Monoarylplatinum(II) complexes with a 2-phenylpyridyl ligand and coordinated solvent, [Pt(Ar)(Phpy)(solv)] (Phpy = 2-phenylpyridyl; solv = NCCH3, dmso). Preparation from [Pt(Ar)2(solv) 2], structures, and chemical properties

Article abstract of DOI:10.1021/om061137m

Diarylplatinum(II) complexes, [Pt(Ar)₂(dmso)₂] (Ar = C₆H₃Me₂-3,5 (1a), C₆H ₃(CF₃)₂-3,5 (1b), Ph (1c); dmso = dimethyl sulfoxide) and [Pt{C₆H₃(CF₃) ₂-3,5}₂(NCCH₃)₂] (2b), were prepared and fully characterized. Heating mixtures of 2-phenylpyridine (PhpyH) with the complexes in solution at 50°C caused coordination of PhpyH and its cyclometalation accompanied by elimination of arene to produce monoarylplatinum(II) complexes with a solvent ligand, [Pt(Ar)(Phpy)(dmso)] (Ar = C₆H₃Me₂-3,5 (3a), C₆H ₃(CF₃)₂-3,5 (3b), Ph (3c)) and [Pt{C ₆H₃(CF₃)₂-3,5}(Phpy)(NCCH ₃)] (4b). The rate of the reactions decreased in the order 1a > 1c > 2b > 1b. Crystal structures of 3a,c and ¹H NMR spectra of the complexes showed that the aryl ligand and phenyl group of the Phpy ligand occupied cis positions. A diarylplatinum complex with a monodentate phenylpyridyl ligand, [Pt(C₆H₃Me₂-3,5) ₂(CF₃PhpyH)(dmso)] (5), was isolated and characterized using X-ray crystallography. The neutral arylplatinum(II) complex 4b underwent exchange of the acetonitrile ligand more easily than the cationic complex, [Pt{C₆H₃(CF₃)₂-3,5}(bpy)-(NCCH ₃)]⁺, because of the C-bonded phenyl group of the Phpy ligand had a greater trans effect than the N-bonded pyridyl group of bpy. Oxidative addition of I₂ to 3a,b and 4b readily gave Pt(IV) dimeric complexes with bridging iodo ligands, [(Pt(Ar)(Phpy)I)₂(μ-I) ₂] (Ar = C₆H₃Me₂-3,5 (7a), C ₆H₃(CF₃)₂-3,5 (7b)). The dimeric structure of 7b was confirmed using X-ray crystallography.

Full text of DOI:10.1021/om061137m

Organometallics 2007, 26, 2383-2391
2383
Monoarylplatinum(II) Complexes with a 2-Phenylpyridyl Ligand
and Coordinated Solvent, [Pt(Ar)(Phpy)(solv)] (Phpy )
2-phenylpyridyl; solv ) NCCH3, dmso). Preparation from
[Pt(Ar)2(solv)2], Structures, and Chemical Properties
Takeyoshi Yagyu,* Jun-ichi Ohashi, and Masunobu Maeda
Department of Materials Science and Engineering, Graduate School of Engineering, Nagoya Institute of
Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan
ReceiVed December 18, 2006
Diarylplatinum(II) complexes, [Pt(Ar)2(dmso)2] (Ar ) C6H3Me2-3,5 (1a), C6H3(CF3)2-3,5 (1b), Ph (1c);
dmso ) dimethyl sulfoxide) and [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b), were prepared and fully
characterized. Heating mixtures of 2-phenylpyridine (PhpyH) with the complexes in solution at 50 °C
caused coordination of PhpyH and its cyclometalation accompanied by elimination of arene to produce
monoarylplatinum(II) complexes with a solvent ligand, [Pt(Ar)(Phpy)(dmso)] (Ar ) C6H3Me2-3,5 (3a),
C6H3(CF3)2-3,5 (3b), Ph (3c)) and [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)] (4b). The rate of the reactions
decreased in the order 1a > 1c > 2b > 1b. Crystal structures of 3a,c and 1H NMR spectra of the complexes
showed that the aryl ligand and phenyl group of the Phpy ligand occupied cis positions. A diarylplatinum
complex with a monodentate phenylpyridyl ligand, [Pt(C6H3Me2-3,5)2(CF3PhpyH)(dmso)] (5), was isolated
and characterized using X-ray crystallography. The neutral arylplatinum(II) complex 4b underwent
exchange of the acetonitrile ligand more easily than the cationic complex, [Pt{C6H3(CF3)2-3,5}(bpy)-
(NCCH3)]+, because of the C-bonded phenyl group of the Phpy ligand had a greater trans effect than the
N-bonded pyridyl group of bpy. Oxidative addition of I2 to 3a,b and 4b readily gave Pt(IV) dimeric
complexes with bridging iodo ligands, [(Pt(Ar)(Phpy)I)2(µ-I)2] (Ar ) C6H3Me2-3,5 (7a), C6H3(CF3)2-3,5
(7b)). The dimeric structure of 7b was confirmed using X-ray crystallography.
(CO)(mts) (mts ) methylthiosalicylate),5 PtCl(thpy)(CO),6 and
Pt(thpy)(acac),7 were prepared. Then their optical properties
were studied. Ligands of this type perform as monoanionic
bidentate ligands via coordination of nitrogen and cyclometa-
lation of the aryl or thienyl group.
Monoarylplatinum complexes having neutral chelating ligands,
such as diene and diamines and labile solvent ligand, contain a
cationic metal center. These complexes reportedly show various
reactivities such as insertion of unsaturated molecules into the
Pt-Ar bond,8,9 oxidative addition,9 transmetalation of the aryl
ligand,10 and C-H activation.11 Monoarylplatinum complexes
with a solvent ligand and chelating (2-pyridyl)aryl ligand have
a neutral Pt center and exhibit chemical properties different from
those with diene and diamine ligands. Such neutral Pt complexes
with a solvent ligand, however, have been reported only rarely.12
Introduction
Organoplatinum complexes exhibit various reactivities toward
fundamental reactions such as C-H activation,1 oxidative
addition,2 and reductive elimination,3 depending on the valence
of the metal centers and on the supporting ligands. Recently,
2-phenylpyridyl (Phpy) ligands have attracted attention because
their Ir complexes show good fluorescent properties.4 Platinum
complexes with the 2-(2′-thienyl)pyridyl (thpy) ligand, Pt(thpy)-
* To whom correspondence should be addressed. E-mail: yagyu@
nitech.ac.jp.
(1) (a) Lersch, M.; Tilset, M. Chem. ReV. 2005, 105, 2471 and references
therein. (b) Zhang, F.; Kirby, C. W.; Hairsine, D. W.; Jennings, M. C.;
Puddephatt, R. J. J. Am. Chem. Soc. 2005, 127, 14196. (c) Driver, T. G.;
Day, M. W.; Labinger, J. A.; Bercaw, J. E. Organometallics 2005, 24, 3644.
(d) Crespo, M.; Granell, J.; Font-Brad´ıa, M.; Solans, X. J. Organomet. Chem.
2004, 689, 3088. (e) Heyduk, A. F.; Driver, T. G.; Labinger, J. A.; Bercaw,
J. E. J. Am. Chem. Soc. 2004, 126, 15034.
(2) (a) Zhang, F.; Broczkowski, M. E.; Jennings, M. C.; Puddephatt, R.
J. Can. J. Chem. 2005, 83, 595. (b) Yahav, A.; Goldberg, I.; Vigalok, A.
Organometallics 2005, 24, 5654. (c) Westra, A. N.; Bourne, S. A.;
Esterhuysen, C.; Koch, K. R. Dalton Trans. 2005, 2162. (d) Bosque, R.;
Crespo, M.; Evangelio, E.; Font-Bardia, M.; Solans, X. J. Organomet. Chem.
