Syntheses and structures of monoplatinum model complexes for diplatinum polyynediyl adducts LnPt(CC)zPtLn

Article abstract of DOI:10.1016/S0022-328X(01)01311-0

The CuI-catalyzed reactions of trans-(Ph₃P)₂PtCl₂ with HCCSiMe₃ or HCCCCSiMe₃ (greater than two equivalents, HNEt₂), and trans-(p-tol)(Ph₃P)₂PtCl (4) or trans-(C₆

Full text of DOI:10.1016/S0022-328X(01)01311-0

Journal of Organometallic Chemistry 641 (2002) 53–61
www.elsevier.com/locate/jorganchem
Syntheses and structures of monoplatinum model complexes for
diplatinum polyynediyl adducts LnPt(CꢀC)zPtLn
Thomas B. Peters a, Qinglin Zheng b, Ju¨rgen Stahl b, James C. Bohling a,
Atta M. Arif a, Frank Hampel b, J.A. Gladysz b,*
a Department of Chemistry, Uni6ersity of Utah, Salt Lake City, UT 84112, USA
b Institut fu¨r Organische Chemie, Friedrich-Alexander-Uni6ersita¨t Erlangen-Nu¨rnberg, Henkestrasse 42, 91054 Erlangen, Germany
Received 6 May 2001; accepted 14 August 2001
Abstract
The CuI-catalyzed reactions of trans-(Ph3P)2PtCl2 with HCꢀCSiMe3 or HCꢀCCꢀCSiMe3 (greater than two equivalents, HNEt2),
and trans-(p-tol)(Ph3P)2PtCl (4) or trans-(C6F5)(p-tol3P)2PtCl with HCꢀCCꢀCH, give trans-(Ph3P)2Pt(CꢀCSiMe3)2 (2), trans-
(Ph3P)2Pt(CꢀCCꢀCSiMe3)2 (3), trans-(p-tol)(Ph3P)2PtCꢀCCꢀCH (5), and trans-(C6F5)(p-tol3P)2PtCꢀCCꢀCH (7) in 74–81% yields.
These compounds are characterized crystallographically, and their physical properties compared. A convenient three-step synthesis
of 4 from (COD)PtCl2 is described. © 2002 Elsevier Science B.V. All rights reserved.
Keywords: Platinum; Alkynyl and butadiynyl complexes; Hagihara coupling; Crystal structures
numerous fascinating physical and chemical properties.
In many cases, interactions between the metals or end-
1. Introduction
groups — which may be like or unlike — play key
roles. In order to analyze endgroup–endgroup interac-
tions accurately, properties of monometallic model
complexes LnMCxRm must be precisely defined. Two
recent papers provide good illustrations. The first, a
collaboration of our group and Lapinte’s [4], details a
variety of manifestations of iron–rhenium interactions
as a function of the oxidation state in heterobimetallic
C4 complexes [(h5-C5Me5)Re(NO)(PPh3)(C4)(h2-dppe)-
Fe(h5-C5Me5)]n+nPF6− (n=0–2). Analyses required
many measurements on monoiron and monorhenium
model compounds, and the analogous diiron and dirhe-
nium C4 complexes. The second is a theoretical analysis
of odd carbon-chain complexes [(h5-C5R5)(NO)-
This special issue of J. Organomet. Chem. celebrates
a Symposium hosted by the Chemistry Department of
the University of Heidelberg on the subject ‘Interac-
tions of p Systems with Metals’. This rich theme has
received particular attention in Heidelberg for some
time, and many of the pioneering contributions of these
accomplished scientists to one of whom this paper is
dedicated are detailed elsewhere in this volume. We
have had a sustained interest in this topic, involving
subjects such as chiral recognition in p complexes of the
chiral rhenium Lewis acid [(h5-C5H5)Re(NO)(PPh3)]+
[1], or more recently complexes in which sp carbon
chains span two transition metals, LnMCxM%L% [2].
n%
This contribution deals with complexes relevant to the
second subject, which has also been of great interest in
other laboratories [3].
(PR%)ReCxMLn]n+ (x=3, 5, 7, 9), some of which have
3
been prepared and the others that remain to be synthe-
sized [5]. Structural, electronic, and thermodynamic
data revealed strong metal–metal interactions in some
cases (MLn=Mn/Re(CO)2(h5-C5H5)), but not the oth-
ers (MLn=W(OMe)3).
Compounds of the formula LnMCxM%L% can exist in
n%
a variety of valence forms (e.g. MꢁC, MꢂC, or MꢀC
systems) and electronic ground states. They exhibit
We have recently communicated a new series of
PtCxPt complexes (x=8, 12, 16) with polyynediyl
chains and (p-tol)(Ph3P)2Pt, (p-tol)(p-tol3P)2Pt, or
* Corresponding author. Tel.: +49-9131-85-22540; fax: +49-
9131-85-26865.
E-mail address: gladysz@organik.uni-erlangen.de (J.A. Gladysz).
