Platinum complexes with the SC6F4H-4 ligand - Synthesis, structures and spectroscopy

Article abstract of DOI:10.1016/j.ica.2014.07.058

The reaction of HSC₆F₄H-4 and base with suitable platinum(II) chlorido precursor complexes leads to mononuclear complexes containing diimine ligands [(N^N)Pt(SC₆F₄H-4) ₂], or [(N^N)Pt(Me)(SC₆F₄H-4)] (N^N = 2,2′-bipyridine (bpy), dipyrido[3,2-a:2′,3′-c]phenazine (dppz) or 11-trifluoromethyl-dipyrido[3,2-a:2′,3′-c]phenazine (CF ₃dppz)), cycloocta-1,5-diene (COD) complexes [(COD)Pt(SC ₆F₄H-4)₂] or [(COD)Pt(R)(SC₆F ₄H-4)] (R = Me, Bn (benzyl) or C₆F₅), or phosphine complexes cis-[(PPh₃)₂Pt(SC₆F ₄H-4)₂], [(dppe)Pt(SC₆F₄H-4) ₂] (dppe = 1,2-bis(diphenylphosphino)ethane) and [(dppb)Pt(C ₆F₅)(SC₆F₄H-4)] (dppb = 1,4-bis(diphenylphosphino)butane). Reaction of cis-[(DMSO)₂PtCl ₂] lead to the labile cis- and trans-[(DMSO)₂Pt(SC ₆F₄H-4)₂] which rapidly lose DMSO to yield polymeric [Pt(SC₆F₄H-4)₂]_m. Reaction of HSC₆F₄H-4 and KOtBu with K₂PtCl₄ gave K₂[Pt(SC₆F₄H-4)₄]. The new compounds were analysed and characterised by single crystal XRD, ¹H, ¹⁹F and ¹⁹⁵Pt NMR and IR spectroscopy. Both single crystal XRD (in the solid) and NMR (in solution) reveal that the ligand strength of the thiolate ligand ^-SC₆F₄H-4 strongly depends on the further ligands in the complexes. The crystal structures exhibit various inter- and intra molecular π stacking interactions of the SC ₆F₄H-4 coligands. The absorption spectroscopy and electrochemistry of the diimine complexes [(N^N)Pt(SC₆F ₄H-4)₂] (N^N = bpy, dppz and CF₃dppz) have been investigated and reveal that the Pt complexes are superior to the recently reported Pd derivatives in view of their application in photoactive materials.

Full text of DOI:10.1016/j.ica.2014.07.058

Inorganica Chimica Acta 423 (2014) 152–162
Contents lists available at ScienceDirect
Inorganica Chimica Acta
journal homepage: www.elsevier.com/locate/ica
Platinum complexes with the SC6F4H-4 ligand – Synthesis, structures
and spectroscopy
a
Verena Lingen a,b, Anna Lüning a, Christian Strauß a, Ingo Pantenburg a, Glen B. Deacon b, , Gerd Meyer ,
⇑
Axel Klein a,
⇑
a Universität zu Köln, Department für Chemie, Institut für Anorganische Chemie, Greinstrasse 6, D-50939 Köln, Germany
b School of Chemistry, Monash University, PO Box 23, VIC 3800, Australia
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 11 July 2014
Received in revised form 23 July 2014
Accepted 29 July 2014
Available online 13 August 2014
The reaction of HSC6F4H-4 and base with suitable platinum(II) chlorido precursor complexes leads to
mononuclear complexes containing diimine ligands [(N^N)Pt(SC6F4H-4)2], or [(N^N)Pt(Me)(SC6F4H-4)]
(N^N = 2,20-bipyridine (bpy), dipyrido[3,2-a:20,30-c]phenazine (dppz) or 11-trifluoromethyl-dipyr-
ido[3,2-a:20,30-c]phenazine (CF3dppz)), cycloocta-1,5-diene (COD) complexes [(COD)Pt(SC6F4H-4)2] or
[(COD)Pt(R)(SC6F4H-4)] (R = Me, Bn (benzyl) or C6F5), or phosphine complexes cis-[(PPh3)2Pt(SC6F4H-
4)2], [(dppe)Pt(SC6F4H-4)2] (dppe = 1,2-bis(diphenylphosphino)ethane) and [(dppb)Pt(C6F5)(SC6F4H-4)]
(dppb = 1,4-bis(diphenylphosphino)butane). Reaction of cis-[(DMSO)2PtCl2] lead to the labile cis- and
trans-[(DMSO)2Pt(SC6F4H-4)2] which rapidly lose DMSO to yield polymeric [Pt(SC6F4H-4)2]m. Reaction
of HSC6F4H-4 and KOtBu with K2PtCl4 gave K2[Pt(SC6F4H-4)4]. The new compounds were analysed and
characterised by single crystal XRD, 1H, 19F and 195Pt NMR and IR spectroscopy. Both single crystal
XRD (in the solid) and NMR (in solution) reveal that the ligand strength of the thiolate ligand ꢀSC6F4H-
4 strongly depends on the further ligands in the complexes. The crystal structures exhibit various inter-
Keywords:
Platinum
Perfluoro thiophenolate ligands
XRD
195Pt NMR spectroscopy
Electrochemistry
and intra molecular
p stacking interactions of the SC6F4H-4 coligands. The absorption spectroscopy and
electrochemistry of the diimine complexes [(N^N)Pt(SC6F4H-4)2] (N^N = bpy, dppz and CF3dppz) have
been investigated and reveal that the Pt complexes are superior to the recently reported Pd derivatives
in view of their application in photoactive materials.
Ó 2014 Elsevier B.V. All rights reserved.
1. Introduction
complexes [(N^N)Pt(SR)2] (N^N = diimine, e.g. 2,20-bipyridine
(bpy); R = aryl) [12,14,16,17,19] charge (electron density) has been
Although perfluoroarylthiolato-(perfluorothiophenolato)-plati-
num complexes have been described [1–6] from as early as their
non-fluorinated counterparts, namely in the 1960s [7–11], the lat-
ter have found considerable application in luminescent materials
[12–19], some minor interest in catalysis [20,21], as single source
precursors in CVD [22] and as DNA intercalators [23,24], whereas
almost no applications have been reported for the perfluorinated
derivatives. A reasonable explanation for the use of non-fluori-
nated complexes over perfluorinated derivatives, is that the aryl-
thiolate ligands represent an efficient electron-donor component
in the charge-transfer photophysics of such complexes. Thus, in
the photo-excited states of the established platinum diimine
moved from both the thiolate coligand and Pt d orbitals to the dii-
mine
p
accepting ligand (mixed L(S)L0(N^N)CT/M(Pt)L(N^N)CT transi-
tions). The same is true for the related and even more important
diimine arenedithiolato platinum complexes [(N^N)Pt(S2R)]
(S2R = arenedithiolates, such as 1,2-benzenedithiolate or 4-toluene-
1,2-dithiolate) [12,25]. A closer look reveals that electron-donating
substituents on the ꢀSR ligand decrease the charge transfer energy,
while electron-withdrawing groups lead to higher CT energies
[12,13,26,27]. Furthermore, aryldithiolate complexes [(N^N)Pt(S2-
R)] generally exhibit lower CT energies than bis(arylthiolate) com-
plexes [(N^N)Pt(SR)2] [12,13]. Even superior in this respect are
corresponding ethene-dithiolate or ethane-dithiolate complexes
[12,13,25]. For all these reasons, diimine Pt complexes with perflu-
oroarylthiolate coligands have not been studied widely [27], nor
have they been used in luminescent materials. On the other hand,
as has been pointed out by Weinstein et al., the higher energy of
the excited state goes along with a longer lifetime, in line with
the energy gap law [12,27]. For other applications, the differences
⇑
Corresponding authors.
E-mail addresses: glen.deacon@monash.edu (G.B. Deacon), axel.klein@uni-koeln.
de (A. Klein).
URLs:
http://monash.edu/science/about/schools/chemistry/staff/deacon.html
(G.B. Deacon), http://www.klein.uni-koeln.de (A. Klein).
http://dx.doi.org/10.1016/j.ica.2014.07.058
0020-1693/Ó 2014 Elsevier B.V. All rights reserved.

V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
153
of perfluorinated complexes compared with non-fluorinated deriv-
atives are less clear. Generally the electron-withdrawing fluorine
substituents should stabilise these complexes compared with
those of the ꢀSPh ligand.
As expected from the soft character of arylthiolate ligands
[Pt(SR)] or [Pt(SR)2] moieties are very stable and thus frequently
used as building blocks in coordination chemistry [16,18,28]. For
perfluoroaryl (SRF) derivatives the combination with good to excel-
by-products may be a problem. Reaction (3) largely avoids this dis-
advantage but uses the toxic compounds Tl(SRF) [31,34], Pb(SRF)2
[6,29,33,35–37], and SnPh2(SRF)2 [30], which have to be prepared
in separate steps. For all these reasons the direct reaction (4), start-
ing from HSRF and chlorido precursor complexes is superior but
usually requires a stable complex scaffold [(chelate ligand)Pt] to
yield monomeric and stereochemically defined products [32].
