New C,P-cyclometalated compounds of platinum(II) and platinum(IV) derived from tri-o-tolylphosphine

Article abstract of DOI:10.1021/om950861u

The reaction between [trans-PtCl₂(PhCN)₂] (PhCN = benzonitrile) and tri-o-tolylphosphine rendered [Pt{CH₂C₆H₄P(o-tolyl) ₂-C,P}(μ-Cl)]₂ (1), a new C,P-cyclometalated compound of P

Full text of DOI:10.1021/om950861u

1826
Organometallics 1996, 15, 1826-1833
New C,P -Cyclom eta la ted Com p ou n d s of P la tin u m (II) a n d
P la tin u m (IV) Der ived fr om Tr i-o-tolylp h osp h in e
J . Fornie´s,* A. Mart´ın, R. Navarro, V. Sicilia, and P. Villarroya
Departamento de Qu´ımica Inorga´nica, Instituto de Ciencia de Materiales de Arago´n,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
Received November 3, 1995X
The reaction between [trans-PtCl2(PhCN)2] (PhCN ) benzonitrile) and tri-o-tolylphosphine
rendered [Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 (1), a new C,P-cyclometalated compound of Pt-
(II). The treatment of 1 with AgClO4 (1: 2) in NCMe gave the mononuclear compound [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(NCMe)2]ClO4 (2). Solutions probably containing the cation [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(THF)2]+ (THF ) tetrahydrofuran) reacted with sodium dimethyl-
dithiocarbamate (NaS2CNMe2) and potassium ethyl xanthate (KS2COEt) in 1:1 molar ratio
yielding the mononuclear complexes [Pt{CH2C6H4P(o-tolyl)2-C,P}(S2CR)] (R: NMe2 (3), OEt
(4)). The molecular structure of 3 was determined by X-ray diffraction. The reactions of 3
and 4 with Cl2, Br2 and I2 gave the mononuclear Pt(IV) complexes [Pt{CH2C6H4P(o-tolyl)2-
C,P}(S2CR)X2] (X: Cl, Br, I) (5-10). In each reaction a single product can be detected
spectroscopically, indicating that the oxidative addition of halogens (X2) to 3 and 4 proceeds
stereoselectively. The molecular structure of compound 7, determined by X-ray diffraction,
revealed that the obtained isomer has the OC-6-42 structure with both halogen atoms in cis
positions.
Ch a r t 1
In tr od u ction
Cyclometalation reactions with tertiary phosphines
give organometallic compounds with a C-P-M structure.
Two important factors which promote internal metala-
tion in such complexes are (a) the presence of bulky
substituents on the tertiary phosphine and (b) the
possibility of forming five-membered rings on metala-
tion.1 P(o-tolyl)3 is an adequate ligand for such pro-
cesses since the value of the cone angle, crystallograph-
ically determined, is 198° 2 and the activation of one H
of the CH3 in the o-tolyl substituent leads to a five-
membered ring.
Phosphines with one [PtBu2(o-tolyl)] or two [PtBu(o-
tolyl)2] o-tolyl groups undergo cyclopalladation and
cycloplatination involving the methyl fragment of one
o-tolyl group.3-5 Although tri-o-tolylphosphine under-
goes side chain metalation on Mn6 and Rh7 complexes,
as far as we know, only two palladium derivatives, [Pd-
{CH2C6H4P(o-tolyl)2}(µ-X)]2 (X ) I,8a CH3COO8b), and
one platinum derivative, [Pt{CH2C6H4P(o-tolyl)2}(P(o-
tolyl)3)(Br)],9 with cyclometalated P(o-tolyl)3 have been
reported, [Pd{CH2C6H4P(o-tolyl)2}(µ-I)]2 being the initial
product formed during arylation reactions of conjugated
polyenes using palladium (II) acetate, tri-o-tolylphos-
phine, and triethylamine as catalyst. Recently Her-
rmann et al. have reported that these C,P-cyclometa-
lated Pd(II) complexes are very active catalysts for the
Heck or Suzuki reactions.8b,c
As an extension of our interest in cyclometalated
derivatives,10 we decided to explore the reactions of
cycloplatination of P(o-tolyl)3. In this paper we describe
the synthesis of [Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 (1),
which we have used for the preparation of other Pt(II)
and Pt(IV) complexes containing the “Pt{CH2C6H4P(o-
tolyl)2-C,P}” fragment [Pt(CkP) in the following; see
Chart 1A].
X Abstract published in Advance ACS Abstracts, March 1, 1996.
(1) (a) Omae, I. Organometallic Intramolecular-Coordination Com-
pounds; J . Organomet. Chem. Libr. 18; Elsevier: Oxford, U.K., 1986.
(b) Omae, I. Coord. Chem. Rev. 1980, 32, 235.
(2) Ferguson, G.; Roberts, P. J .; Alyea, E. C.; Khan, M. Inorg. Chem.
1978, 17, 2965.
(3) (a) Cheney, A. J .; Shaw, B. L. J . Chem. Soc., Dalton Trans. 1972,
860. (b) Ibid. 1972, 754.
(4) Gainsford, G. J .; Mason, R. J . Organomet. Chem. 1974, 80, 395.
(5) Cheney, A. J .; McDonald, W. S.; O’Flynn, K.; Shaw, B. L.; Turtle,
B. L. J . Chem. Soc., Chem. Commun. 1973, 128.
(6) McKinney, R. J .; Hoxmeir, R.; Kaesz, H. D. J . Am. Chem. Soc.
1975, 97, 3059.
Resu lts a n d Discu ssion
(A) Syn t h esis a n d Ch a r a ct er iza t ion of [P t -
{CH2C6H4P (o-tolyl)2-C,P }(µ-Cl)]2 (1) a n d [P t{CH2-
(7) (a) Bennett, M. A.; Longstaff, P. A. J . Am. Chem. Soc. 1969, 91,
6266. (b) Mason, R.; Towl, A. D. C. J . Chem. Soc. A 1970, 1601.
(8) (a) Rheingold, A. L.; Fultz, W. C. Organometallics 1984, 3, 1414.
(b) 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. (c) Beller, M.; Fischer, H.; Herrmann, W. A.; O¨ fele, K.;
Brossmer, C. Angew. Chem., Int. Ed. Engl. 1995, 34, 1844.
(9) Chappell, S. D.; Cole-Hamilton, D. J . J . Chem. Soc., Dalton
Trans. 1983, 1051.
(10) Fornie´s, J .; Navarro, R.; Sicilia, V.; Toma´s, M. Inorg. Chem.
1993, 32, 3675 and references given therein.
0276-7333/96/2315-1826$12.00/0 © 1996 American Chemical Society

C,P-Cyclometalated Compounds of Pt(II) and Pt(IV)
Organometallics, Vol. 15, No. 7, 1996 1827
Ta ble 1. 31P {1H} NMRa Da ta for Com p lexes 2-10
singlet at 3.39 ppm with the corresponding 195Pt satel-
lites (2J Pt-H: 101.25 Hz) which confirms the existence
of the Pt-C σ-bond. The equivalence of these two
diasterotopic hydrogen atoms agrees with the existence
of a mirror plane in the molecule. Accordingly, the
methyl groups of the two o-tolylphosphine’s substituents
appear as only one singlet at 2.55 ppm.