0022-328X/02/$ - see front matter © 2002 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)01311-0

54
T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
(C6F5)(p-tol3P)2Pt endgroups (see I) [6–8]. This series
of compounds, which features p and s interactions
between platinum and (CꢀC)z or (CꢀC)zPt segments, is
rapidly being extended, as detailed in our oral contribu-
tion to this symposium. Thus, there is a distinct need
for the synthesis and physical characterization of
monoplatinum model complexes. In this paper, we
report the syntheses, spectroscopic characterization,
and crystal structures of four such species, two of which
apply to the above PtCxPt systems and two of which
anticipate our future efforts in this area.
trans stereochemistry followed from the NMR data,
1
which featured diagnostic J(31P,195Pt) values [10] and
virtual coupling patterns of the phenyl 13C signals [11].
A
similar reaction of 1 and easily prepared
HCꢀCCꢀCSiMe3 [12] gave the analogous bis(1,3-diynyl)
complex trans-(Ph3P)2Pt(CꢀCCꢀCSiMe3)2 (3) in 79%
yield (Scheme 1). Interestingly, 3 was first obtained as a
by-product in the analogous reaction of the monochlo-
ride complex trans-(p-tol)(Ph3P)2PtCl (4) and
HCꢀCCꢀCSiMe3 (HNEt2, cat. CuI). In a formal sense,
this requires a protolytic cleavage of the p-tolyl ligand
by the acidic HCl or [H2NEt2]+Cl− by-product, fol-
lowed by the platinum–carbon bond formation.
The complex trans-(p-tol)(Ph3P)2PtCl (4) has been
previously synthesized [13], but by the thermal isomer-
ization of the cis isomer. We therefore describe a more
direct sequence, shown in Scheme 2. First, the reaction
of (COD)PtCl2 [14] and commercial p-tolMgBr (2.5
equivalents) gave (COD)Pt(p-tol)2 (65%), a conversion
previously effected with the tin reagent p-tolSnMe3 [15].
In an approach used earlier for alkyl chloride com-
plexes (R)(COD)PtCl [14], acetyl chloride (1.0–1.7
equivalents) and methanol were added, generating HCl.
Workup gave (p-tol)(COD)PtCl (75–94%), a com-
pound previously obtained from (COD)PtCl2 and one
equivalent of p-tolSnMe3 [15]. Subsequent reaction with
PPh3 afforded 4 in 94% yield (Scheme 2). A HNEt2
solution of 4 and CuI (7 mol%) was treated with an
excess of easily generated HCꢀCCꢀCH [16] in THF.
Workup gave the target 1,3-butadiynyl complex trans-
(p-tol)(Ph3P)2PtCꢀCCꢀCH (5) in 93% yield.
(1)
2. Results
As shown in Scheme 1, the commercially available
dichloride complex trans-(Ph3P)2PtCl2 (1) was sus-
pended in the amine solvent HNEt2. An excess of
commercial HCꢀCSiMe3 and a catalytic amount of CuI
were added. The mixture was stirred at 60 °C, and
workup gave the bis(alkynyl) complex trans-
(Ph3P)2Pt(CꢀCSiMe3)2 (2) in 74% yield. Similar condi-
tions have been used to prepare many other platinum
alkynyl species [9]. Complex 2, and all new compounds
below, were characterized by microanalysis, and IR and
NMR (1H, 13C, 31P) spectroscopies (Section 4). The
Scheme 1. Syntheses of Pt(CꢀC)zSiMe3 complexes.
Scheme 2. Synthesis of a p-tolyl 1,3-butadiynyl complex.

T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
55
Scheme 3. Synthesis of a pentafluorophenyl 1,3-butadiynyl complex.
Table 1
Summary of crystallographic data
Complex
2
3·ethanol
5
7
Empirical formula
Diffractometer
Temperature (K)
C
46H48P2PtSi2
C52H54OP2PtSi2
Nonius KappaCCD
200(0.1)
C47H38P2Pt
Nonius CAD4
291(2)
C52H43F5P2Pt
Nonius KappaCCD
173(2)
Nonius KappaCCD
200(0.1)
,
Wavelength (A)
0.71073
Triclinic
0.71073
Monoclinic
I2/a
0.71073
Triclinic
0.71073
Triclinic
Crystal system
Space group
(
(
(
P1
P1
P1
Unit cell dimensions
,
a (A)
7.7736(4)
12.0982(4)
12.1277(5)
79.091(2)
75.2346(14)
74.468(2)
1053.50(8)
1
14.4899(9)
14.2589(6)
23.7535(14)
90
102.651(2)
90
4788.6(5)
4
1.398
10.507(7)
10.6886(15)
18.149(6)
102.278(18)
83.75(4)
105.66(2)
1914.8(14)
2
13.0595(3)
14.6995(3)
14.7397(3)
114.500(1)
99.310(1)
110.010(1)
2261.61(8)
2
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
V (A )
3
,
Z
Dcalc (g cm−3
)
1.441
1.491
1.498
Absorption coefficient
3.493
3.083
3.779
3.228
(mm−1
)
Crystal size (mm3)
Theta range for data
collection (°)
0.28×0.25×0.15
3.60–22.66
0.23×0.18×0.12
1.68–24.75
0.40×0.30×0.30
4.10–27.52
2.02–24.97
Index ranges
05h58, −125k512, 05h517, −165k516, 05h512, −125k512,
−155h516, −195k517,
−195l519
15 748
−125l513
2689
−275l527
5482
−215l521
7149
Reflections collected
Independent reflections
Reflections [I\2|(I)]
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I\2|(I)]
2689
2689
2689/–/233
1.060
R1=0.0194;
wR2=0.0498
R2=0.0194;
wR2=0.0498
1.077 and −0.697
3460
2923
3460/–/268
1.105
R1=0.0371;
wR2=0.0853
R1=0.0473;
wR2=0.0927
1.522 and −1.046
6744
6119
6119/–/451
1.099
R1=0.0267;
wR2=0.0696
R1=0.321;
wR2=0.0720
0.862 and −0.680
10 287
9548
10 287/1/541
1.033
R1=0.0299;
wR2=0.0780
R1=0.0337;
wR2=0.0810
1.671 and −2.460
R indices (all data)
Largest difference peak and
3−
,
hole (e A
)
The pentafluorophenyl tetrahydrothiophene (SR2)
complex [(C6F5)Pt(SR2)(m-Cl)]2 [17] has been shown
earlier to react with phosphines to give species of the
formula trans-(C6F5)(L)2PtCl [10a,18]. As shown in
Scheme 3, reaction with p-tol3P gave the bis(phosphine)
complex trans-(C6F5)(p-tol3P)2PtCl (6) in 93% yield
after workup. Reaction with HNEt2, CuI, and
HCꢀCCꢀCH as with 4 gave the target 1,3-butadiynyl
complex trans-(C6F5)(p-tol3P)2PtCꢀCCꢀCH (7) in 81%
yield.
