Synthesis of an acyclic diselenodithioether ligand tethered with bulky substituents and its application to the synthesis of a distorted octahedral palladium(II) complex

Article abstract of DOI:10.1002/hc.20339

A new o-phenylene-bridged diselenodithioether ligand tethered with an extremely bulky substituent, 2,4,6-tris[bis(trimethylsilyl)methyljphenyl (Tbt) group, at both terminal selenium atoms, [TbtSe(o-phenylene)S] ₂(o-phenylene) (3), was synthesiz

Full text of DOI:10.1002/hc.20339

Heteroatom Chemistry
Volume 18, Number 5, 2007
Synthesis of an Acyclic Diselenodithioether
Ligand Tethered With Bulky Substituents and
Its Application to the Synthesis of a Distorted
Octahedral Palladium(II) Complex
Nobuhiro Takeda, Toru Isobe, and Norihiro Tokitoh
Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
Received 27 October 2006
arrangement around the palladium metal and the
ABSTRACT: A new o-phenylene-bridged diseleno-
two terminal selenium atoms of 3 weakly coordinate
to the palladium center at the axial positions. The
dithioether ligand tethered with an extremely
bulky
substituent,
2,4,6-tris[bis(trimethylsilyl)-
AIM calculations also indicated the existence of the
interaction between palladium and selenium atoms
in the crystalline state. On the other hand, the 77Se
NMR spectrum suggests that there are no or very weak
interactions between the palladium and selenium
methyl]phenyl (Tbt) group, at both terminal selenium
atoms, [TbtSe(o-phenylene)S]2(o-phenylene) (3),
was synthesized by taking advantage of the reaction
of TbtSeSeTbt (4) with 1,2-diiodobenzene using
Cu2O in 2,4,6-trimethylpyridine followed by the
successive coupling reaction of the resulting bulky
o-iodophenylselenide (5) with 1,2-benzenedithiol.
Complexation of 3 with Na2PdCl4 gave the corre-
sponding dichloropalladium(II) complex, [PdCl2(3)]
(6). The X-ray structural analysis of 6 indicated that
the central palladium metal is in a distorted octahe-
dral environment, where the two inner sulfur atoms
of 3 and the two chlorine atoms form a square planar
ꢀ
C
atoms of 3 in solution.
2007 Wiley Periodicals, Inc.
Heteroatom Chem 18:549–556, 2007; Published online in
Wiley InterScience (www.interscience.wiley.com). DOI
10.1002/hc.20339
INTRODUCTION
It has been known that palladium(II) complexes
generally have square planar geometry around
the palladium atom, and there are very few
examples for six-coordinate complexes of palla-
dium(II). Cyclic polythioether (crown thioether) lig-
ands such as 1,4,7-trithiacyclononane (9S3) [1,2],
1,4,7,10,13,16-hexathiacyclooctadecane (18S6) [3],
and 1,4,7-trithiacyclodecane (10S3) [4,5], reportedly
complexed with a palladium(II) metal to give the
corresponding five- or six-coordinate palladium(II)
complexes, in which the four sulfur atoms are ar-
ranged in a square planar fashion around the pal-
ladium(II) atom and the other sulfur atoms weakly
coordinate to the palladium(II) atom [Pd · · · S: 2.96–
Correspondence to: Norihiro Tokitoh; e-mail: tokitoh@boc.
kuicr.kyoto-u.ac.jp. Present address of Nobuhiro Takeda: Depart-
ment of Chemistry and Chemical Biology, Graduate School of
Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma
376-8515, Japan.
Contract grant sponsor: Grants-in-Aid for COE Research on
Elements Science.
Contract grant number: 12CE2005.
Contract grant sponsor: Creative Scientific Research, Ministry
of Education, Culture, Sports, Science, and Technology, Japan.
Contract grant number: 17GS0207.
Contract grant sponsor: Young Scientist (B), Ministry of Edu-
cation, Culture, Sports, Science, and Technology, Japan.
Contract grant number: 15750031.
Contract grant sponsor: 21st Century COE Program on Kyoto
University Alliance for Chemistry, from the Ministry of Educa-
tion, Culture, Sports, Science and Technology, Japan.
