Transition Metal Silyl Complexes. 62.1 Platinum Dimethyl Complexes with Hemilabile P,N-Chelating Ligands: Synthesis, Structure, and Reactions with Iodotrimethylsilane and 1,2-Bis(dimethylsilyl)benzene

Article abstract of DOI:10.1021/om990665d

Reaction of (η⁴-2,5-norbornadiene)dimethylplatinum(II) with (2-diphenylphosphinoethyl)-dimethylamine, (3-diphenylphosphinopropyl)dimethylamine, 2-diphenylphosphino-N,N-dimethylaniline, or (o-diphenylphosphinobenzyl)dimethylamine resulted in the

Full text of DOI:10.1021/om990665d

62
Organometallics 2000, 19, 62-71
Tr a n sition Meta l Silyl Com p lexes. 62.1 P la tin u m
Dim eth yl Com p lexes w ith Hem ila bile P ,N-Ch ela tin g
Liga n d s: Syn th esis, Str u ctu r e, a n d Rea ction s w ith
Iod otr im eth ylsila n e a n d 1,2-Bis(d im eth ylsilyl)ben zen e
J u¨rgen Pfeiffer, Guido Kickelbick, and Ulrich Schubert*
Institut fu¨r Anorganische Chemie, Technische Universita¨t Wien, Getreidemarkt 9,
A-1060 Wien, Austria
Received August 17, 1999
Reaction of (η4-2,5-norbornadiene)dimethylplatinum(II) with (2-diphenylphosphinoethyl)-
dimethylamine, (3-diphenylphosphinopropyl)dimethylamine, 2-diphenylphosphino-N,N-di-
methylaniline, or (o-diphenylphosphinobenzyl)dimethylamine resulted in the formation of
the corresponding dimethyl platinum complexes containing the P,N-chelating ligands, while
reaction with (diphenylphosphinomethyl)dimethylamine gave only the bis(phosphine)
complex. Reaction of the P,N-chelated dimethyl complexes with iodotrimethylsilane stereo-
selectively gave the corresponding methyl iodo complexes in which only the methyl group
trans to the phosphorus atom was exchanged. Reaction with 1,2-bis(dimethylsilyl)benzene
yielded cyclic bis(silyl) complexes. Analogous experiments with (dppe)PtMe2 revealed that
the P,N-chelated complexes exhibit a considerably higher reactivity than the bis(phosphine)
complex. The most interesting feature in the solid-state structures of [(κ2-P,N)-Ph2PC2H4-
NMe2]PtMe2, trans-[(κ2-P,N)-Ph2PC6H4-2-CH2NMe2]Pt(I)Me, and [(κ2-P,N)-Ph2PC6H4-2-
NMe2]Pt[o-(Me2Si)2C6H4] is the very long Pt-N distances (221.0(7), 223.3(6), and 236.8(5)
pm, respectively), showing that the nitrogen atom of the P,N-chelating ligand is only weakly
bonded. The Pt-C and Pt-Si distances trans to nitrogen are much shorter (203.7(9), 230.4-
(2) pm) than those trans to phosphorus (206.9(8), 237.2(2) pm).
In tr od u ction
to be hemilabile, with the nitrogen donor being rapidly
(de)coordinated, thus providing a free coordination site.7
Square planar complexes of late transition metals
With respect to the chemistry of metal silyl com-
plexes,8 the introduction of P,N-chelating ligands is of
special interest because of the potential to obtain
hitherto unknown bis(silyl) complexes bearing two
electronically different silyl ligands. This could have
interesting consequences for the reactivity of these
compounds. The most promising precursors for the
synthesis of P,N-chelated (bis)silyl complexes are the
corresponding dimethyl complexes, because of the known
ease of methyl/silyl exchange reactions.9
bearing P,N-chelating ligands (P∩N)MX2 (M ) Pd, Pt;
X: e.g., halide, alkyl) are known to allow highly stereo-
selective substitution reactions of the ligands X. The
stereochemical outcome of the ligand substitution reac-
tion can be explained by the different electronic proper-
ties of the nitrogen and phosphorus donor atoms.2 For
example, (P∩N)Pd(Br)Me (P∩N ) 2-(diphenylphosphi-
no)benzylidene-S(-)-R-methylbenzylamine) was ob-
tained by reaction of (P∩N)PdBr2 with Me4Sn with
complete trans stereoselectivity.3,4 In an analogous
reaction, trans-(P∩N)Pd(I)Me (P∩N ) (o-diphenylphos-
phinobenzyl)dimethylamine) was obtained from (P∩N)-
PdMe2 by reaction with MeI.5 Only recently, the selec-
tivity of this reaction was used to synthesize chiral
cationic phosphino-oxazoline platinum complexes by a
methyl dichloromethane exchange reaction; these com-
plexes were tested in the enantioselective epoxidation
of terminal alkenes.6 P,N-chelating ligands are known
(7) Review article on complexes with hemilabile ligands: Bader, A.;
Lindner, E. Coord. Chem. Rev. 1991, 108, 27. Recently, the reversible
decoordination of the nitrogen donor group incorporated in a P,N-
chelating ligand was directly observed by NMR spectroscopy: Go´mez-
de la Torre, F.; J alo´n, F. A.; Lo´pez-Agenjo, A.; Manzano, B. R.;
Rodr´ıguez, A.; Sturm, T.; Weissensteiner, W.; Mart´ınez-Ripoll, M.
Organometallics 1998, 17, 4634.
(8) For recent reviews, see: (a) Tilley, T. D. In The Chemistry of
Organo Silicon Compounds; Patai, S., Rappoport, Z., Eds.; Wiley: New
York, 1989; p 1415. (b) Schubert, U. In Progress in Organosilicon
Chemistry; Marciniec, B., Chojnowski, J ., Eds.; Gordon and Breach:
Switzerland, 1995; p 278. (c) Schubert, U. Angew. Chem., Int. Ed. Engl.
1994, 33, 419. (d) Corey, J . Y.; Braddock-Wilking, J . Chem. Rev. 1999,
99, 175.
(9) (a) Thorn, D. L.; Harlow, R. L. Inorg. Chem. 1990, 29, 2017. (b)
Tanaka, Y.; Yamashita, H.; Shimada, S.; Tanaka, M. Organometallics
1997, 16, 3246. (c) Shimada, S.; Tanaka, M.; Shiro, M. Angew. Chem.,
Int. Ed. Engl. 1996, 35, 1856. (d) Schubert, U.; Mu¨ller, C. J . Organomet.
Chem. 1989, 373, 165. (e) Hofmann, P.; Meier, C.; Hiller, W.; Heckel,
M.; Riede, J .; Schmidt, M. U. J . Organomet. Chem. 1995, 490, 51. (f)
LaPointe, A. M.; Rix, F. C.; Brookhart, M. J . Am. Chem. Soc. 1997,
119, 906.
(1) Part 61: Pfeiffer, J .; Kickelbick, G.; Schubert, U. Organometal-
lics, submitted for publication.
(2) Collman, J . P.; Hegedus, L. S.; Norton, J . R.; Finke, R. G.
Principles and Applications of Organotransition Metal Chemistry;
University Science Books: Mill Valley: CA, 1987; p 241.
(3) Ankersmit, H. A.; Løken, B. H.; Kooijman, H.; Spek, A. L.; Vrieze,
K.; van Koten, G. Inorg. Chim. Acta 1996, 252, 141.
(4) Phosphorus and halide trans.
(5) de Graaf, W.; Harder, S.; Boersma, J .; van Koten, G.; Kanters,
J . A. J . Organomet. Chem. 1988, 358, 545.
(6) Blacker, A. J .; Clarke, M. L.; Loft, M. S.; Mahon, M. F.; Williams,
J . M. J . Organometallics 1999, 18, 2867.
10.1021/om990665d CCC: $19.00 © 2000 American Chemical Society
Publication on Web 12/10/1999

Transition Metal Silyl Complexes
Organometallics, Vol. 19, No. 1, 2000 63
Sch em e 1. Syn th esis of th e Dim eth yl Com p lexes
1-5
F igu r e 1. Employed P,N-chelating ligands.
Recently, we reported that the platinum dimethyl
complex [(κ2-P,N)-Ph2PCH2CH2NMe2]PtMe2 (1), con-
taining a hemilabile P,N-chelating ligand, readily reacts
with trimethoxysilane, while the corresponding bis-
(phosphine) complex (dppe)PtMe2 (dppe ) Ph2PCH2CH2-
PPh2) is unreactive.10 The higher reactivity was attrib-
uted to the reversible decoordination of the weakly
bonded nitrogen atom that reversibly opens a coordina-
tion site at the metal. The cis methyl trimethoxysilyl
complex cis-[(κ2-P,N)-Me2NCH2CH2PPh2]-Pt[Si(OMe)3]-
Me,11 the bis(trimethoxysilyl) complex [(κ2-P,N)-Me2-
NCH2CH2PPh2]-Pt[Si(OMe)3]2, and methyltrimethoxy-
silane were identified among the products, but also large
portions of tetramethoxysilane. The formation of the
latter compounds suggests that the hemilabile ligand
promotes not only the oxidative addition of the silane
but also scrambling reactions of the silicon substituents,
possibly via silylene intermediates.
To have a broader range of starting compounds
available to exploit the potential emerging from this
observation and to investigate the influence of the ring
size and ring rigidity of the P,N-chelating ligand on the
reactivity of the complexes, we prepared other P,N-
chelated platinum dimethyl complexes. We report here
on their synthesis and structure and on their reactions
with iodotrimethylsilane and 1,2-bis(dimethylsilyl)ben-
zene. The following P,N-ligands were employed (Figure
1): (diphenylphosphinomethyl)dimethylamine (PC1N),
(2-diphenylphosphinoethyl)dimethylamine (PC2N), (3-
diphenylphosphinopropyl)dimethylamine (PC3N), 2-di-
phenylphosphino-N,N-dimethylaniline (PN), and (o-di-
phenylphosphinobenzyl)dimethylamine (PCN).
(diphenylphosphinomethyl)dimethylamine (PC1N) un-
der various reaction conditions and different (nbd)-
PtMe2/PC1N ratios, only the bis(phosphine) complex 5
was isolated (Scheme 1) and no P,N-chelated complex
was observed. The latter result is in contrast to reac-
tions of dppm (dppm ) Ph2PCH2PPh2) with complexes
of the type (η4-bisolefin)PtCl2 by which (dppm)PtCl2 is
obtained.14 The corresponding complex (PC1N)PtMe2 is
possibly too unstable because of the weak coordination
of the nitrogen; the weak Pt-N bond cannot compensate
the strain of a four-membered ring, and a second
phosphorus donor is coordinated.