(B) Neu t r a l C,P -Cyclom et a la t ed P t (II) Com -
p lexes: [P t(CkP )(S2CR)] (CkP ) -CH2C6H4P (o-
tolyl)2; R ) NMe2 (3), OEt (4)). Solutions of [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(THF)2]ClO4 in methanol or
THF react with sodium dimethyldithiocarbamate (NaS2-
CNMe2) and potassium ethyl xanthate (KS2COEt) in 1:1
molar ratio to give the mononuclear complexes [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(S2CNMe2)] (3) and [Pt{CH2-
C6H4P(o-tolyl)2-C,P}(S2COEt)] (4), in high yields, as air
stable solids (Chart 1D) (eq 3).
complex
δ(P) (ppm)
1J Pt-P (Hz)
[Pt(CkP)(NCMe)2](ClO4)b (2)
[Pt(CkP)(S2CNMe2)]b (3)
[Pt(CkP)(S2COEt)]b (4)
17.19 (s)
24.70 (s)
23.73 (s)
24.20 (s)
21.87 (s)
19.60 (s)
24.91 (s)
23.13 (s)
19.60 (s)
4673.0
3969.4
4083.8
2609.5
2607.9
2620.7
2691.6
2692.5
2620.5
[Pt(CkP)(S2CNMe2)Cl2]b (5)
[Pt(CkP)(S2CNMe2)Br2]b (6)
[Pt(CkP)(S2CNMe2)I2]b (7)
[Pt(CkP)(S2COEt)Cl2]c (8)
[Pt(CkP)(S2COEt)Br2]c (9)
[Pt(CkP)(S2COEt)I2]b (10)
a
CkP = CH2C6H4P(o-tolyl)2-C,P; external reference 85% H3PO4;
CDCl3, room temperature. Recorded on a Varian XL-200. c Re-
b
corded on a Varian Unity 300.
C6H4P (o-tolyl)2-C,P }(NCMe)2]ClO4 (2). Equimolar
quantities of [trans-PtCl2(PhCN)2] and tri-o-tolylphos-
phine react, in refluxing 2-methoxyethanol, giving the
intramolecular coordination complex [Pt{CH2C6H4P(o-
tolyl)2-C,P}(µ-Cl)]2 (1) (Chart 1B) (eq 1).
[Pt{CH2C6H4P(o-tolyl)2-C,P}(THF)2]ClO4 +
MS2CR f [Pt{CH2C6H4P(o-tolyl)2-C,P}(S2CR)] +
MClO4 + 2THF (3)
2[trans-PtCl2(PhCN)2] + 2P(o-tolyl)3 f
[Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 +
2HCl + 4PhCN (1)
M ) Na, R ) NMe2 (3); M ) K, R ) OEt (4)
Complex 1 is insoluble in the usual organic solvents.
Its IR spectrum shows two absorptions due to νst(Pt-
Cl) at 249 and 255 cm-1, consistent with a dinuclear
formulation, [Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 (1). Ab-
sorptions assignable to the CkP ligand (CkP:{CH2C6H4P-
(o-tolyl)2-C,P}) are also observed (see Experimental
Section).
Halide abstraction with AgClO4 (1:2 molar ratio) in
a donor solvent (L), at room temperature, affords the
cationic solvento complexes [Pt{CH2C6H4P(o-tolyl)2-
C,P}(L)2]+ (eq 2) (Chart 1C), which contain two solvent
In spite of the similarity of both complexes, the
isolation procedure is different in each case (see Ex-
perimental Section) due to the solubility of complex 4
in the most common solvents.
In the IR spectrum of 3, the presence of only one
absorption in the 950-1050 cm-1 region (975 cm-1) due
to ν(CS) indicates the bidentate binding of the
“S2CNMe2-” group.13 An absorption at 1543 cm-1
corresponds to the νst(C-N), and suggests a pronounced
degree of C-N double bond.13 In the IR spectrum of 4,
the “S2COEt-” group is characterized by the presence
[Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 + 2AgClO4
2[Pt{CH2C6H4P(o-tolyl)2-C,P}(L)2]+ +
9
L8
of absorptions at 1239, 1123, and 1031 cm-1 13
.
Str u ctu r e of [P t(CH2C6H4P (o-tolyl)2-C,P }(S2CN-
Me2)] (3). Figure 1 shows the molecular structure of 3
with the atom-numbering scheme. General crystal-
lographic information is collected in Table 3. Final
atomic positional parameters are listed in Table 4.
Relevant bond distances and angles are listed in Table
5.
As expected, the platinum atom is located in a
distorted square-planar environment formed by the two
sulfur atoms of the dimethyldithiocarbamate group and
the phosphorus and an alkyl carbon (C(10)) atom of the
C,P-cyclometalated phosphine ligand.
The five-membered metallocycle is not planar. C(4)
and C(10) are 0.176 and 0.252 Å apart from the best
least-squares plane through Pt-P-C(4)-C(9)-C(10).14
The small bite angle of the chelate ligands makes the
corresponding angles smaller than 90°; S(1)-Pt-S(2)
) 74.1(1)° and P-Pt-C(10) ) 84.2(2)°. These param-
eters and the bond distances related with the platinum
environment are similar to those found for other com-
plexes containing these types of chelating groups.3-5,8
2ClO4- + 2AgCl (2)
L ) THF, NCMe
molecules, such as THF (tetrahydrofuran) or NCMe
(acetonitrile) in cis positions. For L ) NCMe, a solid
stable at room temperature, [Pt{CH2C6H4P(o-tolyl)2-
C,P}(NCMe)2]ClO4 (2) was obtained. When L ) THF,
no solid has been isolated, but solutions containing
presumably the [Pt{CH2C6H4P(o-tolyl)2-C,P}(THF)2]+
species have been used as starting materials for the
synthesis of new complexes.
The IR spectrum of 2 (see Experimental Section)
shows the following: (a) two absorptions assignable to
-
the ClO4 (Td) anion,11 (b) several absorptions assign-
able to the CkP ligand, and (c) two absorptions due to
νst(C-N) (2288 (m), 2298 (m) cm-1) of the acetonitrile
groups, denoting their cis positions. The shift to higher
energies of these frequencies with respect to that in the
free ligand (2254 cm-1) suggests that the acetonitrile
groups are N-coordinated, acting as pure σ-donors.12 In
The Pt-S(1) bond length (2.392(2) Å) is slightly longer
than the Pt-S(2) one (2.354(1) Å) because of the
1
the H NMR spectrum (Table 2) the two inequivalent
NCMe ligands give two singlets at 2.22 and 2.55 ppm.
The methylene group of the CkP fragment gives one
(13) Coucouvanis, D. Progress in Inorganic Chemistry; J ohn Wiley
& Sons: New York, 1979; Vol. 26, p 424.
(11) Hathaway, B. J .; Underhill, A. E. J . Chem. Soc. 1961, 3091.
(12) (a) Storhoff, B. N.; Lewis, H. C., J r. Coord. Chem. Rev. 1977,
23, 1. (b) Ford, P. C.; Clarke, R. E. Chem. Commun. 1968, 1109.