Another advantage is that the necessary preparation of the precur-
sor complexes [(L)2PtCl2] is usually extremely simple, e.g. the reac-
tion of K2PtCl4 with many chelate ligands such as 2,20-bipyridine
(bpy) [40], 1,2-bis(diphenylphosphino)ethane (dppe) [41], or 1,5-
cyclooctadiene (COD) [42] proceeds smoothly with very high yields.
We became interested in the preparation of polyfluoroarylthio-
late complexes [(N^N)Pt(SC6F4H-4)2] with the S(C6F4H-4) thiolate
lent p-accepting ligands, such as phosphines [1–4,6,29–32], imines
[27,33,34], thioethers [35], and COD (COD = cycloocta-1,5-diene)
[36,37], is favourable, while complexes of weaker ligands as allyl
or amines have not been reported. Interestingly, the complexes
[(COD)Pt(SRF)2] (SRF = SC6F5, SC6F4H-4, SC6F4(CF3)-4, are quite sta-
ble [36,37] and thus may be used as precursor complex for further
platinum complexes, while no corresponding palladium complex
has been reported and allyl-, amine-, or thioether-palladium com-
plexes are also scarce [38].
For the synthesis of mononuclear complexes of both Pd and Pt
with arylthiolate ligands of the type [(L)2M(SR)2] (Scheme 1), a fre-
quently encountered problem is the formation of insoluble poly-
mers [M(SR)2]m [1–3] or oligonuclear complexes [7,31,35,38,39].
This tendency is slightly lower for perfluorinated ligands ꢀSRF com-
pared with non-fluorinated derivatives ꢀSR and slightly lower for
Pd compared with Pt. As a consequence, the first [Pt(SR)2] com-
plexes carrying non-fluorinated coligands ꢀSR were dimeric [7,9]
and mononuclear complexes were first prepared from suitable
mononuclear precursor complexes (e.g. azido complexes) [8], by
oxidative cis-addition of corresponding disulfides RSꢀSR [9], using
chelating phosphines [10], or very bulky thiolates [11]. In contrast
to this, mononuclear complexes containing perfluorinated arylthi-
olate ligands SRF and monodentate phosphine ligands were
reported early [3,4], and complexes of chelate ligands can be read-
ily prepared [4,6,26,27,29c,30,31a,31c,32–34,35a,36b,39c].
Several routes to mononuclear Pt perfluoroarylthiolate com-
plexes of the composition [(L)2Pt(SRF)2] have been described. They
can be divided into different reaction types (Scheme 1). The oldest
reported method (reaction 1 in Scheme 1) is the conceptually sim-
plest [2–4], but disadvantages lie in the use of the still not fully char-
acterised polymeric [Pt(SRF)2]m starting materials, which have to be
prepared from PtII salts and suitable thiolates M(SRF)n (M = main
group metal) (reaction 5) [1–3,5]. These polymers are almost insol-
uble, hence their use in synthesis of complexes requires prolonged
reaction times or harsh reaction conditions. Furthermore, often
product mixtures are obtained. In contrast to this, reaction (2) pro-
ceeds very smoothly and the products can be easily separated [3].
However, the method requires the preparation of the corresponding
tetraalkylammonium, sodium or potassium salts (A)2[Pt(SRF)4]
(A = Bu4N, Et4N, Na or K) (reactions 6a and 6b) [1–3] and results in
a loss of two equivalents of ꢀSRF. Here, the formation of oligomeric
and
a
-diimine ligands such as 2,20-bipyridine (bpy), or dipyr-
ido[3,2-a:20,30-c]phenazine (dppz) (Scheme 2) and explored the
reactions 3 and 4, starting from the corresponding dichlorido com-
plexes and KSC6F4H-4 or HSC6F4H-4 (in the presence of base). As
alternatives, we sought a ‘‘one-pot method’’ for the preparation of
these complexes from suitable simple Pt precursors such as K2PtCl4
or [(DMSO)2PtCl2] and replacement reactions of the previously
reported precursor complex [(COD)Pt(SC6F4H-4)2] [36] with N^N
ligands. In this contribution we report on the preparation of the dii-
mine complexes [(bpy)Pt(SC6F4H-4)2], [(bpy)Pt(Me)(SC6F4H-4)] and
[(dppz)Pt(SC6F5H-4)2] from their chlorido precursor complexes
(route 3). In the same way we also prepared the COD complexes,
[(COD)PtCl(SC6F4H-4)],
[(COD)Pt(Me)(SC6F4H-4)],
[(COD)Pt(B
n)(SC6F4H-4)] (Bn = benzyl) and some phosphine Pt complexes.
We were able to crystallise many of these compounds suitably for
X-ray crystallography. We also report the preparation and crystal
structure of K2[Pt(SC6F4H-4)4] prepared from K2PtCl4 and HSC6F4-
H-4. Furthermore, the absorption spectroscopy and electrochemis-
try of the diimine complexes [(N^N)Pt(SC6F4H-4)2] (N^N = bpy,
dppz or CF3dppz) were investigated and compared with correspond-
ing reported data for the related Pt complexes [(bpy)Pt(SC6F5)2],
[(bpy)Pt(SC6F4(CN)-4)2] and [(bpy)Pt(SC6H5)2] [26,27]. The use of
dppz (dipyrido[3,2-a:20,30-c]phenazine) and its 11-CF3 derivative
(CF3dppz) was motivatedby the intriguingproperties of dppz, which
combines the coordination properties of bpy with the excellent elec-
tron-accepting properties of phenazine (phz, Scheme 2) [43–45].
2. Experimental
2.1. General information
Commercially available reagents from Apollo or Alfa Aesar were
used without further purification. Acetone was dried over molecu-
lar sieves and distilled. All reactions and measurements involving
metal complexes were conducted under argon, using standard
Schlenk techniques. The solid products were air-stable. The ligands
dppz and CF3dppz [43], the potassium thiolate KSC6F4H-4 [46] and
the complexes [(COD)PtCl2] [42], [(COD)Pt(Me)Cl] [42], [(bpy)PtCl2]
[40], [(dppz)PtCl2] (as for the bpy derivative) [40], [(dppe)PtCl2]
[41], [(dppb)PtCl2] [41a], [(dppb)Pt(C6F5)Cl] [47], cis-[(PPh3)2PtCl2]
[48], and [(DMSO)2PtCl2] [49], were obtained according to literature
procedures.
(1)
1/m [Pt(SRF)2]m + 2 L
[(L)2Pt(SRF)2]
[(L)2Pt(SRF)2]
[(L)2Pt(SRF)2]
[(L)2Pt(SRF)2]
[(L)2Pt(SRF)2]
[Pt(SRF)2]m
(R4N)2[Pt(SRF)4]
+ 2 L
(2a)
+ 2 (R4N)SRF
+ 2 (M')SRF
+ 2/n MCln
+ 2 HCl
(M') [Pt(SR ) ]
+ 2 L
(2b)
(3)
(4)
2
F 4
2/n M(SRF)n
+ [(L)2PtCl2]
2 HSRF + [(L)2PtCl2]
PtX2
2.2. Instrumentation
(5)
+ 2/n M(SRF)n
+ 2/n MXn
The NMR spectra were recorded on a Bruker Avance II 300 MHz
(1H: 300.13 MHz, 19F: 282.23 MHz) using a triple resonance 1H, 19F,
BB inverse probehead. The broad band coil was tuned to the plat-
inum frequency and the detection coil to the proton frequency,
+ 2 KCl + 4 HCl (6a)
4 HSRF + K2PtCl4 + 2 (R4N)Cl
4 HSRF + M'2PtCl4+ 4 M'OH
(R4N)2[Pt(SRF)4]
(M')2[Pt(SRF)4]
(6b)
+ 2 M'Cl + 4 H2O
resulting in 90° pulses of 12.5
unambiguous assignment of the 1H and 195Pt resonances was
l l
s for 195Pt and 12.4 s for 1H. The
Scheme 1. Preparative routes to perfluorothiolato PtII complexes (L = one mono-
dentate or half a bidentate ligand; RF = perfluoroaryl).

154
V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
2
1
3
4
14
N
13
N
N
N
N
N
12
11
MLn
MLn
N
N
9
5
6
10
dppz
phz
bpy
8
7
Scheme 2. The dppz ligand, showing the component structural features.
obtained from 1H TOCSY, 1H COSY, 1H NOESY, and gradient
selected 1H, 195Pt HMBC experiments. All 2D NMR experiments
were performed using standard pulse sequences from the Bruker
pulse program library. Chemical shifts were relative to TMS for
1H, CFCl3 for 19F and Na2[PtCl6] in D2O for 195Pt. The spectra anal-
yses were performed by the Bruker TopSpin 2 software. Elemental
analyses were carried out using a Hekatech CHNS EuroEA 3000
Analyzer. EI-MS spectra were measured with a Finnigan MAT 900
S. Simulations were performed using ISOPRO 3.0. IR spectra were
measured in ATR mode using a Perkin Elmer 400 FT-IR spectrome-
ter. UV–Vis absorption spectra were recorded with Varian Cary50
Scan spectrophotometer. Electrochemical experiments were car-
ried out in 0.1 M nBu4NPF6 solutions using a three-electrode con-
figuration (glassy carbon electrode, Pt counter electrode, Ag/AgCl
reference) and an Autolab PGSTAT30 potentiostat and function
generator. Data were processed using GPES 4.9 (General Electro-
chemical System Version 4.9). The ferrocene/ferrocenium couple
(FeCp2/FeCp+2) served as internal reference.
ated the reaction markedly and a reaction time of 1.5 h was suffi-
cient (yield: 95%).
