Bis(2,6-dinitroaryl)platinum complexes. 1. Synthesis through transmetalation reactions

Article abstract of DOI:10.1021/om049801r

Complexes cis-Q[Pt(κ²-Ar)(κ¹-Ar)Cl] [Q = Ph₃PCH₂Ph (1), Me₄N (2); κ²-Ar = C₆(NO₂)₂-2,6-(OMe)₃-3,4,5- κ²-C,O;κ¹-Ar = C₆

Full text of DOI:10.1021/om049801r

Organometallics 2004, 23, 3521-3527
3521
Bis(2,6-d in itr oa r yl)p la tin u m Com p lexes. 1. Syn th esis
th r ou gh Tr a n sm eta la tion Rea ction s
J ose´ Vicente,*,† Aurelia Arcas, and Mar´ıa Dolores Ga´lvez-Lo´pez
Grupo de Qu´ımica Organometa´lica,‡ Departamento de Qu´ımica Inorga´nica, Facultad de
Quı´mica, Universidad de Murcia, Apartado 4021, E-30071 Murcia, Spain
Peter G. J ones*,§
Institut fu¨r Anorganische und Analytische Chemie, Technische Universita¨t Braunschweig,
Postfach 3329, 38023 Braunschweig, Germany
Received March 18, 2004
Complexes cis-Q[Pt(κ2-Ar)(κ1-Ar)Cl] [Q ) Ph3PCH2Ph (1), Me4N (2); κ2-Ar ) C6(NO2)2-2,6-
(OMe)3-3,4,5-κ2-C,O; κ1-Ar ) C6(NO2)2-2,6-(OMe)3-3,4,5-κ1-C] have been prepared by reacting
[HgAr2] [Ar ) C6(NO2)2-2,6-(OMe)3-3,4,5] and Q2[Pt2Cl6] (4:1) in acetone at 100 °C. Complex
2 could be prepared by reacting [HgAr2] (i) with [Me4N]2[Pt2Cl6] (2:1) in the presence of an
excess of [Me4N]Cl or (ii) with [Me4N]2[PtCl4] (1:1). The reaction of equimolecular amounts
of 2 and Tl(acac) or AgClO4 gave, respectively, cis-Me4N[Pt(κ1-Ar)2(acac-κ2-O,O)] (3) or cis-
[Pt(κ2-Ar)(κ1-Ar)(OH2)] (4), which in turn reacts with neutral ligands to give cis-[Pt(κ2-Ar)-
(κ1-Ar)L] [L ) PhCN (5), tetrahydrothiophene (6)]. Hg(O2CCF3)2 reacts with an equimolar
amount of 2 to give cis-Me4N[Pt(κ2-Ar)(κ1-Ar){OC(O)CF3}] (7). The structures of complexes
1, 4‚Et2O, 4‚CH2Cl2, and 7 have been solved by X-ray diffraction studies.
In tr od u ction
using the corresponding diaryl mercurials. Two main
types of reactions have been used: transmetalation
reactions, i.e., Cl[M] + [HgR2] f Ar[M] + [Hg(R)Cl], or
redox-transmetalation reactions, i.e., [M] + [Hg(R)Cl]
(or [HgR2]) f [M](R)Cl (or [M]R2) + Hg. Mono-, homodi-,
or heterodiarylcomplexes have been thus prepared. We
have reported the synthesis of two triarylgold(III)
complexes starting from [AuCl4]- and using only mer-
curials as transmetalating agents.18 Other authors have
also found mercurials useful in preparing functionalized
aryl complexes.19 In a few cases diaryl derivatives are
isolated, even when equimolecular amounts of the
reagents are used, because a double transmetalation
occurs, i.e., Cl2[M] + [HgR2] f [M]R2 + HgCl2. We have
observed this behavior when R ) 2-nitroaryl, [M] )
The use of organomercurials as transmetallating
agents has several advantages over the use of the
classical organolithium and Grignard reagents in the
synthesis of organometallic compounds,1 notably the
possibility of preparing functionalized derivatives. Thus,
we have reported the synthesis of aryl complexes
containing ortho-substituents such as -NO2 [Pd(II),2-6
Pt(II),7 Pt(IV),8 Au(I),9 Au(III),10 Rh(III)11], -NH2 [Pt-
(II)12], -CHO [Pd(II)13], -C(O)Me [Pd(II)14], -C(O)NHR
[Pd(II)15], and -NdNR [Au(III),10 Sn(IV),16 Tl(III)17]
† E-mail: jvs@um.es.
‡ http://www.um.es/gqo/.
§ E-mail: p.jones@tu-bs.de.
(1) Sokolov, V. I.; Reutov, O. A. Coord. Chem. Rev. 1978, 27, 89.
(2) Vicente, J .; Arcas, A.; Blasco, M. A.; Lozano, J .; Ram´ırez de
Arellano, M. C. Organometallics 1998, 17, 5374.
AuCl2 , .
- 20 Pt;7 R ) 2-arylazoaryl, [M] ) AuCl2- 21 In the
case of M ) Pd and R ) 2-nitroaryl, the reaction leads
first to [PdR2], and this reacts with the other reaction
product (HgCl2) to give [PdR(µ-Cl)]2.4 In this paper, we
report a new example of this type of double transmeta-
lation in the reaction between [HgAr2] [Ar ) C6(NO2)2-
2,6-(OMe)3-3,4,5] and [Pt2Cl6]2-, giving a diaryl platinum-
(II) complex. We have reported that the related reaction
(3) Vicente, J .; Arcas, A.; Borrachero, M. V.; Hursthouse, M. B. J .
Chem. Soc., Dalton Trans. 1987, 1655. Vicente, J .; Arcas, A.; Borrach-
ero, M. V.; Mol´ıns, E.; Miravitlles, C. J . Organomet. Chem. 1989, 359,
127. Vicente, J .; Arcas, A.; Borrachero, M. V.; de Goicoechea, M. L.;
Lanfranchi, M.; Tiripicchio, A. Inorg. Chim. Acta 1990, 177, 247.
(4) Vicente, J .; Chicote, M. T.; Martin, J .; Artigao, M.; Solans, X.;
Font-Altaba, M.; Aguilo´, M. J . Chem. Soc., Dalton Trans. 1988, 141.
(5) Vicente, J .; Arcas, A.; Borrachero, M. V.; Tiripicchio, A.; Tiri-
picchio-Camellini, M. Organometallics 1991, 10, 3873.
(6) Vicente, J .; Arcas, A.; Borrachero, M. V.; Mol´ıns, E.; Miravitlles,
C. J . Organomet. Chem. 1992, 441, 487.
(13) See for example: Vicente, J .; Abad, J . A.; Rink, B.; Herna´ndez,
F.-S.; Ram´ırez de Arellano, M. C. Organometallics 1997, 16, 5269, and
references therein.
