Phosphorescent Thiazol-2-ylidene Platinum(II) Complexes with β-Ketoiminates: Single Isomer Formation by Ligand Architecture

Article abstract of DOI:10.1021/acs.organomet.6b00710

We present the synthesis and photophysical properties of six novel N-phenyl-1,3-thiazol-2-ylidene platinum(II) complexes with sterically demanding N-aryl-β-ketoiminate ligands. Diverse aryl substituents at the coordinating nitrogen atom (phenyl, mesityl,

Full text of DOI:10.1021/acs.organomet.6b00710

Article
pubs.acs.org/Organometallics
Phosphorescent Thiazol-2-ylidene Platinum(II) Complexes with
β‑Ketoiminates: Single Isomer Formation by Ligand Architecture
Hendrik Leopold and Thomas Strassner*
̈
Physikalische Organische Chemie, Technische Universitat Dresden, Bergstrasse 66, 01069 Dresden, Germany
*
S Supporting Information
ABSTRACT: We present the synthesis and photophysical
properties of six novel N-phenyl-1,3-thiazol-2-ylidene
platinum(II) complexes with sterically demanding N-aryl-β-
ketoiminate ligands. Diverse aryl substituents at the coordinat-
ing nitrogen atom (phenyl, mesityl, 2,6-diisopropylphenyl, 4-
cyanophenyl, 1-naphthyl, and 2,4-difluorophenyl) of the N-
aryl-(3Z)-4-amino-3-penten-2-ones exclusively yielded the SP-
∧
4
-3 coordinated C C* cyclometalated platinum(II) complexes
as single isomers as a consequence of the low steric demand of
∧
the C C* cyclometalating thiazole ligand and the bulkiness of
the β-ketoiminate ligands. The formation of this isomer was
confirmed by 1 Pt NMR and extensive 2D NMR experiments, two solid-state structures, and the results of DFT calculations. As
95
a proof of principle, two complexes with the sterically less demanding β-ketoiminate ligands (3Z)-4-amino-3-penten-2-onato and
(
2Z)-3-amino-1-phenyl-2-buten-1-onato were synthesized and isolated as an isomeric mixture.
INTRODUCTION
In addition, coordination compounds of platinum(II) with
similar β-ketoiminate structures have been presented with
■
Photoluminescent, organometallic compounds attract great
interest due to their interesting properties and numerous
14
interesting photophysical properties, but problems of isomer
formation and subsequent separation, due to the unsymmetrical
1
applications. In particular, transition metal complexes are used
15
nature of the β-ketoiminate ligand, were reported.
as high-performance materials for the fabrication of photo-
electronic devices such as dye-sensitized solar cells and organic
2
Recently, cyclometalated 1,3-thiazol-2-ylidene-based NHC
3
platinum(II) complexes with acetylacetonate ligands were
light-emitting diodes (OLEDs)4, next to being valuable
16
reported as phosphorescent emitters. The 1,3-thiazole motif
provides variable electronic effects and a different steric
environment compared to typical imidazole- and triazole-
synthetic tools in photocatalysis. The use of diverse ligand
architectures to modify different electronic effects onto the
metal atom and to establish defined steric environments has
emerged into a widespread research area in photophysics and
∧
based heterocycles and their complexes. By using the C C*
5
photochemistry.
cyclometalating N-aryl-1,3-thiazol-2-ylidene motif we wanted to
take advantage of the reduced steric demand to exclusively yield
single isomers from the complex synthesis even with unsym-
metrical β-ketoiminate ligands. We therefore studied the steric
effect of bulky groups attached to the nitrogen atom of the β-
ketomine ligand on the complex formation and the photo-
physical properties. We herein present the synthesis of six novel
N-phenyl-1,3-thiazol-2-ylidene platinum(II) complexes with
sterically demanding N-aryl-(3Z)-4-amino-3-penten-2-onato
ligands. In addition, the corresponding complexes based on
the (3Z)-4-amino-3-penten-2-one motif, with no further steric
demand at the nitrogen atom, were synthesized. Two solid-state
structures unambiguously confirm the formation of the
proposed isomers. Density functional theory (DFT) calcu-
lations using different functionals (B3LYP, BP86, B97D) agree
with the experimental results.
With the development of OLEDs based on phosphorescent
transition metal complexes, the need to achieve defined
excited states is met by using specifically designed ligands. In
particular, cyclometalated complexes with phenylpyridines or
arylimidazole-based N-heterocyclic carbenes (NHCs) show an
excellent photophysical performance. Among the auxiliary
ligands used in combination with bidentate C N or C C*
cyclometalating ligands, the monoanionic, bidentate acetyl-
acetonate (acac) and its derivatives were investigated in several
studies, and different highly phosphorescent emitters with O O
coordinating ligands have been presented.
Compared to typical acac ligand systems, β-ketoimines
acnac) have the advantage of applying electronic and steric
effects via the (substituted) nitrogen atom while still keeping
the monoanionic, bidentate ligand structure. N-Aryl-β-ketoimi-
nates have previously been used as coordination compounds for
different photoluminescent complexes with gallium (Scheme 1,
I) and aluminum (Scheme 1, II) and in phosphorescent
iridium(III) emitters (Scheme 1, III and IV).
6
7
8
9
∧
∧
∧
5
d,e,10
(
1
1
12
Received: September 16, 2016
13
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.organomet.6b00710
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Article
Scheme 1. Overview of Different Photoluminescent β-Ketoiminate-Based Metal Complexes
RESULTS AND DISCUSSION
Synthesis and Characterization. The N-phenyl-4,5-
dimethyl-1,3-thiazol-2-ylidene motif was chosen as the C C*
cyclometalating NHC ligand in the platinum(II) complex
synthesis because of the lower steric demand next to the sulfur
atom in comparison to imidazole or triazole compounds (see
Scheme 2). NHC precursor 1 was prepared starting from the
All complexes have been characterized by standard
techniques including 19F (for 13) and Pt NMR, as well as
extensive 2D NMR investigations to confirm the identity of the
expected preferred isomers (see Figure 1 for the structures of
the synthesized complexes).
■
195
∧
a
Scheme 2. Synthesis of Complexes 8−13
a
Conditions: (i) Ag O, rt to 50 °C, DMF; (ii) Pt(COD)Cl , rt to 115
2
2
t
°C, DMF; (iii) KO Bu, N-arylketoimine 2−7, rt to 100 °C, DMF.
Figure 1. Synthesized complexes 8−13.
aniline, by synthesis of the N-phenyl-1,3-thiazol-2-thione and
the oxidation to the corresponding 1,3-thiazolium salt followed
by a salt metathesis.
16
1H and 195Pt NMR spectra of compounds 8−13 reveal the
exclusive formation of only a single isomer. All complexes show
a single 1 Pt NMR resonance with a chemical shift of −3394
(8) to −3417 (11) ppm, which is in the typical range of similar
The synthesis of the sterically and electronically different N-
aryl-substituted β-ketoimine compounds 2−7 was accom-
plished by reaction of Hacac with the corresponding aniline
derivatives using a Dean−Stark trap for the azeotropic removal
95
∧
10b,f
C C* cyclometalated platinum(II) complexes.
We meas-
1
7
of water.
The synthesis of the platinum(II) complexes followed a
ured additional 2D NMR spectra for 8−13 and focused on the
NOESY experiments. As an example we will discuss the
determination of the isolated SP-4-3 isomer for complex 8
(Figure 2, for additional NMR spectra see the Supporting
Information, Figures S1−S31).