(B) Reaction of one equivalent of HSC6F4H-4 with
[(COD)PtCl2], [(COD)Pt(Me)Cl] or [(COD)Pt(Bn)Cl]: In the pres-
ence of a small amount of KOtBu the reaction proceeded smoothly
and was complete after 2 h. The products containing Me (yield:
82%) or Bn (yield: 85%) coligands were yellow. The faint yellow
monosubstituted complex [(COD)Pt(SC6F4H-4)Cl] was obtained in
85% yield.
(C) Reaction of two equivalents of HSC6F4H-4 and KOtBu with
[(dppe)PtCl2], cis-[(PPh3)2PtCl2], [(bpy)PtCl2], and [(dppz)PtCl2]:
These reactions required the presence of two equivalents of KOtBu.
Conversion to the red phosphine complexes proceeded smoothly
within 5 h with yields, accounting to 83% for dppe, and 90% for
PPh3, while the red bpy and dppz complexes formed very slowly
and, after 3 days stirring at 298 K and workup we obtained 43%
yield for bpy and 38% for dppz.
(D) Reaction of one equivalent of HSC6F4H-4 and KOtBu with
[(dppb)Pt(C6F5)Cl]: This reaction also required the addition of one
equivalent of KOtBu. Under these conditions the red product was
obtained in 78% yield after 3 h reaction time.
2.3. Single crystal X-ray analysis
The measurements were performed using graphite-monochro-
One-pot reactions:
mated Mo K
a
radiation (k = 7.1073 Å) with an IPDS I or IPDS II
(E) Reaction of two equivalents of HSC6F4H-4 and KOtBu with
K2PtCl4 and bpy, dppz, and CF3dppz: The reaction were carried
out in acetone:MeOH:H2O 1:1:1 mixture and gave yields of 51%
for bpy, 55% for dppz, and 58% for CF3dppz after 3 d reaction time.
(F) Reaction of two equivalent of HSC6F4H-4 and KOtBu with
[(DMSO)2PtCl2] and bpy, dppz, and CF3dppz: All three reactions
gave excellent yields of 86% for bpy, 85% for dppz, and 90% for CF3-
dppz after 2 h reaction time.
(at 293 K) (STOE and Cie.) diffractometer. The structures were
solved by direct methods (SHELXS-97) [50] and refined by full-matrix
least-squares techniques against F2
(SHELXL-97) [51]. The non-
hydrogen atoms were refined with anisotropic displacement
parameters without any constraints. The hydrogen atoms were
included by using appropriate riding models.
2.4. Synthesis of the complexes
Other reactions:
(G) [(bpy)Pt(SC6F4H-4)2] was also prepared from [(COD)Pt(SC6-
F4H-4)2] by stirring 120 mg (0.18 mmol) of the precursor complex
with 35 mg (0.22 mmol) of bpy in 100 mL of toluene at 60 °C for
40 h. After reducing the volume to about 10 mL, the red precipitate
was collected by filtration and recrystallised from CH2Cl2 to yield
118 mg (0.165 mmol; 92%) of [(bpy)Pt(SC6F4H-4)2].
(H) Reaction of four equivalents of KSC6F4H-4 with K2PtCl4:
K2PtCl4 (250 mg, 0.60 mmol) and 550 mg (2.5 mmol) of KSC6F4H-
4 were suspended in 80 mL of acetone. Upon addition of a few
drops of ethanol and water, the red K2PtCl4 dissolved and the reac-
tion started. The mixture was stirred for 48 h. After filtration, the
volume of the yellow filtrate was reduced to 20 mL and the orange
product was collected, recrystallised from ethanol and dried in
vacuo yielding 400 mg (0.40 mmol) K2[Pt(SC6F4H-4)4]: C24H4F16-
K2PtS4 (997.80): Calc. C, 28.89; H, 0.40; S, 12.85. Found: C, 29.08;
H, 0.41; S, 12.60%. 1H NMR ([D6]acetone): d = 6.72 (m, 4H, H4)
ppm. 19F NMR ([D6]acetone): d = ꢀ133.3 (m, 8F, F2,6), ꢀ145.2 (m,
8F, F3,5) ppm. Note, that this work-up yielded the material without
co-crystallised EtOH (compare crystal structure).
Synthesis of the platinum complexes from their chlorido
precursor complexes, general description: The Pt precursors
[(COD)PtCl2], [(COD)Pt(Me)Cl], [(COD)Pt(Bn)Cl], [(bpy)PtCl2],
[(dppz)PtCl2], cis-[(PPh3)2PtCl2], [(dppe)PtCl2], [(dppb)Pt(C6F5)Cl],
and [(DMSO)2PtCl2] (ca. 1 mmol) were dissolved in about 50 mL
of acetone and one or two equivalents of HSC6F4H-4 + KOtBu or
KSC6F4H-4 were added. After stirring at ambient temperature for
the required time, the mixture was filtered over CeliteÒto remove
traces of elemental Pt, precipitated KCl or other undissolved mate-
rial and the filtrate was evaporated to dryness. The residues were
carefully recrystallised from acetone or CH2Cl2 to yield the prod-
ucts as microcrystalline material. Four modifications (A–D) were
applied.
(A) Reaction of two equivalents of HSC6F4H-4 with
[(COD)PtCl2]: In a first attempt an amount of 200 mg (0.534 mmol)
[(COD)PtCl2] and 200 mg (1.1 mmol) HSC6F4H-4 was stirred in
20 mL of acetone at ambient temperature. NMR monitoring
showed the intermediate formation of the mono-substituted com-
plex [(COD)Pt(SC6F4H-4)Cl]. After two days >99% conversion to the
disubstituted complex was determined. After workup, 300 mg
(0.45 mmol = 84%) of faint yellow [(COD)Pt(SC6F4H-4)2] were
obtained. Addition of small amounts (ꢁ0.2 eq) of KOtBu acceler-
(I) Attempted preparation of [(DMSO)2Pt(SC6F4H-4)2]: 120 mg
(0.28 mmol) [(DMSO)2PtCl2], 110 mg (0.60 mmol) HSC6F4H-4 and
68 mg (0.60 mmol) KOtBu were dissolved in 100 mL of acetone
and stirred at ambient temperature. After 30 min a small volume

V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
155
was separated and evaporated to dryness. 1H and 19F NMR spectra
in [D6]acetone and CDCl3 revealed the presence of cis- and trans-
[(DMSO)2Pt(SC6F4H-4)2]: 1H NMR ([D6]acetone) cis: d = 7.68 (m,
7.44–7.35 (m, 8H, Ph), 7.29 (m, 10H, Ph), 6.94 (m, 2H, H4) ppm.
19F NMR ([D6]acetone): d = ꢀ135.2 (m, 4F, F2,6), ꢀ143.8 (m, 4F,
F3,5) ppm (compare Ref. [30]). 31P NMR ([D6]acetone): d = 19.2 (s,
3
1
~
2H, H4), 3.57 (s, 6H, CH3, JPt-H = 22 Hz); trans: d = 7.68 (m, 2H,
2P, JPt,P = 3105 Hz). IR:
m
¼ 3052 w, 2959 w, 2922 m, 2852 w,
3
H4), 2.61 (s, 6H, CH3, JPt-H = 51 Hz) ppm. 1H NMR (CDCl3) cis:
1624 w, 1585 w, 1477 vs 1435 s, 1424 s, 1213 w, 1164 s, 1094 s,
3
998 w, 910 s, 880 s, 825 w, 742 s, 688 vs cmꢀ1. FIR:
¼ 688 ,
~
m
d = 7.12 (m, 2H, H4), 3.56 (s, 6H, JPt–H = 22 Hz, CH3); trans:
3
d = 7.12 (m, 2H, H4), 2.64 (s, 6H, JPt-H = 50 Hz, CH3) ppm. 19F
655, 521, 491, 305, 291, 279 cmꢀ1
.
