trans-Arylplatinum(II) methyl compounds containing a bis(imino)aryl [NCN] ligand

Article abstract of DOI:10.1021/om0343972

The synthesis and the first X-ray crystal structure of stable trans-arylplatinum methyl complexes [Pt(CH₃)NCN] with imine type N ligands are reported. These are interesting examples of compounds on the reaction coordinate of C-C bond-forming and bond-breaking reactions, which have so far not been observed in the known series of Pt(II) complexes featuring an amine type N-C-N pincer ligand. Due to the strong C(sp²)-C(sp³) bond, only very few transition-metal compounds having an aryl as well as a methyl group bonded to the same metal atom are known and, usually, reductive elimination occurs. In case of the title compounds, this is prevented due to the trans disposition of the methyl and aryl groups and the rigid coplanarity of the chelate rings. This prevents deformation of the N-C-N tridentate ligand in the coordination plane.

Full text of DOI:10.1021/om0343972

Organometallics 2004, 23, 1161-1164
1161
tr a n s-Ar ylp la tin u m (II) Meth yl Com p ou n d s Con ta in in g a
Bis(im in o)a r yl [NCN] Liga n d
Wilhelmus J . Hoogervorst,† Anne L. Koster,† Martin Lutz,‡
Anthony L. Spek,‡ and Cornelis J . Elsevier*,†
Institute of Molecular Chemistry, Universiteit van Amsterdam, Nieuwe Achtergracht 166,
NL-1018 WV Amsterdam, The Netherlands, and Bijvoet Center for Biomolecular Research,
Vakgroep Kristal- en Struktuurchemie, Utrecht University,
Padualaan 8, NL-3584 CH Utrecht, The Netherlands
Received December 22, 2003
Ch a r t 1
Summary: The synthesis and the first X-ray crystal
structure of stable trans-arylplatinum methyl complexes
[Pt(CH3)NCN] with imine type N ligands are reported.
These are interesting examples of compounds on the
reaction coordinate of C-C bond-forming and bond-
breaking reactions, which have so far not been observed
in the known series of Pt(II) complexes featuring an
amine type N-C-N “pincer” ligand. Due to the strong
C(sp2)-C(sp3) bond, only very few transition-metal
compounds having an aryl as well as a methyl group
bonded to the same metal atom are known and, usually,
reductive elimination occurs. In case of the title com-
pounds, this is prevented due to the trans disposition of
the methyl and aryl groups and the rigid coplanarity of
the chelate rings. This prevents deformation of the
N-C-N tridentate ligand in the coordination plane.
of the other known trans-diorganoplatinum(II) com-
pounds the remaining two (neutral) ligands bound to
the platinum are forced into a trans configuration by
using a meridionally coordinating and covalently bound
[D-C-D] ligand (A; Chart 1).
Since the first report of a platinum(II) [P-C-P]
compound,13 many papers concerning platinum(II)
[D-C-D] compounds, bearing different donor groups,
have appeared; the forced trans coordinating mode of
the donor groups has resulted in trans-diorganoplati-
num(II) compounds which contain [P-C-P]14-16 and
[N-C-N]17-19 ligands.
When platinum(II) methyl compounds containing a
[D-C-D] ligand are considered, it appears that only
two examples of trans isomers have been documented;
these are the platinum [P-C-P] methyl compounds B
and B′ (Chart 1; R ) Ph).14,16 However, none has been
authenticated by means of a crystal structure determi-
nation. To the best of our knowledge, no trans-arylplati-
num(II) methyl compound has ever been crystallograph-
ically authenticated. Only one crystal structure of a
trans aryl-Pt-C(sp3) compound has appeared at all; in
this diphenylphosphine-substituted [P-C-P] platinum
compound,16 a σ-bonded n-C3F7 group is coordinated to
platinum trans to the aryl carbon; i.e., electronic
stabilization has been gained by introducing a perfluoro-
alkyl moiety.
Geometric isomers of the square-planar diorgano-
platinum(II) compounds PtR2L2 are relevant to mecha-
nistic considerations concerning C-C bond formation1-4
and to fundamental structural investigations. The
strong trans influence exerted by hydrocarbyl ligands
will bias the geometry of tetracoordinate diorganoplati-
num(II) compounds toward cis complexes when L is a
monodentate or L2 is a bidentate ancillary ligand, and
even when RL2 is a tridentate ligand, unless chelate
effects are overriding.5-7 Much fewer examples are
known of trans diorganoplatinum(II) compounds. Some
of these platinum compounds have two monodentate
phosphine ligands,8-11 in which case isomerization to
the thermodynamically more stable cis-diorganoplati-
num(II) diphosphine compounds may occur.12 In most
* To whom correspondence should be addressed. E-mail: elsevier@
science.uva.nl.