2005, 690, 2062. (e) Albano, V. G.; De Felice, V.; Monari, M.; Roviello,
G.; Ruffo, F. Eur. J. Inorg. Chem. 2005, 416.
In this study, we attempted to obtain solvated diarylplatinum
complexes using a coordinating solvent by direct substitution
(5) Kovelenov, Y. A.; Blake, A. J.; George, M. W.; Matousek, P.;
Mel’nikov, M. Ya.; Parker, A. W.; Sun, X.-Z.; Towrie, M.; Weinstein, J.
A. Dalton Trans. 2005, 2092.
(6) Yersin, H.; Donges, D.; Humbs, W.; Strasser, J.; Sitters, R.; Glasbeek,
M. Inorg. Chem. 2002, 41, 4915.
(3) (a) Procelewska, J.; Zahl, A.; Liehr, G.; van Eldik, R.; Smythe, N.
A. Williams, B. S.; Goldberg, K. I. Inorg. Chem. 2005, 44, 7732. (b) Ozawa,
F.; Tani, T.; Katayama, H. Organometallics 2005, 24, 2511. (c) Shekhar,
S.; Hartwig, J. F. J. Am. Chem. Soc. 2004, 126, 13016. (d) Crumpton-
Bregel, D. M.; Goldberg, K. I. J. Am. Chem. Soc. 2003, 125, 9442.
(4) (a) Kim, J. I.; Shin, I.; Kim, H.; Lee, J. J. Am. Chem. Soc. 2005,
127, 1614. (b) Jung, S.; Kang, Y.; Kim, H.; Kim, Y.; Lee, C.; Kim, J.; Lee,
S.; Kwon, S. Eur. J. Inorg. Chem. 2004, 17, 3415. (c) Kapturkiewicz, A.;
Angulo, G. Dalton Trans. 2003, 3907. (d) Tamayo, A. B.; Alleyne, B. D.;
Djurovich, P. I.; Lamansky, S.; Tsyba, I.; Ho, N. N.; Bau, R.; Thompson,
M. E. J. Am. Chem. Soc. 2003, 125, 7377.
(7) Brooks, J.; Babayan, Y.; Lamansky, S.; Djurovich, P. I.; Tsyba, I.;
Bau, R.; Thompson, M. E. Inorg. Chem. 2002, 41, 3055.
(8) (a) De Felice, V.; De Renzi, A.; Fraldi, N.; Roviello, G.; Tuzi, A. J.
Organomet. Chem. 2005, 690, 2035. (b) Cucciolito, M. E.; De Renzi, A.;
Orabona, I.; Ruffo, F.; Tesauro, D. J. Chem. Soc., Dalton Trans. 1998,
1675. (c) De Felice, V.; De Renzi, A.; Ferrara, M. L.; Panunzi, A. J.
Organomet. Chem. 1996, 513, 97.
(9) Yagyu, T.; Suzaki, Y.; Osakada, K. Organometallics 2002, 21, 2088.
(10) Suzaki, Y.; Osakada, K. Organometallics 2004, 23, 5081.
(11) Suzaki, Y.; Yagyu, T.; Yamamura, Y.; Mori, A.; Osakada, K.
Organometallics 2002, 21, 5254.
10.1021/om061137m CCC: $37.00 © 2007 American Chemical Society
Publication on Web 03/24/2007

2384 Organometallics, Vol. 26, No. 9, 2007
Yagyu et al.
Figure 1. ORTEP drawings of (a) 1a and (b) 1b (50% probability).
Table 1. Selected Bond Distances (Å) and Angles (deg) for
1a,b and 5
of cod in [PtAr2(cod)] with the solvent molecules. We have
therefore chosen acetonitrile as the solvent molecule and
investigated it for some aryl groups. Reactivities of obtained
complexes for cyclometalation with 2-phenylpyridine, which
involves oxidative addition and reductive elimination, have been
discussed on the basis of the nature of the coordinating solvent
and aryl group. In addition, exchange reactions of the coordinat-
ing acetonitrile and oxidative addition of I2 to cyclometalated
complexes have been studied.
1a
1b
5
Pt1-S1
Pt1-S2
Pt1-C1
Pt1-C9
Pt1-N1
2.316(2)
2.332(2)
2.025(8)
2.034(8)
2.325(2)
2.310(2)
2.020(6)
2.033(6)
2.287(1)
2.033(4)
2.016(4)
2.143(4)
S1-Pt1-S2
S1-Pt1-C1
S1-Pt1-C9
S2-Pt1-C1
S2-Pt1-C9
C1-Pt1-C9
S1-Pt1-N1
N1-Pt1-C1
N1-Pt1-C9
90.73(7)
175.9(2)
91.2(2)
93.1(2)
176.2(2)
84.9(3)
95.58(6)
172.8(2)
91.4(2)
90.2(2)
172.9(2)
83.0(3)
178.6(1)
91.3(1)
Results and Discussion
89.5(2)
88.84(10)
90.4(1)
Preparation and Characterization of Solvated Diarylplati-
num(II) Complexes. The preparation of [PtPh2(dmso)2] was
reported by Lanza et al.13 Analogous reactions of dmso with
PtAr2(cod) produce [PtAr2(dmso)2] (Ar ) C6H3Me2-3,5 (1a),
C6H3(CF3)2-3,5 (1b)) as shown in eq 1. The complex [PtPh2-
178.0(2)
Figure 1 shows crystal structures for 1a,b. The complexes
have distorted-square-planar platinum centers that are bonded
to two aryl groups and two S-coordinated dmso molecules with
a cis configuration. Selected bond lengths and angles are given
in Table 1. The Pt-C bond distances are similar among 1a
(2.025(8) and 2.034(8) Å), 1b (2.020(6) and 2.033(6) Å), and
1c (2.043(5) and 2.046(6) Å).14 The Pt-S bond lengths (2.316-
(2) and 2.332(2) Å for 1a and 2.325(2) and 2.310(2) Å for 1b)
are longer than those of [PtCl2(dmso)2] (2.244(2) and 2.299(2)
Å)15 because of a strong trans influence of the aryl ligands. The
1H NMR spectra of the complexes in CDCl3 exhibit signals of
para and ortho hydrogens of aryl ligands at δ 6.46 and 6.93
(1a), at δ 6.81 and 7.29 (1c), and at δ 7.41 and 7.77 (1b). The
peak positions are influenced by the electron-donating Me
groups and electron-withdrawing CF3 groups of the aryl ligand.
Positions of CH3 hydrogens of the dmso ligand are also shifted
to lower magnetic field positions in the order 1a (δ 2.78), 1c
(dmso)2] (1c) was also used in the following study to compare
the reactivities of the complexes depending on the coordinating
solvent and the aryl ligands.
Heating an acetonitrile solution of [Pt{C6H3(CF3)2-3,5}2(cod)]
at 50 °C forms [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b) in moder-
ate yield (59.0%). Isolated 2b is stable both in the solid state
and in solution (acetone or acetonitrile) for at least 1 week in
the air. However, the reactions with [Pt(C6H3Me2-3,5)2(cod)]
and with [PtPh2(cod)] give only small amounts of complexes
1
(δ 2.82), and 1b (δ 2.90). The H-195Pt coupling constants
observed for the signals of the ortho hydrogens (70-71 Hz)
and hydrogens of dmso (14-15 Hz) do not vary in the
complexes. The latter coupling constants are reasonable for dmso
molecules that are S-coordinated to Pt. Furthermore, 2b is
characterized as the cis complex on the basis of the similarity
of the 1H-195Pt coupling constant between the ortho hydrogen
and 195Pt (78 Hz) with those of 1a-c.
