Toward organometallic polymers with high directionality containing bis-ortho-chelating ligands

Article abstract of DOI:10.1021/om000636z

The preparation and structure of the rigid rod-like platinum monoacetylide {Pt}C≡C-4-C₆H₂I-1-((CH₂ NMe₂)₂-2,6) ({Pt} = [Pt(C₆H₃ {Me₂NCH₂}₂-2,6)]) are described. Its oxidative addition to Pd(dba)₂ yields a heterobinuclear {Pt}C≡C{Pd}I complex ({Pd} = [Pd(-4-C₆H₂{Me₂ NCH₂}₂-2,6)]⁺) this provides a new strategy for the controlled and stepwise construction of rigid rod-like metallopolymers.

Full text of DOI:10.1021/om000636z

1024
Organometallics 2001, 20, 1024-1027
Tow a r d Or ga n om eta llic P olym er s w ith High
Dir ection a lity Con ta in in g Bis-or th o-Ch ela tin g Liga n d s
Stephan Back,†,‡ Martin Albrecht,† Anthony L. Spek,§ Gerd Rheinwald,‡
Heinrich Lang,*,‡ and Gerard van Koten*,†
Debye Institute, Department of Metal-Mediated Synthesis, Utrecht University, Padualaan 8,
3584 CH Utrecht, The Netherlands, Technische Universita¨t Chemnitz, Institut fu¨r Chemie,
Lehrstuhl Anorganische Chemie, Strasse der Nationen 62, 09111 Chemnitz, Germany, and
Bijvoet Center for Biomolecular Research, Department of Crystal and Structural Chemistry,
Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
Received J uly 24, 2000
Sch em e 1
Summary: The preparation and structure of the rigid
rod-like platinum monoacetylide {Pt}CtC-4-C6H2I-1-
(CH2NMe2)2-2,6) ({Pt} ) [Pt(C6H3{Me2NCH2}2-2,6)]) are
described. Its oxidative addition to Pd(dba)2 yields a
heterobinuclear {Pt}CtC{Pd}I complex ({Pd} ) [Pd(-
4-C6H2{Me2NCH2}2-2,6)]+); this provides a new strategy
for the controlled and stepwise construction of rigid rod-
like metallopolymers.
In tr od u ction
The chemistry and coordination behavior of metal
complexes of the monoanionic, potentially tridentate
coordinating NCN pincer ligand system (NCN )
[C6H3(CH2NMe2)2-2,6]-)1 and related tridentate phos-
phino or sulfido derivatives have been explored thor-
oughly for a large number of different metal ions.2 This
ligand is able to stabilize unusual oxidation states of
group 10 metal centers, e.g., a Ni(III) center in the
Kharasch addition reaction.3 Moreover, the carbon-to-
metal σ-bond in, for example, [PtCl(NCN)] (complex 1;
abbreviated as {Pt}Cl) has been shown to be stable
toward hydrolysis by water and dilute acids.4
Functionalization of the pincer ligand at the para-
position relative to the metal-bound carbon allows for
the construction of macromolecules with more than one
metal atom.5 In addition, this approach provides access
to hydrogen-bonded molecular structures exhibiting a
directional vector imposed by the ligand architecture
and the metal coordination geometry, e.g., using square-
planar d8 metal centers.6 Such structures (cf. A, Scheme
1) may function as models for electronic conduction
along π-conjugated organometallic chains7 or as com-
plexes with high hyperpolarizabilities,8 since the metal
center is held in direct proximity to the π-conjugated
system owing to the rigid complexation by the NCN
ligand.
Self-condensation, i.e., formal loss of HCl from com-
plexes of type A, can be considered a promising strategy
to construct long-chain molecules (ideally polymers)
which are bound either covalently (type B, Scheme 1)
or via ionic interactions (type C). Related bimetallic
complexes containing nondirectional bis-NCN type link-
ers between the metal centers were demonstrated to
transmit electronic information along their π-conjugated
organic systems.5d,9
(5) (a) Knapen, J . W. J .; van der Made, A. W.; de Wilde, J . C.; van
Leeuwen, P. W. N. M.; Wijkens, P.; Grove, D. M.; van Koten, G. Nature
1994, 372, 659. (b) Davies, P. J .; Grove, D. M.; van Koten, G.
Organometallics 1997, 16, 800. (c) Albrecht, M.; van Koten, G. Adv.