1
The H NMR spectra (Table 1) of the complexes 1-4
showed two doublets with platinum satellites resulting
from the Pt-Me ligands and a singlet with platinum
satellites for the methyl substituents at nitrogen. The
3J PtNCH coupling of the latter resonances unambiguously
proved the coordination of the nitrogen atom to the
metal. The 13C{1H} NMR spectra of 1-4 showed the
resonances of the Pt-Me groups at about 14 ppm (CH3
trans to phosphorus) and about -20 ppm (cis to phos-
phorus) as doublets with platinum satellites. Their
stereochemical assignment was made on the basis of the
2
cis
different J PPtC coupling constants (2J PPtC ≈ 4-6 Hz,
2J PPtC
≈ 110 Hz).15 In contrast, the resonances of
trans
the chemically equivalent methyl ligands in the bis-
(phosphine) complex 5 appeared as a doublet of doublets
1
with platinum satellites both in the H and in the 13C-
{1H} NMR spectrum due to the cis and trans couplings
1
to the two phosphorus atoms. The J PtP coupling con-
stants extracted from the 31P{1H} NMR spectra of 1-5
were found to be in the typical range for platinum
complexes with phosphine ligands trans to a ligand with
a strong trans-influence.15
Resu lts a n d Discu ssion
Rea ction s of th e Com p lexes 1-4 w ith Iod otr i-
m eth ylsila n e. Reactions of diimine platinum dimethyl
complexes with various group IV trimethyl halides have
been reported to lead to the formation of octahedral
coordinated platinum(IV) complexes by trans addition
of the M-X bond.16,17 Contrary to that, when the
compounds 1-4 were reacted with iodotrimethylsilane,
no reaction occurred at room temperature. Only heating
to 60 °C resulted in the formation of new complexes
Syn th esis of P ,N-Ch ela ted P la tin u m Dim eth yl
Com p lexes. Reaction of (η4-2,5-norbornadiene)dimeth-
ylplatinum(II), (nbd)PtMe2,12 with PC2N, PC3N, PN, or
PCN in benzene at room temperature led to almost
quantitative formation of the chelated complexes 1-4.
They were isolated as crystalline compounds in 77-84%
yield.13 In contrast, when (nbd)PtMe2 was reacted with
(10) Pfeiffer, J .; Schubert, U. Organometallics 1999, 18, 3245.
(11) Cis with respect to phosphorus and silicon.
(12) (a) Drew, D.; Doyle, J . R. Inorg. Synth. 1972, 13, 48. (b) Clark,
H. C.; Manzer, L. E. J . Organomet. Chem. 1973, 59, 411.
(13) (nbd)PtMe2 was found to give better yields in the ligand
substitution reaction than the analogous 1,5-cyclooctadiene (COD)
complex. This is attributed to the smaller bite angle of nbd compared
to COD, enhancing the ease of the ligand displacement: Appleton, T.
G.; Hall, J . R.; Williams, M. A. J . Organomet. Chem. 1986, 303, 139,
and references cited therein.
(14) (a) Anderson, G. K.; Clark, H. C.; Davies, J . A. Inorg. Chem.
1981, 20, 3607. (b) Anderson, G. K.; Davies, J . A.; Schoeck, D. J . Inorg.
Chim. Acta 1983, 76, L251.
(15) Pregosin, P. S.; Kunz, R. W. In 31P and 13C NMR of Transition
Metal Phosphine Complexes; Diehl, P., Fluck, E., Kosfeld, R., Eds.;
NMR, Basic Principles and Progress, Vol. 16; Springer: Berlin and
Heidelberg, 1979.

64 Organometallics, Vol. 19, No. 1, 2000
Ta ble 1. Ch a r a cter istic 1H, 13C{1H}, a n d 31P {1H} NMR Da ta of Com p lexes 1-5a
Pfeiffer et al.
complex
δ (PtCH3)b
δ (N(CH3)2)c
δ (PtCH3)d
δ (N(CH3)2
δ (31P)e
1
1.21 (66.68, 7.73)f
1.48 (89.73, 7.33)g
0.14 (87.04, 8.63)
0.35 (64.29, 7.58)
1.27 (65.20, 7.52)f
1.53 (91.11, 7.41)g
0.21 (86.11, 8.18)g
0.37 (65.76, 7.45)f
1.18 (69.01, 6.23, 7.79)h
2.24 (18.01)
-24.69 (748.7, 4.2)
14.45 (709.8, 113.5)
-20.93 (745.5, 5.5)
14.83 (719.6, 113.5)
-24.04 (755.3, 4.3)
17.66 (718.4, 112.3)
-20.06 (748.3, 4.4)
13.49 (723.2, 112.3)
6.95 (617.3, 98.0, 8.2)h
49.19
35.93 (2071.5)
2
3
4
5
2.60 (18.78)
2.87 (17.44)
51.26
15.29 (2113.0)
34.79 (2128.9)
25.24 (2061.8)
9.59 (1837.2)
52.14
2.37 (18.90)
2.80 (19.26)
2.16
47.52, 52.85
48.10
a
b
3
C6D6 (1, 3, 5) or acetone-d6 (2); the spectra of 4 were recorded in acetone-d6 at 233 K. 2J PtCH and J PPtCH (Hz) in parentheses.
3J PtNCH (Hz) in parentheses. 1J PtC and J PPtC (Hz) in parentheses. 1J PtP (Hz) in parentheses. f trans-CH3 as determined by a gs-CH-
HMQC experiment. cis-CH3 as determined by a gs-CH-HMQC experiment. Cis- and trans-coupling constants to phosphorus.
c
d
2
e
g
h
Ta ble 2. Ch a r a cter istic 1H, 13C{1H}, a n d 31P {1H} NMR Da ta of th e Com p lexes 6-9 (CDCl3)a
complex
δ (PtCH3)b
δ (N(CH3)2)c
δ (PtCH3)d
δ (N(CH3)2
δ (31P)e
6
7
8
9
0.89 (75.69, 3.66)
0.58 (71.98, 5.30)
1.08 (75.57, 3.74)
0.79 (72.02, 4.88)
3.02 (n.o.)
2.98 (13.41)
3.52 (11.21)
2.66, 3.20
-26.44 (602.7, 5.5)
-21.52 (572.2, 6.0)
-25.74 (609.3, 5.0)
-21.02 (579.8, 4.5)
51.95
54.38
54.95
49.23, 56.12
29.24 (4642.3)
9.99 (4685.0)
19.90 (4616.7)
16.30 (4688.7)
a
b
3
c
d
2
298 K (6-8) and 253 K (9). 2J PtCH and J PPtCH (Hz) in parentheses. 3J PtNCH (Hz) in parentheses. 1J PtC and J PPtC (Hz) in
parentheses. 1J PtP (Hz) in parentheses.
e
2J PPtC coupling constants (≈5 Hz) typical for a trans
cis
Sch em e 2. Rea ction of th e P ,N-Ch ela ted
Com p lexes 1-4 w ith Iod otr im eth ylsila n e
N-Pt-C arrangement (Table 2). In addition, an X-ray
structure analysis of 9 unambiguously proved the
stereochemical arrangement of the ligands (vide infra).
The 31P{1H} NMR spectra were characterized by sig-
1
nificantly larger J PtP coupling constants (≈4600 Hz)
than in the starting compounds 1-4. Such large values
1
of J PtP are typical for platinum phosphine complexes
bearing ligands with a weak trans influence (e.g., halide,
alkoxide).15,20 The stereoselectivity of the methyl/iodide
exchange reaction which has already been observed in
the reaction of P,N-chelated palladium dimethyl com-
plexes with organic halides5 can be explained by the
different π-acceptor properties of the ligands, leading
to the trans arrangement of the strongest π-acceptor
ligand (phosphorus) with the π-donor ligand (iodide).
Rea ction of th e Com p lexes 1-4 w ith 1,2-Bis-
(d im et h ylsilyl)b en zen e. 1,2-bis(silyl)benzenes are
known for their pronounced tendency to form chelated
bis(silyl) complexes when reacted, for example, with η2-
alkene or dialkylmetal complexes, due to the ease of an
intramolecular oxidative addition reactions.9c,21 Reaction
of the dialkyl platinum(II) complexes 1, 3, and 4 with
1,2-bis(dimethylsilyl)benzene at 60 °C led to the bis-
(silyl)platinum(II) complexes 10-12 and methane (iden-
tified by GC) within 60 h. The complexes were isolated
by crystallization from 1:10 benzene/petroleum ether
(30/50) in very good yields (Scheme 3). They were quite
stable in the solid state under an atmosphere of argon,
but slowly decomposed in air. Surprisingly, complete
consumption of the dimethyl complexes could only be
achieved when 2 equiv of 1,2-bis(dimethylsilyl)benzene
along with tetramethylsilane within 12 h as monitored
by 1H and 31P{1H} NMR spectroscopy (3 h in the
reaction of 2). Platinum(IV) complexes were not ob-
served by NMR spectroscopy during the reaction, and
the trans iodo methyl complexes 6-9 were obtained in
very good yields as the only metal-containing products
after crystallization from petroleum ether (30/50)/
benzene (10:1) (Scheme 2).4 Puddephatt et al.18 have
described the formation of (bpy)Pt(I)Me (bpy ) 2,2′-
bipyridine) by heating (bpy)Pt(I)(SiMe3)Me2 (obtained
from (bpy)PtMe2 and Me3SiI19) to 177-192 °C. Accord-
ingly, the formation of the complexes 6-9 can be
rationalized by an oxidative addition of Me3Si-I fol-
lowed by a reductive elimination of tetramethylsilane.
The stereochemistry of the complexes 6-9 (iodide
trans to phosphorus) was confirmed by the low chemical
shift values of the Pt-Me ligands trans to nitrogen in
the 13C{1H} NMR spectra (≈ -23 ppm) and by the small
(20) (a) Grim, S.; Keiter, R. L. Inorg. Chem. 1967, 6, 1133. (b)
Heaton, B. T.; Pidcock, A. J . Organomet. Chem. 1968, 14, 235. (c) Clark,
H. C.; McBride, S. S.; Payne, N. C.; Wong, C. S. J . Organomet. Chem.
1979, 178, 393. (d) Osakada, K.; Kim, Y.-J .; Yamamoto, A. J . Orga-
nomet. Chem. 1990, 382, 303. (e) Bryndza, H. E.; Calabrese, J . C.;
Marsi, M.; Roe, D. C.; Tam, W.; Bercaw, J . E. J . Am. Chem. Soc. 1986,
108, 4805. (f) Andrews, M. A.; Gould, G. L. Organometallics 1991, 10,
387. (g) Schmidbaur, H.; Adlkofer, J . Chem. Ber. 1974, 107, 3680.
