Syntheses, crystal structures, and photophysical properties of platinum(II) complexes containing a disulfanenitrile ligand

Article abstract of DOI:10.1246/bcsj.20120336

New Pt^II complexes of bidendate Ph₂S(=N(Ph ₂)S≡N)₂ (ndsdsd) ligand were prepared, including the homoleptic complex, i.e., [Pt(ndsdsd)₂](hfac)₂ (1) (hfac: 1,1,1,5,5,5-hexafluoro-2,4-pentanedionato), and the heteroleptic complexes, [Pt(N^N)(ndsdsd)]X₂ [N^N = 1,10-phenanthroline (phen) (2), 4,7-diphenylphenanthroline (bathophen) (3); X = PF₆ (a) and ClO ₄ (b)] and [Pt(C^N)(ndsdsd)]X [C^N = 2-phenylpyridine (ppy) (4) and benzo[h]quinoline (bzq) (5); X = PF₆ (a) and ClO₄ (b)]. The complexes were characterized by IR, NMR spectroscopy, and elemental analysis. The molecular structures of complexes 1, 2a, and 4b have been elucidated by X-ray crystallographic analysis. The photophysical properties of all complexes were examined. Complexes 2 and 3a are very weakly luminescent in solution, whereas they show highly emissive in the solid state (Φ_em = 0.110.27).

Full text of DOI:10.1246/bcsj.20120336

608
Bull. Chem. Soc. Jpn. Vol. 86, No. 5, 608-614 (2013)
© 2013 The Chemical Society of Japan
Syntheses, Crystal Structures, and Photophysical Properties of
Platinum(II) Complexes Containing a Disulfanenitrile Ligand
Hiroya Honda,1,2 Takayoshi Fujii,*1 Junpei Kuwabara,2 and Takaki Kanbara2
1Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University,
Izumi, Narashino, Chiba 275-8575
2Tsukuba Research Center for Interdisciplinary Materials Science (TIMS), Graduate School of
Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573
Received December 10, 2012; E-mail: fujii.takayoshi@nihon-u.ac.jp
New PtII complexes of bidendate Ph2S(=N(Ph2)S¸N)2 (ndsdsd) ligand were prepared, including the homoleptic
complex, i.e., [Pt(ndsdsd)2](hfac)2 (1) (hfac: 1,1,1,5,5,5-hexafluoro-2,4-pentanedionato), and the heteroleptic complexes,
[Pt(N^N)(ndsdsd)]X2 [N^N = 1,10-phenanthroline (phen) (2), 4,7-diphenylphenanthroline (bathophen) (3); X = PF6 (a)
and ClO4 (b)] and [Pt(C^N)(ndsdsd)]X [C^N = 2-phenylpyridine (ppy) (4) and benzo[h]quinoline (bzq) (5); X = PF6 (a)
and ClO4 (b)]. The complexes were characterized by IR, NMR spectroscopy, and elemental analysis. The molecular
structures of complexes 1, 2a, and 4b have been elucidated by X-ray crystallographic analysis. The photophysical
properties of all complexes were examined. Complexes 2 and 3a are very weakly luminescent in solution, whereas they
show highly emissive in the solid state (Φem = 0.11-0.27).
Over the past few years, our group has been interested in the
pared homo- and heteroleptic PtII complexes bearing the ndsdsd
ligand.
coordination chemistry of sulfur-nitrogen ligands. A number of
their metal complexes have been reported to date, and many
have been characterized crystallographically.1-5 In the solid
state, they show a unique variety of structures with a range of
bonding modes.
In this paper, we describe the syntheses and crystal
structures of a variety of PtII complexes: [Pt(ndsdsd)2](hfac)2
(hfac: 1,1,1,5,5,5-hexafluoro-2,4-pentanedionato), [Pt(N^N)-
(ndsdsd)]X2, and [Pt(C^N)(ndsdsd)]X [N^N = 1,10-phenan-
throline (phen), 4,7-diphenylphenanthroline (bathophen);
C^N = 2-phenylpridine (ppy), benzo[h]quinoline (bzq), and
X = PF6, ClO4]. For comparison, we also prepared [Pt(phen)-
(tps)2](PF6)2 (tps: triphenyl--6-sulfanenitrile). In addition, the
photophysical properties of theses complexes were examined.