(14) Nardelli, M. Comput. Chem. 1983, 7, 95.
(15) Chen, H.-W.; Fackler, J . P., J r.; Masters, A. F.; Pan, W.-H.
Inorg. Chim. Acta 1979, 35, L-333.

1828 Organometallics, Vol. 15, No. 7, 1996
Ta ble 2. 1H NMRa Da ta for Com p lexes 2-10
Fornie´s et al.
Pt-CH2
2J H-H (Hz)
S2COEt
C6H4Me
δ (ppm)
C6H4
δ (ppm)
NCMe
δ (ppm)
S2CNMe2
δ (ppm)
compd
δ (ppm)
2J Pt-H (Hz)
δ (ppm)
3J H-H (Hz)
2
3.39 (s)
101.25
2.55 (s)
6.9-7.3 (m)
6.9-7.3 (m)
6.8-7.6 (m)
7.0-7.6 (m)
7.0-7.6 (m)
7.0-7.6 (m)
7.0-7.6 (m)
7.0-7.6 (m)
7.0-7.6 (m)
2.22 (s)
2.55 (s)
3
4
3.38 (s)
3.44 (s)
3.54 (s)
3.55 (s)
4.28 (d)
4.69 (d)
4.38 (d)
4.82 (d)
4.60 (d)
4.95 (d)
4.23 (d)
4.69 (d)
4.32(d)
4.82 (d)
4.52 (d)
4.95 (d)
85.70
94.30
90.00
98.20
65.40
80.00
68.00
79.00
70.90
73.60
64.40
80.04
66.10
78.81
85.00
72.50
2.42 (s)
2.78 (s)
2.40 (s)
2.74 (s)
2.02 (s)
2.31 (s)
2.00 (s)
2.32 (s)
1.96 (s)
2.33 (s)
2.04 (s)
2.30 (s)
2.02 (s)
2.32 (s)
1.97 (s)
2.35 (s)
3.23 (s)
3.24 (s)
4.64 (q)
1.47 (t)
7.14
5
12.63
12.45
12.64
12.25
12.01
12.25
2.95 (s)
3.20 (s)
2.92 (s)
3.19 (s)
2.90 (s)
3.20 (s)
6
7
8
4.58 (q)
1.45 (t)
4.57 (q)
1.45 (t)
4.54 (q)
1.44 (t)
7.04
6.93
7.17
9
10
aSolvent CDCl3, room temperature, 300 MHz; s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet.
groups are equivalent (3, 2.62 (s) ppm; 4, 2.58 (s) ppm)
and both methylenic protons are equivalent as well (3,
2
2
3.4 (s) ppm, J Pt-H ) 93.6 Hz; 4, 3.54 (s) ppm, J Pt-H
)
94.92 Hz). These data indicate that at room tempera-
ture the molecular plane does not act as a mirror plane,
i.e. the hindered rotation of the P-Cipso bonds. Analysis
of the proton ortho methyl resonances using the ap-
proximation to Eyring’s equation18
∆Gq ) 19.14Tc(9.97 + log Tc/∆ν)
leads to the ∆Gq at the coalescence temperature for the
P-Cipso bond rotation process in complexes 3 and 4 (3,
∆Gq ) 63.53 kJ mol-1, ∆ν ) 108.34 Hz; 4, ∆Gq
)
318
318
63.79 kJ mol-1, ∆ν ) 98.15 Hz). Only a few cases in
which restricted P-Cphenyl bond rotation is also evident
have been reported,9,19 and in most of them this process
is hindered at low temperature but not at room tem-
perature as in our cases.
F igu r e 1. Molecular structure of [Pt(CH2C6H4P(o-tolyl)2-
C,P}(S2CNMe2)] (3).
different trans influence of the P and C donor atoms of
the C,P-cyclometalated group.15
1
The [S2CNMe2-] group is approximately planar.
Bond angles around the N and C(1) atoms average 120°,
as expected considering an sp2 hybridization of both
atoms; however the S(1)-C(1)-S(2) angle is only
112.8(3)° due to the coordination to the platinum center.
The N-C(1) distance (1.336(7) Å) is not far from the
CdN double bond distance (1.265 Å);16 these structural
features are common in chelating dithiocarbamate
complexes.17
The H NMR spectra of 3 and 4 in CDCl3 also show
the signals due to the chelate S-donor ligands (see Table
2). The S2CNMe2- ligand gives two singlets at 3.23 and
3.24 ppm (3) even at 50 °C, indicating a high free energy
of activation (∆Gq) associated with C-N bond rotation
in accord with its pronounced double-bond character in
the dithiocarbamate ligand. This behavior is usual in
dithiocarbamate Pt(II) and Pd(II) complexes.17,20 The
S2COEt- ligand (4) gives its two characteristic signals:
3
NMR Sp ectr a of Com p lexes 3 a n d 4. The 1H NMR
spectra of 3 and 4 in CDCl3 show a similar pattern due
to the cyclometalated group “Pt{CH2C6H4P(o-tolyl)2-
C,P}” (see Table 2). At room temperature (20 °C) the
following is observed: (a) the -CH2- group appears as
an AX system with the corresponding 195Pt satellites,
2J Pt-H being different and the H-H coupling constant
not being observed. (b) The CH3 groups of the o-
tolylphosphine’s substituents appear as two singlets
indicating their inequivalence. Variable-temperature
1H NMR spectra reveal the coalescence of both methyl
groups and both methylenic protons of the “{CH2C6H4P-
(o-tolyl)2-C,P}” ligand at 45 °C. At 50 °C both methyl
4.64 (q), 1.50 (t); J H-H ) 7.14 Hz).
(C) Neu t r a l C,P -Cyclom et a la t ed P t (IV) Com -
p lexes: [P t(CkP )(S2CR)X2] (CkP = -CH2C6H4P (o-
tolyl)2, R ) NMe2, OEt; X ) Cl, Br , I). The reactions
of 3 and 4 with X2 (X ) Cl, Br, I) (1:1 molar ratio) in
dichloromethane at room temperature afford the air-
stable complexes [Pt(CkP)(S2CR)X2] (R ) NMe2, X )
Cl (5), X ) Br (6), X ) I (7); R ) OEt, X ) Cl (8), X )
Br (9), X ) I (10)) in high yields.
Oxidative addition reactions of halogens to square-
planar d8 organometallic complexes often result in the
(18) Gu¨nther, H. NMR Spectroscopy: An Introduction; J ohn Wiley
and Sons: Chichester, U.K., 1980.
(19) Howell, J . A. S.; Palin, M. G.; McArdle, P.; Cunningham, D.;
Goldschmidt, Z.; Gottlieb, H. E.; Hezroni-Langerman, D. Organome-
tallics 1993, 12, 1694.
(20) Fackler, J . P., J r.; Lin, I. J . B.; Andrews, J . Inorg. Chem. 1977,
16, 450.
(16) Pauling, L. The Nature Of The Chemical Bond, 2nd ed.; Cornell
University Press: Ithaca, NY, 1960.