(14) Vicente, J .; Abad, J . A.; Gil-Rubio, J .; J ones, P. G.; Bembenek,
E. Organometallics 1993, 12, 4151.
(7) Vicente, J .; Chicote, M. T.; Martin, J .; J ones, P. G.; Fittschen,
C.; Sheldrick, G. M. J . Chem. Soc., Dalton Trans. 1986, 2215.
(8) Vicente, J .; Chicote, M. T.; Martin, J .; J ones, P. G.; Fittschen,
C. J . Chem. Soc., Dalton Trans. 1987, 881.
(9) See for example: Vicente, J .; Chicote, M. T.; Gonza´lez-Herrero,
P.; Gru¨nwald, C.; J ones, P. G. Organometallics 1997, 16, 3381, and
references therein.
(10) See for example: Vicente, J .; Bermu´dez, M. D.; Carrio´n, F. J .;
J ones, P. G. Chem. Ber. 1996, 129, 1395, and references therein.
(11) See for example: Vicente, J .; Abad, J . A.; Lahoz, F. J .; Plou, F.
J . J . Chem. Soc., Dalton Trans. 1990, 1459, and references therein.
(12) Vicente, J .; Abad, J . A.; Teruel, F.; Garc´ıa, J . J . Organomet.
Chem. 1988, 345, 233.
(15) Vicente, J .; Abad, J . A.; Shaw, K. F.; Gil-Rubio, J .; Ram´ırez de
Arellano, M. C.; J ones, P. G. Organometallics 1997, 16, 4557.
(16) See for example: Vicente, J .; Chicote, M. T.; Ram´ırez de
Arellano, M. C.; J ones, P. G. J . Chem. Soc., Dalton Trans. 1992, 1839,
and references therein.
(17) Vicente, J .; Abad, J . A.; Gutierrez-J ugo, J . F.; J ones, P. G. J .
Chem. Soc., Dalton Trans. 1989, 2241.
(18) Vicente, J .; Bermu´dez, M. D.; Carrio´n, F. J .; J ones, P. G. Chem.
Ber. 1996, 129, 1301.
10.1021/om049801r CCC: $27.50 © 2004 American Chemical Society
Publication on Web 06/05/2004

3522 Organometallics, Vol. 23, No. 14, 2004
Vicente et al.
with [Pd2Cl6]2- leads only to monoaryl-palladium(II)
complexes even when using an excess of the mercurial.2
The interest in nitroaryl complexes is well docu-
mented. Thus, in addition to those we have prepared
using organomercurials,2,7-11 others have been obtained
using organo-lithium or -tin derivatives,22 oxidative
addition reactions,23 arylhydrazonium salts,24 direct
metalation of arenes,25 or nitration of aryl complexes.26
Our interest in the synthesis of nitroaryl complexes is
based on the great stability of these complexessallowing,
for example, the synthesis of one of the few carbonyl
arylpalladium(II) complexes5sand on the study of the
coordination ability of the ortho nitro group. In this
paper we report the synthesis and reactivity toward
neutral and anionic ligands of some 2,6-dinitro-3,4,5-
trimethoxyphenyl platinum(II) complexes. In the fol-
lowing article we will describe the reactivity of some of
these complexes toward carboxylate salts of mercury
and of the oxidative addition of [HgAr2] to Pt(0) to give
di- and trinuclear containing Pt-Hg compounds.27
Ch a r t 1
ligands C6(NO2)2-2,6-(OMe)3-3,4,5-κ1-C and C6(NO2)2-2,6-(OMe)3-
3,4,5-κ2-C,O are represented by Ar, κ1-Ar, and κ2-Ar (see
Chart 1).
Syn th esis of cis-[P h 3P CH2P h ][P t(K2-Ar )(K1-Ar )Cl] (1).
To a suspension of [Ph3PCH2Ph]2[Pt2Cl6] (153.6 mg, 0.12 mmol)
in acetone (10 mL) was added [HgAr2] (335.4 mg, 0.47 mmol).
The suspension was stirred at 100 °C for 2 h in a Carius tube
and, after cooling, filtered through Celite. The filtrate was
concentrated (3 mL), and addition of Et2O (2 mL) gave 1 as a
violet solid. Yield: 236 mg, 92%. Mp: 213-215 °C. IR (cm-1):
ν(Pt-Cl) 310. ΛM ) 97 Ω-1 cm2 mol-1
CDCl3): δ 6.91-7.76 (m, 20 H, Ph), 4.91 (d, 2 H, CH2, J HP
14.1 Hz), 3.96 (s, 3 H, MeO), 3.95 (s, 6 H, MeO), 3.87 (s, 3 H,
MeO), 3.85 (s, 3 H, MeO), 3.80 (s, 3 H, MeO). Anal. Calcd for
C43H40ClN4O14PPt: C, 47.02; H, 3.67; N, 5.10. Found: C, 46.97;
H, 3.39; N, 5.06. Single crystals of 1 were obtained by slow
diffusion of n-hexane into a solution of 1 in acetone.
.
1H NMR (300 MHz,
2
)
Exp er im en ta l Section
The reactions were carried out without precautions to
exclude atmospheric oxygen or moisture. The IR (solid state,
Nujol/polyethylene) and C, H, and N analyses, conductivity
measurement in acetone, and melting point determinations
were carried out as described elsewhere.28 NMR spectra were
recorded in Varian Unity 300 or Bruker AC 200, Avance 300,
or Avance 400 spectrometers at room temperature unless
otherwise stated. Chemical shifts were referred to TMS or
H3PO4 (31P) or CFCl3 (19F). The synthesis of HgR2 was reported
previously.2 The aryl group C6(NO2)2-2,6-(OMe)3-3,4,5 and the
Syn t h esis of cis-Me4N[P t (K2-Ar )(K1-Ar )Cl] (2). To a
suspension of [Me4N]2[PtCl4] (445 mg, 0.92 mmol) in acetone
(10 mL) was added [HgAr2] (655 mg, 0.92 mmol). The suspen-
sion was stirred at 150 °C for 1 h in a Carius tube and then
concentrated to dryness. CH2Cl2 (20 mL) was added, the
suspension filtered, and the resulting solution concentrated
(8 mL). Addition of Et2O (20 mL) gave a suspension that was
filtered, and the solid was air-dried to give complex 2 as a dark
red solid. Yield: 720 mg, 96%. Mp: 185-188 °C. IR (cm-1):
(19) Wu, Y. J .; Ding, L.; Zhou, Z. X.; Du, C. X.; Wang, W. L. J .
