Synthesis and characterization of electron donor-acceptor platinum(II) complexes composed of N, N -diphenylpyridineamine and triphenylamine ligands

Article abstract of DOI:10.1021/ic500290m

The synthesis and electronic properties of a series of platinum(II) complexes composed of electron-donor and electron-acceptor components as potential photovoltaic materials is reported. The complexes are composed of triphenylamines (TPA) and pyridine-derivatized TPAs as the electron-donating components, and alkynyl derivatives of 2,1,3-benzothiadiazole and cyclopentadithiophenone as the electron acceptors. The complexes containing the pyridine-derivatized ligands were prepared to examine the effect that direct coordination of a heteroatom-modified TPA may have on the electronic properties of donor-acceptor (D-A) complexes. Four complexes composed of meta- and para- pyridine-derivatized TPAs were prepared, and their electronic properties were compared with three structurally similar complexes composed of TPA, as well as with purely organic D-A compounds. Data collected from UV-vis and cyclic voltammetry show minor differences on the properties of the complexes containing the pyridine-derivatized ligands when compared to the TPA analogs, exhibiting similar highest occupied molecular orbital-lowest unoccupied molecular orbital bandgaps ranging from 2.156 to 2.705 eV for the pyridine-derivatized complexes (6a,b and 7a,b), 2.038-2.320 eV for the TPA complexes (8a,b and 9a), 2.301 eV for organic molecule 10a, and 1.997 eV for 10b. All compounds are stable, exhibiting no decomposition in the solid indefinitely, and only minor decomposition in solution. All compounds were characterized by ¹H and ¹³C nuclear magnetic resonance, infrared spectroscopy, and electrospray mass spectrometry. All complexes were also characterized by ³¹P nuclear magnetic resonance and elemental analysis of CHN; determination of Ag content for 6a,b and 7a,b (carried through the synthetic steps) was determined by inductively coupled plasma optical emission spectrometry. The para-pyridine-derivatized complex of 2,1,3-benzothiadiazole (6a) was further characterized by X-ray crystallography as a AgNO₃ clathrate. X-ray quality crystals were grown from a solution of hexanes/CH ₂Cl₂ and from diffusion of hexanes into a CH ₂Cl₂ solution of the complex, providing a solvent-free crystal and a solvate of CH₂Cl₂, respectively.

Full text of DOI:10.1021/ic500290m

Article
pubs.acs.org/IC
Synthesis and Characterization of Electron Donor−Acceptor
Platinum(II) Complexes Composed of N,N‑Diphenylpyridineamine
and Triphenylamine Ligands
Zhi Dai, Alejandro J. Metta-Magan
̃
̃
a, and Jose E. Nunez*
Department of Chemistry, University of Texas at El Paso, 500 W. University Avenue, El Paso, Texas 79968, United States
*
S Supporting Information
ABSTRACT: The synthesis and electronic properties of a series of platinum(II) complexes
composed of electron-donor and electron-acceptor components as potential photovoltaic
materials is reported. The complexes are composed of triphenylamines (TPA) and pyridine-
derivatized TPAs as the electron-donating components, and alkynyl derivatives of 2,1,3-
benzothiadiazole and cyclopentadithiophenone as the electron acceptors. The complexes
containing the pyridine-derivatized ligands were prepared to examine the effect that direct
coordination of a heteroatom-modified TPA may have on the electronic properties of donor−
acceptor (D−A) complexes. Four complexes composed of meta- and para- pyridine-derivatized
TPAs were prepared, and their electronic properties were compared with three structurally
similar complexes composed of TPA, as well as with purely organic D−A compounds. Data collected from UV−vis and cyclic
voltammetry show minor differences on the properties of the complexes containing the pyridine-derivatized ligands when
compared to the TPA analogs, exhibiting similar highest occupied molecular orbital−lowest unoccupied molecular orbital
bandgaps ranging from 2.156 to 2.705 eV for the pyridine-derivatized complexes (6a,b and 7a,b), 2.038−2.320 eV for the TPA
complexes (8a,b and 9a), 2.301 eV for organic molecule 10a, and 1.997 eV for 10b. All compounds are stable, exhibiting no
1
decomposition in the solid indefinitely, and only minor decomposition in solution. All compounds were characterized by H and
1
3
C nuclear magnetic resonance, infrared spectroscopy, and electrospray mass spectrometry. All complexes were also
3
1
characterized by P nuclear magnetic resonance and elemental analysis of CHN; determination of Ag content for 6a,b and 7a,b
carried through the synthetic steps) was determined by inductively coupled plasma optical emission spectrometry. The para-
(
pyridine-derivatized complex of 2,1,3-benzothiadiazole (6a) was further characterized by X-ray crystallography as a AgNO3
clathrate. X-ray quality crystals were grown from a solution of hexanes/CH Cl and from diffusion of hexanes into a CH Cl
2
2
2
2
solution of the complex, providing a solvent-free crystal and a solvate of CH Cl , respectively.
2
2
INTRODUCTION
potential applications in diverse areas as multifunctional
materials. The model compounds reported in this work will
serve as small molecule references for extended, polypyridyl
metallic structures.
■
2
Platinum(II) complexes have been investigated for a variety of
applications, including the study of solid-state molecular
1
2
dynamics, photo- and electroluminescence, and charge-
3
In this Article we report the synthesis and characterization of
cationic complexes 6a,b and 7a,b composed of meta- and para-
pyridine-derivatized TPAs, Figure 2, neutral alkynyl-TPA
complexes 8a,b, and TPA complex 9a (complex 9b could not
be synthesized following known conditions), as well as purely
organic compounds 10a,b, and report the photophysical
properties as determined by UV−vis and emission experiments,
as well as by cyclic voltammetry, from which their electronic
highest occupied molecular orbital−lowest unoccupied molec-
ular orbital (HOMO−LUMO) bandagaps were determined.
The measured bandgaps range from 2.156 to 2.705 eV for
pyridine-derivatized TPA complexes 6a,b and 7a,b and from
transfer (CT) polymers, particularly dialkynyl complexes of
Pt(II), the photoactive properties of which can be tuned by
structural modifications of the ligands. Triphenylamine (TPA)
derivatives such as 1−3, Figure 1, have also been studied in the
area of photovoltaic materials and have demonstrated efficient
electron-transfer properties within polymers, dendrimers, and
metallic assemblies such as 4 and 5.
have been extensively studied as potential components in
4
3
−6
Although TPA analogs
7
electron-transfer materials, pyridine derivatives of TPA,
capable of functioning as coordination ligands, as well as
electron-transfer components, are unknown. The ability to
control the relative orientation of the electron donor and
acceptor through self-assembly into well-defined structures is
2
.038 to 2.320 eV for TPA complexes 8a,b and 9a. The
measured bandgap for organic compound 10a is 2.301; it is
.997 eV for 10b. All of these compounds were prepared to
8
expected to lead to improved electron-transfer efficiencies. For
1
this work, platinum acetylide complexes were chosen as initial
models due to their stability, as well as for additional
photophysical properties, such as phosphorescent excited states,
and efficient electron transfer, which provide them with
Received: February 6, 2014
Published: June 27, 2014
©
2014 American Chemical Society
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Figure 1. Triphenylamine polymers, dendrimers, and dialkynyl platinum(II) polymers. −6
2
Figure 2. Pyridine-derivatized TPA complexes, neutral TPA complexes, and organic analogues.
