reacts in THF with Cl2 (1:1
molar ratio) to give [Pt(C6F5)2(Ph2PCHClPPh2)] (7b), but
the conversion obtained is low (10%). Better conver-
sions are obtained when [Pt(C6F5)2(Ph2PCHPPh2)]-
reacts with Br2 (1:1 molar ratio) or BrC6F5 (excess) to
give [Pt(C6F5)2(Ph2PCHBrPPh2)] (8b) as the only reac-
tion product. Moreover, [Pd(C6F5)2(Ph2PCHPPh2)]- re-
acts with I2 (1:1 molar ratio) or IC6F5 (excess) to give
[Pd(C6F5)2(Ph2PCHIPPh2)] (9a ) in good yield, and the
reaction between [Pt(C6F5)2(Ph2PCHPPh2)]- and I2 (1:1
molar ratio) also gives the iodine derivative [Pt-
(C6F5)2(Ph2PCHIPPh2)] (9b) in good yield.
Complexes 7b-9b show similar spectroscopic fea-
tures: the 31P{1H} NMR spectra (see Table 1) show a
single resonance strongly shifted downfield with respect
to the starting products as a result of the substitution
of H by the more electronegative halogen atom. Simi-
1
larly, the methine P2CHX resonance appears in the H
NMR spectra as a triplet at higher frequency (about 2
ppm) than the P2CH2 hydrogens in the corresponding
precursors. The 19F NMR spectra also show similar
characteristics for all complexes and will be discussed
later. As in the preceding cases, these NMR data show
that halogenation has occurred selectively at the meth-
anide center. Similar halogen-halogen bond cleavages
have been reported6 for [Mn(CO)4(Ph2PCHPPh2)], which
Other attempted halogenation reactions did not give
such successful results: the reaction of [Pd(C6F5)2-
(Ph2PCHPPh2)]- with Cl2, Br2, or BrC6F5 results in the
formation of a complex mixture of species, which we
(9) Wakefield, B. J . In The Chemistry of Organolithium Compounds;
Pergamon Press: Oxford, U.K., 1974; p 51.
(10) This lesser nucleophilic character can be shown, for instance,
by the different reactivities of anionic palladium and platinum
complexes toward electrophilic substrates; some examples are given
in refs 8 and 12.
(8) Uso´n, R.; Fornie´s, J .; Falvello, L. R.; Toma´s, M.; Casas, J . M.;
Mart´ın, A. Inorg. Chem. 1993, 32, 5212.

cis-[M(C6F5)2(Ph2PCHPPh2)]-
Organometallics, Vol. 15, No. 1, 1996 313
Ta ble 4. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s
(Å2 × 103) for 9ba
x
y
z
U(eq)
Pt
I
P
510(1)
167(1)
397(1)
2500
2500
4797(1)
9444(1)
6483(1)
3436(5)
3408(6)
2487(7)
1531(6)
1531(5)
2464(5)
4330(4)
2491(5)
610(4)
34(1)
65(1)
36(1)
38(1)
53(1)
62(2)
56(2)
53(1)
44(1)
88(1)
102(2)
87(1)
82(1)
71(1)
44(1)
72(2)
90(3)
93(3)
104(3)
74(2)
41(1)
47(1)
65(2)
72(2)
69(2)
57(2)
36(2)
185(11)
194(10)
60(2)
240(13)
214(12)
3184(1)
3218(2)
3460(3)
3917(3)
4144(3)
3923(3)
3462(3)
3258(2)
4129(2)
4564(2)
4137(2)
3260(2)
3873(2)
4397(3)
4943(4)
4963(4)
4452(4)
3902(4)
3527(2)
3383(3)
3656(4)
4067(4)
4207(3)
3946(3)
2500
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
F(2)
F(3)
F(4)
F(5)
F(6)
C(7)
C(8)
C(9)
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)
651(5)
1916(6)
2088(6)
947(6)
-346(6)
-465(5)
3081(3)
3367(4)
1107(4)
-1473(4)
-1773(3)
1589(5)
1477(8)
2362(10)
3346(9)
3465(9)
2588(8)
-1294(5)
-2410(5)
-3692(6)
-3898(7)
-2803(7)
-1490(7)
869(8)
589(3)
2385(3)
7034(5)
6157(8)
6510(11)
7718(11)
8561(10)
8222(7)
6391(5)
5300(5)
5213(7)
6177(8)
7255(7)
7375(6)
7720(7)
7484(24)
8756(25)
9443(9)
10676(28)
11578(20)
F igu r e 1. ORTEP representation of the molecular struc-
ture of complex 9b.
