On the reactivity of platina-β-diketones - Synthesis and characterization of acylplatinum(II) complexes

Article abstract of DOI:10.1002/(SICI)1521-3749(200003)626:3<661::AID-ZAAC661>3.0.CO;2-4

The platina-β-diketones [Pt₂{(COR)₂H}₂(μ-Cl)₂] (1, R = Me a, Et b) react with phosphines L in a molar ratio of 1:4 through cleavage of acetaldehyde to give acylplatinum(II) complexes trans-[Pt(COR)Cl(L)₂] (2) (R/L = Me/P(p-FC₆H₄)₃ a, Me/P(p-CH₂=CHC₆H₄)Ph₂ b, Me/P(n-Bu)₃ c, Et/P(p-MeOC₆H₄)₃ d). 1a reacts with Ph₂As(CH₂)₂PPh₂ (dadpe) in a molar ratio of 1:2 through cleavage of acetaldehyde yielding [Pt(COMe)Cl(dadpe)] (3a) (configuration index: SP-4-4) and [Pt(COMe)Cl(dadpe)] (configuration index: SP-4-2) (3b) in a ratio of about 9:1. All acyl complexes were characterized by ¹H, ¹³C and ³¹P NMR spectroscopy. The molecular structures of 2a and 3a were determined by single-crystal X-ray diffraction. The geometries at the platinum centers are close to square planar. In both complexes the plane of the acyl ligand is nearly perpendicular to the plane of the complex (88(2)° 2a, 81.2(5)° 3a).

Full text of DOI:10.1002/(SICI)1521-3749(200003)626:3<661::AID-ZAAC661>3.0.CO;2-4

On the Reactivity of Platina-b-diketones ± Synthesis and Characterization of
Acylplatinum(II) Complexes
Dirk Steinborn*, Tobias Hoffmann, Michael Gerisch, Clemens Bruhn, Harry Schmidt, and Karsten Nordhoff
Halle, Institut fuÈr Anorganische Chemie der Martin-Luther-UniverisitaÈt
Julian A. Davies, Kristin Kirschbaum, and Ingo Jolk
Toledo, Ohio/USA, Department of Chemistry of the University
Received November 16th, 1999.
Dedicated to Professor Karl-Heinz Thiele on the Occasion of his 70th Birthday
Abstract. The platina-b-diketones [Pt2{(COR)2H}2(l-Cl)2] (1,
R = Me a, Et b) react with phosphines L in a molar ratio of 1 : 4
through cleavage of acetaldehyde to give acylplatinum(II) com-
plexes trans-[Pt(COR)Cl(L)2] (2) (R/L = Me/P(p-FC6H4)3 a,
Me/P(p-CH2=CHC6H4)Ph2 b, Me/P(n-Bu)3 c, Et/P(p-
MeOC6H4)3 d). 1 a reacts with Ph2As(CH2)2PPh2 (dadpe) in a
molar ratio of 1 : 2 through cleavage of acetaldehyde yielding
[Pt(COMe)Cl(dadpe)] (3 a) (configuration index: SP-4-4) and
[Pt(COMe)Cl(dadpe)] (configuration index: SP-4-2) (3 b) in a
ratio of about 9 : 1. All acyl complexes were characterized by 1H,
13C and 31P NMR spectroscopy. The molecular structures of 2 a
and 3 a were determined by single-crystal X-ray diffraction. The
geometries at the platinum centers are close to square planar. In
both complexes the plane of the acyl ligand is nearly perpendi-
cular to the plane of the complex (88(2)° 2 a, 81.2(5)° 3 a).
Keywords: Platina-b-diketones; Platinum(II) complexes;
Crystal structure.
Zur Reaktivitat von Platina-b-diketonen ± Synthese und Reaktvitat von
È
È
Acylplatin(II)-Komplexen
InhaltsuÈbersicht. Die Platina-b-diketone [Pt2{(COR)2H}2 ´
(l-Cl)2] (1, R = Me a, Et b) reagieren mit Phosphinen L im
molaren VerhaÈltnis 1 : 4 unter Abspaltung von Acetaldehyd
zu Acylplatin(II)-Komplexen trans-[Pt(COR)Cl(L)2] (2)
(R/L = Me/P(p-FC6H4)3 a, Me/P(p-CH2=CHC6H4)Ph2 b,
Me/P(n-Bu)3 c, Et/P(p-MeOC6H4)3 d). 1 a setzt sich im
MolverhaÈltnis 1 : 2 mit Ph2As(CH2)2PPh2 (dadpe) unter Ab-
spaltung von Acetaldehyd zu [Pt(COMe)Cl(dadpe)] (3 a)
(Konfigurationsindex: SP-4-4) und [Pt(COMe)Cl(dadpe)]
(Konfigurationsindex: SP-4-2) (3 b) im VerhaÈltnis von unge-
faÈhr 9 : 1 um. Alle Acylkomplexe sind durch 1H-, 13C- and
31P-NMR-Spektroskopie charakterisiert worden. Die Mole-
kuÈlstrukturen von 2 a und 3 a sind durch RoÈntgeneinkristall-
struturanalyse ermittelt worden. Sie weisen eine ungefaÈhr
quadratisch-planare Anordnung der zentralen Platinatome
auf. In beiden Komplexen steht die Ebene des Acylliganden
nahezu senkrecht auf der Komplexebene (88(2)° 2 a, 81.2(5)°
3 a).