† Universiteit van Amsterdam.
‡ Utrecht University.
(1) Low, J . J .; Goddard, W. A., III. J . Am. Chem. Soc. 1986, 108,
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123, 7233-7246.
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1792.
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Ferguson, G.; Puddephatt, R. J . Organometallics 1991, 10, 2672-2679.
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L. Organometallics 2001, 20, 4741-4744.
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Ooyevaar, I. C. M.; Muller, F.; Stam, C. H. Organometallics 1990, 9,
903-912.
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10.1021/om0343972 CCC: $27.50 © 2004 American Chemical Society
Publication on Web 02/03/2004

1162 Organometallics, Vol. 23, No. 5, 2004
Notes
Sch em e 1. Syn th esis of Title Com p ou n d s
Ch a r t 2
F igu r e 1. Displacement ellipsoid plot of 2a , drawn at the
50% probability level. All hydrogen atoms except those of
the methyl group have been omitted for clarity. Selected
distances (Å), angles (deg), and torsion angles (deg): Pt-
N1 ) 2.045(2), Pt-N2 ) 2.036(2), Pt-C1 ) 1.944(2), Pt-
C33 ) 2.156(3), N1-C7 ) 1.314(3), N1- C9 ) 1.442(3),
N2-C8 ) 1.304(3), N2-C21 ) 1.439(3); N1-Pt-N2 )
157.63(8), N1-Pt-C1 ) 78.93(9), N1-Pt-C33 ) 102.22(10),
C1-Pt-C33 ) 173.49(12), N2-Pt-C1 ) 78.80(9), N2-Pt-
C33 ) 100.15(10), C7-N1-C9 ) 118.9(2), C8-N2-C21 )
120.7(2); Pt-C1-C2-C8 ) -5.2(3), Pt-C1-C6-C7 )
4.2(3).
We now report the synthesis of thermally stable, novel
trans-bis(imino)arylplatinum(II) methyl compounds 2
and the crystal structure of one of these, which were
readily accessible from the corresponding platinum(II)
halide compounds 1 (see Scheme 1) by transmetalation.
The bis(imino)arylplatinum(II) bromide compounds
1a ,c were described in our recent paper on acetylide
derivatives 3 and 4 (see Chart 2);20 1b was prepared
similarly.
sample of the reaction mixture, but it readily decom-
posed and could not be isolated.
3
The J (1H,195Pt) values of the imine protons of 2a ,b
(125 Hz) are substantially lower than those of 1a ,b (144
Hz) due to the larger cis influence of the methyl group
compared to the bromide. In agreement with the nephel-
auxetic effect previously discussed,21 the 195Pt chemical
shift increases from -3563 ppm in 1a (-3517 ppm in
1b) to -3096 ppm in 2a (-3074 ppm in 2b).
A single-crystal X-ray structure determination of 2a
provided proof of its molecular structure, which is
depicted in Figure 1; it constitutes the first crystal
structure of a mononuclear trans-arylplatinum methyl
compound. The molecular structure of 2a reveals bond
lengths and angles that are similar to those in the
acetylide 3:20 notably the lengths of their Pt-N bonds
and the Pt-Caryl bond. The platinum has a distorted-
square-planar environment with a sum of cis angles of
360.1°. The short imine CdN bonds lead to a large
deviation from linearity of the trans N-Pt-N angle,
amounting to 157.63(89)° in 2a , which is similar to that
in 3 (157.21(9)°).