Mater. 1999, 11, 171. (d) Lagunas, M. C.; Gossage, R. A.; Smeets, W.
J . J .; Spek, A. L.; van Koten, G. Eur. J . Inorg. Chem. 1998, 163. (e)
Steenwinkel, P.; Grove, D. M.; Veldman, N.; Spek, A. L.; van Koten,
G. Organometallics 1998, 17, 5647.
(6) (a) Albrecht, M.; Lutz, M.; Spek, A. L.; van Koten, G. Nature
2000, accepted. (b) Davies, P. J .; Veldman, N.; Grove, D. M.; Spek, A.
L.; Lutz, B. T. G.; van Koten, G. Angew. Chem. 1996, 108, 2078; Angew.
Chem., Int. Ed. Engl. 1996, 35, 1956. (c) J ames, S. L.; Verspui, G.;
Spek, A. L.; van Koten, G. Chem. Commun. 1996, 1309.
(7) See for example: (a) Coat, F.; Lapinte, C. Organometallics 1996,
15, 477. (b) Astruc, D. Acc. Chem. Res. 1997, 30, 383. (c) Colbert, M.
C. B.; Lewis, J .; Long, N. J .; Raithby, P. R.; White, A. J . P.; Williams,
D. J . J . Chem. Soc., Dalton Trans. 1997, 99. (d) Brady, M.; Weng, W.;
Zhou, Y.; Seyler, J . W.; Amoroso, A.; Arif, A. M.; Bo¨hme, M.; Frenking,
G.; Gladysz, J . A. J . Am. Chem. Soc. 1997, 119, 775.
* Corresponding authors. E-mail: g.vankoten@chem.uu.nl; heinrich.
lang@chemie.tu-chemnitz.de.
† Debye Institute, Utrecht University.
‡ Universita¨t Chemnitz.
§ Bijvoet Center, Utrecht University.
(1) (a) van Koten, G. Pure Appl. Chem. 1989, 61, 1681. (b) Rietveld,
M. H. P.; Grove, D. M.; van Koten, G. New J . Chem. 1997, 21, 751.
(2) For examples see: (a) Dani, P.; Karlen, T.; Gossage, R. A.;
Smeets, W. J . J .; Spek, A. L.; van Koten, G. J . Am. Chem. Soc. 1997,
119, 11317. (b) Loeb, S. J .; Shimizu, G. K. H.; Wisner, J . H. Organo-
metallics 1998, 17, 2324. (c) Vigalok, A.; Rybtchinski, B.; Shimon, L.
J . W.; Ben-David, Y.; Milstein, D. Organometallics 1999, 18, 895.
(3) See, for example: (a) Gossage, R. A.; van de Kuil, L. A.; van
Koten, G. Acc. Chem. Res. 1998, 31, 423. (b) Kleij, A. W.; Kleijn, H.;
J astrzebski, J . T. B. H.; Spek, A. L.; van Koten, G. Organometallics
1999, 18, 277.
(4) (a) Grove, D. M.; van Koten, G.; Louwen, J . N.; Noltes, J . G.;
Spek, A. L.; Ubbels, H. J . C. J . Am. Chem. Soc. 1982, 104, 6609. (b)
Albrecht, M.; Gossage, R. A.; Spek, A. L.; van Koten, G. Chem. Eur J .
2000, 6, 1431.
(8) (a) Kanis, D. R.; Ratner, M. A.; Marks, T. J . Chem. Rev. 1994,
94, 195. (b) Sponsler, M. B. Organometallics 1995, 14, 1920.
10.1021/om000636z CCC: $20.00 © 2001 American Chemical Society
Publication on Web 02/02/2001

Notes
Organometallics, Vol. 20, No. 5, 2001 1025
Sch em e 2
F igu r e 1. Platinum pincer complex 1.
F igu r e 2. Molecular structure of 3 showing the presence
of hydrogen-bonded molecular dimers in the solid state:
C(14)-H(14) 0.950 Å, H(14)‚‚‚N(2a) 2.401 Å, C(14)‚‚‚N(2a)
3.296(3) Å; C(14)-H(14)‚‚‚N(2a) 156.69°.