Ta ble 3. Selected Bon d Len gth s (Å) a n d
An gles (d eg) for 9b
Pt-C(1)
2.067(5)
2.133(7)
1.807(5)
0.93(8)
Pt-P
P-C(13)
P-C(19)
2.276(2)
1.803(5)
1.858(5)
I-C(19)
P-C(7)
C(19)-H(19)
4923(28)
5503(23)
4433(9)
5095(25)
4441(28)
2500
2500
2500
2500
C(1)#1-Pt-C(1)a
C(1)-Pt-P
C(13)-P-C(7)
C(7)-P-C(19)
C(7)-P-Pt
C(2)-C(1)-Pt
C(12)-C(7)-P
C(14)-C(13)-P
P#1-C(19)-I
P-C(19)-H(19)
88.2(3)
C(1)-Pt-P#1
P#1-Pt-P
172.80(13)
74.09(7)
111.3(3)
116.5(2)
92.6(2)
124.3(4)
116.5(5)
121.5(4)
121.3(2)
115(5)
98.82(14)
104.4(2)
109.1(3)
122.3(2)
120.9(4)
124.7(5)
119.0(4)
121.3(2)
100(3)
C(13)-P-C(19)
C(13)-P-Pt
C(19)-P-Pt
C(6)-C(1)-Pt
C(8)-C(7)-P
C(18)-C(13)-P
P-C(19)-I
2500
a
U(eq) is defined as one-third of the trace of the orthogonalized
Uij tensor.
environment formed by the two Cipso atoms of the C6F5
groups and the two phosphorus atoms of the chelate Ph2-
PCH(I)PPh2 ligand. The Pt-C(1) and Pt-P(1) bond
distances (2.067(5) and 2.276(2) Å, respectively) are
similar to distances found in other pentafluoro-12 and
dppm-containing13 platinum complexes. The P(1)-Pt-
P(1′) (74.09(7)°) and P(1)-C(19)-P(1′) (95.2(3)°) angles
are reduced significantly from the usual normal bond
angles of 90° and 109°, due to the strain in the chelate
ring arising from the small bite of the phosphine ligand,
and these angles are typical for chelating dppm.1a,b,14
The P(1)-C(19) [P-CH(I)] distance (1.858(5) Å) is
longer than other P-C(Ph) distances found in the same
molecule (1.803(5), 1.807(5) Å) and is also typical for
chelating dppm, showing that no double-bond character
remains in these bonds. The C(19)-I(1) distance (2.133-
(7) Å) is longer than that in iodoarenes15 and the angles
around C(19) average 111.3°, which is close to the 109.5°
expected for sp3 hybridization, although the two inde-
pendent angles are very different from each other (i.e.,
P(1)-C(19)-P(1′) ) 95.2(3)°; P(1)-C(19)-I(1) ) 121.3-
(2)°). On the other hand, the MP2C ring is appreciably
bent, with the carbon atom C(19) lying 0.52(1) Å out of
the Pt-P(1)-P(1′) plane. Moreover, this bending is
produced in such a way that the iodine atom is directed
to the less sterically crowded position (opposite the
platinum atom position).
I-C(19)-H(19)
a
Symmetry transformations used to generate equivalent atoms.
#1: x, -y + 1/2, z.
can be halogenated to give [Mn(CO)4(Ph2PCHXPPh2)]+
and subsequently [Mn(CO)4(Ph2PCXPPh2)] and [Mn-
(CO)4(Ph2PCX2PPh2)]+. These reactions are, as in our
case, noteworthy because of their chemoselectivity and
the fact that no side reactions (such as oxidations) are
observed. For instance, oxidation processes take place
when the free anions Li[E(PPh2)2] (E ) CH, N) react
with I2, giving interesting P-P or P-C coupling prod-
ucts, but in no case has the product of direct iodination
been detected.11
The X-ray crystal structure of compound 9b‚C5H12 has
been determined. Suitable crystals of 9b‚C5H12 were
obtained by slow diffusion of petroleum ether into a CH2-
Cl2 solution of 9b at -18 °C. A drawing of the structure
is presented in Figure 1. Selected bond distances
(angstroms) and angles (degrees) are collected in Table
3. Positional parameters and their estimated standard
deviations are listed in Table 4.