˚
c
ꢀ
2007 Wiley Periodicals, Inc.
3.27 A] at the axial positions.
549

550 Takeda, Isobe, and Tokitoh
CHART 1
SCHEME 1 Synthesis of diselenodithioether ligand 3.
Recently, we have reported the synthesis of a
new type of tetrathioether ligand 1 tethered with
two 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt)
groups at both terminal sulfur atoms (Chart 1) [6].
Tbt group is an extremely bulky substituent and
known to be effective to the stabilization of a va-
riety of highly reactive species [7–9]. In addition, we
have found that dichloropalladium complex 2 bear-
ing the tetrathioether ligand 1 has a distorted octa-
hedral structure, where the two inner sulfur atoms of
1 and the two chlorine atoms form a square planar
arrangement around the palladium metal and the
two terminal sulfur atoms of 1 weakly coordinate to
the palladium center at the axial positions [6].
The coordination chemistry of selenoethers has
also been studied extensively [10–12], and sele-
noethers have an advantage that the 77Se NMR spec-
troscopic analysis of their transition metal com-
plexes give much information about the coordinate
bonds between the selenium atom and the metal
center. This advantageous feature of selenoether lig-
ands prompted us to synthesize a selenium analog
of tetrathioether 1.
LiAlH4, H2O, and air (Scheme 1). Coupling reaction
of 4 with 1,2-diiodobenzene using Cu2O in refluxing
2,4,6-trimethylpyridine [6,13] afforded sulfide 5 in
63% yield. Further coupling reaction of 5 with 0.5
equivalents of 1,2-benzenedithiol under the condi-
tions similar to those for the transformation of 4 to
5 gave the expected diselenodithioether 3 in a good
yield.
Structure of Diselenodithioether Ligand 3
Diselenodithioether ligand 3 was characterized on
the basis of the 1H, 13C, and 77Se NMR spectro-
scopic data together with the results of MS measure-
ment and elemental analysis. The molecular struc-
ture of 3 in the crystalline state was definitively
determined by X-ray structural analysis. Figure 1
shows the ORTEP drawing of 3, and the selected
bond lengths, angles, and torsion angles are sum-
marized in Table 1. All the C S and C Se bond
lengths of 3 show usual values for the C S and
C Se single bonds, respectively [14]. The bond an-
gles around the selenium atoms are slightly smaller
than those around the sulfur atoms. It is notewor-
thy that C1 Se1 C28 and C45 Se2 C46 planes in
In this article, we report the synthesis of a new
bulky diselenodithioether ligand 3 having two inner
sulfur atoms and two terminal selenium atoms and
its application to the synthesis of the corresponding
highly coordinated palladium(II) complex.
RESULTS AND DISCUSSION
Synthesis of a Diselenodithioether Ligand 3
The synthetic strategy for the diselenodithioether
ligand 3 consists of the successive coupling re-
actions of an iodobenzene derivative with a dise-
lenide or thiol derivative in the presence of Cu2O
in 2,4,6-trimethylpyridine as well as that for the
tetrathioether ligand 1. Tbt-substituted diselenide 4
was synthesized by the reaction of TbtLi, prepared
by the reaction of TbtBr and tert-butyllithium, with
elemental selenium, followed by the treatment with
FIGURE 1 ORTEP drawing of 3 with thermal ellipsoids (50%
probability). Hydrogen atoms, trimethylsilyl groups, and a sol-
vent molecule (chloroform) were omitted for clarity.
Heteroatom Chemistry DOI 10.1002/hc

Acyclic Diselenodithioether Ligand With Bulky Substituents 551
˚
TABLE 1 Selected Bond Lengths (A), Angles (deg), and Torsion Angles (deg) of 3
Se1 C1
S1 C33
1.938(3)
1.771(4)
Se1 C28
S1 C34
1.927(3)
1.776(3)
S2 C39
Se2 C45
1.772(3)
1.921(3)
S2 C40
Se2 C46
1.778(3)
1.933(3)
C28 Se1 C1
C40 S2 C39
C28 Se1 C1 C6
C34 S1 C33 C28
C40 S2 C39 C34
C46 Se2 C45 C40
99.15(13)
101.16(4)
−91.5(2)
115.3(3)
C33 S1 C34
C46 Se2 C45
C1 Se1 C28 C33
C33 S1 C34 C39
C39 S2 C40 C45
C45 Se2 C46–C47
100.87(17)
99.94(12)
−175.8(3)
156.4(2)
162.6(2)
−97.1(2)
−74.0(3)
−163.2(2)
3 are both nearly perpendicular to the benzene
ring of its connecting Tbt group (C28 Se1 C1 C6
= −91.5(2)◦ and C45 Se2 C46 C47 = −97.1(2)◦)
and almost parallel to the neighboring o-phenylene
moieties (C1 Se1 C28 C33 = −175.8(3)◦ and
C46 Se2 C45 C40 = −163.2(2)◦) as well as the case
of tetrathioether ligand 1. This conformation in 3
can be explained in terms of the steric hindrance
caused by the bulky Tbt groups.