Reaction of PhpyH with 1a-c and 2b Leading to Cyclo-
metalation. [PtAr2(dmso)2] was reported by Lanza et al. to
undergo substitution of the dmso ligands.13 The reaction of
2-phenylpyridine (PhpyH) with these complexes results in
1
with NCCH3 ligands, which were confirmed using H NMR
spectroscopy in CD3CN. Attempts at isolation have failed,
probably because of decomposition that releases the correspond-
ing biaryl.
(12) (a) Zucca, A.; Cinellu, M. A.; Minghetti, G.; Stoccoro, S.;
Manassero, M. Eur. J. Inorg. Chem. 2004, 4484. (b) Minghetti, G.; Stoccoro,
S.; Cinellu, M. A.; Soro, B.; Zucca, A. Organometallics 2003, 22, 4770.
(c) Zucca, A.; Doppiu, A.; Cinellu, M. A.; Stoccoro, S.; Minghetti, G.;
Manassero, M. Organometallics 2002, 21, 783.
(13) Lanza, S.; Minniti, D.; Moore, P.; Sachinidis, J.; Romeo, R.; Tobe,
M. L. Inorg. Chem. 1984, 23, 4428.
(14) Bardi, R.; Del Pra, A.; Piazzesi, A. M.; Trozzi, M. Cryst. Struct.
Commun. 1981, 10, 301.
(15) Melanson, R.; Rochon, F. D. Can. J. Chem. 1975, 53, 2371.

Monoarylplatinum(II) Complexes
Organometallics, Vol. 26, No. 9, 2007 2385
Figure 2. ORTEP drawings of (a) 3a and (b) 3c (50% probability).
Table 2. Selected Bond Distances (Å) and Angles (deg) for
3a,c
3a
3c
3a
3c
Pt1-S1
Pt1-N1
Pt1-C1
2.299(4) 2.302(2) Pt1-C9
2.02(2)
3.10(2)
2.019(9)
2.12(1)
2.03(2)
2.115(7) O1-C19
2.031(9) O1-C17
3.09(1)
S1-Pt1-N1 99.5(4)
S1-Pt1-C1 88.3(5)
99.5(2)
89.0(3)
N1-Pt1-C1 172.2(6) 171.3(3)
N1-Pt1-C9 80.5(6)
79.6(3)
91.9(3)
S1-Pt1-C9 176.6(4) 178.5(2) C1-Pt1-C9 91.8(7)
Figure 3. 1H NMR spectra (300 MHz, acetone-d6) of (a) 1a, (b)
of the solution immediately after mixing 1a and PhpyH at room
temperature, and (c) of the solution in (b) 10 h after reaction at 50
°C. Signals with asterisks are assigned to intermediate complex A.
coordination of the ligand with the nitrogen atom of the pyridyl
group and the subsequent cyclometalation of the ligand, similar
to the reaction of PhpyH with other transition-metal complexes.
Few studies of such cyclometalation involving C-H bond
activation and formation of a new metal-carbon bond have been
reported for the preparation of arylplatinum complexes with
solvent ligands.12
(8)-1.993(7) Å).16 The Pt-N bonds of 3a (2.12(1) Å) and 3c
(2.115(7) Å) are similar to that of [PtCl(Phpy)(CO)] (2.114-
(19) Å),16a in which a nitrogen atom is trans to the CO ligand.
These distances are longer than those of other complexes having
the C-N cyclometalated ligand (2.011(6)-2.016(5) Å).16 The
strong trans influence of the aryl ligands of 3a,c and of the CO
ligand of [PtCl(Phpy)(CO)] lengthens the Pt-N bond trans to
the ligand. The N-Pt-C bite angles of the Phpy ligands of 3a
(80.5(6)°) and 3c (79.6(3)°) are smaller than for the other
cyclometalated complexes (80.7(2)-82.1(3)°)16 because of the
elongation of Pt-C and Pt-N bond lengths for 3a,c.
Adding PhpyH to acetone solutions of 1a-c and 2b and
heating the solutions to 50 °C afford the monoarylplatinum
complexes [Pt(Ar)(Phpy)(dmso)] (Ar ) C6H3Me2-3,5 (3a),
C6H3(CF3)2-3,5 (3b), Ph (3c)) and [Pt{C6H3(CF3)2-3,5}(Phpy)-
(NCCH3)] (4b), as shown in eq 2.
1
The H NMR spectra of 3a,b in acetone-d6 show signals of
para and ortho hydrogens of the aryl ligand at δ 6.59 and 7.10
(3a) and at δ 7.62 and 8.15 (3b). Higher magnetic field positions
for the former complex than for the latter are ascribed to the
difference in the electron-donating capabilities of the substitu-
ents, CH3 and CF3, of the aryl ligands. The 1H-195Pt coupling
1
constants observed in the H NMR signals of ortho hydrogens
and methyl protons of dmso of 3a (70 and 17 Hz) are similar
to those for 3b (69 and 16 Hz). The signals of H6 of Phpy of
3a (δ 9.70) and 3b (δ 9.71) are shifted downfield compared to
that of 4b (δ 8.87). Crystal structures of the complexes show a
short contact between the O atom of dmso and the CH group
adjacent to the N atom of Phpy (3a, O1-C19 ) 3.10(2) Å; 3c,
O1-C17 ) 3.09(1) Å). The presence of a C-H‚‚‚O interaction
1
is suggested in the solid state. The downfield shift of the H
NMR signal of that hydrogen described above is attributed to
a similar intramolecular interaction in solution.
The complexes were characterized by X-ray crystallography
and NMR spectroscopy. Figure 2 shows the crystal structures
of 3a,c. Both complexes have distorted-square-planar platinum
centers that are bonded to an aryl group, to the C-N bidentate
deprotonated 2-phenylpyridine, and to S-coordinated dmso.
Selected bond lengths and angles are given in Table 2. Distances
of the Pt-aryl and Pt-S bonds of 3a,c are comparable to those
for 1a,c,14 whereas Pt-C bond lengths of the Phpy ligand (2.02-
(2) Å for 3a and 2.019(9) Å for 3c) are slightly longer than
those of analogous cyclometalated platinum complexes (1.975-
Reactions of PhpyH with 1a-c and 2b at 50 °C were
monitored using 1H NMR spectroscopy in acetone-d6. Figure 3
summarizes the change of spectra caused by the reaction of
PhpyH with 1a. The spectrum of an equimolar mixture of 1a
and PhpyH at room temperature (Figure 3b) shows the signal
for the hydrogen of the pyridine ring at δ 9.16. The signal is at
(16) (a) Mdleleni, M. M.; Bridgewater, J. S.; Watts, R. J.; Ford, P. C.
Inorg. Chem. 1995, 34, 2334. (b) Kvam, P.-I.; Engebretsen, T.; Maartmann-
Moe, K.; Songstad, J. Acta Chem. Scand. 1996, 50, 107.

2386 Organometallics, Vol. 26, No. 9, 2007
Yagyu et al.