The most defining interaction in the NOESY spectrum
consists of a coupling of the auxiliary ligand’s methyl group at
2.14 ppm with the characteristic, most deshielded proton of the
cyclometalating aryl system at 8.27 ppm (Figure 2, red). In
addition, a coupling of said methyl group at 2.14 ppm with the
single proton of the β-ketoiminate ligand at 5.18 ppm is
observed (Figure 2, orange). In agreement with this orientation
of the β-ketoiminate ligand, we see the coupling of the second
β-ketoiminate’s methyl group at 1.63 ppm, not only with the
single proton of the β-ketoiminate ligand at 5.18 ppm (Figure
2, green) but also with the nitrogen-bound phenyl ring of the β-
ketoiminate at 7.13 ppm (Figure 2, blue).
10c,16
modified literature procedure.
The N-phenyl-1,3-thiazo-
lium salt 1 was reacted with silver(I) oxide (Ag O) in dry
2
dimethylformamide (DMF) to in situ generate the silver(I)-
carbene complex, which was transmetalated to dichloro(1,5-
cyclooctadiene)platinum(II) (Pt(COD)Cl ). Cyclometalation
2
at elevated temperatures and reaction with the β-ketoimine
auxiliary ligands under basic conditions using potassium tert-
t
butanolate (KO Bu) as the base (Scheme 2) led to complexes
8−13.
We were pleased to find that the use of the sterically
demanding N-aryl-substituted β-ketoimine ligands 2−7 led to
the exclusive formation of single isomers of 8−13. In detail, the
SP-4-3 coordinated isomers with the N-aryl substituents of the
β-ketoiminate ligand oriented to the 1,3-thiazole moiety were
isolated (see the characterization vide infra for further details).
Overall, complexes 8−13 were obtained in analytically pure
form, after further washing with isohexanes and diethyl ether, in
yields of 18% to 40%.
With this, we can conclude that the synthesized and isolated
isomer is indeed the SP-4-3 coordinated platinum(II) complex
8. The formation of only this isomer is a result of the steric
B
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Figure 2. NOESY spectrum of compound 8 with highlighted CH −Haryl interactions.
3
demand of the nitrogen-bound aryl ring of the β-ketoiminate
ligand in combination with the steric demand of the thiazole
heterocycle. For complexes 9−13 the same characteristic
NOESY couplings are observed (see Supporting Information,
Figures S26−S31), supporting the preferred formation of the
SP-4-3 isomers for this new class of complexes.
mol, which is in good agreement with the experimental results
from the NMR studies.
Additionally, we were able to obtain single crystals of
complexes 8 and 12 (Figures 3 and 4). Both structures
unambiguously confirm the expected orientation of the β-
ketoiminate ligand. Selected bond lengths and angles are given
in the figure legends; for further information refer to the
Supporting Information Tables S7 and S8 and Figure S35. The
solid-state structures of complexes 8 and 12 show a square-
planar coordination environment for the platinum(II) center.
The C1−Pt1−C7 angle in the five-membered ring is smaller at
79.0(3)° for 8 and 78.9(5)° for 12 compared to the nearly
rectangular N1−Pt1−O1 angle of 88.9(2)° for 8 and 89.3(4)°
for 12 in the six-membered ring. The bond length between the
platinum atom and the electronically different coordinating
atoms follow the expectation: the Pt1−N2 distances are the
longest platinum contacts (2.112(5) Å for 8 and 2.109(9) Å for
12), whereas those to the carbene carbon atom (Pt1−C1) are
the shortest (1.944(7) Å for 8 and 1.959(12) Å for 12).
We additionally calculated the ground-state geometries of
both isomers of complex 8 with DFT methods to investigate
the distances of defining hydrogen−hydrogen through-space
interactions in both isomers (see Supporting Information,
Figure S32). For the SP-4-3 coordinated isomer 8 short
distances and therefore possible interactions of the protons at
the β-ketoiminate methyl group with the proton adjacent to the
cyclometalating carbon atom are found. In addition, inter-
actions between the second methyl group and the protons at
the nitrogen-bound phenyl ring of the β-ketoiminate ligand are
observed. These results agree well with the observed couplings
from the NOESY experiment for compound 8 (Figure 2). The
corresponding signals can also be observed for complexes 9−
∧
13.
Compared to other solid-state structures of C C* cyclo-
We then chose to calculate the free energy differences of the
metalated complexes from the literature, the observed bond
lengths and angles in this study are in very good agreement
with previously reported data. Additionally, the N-bound aryl
systems of the β-ketoiminate ligand are almost orthogonally
oriented to the coordination plane, with 70.8(7)° for 8 and
83.0(1)° for 12, preventing molecular aggregation. In agree-
ment with the higher steric demand of the aryl substituents,
isomers with different functionals (BP86, B3LYP, B97D)
together with the 6-31G(d) basis set. For a summary of the
results and selected structural data see the Supporting
Information, Figures S33 and S34 and Tables S1−S6. For
complexes 8−13 the SP-4-3 coordinated isomers are generally
favored, with average energy differences of −1.9 to −2.3 kcal/
C
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Article
free energy difference that is >1.9 kcal/mol in favor of the SP-4-
3
isomers.
To test the hypothesis, we also synthesized the sterically less
demanding β-ketoimines (3Z)-4-amino-3-penten-2-one (14)
1
5,18
and (2Z)-3-amino-1-phenyl-2-buten-1-one (15)
tion of Hacac (for 14) or respectively of 1-phenyl-1,3-
by reac-
3
3,35
butandione (for 15) with ammonium carbamate.
Synthesis
and isolation of the complexes followed the same route as
described for complexes 8−13. As anticipated, both complexes
(
16 and 17) were isolated as a mixture of two isomers (see
Scheme 3 and the Experimental Section for further details).
a
Scheme 3. Synthesis of Complexes 16 and 17
Figure 3. ORTEP representation of complex 8. Thermal ellipsoids are
drawn at the 50% probability level. Selected bond lengths (Å), angles
(
1
deg), and dihedral angles (deg): C1−Pt1 1.944(7); C7−Pt1
.986(7); Pt1−N2 2.112(5); Pt1−O1 2.041(5); N2−C17 1.441(9);
C1−Pt1−C7 79.0(3); N1−Pt1−O1 88.9(2); C1−N1−C6−C7−
.3(8).
2
a
Conditions: (i) Ag O, rt to 50 °C, DMF; (ii) Pt(COD)Cl , rt to 115
2
2
t
°
C, DMF; (iii) KO Bu, ketoimine 14 or 15, rt to 100 °C, DMF.
Next to an additional second signal set in the H and 13C
1
NMR spectra, the isomeric mixture of compound 16 shows two
separate 1 Pt resonances at −3351 and −3375 ppm, which
reveals the formation of two isomers. Even the use of an
additional phenyl group at the C1 position of the β-ketoiminate
ligand, as in complex 17 with an (2Z)-3-amino-1-phenyl-2-
95
1
95
buten-1-onato ligand, leads to two signal sets and two Pt
NMR signals at −3322 and −3349 ppm. DFT calculations
show smaller free energy differences for the isomers, with the
SP-4-3 coordinated complex disfavored over its SP-4-4
coordinated isomer.
By using sterically demanding N-aryl-β-ketoiminates as
∧
ligands, the formation of isomerically pure C C* cyclo-
metalated complexes can be controlled, even with unsym-
metrical ligands.