are only few reports on the X-ray structural analy-
sis of neutral, 6-coordinate palladium(II) complexes
[6,16,17], although some cationic, 6-coordinate
complexes of palladium(II) have already been syn-
thesized using crown thioether ligands [1–5], S- and
N-donor macrocyclic ligands [18–20], and tris(2,4,6-
trimethoxyphenyl)phosphine ligands [21].
The selected bond lengths, angles, and torsion
angles of complex 6 are summarized in Table 2 to-
gether with those observed for complex 2. The bond
The 1H and 13C NMR spectra of 3 showed that the
two terminal TbtSe(o-phenylene) units were equiva-
lent to each other, suggesting flexible structure of 3
in solution. The 77Se NMR spectrum of 3 showed a
signal at 282 ppm, which is within a range of those
reported for diaryl selenides [15].
Synthesis and Structure of Palladium(II)
Complex 6 of Diselenodithioether Ligand 3
When 3 was allowed to react with Na2PdCl4 in
ethanol at room temperature for 1.5 h, the cor-
responding dichloropalladium complex 6 was ob-
tained as orange crystals in a good yield (Eq. (1)).
1
The structure of 6 was fully established by H, 13C,
and 77Se NMR spectrometry, MS, elemental analysis,
and single crystal X-ray diffraction.
The X-ray structural analysis of 6 showed a
structure similar to that of 2 [6], that is, the C2
symmetrical, distorted octahedral structure, where
the inner two sulfur atoms of ligand 3 and the two
chlorine atoms form a square planar arrangement
around the palladium(II) atom and the two terminal
selenium atoms of 3 weakly coordinate to the pal-
ladium center at the axial positions (Fig. 2). There
FIGURE 2 ORTEP drawing of 6 with thermal ellipsoids
(50% probability). Hydrogen atoms and a solvent molecule
(hexane) were omitted for clarity.
Heteroatom Chemistry DOI 10.1002/hc

552 Takeda, Isobe, and Tokitoh
˚
Atoms in Molecule Analysis
for the Pd · · · Se Interactions
TABLE 2 Selected Bond Lengths (A), Angles (deg), and
Torsion Angles (deg) of 6 and 2
6
2
To estimate the Pd · · · Se interactions (Pd1 · · · Se1
and Pd1 · · · Se1*) of the palladium(II) complex 6, we
examined the topological analysis using Bader’s the-
ory of atoms in molecules (AIM) [24–28]. In the AIM
analysis, chemical bondings can be identified by the
presence of a bond critical point (BCP), where the
electron density becomes a minimum along the bond
path.
For the Pd · · · Se interactions (Pd1 · · · Se1 and
Pd1 · · · Se1*) of 6, the BCPs could be located. The
electron density (ρ) at a BCP correlates with the
strength of an atomic interaction. The value of
Pd1 S1
Pd1 Cl1
2.2718(5)
2.3134(5)
3.14240(17)
89.74(2)
88.379(17)
94.51(3)
2.2615(9)
2.3117(9)
3.1755(8)
89.45(5)
88.15(3)
95.37(5)
71.19(3)
82.08(3)
89.37(3)
116.55(3)
178.6(3)
94.5(3)
Pd1 · · · Se1(S2)
S1 Pd1 S1*
S1 Pd1 Cl1
Cl1 Pd1 Cl1*
S1 Pd1 Se1(S2)
S1* Pd1 Se1(S2)
Cl1 Pd1 Se1(S2)
Cl1* Pd1 Se1(S2)
C4 C9 Se1(S2) C10
C9 Se1(S2) C10 C11
74.292(11)
80.485(12)
91.550(13)
112.990(12)
−178.09(14)
−96.98(14)
ρ obtained for the Pd · · · Se interactions (ρPd ··· Se
)
is 0.021 ea−0 3, which is smaller than those of
normal covalent bonds (e.g., ρC C = 0.24 ea−0 3)
but larger than those for the practical boundary
of molecules (ρ = 0.001 ea−0 3 [29]. In addition,
the ρPd ··· Se value is within the range of those for
neutral hydrogen bonds (ρ = 0.002–0.04 ea−0 3).