Hitherto, only reports dealing with the preparation
of symmetric, nondirectional organometallic polymers
have appeared.10 Moreover, to the best of our knowledge,
direct approaches to well-defined oligomers or polymers
of structural type C are not known. Therefore, we have
developed a stepwise synthesis of such complexes hav-
ing a directionality vector along the organometallic
chain. Preliminary studies showed that the platinum-
acetylide σ-bond in, for example, {Pt}CtCSiMe3 is
easily cleaved in the presence of halide sources, such
as [CuCl]n or [NnBu4]Cl.11 Thus, the well-known Cu(I)-
mediated reactions for the synthesis of Pt(II) acetylides12
are not feasible options for the consecutive construction
of type B structures. Hence, the synthesis of a NCN
ligand system that includes two chemically different
reactive sites was necessary in order to enable the easy
and controlled chemoselective formation of type B
structures.
solution and subsequent reaction with a solution of
K2CO3 in MeOH (Scheme 2). The IR spectrum of 3
showed stretching vibrations (ν
) 3292 cm-1 and
≡CH
νC≡C ) 2106 cm-1) which are typical of phenylacetylene
derivatives.13
Orange-red crystals of 3 were grown by cooling a
n-pentane solution of 3 to -30 °C. The molecular
structure of 3 has been determined by single-crystal
X-ray diffraction analysis.
The CH2NMe2 groups point away from the iodine, and
the nitrogen lone pair of the NMe2 group is directed
toward the acetylenic proton of a coplanar neighboring
molecule of 3 (Figure 2), suggesting intermolecular
C-H‚‚‚N hydrogen bonding (H(14)‚‚‚N(2a) 2.401 Å,
C(14)-H(14)‚‚‚N(2a) 156.7°). The hydrogen-bonded dimer-
ic units display a ladder-type orientation which is
mediated by weak intermolecular halogen-halogen
interactions (I‚‚‚I 3.7273(11) Å). This I‚‚‚I distance is
shorter than the sum of the van der Waals radii (4.3
Å), but substantially longer than the bond distance in
molecular iodine (2.66 Å) and corresponds well with the
average value of the intermolecular I‚‚‚I separation in
crystalline I2.14 The packing motif of compound 3 is
similar to that of 4-X-ethynylbenzene derivatives (X )
Cl, Br, I).15 All other structural details of molecule 3
are similar to those of iodo aryl compounds16 and/or
aromatic acetylenes reported earlier.6,14,17
Resu lts a n d Discu ssion
P r epar ation an d Solid State Str u ctu r e of 4-Eth y-
n y l-2,6-b is (d im e t h y la m in o )m e t h y l-1-io d o b e n -
zen e (3). C6H2I-1-(CH2NMe2)2-2,6-(CtCH)-4 (3) has
been obtained by selective 4-lithiation of C6H3(CH2-
NMe2)2-3,5-(CtCSiMe3)-1 (2), followed by titration of
the resulting lithium derivative with an ethereal iodine
(9) Back, S.; Gossage, R. A.; Lang, H.; van Koten, G. Eur. J . Inorg.
Chem. 2000, 1457.
P r ep a r a tion a n d Str u ctu r a l Ch a r a cter iza tion of
{P t}CtC-4-C6H2I-1-(CH2NMe2)2-2,6 a n d Its Rea c-
(10) See for example: (a) Sonogashira, K.; Kataoka, S.; Takahashi,
S.; Hagihara, N. J . Organomet. Chem. 1978, 160, 319. (b) Takahashi,
S.; Morimoto, H.; Murata, E.; Kataoka, S.; Sonogashira, K.; Hagihara,
N. J . Polymer Sci. 1982, 20, 565. (c) Markwell, R. D.; Butler, I. S.;
Kakkar, A. K.; Khan, M. S.; Al-Zakwani, Z. H.; Lewis, J . Organome-
tallics 1996, 15, 2331. (d) Puddephatt, R. J . Chem. Commun. 1998,
1055.
(13) See for example: (a) Neenan, T. X.; Whitesides, G. M. J . Org.
Chem. 1988, 53, 2489. (b) Takahashi, S.; Kuroyama, Y.; Sonogashira,
K.; Hagihara, N. Synthesis 1980, 627.
(14) Greenwood, N. N.; Earnshaw, A. Chemistry of the Elements;
Pergamon Press: Oxford, England, 1984.
(11) Back, S.; Gossage, R. A.; Lutz, M.; del R´ıo, I.; Spek, A. L.; Lang,
H.; van Koten, G. Organometallics 2000, 19, 3296.
(12) (a) Cross, D. J .; Davidson, M. F. J . Chem. Soc., Dalton Trans.