Recently, we prepared fluoro(diphenyl)--6-sulfanenitrile
(Ph2FS¸N) and further reported the formation of aryl-sub-
stituted -6-sulfanenitriles from the reaction of Ph2FS¸N with
several nucleophiles.6-9 These aryl-substituted -6-sulfane-
nitriles are typically stable under acidic or alkaline condi-
tions, with the exception of the alkoxy- and fluoro-substituted
compounds, which hydrolyze to the corresponding sulfox-
imides, and have nucleophilic character at the thiazyl nitrogen
(SVI¸N). For example, triphenyl--6-sulfanenitrile (Ph3SN)
reacts with several electrophiles and CuCl2 to give the corre-
sponding iminosulfonium salts ([Ph3SNR][X]: R = alkyl,
tosyl, acyl, NO2) and copper complexes ([CuCl2{¯-NSPh3}]2
and [CuCl2{Ph3SN}2]).3,10 In addition, we have synthesized
a new type of -6-sulfanenitrile with an SN triple bond at
both ends, N,N-bis[(nitrilo(diphenyl)--6-sulfanyl)](diphenyl)-
-6-sulfanediimide Ph2S(=N(Ph2)S¸N)2) (ndsdsd), and found
that the two terminal nitrogen atoms of this compound chelate
to CoII, NiII, CuII, and PdII centers.4,8 The X-ray structures
of these complexes reveal eight-membered rings containing
ndsdsd and the metal centers and adopt a boat-twist conforma-
tion. The bond order in the ndsdsd backbone is maintained
as N¸S-N=S=N-S¸N.4 Among these ligands, triphenyl--6-
sulfanenitrile (Ph3S¸N) and -6-sulfanenitrile with a nitrilo and
an imino group (type A) or two nitrilo groups (type B, ndsdsd)
at both ends have been examined in metal complexes and
have been shown to complexes as monodendate or biden-
tate ligands.3-5 As a further extension of these studies, we pre-
Results and Discussion
Synthesis of PtII Complexes. The synthetic routes to the
homo- and heteroleptic complexes are illustrated in Scheme 1.
The homoleptic PtII complex, [Pt(ndsdsd)2](hfac)2 (1), was pre-
pared by refluxing [Pt(hfac)2]11 with ndsdsd8 at a ratio of 1:2
in methanol for 6 h. The heteroleptic [Pt(N^N)(ndsdsd)]X2
[N^N = phen (2) and bathophen (3); X = PF6 (a) and ClO4
(b)] complexes were prepared by reacting [Pt(N^N)Cl2]12 with
ndsdsd at a stoichiometric ratio in DMSO at 90 °C for 3 h
followed by treatment with KPF6 or NaClO4. Similar treatment
of [PtCl2(phen)] with tps at a ratio of 1:2, followed by addition
of KPF6, gave [Pt(phen)(tps)2](PF6)2. To prepare [Pt(C^N)-
(ndsdsd)]X [C^N = ppy (4) and bzq (5); X = PF6 (a) and ClO4
14
(b)], the reaction of [PtCl(ppy)(Hppy)]13 or [Pt(bzq)(¯-Cl)]2
with ndsdsd and KPF6 or NaClO4 was carried out in methanol
at ambient temperature for 5 h.
All complexes were fully characterized by IR, 1H and
13C NMR spectroscopies, and elemental analysis. In the IR
spectra of 1-5, the IR band was observed between 1301-
1309 cm¹1, which is attributed to the terminal S-N stretching
vibrations. The S-N stretching band (1313 cm¹1) of ndsdsd
Published on the web March 23, 2013; doi:10.1246/bcsj.20120336

H. Honda et al.
Bull. Chem. Soc. Jpn. Vol. 86, No. 5 (2013)
609
μ
Scheme 1. The synthetic routes to homo- and heteroleptic complexes 1-5 and [Pt(phen)(tps)2](PF6)2.
shifted to a slightly lower frequency upon complexation; a
similar shift was previously observed in [Pd(N^N)(ndsdsd)]Cl2
[N^N = ndsdsd (1307 cm¹1), bpy (1306 cm¹1), phen (1304
cm¹1), and bathophen (1304 cm¹1)].4b The resonances observed
by NMR have been assigned on the basis of comparison with
spectra of the ligands and the integration values and coupling
constants. The 1H NMR spectra of 2 and 4 do not vary
N(2)
S(2)
S(1)
N(3)
N(1)
N(4)*
Pt(1)
S(3)
N(4)
N(1)*
1
significantly with different anions. In the H NMR spectra of
the ppy and bzq derivatives, 4 and 5a, platinum satellites are
observed at low-field (4a, ¤ 9.08, JPt-H = 39.8 Hz; 4b, ¤ 9.08,
J
Pt-H = 38.8 Hz; and 5a, ¤ 9.27, JPt-H = 37.6 Hz). The JPt-H
values for 4 and 5a are smaller than those of [Pt(ppy)-
(NCMe)2]ClO4 and [Pt(bzq)(NCMe)2]ClO4 in CD3CN (46.1
and 47.3 Hz),15 which is indicative of the stronger trans influ-
ence of the nitrogen atom in the ndsdsd ligand with respect to
the acetonitrile ligand.
Figure 1. ORTEP drawing of 1 [50% probability thermal
ellipsoids; H, C atoms (apart from the C¡ atoms of the
phenyl rings), hexafluoroacetylacetonato anions, and aceto-
nitrile molecules have been omitted for clarity].