Scheme 1
a much lower field than the corresponding hydrogen of the free
ligand, PhpyH (δ 8.68), with accompanying 195Pt satellite signals
(JPt-H ) 20 Hz). Two signals attributable to para hydrogens of
the 3,5-dimethylphenyl groups are observed at δ 6.26 and 6.29,
indicating the nonequivalence of the two aryl ligands bonded
to Pt. Nonequivalent meta hydrogens (δ 2.01 and 2.07) of the
aryl group are also observed. The signals attributable to liberated
and coordinated dmso molecules are observed respectively at
δ 2.50 and 2.80 (JPt-H ) 15 Hz). These signals are assigned to
[Pt(C6H3Me2-3,5)2(PhpyH)(dmso)] (A), having the two aryl
ligands in cis positions, an N-coordinated PhpyH ligand, and
an S-coordinated dmso molecule. The ratio of A to 1a is close
to 1:1 immediately after mixing PhpyH and 1a. The reactions
of PhpyH with 1b,c and 2b also form complexes with similar
structures, [PtAr2(PhpyH)(solv)], but the ratios of the complexes
with and without the PhpyH ligand are highly dependent on
both the aryl ligand and coordinating solvent molecule. In the
reaction of 1b,c, the ratio of the intermediate complex to the
starting complex is also about 1:1, whereas complex 2b is almost
converted to [Pt{C6H3(CF3)2-3,5}2(PhpyH)(NCCH3)] in the
reaction mixture, probably because acetonitrile is less donating
than dmso. The complexes with a PhpyH ligand are stable at
room temperature in solution.
Figure 3c shows the NMR spectrum after the reaction for 10
h at 50 °C. The signals of A are not observed after heating.
Newly observed signals at δ 9.73, 6.75, and 6.60 are assigned
to complex 3a. Heating at 50 °C also engenders the formation
of 3b,c and 4b from the reaction mixtures, respectively, using
1b,c, and 2b.
A plausible mechanism for the total reaction is depicted in
Scheme 1. First, one of the coordinated solvent molecules of
the diaryl complex is replaced by 2-phenylpyridine, which
creates the intermediate complex A observed in 1H NMR spectra
and in the crystal structure of 5 (vide infra). Then, the remaining
solvent molecule probably dissociates from complex A; also,
oxidative addition of the ligand to the platinum center ac-
companied by C-H activation gives the platinum(IV) hydride
complex B. Two possible structures can be inferred for the
intermediate B. Reductive elimination of hydride and one aryl
group proceeds to give the cyclometalated platinum(II) com-
plexes 3a-c and 4b. It has been reported that this reductive
elimination proceeds though the pentacoordinated square-
pyramidal species.12b,17
The intermediate complexes of the reaction, [Pt(Ar)2(PhpyH)-
1
(solv)] (A), were characterized using the H NMR spectra of
the mixtures and assigned to the intermediate complexes for
formation of 3a-c and 4b. Isolation or characterization by X-ray
crystallography was not feasible. However, the reaction of
2-phenyl-5-(trifluoromethyl)pyridine (PhCF3pyH) with 1a pro-
duces [Pt(C6H3Me2-3,5)2(PhCF3pyH)(dmso)] (5), which was
obtained as crystals suitable for X-ray crystallography. Figure
4 shows the molecular structure of the complex. It has a
distorted-square-planar platinum center that is bonded to two
aryl groups with a cis configuration, a nitrogen atom of PhCF3-
pyH, and a sulfur atom of the dmso molecule. Selected bond
lengths and angles are given in Table 1. The Pt-C bond
Figure 4. ORTEP drawing of 5 (50% probability).

Monoarylplatinum(II) Complexes
Organometallics, Vol. 26, No. 9, 2007 2387
Scheme 2
distances (2.033(4) and 2.016(4) Å) and Pt-S1 bond distance
(2.287(1) Å), which are longer than those of [PtCl2(dmso)2],
are similar to the crystallographic results of 1a. In addition, the
Pt-N1 bond (2.143(4) Å) is also extended, as shown in many
organoplatinum complexes whose nitrogen atoms are trans to
Pt-C bonds. The isolated complex 5 undergoes cyclometalation
to give an arylplatinum(II) complex analogue of 3a, [Pt(C6H3-
Me2-3,5)(PhCF3py)(dmso)] (6), in acetone at 50 °C (Scheme
2). Rates of the cyclometalation reactions are very sensitive to
the aryl ligand and coordinating solvent. At 50 °C, the reactions
of PhpyH with equimolar 1a,c and 2b, giving 3a,c and 3b, are
completed in 10 h, 1 day, and 3 days, respectively, whereas 1b
is converted into 3b in about 30% yield after 2 weeks. The
formation of 3a-c becomes faster in the order 3a > 3c > 3b,
which is related to the cyclometalation of the intermediate
complexes [Pt(Ar)2(PhpyH)(solv)]. Complexes having more
electron-donating substituents at the aryl group undergo faster
cyclometalation. The cyclometalation involves oxidative addition
of the C-H bond to the Pt(II) center, which is now common in
organoplatinum chemistry, and subsequent reductive elimination
of arene via coupling of the formed hydride ligand and an aryl
ligand. The different rates of cyclometalation depending on the
aryl group are probably attributable to reductive elimination,
by which the electron-donating substituent of the aryl ligand
enhances the reaction. Complex 2b with an acetonitrile ligand
undergoes much faster ligation and cyclometalation than 1b,
despite having the same aryl ligand. Exchange of the solvent
ligand of 2b with added PhpyH ligand proceeds much more
smoothly than that of 1b because acetonitrile shows a less
donating and more labile nature than dmso. To elucidate this
matter further, we investigated the reaction of PhpyH with
equimolar 2b in acetonitrile-d3 at 50 °C. The 1H NMR spectra
at the initial stage showed that the ratio of the intermediate
complex to the starting complex is about 6:4, with quantitative
formation of the intermediate complex in acetone-d6. The
following reaction at 50 °C gave 4b in 36% yield, even after 2
weeks. The lower yield of 4b as compared to that in acetone-
d6 is attributable to the stronger affinity of CH3CN to the
platinum center. As an explanation of these solvent effects, we
infer that the more strongly donating solvent molecule interrupts
the displacement by PhpyH to form the intermediate complex.
That molecule also interrupts both the subsequent cyclometa-
lation and the dissociation of the coordinating solvent from the
intermediate complex. Thus, the coordinated and free solvents
strongly affect the cyclometalation of the solvated diarylplatinum
complexes: it is important to choose a less donating and more
labile solvent for the reaction. Considering its greater lability
and convenience for aftertreatment of acetonitrile, complex 2b
is a good starting material for cyclometalation.
ligand by CD3CN within 5 min at 25 °C, to produce [Pt{C6H3-
(CF3)2-3,5}(Phpy)(NCCD3)] (4b-CD3CN) (eq 3).
To compare the rate of exchange reaction by the isotope
dilution method of 1H NMR spectroscopy, [Pt{C6H3(CF3)2-3,5}-
(NCCH3)(bpy)]+ (bpy ) 2,2′-bipyridine) was prepared. The
signal of CH3CN bonded to Pt (δ 2.51) decreased, accompanied
by the growth of the signal of free CH3CN (δ 1.95). Completion
of the reaction requires 5 h at 25 °C. Consequently, the exchange
of the coordinated solvent of 4b occurs much more rapidly than
for the cationic complex with bpy ligand. This rapid exchange
is attributable to the strong Pt-C σ-bond of the Phpy ligand of
4b, which promotes facile dissociation of CH3CN at the trans
position. Acceleration of the exchange reaction, which is caused
by the increased number of binding carbon atoms on the metal
center, was reported by van Eldik et al. for substitution reactions
of platinum complexes.18
Although complex 3b has not been obtained easily from direct
cyclometalation of 1b with the 2-phenylpyridine ligand, it can
be prepared independently from the reaction of dmso with 4b,
as shown in eq 4. The substitution of the acetonitrile ligand
Reactions of Cyclometalated Complexes 3a and 4b. The
arylplatinum(II) complexes with the chelating Phpy ligand
contain labile solvent ligand. The respective exchange reactions
of CH3CN of 4b with CD3CN and dmso were conducted.
Dissolution of 4b in CD3CN causes exchange of the CH3CN
takes place at room temperature. As shown in the exchange
reaction of eq 3, an arylplatinum complex with a bidentate Phpy

2388 Organometallics, Vol. 26, No. 9, 2007
Yagyu et al.