investigate the potential effect that the pyridine-derivatized
TPA ligands in complexes 6 and 7 may have on the
photophysical properties. Determination of equal, or improved,
photophysical properties of pyridine-derivatized TPAs, when
compared to the more typically used TPA donors, may lead to
extended structures with enhanced electron-donating and
RESULTS AND DISCUSSION
■
Synthesis of 2,1,3-Benzothiadiazole Derivatives. 2,1,3-
Benzothiadiazole derivatives of compounds 6a−10a were
prepared by initial bromination of commercially available
,1,3-benzothiadiazole to provide monobromo product 11,
Scheme 1, under reported conditions using hydrobromic acid
2
-
accepting capabilities. We anticipate that electron-donating
and Br , followed by a Pd-catalyzed Sonogashira coupling
2
pyridine derivatives, such as those presented in this work, will
serve as useful building blocks for the formation of well-defined
metallic assemblies in which the relative position of electron
donors and acceptors can be controlled through the formation
reaction of 11 with commercially available 2-methyl-3-butyn-2-
4
,9
ol to give compound 12 in 65% yield.9 Deprotection of 12
e,10
under basic conditions gave alkynyl 13,
which was coupled
with trans-[PtCl (PEt ) ] under copper-catalyzed conditions, as
2
3 2
1
reported for improved coupling reactions of terminal acetylenes
of extended structures. All complexes were characterized by H,
8a
1
3
31
with platinum chloride, to give chloro complex 14 in 35%
yield, which was then converted to nitrato complex 15 by
C, and P nuclear magnetic resonance, infrared spectroscopy,
electrospray mass spectrometry, and elemental analysis of
CHN. Determination of Ag content for 6a,b and 7a,b (carried
through the synthetic steps) was determined by inductively
coupled plama optical emission spectrometry (ICP-OES). Two
crystal structures of complex 6a were characterized by X-ray
crystallography, as described in the Results and Discussion
section as well as in the Supporting Information; one as a
solvent-free structure formed from a solution of hexanes and
CH Cl and the other as a CH Cl solvate from diffusion of
8b−e
reaction with silver nitrate.
Substitution reaction of nitrato
1
5 with the corresponding meta- or para-pyridine-derivatized
8
TPA gave the target complexes in 90% yields, as depicted in
Scheme 1 for para-ligand 16. The meta- and para-pyridine-
derivatized TPA ligands were synthesized as reported in the
11
literature.
Synthesis of Cyclopentadithiophenone Derivatives.
Cyclopentadithiophenone derivatives for complexes 6b−8b
and 10b were prepared following reported conditions for the
synthesis of monobromo cyclopentadithiophenone 17, starting
2
2
2
2
hexanes into a CH Cl solution of the complex.
2
2
7
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Inorganic Chemistry
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Scheme 1. Synthesis of Pyridine-Derivatized TPA Complexes
Scheme 2. Synthesis of TPA Species
1
2
from commercially available 3-bromothiophene, Scheme 1.
crystal structure of 6a, described below, as well as in the
Supporting Information.
Compound 17 was functionalized through a Sonogashira
coupling reaction with 2-methyl-3-butyn-2-ol to give 18 in
Synthesis of TPA Species 8a,b, 9a, and 10a,b. Complex
8a was prepared through a coupling reaction of known alkyne
22 under palladium-catalyzed coupling conditions with
9
c,d,10
2
5% yield.
terminal alkyne 19, which was then coupled with trans-
PtCl (PEt ) ] to give chloro complex 20 in 33% yield, which
Deprotection of 18 under basic conditions gave
9c,d,10
[
complex 14 to give 8a in 58% yield, Scheme 2.
Alkynyl
2
3 2
was converted to nitrato complex 21 by reaction with silver
nitrate. Substitution reaction of nitrato 21 with the
TPA 22 was prepared by an initial coupling reaction of known
bromo-TPA 23 with 2-methyl-3-butyn-2-ol to give alcohol 24
8
corresponding meta- or para-N,N-diphenylpyridineamine gave
the target complexes (6b and 7b) in 90% yields, as depicted in
in 65% yield, followed by a base-catalyzed deprotection reaction
8
9f,13
to give 22 in 46% yield.
Complex 8b was synthesized under
Scheme 1 for substitution using ligand 16.
Complexes 6a,b and 7a,b contained residual Ag carried
through the reaction sequence (from the reaction with
similar conditions, by coupling 22 with chloro complex 20 to
give 8b in 42% yield. Compound 9a was prepared by initial
+
13
lithiation of monobromo TPA 23, followed by addition of
14
AgNO ), ranging from 0.4 to 7.1%, as described in the
complex 14 to yield 9a in 23% yield. Complex 9b could not
be prepared following reported conditions for similar
complexes. Bromo-TPA derivative 23 was also subjected to a
palladium-catalyzed reaction with alkyne 13, to produce 10a in
41% yield. Analogue 10b was prepared in 26% yield through a
similar Pd-catalyzed coupling reaction of 23 with alkynyl
cyclopentadithiophenone 19.
3
Experimental Section, and could not be completely removed.
However, on the basis of the similarity of the photophysical
data collected for all compounds in solution, it is presumed that
the presence of the Ag ion does not affect the photophysical
properties of these complexes in solution. This is also
+
supported by the weak interactions observed for Ag in the
7
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Figure 3. Crystal structures of (a) solvent-free 6a and (b) CH Cl clathrate of 6a.
2
2
Table 1. UV−vis at 10− M and Extinction Coefficients, λabs
5
X-ray Crystallography. Solvent-Free Crystal Structure of
a. The geometry at the Pt center in this complex displays the
6
in nm (log ε)
expected square planar coordination sphere, with the two
phosphine ligands in a trans orientation, with the ethyl groups
in a staggered conformation, and exhibiting typical Pt−P bond
lengths (2.32 Å), Figure 3, and Table S3 in the Supporting
Information. The N-pyridyl group is not coplanar with the
alkynyl benzothiadiazole group but is tilted by 17°, presumably
due to the steric effects caused by the coordination of the
alkyne to the Ag cation. The use of the benzothiadiazole in the
alkyne ligand makes easier the fixation by coordination of the
Ag cation to the alkyne. The coordination observed between
the Ag cation and the alkyne is well-known to occur in which a
longer distance is observed between the carbon α to the
aromatic ring than to the β (average distances are 2.429 and
compound
CH Cl2
toluene
317 (4.07),
THF
2
13
231 (4.34), 309 (4.06)
16 (4.27), 341 (3.77)
316 (3.80),
341 (3.77)
3
342 (3.79)
14
249 (4.34), 283 (4.12)
312 (4.17), 413 (4.00)
312 (4.12),
320 (4.13)
311 (4.15),
319 (4.17)
417 (3.98)
4
18 (3.95)
289 (4.46),
87 (3.42)
1
2
9
0
488 (4.56), 489 (3.41)
296 (4.28),
487 (3.41)
4
291 (4.17), 352 (4.14)
564 (3.34)
292 (4.28),
346 (4.21)
291 (4.30),
347 (4.23)
563 (3.38)
5
59 (3.41)
305 (4.50),
03 (3.96)
6
6
a
306 (4.43), 387 (3.92)
288 (4.44), 545 (3.32)
305 (4.47), 388 (4.00)
287 (4.53), 545 (3.32)
346 (4.48), 423 (4.10)
302 (4.37), 367 (4.52),
298 (4.47),
402 (3.94)
4
b
300 (4.37),
550 (3.36)
299 (4.42),
551 (3.40)
15
1
2
2.798 Å, respectively); behaving more as an η than as an η .