The molecular structure involves the packing of two
discrete monomeric molecules in the unit cell, which
belongs to the centrosymmetric space group P21/m.
Thus, the molecule has an imposed crystallographic
symmetry of m; the platinum center, the methanide CH,
and the iodine atom lie in the mirror plane. The
platinum atom is located in a distorted square planar
(12) Fornie´s, J .; Navarro, R.; Toma´s, M.; Urriolabeitia, E. P.
Organometallics 1993, 12, 940 and references cited therein.
(13) J ain, V. K.; Kannan, S.; Butcher, R. J .; J asinski, J . P. J . Chem.
Soc., Dalton Trans. 1993, 1509 and references cited therein.
(14) Steffen, W. L.; Palenick, G. J . Inorg. Chem. 1976, 15, 2432.
(15) Trotter, J . In The Chemistry of the Carbon-Halogen Bond; Patai,
S., Ed.; Wiley: New York, 1973; Part I, p 50.
(11) Braunstein, P.; Hasselbring, R.; Tiripicchio, A.; Ugozzoli, F. J .
Chem. Soc., Chem. Commun. 1995, 37.

314 Organometallics, Vol. 15, No. 1, 1996
Falvello et al.
R ea ct ion of [P t (C6F 5)2(P h 2P CH P P h 2)]- w it h
C6F 5CN. In the preceding section we discussed the lack
of reactivity between [M(C6F5)2(Ph2PCHPPh2)]- and
C6F6, in which C-F bond cleavage does not take place.
However, some examples of C-F bond cleavage in
fluoroarenes C6F5X (especially those containing electron-
withdrawing substituents X such as CN or NO2) have
been reported in the literature.16 This cleavage is
always produced by attack on the arene by a strong
nucleophile through an aromatic nucleophilic substitu-
tion process. These aromatic nucleophilic substitutions
are favored by the presence of the CN or NO2 groups
due to their ability to stabilize the intermediate species.
In following that, we have attempted reactions between
[M(C6F5)2(Ph2PCHPPh2)]- (M ) Pd, Pt) and C6F5CN.
While the palladium derivative does not react,
[Pt(C6F5)2(Ph2PCHPPh2)]- reacts with C6F5CN to give
the neutral derivative Pt(C6F5)2[Ph2PCH(C6F4CN-4)-
PPh2] (10b) as a result of C-F bond cleavage at the para
position. This process is similar to that observed by
Vicente et al.16 in the reaction between C6F5CN and
phosphine ylides. The spectroscopic data are in accord
with the proposed structure (see Scheme 1). The IR
spectrum of 10b shows an intense absorption at 2222
cm-1, demonstrating the presence of the CtN group,
and the 1H NMR spectrum (see Table 1) shows the
methine P2CH(C6F4CN) resonance as a triplet at 6.53
ppm, which is strongly shifted downfield (2.5 ppm) with
respect to P2CH2 due to the high electron-withdrawing
ability of the C6F4CN group. The 31P{1H} NMR spec-
trum (Table 1) shows a single resonance with 195Pt
satellites also shifted to low field (up to 25 ppm) with
respect to the starting compund (see below for 19F NMR
discussion).
observe the same temperature dependence of the 19F
NMR spectra, so that there is no influence of the metal
center in the coalescence process. Similar behavior has
been found by us in the closely related complexes
M(C6F5)2[(PPh2)2CH(PPh2)] (M ) Pd, Pt).17 These data
are in contrast with the general assumption of the
hindered rotation of the cis-C6F5 groups around the
M-Cipso bond,18 but we have not found another sensible
explanation for our results.
Finally, the 19F NMR spectrum of complex 10b shows,
at room temperature, the presence of the resonances
corresponding to the organometallic C6F5 groups (AA′M-
M′X system) together with two other resonances: a
broad one at -130.20 ppm and a sharp doublet at
-130.92 ppm, corresponding to the C6F4CN group.