Introduction
With bidentate nitrogen donor ligands (2,2'-bipyridine
and 1,10-phenanthroline derivatives), an intramolecular
oxidative addition takes place yielding acyl(hydrido)pla-
tinum(IV) complexes that undergo reductive elimination
of aldehyde at higher temperatures (Scheme 1, a) [5, 6].
With triphenylphosphine and 1,2-bis(diphenylphosphi-
no)ethane (dppe), aldehyde is cleaved with formation of
acylplatinum(II) complexes (Scheme 1, b) [7].
Reactions of trimethylsilylacetylenes with hexachloro-
platinic acid in butanol afford platina-b-diketones
[Pt2{(COR)2H}2(l-Cl)2] (1) in high yields [1, 2]. These
16-valence-electron complexes with kinetically labile li-
gands exhibit reactivity that is in marked contrast to that
of Lukehart's metalla-b-diketones [LxM{(COR)2H}]
(M = Mo, W, Mn, Re, . . .; L = CO, Cp, . . .) which are
both electronically saturated (18 valence electrons) and
kinetically inert [3]. The reactivity of complexes 1 can be
understood as that of intramolecular-hydrogen-bond-sta-
bilized acyl(hydroxycarbene)platinum(II) complexes [4].
* Prof. Dr. Dirk Steinborn,
Institut fuÈr Anorganische Chemie,
Martin-Luther-UniversitaÈt Halle-Wittenberg,
Kurt-Mothes-Str. 2, D-06120 Halle
E-mail: steinborn@chemie.uni-halle.de
Scheme 1
Z. Anorg. Allg. Chem. 2000, 626, 661±666
Ó WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2000
0044±2313/00/626661±666 $ 17.50+.50/0
661

D. Steinborn et al.
Table 1 Selected NMR data (chemical shifts in ppm, cou-
pling constants in Hz) for trans-[Pt(COR)Cl(L)2] complexes
2 a±2 d.
Here we report the reaction of platina-b-diketones
1 with substituted triarylphosphines, with tri(n-butyl)-
phosphine as a representative alkylphosphine, as well
as with the unsymmetrical bidentate ligand 1-(diphe-
nylarsino)-2-(diphenylphosphino)ethane (dadpe).
R/L
d(CO) d(31P)
[Dd(31P)]a)
1J(Pt, C) 2J(P, C) 1J(Pt, P)
Me/P(p-FC6H4)3 (2 a)
217.9 18.6
[27]
922
5.0
5.8
6.8
3499
3501
3075
3449
3480
3505
Results and Discussion
b)
Me/P(p-CH2=CHC6H4)Ph2 216.1 20.8
(2 b)
Me/P(n-Bu)3 (2 c)
[27]
8.2
Synthesis
b)
215.8
[41]
219.8 17.9
[28]
218.4 20.9
[26]
218.8 21.1
[26]
In methylene chloride at room temperature, platina-b-
diketones 1 react with phosphines in a molar ratio of
1 : 4 through cleavage of aldehyde to give acyl(chloro)-
platinum(II) complexes 2 (Scheme 2, a). By addition
of diethyl ether, complexes 2 a and 2 d are formed as
colorless (2 a) or pale-yellow crystals (2 d) in high
yields (2 a 82%, 2 d 84%). 2 a and 2 d are air stable
and freely soluble in methylene chloride and chloro-
form but insoluble in diethyl ether and hydrocarbons.
Complexes 2 b and 2 c were identified in solution only.
Et/P(p-MeOC6H4)3 (2 d)
ca 950 6.0
6
c)
Me/PPh3
c)
Et/PPh3
917
6
a)
Dd(31P) = d(31P)coord ± d(31P)non-coord. Data d(31P)non-coord are own mea-
surements or are taken from lit. [17].
b)
Not observed due to poor S/N ratio.
For comparison; values taken from lit. [7].
c)
spectra are at 1636 (2 a) and 1649 cm±1 (2 d) and the
Pt±Cl stretching vibrations are at 265 (2 a) and
260 cm±1 (2 d).