Synthesis of the thermally stable methyl derivatives
2 was attempted first by transmetalation of the respec-
tive bis(imino)arylplatinum(II) bromide compounds 1a-c
with methyllithium, an approach which has been suc-
cessful in the case of [P-C-P] ligands.14,16 However,
when compounds 1a ,c were reacted with methyllithium
at low temperature in THF, the orange reaction mixture
immediately turned green. No Pt-CH3 resonance was
1
observed in the H NMR spectra of the reaction mix-
tures. Probably, only undesired reactions such as elec-
tron transfer, proton abstraction, and addition to the
imine moiety had occurred. Next, dimethylzinc was
applied as a less basic and less nucleophilic methyl
transfer reagent. Indeed, the transmetalation of 1a was
successfully performed (Scheme 1) at room temperature
in THF by addition of excess dimethylzinc, upon which
the color of the light orange reaction mixture slowly
turned to dark red. 1H NMR spectroscopic analysis
pointed to the clean formation of a new methylplatinum
compound (a correctly integrated Pt-CH3 resonance at
The Pt-Cmethyl bond is relatively long (2.156(3) Å), in
agreement with the large mutual trans influence of the
aryl and methyl groups, and is significantly longer than
in compounds with, for example, N ligands in trans
positions and/or with cis hydrocarbyl groups.22-25 How-
ever, similar values have been reported for platinum
3
0.7 ppm, J (1H,195Pt) ) 53 Hz, C6D6) which has struc-
tural features similar to those of 1a . Pure 2a was
isolated as red prisms in 95% yield. Similarly treating
compound 1b with an excess of dimethylzinc at room
temperature afforded the analogous bis(imino)arylplati-
num(II) methyl compound 2b in 80% isolated yield.
It appeared that such bis(imino)arylplatinum(II)
methyl compounds could be isolated only for sterically
demanding aryl substituents on the imine moieties; for
compound 1c (R ) 4-methoxyphenyl) the platinum(II)
methyl compound 2c was observed by 1H NMR in a
methyl complexes with a trans phosphine ligand.26,27
A
large trans influence has also been observed in the
crystal structure of the trans-arylplatinum C3F7 com-
pound,16 where the Pt-CF2R bond length is 2.186(8) Å.
The five- and six-membered rings in the coordination
plane of platinum are almost planar; for the Pt(1), N(1),
C(1), C(6), C(7) plane, the largest deviation is 0.026(2)
(20) Hoogervorst, W. J .; Elsevier, C. J .; Lutz, M.; Spek, A. L.
Organometallics 2001, 20, 4437-4440.
(21) Pregosin, P. S. Coord. Chem. Rev. 1982, 44, 247-291.

Notes
Organometallics, Vol. 23, No. 5, 2004 1163
distilled prior to use, according to standard methods.32 195Pt
NMR spectroscopy was measured via a normal HMQC se-
quence on a Bruker DRX300 spectrometer at 64.3 MHz at 298
K. Positive chemical shifts (δ) are denoted for high-frequency
shifts relative to a TMS reference (1H, 13C) and an Na2PtCl6
reference (195Pt). HRMS measurements were performed on a
J EOL J MS SX/SX102A four-sector mass spectrometer, coupled
to a J EOL MS-MP9021D/UPD system program. For fast atom
bombardment (FAB) mass spectrometry, the samples were
loaded in a matrix solution (3-nitrobenzyl alcohol) onto a
stainless steel probe and bombarded with xenon atoms with
an energy of 3 keV. During the high-resolution FAB-MS
measurements a resolving power of 10 000 (10% valley defini-
tion) was used.
Ch a r t 3
Å, for the Pt(1), N(1), C(1), C(2), C(8) plane this is 0.034-
(2) Å, and for the aryl ring the largest deviation from
planarity is 0.009(2) Å. These three planes are almost
coplanar, the angles between these rings varying from
0.71(10) to 2.97(11)°.
Ma ter ia ls. 2-Bromoisophthalaldehyde33 and Pt(dipdba)2
34
were prepared according to literature procedures. Molecular
sieves (3 Å) were activated by heating at 150 °C in vacuo
overnight. All other starting materials were obtained from
commercial sources and used as received.
In compounds 2a ,b the trans disposition of the aryl
and the methyl groups is dictated by the strong coor-
dination of the chelating imine moieties. Possibly, the
relative stability of 2a ,b can be ascribed to the rigidity
of the fused five-membered-ring systems, which, due to
the imine moieties, must remain essentially coplanar,
allowing only small deviations from planarity.
Furthermore, since compound 2c could not be iso-
lated, the presence of large ortho substituents on the
N-aryl ring probably also plays a role in preventing
decomposition.