(21) (a) Shimada, S.; Rao, M. L. N.; Tanaka, M. Organometallics
1999, 18, 291. (b) Shimada, S.; Tanaka, M.; Honda, K. J . Am. Chem.
Soc. 1995, 117, 8289. (c) Eaborn, C.; Mutham, T. N.; Pidcock, A. J .
Organomet. Chem. 1973, 63, 107. (d) Tanaka, M.; Uchimura, Y. Bull.
Chim. Soc. Fr. 1992, 129, 667.
(16) (a) Kuyper, J . Inorg. Chem. 1977, 16, 2171. (b) Kuyper, J . Inorg.
Chem. 1978, 17, 4634. (c) Levy, C. J .; Puddephatt, R. J . J . Chem. Soc.,
Chem. Commun. 1995, 2115. (d) Levy, C. J .; Vittal, J . J .; Puddephatt,
R. J . Organometallics 1996, 15, 35. (e) Levy, C. J .; Puddephatt, R. J .
J . Am. Chem. Soc. 1997, 119, 10127. (f) Vittal, J . J .; Puddephatt, R. J .
Organometallics 1996, 15, 2108.
(17) Addition of Si-halogen bonds to Pt(0) complexes, e.g.: Ya-
mashita, H.; Tanaka, M.; Goto, M. Organometalllics 1997, 16, 4696.
(18) Levy, C. J .; Puddephatt, R. J . Organometallics 1995, 14, 5019.
(19) Levy, C. J .; Vittal, J . J .; Puddephatt, R. J . Organometallics
1994, 13, 1559.

Transition Metal Silyl Complexes
Organometallics, Vol. 19, No. 1, 2000 65
Ta ble 3. Ch a r a cter istic 1H, 13C{1H}, 29Si-INEP T, a n d 31P {1H} NMR Da ta of th e Com p lexes 10-12
(a ceton e-d 6)
complex
δ(SiCH3)a
δ(NCH3)b
δ(SiCH3)c
δ(NCH3)
δ(29Si)d
δ(31P)e
10
-0.08 (31.62)
0.42 (24.09, 2.81)
-0.04 (32.51)
0.46 (22.54, 2.85)
-0.46, 0.10,
2.98 (17.57)
4.77 (3.7)
5.15 (7.4)
4.30 (3.6)
4.99 (8.3)
4.87 (4.9)
5.78 (n.o.)
6.33 (8.7)
8.00 (4.9)
50.06
-0.81 (1424.3, 5.6)
29.49 (1501.8, 167.7)
-1.38 (1510.3, 3.6)
30.04 (1490.4, 164.0)
-2.39 (1452.4, 6.2)
28.09 (1507.5, 167.3)
57.07
(1392.8, 167.2)
51.37
(1481.9, 161.1)
38.52
(1439.8, 154.9)
11
3.41 (15.36)
54.12
12f
2.64 (18.43)
3.03 (20.07)
50.09
55.41
0.21, 0.53
a
4
b
c
d
2
3J PtSiCH and J PPtSiCH (Hz) in parentheses. 3J PtNCH (Hz) in parentheses. 3J PPtSiC (Hz) in parentheses. 1J PtSi and J PPtSi (Hz) in
parentheses. 1J PtP and J SiPtP (Hz) in parentheses. f 240 K.
e
2
Sch em e 3. Rea ction of Com p lexes 1-4 w ith
with HSi(OMe)3. In the reaction described here, inter-
mediate I was not detected. Unexpectedly, no intramo-
lecular addition seems to occur in the next step of the
reaction, but instead intermolecular oxidative addition
of a second molecule of 1,2-bis(dimethylsilyl)benzene,
followed by reductive C-Si elimination of 1-dimethyl-
silyl-2-trimethylsilylbenzene to give the hydrido(silyl)
complex II. This is in accordance with the formation of
complexes 10-12 and 1-dimethylsilyl-2-trimethylsilyl-
benzene in a 1:1 ratio. Subsequent intramolecular
reaction via intermediate III followed by elimination of
H2 yields the bis(silyl) complexes 10-12. Interestingly,
there is no scrambling of the substituents at the silicon
atoms as we have observed in the reaction of 1 with HSi-
(OMe)3.10 This is probably due to the incorporation of
both silicon atoms in a chelate ring.
1,2-Bis(d im eth ylsilyl)ben zen e
Formation of 13 is probably due to traces of oxygen
in the reacting system. However, another experiment
showed that 13 is probably not formed from the bis-
(silyl) complexes: By heating in air, 11 was quantita-
tively converted to the bis(silanolate) analogue (κ2-P,N)-
(PN)Pt[o-(OMe2Si)C6H4], but no 13 was formed.1
Possible explanations for the formation of 13 are the
insertion of oxygen into a platinum silicon bond in a
platinum(IV) intermediate and subsequent reductive
elimination of 13 or the catalytic oxidation of the
hydridosilane, followed by oxidative addition of the OH
and the SiH group, and elimination of 13.
was employed, and 1-dimethylsilyl-2-trimethylsilylben-
zene (δ29Si: -3.78, SiMe3; -20.43, SiHMe2) was formed
along with the bis(silyl) complexes in a 1:1 ratio. In
addition, traces of 4,5-benzo-2-oxa-1,3-disilacyclopent-
4-ene 13 was found (<5%, δ29Si: 14.93).
The 31P{1H} NMR spectra of the bis(silyl) complexes
showed the phosphorus signal accompanied by platinum
and trans silicon satellites (Table 3). Compared to the
1
iodide methyl complexes 6-9, the J PtP coupling con-
stants are much smaller, due to the strong trans
influence of the silyl ligand.15 The signals of the Si-
1
Compared to the complexes 1, 3, and 4, (PC3N)PtMe2
(2) exhibited a higher reactivity in the reaction with 1,2-
bis(dimethylsilyl)benzene: A vigorous reaction accom-
panied by a color change of the solution from pale yellow
to dark red readily occurred at room temperature.
Within 6 h, 2 was completely consumed (monitored by
1H and 31P{1H} NMR). Along with 1-dimethylsilyl-2-
trimethylsilylbenzene, four new platinum complexes
were formed (δ31P: 7.22, 1J PtP ) 3147.23 Hz; 19.39, 1J PtP
CH3 groups in the H NMR spectra of 10-12 showed
the coupling to phosphorus and were accompanied by
platinum satellites. The chemically different silicon
atoms gave resonances at significantly different chemi-
cal shifts in the 29Si NMR spectra (INEPT): Whereas
the resonance of the silicon atom trans to phosphorus,
2
trans
assigned by the typically large J PPtSi
coupling
constant (≈165 Hz), was found at about 30 ppm, the
silicon atom trans to nitrogen showed a chemical shift
) 2799.87 Hz; 23.08, 1J PtP ) 1649.50 Hz; 25.87, 1J PtP
)
of about -1 ppm (2J PPtSi ≈ 5 Hz). This lower chemical
cis
1462.07 Hz), but the identity of these compounds
remains unclear, because separation could not be
achieved.
shift of the silicon atom trans to nitrogen may be the
result of the stronger electron back-donation from
platinum to silicon due to the missing π-acceptor
properties of nitrogen and the weak Pt-N bond.
Dyn a m ic Beh a vior of th e Com p lexes 4, 9, a n d
12 in Solu tion . As already reported for (PCN)Pd(Me)-
[OCH(CF3)2], (PCN)Pd(Me)(OC6H5),22 and (PCN)RhCl-
(CO),23 the complexes 4, 9, and 12 containing the PCN
The necessity of 2 equiv 1,2-bis(dimethylsilyl)benzene
for complete consumption of the dimethyl complexes as
well as the formation of 1-dimethylsilyl-2-trimethylsi-
lylbenzene is in accordance with the reaction mecha-
nism depicted in Scheme 4, which has already been
postulated for the reaction of 1 with HSi(OMe)3.10
Oxidative addition of 1,2-bis(dimethylsilyl)benzene fol-
lowed by reductive elimination of methane is presumed
to lead to the formation of the methyl(silyl) complex I,
the analogue of which was observed in the reaction of 1
1
ligand showed only broad resonances in the H NMR
spectra for the methylene protons as well as for the
protons of N-methyl groups at room temperature,
(22) Kapteijn, G. M.; Spec, M. R. P.; Grove, D. M.; Kooijman, H.;
Spek. A. L.; van Koten, G. Organometallics 1996, 15, 1405.
(23) Rauchfuss, T. B.; Patino, F. T.; Roundhill, D. M. Inorg. Chem.
1975, 14, 652.

66 Organometallics, Vol. 19, No. 1, 2000
Pfeiffer et al.
Sch em e 4. Su ggested Mech a n ism for th e F or m a tion of th e Bis(silyl) Com p lexes 10-12a
a
It remains unclear whether the dimethyl amino group is coordinated to the metal in the platinum(IV) intermediates;
stereochemical drawing has been done arbitrarily.
PtMe2 compared to (dppe)PtMe2 in the reaction with
HSi(OMe)3.10 To confirm this observation for the reac-
tions described in this article, (dppe)PtMe2 was reacted
with iodotrimethylsilane and 1,2-bis(dimethylsilyl)ben-
zene, respectively, under the same conditions as the
P,N-substituted complexes. In the reaction with
Me3SiI, (dppe)Pt(Me)I and tetramethylsilane were
formed, but the reaction was much slower. After 12 h
(when 1-4 had completely reacted), only 30% conver-
sion was observed by 1H NMR, while complete reaction
required 48 h. By crystallization from 10:1 petroleum
ether (30/50)/benzene, (dppe)Pt(Me)I was isolated in
88% yield.25 When (dppe)PtMe2 was treated with 1,2-
bis(dimethylsilyl)benzene at 60 °C for 60 h, no reaction
was observed by 1H and 31P{1H} NMR spectroscopy.
These experiments clearly show the enhanced reactivity
of the P,N-chelated platinum dimethyl complexes com-
pared to (dppe)PtMe2 due to the weakly bonded nitrogen
ligand.
F igu r e 2. Conformational interconversion of the PCN
ligand in complexes 4, 9, and 12 in solution.
resulting from the flexibility of the PCN ligand (Figure
2). Above 323 K, these resonances formed two sharp
averaged signals, whereas below the coalescence tem-
peratures (4, 276 K; 9, 289 K; 12, 266 K) the diaste-
reotopic protons gave rise to separate resonances. From
these spectroscopic results, the activation enthalpies
∆Gq for the conformational interconversion have been
calculated to be 55 kJ /mol (4), 57 kJ /mol (9), and 51 kJ /
mol (12), respectively.24
Com p a r a tive Exp er im en ts w ith (d p p e)P tMe2.