The diastereomeric structures of complexes 3 a and
3 b with their trans-P±Pt±Cl (3 a, configuration index:
SP-4-4) and trans-P±Pt±COMe (3 b, configuration in-
dex: SP-4-2) arrangement, respectively, were estab-
lished by the high and low value, respectively, of
1J(Pt, P) (3 a, 4454 Hz; 3 b, 1720 Hz), reflecting the
large difference in trans influences (Cl < COMe) [10].
The phosphorus resonances were found at 32.2 ppm
(3 a) and 43.7 ppm (3 b). In both cases the signals are
shifted to low field in comparison with the phosphorus
resonance of the free dadpe ligand (d = ±12.5), as ex-
pected when five-membered rings are formed [8]. The
1H and 13C NMR spectra of 3 a fully support the iden-
tity of the complex. The 13C resonance of the acetyl
carbon atom COMe is slightly shifted to high field
compared to that in the analogous dppe complex [7]
[Pt(COMe)Cl(dppe)] (231.5 vs. 244.3 ppm).
Scheme 2
The platina-b-diketone 1 a reacts with 1-(diphenyl-
arsino)-2-(diphenylphosphino)ethane (dadpe) in a mo-
lar ratio of 1 : 2 according to Scheme 2 (b) through
cleavage of acetaldehyde yielding the stereoisomeric
acyl(chloro)platinum(II) complexes 3 a and 3 b in a ra-
tio of about 9 : 1 (31P NMR). By standing 12 hours, the
major isomer 3 a precipitates as pale-yellow crystals in
78% yield. 3 a is slightly air-sensitive (decomposition
within 3±5 days in air) and freely soluble in acetone
but insoluble in diethyl ether and hydrocarbons.
Molecular structures
Spectroscopic characterization
The molecular structures of 2 a and 3 a determined by
single-crystal X-ray diffraction are shown in Figures 1
and 2. Selected bond lengths and angles are listed in
Tables 2 and 3. The unit cells contain discrete mole-
cules without any unusually short intermolecular con-
tacts.
The identities of the acyl(chloro)platinum(II) com-
plexes were confirmed by NMR spectroscopy (Ta-
ble 1). The trans configuration of the complexes 2 fol-
lows from the triplet pattern of the carbonyl carbon
atom resonance and the singlet pattern of the phos-
phorus signal in the 13C and 31P NMR spectra, respec-
tively. The coordination-induced shift of the phos-
phorus signal (d(31P)coord±d(31P)non-coord) is between
26 and 41 ppm to lower field. These values and the
The molecular structure of complex 2 a reveals
close to square-planar configuration with angles be-
tween 88.6(2) and 91.8(5)° at the platinum atom (sum
of the angles: 360.6°; greatest deviation of the mean
1
Ê
magnitudes of the J(Pt, P) coupling constants (3075±
square plane for C(37) by 0.11(2) A). The plane of the
3501 Hz) are as expected [8]. As for other acylplati-
num complexes trans-[Pt(COR)Cl(L)2] (L = phos-
phine) [9], the C±O stretching vibrations in the IR
acyl ligand is nearly perpendicular (88(2)°) to the
plane of the complex, to minimize steric interactions
with the bulky phosphine ligands.
662
Z. Anorg. Allg. Chem. 2000, 626, 661±666

On the Reactivity of Platina-û-diketones ± Synthesis and Characterization of Acylplatinum(II) Complexes
Ê
Table 3 Selected bond lengths (in A) and bond angles (in
°) for [Pt(COMe)Cl(dadpe)] 3 a.
Pt±C(27)
Pt±P
Pt±As
2.031(9)
2.219(2)
2.4628(8)
2.366(2)
1.20(1)
As±Pt±P
As±Pt±Cl
As±Pt±C(27)
P±Pt±C(27)
P±Pt±Cl
85.7(1)
96.5(1)
176.6(3)
91.0(3)
177.7(1)
86.8(3)
Pt±Cl
C(27)±O
P±C(26)
As±C(25)
1.834(8)
1.965(9)
Cl±Pt±C(27)
Pt±C(27)±C(28) 115.7(6)
Pt±C(27)±O
C(28)±C(27)±O
123.8(8)
120.2(9)
The coordination at the platinum center in complex
3 a is close to square planar (angles at Pt: 85.7(1)±
96.5(1)°; sum of angles: 360.0°; greatest deviation of
the mean square plane for the Pt atom by
Ê
0.0118(3) A). The ªbiteº angle of the dadpe ligand
(P±Pt±As 85.7(1)°) is in the range of those in other
dadpe complexes (79.1(1)±88.09(6)°; mean value:
83.1°; n = 9, n ± number of datapoints [11]). The che-
late ring exhibits a slightly distorted half-chair confor-
Fig. 1 ORTEP-III plot [18] of trans-[Pt(COMe)Cl{P(p-
FC6H4)3}2] (2 a), showing atom numbering (displacement el-
lipsoids at 30% probability); H atoms omitted for clarity.