1986, 1987. (b) Porter, P. L.; Guha, S.; Kang, K.; Frazier, C. C. Polymer
1991, 32, 1756. (c) Osakada, K.; Sakata, R.; Yamamoto, T. Organo-
metallics 1997, 16, 5354.
(15) Weise, H.-C.; Boese, R.; Smith, H. L.; Haley, M. M. Chem.
Commun. 1997, 2403.
(16) Hinchcliff, A.; Munn, R. W.; Pritchard, R. G.; Spicer, C. J . J .
Mol. Struct. 1985, 130, 93.
(17) Garc´ıa, J . G.; Asfaw, B.; Rodriguez, A.; Fronczek, F. Acta
Crystallogr. 1998, C54, 489, and references therein.

1026 Organometallics, Vol. 20, No. 5, 2001
Notes
Sch em e 3
P r epar ation of Bin u clear {P t}CtC{P d}I (5) ({P d}
) [P d (-4-C6H2{CH2NMe2}2-2,6)]+). Treatment of the
19
Pt-acetylide 4 with an equimolar amount of Pd(dba)2
(dba ) dibenzylideneacetone) at 25 °C leads to the
insertion of a Pd atom into the C-I bond (Scheme 3).3
Formation of the heterobimetallic complex {Pt}Ct
C{Pd}I (5) ({Pd} ) [Pd(-4-C6H2{CH2NMe2}2-2,6)]+) is
indicated by 1H NMR spectroscopy, which clearly re-
veals a downfield shift of the resonances of the protons
of the CH2NMe2 groups upon coordination to the Pd(II)
center. The singlets for the NMe2 groups are located at
2.95 ppm in 5 (cf. 2.25 ppm in 4), and the signal of the
benzylic protons is shifted from 3.43 ppm (in 4) to 3.91
ppm. Similar effects are also observed in the 13C{1H}
NMR spectrum of 5. The resonance of C(1) is diagnostic
and shifts from 107.0 ppm (4, bound to iodide) to 160.7
ppm (5, bound to palladium). In the IR, the CtC stretch
vibration (νC≡C ) 2075 cm-1) in 5 is virtually identical
with that observed for 4.
F igu r e 3. ORTEP view (50% probability) of the platinum
acetylide 4 with the adopted numbering scheme. Selected
bond distances (Å) and angles (deg): Pt-C(1) 1.942(7), Pt-
C(13) 2.061(7), Pt-N(1) 2.077(5), Pt-N(2) 2.088(5), C(13)-
C(14) 1.195(10), C(14)-C(15) 1.438(9), C(18)-I 2.118(7);
C(1)-Pt-C(13) 178.3(3), C(1)-Pt-N(1) 81.6(3), C(1)-Pt-
N(2) 80.9(3), N(1)-Pt-N(2) 162.5(2), N(1)-Pt-C(13) 96.8-
(2), N(2)-Pt-C(13) 100.7(3), Pt-C(13)-C(14) 170.6(7),
C(13)-C(14)-C(15) 175.5(8).
tion w ith P d (d ba )2. Selective deprotonation of the
acetylenic moiety in the ligand precursor 3 without
affecting the carbon-halide bond was accomplished by
using n-BuLi at -78 °C (Scheme 2). The lithium
acetylide was treated in situ with platinum complex
{Pt}Cl (1), thus affording the rigid rod-like platinum
acetylide [{Pt}CtC-4-C6H2I-1-(CH2NMe2)2-2,6] (4). All
spectroscopic data (IR, 1H NMR, 13C{1H} NMR) of 4 are
in accordance with the proposed structure and compare
well with the values recently reported for similar
platinum-bound acetylides.12
Con clu sion s
The NCN-type ligand C6H2I-1-(CH2NMe2)2-2,6-(Ct
CH)-4 (3), containing two different reactive sites, has
been synthesized. In the solid state, this molecule forms
a â-type network stabilized by I‚‚‚I interactions and
C-H‚‚‚N hydrogen bonding. The attachment of 3 to a
{Pt} terminal unit leads to the formation of the rigid
rod-like Pt-acetylide 4. The crystal structure of this free
NCN-Pt monoacetylide combines features of both NCN-
Pt complexes as well as of other Pt-acetylide systems.
The presence of a Pt center does not change the
structural arrangement of the iodo-NCN fragment.