Organomet. Chem. 1998, 564, 233. Ding, K. L.; Wu, Y. J .; Wang, Y.;
Zhu, Y.; Yang, L. J . Organomet. Chem. 1993, 463, 77. Wu, Y. J .; Ding,
K. L.; Wang, Y.; Zhu, Y.; Yang, L. J . Organomet. Chem. 1994, 468, 13.
Wu, Y. J .; Liu, Y. H.; Ding, K. L.; Yuan, H. Z.; Mao, X. A. J . Organomet.
Chem. 1995, 505, 37. Singh, H. B.; McWhinnie, W. R. J . Chem. Soc.,
Dalton Trans. 1985, 821. Wong, K. H.; Cheung, K. K.; Chan, M. C.
W.; Che, C. M. Organometallics 1998, 17, 3505. Bonnardel, P. A.;
Parish, R. V.; Pritchard, R. G. J . Chem. Soc., Dalton Trans. 1996, 3185.
Constable, E. C.; Henney, R. P. G.; Leese, T. A.; Tocher, D. A. J . Chem.
Soc., Dalton Trans. 1990, 443. Cross, R. J .; Tennent, N. H. J .
Organomet. Chem. 1974, 72, 21. Bennett, M. A.; Contel, M.; Hockless,
D. C. R.; Welling, L. L.; Willis, A. C. Inorg. Chem. 2002, 41, 844. Clark,
A. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J . J . Organomet.
Chem. 2000, 598, 262. Gu¨l, N.; Nelson, J . H. Polyhedron 1999, 18, 1835.
van der Ploeg, A. F. M. J .; van Koten, G.; Vrieze, K. J . Organomet.
Chem. 1981, 222, 155. Sokolov, V. I.; Troitskaya, L. L.; Reutov, O. A.
J . Organomet. Chem. 1975, 93, C11. Rossell, O.; Sales, J .; Seco, M. J .
Organomet. Chem. 1982, 236, 415.
(20) Vicente, J .; Chicote, M. T.; Arcas, A.; Artigao, M.; J ime´nez, R.
J . Organomet. Chem. 1983, 247, 123.
(21) Vicente, J .; Chicote, M. T.; Bermu´dez, M. D.; Solans, X.; Font-
Altaba, M. J . Chem. Soc., Dalton Trans. 1984, 557.
(22) Brune, H. A.; Stapp, B.; Schmidtberg, G. J . Organomet. Chem.
1986, 307, 129.
(23) Fitton, P.; Rick, E. A. J . Organomet. Chem. 1971, 28, 287. Beck,
W.; Schorpp, K.; Stetter, K. H. Z. Naturforsch., B 1971, 26, 684.
Vicente, J .; Abad, J . A.; Sa´nchez, J . A. J . Organomet. Chem. 1988, 352,
257.
ν(Pt-Cl) 298. ΛM ) 118 Ω-1 cm2 mol-1 1H NMR (300 MHz,
.
d6-acetone): δ 3.99 (s, 3 H, MeO), 3.97 (s, 3 H, MeO), 3.91 (s,
6 H, MeO), 3.89 (s, 3 H, MeO), 3.88 (s, 3 H, MeO), 3.40 (s, 12
H, Me4N). 13C{1H} NMR (75.45 MHz, d6-acetone): δ 154.92,
154.25, 149.97 (J PtC ) 34 Hz), 148.91, 147.00 (J PtC ) 77 Hz),
143.00 (J PtC ) 15 Hz), 142.53 (J PtC ) 9 Hz), 139.06 (J PtC ) 55
Hz), 128.68 (J PtC ) 1202 Hz, i-C Ar), 113.75 (J PtC ) 1264 Hz,
i-C Ar), 62.58 (OMe), 62.17 (OMe), 62.08 (m-OMe, κ1-Ar), 61.46
(OMe), 61.41 (OMe), 56.00 (t {1:1:1}, Me4N, 1J NC ) 4 Hz). Anal.
Calcd for C22H30ClN5O14Pt: C, 32.26; H, 3.69; N, 8.55. Found:
C, 32.57; H, 3.74; N, 8.56.
Syn th esis of cis-Me4N[P t(K1-Ar )2(a ca c-K2-O,O)] (3). Tl-
(acac) (37 mg, 0.12 mmol) was added to a solution of 2 (101
mg, 0.12 mmol) in acetone (4 mL). The resulting suspension
was stirred for 2 h and then filtered through Celite. The filtrate
was concentrated to dryness, and CH2Cl2 (1 mL) was added.
The suspension was stirred for a few minutes and then was
filtered and the solid air-dried to give pale yellow 3. Yield: 73
mg, 73%. Mp: 252 °C (d). ΛM ) 109 Ω-1 cm2 mol-1. H NMR
(300 MHz, d6-acetone): δ 5.20 (s, 1 H, CH), 3.85 (s, 6 H, MeO),
1
2
3.82 (s, 12 H, MeO), 3.40 (“t” (1:1:1), 12 H, Me4N, J NH ) 0.6
Hz), 1.60 [s, 6 H, MeC(O)]. 13C{1H} NMR (50 MHz, d6-
2
(24) Braunstein, P.; Clark, R. J . H. Inorg. Chem. 1981, 13, 271.
(25) Shilov, A. E.; Shulpin, G. B. Chem. Rev. 1997, 97, 2879.
Shibaeva, R. P.; Rozenberg, L. P.; Lobkovskaya, R. M.; Shilov, A. E.;
Shul’pin, G. B. J . Organomet. Chem. 1981, 220, 271. de Graaf, P. W.
J .; Boersma, J .; van der Kerk, G. J . M. J . Organomet. Chem. 1976,
105, 399.
(26) Clark, G. R.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .; Yap,
V. P. D. Inorg. Chim. Acta 1996, 251, 65. Clark, G. R.; Headford, C. E.
L.; Roper, W. R.; Wright, L. J .; Yap, V. P. D. Inorg. Chim. Acta 1994,
220, 261. Clark, A. M.; Rickard, C. E. F.; Roper, W. R.; Wright, L. J .
Organometallics 1999, 18, 2813.
acetone): δ 183.41 (CO), 152.28 (Ar), 145.92 (Ar, J PtC ) 73
Hz), 142.07 (Ar), 114.61 (CH), 101.41(Ar, 1J PtC ) 62 Hz), 62.09
(OMe), 61.22 (OMe), 55.97 (t (1:1:1), Me4N, 1J NC ) 4 Hz), 26.71
(Me). Anal. Calcd for C27H37N5O16Pt: C, 36.74; H, 4.23; N, 7.93.
Found: C, 36.57; H, 4.13; N, 7.60.
