Heteropolytopic arsanylarylthiolato ligands: Cis-trans isomerism of nickel(II), palladium(II), and platinum(II) complexes of 1-AsPh 2-2-SHC6H4

Article abstract of DOI:10.1021/ic300002p

Heteropolytopic arsanylthiolato ligands 1-AsPh₂-2-SHC ₆H₄ (AsSH), PhAs(2-SHC₆H₄) ₂ (AsS₂H₂), and As(2-SHC₆H ₄)₃ (AsS₃H₃) have been prepared by lithiation-electrophilic substitution procedures. The 2:1 reaction of AsSH with NiCl₂?6H₂O, Na₂[PdCl₄], and [PtI₂(cod)] (cod = 1,5-cyclooctadiene) in the presence of NEt ₃ afforded the square-planar complexes trans-[Ni{(AsS)-k ²S,As}₂] (1), cis-[Pd{(AsS)-k²S,As} ₂] (2), trans-[Pd{(AsS)-k²S,As}₂] (3), and cis-[Pt{(AsS)-k²S,As}₂] (4). In the cases of nickel and platinum, only one isomer was isolated. With palladium, initially the cis isomer 2 is formed and undergoes slow isomerization to the trans isomer 3 in solution. Small amounts of the trinuclear complex [{PtI(1-AsPh₂-μ-2-S- C₆H₄-k²S,As)}₃] (5) are also formed besides the mononuclear platinum bis-chelate complex 4. Density functional theory calculations support a dissociative mechanism for the isomerization of the palladium(II) complexes.

Full text of DOI:10.1021/ic300002p

Article
pubs.acs.org/IC
Heteropolytopic Arsanylarylthiolato Ligands: Cis−Trans Isomerism
of Nickel(II), Palladium(II), and Platinum(II) Complexes of
1-AsPh2-2-SHC6H4
Alexandra Hildebrand,†,‡ Imola Sarosi,†,‡ Peter Lonnecke,‡ Luminita Silaghi-Dumitrescu,†,*
̧
́
̈
Menyhart B. Sarosi,†,‡ Ioan Silaghi-Dumitrescu,†,§ and Evamarie Hey-Hawkins*,‡
́
́
†Faculty of Chemistry and Chemical Engineering, Babes-
‡Institut fur Anorganische Chemie, Universitat Leipzig, Johannisallee 29, D-04103 Leipzig, Germany
̧ Bolyai University, Kogalniceanu 1, RO-400084 Cluj-Napoca, Romania
̈
̈
S
* Supporting Information
ABSTRACT: Heteropolytopic arsanylthiolato ligands 1-
AsPh2-2-SHC6H4 (AsSH), PhAs(2-SHC6H4)2 (AsS2H2), and
As(2-SHC6H4)3 (AsS3H3) have been prepared by lithiation−
electrophilic substitution procedures. The 2:1 reaction of
AsSH with NiCl2·6H2O, Na2[PdCl4], and [PtI2(cod)] (cod =
1,5-cyclooctadiene) in the presence of NEt3 afforded the
square-planar complexes trans-[Ni{(AsS)-κ2S,As}2] (1), cis-
[Pd{(AsS)-κ2S,As}2] (2), trans-[Pd{(AsS)-κ2S,As}2] (3), and
cis-[Pt{(AsS)-κ2S,As}2] (4). In the cases of nickel and
platinum, only one isomer was isolated. With palladium, initially the cis isomer 2 is formed and undergoes slow isomerization
to the trans isomer 3 in solution. Small amounts of the trinuclear complex [{PtI(1-AsPh2-μ-2-S-C6H4-κ2S,As)}3] (5) are also
formed besides the mononuclear platinum bis-chelate complex 4. Density functional theory calculations support a dissociative
mechanism for the isomerization of the palladium(II) complexes.
analysis of [Pt{(Me2AsS)-κ2S,As}2] revealed a trans arrange-
INTRODUCTION
■
ment of the ligands.7f No isomerization of these complexes was
observed upon heating in DMF.
The search for new and more efficient catalytically active
transition-metal complexes is based on the design and synthesis
of appropriate ligands. While phosphorus-based ligands have
been widely explored,1 the combination of arsenic and one or
more sulfur-donor atoms in the same ligand is not widely
exploited. There are, however, examples of transition-metal
complexes of triorganoarsines that are at least as good or even
more efficient catalysts in organic synthesis than the
phosphorus-containing analogues in Stille2a,b and Suzuki−
Miyaura coupling reactions,2c,d hydroformylation of terminal
alkenes,2e Heck olefination,2f carbonylation,2g and asymmetric
Wittig olefination.2h
Recently, our attention focused on the polytopic 10-(o-
alkoxyphenyl)phenoxarsines3 (2-alkoxy- or 2-hydroxyphenyl)-
diphenylarsine4 and (2-alkoxyphenyl)dicyclohexylarsine5 and
the arsanylarylthiolates 1-AsPh2-2-SHC6H4 (AsSH), PhAs(2-
SHC6H4)2 (AsS2H2), and As(2-SHC6H4)3 (AsS3H3) and
preliminary studies on their coordination chemistry.6 Early
studies on arsenic/sulfur-containing derivatives were dedicated
to the coordination chemistry of arsanylarylthioethers.7−10 The
mono- and bis-chelate complexes of dimethyl-o-methylthio-
phenylarsine 1-AsMe2-2-SMe-C6H4 (Me2AsSMe), [PdX2-
{(Me2AsSMe)-κ2S,As}], (X = Cl, Br, I), [PtI2{(Me2AsSMe)-
κ2S,As}], and [Pt{(Me2AsSMe)-κ2S,As}2][PtX4] (X = Cl, Br)
were reported by Livingstone et al.7a,b S-Demethylation of the
ligand occurs when these compounds are heated under reflux in
dimethylformamide (DMF),7c−e and an X-ray crystal structure
The coordination chemistry of the phosphanylarylthiolate
analogues 1-PPh2-2-SHC6H4 (PSH), PhP(2-SHC6H4)2
(PS2H2), and P(2-SHC6H4)3 (PS3H3) is well established.1,6,11
They were synthesized by the reaction of lithium 2-lithio-
benzenethiolate, 1-Li-2-SLi-C6H4, with chlorophosphines
PClnPh3−n (n = 1−3).12,13 Most of the known complexes of
nickel, palladium, and platinum with phenylene-bridged
phosphanylthiolato ligands have been prepared by dealkylation
of the corresponding thioether complexes.8d,14 trans-[Ni{(PS)-
κ2S,P}2] has been structurally characterized in green (mono-
clinic)15 and brown (triclinic)16 modifications. Both cis and
trans isomers of [Pd{(PS)-κ2S,P}2] were obtained from the
reaction of 2 equiv of PSH with Na2[PdCl4] in the presence of
a base.17 trans-[Pd{(PS)-κ2S,P}2] was described previously also
as the product of S-dealkylation of the cationic thioether
complex.14a,18 The structure of [Pt{(PS)-κ2S,P}2] has been
assumed to be trans, but no molecular structure was
reported.18b,c cis-[M{(PS)-κ2S,P}2] (M = Ni, Pd, Pt) was
synthesized by transmetalation reactions of [MCl2(NCPh)2]
(M = Pd, Pt) and NiCl2·6H2O with [SnR2{(PS)-κS}2] (R = Ph,
19
t
nBu, Bu). However, the cis geometry of the nickel complex
Received: January 1, 2012
Published: June 19, 2012
© 2012 American Chemical Society
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Table 1. Crystal Data and Refinement Details for 1−5
1
2
3
4
5
empirical formula
C36H28As2NiS2
C36H28As2PdS2·CH2Cl2
C36H28As2PdS2
C36H28As2PtS2·CH2Cl2