NMR ([D6]acetone) cis and trans: d = ꢀ135.4 (m, 4F, F2,6), ꢀ140.3
(m, 4F, F3,5). After three hours stirring the mixture was filtered
over CeliteÒ and the filtrate was evaporated to dryness leaving
an orange solid which turned out to be virtually insoluble in most
organic solvent. Elemental analysis, MS and IR spectroscopy
revealed that this solid was polymeric [Pt(SC6F4H-4)2]m. C12H2F8-
PtS2 (557.34): Calc. C, 25.86; H, 0.36; S, 11.51. Found: C, 25.91;
H, 0.44; S, 11.41%. IR spectrum (pellet) of the product showed no
[(dppe)Pt(SC6F4H-4)2]: C38H26F8P2PtS2 (955.76): Calc. C, 47.75;
H, 2.74; S, 6.71. Found: C, 47.48; H, 2.61; S, 6.65%. 1H NMR
([D6]acetone): d = 8.06 (m, 10H, Ph), 7.60 (m, 10H, Ph), 6.71 (m, 2H,
H4), 2.83 (m, 4H, CH2) ppm. 19F NMR ([D6]acetone): d = ꢀ133.4
(m, 4F, F2,6), ꢀ143.7 (m, 4F, F3,5) ppm (compare Ref. [31a]) 31P
1
NMR ([D6]acetone): d = 52.2 (s, 2P, JPt,P = 3008 Hz). EI-MS: m/
z = 955 [M]+, 775 [M–C6F4S]+, 593 [Mꢀ2(HSC6F4H-4)]+, 302
[PtPC6H4]+.
bands for (DMSO)Pt (e.g.,
signals for the thiolate ligand at
m
S@O ꢂ 1120–1150 cmꢀ1) but typical
[(dppb)Pt(C6F5)(SC6F4H-4)]: C40H29F9P2PtS (969.74): Calc. C,
49.54; H, 3.01; S, 3.31. Found: C, 49.38; H, 3.01; S, 3.28%. 1H
NMR ([D6]acetone): d = 7.99 (m, 2H, Ph), 7.56 (m, 6H, Ph), 7.45
(m, 4H, Ph), 7.25 (m, 8H, Ph), 6.90 (m, 1H, H4), 3.03 (m, 2H, CH2),
2.53 (m, 2H, CH2), 2.23 (m, 2H, CH2), 1.71 (m, 2H, CH2) ppm. 19F
~
m
¼ 3069 (vw), 1629 (w), 1490
(vs), 1435 (s), 1367 (s), 1249 (w), 1229 (s), 1175 (s), 1130 (w),
918 (vs), 880 (s), 851 (s) and 712 (s) cmꢀ1 which were very similar
to those reported recently for the Pd derivative [Pt(SC6F4H-4)2]m
[38]. EI-MS: m/z = 362 [4-HF4C6S–SC6F4H-4]+, 330 [4-HF4C6-S-
C6F4H-4]+, 182 [HSC6F4H-4]+. In the filtrate of the reaction mixture,
DMSO was found (NMR). The solid can be partially re-dissolved in
[D6]DMSO giving 1H and 19F NMR signals corresponding to
[(DMSO)2Pt(SC6F4H-4)2]: 1H NMR ([D6]DMSO) cis: d = 7.79 (m,
3
NMR ([D6]acetone): d = ꢀ116.9 (m, 2F, F2,6, C6F5) JPt,F = 301 Hz,
3JF,F = 19 Hz), ꢀ131.7 (m, 2F, F2,6), ꢀ144.1 (m, 2F, F3,5), ꢀ165.4–
165.6 (m, 3F, F3,4,5, C6F5) ppm. 31P NMR ([D6]acetone): d = 12.2
2
1
(d, 1P, JP,P = 21 Hz, JPt,P = 2290 Hz, trans to C), 20.2 (d, 1P,
2JP,P = 21 Hz, JPt,P = 2960 Hz, trans to S). IR:
1478 s, 1453 s, 1433 s, 1355 m, 1226 m, 1170 m, 1102 m, 1054
m, 953 vs ( C–FC6F5), 909 vs ( C–FC6F4H), 886 m, 820 m, 786 m,
746 m, 736 s, 711 m, 690 vs cmꢀ1
¼ 1627 m, 1488 s,
1
~
m
3
2H, H4), 3.74 (s, 6H, JPt–H = 22 Hz, CH3); trans: d = 7.79 (m, 2H,
3
H4), 2.73 (s, 6H, JPt–H = 51 Hz, CH3) ppm. 19F NMR ([D6]DMSO)
m
m
cis and trans: d = ꢀ133.2 (m, 4F, F2,6), ꢀ140.0 (m, 4F, F3,5).
.
The isolated products from A–G were:
[(bpy)Pt(SC6F4H-4)2]: C22H10F8N2PtS2 (713.53): Calc. C, 37.03;
[(COD)Pt(SC6F4H-4)2]: C20H14F8PtS2 (665.53): Calc. C, 36.09; H,
2.12; S, 9.64. Found: C, 36.08; H, 2.04; S, 9.60%. 1H NMR ([D6]ace-
tone): d = 7.32 (m, 2H, H4), 5.08 (m, 4H, CODolef, 2JPt,H = 57 Hz), 2.81
(m, 8H, CODaliph) ppm. 19F NMR ([D6]acetone): d = ꢀ132.2 (m, 4F,
F2,6), ꢀ141.7 (m, 4F, F3,5) ppm. 195Pt, 1H HMBC ([D6]acetone):
~
H, 1.41; N, 3.93. Found: C, 37.08; H, 1.41; N, 3.90%. 1H NMR
3
([D6]DMSO): d = 9.66 (m, 2H, JPt,H = 33,6 Hz, bpy6,60), 8.75 (m, 2H,
bpy3,30), 8.47 (m, 2H, bpy4,40), 7.92 (m, 2H, bpy5,50), 7.37 (m, 2H,
H4) ppm. 19F NMR ([D6]acetone): d = ꢀ133.4 (m, 4F, F2,6),
~
ꢀ141.8 (m, 4F, F3,5) ppm (compare Ref. [33]). IR:
m
¼ 3102 w, br,
d = ꢀ3614 ppm. IR:
m
¼ 3081 w, 2971 w, 2745 w, 1630 m, 1485
3029 w, 2924 w, 1626 m, 1603 w, 1483 vs 1473 vs 1448 m,
vs 1430 s, 1374 m, 1249 m, 1224 s, 1167 s, 908 vs 881 s, 841 s,
820 s (sh), 708 vs cmꢀ1. EI-MS: m/z = 665 [M]+, 484 [MꢀSC6F4H]+.
[(COD)PtCl(SC6F4H-4)]: C14H13ClF4PtS (519.85): Calc. C, 32.35;
H, 2.52; S, 6.17. Found: C, 32.34; H, 2.51; S, 6.20%. 1H NMR ([D6-
]acetone): d = 7.32 (m, 1H, H4), 5.51 (m, 2H, CODolef, 2JPt,H = 57 Hz),
1427 s, 1321 w, 1243 m, 1217 m, 1168 s, 910 vs 886 s, 775 vs
710 s, 696 s cmꢀ1
.
[(dppz)Pt(SC6F4H-4)2]: C30H12F8N4PtS2 (839.64): Calc. C, 42.91;
H, 1.44; N, 6.67. Found: C, 42.88; H, 1.41; N, 6.70%. 1H NMR
3
([D6]DMSO): d = 10.02 (m, 2H, JPt,H = 33,2 Hz, dppz3,6), 9.89 (m, 2H,
5.10 (m, 2H, CODolef, 2JPt,H = 60 Hz), 2.81 (m, 8H, CODaliph.) ppm. 19
F
dppz1,8), 8.49 (dd, 2H, dppz10,13), 8.20 (m, 2H, dppz11,12), 8.10
NMR ([D6]acetone): d = ꢀ132.1 (m, 2F, F2,6), ꢀ142.2 (m, 2F, F3,5)
ppm. 195Pt, 1H HMBC ([D6]acetone): d = ꢀ3599 ppm. EI-MS: m/
z = 520 [M]+, 484 [MꢀCl]+.
(m, 2H dppz2,7), 7.41 (m, 2H, H4) ppm. 19F NMR ([D6]acetone):
~
d = ꢀ133.1 (m, 4F, F2,6), ꢀ141.7 (m, 4F, F3,5) ppm. IR:
m
¼ 3044
w, 1735 w, 1615 m, 1575 w, 1522 w, 1484 vs 1475 s, 1427 m,
1362 m, 1337 w, 1247 m, 1215 m, 1177 m, 1135 m, 1076 w,
1040 w, 1009 w, 906 m, 882 m, 817 s, 766 vs 744 s, 727 vs 709
m, 616 m, 567 w cmꢀ1. EI-MS: m/z = 839 [M]+.