Upon cooling (-90 °C), the resonance of the organome-
tallic Fo splits into two signals and the resonances of
the C6F4CN group split into four well-resolved peaks
corresponding to the four chemically inequivalent F
atoms of the C6F4CN-4 unit. This seems to imply the
free rotation, at room temperature, of the C6F5 and C6F4-
CN-4 groups.
Con clu sion . The synthesis of the carbanionic de-
rivatives [M(C6F5)2(Ph2PCHPPh2)]- (M ) Pd, Pt) is
accomplished by deprotonation of [M(C6F5)2(Ph2PCH2-
t
PPh2)] with a strong base such as LDA or BuLi. These
complexes behave as strong nucleophiles and can be
alkylated, metalated, or halogenated chemoselectively
at the methanide carbon atom. The more nucleophilic
platinum derivative can also promote p-C-F bond
cleavage in functionalized fluoroarenes C6F5X (X ) CN)
as a result of an aromatic nucleophilic substitution
process. An important feature of these ligands is their
potential use as starting materials for the synthesis of
a variety of diphosphines. In this respect, the displace-
ment of the coordinated diphosphine from the metal
center is the final step of complete metal-mediated
synthesis of functionalized diphosphines. We are cur-
rently investigating this field.
19F NMR Sp ectr a of Com p lexes 2a -10b. All
complexes studied show similar characteristic features
(see Table 2): at room temperature they show three sets
of signals of relative intensity 2:1:2, corresponding to
Fo, Fp, and Fm and in keeping with the presence of two
equivalent C6F5 groups in which both halves of each
C6F5 group act as equivalent AA′MM′X systems (the
coordination plane is a symmetry plane on the NMR
time scale). At -90 °C the signal due to Fo is split into
two signals and the signal due to Fm is considerably
broadened, but not totally split. This shows that at low
temperatures the two halves of each C6F5 group are not
equivalent (AFMRX system), as expected for a static
structure (the coordination plane is not a symmetry
plane).
A sensible explanation for these facts, taking into
account the 1H and 31P{1H} NMR discussion (see above),
is the assumption of the free rotation of the cis-C6F5
groups around the M-Cipso bond at room temperature,
a process that will be stopped at low temperature. In
this respect, a temperature of -90 °C is needed for the
complete splitting of the Fo signal in complexes with
small groups at the methanide center (Me, Et, I, Br),
while for the heterobimetallic derivatives 5a -6b with
bulky substituents at the methanide center, the splitting
is observed at higher temperatures (around -30 °C, the
steric crowding seems to be important). Moreover, in
each pair of complexes Pd/Pt (i.e., 2a /2b or 5a /5b), we
Exp er im en ta l Section
All compounds were prepared under a dry nitrogen atmo-
sphere by using conventional vacuum line techniques. Sol-
vents were dried and distilled prior to use by standard
methods. Elemental analyses were carried out on a Perkin-
Elmer 240-B microanalyzer. IR spectra (4000-200 cm-1) were
recorded from Nujol mulls on a Perkin-Elmer 883 spectropho-
tometer. 1H NMR spectra were recorded at 300.13 MHz from
CDCl3 solutions (room temperature) on a Bruker ARX-300
spectrometer using the solvent signal as internal standard.
19F and 31P{1H} NMR spectra were recorded at 284.20 and
121.49 MHz, respectively, from CDCl3 (room temperature) or
CD2Cl2 solutions (19F at -90 °C) on a Bruker ARX-300
spectrometer and referenced to CFCl3 and H3PO4 (85%),
t
respectively. tert-Butyllithium (1.7 M BuLi solution in pen-
tane) and lithium diisopropylamide (LDA, 2.0 M solution in
heptane/THF/ethylbenzene) were obtained from commercial
sources. The starting compounds cis-M(C6F5)2(Ph2PCH2PPh2)
20
[M ) Pd (1a ), Pt (1b)]19 and ClAuPPh3 were prepared as
previously reported.
(17) Fornie´s, J .; Navarro, R.; Urriolabeitia, E. P. J . Organomet.
Chem. 1993, 452, 241.
(18) (a) Coco, S.; Espinet, P. J . Organomet. Chem. 1994, 484, 113.
(b) Albeniz, A. C.; Cuevas, J . C.; Espinet, P.; de Mendoza, J .; Prados,
P. J . Organomet. Chem. 1991, 410, 257 and references given therein.
(19) Uso´n, R.; Fornie´s, J .; Espinet, P.; Navarro, R.; Fortun˜o, C. J .