P r ep a r a tion of CH2Cl2 Solu tion s of cis-[P t(K2-Ar )(K1-
Ar )(OH2)] (4). Meth od a . A mixture of 2 (96 mg, 0.12 mmol)
and finely ground AgClO4 (44 mg, 0,21 mmol) in CH2Cl2 (3
mL) was stirred (protected from daylight) for 5 h. The resulting
suspension was filtered to give a red solution.
(27) Vicente, J .; Arcas, A.; Ga´lvez-Lo´pez, M. D.; J ones, P. G.
Organometallics 2004, 23, 3528.
(28) Vicente, J .; Chicote, M. T.; Huertas, S.; Bautista, D.; J ones, P.
G.; Fischer, A. K. Inorg. Chem. 2001, 40, 2051.
Meth od b. AgClO4 (39 mg, 0.12 mmol) was added to a
solution of 2 (57 mg, 0.07 mmol) in acetone (3 mL). After a

Bis(2,6-dinitroaryl)platinum Complexes. 1
Organometallics, Vol. 23, No. 14, 2004 3523
Ta ble 1. Cr ysta llogr a p h ic Da ta for Com p lexes 1, 4, a n d 7
1
4‚Et2O
4‚CH2Cl2
7‚CHCl3
formula
Mr
C
43H40ClN4O14PPt
C22H30N4O16Pt
801.59
C19H22Cl2N4O15Pt
812.40
C25H31Cl3F3N5O16Pt
1015.99
1098.30
habit
red tablet
0.6 × 0.4 × 0.15
monoclinic
P21/n
red tablet
0.6 × 0.6 × 0.25
triclinic
red tablet
red tablet
cryst size (mm)
crystal system
space group
cell constants
a (Å)
0.24 × 0.22 × 0.05
monoclinic
P21/n
0.27 × 0.14 × 0.07
monoclinic
P1h
P21/c
10.7880(10)
18.1386(16)
22.673(2)
90
93.020(7)
90
4430.6(7)
4
1.647
3.34
2192
-100
52
10 147
8654
0.58-0.88
0.032
577
8.606(3)
11.552(5)
14.680(4)
93.59(3)
102.60(3)
91.88(3)
1419.9(9)
2
1.875
5.02
792
-130
50
5038
5018
10.4998(6)
9.3162(6)
27.0169(16)
90
90.890(3)
90
2642.4(3)
4
2.042
5.59
1584
-140
60
55 628
7732
0.52-0.89
0.073
384
16.0619(6)
13.1120(5)
17.5245(6)
90
94.589(3)
90
3678.9(2)
4
1.834
4.12
2000
-140
60
73 304
10 751
0.64-0.89
0.042
520
b (Å)
c (Å)
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
Dx (Mg m-3
)
µ (mm-1
F(000)
T (°C)
2θmax
)
no. of reflns measd
no. of indep reflns
transmns
0.45-0.99
Rint
no. of params
restraints
403
334
0.071
0.028
1.05
1.6
520
87
129
wR(F2, all reflns)
R(F, >4σ(F))
S
0.073
0.037
0.87
0.070
0.030
1.03
0.049
0.022
0.95
max ∆F (e Å-3
)
1.1
2.22
1.89
few minutes, the solution was concentrated to dryness and
CH2Cl2 (3 mL) was added. The resulting suspension was
filtered to give a red solution.
Red single crystals of 4‚CH2Cl2 were obtained by slow
diffusion of n-hexane into a solution of 4 in dichlomethane.
P r ep a r a tion of Et2O Solu tion s of 4. A CH2Cl2 solution
of 4 (from 0.12 mmol of 2 and 0.21 mmol of AgClO4) was
concentrated to dryness, and Et2O (5 mL) was added to give a
red solution.
orange solution was concentrated (1 mL). Addition of Et2O (15
mL) gave a suspension, which was filtered, and the solid air-
dried to give 6 as an orange solid. Yield: 81 mg, 86%. Mp:
207-209 °C. 1H NMR (200 MHz, CDCl3): δ 4.05 (s, 6 H, OMe),
4.02 (s, 3 H, OMe), 3.99 (s, 3 H, OMe), 3.93 (s, 3 H, OMe),
3.83 (s, 3 H, OMe), 3.19 (m, 4 H, tht), 2.12 (m, 4 H, tht). Anal.
Calcd for C22H26N4O14PtS: C, 33.13; H, 3.29; N, 7.02; S, 4.02.
Found: C, 32.95; H, 3.14; N, 6.88; S, 3.75.
Syn th esis of cis-Me4N[P t(K2-Ar )(K1-Ar ){OC(O)CF 3}] (7).
To a solution of 2 (68 mg, 0.08 mmol) in CH2Cl2 (6 mL) was
added Hg(O2CCF3)2 (35.4 mg, 0.08 mmol), and the mixture was
stirred for 10 min and then filtered through Celite. The filtrate
was concentrated to ∼2 mL, and addition of Et2O (15 mL) gave
an oil. By vigorous stirring and cooling in a water/ice bath a
suspension was obtained, which was filtered, and the solid air-
dried to give 7 as a red solid. Yield: 60 mg, 81%. Mp: 179-
181 °C. ΛM (acetone, 5.2 × 10-4 M): 152 Ω-1 cm2 mol-1. IR
(cm-1): νasym(CO2) 1696. 1H NMR (400 MHz, CDCl3): δ 3.99
(s, 12 H, OMe), 3.92 (s, 3 H, OMe), 3.82 (s, 3 H, OMe), 3.25 (s,
Syn th esis of cis-[P t(K2-Ar )(K1-Ar )(OH2)]‚Et2O (4‚Et2O).
Addition of n-pentane to an Et2O (5 mL) solution of 4 (0.12
mmol) gave a suspension, which was filtered, and the solid
air-dried to give red complex 4‚Et2O. Yield: 75 mg, 75%. Dec
point: 153-166 °C (see Discussion). IR (cm-1): ν(OH) 3430.
1H NMR (300 MHz, CDCl3): δ 4.03 (s, 12 H, MeO), 3.87 (s, 6
3
H, MeO), 3.51 (q, 4 H, CH2, J HH ) 6.9 Hz), 1.21 (t, 6 H, Me,
1
3J HH ) 6.9 Hz) (See Discussion). H NMR (300 MHz, CDCl3,
-30 °C): 6.03 (s, 1 H, H2O), 4.06 (s, 6 H, MeO), 4.04 (s, 3 H,
MeO), 4.02 (s, 3 H, MeO), 3.91(s, 3 H, MeO), 3.82 (s, 3 H, MeO),
1
3
12 H, Me4N). H NMR (400 MHz, CDCl3, -30°C): δ 4.04 (s, 3
3.54 (q, 4 H, CH2, J HH ) 7 Hz), 2.38 (s, 1 H, H2O), 1.22 (t, 6
3
H, OMe), 4.02 (s, 6 H, OMe), 4.01 (s, 3 H, OMe), 3.94 (s, 3 H,
OMe), 3.81 (s, 3 H, OMe), 3.27 (s, 12 H, Me4N). 19F{1H} NMR
(188.3 MHz, CDCl3): δ -74.05 (s). Anal. Calcd for C24H30F3-
N5O16Pt: C, 32.15; H, 3.37; N, 7.81. Found: C, 32.02; H, 3.14;
N, 7.61. Crystals of 7‚CHCl3 suitable for X-ray diffraction
studies were obtained by slow diffusion of n-hexane into a
solution of 7 in CHCl3.