Table 3. Selected Bond Distances (Å) and Angles (deg) for
7b
Pt1-N1
Pt1-C1
Pt1-C9
2.147(4)
2.066(6)
2.031(6)
Pt1-I1
Pt1-I2
Pt1-I1*
2.6680(5)
2.6278(5)
2.8232(4)
I1-Pt1-I1*
I1-Pt1-I2
85.67(1)
177.60(1)
86.8(1)
91.4(2)
91.5(2)
94.46(1)
95.2(1)
89.4(2)
I1*-Pt1-C9
I2-Pt1-N1
I2-Pt1-C1
I2-Pt1-C9
N1-Pt1-C1
N1-Pt1-C9
C1-Pt1-C9
Pt1-I1-Pt1*
174.1(1)
90.8(1)
91.0(2)
88.1(2)
174.9(2)
79.5(2)
95.8(2)
94.33(1)
I1-Pt1-N1
I1-Pt1-C1
I1-Pt1-C9
I1*-Pt1-I2
I1*-Pt1-N1
I1*-Pt1-C1
than the iodine atom. The structure of the product (7a) for the
reaction of 3a is considered to resemble that of 7b on the basis
of elemental analyses and the following results of further
reaction with I-.
Although complexes 7a,b dissolved little in any of the
common solvents we used, the addition of an iodide anion such
as Et4NI or NaI into their acetone solutions brought about their
dissolution and gave complexes 8a,b, respectively, which were
observed using 1H NMR spectroscopy. Their spectra show
signals of the aryl and Phpy ligands, which probably imply the
generation of the monomeric complexes [PtI3Ar(Phpy)]-.
Scheme 3 summarizes these reactions.
Figure 5. ORTEP drawing of 7b (50% probability). Atoms with
asterisks are crystallographically equivalent to those having the same
number without an asterisk.
ligand shows higher reactivity than a cationic Pt complex with
a bpy ligand because of the facile dissociation of the ligated
solvent.
We examined the reactions of the complexes with high
reactivity to oxidative addition of I2 to Pt(II). The reactions of
I2 with 3a,b and 4b in acetone-d6 gave orange precipitates as
reaction products and were completed in 1 h at room temper-
ature. Isolated orange precipitates show solubility in general
Summary
We prepared the acetonitrile-solvated diarylplatinum(II)
complex 2b through dissolution of [PtAr2(cod)] into acetonitrile
when C6H3(CF3)2-3,5 was used as the aromatic ligand. Although
1b, which has an electron-withdrawing C6H3(CF3)2-3,5 group,
is inferior to 1a, which has an electron-donating group for
cyclometalation through the Pt(II)/Pt(IV) system, considering
the lability and convenience for aftertreatment of acetonitrile,
complex 2b is a good starting material for cyclometalation.
Complex 4b, resulting from cyclometalation, is very labile for
acetonitrile exchange compared to the corresponding cationic
arylplatinum(II) complex because it has two strong Pt-C σ
bonds. Cyclometalated complexes 3a,b and 4b are also labile
to oxidative addition of I2 and gave the corresponding iodo-
bridged dimeric Pt(IV) complexes.
1
solvent that is too low to be characterized using H NMR
spectroscopy. However, the reaction of I2 with 4b without
stirring the reaction mixture gave single crystals of the products
suited for X-ray analysis. Figure 5 gives perspective views of
the dimeric platinum(IV) complex [(Pt{C6H3(CF3)2-3,5}-
(Phpy)I)2(µ-I)2] (7b), which has C2 symmetry around the center
of the Pt2I2 flat four-membered ring. Each platinum center of
the molecule has a distorted-octahedral environment and is
coordinated to the aryl group, C-N bidentate Phpy ligand, and
bridging and nonbridging iodo ligands. The bidentate C-N
ligand and the carbon atom of aryl group are oriented in the
meridian plane with the same orientation in the square-planar
platinum(II) complex 4b, which implies oxidative addition of
I2 through attack at the apical sites of the coordination plane of
the platinum(II) complex, as described for addition of CH3I.19
Selected bond distances and angles are given in Table 3. The
two Pt-C bond distances have values similar to those of other
organoplatinum(IV) complexes,20 but they are slightly elongated
from those of 3a,c. The iodide bridges are asymmetric with Pt-I
distances of 2.6680(5) and 2.8232(4) Å, which is probably
attributable to the carbon atom having a stronger trans effect
Experimental Section
General Considerations, Measurement, and Materials. Ma-
nipulations of the platinum complexes were carried out in air
without noting. Then [PtAr2(cod)] and [PtArI(cod)] (Ar ) C6H3-
Me2-3,5 and C6H3(CF3)2-3,5) were prepared by [PtX2(cod)] (X )
Cl, I) with the corresponding Grignard reagents under nitrogen;
[PtPh2(dmso)2] was prepared according to a method described in
Scheme 3

Monoarylplatinum(II) Complexes
Organometallics, Vol. 26, No. 9, 2007 2389
3
the literature.13 The other chemicals were commercially available.
The 1H NMR spectra were recorded on a Varian 300 spectrometer.
Elemental analyses were carried out using a Perkin-Elmer 2400
series II CHNS/O analyzer.
7.10 (s, 2H, o-C6H2H, JH-Pt ) 67 Hz), 7.38 (m, 1H, H5), 7.72
(dd, 1H, H6′, 8 and 1 Hz), 8.04-8.06 (m, 2H, H3 and H4), 9.70
(dd, 1H, H6, 6 and 1 Hz).
Preparation of [Pt{C6H3(CF3)2-3,5}(Phpy)(dmso)] (3b). To an
acetone (2 mL) solution of [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)]
(4b; 105 mg, 0.174 mmol) was added dmso (12.4 µL, 0.174 mmol).
The mixture was stirred at room temperature for 2 h, and the solvent
was removed. Crystallization of the residue from Et2O-hexane gave
the complex as a yellow powder (76.0 mg, 68.2%). Anal. Calcd
for C21H17F6NOPtS: C, 39.38; H, 2.68; N, 2.19. Found: C, 39.44;
H, 2.75; N, 2.03. 1H NMR (300 MHz, acetone-d6): δ 2.99 (s, 6H,
Preparation of Diarylplatinum Complexes with dmso, [PtAr2-
(dmso)2] (1a,b). The preparation of the complexes was performed
according to a modified method of that for [PtPh2(dmso)2]. First,
[Pt(C6H3Me2-3,5)2(cod)] (206 mg, 0.401 mmol) was dissolved in
10 mL of dmso and the solution stirred at 80 °C for 1 h. After
removal of the solvent under vacuum, recrystallization of the residue
from CH2Cl2-hexane gave [Pt(C6H3Me2-3,5)2(dmso)2] (1a) as a
colorless, air-stable powder (200 mg, 88.8%). Single crystals
suitable for an X-ray diffraction study were obtained through further
recrystallization from CH2Cl2-hexane. Anal. Calcd for C20H30O2-
PtS2: C, 42.77; H, 5.38. Found: C, 42.87; H, 5.46. 1H NMR (300
MHz, CDCl3): δ 2.14 (s, 12H, CH3C6H3), 2.78 (s, 12H, CH3S,
3JH-Pt ) 14 Hz), 6.46 (s, 2H, p-C6H2H), 6.93 (s, 4H, o-C6H2H,
3JH-Pt ) 71 Hz).