Section 4. The X-ray structures were determined, and
general data are summarized in Table 1. The corre-
sponding ORTEP diagrams, which confirm the structural
assignments, are given in Figs. 1–4. The key bond
lengths and bond angles are given in Table 2. The
13C-NMR spectra of 3, 5, and 7 showed CꢀCCꢀC
signals with chemical shift patterns analogous to those
of the other 1,3-butadiynyl and 1,3-silylbutadiynyl plat-
inum and rhenium complexes [2e,6,7]. The UV–vis
spectrum of the bis(1,3-butadiynyl) complex 3 exhibited
bands at 319 and 339 nm (m 12 000 and 26 400
Complexes 2, 3, 5, and 7 were white to pale yellow
air-stable powders. Crystals were grown as described in
M
−1 cm−1, CH2Cl2). In contrast, the mono(1,3-bu-

56
T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
Fig. 1. Molecular structure of trans-(Ph3P)2Pt(CꢀCSiMe3)2 (2).
Fig. 4. Molecular structure of trans-(C6F5)(p-tol3P)2PtCꢀCCꢀCH (7).
tadiynyl) complex 5 and the p-tol3P analog trans-(p-
tol)(p-tol3P)2PtCꢀCCꢀCH [6] gave only a single weak
band at 320–321 nm (m 3800–2000 M−1 cm−1). Com-
plex 7 was similar (305 nm, m 5800 M−1 cm−1).
3. Discussion
Three of our model monoplatinum complexes, 3, 5,
and 7, feature 1,3-diynyl ligands. This class of com-
pounds has been comprehensively reviewed recently by
Low and Bruce [19]. They tabulate eight other platinu-
m(II) bis(1,3-diynyl) complexes with two monophos-
phine ligands, nearly all of which are trans as in 3 and
5. Only one of these, trans-(n-Bu3P)2Pt(CꢀCCꢀCH)2 (8;
Chart 1) [20], has been crystallographically character-
ized, as verified by an independent search of the Cam-
bridge data base. We previously reported the similar
synthesis and structural characterization of a relevant
mono(1,3-butadiynyl) complex, trans-(p-tol)(Ph3P)2-
PtCꢀCCꢀCSiMe3 (9; Chart 1) [8]. For ease of compari-
son, the key metrical parameters for 8 and 9 are given
in Table 2.
Fig. 2. Structure of trans-(Ph3P)2Pt(CꢀCCꢀCSiMe3)2·ethanol
(3·ethanol) with the solvate omitted.
Many platinum(II) alkynyl complexes LnPtCꢀCR
(R"CꢀCR%) have been characterized crystallographi-
cally, and we do not attempt to summarize this litera-
ture, for which partial surveys are available [9,21,22].
However, we have determined the crystal structure of
trans-(p-tol)(Ph3P)2PtCꢀCSiMe3 (10; Chart 1) [8]. Since
this represents another obvious reference complex for 2,
3, 5, and 7, key data are also added to Table 2. All the
platinum 1,3-diynyl complexes tabulated by Low and
Bruce contain trialkyl or dialkylphenyl-monophosphine
Fig. 3. Molecular structure of trans-(p-tol)(Ph3P)2PtCꢀCCꢀCH (5).