Photophysical Properties. Frequently photophysical data
in the literature report the absorption and emission spectra of
mixtures when the isomers are difficult to separate. In our case
the synthesis and isolation of only one isomer of 8−13 allowed
for a detailed investigation of the photophysical properties of
this novel class of (SP-4-3)-1,3-thiazol-2-ylidene platinum(II)
complexes with N-aryl-substituted β-ketoiminate auxiliary
ligands. We first recorded the absorption spectra in diluted
dichloromethane (DCM) solutions, which are shown in Figure
5.
Figure 4. ORTEP representation of complex 12. Thermal ellipsoids
are drawn at the 50% probability level. Selected bond lengths (Å),
angles (deg), and dihedral angles (deg): C1−Pt1 1.959(12); C7−Pt1
1
1
.991(12); Pt1−N2 2.109(9); Pt1−O1 2.033(10); N2−C17
.433(16); C1−Pt1−C7 78.9(5); N1−Pt1−O1 89.3(4); C1−N1−
C6−C7 1.9(14).
large intermolecular Pt···Pt-distances of 7.895(2) Å for 8 and
7
.833(2) Å for 12 (above the sum of their van der Waals radii)
For complexes 8−13 strong absorptions in the high-energy
are observed, indicating no Pt···Pt interaction in the solid state.
In summary, the NOESY spectra and the calculated
structures support the formation of the SP-4-3 isomers (8−
region below 275 nm can be observed, which are typically
∧
attributed to π−π* transitions for this class of C C*
10g
cyclometalated platinum(II) complexes.
Small maxima at
1
3) over the SP-4-4 isomers. This fact was unambiguously
about 340 nm together with stronger absorptions at about 370
proven by the solid-state structures of complexes 8 and 12. The
nm are found for all complexes. These absorptions are referred
1
formation of the SP-4-3 isomers can be explained by the low
to as metal-to-ligand charge transfer ( MLCT) states in the
∧
10g
steric demand of the 1,3-thiazole moiety of the C C*
literature.
Interestingly, despite the electronically and
cyclometalating ligand and the high steric demand of the
sterically diverse substituents present at the coordinating
nitrogen atom of the platinum(II) environment, almost no
change in their absorption behavior is observed.
∧
N O coordinating β-ketoiminate ligand. These findings can
also be confirmed by DFT calculations, which show an average
D
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the different β-ketoiminate ligands (for the individual spectra of
compounds 8−13 refer to the Supporting Information, Figures
S36−S41).
The photoluminescence data for complexes 8−13 are
summarized in Table 1 and reveal quantum yields (QY) from
7
% (8) up to 26% (10) with decay lifetimes between 22.5 μs
(
10) and 71.9 μs (8). The decay lifetime of complex 12 could
not be determined because of the detection limit of the
instrumental setup (τ > 350 μs). The complex with the 2,6-
0
diisopropylphenyl-substituted β-ketoimine ligand 10 shows the
highest quantum yield. The lowest quantum yield is observed
for the unsubstituted phenyl ring (8), while ortho-substituents
(
9, methyl; 10, isopropyl), which due to steric requirements
reduce the conjugation between the plane of the acnac system
and the substituent, lead to a higher quantum yield. Electron-
withdrawing substituents (11, cyano; 13, fluoro) also improve
the quantum yields (11, 19%; 13, 23%) and are beneficial for
shorter decay lifetimes.
For photophysical data for the isomeric mixtures of
complexes 16 and 17 refer to the Supporting Information,
Figures S42 and S43 and Table S9.
Figure 5. Absorption spectra of complexes 8−13 at room temperature
−4
−1
(
10 mol L in DCM).
In addition, we measured the emission spectra of amorphous
2
wt % emitter films of the corresponding complexes 8−13 in
poly(methyl methacrylate) (PMMA) at room temperature
Figure 6). All complexes show broad, unstructured emission
(
To further investigate the emission process, we calculated the
Kohn−Sham orbitals of the singlet-state geometries and spin
densities of the triplet-state geometries using DFT methods
(
see Supporting Information, Figure S44). All calculated triplet-
state geometries show strong distortions of the β-ketoimine
auxiliary ligand at the platinum(II) complexes. The relatively
low quantum yields of the complexes can therefore be
attributed to thermal quenching effects that result from
15
geometrical changes in the excited states.
CONCLUSIONS
We present the synthesis of the first bidentate C C*
cyclometalated platinum(II) complexes based on 1,3-thiazol-
■
∧
2
-ylidene ligands with unsymmetrical N-aryl-functionalized β-
ketoiminate ligands. All six complexes were exclusively obtained
as the SP-4-3 coordinated isomers due to the high steric
demand of the N-aryl-β-ketoiminate ligand and the use of N-
aryl-1,3-thiazol-2-ylidenes as the C C* cyclometalating ligands.
2
∧
Figure 6. Emission spectra of complexes 8−13 at room temperature
2 wt % in PMMA).
(
D NOESY spectra show long-range couplings between the
methyl group proton of the β-ketoiminate and the proton of
the cyclometalating aryl system. The N-aryl moiety of the β-
ketoiminate is oriented to the 1,3-thiazole heterocycle of the
NHC ligand, which was additionally proven by two solid-state
structures. For comparison, systems with no steric demand at
the coordinating nitrogen atom were synthesized, which as
expected yielded only an isomeric mixture. Their photophysical
properties were measured and revealed bluish-green phosphor-
escence with emission maxima of about 500 nm at room
temperature in 2 wt % PMMA films. DFT calculations support
the formation of the isolated SP-4-3 isomers.
bands with a stable maximum emission wavelength of about
00 nm (see Table 1). The use of different aryl systems at the
coordinating nitrogen atom does not change the band form or
the maximum emission wavelength, showing an interesting
dominant electronic effect of the 1,3-thiazole NHC ligand over
5
Table 1. Photoluminescence Data (2 wt % in PMMA, Room
Temperature) of Complexes 8−13
3
[103
λexc
no. [nm]
λem
[nm]
ϕ
[%]
τo
[μs]
k [10
k
r
s
nr
a
b
c
d
e
−1
f
s−1
g
CIE x;y
]
]
8
9
1
1
1
1
370
370
370
370
370
370
0.24;0.45
0.24;0.47
0.25;0.49
0.26;0.50
0.25;0.47
0.26;0.50
503
506
509
507
504
509
7
23
26
19
14
23
71.9
25.3
22.5
29.2
13.9
39.6
44.4
34.2
4681.2
4477.2
4334.8
4494.9
EXPERIMENTAL SECTION
■
General Experimental Procedures. All syntheses of the
platinum(II) complexes were performed under an argon atmosphere
and the exclusion of light, using flame-dried Schlenk tubes. Solvents of
at least 99.0% purity were used in this study. DMF was dried using
standard techniques and stored under an argon atmosphere over
0
1
2
3
h
h
h
−
23.1
−
43.4
−
4084.0
molecular sieves (3 Å). Dichloro(1,5-cyclooctadiene)platinum(II)
a
b
19
Excitation wavelength. CIE coordinates at room temperature.