Chem. Soc., Dalton Trans. 1987, 2077.
(16) (a) Vicente, J .; Chicote, M. T.; Ferna´ndez-Baeza, J .; Ferna´ndez-
Baeza, A.; J ones, P. G. J . Am. Chem. Soc. 1993, 155, 794. (b) Vicente,
J .; Chicote, M. T.; Ferna´ndez-Baeza, J .; Ferna´ndez-Baeza, A. New J .
Chem. 1994, 18, 263.
(20) Bruce, M. I.; Nicholson, B. K.; Shawkataly, O. B. Inorg. Synth.
1989, 26, 325.

cis-[M(C6F5)2(Ph2PCHPPh2)]-
Organometallics, Vol. 15, No. 1, 1996 315
Syn th esis of cis-M(C6F 5)2[P h 2P CH(Me)P P h 2] [M ) P d
(2a ), P t (2b)]. To a solution of 1a (0.315 g, 0.382 mmol) in 10
mL of dry THF was added LDA (0.23 mL, 0.46 mmol). A clear
yellow solution was obtained instantaneously. This solution
was stirred for 5 min at room temperature, and then MeI (0.12
mL, 1.9 mmol) was added. The resulting pale yellow solution
was stirred overnight and the solvent was evaporated to
dryness; the residue was extracted with CH2Cl2 (30 mL) and
filtered. Evaporation of the resulting colorless solution to
small volume (≈2 mL) and addition of iPrOH (10 mL) produced
the precipitation of a white solid, which was filtered, washed
with n-hexane (10 mL), dried in vacuo, and identified by NMR
spectroscopy as a mixture of 2a and 3a (0.25 g). Compound
2a could be obtained in pure form by recrystallization from
CH2Cl2/n-hexane: 0.211 g (65% yield). Anal. Calcd for
cis-Pt(C6F5)2[Ph2PCH(AgPPh3)PPh2] (6b) was obtained simi-
larly, as a white solid, starting from 1b (0.250 g, 0.274 mmol),
tBuLi (0.19 mL, 0.32 mmol), and O3ClOAgPPh3 (0.129 g, 0.274
mmol). The product was recrystallized from CH2Cl2/n-hexane,
giving 6b as a CH2Cl2 solvate: 0.155 g (44% yield). The
amount of CH2Cl2 was determined by H NMR. Anal. Calcd
for C55H36P3F10PtAg‚0.3CH2Cl2 (1308.23): C, 50.77; H, 2.82.
Found: C, 50.51; H, 3.06.
Rea ction of cis-[P t(C6F 5)2(P h 2P CHP P h 2)]- w ith Cl2. A
solution of 1b (0.120 g, 0.131 mmol) in 15 mL of dry THF at
room temperature was treated with tBuLi (0.10 mL, 0.17
mmol) and subsequently with a solution of Cl2 in CCl4 (0.60
mL, 0.14 mmol). The reaction mixture was stirred for 6 h at
room temperature and then evaporated to dryness. The
1
residue was extracted with CH
2Cl2 (30 mL) and filtered, and
C
38H24P2F10Pd (838.94): C, 54.40; H, 2.88. Found: C, 54.11;
H, 2.77.
cis-Pt(C6F5)2[Ph2PCH(Me)PPh2] (2b) was obtained in
the solution was evaporated to dryness. The resulting white
residue was washed with n-hexane (10 mL) and dried in vacuo,
affording 0.090 g of a white solid that was identified by NMR
spectroscopy as a mixture of 1b and 7b in a 9:1 molar ratio.
Syn th esis of cis-P t(C6F 5)2[P h 2P CH(Br )P P h 2] (8b). (a)
To a solution of 1b (0.250 g, 0.274 mmol) in 20 mL of dry THF
was added LDA (0.17 mL, 0.34 mmol), and after 5 min of
stirring at room temperature, BrC6F5 (0.18 mL, 1.37 mmol)
was added. The resulting pale yellow solution was stirred for
24 h at room temperature and then refluxed for an additional
2 h. After cooling, the solvent was evaporated to dryness, and
the remaining residue was extracted with anhydrous Et2O (20
mL). The solid in suspension was filtered, the ether solution
was evaporated to a small volume (≈2 mL), and n-hexane (20
mL) was added, resulting in the precipitation of a white solid
(8b), which was filtered and vacuum-dried: 0.123 g (45%
yield).
a
t
similar way: 1b (0.25 g, 0.27 mmol) was reacted with BuLi
(0.19mL, 0.32 mmol) and MeI (0.17 mL, 2.7 mmol) to give a
mixture of 2b and 3b (0.20 g), from which 2b [0.182 g (72%
yield)] could be obtained in pure form after recrystallization.