3
3
CH3S, JH-Pt ) 16 Hz), 6.30 (dd, 1H, H3′, 8 and 1 Hz and JH-Pt
) 65 Hz), 6.93 (ddd, 1H, H4′, 8, 8, and 1 Hz), 7.08 (ddd, 1H, H5′,
8, 8, and 1 Hz), 7.46 (m, 1H, H5), 7.62 (s, 1H, p-C6H2H), 7.79 (dd,
1H, H6′, 8 and 1 Hz), 8.11-8.12 (m, 2H, H3 and H4), 8.15 (s, 2H,
3
o-C6H2H, JH-Pt ) 69 Hz), 9.71 (dd, 1H, H6, 6 and 1 Hz).
Preparation of [PtPh(Phpy)(dmso)] (3c). To an acetone (30
mL) solution of [PtPh2(dmso)2] (249 mg, 0.493 mmol) was added
Phpy (81 mg, 0.52 mmol). The mixture was stirred at 50 °C for 3
h, and the solvent was removed. Yellow precipitate was generated
as the reaction proceeded. Crystallization of the crude product from
CH2Cl2-hexane gave the complex as a yellow powder (186 mg,
74.8%). Anal. Calcd for C19H19NOPtS: C, 45.23; H, 3.80; N, 2.78.
Complex 1b was prepared using a procedure similar to that for
1a, with [Pt{C6H3(CF3)2-3,5}2(cod)] (400 mg, 0.548 mmol) as the
starting material. The product (374 mg, 87.8%) was obtained as a
colorless, air-stable powder. Single crystals suitable for an X-ray
diffraction study were obtained by recrystallization from Et2O-
hexane. Anal. Calcd for C20H18F12O2PtS2: C, 30.89; H, 2.33.
1
Found: C, 45.20; H, 3.77; N, 2.74. H NMR (300 MHz, CDCl3):
1
3
Found: C, 30.95; H, 2.30. H NMR (300 MHz, CDCl3): δ 2.90
δ 2.93 (s, 6H, CH3S, JH-Pt ) 17 Hz), 6.64 (dd, 1H, H3′, 7 and 1
3
3
(s, 12H, CH3S, JH-Pt ) 15 Hz), 7.41 (s, 2H, p-C6H2H), 7.77 (s,
Hz and JH-Pt ) 68 Hz), 6.98-7.11 (m, 5H, H4′, H5′, m-C6H2H3,
3
4H, o-C6H2H, JH-Pt ) 71 Hz).
and p-C6H4H), 7.25 (ddd, 1H, H5, 7, 6, and 2 Hz), 7.52 (dd, 2H,
3
Preparation of a Diarylplatinum Complexes with CH3CN.
[Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (2b). Preparation of these com-
plexes was also carried out according to a modified method of that
for [PtPh2(dmso)2].13 First, [Pt{C6H3(CF3)2-3,5}2(cod)] (376 mg,
0.515 mmol) was dissolved in 100 mL of CH3CN and the solution
stirred at 50 °C overnight. Hexane was added to this solution to
extract liberated cod; then the solvent was removed. Crystallization
of the residue from Et2O-hexane gave the complex [Pt{C6H3(CF3)2-
3,5}2(NCCH3)2] (2b) as colorless needlelike crystals (213 mg,
59.0%). Anal. Calcd for C20H12F12N2Pt: C, 34.15; H, 1.72; N, 3.98.
o-C6H2H3, 8 and 1 Hz and JH-Pt ) 65 Hz), 7.61 (dd, 1H, H6′, 8
and 1 Hz), 7.81 (dd, 1H, H3, 8 and 1 Hz), 7.87 (ddd, 1H, H4, 8, 7,
and 2 Hz), 9.66 (dd, 1H, H6, 6 and 2 Hz).
Reactions of [PtAr2(solv)2] (1a-c and 2b) with 2-Phenylpy-
ridine in Acetone-d6 or CD3CN. A typical method of reactions of
[PtAr2(solv)2] with 2-phenylpyridine in acetone-d6 or CD3CN is as
follows. After the diarylplatinum complex (0.050 mmol) was
dissolved in 0.5 mL of the deuterated solvent in the NMR tube, 1
equiv of 2-phenylpyridine (0.050 mmol) was added. The solution
was stored at 50 °C, and the reaction was monitored using 1H NMR
spectra. In the reactions, no byproduct was formed and the reactions
proceeded quantitatively, except for 1b; thus, the reaction time was
determined as the disappearance of the signals for the starting
complex or 2-phenylpyridine. Because the reaction of 1b too so
1
Found: C, 34.16; H, 1.71; N, 3.86. H NMR (300 MHz, CDCl3):
δ 2.23 (s, 6H, CH3CN), 7.37 (s, 2H, p-C6H2H), 7.61 (s, 4H,
3
o-C6H2H, JH-Pt ) 78 Hz).
1H NMR spectra of the mixture using [Pt(C6H3Me2-3,5)2(cod)]
or [PtPh2(cod)] showed formation of the corresponding complexes,
[PtAr2(NCCH3)2], in small amounts. Isolation of the complexes was
not feasible because of their instability in solution.
1
long complete, we decided on conversion to 3b by the H NMR
peak area after 2 weeks.
Preparation of [Pt{C6H3(CF3)2-3,5}(Phpy)(NCCH3)] (4b). To
an acetone (2 mL) solution of [Pt{C6H3(CF3)2-3,5}2(NCCH3)2] (145
mg, 0.206 mmol) was added Phpy (29.0 µL, 0.206 mmol). The
mixture was stirred at 50 °C for 3 days, and the solvent was
removed. Crystallization of the residue from Et2O-hexane gave
the complex as a yellow powder (109 mg, 87.7%). Anal. Calcd for
C21H14F6N2Pt: C, 41.80; H, 2.34; N, 4.64. Found: C, 41.62; H,
Preparation of [Pt(C6H3Me2-3,5)(Phpy)(dmso)] (3a). To an
acetone (4 mL) solution of [Pt(C6H3Me2-3,5)2(dmso)2] (205 mg,
0.365 mmol) was added Phpy (51.0 µL, 0.357 mmol). The mixture
was stirred at 50 °C overnight, and the solvent was removed.
Crystallization of the residue from acetone-hexane gave the
complex as a yellow powder (163 mg, 83.9%). Anal. Calcd for
C21H23NOPtS: C, 47.36; H, 4.35; N, 2.63. Found: C, 47.38; H,
1
2.49; N, 4.48. H NMR (300 MHz, acetone-d6): δ 2.52 (s, 3H,
1
CH3CN), 6.74 (dd, 1H, H3′, 7 and 1 Hz, and 3JH-Pt ) 68 Hz), 6.91
(ddd, 1H, H4′, 7, 7, and 2 Hz), 7.00 (ddd, 1H, H5′, 8, 7, and 1 Hz),
7.37 (ddd, 1H, H5, 7, 5, and 2 Hz), 7.48 (s, 1H, p-C6H2H), 7.67
(dd, 1H, H6′, 8 and 2 Hz), 8.04-8.09 (m, 2H, H3 and H4), 8.07 (s,
4.39; N, 2.57. H NMR (300 MHz, acetone-d6): δ 2.20 (s, 6H,
3
CH3C6H3), 2.89 (s, 6H, CH3S, JH-Pt ) 17 Hz), 6.59 (s, 1H,
p-C6H2H), 6.70 (dd, 1H, H3′, 7 and 1 Hz and 3JH-Pt ) 70 Hz), 6.90
(ddd, 1H, H4′, 7, 7, and 1 Hz), 7.02 (ddd, 1H, H5′, 8, 7, and 1 Hz),
3
2H, o-C6H2H, JH-Pt ) 68 Hz), 8.87 (dd, 1H, H6, 5 and 2 Hz).
(17) (a) Minghetti, G.; Stoccoro, S.; Cinellu, M. A.; Soro, B.; Zucca, A.
Organometallics 2003, 22, 4770. (b) Puddephatt, R. J. Coord. Chem. ReV.