Ê
mation with C(25) and C(26) beneath (±0.29(1) A)
Ê
and above (+0.47(1) A), respectively, the Pt±P±As
plane. The plane of the acyl ligand is nearly perpendi-
cular to the plane of the complex (81.2(5)°).
In both complexes, the magnitudes of the Pt±C
Ê
bond lengths (2.03(2)/2.031(9) A) as well as the C±O
Ê
bond lengths (1.22(2)/1.20(1) A) are in the range of
those found in other acylplatinum(II) complexes [9 b,
Ê
12]. The Pt±Cl bond in 2 a (2.436(4) A) is longer than
Ê
those in 3 a (2.366(2) A) and in the corresponding
Ê
dppe complex [Pt(COMe)Cl(dppe)] (2.368(3) A) [7]
reflecting the difference in trans influence of acetyl
and phosphine donors. As expected from the trans in-
fluences (phosphine > Cl), the Pt±P bonds in 2 a are
Ê
longer (2.304(4)/2.305(4) A) than those in 3 a
Ê
Ê
(2.219(2) A) and in [Pt(COMe)Cl(dppe)] (2.223(3) A,
P trans to Cl) [7].
Quantum Chemical Calculations
To help decide whether the reactions shown in
Scheme 2 (a) yielding the trans isomers 2 are thermo-
dynamically or kinetically controlled, DFT calcula-
tions were carried out for model complexes cis/trans-
[Pt(COMe)Cl(PR3)2] (R = H 4 a/b, Me 5 a/b, Ph 6 a/b).
In all cases the trans isomers are more stable than the
cis isomers by 1.9 (4), 8.3 (8.1) (5) and 15.8 (13.4) (6)
kcal mol±1.1) The dihedral angles P±Pt±C±O are for
the PH3 complexes 10.6/168.1° (4 a) and 153.5°2) (4 b)
as well as for the PMe3 complexes 50.3/117.4° (5 a)
and 105.1°2) (5 b). This is showing that, in complexes
with the more bulky PMe3 ligands, the acetyl ligands
Fig. 2 ORTEP-III plot [18] of [Pt(COMe)Cl(dadpe)] (3 a),
showing atom numbering (displacement ellipsoids at 30%
probability).
Ê
Table 2 Selected bond lengths (in A) and bond angles (in
°) for trans-[Pt(COMe)Cl{P(p-FC6H4)3}2] (2 a).
Pt±C(37)
Pt±Cl
2.03(2)
2.436(4)
2.305(4)
2.304(4)
1.48(3)
1.22(2)
1.80(2)±1.87(2)
1.34(2)±1.36(2)
P(1)±Pt±P(2)
P(1)±Pt±C(37)
P(1)±Pt±Cl
P(2)±Pt±C(37)
P(2)±Pt±Cl
173.1(2)
91.8(5)
88.7(1)
91.5(5)
88.6(2)
175.0(5)
Pt±P(1)
Pt±P(2)
C(37)±C(38)
C(37)±O
P±C
Cl±Pt±C(37)
1)
Values are given for B3LYP level and in parantheses for
Pt±C(37)±C(38) 118(1)
Pt±C(37)±O 118(1)
C(38)±C(37)±O 124(2)
C±P±C 102.9(8)±107.9(8)
C±F
BP86 level.
2)
Only the value for the phosphorus cis to the acetyl ligand
is given.
Z. Anorg. Allg. Chem. 2000, 626, 661±666
663

D. Steinborn et al.
do not lie in the plane of the complex. This is in
agreement with the solid-state structures of trans-
[Pt(COMe)Cl{P(p-FC6H4)3}2] (2 a) and [Pt(COMe) ´
Cl(dadpe)] (3 a) where the dihedral angles are P(1/2)±
Pt±C(37)±O 91(2)/95(2)° and P±Pt±C(27)±O 85.7(9)°,
respectively.
Experimental
All reactions were performed under an Ar atmosphere using
standard Schlenk techniques. The solvents were dried and
distilled prior to use. Infrared spectra were recorded on a
Galaxy Mattson 5000 FT-IR spectrometer using CsBr pellets.
NMR spectra were obtained on Varian Gemini 200, VXR
400, and Unity 500 spectrometers. Chemical shifts are rela-
tive to CHDCl2 (d 5.32), CD2Cl2 (d 53.8), CHCl3 (d 7.24) and
CDCl3 (d 77.0) as internal references; d(31P) is relative to ex-
ternal H3PO4 (85%). Complexes [Pt2{(COR)2H}2(l-Cl)2] (1)
were prepared according to literature methods [1]. Other
chemicals were commercial materials used without further
purification or after distillation.
