Reactivity of [M(C∧P)(S2CNMe2)] [M = Pt, Pd; C∧P = CH2-C6H4-P(o-tolyl)2-κC,P] toward mercury(II) carboxylates. X-ray molecular structures of [Pt(C∧P)-(S2CNMe2)(O2

Article abstract of DOI:10.1021/om990856g

The reaction of the complex [Pt{CH₂-C₆H₄-P(o-tolyl) ₂-κC,P}(S₂CNMe₂)] (A) with an equimolar amount of Hg(O₂CR)₂ (R = CH₃, CF₃) gives the binuclea

Full text of DOI:10.1021/om990856g

Organometallics 2000, 19, 1107-1114
1107
Rea ctivity of [M(C∧P )(S2CNMe2)] [M ) P t, P d ; C∧P )
CH2-C6H4-P (o-tolyl)2-KC,P ] tow a r d Mer cu r y(II)
Ca r boxyla tes. X-r a y Molecu la r Str u ctu r es of [P t(C∧P )-
(S2CNMe2)(O2CCF 3)Hg(O2CCF 3)] a n d [P d (S2CNMe2)-
{µ-P (o-tolyl)2-C6H4-CH2-}(µ-O2CCH3)Hg(O2CCH3)]
J uan Fornie´s,* Antonio Mart´ın, Violeta Sicilia, and Pablo Villarroya
Departamento de Quı´mica Inorga´nica, Instituto de Ciencias de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received October 25, 1999
The reaction of the complex [Pt{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (A) with an
equimolar amount of Hg(O2CR)2 (R ) CH3, CF3) gives the binuclear compounds OC-6-23
[Pt(C∧P)(S2CNMe2)(O2CR)Hg(O2CR)] [R ) CH3 (1), CF3 (2)] containing a Pt-Hg covalent
bond. These compounds result from the cis oxidative addition of the mercury(II) carboxylate
to complex A. A concerted mechanism involving a platinum to mercury donor bond
intermediate is proposed. The reaction of the complex [Pd{CH2-C6H4-P(o-tolyl)2-κC,P}(S2-
CNMe2)] (B) with Hg(O2CR)2 (R ) CH3, CF3) in a 1:1 molar ratio leads to the corresponding
binuclear complexes [Pd(S2CNMe2){µ-P(o-tolyl)2-C6H4-CH2-}(µ-O2CR)Hg(O2CR)] [R ) CH3
(3), CF3 (4)] with the bidentate C∧P ligand acting as an unusual bridging group. Compounds
3 and 4 come from a transmetalation process without the complete transference of the ligand
from Pd to Hg.
In tr od u ction
complexes [M{CH2-C6H4-P(o-tolyl)2-κC,P}(S2C-Z)] [M
) Pt, Pd; Z ) NMe2, OEt], and we have demonstrated
their ability to form a donor-acceptor Pt-M′ bond [M′
) Hg, Ag, Au]. For M′ ) Ag, Au, there are polynuclear
compounds containing not only PtfM′ interactions but
also S-M′ bonds.7 For M′ ) Hg, [{Pt{CH2-C6H4-P(o-
tolyl)2-κC,P}(S2C-Z)HgX(µ-X)}2] [Z ) NMe2, OEt; X )
Br, I] compounds were formed by reaction of [Pt{CH2-
C6H4-P(o-tolyl)2-κC,P}(S2C-Z)] [Z ) NMe2, OEt] with
HgX2, in which the platinum fragments were connected
to mercury through unsupported PtfHg donor-accep-
tor bonds.6b These facts indicate that in these kind of
complexes the metal center (Pt) acts as a Lewis base
toward suitable Lewis acids.
Metal-metal bonding in heteronuclear complexes
containing d8 and d10 metal ions has been known for
some years.1 In our group much work has been carried
out on the synthesis of heteronuclear PtfAg2 and
PtfHg3 compounds using mono- or binuclear anionic
pentahalophenyl complexes of Pt(II) as Lewis bases.
There has been a progressive increase in the use of
monoanionic chelating ligands in organometallic chem-
istry4 since these ligands enhance the reactivity of the
metal center, stabilize a variety of metal oxidation
states, control the metal stereochemistry, and do not
readily dissociate from the metal, as this would require
the breaking of a σ-metal-carbon bond. Metal com-
plexes based on such ligands are now becoming more
and more important in homogeneous catalysis.5
To extend the study of the reactivity of [M{CH2-
C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] [M ) Pt (A), Pd (B)]
compounds toward other mercury(II) derivatives, we
decided to examine the behavior of such compounds
toward Hg(O2CCH3)2 and Hg(O2CCF3)2. As a result of
this work, in this paper we report the synthesis,
structural characterization, and NMR studies of new
mixed Pt-Hg and Pd-Hg complexes.
We have previously described the synthesis of several
complexes containing the monoanionic chelating ligand
{CH2-C6H4-P(o-tolyl)2-κC,P},6 such as the neutral
(1) (a) Coffey, E.; Lewis, J .; Nyholm, R. S. J . Chem. Soc. 1964, 1741.
(b) Kuyper, J .; Vrieze, K. J . Organomet. Chem. 1976, 107, 129.
(2) (a) Uso´n, R.; Fornie´s, J . J . Adv. Organomet. Chem. 1988, 28,
219. (b) Uso´n, R.; Fornie´s, J . Inorg. Chim. Acta 1992, 198-200, 165.
(3) Uso´n, R.; Fornie´s, J .; Falvello, L. R.; Ara I.; Uso´n, I. Inorg. Chim.
Acta 1993, 212, 105.
(4) (a) Maestri, M.; Sandrini, D.; von Zelewsky, A.; Deuschel-
Cornioley, C. Inorg. Chem. 1991, 30, 2476. (b) Maestri, M.; Deuschel-
Cornioley, C.; von Zelewsky, A. Coord. Chem. Rev. 1991, 111, 117. (c)
Gruter, G.-J . M.; van Klink, G. P. M.; Akkerman, O. S.; Bickelhaupt,
F. Chem. Rev. 1995, 95, 2405. (d) van der Boom, M. E.; Lion, S.-Y.;
Shimon, L. J . W.; Ben-David, Y.; Milstein, D. Organometallics 1996,
15, 2562. (e) Rybtchinski, B.; Vigalok, A.; Ben-David, Y.; Milstein, D.
J . Am. Chem. Soc. 1996, 118, 12406. (f) van der Boom, M. E.; Kraatz,
H.-B.; Ben-David, Y.; Milstein, D. J . Chem. Soc., Chem. Commun. 1996,
2167.
(5) (a) Herrmann, W. A.; Brossmer, C.; O¨ fele, K.; Reisinger, C. P.;
Priermeier, T.; Beller, M.; Fischer, H. Angew. Chem., Int. Ed. Engl.