Further, oxidative addition of 4 to a Pd(0) moiety yields
the heterobinuclear Pt-Pd complex 5 and thus provides
a good strategy for the controlled and stepwise con-
struction of rigid rod-like metallopolymers.
By cooling a toluene solution of 4 to -30 °C, single
crystals were obtained which were suitable for an X-ray
crystal structure determination. The solid state struc-
ture of 4 is given in Figure 3. The platinum center is
held in a distorted square-planar environment with the
σ-acetylide ligand in a position trans to Cipso of the η3-
N,C,N bonded aryldiamine ligand. This coordination
geometry is typical for molecules containing a NCN-
Pt entity.4,6 The Pt-C(13) bond length of 2.061(7) Å is
within the range of reported Pt σ-acetylide distances.18
The CtC triple bond (C(13)-C(14) 1.195(10) Å) is
slightly longer than in the nonmetalated acetylene 3
(1.183(3) Å), which corresponds with a shift of the νC≡C
stretching vibration band to lower wavenumbers (cf.
Experimental Section). As expected, the π-conjugated
organometallic system in 4 is nearly linearly arranged
and therefore represents a rigid rod-like building block
for the preparation of polymeric materials containing
transition metals interconnected by directional linkers.
The aromatic rings are tilted by only 12.9(3)° relative
to each other, which is essential for electronic com-
munication and a direct consequence of the acetylenic
spacer. In bisaryl platinum systems, which lack such a
C2 fragment, this angle is typically larger than 75° and,
therefore, any π-conjugation is interrupted. Interest-
Exp er im en ta l Section
Gen er a l Com m en ts. All reactions were carried out under
an atmosphere of dry nitrogen using standard Schlenk tech-
niques. Tetrahydrofuran (THF) and diethyl ether (Et2O) were
purified by distillation from sodium/benzophenone ketyl; n-
pentane was purified by distillation from CaH2. All NMR
spectra were recorded at 298 K (1H NMR at 300 MHz, 13C-
{1H} NMR at 75 MHz). Chemical shifts (δ) are reported in ppm
(J in Hz) and referenced to SiMe4. FAB mass spectra were
recorded at the Department of Mass Spectrometry, Bijvoet
Center, Utrecht University. Melting points are uncorrected.
Microanalyses were performed by H. Kolbe, Mikroanalytisches
Laboratorium, Mu¨lheim/Ruhr, Germany.
2
ingly, the Csp-Csp and C-I bond lengths (C(14)-C(15)
1.438(10) Å, C(18)-I 2.118(7) Å) are both very close to
the values found in the metal-free acetylene 3, suggest-
ing a minimal influence of the platinum center on the
carbon-iodide bond.
(18) See for example: (a) Sebald, A.; Stader, C.; Wrackmeyer, B. J .
Organomet. Chem. 1986, 311, 233. (b) Kowalski, M. H.; Arif, A. M.;
Stang, P. J . Organometallics 1988, 7, 1227.
(19) Rettig, M. F.; Maitlis, P. M. Inorg. Synth. 1977, 17, 134.

Notes
Organometallics, Vol. 20, No. 5, 2001 1027
The starting materials {Pt}Cl (1),4 Pd(dba)2,19 and C6H3-
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p lexes 3
a n d 4
(CH2NMe2)2-2,6-(CtCSiMe3)-4 (2)6 were prepared according
to published procedures. All other chemicals were obtained
commercially and used as received.
3
4
empirical formula
fw
C
14H19IN2
C26H34IN4Pt
727.59
C6H2I-1-(CH2NMe2)2-2,6-(CtCH)-4 (3). To a n-pentane
solution (150 mL) of 2 (2.17 g, 7.5 mmol) was added n-BuLi
(1.6 molar in hexane, 6.1 mL, 9.8 mmol) at -78 °C. After
gradual warming to 25 °C (12 h), the reaction mixture was
concentrated and the residue dissolved in Et2O (20 mL). An
ethereal solution of I2 (2.5 g, 9.8 mmol in 100 mL) was slowly
added until a brown color persisted. The reaction mixture was
extracted with aqueous HCl (10%, 4 × 10 mL). After washing
with Et2O (3 × 50 mL), the combined aqueous phases were
basified to pH > 12 using a 5% NaOH solution and extracted
with Et2O (3 × 50 mL). The combined ethereal extracts were
dried over MgSO4 and filtered, and the Et2O was evaporated
in vacuo to yield a brown oil. This was transferred to a solution
of K2CO3 in MeOH (1.0 g, 7.2 mmol, 100 mL). After stirring
for 5 h at 25 °C, all volatiles were removed in vacuo, and the
residue was extracted with n-pentane (3 × 50 mL). Evapora-
tion of the combined extracts gave 3 (2.18 g, 85% yield based
on 2) as a brown oil, which solidified upon standing.