H, Me, J HH ) 7 Hz). Red single crystals of 4‚Et2O were
obtained by slow diffusion of n-pentane into a solution of
4‚Et2O in Et2O. Anal. Calcd for C22H30N4O16Pt: C, 32.97; H,
3.77; N, 6.99 Found: C, 33.09; H, 3.59; N, 7.36.
Syn th esis of cis-[P t(K2-Ar )(K1-Ar )(NCP h )] (5). To a solu-
tion of 4 (from 0.09 mmol of 2) in Et2O (15 mL) was added
PhCN (9.7 mg, 0.09 mmol), and the resulting solution was
concentrated (3 mL). Addition of n-hexane (15 mL) gave a
suspension, which was filtered, and the solid air-dried to give
5 as an orange solid. Yield: 73 mg, 96%. Mp: 183-185 °C. IR
(cm-1): ν(CtN) 2272. 1H NMR (300 MHz, CDCl3): δ 7.80 (dd,
X-r a y Str u ctu r e Deter m in a tion s. Numerical details are
presented in Table 1. Data collection and reduction: Crystals
were mounted in inert oil on glass fibers and transferred to
the cold gas stream of the diffractometer (1: Siemens P4;
4‚Et2O: Stoe STADI-4; others: Bruker SMART 1000 CCD;
with appropriate low-temperature attachments). Measure-
ments were performed with monochromated Mo KR radiation.
Absorption corrections were performed on the basis of psi-scans
(1 and 4‚Et2O) or multiscans (program SADABS). Structure
refinement: The structures were refined anisotropically against
F2 (program SHELXL-97, G. M. Sheldrick, University of
Go¨ttingen). Solvent molecules were well-ordered except as
indicated below. Hydrogen atoms were included as rigid
3
4
2 H, o-H, J HH ) 8.1 Hz, J HH ) 1.2 Hz), 7.73 (tt, 1 H, p-H,
3J HH) 8 Hz, J HH) 1.2 Hz), 7.54 (t, 2 H, m-H, J HH ) 8 Hz),
4.05 (s, 6 H, OMe), 4.022 (s, 3 H, OMe), 4.017 (s, 3 H, OMe),
3.94 (s, 3 H, OMe), 3.84 (s, 3 H, OMe). Anal. Calcd for
4
3
C
25H23N5O14Pt: C, 36.95; H, 2.85; N, 8.62. Found: C, 36.70;
H, 2.81; N, 8.58.
Syn th esis of cis-[P t(K2-Ar )(K1-Ar )(th t)] (6). To a solution
of 4 (from 0.12 mmol of 2) in CH2Cl2 (3 mL) was added
tetrahydrothiophene (tht) (0.12 mmol), and the resulting

3524 Organometallics, Vol. 23, No. 14, 2004
Vicente et al.
Sch em e 1
Sch em e 2
methyl groups or with a riding model. Systems of restraints
to local ring symmetry and light atom displacement factor
components were employed to improve refinement stability.
Special features of refinement: In compound 1 the methoxy
group O25-C29 is disordered over two positions, which were
refined isotropically in the ratio 1:1. The water hydrogens in
both forms of compound 4 were identified in difference
syntheses and refined with restrained O-H distances. In
compound 7 the CF3 group is disordered over two positions in
the ratio 7:3.
Resu lts a n d Discu ssion
Syn th esis of Com plexes. When a mixture of [HgAr2]
[Ar ) C6(NO2)2-2,6-(OMe)3-3,4,5] and Q2[Pt2Cl6] (4:1) in
acetone was heated in a Carius tube, a transmetalation
reaction occurred leading to cis-Q[Pt(κ2-Ar)(κ1-Ar)Cl]
[Q ) Ph3PCH2Ph (1), Me4N (2); see Chart 1 and Scheme
1]. These complexes can be easily precipitated from the
reaction mixture by addition of Et2O. The byproduct,
[Hg(Ar)Cl], remains soluble and can be isolated by
addition of n-hexane. However, a better method for
preparing complex 2 is to use the same reagents in 2:1
molar ratio in the presence of an excess of [Me4N]Cl. In
this way, only half the amount of [HgAr2] is needed,
because Cl- symmetrizes the byproduct [Hg(Ar)Cl],
regenerating [HgAr2] and giving Me4N[HgCl3], which
is easily removed from the reaction mixture because of
its insolubility in CH2Cl2. We have previously reported
this transmetalation/symmetrization method for the
synthesis of other aryl complexes.10,13,29 Alternatively,
since [Me4N]Cl reacts with [Me4N]2[Pt2Cl6] to give
[Me4N]2[PtCl4], it is reasonable to assume that in the
above reaction [Me4N]2[PtCl4] is the platinum species
reacting with the mercurial. In fact, this complex can
also be used to prepare 2 by reacting it with [HgAr2] in
a 1:1 molar ratio without adding [Me4N]Cl. [HgAr2] and
PtCl2 do not react when a solution in acetone is heated
at 150 °C in a Carius tube.
isolated along with 50% of unreacted Q2[Pt2Cl6]. This
result contrasts with that obtained in the reaction
between [HgAr2] and the palladium complex Q2[Pd2Cl6],
which gives the complex Q2[Pd2(κ1-Ar)2Cl2(µ-Cl)2] (Q )
Ph3PCH2Ph, Me4N) even when using an excess of the
mercurial.2 The behavior of [HgAr2] is like that of
[HgAr′2] (Ar′ ) o-nitrophenyl), which reacts with PtCl2
giving [Pt(κ2-Ar′)2] even when using a 1:1 molar ratio
of reagents.7 Probably, these transmetalation reactions
from mercury to platinum involve the simultaneous
transfer of both nitroaryl groups and the resulting
HgCl2 reacts with [HgAr2] to give the isolated byproduct
[Hg(Ar)Cl].