1995, 34, 1844. (b) Beller, M.; Fischer, H.; Herrmann, W. A.; O¨ fele,
K.; Brossmer, C. Angew. Chem., Int. Ed. Engl. 1995, 34, 1848. (c) Shaw,
B. L.; Perera, S. D.; Staley, E. A. J . Chem. Soc., Chem. Commun. 1998,
1361. (d) Ohff, M.; Ohff, A.; van der Boom, M. E.; Milstein, D. J . Am.
Chem. Soc. 1997, 119, 11687.
(6) (a) Fornie´s, J .; Mart´ın, A.; Navarro, R.; Sicilia, V.; Villarroya, P.
Organometallics 1996, 15, 1826. (b) Falvello, L. R.; Fornie´s, J .; Mart´ın,
A.; Navarro, R.; Sicilia, V.; Villarroya, P. Inorg. Chem. 1997, 36, 6166.
(7) Fornie´s, J .; Mart´ın, A.; Navarro, R.; Sicilia, V.; Villarroya, P.;
Orpen, A. G. J . Chem. Soc., Dalton Trans. 1998, 3721.
10.1021/om990856g CCC: $19.00 © 2000 American Chemical Society
Publication on Web 02/24/2000

1108 Organometallics, Vol. 19, No. 6, 2000
Fornie´s et al.
) 14.4 Hz, CH2), 38.23 (s, Mecarbamate), 38.55 (s, Mecarbamate),
120-160 (m, C6H4) 175.66 (s, CO2), 176.51 (s, CO2), 205.16 (s,
CS2).
X ) F (4). This complex was prepared in a similar way to
3 with [Pd{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (B) (0.1537
g, 0.290 mmol) and Hg(O2CCF3)2 (0.1237 g, 0.290 mmol).
Yield: 0.1334 g, 59.72% (Found: C, 35.44; H, 2.80; N, 1.53.
Exp er im en ta l Section
Elemental analyses were determined using a Perkin-Elmer
240-B microanalyzer. IR spectra were recorded on a Perkin-
Elmer 599 spectrophotometer (Nujol mulls between polyeth-
ylene plates in the range 4000-200 cm-1). NMR spectra were
recorded on either a Varian XL-200 or a Varian Unity 300
NMR spectrometer using the standard references. [Pt{CH2-
C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (A)6a and [Pd{CH2-C6H4-
P(o-tolyl)2-κC,P}(S2CNMe2)] (B)6b were prepared as described
elsewhere.
C
28F6H26HgNO4PPdS2 requires C, 35.16; H, 2.74; N, 1.46). IR
(ν/cm-1): 442m, 461m, 480s, 501m, 523m, 536m, 551w, 573m,
751s, 760s, 787s, 818s, 968m ν(C-S), 1567vs ν(C-N) (Me2-
NCS2-), 1143vs, 1168vs, 1189vs, 1676vs, 1709vs (CF3CO2-).
1H NMR (CD2Cl2, 188 K) δ: 1.47 (s, CH3 C∧P), 1.89 (s, CH3 C∧P),
[P t {CH 2-C6H 4-P (o-t olyl)2-KC,P }(S2CNMe2)(O2CCX3)-
Hg(O2CCX3)] [X ) H (1), F (2)]. X ) H (1). To a cooled
solution of [Pt{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (A)
(0.1950 g, 0.3151 mmol) in CHCl3 (25 mL) at -20 °C was added
Hg(O2CCH3)2 (0.1004 g, 0.3151 mmol). The solution, which
immediately acquired a bright yellow color, was stirred for 2
h at this temperature. It was then filtered through Celite and
evaporated to dryness. Addition of diethyl ether to the residue
at -20 °C afforded a yellow solid, 1 (0.2207 g, 74.7%) (Found:
C, 36.17; H, 3.49; N, 1.51. C28H32HgNO4PPtS2 requires C,
35.88; H, 3.44; N, 1.49). IR (ν/cm-1): 458m, 476m, 488m, 508w,
523m, 535m, 553m, 566m, 583m, 671m, 756s, 974m ν(C-S),
1538 ν(C-N) (Me2NCS2-), 1566m, 1576m (CH3CO2-). 1H NMR
(CDCl3, 223 K) δ: 1.91 (s, CH3 acetate), 1.97 (s, CH3 C∧P), 2.05
(s, CH3 C∧P), 2.11 (s, CH3 acetate), 2.96 (s, CH3 carbamate),
3.12 (s, CH3 carbamate), 3.90 (νA, 2J PtH ) 95.9 Hz, 2J HH ) 14.3
Hz, CH2), 4.34 (νB, 2J PtH ) 73.3 Hz, 2J HH ) 14.3 Hz, CH2), 6.49
2
3.05 (d, J HH ) 11.0 Hz, 1H, CH2), 3.12 (s, 6H, CH3 carbamate),
2
3.77 (d, J HH ) 11.0 Hz, 1H, CH2), 6.7-7.7 (m, 11H, C6H4),
3
3
8.87 (dd, H6, J PH ) 16.9 Hz, J H6H5 ) 6.1 Hz). 19F NMR δ:
-73.10 (s), -73.57 (s).
X-r a y Cr ysta l Str u ctu r e Deter m in a tion s of [P t {CH2-
C 6 H 4 -P (o-t o ly l)2 -KC,P }(S 2 C N Me 2 )(O 2 C C F 3 )H g (O 2 C -
CF3)].0.5Me2CO (2) an d [P d(S2CNMe2){µ-P (o-tolyl)2-C6H4-
CH2-}(µ-O2CMe)Hg(O2CMe)].H2O (3). Suitable crystals of
2‚0.5Me2CO were obtained by slow diffusion of n-pentane in
Me2CO/CH2Cl2 solutions of complex 2 at 5 °C. Suitable crystals
of 3‚H2O were obtained by slow diffusion of n-hexane in CH2-
Cl2 solutions of complex 3 at 5 °C.
Crystal data and other details of the structure analyses are
presented in Table 1. Crystals were fixed on top of glass or
quartz fibers and mounted on diffractometers. Unit cell
constants were determined from 60 accurately centered reflec-
tions with 25.9° < 2θ < 35.4° for 2‚0.5Me2CO and 60 reflections
in the range 24° < 2θ < 26° for 3‚H2O. Data were collected
using ω/θ scans for 2‚0.5Me2CO and ω scans for 3‚H2O. Three
check reflections were measured at regular intervals, and no
loss of intensity was observed in either case. The positions of
the heavy atoms were determined from the Patterson maps.