7a
299 (4.47),
298 (4.55),
403 (4.05)
4
03 (3.97)
299 (4.46),
52 (3.38)
In the case of complex 6a, the observed distances vary slightly,
showing distances of 2.477(6) and 2.636(7) Å, with a close
contact to Pt of 3.206(3) Å. The Ag cation also coordinates to
both nitrate counterions in a bidentate and monodentate
fashion. There is a close contact to the Pt of 3.206(3) Å, but as
we discuss below it seems to be only that, a close contact (steric
interaction) without any bonding interaction.
7
8
b
a
294 (4.53),
551 (3.38)
5
320 (4.43),
426 (4.04)
319 (4.40),
425 (4.01)
8b
363 (4.44),
561 (3.32)
362 (4.47),
565 (3.31)
5
69 (3.31)
9
1
1
a
306 (4.37), 422 (4.04)
312 (4.29), 422 (4.13)
297(4.54), 364(4.63),
306 (4.55),
305 (4.60),
424 (4.01)
4
23 (3.96)
Dichloromethane Clathrate of 6a. The presence of the
CH Cl of solvation in the crystal clathrate of 6a affects the
0a
0b
318 (4.41),
423 (4.09)
317 (4.40),
418 (4.10)
2
2
362 (4.49),
526 (3.60)
361 (4.55),
525 (3.63)
binding of the benzothiadiazole to the Ag cation through an
induced rotation along the triple bond, thus exhibiting a greater
tilt with respect to the N-pyridyl group of 32.2°, as compared to
the solvent-free structure, Figure 3. The coordination distances
from Ag to the alkyne are more symmetrical, displaying a more
5
31(3.66)
spectra for pyridine-derivatized TPA complexes 6a and 6b are
presented in Figure 4. Both para- and meta-ligands exhibit
absorption signals at λmax = 300 nm (not shown), which are
assigned to π−π* transitions, with no other feature in their
2
η coordination mode than the solvent-free structure, with Ag-
alkyne distances of 2.398(11) and 2.472(12) Å. This change in
the coordination of Ag to the alkyne is a consequence of the
absent interactions between Ag with benzothiadiazole and the
Pt center. In this structure, there is no change between the
coordination of the Ag cation with the nitrates, as compared to
the solvent-free structure. However, the Ag−Pt distance is
longer (3.3827(6) Å), and there are no differences on the bond
lengths of the ligands coordinated to Pt, suggesting a very weak
interaction of the Ag ion on the solvent-free structure.
16
spectra. Absorption bands in the near-UV region (∼375 nm)
are assigned to metal-to-ligand charge transfer transitions
1
6d,f
(
MLCT), as reported for related complexes.
This assign-
ment is also consistent with the lack of solvent sensitivity
observed for these complexes, as well as with the blue-shifted
absorptions observed for the pyridine-derivatized TPA
16b,d,17
complexes when compared to the Pt−Cl precursors.
Benzothiadiazole complexes 6a−9a: transitions in the range
of 283−388 nm were also observed for compounds 6a−9a and
Electronic Properties. UV−vis Absorption. The UV−vis
absorption in various organic solvents was measured at 25 °C.
These values are presented in Table 1, and representative
1
6,17
chloro complex 14, ascribed to π−π* transitions;
however,
complex 14 displays a signal at 413 nm, characteristic of MLCT
7
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Figure 4. UV−vis spectra of pyridine-derivatized TPA complexes 6a (a) and 6b (b).
Figure 5. Emission spectra of pyridine-derivatized TPA complexes 6a (a) and 6b (b).
transitions for complexes of Pt−Cl, as reported by Mdleleni et
which are consistent with absorptions of reported compounds
1
6d
5,16,17
al. Complexes 6a−7a also exhibit a signal in the range of
containing extended structures of benzothiadiazole
as well
12b
3
87−422 nm (blue-shifted relative to 14), which we interpret
as for those of alkynyl cyclopentadithiophenone.
Emission Spectra. Emission experiments were performed in
as an effect of the electron-withdrawing nature of the pyridine
−5
ligand on Pt, presumably lowering the HOMO level of the Pt,
CH Cl , at 10 M (Figure 5). All complexes of cyclo-
2 2
5,16,17
thus increasing the HOMO−LUMO gap for MLCT.
the other hand, complexes 8a and 9a exhibit red-shifted signals
423 nm), consistent with complexes containing an extended
On
pentadithiophenone (6b−8b) were blue emitters, with
emission maxima ranging from 400 to 403 nm, when excited
at their highest energy absorption bands (287−302 nm), as
(
1
6d,e
conjugation.
described for similar Pt complexes.
Benzothiadiazole
Cyclopentadithiophenone complexes 6b−8b: transitions in
complexes containing the pyridine-derivatized TPAs (6a and
7a) emitted in the range of 466−468 nm when excited at their
lowest energy absorption band (388 nm); however, benzothia-
diazole complexes of TPA (8a and 9a) emitted at 438 and 402
nm, respectively, when excited at their highest energy
absorption bands (346 nm for 8a and 306 nm for 9a).
Contrary to the metallic analogues, organic compounds 10a
and 10b demonstrated a dependence on the nature of the
electron-acceptor, in which 10a exhibited an emission band at
612 nm when excited at its lowest energy absorption (422 nm),
whereas excitation of 10b at its highest energy absorption (364
nm) induced emission at 413 nm.
the range of 288−367 nm were observed for compounds 6b−
8
b, as well as for chloro complex 20, consistent with reported
16
π−π* transitions; complex 20 also displays a signal at 564
nm, assigned to MLCT transitions, as reported for complexes
12
of alkynyl cyclopentadithiophenones. Similar to the benzo-
thiadiazole analogs, cyclopentadithiophenone complexes 6b
and 7b also exhibit blue-shifted signals (545 nm) relative to
chloro precursor 20 (564 nm) presumably due to the electron-
withdrawing effect of the pyridine-derivatized ligand on Pt,
causing an increase in the HOMO−LUMO gap of the MLCT
5
,12b,16,17
in these complexes.
As expected, complex 8b exhibits a
red-shifted signal (569 nm) that is consistent with its extended
conjugation.