The reaction of equimolecular amounts of 2 and Tl-
(acac) gave cis-Me4N[Pt(κ1-Ar)2(acac-κ2-O,O)] (3) (Scheme
2). When complex 2 and an excess of finely ground
AgClO4 were stirred at room temperature for 5 h in CH2-
Cl2, a red solution was obtained after removing AgCl,
[Me4N]ClO4, and the excess of AgClO4. This solution can
be used as a source of cis-[Pt(κ2-Ar)(κ1-Ar)(OH2)] (4).
This reaction is almost immediate in acetone, probably
because of the greater solubility of AgClO4 in acetone
than in CH2Cl2. The solutions of 4 in organic solvents
(CH2Cl2, CHCl3, acetone, Et2O, toluene) are indefinitely
stable at room temperature. However, all attempts to
isolate 4 gave products containing some of the solvents
used. Thus, addition of n-pentane to Et2O or CH2Cl2
solutions of 4 gave the stable aqua complexes cis-[Pt-
(κ2-Ar)(κ1-Ar)(OH2)]‚Et2O (4‚Et2O) or cis-[Pt(κ2-Ar)(κ1-
Ar)(OH2)]‚CH2Cl2 (4‚CH2Cl2). Both complexes were
We have unsuccessfully attempted to prepare mono-
aryl complexes. Thus, when [HgAr2] was reacted with
Q2[Pt2Cl6] in a 1:1 molar ratio, complex 1 or 2 was
(29) Vicente, J .; Arcas, A.; Chicote, M. T. J . Organomet. Chem. 1983,
252, 257. Vicente, J .; Arcas, A.; J ones, P. G.; Lautner, J . J . Chem. Soc.,
Dalton Trans. 1990, 451.

Bis(2,6-dinitroaryl)platinum Complexes. 1
Organometallics, Vol. 23, No. 14, 2004 3525
F igu r e 1. Ellipsoid representation of the anion of 1 (25%
probability). Selected bond lengths (Å) and angles (deg):
Pt-C(11) 1.978(5), Pt-C(21) 1.985(4), Pt-O(11) 2.088(3),
Pt-Cl 2.3367(16), C(12)-N(11) 1.430(6), C(16)-N(12) 1.484-
(6), C(22)-N(21) 1.468(6), C(26)-N(22) 1.478(7), N(11)-
O(12) 1.213(5), N(11)-O(11) 1.274(5), N(12)-O(17) 1.210-
(5), N(12)-O(16) 1.222(5), N(21)-O(22) 1.215(5), N(21)-
O(21) 1.216(5), N(22)-O(27) 1.185(7), N(22)-O(26) 1.214(7),
C(11)-Pt-C(21) 99.92(19), C(11)-Pt-O(11) 80.10(17),
C(21)-Pt-Cl 89.16(14), O(11)-Pt-Cl 91.20(11), O(12)-
N(11)-O(11) 118.8(4), O(17)-N(12)-O(16) 125.3(5), O(22)-
N(21)-O(21) 123.1(5), O(27)-N(22)-O(26) 122.7(6).
F igu r e 2. Ellipsoid representation of 4‚Et2O (30% prob-
ability). Selected bond lengths (Å) and angles (deg): Pt-
C(11) 1.966(4), Pt-C(21) 1.988(4), Pt-O(11) 2.067(3), Pt-
O(1) 2.112(3), O(11)-N(11) 1.291(5), O(12)-N(11) 1.219(5),
O(16)-N(12) 1.221(5), O(17)-N(12) 1.215(5), O(21)-N(21)
1.208(5), O(22)-N(21) 1.201(5), O(26)-N(22) 1.217(5),
O(27)-N(22) 1.229(5), N(11)-C(12) 1.412(6), N(12)-C(16)
1.470(5), N(21)-C(22) 1.463(5), N(22)-C(26) 1.468(5), C(11)-
Pt-C(21) 102.94(17), C(11)-Pt-O(11) 80.43(15), C(21)-
Pt-O(1) 88.15(15), O(11)-Pt-O(1) 88.44(13), O(12)-N(11)-
O(11) 117.7(4), O(17)-N(12)-O(16) 125.1(4), O(22)-N(21)-
O(21) 123.2(4), O(26)-N(22)-O(27) 123.3(4).
characterized by X-ray diffraction studies, but 4‚CH2-
Cl2 could not be isolated analytically pure. The reaction
of a Et2O or CH2Cl2 solution of 4 with benzonitrile or
tetrahydrothiophene (tht) afforded the complexes cis-
[Pt(κ2-Ar)(κ1-Ar)(NCPh)] (5) and cis-[Pt(κ2-Ar)(κ1-Ar)-
(tht)] (6), respectively, which are stable in the solid state
and in acetone, CH2Cl2, or CHCl3 solutions.
The thermogravimetric analysis of 4‚Et2O shows that
it loses Et2O at 81 °C, and the low-temperature 1H NMR
of the resulting product shows the corresponding signals
of 4, but it is not analytically pure. The molecule of
water is removed at 117 °C, but all the attempts to
isolate analytically pure [Pt(κ2-Ar)2] were unsuccessful.
Thus, when a sample of 4‚Et2O was heated at 117 °C
for 1 h, a complex mixture of products was obtained.
Assuming a cis geometry for the hypothetical complex
[Pt(κ2-Ar)2], in accordance with the X-ray crystal struc-
ture of cis-[Pd(κ2-Ar′)2] (Ar′ ) o-nitrophenyl),4 the
unsuccessful attempts to isolate it may be associated
with the mutual steric hindrance between the nonco-
ordinated nitro groups. However, the κ1-coordination of
one or two ligands in complexes 1-7 releases such steric
hindrance around the PtAr2 moiety because the plane
of the κ1-Ar ligands can be located perpendicular to the
coordination plane, as is shown in the crystal structures
of 4‚Et2O and 4‚CH2Cl2.
F igu r e 3. Ellipsoid representation of 4‚CH2Cl2 (30%
probability; solvent omitted). Selected bond lengths (Å) and
angles (deg): Pt-C(11) 1.969(3), Pt-C(21) 1.986(3), Pt-
O(11) 2.0737(19), Pt-O(10) 2.147(2), N(11)-O(12) 1.206-
(3), N(11)-O(11) 1.288(3), N(11)-C(12) 1.435(4), N(12)-
O(17) 1.220(3), N(12)-O(16) 1.224(3), N(12)-C(16) 1.475(4),
N(21)-O(22) 1.210(4), N(21)-O(21) 1.220(3), N(21)-C(22)
1.480(3), N(22)-O(27) 1.223(3), N(22)-O(26) 1.227(3),
N(22)-C(26) 1.468(4), C(11)-Pt-C(21) 102.30(11), C(11)-
Pt-O(11) 80.89(9), C(21)-Pt-O(10) 87.18(10), O(11)-Pt-
O(10) 89.84(8), O(12)-N(11)-O(11) 119.8(2), O(17)-N(12)-
O(16) 124.9(3), O(22)-N(21)-O(21) 124.1(3), O(27)-N(22)-
O(26) 123.9(3).