Due to differences in the trans influences
(Cl < PR3 < COMe), the Pt±C bonds in trans com-
Ê
plexes are shorter (4 b: 2.024, 5 b: 2.010 A) than those
Ê
in cis complexes (4 a: 2.035, 5 a: 2.040 A) and the
Pt±Cl bonds are longer in trans complexes (4 b: 2.545,
Ê
Ê
5 b: 2.570 A) than those in cis complexes (4 a: 2.439,
5 a: 2.475 A). There are no noticable differences in
Ê
Synthesis of trans-[Pt(COMe)Cl{P(p-FC6H4)3}2] (2 a)
To [Pt2{(COMe)2H}2(l-Cl)2] (1) (75.8 mg, 0.12 mmol) in
methylene chloride (3 ml) P(p-FC6H4)3 (151 mg, 0.48 mmol)
was added. After 15 min diethyl ether (10 ml) was added to
the pale-yellow solution. After standing 12 hours crystals
formed were filtered off and dried in vacuo.
Yield: 178 mg (82%). M. p. 250±252 °C (dec.).
C38H27ClF6OP2Pt (906.12). C 50.46 (calc. 50.37); H 3.00
(3.00)%.
C±O bond lengths (1.253±1.255 A).
Discussion
As the quantum chemical calculations (see above)
and experimental observations [13] show, reactions ac-
cording to Scheme 2 (a) result in the formation of the
thermodynamically more stable trans isomers 2. Tak-
ing into account the higher trans influence of the
phosphorus donor site than the arsenic donor site in
the unsymmetrical chelate ligand dadpe, the major
isomer 3 a should be thermodynamically favoured
over the minor isomer 3 b (Scheme 2, b).
1H NMR (400 MHz, CDCl3): d = 1.24 (s, 3 H, CH3), 7.12 (`t', 12 H, Ph),
7.77 (m, 12 H, Ph). 13C NMR (100 MHz, CDCl3): d = 44.4 (t+d(br),
3J(P, C) = 6.2 Hz, 2J(Pt, C) = 121 Hz, CH3), 115.9 (d`t', 2J(F, C) = 21.5 Hz,
N = 3+5J(P, C) = 11.8 Hz, Cm), 125.4 (d`t', 4J(F, C) = 3.0 Hz, N =
1+3J(P, C) = 59 Hz, Ci), 136.9 (`q', N = 2+4J(P, C) = 22.6 Hz, Co), 164.5 (d,
1J(F, C) = 255 Hz, Cp), 217.9 (t+d, 2J(P, C) = 5.0 Hz, 1J(Pt, C) = 922 Hz,
CO). 31P NMR (81 MHz, CDCl3): d = 18.6 (s+d, 1J(Pt, P) = 3499 Hz). IR:
m = 1636 (s, CO), 265 (w, PtCl) cm±1
.
Synthesis of trans-[Pt(COEt)Cl{P(p-MeOC6H4)3}2] (2 d)
To [Pt2{(COEt)2H}2(l-Cl)2] (1) (94.0 mg, 0.14 mmol) in
methylene chloride (3 ml) P(p-MeOC6H4)3 (196.8 mg,
0.56 mmol) was added. Work-up was as described above.
Yield: 133 mg (84%). M. p. 187±189 °C (dec.).
C45H47ClO7P2Pt (992.37). C 53.51 (calc. 54.47); H 4.65
(4.77), Cl 3.65 (3.65)%.
Scheme 3
We showed [7] that the donor (L/L') induced clea-
vage of aldehyde proceeds most probably via the reac-
tion sequence i) formation of a mononuclear platina-
b-diketone complex A by Pt±Cl±Pt bridge cleavage, ii)
oxidative addition yielding an hydridoplatinum(IV)
complex B followed by iii) reductive elimination of al-
dehyde and formation of an acyl(chloro)platinum(II)
complex C (Scheme 3). Thus, reactions with monoden-
tate phosphines L/L' should proceed via the (unseen)
intermediate B. The diastereomeric structure of B is
quite analogous to that of the (isolated) platinum(IV)
complex shown in Scheme 1. Due to the higher trans
influence of the P donor over Cl, the acetyl group
trans to phosphorus (L in intermediate B) should un-
dergo reductive elimination yielding directly the ther-
modynamically favoured trans complexes 2. The un-
symmetrical dadpe ligand should attack the platinum-
b-diketone 1 through the stronger donor (phosphorus)
1H NMR (400 MHz, CD2Cl2): d = ±0.09 (t, 3J(H, H) = 6 Hz, 3 H, CH3),
1.52 (q, 3J(H, H) = 6 Hz, 2 H, CH2), 3.84 (s, 18 H, OCH3), 6.95 (`d', 12 H,
m-CH), 7.65 (m, 12 H, o-CH). 13C NMR (100 MHz, CD2Cl2): d = 8.2
(CH3), 51.1 (t+d(br), 3J(P, C) = 5.6 Hz, 2J(Pt, C) ca 180 Hz, CH2), 55.5
(OCH3), 113.8 (`t', N = 3+5J(P, C) = 11.6 Hz, Cm), 122.3 (`t', N =
1+3J(P, C) = 60.5 Hz, Ci), 136.5 (`t', N = 2+4J(P, C) = 13.6 Hz, Co), 161.4
(Cp), 219.8 (t+d(br), 2J(P, C) = 6.0 Hz, 1J(Pt, C) ca 950 Hz, CO). 31P NMR
(81 MHz, CD2Cl2): d = 17.9 (s+d, 1J(Pt, P) = 3449 Hz). IR: m = 1649 (s,
CO), 260 (w, PtCl) cm±1
.