C54H42As3I3Pt3S3·2
CH2Cl2
fw
733.25
865.87
780.94
954.56
2147.64
210(2)
temp (K)
cryst syst
space group
unit cell dimensions
a (Å)
208(2)
monoclinic
P21/c
208(2)
monoclinic
P21/n
210(2)
monoclinic
P21/c
210(2)
monoclinic
P21/n
monoclinic
P21/c
9.7440(7)
12.898(1)
12.783(1)
90
15.498(2)
9.532(1)
9.726(3)
12.768(3)
12.877(3)
90
15.479(4)
9.526(2)
22.771(5)
90
23.988(2)
11.4987(9)
24.100(2)
90
b (Å)
c (Å)
22.842(3)
90
α (deg)
β (deg)
107.552(2)
90
91.746(3)
90
108.045(4)
90
91.836(4)
90
112.635(1)
90
γ (deg)
volume (Å3)
1531.7(2)
2
3372.7(8)
4
1520.4(7)
2
3355.8(14)
4
6135.5(8)
4
Z
density (calcd) (Mg m−3
)
1.590
1.705
1.706
1.889
2.325
abs coeff (mm−1
)
2.939
2.807
2.933
6.449
10.251
F(000)
740
1720
776
1848
3960
cryst size (mm3)
θmin/θmax (deg)
index ranges
0.20 × 0.20 × 0.10
2.19/28.79
−12 ≤ h ≤ 10
−17 ≤ k ≤ 17
−14 ≤ l ≤ 17
8746
0.20 × 0.20 × 0.05
1.61/29.44
−11 ≤ h ≤ 21
−12 ≤ k ≤ 12
−30 ≤ l ≤ 30
20825
0.20 × 0.10 × 0.10
2.20/29.18
−12 ≤ h ≤ 13
−16 ≤ k ≤ 16
−17 ≤ l ≤ 17
14358
0.40 × 0.20 × 0.04
2.32/29.36
−20 ≤ h ≤ 20
−13 ≤ k ≤ 11
−31 ≤ l ≤ 24
20678
0.2 × 0.1 × 0.1
1.70/29.45
−29 ≤ h ≤ 31
−15 ≤ k ≤ 15
−33 ≤ l ≤ 32
57526
reflns collected
indep reflns
3631 [R(int) = 0.0408]
8346 [R(int) = 0.0513]
14358 [R(int) =
0.0000]
8307 [R(int) =
0.0637]
15654 [R(int) =
0.0568]
completeness to θmax (%)
restraints/param
GOF on F2
90.9
89.3
91.5
90.1
91.2
0/187
1.213
0/397
1.012
0/196
0.923
0/397
1.017
0/649
1.151
final R indices [I > 2σ(I)]
R1 = 0.0548,
wR2 = 0.0945
R1 = 0.0437,
wR2 = 0.0930
R1 = 0.0544,
wR2 = 0.1325
R1 = 0.0394,
wR2 = 0.0969
R1 = 0.0574,
wR2 = 0.1020
R indices (all data)
largest diff peak
R1 = 0.0765,
wR2 = 0.1007
R1 = 0.0874,
wR2 = 0.1063
R1 = 0.0927,
wR2 = 0.1392
R1 = 0.0550,
wR2 = 0.1024
R1 = 0.0835,
wR2 = 0.1092
1.060 and −0.754
1.583 and −0.941
1.015 and −1.288
1.992 and −1.922
3.289 and −1.233
and hole (e Å−3
)
a
twin fraction
(ratio domain a/b)
0.60(1)/0.40(1)
a
Twin law by rows: −1.00, 0.00, −0.47; 0.00, 1.00, 0.00; 0.00, 0.00, −1.00.
Crystallographic data (Table 1) were collected on a Siemens CCD
diffractometer (SMART), ω-scan rotation with Mo Kα radiation (λ =
0.71073 Å). Data reduction was performed with SAINT including the
programs SADABS for empirical absorption correction. Direct
methods (compounds 1−4) and Patterson methods (compound 5)
were used to solve the structures. Anisotropic full-matrix least-squares
refinement on F2 of all non-hydrogen atoms was performed with
SHELXL-97. Hydrogen atoms were calculated on idealized positions.
Structure figures were generated with ORTEP (ellipsoids are drawn at
50% probability if not otherwise mentioned).24 The structure deter-
mination of 3 is based on a twinned crystal and was analyzed with the
program GEMINI.25 CCDC 859782 (1), 859783 (2), 859784 (3),
859785 (4), and 859786 (5) contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via www.ccdc.cam.
ac.uk/data_request/cif.
could not be unequivocally confirmed by X-ray diffraction
studies.19
We report here the synthesis of three heteropolytopic
arsanylthiolates AsSH, AsS2H2, and AsS3H3. Complexes (1:2)
of nickel(II), palladium(II), and platinum(II) with AsS− were
prepared and characterized by spectroscopic methods and X-
ray diffraction. In addition, a trimeric complex (Pt:L = 3:3;
L = AsS−) has been obtained.
EXPERIMENTAL SECTION
■
All manipulations were carried out by standard Schlenk and vacuum-
line techniques under an atmosphere of dry nitrogen with dry and
oxygen-free solvents. Ph2AsCl,20 PhAsCl2,21 and [PtI2(cod)] (cod =
1,5-cyclooctadiene)22,23 were prepared according to the literature. All
other chemicals were used as purchased.
All calculations were performed with the Gaussian 09 program
package,26 using the M06 functional27 with the mLANL2DZ basis set
and effective core potential28 for the transition-metal atoms and the 6-
31G** basis set29 for all other atoms. Transition-state structures have
been located with the combined synchronous transit and quasi-
Newton methods.30
Synthesis of AsSH, AsS2H2, and AsS3H3. General Procedure.
Li2(2-S-C6H4)(TMEDA)1.3 was prepared as described in the
literature12 from thiophenol (7 g, 64 mmol), tetramethylethylenediamine
The IR spectra were recorded on a Perkin-Elmer System 2000
Fourier transform infrared spectrometer by scanning between 400 and
1
4000 cm−1 using KBr pellets. The H and 13C NMR spectra were
recorded on a Bruker Avance DRX-400 spectrometer. 1H and 13C
chemical shifts are quoted in parts per million (ppm) at 400.13 and
100.63 MHz, respectively, relative to tetramethylsilane. The mass
spectra were recorded on a VG12-520 mass spectrometer (EI-MS,
70 eV, 200 °C). The melting points were determined in sealed capillaries
with a Gallenkamp instrument and are uncorrected.
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Article
(TMEDA; 21 mL, 141 mmol), and nBuLi (2.3 M in n-hexane; 62 mL,
141 mmol). Li2(2-S-C6H4)(TMEDA)1.3 was obtained as a white solid,
washed with n-hexane, and dissolved in tetrahydrofuran (THF) at
−78 °C. The stirred solution of Li2(2-S-C6H4)(TMEDA)1.3 in THF
(100 mL) was treated dropwise with a solution of chlorodiphenylarsine
(11.75 g, 44 mmol) in THF (20 mL) at −78 °C. The reaction mixture
was warmed to room temperature overnight. The deep-red solution
was acidified at 0 °C with degassed dilute sulfuric acid (6%) to ca.
pH 3−4 and concentrated in vacuum to one-third of its volume, and
the resulting residue was dissolved in diethyl ether (100 mL). The
ether phase was washed with degassed water (3 × 50 mL), dried over
MgSO4, and concentrated to afford crude AsSH. The crude product
was dissolved in diethyl ether. Treatment with activated charcoal,
filtration, and crystallization from diethyl ether/n-hexane (2:1) gave
AsSH as a colorless solid. Yield: 10.51 g, 31 mmol (71% based on
Ph2AsCl). AsS2H2 and AsS3H3 were obtained accordingly from
phenyldichloroarsine or AsCl3, respectively. AsS2H2: yield 3.0 g,
8.1 mmol (56% based on PhAsCl2). AsS3H3: yield 3.2 g, 7.9 mmol
(42% based on AsCl3).