No absorption differences were observed between the meta-
Cyclic Voltammetry. The cyclic voltammetry of all
compounds was performed in ortho-dichlorobenzene solutions
(0.05 M n-Bu NPF ) with ferrocene as the internal potential
4
6
and para-analogues of the benzothiadiazole complexes (6a and
standard. The measured bandgaps for the compounds are listed
in Table 2, and their corresponding voltammograms are shown
in the Supporting Information. Oxidation presumably occurs
from the one-electron oxidation of the tertiary amine center at
7a) or between those of cyclopentadithiophenone (6b and 7b).
Organic compounds 10a and 10b exhibit π−π* transitions,
along with signals at 422 nm for 10a and 531 nm for 10b,
7
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Inorganic Chemistry
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gel thin layer chromatography using silica gel plates 60 F254 (EMD)
and visualized under UV light (254 nm). Compound purifications
were performed using 63−200 mesh 60 Å silica gel (EMD). Moisture-
sensitive reactions were carried out in oven-dried glassware under a
dinitrogen atmosphere, using standard Schlenk techniques. THF was
Table 2. Bandgaps Measured from the Onset of Oxidation
and Reduction Potentials
1
9
19
compounds
band gap (eV)
compounds
band gap (eV)
6
7
8
9
1
a
2.705
2.644
2.320
2.180
2.301
6b
7b
8b
2.264
2.156
2.038
distilled from sodium (Sigma-Aldrich), and Et NH (Sigma-Aldrich)
a
2
was dried from potassium hydroxide (Sigma-Aldrich); both solvents
a
1
13
31
were degassed under N for 30 min before use. H, C, and P NMR
2
a
1
spectra were obtained with a JEOL 600 MHz spectrometer. The H
and C NMR chemical shifts are reported relative to residual solvent
signals, and P NMR resonances are referenced to an internal
0a
10b
1.997
13
31
the pyridine-derivatized TPA ligands in complexes 6a,b and
standard sample of 85% H PO (δ = 0.0). Fourier transform infrared
3
4
7
1
a,b and from the TPA ligands in compounds 8a−10a, 8b, and
(FTIR) spectra were obtained with a PerkinElmer FT-IR spectrum-
100 spectrometer (equipped with ATR accessory) as neat solids or
oils. Melting points were measured on a Mel-Temp melting point
apparatus (1002D) and are uncorrected. High-resolution mass spectra
0b, as reported for D−A compounds containing a TPA
3
−6
electron donor.
Pyridine-derivatized complexes 6a,b and
7
a,b undergo oxidation at a higher potential than the other
compounds, ranging from 0.707 to 1.141 V, whereas complexes
a,b and 9a range from 0.181 to 0.376 V, and organic
(HRMS) were acquired by electrospray ionization (ESI) measured on
a Jeol AccuTOF JMS-T100LC ESI-MS spectrometer calibrated with
PEG-600. UV−vis spectra were recorded on a Cary 50Bio UV−vis
spectrophotometer.
Synthesis of Alkynyl Alcohol 2,1,3-Benzothiadiazole 12.
Under a dinitrogen atmosphere, a solution of compound 11 (930 mg,
8
compounds 10a,b range from 0.493 to 0.593 V. The higher
potential for electron removal of complexes 6 and 7 is
interpreted to be a consequence of the electron-withdrawing
effect of the pyridine substituent on the pyridine-derivatized
TPA ligands, making electron removal at the tertiary amine
center less efficient when compared with the TPA analogs.
Minor differences were observed between the measured
bandgaps of meta- and para-pyridine-derivatized TPA com-
plexes of benzothiadiazole (6a and 7a; Δ = 0.061 eV) as well as
for those of cyclopentadithiophenone (6b and 7b; Δ = 0.108
eV). The measured bangaps also show little dependence on the
nature of the electron acceptor, with bandgaps differing by
4
.44 mmol), 2-methyl-3-butyn-2-ol (756 mg, 9.00 mmol),
PdCl (PPh ) (20 mg, 0.03 mmol), copper iodide (20 mg, 0.105
2
3 2
mmol), and triphenylphosphine (50 mg, 0.191 mmol) were added to a
triethylamine/dichloromethane solution (10 mL/10 mL), and the
resulting suspension was stirred at 70 °C for 12 h. The solvent was
evaporated, and the crude was purified by column chromatography
using 1:2 v/v Et O/hexanes, affording 63 mg of 12 in 65% yield as a
2
1
brown oil. H NMR (600 MHz, CDCl , trimethylsilane (TMS)): δ
3
1
7
.51 (s, 1H, −OH), 1.69 (s, 6H, CH ), 7.46 (t, J = 9.0 Hz, 1H, Ar−H),
3
13
.61 (d, J = 7.2 Hz, 1H, Ar−H), 7.89 (d, J = 7.2 Hz, 1H, Ar−H).
C
0.441 eV for complexes 6a versus 6b and by 0.488 eV for
NMR (150 MHz, CDCl ): δ 31.49, 65.63, 77.34, 100.90, 116.77,
3
complexes 7a versus 7b.
1
1
21.61, 129.38, 132.72, 154.59. FTIR (oil): 3387, 3058, 2980, 2932,
+
538, 1488, 1361. HRMS calcd for C H N OS (M ) 218.0514;
11
10
2
CONCLUSIONS
+
■
found (ESI): 219.0534 (M+H ).
A series of compounds composed of pyridine-derivatized TPAs
as electron-donating components and either 2,1,3-benzothia-
diazole or cyclopentadithiophenone as the electron acceptors
Synthesis of Compound 13. Under a dinitrogen atmosphere,
powdered potassium carbonate (925 mg, 6.70 mmol) and 18-crown-6
(100 mg, 0.38 mmol) were added to a solution of compound 12 (0.63
g, 2.89 mmol) in dry toluene (20 mL). The reaction mixture was
heated to reflux for 1 h. After it was cooled to room temperature, the
mixture was poured into water (50 mL) and extracted with
dichloromethane (2 × 15 mL). The solvent was evaporated, and the
crude product was purified using column chromatography with 1:10 v/
(6a,b and 7a,b) were synthesized, and their photophysical
properties were determined by UV−vis and emission experi-
ments, as well as by cyclic voltammetry, from which their
electronic HOMO−LUMO bandagaps were determined. These
compounds were prepared to test the potential effect that a
pyridine-derivatized TPA functioning as an electron donor may
have on the photophysical properties of the complexes. To test
the potential effects, analogous TPA complexes 8a,b, and 9a
were prepared and similarly studied. All complexes exhibited
comparable HOMO−LUMO bandgaps (2.156−2.705 eV for
v Et O/hexane to give 13 in 46% yield as a light yellow solid. This
2
9e
compound matched reported characterization.