T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
57
Table 2
Comparison of key bond lengths and angles in monoplatinum complexes
Complex
2
3
5
7
8 [20]
1.984(5)
1.211(7)
1.372(8)
1.159(8)
2.301(1)
2.300(2)
–
10 [8]
2.035(5)
1.186(7)
–
9 [8]
2.039(15)
1.196(18)
1.37(2)
1.196(18)
2.302(3)
2.311(3)
2.080(13)
PtꢁCꢀ
PtꢁCꢀC
PtꢁCꢀCꢁC
PtꢁCꢀCꢁCꢀC
PtꢁP1
2.004(3)
1.207(5)
–
–
2.3113(8)
2.3113(8)
–
2.005(7)
1.201(9)
1.373(9)
1.206(9)
2.3108(15)
2.3108(15)
–
2.009(4)
1.216(6)
1.380(6)
1.183(7)
2.2918(12)
2.2931(12)
2.077(4)
2.004(3)
1.201(5)
1.381(5)
1.184(6)
2.3181(7)
2.3027(7)
2.060(3)
–
2.2916(13)
2.2998(13)
2.057(4)
PtꢁP2
Pt–aryl
CꢁPtꢁCꢀ
P1ꢁPtꢁCꢀ
P2ꢁPtꢁCꢀ
P1ꢁPtꢁP2
PtꢁCꢀC
PtꢁCꢀCꢁX
PtꢁCꢀCꢁCꢀC
PtꢁCꢀCꢁCꢀCꢁSi
180.00(15)
87.07(9)
92.93(9)
180.0
175.8(3)
175.6(3)
–
180.00(16)
85.73(17)
94.27(17)
180.0
177.4(6)
178.8(7)
177.8(7)
171.5(7)
176.44(15)
87.14(12)
92.80(13)
178.17(4)
175.9(4)
175.6(5)
178.1(6)
–
176.81(12)
90.90(9)
87.11(9)
173.98(3)
175.0(3)
179.1(5)
179.0(6)
–
180.0
176.8(2)
175.2(5)
90.7(4)
93.4(4)
172.45(12)
175.0(11)
178.1(14)
176.8(15)
174.0(13)
91.9(1)
88.2(1)
180.0
178.5(5)
176.0(6)
179.4(9)
–
88.11(14)
86.34(14)
174.43(4)
174.2(5)
172.3(6)
–
–
–
The nature of metal–p interactions in metal–alkynyl
complexes has been examined by a number of spectro-
scopic, structural, and computational probes [21,24].
An analysis of this complicated subject is beyond the
scope of this paper. However, photoelectron spec-
troscopy and DFT calculations indicate modest p acid-
ity, with pronounced interactions between the occupied
metal d and ligand p orbitals in 18 valence electron
complexes. Sixteen valence electron platinum alkynyl
complexes exhibit UV absorptions arising from both
p“CꢀCp* intra-ligand transitions and metal d“
CꢀCp* MLCT transitions [25]. Analogs of 2 which
contain donor- and acceptor-substituted phenylalkynyl
ligands exhibit NLO properties [22].
Turning to the synthetic aspects of this study, the
sequences in Schemes 2 and 3 allow rapid access to a
variety of bis(phosphine) complexes of the types trans-
(p-tol)(R3P)2PtCl and trans-(C6F5)(R3P)2PtCl. The
yields of most steps are not optimized, and represent
realistic outcomes for ‘first time’ experiments. These
complexes are seeing extensive use as precursors to a
variety of novel LnPt(CꢀC)zPtLn systems [26], and C8,
C12, and C16 complexes derived from 5 and/or 7 have
already been reported [6,7]. Protio analogs of the sily-
lated complexes 2 and 3 are precursors to polymers
with [Pt(CꢀC)z]y repeat units [27]. All these themes as
well as the others will be represented in future papers
from our laboratory.
ligands, whereas ours feature triarylphosphines ligands.
Trialkylphosphines can displace triarylphosphines from
platinum alkynyl complexes [23], and this reactivity
mode plays a key role in certain chemical applications
of our compounds.
Turning to the data in Table 2, there is a striking
similarity of bond lengths and bond angles. The PtꢁCꢀ
distance in the bis(trialkylphosphine) complex 8 is
slightly shorter than the others (1.984(5) vs. 2.004(3)–
,
2.035(5) or 2.039(15) A). The bis(alkynyl) and bis(1,3-
diynyl) complexes have linear ꢀCꢁPtꢁCꢀ linkages
(180.0° for 2, 3, 8), whereas the (aryl)Pt(CꢀC) com-
plexes have slightly bent CꢁPtꢁCꢀ linkages (175.2(5)–
176.8(2)° for 5, 7, 9, 10). Other trends can be identified,
but all lengths and angles have the estimated standard
deviations. When the difference between the two com-
pounds is less than three times the standard deviations,
rigorous conclusions are not possible. However, when
parallel differences are noted for a series of compounds,
there is additional confidence of a genuine trend. In this
context, note that both 2 and 3 give PtꢁCꢀ distances
shorter than the analogs 9 and 10 (2.004(3)–2.005(7) vs.
,
2.035(5)–2.039(15) A), implicating an effect of the trans
ligand upon s and p interactions. Other such relation-
ships can be seen in Table 2, and are currently being
tested by DFT calculations, which often give remark-
ably accurate bond lengths and angles.
4. Experimental
4.1. General
Reactions were conducted under N2 atmospheres.
Commercial chemicals were treated as follows: ether,
distilled from Na–benzophenone; HNEt2, distilled
from KOH; p-tolMgBr (Aldrich, 1.0 M in ether), stan-
Chart 1. Related structurally characterized complexes.