(4:1) layered system at room temperature. Yield: 0.24 g, 0.32 mmol
(97%).
Data for 1. Anal. Calcd for C36H28As2NiS2 (733.27): C, 58.97; H,
3.85. Found: C, 58.46; H, 3.93. 1H NMR (δ, CDCl3): 7.72 (d, 3JHH
=
3
8 Hz, 8H, aryl-H), 7.57 (d, JHH = 8 Hz, 2H, aryl-H), 7.47−7.38 (m,
12H, aryl-H), 7.20 (d, 3JHH = 8 Hz, 2H, aryl-H), 7.16 (t, 3JHH = 8 Hz,
3
2H, aryl-H), 6.94 (t, JHH = 8 Hz, 2H, aryl-H). IR (KBr, cm−1): 3051
(m), 2986 (w), 1953 (w), 1878 (w), 1806 (w), 1579 (m), 1566 (vs),
1550 (m), 1480 (s), 1438 (vs), 1424 (vs), 1304 (w), 1238 (m), 1184
(m), 1157 (w), 1123 (w), 1090 (s), 1081 (s), 1033 (m), 1025 (m),
998 (m), 911 (w), 858 (w), 806 (w), 755 (s), 734 (vs), 715 (m), 690
(vs), 674 (m), 504 (w), 468 (vs), 454 (s), 431 (m). EI-MS: m/z 733.4
([M]+). Mp: 295 °C.
Synthesis of cis-[Pd{(AsS)-κ2S,As}2] (2) and trans-[Pd{(AsS)-
κ2S,As}2] (3). Na2[PdCl4] was prepared from NaCl (66 mg, 1.13
mmol) and PdCl2 (100 mg, 0.56 mmol) in water (25 mL) by stirring
the reactants at 40 °C, cooling to room temperature, and evaporating
to dryness. Na2[PdCl4] was dissolved in MeOH (25 mL) and added to
a solution of AsSH (0.4 g, 1.2 mmol) in MeOH (20 mL) and NEt3
(1.2 mmol). A yellow-orange solid formed immediately. The reaction
mixture was heated to reflux for 2 h. The light-orange solid was
separated by filtration, washed with methanol, and dried in a vacuum.
Slow crystallization from a 2:1 mixture of CH2Cl2/MeOH at room
temperature afforded orange crystals of cis-[Pd{(AsS)-κ2S,As}2] (2).
Yield: 0.39 g, 0.49 mmol (89%).
Data for AsSH.
Data for 2. Anal. Calcd for C36H28As2PdS2 (781.00)·1/4CH2Cl2: C,
1
54.27; H, 3.58. Found: C, 54.37; H, 3.73. H NMR (δ, CDCl3): 7.70
(d, 3JHH = 8 Hz, 6H, aryl-H), 7.66 (d, 3JHH = 8 Hz, 2H, aryl-H), 7.47−
1H NMR (δ, CDCl3): 7.34 (m, 10H, aryl-H), 7.19 (m, 2H, aryl-H),
3
7.40 (m, 10H, aryl-H), 7.23−7.14 (m, 8H, aryl-H), 6.99 (t, JHH
=
3
3
8 Hz, 2H, aryl-H). IR (KBr, cm−1): 3047 (s), 1953 (w), 1880 (w), 1809
(w), 1616 (w), 1566 (vs), 1546 (m), 1480 (s), 1438 (vs), 1421 (vs),
1306 (m), 1241 (m), 1183 (m), 1158 (m), 1121 (w), 1090 (s), 1080
(s), 1033 (m), 1025 (m), 998 (m), 915 (w), 847 (w), 805 (w), 736
(vs), 718 (m), 690 (vs), 656 (w), 503 (w), 470 (vs), 434 (m). EI-MS:
m/z 780.4 ([M]+). Mp: 308−312 °C.
7.05 (t, JHH = 8 Hz, 1H, aryl-H), 6.88 (d, JHH = 8 Hz, 1H, aryl-H),
3.67 (s, 1H, SH). 13C{1H} NMR (δ, CDCl3): 140.5 (C2), 138.3 (C1),
136.4 (C7), 134.0 (C3), 133.8 (C8), 131.5 (C6), 129.1 (C4), 128.8
(C10), 128.7 (C9), 126.6 (C5). IR (KBr, cm−1): 2552 (m, νS−H). EI-MS:
m/z 338.4 ([M]+). Mp: 91−95 °C.
Data for AsS2H2.
In solution, complex 2 undergoes slow isomerization to trans-
[Pd{(AsS)-κ2S,As}2] (3). 3 was separated as light-red crystals from a
CH2Cl2 solution of 2 after standing for 1 week at room temperature.
Data for 3. Anal. Calcd for C36H28As2PdS2 (781.00)·1/4CH2Cl2: C,
54.27; H, 3.58. Found: C, 54.37; H, 3.73. 1H NMR (δ, CDCl3): 7.70−
7.64 (m, 8H, aryl-H), 7.45−7.40 (m, 10H, aryl-H), 7.24−7.11 (m, 8H,
aryl-H), 6.98 (t, JHH = 7.5 Hz, 2H, aryl-H). IR (KBr, cm−1): 3051
3
1H NMR (δ, CDCl3): 7.41−7.36 (m, 5H, aryl-H), 7.31−7.29 (m, 2H,
(m), 2961 (w), 1568 (vs), 1548 (m), 1482 (s), 1439 (vs), 1423 (vs),
1307 (w), 1261 (m), 1242 (m), 1184 (m), 1158 (m), 1083 (vs), 1032
(s), 1000 (m), 803 (m), 738 (vs), 718 (m), 468 (vs), 435 (m). EI-MS:
m/z 781.0 ([M]+). Mp: 334−336 °C.
3
3
aryl-H), 7.23 (t, JHH = 8 Hz, 2H, aryl-H), 7.08 (t, JHH = 8 Hz, 2H,
3
aryl-H), 6.85 (d, JHH = 8 Hz, 2H, aryl-H), 3.7 (s, 2H, SH). 13C{1H}
NMR (δ, CDCl3): 139.6 (C2), 137.3 (C1), 136.6 (C7), 134.07 (C3),
134.03 (C8), 131.7 (C6), 129.4 (C4), 129.0 (C10), 128.9 (C9), 126.8
(C5). IR (KBr, cm−1): 2564 (m, νS−H). EI-MS: m/z 370.0 ([M]+). Mp:
85−88 °C.
Synthesis of cis-[Pt{(AsS)-κ2S,As}2] (4) and Formation of
[{PtI(1-AsPh2-μ-2-S-C6H4-κ2S,As)}3] (5). a. From [PtI2(cod)] and
AsSH. A solution of AsSH (0.34 g, 1 mmol) and NEt3 (1 mmol) in
methanol (20 mL) was added to a suspension of [PtI2(cod)] (0.28 g,
0.5 mmol) in methanol (20 mL). The reaction mixture was heated to
reflux for 3 h to give a yellow solution and a yellow precipitate, which
was separated by filtration, washed with methanol, and dried in a
vacuum. Yield: 0.33 g. Recrystallization from CH2Cl2/MeOH at 8 °C
yielded yellow crystals of 4. A few crystals of 5 were also isolated from
the CH2Cl2/MeOH solution. Complex 5 was characterized by X-ray
crystallography, IR spectroscopy, and fast atom bombardment mass
spectrometry (FAB-MS). The amount of pure substance was
insufficient for other characterization methods.