Anal. Calcd for C38H24P2F10Pt (927.63): C, 49.20; H, 2.60.
Found: C, 48.93; H, 2.51.
Rea ction of cis-[M(C6F 5)2(P h 2P CHP P h 2)]- (M ) P d , P t)
w ith EtI. To a solution of 1a (0.250 g, 0.303 mmol) in 10 mL
of dry THF was added LDA (0.2 mL, 0.4 mmol). After 5 min,
EtI (0.12 mL, 1.5 mmol) was added, and the resulting pale
yellow solution was stirred overnight at room temperature.
The solvent was then evaporated to dryness, and the residue
was extracted with CH2Cl2 (30 mL) and filtered. The resulting
colorless solution was evaporated to dryness, and the residue
was treated with PrOH (10 mL), giving a white solid (0.215
g) identified by NMR as a mixture of 1a and 4a in a 1:1.2 molar
ratio. The reaction between 1b (0.250 g, 0.274 mmol), BuLi
(0.19 mL, 0.32 mmol), and EtI (0.22 mL, 2.74 mmol), carried
out similarly to that for 1a , also gives a white solid (0.172 g),
identified as a mixture of 1b and 4b (1:1.4 molar ratio).
(b) To a solution of 1b (0.250 g, 0.274 mmol) in 15 mL of
i
t
dry THF was added BuLi (0.17 mL, 0.30 mmol), and after 5
min of stirring at room temperature, Br2 in CCl4 (1.47 mL,
0.28 mmol) was added. The resulting pale yellow solution was
stirred for 6 h at room temperature and then evaporated to
dryness, and the residue was extracted with 20 mL of CH2-
Cl2. The remaining white solid was filtered and the clear
solution was evaporated to a small volume (≈2 mL). Addition
of Et2O (5 mL) and hexane (15 mL) produced the precipitation
of 8b: 0.20 g (74% yield). Anal. Calcd for C37H21F10P2BrPt
(992.50): C, 44.77; H, 2.13. Found: C, 44.90; H, 2.48.
Syn th esis of cis-M(C6F 5)2[P h 2P CH(I)P P h 2] [M ) P d
(9a ), P t (9b)]. (a) To a solution of 1a (0.250 g, 0.303 mmol)
in 15 mL of dry THF was added LDA (0.20 mL, 0.40 mmol),
and subsequently IC6F5 was added (0.40 mL, 3.0 mmol). The
resulting yellow solution was stirred at room temperature for
6 h and then refluxed for an additional 3 h and evaporated to
dryness. The residue was extracted with 20 mL of CH2Cl2 and
filtered, and the solution was evaporated to a small volume (2
mL). The addition of n-hexane (20 mL) produced the precipi-
tation of a yellow orange solid (9a ), which was filtered and
air-dried: 0.151 g (53% yield).
(b) To a solution of 1a (0.200 g, 0.242 mmol) in 15 mL of
dry THF were added tBuLi (0.15 mL, 0.25 mmol) and,
subsequently, I2 (0.063 g, 0.25 mmol). The resulting yellow
solution was stirred at room temperature for 6 h and then
evaporated to dryness. The residue was extracted with 20 mL
of CH2Cl2 and filtered, and the solution was evaporated to a
small volume (≈2 mL). The addition of n-hexane (20 mL)
produced the precipitation of 9a : 0.169 g (74% yield). Anal.
Calcd for C37H21F10P2IPd (950.80): C, 46.74; H, 2.22. Found:
C, 46.45; H, 2.06.
t
Complexes 4a and 4b could not be obtained in analytically
pure form due to the presence of the starting products.
Attempts to separate these mixtures by fractional crystalliza-
tion failed, always giving mixtures with the same (or nearly
the same) composition as that of the starting mixture.