(17) Chan, L. T.; Chen, H.-W.; Fackler, J . P., J r.; Masters, A. F.;
Pan, W.-H. Inorg. Chem. 1982, 21, 4291.

C,P-Cyclometalated Compounds of Pt(II) and Pt(IV)
Organometallics, Vol. 15, No. 7, 1996 1829
Ta ble 3. Su m m a r y of Cr ysta llogr a p h ic Da ta
3
7
formula
Mr
C24H26NPPtS2‚CHCl3
738.043
C24H26I2NPPtS2‚1/2CH2Cl2
914.941
cryst system
monoclinic
monoclinic
space group
P21/c
P21/c
systematic absences
0k0, k ) 2n + 1; h0l, l ) 2n + 1
0k0, k ) 2n + 1; h0l, l ) 2n + 1
a, Å
b, Å
c, Å
â, deg
V, Å3
Z
12.2980(10)
10.961(2)
12.9748(10)
18.2293(18)
105.766(10)
2799.3(4)
4
1.75
14.431(3)
18.587(4)
91.39(3)
2939(1)
4
2.07
d
calc, g cm-3
cryst size, mm
0.45 × 0.26 × 0.19
0.38 × 0.38 × 0.45
µ(Mo KR), cm-1
55.2
71.8
transm factors (min, max)
diffractometer
0.675, 0.965
Siemens/Stoe AED2
0.485, 1.000
Nicolet (Siemens) Autodiff
radiation (graphite monochromated)
T, °C
scan method
Mo KR (λR ) 0.710 73 Å)
Mo KR (λR ) 0.710 73 Å)
20 ( 1
ω
20 ( 1
ω
scan range, deg
4 < 2θ < 50
4858
3996
ψ scans
326
0.029
0.044
0.95
0.0015
0.001
3 < 2θ < 51
5396
3494
ψ scans
293
0.038
0.049
0.96
0.0013
0.001
no. of unique data
no. of unique data with Fo g 3σ(Fo
abs corr
2
2
)
no. of refined params
Rb
Rw
c
quality of fit indicatord
weighting param ge
largest shift/esd final cycle
final diff Fourier max peak, trough, e/Å3
0.83, -0.96
1.39, -1.06
a
b
3, [Pt{CH2C6H4P(o-tolyl)2-C,P}(S2CNMe2)]‚CHCl3; 7, [Pt{CH2C6H4P(o-tolyl)2-C,P}(S2CNMe2)I2]‚1/2CH2Cl2. R ) ∑||Fo| - |Fc||/∑|Fo|.
c Rw ) [∑w (|Fo| - |Fc|)2/∑w|Fo| ]1/2
.
Quality of fit ) [∑w(|Fo| - |Fc|)2/(Nobservns - Nparameters)]1/2
.
e w-1 ) [σ2 (|Fo|) + g|Fo |].
2
d
2
formation of octahedral complexes.21 Assuming that the
CkP and S2CR- groups maintain their chelating func-
tion, these octahedral Pt(IV) complexes can exhibit three
different structures (Chart 2). The dichloro complexes
[Pt(CkP)(S2CR)Cl2] (R: NMe2 (5), OEt (8)) show two
absorptions at about 310 and 270 cm-1 (see Experimen-
tal Section) assignable to the ν(Pt-Cl) stretching vibra-
tions, but this feature does not allow us to distinguish
between any of the three possible isomers because two
IR-active absorptions should be expected for each one
of them (Chart 2).
In the IR spectra of complexes 5-7 the νst(C-N)
absorptions appear at higher frequencies than in their
precursor (complex 3), showing a correlation between
increasing oxidation state and the C-N stretching
frequency as has been observed previously.22
methyl groups; (b) two signals for the diasterotopic H
atoms of the methylene group, which appear as an AB
system with the corresponding 195Pt satellites, and (c)
some multiplets corresponding to the aromatic hydro-
gens. The inequivalence of both methyl groups and both
H atoms of -CH2- can be explained in two different
ways: (a) complexes 5-10 show either an OC-6-42 or
OC-6-32 geometry, which excludes the existence of any
symmetry plane, or (b) these complexes show the
geometry OC-6-14 but a hindered P-Cipso bond rotation
process precludes the equatorial plane of the molecule
to act as a mirror plane. In the last case, temperature-
dependent 1H NMR spectra should be expected as for
complexes 3 and 4. However we have observed that the
1H NMR spectrum of complex [Pt(CkP)(S2CNMe2)I2] (7)
remain invariable even at 60 °C, suggesting the struc-
ture OC-6-42 or OC-6-32 as more probable. The X-ray
study on complex [Pt(CkP)(S2CNMe2)I2] (7) indicates an
OC-6-42 geometry for it. The similarity of the IR and
NMR spectra of these Pt(IV) complexes suggests the
same geometry for all of them; i.e., the oxidative
addition takes place in a stereoselective mode in all
cases.
The most common mechanism in oxidative addition
reactions of halogens (X2) on square-planar platinum-
(II) complexes is the SN2 type,24 the process being
initiated by end-on coordination of X2 formed by dona-
tion of electron density from the metal to the X2
molecule (A, Scheme 1). The basicity of the platinum
center in [Pt(CkP)(S2CR)] (3, 4) becomes apparent
considering their ability to form donor-acceptor PtfM
bonds.25 The subsequent steps very often result in a
trans addition of the halogen (Scheme 1, path 2) yielding
The 31P{1H} NMR spectra of complexes 5-10 (see
Table 1) show one singlet at about 20.0 ppm with the
corresponding 195Pt satellites, which indicates that only
one diastereomer is present in each case. The smaller
Pt-P coupling constant in these complexes (1J Pt-P
)
2600-2700 Hz) with respect to that in their Pt(II)
precursors (3 and 4) is consistent with a higher oxida-
tion state of the metal center.23
The 1H NMR signals corresponding to the CkP
fragment show, for all complexes, the same pattern (see
Table 2): (a) two signals at ca. 2.0 ppm due to the
(21) (a) Fornie´s, J .; Fortun˜o, C.; Go´mez, M. A.; Menjo´n, B. Organo-
metallics 1993, 12, 4368. (b) van Beek, J . A. M.; van Koten, G.;
Wehman-Ooyevaar, I. C. M.; Smeets, W. J . J .; van der Sluis, P.; Spek,
A. L. J . Chem. Soc., Dalton Trans. 1991, 883.
(22) Edgar, B. L.; Duffy, D. J .; Palazzotto, M. C.; Pignolet, L. H. J .
Am. Chem. Soc. 1973, 95, 1125.
(23) (a) Parish, R. V. NMR, NQR, EPR and Mo¨ssbauer Spectroscopy
in Inorganic Chemistry; Ellis Horwood Ltd: New York, 1990. (b)
Pregosin, P. S. 31P and 13C NMR of Transition Metal Phosphine
Complexes; Springer-Verlag: Berlin, 1979.
(24) Skinner, C. E.; J ones, M. M. J . Am. Chem. Soc. 1969, 91, 4405.
(25) Sicilia, V. Unpublished results.

1830 Organometallics, Vol. 15, No. 7, 1996
Fornie´s et al.