For related amine type N-C-N (“pincer”) compounds,
arylplatinum(II) methyl derivatives have been neither
observed nor isolated. Instead, Pt(II)-arenium com-
pounds of type D (see Chart 3) have been isolated, which
arise via oxidative addition of methyl halide to a Pt(II)
precursor, followed by a 1,2-methyl shift from the
resulting Pt(IV) to the ipso carbon of the arene ring.28-30
For phosphine type P-C-P compounds, a few arylmetal
methyl compounds have been isolated, notably for Rh,
but these are cis high-valent d6 complexes.4,31
Bis(N -2,6-d im e t h ylp h e n yl)-2-b r om oisop h t h a la ld i-
m in e. To a solution of 2-bromoisophthalaldehyde (1.5 g, 7.0
mmol) in 50 mL of toluene was added 2,6-dimethylaniline (2
mL, 2.1 g, 17.6 mmol) and 3 Å molecular sieves. The reaction
mixture was stirred overnight at 60 °C and filtered, after which
the solvent was evaporated under reduced pressure. The
residue was washed with 50 mL of pentane and dried in vacuo
to yield 2.45 g (5.8 mmol, 84%) of a yellow solid which was
identified by 1H and 13C NMR spectroscopy as the pure
compound. 1H NMR (500 MHz, CDCl3): δ 8.75 (s, 2H; HCd
3
3
N), 8.41 (d, J HH ) 7.5 Hz, 2H), 7.58 (t, J HH ) 7.5 Hz, 1H),
7.11 (bs, 6H), 2.20 (s, 12H). 13C NMR (126 MHz, CDCl3): δ
162.1 (CdN), 151.1 (C), 135.9 (C), 131.7 (CH) 128.7 (C-Br),
128.5 (CH), 128.2 (CH), 127.3 (C), 124.4 (CH), 18.7 (CH3).
HRMS (FAB): m/z calcd ([M + H]+ C24H24N279Br) 419.1123,
found 419.1124. Anal. Calcd for C24H23BrN2: C, 68.74; H, 5.53;
N, 6.68. Found: C, 68.88 H, 5.48; N, 6.65.
[KC,KN,KN′-Bis(N-2,6-dim eth ylph en yl)isoph th alaldim in -
2-yl]p la tin u m (II) Br om id e (1b). To a solution of bis(N-2,6-
dimethylphenyl)-2-bromoisophthalaldimine (1.0 g, 2.4 mmol)
in 30 mL of THF was added Pt(dipdba)2 (3.5 g, 3.0 mmol), and
In conclusion, compounds 2a ,b constitute interesting
examples of compounds on the reaction coordinate of
C-C bond-forming and bond-breaking reactions, which
have so far not been observed in the known series of
Pt(II) complexes featuring an amine type N-C-N or
phosphine type P-C-P “pincer” ligand.
1
the reaction mixture was stirred overnight at 60 °C. H NMR
spectroscopic analysis showed a partial conversion, and there-
fore another portion of Pt(dipdba)2 (1.1 g, 1.4 mmol) was added.
When the reaction was complete, the reaction mixture was
cooled to room temperature, upon which the product crystal-
lized. The reaction mixture was filtered over Celite, and the
product was extracted from the residue with dichloromethane.
The solvent was evaporated under reduced pressure, and the
product was dried in vacuo to yield 1.3 g (2.1 mmol, 88%) of a
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions involving air-sensitive
compounds were carried out under a dinitrogen atmosphere
using standard Schlenk techniques. Solvents were dried and
1
bright orange solid which was identified by H, 13C, and 195Pt
1
NMR spectroscopy as pure 1b. H NMR (300 MHz, CDCl3): δ
3
3
8.44 (s, J HPt ) 144 Hz, 2H; HCdN), 7.71 (d, J HH ) 7.5 Hz,
3
(22) Anderson, C.; Crespo, M.; Font-Bardia, M.; Klein, A.; Solans,
X. J . Organomet. Chem. 2000, 601, 22-33.
2H), 7.32 (t, J HH ) 7.5 Hz, 1H), 7.10 (bs, 6H), 2.27 (s, 12H;
CH3). 13C NMR (126 MHz, CDCl3): δ 179.1 (2J CPt, ) 106 Hz,
(23) Doppiu, A.; Agostina Cinellu, M.; Minghetti, G.; Stoccoro, S.;
Zucca, A.; Manassero, M.; Sansoni, M. Eur. J . Inorg. Chem. 2000,
2555-2563.
1
CdNC), 178.4 (C-Pt, J CPt ) 935 Hz), 148.1 (CdNC), 142.1
(3J CPt ) 116 Hz, C), 131.3 (3J CPt ) 10 Hz, C), 128.1 (CH), 128.0
(CH), 127.5 (CH), 123.0 (CH), 18.5 (CH3). 195Pt NMR (CDCl3):
(24) Fang, X.; Scott, B. L.; Watkin, J . G.; Kubas, G. J . Organome-
tallics 2000, 19, 4193-4195.