342.21
diffractometer
T/K
Enraf Nonius CAD4-T Bruker SMART CCD
150
173
cryst syst
space group
cryst size/mm
cryst color
unit cell dimens
a/Å
monoclinic
C2/c (No. 15)
0.63 × 0.38 × 0.38
orange-red
monoclinic
P2l/c (No. 14)
0.10 × 0.10 × 0.08
colorless
25.6646(10)
5.8561(17)
22.8571(18)
121.537(5)
2927.9(9)
8
12.2857(7)
11.7091(6)
19.5948(10)
105.235(1)
2719.7(3)
4
1.777
6.314
PLATON (DELABS)
0.45-0.65
0.68
b/Å
c/Å
â/deg
V/Å3
Z
D
calc/g cm-3
1.553
µ/mm-1 (Mo KR) 2.170
abs corr
PLATON (ABSPSI)
0.86-0.98
0.65
transmn range
(sin θ/λ)max/Å-1
no. of reflns obsd, 8450, 3382, 3011
measd, unique
11597, 6943, 4301
Mp: 52 °C. IR (NaCl): 2106 cm-1 (s; νC≡C), 3292 cm-1 (s;
1
ν
≡CH). H NMR (CDCl3): δ 2.31 (s, 12 H, NMe2), 3.09 (s, 1 H,
Rint
0.035
0.054
tCH), 3.49 (s, 4 H, CH2), 7.41 (s, 2 H, Caryl-H). 13C{1H} NMR
(CDCl3): δ 45.5 (NMe2), 68.8 (CH2), 77.8 (CtCH), 83.0 (Ct
CH), 121.5 (Caryl), 131.5 (Caryl), 132.1 (Caryl-H), 142.3 (Caryl).
FAB-MS: m/z (rel int) 343 (100) {[M + H]+}, 341 (40) {[M -
H]+}, 215 (40) {[M + H]+ - HI}, 128 (30) {[HI]+} 58 (50)
{[C3H8N]+}. Anal. Calcd for C14H19IN4 (342.22): C, 49.14; H,
5.60; N, 8.11. Found: C, 49.24; H, 5.63; N, 8.11.
no. of params
R1 obsd/all
154
0.0219/0.0263
297
0.0451/0.1002
a
reflns
b
wR2 all reflns
0.0543
0.0826
S
1.033
0.915
resid density/
-0.95 < 0.70
-2.33 < 1.15
e Å-3
a
b
2
{P t}CtCC6H2I-4-(CH2NMe2)2-3,5 (4). To a Et2O solution
(150 mL) of LiCtCC6H2I-4-(CH2NMe2)2-3,5 (350 mg, 1.0 mmol)
was added 1 (430 mg, 1.0 mmol) at -78 °C. After gradual
warming to 25 °C and stirring for 24 h, all volatile materials
were removed in vacuo. The resulting residue was extracted
with n-pentane (5 × 40 mL), and the combined organic pahses
were evaporated to dryness, affording 4 (290 mg, 40% yield
based on 1) as a brown solid.
R1 ) ∑||Fo| - |Fc||/∑|Fo|, for all I > 2σ(I). wR2 ) [∑[w(Fo
-
Fc2)2]/∑[w(Fo2)2]]1/2
.
Sin gle-Cr ysta l X-r a y Diffr a ction s. X-ray data were col-
lected on an Enraf-Nonius CAD4-T with rotating anode (3) or
on a Bruker SMART CCD area detector (4), using monochro-
mated Mo KR radiation (λ ) 0.71073 Å). Crystal data and
details on data collection and refinement are given in Table
1. The structures were solved with Patterson methods (DIRDIF-
9720) and refined against F2 of all reflections (SHELXL-9721).
Non-hydrogen atoms were refined freely with anisotropic dis-
placement parameters, and hydrogen atoms were refined at
calculated positions riding on their carrier atoms. Weights
were introduced in the last refinement cycles. Neutral atomic
scattering factors and anomalous dispersion corrections were
taken from the International Tables of Crystallography. All
other calculations, graphical illustrations, and checking for
higher symmetry were performed with the PLATON22 package.