[(COD)Pt(Me)(SC6F4H-4)]: C15H16F4PtS (499.43): Calc. C, 36.07;
H, 3.23; S, 6.42. Found: C, 36.08; H, 3.21; S, 6.50%. 1H NMR ([D6-
]acetone): d = 7.36 (m, 1H, H-4), 4.95 (m, 2H, CODolef, 2JPt,H = 37 Hz),
4.64 (m, 2H, CODolef
,
2JPt,H = 63 Hz), 2.49 (m, 8H, CODaliph.), 0.42 (s,
[(CF3dppz)Pt(SC6F4H-4)2]: C31H11F11N4PtS2 (907.64): Calc. C,
3H, Me, 2JPt,H = 74 Hz) ppm. 19F NMR ([D6]acetone): d = ꢀ133.2 (m,
41.02; H, 1.22; N, 6.17. Found: C, 41.08; H, 1.21; N, 6.19%. 1H
2F, F2,6), ꢀ141.5 (m, 2F, F3,5) ppm. 195Pt, 1H HMBC ([D6]acetone):
NMR ([D6]DMSO): d = 10.0 (m, 2H, JPt,H = 32 Hz dppz3,6), 9.92
3
~
d = ꢀ3564 ppm. IR:
m
¼ 3049 w, 2950 w, 2916 w, 2884 w, 2837 w,
(m, 2H, dppz1,8), 8.60 (m, 1H, dppz13), 8.42 (m, 1H, dppz10)
8.31 (m, 1H, dppz12), 8.20 (m, 2H dppz2,7), 7.41 (m, 2H, H4)
ppm. 19F NMR ([D6]DMSO): d = ꢀ103.8 (m, 3F, CF3), ꢀ133.1 (m,
~
2804 w, 1624 m, 1476 vs 1427, s, 1347 m, 1224 m, 1213 s, 1171 vs
909 vs 884 vs 845 s, 818 s, 788 s cmꢀ1. FIR:
m
¼ 684, 649, 467, 303,
~
296, 281, 228, 206, 195 cmꢀ1
.
EI-MS: m/z = 499 [M]+, 483
4F, F2,6), ꢀ141.7 (m, 4F, F3,5) ppm. IR:
m
¼ 3063 vw, 2941 w,
[MꢀCH4]+, 302 [MꢀCH4ꢀSC6F4H]+.
2857 w, 1738 w, 1710 w, 1625 m, 1615 m, 1579 m, 1526 m,
1478 vs 1421 s, 1359 s, 1251 m, 1224 s, 1163 vs 1117 m, 1072
m, 959 m, 908 vs 888 s, 813 vs 721 s, 712 s, 616 m, 563 m, 513
m cmꢀ1. EI-MS: m/z = 907 [M]+.
[(COD)Pt(Bn)(SC6F4H-4)]: C21H20F4PtS (575.52): Calc. C, 43.83;
H, 3.50; S, 5.57. Found: C, 43.88; H, 3.51; S, 5.60%. 1H NMR ([D6-
]acetone): d = 7.26 (s, 1H, H-4), 7.13–6.75 (m, 5H, Phenyl), 4.89
(m, 2H, CODolef
,
2JPt,H = 39 Hz), 4.53 (m, 2H, CODolef.
,
2JPt,H = 64 Hz),
For comparison, the previously reported complex [(bpy)Pt(SC6-
F5)2] [33] was prepared as described in (C) in 88% yield. C22H8F10-
N2PtS2 (749.50): Calc. C, 35.25; H, 1.08; N, 3.74. Found: C, 35.28; H,
2.77 (s, 2H, CH2
,
Bn
2JPt,H = 101 Hz), 2.47–2.25 (m, 8H, CODaliph
)
ppm. 19F NMR ([D6]acetone): d = ꢀ133.3 (m, 2F, F2,6), ꢀ145.2 (m,
2F, F3,5) ppm. 195Pt, 1H HMBC ([D6]acetone): d = ꢀ3742 ppm. EI-
MS: m/z = 575 [M]+.
3
1.04; N, 3.75%. 1H NMR ([D6]acetone): d = 9.87 (m, 2H, JPt,H = 32 -
Hz, bpy6,60), 8.67 (m, 2H, bpy3,30), 8.47 (m, 2H, bpy4,40), 7.92 (m,
cis-[(PPh3)2Pt(SC6F4H-4)2]: C48H32F8P2PtS2 (1081.92): Calc. C,
53.29; H, 2.98; S, 5.93. Found: C, 52.98; H, 2.91; S, 5.90%. 1H
NMR ([D6]acetone): d = 7.74 (m, 2H, Ph), 7.62–7.44 (m, 10H, Ph),
2H, bpy5,50). 19F NMR ([D6]acetone): d = ꢀ132.7 (m, 4F, F2,6),
~
ꢀ157.1 (m, 4F, F3,5), ꢀ164.8 (m, 2F, F4) ppm. IR:
m
¼ 2968 w,
2931 w, 1724 m, 1637 m, 1509 vs 1480 vs 1399 m, 1382 m,

156
V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
1364 s, 1289 m, 1118 m, 1090 vs 1021 m, 973 vs 856 vs 765 s, 725
m, 634 m, 627 m, 612 w, 548 m, 511 m cmꢀ1. EI-MS: m/z = 749
[M]+.
(SC6F4H-4)], and [(COD)Pt(Bn)(SC6F4H-4)] were obtained from
their corresponding chlorido precursors (2.4B).
In further attempts, we sought to create a one-pot procedure for
the preparation of the diimine complexes by reacting a mixture of
K2PtCl4 and the diimine ligands bpy, dppz and CF3dppz with HSC6-
F4H-4 and KOtBu but could not find a suitable solvent to dissolve
both the ligands and K2PtCl4 (various mixtures of acetone, MeOH
and water were tried). Due to the low solubilities, the reactions
were very slow and gave the desired products in only moderate
yields (50–60%). When starting from the well soluble platinum
complex [(DMSO)2PtCl2], reaction with HSC6F4H-4 and KOtBu in
acetone were much faster and very high yields were obtained
(85–90%). In view of the very simple and efficient preparation of
[(DMSO)2PtCl2] from K2PtCl4 (about 5 h, virtually 100% yield) this
method appears to be a promising alternative.
2.5. Supplementary data
Tables containing complete crystallographic and structural data
were provided together with figures showing the crystal and
molecular structures of [(COD)Pt(Me)(SC6F4H-4)], [(COD)Pt(SC6F4-
H-4)2], K2[Pt(SC6F4H-4)4], [(dppb)Pt(C6F5)(SC6F4H-4)], [(dppe)
Pt(SC6F4H-4)2] and cis-[(PPh3)2Pt(SC6F4H-4)2]. Furthermore, cyclic
voltammograms and absorption spectra of [(bpy)Pt(SC6F4H-4)2],
[(dppz)Pt(SC6F4H-4)2] and [(CF3dppz)Pt(SC6F4H-4)2] as well as
NMR spectra of cis- and trans-[(DMSO)2Pt(SC6F4H-4)2] and IR spec-
tra of [Pt(SC6F4H-4)2]m were provided.
Interestingly, reaction of cis-[(DMSO)2PtCl2] with HSC6F4H-4
and KOtBu in the absence of any other ligand resulted in a mixture
of the cis- and trans isomer of [(DMSO)2Pt(SC6F4H-4)2]. However,
only after short reaction times and rapid quenching of the reaction
mixture could these species be observed in the NMR spectrum.
Longer reaction times and usual workup lead to their complete
decomposition yielding the orange polymer [Pt(SC6F4H-4)2]m. This
polymer can be partially redissolved in DMSO underlining that the
labile DMSO ligand can prevent formation of polymeric material
only in huge excess, while the labile (chelate) ligand COD stabilises
monomeric complexes. Interestingly, the cis and trans isomers of
[(DMSO)2Pt(SC6F4H-4)2] were observed in an almost 1:1 ratio (for
a Figure see Supplementary Data), while for the chlorido derivative
[(DMSO)2PtCl2] the trans isomer has not been reported yet. Reac-
tion of K2PtCl4 with HSC6F4H-4 in an acetone:water mixture
(10:1) allowed us to isolate the compound K2[Pt(SC6F4H-4)4],
which contains the homoleptic complex dianion [Pt(SC6F4H-
4)4]2ꢀ [36b]. Finally, [(COD)Pt(SC6F4H-4)2] was successfully con-
verted to [(bpy)Pt(SC6F4H-4)2] to demonstrate the suitability of
the COD complexes as precursors.
3. Results and Discussion
3.1. Synthesis and analytical characterisation
The reaction of two equivalents of HSC6F4H-4 with the Pt pre-
cursor complexes [(N^N)PtCl2] (N^N = 2,20-bipyridine (bpy) or
dipyrido[3,2-a:20,30-c]phenazine (dppz)) (type 3 in Scheme 1) and
KOtBu as base in acetone at ambient temperature proceeds very
slowly due to the low solubility of the precursor complexes in this
medium. After about three days and work-up we obtained the red
products [(N^N)Pt(SC6F4H-4)2] in rather low yields of 43% and 38%
(for details see Section 2). The synthesis of the bpy complex, using
Pb(SC6F4H-4)2 was reported to yield 61% [33]. The former reac-
tions carried out with the phosphane complexes cis-[(PPh3)2PtCl2],
[(dppe)PtCl2], and [(dppb)Pt(C6F5)Cl] (one equivalent of HSC6F4H-
4) were finished within 5 h and gave good yields (80–90%). For
both diimine and phosphine complexes the use of HSC6F4H-4 with-
out base (route 4) results in very slow reaction rates. In contrast to
this, the Pt complex [(COD)PtCl2] (COD = 1,5-cyclooctadiene) could
be reacted with HSC6F4H-4 without the addition of KOtBu, but
completion was observed only after 2 days. Upon addition of
KOtBu the faint yellow product [(COD)Pt(SC6F4H-4)2] was obtained
in 1.5 h in 95% yield. Recently, the same complex has been
obtained by reacting Pb(SC6F4H-4)2 with [(COD)PtCl2] in 96% yield
[36]. We also prepared [(COD)PtCl(SC6F4H-4)] using one equivalent
HSC6F4H-4 in a reasonable yield of 85% with almost no by-products
[(COD)Pt(SC6F4H-4)2] and [(COD)PtCl2], which could be expected
from a non-selective (statistical) reaction. Also, [(COD)Pt(Me)
3.2. NMR spectroscopy
19F [52] and 195Pt [53] NMR spectroscopy was a very useful
method to monitor the identity of the corresponding complexes
and their occurrence in reaction mixtures. Table 1 lists some data
(the full data is available in Section 2).