Data for AsS3H3.
1H NMR (δ, CDCl3): 7.43 (d, 3JHH = 8 Hz, 3H, aryl-H), 7.23 (t, 3JHH
=
=
3
3
8 Hz, 3H, aryl-H), 7.09 (t, JHH = 8 Hz, 3H, aryl-H), 6.83 (d, JHH
8 Hz, 3H, aryl-H), 3.74 (s, 3H, SH). 13C{1H} NMR (δ, CDCl3): 138.7
(C2), 136.9 (C1), 134.0 (C3), 131.9 (C6), 129.6 (C4), 125.0 (C5). IR
(KBr, cm−1): 2531 (m, νS−H). EI-MS: m/z 402.2 ([M]+). Mp: 117−
121 °C.
b. From K2[PtCl4] and AsSH. A solution of AsSH (0.11 g, 0.34
mmol) and NEt3 (0.34 mmol) in methanol (20 mL) was added to a
suspension of K2[PtCl4] (0.07 g, 0.17 mmol) in methanol (20 mL).
The reaction mixture was heated to reflux for 1 h and stirred at room
temperature overnight. The yellow precipitate formed was separated
by filtration, washed with methanol, and dried in a vacuum.
Crystallization from CH2Cl2/MeOH at 8 °C yielded yellow crystals
of 4. Yield: 0.11 g, 0.13 mmol (74%).
Synthesis of trans-[Ni{(AsS)-κ2S,As}2] (1). A solution of
NiCl2·6H2O (0.08 g, 0.34 mmol) in methanol (5 mL) was added to
a solution of AsSH (0.24 g, 0.71 mmol) and triethylamine (0.07 g,
0.71 mmol) in methanol (20 mL). The reaction mixture was heated to
reflux for 2 h and then stirred overnight. The green precipitate formed
was separated by filtration and washed with a small quantity of
methanol. Green crystals of 1 were obtained from a CH2Cl2/MeOH
Data for 4. Anal. Calcd for C36H28As2PtS2 (869.66): C, 49.72; H,
3.25. Found: C, 49.40; H, 3.51. 1H NMR (δ, CDCl3): 7.77 (d, 3JHH
8 Hz, 2H, aryl-H), 7.28 (m, 4H, aryl-H), 7.20 (d, JHH = 8 Hz, 8H,
=
3
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aryl-H), 7.14−7.05 (m, 12H, aryl-H), 6.82 (t, 3JHH = 8 Hz, 2H, aryl-H).
IR (KBr, cm−1): 3048 (m), 2988 (w), 1952 (w), 1878 (w), 1812 (w),
1570 (s), 1547 (m), 1480 (s), 1438 (vs), 1422 (vs), 1306 (m), 1267
(m), 1242 (s), 1182 (w), 1158 (m), 1123 (w), 1091 (s), 1080 (vs),
1037 (m), 1024 (m), 998 (m), 915 (w), 852 (w), 807 (w), 734 (vs),
720 (m), 690 (vs), 656 (w), 616 (w), 504 (w), 473 (vs), 449 (m),
435 (s). EI-MS: m/z 869 ([M]+). Mp: 381 °C.
1
The H NMR spectra for 1−4 show only signals of the
aromatic rings. The absence of the S−H vibration at about
2550 cm−1 in the IR spectra indicates that deprotonation of the
thiol has occurred and that the ligands are coordinated in their
anionic form. Electron impact mass spectrometry (EI-MS)
spectra exhibit the signal corresponding to the molecular ion
peak with the appropriate isotopic distribution.
Data for 5. IR (KBr, cm−1): 3051 (m), 2963 (s), 1960 (w), 1889
(w), 1814 (w), 1618 (w), 1570 (s), 1481 (s), 1440 (vs), 1424 (s),
1308 (w), 1262 (vs), 1182 (m), 1157 (m), 1093 br (vs), 1124 br (vs),
866 (m), 805 br (vs), 738 (vs), 692 (vs), 616 (w), 550 (w), 502 (w),
472 (vs), 437 (m), 405 (w). FAB-MS: m/z 1979.2 ([M]+), 1851.5
([M − I]+).
Besides mononuclear platinum complex 4, a few dark-orange
crystals of another product were isolated from the 2:1 reaction
of AsSH with [PtI2(cod)]. These were identified by X-ray
structure analysis as trimeric platinum complex 5 (Figure 1).
RESULTS AND DISCUSSION
■
The new ligands containing both thiol and arsanyl groups were
prepared by lithiation−electrophilic substitution procedures.12,13
Treatment of THF solutions of lithium 2-lithiobenzenethiolate
(1-Li-2-SLi-C6H4) at −78 °C with the appropriate electrophile
gives, after acidic workup, the 2-mercaptophenyl derivatives as
white solids, which are relatively air-stable in the solid state
(Scheme 1).
Figure 1. Schematic drawing of [{Pt(I)L}3], L = AsS− (5).
Attempts to obtain exclusively the trinuclear complex by a
1:1 reaction of AsSH with [PtI2(cod)] led to the formation of
the bis-chelate 4 and only a very small amount of orange
crystals of trimer 5 (Figure 1). A similar reaction was observed
for 1-P(Biph)-2-SHC6H4 (Biph = 1,1′-biphenyl-2,2′-diyl) with
[PtI2(cod)], which gave cis-[Pt{(1-P(Biph)-2-S-C6H4)-κ2S,P}2]
and small amounts of the trinuclear complex [{PtI(1-P(Biph)-
μ-2-S-C6H4-κ2S,P)}3].31 Subsequently, it was found that the 1:1
reaction of the heterotopic P,SAs ligand 1-PPh2-2-SAsPh2-C6H4
with [PtI2(cod)] resulted in cleavage of the As−S bond and
coordination of the resulting phosphanylthiolato ligand
(SC6H4-2-PPh2)− with formation of a similar trimeric
compound to 5. It was shown that this trimer is not formed
as an intermediate on the way to formation of the bis-chelate,
but it is (besides the cis bis-chelates) the major product formed.
The proposed mechanism for the formation of this trimer
involves generation of trinuclear species [(cis-Pt{(μ-S-SC6H4-2-
PPh2)-κ2S,P}2)−PtI2−PtI{(μ-S-SC6H4-2-PPh2)-κ2S,P}], which
rearranges with formation of the trimer [PtI{(μ-S-SC6H4-2-
PPh2)-κ2S,P}]3.32
Scheme 1. Synthesis of Arsanylarylthiols
1
AsSH, AsS2H2, and AsS3H3 show signals in the H NMR
spectra in the range of 6.8−7.4 ppm corresponding to the
aromatic protons and a singlet around 3.7 ppm assigned to the
SH protons.