˚
distances of 6[Pd1–Cl1 (2.3134(5) A) and Pd1–S1
˚
(2.2718(5) A)] are close to those of tetrathioether
complex 2. The distances between the palladium
and the two terminal selenium atoms [Pd1 · · · Se1
2
The Laplacian (∇ ) of ρ denotes the curvature of
˚
= 3.14240(17) A] are shorter than the sum of the van
electron density in the 3D-topological space for
two interacting atoms and, in general, a negative
der Waals radii of palladium and selenium atoms
˚
(3.53 A) [22]. This suggests weak interaction between
2
value of ∇ ρ indicates that the electron density
the palladium atom (Pd1) and the terminal selenium
atoms (Se1 and Se1*) in the crystalline state. In ad-
dition, the Pd1 · · · Se1 distance is shorter than the
Pd1 · · · S2 distance of the sulfur analog 2, although
the van der Waals radii of selenium is larger than
that of sulfur. This indicates the stronger interac-
tion between Pd1 and Se1 in 6 than that between
Pd1 and S in 2. It is noteworthy that the torsion
angles around the terminal selenium atoms in palla-
dium complex 6 [C9 Se1 C10 C11 = −96.98(14)◦,
C4 C9 Se1 C10 = −178.09(14)◦] are close to those
of the free ligand 3. This result suggests that the
extremely bulky Tbt groups put the restrictions on
the conformation of ligand 3 in the structure of
complex 6 as well as in that of 3, that is, ligand 3
preferably has the conformation in which the C Se
(terminal) C planes are almost perpendicular to the
benzene rings of the Tbt groups and nearly parallel
to the neighboring o-phenylene rings.
is locally concentrated, while a positive value of
2
∇ ρ means that the electron density is locally
depleted. The positive value of ∇ ρPd ··· Se (0.054 ea−0 5)
2
suggests that the Pd1 · · · Se1 and Pd1 · · · Se1*
interactions are dominantly electrostatic in
nature.
CONCLUSION
A new diselenodithioether ligand 3 tethered with
two Tbt groups was synthesized and applied to the
complexation with Na2PdCl4, giving the correspond-
ing dichloropalladium complex 6. The X-ray struc-
tural analysis of 6 indicated its distorted octahedral
structure with the weak intramolecular interactions
between the two terminal selenium atoms and the
central palladium metal. The AIM calculations also
indicated the existence of the interaction between
the palladium and selenium atoms of 6 in the crys-
talline state, though very weak or no interaction was
suggested for 6 in solution as judged by the 77Se NMR
spectral data.
In the 77Se NMR spectrum of 6 measured
in 1,1,2,2-tetrachloroethane-d2 at 100◦C, a signal
appeared at slightly lower field (297 ppm) com-
pared with that of ligand 3 (290 ppm in 1,1,2,2-
tetrachloroethane-d2 at 100◦C). Since the 77Se NMR
chemical shifts of dichloropalladium complexes co-
ordinated with selenides have been reported to show
down-field shifts of 130–300 ppm compared with
those of the corresponding selenide ligands [23],
there may be no or very weak interaction between
the palladium and selenium atoms of 6 in solution.
EXPERIMENTAL
General Procedures
All reactions were carried out under an argon atmo-
sphere, unless otherwise noted. THF was purified
Heteroatom Chemistry DOI 10.1002/hc

Acyclic Diselenodithioether Ligand With Bulky Substituents 553
prior to use by using an Ultimate Solvent System
(Glass Contour Company) Laguna Beach, CA, USA
[30], and other solvents were used without purifica-
tion. Preparative gel permeation liquid chromatog-
raphy (GPLC) was performed on an LC-908 or LC-
918 instrument with JAI gel 1H+2H columns (Japan
Analytical Industry) using chloroform as an eluent.