Synthesis of Compound 14. Under a dinitrogen atmosphere,
alkynyl benzothiadiazole 13 (53 mg, 0.33 mmol) and trans-
[PtCl (PEt ) ] (331 mg, 0.66 mmol) were added to a mixture of
2
3 2
triethylamine/dichloromethane (10 mL/10 mL) in the presence of a
catalytic amount of CuI (20 mg, 0.105 mmol). The reaction mixture
was stirred at room temperature overnight. The solvent was then
removed under reduced pressure to obtain the crude product. The
6a,b and 7a,b and 2.038−2.320 eV for 8a,b and 9a), thus
indicating no major effect on the properties of the complexes
when a pyridine-derivatized electron donor is incorporated in
the D−A complexes. This study suggests that electron donor−
acceptor complexes composed of extended pyridine-derivatized
TPA ligands as the electron-donating components hold
promise as potentially useful photovoltaic materials. Photo-
physical studies on extended structures will be reported soon.
mixture was purified by chromatography using 1:8 (v/v) Et O/hexane
2
as the eluent to produce 73 mg of 14 in 35% yield as a yellow solid, mp
1
8
1
7
1
8−90 °C (dec). H NMR (600 MHz, CDCl , TMS) δ 1.19−1.23 (m,
3
8H, CH ), 2.14−2.15 (m, 12H, CH ), 7.40−7.43 (m, 2H, Ar−H),
3
2
13
.77−7.79 (m, 1H, Ar−H). C NMR (150 MHz, CDCl ) δ 7.93,
3
3
1
4.67, 93.04, 98.23, 118.39, 122.54, 129.68, 130.08, 155.15, 156.29.
P
NMR (CDCl , 243 MHz): δ 15.86 (s, J
= 1177.51 Hz). IR (solid):
3
Pt−P
EXPERIMENTAL SECTION
2
C
958, 2925, 2854, 2109,1730, 1526, 1455. HRMS calcd for
■
+
+
General Experimental. All materials were used as received, unless
specified. [4-amino pyridine, 18-crown-6 (Sigma-Aldrich), bromoben-
zene, copper iodide (Alfa Aesar), 4-amino pyridine (TCI America),
hexanes (Macron Chemicals), diethyl ether, acetone, potassium
carbonate (BDH), dichloromethane, tetrahydrofuran (THF)
EMD)]. Reaction solvents were dried over 4 Å molecular sieves
EMD) at least 24 h before use, or collected from a solvent
20
H33ClN
2
P
2
PtS (M ) 625.1176; found (ESI): 625.1192 (M ).
Synthesis of Nitrato Complex 15. Under a dinitrogen
atmosphere, compound 14 (20 mg, 0.032 mmol) and silver nitrate
(21 mg, 0.120 mmol) were added to chloroform (10 mL) in the dark.
The reaction mixture was stirred at room temperature overnight. The
solid was filtered off. The solvent was then removed under reduced
pressure to obtain 21 mg of 15 in essentially quantitative yield as a
yellow solid.
(
(
purification system (MBRAUN). Reactions were monitored by silica
7
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Inorganic Chemistry
Article
Synthesis of Compound 6a. Under a dinitrogen atmosphere,
compound 15 (20 mg, 0.032 mmol) and para-pyridine-derivatized
TPA 16 (7.9 mg, 0.032 mmol) were added to dry toluene (10 mL).
The reaction was stirred for 12 h. The solvent was removed under
reduced pressure. The residue was redissolved in dichloromethane
was evaporated, and the crude product chromatographed using 1:2 (v/
v) diethyl ether/hexane as the eluent, giving 22 mg of 8a in 58% yield
1
as a yellow solid, mp 114−116 °C (dec). H NMR (600 MHz, CDCl ,
3
TMS) δ 1.23−1.26 (m, 18H, CH ), 2.27−2.28 (m, 12H, CH ), 6.93
3
2
(d, J = 8.4 Hz, 2H, Ar−H), 6.98 (t, J = 6.8 Hz, 2H, Ar−H), 7.08 (d, J =
7.5 Hz, 4H, Ar−H), 7.18 (d, J = 7.5 Hz, 2H, Ar−H), 7.22 (t, J = 7.5
Hz, 2H, Ar−H), 7.41−7.45 (m, 2H, Ar−H), 7.76−7.77 (m, 1H, Ar−
(
0.5 mL) and washed with 0.5 mL H O. The solvent was then
2
evaporated under a flow of nitrogen, and the residue was washed with
0 mL of diethyl ether to give 24 mg of 6a in 90% yield as a yellow
2
H). 13C NMR (150 MHz, CDCl ) δ 8.53, 16.55, 105.71, 106.41,
3
1
solid, mp 150−152 °C (dec). H NMR (600 MHz, CD COCD ) δ
1
109.79, 118.08, 122.57, 124.06, 129.21, 129.81, 129.97, 131.84, 145.05,
3
3
.18−1.21 (m, 18H, CH ), 2.03−2.04 (m, 12H, CH ), 6.86 (d, J = 6.0
147.85, 155.18, 156.38. 31P NMR (CDCl , 243 MHz): δ 12.02 (s, J
3
2
3
Pt−P
Hz, 2H, Ar−H), 7.36−7.41 (m, 6H, Ar−H), 7.50−7.53 (m, 4H, Ar−
= 1177.51 Hz). IR (solid): 3022, 2965, 2927, 2876, 2852, 2094, 1733,
+
H), 7.61 (t, J = 9.0 Hz, 1H, Ar−H), 7.65 (d, J = 8.8 Hz, 1H, Ar−H),
1587, 1489. HRMS calcd for C H N P PtS (M ) 858.2614; found
40
47
3 2
1
3
+
7
.65 (d, J = 9.0 Hz, 1H, Ar−H), 8.38 (d, J = 6.0 Hz, 2H, Ar−H).
C
(ESI): 858.2621 (M ). Elemental analysis found: C, 55.21; H, 5.87; N,
4.46. Calcd for C H N P PtS: C, 55.93; H, 5.51; N, 4.89%.
NMR (150 MHz, CD COCD ) δ 7.97, 14.62, 82.54, 102.93, 113.15,
3
3
40 47
3 2
1
1
19.53, 120.24, 127.02, 127.22, 127.85, 129.74, 130.60, 131.19, 142.84,
Synthesis of Compound 10a. Under a dinitrogen atmosphere,
alkynyl benzothiadiazole 13 (53 mg, 0.33 mmol) and bromo TPA 23
(225 mg, 0.69 mmol) were added to a solution of triethylamine/
dichloromethane (10 mL/10 mL), PdCl (PPh ) (10 mg, 0.014
mmol), triphenylphosphine (15 mg, 0.06 mmol), and copper iodide
(20 mg, 0.105 mmol). The reaction mixture was stirred at room
temperature overnight. The solvent was then removed under reduced
pressure. The crude was purified by column chromatography using
51.24, 154.62, 155.69. 31P NMR (CD COCD , 243 MHz): δ 16.68
3
3
(
s, JPt−P = 1157.80 Hz). IR (solid): 3059, 2960, 2924, 2853, 2118,
731, 1620, 1590, 1489. HRMS calcd for C H N P PtS (M )
+
1
8
4
4
37 47 4 2
2
3 2
+
36.2639; found (ESI): 836.2648 (M ). Elemental analysis found: C,
3.32; H, 4.74; N7.89; Ag, 6.40. Calcd for C H AgN O P PtS: C,
37
47
6
6 2
1.58; H, 4.43; N, 7.86; Ag, 10.09%.