Crystal Structures of PtII Complexes. For complexes 1,
2a, 4b, and [Pt(phen)(tps)2](PF6)2, the slow diffusion of con-
centrated acetonitrile solutions into diethyl ether resulted in
the formation of single crystals from which their solid-sate
structures were established by X-ray crystallography. ORTEP
drawings of 1, 2a, and 4b are depicted in Figures 1-3, while
that of [Pt(phen)(tps)2](PF6)2 is shown in Figure S1. Selected
bond lengths and angles for 1, 2a, and 4b are tabulated
in Tables 1-3. The Pt atom in homoleptic complex 1 is sur-
rounded by four nitrogen atoms from two coordinated ndsdsd
ligands. The Pt atoms in heteroleptic complexes 2a and 4b are
surrounded by two coordinated N atoms of the ndsdsd and
diimine ligands, and the C and N atoms of the cyclometalated
groups, respectively. The geometry around the Pt center in 1
adopts an essentially flat structure with the four coordinating N
atoms of the ndsdsd ligands. Heteroleptic complexes 2a and 4b
exhibit nearly planar geometries (2a, dihedral angles between
the N-Pt-N planes is 3.6°; 4b, dihedral angles between the
N-Pt-N plane and C-Pt-N plane is 2.9°). The eight-membered

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Bull. Chem. Soc. Jpn. Vol. 86, No. 5 (2013)
Pt Complexes with a Disulfanenitrile Ligand
Pt(NSN)2S rings in 1, 2a, and 4b adopt a boat-twist confor-
mation, and the coordinated and internal S-N bond lengths
of the ndsdsd ligands are very similar. The coordinated S-N
bond lengths (1.474(5)-1.502(3) ¡) in 1, 2a, and 4b are shorter
than the internal S-N double bond length of the free ligand
(1.550(2) ¡)8 and close to the coordinated S-N bond lengths
of [Pd(N^N)(ndsdsd)]Cl2 (N^N = ndsdsd, bpy, and phen;
1.476(2)-1.495(5) ¡)4b and [M(ndsdsd)2]Cl2 bearing square-
planar Ni(II) and Cu(II) centers (M = Ni and Cu; 1.468(3)-
1.4792(14) ¡).4a The internal S-N bond lengths of 1, 2a, and
4b range from 1.549(5) to 1.671(5) ¡. Such bond lengths lie
between those of single and double bonds and are close to
those of the free state (1.550(2)-1.656(2)).8 These results indi-
cate that the bond order in the N¸S-N=S=N-S¸N backbone
of ndsdsd has been maintained after complexation.4 The Pt£Pt
distance in 1, 2a, and 4b between adjacent complexes is 10.38,
6.49, and 8.48 ¡, respectively, indicating there is no d8-d8
interaction, while the neighboring molecules in 2a are arranged
as head-to-tail dimers through intermolecular ³£³ interactions
(3.30 ¡) between the phen ligands.
N(3)
S(3)
S(2)
N(4)
N(5)
N(2)
Pt(1)
N(6)
N(1)
S(1)
Figure 2. ORTEP drawing of 2a [50% probability thermal
ellipsoids; H, C atoms (apart from the C¡ atoms of the
phenyl rings), hexafluorophosphate anions, acetonitrile,
and diethyl ether molecules have been omitted for clarity].
N(3)
N(1)
N(5)
Pt(1)
S(3)
S(2)
S(1)
C(37)
N(2)
N(4)
Photophysical Properties of PtII Complexes. Absorption
Spectroscopy: Representative absorption and fluorescence
data for complexes 1-5 and [Pt(phen)(tps)2](PF6)2 are summa-
rized in Tables 4 and S2. Room-temperature electronic spectra
of complexes 1, [Pt(phen)(tps)2](PF6)2, and 2a-5a in aceto-
nitrile are shown in Figures S2, S3, and 4, respectively. By
comparing the spectra with those in the literature16,17 and of
the free ligand, the intense absorption bands at - < 350 nm
are attributed to ligand-centered (LC) transitions located on
the N^N and C^N ligands. The broad low-energy absorptions
(with a shoulder) tailing to 380-450 nm are mainly ascribed to
charge-transfer (CT) transitions composed of both metal-to-
ligand charge-transfer (MLCT) and ligand-to-ligand charge-
transfer (LLCT) transitions.
Figure 3. ORTEP drawing of 4b [50% probability thermal
ellipsoids; H, C atoms (apart from the C¡ atoms of the
phenyl rings), perchlorate anions and acetonitrile mole-
cules have been omitted for clarity].
Table 1. Selected Bond Lengths (¡) and Angles (o) for
Complex 1
Pt(1)-N(1)
Pt(1)-N(4)
S(1)-N(1)
S(1)-N(2)
2.0322(13) S(2)-N(2)
2.0189(16) S(2)-N(3)
1.4860(15) S(3)-N(3)
1.6516(16) S(3)-N(4)
1.5584(17)
1.5502(16)
1.6654(14)
1.4820(14)
N(1)-Pt(1)-N(4) 90.78(6)
N(1)-Pt(1)-N(4)* 89.22(6)
Emission Spectroscopy: Heteroleptic PtII complexes 2a-
5a are photoluminescent at low (77 K) and room temperature.