Synthesis of trans-[Pt(COMe)Cl{P(p-CH2=CHC6H4)Ph2}2]
(2 b) and trans-[Pt(COMe)Cl{P(n-Bu3}2] (2 c)
To [Pt2{(COMe)2H}2(l-Cl)2] (1) (32.4 mg, 0.05 mmol) in
CD2Cl2 (1 ml) the phophine (0.21 mmol) was added. After
10±20 min the pale-yellow solution was investigated by
NMR spectroscopy.
2 b: 1H NMR (400 MHz, CD2Cl2): d = 1.20 (s, 3 H, CH3), 5.40 (d,
3J(Ha, Hc)3) = 10.8 Hz, 2 H, Hc), 5.87 (d, 3J(Ha, Hb) = 17.6 Hz, 2 H, Hb),
6.78 (dd, 3J(Ha, Hc) = 11.0 Hz, 3J(Ha, Hb) = 17.8 Hz, 2 H, Ha,), 7.55 (m,
16 H, Ph), 7.78 (m, 12 H, Ph). 13C NMR (100 MHz, CD2Cl2): d = 44.1
(t+d(br), 3J(P, C) = 6.4 Hz, 2J(Pt, C) ca 200 Hz, CH3), 116.1 (CH=CH2),
136.2 (CH=CH2), 216.1 (t, 2J(P, C) = 5.8 Hz, CO); Carom4): 126.1 (`t',
N = 10.7 Hz), 128.5 (`t', N = 10.8 Hz), 131, 135.1 (`t', N = 12.5 Hz), 135.4
(`t', N = 12.4 Hz), 140.2. 31P NMR (81 MHz, CD2Cl2): d = 20.8 (s+d,
1J(Pt, P) = 3501 Hz).
yielding the (unseen) intermediate
B
(L L' =
P
As). Due to the higher trans influence of the P do-
nor over the chloro ligand the acyl group trans to P
should undergo reductive elimination in such a way
that the thermodynamically more stable isomer 3 a is
formed.
3)
CHbHc=CHa±: Hb/Hc ± trans/cis to Ha.
6 of 8 aromatic carbon atoms were detected.
4)
664
Z. Anorg. Allg. Chem. 2000, 626, 661±666

On the Reactivity of Platina-û-diketones ± Synthesis and Characterization of Acylplatinum(II) Complexes
2 c: 1H NMR (200 MHz, CD2Cl2): d = 0.88 (t, 18 H, CH2CH3), 1.45 (m,
Table 4 Crystal data and structure refinement for trans-
[Pt(COMe)Cl{P(p-FC6H4)3}2] 2 a and [Pt(COMe)Cl(dadpe)]
3 a.
24 H, CH2), 1.76 (m, 12 H, CH2), 2.16 (s+d, 3J(Pt, H) = 12.8 Hz, 3 H,
COCH3). 13C NMR (100 MHz, CD2Cl2): d = 13.7 (CH2CH3), 21.9 (`t',
N = 3+5J(P, C) = 32.4 Hz, CH2CH3), 24.4 (`t', N = 2+4J(P, C) = 17.5 Hz,
PCH2CH2), 26.2 (s+d, 2J(Pt, C) = 25.3 Hz, PCH2), 47.1 (t+d,
3J(P, C) = 4.4 Hz, 2J(Pt, C) = 287 Hz, COCH3), 215.8 (t, 2J(P, C) = 6.8 Hz,
CO). 31P NMR (81 MHz, CD2Cl2): d = 8.2 (s+d, 1J(Pt, P) = 3075 Hz).
formula
formula weight
T, K
C38H27ClF6OP2Pt
906.08
150(2)
C28H27AsClOPPt
715.93
150(2)
crystal system, space group
monoclinic, P21
(no. 4)
monoclinic, P21/n
(no. 14)
Synthesis of [Pt(COMe)Cl(dadpe)] (3 a)
To [Pt2{(COMe)2H}2(l-Cl)2] (1) (65.0 mg, 0.10 mmol) in
acetone (2 ml) a solution of dadpe (88 mg, 0.20 mmol) in
acetone (2 ml) was added dropwise at ±30 °C. The reaction
mixture was slowly warmed to room temperature and inves-
tigated by means of 31P NMR spectroscopy exhibiting a ratio
3 a : 3 b of about 9 : 1 (31P NMR (81 MHz, CD2Cl2): d = 32.2
(s+d, 1J(Pt, P) = 4454 Hz, P(3 a)), 43.7 (s+d, 1J(Pt, P) =
1720 Hz, P(3 b))). After standing 12 hours, the crystals of 3a
were filtered off and dried in vacuo. Yield: 56 mg (78%).