58
T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
dardized [28]; trans-(Ph3P)2PtCl2 (Aldrich [29]),
HCꢀCSiMe3 (Farchan or GFS), CuI (Aldrich,
99.999%), acetyl chloride, and other materials, used as
received. IR spectra were recorded in Mattson Polaris
FT or ASI ReactIR-1000 spectrometers. UV–vis spec-
tra were recorded on a Shimadzu model 3102 spectrom-
eter. NMR spectra were recorded on standard 300–500
MHz FT spectrometers. Mass spectra were recorded on
a Finnigan MAT 95 high-resolution instrument. Micro-
analyses were conducted by Atlantic Microlab or with a
Carlo Erba EA1110 instrument (in-house).
(CH2Cl2, 1.25×10−6 M): 319 (12 000), 339 (26 400).
1H-NMR (CDCl3, l ppm): 7.75–7.35 (m, 6C6H5), 0.05
(s, 6CH3). 13C{1H}-NMR (l ppm): 135.2 (virtual t,
1
2JCP=6.0 Hz [11], o-Ph), 130.5 (virtual t, JCP=29.7
3
Hz [11], i-Ph), 130.8 (s, p-Ph), 128.2 (virtual t, JCP
=
5.5 Hz [11], m-Ph), 105.8 (s, CꢀCCꢀCSi), 95.9, 93.5 (2
s, CꢀCCꢀC), 77.7 (s, CꢀCSi), 0.8 (s, SiCH3). 31P{1H}-
1
NMR (l ppm): 18.8 (s, JPPt=2572 Hz [30a]).
4.4. (COD)Pt(p-tol)2 [14]
A Schlenk flask was charged with (COD)PtCl2 (2.005
g, 5.35 mmol) [14] and ether (30 ml). Then p-tolMgBr
(1.0 M in ether; 13.4 ml, 13 mmol) was added with
stirring. After 16 h, saturated aq. NH4Cl (25 ml) was
added. The ether layer was separated, and the water
layer extracted with ether (3×50 ml). The combined
ether extracts were dried (MgSO4), and filtered through
a 1 cm Celite® pad and a 2 cm decolorizing carbon pad.
The ether was removed from the filtrate under a N2
stream. The white solid was suspended in EtOH (25
ml), collected by filtration, and dried by oil pump
vacuum to give (COD)Pt(p-tol)2 (1.685 g, 3.46 mmol,
4.2. trans-(Ph3P)2Pt(CꢀCSiMe3)2 (2)
A Schlenk flask was charged with trans-(Ph3P)2PtCl2
(0.500 g, 0.63 mmol) [29], HNEt2 (30 ml), CuI (0.020 g,
0.10 mmol), and HCꢀCSiMe3 (0.270 ml, 2.2 mmol).
The suspension was first stirred at 60 °C (0.5 h) and
then at room temperature (r.t.) (14 h). The solvent was
evaporated under a N2 stream, and the dark residue
taken up in CH2Cl2–H2O. The organic layer was sepa-
rated, dried (MgSO4), and taken to dryness by rotary
evaporation. The residue was taken up in a small
amount of CHCl3, and added to 100 ml of rapidly
stirred EtOH. The precipitate was isolated on a
medium porosity frit and dried under oil pump vacuum
to give 2 as a white solid (0.430 g, 0.47 mmol, 74%).
Anal. Calc. for C46H48P2PtSi2: C, 60.46; H, 5.26.
Found: C, 60.28; H, 5.24%. IR (cm−1, CH2Cl2): wCꢀC
2058 (w, sh), 2038 (s). 1H-NMR (CDCl3, l ppm ):
7.4–7.8 (m, 6C6H5), −0.45 (s, 6CH3). 13C{1H}-NMR
1
3
65%). H-NMR (CDCl3, l ppm): 7.12 (d, JHH=10.5
3
3
Hz, JHPt=67.8 Hz [30a], 4H/o to Pt), 6.85 (d, JHH
=
2
10.3 Hz, 4H/m to Pt), 5.10 (s, JHPt=24.2 Hz [30a],
4CH2CHꢂ), 2.45–2.60 (m, 4CH2), 2.18 (s, 2CH3).
4.5. (p-tol)(COD)PtCl [14]
A Schlenk flask was charged with (COD)Pt(p-tol)2
(1.010 g, 2.06 mmol), CH2Cl2 (15 ml), and MeOH (15
ml). Acetyl chloride (0.14 ml, 2.0 mmol) was added
with stirring. After 15 min, solvent was removed by
rotary evaporation. The white residue was suspended in
MeOH (15 ml), collected by filtration, and dried by oil
pump vacuum to give (p-tol)(COD)PtCl (0.660 g, 1.54
2
(CDCl3, l ppm): 135.5 (virtual t, JCP=6.0 Hz [11],
1
o-Ph), 131.8 (virtual t, JCP=31.5 Hz [11], i-Ph), 130.3
3
(s, p-Ph), 127.8 (virtual t, JCP=5.6 Hz [11], m-Ph),
117.8 (s, CꢀCSi), 58.2 (s, CꢀCSi), 0.6 (s, SiCH3).
31P{1H}-NMR (CDCl3, l ppm): 18.8 (s, 1JPPt=2568
Hz [30a]).
1
mmol, 75% [31]). H-NMR (CDCl3, l ppm): 7.10 (d,
3
4.3. trans-(Ph3P)2Pt(CꢀCCꢀCSiMe3)2 (3)
3JHH=10.5 Hz, JHPt=42.9 Hz [30a], 2H/o to Pt), 6.92
3
2
(d, JHH=10.5 Hz, 2H/m to Pt), 5.80 (m, JHPt=13.5
Hz [30a], 2CH2CHꢂ), 4.60 (m, 2JHPt=21 Hz [30a],
2C%H2C%Hꢂ), 2.30–2.80 (m, 4CH2), 2.25 (s, CH3).