Syn th esis of cis-M(C6F 5)2[P h 2P CH(M′P P h 3)P P h 2] [M′
) Au , M ) P d (5a ), P t (5b); M′ ) Ag, M ) P d (6a ), P t (6b)].
To a solution of 1a (0.250 g, 0.303 mmol) in 15 mL of dry THF
at room temperature was added LDA (0.2 mL, 0.4 mmol),
giving a yellow solution. After 5 min of stirring at room
temperature, ClAuPPh3 (0.150 g, 0.303 mmol) was added and
the resulting pale yellow solution was stirred for 1 h. The
solvent was then evaporated to dryness and the residue was
treated with 20 mL of anhydrous Et2O. The small quantity
of the remaining solid was filtered, and the resulting solution
was evaporated to a small volume (≈2 mL). Addition of
n-hexane (20 mL) produced the precipitation of a pale yellow
solid (5a ), which was filtered and dried in vacuo: 0.388 g (87%
yield). Anal. Calcd for C55H36P3F10PdAu (1283.16): C, 51.48;
H, 2.83. Found: C, 51.37; H, 3.02.
cis-Pt(C6F5)2[Ph2PCH(AuPPh3)PPh2] (5b) was obtained simi-
t
larly, as a white solid, by using 1b (0.250 g, 0.274 mmol), -
BuLi (0.19 mL, 0.32 mmol), and ClAuPPh3 (0.135 g, 0.274
mmol): 0.262 g (70% yield). Anal. Calcd for C55H36P3F10PtAu
(1371.85): C, 48.15; H, 2.64. Found: C, 48.06; H, 2.50.
The complex cis-Pt(C6F5)2[Ph2PCH(I)PPh2] (9b) was ob-
tained, as a yellow crystalline solid, by following method b and
starting from 1b (0.250 g, 0.274 mmol), BuLi (0.19 mL, 0.32
cis-Pd(C6F5)2[Ph2PCH(AgPPh3)PPh2] (6a ) was obtained simi-
larly by starting from 1a (0.250 g, 0.303 mmol), LDA (0.20
mL, 0.40 mmol), and O3ClOAgPPh3 (0.142 g, 0.303 mmol),
resulting in a white solid. The product was recrystallized from
CH2Cl2/n-hexane, giving 6a as a CH2Cl2 solvate: 0.210 g (58%
yield). The amount of CH2Cl2 was determined by 1H NMR.
Anal. Calcd for C55H36P3F10PdAg‚0.3CH2Cl2 (1219.54): C,
54.46; H, 3.02. Found: C, 54.38; H, 3.17.
t
mmol), and I2 (0.076 g, 0.30 mmol): 0.238 g (84% yield). Anal.
Calcd for
C37H21F10P2IPt (1039.49): C, 42.75; H, 2.03.
Found: C, 42.61; H, 1.99.
Syn th esis of cis-P t(C6F 5)2[P h 2P CH(p-C6F 4CtN)P P h 2]
(10b). To a solution of 1b (0.250 g, 0.274 mmol) in 15 mL of

316 Organometallics, Vol. 15, No. 1, 1996
Falvello et al.
Ta ble 5. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 9b
dry THF was added LDA (0.2 mL, 0.4 mmol). The resulting
yellow solution was stirred for 15 min at room temperature
and then treated with C6F5CtN (0.35 mL, 2.7 mmol). The
red solution obtained was refluxed for 3.5 h and then cooled
and evaporated to dryness. The residue was extracted with
CH2Cl2 (20 mL), filtered (a small quantity of a gray solid was
discarded), and again evaporated to dryness. A new extraction
with anhydrous Et2O (20 mL) produced the precipitation of a
small amount of starting product 1b which was also discarded.
The clear ether solution was evaporated to dryness and the
oily residue was treated with n-hexane, giving a pale orange
solid that was filtered and dried in vacuo. Subsequent
recrystallization from CHCl3/n-hexane afforded white crystals
of 10b: 0.15 g (50% yield). Anal. Calcd for C44H21F14P2NPt
(1086.67): C, 48.63; H, 1.94; N, 1.29. Found: C, 48.52; H, 2.01;
N, 1.44.