2001, 219-221, 157. (c) Hill, G. S.; Yap, G. P. A.; Puddephatt, R. J.
Organometallics 1999, 18, 1408.
(18) Jaganyi, D.; Reddy, D.; Gertenbach, J. A.; Hofmann, A.; van Eldik,
R. Dalton Trans. 2004, 299.
(19) Rendina, L. M.; Puddephatt, R. J. Chem. ReV. 1997, 97, 1735.
(20) Canty, A. J.; Patel, J.; Rodemann, T.; Ryan, J. H.; Skelton, B. W.;
White, A. H. Organometallics 2004, 23, 3466. Thorshaug, K.; Fjeldahl, I.;
Romming, C.; Tilset, M. Dalton Trans. 2003, 4051. Thoonen, S. H. L.;
Lutz, M.; Spek, A. L.; Deelman, B.-J.; van Koten, G. Organometallics 2003,
22, 1156. Fraser, C. S. A.; Jenkins, H. A.; Jennings, M. C.; Puddephatt, R.
J. Organometallics 2000, 19, 1635. Canty, A. J.; Hoare, J. L.; Patel, J.;
Pfeffer, M.; Skelton, B. W.; White, A. H. Organometallics 1999, 18, 2660.
Preparation of [Pt(C6H3Me2-3,5)2(PhCF3pyH)(dmso)] (5). To
an acetone (1 mL) solution of 1a (40.3 mg, 0.0718 mmol) was
added PhCF3pyH (17.5 mg, 0.0784 mmol). The mixture was stirred
at room temperature for 30 min. The resultant white precipitates
were collected and washed using cold acetone (35.7 mg, 70.3%).
Anal. Calcd for C30H32F3NOPtS: C, 50.99; H, 4.56; N, 1.98.
Found: C, 50.80; H, 4.49; N, 1.87.
Preparation of [Pt(C6H3Me2-3,5)(PhCF3py)(dmso)] (6). To an
acetone (10 mL) solution of 1a (197 mg, 0.351 mmol) was added
PhCF3pyH (82.0 mg, 0.367 mmol). The mixture was stirred at 50
°C for 1 day, and the solvent was removed. Crystallization of the

2390 Organometallics, Vol. 26, No. 9, 2007
Yagyu et al.
residue from Et2O-hexane gave the complex as a yellow powder
of I2 in acetone-d6 (0.5 mL). Spectral changes for their reactions
were monitored at room temperature.
(120 mg, 57.0%). Anal. Calcd for C22H22F3NOPtS: C, 44.00; H,
1
3.69; N, 2.33. Found: C, 43.85; H, 3.86; N, 2.24. H NMR (300
Preparation of [{Pt(C6H3Me2-3,5)(Phpy)I}2(µ-I)2] (7a). To an
acetone (2 mL) solution of 3a (109 mg, 0.205 mmol) was added
iodine (53.4 mg, 0.209 mmol). The mixture was stirred at room
temperature for 5 h. The resultant orange precipitates were collected
and washed using acetone (41.0 mg, 28.2%). Anal. Calcd for
C38H34I4N2Pt2: C, 32.22; H, 2.42; N, 1.98. Found: C, 32.32; H,
2.64; N, 1.78.
MHz, CDCl3): δ 2.25 (s, 6H, CH3C6H3), 2.96 (s, 6H, CH3S, 3JH-Pt
) 17 Hz), 6.67 (s, 1H, p-C6H2H), 6.74 (m, 1H, H3′), 7.07-7.14
(m, 2H, H4′ and H5′), 7.12 (s, 2H, o-C6H2H, 3JH-Pt ) 67 Hz), 7.66
(m, 1H, H6′), 7.91 (d, 1H, H3, 9 Hz), 8.08 (dd, 1H, H4, 9 and 2
Hz), 10.17 (s, 1H, H6). The same complex also formed from the
suspension of 5 in acetone by heating to 50 °C.
Preparation of [PtI{C6H3(CF3)2-3,5}(bpy)]. A CH3CN (40 mL)
solution of [PtI{C6H3(CF3)2-3,5}(cod)] (314 mg, 0.488 mmol) and
bpy (381 mg, 2.44 mmol) was stirred at room temperature for 3
days. Hexane was added to the solution to extract librated cod;
then the solvent was removed. Crystallization of the residue from
CH2Cl2-hexane gave the complex as a yellow powder (305 mg,
90.4%). Anal. Calcd for C18H11F6IN2Pt: C, 31.28; H, 1.60; N, 4.05.
Preparation of [(Pt{C6H3(CF3)2-3,5}(Phpy)I)2(µ-I)2] (7b). To
an acetone (2 mL) solution of 4b (64.1 mg, 0.100 mmol) was added
iodine (31.6 mg, 0.125 mmol). The mixture was stirred at room
temperature for 1 h. The resultant orange precipitates were collected
and washed using acetone (30.4 mg, 37.2%). Anal. Calcd for
C38H22F12I4N2Pt2: C, 27.96; H, 1.36; N, 1.72. Found: C, 28.25;
H, 1.39; N, 1.59.
1
Found: C, 31.36; H, 1.50; N, 4.01. H NMR (300 MHz, acetone-
Preparation of Et4N[Pt(C6H3Me2-3,5)(Phpy)I3] (8a-Et4N). To
an acetone (4 mL) solution of 7a (33.3 mg, 0.0204 mmol) was
added Et4NI (10.6 mg, 0.0412 mmol). The mixture was stirred at
room temperature for 1 day, and the solvent was removed.
Crystallization of the residue from acetone-hexane gave the
complex as an orange powder (27.5 mg, 69.9%). Anal. Calcd for
C27H37I3N2Pt: C, 33.59; H, 3.86; N, 2.90. Found: C, 33.22; H,
d6): δ 7.45 (s, 1H, p-C6H2H), 7.68 (ddd, 1H, H5′, 8, 6, and 1 Hz),
7.88 (ddd, 1H, H5, 8, 5, and 1 Hz), 7.93 (s, 2H, o-C6H2H, 3JH-Pt
)
3
42 Hz), 8.12 (dd, 1H, H6′, 6 and 2 Hz and JH-Pt ) 59 Hz), 8.41
(ddd, 1H, H4, 8, 8, and 2 Hz), 8.47 (ddd, 1H, H4′, 8, 8, and 2 Hz),
8.62-8.68 (m, 2H, H3 and H3′), 9.97 (dd, 1H, H6, 5 and 2 Hz).
Preparation of [Pt{C6H3(CF3)2-3,5}(NCCH3)(bpy)]BF4. A
small excess of AgBF4 was added to a solution of [PtI{C6H3(CF3)2-
3,5}(bpy)] (85 mg, 0.12 mmol) in dry CH3CN under argon. The
mixture was stirred for 1 min at room temperature; then the resulting
precipitate of AgI was filtered off. The crude product obtained by
addition of Et2O to the concentrated filtrate was recrystallized from
CH3CN-Et2O to give the off-white complex (81 mg, 100%). Anal.
Calcd for C20H14BF10N3Pt: C, 34.70; H, 2.04; N, 6.07. Found: C,
1
4.04; N, 2.76. H NMR (300 MHz, acetone-d6): δ 1.34 (t, 12H,
NCH2CH3, 7 Hz), 2.17 (s, 6H, CH3C6H3), 3.41 (q, 8H, NCH2CH3,
7 Hz), 6.45 (s, 1H, p-C6H2H), 6.89 (ddd, 1H, H5′, 8, 7, and 1 Hz),
7.11 (ddd, 1H, H4′, 7, 7, and 2 Hz), 7.32 (1H, H5, overlapping with
the signal at δ 7.38), 7.38 (d, 1H, H3′, 7 Hz, and 3JH-Pt ) 36 Hz),
7.85 (dd, 1H, H6′, 8 and 2 Hz), 7.93 (ddd, 1H, H4, 8, 7, and 2 Hz),
3
8.20 (d, 1H, H3, 8 Hz), 8.32 (s, 2H, o-C6H2H, JH-Pt ) 39 Hz),
1
34.68; H, 2.22; N, 6.00. H NMR (300 MHz, acetone-d6): δ 2.81
10.52 (d, 1H, H6, 6 Hz). The reactions of NaI with 7a showed
similar changes of solutions and analogous 1H NMR spectra, except
for the cation part.