Ê
a, b, c, A
11.1640(6),
14.6189(8),
11.8404(6)
115.176(1)
1748.9(2)
2
8.9883(1),
27.2048(4),
12.1843(2)
105.13(1)
2876.13(7)
4
b, °
3
Ê
V, A
Z
qcalc, g cm±3
1.721
4.242
1.653
6.186
l, mm±1
h range, °
limiting indices
2.36±26.00
±8 £ h £ 13;
±17 £ k £ 17;
±14 £ l £ 12
10351
6669
[R(int) = 0.0545]
5622
2.29±29.59
±11 £ h £ 11;
±37 £ k £ 27;
±16 £ l £ 11
35992
6207
[R(int) = 0.0145]
5857
1H NMR (400 MHz, CD2Cl2): d = 1.89 (s(br), 3 H, CH3), 2.05 (m, 2 H,
CH2), 2.51 (m, 2 H, CH2), 7.46±7.78 (m, 20 H, Ph). 13C NMR (100 MHz,
CD2Cl2): d = 21.2 (d, 2J(P, C) = 6.0 Hz, AsCH2), 30.0 (d+d,
1J(P, C) = 41 Hz, 2J(Pt, C) = 195 Hz, PCH2), 41.3 (d, 3J(P, C) = 5 Hz,
CH3), 128.8 (d, 1J(P, C) = 60 Hz, Ci(P)), 129.3 (d, 3J(P, C) = 10 Hz,
Cm(P)), 129.6 (Cm(As)), 130.8 (Cp(P)5)), 131.9 Hz, (Ci(As)5)), 133.1
(Co(As)), 133.6 (d, 2J(P, C) = 11 Hz, Co(P)), 133.9 (Cp(As)5)), 231.5 (CO).
refl. collected
refl. unique
refl. observed [I > 2r(I)]
data/restraints/parameters
Goodness-of-fit on F2
R1 (obs. data)
6669/1/442
1.182
0.0707
6207/0/299
1.245
0.0509
wR2 (all data)
0.1615
0.1422
absolute structure parameter ±0.02(2)
±
Crystallographic studies
±3
Ê
largest peak/hole, e A
3.212/±1.519
2.551/±2.196
Intensity data for 2 a and 3 a were collected on a Siemens
Ê
Smart diffractometer with MoKa radiation (0.71073 A, gra-
phite monochromator). A summary of crystallographic data,
data collection parameters, and refinement parameters is gi-
ven in Table 4. 2 a and 3 a were corrected for absorption em-
pirically and numerically, respectively. The structures were
solved by direct methods with SHELXS-86 [14] and refined
using full-matrix least-squares routines against F2 with
SHELXL-93 [14]. Non-hydrogen atoms were refined with
anisotropic displacement parameters. The hydrogen atom
positions were calculated and allowed to ride on the corre-
sponding carbon atoms. The isotropic displacement para-
meters were tied to those of the adjacent carbon atoms by a
factor of 1.2.
substituents at phosphorus were formally replaced by phenyl
rings which were optimized with the semiempirical method
PM3.
This work is supported by the Deutsche Forschungsge-
meinschaft and by the Fonds der Chemischen Industrie.
Gifts of chemicals by the companies Degussa (Hanau) and
Merck (Darmstadt) are gratefully acknowledged.
References
Crystallographic data (excluding structure factors) for 2 a
and 3 a have been deposited at the Cambridge Crystallo-
graphic Data Center as supplementary publication no.
CCDC-137940 (2 a) and 137941 (3 a), respectively. Copies of
the data can be obtained free of charge on application to
CCDC, 12 Union Road, Cambridge, CB2, 1EZ, UK [Fax:
(internat.) +44(0)1223/336-033; E-mail: deposit@ccdc.cam.
ac.uk].
[1] D. Steinborn, M. Gerisch, K. Merzweiler, K. Schenzel,
K. Pelz, H. BoÈgel, J. Magull, Organometallics 1996, 15,
2454.
[2] D. Steinborn, M. Gerisch, T. Hoffmann, C. Bruhn, G. Is-
rael, F. W. MuÈller, J. Organomet. Chem., in press.