We recently reported the enhanced reactivity of (PC2N)-
X-r a y Str u ctu r e An a lyses of 1, 9, a n d 11 (Figures
3-5, Tables 3 and 4). As expected, all complexes showed
an almost square planar coordination of the platinum
(24) Braun, S.; Kalinowski, H.-O.; Berger, S. 150 and More Basic
NMR Experiments; Wiley-VCH: Weinheim, 1998; p 136.

Transition Metal Silyl Complexes
Organometallics, Vol. 19, No. 1, 2000 67
224.3(1), Pt-N 221.0(7) pm;26 (P∩N)AuMe2 [P∩N ) 3,7-
dimethyl-1,5,7-triaza-3-phosphabicyclo[3.3.1]nonane]
Au-P 218.1(9), Au-N 222(1) pm27). This indicates that
the Pt-N bond is much weaker than the Pt-P bond.
The complexes 1 and 11 are of particular interest,
because they bear the same ligands trans to phosphorus
and nitrogen. The first interesting observation is that
the Pt-P bond in 11 is about 6 pm longer than in 1,
whereas the Pt-N bond in 11 is lengthened by 15 pm
(!) compared to 1. This lengthening causes the Pt-N
distance in 11 (similar in 9) to become longer than the
Pt-P distance. The Pt-N distance in 11 is, to the best
of our knowledge, the longest Pt-N bond distance in a
square planar platinum complex reported so far.28 The
bis(silyl) complex 11 may thus be considered a T-shaped
(three-coordinate) complex weakly stabilized by a ni-
trogen donor atom. This is in line with the previously
reported high tendency for redistribution reactions of
substituents at silicon, which are favored by an empty
coordination site at the metal.10,29
F igu r e 3. Molecular structure of 1.
In general, bond lengths trans to silyl ligands are
longer than trans to alkyl ligands owing to the π-ac-
ceptor property of the silyl ligands. On the other hand,
the π-donation of the iodide ligand in 9 results in a
shortening of the Pt-P bond (2.204(2) Å). With 2.6697-
(6) Å, the length of the Pt-I bond lies within the range
of known complexes with a trans P-Pt-I arrange-
ment.30 In both 1 and 11, the Pt-C or Pt-Si distance
trans to the weakly bonded nitrogen atom is signifi-
cantly longer than trans to the phosphorus atom. The
relative increase in length is 1.6% in the dimethyl
complex 1, but 3.0% in the bis(silyl) complex 11. This
clearly shows that the Pt-C(Si) bonds are increasingly
strengthened as the Pt-N interaction becomes weaker.
The weaker Pt-N interaction in 11 is possibly due to
the lower basicity of the aryl-bonded amino group. The
combination of the trans influence of the silyl ligand and
the lower basicity of the nitrogen atom results in the
large lengthening of the Pt-N distance in 11 compared
to 1.
F igu r e 4. Molecular structure of 9.
atom (sum of angles at Pt close to 360°). Deviations from
an orthogonal arrangement of cis ligands are mainly due
to the different “bite angles” of the employed P,N
ligands, which is the smallest for PN (in 11) and the
largest for PCN (in 9) and due to the steric strain
imposed by the phenyl substituents bound to phospho-
rus. The five-membered ring in 1 adopts a distorted
envelope conformation, with P, Pt, N, and C(4) being
almost coplanar. In 11, the dihedral angle between the
coordination plane of the platinum atom and the plane
Si(30), C(31), C(36), Si(37) is 166°, and 148.7° with the
plane formed by N(1), C(2), C(7), P(8), respectively. The
six-membered ring in 9 adopts a slightly distorted boat
conformation with Pt, N, C(14), and C(19) being almost
in one plane.
Con clu sion s
We have described the synthesis of some new plati-
num dimethyl complexes bearing P,N-chelating ligands
which show a much higher reactivity toward both
iodotrimethylsilane and 1,2-bis(dimethylsilyl)benzene
than (dppe)PtMe2. This is attributed to the hemilabile
P,N ligands which enable reversible opening of a
coordination site by decoordination of the amino group.31
(26) Thorn, D. L.; Calabrese, J . C. J . Organomet. Chem. 1988, 342,
269.
The most interesting structural feature is the dis-
tances between the platinum atom and the ligand
atoms, particularly the Pt-P and Pt-N distances (Table
5). Despite the different radii of the P and N atoms, the
Pt-N and Pt-P distances are of the same magnitude,
as already reported for other dimethyl transition metal
complexes containing phosphorus and nitrogen donor
atoms in a cis arrangement ((Ph3P)(py)PtMe2 Pt-P
(27) Assmann, B.; Angermann, K.; Paul, M.; Riede, J .; Schmidbaur,
H. Chem. Ber. 1995, 125, 891.
(28) Ling, E. C. H.; Allen, G. W.; Hambley, T. W. J . Chem. Soc.,
Dalton Trans. 1993, 3705. In some cases, longer Pt-N bond lengths
have been observed in pentacoordinated platinum(II) compounds,
e.g.: (a) Wernberg, O.; Hazell, A. J . Chem. Soc., Dalton Trans. 1980,
973. (b) De Renzi, A.; Di Blasio, B.; Saporito, A.; Scalone, M.; Vitagliano,
A. Inorg. Chem. 1980, 19, 960.
(29) (a) Mitchell, G. P.; Tilley, T. D. Angew. Chem., Int. Ed. Engl.
1998, 39, 2524. (b) McIndoe, J . S.; Nicholson, B. K. J . Organomet.
Chem. 1999, 577, 181.
(30) See, e.g.: (a) Lin, I. J . B.; Kao, L. T. C.; Wu, F. J .; Lee, G. H.;
Wang, Y. J . Organomet. Chem. 1986, 309, 225. (b) Engelter, C.; Moss,
J . R.; Nissimbeni, L. R.; Niven, M. L.; Reid, G.; Spiers, J . C. J .
Organomet. Chem. 1986, 315, 255. (c) Argazzi, R.; Bergamini, P.; Costa,
E.; Gee, V.; Hogg, J . K.; Martin, A.; Orpen, A. G.; Pringle, P. G.
Organometallics 1996, 15, 5591.
(25) Spectroscopic data: 31P{1H} NMR (C6D6): δ ) 45.29 (1J PtP
)
1706.5 Hz, cis-P), 45.85 (1J PtP ) 3978.3 Hz, trans-P).4 1H NMR (acetone-
d6): 0.78 (dd with Pt satellites, 3 H, 2J PtCH ) 59.20 Hz, 3J PPtCH ) 4.88,
7.36 Hz, CH3), 2.10-2.45 (m, 4 H, CH2CH2), 7.10-7.80 (m, 10 H, Ar-
H).

68 Organometallics, Vol. 19, No. 1, 2000
Pfeiffer et al.
Ta ble 4. Su m m a r y of Cr ysta l Da ta , Da ta Collection , a n d Str u ctu r e An a lysis of th e Com p lexes 1, 9, a n d 11
1
9
11
empirical formula
fw
temp [K]
C
18H26NPPt
C22H25INPPt‚2C6H6
C33H36NPPtSi2‚C3H6O
644.80
193(2)
482.46
213(2)
728.45
293(2)
cryst syst, space group
a [pm]
b [pm]
c [pm]
monoclinic, P2(1)/n
808.13(2)
1798.67(4)
1243.97(3)
90
91.50
90
1807.57(7)
4
1.773
7.845
triclinic, P1h
1000.40(2)
1035.56(1)
1465.47(3)
100.655(1)
107.717(1)
103.745(1)
1349.41(4)
2
monoclinic, C2/c
2897.92(4)
1117.26(1)
2233.75(3)
90
114.201(1)
90
6596.6(1)
8
R [deg]
â [deg]
γ [deg]
volume 106 [pm3]
Z
calcd density [g/cm3]
1.793
6.417
692
1.512
4.401
3008
abs coeff [mm-1
F(000)
]
936
cryst size [mm]
θ range for data
collection [deg]
0.24 × 0.22 × 0.015
0.24 × 0.08 × 0.06
0.56 × 0.40 × 0.30
1.99-23.26
1.52-20.81
1.96-20.86
no. of unique reflns/R(int) 2576/0.0573
2752/0.0190
97.5
2752/0/290
3456/0.0662
99.9
3456/0/353
completeness to θ [%]
no. of data/restraints/
params
99.8
2576/0/191
goodness-of-fit on F2
final R indices [I > 2σ(I)]
largest diff peak and
1.036
1.147
1.151
R1 ) 0.0341, wR2 ) 0.0859
1.307, -1.570
R1 ) 0.0274, wR2 ) 0.0670
0.746, -0.890
R1 ) 0.0291, wR2 ) 0.0778
0.961, -1.080
hole [Å-3
]
weighting scheme
w ) 1/[σ2(Fo2) + (0.0510P)2], P ) w ) 1/[σ2(Fo2) + (0.0274P)2 + 6.30P],P ) w ) 1/[σ2(Fo2) + (0.0404P)2 +
2 2 2
(Fo + 2Fc2)/3
(Fo + 2Fc2)/3
53.94P], P ) (Fo + 2Fc2)/3
recoordination of the nitrogen donor of the PC3N ligand,
thus enhancing the reactivity of 3 compared to 12. In
11, the weaker Pt-N interaction (due to the aromatic
amino group) compared to 1 may also be compensated
by the rigidity of the ligand.
By reaction of the dimethyl complexes 1, 3, and 4 with
1,2-bis(dimethylsilyl)benzene, the complexes 10-12
were obtained, which represent the first examples of
group 10 metal bis(silyl) complexes, bearing two differ-
ent supporting ligands (phosphorus and nitrogen) trans
to silicon. Further experiments with these unsym-
metrical substituted bis(silyl) complexes bearing two
electronically different Pt-Si bonds will provide further
insight into the factors governing the reactivity of
metal-silicon bonds.
F igu r e 5. Molecular structure of 11.
Exp er im en ta l Section
Ta ble 5. Im p or ta n t Bon d Len gth s (in p m ) a n d
An gles (d eg) in 1, 9, a n d 11
All operations were performed under argon in flame-dried
glassware. Solvents were dried (diethyl ether and tetrahydro-
furan over sodium, petroleum ether over sodium hydride,
chloroform and benzene over CaH2) and saturated with argon
before use.
Mass spectra were recorded on a Finnigan Voyager mass
spectrometer. NMR spectra were recorded on a Bruker AC 250
and a DRX 400 spectrometer (1H and 29Si NMR, TMS as
external standard; 31P NMR, 85% H3PO4 as external standard).