(Pt(COD)Cl ) was prepared according to a modified literature
2
c
d
10c
Maximum emission wavelength. Quantum yield at λexc; N2
procedure. Compound 1 was synthesized according to a previously
e
16
atmosphere. Decay lifetimes (excited by laser pulses (360 nm, 20
kHz)) given as τ = τ /ϕ. k = ϕ/τ . k = (1 − ϕ)/τ . Decay lifetime
above detection limit.
described literature procedure. Compounds 4-(phenylamino)pent-3-
f
g
h
17a
en-2-one (2),
(3),
4-(2,4,6-trimethylphenylamino)pent-3-en-2-one
o
v
r
v
nr
v
1
7b
17b
and 4-(2,6-diisopropylphenylamino)pent-3-en-2-one (4)
E
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were prepared according to the literature procedures. Compounds 4-
refined with anisotropic displacement parameters. Full-matrix least-
2
2 2
(
N-(4-cyanophenyl)amino)pent-3-en-2-one (5), 4-(N-(naphthyl)-
squares refinements were carried out by minimizing ∑w(Fo − F )
c
amino)pent-3-en-2-one (6), and 4-(N-(2,4-difluorphenyl)amino)-
with the SHELXL-97 weighting scheme. Neutral-atom scattering
factors for all atoms and anomalous dispersion corrections for the non-
hydrogen atoms were taken from the International Tables for
pent-3-en-2-one (7) were prepared following a modified literature
1
7b
procedure as described below.
one (14)
Compounds 4-aminopent-3-en-2-
15,18
15,18
31
and 3-amino-1-phenylbut-2-en-1-one (15)
were
Crystallography. All calculations were performed with the programs
3
2
33
34
29b
29a
prepared according to the literature procedures. Chemicals were
obtained from common suppliers and used without further
COLLECT,
DIRAX,
EVALCCD,
SIR92,
SIR97,
36
2
8
35
SADABS, the SHELXL-97 package, and PLATON. Images of
the solid-state structures were generated with ORTEP-3 and
1
13
19
195
37
purification. H, C, F, and Pt NMR spectra were recorded on
1
13
38
Bruker NMR spectrometers. H and C NMR spectra were referenced
Mercury.
1
13
internally by using the resonances of the solvent ( H, 7.26 ppm; C,
Synthesis of Ligands 5−7. 4-(N-(4-Cyanophenyl)amino)pent-3-
en-2-one (5). In a 50 mL round-bottom flask with a Dean−Stark
apparatus 5.01 g (50 mmol) of acetylacetone and 6.63 g (55 mmol, 1.1
equiv) of 4-aminobenzonitrile in 30 mL of benzene are combined,
before 15 drops of concentrated hydrochloric acid (37 wt %) are
added. The reaction mixture is stirred at 110 °C for 24 h. The resulting
black suspension is filtered, and the remaining solid is washed with 10
mL of isohexanes. The filtrate is collected and treated with 100 mL of
diethyl ether. After 4 h at room temperature a yellow solid precipitates.
The solid is filtered, washed with 50 mL of diethyl ether, and dried
7
7.0 ppm for CDCl3). 19F NMR spectra are referenced externally
195
against trifluoromethylbenzene as the standard signal. Pt NMR
spectra were referenced externally by using potassium
2
−
tetrachloroplatinate(II) in D O (−1617.2 ppm (PtCl ), −2654.1
2
4
ppm (PtCl )). Shifts are given in ppm; coupling constants J in Hz.
2
Mass spectra of ligands 5−7 were recorded on an Agilent 6890N GC
coupled with a 5973N MSD system using electron ionization (EI) as
the ionization method. The reported masses are assigned to the
matching fragments and referenced to the basis peak. Electrospray
ionization mass spectra of compounds 8−13, 16, and 17 were
measured on a Bruker Esquire MS with ion trap detector. Elemental
analyses were performed on a Hekatech elemental analyzer by the
microanalytical laboratory of our institute. Uncorrected melting points
have been determined using a Wagner and Munz Poly Therm A
system. Photoluminescence measurements were performed in thin
PMMA films doped with 2 wt % emitter. The emitter films were
prepared by doctor blading a solution of emitter in a 10 wt % PMMA
solution in dichloromethane on a quartz substrate with a 60 μm doctor
blade. The film was dried, and the emission was measured under
nitrogen. Excitation was conducted at wavelengths of 370 nm (Xe
lamp with a monochromator), and the emission was detected with a
calibrated quantum yield detection system (Hamamatsu, model
C9920-02). The uncertainty of the quantum yield is ±2% for
quantum yields of >10%. The phosphorescence decay was measured
with an Edinburgh Instruments Mini-τ by excitation with pulses of an
EPLED (360 nm, 20 kHz) and time-resolved photon counting.
Absorption spectra were measured on a PerkinElmer Lambda 25 UV−
VIS spectrometer.
1
under high vacuum (3.71 g, 37.0%). Mp: 94−95 °C. H NMR
(CDCl , 25 °C, 300 MHz, tautomer A): δ 12.67 (s, 1H, NH), 7.59
3
(dd, J = 8.3 Hz, 2H, CHarom), 7.14 (d, J = 8.4 Hz, 2H, CHarom), 5.27 (s,
1
1H, CHacnac), 2.11 (2 s, 6H, CH ) ppm. H NMR (CDCl , 25 °C, 300
3
3
MHz, tautomer B): δ 15.45 (s, 1H, OH), 7.39 (dd, J = 8.7, 1.1 Hz, 2H,
CHarom), 6.63 (d, J = 8.7 Hz, 2H, CHarom), 5.48 (s, 1H, CHacnac), 2.02
(2 s, 6H, CH1
based on the H NMR integrations for the NH-proton resonance at 12.67
ppm and the OH-proton resonance at 15.45 ppm. 13C NMR (CDCl
, 25
°C, 75 MHz, tautomeric mixture): δ 202.0 (CO/CN), 197.5 (CO/
CN), 191.2 (CO/CN), 157.5 (C ), 150.4 (C), 143.3 (C ), 133.7
(CHarom), 133.2 (CHarom), 122.8 (CHarom), 120.1 (C ), 118.6 (C ),
114.4 (CHarom), 107.3 (C ), 100.4 (CHarom), 100.4 (CHarom), 100.1
(C ), 58.5 (CH ), 30.8 (CH ), 29.5 (CH ), 24.8 (CH ), 20.3 (CH
ppm. GC-MS (EI, m/z, fragment, %): 200 (M , 32), 185 (M − Me,
100). Anal. Calcd for C12 O: C, 71.98; H, 6.04; N, 13.99. Found:
C, 72.35; H, 6.25; N, 14.04.
) ppm. The tautomeric ratio of 20:1 (A:B) was determined
3
3
i
i
i
i
i
i
)
3
i
2
3
3
3
+
+
H N
12 2
4-(N-Naphthylamino)pent-3-en-2-one (6). In a 50 mL round-
bottom flask with a Dean−Stark apparatus 2.50 g (25 mmol) of
acetylacetone and 3.53 g (28 mmol, 1.1 equiv) of 1-naphthylamine in
30 mL of toluene are combined, before 15 drops of concentrated
hydrochloric acid (37 wt %) are added. The reaction mixture is stirred
at 130 °C for 24 h. The resulting black solid is filtered off, and the
filtrate is treated with 100 mL of diethyl ether. Again a dark solid is
formed and filtered off to remove side products. The remaining diethyl
ether−benzene mixture is evaporated using a rotary evaporator. The
product is then isolated via flash column chromatography using an
20
Computational Details. The Gaussian09 package was used to
perform all quantum chemical calculations employing the density
2
1
22
functional hybrid model B3LYP, gradient-corrected BP86, and
23
dispersion-corrected B97D. All functionals were combined with a 6-
1G(d) basis set. In all calculations platinum was described with a
24
3
25
decontracted Hay-Wadt(n+1) ECP and basis set. All given structures
were verified as true minima by vibrational frequency analysis and the
absence of negative eigenvalues. By applying thermochemical analysis
approximate free energies could be obtained. Thermal corrections to
Gibbs free energy, as reported by Gaussian09, were taken into account
including zero-point effects, thermal enthalpy corrections, and entropy.