The remaining atoms were located in successive difference
Fourier syntheses. H atoms were added at calculated positions
(C-H ) 0.96 Å) with isotropic displacement parameters
assigned as 1.2 times the equivalent isotropic U’s of the
corresponding C atoms. For 2‚0.5Me2CO, there are two mol-
ecules of the platinum complex in the asymmetric part of the
unit cell. Three of the four CF3 groups of the trifluoroacetate
ligands are badly disordered. This disorder has been modeled
assigning two sets of positions for the fluorine atoms of each
CF3 group (0.5/0.5 occupancy). The thermal parameter of the
opposite fluorine atoms have been constrained to be the same.
The C-F distances have been restrained for all the CF3 groups.
The thermal parameters of the atoms of the acetone solvent
molecule have been constrained to be the same. The inter-
atomic distances in the solvent molecule have been restrained.
For 2‚0.5Me2CO a final difference electron density maps
showed one peak above 1 e Å-3 (1.37; largest diff hole -1.45)
lying 1.16 Å from the mercury atom. For 3‚H2O a final
difference electron density map showed no peaks above 1 e
Å-3 (max 0.69; largest diff hole -0.81). All calculations were
carried out using the program SHELXL-93.8
3
3
(dd, H6′, J PH ) 13.2 Hz, J H6′H ) 7.6 Hz), 7.0-7.5 (m, 10H,
5′
3
3
4
C6H4), 8.22 (ddd, H6, J PH ) 17.5 Hz, J H6H5 ) 7.7 Hz, J H6H4
) 1.8 Hz). 13C{1H} δ: 10.03 (s, CH2), 20.95 (d, J PC ) 7.1 Hz,
3
MeC∧P), 23.16 (s, Meacetate), 23.51 (d, 3J PC ) 3.1 Hz, MeC∧P), 24.31
(s, Meacetate), 37.45 (s, Mecarbamate), 39.83 (s, Mecarbamate), 120-
160 (m, C6H4) 176.80 (s, CO2), 177.29 (s, CO2), 205.58 (s, CS2).
X ) F (2). This complex was prepared in a similar way to
1 with [Pt{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (A) (0.2002
g, 0.3235 mmol) and Hg(O2CCH3)2 (0.138 g, 0.3235 mmol).
Yield: 0.2775 g, 82% (Found: C, 32.51; H, 2.55; N, 1.39.
C28F6H26HgNO4PPtS2 requires C, 32.17; H, 2.50; N, 1.34). IR
(ν/cm-1): 456m, 477m, 487m, 503w, 525m, 535m, 553m, 568m,
584m, 753m, 766m, 791s, 845s, 970m ν(C-S), 1556 ν(C-N)
(Me2NCS2-), 1151vs, 1192vs, 1667vs, 1684vs (CF3CO2-). 1H
NMR (CDCl3, 223 K) δ: 1.99 (s, CH3 C∧P), 2.01 (s, CH3 C∧P),
2
2.99 (s, CH3 carbamate), 3.19 (s, CH3 carbamate), 4.10 (νA, J PtH
)
102.5 Hz, 2J HH ) 14.2 Hz, CH2), 4.44 (νB, 2J PtH ) 78.0 Hz, 2J HH
3
3
) 14.2 Hz, CH2), 6.50 (dd, H6′, J PH ) 13.4 Hz, J H6′H ) 7.6
5′
3
Hz), 7.1-7.6 (m, 10H, C6H4), 8.06 (dd, H6, J PH ) 17.9 Hz,
3J H6H5 ) 7.3 Hz). 19F NMR δ: -73.38 (s), -74.16 (s). 13C{1H}
δ: 12.65 (s, CH2), 20.80 (s, MeC∧P), 23.46 (s, MeC∧P), 37.38 (s,
Mecarbamate), 39.89 (s, Mecarbamate), 110-160 (m, C6H4, CF3)
2
2
160.57 (q, J CF ) 36.22 Hz, CO2), 162.34 (q, J CF ) 36.22 Hz,
CO2), 203.81 (s, CS2).
[P d(S2CNMe2){µ-P (o-tolyl)2-C6H4-CH2-}(µ-O2CCX3) Hg-
(O2CCX3))] [X ) H (3), F (4)]. X ) H(3). To a solution of [Pd-
{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (B) (0.1500 g, 0.283
mmol) in CHCl3 (15 mL) was added Hg(O2CCH3)2 (0.090 g,
0.283 mmol), and the solution immediately acquired a yellow-
orange color. The mixture was stirred for 40 min until total
solution of the Hg(O2CCH3)2 and was then filtered through
Celite. Evaporation of the solvent to dryness and addition of
diethyl ether to the residue yielded 3 as a bright yellow solid
Resu lts
Rea ctivity of [M{CH2-C6H4-P (o-tolyl)2-KC,P }-
(S2CNMe2)] [M ) P t (A), P d (B)] w ith Mer cu r y(II)
Ca r boxyla tes. Syn th esis of Com p lexes 1-4. Com-
plexes [M(C∧P)(S2CNMe2)] [M ) Pt (A), Pd (B)] react
in chloroform with an equimolar amount of mercury-
(II) carboxylates, Hg(O2CR)2 (R ) CH3, CF3), to afford
complexes 1-4, as indicated in Scheme 1. All complexes
are obtained in good yield and are stable for a long time
in the solid state. However, in CHCl3 solution, only
(0.1890 g, 78.7%) (Found: C, 39.27; H, 3.92; N, 1.64. C28H32
-
HgNO4PPdS2 requires C, 39.63; H, 3.80; N, 1.65). IR (ν/cm-1):
444m, 463m, 480s, 495m, 523m, 537m, 550w, 571m, 756s, sh,
969m ν(C-S), 1564 ν(C-N) (Me2NCS2-), 1611m, 1626m
(CH3CO2-). 1H NMR (CD2Cl2, 253 K) δ: 1.37 (s, CH3 acetate),
1.57 (s, CH3 C∧P), 1.90 (s, CH3 C∧P), 2.01 (s, CH3 acetate), 2.98 (d,
2J HH ) 11.2 Hz, 1H, CH2), 3.15 (s, CH3 carbamate), 3.22 (s,
2
CH3 carbamate), 3.62 (d, J HH ) 11.2 Hz, 1H, CH2), 6.8-7.7 (m,
3
11H, C6H4), 9.06 (d, H6, J PH ) 16.5 Hz). 13C{1H} δ: 22.32 (s,
(8) Sheldrick, G. M. SHELXL-93, a program for crystal structure
determination; University of Go¨ttingen: Germany, 1993.