Treatment of AsSH with NiCl2·6H2O, Na2[PdCl4], and
[PtI2(cod)] in a 2:1 ratio and in the presence of NEt3 (Scheme
2) led to the corresponding square-planar nickel, palladium,
and platinum complexes 1−4. Only one isomer was isolated in
the case of nickel, compound 1, and platinum, compound 4. In
the case of palladium, orange crystals were formed by slow
crystallization from CH2Cl2/MeOH and identified as 2. In
solution, 2 undergoes slow isomerization to 3, and in a few days
at room temperature, light red crystals of 3 formed. A similar
behavior was observed for the corresponding nickel, palladium,
and platinum complexes of PSH.14a,15,17,19
Molecular Structures of the Square-Planar Nickel,
Palladium, and Platinum Complexes of AsSH. Crystals of
1−4 suitable for X-ray crystallography were obtained from a
a
Scheme 2. Syntheses of the Nickel, Palladium, and Platinum Complexes of AsSH
a
(i) NiCl2·6H2O, NEt3; (ii) Na2[PdCl4] or [PtI2(cod)], NEt3.
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Table 2. Selected Bond Lengths (Å) and Angles (deg) in 1−4
compound
M−S
M−As
As−M−S
As−M−S′
S−M−S′
As−M−As′
180
98.08(2)
1
2.188(1)
2.319(1)
2.322(1)
2.314(1)
2.313(1)
2.314(1)
2.2709(4)
2.3625(6)
2.3648(6)
2.3604(6)
2.3530(7)
2.3524(7)
88.96(3)
87.30(4)
87.36(4)
86.82(3)
87.62(4)
87.62(4)
91.04(3)
174.61(4)
173.95(4)
93.18(3)
180
a
2
87.28(5)
3
180
180
98.04(3)
a
4
173.86(4)
174.33(4)
86.75(5)
a
In Figure 3 (left), the prime notation was employed, even though the corresponding atoms are not symmetry-related, to facilitate a comparison of
the related structures.
CH2Cl2/MeOH double-layer system. Selected bond lengths
and angles for 1−4 are given in Table 2. Structures of
compounds 1 and 3 or 2 and 4, respectively, are isotypic.
The molecular structure of green prisms of 1 is shown in
Figure 2.
range reported for other thiolato complexes of this type.15,16,33
The Ni−As bond length of 2.2709(4) Å is close to the
values found in other tertiary arsine complexes: 2.253(2) Å
in 1-(diphenylarsanyl)-2-(diphenylphosphanyl)ethane(o-methyl
dithiophosphate)nickel(II),34,35 2.255(1) Å in tetrakis(μ3-
sulfido)tris(η5-methylcyclopentadienyl)(triphenylarsine)-
trimolybdenum−nickel p-toluenesulfonate35, and 2.218(2) and
2.325(2) Å in (bis(o-diphenylarsinophenyl)(o-methylthiophenyl)-
arsine)bromonickel(II) perchlorate.36 The arsenic atoms are
surrounded in a slightly distorted tetrahedral fashion with bond
angles between 103.04(2)° and 119.19(1)°.
The molecular structure of 2 (Figure 3, left) reveals strong
interactions between the phenyl rings of the cis-diphenylar-
sanyl groups caused by the rigidity of the chelating ligand and
the square-planar coordination of palladium(II). The mole-
cules of 2 accommodate the bulky diphenylarsanyl groups by
widening the As−Pd−As′ bond angle to 98.08(2)°, reducing
the S−Pd−S′ bond angle to 87.28(5)°, and arranging the
interfering phenyl rings parallel to each other (av. phenyl−phenyl
distance 4.184 Å).
The palladium atom is in a slightly distorted square-
planar environment [As−Pd−S′ 173.95(4)° and As′−Pd−S
174.61(4)°], with this distortion being due to the cis arrange-
ment of both AsS− ligands. The bite angles of the chelate ligand
[As−Pd−S 87.30(4) and 87.36(4)°] are similar to that found
for the corresponding phosphorus-containing analogue PS−
[P−Pd−S chelate angles 87.06(3)° and 87.24(3)°]. Most bond
lengths and angles in 2 [Pd−S 2.319(1) and 2.322(1) Å and
Pd−As 2.3648(6) and 2.3625(6) Å] are not very different from
those found in cis-[Pd{(PS)-κ2S,P}2] (Pd−S 2.32 Å and Pd−P
2.28 Å).17
Figure 2. Molecular structure of 1.
The nickel atom is located on a crystallographic inversion
center and is coordinated by two sulfur atoms and two arsenic
atoms, giving a strictly planar arrangement (As−Ni−As′ 180°
and S−Ni−S′ 180°). The sulfur atoms are in a trans disposition,
and the As−Ni−S′ bond angles between the adjacent ligands
are close to 90° (Table 2). The chelate angle S−Ni−As
[88.96(3)°] and the Ni−S bond length of 2.188(1) Å are in the
Figure 3. Molecular structures of 2 (left) and 3 (right).
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Figure 4. Molecular structures of the trinuclear complex 5 and structure fragment showing the central Pt3S3 six-membered ring and the square-planar
coordination around the platinum atoms.
Table 3. Selected Bond Lengths (Å) and Angles (deg) in 5
Pt1−S1
Pt2−S2
Pt3−S3
Pt1−S3
Pt2−S1
Pt3−S2
Pt1−As1
Pt2−As2
Pt3−As3
Pt1−I1
Pt2−I2
Pt3−I3
2.306(2)
2.284(2)
2.292(2)
2.398(2)
2.344(2)
2.365(2)
2.3343(8)
2.340(1)
2.3455(9)
2.6021(7)
2.6208(7)
2.6148(7)
S1−Pt1−As1
S1−Pt1−S3
P1−Pt1−S3
S1−Pt1−I1
As1−Pt1−I1
S3−Pt1−I1
S2−Pt2−P2
S2−Pt2−S1
As2−Pt2−S1
S2−Pt2−I2
As2−Pt2−I2
S1−Pt2−I2
86.12(5)
91.95(7)
177.18(6)
172.71(6)
86.99(3)
95.01(5)
87.84(6)
83.18(7)
169.55(6)
177.58(5)
93.30(3)
95.89(5)
S3−Pt3−As3
S3−Pt3−S2
As3−Pt3−S2
S3−Pt3−I3
As3−Pt3−I3
S2−Pt3−I3
C2−S1−Pt1
C2−S1−Pt2
Pt1−S1−Pt2
C20−S2−Pt2
C20−S2−Pt3
Pt2−S2−Pt3
C38−S3−Pt3
C38−S3−Pt1
Pt3−S3−Pt1
87.36(6)
91.50(7)
175.20(5)
176.66(5)
92.30(3)
89.11(5)
107.7(3)
111.4(3)
101.43(8)
107.5(3)
104.0(3)
109.43(8)
106.3(3)
107.6(3)
98.79(8)
In solution, 2 undergoes slow isomerization to 3 (Figure 3).
In 3, the palladium atom is situated in a strictly square-planar
environment (As−Pd−As′ 180° and S−Pd−S′ 180°). The bite
angle As−Pd−S of 86.82(3)° is slightly smaller than those
found for the cis isomer 2.
central Pt3S3 ring. The fourth coordination site at platinum is
occupied by a terminally bonded iodo ligand.