All presented energies, unless otherwise stated, are free energies at
standard conditions (T = 298 K, p = 1 atm) using unscaled
frequencies. Frontier molecular orbitals and spin densities were
ethyl acetate−isohexanes mixture (1:3) and obtained as a red-orange
1
oil (2.58 g, 22.9%). H NMR (CDCl
, 25 °C, 300 MHz): δ 12.75 (s,
3
1H, NH), 8.07−7.98 (m, 1H, CHarom), 7.91−7.83 (m, 1H, CHarom),
7.77 (d, J = 8.3 Hz, 1H, CH ), 7.58−7.49 (m, 2H, CH ), 7.48−
arom
arom
7.41 (m, 1H, CHarom), 7.28 (dd, J = 7.3 Hz, J = 0.7 Hz, 1H, CH ),
arom
1
3
5.31 (s, 1H, CHacnac), 2.18 (s, 3H, CH ), 1.88 (s, 3H, CH ) ppm.
C
3
3
26
visualized by GaussView. Calculated geometries were visualized with
NMR (CDCl , 25 °C, 75 MHz): δ 196.5 (CO/CN), 161.8 (C ), 134.8
3
i
27
CYLview.
(C ), 134.2 (C ), 130.0 (C ), 128.2 (CHarom), 126.9 (2C, CHarom), 126.5
i i i
X-ray Crystallography. Yellow single crystals of compound 8
were grown by slow evaporation of a saturated dichloromethane
solution. Slow infusion of a saturated dichloromethane solution of
complex 12 with diethyl ether yielded the corresponding yellow single
crystals.
(CHarom), 125.2 (CHarom), 123.4 (CHarom), 122.8 (CHarom), 97.4
(CHarom), 29.2 (CH ), 19.6 (CH ) ppm. GC-MS (EI, m/z, fragment,
3
3
+
+
%): 225 (M , 100), 210 (M − Me, 81). Anal. Calcd for C H NO:
C, 79.97; H, 6.71; N, 6.22. Found: C, 79.88; H, 6.76; N, 6.46.
1
5
15
4-(N-(2,4-Difluoroyphenyl)amino)pent-3-en-2-one (7). In a 50 mL
round-bottom flask with a Dean−Stark apparatus 2.50 g (25 mmol) of
acetylacetone and 3.55 g (28 mmol, 1.1 equiv) of 2,4-difluoroaniline in
30 mL of toluene are combined, before 15 drops of concentrated
hydrochloric acid (37 wt %) are added. The reaction mixture is stirred
at 130 °C for 24 h. The resulting black solid is filtered off, and the
filtrate is treated with 100 mL of diethyl ether. Again a dark solid is
formed and filtered off to remove side products. The remaining diethyl
ether−benzene mixture is evaporated using a rotary evaporator. The
product is then isolated via flash column chromatography using an
ethyl acetate−isohexanes mixture (1:3) and obtained as a light yellow
Preliminary examination and data collection were carried out on a
Nonius κ-CCD diffraction system (FR590) equipped with an Oxford
Cryosystem cooling system at the window of a fine-focus sealed tube
using graphite-monochromated Mo Kα radiation (λ = 0.71073 Å).
The reflections were merged and corrected for Lorentz, polarization,
2
8
and decay effects. Absorption correction was applied using SADABS.
2
9
The structures were solved by a combination of direct methods with
the aid of difference Fourier synthesis and were refined against all data
30
using SHELXL-97. Hydrogen atoms were assigned to ideal positions
using the SHELXL-97 riding model. All non-hydrogen atoms were
F
DOI: 10.1021/acs.organomet.6b00710
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
1
solid (1.77 g, 16.8%). Mp: 36−39 °C. H NMR (CDCl , 25 °C, 300
2.11 (s, 6H, CH3;mesityl), 2.00 (s, 3H, CH3;NHC), 1.47 (s, 3H, CH3;acnac)
3
MHz): δ 12.07 (s, 1H, NH), 7.21−7.08 (m, 1H, CH ), 6.96−6.76
m, 2H, CH ), 5.26 (s, 1H, CH ), 2.11 (s, 3H, CH ), 1.88 (d, J =
.6 Hz, 3H, CH ) ppm. C NMR (CDCl , 25 °C, 75 MHz,
ppm. 13C NMR (CDCl , 25 °C, 125 MHz): δ 179.2 (CO/CN), 175.9
arom
3
(
0
(CO/CN), 162.5 (NCS), 150.9 (C -Pt), 148.0 (C ), 136.6 (C ), 135.3
arom
acnac
3
i
i
i
13
(C ), 134.7 (C ), 131.6 (2C, CHarom), 130.3 (2C, CHarom), 125.2
3
3
i
i
tautomeric mixture): δ 196.9 (CO/CN), 191.2 (CO/CN), 160.8 (dd, J
248.8 Hz, J = 11.0 Hz, CF), 160.7 (C ), 157.1 (dd, J = 250.7 Hz, J =
(CHarom), 123.6 (C ), 123.1 (CHarom), 113.0 (CHarom), 100.4 (CHarom),
i
=
26.7 (CH ), 23.4 (CH ), 20.9 (CH ), 18.1 (2C, CH ), 14.7 (CH ),
i
3
3
3
3
3
195
1
1
1
3
2.4 Hz, CF), 128.5 (dd, J = 9.6 Hz, J = 1.8 Hz, CHarom), 123.0 (dd, J =
2.9 Hz, J = 4.0 Hz, C ), 116.9 (dd, J = 9.0 Hz, J = 4.7 Hz, CHarom),
11.3 (dd, J = 22.2 Hz, J = 4.0 Hz, CHarom), 110.8 (dd, J = 22.0 Hz, J =
.8 Hz, CHarom), 104.7 (dd, J = 26.2 Hz, J = 24.3 Hz, CHarom), 103.7
12.5 (CH ) ppm. Pt NMR (65 MHz, 25 °C, CDCl ): δ −3390 ppm.
3
3
+
+
MS (ESI , m/z, fragment): 600.3 (M + H) . Anal. Calcd for
i
C H N OPtS: C, 50.07; H, 4.71; N, 4.67; S, 5.35. Found: C, 49.76;
25
28
2
H, 4.69; N, 4.61; S, 5.13.
(
2
dd, J = 26.4 Hz, J = 22.7 Hz, CHarom), 100.4 (CHarom), 98.0 (CHarom),
[4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-(2,6-bis-
19
9.2 (CH ), 24.8 (CH ), 19.3 (CH ), 19.2 (CH ) ppm. F NMR
(methylethyl)phenyl)-4-aminopent-3-en-2-onato-κN,κO]platinum-
3 3 3 3
(
II) (10). According to the general procedure A 20 mL of dry DMF was
added to a mixture of 268 mg (0.8 mmol) of the N-phenyl-4,5-
dimethyl-1,3-thiazolium hexafluorophosphate salt 1 and 102 mg (0.44
(
−
CDCl , 25 °C, 75 MHz, tautomeric mixture): δ −131.26 (s, CF),
3
124.39 (s, CF), −117.7 (d, J = 6.4 Hz, CF), −112.1 (d, J = 6.7 Hz,
+ +
CF) ppm. GC-MS (EI, m/z, fragment, %): 211 (M , 44), 196 (M −
mmol, 0.55 equiv) of Ag O. Stepwise addition of 299 mg (0.8 mmol,
Me, 100). Anal. Calcd for C H F NO: C, 62.55; H, 5.25; N, 6.63.
2
11
11 2
1
(
.0 equiv) of Pt(COD)Cl , 415 mg (1.6 mmol, 2.0 equiv) of 4-(N-
Found: C, 62.44; H, 5.23; N, 6.66.