MeC∧P, acetate), 23.53 (s, MeC∧P), 23.77 (s, Meacetate), 31.64 (d, 3J PC

Reactivity of [M(C∧P)(S2CNMe2)]
Organometallics, Vol. 19, No. 6, 2000 1109
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t P a r a m eter s for 2‚0.5Me2CO a n d 3‚H2O
2‚0.5Me2CO
3‚H2O
empirical formula
fw
C
30H31F6HgNO4.5PPtS2
C28H34HgNO5PPdS2
866.64
2164.66
unit cell dimens
a (Å)
b (Å)
14.191(12)
14.937(12)
19.488(15)
111.53(5)
102.65(4)
101.93(4)
3556.9(13), 4
0.71073
8.012(1)
35.069(5)
11.355(1)
90
101.31(1)
90
3128.5(7), 4
0.71073
200(2)
c (Å)
R (deg)
â (deg)
γ (deg)
volume (Å3), Z
wavelength (Å)
temperature (K)
radiation
cryst syst
space group
173(2)
graphite-monochromated Mo KR
triclinic
P1h
8.470
monoclinic
P2(1)/n
5.697
abs coeff (mm-1
)
transmission factors
abs corr
diffractometer
2θ range for data collect. (deg)
no. of reflns collected
no. of ind reflns
refinement method
goodness-of-fit on F2
final R indices (I > 2σ(I))a
R indices (all data)
0.951, 0.742
ψ scans
Siemens STOE/AED2
4-50 (-h, (k, (l)
13 065
0.809, 0.566
ψ scans
Siemens STOE/AED2
4-50 (+h, +k, (l)
6162
12 475 (R(int) ) 0.0314)
4875 (R(int) ) 0.0388)
full-matrix least-squares on F2
1.073
1.102
R1 ) 0.0427, wR2 ) 0.0838
R1 ) 0.0756, wR2 ) 0.1189
R1 ) 0.0297, wR2 ) 0.0580
R1 ) 0.0484, wR2 ) 0.0870
R1 ) ∑||Fo| - |Fc||/∑|Fo|; wR2 ) [∑w(Fo - Fc )2/∑w(Fc2)2 ]1/2. Goodness-of-fit ) [∑w(Fo - Fc2)2/(nobs - nparam)]1/2. w ) [σ2(Fo) + (g1P)2
a
2
2
2
+ g2P]-1; P ) [max(Fo2; 0) + 2Fc2]/3.
Sch em e 1
complex 1 is unstable at room temperature and has to
be handled at a low temperature (-20 °C) to avoid its
decomposition.
Elemental analyses revealed the same stoichiometry
for all compounds. However NMR data and the X-ray
studies on complexes 2 and 3 indicated important
structural differences between the platinum (1 and 2)
and the palladium (3 and 4) derivatives.
gether with the X-ray molecular structure of compound
2. The 31P {1H} NMR spectra of 1 and 2 show the
presence of only one species in each case. They also show
a noticeable decrease in the value of J Pt-P in accordance
with an increase in the oxidation state of the metal
center. Evidence for a Pt-Hg bond comes from the
observation of 199Hg-P coupling (Table 2). These facts
suggest that complexes 1 and 2 are the result of the
oxidative addition of Hg(O2CR)2 (R ) CH3, CF3) to
complex A. Oxidative addition reactions of electrophiles
RX to square-planar d8 organometallic complexes often
Str u ctu r a l Ch a r a cter iza tion of Com p lexes 1 a n d
2. Compounds 1 and 2 have been formulated on the
basis of their elemental analyses and NMR data to-

1110 Organometallics, Vol. 19, No. 6, 2000
Fornie´s et al.
Ta ble 2. 31P {1H} NMR Da ta for Com p lexes 1-4a
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 2
complex
δP (ppm) J Pt-P (Hz) J Hg-P (Hz)
Pt(1)-C(7)
Pt(1)-P(1)
Pt(1)-S(1)
Hg(1)-O(3)
2.081(9)
2.285(3)
2.387(3)
2.137(7)
Pt(1)-O(1)
Pt(1)-Hg(1)
Pt(1)-S(2)
N(1)-C(22)
2.175(6)
2.5535(7)
2.411(3)
1.317(12)
[Pt(C∧P)(S2CNMe2)] (A)
24.70 (s)
35.58 (s)
26.98 (s)
27.77 (s)
21.02 (s)
18.31 (s)
3969.4
[Pd(C∧P)(S2CNMe2)] (B)
1
2
3
4
2744.0
2645.74
398.1
445.20
Hg(1)-Pt(1)-O(1)
Hg(1)-Pt(1)-C(7)
Hg(1)-Pt(1)-S(2) 167.78(7) C(7)-Pt(1)-P(1)
P(1)-Pt(1)-O(1)
S(1)-Pt(1)-C(7)
S(2)-Pt(1)-O(1)
S(2)-Pt(1)-C(7)
94.4(2)
87.3(3)
Hg(1)-Pt(1)-P(1)
Hg(1)-Pt(1)-S(1)
92.34(7)
94.36(7)
82.1(3)
87.7(2)
73.63(9)
99.34(10)
a
C∧P: CH2-C6H4-P(o-tolyl)2. (s): singlet. bCDCl3, 223 K.
98.1(2)
91.9(3)
87.5(2)
90.7(3)
O(1)-Pt(1)-S(1)
S(1)-Pt(1)-S(2)
S(2)-Pt(1)-P(1)
cCD2Cl2, 188 K.
Pt(1)-Hg(1)-O(3) 177.4(2)
CF3COO group [O(3)] and the Pt atom [Pt(1)-Hg(1)-
O(3) ) 177.4(2)°].
The Pt-Hg bond length [2.5535(7) Å] is slightly
shorter than the sum of the radii for Pt and Hg (2.632
Å) calculated from trans-[PtCl3{(E)-NHdC(OMe)Me}2]2
[Pt-Pt ) 2.758(3) Å]10 and Hg2Cl2 [Hg-Hg ) 2.507 Å],11
which have a single unsupported metal-metal bond.