Detailed assignments of the NMR signals were made based
on CH-HMQC and SiH-HMBC experiments. 29Si NMR spectra
were recorded with an INEPT pulse sequence. The pulse
programs for the 2D experiments were taken from the Bruker
software library with the following parameters. 400/100 MHz
1
9
11
Pt-C/Si (trans P)
Pt-C/Si (trans N)
Pt-N
206.9(8)
203.7(9)
221.0(7)
224.3(2)
237.2(2)
230.4(2)
236.8(5)
230.3(2)
205.6(8)
223.3(6)
220.4(2)
266.97(6)
93.1(2)
88.9(2)
92.8(2)
85.7(2)
Pt-P
Pt-I
N-Pt-P
P-Pt-C/Si (cis)
N-Pt-X (cis)
C/Si-Pt-C/Si/I
84.6(1)
96.5(2)
92.0(2)
87.0(3)
79.1(1)
97.18(6)
101.2(1)
82.51(6)
In both types of reactions, (PC2N)PtMe2 (1), (PN)PtMe2
(3), and (PCN)PtMe2 (4) showed about the same reactiv-
ity, whereas (PC3N)PtMe2 (2) turned out to be much
more reactive. This may have two reasons: Six-
membered chelate rings are known to be less stable than
five-membered ones. In addition, the PC3N ligand
contains a highly flexible propylene spacer. Compared
to the PCN ligand with the more rigid aryl group (as
indicated by the slow conformational interconversion
shown by the variable-temperature NMR studies pre-
sented) this may result in a lower probability for the
(31) One referee has suggested an alternative explanation for the
enhanced reactivity of the P,N-chelated complexes compared to the
bis(phosphine) complexes on the basis of the electronic ground-state
properties. However, recent results indicate that reactions of late
transition metal diphosphine complexes often occur via predissociation
of a phosphine ligand rather than by an associative mechanism: (a)
Ozawa, F.; Hikida, T. Organometallics 1996, 15, 4501. (b) Romeo, R.;
Alibrandi, G. Inorg. Chem. 1997, 36, 4822. In addition, the difference
in the reactivity of complex 2 compared to 1, 3, and 4 can hardly be
explained based solely on electronic effects.

Transition Metal Silyl Complexes
Organometallics, Vol. 19, No. 1, 2000 69
gradient selected HMQC spectra:32 Relaxation delay D1 ) 2.0
[(κ2-P ,N)-3-(N,N-Dim eth yla m in o)p r op yld ip h en ylp h os-
p h in o]d im eth ylp la tin u m (II) (2): 1 mmol (0.317 g) of (nbd)-
PtMe2 and 1 mmol (0.271 g) of (3-diphenylphosphinopropyl)-
dimethylamine34 (PC3N); reaction time 1 h. Yield: 0.382 g (0.77
mmol, 77%), colorless powder. Anal. Calcd for C18H26NPPt
(496.49): C, 45.96; H, 5.68; N, 2.82; Found: C, 46.13; H, 5.58;
N, 2.77. 31P{1H} NMR (acetone-d6): δ ) 15.29 (s with Pt
1
s; evolution delay D2 ) 3.45 ms; 90° pulse, 12.5 µs for H, 10.0
µs for 13C hard pulses; 2K points in t2; spectral width 12 ppm
in F2 and 300 ppm in F1; 128 experiments in t1. 400/79.5 MHz
gradient-selected HMBC spectra:33 Relaxation delay D1 ) 2.0
s; evolution delay D2 ) 83.3 ms; delay for evolution of long-
range coupling D6 ) 83.3 ms (J ) 10 Hz); 2K points in t2;
spectral width 10 ppm in F2 and 300 ppm in F1; 128 experi-
ments in t1; zero-filling up to 1K.
1
satellites, J PtP ) 2113.04 Hz). 13C{1H} NMR (acetone-d6): δ
1
2
) -20.93 (d with Pt satellites, J PtC ) 745.5 Hz, J PPtC ) 5.5
1
X-r a y Str u ctu r e An a lyses of Com p lexes 1, 9, a n d 11
(Table 2). Selected crystals were mounted on a Siemens
SMART diffractometer with a CCD area detector by using
perfluorinated polyether (Riedel de Haen) as protecting agent.
Graphite-monochromated Mo KR radiation (71.073 pm) was
used for all measurements. The crystal-to-detector distance
was 4.40 cm. A hemisphere of data was collected by a
combination of three sets of exposures at the temperature
mentioned in the table. Each set had a different φ angle for
the crystal, and each exposure took 20 s and covered 0.3° in
ω. The data were corrected for polarization and Lorentz effects,
and an empirical absorption correction (SADABS) was applied.
The cell dimensions were refined with all unique reflections.
The structures were solved by direct methods (SHELXS86).
Refinement was carried out with the full-matrix least-squares
method based on F2 (SHELXL97) with anisotropic thermal
parameters for all non-hydrogen atoms. Hydrogen atoms were
inserted in calculated positions and refined riding with the
corresponding atom.
Gen er a l P r oced u r e for th e Syn th esis of th e Com -
p lexes 1-5. To a stirred solution of 1 mmol (0.317 g) of (η4-
2,5-norbornadiene)dimethylplatinum(II) in 3 mL of benzene
was added dropwise 1 mmol of the corresponding P,N ligand,
dissolved in 3 mL of benzene within 5 min. After complete
consumption of the starting compound 1 (monitored by 31P-
{1H} NMR spectroscopy), the solution was concentrated under
reduced pressure to about 1 mL and diluted with 10 mL of
petroleum ether (30/50). After storage of the reaction mixture
at -30 °C for 24 h to complete precipitation, the products were
filtered off, washed with two portions (5 mL each) of petroleum
ether (30/50), and dried under reduced pressure to yield the
complexes 1-5.
Hz, cis-PtCH3), 14.83 (d with Pt satellites, J PtC ) 719.6 Hz,
2J PPtC ) 113.53 Hz, trans-PtCH3), 23.58 (d, J PCC ) 6.5 Hz,
2
CH2), 27.56 (d, 1J PC ) 24.0 Hz, PCH2), 51.26 (s, N(CH3)2), 67.31
(d, J PCCC ) 6.5 Hz, NCH2), 129.60 (d, J PC ) 8.7 Hz, Ar-Ct),
3
131.05 (d, J PC ) 1.6 Hz, Ar-C4), 135.02 (d, J PC ) 11.4 Hz,
4
Ar-Ct), 136.03 (d, J PC ) 40.9 Hz, Ar-C1). H NMR (acetone-
1
1
2
3
d6): δ ) 0.14 (d with Pt satellites, J PtCH ) 87.04 Hz, J PPtCH
) 8.63, 3 H, cis-PtCH3), 0.35 (d with Pt satellites, J PtCH
2
)
3
64.29 Hz, J PPtCH ) 7.58, 3 H, trans-PtCH3), 1.80-2.00 (m, 2
H, CH2), 2.30-2.50 (m, 2 H, PCH2), 2.60 (s with Pt satellites,
3J PtNCH ) 18.78 Hz, 6 H, N(CH3)2), 2.80-3.00 (m, 2 H, NCH2),
7.30-7.50 (m, 6 H, Ar-H), 7.60-7.80 (m, 4 H, Ar-H). MS
(EI): m/z ) 481 (M+ - CH3, 18), 466 (M+ - 2CH3, 100), 421
(M+ - C6H5, 7).
[(κ2-P ,N)-2-(N,N-Dim eth yla m in o)p h en yld ip h en ylp h os-
p h in o]d im eth ylp la tin u m (II) (3): 1 mmol (0.317 g) of (nbd)-
PtMe2 and 1 mmol (0.305 g) of 2-diphenylphosphino-N,N-
dimethylaniline36 (PN); reaction time 2 h. Yield: 0.44 g (0.83
mmol, 83%); colorless powder. Anal. Calcd for C22H26NPPt
(530.51): C, 49.81; H, 4.94; N, 2.64. Found: C, 49.99; H, 4.76;
N, 2.61. 31P{1H} NMR (C6D6): δ ) 34.79 (s with Pt satellites,
1J PtP ) 2128.9 Hz). 13C{1H} NMR (C6D6): δ ) - 24.04 (d with
1
2
Pt satellites, J PtC ) 755.3 Hz, J PPtC ) 4.3 Hz, cis-PtCH3),
1
2
17.66 (d with Pt satellites, J PtC ) 718.4 Hz, J PPtC ) 112.3
Hz, 1 C, trans-PtCH3), 52.14 (s, N(CH3)2), 122.20 (d, J PC ) 9.7
Hz, Ar-Ct), 128.63 (d, J PC ) 9.7 Hz, Ph-Ct), 129.89 (d, J PC
)
2.3 Hz, Ph-C4), 131.75 (d, J PC ) 1.9 Hz, Ar-Ct), 133.54 (d with
Pt satellites, J PC ) 12.6 Hz, J PtC ) 19.66 Hz, Ph-Ct), 134.04
(d, J PC ) 42.1 Hz, Ph-C1), 134.55 (d, J PC ) 0.9 Hz, Ar-Ct),
1
135.07 (d, 1J PC ) 40.2 Hz, Ar-C1), 163.19 (s, Ar-C2), one signal
hidden by C6D6. 1H NMR (C6D6): δ ) 1.27 (d with Pt satellites,
2J PtCH ) 65.2 Hz, J PPtCH ) 7.52 Hz, 3 H, trans-PtCH3), 1.53
3
[(κ2-P ,N)-2-(N,N-Dim et h yla m in o)et h yld ip h en ylp h os-
p h in o]d im eth ylp la tin u m (II) (1): 1 mmol (0.317 g) of (nbd)-
PtMe2 and 1 mmol (0.257 g) of (2-diphenylphosphinoethyl)-
dimethylamine34 (PC2N); reaction time 3 h. Yield: 0.4 g (0.84
mmol, 84%), pale yellow powder. Anal. Calcd for C18H26NPPt
(482.46): C, 44.81; H, 5.43; N, 2.90. Found: C, 45.03, H, 5.35,
N, 2.81. 31P{1H} NMR (C6D6): δ ) 35.93 (s with Pt satellites,
1J PtP ) 2071.5 Hz). 13C{1H} NMR (C6D6): δ ) -24.69 (d with
2
3
(d with Pt satellites, J PtCH ) 91.11 Hz, J PPtCH ) 7.41 Hz, 3
3
H, cis-PtCH3), 2.87 (s with Pt satellites, J PtNCH ) 17.44 Hz, 6
3
H, N(CH3)2), 6.70-7.10 (m, 9 H, Ar-H), 7.34 (t, J HH ) 7.20
Hz, 1 H, Ar-H), 7.60-7.80 (m, 4 H, Ar-H). MS (EI): m/z )
515 (M+ - CH3, 38), 500 (M+ - 2CH3, 100), 453 (M+ - C6H5,
5), 423 (M+ - C6H5 - 2CH3, 5), 376 (M+ - 2C6H5, 12), 346
(M+ - 2C6H5 - 2CH3, 15).