The structures of several trinuclear complexes of platinum
with bridging sulfur atoms have been described;37,38 how-
ever, none contain an arsanylthiolato ligand. Geometry-related
structures were found in the platinum complex of 2-(dimethyl-
amino)ethanethiol, [{PtBr(μ-S-CH2CH2NMe2-κ2N,S)}3], which
contains a central Pt3S3 ring with nearly symmetrical Pt−S−Pt
thiolato bridges [Pt1−S1 2.255(4) Å and Pt1−S3 2.285(4) Å]38
and in trimeric complexes [{PtI(1-P(Biph)-μ-2-S-C6H4-
κ2S,P)}3]31 and [PtI{(μ-S-SC6H4-2-PPh2)-κ2S,P}]3.32
In 5, each sulfur atom is coordinated to two platinum atoms
with one shorter (trans to iodine av. 2.29 Å) and one longer
bond (trans to arsenic av. 2.37 Å; Table 3). The Pt−S bond
lengths are in the range observed for dimeric platinum(II)
complexes containing nonchelating thiolato bridges of the
type [{PtX(μ-SR′)(PR3)}2] (X = Cl, I; R = Pr, Ph; R′ = Et,
CH2CH2CMeCH2).39,40 The Pt−I bond lengths are com-
parable to those found in [{PtI(μ-SCH2CH2CMeCH2)-
(PPh3)}2] (2.62 Å).40 The distances between the platinum
atoms in 5 are all greater than 3.56 Å and thus indicate no
metal−metal bonding.
Deep-yellow prisms of 4 crystallized with one molecule of
dichloromethane in the asymmetric unit. The structure is
isotypic to that of the palladium complex 2 (Figure 3, left). The
platinum atom is in a distorted square-planar arrangement [As−
Pt−S′ 173.86(4)°, As′−Pt−S 174.33(4)°] (Table 2). The arsenic
atoms are in a cis position, and the average distance between the
phenyl rings in the molecule is 4.177 Å. The Pt−S (av. 2.31 Å)
and Pt−As (av. 2.35 Å) bond distances and the bite angle As−Pt−
S of 87.62(4)° are similar to those found in the methyl-substituted
analogue trans-[Pt{(1-AsMe2-2-S-C6H4)-κ2S,As}2] [Pt−S
2.308(3) Å and Pt−As 2.354(1) Å; As−Pt−S 87.7°)7f and in
the phosphorus analogue cis-[Pt{(PS)-κ2S,P}2] (2.31 Å).19
Molecular Structure of 5. Trinuclear complex 5 contains a
six-membered Pt3S3 ring with a twist−boat conformation and
nonsymmetrical Pt−S−Pt thiolato bridges (Figure 4 and Table 3).
Each ligand chelates one platinum atom to give a PtSC2As
ring. The sulfur atoms bridge the platinum atoms to give a
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The geometry at sulfur is distorted trigonal pyramidal
[i.e., C2−S1−Pt1 107.7(3)°, C2−S1−Pt2 111.4(3)°, and
Pt1−S1−Pt2 101.43(8)°]. The Pt−As bond lengths and the
chelate angle at the platinum atom in 5 are similar to those found
in the monomeric complex 4.
Theoretical Study of Cis−Trans Isomerism. Density
functional theory calculations predict practically isoenergetic cis
and trans isomers for [Ni{(AsS)-κ2S,As}2] (Table 4). However,
Table 4. Zero-Point-Energy-Corrected Relative Energies
(kJ mol−1) of All Investigated Structures [M{(AsS)-κ2S,As}2]
(M = Ni, Pd, Pt)
cis-[Ni{(AsS)-κ2S,As}2]
2.8
0.0
1
[Ni{(AsS)-κ2S,As}2] (triplet)
78.8
0.0
2
3
2.2
Figure 5. Optimized [Pd{(AsS)-κ2S,As}2] intermediates (I and II) and
transition state (TS) along the dissociative cis/trans isomerization
pathway. The distances between the atoms involved in the Pd−η3-
AsPh agostic interactions are also shown (in Å).
[Pd{(AsS)-κ2S,As}2] (triplet)
150.7
116.1
139.8
91.6
0.0
I
TS
II
4
intermediate II; that is, the balance of the cis/trans isomer-
ization reaction is shifted toward the trans isomer.
trans-[Pt{(AsS)-κ2S,As}2]
10.1
182.7
[Pt{(AsS)-κ2S,As}2] (triplet)
CONCLUSIONS
■
Reactions of the new heteropolytopic arsanylthiolato ligand
AsSH with group 10 metal(II) complexes in a 2:1 ratio afforded
square-planar complexes [M{(1-AsPh2-2-S-C6H4)-κ2S,As}2]
([M{(AsS)-κ2S,As}2], M = Ni, Pd, Pt). Only one isomer was
isolated in the case of nickel and platinum, 1 and 4, whereas for
palladium, the initially formed cis product 2 undergoes slow
isomerization to 3 in solution. Besides mononuclear platinum
bis-chelate complex 4, the unexpected trinuclear complex 5 is
also formed.
the trans isomer 1 is slightly favored over the corresponding cis
isomer in terms of relative energy. This trend is also in
agreement with experimental observations. For [Pt{(AsS)-
κ2S,As}2], the cis isomer 4 is thermodynamically favored over
the corresponding trans isomer (Table 4). This explains why
only 4 has been obtained experimentally. For [Pd{(AsS)-
κ2S,As}2], the cis and trans isomers are again predicted to be
isoenergetic (Table 4). To explain the observed cis-to-trans
isomerization, the dissociative mechanism suggested by Romeo
and co-workers41 was investigated for the palladium complexes,
along with a square planar−tetrahedral (triplet)−square planar
pathway. The singlet−triplet splitting energies predict an
increasing trend for the isomerization barriers, in the order
Ni < Pd < Pt (Table 4). The same trends were also predicted
for the related complexes [M{(PBiph)-κ2S,P}2] (M = Ni, Pd, Pt).
However, the π−π interactions between two Biph moieties are
much stronger than those between two phenyl rings, as
evidenced by experiment and theory.31 The dissociative cis/
trans isomerization mechanism of [Pd{(AsS)-κ2S,As}2] involves
a Y-shaped transition state (TS in Figure 5) lying above 2 by
139.8 kJ mol−1 in terms of relative energy (Table 4). This
isomerization barrier is lower than the relative energy of the
triplet isomer. Thus, the dissociative mechanism is slightly
favored over the square planar−tetrahedral−square planar
pathway. Following the normal mode associated with the
imaginary frequency of TS leads to the T-shaped cis- and trans-
like intermediates I and II, respectively (Figure 5). Both
intermediates are characterized by a Pd−η3-AsPh agostic
interaction similar to the η3-metal−benzyl linkage described
by Guido et al.41a Natural bond orbital analysis42 of I and II
revealed donation of the electron density from the As−C
σ bond to an unoccupied p orbital at Pd as the main contribution
to the stabilizing Pd−η3-AsPh agostic interaction. Additionally,
one of the πC−C bonding orbitals of the phenyl ring also
donates electron density to the p orbital at Pd. The cis-like
intermediate I lies at a higher relative energy than the trans-like
ASSOCIATED CONTENT
* Supporting Information
■
S
X-ray crystallographic data of complexes 1−5 in CIF format,
Table S1 with the computed energies for 1−4, and optimized
Cartesian coordinates. This material is available free of charge
via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
Corresponding Author
*E-mail: hey@uni-leipzig.de.
■
Notes
The authors declare no competing financial interest.
§Deceased as of Dec 2009. He will be missed.
ACKNOWLEDGMENTS
■
We thank Umicore AG & Co. KG, Hanau, Germany, for a
generous donation of PdCl2 and H2[PtCl6]·6H2O. We
gratefully acknowledge financial support from the International
Postgraduate Programme (IPP “Research at the Frontiers of
Chemistry”) at Universitat Leipzig (to A.H.), as well as financial
̈
support provided by programs cofinanced by the Sectoral
Operational Program Human Resources Development, Con-
tract POSDRU 6/1.5/S/3, “Doctoral studies: through science
towards society” (to I.S. and M.B.S.) and from the Deutscher
Akademischer Austausch Dienst (DAAD scholarship for I.S.,
SOE programme).
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(12) (a) Figuly, G. D.; Loop, C. K.; Martin, J. C. J. Am. Chem. Soc.