Similar Pt-Hg distances have been reported in other
compounds exhibiting Pt-Hg covalent bonds: [(2-Me2-
NCH2-C6H4)2(µ-MeCO2)PtHg(O2CMe)] [2.513(1) Å];12
[(PPh3)2R-Pt-Hg-R] [2.637(1) Å];13 [PhCH[HgPt-
(PPh3)2Br]COOC10H19] [2.499 Å];14 [N(CH2CH2PPh2)3-
Pt(HgMe)]BPh4 [2.531 (1) Å];15 [PtCl(HgMe)(dmphen)(Z-
MeO2-CCHdCHCO2Me)] [2.558 (1) Å].16 In contrast the
Pt-Hg distance is clearly different from those observed
in mixed Pt-Hg compounds in which the metal interac-
tion has been described as a PtIIfHgII donor bond:
[{2,6-(Me2NCH2)2-C6H3}Pt(µ-{p-tol′′NC(H)N(iPr)}Hg-
BrCl] [2.8331(7) Å],17 trans-[(CH3NH2)2Pt(1,5-diMeC-)2-
Hg](NO3)2‚0.5H2O [2.765(1) Å],18 trans-[(CH3NH2)2Pt(1-
MeC-)2HgCl(NO3)] [2.835(1) Å],18 trans-[(CH3NH2)2Pt(1-
MeC-)2Hg](NO3)2 [2.785(1) Å],18 and [{Pt{CH2-C6H4-
P(o-tolyl)2-κC,P}(S2C-Z)HgX(µ-X)}2] [Z ) NMe2, OEt;
X ) Br, I].6b
It is noteworthy that although complex 2 has been
obtained in a similar way to that described by van Koten
et al., [(2-Me2N-CH2-C6H4)2(µ-MeCO2)PtHg(O2CMe)],12
in our complex the Pt-Hg bond is not supported by an
acetato group. Despite this difference both Pt-Hg
distances are quite similar. Both acetate groups are
coordinated to Pt and Hg in a monodentate fashion. The
Pt-O(1) [2.175(6) Å] distance is slightly longer than
those observed in other platinum derivatives with
monodentate acetate groups, [Pt(O2CCF3)2(dppm)] [2.080-
(4), 2.074(4) Å]19 and [PtCl2(O2CCH3)2(C6H13N)(NH3)]
F igu r e 1. Molecular structure of [Pt(C∧P)(S2CNMe2)(O2-
CCF3)Hg(O2CCF3)] (2).
result in the formation of octahedral complexes. In A,
two bidentate ligands are present, and consequently for
the octahedral products, [Pt{CH2-C6H4-P(o-tolyl)2-
κC,P}(S2CNMe2)(O2CCX3)Hg(O2CCX3)], nine pairs of
enantiomers are possible. The possible structure of one
enantiomer for each pair is given as Supporting Infor-
mation. The stereochemical descriptors recommended
by IUPAC denote each enantiomer. Since the analysis
of all available spectroscopic data does not allow us to
distinguish among all the possible diastereomers, the
molecular structure of 2 has been determined by X-ray
diffraction methods. The stereogeometry of 2 is pre-
sented in Figure 1 together with the atomic labeling
scheme used. Selected bond distances and angles are
shown in Table 3. As can be seen, complex 2 is a
binuclear platinum-mercury derivative in which the
Pt-Hg distance of 2.5535(7) Å is an appropriate value
for a single Pt-Hg bond. Platinum reveals a distorted
octahedral coordination, with the angle between the
perpendicular to the equatorial plane defined by Pt(1),
O(1), S(1), C(7), P(1) and the Hg(1)-S(2) axis being 7.2°.9
Distortion may be mainly due to the small bite angle of
both chelating ligands bonded to platinum [S2CNMe2,
73.63(9)°; C∧P, 82.1(3)°]. Mercury has a linear environ-
ment formed by an oxygen atom of one monodentate
(10) Bandoli, G.; Caputo, P. A.; Intini, F. P.; Sivo, M. F.; Natile, G.
J . Am. Chem. Soc. 1997, 119, 10370.
(11) Dorn, E. J . Chem. Soc., Chem. Commun. 1971, 466.
(12) (a) van der Ploeg, A. F. M. J .; van Koten, G.; Vrieze, K.; Spek,
A. L.; Duisenberg, A. J . M. J . Chem. Soc., Chem. Commun. 1980, 469.
(b) van der Ploeg, A. F. M. J .; van Koten, G.; Vrieze, K.; Spek, A. L.
Inorg. Chem. 1982, 21, 2014.
(13) Rossell, O.; Seco, M.; Torra, I.; Solans, X.; Font-Altaba, M. J .
Organomet. Chem. 1984, 270, C63.
(14) Suleimanov, G. Z.; Bashilov, V. V.; Musaev, A. A.; Sokolov, V.
I.; Reutov, O. A. J . Organomet. Chem. 1980, 202, C61.
(15) Ghilardi, C. A.; Midollini, S.; Moneti, S.; Orlandini, A.; Scapacci,
G.; Dakternieks, D. J . Chem. Soc., Chem. Commun. 1989, 1686.
(16) Cucciolito, E.; Giordano, F.; Panunzi, A.; Rufo, F.; de Felice, V.
J . Chem. Soc., Dalton Trans. 1993, 3421.
(17) van der Ploeg, A. F. M. J .; van Koten, G.; Vrieze, K.; Spek, A.
L.; Duisenberg, A. J . M. Organometallics 1982, 1, 1066.
(18) Krumm, M.; Zangrando, E.; Randaccio, L.; Menzer, S.; Dan-
zmann, A.; Holthenrich, D.; Lippert, B. Inorg. Chem. 1993, 32, 2183.
(19) Tan, A. L.; Low, P. M. N.; Zhou, Z.-Y.; Zheng, W.; Wu, B. M.;
Mak, T. C. W.; Hor, T. S. A. J . Chem. Soc., Dalton Trans. 1996, 2207.
(9) Nardelli, M. Comput. Chem. 1983, 7, 95.

Reactivity of [M(C∧P)(S2CNMe2)]
Organometallics, Vol. 19, No. 6, 2000 1111
[2.06(2) Å],20 probably due to the trans influence of the
σ-bonded carbon atom [C(7)]. The Hg-O(3) bond length
[2.137(7) Å] is similar to that observed in [(2-Me2N-
CH2-C6H4)2(µ-MeCO2)PtHg(O2CMe)] [Hg-O ) 2.10(1)
Å] for the monodentate acetate group.12 Pt-P, Pt-C,
and Pt-S bond distances are similar to those found in
other complexes containing this kind of ligand.6,7 The
S2CNMe2 group is perfectly planar, and the C(22)-N(1)
bond length [1.317(12) Å] indicates a marked degree of
C-N double bond,21 as is usual for dithiocarbamate
ligands.22 In accordance with what is usually observed,
the five-membered metallacycle is not planar but rather
is bent through the P(1)-C(7) vector in such a way that
the angle between the equatorial plane [Pt(1), O(1), S(1),
C(7), P(1)] and the best plane calculated for P(1), C(1),
C(2), C(7) is 24.4°.9
The two unmetalated o-tolyl groups are planar and
are oriented forming angles of 99.3° [C(8)-C(14)] and
11.5° [C(15)-C(21)] with their corresponding Pt-P-
Cipso planes.
F igu r e 2. Molecular structure of [Pd(S2CNMe2){µ-P(o-
tolyl)2-C6H4-CH2-}(µ-O2CCH3)Hg(O2CCH3)] (3).