[(κ2-P ,N)-2-(N,N-Dim eth ylam in om eth yl)ph en yldiph en yl-
p h osp h in o]d im eth ylp la tin u m (II) (4): 1 mmol (0.317 g) of
(nbd)PtMe2 and 1 mmol (0.319 g) of (2-diphenylphosphinoben-
zyl)dimethylamine23 (PCN); reaction time 2 h. Yield: 0.45 g
1
2
Pt satellites, J PtC ) 748.7 Hz, J PPtC ) 4.2 Hz, cis-PtCH3),
1
2
14.45 (d with Pt satellites, J PtC ) 709.8 Hz, J PPtC ) 113.5
1
Hz, trans-PtCH3), 29.56 (d, J PC ) 25.8 Hz, PCH2), 49.19 (s,
2
N(CH3)2), 64.44 (d, J PCC ) 9.5 Hz, NCH2), 128.62 (d, J PC
)
(0.81 mmol, 81%); colorless powder. Anal. Calcd for C23H28
-
9.5 Hz, Ar-Ct), 130.00 (s, Ar-C4), 133.41 (d, J PC ) 12.1 Hz,
Ar-Ct), Ar-C1 not observed.35 1H NMR (C6D6): δ ) 1.21 (d
with Pt satellites, 2J PtCH ) 66.68 Hz, 3J PPtCH ) 7.73, 3 H, trans-
NPPt (544.54): C, 50.73; H, 5.12; N, 2.57. Found: C, 50.92;
H, 5.19; N, 2.39. 31P{1H} NMR (C6D6): δ ) 25.24 (s with Pt
1
satellites, J PtP ) 2061.8 Hz). 13C{1H} NMR (C6D6, 298 K): δ
PtCH3), 1.48 (d with Pt satellites, 2J PtCH ) 89.73 Hz, 3J PPtCH
)
1
2
) -19.56 (d with Pt satellites, J PtC ) 745.9 Hz, J PPtC ) 4.6
7.33, 3 H, cis-PtCH3), 1.60-1.90 (m, 4 H, CH2CH2), 2.24 (s with
Pt satellites, 3J PtNCH ) 18.01 Hz, 6 H, N(CH3)2), 6.90-7.10 (m,
6 H, Ar-H), 7.60-7.80 (m, 4 H, Ar-H). MS (EI): m/z ) 482
(M+, 1), 467 (M+ - CH3, 38), 452 (M+ - 2CH3, 100), 422 (M+
- 4CH3, 45), 405 (M+ - C6H5, 3), 345 (M+ - C6H5 - 4CH3),
10), 328 (M+ - 2C6H5, 5). Crystals suitable for an X-ray
structure analysis were obtained from a saturated 5:1 hexane/
benzene (v/v) solution at 0 °C.
1
Hz, cis-PtCH3), 13.61 (d with Pt satellites, J PtC ) 728.7 Hz,
2J PPtC ) 112.6 Hz, trans-PtCH3), 49.44 (br, N(CH3)2), 68.88 (d,
3J PC ) 12.1 Hz, CH2), 129.43 (s, Ar-C4), 129.79 (d, J PC ) 35.3
Hz, Ph-Ct), 131.44 (d, J PC ) 41.6 Hz, Ar-Cq), 132.64 (d, J PC
)
4.7 Hz, Ph-C4), 133.87 (d, J PC ) 33.3 Hz, Ar-Cq),35 134.85 (d,
J PC ) 12.1 Hz, Ph-Ct), 139.99 (d, J PC ) 17.4 Hz, Ar-Ct), two
carbon signals hidden by C6D6. 13C{1H} NMR (acetone-d6, 233
1
2
K): δ ) -20.06 (d with Pt satellites, J PtC ) 748.3 Hz, J PPtC
) 4.4 Hz, cis-PtCH3), 13.49 (d with Pt satellites, 1J PtC ) 723.2
(32) Willker, W.; Leibfritz, D.; Kerssebaum, R.; Bernel, W. Magn.
Reson. Chem. 1993, 31, 287.
2
Hz, J PPtC ) 112.3 Hz, trans-PtCH3), 47.52 (s, NCH3), 52.85
(33) Hurd, R. E. J . Magn. Reson. 1990, 87, 422.
(34) Malet, R.; Morena-Man˜as, M.; Parella, T.; Pleixats, R. J . Org.
Chem. 1996, 61, 758.
(36) (a) Gilman, H.; Banner, I. J . Am. Chem. Soc. 1940, 62, 344. (b)
Fritz, H. P.; Gordon, I. R.; Schwarzhans, K. E.; Venzani, L. M. J . Chem
Soc. (A) 1965, 5210.
(35) Ar-Ct: tertiary aromatic carbon atom. Ar-Cq: quarternary
aromatic carbon atom.

70 Organometallics, Vol. 19, No. 1, 2000
Pfeiffer et al.
(s, NCH3), 69.22 (d, 3J PC ) 12.0 Hz, CH2), 129.78 (d, J PC ) 9.8
(EI): m/z ) 594 (M+, 10), 579 (M+ - CH3, 40), 467 (M+ - I,
30), 58 (H2CdN(CH3)2+, 100).
n
Hz, Ph-Ct), 130.49 (d, J PC ) 9.3 Hz, Ph-Ct), 131.21 (d, J PC
) 4.9 Hz, Ar-Ct), 131.75 (s, Ar-C4), 133.67 (s, Ph-C4), 134.64
(d, J PC ) 7.6 Hz, Ar-Ct), 135.59 (d, J PC ) 10.9 Hz, Ph-Ct),
136.20 (d, J PC ) 12.5 Hz, Ph-Ct), 141.43 (d, J PC ) 12.5 Hz,
Ar-Ct), 163.97 (d, J PC ) 28.9 Hz, Ar-C1), some quarternary
carbon atoms could not be assigned due to overlap of the
signals. 1H NMR (C6D6, 298 K): δ ) 1.14 (d with Pt satellites,
tr a n s-[(κ2-P ,N)-3-(N,N-Dim eth ylam in o)pr opyldiph en yl-
p h osp h in o](iod o)m et h ylp la t in u m (II) (7). Yield: 0.269 g
(0.39 mmol, 78%). Anal. Calcd for C18H25INPPt (608.36): C,
35.54; H, 4.14; N, 2.30. Found: C, 35.54; H, 4.28; N, 2.18. 31P-
1
{1H} NMR (CDCl3): δ ) 9.99 (s with Pt satellites, J PtP
)
4685.1 Hz). 13C{1H} NMR (CDCl3): δ ) -21.52 (d with Pt
3
2J PtCH ) 87.49 Hz, J PPtCH ) 8.14 Hz, 3 H, cis-PtCH3), 1.22 (d
2
3
satellites, J PtCH ) 572.2 Hz, J PPtCH ) 6.0 Hz, PtCH3), 22.27
2
3
1
with Pt satellites, J PtCH ) 73.41 Hz, J PPtCH ) 7.41 Hz, 3 H,
trans-PtCH3), 2.35 (b, 6 H, N(CH3)2), 3.00-3.80 (b, 2 H, CH2)
6.60-6.80 (m, 1 H, Ar-H), 6.90-7.10 (m, 9 H, Ar-H), 7.50-
(s with Pt satellites, J PtC ) 25.6 Hz, CH2), 26.39 (d, J PC
)
2
34.9 Hz, PCH2), 54.37 (s, N(CH3)2), 65.97 (d, J PCC ) 6.0 Hz,
NCH2), 129.55 (d, J PC ) 10.9, Ph-Ct), 131.02 (d, J PC ) 60.5
1
1
Hz, Ph-C1), 131.86 (s, 2 C, Ph-C4), 134.45 (d, J PC ) 10.9 Hz,
7.90 (m, 4 H, Ar-H). H NMR (acetone-d6, 233 K): δ ) 0.21
2
3
Ph-Ct). 1H NMR (CDCl3): δ ) 0.58 (d with Pt satellites, 2J PtCH
(d with Pt satellites, J PtCH ) 86.11 Hz, J PPtCH ) 8.18 Hz, 3
H, PtCH3), 0.37 (d with Pt satellites, 2J PtCH ) 65.76 Hz, 3J PPtCH
3
) 71.98 Hz, J PPtCH ) 5.30 Hz, 3 H, PtCH3), 1.75-1.95 (m, 2
3
) 7.45 Hz, 3 H, PtCH3), 2.37 (s with Pt satellites, J PtNCH
)
H, -CH2-), 2.20-2.50 (m, 2 H, PCH2), 2.65-2.80 (m, 2 H,
18.90 Hz, 3 H, NCH3), 2.80 (s with Pt satellites, 3J PtNCH ) 19.26
3
NCH2), 2.98 (s with Pt satellites, J PtNCH ) 13.41 Hz, 6 H,
2
n
Hz, 3 H, NCH3), 3.69 (dd, J HH ) 11.99 Hz, J HH ) 4.36 Hz, 1
H, NCH(H)), 4.08 (dd, J HH ) 11.99 Hz, 1 H, NCH(H)), 6.70-
N(CH3)2), 7.30-7.50 (m, 6 H, Ar-H), 7.60-7.80 (m, 4 H, Ar-
H). MS (EI): m/z ) 608 (M+, 4), 593 (M+ - CH3, 12), 481 (M+
- I, 7), 58 (H2CdN(CH3)2+, 100).