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 Coefficien ts
(Å2 × 103) for [P t{CH2C6H4P (o-tolyl)2-C,P }-
(S2CNMe2)]‚CHCl3
Sch em e 1
x
y
z
U(eq)a
Pt
P
S(1)
S(2)
2446(1)
3531(1)
1669(1)
1318(1)
556(4)
1100(4)
434(6)
36(7)
3060(1)
2037(1)
4361(1)
4104(1)
5772(4)
4871(4)
6419(6)
6132(6)
1356(4)
794(4)
3161(1)
4040(1)
3800(1)
2194(1)
2779(3)
2909(3)
3407(5)
1998(4)
3522(3)
3862(3)
3411(3)
2630(4)
2299(3)
2746(3)
2404(3)
4385(3)
4148(3)
4369(4)
4831(4)
5063(3)
4843(3)
5106(4)
4893(3)
5580(3)
6222(4)
6185(5)
5511(5)
4855(4)
4131(4)
6304(2)
7251(4)
6156(9)
5782(9)
6470(7)
7179(5)
5551(10)
43(1)
40(1)
61(1)
62(1)
66(2)
54(2)
86(3)
88(3)
44(2)
53(2)
60(2)
68(3)
62(2)
48(2)
62(2)
41(2)
52(2)
69(3)
78(3)
67(2)
51(2)
71(3)
46(2)
54(2)
72(3)
80(3)
80(3)
60(2)
84(3)
158(7)
120(4)
255(11)
153(6)
161(5)
181(6)
223(11)
N
C(1)
C(2)
C(3)
C(4)
C(5)
C(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)
C(25)
Cl(1)
Cl(2)
Cl(3)
Cl(4)
Cl(5)
Cl(6)
4384(4)
5344(5)
5919(5)
5531(6)
4585(5)
3999(4)
2997(6)
2745(4)
2814(5)
2220(5)
1517(6)
1432(5)
2029(4)
1870(6)
4566(4)
4732(5)
5561(6)
6264(6)
6121(5)
5278(5)
5190(6)
1334(5)
1665(10)
2227(11)
1643(20)
2335(11)
2026(11)
1424(23)
309(5)
394(5)
961(5)
1469(4)
2154(5)
1036(4)
12(4)
-763(5)
-547(6)
449(6)
1272(5)
2326(6)
2487(4)
1962(4)
2250(6)
3057(6)
3594(6)
3331(4)
3916(5)
6370(4)
5913(10)
7367(7)
5315(13)
7382(9)
5780(14)
5546(17)
We tried to find some experimental evidence about
the possible reaction mechanism by focusing our study
on the iodination reaction of [Pt(CkP)(S2CNMe2)] (3).
Assuming that the oxidative addition of halogen to [Pt-
(CkP)(S2CNMe2)] (3) takes place in a concerted fashion,
iodination of 3 in the presence of chloride anions should
exclusively give products derived from the already
formed complex [Pt(CkP)(S2CNMe2)I2] (7) by simple
halide substitution (C or C′). In the reaction of [Pt-
(CkP)(S2CNMe2)I2] (7) with NEt3BzCl in a 1:1 molar
ratio ([2H]chloroform, room temperature) we observe the
appearance of a single new product (C or C′; 31P{1H}
a
Equivalent isotropic U defined as one-third of the trace of the
orthogonalized Uij tensor.
Ta ble 5. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [P t{CH2C6H4P (o-tolyl)2-C,P }(S2CNMe2)] (3)
Pt-C(10)
Pt-P
Pt-S(1)
Pt-S(2)
2.063(7)
2.223(1)
2.392(2)
2.354(1)
C(1)-S(1)
C(1)-S(2)
C(1)-N
1.717(6)
1.718(6)
1.336(7)
S(1)-Pt-S(2)
S(1)-Pt-P
P-Pt-C(10)
S(2)-Pt-C(10)
S(1)-C(1)-S(2)
74.1(1)
S(2)-C(1)-N
S(1)-C(1)-N
C(1)-N-C(2)
C(1)-N-C(3)
C(2)-N-C(3)
123.1(5)
124.1(5)
121.2(5)
121.0(6)
117.8(5)
1
NMR: δ 20.69, J Pt-P ) 2634.4 Hz) which means that
108.2(1)
84.2(2)
93.5(2)
112.8(3)
halide substitution on 7 proceeds specifically at a certain
position. This substitution reaction depends on the
temperature and does not take place at -60 °C even in
a 1:3 molar ratio. Because of that, we performed the
iodination of 3 in the presence of NEt3BzCl (1:3) at -78
°C in CD2Cl2. The 31P{1H} NMR spectrum of the
reaction mixture at this temperature shows signals
corresponding to 7 and C (or C′) in the integrated ratios
0.926:1. The presence of C (or C′) as a reaction product
allows us to accept the SN2 mechanism including an
additional isomerization step to explain the cis arrange-
ment of the halogen atoms in the final product.
Ch a r t 2
Aiming to know which intermediate species (OC-6-
14 isomer or B+) undergoes further isomerization, we
performed the reaction of [Pt(CkP)(S2CNMe2)] (3) with
I2 at -78 °C in CD2Cl2 in a NMR tube monitoring the
progress of the reaction at -78, -65, -50, -35, -20, 0,
and 20 °C by 31P{1H} NMR. At -78°C, the reaction
mixture show the presence of two different products, the
final one (7) and an intermediate (X) (31P{1H}: δ 16.04,
1J Pt-P ) 2376 Hz. 1H: δ Pt-CH2, 3.18 (d), 5.43 (d),
the isomer OC-6-14. In our case, however, the couple
of enantiomers OC-6-42 were solely obtained in all
cases. These results mean that either the halogen
molecule adds at once in a concerted fashion at cis
positions or that isomerization must follow some of the
proposed steps for the SN2 mechanism.

C,P-Cyclometalated Compounds of Pt(II) and Pt(IV)
Organometallics, Vol. 15, No. 7, 1996 1831
Ta ble 6. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t Coefficien ts
(Å2 × 103) for [P t{CH2C6H4P (o-tolyl)2-C,P }-
(S2CNMe2)I2]‚1/2CH2Cl2
x
y
z
U(eq)a
Pt
I(1)
I(2)
P
S(1)
S(2)
N
2572(1)
197(1)
2670(1)
3714(3)
2359(3)
1196(1)
1623(1)
2632(1)
1924(2)
-240(2)
149(2)
-1470(6)
2973(7)
1086(7)
2856(9)
657(9)
1694(8)
2155(8)
-643(7)
4215(9)
3316(8)
854(8)
1372(1)
1715(1)
472(1)
2276(1)
1954(1)
493(1)
1109(5)
2735(5)
2974(6)
1971(7)
2945(7)
795(6)
1804(5)
1178(6)
2754(7)
3377(6)
3515(6)
1026(7)
468(7)
1215(6)
3766(7)
2431(6)
3382(8)
979(7)
3560(7)
1547(8)
1728(7)
3694(7)
4046(7)
3478(8)
4028(8)
-721(13)
108(12)
-709(17)
29(1)
47(1)
45(1)
30(1)
40(1)
40(1)
39(3)
31(3)
39(4)
46(4)
53(5)
40(4)
37(4)
37(4)
49(4)
38(4)
43(4)
47(4)
59(5)
38(4)
53(5)
36(3)
57(5)
56(5)
58(5)
54(5)
69(6)
49(4)
63(5)
69(6)
79(7)
214(9)
190(7)
142(18)
1716(3)
1153(9)
C(11)
C(18)
C(9)
C(23)
C(6)
C(4)
C(1)
C(15)
C(12)
C(19)
C(10)
C(2)
C(5)
C(17)
C(16)
C(14)
C(7)
C(24)
C(8)
C(3)
C(13)
C(20)
C(22)
C(21)
Cl(1)
Cl(2)
C(50)
3255(10)
4106(11)
5920(11)
5265(13)
6270(10)
5084(10)
1656(10)
1755(12)
3791(11)
3276(12)
4306(11)
458(14)
5254(10)
4890(12)
2239(10)
2255(13)
7113(12)
2040(12)
6939(12)
1143(15)
3266(12)
3661(16)
5595(15)
4816(19)
-1099(20)
809(18)
F igu r e 2. Molecular structure of [Pt(CH2C6H4P(o-tolyl)2-
C,P}(S2CNMe2)I2] (7).