Short column chromatography was performed with
Nacalai Tesque Silica Gel 60. The 1H NMR (300
MHz) and 13C NMR (75 MHz) spectra were measured
in CDCl3 with a JEOL AL-300 spectrometer using
CHCl3 (7.25 ppm) as internal standards for 1H NMR
Synthesis of Selenide 5
A mixture of Tbt-substituted diselenide 4 (8.62
g, 6.83 mmol), Cu2O (2.00 g, 14.0 mmol), and
1,2-diiodobenzene (5.0 mg, 15 mmol) in 2,4,6-
trimethylpyridine (60 mL) was refluxed for 6 h. The
reaction mixture was passed through a short col-
umn (SiO2, CHCl3) to remove inorganic salts. All
fractions were collected and washed with a 1.0 M
aqueous solution of HCl four times (100 mL × 4).
The organic layer was passed through a short col-
umn (SiO2, CHCl3) to remove water and inorganic
salts. After the eluate was evaporated, the reprecip-
itation from CH2Cl2/CH3CN gave selenide 5 (7.2 g,
8.6 mmol, 63%) as colorless crystals. 5: mp 180.8–
spectroscopy, and CDCl3 (77.0 ppm) as those for 13
C
NMR spectroscopy. The 77Se NMR (95 MHz) spec-
tra were measured in CDCl3 or C2D2Cl4 with a JEOL
JNM AL-300 spectrometer using diphenyl diselenide
(460 ppm) as an external standard. Mass spectral
data were obtained on a JEOL JMS-700 spectrome-
ter. All melting points were determined on a Yanaco
micro melting point apparatus and are uncorrected.
Elemental analyses were performed at the Micro-
analytical Laboratory of the Institute for Chemical
Research, Kyoto University.
1
182.0˚C. H NMR (300 MHz, CDCl3) δ-0.03 (36H,
s), 0.06 (18H, s), 1.36 (1H, s), 2.71 (2H, brs), 6.42
(1H, brs), 6.55 (1H, brs), 6.79 (1H, ddd, J = 7.8, 7.8,
1.5 Hz), 6.80 (1H, dd, J = 7.8, 1.5 Hz), 7.01 (1H,
ddd, J = 7.8, 7.8, 1.5 Hz), 7.71 (1H, dd, J = 7.8, 1.5
Hz); 13C NMR (75 MHz, CDCl3) δ 0.79 (q), 29.51 (d),
30.56 (d), 98.56 (s), 122.14 (d), 126.88 (d), 128.24 (d),
129.39 (s), 131.09 (d), 139.10 (d), 141.27 (s), 144.67
(s), 150.22 (s); 77Se NMR (57 MHz, CDCl3) δ 354
(s); HRMS (FAB) m/z calcd for C33H63ISeSi6 [M]+:
834.1755. Found: 834.1758.
Synthesis of Diselenide 4
To a THF solution (160 mL) of TbtBr (10.0 g,
15.8 mmol) was gradually added t-BuLi (2.2 M pen-
tane solution, 15.8 mL, 34.8 mmol) at −78◦C. Af-
ter stirring for 1 h at this temperature, Se (1.35 g,
17.1 mmol) was added to the yellow solution. The
reaction mixture was stirred at −78◦C for 1 h and
then at room temperature for 3 h. The resulting dark-
brown solution was added to a THF solution (40 mL)
of LiAlH4 (1.0 g, 26.4 mmol) at 0◦C. The reaction
mixture was stirred for 14 h at room temperature.
After removal of the solvents under reduced pres-
sure, ice water was added to the residue under air.
The mixture was extracted with hexane (250 mL).
After removal of the solvents under vacuum, the
residue was passed through a short column (SiO2,
hexane) to remove the remaining water. The evap-
oration of the eluate gave diselenide 4 (9.75 g, 7.72
mmol, 98%) as purple crystals. 4: mp 242.8–243.8˚C.