As for [(2-Me2N-CH2-C6H4)2(µ-MeCO2)PtHg(O2C-
Me)],12 the solid-state structure of 2 shows coordination
geometries for Pt and Hg that are comparable with
those of Pt(IV) and Hg(II) when Pt and Hg are consid-
ered as ligands for each other.
hydrogen atom. Two signals appear separately at about
6.5 and 8.0 ppm, which can be unambiguously assigned
to the ortho-hydrogen [H6] of each inequivalent o-tolyl
group. The values of the P-H6 and H6-H5 coupling
3
constants were calculated in all cases, the J P-H being
The spectroscopic NMR data obtained in solution for
1 and 2 allow us to assign the same structure for them
and confirm that the structure observed for 2 in the solid
state is maintained in solution. The 31P NMR spectra
of 1 and 2 show only a singlet flanked by satellites due
to 195Pt-P and 199Hg-P couplings. The values of the
195Pt-P coupling constants, about 1250 Hz less than in
the starting complex A, are in agreement with a higher
oxidation state of the platinum center.23 These values,
close to 2700 Hz, are similar to those observed in the
Pt(IV) complexes [Pt{CH2-C6H4-P(o-tolyl)2-κC,P}(S2-
CNMe2)X2] (X ) Cl, Br, I).6a The values of the 199Hg-P
coupling constant (1, 398.1 Hz; 2, 445.2 Hz) are as
expected for a Pt-Hg bond cis to the phosphorus atom
in these complexes.24 These spectroscopic features point
out that the oxidative addition of Hg(O2CR)2 (R ) CH3
(1), CF3(2)] to compound A is stereoselective, affording
only the isomer OC-6-23 (Scheme 1) in each case.
similar to those observed in other complexes with
arylphosphine ligands.26 These spectra also show two
singlets at about 3 ppm for the S2CNMe2 ligand, in
agreement with its chelate coordination mode.27 The two
inequivalent CX3COO- groups give two singlets in
the1H or 19F NMR spectra of 1 (X ) H) and 2 (X ) F),
respectively. The correct assignments of the signals due
1
to methyl groups in the H NMR spectrum of 1 could
be carried out with the help of a HETCOR experiment28
and are submitted as Supporting Information.
The 13C NMR spectra of 1 and 2 in CDCl3 at 223 K
display the expected signals for the ligands present in
such complexes and show the inequivalence of the two
carboxylate groups, in agreement with the structure
observed in the solid state for complex 2, but they are
not worthy of further comment (see Experimental
Section)
Str u ctu r a l Ch a r a cter iza tion of Com p lexes 3 a n d
4. The molecular structure of 3 is represented in Figure
2 together with the atomic labeling scheme. Bond
distances and angles are indicated in Table 4.
As can be seen, complex 3 is a Pd/Hg binuclear
derivative in which both metal centers are bridged by
two bidentate ligands (CH3COO-, P(o-tolyl)2-C6H4-
CH2-κC,P). The intermetallic distance is 3.1726(12) Å.
The palladium center is located in a distorted square-
planar environment. The angles between adjacent at-
oms in the coordination sphere of palladium lie in the
range 75.66(7)-99.96(7)°, the smallest angle corre-
sponding to the dimethyldithiocarbamate ligand.
1
The H and 13C NMR data can also be interpreted in
terms of this geometry. The 1H NMR spectra of com-
plexes 1 and 2 in CDCl3 at 223 K display a common
pattern due to the metalacycle “Pt{CH2-C6H4-P(o-
tolyl)2-κC,P}” (see Experimental Section): (a) two sin-
glets at ca. 2 ppm due to the methyl of the inequivalent
o-tolyl groups; (b) a multiplet close to 4 ppm due to the
methylene group which appears as an AB system with
2
a J H-H close to 14 Hz; both hydrogen atoms also appear
coupled to 195Pt (I ) 1/2, 33%), indicating the existence
of a Pt-C bond in the complex;25 (c) several signals
between 6.5 and 8.5 ppm corresponding to the aromatic
(20) Neidle, S.; Snook, C.; Murrer, B. A.; Bernard, C. F. J . Acta
Crystallogr. Sect. C 1995, 51, 822.
(21) Pauling, L. The Nature of the Chemical Bond, 2nd ed.; Cornell
University Press: Ithaca, NY, 1960.
(22) Chan, L. T.; Chen, H.-W.; Fackler, J . P.; Masters, A. F.; Pan,
W.-H. Inorg. Chem. 1982, 21, 4291.
(23) Parish, R. V. NMR, NQR, EPR and Mo´ssbauer Spectroscopy
in Inorganic Chemistry; Ellis Horwood Ltd: New York, 1990.
(24) (a) Tanase, T.; Yamamoto, Y.; Puddephatt, R. J . Organometal-
lics 1996, 15, 1502. (b) van Vliet, P. I.; Kuyper, J .; Vrieze, K. J .
Organomet. Chem. 1976, 122, 99.
(26) (a) Okeya, S.; Miyamoto, T.; Ooi, S.; Nakamura, Y.; Kawaguchi,
S. Bull. Chem. Soc. J pn. 1984, 57, 395. (b) Ooi, S.; Matsushita, T.;
Nishimoto, K.; Nakamura, Y.; Kawaguchi, S.; Okeya, S. Inorg. Chim.
Acta 1983, 76, L55. (c) Widenhoefer, R. A.; Zhong, H. A.; Buchwald, S.
L. Organometallics 1996, 15, 2745.
(27) (a) Fackler, J . P., J r.; Lim, I. J . B.; Andrews, J . Inorg. Chem.
1977, 16, 450. (b) Narayan, S.; J ain, V. K.; Chaudhury, S. J . Orga-
nomet. Chem. 1997, 530, 101.
(28) (a) Croosmur, W. R.; Carlson, R. M. K. Two-Dimensional NMR
Spectroscopy, 2nd ed.; VCH: New York, 1994. (b) Sanders, J . K. M.;
Hunter, B. K. Modern NMR Spectroscopy, 2nd ed.; University Press:
Oxford, 1993.
(25) Kuyper, J . Inorg. Chem. 1978, 17, 1458.

1112 Organometallics, Vol. 19, No. 6, 2000
Fornie´s et al.
The low-temperature 31P{1H} and 1H NMR spectra
of 3 and 4 are very similar, allowing us to assign the
same structure to both complexes (Scheme 1). A HET-
COR28 experiment was performed on complex 3 in order
to correctly assign the H methyl resonances (Support-
ing Information).