2
2J H-H ) 12.5 Hz, J Pt-H )75 Hz; o-tolyl, 1.78 (s), 1.85
831(9)
(s); S2CNMe2, 3.25 (s), 3.28 (s)). As temperature in-
creases, the amount of 7 grows meanwhile the amount
of (X) decreases with 7 being the only product in the
reaction mixture at room temperature (20 °C). The
possible conversion of X to 7 at low temperatures (T <
-60 °C) even in the presence of NEt3BzCl and the very
different δ values observed for the signals corresponding
to both H atoms of the Pt-CH2 group in this species
(X) suggest that this intermediate (X) can be either A,
B+, or B′+ (Scheme 1) rather than the Pt(IV) isomer OC-
6-14 whose isomerization probably would need higher
temperatures26 and in which both H atoms of the Pt-
CH2- group would have very similar chemical environ-
ments. However, we cannot determine the exact nature
of the intermediate (X). From this observation we
suggest that, in all likelihood, isomerization occur at the
Pt(IV) cation (B+, Scheme 1, path 1) rather than at the
coordinatively saturated product OC-6-14.
-1755(9)
1567(8)
2878(9)
3443(7)
4527(9)
2386(10)
1255(10)
2969(10)
-2109(9)
4082(8)
235(9)
19(10)
-173(11)
4673(16)
5576(14)
5579(26)
-27(35)
a
See footnote a in Table 4.
Ta ble 7. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for [P t{CH2C6H4P (o-tolyl)2-C,P }(S2CNMe2)I2]
(7)
In conclusion from our study on oxidation reactions
of [Pt(CkP)(S2CNMe2)] and [Pt(CkP)(S2COEt)] with
chlorine, bromine, and iodine we can say that these
reactions do not proceed in a concerted fashion but by
an SN2 mechanism including an isomerization step
probably at the five-coordinated Pt(IV) cation interme-
diate to give a unique final product in each case with a
cis arrangement of the halide ligands.
Pt-I(1)
Pt-I(2)
Pt-C(10)
2.764(1)
2.668(1)
2.089(12)
Pt-P
2.323(3)
2.353(3)
2.400(3)
Pt-S(1)
Pt-S(2)
I(1)-Pt-I(2)
I(1)-Pt-P
I(1)-Pt-S(1)
I(1)-Pt-S(2)
I(1)-Pt-C(10)
91.4(1)
103.1(1)
89.2(1)
86.7(1)
174.9(3)
S(1)-Pt-S(2)
P-Pt-S(1)
I(2)-Pt-P
I(2)-Pt-S(2)
P-Pt-C(10)
73.6(1)
97.1(1)
94.2(1)
94.7(1)
81.9(3)
Molecu la r Str u ctu r e of [P t{CH2C6H4P (o-tolyl)2-
C,P }(S2CNMe2)I2] (7). The stereogeometry of this
platinum complex, as determined by single-crystal
experiments, is illustrated in Figure 2 together with the
atomic numbering scheme. General crystallographic
information is collected in Table 3. Final atomic posi-
tional parameters are listed in Table 6. Relevant bond
distances and angles are listed in Table 7.
The molecule shows a slightly distorted octahedral
geometry around the platinum atom. One iodine atom
[I(1)] and the carbon of the CkP group are in the axial
sites, and the I(2), the bidentate dimethyldithiocarbam-
ate ligand, and the P of the CkP group are located in
the equatorial positions, with the angle between the line
1 (I(1), Pt, C(10)) and the perpendicular to the equatorial
plane defined by the atoms I(2), S(1), S(2), Pt, and P
being 7.50°.14 Both P and S(2) atoms are located outside
plane 1 at 0.1368 and 0.1740 Å, respectively.
Angles around the platinum are rather different from
90° because of the small bite angles of the chelate
ligands. The Pt-I distances are similar to the observed
ones in other Pt(IV) iodo complexes27 and slightly
different from each other, showing the stronger trans
influence of the C(sp3) σ-bond.15 The Pt-C, Pt-P, and
Pt-S distances are similar to the corresponding ones
in the starting material (complex 3). The metallacycle
formed by the atoms Pt, C(10), C(5), C(4), and P is not
planar, the atoms C(4) and C(10) being above and below
the best least-squares-calculated plane 0.3826 and
0.5218 Å, respectively. The two o-tolyl groups are
planar, and they are oriented by forming an angle of
112.43° between them and 57.115 and 84.80°, respec-
tively, with the equatorial plane.
(26) Wehman-Ooyevaar, I. C. M.; Drenth, W.; Grove, D. M.; van
Koten, G. Inorg. Chem. 1993, 32, 3347.
(27) (a) Cheetman, A. K.; Puddephatt, R. J .; Zalkin, A.; Templeton,
D. H.; Templeton, L. K. Inorg. Chem. 1976, 15, 2997. (b) Casalone, G.;
Mason, R. Inorg. Chim. Acta 1973, 7, 429.
The S2CNMe2 ligand is basically planar and almost
coplanar with the equatorial plane (interplanar angle
5.77°). Like in complex 3, the structural parameters

1832 Organometallics, Vol. 15, No. 7, 1996
Fornie´s et al.
4.07. Found: C, 46.66; H, 4.08. IR (cm-1): CkP, 458 (m), 477
(s), 487 (m), 505 (m), 586 (s), 758 (vs), 1567 (w), 1586 (w);
-S2COEt, 1031 (vs), 1123 (vs), 1239 (vs).
-
concerning the Me2NCS2 ligand point out to a high
degree of C-N double-bond character.