1989, 111, 654. (b) Block, E.; Eswarakrishnan, V.; Gernon, M.; Ofori-
Okai, G.; Saha, C.; Tang, K.; Zubieta, J. J. Am. Chem. Soc. 1989, 111,
658. (c) Smith, K.; Lindsay, C. M.; Pritchard, G. J. J. Am. Chem. Soc.
REFERENCES
■
(1) (a) Yuki, M.; Miyake, Y.; Nishibayashi, Y. Organometallics 2010,
29, 5994. (b) He, L.-P.; Hong, M.; Li, B.-X.; Liu, J.-Y.; Li, Y.-S. Polymer
2010, 51, 4336. (c) Fernandez, P.; Sousa-Pedrares, A.; Romero, J.;
Duran, M. L.; Sousa, A.; Perez-Lourido, P.; Garcia-Vazquez, J. A. Eur. J.
Inorg. Chem. 2010, 814. (d) Ye, S.; Neese, F.; Ozarowski, A.; Smirnov,
D.; Krzystek, J.; Telser, J.; Liao, J.-H.; Hung, C.-H.; Chu, W.-C.; Tsai,
Y.-F.; Wang, R.-C.; Chen, K.-Y.; Hsu, H.-F. Inorg. Chem. 2010, 49,
977−988. (e) Valean, A.-M.; Gomez-Ruiz, S.; Loennecke, P.; Silaghi-
Dumitrescu, I.; Silaghi-Dumitrescu, L.; Hey-Hawkins, E. New J. Chem.
2009, 33, 1771. (f) Kraikivskii, P. B.; Frey, M.; Bennour, H. A.;
Gembus, A.; Hauptmann, R.; Svoboda, I.; Fuess, H.; Saraev, V. V.;
Klein, H.-F. J. Organomet. Chem. 2009, 694, 1869. (g) Valean, A. M.;
Gomez-Ruiz, S.; Lonnecke, P.; Silaghi-Dumitrescu, I.; Silaghi-
Dumitrescu, L.; Hey-Hawkins, E. Inorg. Chem. 2008, 47, 11284.
(h) Chiou, T.-W.; Liaw, W.-F. Inorg. Chem. 2008, 47, 7908.
(i) Gomez-Benitez, V.; Toscano, R. A.; Morales-Morales, D. Inorg.
Chem. Commun. 2007, 10, 1. (j) She, L.; Li, X.; Sun, H.; Ding, J.; Frey,
M.; Klein, H.-F. Organometallics 2007, 26, 566. (k) Lee, C.-M.;
Chuang, Y.-L.; Chiang, C.-Y.; Lee, G.-H.; Liaw, W.-F. Inorg. Chem.
2006, 45, 10895. (l) Chu, W.-C.; Wu, C.-C.; Hsu, H.-F. Inorg. Chem.
2006, 45, 3164. (m) Gorol, M.; Roesky, H. W.; Noltemeyer, M.;
Schmidt, H.-G. Eur. J. Inorg. Chem. 2005, 4840. (n) Dilworth, J. R.;
Wheatley, N. Coord. Chem. Rev. 2000, 199, 89. (o) Cabeza, J. A.;
Martínez-García, M. A.; Riera, V.; Ardura, D.; Garcia-Granda, S. Eur. J.
Inorg. Chem. 2000, 499.
(2) (a) Farina, V.; Krishnan, B. J. Am. Chem. Soc. 1991, 113, 9585.
(b) Amatore, C.; Bahsoun, A. A.; Jutand, A.; Meyer, G.; Ntepe, A. N.;
Ricard, L. J. Am. Chem. Soc. 2003, 125, 4212. (c) Johnson, C. R.;
Braun, M. P. J. Am. Chem. Soc. 1993, 115, 11014. (d) Bedford, R. B.;
Cazin, C. S. J.; Coles, S. J.; Gelbrich, T.; Hursthouse, M. B.; Scordia, V.
J. M. Dalton Trans. 2003, 3350. (e) van der Veen, L. A.; Keeven, P. K.;
Kamer, P. C.; van Leeuwen, P. W. N. M. Chem. Commun. 2000, 333.
(f) Baber, R. A.; Collard, S.; Hooper, M.; Orpen, A. G.; Pringle, P. G.;
Wilkinson, M. J.; Wingada, R. L. Dalton Trans. 2005, 1491.
(g) Ceccarelli, S.; Piarulli, U.; Gennari, C. J. Org. Chem. 2000, 65,
6254. (h) Dai, W.-M.; Wu, A.; Wu, H. Tetrahedron: Asymmetry 2002,
13, 2187.
1989, 111, 665. (d) Hildebrand, A.; Lonnecke, P.; Silaghi-Dumitrescu,
̈
L.; Silaghi-Dumitrescu, I.; Hey-Hawkins, E. Dalton Trans. 2006, 967.
(13) Block, E.; Ofori-Okai, G.; Zubieta, J. J. Am. Chem. Soc. 1989,
111, 2327.
(14) (a) Benefiel, A.; Roundhill, D. M.; Fultz, W. C.; Rheingold, A. L.
Inorg. Chem. 1984, 23, 3316. (b) Dutta, R. L.; Meek, D. W.; Busch, D.
H. Inorg. Chem. 1970, 9, 1215. (c) Eller, P. G.; Riker, J. M.; Meek, D.
W. J. Am. Chem. Soc. 1973, 95, 3540.
(15) Kim, J. S.; Reibenspies, J. H.; Darensbourg, M. Y. J. Am. Chem.
Soc. 1996, 118, 4115.
(16) Block, E.; Ofori-Okai, G.; Kang, H.; Zubieta, J. Inorg. Chim. Acta
1991, 188, 7.
́
(17) Real, J.; Prat, E.; Polo, A.; Alvarez-Larena, A.; Piniella, J. F. Inorg.
Chem. Commun. 2000, 3, 221.
(18) (a) Roundhill, D. M.; Roundhill, S. G. N.; Beaulieu, W. B.;
Bagchi, U. Inorg. Chem. 1980, 19, 3365. (b) Benefiel, A.; Roundhill, D.
M. Inorg. Chem. 1986, 25, 4027. (c) Dilworth, J. R.; Hutson, A. J.;
Zubieta, J.; Chen, Q. Transition Met. Chem. 1994, 19, 61.
(19) Canseco-Gonzalez, D.; Gomez-Benitez, V.; Hernandez-Ortega,
́ ́ ́
S.; Toscano, R. A.; Morales-Morales, D. J. Organomet. Chem. 2003,
679, 101.
(20) Blicke, F. F.; Smith, F. D. J .Chem. Soc. 1929, 51, 1558.
(21) Houben−Weyl Methoden der Organischen Chemie. Metal-
lorganische Verbindungen von As, Sb, und Bi; Georg Thieme Verlag:
Stuttgart, Germany, 1978; p 174.
(22) Cotton, F. A. Inorg. Synth. 1972, 13, 48.
(23) Brauer, G. Handbuch der Praparativen Anorganischen Chemie;
̈
Band III, Ferdinand Enke Verlag: Stuttgart, Germany, 1981.
(24) (a) SMART: Area-Detector Software Package; Siemens Industrial
Automation, Inc.: Madison, WI, 1993. (b) SAINT: Area-Detector
Integration Software, version 6.01; Siemens Industrial Automation, Inc.:
Madison, WI, 1999. (c) Sheldrick, G. M. SADABS, Program for Scaling
and Correction of Area-detector Data; Universitat Gottingen: Gottingen,
̈
̈
̈
Germany, 1997. (d) SHELX includes SHELXS97 and SHELXL97:
Sheldrick, G. M. Acta Crystallogr. 2008, A64, 112. (e) ORTEP3 for
Windows: Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
(3) Moldovan, N.; Lonnecke, P.; Silaghi-Dumitrescu, I.; Silaghi-
Dumitrescu, L.; Hey-Hawkins, E. Inorg. Chem. 2008, 47, 1524.