2
6.80 (m, 1 H, Ar-H), 7.15-7.30 (m, 2 H, Ar-H), 7.40-7.70
(m, 11 H, Ar-H). MS (EI): m/z ) 544 (M+, 1), 529 (M+ - CH3,
12), 514 (M+ - 2CH3, 100), 470 (M+ - 2CH3 - N(CH3)2, 10),
467 (M+ - C6H5, 2), 390 (M+ - 2C6H5, 20).
tr a n s-[(κ2-P ,N)-2-(N,N-Dim eth ylam in o)ph en yldiph en yl-
p h osp h in o](iod o)m et h ylp la t in u m (II) (8). Yield: 0.272 g
(0.43 mmol, 86%). Anal. Calcd for C21H23INPPt (642.38): C,
39.27; H, 3.61; N, 2.18. Found: C, 39.26: H, 3.75; N, 2.15. 31P-
Bis[(N,N-d im eth yla m in o)m eth yld ip h en ylp h osp h in o]-
d im eth ylp la tin u m (II) (5): 0.642 mmol (0.204 g) of (nbd)-
PtMe2 and 0.642 mmol (0.214 g) of diphenylphosphinometh-
yldimethylamine37 (PC1N); reaction time 1 h. Yield: 0.18 g
(0.253 mmol, 78.9% relative to (nbd)PtMe2); pale yellow
powder. Anal. Calcd for C32H42N2P2Pt (711.73): C, 54.00; H,
5.95; N, 3.94. Found: C, 53.79; H, 5.81; N, 3.76. 31P{1H} NMR
1
{1H} NMR (CDCl3): δ ) 19.90 (s with Pt satellites, J PtP
)
4616.7 Hz). 13C{1H} NMR (CDCl3): δ ) -25.74 (d with Pt
2
3
satellites, J PtCH ) 609.3 Hz, J PPtCH ) 5.0 Hz, 1 C, PtCH3),
54.95 (s, 2 C, N(CH3)2), 123.51 (d, J PC ) 9.8 Hz, 1 C, Ar-Ct),
129.55 (d, J PC ) 11.4 Hz, 4 C, Ph-Ct), 129.91 (d, J PC ) 73.0
1
Hz, 2 C, Ph-C1), 131.99 (d, 4J PC ) 2.7 Hz, 2 C, Ph-C4), 134.08
(d, J PC ) 12.0 Hz, 4 C, Ph-Ct), 161.16 (d, J PC ) 15.3 Hz, 1 C
Ar-C2), some of the aromatic carbon atoms could not be
assigned unambiguously due to overlap of the signals. 1H NMR
1
(C6D6): δ ) 9.59 (s with Pt satellites, J PtP ) 1837.2 Hz). 13C-
{1H} NMR (C6D6): δ ) 6.95 (dd with Pt satellites, 1J PtC ) 617.3
2
2
Hz, J PPtC(trans) ) 98.0 Hz, J PPtC(cis) ) 8.2 Hz, Pt(CH3)2), 48.10
1
2
2
(s, N(CH3)2), 58.37 (d with Pt satellites, J PC ) 41.0 Hz, J PtPC
(CDCl3): δ ) 1.08 (d with Pt satellites, J PtCH ) 75.57 Hz,
) 17.1 Hz, NCH2P), 127.8, 129.4 (Ar-Ct), 134.4 (s, Ar-C4),
3J PPtCH ) 3.74 Hz, 3 H, PtCH3), 3.53 (s with Pt satellites,
3J PtNCH ) 11.21 Hz, 6 H, N(CH3)2), 7.25-7.75 (m, 14 H, Ar-
H). MS (EI): m/z ) 642 (M+, 10), 627 (M+ - CH3, 100), 515
(M+ - I, 20).
1
2
135.88 (d with Pt satellites, J PC ) 42.1 Hz, J PtPC ) 14.8 Hz,
Ar-C1). 1H NMR (C6D6): δ ) 1.18 (dd with Pt satellites, 2J PtCH
) 69.01 Hz, 3J PPtCH ) 6.23, 7.79 Hz, 6 H, Pt(CH3)2), 2.16 (s, 12
3
tr a n s-[(κ2-P ,N)-2-(N,N-Dim eth yla m in om eth yl)p h en yl-
d ip h en ylp h osp h in o](iod o)m eth ylp la tin u m (II) (9). Yield:
0.269 g (0.41 mmol, 82%). Anal. Calcd C22H25INPPt (656.41):
C, 40.26; H, 3.84; N, 2.38. Found: C, 40.01; H, 3.87; N, 2.12.
H, N(CH3)2), 3.04 (s with Pt satellites, J PtPCH ) 12.35 Hz, 4
H, NCH2P), 7.00-7.18 (m, 12 H, Ar-H), 7.70-7.90 (m, 8 H,
Ar-H). MS (EI): m/z ) 515 (M+ - CH3, 38), 500 (M+ - 2CH3,
100), 453 (M+ - C6H5, 5), 423 (M+ - C6H5 - 2CH3, 5), 376
(M+ - 2C6H5, 12), 346 (M+ - 2C6H5 - 2CH3, 15).
31P{1H} NMR (CDCl3): δ ) 16.30 (s with Pt satellites, 1J PtP
)
4688.7 Hz). 13C{1H} NMR (CDCl3, 298 K): δ ) -21.23 (d with
Pt satellites, 2J PtCH ) 582.8 Hz, 3J PPtCH ) 5.3 Hz, PtCH3), 67.99
Rea ction s of th e Com p lexes 1-4 w ith Iod otr im eth yl-
sila n e. A 0.5 mmol sample of the corresponding platinum
dimethyl complex was dissolved in 3 mL of benzene, and 0.5
mmol (0.1 g) iodotrimethylsilane was added. After stirring for
12 h at 60 °C (3 h in the case of 2), the reaction mixture was
poured into 30 mL of petroleum ether (30/50). The reaction
mixture was stored for 24 h at -30 °C to complete precipita-
tion. The product was filtered off, washed with two portions
of 5 mL of petroleum ether (30 /50) each, and dried under
reduced pressure to give complexes 6-9 as pale yellow, air-
stable powders.
(d, J PC ) 2.1 Hz, CH2), 127.91 (d, J PC ) 61.6 Hz, Ph-C1),
3
1
129.30 (d, J PC ) 54.5 Hz, Ar-C1), 129.33 (d, J PC ) 11.4 Hz,
1
Ph-Ct), 130.25 (d, J PC ) 7.6 Hz, Ar-Ct), 131.73 (d, J PC ) 2.2
4
Hz, Ph-C4), 131.99 (br, Ar-Ct), 133.17 (d, J PC ) 3.8 Hz, Ar-
Ct), 133.53 (d, J PC ) 9.3 Hz, Ar-Ct), 135.07 (d, J PC ) 11.4 Hz,
Ph-Ct), 140.12 (d, J PC ) 14.2 Hz, Ar-C2), the N(CH3)2 carbon
atoms were not observed at 298 K due to the conformational
flexibility of the complex. 13C{1H} NMR (CDCl3, 253 K): δ )
2
3
-21.02 (d with Pt satellites, J PtCH ) 579.8 Hz, J PPtCH ) 4.5
Hz, PtCH3), 49.23 (s, NCH3), 56.12 (s, NCH3), 67.69 (d, 3J PC
)
tr a n s-[(κ2-P ,N)-2-(N,N-Dim eth yla m in o)eth yld ip h en yl-
p h osp h in o]iod om eth ylp la tin u m (II) (6). Yield: 0.269 g
(0.39 mmol, 78%). Anal. Calcd for C17H23INPPt (594.33): C,
9.3 Hz, CH2), 126.46 (d, J PC ) 69.8 Hz, Ph-C1), 126.72 (d,
1
1J PC ) 55.0 Hz, Ph-C1) 127.85 (d, J PC ) 55.0 Hz, Ar-C1),
1
128.83 (d, J PC ) 10.9 Hz, Ph-Ct), 129.39 (d, J PC ) 7.6 Hz, Ar-
34.36; H, 3.90; N, 2.36. Found: C, 34.10; H, 3.84; N, 2.24. 31P-
Ct), 130.74 (d, J PC ) 1.2 Hz, Ph-C4), 130.96 (d, J PC ) 1.2
4
4
1
{1H} NMR (CDCl3): δ ) 29.24 (s with Pt satellites, J PtP
)
Hz, Ph-C4), 131.62 (br, Ar-C4), 132.21 (d, J PC ) 4.4 Hz, Ar-
4642.33 Hz). 13C{1H} NMR (CDCl3): δ ) -26.44 (d with Pt
Ct), 132.68 (d, J PC ) 8.7 Hz, Ar-Ct), 133.65 (d, J PC ) 10.9 Hz,
2
3
satellites, J PtCH ) 602.7 Hz, J PPtCH ) 5.5 Hz, PtCH3), 31.38
2
Ph-Ct), 134.41 (d, J PC ) 12.0 Hz, Ph-Ct), 138.90 (d, J PC
)
1
(d, J PC ) 35.4 Hz, 1 C, PCH2), 51.95 (s, N(CH3)2), 61.95 (d,
13.6 Hz, Ar-C2). 1H NMR (CDCl3, 298 K): δ ) 0.82 (d with
Pt satellites, 2J PtCH ) 73.24 Hz, 3J PPtCH ) 4.89 Hz, 3 H, PtCH3),
2.50-4.00 (br, 8 H, CH2 + N(CH3)2), 6.91 (t, J HH ) 9.26 Hz, 1
H, Ar-H), 7.27 (m, 1 H, Ar-H), 7.40-7.80 (m, 12 H, Ar-H).
2J PCC ) 2.2 Hz, NCH2), 129.00 (d, J PC ) 58.3, Ph-C1), 129.86
1
(d, J PC ) 10.9 Hz, Ph-Ct), 132.44 (d, J PC ) 2.7 Hz, Ph-C4),
134.28 (d, J PC ) 11.5 Hz, Ph-Ct). H NMR (CDCl3): δ ) 0.89
1
2
3
(d with Pt satellites, J PtCH ) 75.69 Hz, J PPtCH ) 3.66 Hz, 3
H, PtCH3), 2.30-2.80 (m, 4 H, CH2CH2), 3.02 (s, 6 H, N(CH3)2),
7.40-7.60 (m, 6 H, Ar-H), 7.70-7.90 (m, 4 H, Ar-H). MS
1H NMR (CDCl3, 253 K): δ ) 0.79 (d with Pt satellites, J PtCH
2
) 72.02 Hz, 3J PPtCH ) 4.88 Hz, 3 H, PtCH3), 2.66 (s, 3 H, NCH3),
2
3.20 (s, 3 H, NCH3), 3.43 (d, J HH ) 12.21 Hz, 1 H, CH(H)),
2
4.04 (d, J HH ) 12.20 Hz, 1 H, CH(H)), 6.88 (t, J HH ) 8.31 Hz,
(37) (a) Bohme, H.; Hartke, K. Chem. Ber. 1960, 93, 1305. (b) Aguiar,
A. M.; Hansen, K. C.; Mague, J . T. J . Chem. Soc. (A) 1967, 2883.
1 H, Ar-H), 7.20-7.80 (m, 13 H, Ar-H). MS (EI): m/z ) 656

Transition Metal Silyl Complexes
Organometallics, Vol. 19, No. 1, 2000 71
(M+, 8), 641 (M+ - CH3, 60), 529 (M+ - I, 30), 58 (H2Cd
N(CH3)2+, 100). Crystals suitable for an X-ray structure
analysis were obtained by slow evaporation of the solvent from
a concentrated benzene solution at room temperature. The
crystals contained two benzene molecules in the asymmetric
unit.