Ta ble 4. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3
Pd(1)-S(1)
Pd(1)-P(1)
Hg(1)-C(21)
Hg(1)-O(3)
2.364(2)
2.322(2)
2.103(6)
2.120(5)
Pd(1)-S(2)
Pd(1)-O(2)
Hg(1)-O(1)
N(1)-C(22)
2.307(2)
2.081(4)
2.639(4)
1.314(8)
1
S(1)-Pd(1)-S(2)
O(2)-Pd(1)-P(1)
75.66(6) S(1)-Pd(1)-O(2)
86.78(11) P(1)-Pd(1)-S(2)
97.64(11)
99.96(6)
82.3(2)
In these complexes (3 and 4) the change in the
coordination mode of the P(o-tolyl)2-C6H4-CH2- ligand
using the starting complex, B, causes some differences
O(3)-Hg(1)-C(21) 170.9(2)
O(1)-Hg(1)-C(21) 101.1(2)
O(3)-Hg(1)-O(1)
Hg(1)-C(21)-C(20) 110.0(4)
1
in the corresponding 31P and H NMR signals: (a) the
31P NMR signals of 3 and 4 are shifted to a higher field
in about 15 ppm [14.56 ppm (3), 17.27 ppm (4)]; (b) the
1H signals, due to the methyl (o-tolyl) groups are also
-
The Me2NCS2 ligand is planar and nearly coplanar
with the palladium coordination plane (interplanar
angle 5.16°).9 Bond distances and angles in the ligand
indicate a pronounced degree of C-N double bounding,21
as usual for dithiocarbamate ligands.22
The Pd-S, Pd-P, and Pd-O bond distances are in
the range of distances found in other palladium deriva-
tives containing this type of ligand.5a,6b,29
1
shifted to a higher field in about 1 ppm; and (c) the H
signal corresponding to the H-6 proton of the endo ring
appears at ca. 9.0 ppm. This H-6 proton experiences a
downfield shift due to the paramagnetic anisotropy of
the palladium atom. A similar chemical shift and J PH
values were observed for the H-6 proton of the endo-
1
P(o-tolyl)3 ring in the H NMR spectra of [Pd{P(o-tol)3}-
As in the complex [PdBr(S2COEt){µ-P(o-tolyl)2-C6H4-
CH2-}HgBr],6b the Pd-P length [2.321(2) Å] is longer
than that observed in complexes in which this C∧P
group acts as a chelate ligand: [Pd{CH2-C6H4-P(o-
(hfac)2] (hfac ) 1,1,1,5,5,5,-hexafluoro-2,4-pentane-
dionate)26a,b and [Pd{P(o-tol)3}(p-C6H4Me)(NH(Me)Bn]-
-
Br.26c The Me2NCS2 ligand and the two inequivalent
1
30
carboxylate groups give the expected signals in the H
tolyl)2-κC,P}(µ-I)]2 and [Pd{CH2-C6H4-P(o-tolyl)2-
or 19F NMR spectra (see Experimental Section).
Rea ctivity of [P t{CH2-C6H4-P (o-tolyl)2-κC,P }-
(S2CNMe2)(O2CCF 3)Hg(O2CCF 3)] (2) w ith HBr . The
reaction of [Pt{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)-
(O2CCF3)Hg(O2CCF3)] (2) with a methanol solution of
HBr in chloroform in 1:2 molar ratio at -40 °C give rise
to complex C (Scheme 2a). Complex C had been pre-
pared previously by reaction of complex A with an
equimolar amount of HgBr2 in dichloromethane (Scheme
2b).6b This result seems to indicate that several pro-
cesses take place in this reaction: the displacement of
HO2CCF3 by HBr (Scheme 2c) followed by the reductive
elimination of HgBr2 and formation of complex C in
which the two different metal fragments are joined
through a donor platinum to mercury metal bond
(Scheme 2d).
κC,P}(µ-O2CMe)]2.5a
The Hg atom is bonded to the oxygen of one mono-
dentate acetate group with a Hg-O(3) distance of 2.120-
(5) Å to the oxygen of the bridging acetate group with a
longer Hg-O(1) bond of 2.638(4) Å and to the C(21) of
the bridging P(o-tolyl)2-C6H4-CH2- group with a Hg-
C(21) bond of 2.103(6) Å, showing a T-shaped coordina-
tion environment. The different bond lengths between
Hg-O (terminal acetate) and Hg-O (bridging acetate)
have been previously observed in [(2-Me2N-CH2-
C6H4)2(µ-MeCO2)PtHg(O2CMe)].12 The Hg-C(21) bond
distance is similar to that observed in the analogue
derivative [PdBr(S2COEt){µ-P(o-tolyl)2-C6H4-CH2-}-
HgBr]6b and in other organomercury compounds.3,13-16,31
The bridging acetate group is asymmetrically bonded
[Pd-O(2) ) 2.081(4) Å, Hg-O(1) ) 2.638(4) Å]. The
fragment Hg(1), O(1), C(25), O(2), Pd(1) is not com-
pletely planar, O(1) and O(2) being displaced out of the
best plane by 0.1595 and 0.1136 Å, respectively. The
best plane defined for this fragment is almost perpen-
dicular to the coordination plane of the Pd atom [Pd(1),
S(1), S(2), P(1), O(2)] with an interplanar angle of
97.12°.9
The mercury atom is located close to the perpendicu-
lar of the coordination plane of the palladium center,
the angle between this perpendicular and the Pd-Hg
vector being 9.97°.9 However, despite this small angle,
the long Pd-Hg separation [3.1726(12) Å] suggests that
no bond is formed between both metal centers.18
The two o-tolyl groups of the “P(o-tolyl)2-C6H4-
CH2-” bridging ligand are perfectly planar. In one of
them, [C(8)-C(14)], the o-methyl group is oriented
toward the metal atom (exo), with the o-tolyl ring
rotated 63.91° off the Pd-P-ipso-C plane. In the other
one, [C(1)-C(7], the o-methyl group is directed away
from the metal atom (endo) with the o-tolyl ring rotated
only 4.51° off the Pd-P-ipso-C plane.
Discu ssion
As it has been shown, the reactions of [Pt{CH2-
C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)] (A) with Hg(O2CR)2
(R ) CH3, CF3) afford the stable platinum-mercury
complexes [M{CH2-C6H4-P(o-tolyl)2-κC,P}(S2CNMe2)(O2-
CR)Hg(O2CR)] [R ) CH3 (1), CF3 (2)] as a result of the
cis addition of Hg(O2CR)2 to complex A. These reactions
proceed without Pt-C bond cleavage, although such a
process is promoted by phosphine ligands.32 Other stable
platinum-mercury complexes containing a covalent Pt-
Hg single bond have been prepared by reaction of
square-planar Pt(II) substrates and HgX2 salts as
[PtMe2X(HgX)(N-N)] [N-N ) bpy, X ) O2CCH3, O2-
CCF3; N-N ) Ph2Me2phen, X ) Cl, Br, I, O2CCH3, O2-
CCF3], resulting from cis addition of HgX2 to the
platinum complexes25 and [(2-Me2N-CH2-C6H4)2(µ-
(31) (a) Casas, J . S.; Castellano, E. E.; Garc´ıa-Tasende, M. S.;
Sa´nchez, A.; Sordo, J .; Va´zquez-Lo´pez, E. M.; Zukerman-Schpector, J .