δ -3562. HRMS (FAB): m/z calcd ([M + H]+ C24H24N279Br195
-
(25) Hinman, J . G.; Baar, C. R.; J ennings, M. C.; Puddephatt, R. J .
Organometallics 2000, 19, 563-570.
Pt) 614.0773, found 614.0714.
(26) Hartley, F. R. In Comprehensive Organometallic Chemistry;
Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon Press:
Oxford, U.K., 1982; Vol. 6, p 471.
Met h yl [KC, κN, K N′-b is(N-2,6-d iisop r op ylp h en yl)iso-
p h th a la ld im in -2-yl]p la tin u m (II) (2a ). To a solution of 1a
(113 mg, 0.16 mmol) in 20 mL of THF was added dimethylzinc
(2 mL of a 2.0 M solution in toluene, 4 mmol). In 10 min the
orange reaction mixture turned red, and the reaction was very
gently quenched with water. Most of the THF was evaporated
(27) Anderson, G. K. In Comprehensive Organometallic Chemistry
II: A Review of the Literature 1982-1994; Abel, E. W., Stone, F. G.
A., Wilkinson, G., Eds.; Pergamon Press: Oxford, U.K., 1995; Vol. 9,
p 431.
(28) Terheijden, J .; van Koten, G.; Vinke, I. C.; Spek, A. L. J . Am.
Chem. Soc. 1985, 107, 2891-2898.
(29) Albrecht, M.; van Koten, G. Angew. Chem., Int. Ed. 2001, 40,
3750-3781.
(32) Perrin, D. D.; Armarego, L. F. Purification of Laboratory
Chemicals; Pergamon Press: Oxford, U.K., 1998.
(33) Gelling, O. J .; Feringa, B. L. Recl. Trav. Chim. Pays-Bas 1991,
110, 89-91.
(34) Keasey, A.; Mann, B. E.; Yates, A.; Maitlis, P. M. J . Organomet.
Chem. 1978, 152, 117-123.
(30) Albrecht, M.; Spek, A. L.; van Koten, G. J . Am. Chem. Soc. 2001,
123, 7233-7246.
(31) Rybtchinski, B.; Milstein, D. Angew. Chem., Int. Ed. 1999, 38,
870-883.

1164 Organometallics, Vol. 23, No. 5, 2004
Notes
under reduced pressure, and the mixture was extracted three
times with 30 mL of pentane. The organic layer was washed
subsequently with water and a concentrated NaHCO3 solution
and dried on MgSO4. After filtration the solvents were
evaporated in vacuo. The residue was extracted with 200 mL
of pentane. The pentane was removed under reduced pressure,
and the solid material was washed two times with a small
amount of pentane and dried in vacuo to yield 98 mg (0.15
mmol, 95%) of an orange-red solid which was identified by 1H,
13C, and 195Pt NMR spectroscopy as pure 2a . 1H NMR (300
11.2859(1) Å, b ) 14.6377(1) Å, c )17.7437(1) Å, V ) 2931.25-
(4) Å3, Z ) 4, Dx ) 1.500 g/cm3, µ ) 4.810 mm-1. A total of
34 018 reflections were measured on a Nonius KappaCCD
diffractometer with rotating anode (λ ) 0.710 73 Å) at a
temperature of 150(2) K up to a resolution of ((sin θ)/λ)max
)
0.65 Å-1; 6705 reflections were unique (Rint ) 0.036). An
analytical absorption correction was applied (0.47-0.72 trans-
mission). The structure was solved with automated Patterson
methods (DIRDIF-97)35 and refined with SHELXL-9736 against
F2 values of all reflections. Non-hydrogen atoms were refined
freely with anisotropic displacement parameters. H atoms of
the imine group were refined freely with isotropic displacement
parameters; all other H atoms were refined as rigid groups
(334 refined parameters, no restraints). R values (I > 2σ(I)):
R1 ) 0.0153, wR2 ) 0.0359. R values (all reflections): R1 )
0.0158, wR2 ) 0.0361. The Flack x parameter37 is -0.016(4),