From earlier studies it is well known that the 2JPt,H(=CH,COD) cou-
pling constants reflect very well the general Pt–ligand bond
Table 1
Selected chemical shifts and coupling constants of the platinum complexes.a
d (19F) (F2,6)
d (19F) (F3,5)
d (1H) (H4)
d (195Pt)
nJPt,E
[(COD)Pt(SC6F4H-4)2]
[(COD)Pt(Me)(SC6F4H-4)]
[(COD)Pt(Bn)(SC6F4H-4)]
[(COD)PtCl(SC6F4H-4)]
K2[Pt(SC6F4H-4)4]
cis-[(PPh3)2Pt(SC6F4H-4)2]
[(dppe)Pt(SC6F4H-4)2]
[(dppb)Pt(C6F5)(SC6F4H-4)]
[(bpy)Pt(SC6F4H-4)2]
[(dppz)Pt(SC6F4H-4)2]
[(CF3dppz)Pt(SC6F4H-4)2]
cis-[(DMSO)2Pt(SC6F4H-4)2]
trans-[(DMSO)2Pt(SC6F4H-4)2]
[(bpy)Pt(SC6F5)2]
ꢀ132.1
ꢀ133.2
ꢀ133.3
ꢀ132.2
ꢀ133.3
ꢀ135.2
ꢀ133.4
ꢀ131.7
ꢀ134.2
ꢀ133.1
ꢀ133.9
ꢀ135.4
ꢀ135.4
ꢀ132.7
ꢀ142.2
ꢀ141.5
ꢀ145.2
ꢀ141.7
ꢀ145.2
ꢀ143.8
ꢀ143.7
ꢀ144.1
ꢀ144.8
ꢀ141.7
ꢀ143.4
ꢀ140.3
ꢀ140.3
ꢀ157.1
7.02
7.36
7.26
7.32
6.72
6.94
6.71
6.97
7.01
7.04
7.05
7.68
7.68
–
ꢀ3614
57b
ꢀ3564
63, 37b
64, 39b
57, 60b
–
ꢀ3742
ꢀ3599
–
–
–
–
–
–
–
–
–
–
3105c
3008c
2960, 2290c
36.0d
33.2d
32.0d
22e,f
51e,f
36.7d
a
b
c
d
e
f
Measured in [D6]acetone; chemical shifts d in ppm, coupling constants J in Hz.
2JPt,H(@CH,COD), for unsymmetrical complexes the first number refers to the @CH group trans to SC6F4H-4, the second to the @CH group trans to R0 or Cl.
1JPt,P.
3JPtNCH
.
3JPt,CH3
For cis-[(DMSO)2PtCl2] a 22.7 Hz JPt,CH3 coupling is observed at 3.54 ppm in [D6]acetone.
.
3

V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
157
strength of a ligand trans to the corresponding olefin proton in
CODPt complexes [54]. Table 1 shows a 2JPt,H(=CH,COD) coupling con-
stant of 57 Hz for the symmetric complex [(COD)Pt(SC6F4H-4)2]
putting the SC6F4H-4 coligand with relatively weak coligands
alongside alkynyls (ꢁ50 Hz) or halides (ꢁ70 Hz). For comparison,
[(COD)Pt(Me)2] has a coupling constant of 41 Hz (for the strong
Me ligand), while [(COD)PtCl2] gives 69 Hz for the weak Cl ligand
[54], In the ‘‘unsymmetric’’ complexes [(COD)Pt(R0)(SC6F4H-4)]
(R0 = Me, Bn) the situation is slightly modified. The thiolate coli-
gands seem to lose some of their binding strength (increased trans
2JPt,H), while the methyl and benzyl coligands reveal their very high
ligand strength (decreased trans 2JPt,H). The same phenomenon has
been observed for [(COD)Pt(Me)Cl], where the corresponding val-
ues are 74 and 32 Hz [54]. Maybe the increased electron-donation
H-4)2]. As for the COD complexes, the S ligand exerts almost the
same ligands strength as the chlorido ligand in [(DMSO)2PtCl2]
(Table 1). The value for the trans isomer exceeds by far those of
related
organoplatinum
complexes
trans-[(DMSO)2Pt(R)2]
(R = alkyl or aryl) which are around 30 Hz [57b]. The latter study
showed that the trans configuration is observed for bulky coligands
in bis-DMSO complexes, while the cis configuration is more stable
for electronic reasons. Since SC6F4H-4 and Cl exhibit approximately
the same ligand strength, the bulkiness of the thiolate coligand
must thus be responsible for the observation of the trans isomer.
Another important NMR parameter is the 195Pt NMR shift,
which lies in the typical range of PtII complexes for the investigated
complexes [53]. Although no correlation can be drawn between the
(electronic) structure of the complexes and the chemical shift val-
ues, the exceedingly broad scale of the 195Pt shift usually allows the
unequivocal detection of such complexes even in complex mix-
tures [58,61].
by the alkyl ligand requires efficient
in stark contrast with the rather poor
p
p
back-donation, which stands
donating ability of the thio-
late ligand in the symmetrical complexes. An interesting situation
is found in [(COD)PtCl(SC6F4H-4)], here Cl and SC6F4H-4 exert
seemingly similar bond strength, SC6F4H-4 being only slightly
stronger. In corresponding dithiolate complexes [(COD)Pt(S2R)]
3.3. Crystal and molecular structures
2
smaller trans JPt,H values were found (S2R = SCH2-CH2S (dt):
From acetone solutions of the compounds [(COD)Pt(SC6F4H-
4)2], [(COD)Pt(Me)(SC6F4H-4)], [(dppe)Pt(SC6F4H-4)2] [(dppb)Pt(C6-
F5)(SC6F4H-4)] and cis-[(PPh3)2Pt(SC6F4H-4)2]ꢃ3acetone single crys-
tals were obtained, while [K2(EtOH)2{Pt(SC6F4H-4)4}] crystallised
from EtOH solution. Suitable single crystals were submitted to X-
ray diffraction and crystal and molecular structures were deter-
mined. Figs. 1–3 show all structures, Tables 2–4 list the corre-
sponding data (further Figures are in the Supplementary Data).
The crystal structures of the two crystallographically isostruc-
tural COD Pt complexes (monoclinic P21/c) do not exhibit pro-
nounced intramolecular interactions. Only for the symmetric
53 Hz; or SCH = CHS (edt): 53 Hz; SC(CN)=C(CN)S (mnt): 54 Hz),
indicative of much higher ligand strength [55].
n
Also other JPt,X coupling constant have been very successfully
correlated with the strength of trans Pt–ligand bonds [55–60]. In
our study, the cis-configuration of cis-[(PPh3)2Pt(SC6F4H-4)2] is
1
clearly reflected in the large JPt,P coupling constant, which lies in
the same range as found for the other two and related cis-config-
ured bis-phosphine Pt complexes [55–57,60]. For the correspond-
ing dithiolate complexes [(PPh3)2Pt(S2R)] only slightly smaller
1JPt,P coupling constants of ꢁ2900 Hz were found [55], which indi-
cates an only slightly increased trans influence (ligand strength) for
the dithiolates (S2R) compared with SC6F4H-4. For the mixed com-
plex [(dppb)Pt(C6F5)(SC6F4H-4)] the same phenomenon as dis-
complex [(COD)Pt(SC6F4H-4)2] weak intermolecular SR.F. .SRF
p
stacking interactions were found (Table 4; Figures in the Supple-
mentary Data). A closer look reveals centroid distances of about
3.72 Å, which, together with the observed offset of the aromatic
rings, points to only very weak attractive interactions [62].