Synthesis of Compound 7a. Under a dinitrogen atmosphere,
compound 15 (20 mg, 0.032 mmol) and meta-pyridine-derivatized
TPA (7.9 mg, 0.032 mmol) were dissolved in dry toluene (10 mL).
The reaction was stirred for 12 h. The solvent was removed under
reduced pressure. The residue was dissolved in 0.5 mL of
1:10 (v/v) Et O/hexane to produce 54 mg of 10a in 41% yield as a
2
1
yellow solid, mp 66−68 °C. H NMR (600 MHz, CDCl , TMS) δ
3
7.03 (d, J = 8.4 Hz, 2H, Ar−H), 7.07 (t, J = 7.6 Hz, 2H, Ar−H), 7.14
(d, J = 7.5 Hz, 4H, Ar−H), 7.28 (t, J = 7.5 Hz, 4H, Ar−H), 7.51 (d, J =
9.5 Hz, 2H, Ar−H), 7.54−7.56 (m, 1H, Ar−H), 7.75 (d, J = 6.8 Hz,
dichloromethane and washed with 0.5 mL of H O. Then the solvent
2
13
was removed under a flow of nitrogen, and the residue was washed
1H, Ar−H), 7.95 (d, J = 8.9 Hz, 1H, Ar−H). C NMR (150 MHz,
with 20 mL diethyl ether to produce 24 mg of 7a in 90% yield as a
CDCl ) δ 84.63, 96.57, 115.26, 117.70, 121.39, 122.02, 123.87, 125.28,
3
1
yellow solid, mp 156−158 °C (dec). H NMR (600 MHz,
129.39, 129.56, 132.27, 133.08, 147.16, 148. 60, 154.71, 154.76. IR
CD COCD ) δ 1.13−1.16 (m, 18H, CH ), 2.02−2.03 (m, 12H,
(solid): 3036, 2201, 1724, 1585, 1537, 1487. HRMS calcd for
3
3
3
+
+
CH ), 7.27−7.29 (m, 6H, Ar−H), 7.44−7.47 (m, 4H, Ar−H), 7.57−
C H N S (M ) 403.1143; found (ESI): 404.1156 (M+H ).
26 17 3
2
7
.67 (m, 4H, Ar−H), 7.85−7.87 (m, 1H, Ar−H), 8.10−8.13 (m, 1H,
Synthesis of Compound 10b. Under a dinitrogen atmosphere,
compound 19 (55 mg, 0.20 mmol) and compound 23 (100 mg, 0.37
mmol) were added to a mixture of triethylamine/dichloromethane (10
1
3
Ar−H), 8.42−8.43 (m, 1H, Ar−H). C NMR (150 MHz,
CD COCD ) δ 7.37, 14.10, 84.50, 102.37, 119.56, 120.81, 126.09,
3
3
1
1
1
1
28.10, 129.32, 129.82, 130.28, 130.39, 131.03, 143.24, 144.44, 148.01,
mL/5 mL) in the presence of Pd(OAc) (15 mg, 0.07 mmol), CuI (12
2
54.93, 155.95. 31P NMR (CD COCD , 243 MHz): δ 17.03 (s, J
=
Pt−P
mg, 0.60 mmol), and triphenylphosphine (15 mg, 0.06 mmol). The
reaction mixture was refluxed overnight. The solvent was then
removed under reduced pressure to obtain the crude product. The
3
3
157.77 Hz). IR (solid): 3059, 2960, 2925, 2853, 2121, 1733, 1587,
+
566, 1484, 1333. HRMS calcd for C H N P PtS (M ) 836.2639;
37
47
4 2
+
found (ESI): 836.2654 (M ). Elemental analysis found: C, 42.81; H,
crude was purified by column chromatography using 1:10 (v/v) Et O/
2
4
4
.67; N, 7.93; Ag, 7.10. Calcd for C H AgN O P PtS: C, 41.58; H,
.43; N, 7.86; Ag, 10.09%.
Synthesis of Compound 9a. Under a dinitrogen atmosphere,
hexane to produce 24 mg of 10b in 26% yield as a purple solid, mp
37
47
6
6 2
1
122−124 °C. H NMR (600 MHz, CDCl , TMS) δ 6.97−6.99 (m,
3
3H, Ar−H), 7.05−7.08 (m, 4H, Ar−H), 7.11−7.12 (m, 4H, Ar−H),
1
3
compound 23 (100 mg, 0.310 mmol) was added to dry ether (10 mL).
A 2.5 M solution of n-BuLi in hexane (0.4 mL, 1 mmol) was added
dropwise at −15 °C. The resulting mixture was stirred for 1 h at −15
7.25−7.39 (m, 4H, Ar−H), 7.32−7.34 (m, 2H, Ar−H). C NMR
(150 MHz, CDCl , TMS) δ 81.54, 95.81, 114.78, 121.94, 123.93,
3
125.30, 126.37, 128.03, 129.57, 132.49, 141.61, 142.99, 147.07, 148.50,
148.71, 149.55, 182.33. IR (solid): 3083, 3036, 2192, 1704, 1585,
°C. Compound 14 (100 mg, 0.160 mmol) in 5 mL of dry ether was
+
added to the solution dropwise. The mixture was allowed to warm to
room temperature and then stirred for 1.5 h. The reaction solution was
washed with water (50 mL). The combined organic layers were dried
over MgSO . After removal of the solvent under reduced pressure, the
residue was purified by column chromatography on silica gel with 1:8
1511, 1485, 1261. HRMS calcd for C H NOS (M ) 459.0752;
found (ESI): 459.0739 (M ).
29
17
2
+
Synthesis of Compound 18. Under a dinitrogen atmosphere,
bromocyclopentadithiophenone 17 (385 mg, 1.39 mmol), 2-methyl-3-
butyn-2-ol (378 mg, 4.50 mmol), PdCl (PPh ) (20 mg, 0.03 mmol),
4
2
3 2
(
v/v) Et O/hexane as the eluent to give 31 mg of 9a in 23% yield as a
copper iodide (20 mg, 0.11 mmol), and triphenylphosphine (50 mg,
0.191 mmol) were added to a solution of triethylamine/dichloro-
methane (10 mL/10 mL), and the resulting suspension was stirred at
70 °C for 12 h. The solvent was evaporated, and the crude product
2
1
yellow solid, mp: 96−98 °C (dec). H NMR (600 MHz, CDCl ,
TMS) δ 1.09−1.14 (m, 18H, CH ), 1.89−1.91 (m, 12H, CH ), 6.83
3
3
2
(
d, J = 8.4 Hz, 2H, Ar−H), 6.89 (t, J = 7.5 Hz, 2H, Ar−H), 7.00−7.04
(
m, 4H, Ar−H), 7.16−7.19 (m, 4H, Ar−H), 7.29 (d, J = 8.4 Hz, 2H,
was chromatographed using 1:2 (v/v) Et O/hexanes, giving 95 mg of
2
13
1
Ar−H), 7.41−7.45 (m, 2H, Ar−H), 7.73−7.76 (m, 1H, Ar−H).