2
2,6-diisopropylphenyl)amino)pent-3-en-2-one (4), and 180 mg (1.6
Synthesis of Complexes 8−13, 16, and 17. General Procedure
t
A. Dry DMF is added to a mixture of the N-phenyl-4,5-dimethyl-1,3-
thiazolium hexafluorophosphate salt 1 and 0.55 equiv of Ag O in a dry
Schlenk tube. The resulting solution is stirred at room temperature for
2
1
temperature and 22 h at 115 °C, followed by addition of the described
equivalents of the corresponding N-aryliminopentan-2-one and the
base (KO Bu). Afterward the mixture is stirred at room temperature
for another 24 h and then heated to 100 °C for 6 h. All volatiles are
removed in vacuo, and the remaining solid is dispersed in 50 mL of
distilled water and filtered. The solid residue is dissolved in
dichloromethane, and the complex isolated by flash column
chromatography using pure dichloromethane as the eluent. Sub-
sequent washing with isohexanes and diethyl ether yielded the pure
complexes.
mmol, 2.0 equiv) of KO Bu while following the general procedure A
yielded complex 10 as a yellow powder (203 mg, 39.5%). Mp: >330
2
1
°C (dec). H NMR (CDCl
, 25 °C, 500 MHz): δ 8.36−8.20 (m, 1H,
3
h and for 22 h at 50 °C under the exclusion of light. After addition of
CHarom), 7.39 (d, J = 8.1 Hz, 1H, CHarom), 7.35−7.28 (m, 1H,
CHarom), 7.28−7.25 (partially omitted by solvent signal, m, 1H, CHarom),
7.24 (d, J = 1.0 Hz, 1H, CHarom), 7.16 (td, J = 7.4, 0.8 Hz, 1H,
CHarom), 7.05−7.00 (m, 1H, CHarom), 5.26 (s, 1H, CHarom), 3.31
equiv of Pt(COD)Cl stirring is continued for another 2 h at room
2
t
(hept, J = 6.8 Hz, 2H, CH(CH
CH3;acnac), 2.02 (s, 3H, CH3;NHC), 1.57 (s, 3H, CH3;acnac), 1.12 (d, J =
6.9 Hz, 6H, CH(CH ), 1.02 (d, J = 6.8 Hz, 6H, CH(CH ) ppm.
, 25 °C, 125 MHz): δ 180.4 (CO/CN), 175.7 (CO/
CN), 163.1 (NCS), 150.9 (C -Pt), 148.3 (C ), 141.3 (C ), 136.2 (C ),
) ), 2.60 (s, 3H, CH3;NHC), 2.19 (s, 3H,
3 2
)
)
3 2
3
2
13
C NMR (CDCl
3
i
i
i
i
134.0 (C ), 131.5 (CHarom), 126.5 (CHarom), 125.2 (2C, CHarom), 125.1
i
(CHarom), 123.5 (C ), 123.2 (CHarom), 113.0 (CHarom), 100.1 (CHarom),
i
27.3 (2C, CH), 26.7 (2C, CH ), 24.5 (2C, CH ), 23.9 (2C, CH ), 14.7
3
3
3
195
[
4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-phenyl-
(CH ), 12.6 (CH ) ppm. Pt NMR (65 MHz, 25 °C, CDCl ): δ
3 3 3
+ +
4
-aminopent-3-en-2-onato-κN,κO]platinum(II) (8). According to the
−3412 ppm. MS (ESI , m/z, fragment): 642.3 (M + H) . Anal. Calcd
general procedure A 20 mL of dry DMF is added to a mixture of 268
mg (0.8 mmol) of the N-phenyl-4,5-dimethyl-1,3-thiazolium hexa-
fluorophosphate salt 1 and 102 mg (0.44 mmol, 0.55 equiv) of Ag O.
Stepwise addition of 299 mg (0.8 mmol, 1.0 equiv) of Pt(COD)Cl2,
for C H N OPtS: C, 52.41; H, 5.34; N, 4.37; S, 5.00. Found: C,
28
34
2
52.43; H, 5.08; N, 4.35; S, 4.74.
2
[4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-(4-cya-
nophenyl)-4-aminopent-3-en-2-onato-κN,κO]platinum(II) (11). Ac-
cording to the general procedure A 20 mL of dry DMF was added to a
mixture of 268 mg (0.8 mmol) of the N-phenyl-4,5-dimethyl-1,3-
thiazolium hexafluorophosphate salt 1 and 102 mg (0.44 mmol, 0.55
2
80 mg (1.6 mmol, 2.0 equiv) of 4-(N-phenylamino)pent-3-en-2-one
t
(2), and 180 mg (1.6 mmol, 2.0 equiv) of KO Bu while following the
general procedure A yielded complex 8 as a yellow powder (100 mg,
2
8
1
2.3%). Mp: 257−260 °C. H NMR (CDCl , 25 °C, 500 MHz): δ
equiv) of Ag O. Stepwise addition of 299 mg (0.8 mmol, 1 equiv) of
3
2
.29−8.15 (m, 1H, CH ), 7.42−7.31 (m, 3H, CH ), 7.30−7.23
Pt(COD)Cl , 641 mg (3.2 mmol, 4.0 equiv) of 4-(N-(4-cyanophenyl)-
arom
arom
2
(partially omitted by solvent signal, m, 1H, CH ), 7.13 (td, J = 7.4 Hz,
amino)pent-3-en-2-one (5), and 359 mg (3.2 mmol, 4.0 equiv) of
arom
t
J = 0.9 Hz, 1H, CHarom), 7.10−7.03 (m, 2H, CH ), 7.03−6.98 (m,
KO Bu while following the general procedure A yielded complex 11 as
arom
1
1
H, CHarom), 5.18 (s, 1H, CHacnac), 2.58 (s, 3H, CH
), 2.14 (s, 3H,
a yellow powder (85 mg, 18.2%). Mp: 286−288 °C. H NMR (CDCl ,
3;NHC
3
CH3;acnac), 2.00 (s, 3H, CH3;NHC), 1.63 (s, 3H, CH3;acnac) ppm. 13
NMR (CDCl , 25 °C, 125 MHz): δ 179.4 (CN), 176.3 (CO), 162.7
C
25 °C, 500 MHz): δ 8.32−8.07 (m, 1H, CH ), 7.73 (d, J = 8.4 Hz,
arom
2H, CH ), 7.46−7.32 (m, 1H, CHarom), 7.23 (partially omitted by
3
arom
(
(
NCS), 153.5 (C -Pt), 150.7 (C ), 136.3 (C), 134.2 (C ), 131.8
CHarom), 129.6 (2C, CHarom), 126.0 (2C, CHarom), 125.7 (CHarom),
solvent signal, d, J = 8.5 Hz, 2H, CHarom), 7.15 (td, J = 7.4 Hz, J = 0.9
Hz, 1H, CHarom), 7.03 (td, J = 8.1 Hz, J = 1.5 Hz, 1H, CHarom), 5.22 (s,
i
i
i
i
1
25.1 (CHarom), 123.8 (C ), 123.2 (CHarom), 113.0 (CHarom), 100.5
1H, CHarom;acac), 2.61 (s, 3H, CH3;NHC), 2.16 (s, 3H, CH3;acnac), 2.06
i
195
13
(CHarom), 26.7 (CH ), 24.7 (CH ), 14.6 (CH ), 12.5 (CH ) ppm. Pt
(s, 3H, CH3;NHC), 1.63 (s, 3H, CH3;acnac) ppm. C NMR (CDCl , 25
3
3
3
3
3
+
NMR (65 MHz, 25 °C, CDCl ): δ −3394 ppm. MS (ESI , m/z,
fragment): 558.3 (M + H) . Anal. Calcd for C H N OPtS: C, 47.39;
°C, 125 MHz): δ 178.1 (CO/CN), 177.5 (CO/CN), 161.9 (NCS),
3
+
157.8 (CN), 150.3 (C -Pt), 136.8 (C ), 133.7 (2C, CHarom), 133.3
22
22
2
i
i
H, 3.98; N, 5.02; S, 5.75. Found: C, 47.06; H, 3.97; N, 4.96; S, 5.74.