These complexes show a rigidochromic blue shift upon cooling
of the solution sample to 77 K, while homoleptic PtII com-
plex 1 is only emissive at 77 K. The results are summarized
in Table 4, and representative emission spectra are shown
in Figures 5-7. As can be observed in Figure 5, [Pt(ppy)-
(ndsdsd)]PF6 (4a) displays a typical structured band (501
and 530 nm) with vibrational progressional spacing character-
istic (1.09 © 103 cm¹1) of ppy ligands in acetonitrile solution
at ambient temperature. The solution emission spectrum of
[Pt(bzq)(ndsdsd)]PF6 (5a) exhibits an unstructured band (524
nm) at room temperature, while in the glassy state (77 K)
a structured emission band (490, 527, and 579 nm) with a
Table 2. Selected Bond Lengths (¡) and Angles (o) for
Complex 2a
Pt(1)-N(1)
Pt(1)-N(4)
Pt(1)-N(5)
Pt(1)-N(6)
S(1)-N(1)
1.995(3)
2.033(2)
2.013(3)
2.013(3)
1.502(3)
S(1)-N(2)
S(2)-N(2)
S(2)-N(3)
S(3)-N(3)
S(3)-N(4)
1.665(3)
1.564(3)
1.571(3)
1.665(3)
1.494(3)
N(1)-Pt(1)-N(4) 92.28(12)
N(1)-Pt(1)-N(5) 173.00(11) N(4)-Pt(1)-N(6) 175.11(12)
N1-Pt(1)-N(6) 92.30(12) N(5)-Pt(1)-N(6) 81.41(12)
N(4)-Pt(1)-N(5) 94.11(12)
¹1
vibronic band of 1.44 © 103 and 1.70 © 103 cm is observed.
Table 3. Selected Bond Lengths (¡) and Angles (o) for
Complex 4b
These emission bands are assigned as LC/MLCT and a similar
trend is observed in [Pt(C^N)L]n+ 17,18
.
At ambient temperature in acetonitrile (1 © 10¹4 M), an
orange emission band at -max = 589 nm from [Pt(phen)-
(ndsdsd)](PF6)2 (2a) is observed, as shown in Figure 6, while
[Pt(phen)(tps)2](PF6)2 is not emissive. Also, complex 3a shows
an unstructured emission band (-max = 552 nm, Figure S4).
Emissions of heteroleptic PtII complexes 2-5 bearing the ndsdsd
ligand as well as PtII diimine and PtII phenylpyridine complexes
with a bidentate ligand (N^N and P^P) have been observed
Pt(1)-N(1)
Pt(1)-N(4)
Pt(1)-N(5)
Pt(1)-C(37)
S(1)-N(1)
2.092(4)
2.051(4)
1.998(5)
1.987(5)
1.474(5)
S(1)-N(2)
S(2)-N(2)
S(2)-N(3)
S(3)-N(3)
S(3)-N(4)
1.671(5)
1.568(4)
1.549(5)
1.666(4)
1.483(4)
N(1)-Pt(1)-N(4) 92.47(19) N(4)-Pt(1)-C(37) 94.8(2)
N(1)-Pt(1)-N(5) 92.1(2)
N1-Pt(1)-C(37) 172.1(2)
N(4)-Pt(1)-N(5)
N(5)-Pt(1)-C(37) 80.6(2)
175.47(19)

H. Honda et al.
Bull. Chem. Soc. Jpn. Vol. 86, No. 5 (2013)
611
Table 4. Absorption and Emission Data for Complexes 1-5
¹1
Complex
-
abs/nm (103¾/M¹1 cm
)
Medium (T/K)
-em/nm (-ex/nm)
Quantum yield
1
225 (69.9), 304 (29), 368 (2.8)
MeCN (298) 10¹4 M
®
®
®
®
®
CH2Cl2/MeOH(1/1) (77) 10¹4 M 577 (375)
solid (298)
solid (77)
®
576 (400-460)
2a
3a
4a
5a
226 (70.7), 257 (39.1), 273 (32.2),
329 (7.9), 387 (5.0)
MeCN (298) 10¹4 M
589 (360-420)
0.001>
®
CH2Cl2/MeOH(1/1) (77) 10¹4 M 474, 508, 545 (295-390)
solid (298)
solid (77)
556 (435-475)
520, 549 (400-470)
0.14
®
224 (82.3), 267 (40.8), 296 (42.6),
339 (6.8), 402 (3.5)
MeCN (298) 10¹4 M
CH2Cl2/MeOH(1/1) (77) 10¹4 M 513, 549, 592 (310-405)
solid (298)
solid (77)
552 (330-415)
0.001>
®
565 (440-500)
530, 565 (425-460)
0.27
®
288 (19.4), 374 (5.4)
MeCN (298) 10¹4 M
CH2Cl2/MeOH(1/1) (77) 10¹4 M 486, 520 (290-415)
solid (298)
solid (77)
501, 530 (325-415)
0.001>
®
532 (400-450)
503, 540 (420-455)
0.012
®
218 (83.5), 259 (37.4), 348 (8.4), 384 (5.7) MeCN (298) 10¹4 M
524 (388)
0.001>
®
CH2Cl2/MeOH(1/1) (77) 10¹4 M 490, 527, 579 (325-380)
solid (298)
solid (77)
535 (400-475)
516, 553 (450-470)
0.007
®
200
1.0
0.8
0.6
0.4
0.2
0
r.t.