(s, 3H, CH3CN), 7.71 (s, 1H, p-C6H2H), 7.73 (1H, H5′, overlapping
with the signal at δ 7.71), 8.02 (ddd, 1H, H5, 8, 5, and 1 Hz), 8.07
3
(s, 2H, o-C6H2H, JH-Pt ) 44 Hz), 8.28 (dd, 1H, H6′, 6 and 1 Hz,
Preparation of Et4N[Pt(C6H3Me2-3,5)(Phpy)I3] (8b-Et4N). To
an acetone (4 mL) solution of 7b (20.0 mg, 0.0123 mmol) was
added Et4NI (70.0 mg, 0.270 mmol). The mixture was stirred at
room temperature for 3 h, and the solvent was removed. Crystal-
lization of the residue from acetone-hexane gave the complex as
an orange powder (18.0 mg, 68.3%). Anal. Calcd for C27H31F6I3N2-
Pt: C, 30.21; H, 2.91; N, 2.61. Found: C, 30.49; H, 3.05; N, 2.47.
1H NMR (300 MHz, acetone-d6): δ 1.38 (t, 12H, NCH2CH3, 7
Hz), 3.49 (q, 8H, NCH2CH3, 7 Hz), 6.96 (ddd, 1H, H5′, 8, 8, and
3
and JH-Pt ) 57 Hz), 8.50 (ddd, 1H, H4′, 8, 8, and 1 Hz), 8.55
(ddd, 1H, H4, 8, 8, and 2 Hz), 8.72-8.78 (m, 2H, H3 and H3′),
9.21 (dd, 1H, H6, 5 and 2 Hz).
Acetonitrile Exchange Reactions of 4b and [Pt{C6H3(CF3)2-
3,5}(NCCH3)(bpy)]BF4. The sample solution ([Pt complex] ) 5.0
× 10-2 mol kg-1) was prepared under a nitrogen atmosphere by
dissolution of each complex in CD3CN that had been distilled before
use. Spectral changes for their reactions were monitored at 25.0
°C.
3
1 Hz), 7.01 (dd, 1H, H3′, 8 and 1 Hz, and JH-Pt ) 36 Hz), 7.19
Reactions of I2 with 3a,b and 4b. A sample solution was
prepared by dissolution of 0.025 mmol of each complex and 1 equiv
(ddd, 1H, H4′, 8, 8, and 2 Hz), 7.41 (ddd, 1H, H5, 7, 6, and 1 Hz),
7.45 (s, 1H, p-C6H2H), 7.92 (dd, 1H, H6′, 8 and 1 Hz), 8.00 (ddd,
Table 4. Crystallographic Data for Platinum Complexes
1a 1b 3a 3c
C20H18F12O2PtS2 C21H23NOPtS C19H19NOPtS
5
7b
chem formula
formula wt
cryst syst
space group
a, Å
C20H30O2PtS2
561.67
triclinic
P1h (No. 2)
9.117(4)
9.932(3)
13.46(1)
91.99(6)
97.13(7)
112.58(3)
1112(1)
2
C30H32F3NOPtS
706.73
monoclinic
P21/c (No. 14)
8.8977(2)
C19H11F6I2NPt
816.19
777.55
532.57
504.52
orthorhombic
P212121 (No. 19)
8.5086(2)
orthorhombic
Pbca (No. 61)
8.699(2)
monoclinic
P21/n (No. 14)
9.432(5)
triclinic
P1h (No. 2)
8.8419(6)
10.2442(7)
12.442(1)
103.518(3)
105.202(3)
99.250(1)
1027.4(1)
2
b, Å
c, Å
15.8910(7)
19.133(1)
19.281(3)
23.397(4)
8.630(5)
21.46(1)
19.0682(2)
17.1095(4)
R, deg
â, deg
100.75(4)
100.591(1)
γ, deg
V, Å3
2587.0(2)
4
3924.2(1)
8
1715(1)
4
2853.40(10)
4
Z
µ, cm-1
F(000)
64.81
552
1.677
56.66
1488
72.37
2064
82.69
968
50.13
1392
98.66
740
2.638
D
calcd, g cm-3
1.996
0.10 × 0.13 ×
0.20
1.803
0.02 × 0.02 ×
0.10
1.953
0.10 × 0.15 ×
0.20
1.645
0.10 × 0.20 ×
0.20
cryst size, mm
0.13 × 0.19 ×
0.04 × 0.10 ×
0.19
0.10
unique no. of rflns
4487
3335
4500
3451
6493
4498
no. of rflns used (I > 2.00 σ(I))
no. of variables
3719
226
3029
335
2522
226
2304
208
5334
334
3439
262
R1
wR2
0.039
0.097
0.025
0.055
0.066
0.128
0.035
0.080
0.031
0.080
0.027
0.059

Monoarylplatinum(II) Complexes
Organometallics, Vol. 26, No. 9, 2007 2391
1H, H4, 8, 7, and 2 Hz), 8.26 (d, 1H, H3, 8 Hz), 9.33 (s, 2H,
o-C6H2H, 3JH-Pt ) 42 Hz), 10.51 (d, 1H, H6, 6 Hz). The reactions
of NaI with 7b showed similar changes of solutions and analogous
1H NMR spectra, except for the cation part.
factors and anomalous dispersion terms were taken from ref 21.
All non-hydrogen atoms were refined using a full-matrix least-
squares method with anisotropic displacement parameters. Hydrogen
atoms were located by assuming the ideal geometry and included
in the structure calculations without further refinement of the
parameters. All calculations were performed using the teXsan
crystallographic software package of Molecular Structure Corp.22
Crystallographic data and details of the refinement are summarized
in Table 4.
Crystal Structure Determination. Crystals of 1a,b and 3a,c
suitable for X-ray diffraction study were obtained respectively by
recrystallization from CH2Cl2-hexane, Et2O-hexane, Et2O-hex-
ane, and CH2Cl2-hexane; single crystals of 5 were obtained using
the reaction mixture of 1a with 2-phenyl-5-(trifluoromethyl)pyridine
without stirring at room temperature. Single crystals of 7b were
obtained using the reaction mixture of 4b with I2 without stirring.
Crystallographic and diffraction data were obtained using an Enraf-
Nonius CAD4-EXPRESS four-circle diffractometer with graphite-
monochromated Mo KR radiation at room temperature for 1a and
3c and using a Rigaku/MSC Mercury CCD with graphite-mono-
chromated Mo KR radiation at -100 °C for 1b, 3a, 5, and 7b. All
structures were solved using a combination of direct methods and
were expanded using the Fourier technique. Atomic scattering
Supporting Information Available: CIF files giving crystal-
lographic data for 1a,b, 3a,c, 5, and 7b. This material is available
free of charge via the Internet at http://pubs.acs.org.
OM061137M
(21) Cromer, D. T.; Waber, J. T. International Tables for X-ray
Crystallography; Kynoch Press: Birmingham, England, 1974; Vol. IV.
(22) teXsan, Crystal Structure Analysis Package; Molecular Structure
Corp., The Woodlands, TX, 1985 and 1992.