4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-(2,4,6-
trimethylphenyl)-4-aminopent-3-en-2-onato-κN,κO]platinum(II)
9). According to the general procedure A 20 mL of dry DMF was
(C ), 131.7 (CH ), 127.4 (CH ), 125.3 (CH ), 123.7 (C ),
i arom arom arom i
[
123.5 (CHarom), 122.9 (C ), 118.8 (C ), 113.2 (CHarom), 109.3 (Ci),
i i
100.9 (CH ), 26.9 (CH ), 24.8 (CH ), 14.6 (CH ), 12.5 (CH )
arom
3
3
3
3
(
195
+
ppm. Pt NMR (65 MHz, 25 °C, CDCl ): δ −3417 ppm. MS (ESI ,
m/z, fragment): 583.2 (M + H) . Anal. Calcd for C H N OPtS: C,
3
added to a mixture of 268 mg (0.8 mmol) of the N-phenyl-4,5-
+
23
21
3
dimethyl-1,3-thiazolium hexafluorophosphate salt 1 and 102 mg (0.44
mmol, 0.55 equiv) of Ag O. Stepwise addition of 299 mg (0.8 mmol, 1
equiv) of Pt(COD)Cl , 348 mg (1.6 mmol, 2 equiv) of 4-(N-(2,4,6-
trimethylphenyl)amino)pent-3-en-2-one (3), and 180 mg (1.6 mmol,
4
7.42; H, 3.63; N, 7.21; S, 5.50. Found: C, 47.13; H, 3.33; N, 7.03; S,
2
5.50.
2
[4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-(4-
naphthylphenyl)-4-aminopent-3-en-2-onato-κN,κO]platinum(II)
(12). According to the general procedure A 20 mL of dry DMF was
added to a mixture of 268 mg (0.8 mmol) of the N-phenyl-4,5-
dimethyl-1,3-thiazolium hexafluorophosphate salt 1 and 102 mg (0.44
t
2
equiv) of KO Bu (1.6 mmol, 2.0 equiv) while following the general
procedure A yielded complex 9 as a yellow powder (159 mg, 33.1%).
Mp: >318 °C (dec). H NMR (CDCl , 25 °C, 500 MHz): δ 8.35−
8
1
3
.18 (m, 1H, CH ), 7.36 (d, J = 8.1 Hz, 1H, CH ), 7.14 (t, J = 7.4
mmol, 0.55 equiv) of Ag O. Stepwise addition of 299 mg (0.8 mmol, 1
arom
arom
2
Hz, 1H, CHarom), 7.05−6.96 (m, 3H, CHarom), 5.22 (s, 1H, CHarom),
equiv) of Pt(COD)Cl , 721 mg (3.2 mmol, 4 equiv) of 4-(N-
(naphthyl)amino)pent-3-en-2-one (6), and 359 mg (3.2 mmol, 4.0
2
2
.58 (s, 3H, CH3;NHC), 2.41 (s, 3H, CH3;mesityl), 2.15 (s, 3H, CH3;acnac),
G
DOI: 10.1021/acs.organomet.6b00710
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
t
equiv) of KO Bu while following the general procedure A yielded
NMR (isomeric mixture, 65 MHz, 25 °C, CDCl ): δ −3351, −3375
3
+
+
complex 12 as a yellow powder (93 mg, 19.1%). Mp: >325 °C (dec).
H NMR (CDCl , 25 °C, 500 MHz): δ 8.40−8.15 (m, 1H, CHarom),
.09 (d, J = 8.4 Hz, 1H, CHarom), 7.86 (dd, J = 13.5 Hz, J = 8.0 Hz, 2H,
CHarom), 7.53 (t, J = 7.8 Hz, 1H, CHarom), 7.45 (dd, J = 10.9 Hz, J =
.0 Hz, 1H, CHarom), 7.37 (ddd, J = 6.8 Hz, J = 4.9 Hz, J = 1.0 Hz, 1H,
CHarom), 7.30 (d, J = 8.1 Hz, 1H, CHarom), 7.20 (d, J = 7.2 Hz, 1H,
ppm. MS (ESI , m/z, fragment): 482.3 (M + H) . Anal. Calcd for
1
C H N OPtS: C, 39.91; H, 3.77; N, 5.82; S, 6.66. Found: C, 39.91;
3
16 18 2
8
H, 3.78; N, 5.80; S, 6.46.
[4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[3-amino-
1
-phenyl-but-2-en-1-onato-κN,κO]platinum(II) (17). According to
4
the general procedure A 20 mL of dry DMF was added to a mixture of
68 mg (0.8 mmol) of the N-phenyl-4,5-dimethyl-1,3-thiazolium
2
CHarom), 7.17−7.11 (m, 1H, CHarom), 6.99 (m, 1H, CHarom), 5.30 (s,
hexafluorophosphate salt 1 and 102 mg (0.44 mmol, 0.55 equiv) of
1
3
1
H, CHacnac), 2.48 (s, 3H, CH
), 2.22 (s, 3H, CH3;acnac), 1.82 (s,
3;NHC
H, CH3;NHC), 1.52 (s, 3H, CH3;acnac) ppm. 13C NMR (CDCl , 25 °C,
Ag O. Stepwise addition of 299 mg (0.8 mmol, 1.0 equiv) of
2
3
Pt(COD)Cl , 516 mg (3.2 mmol, 4 equiv) of 3-amino-1-phenylbut-2-
25 MHz): δ 179.1 (CO/CN), 176.9 (CO/CN), 163.7 (NCS), 150.7
(Ci-Pt), 149.7 (C ), 136.1 (C ), 135.1 (C ), 133.9 (C ), 131.7 (CHarom),
29.7 (C), 127.7 (CHarom), 126.5 (CHarom), 126.4 (CHarom), 126.2
CHarom), 126.0 (CHarom), 125.2 (CHarom), 123.5 (2C, CHarom), 123.2
CHarom), 122.2 (CHarom), 113.0 (CHarom), 100.6 (CHarom), 26.9
CH ), 24.3 (CH ), 14.5 (CH ), 12.3 (CH ) ppm. Pt NMR (65
MHz, 25 °C, CDCl ): δ −3397 ppm. MS (ESI , m/z, fragment): 608.3
M + H) . Anal. Calcd for C H N OPtS: C, 51.39; H, 3.98; N, 4.61;
2
t
en-1-one (15), and 359 mg (3.2 mmol, 4.0 equiv) of KO Bu while
i
i
i
i
following the general procedure A yielded complex 17 as a mixture of
1
i
two regioisomers as a yellow powder (124 mg, 28.4%). Mp: >317 °C
(
(
(
1
(
dec). H NMR (isomeric mixture, CDCl , 25 °C, 300 MHz): δ 8.28−
3
195
8.15 (m, 0.3H, CH ), 8.06−8.00 (m, 2.6H, CH ), 7.51−7.46 (m,
arom
arom
3
3
3
3
+
2H, CHarom), 7.44−7.38 (m, 4.2H, CH ), 7.11−7.01 (m, 2.6H,
arom
3
+
CHarom), 5.79 (d, J = 2.1 Hz, 1H, CH ), 5.76 (d, J = 2.2 Hz, 0.3H,
(
arom
26
24
2
CHarom), 2.70 (s, 3.9H, CH ), 2.30 (s, 3H, CH ), 2.26 (s, 0.9H, CH ),
S, 5.28. Found: C, 51.03; H, 3.90; N, 4.46; S, 5.07.