X-r a y Da ta Collection , Str u ctu r e Deter m in a tion , a n d
R efin em en t for [P t (C6F 5)2(P h 2P CH IP P h 2)]‚C5H 12 (9b ‚
C5H12). A pale yellow crystal of 9b‚C5H12 (approximate
dimensions 0.47 × 0.41 × 0.40) was mounted on a glass fiber
and covered with epoxy. The crystallographic data are sum-
marized in Table 5. All diffraction measurements were made
at room temperature with an automated four-circle diffracto-
meter.21 Although the lattice parameters emerged from
routine procedures without difficulty, axial photographs were
taken of the a-, b-, and c-axes to verify the lattice dimensions.
The diffraction spots were broad and poorly shaped. Unit cell
dimensions were determined from 25 centered reflections in
the range 21.9 e 2θ e 31.6°. For intensity data collection, ω
scans were used with ∆ω ) 1.25 + 0.35 tan θ. Three check
reflections remeasured after every 3 h of beam time showed a
decay of not more than 2% over the period of data collection.
An empirical absorption correction was based on 518 azi-
muthal scan data (maximum and minimum transmission
coefficients were 1.000 and 0.769).22 The structure was solved
and developed by Patterson and Fourier methods. All non-
hydrogen atoms were assigned anisotropic displacement pa-
identification code
empirical formula
formula weight
temperature (K)
wavelength (Å)
crystal system
[Pt(C6F5)2(Ph2PCHIPPh2)]‚C5H12
C42H33F10IP2Pt
1111.61
293(2)
0.710 73
monoclinic
space group
P21/m
unit cell dimensions
a ) 10.011(7) Å, R ) 90°
b ) 20.038(9) Å, â ) 106.84(4)°
c ) 10.559(5) Å, γ ) 90°
2027(2)
volume (Å3)
Z
2
density (calculated) (Mg/m3)
absorption coefficient (mm-1
F(000)
1.821
4.377
1072
)
crystal size (mm)
θ range for data collection
(deg)
0.47 × 0.41 × 0.40
2.02-24.97
index ranges
0 e h e 11, 0 e k e 23,
-12 e l e 12
3899
reflections collected
independent reflections
absorption correction
max and min transmission
refinement method
3671 (Rint ) 0.0158)
psi
1.000 and 0.769
full-matrix least-squares on F2
3671/0/308
data/restraints/parameters
goodness-of-fit on F2
1.060
final R indices [I > 2σ(I)]
R indices (all data)
R1 ) 0.0298, wR2 ) 0.0745
R1 ) 0.0376, wR2 ) 0.0790
0.750 and -0.990
largest diff. peak and hole
(e Å-3
)
for C-C bonds, and the displacement parameters for the atoms
of both terminal C2H5 groups are large and quite anisotropic.
The hydrogen atoms of this group were omitted from the
model. The data to parameter ratio in the final refinement
was 12.7. The structure was refined to Fo2, and all reflections
were used in the least-squares calculations.23
rameters. The hydrogen atoms were located in
a final
Ack n ow led gm en t. We thank the Direccio´n General
de Investigacio´n Cient´ıfica y Te´cnica (Spain) for finan-
cial support (Projects PB92-0360 and PB92-0364).
difference Fourier map and refined with isotropic thermal
displacement parameters. Five atomic sites in an interstitial
zone, with each mean atomic position lying on a crystal-
lographic mirror, were modeled as a C5H12 molecule with
anisotropic displacement parameters for the five carbon atoms.
The parameters for the interstitial pentane moiety, not
surprisingly, showed signs of either static or dynamic disorder.
That is, the bond distances are shorter than the known values
Su p p or tin g In for m a tion Ava ila ble: Tables of complete
bond distances and angles, anisotropic thermal parameters,
and hydrogen coordinates for 9b (7 pages). Ordering informa-
tion is given on any current masthead page.
OM950457V
(21) Diffractometer control program: CAD4.PC Version 1.5c, Delft
Instruments X-ray Diffraction bv, Delft, The Netherlands, 1994.
(22) Data were processed on a local area VAXCluster (VMS V5.5-2)
with the commercial package SHELXTL-Plus Release 4.21/V, Siemens
Analytical X-ray Instruments, Inc., Madison, WI, 1990.
(23) (a) Sheldrick, G. M. Shelxl-93: Fortran-77 program for the
refinement of crystal structures from diffraction data, University of
Go¨ttingen, 1993. (b) Sheldrick, G. M., in preparation.