2a
3a
4a
5a
77 K
150
100
50
0
200
250
300
350
400
450
500
450
500
550
600
650
700
Wavelength/nm
Wavelength/nm
Figure 6. Emission spectra of 2a in MeCN (r.t., 10¹4 M)
and CH2Cl2/MeOH (1/1) (77 K, 10¹4 M).
Figure 4. UV-vis absorptiom spectra of 2a-5a (MeCN,
10¹5 M).
1.0
1.0
4a (r.t.)
r.t.
0.8
0.8
4a (77 K)
77 K
5a (r.t.)
5a (77 K)
0.6
0.4
0.6
0.4
0.2
0
0.2
0
450
500
550
600
650
700
490
540
590
640
690
Wavelength/nm
Wavelength/nm
Figure 5. Emission spectra of 4a and 5a in MeCN (r.t.,
10¹4 M) and CH2Cl2/MeOH (1/1) (77 K, 10¹4 M).
Figure 7. Emission spectra of 2a in the solid state.
in solution states at room temperature.19 Upon cooling the solu-
tions (1 © 10¹4 M) to a glassy state (77 K), the emission bands
of 2a (589 nm) and 3a (552 nm) become clearly structured with
their maxima shifted to higher energies (i.e., a rigidochromic
blue shift) (2a: 474, 508, 545 (sh) nm; 3a: 513, 549, 592 (sh)
nm), as shown in Figures 6 and S4. The solid-state lumines-
cence of 2a and 3a at ambient temperature and 77 K also show a
rigidochromic blue shift (Figures 7 and S5). This trend indi-
cates that metal-metal-to-ligand charge transfer (MMLCT) and
ligand-ligand ³ excimeric emission does not occur. Interest-

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Bull. Chem. Soc. Jpn. Vol. 86, No. 5 (2013)
Pt Complexes with a Disulfanenitrile Ligand
ingly, the quantum yields of 2a (Φem = 0.14), 2b (Φem = 0.11),
and 3a (Φem = 0.27) in the solid state at ambient temperature are
much larger than those obtained in acetonitrile solution (2a, 2b,
and 3a, Φem < 0.001). Furthermore, the differences are signifi-
cant compared to those of cyclometalated complexes 4a and
5a (Table 4). Luminescence is often weakened or quenched
in condensed solid systems, a phenomenon widely known as
concentration quenching. However, some nonemissive com-
pounds in their dilute solutions have been found to exhibit
strong emission in the solid states.20 The strong emission in the
solid states is due to intermolecular hydrogen-bonding inter-
actions (for example; C-H£³ and C-H£O hydrogen-bonding
interactions) in these compounds that help rigidify the molec-
ular conformation and suppress the molecular mobility. In
accordance with the crystal packing of 2a (Figure S6), hydro-
gen bonds between the hydrogen atoms attached to the phenyl
groups of ndsdsd and nitrogen, and the fluorine atoms of the
spectrometer. Absorption spectra were recorded on a JASCO
V-550 spectrometer. The emission spectra were measured with
a JASCO FP-6500 spectrophotometer. Luminescence quan-
tum yields in solution and solid state were obtained by
a Hamamatsu photonics C9920-02 and a JASCO ILF-533,
respectively. X-ray diffraction analysis was carried out using
a Bruker APEX-II CCD. Elemental analyses were carried out
with a Perkin-Elmer 2400 CHN Elemental Analyzer.
Synthesis and Characterization. All reagents and sol-
vents were obtained commercially and were further purified
by general methods when necessary. The ligands, Ph2S(=N-
(Ph2)S¸N)2 (ndsdsd)8 and Ph3SN (tps)7a were synthesized as
described previously. The starting materials [Pt(hfac)2],11 [Pt-
(N^N)Cl2] (N^N = phen, bathophen),12 [PtCl(ppy)(Hppy)],13
14
[Pt(bzq)(¯-Cl)]2 were prepared according to the method
reported in the literature.
[Pt(ndsdsd)2](hfac)2 (1): [Pt(hfac)2] (30.4 mg, 0.05 mmol)
and ndsdsd¢2H2O (65 mg, 0.1 mmol) were added to methanol
(2 mL). The mixture was refluxed for 6 h. After the reaction
mixture was cooled to ambient temperature. The solvent was
evaporated under reduced pressure. The residue was washed
with CHCl3, and recrystallized from MeCN/Et2O to give the
corresponding pale yellow crystals.
anions are observed (Nndsdsd£Hndsdsd, 2.65 ¡; P-F£Hndsdsd
,
2.39-2.66 ¡). C-H£³ hydrogen bonds (2.54 ¡) are evident
between the hydrogen atoms of one phen ligand and the ³
electrons of the phenyl rings of an adjacent ndsdsd ligand.
Hence, the larger quantum yields of complex 2a in the solid
state can be attributed to the suppression of nonradiative decay
through the intermolecular hydrogen-bonding interactions.