1H NMR (300 MHz, CDCl3) δ 0.04 (72H, s), 0.07 (36H,
s), 1.32 (2H, s), 2.77 (2H, brs), 2.85 (2H, brs), 6.36
(2H, brs), 6.49 (2H, brs); 13C NMR (75 MHz, CDCl3)
δ 0.76 (q), 0.81 (q), 1.07 (q), 30.45 (d), 31.36 (d),
31.48 (d), 121.73 (d), 126.67 (d), 128.72 (s), 143.87
(s), 149.73 (s), 149.96 (s); 77Se NMR (57 MHz, CDCl3)
δ 367; HRMS (FAB) m/z calcd for C54H118Se2Si12
[M]+: 1262.4795. Found: 1262.4810. Anal. Calcd for
C54H118Se2Si12: C, 51.37; H, 9.42%. Found: C, 51.49;
H, 9.42%.
Synthesis of Diselenodithioether 3
A mixture of Tbt-substituted selenide 5 (200 mg,
0.240 mmol), Cu2O (34 mg, 0.24 mmol), and
1,2-benzenedithiol (17 mg, 0.12 mmol) in 2,4,6-
trimethylpyridine (15 mL) was refluxed for 6 h.
The reaction mixture was subjected to short column
chromatography (SiO2, CHCl3) to remove inorganic
salts. The mixture was washed with a 1.0 M aque-
ous solution of HCl four times (100 mL × 4).
The organic layer was passed through a short col-
umn (SiO2, CHCl3) to remove water and inor-
ganic salts, and then the eluate was evaporated.
The residue was subjected to GPLC (CHCl3) to
give diselenodithioether 3 (131 mg, 0.084 mmol,
70%) as colorless crystals. 3: mp 107.8–108.5◦C.
1H NMR (300 MHz, CDCl3) δ–0.04 (72H, s), 0.07
(36H, s), 1.37 (2H, s), 2.76 (4H, brs), 6.43 (2H,
brs), 6.57 (2H, brs), 6.80 (2H, m), 6.95–7.14 (8H,
m), 7.24 (2H, m); 13C NMR (75 MHz, CDCl3) δ
0.49 (q), 0.84 (q), 29.23 (d × 2), 30.51 (d), 122.21
(d), 126.16 (d), 126.45 (s), 127.06 (d), 127.54 (d),
128.20 (d), 130.14 (d), 130.48 (d), 132.24 (s), 133.24
(d), 136.95 (s), 139.41 (s), 144.36 (s), 150.60 (s ×
2); 77Se NMR (57 MHz, CDCl3) δ 282 (s); 77Se NMR
(57 MHz, C2D2Cl4, 100◦C) δ 290 (s); HRMS (FAB) m/z
calcd for C72H130S2Se2Si12 [M]+: 1554.5176. Found:
Heteroatom Chemistry DOI 10.1002/hc

554 Takeda, Isobe, and Tokitoh
150.99 (s). 77Se NMR (57 MHz, C2D2Cl4, 100◦C) δ
297 (s); LRMS (FAB) m/z 1695 [M Cl]+. Anal. calcd
for C72H130Cl2PdS2Se2Si12: C, 49.92; H, 7.56%. found:
C, 49.88; H, 7.73%.
1554.5196. Anal. calcd for C72H130S2Se2Si12: C, 55.62;
H, 8.43%. Found: C; 55.71; H, 8.35%.
Synthesis of Dichloropalladium Complex 6
To an EtOH solution (40 mL) of diselenodithioether
3 (200 mg, 0.128 mmol) was added a solution of
Na2PdCl4 (46.0 mg, 0.156 mmol) in 10 mL of EtOH.