C
18 in 25% yield as a dark-red solid, mp 60−62 °C. H NMR (600
NMR (150 MHz, CDCl ) δ 8.24, 15.45, 106.47, 117.65, 121.11,
MHz, CDCl , TMS): δ 1.58 (s, 6H, CH ), 7.92−6.93 (m, 2H, Ar−H),
3
3
3
13
1
1
1
1
8
22.48, 126.15, 128.89, 129.71, 129.91, 139.60, 141.43, 148.55, 151.62,
7.02 (d, J = 4.8 Hz, 1H, Ar−H). C NMR (150 MHz, CDCl ) δ
3
55,24, 156.53. 31P NMR (CDCl , 243 MHz): δ 10.88 (s, J
=
Pt−P
31.39, 65.74, 75.04, 99.85, 121.88, 125.19, 125.91, 128.30, 141.23,
142.95, 149.14, 149.20, 182.26. IR (solid): 3382, 3089, 2978, 2929,
3
309.07 Hz). IR (solid): 3037, 2962, 2925, 2872, 2086, 1733, 1587,
+
+
480. HRMS calcd for C H N P PtS (M ) 834.2614; found (ESI):
2210, 1701, 1433, 1380, 1359. HRMS calcd for C H O S (M )
38
47
3
2
14 10
2 2
+
+
34.2622 (M ). Elemental analysis found: C, 59.18; H, 7.37; N, 3.93.
274.0122; found (ESI): 275.0137 (M+H ).
Calcd for C H N P PtS: C, 54.67; H, 5.67; N, 5.03%.
Synthesis of Complex 8a. Under a dinitrogen atmosphere, a
mixture of alkynyl TPA 22 (24 mg, 0.09 mmol), chloro complex 14
Synthesis of Alkynyl Cyclopentadithiophenone 19. Under a
dinitrogen atmosphere, powdered potassium hydroxide (39 mg, 0.7
mmol) and 18-crown-6 (30 mg, 0.114 mmol) were added to a solution
of 18 (95 mg, 0.348 mmol) in dry toluene (10 mL). The reaction
mixture was heated to reflux for 4 h. After it was cooled to room
temperature, the mixture was poured into water (50 mL) and extracted
38
47
3 2
(
30 mg, 0.045 mmol), and copper iodide (5 mg, 0.026 mmol) were
added to a triethylamine/dichloromethane solution (10 mL/10 mL),
and the resulting suspension was stirred at 70 °C for 12 h. The solvent
7
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Inorganic Chemistry
Article
with CH Cl (2 × 15 mL). The organic solvent was evaporated, and
NMR (CD COCD , 243 MHz): δ 16.27 (s, J = 1151.21 Hz). IR
Pt−P
2
2
3
3
the crude product was purified using column chromatography with
(solid): 3067, 2965, 2930, 2876, 2108, 1700, 1588, 1566, 1485, 1331.
+
Et O/hexane 1:10 (v/v) to give 25 mg of 19 in 33% yield as a red
HRMS calcd for C H N OP PtS (M ) 892.2247; found (ESI):
2
40 47
2
2
2
1
+
solid, mp 210−212 °C. H NMR (600 MHz, CDCl , TMS) δ 3.45 (s,
892.2265 (M ). Elemental analysis found: C, 50.35; H, 5.41; N, 4.25.
Calcd for C H N O P PtS : C, 50.31; H, 4.96; N, 4.40%. Only traces
3
1
H, CH), 6.98 (d, J = 4.8 Hz, 1H, Ar−H), 7.08−7.09 (m, 2H, Ar−
40
47
3
4
2
2
13
H). C NMR (150 MHz, CDCl ) δ 76.47, 83.51, 121.95, 124.26,
of Ag were detected by ICP-OES.
3
1
3
2
27.04, 128.54, 141.15, 143.34, 148.91, 149.66, 181.91. IR (solid):
Synthesis of Complex 8b. Under a dinitrogen atmosphere, a
mixture of compound 20 (24 mg, 0.04 mmol), alkynyl TPA 22 (31
mg, 0.12 mmol), and copper iodide (5 mg, 0.03 mmol) were added to
a triethylamine/dichloromethane solution (10 mL/10 mL), and the
resulting suspension was stirred at 70 °C for 12 h. The solvent was
evaporated, and the crude product was chromatographed using 1:2 (v/
+
305, 3278, 3231, 3081, 2167, 1703. HRMS calcd for C H OS (M )
11
4
2
+
15.9704; found (ESI): 216.9725. (M+H ).
Synthesis of Complex 20. Under a dinitrogen atmosphere, 19
25 mg, 0.116 mmol) and trans-[PtCl (PEt ) ] (115 mg, 0.23 mmol)
(
2
3 2
were added to a solution of triethylamine/dichloromethane (10 mL/
1
0 mL) in the presence of copper iodide (10 mg, 0.053 mmol). The
v) Et
yellow solid, mp 158−160 °C (dec). H NMR (600 MHz, CDCl
), 6.72
2
O/hexane as the eluent, giving 17 mg of 8b in 42% yield as a
1
reaction mixture was stirred at room temperature overnight. The
solvent was then removed under reduced pressure to obtain the crude
product. The mixture was purified by chromatography over a silica
,
3
TMS) δ 1.20−1.22 (m, 18H, CH
), 2.14−2.15 (m, 12H, CH
3
2
(s, 1H, Ar−H), 6.92−6.94 (m, 4H, Ar−H), 6.98 (t, J = 6.9 Hz, 2H,
column using 1:8 (v/v) Et O/hexane to produce 26 mg of 20 in 33%
Ar−H), 7.06 (d, J = 7.5 Hz, 4H, Ar−H), 7.14 (d, J = 6.9 Hz, 2H, Ar−
2
1
13
yield as a red solid, mp 128−130 °C (dec). H NMR (600 MHz,
H), 7.22 (t, J = 7.5 Hz, 2H, Ar−H). C NMR (150 MHz, CDCl
3
) δ
CDCl , TMS) δ 1.15−1.18 (m, 18H, CH ), 2.00−2.02 (m, 12H,
8.44, 16.64, 101.69, 105.52, 109.71, 121.33, 121.71, 122.64, 123.98,
3
3
CH ), 6.68 (s, 1H, Ar−H), 6.92 (d, J = 4.8 Hz, 1H, Ar−H), 6.95 (d, J
124.14, 126.23, 129.22, 131.78, 141.62, 142.21, 144.23, 145.18, 147.82,
2
13
31
=
4.8 Hz, 1H, Ar−H). C NMR (150 MHz, CDCl ) δ 8.12, 14.68,
150.98, 183.36. P NMR (CDCl
3
, 243 MHz): δ 11.83 (s, JPt‑P
=
3
9
1
1
1
3.58, 94.18, 121.60, 121.73, 126.57, 132.54, 141.43, 142.19, 144.59,
1177.50 Hz). IR (solid): 3082, 3059, 3033, 2962, 2926, 2853, 2872,
50.78, 183.33. 31P NMR (CDCl , 243 MHz): δ 15.78 (s, J
=
Pt−P
+
2085, 1706, 1588, 1491. HRMS calcd for C43
H
47NOP
PtS
(M )
3
2
2
+
170.94 Hz). IR (solid): 3090, 2964, 2931, 2876, 2105, 1746, 1709,
914.2222; found (ESI): 914.2234 (M ). Elemental analysis found: C,
+
453. HRMS calcd for C H ClOP PtS (M ) 681.0784; found
57.76; H, 5.96; N, 1.38. Calcd for C43
N, 1.53%.