In addition, the strong emissions of complexes 2 and 3 in the
solid states are an interesting phenomenon because of difference
from general emission behavior21 and relatively less investiga-
tion for luminescent properties of mononuclear PtII chelate
complexes containing diimine ligand in the solid states.19,22
1: Yield: 71 mg, 78%; mp 215-217 °C (decomp. mono-
1
hydrate). H NMR (400 MHz, CD3OD): ¤ 7.33 (t, J = 7.9 Hz,
16H), 7.42 (t, J = 7.9 Hz, 8H), 7.50 (t, J = 7.9 Hz, 8H), 7.63
(t, J = 7.9 Hz, 4H), 7.69 (d, J = 7.9 Hz, 16H), 7.81 (d, J =
16.3 Hz, 8H); 13C NMR (100 Hz, CD3OD): ¤ 85.9, 118.1,
121.0, 128.7, 130.3, 131.3, 134.3, 136.3, 136.9, 144.2, 175.4
(JF-C = 30.5 Hz); IR (KBr, cm¹1): 3061, 1670, 1553, 1526,
1473, 1446, 1307, 1246, 1191, 1132, 1076, 1029, 982; Anal.
Calcd for C82H64F12N8O5PtS6: C, 53.04; H, 3.47; N, 6.03%.
Found: C, 53.14; H, 3.63; N, 5.80%.
[Pt(ndsdsd)(N^N)]X2 [(N^N = phen (2) and bathophen
(3); X = PF6 (a) and ClO4 (b)]: [PtCl2(N^N)] (N^N = phen,
bathophen) (0.1 mmol) and ndsdsd¢2H2O (65 mg, 0.1 mmol)
were added to dimethyl sulfoxide (DMSO) (1 mL). The reac-
tion mixture was stirred at 90 °C for 3 h. After cooling to
ambient temperature, the solution was slowly added to a solu-
tion of KPF6 or NaClO4 (0.4 mmol) in methanol (5 mL). After
stirring for 3 h the precipitate was filtered and washed with
water and methanol. Recrystallization from MeCN/Et2O gave
the yellow solid 2a, 2b, and 3a, respectively.
Conclusion
The reaction of ndsdsd with appropriate precursors gives
the homoleptic complex, i.e., [Pt(ndsdsd)2](hfac)2 (1), and the
heteroleptic [Pt(N^N)(ndsdsd)]X2 [N^N = phen (2), bathophen
(3); X = PF6 (a) and ClO4 (b)] and [Pt(C^N)(ndsdsd)]X
([C^N = ppy (4) and bzq (5); X = PF6 (a) and ClO4 (b)] com-
plexes. Compared with [Pt(ppy)(NCMe)2]ClO4 and [Pt(bzq)-
1
(NCMe)2]ClO4, the JPt-H values of 4 and 5a in the H NMR
spectra reveal the stronger trans influence of the nitrogen atom
in the ndsdsd ligand than in the acetonitrile ligand. X-ray
crystallographic analyses of 1, 2a, and 4b show that the two
terminal nitrogen atoms in the ndsdsd ligand chelate to the Pt
center. The eight-membered Pt(NSN)2S rings in these com-
plexes adopt a boat-twist conformation. The coordinated and
internal S-N bond lengths are similar to those of the free
ligand. These results indicate that the bond order in the N¸
S-N=S=N-S¸N backbone of ndsdsd has been maintained
upon complexation. All complexes are emissive in the glassy
state at 77 K. Complex 2a exhibits emission in solution at room
temperature, while [Pt(phen)(tps)2](PF6)2 is not emissive. In
addition, complexes 2 and 3a show a strong emission in the
solid state (Φem = 0.11-0.27). Crystal packing of 2a indicates
that intermolecular hydrogen-bonding interactions contribute to
the strong emission in the solid state.
2a: Yield: 115.2 mg, 90%; mp 281-283 °C (decomp. mono-
1
hydrate). H NMR (400 MHz, CD3CN): ¤ 7.40-7.48 (m, 12H),
7.59 (t, J = 7.4 Hz, 4H), 7.65 (t, J = 7.4 Hz, 2H), 7.79 (dd,
J = 8.4, 0.8 Hz, 4H), 7.89-7.91 (m, 2H), 7.98 (d, J = 7.4 Hz,
8H), 8.12 (s, 2H), 8.78 (dd, J = 8.4, 1.2 Hz, 2H), 9.06 (dd,
J = 5.2, 1.2 Hz, 2H); 13C NMR (100 Hz, CD3CN): ¤ 126.7,
128.3, 128.6, 129.0, 130.6, 131.2, 131.6, 134.7, 134.8, 136.8,
140.1, 142.8, 148.5, 150.0; IR (KBr, cm¹1): 3070, 1582, 1472,
1447, 1308, 1211, 1176, 1071, 1015, 984, 840; Anal. Calcd for
C48H40F12N6OP2PtS3: C, 44.41; H, 3.11; N, 6.47%. Found: C,
44.13; H, 2.90; N, 6.62%.