1
cussed for the COD complexes was found. While JPt,P for the P
atom trans to the C6F5 coligand is markedly smaller (thus the Pt–
1
P bond longer = weaker), JPt,P for the P atom trans to the SC6F4H-
Corresponding intramolecular
p stacking interactions are far
4 coligand is slightly increased compared with the symmetric
derivatives. The same situation is found in [(dppe)Pt(C6F5)(SC6F5)],
which exhibits JPt,P of 2936 (trans to SC6F5) and 2320 Hz (trans to
weaker. The same has been concluded for the related
complexes [(COD)Pt(SC6F4(CF3)-4)2] (monoclinic C2/c) [36a], and
[(COD)Pt(Me)(SC6H5)] [63]. The molecular structures of the two
complexes (Fig. 1) exhibit perfect planar stereochemistry of the
Pt atoms (sum of angles ꢁ360°), and XꢀPtꢀX angles of ꢁ86° (X
represents the C@C centroids), very similar to related COD Pt com-
plexes [36a,54,55,63,64]. Also, the PtꢀS [36a,55,63] and PtꢀX bond
lengths are in the range of comparable compounds. A closer look
reveals that in the mixed complex [(COD)Pt(Me)(SC6F4H-4)], two
markedly different PtꢀX bond lengths were found (ꢁ2.02 Å for
the PtꢀX bond trans to the thiolate coligand and ꢁ2.20 Å trans to
the Me coligand), values which, in line with the NMR data, reflect
1
C6F5) [34], or [(dppb)Pt(C6F5)Cl], with 1JPt,P values of 3776 (trans to
Cl) and 2149 Hz (trans to C6F5) [59], Finally, in [(dppb)Pt(C6F5)(H2-
O)]+, containing the very weak H2O ligand, the 1JPt,P values are 4530
and 2140 Hz [59]. Thus, while in the COD complexes the SC6F4H-4
coligand shows a trans influence (and thus ligand strength) only
slightly superior to Cl, in phosphine complexes SC6F4H-4 is mark-
edly stronger than Cl and reaches almost the strength of C6F5.
3
A remarkable difference for the JPt-CH3 coupling was observed
for the cis (22 Hz) vs. trans (51 Hz) isomers of [(DMSO)2Pt(SC6F4-
Fig. 1. Molecular structures of [(COD)Pt(SC6F4H-4)2] (left) and [(COD)Pt(Me)(SC6F4H-4)] (right) at 50% probability level (with numbering); protons were omitted for clarity.

158
V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
Fig. 2. Crystal structure (left) of [K2(EtOH)2{Pt(SC6F4H-4)4}] and a view of the dianionic complex [Pt(SC6F4H-4)4]2ꢀ at 50% probability level (with numbering); protons were
omitted for clarity (right).
Fig. 3. Molecular structure of [(dppb)Pt(C6F5)(SC6F4H-4)] at 50% probability level (with numbering); protons were omitted for clarity (left) and view of two molecules in the
crystal showing multiple p-stacking interactions (compare Table 4) (right).
the different ligand strength of the coligands. The same has been
observed e.g. for [(COD)Pt(Me)Cl] [54,64a].
(Fig. 3, Table 4), but very probably they have no impact on the
molecular structures. The complex cis-[(PPh3)2Pt(SC6F4H-4)2] has
been structurally characterised before in the solvate cis-[(PPh3)2-
Pt(SC6F4H-4)2]ꢃCH2Cl2 (monoclinic P21/n) [30] with essentially
the same bonding parameters. In addition, cis-[(PPh3)2Pt(SC6F5)2]-
ꢃMeOH (monoclinic C2/c) [30] has been reported with very similar
parameters.
In the crystal structure of [K2(EtOH)2{Pt(SC6F4H-4)4}] (Fig. 2)
weak intramolecular
p stacks were found, the potassium ions exhi-
bit contacts with EtOH O atoms (2.76 and 2.80 Å), F atoms (2.81,
2.84, 3.05 Å) and S atoms (3.25, 3.30, 3.32 Å) making a coordination
number of eight in a very distorted square prismatic arrangement.
The molecular structure of the dianion [Pt(SC6F4H-4)2]2ꢀ in [K2-
(EtOH)2{Pt(SC6F4H-4)4}] reveals an almost perfect square planar
stereochemistry of the Pt atom (Fig. 2). For this crystal structure,
there is, to our knowledge, no precedent. However, the crystal
The crystal structure of [(dppe)Pt(SC6F4H-4)2] has not been
ꢀ
reported before, however, the Ni (triclinic P1) [31a] and Pd (mono-
clinic C2/c) [29c] analogues have been reported, the latter together
with the very similar complexes [(dppe)Pt(SC6F5)2] (C2/c) and
ꢀ
structure of the binuclear [Bu4N]2[(4-HF4C6S)2Pt(l-SC6F4H-4)2-
[(dppe)Pt(SC6H4(CF3)-4)2] (P1) [29c]. A comparison of the Ni, Pd
Pt(SC6F4H-4)2] (P21/n) (together with the corresponding SC6F5
and Pt analogues [(dppe)M(SC6F4H-4)2] reveals that the M–P and
M–S distances increase along the series Ni ꢄ Pt < Pd, which is in
line with the generally assumed smaller size of Pt(II) compared
with Pd(II) [68].
In the complex [(dppb)Pt(C6F5)(SC6F4H-4)] (Fig. 3) the PtꢀS dis-
tance is virtually identical with the values in the other phosphine
complexes. Interestingly, also in complexes of electron-rich aryl-
thiolates as in [(dppb)Pt(SC6H3(CH3)2-2,6)2] (orthorhombic Pbca),
this distance is non-variant around 2.36 Å [56]. As expected from
the two different coligands, the PtꢀP distances in [(dppb)Pt(C6F5)
(SC6F4H-4)], 2.299(1) Å for the PtꢀP bond trans to the C6F5 coligand
and 2.267(1) Å for the bond trans to SC6F4H-4, are very different.
and SC6F4(CF3)-4 derivatives) [37] and the hetero trinuclear
compound [Cl(Cp⁄)Ir( -SC6F4H-4)2Ir(Cp⁄)Cl]
l-SC6F4H-4)2Pt(l
(Cp⁄ = pentamethyl-cyclopentadienide) formally containing the
coordinated [Pt(SC6F4H-4)4]2ꢀ dianion [65] were reported with
quite similar bonding parameters. Also, in the hetero tetranuclear
complex [(C6F5)Pd{(
ingly, also in the non-fluorinated derivatives [Et4N]2[Pt(SC6H5)4]
[66] and [Pt3( -SC6H4(CH3)-4)4(dppm)2](CF3SO3)2 [67] the bond-
l
-C6F5)2Pt}Pd(C6F5)2]2ꢀ [31b] and interest-
l
ing parameters around Pt are essentially the same.
In the crystal structures of the three phosphine complexes weak
intra- and inter molecular
p stacking interaction were found

V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
159
Table 2
Parameters of crystal structure measurements, refinement and selected structural data of COD Pt complexes and K2[Pt(SC6F4H-4)4]ꢃ2EtOH.a
[(COD)Pt(SC6F4H-4)2]
[(COD)Pt(Me)(SC6F4H-4)]
[K2(EtOH)2{Pt(SC6F4H-4)4}]
Formula
C
20H14F8Pt1S2
C15H16F4Pt1S1
499.43
monoclinic
P21/c
11.7018(19)
8.5594(8)
15.453(2)
90
94.347(18)
90
1543.3(4) / 4
2.149
C28H14F16Pt1K2O2S4
1089.94
Weight (g molꢀ1
Crystal system
Space group
a (Å)
)
665.52
monoclinic
P21/c
12.184(2)
7.0615(8)
23.563(4)
90
90.816(15)
90
2027.1(5) / 4
2.181
triclinic
ꢀ
P1
7.9915(11)
8.6162(12)
13.0032(19)
98.254(17)
99.219(17)
95.491(16)
868.2(2) / 4
2.085
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
V (Å)3/Z
qcalc (g cmꢀ3
l
)
(mmꢀ1
)
7.205
9.258
4.636
Limiting indices
Reflections collected/unique
Rint
ꢀ15 < h < 15, ꢀ8 < k < 9, ꢀ30 < l < 30
ꢀ15 < h < 15, ꢀ10 < k < 10, ꢀ20 < l < 20
ꢀ10 < h < 10, ꢀ11 < k < 11, ꢀ17 < l < 17
20779/4499
14220/3529
0.0900
10450/3873
0.0607
0.0919
Data/restraints/parameters
4499/0/281
0.755
3529/0/191
0.935
3873/0/241
0.886
Goodness-of-fit on F2
Final R1, wR2 (I > 2
R1, wR2 (all data)
D
r
(I))
0.0321, 0.0381
0.1074, 0.0468
ꢀ2.286/1.265
0.0457, 0.0956
0.0816, 0.1048
ꢀ1.178/1.473
0.0327, 0.0514
0.0480, 0.0551
ꢀ1.246/1.221
qmin/max (10ꢀ6 e/pm3)
Distances (Å)
Pt–S
2.318(2), 2.324(2)
–
2.075(2), 2.103(3)
2.288(3)
2.050(11)
2.017(3), 2.170(3)
2.334(1), 2.341(1)
–
–
Pt–CMe
Pt–Xb
Angles (°)
S–Pt–S
96.45(8)
–
90.45(4), 89.55(4)
S–Pt–CMe
–
82.90(40)
84.79(50)
91.46(42)
100.82(38)
359.97(32)
111.10(30)
–
–
–
–
X–Pt–Xb
85.59(38)
–
89.79(59), 88.83(54)
360.66(45)
110.00(30), 108.40(20)
X–Pt–CMe
X–Pt–Sb
Sum of angles Pt
C–S–Pt
360.00(4)
106.94(15), 109.93(15)
a
Radiation wavelength k = 0.71073 Å; T = 293(2) K; refinement method: full-matrix least-squares on F2.