A Schlenk flask was charged with trans-(Ph3P)2PtCl2
(0.079 g, 0.10 mmol) [29], HNEt2 (15 ml), CuI (0.006 g,
0.03 mmol), HCꢀCCꢀCSiMe3 (0.061 g, 0.50 mmol) [12],
and CH2Cl2 (5 ml), and fitted with a condenser. The
suspension was stirred at r.t. (3 h) and then 80 °C (oil
bath, 2 h). The solvent was removed by rotary evapora-
tion. The dark residue was extracted with toluene (2×
25 ml). The extract was filtered through alumina (7 cm),
and the solvent was removed by rotary evaporation.
The residue was suspended in MeOH (5 ml), and the
slightly yellow solid collected by filtration and dried by
oil pump vacuum to give 3 (0.076 g, 0.079 mmol, 79%),
m.p. (dec.) 239–242 °C (decolorization \176 °C).
Anal. Calc. for C50H48P2PtꢁSi2: C, 62.42; H, 5.03.
Found: C, 61.96; H, 5.39%. IR (cm−1, CH2Cl2): wCꢀC
4.6. trans-(p-tol)(Ph3P)2PtCl (4) [13]
A Schlenk flask was charged with (p-tol)(COD)PtCl
(0.662 g, 1.54 mmol), Ph3P (0.814 g, 3.10 mmol), and
CH2Cl2 (30 ml). The mixture was stirred for 16 h. The
solvent was removed under a N2 stream. The white
residue was suspended in MeOH (10 ml), collected by
filtration, washed with hexanes (5 ml), and dried by oil
pump vacuum to give 4 (1.215 g, 1.45 mmol, 94%).
Crystallization (CHCl3–MeOH layer–layer diffusion)
1
gave small white needles, m.p. (dec.) 295 °C. H-NMR
(CDCl3, l ppm): 7.15–7.60 (m, 6C6H5), 6.45 (d, 3JHH
12.2 Hz, JHPt=50.0 Hz [30a], 2H/o to Pt), 5.95 (d,
=
3
2185 (m), 2131 (s). UV–vis: u (nm) (m, M−1 cm−1
)

T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
59
3JHH=10.9 Hz, 2H/m to Pt), 1.90 (s, CH3). 13C{1H}-
NMR (CDCl3, l ppm): 136.9 (s, i to Pt), 135.0 (virtual
t, JCP=6.0 Hz [11], o-Ph), 130.6 (virtual t, JCP=27.8
(tol3P+, 100%). 1H-NMR (CDCl3, l ppm): 7.51 (m,
3
12H/o to P), 7.09 (d, JHH=7.8 Hz, 12H/m to P), 2.33
(s, 6CH3). 13C{1H}-NMR (CDCl3, l ppm): 145.2 (dd,
2
1
2
Hz [11], i-Ph), 130.4 (s, p to Pt), 123.0 (s, p-Ph), 128.9
1JCF=225 Hz, JCF=21 Hz, o to Pt), 140.7 (s, p to P),
3
1
1
(s, o to Pt), 128.4 (s, m to Pt), 127.9 (virtual t, JCP
=
136.9 (dm, JCF=241 Hz, p to Pt), 136.2 (dm, JCF=
5.2 Hz [11], m-Ph), 20.4 (s, CH3). 31P{1H}-NMR
(CDCl3, l ppm): 24.6 (s, JPPt=3155 Hz [30a]).
245 Hz, m to Pt), 134.4 (virtual t, JCP=6.5 Hz [11], o
2
1
3
to P), 128.7 (virtual t, JCP=6.0 Hz [11], m to P), 126.6
1
(virtual t, JCP=29.7 Hz [11], i to P), 21.3 (s, CH3).
1
4.7. trans-(p-tol)(Ph3P)2PtCꢀCCꢀCH (5)
31P{1H}-NMR (l ppm): 19.9 (s, JPPt=2728 Hz [30a]).
A Schlenk flask was charged with 4 (1.500 g, 1.77
mmol), CuI (0.023 g, 0.12 mmol), and HNEt2 (100 ml),
and cooled to −45 °C. Then HCꢀCCꢀCH (2.0 M in
THF; 25 ml, 50.0 mmol) [32] was added with stirring.
After 1.5 h, the cold bath was removed. After 1 h,
solvent was removed by rotary evaporation. The
residue was extracted with benzene (2×25 ml). The
combined extracts were filtered through an alumina
column (7 cm). Solvent was removed by rotary evapo-
ration. Ethanol (15 ml) was added, and the pale tan
powder was collected by filtration and dried by oil
pump vacuum to give 5 (1.422 g, 1.65 mmol, 93%), m.p.