3
3
3
2
.20 (s, 0.9H, CH ) ppm. The isomeric ratio was determined to be 1:0.3
[
4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[N-(2,4-di-
3
1
after investigation of the H NMR integrals for the CHacnac-proton signals
fluorophenyl)-4-aminopent-3-en-2-onato-κN,κO]platinum(II) (13).
According to the general procedure A 20 mL of dry DMF was
added to a mixture of 268 mg (0.8 mmol) of the N-phenyl-4,5-
dimethyl-1,3-thiazolium hexafluorophosphate salt 1 and 102 mg (0.44
at 5.79 and 5.78 ppm. 13C NMR (isomeric mixture, CDCl , 25 °C, 75
3
MHz): δ 190.3 (CN), 172.4 (CO), 165.4 (NCS), 152.5 (C -Pt), 140.6
i
(
1
C ), 136.9 (C ), 130.9 (CHarom), 129.4 (CHarom), 128.2 (CHarom),
26.9 (CHarom), 125.2 (CHarom), 124.0 (C ), 122.9 (CHarom), 114.2
i
i
i
mmol, 0.55 equiv) of Ag O. Stepwise addition of 299 mg (0.8 mmol, 1
equiv) of Pt(COD)Cl , 676 mg (3.2 mmol, 4 equiv) of 4-(N-(2,4-
2
(
CHarom), 96.6 (CHarom), 29.0 (CH ), 14.4 (CH ), 12.8 (CH ) ppm.
3 3 3
2
195
Pt NMR (isomeric mixture, 65 MHz, 25 °C, CDCl ): δ −3322,
difluorphenyl)amino)pent-3-en-2-one (7), and 59 mg (3.2 mmol, 4
3
+
+
t
−
3349 ppm. MS (ESI , m/z, fragment): 544.3 (M + H) . Anal. Calcd
equiv) of KO Bu while following the general procedure A yielded
1
for C H N OPtS: C, 46.32; H, 3.71; N, 5.15; S, 5.90. Found: C,
complex 13 as a yellow powder (85 mg, 17.9%). Mp: 274−276 °C. H
21 20
2
4
6.37; H, 3.66; N, 5.17; S, 5.92.
NMR (CDCl , 25 °C, 500 MHz): δ 8.34−8.05 (m, 1H, CH ), 7.38
3
arom
(
d, J = 8.0 Hz, 1H, CH ), 7.14 (tt, J = 14.4 Hz, J = 7.2 Hz, 1H),
arom
7
CH
.10−6.83 (m, 4H, CHarom), 5.25 (s, 1H, CHacnac), 2.61 (s, 3H,
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge on the
ACS Publications website at DOI: 10.1021/acs.organo-
met.6b00710.
■
), 2.15 (s, 3H, CH3;acnac), 2.07 (s, 3H, CH3;NHC), 1.67 (s, 3H,
3;NHC
S
CH3;acnac) ppm. 13C NMR (CDCl , 25 °C, 125 MHz): δ 178.4 (CO/
3
CN), 178.0 (CO/CN), 164.3 (NCS), 161.2 (dd, J = 248.3 Hz, J = 10.8
Hz, C ), 155.8 (dd, J = 248.3 Hz, J = 10.9 Hz, C ), 150.6 (C -Pt), 137.3
i
i
i
(
dd, J = 13.3 Hz, J = 3.8 Hz, CHarom), 136.9 (C ), 133.8 (C ), 131.7
i
i
(
1
3
CHarom), 129.0 (dd, J = 10.9 Hz, J = 2.4 Hz, CHarom), 125.6 (CHarom),
List of abbreviations, 1D and detailed 2D NMR spectra,
photoluminescence data, crystallographic data, and
details of the quantum chemical calculations (PDF)
Crystallographic data (CIF)
23.5 (C ), 123.3 (CHarom), 113.2 (CHarom), 112.1 (dd, J = 21.8 Hz, J =
i
.8 Hz, CHarom) 105.1 (dd, J = 25.8 Hz, J = 24.4 Hz, CHarom) 100.9
19
(
CHarom), 26.9 (CH ), 24.1 (CH ), 14.6 (CH ), 12.5 (CH ) ppm. F
3 3 3 3
NMR (CDCl , 25 °C, 75 MHz): δ −118.1 (d, J = 6.1 Hz, CF), −114.3
(
3
195
Optimized xyz-coordinates data (XYZ)
d, J = 6.1 Hz, CF) ppm. Pt NMR (65 MHz, 25 °C, CDCl ): δ
3
+
+
−
3395 ppm. MS (ESI , m/z, fragment): 594.2 (M + H) . Anal. Calcd
for C H F N OPtS: C, 44.52; H, 3.37; N, 4.72; S, 5.40. Found: C,
AUTHOR INFORMATION
Corresponding Author
Fax: +49 351-463-39679. Tel: +49 351-463-38571. E-mail:
thomas.strassner@chemie.tu-dresden.de.
22
20
2
2
■
*
4
4.88; H, 3.33; N, 4.59; S, 5.31.
[
4,5-Dimethyl-3-phenyl-κC′-1,3-thiazol-2-ylidene-κC]-[4-amino-
pent-3-en-2-onato-κN,κO]platinum(II) (16). According to the general
procedure A 20 mL of dry DMF was added to a mixture of 268 mg
(
0.8 mmol) of the N-phenyl-4,5-dimethyl-1,3-thiazolium hexafluor-
ORCID
ophosphate salt 1 and 102 mg (0.44 mmol, 0.55 equiv) of Ag O.
Stepwise addition of 299 mg (0.8 mmol, 1.0 equiv) of Pt(COD)Cl2,
2
Thomas Strassner: 0000-0002-7648-457X
Notes
The authors declare no competing financial interest.
3
17 mg (3.2 mmol, 4 equiv) of 4-aminopent-3-en-2-one (14), and 359
t
mg (3.2 mmol, 4.0 equiv) of KO Bu while following the general
procedure A yielded complex 16 as a mixture of two regioisomers as a
1
green powder (141 mg, 36.6%). Mp: 252−254 °C. H NMR (isomeric
ACKNOWLEDGMENTS
■
mixture, CDCl , 25 °C, 300 MHz): δ 8.19−7.94 (m, 1H, CH ),
3
arom
We would like thank the ZIH for the generous allocation of
computation time at their high-performance computing facility
and the Graduiertenakademie Dresden for financial support.
7
.72−7.29 (m, 5.6H, CH ), 7.22−7.11 (m, 1H, CH ), 7.11−6.94
arom
arom
(
m, 1H, 3.4H, CH ), 5.07 (s, 2.2H, CH ), 2.68 (s, 6.6H, CH ),
arom acnac 3
2
3
.26 (s, 3H, CH ), 2.24 (s, 3H, CH ), 2.07 (s, 7.2H, CH ), 2.04 (s,
3 3 3
.6H, CH ), 2.01 (s, 3H, CH ) ppm. The isomeric ratio was determined
3
3
1
REFERENCES
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■
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DOI: 10.1021/acs.organomet.6b00710
Organometallics XXXX, XXX, XXX−XXX

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