[P t{CH2C6H4P (o-tolyl)2-C,P }(S2CNMe2)X2] (X ) Cl (5),
Br (6), I (7). X ) Cl. To a pale yellow solution of [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(S2CNMe2)] (3) (0.6 g, 0.9698 × 10-3
mol) in CH2Cl2 (20 mL) was added a slight excess of Cl2 in
CCl4 (1.1 × 10-3 mol), and immediately the solution turned
yellow. After 10 min of stirring at room temperature the
solution was evaporated to dryness and OEt2 (20 mL) was
added to the residue to give a yellow solid, which was filtered
off, dried, and identified as 5 (yield 0.515 g, 77%). Anal. Calcd
for C24Cl2H26NPPtS2: C, 41.80; H, 3.80; N, 2.03. Found: C,
41.87; H, 3.87; N, 1.98. IR (cm-1): CkP group, 455 (s), 475
(s), 487 (s), 506 (m), 522 (s), 536 (s), 551 (s), 567 (m), 583 (m),
751 (vs), 759 (s), 767 (m), 1588 (w); -S2CNMe2, 1561 (vs) (ν-
(C-N)), 978 (w) (ν(C-S)); Pt-Cl, 272 (m), 311 (m).
Exp er im en ta l Section
Gen er a l P r oced u r es a n d Ma ter ia ls. Elemental analyses
were determined by using a Perkin-Elmer 240-B microana-
lyzer. IR spectra were recorded on a Perkin-Elmer 599
spectrophotometer (Nujol mulls between polyethylene 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. [trans-PtCl2-
(PhCN)2] was prepared by the literature method.28
Sa fet y Not e. Perchlorate salts are potentially explosive.
Only small amounts of material should be prepared, and these
should be handled with great caution!
[P t{CH2C6H4P (o-tolyl)2-C,P }(µ-Cl)]2 (1). A mixture of
[trans-PtCl2(PhCN)2] (2.0 g, 4.235 × 10-3 mol) and tri-o-
tolylphosphine (1.29 g, 4.235 × 10-3 mol) in 2-methoxyethanol
(25 mL) was refluxed for 30 min. The initial suspension
dissolved to give a clear pale yellow solution, and then a white
crystalline solid was deposited. After cooling, the solid was
filtered off, washed with methanol and diethyl ether, and
identified as complex 1 (yield 1.9 g, 84%). Anal. Calcd for
Com p lexes 6 (X ) Br ) and 7 (X ) I) were prepared
similarly.
Com p lex 6 (X ) Br ). 3 (0.2877 g, 0.465 × 10-3 mol) and
Br2 in CCl4 (0.558 × 10-3 mol) were used. Yield: 0.323 g, 89%.
Anal. Calcd for Br2C24H26NPPtS2: C, 37.03; H, 3.37; N, 1.80.
Found: C, 37.36; H, 3.27; N, 1.71. IR (cm-1): CkP group, 455
(s), 475 (s), 487 (s), 507 (m), 523 (s), 536 (s), 551 (s), 567 (m),
583 (m), 751 (vs), 757 (s), 765 (m), 1636 (w); -S2CNMe2, 1558
(vs) (ν(C-N)), 977 (w) (ν(C-S)).
C
42Cl2H40P2Pt2: C, 47.26; H, 3.78. Found: C, 47.54; H, 3.86.
IR (cm-1): CkP, 467 (vs), 479 (vs), 486 (vs), 527 (vs, sh), 564
(vs), 585 (vs), 750 (vs), 759 (vs), 784 (m), 806 (m), 1568 (m),
1584 (m), 1590 (m); ν(Pt-Cl), 249 (s), 255 (s).
Com p lex 7 (X ) I). 3 (0.3036 g, 0.4907 × 10-3 mol) and I2
(0.137 g, 0.54 × 10-3 mol) were used. Yield: 0.385 g, 90%.
Anal. Calcd for C24H26I2NPPtS2: C, 33.04; H, 3.00; N, 1.60.
Found: C, 32.93; H, 3.38; N, 1.46. IR (cm-1): CkP group, 454
(m), 472 (m), 487 (w), 505 (w), 519 (m), 536 (m), 550 (w), 567
(w), 580 (w), 748 (vs), 762 (s), 1584 (w); -S2CNMe2, 1549 (vs)
(ν(C-N)), 976 (w) (ν(C-S)).
[P t{CH2C6H4P (o-tolyl)2-C,P }(S2COEt)X2] (X ) Cl (8), Br
(9), I (10)). X ) Cl. To a pale yellow solution of [Pt-
{CH2C6H4P(o-tolyl)2-C,P}(S2COEt)] (4) (0.2497 g, 0.403 × 10-3
mol) in CH2Cl2 (25 mL) was added a little excess of Cl2 in CCl4
(0.462 × 10-3 mol). The mixture was stirred at room temper-
ature for 5 min, and then the solution was evaporated to
dryness. Addition of OEt2 (20 mL) to the residue afforded a
solid, which was identified as 8 (yield 0.223 g, 80%). Anal.
Calcd for C24Cl2H25OPPtS2: C, 41.74; H, 3.65. Found: C,
41.71; H, 3.66. IR (cm-1): CkP group, 453 (s), 475 (s), 488 (s),
503 (w), 522 (s), 535 (s), 552 (m), 567 (w), 583 (m), 749 (s), 761
(vs),1567 (w), 1591 (m); -S2COEt, 1030 (s), 1298 (vs); Pt-Cl,
276 (m), 306 (m).
[P t{CH2C6H4P (o-tolyl)2-C,P }(NCMe)2]ClO4 (2). To a sus-
pension of [Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 (1) (0.6407 g,
0.6 × 10-3 mol) in acetonitrile (20 mL) was added AgClO4
(0.2488 g, 1.2 × 10-3 mol), and the mixture was stirred for 4
h at room temperature. The AgCl precipitated was filtered
off and washed with 5 mL of acetonitrile. Evaporation of the
resulting solution to dryness followed by addition of OEt2 to
the residue afforded a white solid which was identified as 2
(yield 0.71 g, 87%). Anal. Calcd for C25ClH26N2O4PPt: C,
44.16; H, 3.85; N, 4.12. Found: C, 43.79; H, 3.66; N, 3.95. IR
(cm-1): CkP, 466 (s), 479 (s), 487 (s), 516 (m), 531 (s), 566 (s),
589 (s), 759 (s), 772 (s), 793 (s), 1568 (w), 1589 (w); NCMe,
2288 (m), 2298 (m), 2324 (m); ClO4-, 1083 (vs, br), 623 (s).
[P t{CH2C6H4P (o-tolyl)2-C,P }(S2CNMe2)] (3). To a stirred
suspension of [Pt{CH2C6H4P(o-tolyl)2-C,P}(µ-Cl)]2 (1) (0.8544
g, 0.8 × 10-3 mol) in THF (40 mL) was added AgClO4 (0.3317
g, 1.6 × 10-3 mol), and the mixture was stirred at room
temperature for 4 h. The AgCl precipitated was filtered off,
and the resulting solution was evaporated almost to dryness.
The residue was treated with 30 mL of methanol, and the
addition of NaS2CNMe2‚2H2O (0.2867 g, 1.6 × 10-3 mol) to
the solution gave rise to a white solid, which was filtered off,
recrystallized from CH2Cl2/n-hexane, and identified as 3 (yield
0.88 g, 89%). Anal. Calcd for C24H26NPPtS2: C, 46.59; H, 4.24;
N, 2.26. Found: C, 46.71; H, 3.89; N, 2.24. IR (cm-1): CkP,
465 (s), 476 (s), 486 (s), 514 (m), 529 (m), 562 (s), 583 (s), 754
(vs), 765 (vs), 1583 (w); -S2CNMe2, 1543 (vs) (ν(C-N)); 975
(vs) (ν(C-S)).