2b: Yield: 97.5 mg, 82%; mp 283-285 °C (decomp. mono-
hydrate). H NMR (400 MHz, CD3CN): ¤ 7.40-7.48 (m, 12H),
Experimental
1
General Procedures.
with a BRUKER AVANCE-400S with TMS as an internal
standard. IR spectra were recorded on a JASCO FT/IR-4200
All NMR spectra were obtained
7.58 (t, J = 8.0 Hz, 4H), 7.66 (t, J = 8.0 Hz, 2H), 7.91 (d, J =
8.0 Hz, 2H), 7.98 (d, J = 8.0 Hz, 8H), 8.12 (s, 2H), 8.79 (dd,
J = 8.4, 1.2 Hz, 2H), 9.06 (dd, J = 5.2, 1.2 Hz, 2H); 13C NMR

H. Honda et al.
Bull. Chem. Soc. Jpn. Vol. 86, No. 5 (2013)
613
(100 Hz, CD3CN): ¤ 126.7, 128.3, 128.6, 129.0, 130.6, 131.2,
131.6, 134.7, 134.7, 136.6, 140.2, 142.8, 148.6, 150.0; IR
(KBr, cm¹1): 3088, 1617, 1470, 1445, 1306, 1214, 1194, 1089,
1016, 982; Anal. Calcd for C48H40Cl2N6O9PtS3: C, 47.76; H,
3.34; N, 6.96%. Found: C, 47.94; H, 3.38; N, 6.94%.
3a: Yield: 109.4 mg, 76%; mp 269-271 °C (decomp.).
1H NMR (400 MHz, CD3CN): ¤ 7.41-7.48 (m, 12H), 7.58-
7.69 (m, 16H), 7.80-7.84 (m, 6H), 8.00-8.05 (m, 10H), 9.13 (d,
J = 6.0 Hz, 2H); 13C NMR (100 Hz, CD3CN): ¤ 126.8, 128.3,
129.0, 129.7, 130.2, 130.5, 130.7, 130.9, 131.3, 134.7, 134.8,
136.4, 136.8, 142.9, 149.0, 149.6, 152.5; IR (KBr, cm¹1):
3060, 1595, 1473, 1446, 1309, 1294, 1213, 1073, 1031, 985,
843; Anal. Calcd for C60H46F12N6P2PtS3: C, 50.32; H, 3.24; N,
5.87%. Found: C, 50.19; H, 3.33; N, 5.76%.
[Pt(ndsdsd)(C^N)]X [C^N = ppy (4) and bzq (5); X =
PF6 (a) and ClO4 (b)]: [PtCl(ppy)(Hppy)] (0.1 mmol) or
[Pt(bzq)(¯-Cl)]2 (0.05 mmol) and ndsdsd¢2H2O (65 mg, 0.1
mmol) were added to methanol (2 mL) containing KPF6 or
NaClO4 (0.2 mmol) at ambient temperature. After stirring for
5 h the precipitate was filtered and washed with water and
methanol. Recrystallization from MeCN/Et2O gave the yellow
solid 4a, 4b and green solid 5a, respectively.
reaction mixture was stirred at 90 °C for 3 h. After cooling
to ambient temperature, the solution was slowly added to a
solution of KPF6 (0.4 mmol) in methanol (5 mL). After stirring
for 3 h, the solvent was evaporated under reduced pressure. The
residue was dissolved in acetonitrile and then filtered through
celite. The addition of diethyl ether to the filtrate gave the
corresponding yellow solid [Pt(phen)(tps)2](PF6)2.
[Pt(phen)(tps)2](PF6)2: Yield: 56.0 mg, 46%; mp 209-
1
211 °C (decomp. monohydrate). H NMR (400 MHz, CD3CN):
¤ 7.42 (d, J = 8.4 Hz, 2H), 7.52 (t, J = 16.2 Hz, 12H), 7.72
(t, J = 16.2 Hz, 6H), 7.95 (d, J = 9.6 Hz, 12H), 8.07 (s, 2H),
8.40 (dd, J = 5.2, 1.2 Hz, 2H), 8.62 (dd, J = 8.4, 1.2 Hz, 2H);
13C NMR (100 Hz, CD3CN): ¤ 125.9, 128.3, 129.6, 130.6,
131.3, 135.3, 139.2, 139.6, 148.6, 149.7; IR (KBr, cm¹1):
3063, 1475, 1446, 1265, 1152, 1065, 998, 840; Anal. Calcd for
C48H40F12N4OP2PtS2: C, 46.57; H, 3.26; N, 4.53%. Found: C,
46.58; H, 3.08; N, 4.85%.