the GOF value is 1.050, and the residual electron density is
between -0.67 and 0.57 e/Å3. Molecular illustration, structure
checking and calculations were performed with the PLATON
package.38
3
MHz, C6D6): δ 8.14 (s, J HPt ) 125 Hz, 2H; HCdN), 7.42 (d,
3J HH ) 7.5 Hz, 2H), 7.07 (m, obscured by solvent), 6.92 (t, 3J HH
3
) 7.5 Hz, 1H), 3.31 (septet, J HH ) 6.8 Hz, 4H; CH3CHCH3),
3
3
1.28 (d, J HH ) 7 Hz, 12H; CH3CHCH3), 0.98 (d, J HH ) 7 Hz,
12H; CH3CHCH3), 0.67 (s, J HPt ) 53 Hz, Pt-CH3). 13C NMR
3
(126 MHz, C6D6): δ 204.6 (C-Pt), 180.3 (2J CPt ) 56 Hz, Cd
N), 146.7 (C), 143.2 (2J CPt ) 89 Hz, C), 141.4 (C), 127.4 (CH),
126.6 (CH), 123.1 (CH), 121.7 (CH), 27.6 (CH3CHCH3), 24.2
(CH3CHCH3), 22.8 (CH3CHCH3), 10.2 (1J CPt ) 623 Hz, Pt-
CH3). 195Pt NMR (C6D6): δ -3074. HRMS (FAB): m/z calcd
([M + H]+ C33H43N2Pt) 662.3077, found 662.3040. Anal. Calcd
for C33H42N2Pt: C, 59.89; H, 6.40; N, 4.23. Found: C, 60.09;
H, 6.35; N, 4.17. Single crystals suitable for X-ray structure
determination were obtained by cooling a concentrated toluene
solution.
Ack n ow led gm en t. This work was supported in part
(W.J .H., A.L.S., M.L.) by The Netherlands Foundation
for Chemical Sciences (CW) with financial aid from The
Netherlands Organization for Scientific Research (NWO).
Meth yl[KC,KN,KN′-bis(N-2,6-dim eth ylph en yl)isoph th al-
a ld im in -2-yl]p la tin u m (II) (2b). Compound 2b was prepared,
in analogy to 2a , from 1b (159.1 mg, 0.259 mmol) and
dimethylzinc (2 mL of a 2.0 M solution in toluene, 4 mmol).
During the workup, hexane was used instead of pentane. The
yield was 114 mg (0.21 mmol, 80%) of an orange-red solid
Su p p or tin g In for m a tion Ava ila ble: X-ray CIF file for
2a . This material is available free of charge via the Internet
at http://pubs.acs.org. CCDC 215854 contains the supplemen-
tary crystallographic data for this paper. These data can be
obtained free of charge via www.ccdc.cam.ac.uk/conts/retriev-
ing.html (or from the CCDC, 12 Union Road, Cambridge CB2
1EZ, U.K.; fax +44 1223 336033; e-mail deposit@ccdc.cam.
ac.uk).
1
which was identified by H, 13C, and 195Pt NMR spectroscopy
as pure 2b. The workup has to be performed quickly, since
otherwise an increasing amount of a decomposition product,
1
which is insoluble in hexane, is formed. H NMR (300 MHz,
3
3
C6D6): δ 7.63 (s, J HPt ) 125 Hz, 2H; HCdN), 7.42 (d, J HH
)
3
7.5 Hz, 2H), 6.95 (t, J HH ) 7.5 Hz, 1H), 6.86 (br s, 6H), 2.07
(s, 12H), 0.66 (s, 3J HPt ) 53 Hz, Pt-CH3). 13C NMR (126 MHz,
C6D6): δ 204.0 (1J CPt ) 591 Hz, C-Pt), 180.6 (2J CPt ) 52 Hz,
CdN), 149.2, 143.4 (2J CPt ) 91 Hz), 131.1, 129.3, 126.6, 126.5,
121.6, 18.4 (Ar-CH3), 8.7 (1J CPt ) 604 Hz, Pt-CH3). 195Pt NMR
(C6D6): δ -3096. HRMS (FAB): m/z calcd ([M - CH3]+
OM0343972
(35) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. DIRDIF-
97; University of Nijmegen, Nijmegen, The Netherlands, 1997.
(36) Sheldrick, G. M. SHELXL-97; University of Go¨ttingen, Go¨ttin-
gen, Germany, 1997.
(37) Flack, H. D. Acta Crystallogr. 1983, A39, 876-881.
(38) Spek, A. L. J . Appl. Crystallogr. 2003, 36, 7-13.
C
24H23N2Pt) 535.1590, found 535.1579.
Cr ysta l Da ta for 2a : C33H42N2Pt, fw ) 661.78, red block,
0.18 × 0.10 × 0.09 mm3, orthorhombic, P212121 (No. 19), a )