̈
(25) GEMINI: Sparks, R. A. Bruker AXS: Madison, WI, 1999.
(26) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.;
Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci,
B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian,
H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada,
M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.;
Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.;
Montgomery, J. A., Jr.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.;
Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi,
R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar,
S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J.
E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.;
Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.;
Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.;
Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A.
D.; Farkas, O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J.
Gaussian 09, revision A.02; Gaussian, Inc.: Wallingford, CT, 2009.
(27) (a) Zhao, Y.; Truhlar, D. Theor. Chem. Acc. 2008, 120, 215.
(b) Zhao, Y.; Truhlar, D. Acc. Chem. Res. 2008, 41, 157.
(4) Fischer-Fodor, E.; Moldovan, N.; Virag, P.; Soritau, O.; Brie, I.;
Lonnecke, P.; Hey-Hawkins, E.; Silaghi-Dumitrescu, L. Dalton Trans.
̈
2008, 6393.
(5) Miklas
Virag, P.; Schrepler, M. P.; Miklas
Hawkins, E. Eur. J. Med. Chem. 2012, 49, 41.
(6) Hildebrand, A.; Sarosi, M. B.; Lonnecke, P.; Silaghi-Dumitrescu,
́
ova, N.; Fischer-Fodor, E.; Lonnecke, P.; Tomuleasa, C. I.;
̌
́
̈
́ ̌
, R.; Silaghi-Dumitrescu, L.; Hey-
́
̈
L.; Hey-Hawkins, E. Rev. Roum. Chem. 2010, 55, 885.
(7) (a) Livingstone, S. E. J. Chem. Soc. 1958, 4222. (b) Chiswell, B.;
Livingstone, S. E. J. Chem. Soc. 1960, 1071. (c) Stephenson, N. C. J.
Inorg. Nucl. Chem. 1962, 24, 791. (d) Duckworth, V. F.; Stephenson,
N. C. Inorg. Chem. 1969, 8, 1661. (e) Beale, J. P.; Stephenson, N. C.
Acta Crystallogr. 1970, B26, 1655. (f) Beale, J. P.; Stephenson, N. C.
Acta Crystallogr. 1971, B27, 73.
(8) (a) Miller, E. M.; Shaw, B. L. J. Chem. Soc., Dalton Trans. 1974,
480. (b) Lindoy, L. F.; Livingstone, S. E.; Lockyer, T. N. Inorg. Chem.
1967, 6, 652. (c) Lindoy, L. F.; Livingstone, S. E.; Lockyer, T. N. Aust.
J. Chem. 1967, 20, 471. (d) Lockyer, T. N. Aust. J. Chem. 1974, 27,
259. (e) Harbron, S. K.; Higgins, S. J.; Hope, E. G.; Kemmit, T.;
Levason, W. Inorg. Chim. Acta 1987, 130, 43. (f) Fitzpatrick, M. G.;
Hanton, L. R.; Henderson, W.; Kniebone, P.; Levy, E. G.; McCaffrey,
L. J.; McMorran, D. A. Inorg. Chim. Acta 1988, 281, 101.
(9) Tsang, W. S.; Meek, D. W.; Wojcicki, A. Inorg. Chem. 1968, 7,
1263.
(28) (a) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 270.
(b) Couty, M.; Hall, M. B. J. Comput. Chem. 1996, 17, 1359.
(29) Hehre, W. J.; Pople, J. A. J. Chem. Phys. 1972, 56, 2257.
(30) (a) Peng, C.; Schlegel, H. B. Israel J. Chem. 1993, 33, 449.
(b) Peng, C.; Ayala, P. Y.; Schlegel, H. B.; Frisch, M. J. J. Comput.
Chem. 1996, 17, 49.
(10) Dyer, G.; Workman, M. O.; Meek, D. W. Inorg. Chem. 1967, 6,
(31) Hildebrand, A.; Sar
Sarosi, M. B.; Silaghi-Dumitrescu, I.; Hey-Hawkins, E. Dalton Trans.
2012, 41, 7729.
́
osi, I.; Lonnecke, P.; Silaghi-Dumitrescu, L.;
̈
1404.
(11) Hildebrand, A.; Lonnecke, P.; Silaghi-Dumitrescu, L.; Hey-
Hawkins, E. Dalton Trans. 2008, 4639.
́
̈
7132
dx.doi.org/10.1021/ic300002p | Inorg. Chem. 2012, 51, 7125−7133

Inorganic Chemistry
Article
(32) Sar
Hey-Hawkins, E. Dalton Trans. 2012, 41, 5326.
́
(33) Perez-Lourido, P.; Romero, J.; Garcia-Vasquez, J. A.; Sousa, A.;
́
osi, I.; Hildebrand, A.; Lonnecke, P.; Silaghi-Dumitrescu, L.;
̈
́
Zubieta, J.; Maresca, K. Polyhedron 1998, 17, 4457.
(34) Gastaldi, L.; Porta, P.; Tomlinson, A. A. G. J. Chem. Soc., Dalton
Trans. 1974, 1424.
(35) Herbst, K.; Zanello, P.; Corsini, M.; D’Amelio, N.; Dahlenburg,
L.; Brorson, M. Inorg. Chem. 2003, 42, 974.
(36) Mathew, M.; Palenik, G. J.; Dyer, G.; Meek, D. W. Chem.
Commun. 1972, 379.
(37) (a) Sellmann, D.; Haußinger, D.; Heinemann, F. W. Eur. J.
̈
Inorg. Chem. 1999, 1715. (b) Ghilardi, C. A.; Midollini, S.; Orlandini,
A.; Scapacci, G.; Vacca, A. J. Organomet. Chem. 1993, 461, C4.
(c) Chou, J. H.; Kanatzidis, M. G. Inorg. Chem. 1994, 33, 5372.
(d) Davidson, Y. Y.; Chang, S. Ch.; Norman, R. E. J. Chem. Soc., Dalton
Trans. 1995, 77.
(38) Capdevila, M.; Clegg, W.; Gonzal
Soc., Dalton Trans. 1992, 173.
́
es-Duarte, P.; Mira, I. J. Chem.
(39) Hall, M. C.; Jarvis, J. A. J.; Kilbourn, B. T.; Owston, P. G. J.
Chem. Soc., Dalton Trans. 1972, 1544.
(40) Abel, E. W.; Evans, D. G.; Koe, J. R.; Hursthouse, M. B.; Mazid,
M.; Mahon, M. F.; Molloy, K. C. J. Chem. Soc., Dalton Trans. 1990,
1697.
(41) (a) Guido, E.; D’Amico, G.; Russo, N.; Sicilia, E.; Rizzato, S.;
Albinati, A.; Romeo, A.; Plutino, M. R.; Romeo, R. Inorg. Chem. 2011,
50, 2224. (b) Romeo, R.; D’Amico, G.; Sicilia, E.; Russo, N.; Rizzato,
S. J. Am. Chem. Soc. 2007, 129, 5744.
(42) Reed, A. E.; Curtiss, L. A.; Weinhold, F. Chem. Rev. 1988, 88,
899.
7133
dx.doi.org/10.1021/ic300002p | Inorg. Chem. 2012, 51, 7125−7133