Crystal Structure Determination. X-ray quality crystals
were obtained by the slow diffusion of diethyl ether into aceto-
nitrile (1, 2a, 4b, and [Pt(phen)(tps)2](PF6)2). Intensity data
were collected on a Bruker APEX-II CCD diffractometer
with Mo K¡ radiation. A full matrix least-squares refinement
was used for non-hydrogen atoms with anisotropic thermal
parameters method by SHELXL-97 program.23 Hydrogen
atoms were placed at the calculated positions and were
included in the structure calculation without further refinement
of the parameters. Crystallographic data have been deposited
with Cambridge Crystallographic Data Centre: Deposition
number CCDC-923873 (1), 923874 (2a), 923875 (4b), and
923876 ([Pt(phen)(tps)2](PF6)2). Copies of the data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html (or from the Cambridge Crystallographic Data
Centre, 12, Union Road, Cambridge, CB2 1EZ, U.K.; Fax:
+44 1223 336033; e-mail: deposit@ccdc.cam.ac.uk).
4a: Yield: 87.3 mg, 79%; mp 179-181 °C (decomp.).
1H NMR (400 MHz, CD3CN): ¤ 6.91-6.99 (m, 2H), 7.10-
7.13 (m, 1H), 7.34-7.44 (m, 14H), 7.48-7.54 (m, 4H), 7.59 (t,
J = 8.5 Hz, 2H), 7.68 (d, J = 8.0 Hz, 1H), 7.74 (dd, J = 6.8,
0.8 Hz, 4H), 7.86-7.94 (m, 9H), 9.08 (dd, J = 6.0, 0.8 Hz,
J
Pt-H = 39.8 Hz, 1H); 13C NMR (100 Hz, CD3CN): ¤ 119.5,
123.2, 123.4, 124.0, 127.9, 128.4, 128.8, 130.1, 130.2, 130.8,
131.3, 133.6, 133.8, 134.3, 135.9, 136.2, 139.0, 144.4, 145.0,
145.7, 146.4, 149.9, 168.2; IR (KBr, cm¹1): 3060, 1607, 1473,
1445, 1305, 1245, 1075, 1031, 984, 832; Anal. Calcd for
C47H38F6N5PPtS3: C, 50.90; H, 3.45; N, 6.31%. Found: C,
50.68; H, 3.65; N, 6.57%.
4b: Yield: 87.2 mg, 82%; mp 142-144 °C (decomp. di-
1
hydrate). H NMR (400 MHz, CD3CN): ¤ 6.91-7.00 (m, 2H),
This work was supported by a Grants-in-Aid for Scientific
Research (Nos. 19550051 and 22550045) from the Ministry of
Education, Culture, Sports, Science and Technology of Japan
and a special grant from the College of Industrial Technology,
Nihon University.
7.10-7.13 (m, 1H), 7.34-7.45 (m, 14H), 7.48-7.54 (m, 4H),
7.59 (t, J = 8.4 Hz, 2H), 7.68 (d, J = 8.4 Hz, 1H), 7.74 (dd,
J = 8.8, 1.2 Hz, 4H), 7.85-7.94 (m, 9H), 9.08 (dd, J = 5.6,
0.8 Hz, JPt-H = 38.8 Hz, 1H); 13C NMR (100 Hz, CD3Cl): ¤
118.3, 121.4, 122.6, 123.1, 126.8, 127.1, 127.6, 127.7, 127.9,
129.2, 129.5, 129.8, 130.5, 131.0, 132.7, 134.9, 135.1, 135.6,
137.4, 143.5, 143.9, 144.8, 148.8; IR (KBr, cm¹1): 3058, 1606,
1480, 1445, 1305, 1240, 1091, 1030, 982; Anal. Calcd for
C47H42ClN5O6PtS3: C, 51.34; H, 3.85; N, 6.37%. Found: C,
50.92; H, 3.74; N, 6.01%.
5a: Yield: 68.8 mg, 61%; mp 141-143 °C (decomp.).
1H NMR (400 MHz, CD3CN): ¤ 7.31-7.45 (m, 12H), 7.47-
7.54 (m, 6H), 7.58-7.65 (m, 4H), 7.74-7.78 (m, 6H), 7.95-8.00
(m, 8H), 8.41 (dd, J = 8.0, 1.4 Hz, 1H), 9.27 (dd, J = 5.6,
1.4 Hz, JPt-H = 39.2 Hz, 1H); 13C NMR (100 Hz, CD3CN): ¤
121.1, 122.4, 124.2, 127.4, 127.9, 128.3, 128.4, 128.8, 129.8,
130.1, 130.2, 130.4, 130.9, 131.3, 131.9, 133.6, 133.9, 134.1,
134.3, 136.0, 136.1, 137.7, 144.3, 146.5, 148.9; IR (KBr,
cm¹1): 3060, 1568, 1473, 1445, 1301, 1242, 1073, 1031, 983,
846; Anal. Calcd for C49H38F6N5PPtS3: C, 51.94; H, 3.38; N,
6.18%. Found: C, 51.64; H, 3.31; N, 5.89%.
Supporting Information
Listings of crystallographic data, molecular structure of
[Pt(phen)(tps)2](PF6)2, absorption and emission date for 2b
and [Pt(phen)(tps)2](PF6)2, UV-vis absorption spectra of 1 and
[Pt(phen)(tps)2](PF6)2, emission spectra of 3a, and molecular
packing of 2a. This material is available free of charge on the
Web at: http://www.csj.jp/journals/bcsj/.
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