H47NOP PtS : C, 56.44; H, 5.18;
2 2
23
33
2
2
+
(
ESI): 681.0796 (M ).
Synthesis of Complex 21. Under a dinitrogen atmosphere,
X-ray Diffraction. A specimen of each compound was mounted on
a glass fiber, and the X-ray intensity data were measured on a Bruker
SMART APEX CCD system equipped with a graphite monochroma-
tor and a Mo Kα fine-focus tube (λ = 0.710 73 Å). The frames were
integrated using a narrow-frame algorithm, and the structure was
compound 20 (26 mg, 0.038 mmol) and silver nitrate (21 mg, 0.12
mmol) were added to chloroform (10 mL) in the dark. The reaction
mixture was stirred at room temperature overnight. The solid was
filtered off. The solvent was then removed under reduced pressure to
obtain 27 mg of 21 in essentially quantitative yield as a red solid.
Synthesis of Complex 6b. Under a dinitrogen atmosphere,
compound 21 (26 mg, 0.038 mmol) and para-pyridine-derivatized
TPA 16 (9.4 mg, 0.038 mmol) were added to dry toluene (10 mL).
The reaction was stirred for 12 h. The solvent was removed under
reduced pressure. The residue was redissolved in CH Cl (0.5 mL)
18
solved and refined using the Bruker APEX2 Software Package. The
total exposure time was 4.00 h.
ASSOCIATED CONTENT
■
*
S
Supporting Information
Nuclear magnetic resonance (NMR) ( H, 13C, and 31P),
1
2
2
and washed with 0.5 mL of deionized H O. The solvent was then
removed under a flow of nitrogen, and the residue was washed with 20
mL of diethyl ether to produce 31 mg of 6b in 89% yield as a red solid,
2
infrared spectra, and mass spectra of all new compounds, UV/
vis spectra, emission spectra, cyclic voltammograms, as well as
additional crystallographic parameters for both crystal struc-
tures of 6a are available free of charge via the Internet at http://
pubs.acs.org. Crystallographic data for solvent-free 6a and
1
mp 192−194 °C (dec). H NMR (600 MHz, CD COCD ) δ 1.17−
3
3
1
6
.20 (m, 18H, CH ), 1.91−1.94 (m, 12H, CH ), 6.80 (s, 1H, Ar−H),
3
2
.83 (d, J = 7.2 Hz, 2H, Ar−H), 6.97 (d, J = 4.8 Hz, 1H, Ar−H), 7.33
(
4
d, J = 4.8 Hz, 1H, Ar−H), 7.37−7.40 (m, 6H, Ar−H), 7.50−7.52 (m,
CH Cl2 solvated 6a were deposited with the Cambridge
2
13
H, Ar−H), 8.33 (d, J = 7.2 Hz, 2H, Ar−H). C NMR (150 MHz,
Crystallographic Data Centre as supplementary publication
Nos. 983929 and 984051, respectively. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
CD COCD ) δ 7.37, 14.26, 14.37, 87.95, 98.22, 113.01, 121.13,
3
3
1
1
21.99, 127.47, 127.63, 128.77, 130.49, 131.12, 141.18, 142.30, 143,43,
45.83, 150.04, 151.84, 154.76, 182.07. 31P NMR (CD COCD , 243
3
3
MHz): δ 17.08 (s, JPt−P = 1164.36 Hz). IR (solid): 3063, 2966, 2930,
875, 2106, 1699, 1620, 1590, 1489, 1334. HRMS calcd for
2
+
+
AUTHOR INFORMATION
Corresponding Author
*E-mail: jenunez3@utep.edu.
C H N OP PtS (M ) 892.2247; found (ESI): 892.2254 (M ).
Elemental analysis found: C, 49.66; H, 5.34; N, 4.41. Calcd for
C H N O P PtS : C, 50.31; H, 4.96; N, 4.40%. Only traces of Ag
■
40
47
2
2
2
40
47
3
4
2
2
(
0.4%) were detected by ICP-OES.
Notes
Synthesis of Complex 7b. Under a dinitrogen atmosphere,
The authors declare no competing financial interest.
compound 21 (26 mg, 0.04 mmol) and meta-pyridine-derivatized TPA
9.4 mg, 0.04 mmol) were added to dry toluene (10 mL). The reaction
(
ACKNOWLEDGMENTS
was stirred for 12 h. The solvent was removed under reduced pressure.
The residue was dissolved in CH Cl (0.5 mL) and washed with 0.5
mL of deionized H O. The solvent was then removed under a flow of
nitrogen, and the residue was washed with 20 mL of diethyl ether to
produce 30 mg of 7b in 88% yield as a red solid, mp 165−167 °C
■
Generous support for this work from the National Science
Foundation PREM Program (DMR-1205302) is gratefully
acknowledged. The authors are thankful to the University of
Texas at El Paso for financial support (Start-up funds and
University Research Initiative). Z.D. acknowledges the college
of science and the chemistry department for providing funds.
We also thank the NSF Grant No. CHE-0840525 (Mass
Spectrometer), the Library, Equipment, Repair, and Rehabil-
itation (LERR) State of Texas Funding (Nuclear Magnetic
Resonance). We are thankful to the Luis Echegoyen group for
assistance with cyclic voltammetry and UV/vis experiments, as
2
2
2
1
(
dec). H NMR (600 MHz, CD COCD ) δ 1.10−1.13 (m, 18H,
3
3
CH ), 1.89−1.92 (m, 12H, CH ), 6.80 (s, 1H, Ar−H), 6.98 (d, J = 4.8
3
2
Hz, 1H, Ar−H), 7.26−7.28 (m, 6H, Ar−H), 7.33 (d, J = 4.8 Hz, 1H,
Ar−H), 7.43−7.46 (m, 4H, Ar−H), 7.62−7.64 (m, 2H, Ar−H), 8.07−
13
8
.08 (m, 1H, Ar−H), 8.41−8.42 (m, 1H, Ar−H). C NMR (151
MHz, CD COCD ) δ 7.35, 14.10, 85.52, 98.39, 121.15, 122.26,
3
3
1
1
23.90, 124.48, 126.07, 128.23, 128.93, 129.46, 129.75, 130.41, 141.17,
42.37, 143.17, 144.57, 145.21, 146.14, 147.98, 149.97, 182.04. 31
P
7
195
dx.doi.org/10.1021/ic500290m | Inorg. Chem. 2014, 53, 7188−7196

Inorganic Chemistry
Article
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