J . Chem. Soc., Dalton Trans. 1996, 1973. (b) Ho¨pp, M.; ErxLeben, A.;
Rombeck, I.; Lippert, B. Inorg. Chem. 1996, 35, 397. (c) Carlson, T. F.;
Fackler, J . P., J r.; Staples, R. J .; Winpenny, R. E. P. Inorg. Chem. 1995,
34, 426.
(29) Orpen, G.; Brammer, L.; Allen, F. H.; Kennard, O.; Watson, D.
G.; Taylor, R. J . Chem. Soc., Dalton Trans. 1989, S1.
(30) Rheingold, A. L.; Fultz, W. C. Organometallics 1984, 3, 1414.
(32) Puddephatt, R. J .; Thompson, P. J . J . Chem. Soc., Dalton Trans.
1977, 1219.

Reactivity of [M(C∧P)(S2CNMe2)]
Organometallics, Vol. 19, No. 6, 2000 1113
Sch em e 2
RCO2)PtHg(O2CR)] or [(2-Me2N-C6H4-CH2)2(µ-RCO2)-
PtHg(O2CR)] (R ) Me, iPr).12 The latter compounds have
been isolated by van Koten et al. and have been
considered as “trapped” intermediates in the concerted
cis addition of a mercury-acetate bond to the Pt(II)
substrate in which the first step involves a Lewis acid-
In other cases, for example in the reaction of cis-[Pd(2-
Me2NCH2-C6H4)2] with Hg(O2CCH3)2,34 which renders
[Pd(2-Me2NCH2-C6H4)(µ-MeCO2)]2 as the final product,
a transmetalation process together with the complete
transference of one C∧N chelating ligand occurs and
proceeds very quickly, so that there is no evidence of
the formation of a palladium-mercury intermediate.
Two mechanisms for the electrophilic cleavage of an σ
M-C bond have been proposed.33 The first one involves
the oxidative addition of the electrophile (HgX2) to the
metal center and the reductive elimination of “RHgX”.
The second one occurs through the electrophilic attack
of the mercury salts on the σ M-C bond. Because of
the low reactivity of our palladium(II) complex, B,
toward oxidative addition reactions, the formation of
complexes 3 and 4 must probably occur through the
electrophilic attack of the Hg(II) salt on the Pd-C bond.
2
base type interaction through the filled dz orbital of a
platinum atom and an empty orbital of a mercury atom.
Since the reaction of A with Hg(O2CCF3)2 in the pres-
-
ence of CH3CO2 renders exclusively compound 2, the
formation of 1 and 2 seems probable to proceed through
a concerted mechanism such as that proposed by van
Koten better than through a polar SN2-type.
The reactions of [Pd{CH2-C6H4-P(o-tolyl)2-κC,P}(S2-
CNMe2)] (B) with Hg(O2CR)2 (R ) CH3, CF3) give rise
to the formation of complexes [Pd(S2CNMe2){µ-P(o-
tolyl)2-C6H4-CH2-}(µ-O2CR) Hg(O2CR))] [R ) CH3 (3),
CF3 (4)] as a result of a transmetalation process. The
same reactivity was observed for complex B when it was
reacted with HgBr2.6b
Con clu sion
Cleavage of the platinum- or palladium-C bond by
electrophiles such as HgX2 (X ) Cl, O2CR) has been
observed previously.33 These reactions result in alkyl
or aryl transfer from the substrate to mercury and the
formation of organomercurials (eq 1).
The reaction of the complexes [Pt{CH2-C6H4-P(o-
tolyl)2-κC,P}(S2CNMe2)] (A) and [Pd{CH2-C6H4-P(o-
tolyl)2-κC,P}(S2CNMe2)] (B) with an equimolar amount
of Hg(O2CR)2 (R ) CH3, CF3) occurs in very different
ways. While A oxidatively adds Hg(O2CR)2 to give the
octahedral compounds OC-6-23 [Pt(C∧P)(S2CNMe2)(O2-
CR)Hg(O2CR)] [R ) CH3 (1), CF3 (2)], which contain a
Pt-Hg covalent bond, the palladium compound B reacts
with Hg(O2CR)2 with cleavage of the σ Pd-C bond. In
these transmetalation processes the C∧P ligand is not
completely transferred, remaining as a bridge between
the two metals centers. The oxidative addition of the
mercury(II) carboxylate to complex A is stereoselective,
and a concerted mechanism seems likely to be operative.
For the transmetalation process the electrophilic attack
“R-M” + HgX2 f “X-M” + RHgX
(1)
It is noteworthy that the internal P-coordination of
the chelating C∧P ligand “CH2-C6H4-P(o-tolyl)2-κC,P”
did not prevent such a reaction, although in these cases
the C∧P ligand is not completely transferred, leading
to the formation of mixed Pd-Hg complexes with said
ligand acting as a bridge between the two metal centers.
(33) (a) J awad, J . K.; Puddephatt, R. J . J . Chem. Soc., Chem.
Commun. 1977, 892. (b) J awad, J . K.; Puddephatt, R. J . Inorg. Chim.
Acta 1978, 31, L391.
(34) van der Ploeg, A. F. M. J .; van Koten, G.; Vrieze, K. J .
Organomet. Chem. 1981, 222, 155.

1114 Organometallics, Vol. 19, No. 6, 2000
Fornie´s et al.
of the Hg(II) salt on the σ Pd-C bond seems plausible.
It would thus seem that the electrophilic attack of the
Hg(II) salt takes place on the metal center when M )
Pt but on the σ Pd-C bond when M ) Pd, in accordance
with the higher nucleophilicity of platinum with respect
to palladium. Similar results were observed previously
in the reactions of A and B with HgBr2, although in
these cases the HgBr2 was not added to complex A, but
a 1:1 adduct [Pt(C∧P)(S2CNMe2)HgBr(µ-Br)]2 was formed
in which the platinum fragment was connected to the
mercury through a weaker platinum to mercury donor-
acceptor bond.
Ack n ow led gm en t. We thank the Direccio´n General
de Ensen˜anza Superior (Spain) for its financial support
(Project PB95-0003-CO2-01) and Prof. R. Navarro for
helpful discussions.
Su p p or tin g In for m a tion Ava ila ble: Tables of crystal
data and structure refinement, atomic coordinates, bond
lengths and angles, anisotropic displacement parameters, and
hydrogen coordinates for complexes 2 and 3. For complexes 1
1
and 3 H-13C HETCOR NMR spectra. For 1 and 2 a drawing
showing the possible diastereoisomers. This material is avail-
able free of charge via the Internet at http://pubs.acs.org.
OM990856G