(dec.) 182 °C. Anal. Calc. for C47H38P2Pt: C, 65.65; H,
4.45. Found: C, 65.47; H, 4.46%. IR (cm−1, CH2Cl2):
wꢀCH 3310 (w), wCꢀC 2143 (s). UV-vis: u (nm) (m,
4.9. trans-(C6F5)(p-tol3P)2PtCꢀCCꢀCH (7)
A Schlenk flask was charged with 6 (1.560 g, 1.550
mmol), CuI (0.060 g, 0.32 mmol), CH2Cl2 (10 ml), and
HNEt2 (100 ml), and cooled to −45 °C. Then
HCꢀCCꢀCH (2.9 M in THF; 8.6 ml, 24.9 mmol) [32]
was added with stirring. The cold bath was allowed to
warm to r.t. (ca. 3 h). After an additional 2.5 h, the
solvent was removed by oil pump vacuum. The residue
was extracted with toluene (3×20 ml). The combined
extracts were filtered through an alumina column (7
cm). The solvent was removed by rotary evaporation.
Ethanol (20 ml) was added, and the off-white solid was
collected by filtration and dried by oil pump vacuum to
give 7 (1.275 g, 1.250 mmol, 81%), m.p. (dec.) \
171 °C. Anal. Calc. for C52H43F5P2Pt: C, 61.24; H,
4.25. Found: C, 60.83; H, 4.31% IR (cm−1, powder
film): wꢀCH 3320 (w), wCꢀC 2154 (m). UV–vis: u (nm) (m,
M
−1 cm−1) (CH2Cl2, 1.25×10−5 M): 321 (3800). MS
(positive FAB, 3-NBA/THF, m/z): 859 (5+, 30%), 810
((tol)(PPh3)2Pt+, 80%), 719 ((PPh3)2Pt+, 100%); no
1
other peaks above 400 of \3%. H-NMR (CDCl3, l
M
−1 cm−1) (CH2Cl2, 1.25×10−5 M): 305 (5800). MS
3
ppm): 7.51–7.24 (m, 6C6H5), 6.34 (d, JHH=7.8 Hz,
(positive FAB, 3-NBA, m/z): 1020 (7+, 26%), 970
((C6F5)(tol3P)2Pt+, 72%), 851 ((tol3P)2PtCꢀCCꢀCH+,
23%), 803 ((tol3P)2Pt+, 100%). 1H-NMR (CDCl3, l
3
3JHPt=55.3 Hz [30a], 2H/o to Pt), 6.08 (d, JHH=7.5
Hz, 2H/m to Pt), 1.92 (s, CH3), 1.41 (t, JHP=0.9 Hz,
ꢀCH). 13C{1H}-NMR (CDCl3, l ppm): 149.9 (s, i to
ppm): 7.49 (m, 12H/o to P), 7.10 (d, JHH=7.4 Hz,
3
2
Pt), 139.5 (s, o to Pt), 135.4 (virtual t, JCP=6.1 Hz
12H/m to P), 2.34 (s, 6CH3), 1.46 (s, ꢀCH). 13C{1H}-
NMR (CDCl3, l ppm): 145.8 (dd, 1JCF=224 Hz,
2JCF=22 Hz, o to Pt), 140.7 (s, p to P), 136.8 (dm,
1
[11], o-Ph), 131.6 (virtual t, JCP=28.7 Hz [11], i-Ph),
130.5 (s, p-Ph), 130.3 (s, p to Pt), 128.8 (s, m to Pt),
128.3 (virtual t, 3JCP=5.4 Hz [11], m-Ph), 110.7 (s,
PtCꢀC) [30b,33], 96.3 (s, PtCꢀC) [33], 73.3 (s, CꢀCH)
[33], 59.2 (s, CꢀCH) [33], 21.1 (s, CH3). 31P{1H}-NMR
1
1JCF=239 Hz, p to Pt), 136.3 (dm, JCF=248 Hz, m to
2
Pt), 134.3 (virtual t, JCP=6.2 Hz [11], o to P), 128.6
3
(virtual t, JCP=5.2 Hz [11], m to P), 127.4 (virtual t,
1
(CDCl3, l ppm): 21.3 (s, JPPt=2959 Hz [30a]).
1JCP=30.2 Hz [11], i to P), 97.8 (s, 1JCPt=990 Hz,
PtCꢀC) [30a,33], 94.9 (s, 1JCPt=266 Hz, PtCꢀC)
[30a,33], 72.5 (s, CꢀCH) [33], 59.6 (s, CꢀCH) [33], 21.3
(s, CH3). 31P{1H}-NMR (CDCl3, l ppm): 17.6 (s,
1JPPt=2655 Hz [30a]).
4.8. trans-(C6F5)(p-tol3P)2PtCl (6)
A Schlenk flask was charged with [Pt(C6F5)(SR2)(m-
Cl)]2 (0.729 g, 0.750 mmol; SR2=tetrahydrothiophene)
[17], p-tol3P (1.029 g, 3.381 mmol), and CH2Cl2 (25 ml).
The solution was stirred for 16 h and filtered through a
Celite®–decolorizing carbon–glass frit assembly. The
solvent was removed by rotary evaporation. The
residue was washed with methanol (2×15 ml) and
dried by oil pump vacuum to give 6 as a white powder
(1.410 g, 1.401 mmol, 93%), m.p. (dec) \230 °C.
Anal. Calc. for C48H42ClF5P2Pt: C, 57.29; H, 4.21.