The mixture was stirred for 1.5 h at room temper-
ature, and the resulting orange suspension was fil-
trated. After the addition of CHCl3 to the precipi-
tates, the mixture was filtered. The orange filtrate
was evaporated to give dichloropalladium complex
6 (214 mg, 0.123 mmol, 96%) as orange crystals. 6:
mp 245.8–246.2◦C (dec.). 1H NMR (300 MHz, CDCl3,
50◦C) δ − 0.04 (72H, brs), 0.08 (36H, brs), 1.41 (2H,
brs), 2.59 (4H, brs), 6.52 (4H, brs), 6.76 (2H, br),
7.18 (4H, br), 7.42 (4H, br), 7.82 (2H, br); 13C NMR
(75 MHz, CDCl3) δ 0.73 (q), 1.27 (q), 1.27 (q), 30.71
(d), 30.71 (d × 2), 122.34 (d), 124.55 (s), 125.65 (d),
126.99 (s), 127.68 (s), 130.34 (d), 130.94 (d), 131.36
(d), 132.07 (d), 136.38 (d), 140.45 (s), 145.67 (s),
X-Ray Structural Analysis of 3 · 0.5CHCl3,
and 6 · C6 H
14
Single crystals of 3 · 0.5CHCl3 and 6 · C6H14 suit-
able for X-ray structural analysis were obtained
by slow recrystallization from CHCl3/CH3CN and
hexane/CH2Cl2/EtOH, respectively. The crystals were
mounted on a glass fiber. The intensity data were
collected on Rigaku/MSC Mercury CCD diffractome-
ter with graphite monochromated Mo Kα radia-
˚
tion (λ = 0.71069 A). The structures were solved by
direct methods (SHELXS-97) and refined by full-
matrix least-squares procedures on F2 for all reflec-
tions (SHELXL-97) [31]. All the non-hydrogen atoms
were refined anisotropically, and all hydrogens
were placed using AFIX instructions. The structural
data are shown in Table 3. CCDC No. 625473 for
TABLE 3 Crystal Data and Refinement Details for 3 · 0.5CHCl3, and 6 · C6H14
3 · 0.5CHCl3
6 · C6H14
Empirical formula
C72H130S2Se2Si12 · 0.5CHCl3
C72H130Cl2PdS2Se2Si12 · C6H14
Formula weight
Temperature
1614.56
103(2) K
Triclinic
P–1(#2)
12.0661(2)
16.7641(3)
1818.35
93(2) K
Monoclinic
C2/c(#15)
42.0219(3)
12.88340(10)
Crystal system
Space group
˚
a (A)
˚
b (A)
˚
c (A)
24.0984(9)
102.1972(13)
99.2470(15)
100.6024(7)
4581.03(15)
2
19.2052(2)
α (deg)
β (deg)
γ (deg)
90
105.7534(5)
90
10006.87(15)
4
3
˚
V (A )
Z
–3
Dcalc (mg m
)
1.171
1.089
0.30 × 0.05 × 0.05
2.48 to 25.00◦
31080
1.207
1.187
0.15 × 0.10 × 0.10
1.91 to 25.50◦
58165
–1
Absorption coefficient (mm
Crystal size (mm)
θ range
)
No. of reflections measured
No. of independent reflections
Rint
Completeness
15818
0.0261
98.0%
9277
0.0291
99.50%
Data/restraints/parameters
Goodness of fit on F2
Final R indices [I > 2σ(I )]a
15818/0/897
9277/35/483
1.015
1.069
R1 = 0.0411
wR2 = 0.1540
wR2 = 0.0977
R1 = 0.0587
wR2 = 0.1757
wR2 = 0.1073
R1 = 0.0242
wR2 = 0.0738
wR2 = 0.0628
R1 = 4 0.0270
wR2 = 0.0754
wR2 = 0.0654
R indices (all data)a
–3
˚
Largest diffraction peak and hole (e A
)
1.169 and −1.007
0.649 and −0.422
aR1 = ꢀ||F0| – |Fc||/ꢀ|F0|, wR2 = [(ꢀw(F02 – Fc2)2/ꢀw(F02)2]1/2
.
Heteroatom Chemistry DOI 10.1002/hc

Acyclic Diselenodithioether Ligand With Bulky Substituents 555
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is part of the Pacific Northwest Laboratory, P.O.
Box 999, Richland, WA 99352, USA, and funded
by the U.S. Department of Energy. The Pa-
cific Northwest Laboratory is a multiprogram
laboratory operated by Battelle Memorial Insti-
tute for the U.S. Department of Energy under
contract DE-AC06-76RLO 1830. Contact Karen
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ACKNOWLEDGMENTS
We are grateful to Assistant Professor Takahiro
Sasamori and Assistant Professor Noriyoshi
Nagahora, Institute for Chemical Research, Kyoto
University, for valuable discussions and some
part of spectroscopic measurements. We thank
Assistant Professor Makoto Yamashita, Faculty of
Engineering, University of Tokyo, for the valuable
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