[3] C. M. Lukehart, Adv. Organomet. Chem. 1986, 25, 45.
[4] D. Steinborn, M. Gerisch, C. Bruhn, J. A. Davies, Inorg.
Chem. 1999, 38, 680.
[5] M. Gerisch, C. Bruhn, A. Vyater, J. A. Davies, D. Stein-
born, Organometallics 1998, 17, 3101.
Quantum Chemical Calculations
[6] D. Steinborn,
A. Vyater,
C. Bruhn,
M. Gerisch,
DFT (B3LYP/LANL2DZ and BP86/LANL2DZ) closed
shell calculations were carried out for model complexes cis/
trans-[Pt(COMe)Cl(PR3)2] (R = H 4 a/b, Me 5 a/b, Ph 6 a/b),
using effective core approximations for the core orbitals of
platinum [15] and a double zeta split for the other orbitals
applying the Gaussian 98 package [16]. Complexes 4 and 5
were fully optimized and characterized as equilibrium struc-
tures by the analysis of the vibrational frequencies. Due to
the large number of atoms, for complexes 6 the optimized
structures of complexes 5 were used in which the methyl
H. Schmidt, J. Organomet. Chem., in press.
[7] M. Gerisch, F. W. Heinemann, C. Bruhn, J. Scholz,
D. Steinborn, Organometallics, 1999, 18, 564.
[8] a) P. S. Pregosin, R. W. Kunz, 31P and 13C NMR of Tran-
sition Metal Phosphine Complexes in NMR Basic Prin-
ciples and Progress (eds. P. Diehl, E. Fluck, R. Kosfeld),
Springer-Verlag, Berlin 1979. b) J. G. Verkade,
L. D. Quin (eds.), Phosphorus-31 NMR Spectroscopy in
Stereochemical Analysis, VCH Publishers, Deerfield
Beach 1987.
[9] a) S. P. Dent, C. Eaborn, A. Pidcock, J. Organomet.
Chem. 1975, 97, 307. b) R. Bardi, A. M. Piazzesi, G. Ca-
5)
Assignment uncertain.
Z. Anorg. Allg. Chem. 2000, 626, 661±666
665

D. Steinborn et al.
vinato, P. Cavoli, L. Toniolo, J. Organomet. Chem. 1982,
224, 407. c) A. Scrivanti, A. Berton, L. Toniolo, C. Bot-
teghi, J. Organomet. Chem. 1986, 314, 369. d)
H. J. Ruegg, P. S. Pregosin, A. Scrivanti, L. Toniolo,
C. Botteghi, J. Organomet. Chem. 1986, 316, 233. e)
A. Scrivanti, C. Botteghi, L. Toniolo, A. Berton, J. Or-
ganomet. Chem. 1988, 344, 261. f) G.-L. Huang, T.-
M. Huang, J.-T. Chen, Inorg. Chem. 1992, 31, 4034.
[10] T. G. Appleton, H. C. Clark, L. E. Manzer, Coord.
Chem. Rev. 1973, 10, 335.
[13] J.-T. Chen, Y.-S. Yeh, C.-S. Yang, F.-Y. Tsai, G.-
L. Huang, B.-C. Shu, T.-M. Huang, Y.-S. Chen, G.-
H. Lee, M.-C. Cheng, C.-C. Wang, Y. Wang, Organome-
tallics 1994, 13, 4804 and literature cited therein.
[14] G. M. Sheldrick, SHELXS-86, SHELXL-93, Programs
for Crystal Structure Determination, University of GoÈt-
tingen, GoÈttingen, 1986, 1993.
[15] K. B. Lipdeowitz, D. B. Boyd, Rev. Comput. Chem.
1996, 8, 63.
[16] Gaussian 98, Gaussian Inc., Pittsburgh (PA) 1998.
[17] J. C. Tebby (ed.), CRC Handbook of Phosphorus-31 Nu-
clear Magnetic Resonance Data, CRC Press, Boca Ra-
ton 1991.
[11] Cambridge Structural Database (CSD), Cambridge
Crystallographic Data Centre, University Chemical La-
boratory, Cambridge (UK).
[12] a) R. J. Klingler, J. C. Huffman, J. K. Kochi, J. Am.
Chem. Soc. 1982, 104, 2147. b) G. K. Anderson,
R. J. Cross, L. Manojlovic-Muir, K. W. Muir, T. Solo-
mun, J. Organomet. Chem. 1979, 170, 385.
[18] M. N. Burnett, C. K. Johnson, ORTEP-III: Oak Ridge
Thermal Ellipsoid Plot Program for Crystal Structure Il-
lustrations, Oak Ridge National Laboratory Report
ORNL-6895, 1996.
666
Z. Anorg. Allg. Chem. 2000, 626, 661±666