F igu r e 6. Atom labeling of the platinum complex 11.
135.30 (s, Ar-C9), 152.80 (s, SiCAr), 157.60 (s, SiCAr), 160.05
Rea ction of th e Com p lexes 1-4 w ith 1,2-Bis(d im eth yl-
silyl)ben zen e. To a solution of 0.5 mmol of the corresponding
dimethylplatinum(II) complex in 2 mL of benzene was added
dropwise 1.0 mmol (0.196 g) of 1,2-bis(dimethylsilyl)benzene.
After stirring the reaction mixture for 60 h at 60 °C, the
solution was cooled to room temperature and transferred into
20 mL of petroleum ether (30/50) via a syringe. After storage
at -30 °C for 24 h to complete precipitation, the products were
filtered off, washed with three portions of 2 mL of petroleum
ether each, and dried under reduced pressure, yielding pale
yellow powders.
2
1
(d, J PC ) 21.1 Hz, Ar-C2). H NMR (acetone-d6): δ ) -0.04
3
(s with Pt satellites, J PtSiCH ) 32.51 Hz, 6 H, cis-Si(CH3)2),
3
4
0.46 (d with Pt satellites, J PtSiCH ) 22.54 Hz, J PPtSiCH ) 2.85
3
Hz, 6 H, trans-Si(CH3)2), 3.41 (s with Pt satellites, J PtNCH
)
15.36 Hz, 6 H, N(CH3)2), 7.12 (t, J HH ) 7.04 Hz, 1 H, Ar-H11),
7.17 (t, J HH ) 7.04, 1 H, Ar-H10), 7.32 (d, J HH ) 6.91, 1 H,
Ar-H12), 7.36 (t, J HH ) 7.55 Hz, 1 H, Ar-H4), 7.45-7.58 (m,
8 H, Ar-H), 7.64 (t J HH ) 7.68, 1 H, Ar-H5), 7.75-7.85 (m, 4
H, Ar-H), 7.90 (dd, J ) 4.35, 8.19 Hz, 1 H, Ar-H6). Crystals
suitable for an X-ray structure analysis were obtained by slow
cooling of saturated acetone solution to 0 °C. The crystals
contained one acetone molecule in the asymmetric unit (see
Figure 6).
[(κ2-P ,N)-2-(N,N-Dim et h yla m in o)et h yld ip h en ylp h os-
p h in o][1,2-bis(d im eth ylsilyl)ben zen e]p la tin u m (II) (10).
Yield: 0.235 g (0.365 mmol, 73%). Anal. Calcd for C26H36
-
NPPtSi2 (644.80): C, 48.43; H, 5.63; N, 2.17. Found: C, 48.17;
H, 5.28; N, 2.09. 31P{1H} NMR (acetone-d6): δ ) 57.07 (s with
[(κ2-P ,N)-2-(N,N-Dim eth yla m in om eth yl)p h en yld ip h en -
ylp h osp h in o][1,2-b is(d im et h ylsilyl)b en zen e]p la t in u m -
(II) (12). Yield: 0.272 g (0.385 mmol, 77%). Anal. Calcd for
1
2
Pt satellites, J PtP ) 1392.8 Hz, J SiPtP ) 167.2 Hz). 29Si NMR
1
(acetone-d6): -0.81 (d with Pt satellites, J PtSi ) 1424.3 Hz,
2J PPtSi ) 5.6 Hz, cis-Si), 29.49 (d with Pt satellites, J PtSi
)
1
C
31H38NPPtSi2 (706.87): C, 52.67; H, 5.42; N, 1.98. Found: C,
1501.8 Hz, 2J PPtSi ) 167.7 Hz, trans-Si). 13C{1H} NMR (acetone-
52.24; H, 5.35; N, 1.88. 31P{1H} NMR (acetone-d6): δ ) 38.52
d6): δ ) 4.77 (d, 3J PPtSiC ) 3.7 Hz, cis-Si(CH3)2), 5.15 (d, 3J PPtSiC
(s with Pt satellites, 1J PtP ) 1439.8 Hz, 2J SiPtP
) 154.9 Hz).
trans
1
) 7.4 Hz, trans-Si(CH3)2), 33.56 (d, J PC ) 21.2 Hz, PCH2),
29Si NMR (acetone-d6, 233 K): -2.39 (d with Pt satellites, 1J PtSi
2
50.06 (s, N(CH3)2), 62.73 (d, J PCC ) 9.2 Hz, NCH2), 126.91 (s,
2
) 1452.4 Hz, J PtPSi ) 6.2 Hz, cis-Si(CH3)2), 28.09 (d with Pt
Ar-C5), 127.10 (s, Ar-C4), 128.00 (d, 1J PC ) 23.9 Hz, Ph-C1),
1
2
satellites, J PtSi ) 1507.5 Hz, J PtPSi ) 167.3 Hz, trans-Si-
128.88 (d, J PC ) 10.1 Hz, Ph-Ct), 130.24 (s, Ar-C6), 130.19
(CH3)2). 13C{1H} NMR (acetone-d6, 240 K): δ ) 4.87 (d, 3J PPtSiC
(d, J PC ) 1.8 Hz, Ph-C4), 131.08 (s, Ar-C3), 134.15 (d, J PC
)
4
3
) 4.9 Hz, SiCH3), 5.78 (s, SiCH3), 6.33 (d, J PPtSiC ) 8.7 Hz,
11.9 Hz, Ph-Ct), 158.13 (d, J PC ) 4.6 Hz, Ar-Cq), 158.30 (d,
3
SiCH3), 8.00 (d, J PPtSiC ) 4.9 Hz, SiCH3), 50.09 (s, NCH3),
J PC ) 6.4 Hz, Ar-Cq). 1H NMR (acetone-d6): δ ) -0.08 (s with
3
55.41 (s, NCH3), 68.10 (d, J PCCC ) 10.9 Hz, NCH2), 127.50-
3
Pt satellites, J PtSiCH ) 31.62 Hz, 6 H, cis-Si(CH3)2), 0.42 (d
134.00 (Ar-C), 134.75 (d, J PC ) 8.5 Hz, Ar-C), 137.20 (d, J PC
) 14.7 Hz, Ar-C), 140.45 (d, J PC ) 17.4 Hz, Ar-C), 158.01 (d,
3
4
with Pt satellites, J PtSiCH ) 24.09 Hz, J PPtSiCH ) 2.81 Hz, 6
H, trans-Si(CH3)2), 2.50-2.70 (m, 4 H, CH2CH2), 2.98 (s with
3
3J PPtSiC ) 4.4 Hz, Si-CAr), 160.82 (d, J PPtSiC ) 6.0 Hz, Si-
Pt satellites, 3J PtNCH ) 17.57 Hz, 6 H, N(CH3)2), 7.08 (t, J HH
)
CAr). 1H NMR (acetone-d6, 240 K): δ ) -0.46 (s with Pt
7.03 Hz, 1 H, Ar-H5), 7.14 (t, J HH ) 7.03 Hz, 1 H, Ar-H4),
7.29 (d, J HH ) 7.03 Hz, 1 H, Ar-H6), 7.50-7.65 (m, 7 H, Ph-H
+ Ar-H3), 7.75-7.90 (m, 4 H, Ar-H).
3
satellites, J PtSiCH ) 26.22 Hz, 3 H, SiCH3), 0.10 (s with Pt
3
satellites, J PtSiCH ) 30.72 Hz, 3 H, SiCH3), 0.21 (s with Pt
satellites, 3J PtSiCH ) 26.22 Hz, 3 H, SiCH3), 0.53 (s, 3 H, SiCH3),
[(κ2-P ,N)-2-(N,N-Dim eth yla m in o)p h en yld ip h en ylp h os-
p h in o][1,2-bis(d im eth ylsilyl)ben zen e]p la tin u m (II) (11).
Yield: 0.291 g (0.42 mmol, 84% with respect to 3). Anal. Calcd
for C30H36NPPtSi2‚C3H6O (750.93): C, 52.78; H, 5.64; N, 1.87.
Found: C, 52.64; H, 5.66; N, 1.81. 31P{1H} NMR (acetone-d6):
2.64 (s with Pt satellites, 3J PtNCH ) 18.43 Hz, 3 H, NCH3), 3.03
3
(s with Pt satellites, J PtSiCH ) 20.07 Hz, 3 H, NCH3), 3.55 (d,
2
2J HH ) 12.29 Hz, 1 H, CH(H)), 3.91 (d, J HH ) 12.29 Hz, 1 H,
CH(H)), 7.00-7.90 (m, 18 H, Ar-H).
1
δ ) 51.37 (s with Pt and Si satellites, J PtP ) 1481.9 Hz,
2J SiPtP
) 161.1 Hz). 29Si NMR (acetone-d6): -1.38 (d with
trans
Ack n ow led gm en t. Financial support by the Fonds
zur Fo¨rderung der wissenschaftlichen Forschung (FWF),
Austria, is gratefully acknowledged. We also thank
Wacker-Chemie GmbH for gifts of chemicals.
Pt satellites, 1J PtSi ) 1510.3 Hz, 2J PPtSi ) 3.6 Hz, cis-Si), 30.04
1
2
(d with Pt satellites, J PtSi ) 1490.4 Hz, J PPtSi ) 164.0 Hz,
trans-Si). 13C{1H} NMR (acetone-d6): δ ) 4.30 (d, J PPtSiC
)
3
3.6 Hz, cis-Si(CH3)2), 4.99 (d, 3J PPtSiC ) 8.3 Hz, trans-Si(CH3)2),
54.12 (s, N(CH3)2), 121.67 (d, J PC ) 8.3 Hz, Ar-C6), 127.10 (s,
Su p p or tin g In for m a tion Ava ila ble: NMR spectra of
complexes 1-12 (PDF) and X-ray diffraction data for 1, 9, and
11 (CIF). This material is available free of charge via the
Internet at http://www.pubs.acs.org.
Ar-C11), 127.30 (s, Ar-C10), 127.99 (d, J PC ) 23.9 Hz, Ph-
1
C1), 128.40 (d, J PC ) 10.1 Hz, Ar-C4), 128.95 (d, J PC ) 9.2 Hz,
Ph-Ct), 130.20 (s, Ar-C12), 130.81 (s, Ph-C4), 131.29 (d, J PC
) 24.8 Hz, Ar-C1), 133.06 (d, J PC ) 9.2 Hz, Ar-C5), 133.53
(d, J PC ) 11.0 Hz, Ar-C3), 134.45 (d, J PC ) 14.7 Hz, Ph-Ct),
OM990665D