While the reaction of 2 with [Hg(OAc)2] (1:1) gave a
heterodinuclear Pt/Hg complex (see following article),27
that with Hg(O2CCF3)2 (1:1) proceeds with substitution
of chloride by carboxylate to give cis-Me4N[Pt(κ2-Ar)-
(κ1-Ar){OC(O)CF3}] (7) (Scheme 2).
Str u ctu r e a n d Sp ectr oscop ic P r op er ties. The
crystal structures of complexes 1 (Figure 1), 4 as the
diethyl ether (Figure 2) and dichloromethane solvate
(Figure 3), and 7 (Figure 4) have been determined. All
of them show an approximately square planar coordina-
tion around the platinum atom with the ligands κ2-Ar
and a κ1-Ar mutually cis. The C-Pt-C angles are
significantly wider than 90° [99.9(2)° (1), 102.94(17)°
(4‚Et2O), 102.30(11)° (4‚CH2Cl2), and 100.02(8)° (7)],
presumably resulting from steric repulsion between the
bulky cis aryl ligands. Associated with this is the narrow
bite of the chelating ligand; the C-Pt-O angles in the
κ2-Ar ligand are significantly less than 90° [80.1(2)° (1),
80.43(15)° (4‚Et2O), 80.89(9)° (4‚CH2Cl2), and 80.52(7)°
(7)]. The Pt-C(κ1-Ar) bond distances are very similar
[1.985(5) Å (1), 1.988(4) Å (4‚Et2O), 1.986(3) Å (4‚CH2-
Cl2), and 1.983(2) Å (7)]; the same applies to Pt-C(κ2-
Ar) [1.976(5) Å (1), 1.966(4) Å (4‚Et2O), 1.969(3) Å (4‚
CH2Cl2), and 1.973(2) Å (7)], although the latter are
slightly shorter, suggesting a somewhat greater trans
influence of the O-nitro ligand than that of chloro, OH2,
or CF3CO2 ligands. A comparative study of the nitroaryl

3526 Organometallics, Vol. 23, No. 14, 2004
Vicente et al.
F igu r e 4. Ellipsoid representation of 7 (30% probability).
Selected bond lengths (Å) and angles (deg): Pt-C(11)
1.973(2), Pt-C(21) 1.983(2), Pt-O(1) 2.0774(16), Pt-O(11)
2.0843(15), N(11)-O(12) 1.220(2), N(11)-O(11) 1.284(2),
N(11)-C(12) 1.426(3), N(12)-O(16) 1.218(2), N(12)-O(17)
1.221(2), N(12)-C(16) 1.486(3), N(21)-O(22) 1.223(2),
N(21)-O(21) 1.232(2), N(21)-C(22) 1.476(3), N(22)-O(27)
1.225(3), N(22)-O(26) 1.228(3), N(22)-C(26) 1.475(3),
C(11)-Pt-C(21) 100.02(8), C(11)-Pt-O(1) 168.91(7), C(21)-
Pt-O(1) 88.82(7), C(11)-Pt-O(11) 80.52(7), C(21)-Pt-
O(11) 174.15(7), O(1)-Pt-O(11) 91.37(6), O(12)-N(11)-
O(11) 119.67(19), O(16)-N(12)-O(17) 124.93(19), O(22)-
N(21)-O(21) 124.05(19), O(27)-N(22)-O(26) 123.8(2).
F igu r e 5. Packing view showing the O-H‚‚‚OMe hydro-
gen bonds (broken lines) in 4‚CH2Cl2.
1.79(4) Å, O(1)‚‚‚O(99) 2.663(5) Å, O(1)-H(02)‚‚‚O(99)
168(5)°] and a longer32 hydrogen bond to the m-O(25)-
Me of the κ1-Ar ligand of a different molecule [H(01)‚‚‚
O(25) 2.06(4) Å, O(1)‚‚‚O(25) 2.830(4) Å, O(1)-H(01)‚‚‚
O(25) 146(5)°; acceptor operator (-x+2, -y+2, -z+2)],
thus forming inversion-related pairs of units 4‚Et2O. In
4‚CH2Cl2 the water molecule bridges two molecules,
establishing two hydrogen bonds with oxygen atoms of
two m-OMe groups of the same κ2-Ar ligand (but via
different operators; Figure 5). The hydrogen bonding
parameters for O(1)-H(01)‚‚‚O(13) (-x, -y+1, -z+1)
are H(01)‚‚‚O(13) 2.13(3) Å, O(1)‚‚‚O(13) 2.838(3) Å,
O(1)-H(01)‚‚‚O(13), 168(6)°; and for O(1)-H(02)‚‚‚O(15)
(x, y + 1, z) are H(02)‚‚‚O(15) 2.24(3) Å, O(1)‚‚‚O(15)
2.933(3) Å, O(1)-H(02)‚‚‚O(15) 164(4)°, forming ribbons
of molecules parallel to the short y axis at z ≈ 0.5. As
would be expected, these compounds also display a
considerable number of “weak” hydrogen bonds of the
form C-H‚‚‚O, details of which are given in the Sup-
porting Information.
group parameters will appear in the following article
reporting other nitroaryl complexes.27 Complexes 4‚Et2O
and 4‚CH2Cl2 show the aqua ligand bonded trans to
the C(11) atom of the chelating Ar ligand. A search of
the Cambridge Structural Database reveals 23 crys-
tal structures of organometallic aqua platinum com-
plexes.30,31 All of them are monoaqua complexes, and
most contain the water molecule trans to a carbon donor
ligand.30 The bond distances and angles for complexes
4‚CH2Cl2 and 4‚Et2O are similar. The only exception is
the Pt-OH2 distance, which is significantly longer in
4‚CH2Cl2 [2.147(2) Å] than in 4‚Et2O [2.112(3) Å],
possibly as a consequence of the different hydrogen
bonds the aqua ligand establishes in each complex. In
4‚Et2O (Figure 2), the water molecule forms a short32
hydrogen bond with the Et2O molecule [H(02)‚‚‚O(99)
As expected, the NMR spectra of complexes 1, 2, and
5-7 show five different MeO groups, consistent with
the structures proposed and with the crystal structure
1
of 1 and 7. However, the H NMR spectra of complexes
4‚Et2O and 4‚CH2Cl2 are not as expected because a
fluxional behavior is observed. Thus, at room temper-
(30) Casas, J . M.; Falvello, L. R.; Fornies, J .; Mansilla, G.; Martin,
A. Polyhedron 1999, 18, 403. Hill, G. S.; Yap, G. P. A.; Puddephatt, R.
J . Organometallics 1999, 18, 1408. Siedle, A. R.; Gleason, W. B.;
Newmark, R. A.; Pignolet, L. H. Organometallics 1986, 5, 1969.