1
Mp: 140 °C (dec). IR (KBr): 2076 cm-1 (s, νC≡C). H NMR
3
(CDCl3): δ 2.25 (s, 12 H, NMe2), 3.21 (s, J HPt ) 39.8 Hz, 12
H, NMe2), 3.43 (s, 4 H, CH2), 4.11 (s, 3J HPt ) 48 Hz, 4 H, CH2),
6.8-7.0 (m, 3 H, Caryl-H), 6.89 (s, 2 H, Caryl-H). 13C{1H} NMR
(CDCl3): δ 45.6 (NMe2), 56.0 (NMe2), 69.1 (CH2), 80.0 (CH2),
103.3 (PtCtC), 107.0 (Caryl), 118.6 (Caryl-H), 126.6 (Caryl), 128.0
(Caryl-H), 132.4 (Caryl-H), 138.2 (PtCtC), 141.1 (Caryl), 146.1
(Caryl), 166.6 (Caryl). FAB-MS: m/z (rel int) 728 (20) {[M + H]+}
727 (15) M+, 385 (90) {[C12H19N2Pt]+}, 343 (10) {[C14H16IN2]+}.
Anal. Calcd for C26H37IN4Pt (727.60): C, 42.92; H, 5.13; N,
7.70. Found: C, 42.68; H, 5.26; N, 7.60.
{P t}CtC{P d }I (5). To a solution of 4 (70 mg, 0.1 mmol) in
toluene (30 mL) was added Pd(dba)2 (55 mg, 0.1 mmol) at 25
°C. After stirring for 48 h, all volatile materials were evapo-
rated. The residue was successively washed with n-pentane
(2 × 5 mL) and Et2O (3 × 10 mL) and extracted with CH2Cl2
(5 × 10 mL). The combined CH2Cl2 extracts were filtered
through a pad of Celite and concentrated to 5 mL. Addition of
n-pentane (30 mL) resulted in a brownish precipitate. Drying
in vacuo gave 5 (35 mg, 40% based on 4).
Ack n ow led gm en t. The authors are grateful to the
Volkswagenstiftung and Utrecht University for financial
support (1.5 year stay of S.B.). We would also like to
thank Dr. I. del R´ıo, Dr. R. A. Gossage, and Dr. J .
Boersma for valuable discussions.
Su p p or tin g In for m a tion Ava ila ble: Full listing of crys-
tallographic details. This material is available free of charge
via the Internet at http://pubs.acs.org.
Mp: >200 °C. IR (KBr): 2075 cm-1 (s, νC≡C). 1H NMR (CD2-
3
Cl2): δ 2.95 (s, 12 H, NMe2), 3.18 (s, J HPt ) 38.2 Hz, 12 H,
OM000636Z
3
NMe2), 3.91 (s, 4 H, CH2), 4.09 (s, J HPt ) 46.5 Hz, 4 H, CH2),
6.8-7.0 (m, 3 H, Caryl-H), 7.06 (s, 2 H, Caryl-H). 13C{1H} NMR
(CD2Cl2): δ 54.1 (NMe2), 55.4 (NMe2), 66.9 (CH2), 80.0 (CH2),
103.5 (PtCtC), 117.8 (Caryl-H), 124.7 (Caryl), 127.5 (Caryl-H),
131.4 (Caryl-H), 137.4 (PtCtC), 142.1 (Caryl), 146.1 (Caryl), 160.7
(Caryl), 166.6 (Caryl). FAB-MS: m/z (rel int) 833 (10) M+, 448
(20) {[C14H18IN2Pd]+}, 385 (100) {[C12H19N2Pt]+}. Anal. Calcd
(20) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J . M. M.; Smykalla, C. The
DIRDIF Program System; Technical Report of the Crystallography
Laboratory; University of Nijmegen: Nijmegen, The Netherlands,
1997.
(21) Sheldrick, G. M. SHELXL-97, Program for Crystal Structure
Refinement; University of Go¨ttingen: Go¨ttingen, Germany, 1997.
(22) Spek, A. L. PLATON, A Multipurpose Crystallographic Tool;
Utrecht University: Utrecht, The Netherlands, 2000.
for
C26H37IN4PdPt (834.02): C, 37.44; H, 4.47; N, 6.72.
Found: C, 36.98; H, 4.10; N, 6.38.