Syn th esis of [P t{CH2C6H4P (o-tolyl)2-C,P }(S2COEt)] (4).
To the resulting solution of the treatment of [Pt{CH2C6H4P-
(o-tolyl)2-C,P}(µ-Cl)]2 (1) (0.5447 g, 0.51 × 10-3 mol) with
AgClO4 (0.2116 g, 1.02 × 10-3 mol) in THF (20 mL), after
elimination of the AgCl, was added KS2COEt (0.1636 g, 1.02
× 10-3 mol) and the mixture stirred for 15 min at room
temperature. Then, the solution was evaporated to dryness
and n-pentane (100 mL) was added to the residue. After
filtration, the resulting solution was concentrated to 10 mL
and cooled to ca. 5 °C. The yellow solid precipitated was
filtered off, heated at 70 °C for 24 h, and identified as 4 (yield
0.474 g, 75%). Anal. Calcd for C24H25OPPtS2: C, 46.52; H,
Com p lexes 9 (X ) Br ) a n d 10 (X ) I) were prepared
similarly.
Com p lex 9 (X ) Br ). 4 (0.2010 g, 0.32 × 10-3 mol) and
Br2 in CCl4 (0.372 × 10-3 mol) were used. Yield: 0.2 g, 80%.
Anal. Calcd for Br2C24H25OPPtS2: C, 36.98; H, 3.23. Found:
C, 36.73; H, 3.50. IR (cm-1): CkP group, 453 (m), 474 (m),
487 (m), 502 (w), 521 (m), 535 (m), 552 (w), 567 (w), 582 (w),
758 (m, sh), 1565 (w), 1591 (m); -S2COEt, 1032 (s), 1291 (vs).
Com p lex 10 (X ) I). 4 (0.1554 g, 0.25 × 10-3 mol) and I2
(73 mg, 0.287 × 10-3 mol) were used. Yield: 0.157 g, 72%.
Anal. Calcd for C24H25I2OPPtS2: C, 33.00; H, 2.88. Found:
C, 32.62; H, 2.96. IR (cm-1): CkP group, 454 (m), 474 (m),
486 (m), 503 (m), 521 (m), 536 (m), 551 (m), 567 (m), 580 (m),
744 (m), 1567 (w), 1591 (w); -S2COEt, 1032 (s), 1288 (vs).
Cr yst a llogr a p h ic St u d ies. [P t {CH 2C6H 4P (o-t olyl)2-
C,P }(S2CNMe2)]‚CHCl3 (3). Important crystal data and data
collection parameters for complex 3 are listed in Table 3. The
complex [Pt{CH2-C6H4P(o-tolyl)2-C,P}(S2CNMe2)]‚CHCl3 crys-
tallizes in space group P21/c with Z ) 4. A parallelepiped-
shaped crystal mounted on the tip of a glass fiber with epoxy
cement was used for geometric and intensity data collection.
Four circle diffractometer data were taken at 293 ( 1 °C.
Lattice dimensions and type were determined by routine
procedures and verified by oscillation photography. Cell
constants were refined from 2θ values of 48 reflections
including Friedel pairs (27.7 < 2θ < 29.5°). During intensity
(28) (a) Hartley, F. R. Organomet. Chem. Rev. A 1970, 6, 119. (b)
Uchiyama, T.; Toshiyasu, Y.; Nakamura, Y.; Miwa, T.; Kawaguchi, S.
Bull. Chem. Soc. J pn. 1981, 54, 181.

C,P-Cyclometalated Compounds of Pt(II) and Pt(IV)
Organometallics, Vol. 15, No. 7, 1996 1833
data collection, three monitor reflections were measured at
regular intervals. These check reflections did not vary ap-
preciably in intensity during the course of data collection. For
the diffractometer data a measured absorption correction was
applied, based on 10 complete Ψ-scans of reflections with
diffractometer angle ø near 90°.
The structure of compound 3 was solved by direct methods
and developed and refined in series of alternating difference
Fourier maps and least-squares analyses using all data and
the program SHELXTL-PLUS.29 The chlorine atoms of the
chloroform solvent were disordered over two sites (occupancy
0.5) sharing the same C atom. The C-Cl distances were fixed
at 1.77 Å. All non-hydrogen atoms were refined anisotropi-
cally. All hydrogen atoms were included in calculated posi-
tions and refined as riding atoms [C-H ) 0.96 Å and U )
0.0872 Å3]. Residuals and other final refinement parameters
are listed in Table 3.
[P t{CH2C6H4P (o-tolyl)2-C,P }(S2CNMe2)I2]‚1/2CH2Cl2 (7).
Important crystal data and data collection parameters for
complex 7 are listed in Table 3. Diffraction data were
measured by Crystalytics Co.30 The complex [Pt{CH2-C6H4P(o-
tolyl)2-C,P}(S2CNMe2)I2]‚1/2CH2Cl2 crystallizes in space group
P21/c with Z ) 4. A parallelepiped-shaped crystal mounted
on the tip of a glass fiber with epoxy cement was used for
geometric and intensity data collection. Four-circle diffracto-
meter data were taken at 293 ( 1 °C. Lattice dimensions and
type were determined by routine procedures and verified by
oscillation photography. Cell constants were refined from 2θ
values of 15 reflections including Friedel pairs (20 < 2θ < 30°).
During intensity data collection, six monitor reflections were
measured at regular intervals. These check reflections did not
vary appreciably in intensity during the course of data
collection. For the diffractometer data a measured absorption
correction was applied, based on 6 complete Ψ-scans of
reflections with diffractometer angle ø near 90°.
The structure of compound 7 was solved by direct methods
and developed and refined in series of alternating difference
Fourier maps and least-squares analyses using all data and
the program SHELXTL-PLUS.29 The solvent molecule lays
near an inversion center and is disordered over two positions.
The occupancy of the atoms of the solvent molecule was fixed
at 0.5. All non-hydrogen atoms except for those of the solvent
were refined anisotropically. All hydrogen atoms except for
the solvent one were included in calculated positions and
refined as riding atoms [C-H ) 0.96 Å and U ) 0.0832 Å3]. A
difference map following convergence showed two peaks higher
than 1 e/Å3 (1.39 and 1.21 e/Å3). These two peaks lay very
close to the platinum atoms (0.91 and 0.95 Å) and had no
chemical significance. Residuals and other final refinement
parameters are listed in Table 3.
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 (Proyect PB92-0364) and Dr. B. Menjo´n for
his very valuable comments.
Su p p or tin g In for m a tion Ava ila ble: Tables of anisotro-
pic thermal parameters, H positional and thermal parameters,
and complete bond distances and bond angles (8 pages).
Ordering information is given on any current masthead page.
(29) SHELXTL-PLUS: Software Package for the Determination of
Crystal Structures, Release 4.0; Siemens Analytical X-ray Instruments,
Inc.: Madison, WI, 1990.
(30) Crystalytics Co., P.O. Box 82286, Lincoln, NE.
OM950861U