J unicke, H.; Bruhn, C.; Kluge, R.; Serianni, A. S.; Steinborn, D. J . Am.
Chem. Soc. 1999, 121, 6232. Chen, J . T.; Yeh, Y. S.; Lee, G. H.; Wang,
Y. J . Organomet. Chem. 1991, 414, C64. Minghetti, G.; Doppiu, A.;
Stoccoro, S.; Zucca, A.; Cinellu, M. A.; Manassero, M.; Sansoni, M. Eur.
J . Inorg. Chem. 2002, 431. Ito, M.; Ebihara, M.; Kawamura, T. Inorg.
Chim. Acta 1994, 218, 199. Motoyama, Y.; Mikami, Y.; Kawakami, H.;
Aoki, K.; Nishiyama, H. Organometallics 1999, 18, 3584. Deacon, G.
B.; Drago, P. R.; Gobbels, D.; Wickleder, M. S.; Meyer, G. Z. Anorg.
Allg. Chem. 2001, 627, 811. Lukehart, C. M.; McPhail, A. T.; McPhail,
D. R.; Owen, M. D. Chem. Commun. 1990, 215. Baar, C. R.; Carbray,
L. P.; J ennings, M. C.; Puddephatt, R. J . Organometallics 2000, 19,
2482. Dema, A. C.; Lukehart, C. M.; McPhail, A. T.; McPhail, D. R. J .
Am. Chem. Soc. 1989, 111, 7615. Schmulling, M.; Grove, D. M.; van
Koten, G.; van Eldik, R.; Veldman, N.; Spek, A. L. Organometallics
1996, 15, 1384.
(31) J unicke, H.; Bruhn, C.; Muller, T.; Steinborn, D. Z. Anorg. Allg.
Chem. 1999, 625, 2149. Cucciolito, M. E.; Panunzi, A.; Ruffo, F.; Albano,
V. G.; Monari, M. Organometallics 1999, 18, 3482. Cucciolito, M. E.;
Giordano, F.; Ruffo, F.; Defelice, V. J . Organomet. Chem. 1995, 503,
251. Crispini, A.; Harrison, K. N.; Orpen, A. G.; Pringle, P. G.;
Wheatcroft, J . R. J . Chem. Soc., Dalton Trans. 1996, 1069. Canty, A.
J .; Fritsche, S. D.; J in, H.; Honeyman, R. T.; Skelton, B. W.; White, A.
H. J . Organomet. Chem. 1996, 510, 281. Appleton, T. G.; Byriel, K. A.;
Hall, J . R.; Kennard, C. H. L.; Lynch, D. E.; Sinkinson, J . A.; Smith,
G. Inorg. Chem. 1994, 33, 444.
1
ature, the H NMR spectrum of 4‚Et2O in CDCl3 shows
only two MeO resonances (2:1) and no signal from the
molecule of H2O. A variable-temperature 1H NMR study
was performed on 4‚Et2O in CDCl3; at -30 °C it shows
the expected five singlets for the MeO protons and two
broad singlets for the H2O protons. As the temperature
is raised, the MeO singlets broaden, becoming two
singlets at room temperature, and the two water signals
also broaden, move upfield, and disappear at room
temperature. Probably, at room temperature, each aryl
ligand is rapidly changing its coordination mode,
κ2-Ar S κ1-Ar becoming equivalent, whereas at low
temperatures the spectrum shows both different aryl
groups, and a hydrogen bond (probably intramolecular)
makes the water hydrogens inequivalent.
The 1H NMR and 13C{1H} NMR spectra of 3 show two
2:1 singlets corresponding to the MeO groups of both
κ1-Ar ligands. Its IR spectrum shows a medium intensity
band at 452 cm-1 assignable to ν(Pt-O),33 in agreement
(32) Emsley, J . Chem. Soc. Rev. 1980, 9, 91.

Bis(2,6-dinitroaryl)platinum Complexes. 1
Organometallics, Vol. 23, No. 14, 2004 3527
with the chelating nature of the acac ligand. An absorp-
tion at 310 or 298 cm-1 in complexes 1 or 2, respectively,
can be assigned to ν(PtCl). All complexes show very
strong bands in the 1565-1500 cm-1 region correspond-
ing to νasym(NO2). A very strong band around 1350-1365
cm-1 and a medium intensity band in the 1300-1280
cm-1 region are assignable to νsym(NO2) of the nonco-
ordinated nitro groups. Complexes 1, 2, and 4-7 also
show a medium intensity band at around 1250 cm-1
that we assign to νsym(NO2) of the coordinated nitro
groups.2,4,6-8,34
κ2-Ar ligand. These colors fade to pale yellow for 3,
where only κ1-Ar ligands are present.
Con clu sion s
We report the first platinum complexes with the aryl
group C6(NO2)2-2,6-(OMe)3-3,4,5. They are obtained
through a transmetalation reaction from the corre-
sponding diaryl mercurial [HgAr2]. This process always
leads to diaryl platinum complexes.
Ack n ow led gm en t. We thank the Ministerio de
Ciencia y Tecnolog´ıa, FEDER (BQU2001-0133), and the
Fonds der Chemischen Industrie for financial support.
M.D.G.-L. thanks Fundacio´n Se´neca (Comunidad Au-
to´noma de la Regio´n de Murcia, Spain) for a grant.
Color of Com p lexes. In agreement with previous
observations,2 the intense violet, orange, or red color of
complexes 1, 2, and 4-7 is due to the presence of one
(33) Nakamoto, K. Infrared and Raman Spectra of Inorganic and
Coordination Compounds; J ohn Wiley and Sons: New York, 1986.
(34) Vicente, J .; Chicote, M. T.; Gonza´lez-Herrero, P.; Gru¨nwald, C.;
J ones, P. G. Organometallics 1997, 16, 3381. Vicente, J .; Bermu´dez,
M. D.; Carrio´n, F. J .; J ones, P. G. Chem. Ber. 1996, 129, 1395. Vicente,
J .; Abad, J . A.; Lahoz, F. J .; Plou, F. J . J . Chem. Soc., Dalton Trans.
1990, 1459. Vicente, J .; Martin, J .; Solans, X.; Font-Altaba, M.
Organometallics 1989, 8, 357.
Su p p or tin g In for m a tion Ava ila ble: Listing of all refined
and calculated atomic coordinates, anisotropic thermal pa-
rameters, and bond lengths and angles for 1, 4‚Et2O, 4‚CH2-
Cl2, and 7. This material is available free of charge via the
Internet at http://pubs.acs.org.
OM049801R