Found: C, 57.29; H, 4.34%. MS (positive FAB, 3-NBA,
m/z): 1005 (6+, 5%), 970 ((C6F5)(tol3P)2Pt+, 20%), 802
((tol3P)2Pt+, 23%), 497 ((tol3P)Pt+, 8%), 304 (100)
4.10. Crystallography
A concentrated benzene solution of 2 was carefully
layered with EtOH. After 2 weeks, long colorless
needles were obtained. Data were collected as outlined
in Table 1. Cell parameters (200(0.1) K) were obtained
from ten frames using a 10° scan. The space group was
determined from least-squares refinement. Lorentz, po-
larization, and absorption corrections were applied us-
ing DENZO-SMN and SCALEPACK [34]. The structure was
solved by standard heavy atom techniques with the

60
T.B. Peters et al. / Journal of Organometallic Chemistry 641 (2002) 53–61
(c) S.B. Falloon, S. Szafert, A.M. Arif, J.A. Gladysz, Chem. Eur.
J. 4 (1998) 1033;
(d) T. Bartik, W. Weng, J.A. Ramsden, S. Szafert, S.B. Falloon,
A.M. Arif, J.A. Gladysz, J. Am. Chem. Soc. 120 (1998) 11071;
(e) R. Dembinski, T. Bartik, B. Bartik, M. Jaeger, J.A. Gladysz,
J. Am. Chem. Soc. 122 (2000) 810;
SIR97 package and refined with SHELXL-97 [35]. Non-
hydrogen atoms were refined with anisotropic thermal
parameters. Hydrogen atom positions were calculated
and added to the structure factor calculations, using the
riding model.
(f) W.E. Meyer, A.J. Amoroso, C.R. Horn, M. Jaeger, J.A.
Gladysz, Organometallics 20 (2001) 1115.
A concentrated benzene solution of 3 was layered
with EtOH. After 1 week, a single large irregular prism
had formed. Data were collected using a piece of this
crystal. The cell parameters and space group were
determined as for 2. An identical refinement led to a
unit cell containing an EtOH molecule, the CH2OH
group of which showed displacement disorder (C45S,
O1S) that could be refined to a 50:50 occupancy ratio.
A concentrated 1,2 dichloroethane solution of 5 was
layered with hexanes. After 2 weeks, small light yellow
prisms were obtained. Cell parameters (291(2) K) were
obtained from 25 reflections with 13°B2qB14°. The
data were refined as in the previous two cases. A CHCl3
solution of 7 was layered with EtOH. After 1 week,
irregular, off-white prisms were obtained. The cell
parameters and space group were determined, and cor-
rections applied, as for 2. The structure was solved by
direct methods, and refined as for 2. In all cases,
scattering factors were taken from the literature [36].
[3] See the following lead references and papers cited therein: (a)
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5. Supplementary material
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(b) The J values given represent the apparent coupling between
adjacent peaks of the triplet.
[12] B. Bartik, R. Dembinski, T. Bartik, A.M. Arif, J.A. Gladysz, N.
J. Chem. 21 (1997) 739.
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(1978) 357.
Crystallographic data for structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 162672, 162673, 134343 and
168536 for 2, 3·ethanol, 5 and 7, respectively. Copies of
this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge,
CB2 1EZ, UK (Fax: +44-1223-336033; e-mail: de-
posit@ccdc.cam.ac.uk or www: http://www.ccdc.
cam.ac.uk).
[16] L. Brandsma, H.D. Verkruijsse, Synth. Commun. 21 (1991) 657.
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Acknowledgements
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We thank the Deutsche Forschungsgemeinschaft
(DFG, GL 300/1-1), the US NSF, and Johnson
Matthey PMC (platinum loan) for support.
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chloride is used in greater excess (COD)PtCl2 forms. The relative
amounts of (COD)Pt(p-tol)2, trans-(p-tol)(COD)Pt(p-tol), and
(COD)PtCl2 are easily assayed by 1H-NMR.
[32] The HCꢀCCꢀCH concentration is calculated from the mass
increase of the THF solution [16]. CAUTION: this compound is
explosive and literature precautions should be followed.
[33] These signals are assigned by analogy to those of the more
soluble p-tol3P analog, for which additional diagnostic couplings
(JCP, JCPt) could be observed and 1H-undecoupled spectra were
recorded [6].
[34] Z. Otwinowski, W. Minor, Methods Enzymol. A: Macromol.
Crystallogr. 276 (1997) 307.
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[26] J. Stahl, W. Mohr, Universita¨t Erlangen-Nu¨rnberg, unpublished
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M. Orchin, Inorg. Synth. 19 (1979) 114 (Alternatively, the cis
isomer of 1 (or cis/trans mixtures) can also be used to prepare
the trans complexes 2 and 3.).
[30] (a) This coupling represents a satellite (d; 195Pt=33.8%), and is
not reflected in the peak multiplicity given;
(b) A satellite would be expected based upon other spectra in this
paper, but could not be discerned above background noise.
[31] Alternatively, this procedure can be conducted with 1.7 equiva-
lents of acetyl chloride (0.5 h reaction time), giving a 94% yield.
However, if the reaction is allowed to proceed too long, or acetyl
(c) D.T. Cromer, J.T. Waber, in: J.A. Ibers, W.C. Hamilton
(Eds.), International Tables for X-ray Crystallography, 2nd ed.,
Kynoch, Birmingham, England, 1974.