X: Centroids of the C@C double bond.
b
The same was observed in [(dppb)Pt(C6F5)(H2O)](SO3CF3)ꢃH2O [69]
with 2.312(3) Å for the PtꢀP bond trans to the C6F5 coligand and
2.212(3) Å for the bond trans to the very weak H2O ligand.
C6H4(NO2)-4, C6H4(OMe)-4, C6H4(NMe2)-4 and C6H5 [26,27], and
the corresponding Pd complex [(bpy)Pd(SC6F4H-4)2] [38] have
been studied in detail, we embarked on a brief study of the new
diimine Pt complexes.
The cyclic voltammetry of the three new Pt complexes revealed
two one-electron reduction waves and one oxidation wave in
MeCN solution (data in Table 5, figures in the Supplementary
Data), which has also been observed for related Pt complexes
(Table 5) [26,27]. Within the series of the three complexes with
When comparing all PtꢀS distances, the phosphine complexes
have the longest (about 2.36–2.38 Å), followed by the homoleptic
complex [Pt(SC6F4H-4)4]2ꢀ (ꢁ2.33 Å) and the symmetric COD com-
plex (2.32 Å). The shortest PtꢀS bond lengths were observed in the
unsymmetrical COD complex (2.29 Å) and the bpy complex
[(bpy)Pt(SC6F4H-4)2] (ꢁ2.29 Å) [33]. Most surprising in this series
is that the PtꢀS bond length for the unsymmetric COD complex
is shorter than the values for the symmetric complex. This stands
in contrast to our conclusions from NMR spectroscopy, where the
the SC6F4H-4 ligand increasing
p-accepting ability of the N^N
ligand bpy < dppz < CF3dppz [43] facilitates the reduction (increas-
ing potentials), while the energy of the long-wavelength MLCT
absorption decreases. At the same time the decreasing oxidation
potentials along the same series reflects the decreasing donor
capacity of these N^N ligands. Interestingly, the dppz and bpy
complex exhibit rather identical first reduction potentials, while
the oxidation potentials are different. Even more striking is the dif-
ference in the second reduction potential. A closer view reveals
that for dppz the difference between first and second reduction lies
markedly below the typical 0.63 V for the first and second reduc-
tion of diimines, such as bpy [43]. This nicely reflects that dppz fea-
tures two very close low-lying unoccupied MO, one of bpy-
character, one of phenazine character. The more or less identical
first reduction potential points to the fact, that in [(dppz)Pt(SC6F4-
H-4)2] the reduction occurs at the bpy-centred LUMO, while for the
second reduction the phenazine type LUMO seems to be the target.
For the CF3 derivative both reductions seem to occur at the bpy-
centred LUMO (lowered presumably by the electron-withdrawing
effect of the substituent. As a consequence of the more electron-
demanding C6F5 group compared with the C6F4H-4, the complex
2
unsymmetric complex shows an increased trans JPt,H coupling
constant compared with the symmetric dithiolate derivative,
indicative of decreased bond strength of the SC6F4H-4 coligand.
From the NMR data we have also concluded that in phosphine
complexes the SC6F4H-4 coligand exhibits markedly higher ligand
strengths than in the COD complexes, which conclusion stands also
in contrast with the above series of decreasing Pt–S distances (from
phosphines to COD). However, structural data represents bond dis-
tances in the restrained surrounding of a crystal and includes the
effects of crystal packing or intermolecular interaction such as
p
stacking, while NMR coupling constants of molecules in solution
can be far better correlated with bond (or ligand) strength [54,57].
3.4. Electrochemistry and UV–Vis absorption spectroscopy of
[(N^N)Pt(SC6F4H-4)2] complexes
Since the electrochemical and photophysical properties of the
related Pt complexes [(bpy)Pt(SR)2] with R = C6F5, C6F4(CN)-4,

160
V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
Table 3
Parameters of crystal structure measurements, refinement and selected structural data of SC6F4H-4 platinum complexes with phosphane ligands.a
cis-[(PPh3)2Pt(SC6F4H-4)2]ꢃ3acetone
57H50F8Pt1P2S2O3
1256.12
monoclinic
P21/c
9.5868(9)
[(dppe)Pt(SC6F4H-4)2]
[(dppb)Pt(C6F5)(SC6F4H-4)]
Formula
C
C38H26F8Pt1S2
955.74
monoclinic
C2/c
C40H29F9P2Pt1S1
969.72
monoclinic
P21/c
Weight (g molꢀ1
Crystal system
Space group
a (Å)
)
18.805(2)
12.5390(11)
b (Å)
20.9851(17)
12.7754(10)
16.8347(16)
c (Å)
26.889(3)
15.8250(17)
20.704(2)
a
(°)
90
90
90
b (°)
97.003(8)
107.634(9)
122.207(7)
c
(°)
90
90
90
V (Å)3/Z
5369.1(8)/6
1.554
2.822
3623.3(7)/4
1.752
4.145
3695.6(7)/4
1.742
4.012
qcalc (g cmꢀ3
l
)
(mmꢀ1
)
Limiting indices
Reflections collected/unique
Rint
ꢀ11 < h < 11, ꢀ25 < k < 24, ꢀ31 < l < 31
ꢀ24 < h < 24, ꢀ16 < k < 16, ꢀ18 < l < 18
ꢀ16 < h < 16, ꢀ22 < k < 22, ꢀ27 < l < 27
36915/9313
0.0734
20965/3988
0.0540
34026/8793
0.1368
Data/restraints/parameters
9313/0/646
0.956
3988/0/232
1.047
8793/0/507
0.901
Goodness-of-fit on F2
Final R1, wR2 (I > 2
R1, wR2 (all data)
D
r
(I))
0.0416, 0.0902
0.0869, 0.1274
ꢀ3.948/3.313
0.0239, 0.0572
0.0275, 0.0588
ꢀ0.674/0.949
0.0377, 0.0621
0.0762, 0.0694
ꢀ0.807/0.971
qmin/max (10ꢀ6 e/pm3)
Distances (Å)
Pt–S
Pt–P
2.366(2), 2.380(2)
2.295(2), 2.304(2)
–
2.361(1), 2.361(1)
2.254(1), 2.254(1)
–
2.367(2)
2.267(1), 2.299(1)
2.046(7)
Pt–C
Angles (°)
S–Pt–S
93.78(7)
98.80(4)
–
S–Pt–P
P–Pt–P
P–Pt–C
S–Pt–C
Sum of angles Pt
C–S–Pt
86.40(8), 84.25(8)
95.97(8)
–
–
360.40(8)
109.10(30), 108.80(30)
87.76(3), 87.76(3)
85.74(4)
–
–
360.06(4)
110.74(11)
86.84(5)
94.54(5)
90.06(18)
88.54(18)
359.98(12)
103.30(20)
a
Radiation wavelength k = 0.71073 Å; T = 293(2) K; refinement method: full-matrix least-squares on F2.
Table 4
Distances (Å) and angles (°) of
p contacts.
Type
Angle
Centroid distance
Offset
Inter-planar distance
[(COD)Pt(Me)(SC6F4H-4)]
[(COD)Pt(SC6F4H-4)2]
None
–
–
–
–
Intra SRF
Inter SRF
Intra SRF
Intra SRF::RF
Intra RF::Ph
Inter SRF
Intra SRF
Intra SRF
Intra Ph
2.94(29)
2.94(26)
12.67(16)
16.52(20)
22.63(29)
0.00(30)
4.39(16)
9.26(16)
7.68(19)
4.239(3)
3.725(3)
3.587(6)
3.546(5)
3.635(5)
3.614(5)
3.869(5)
3.888(3)
3.845(3)
1.932(3)
1.545(3)
0.173(6)
0.861(5)
0.689(5)
1.358(5)
1.183(5)
1.686(3)
0.271(3)
3.874(3)
3.390(3)
3.583(6)
3.440(5)
3.569(5)
3.349(5)
3.684(5)
3.504(3)
3.844(3)
[K2(EtOH)2{Pt(SC6F4H-4)4}]
[(dppb)Pt(C6F5)(SC6F4H-4)]
[(dppe)Pt(SC6F4H-4)2]
cis-[(PPh3)2Pt(SC6F4H-4)2]ꢃ3acetone
Table 5
Electrochemical and UV–Vis absorption data of [(N^N)Pt(SC6F4H-4)2] and related complexes.a
Electrochemical data
UV–Vis data kmax [nm] (e
[103 Mꢀ1 cmꢀ1])
Oxidation
Reductions/Ered1 ꢀ Ered2
ꢀ1.64, ꢀ2.27/0.63
[(bpy)Pt(SC6F5)2]
[(bpy)Pt(SC6F4H-4)2]
0.79
0.76
0.66
0.62
0.77
0.95
0.22
408 (3.0)
416 (3.7)
430 (3.0)
463 (2.8)
414 (3.2)b
383 (3.0)b
498 (2.1)b
ꢀ1.62, ꢀ2.26/0.64
ꢀ1.62, ꢀ2.18/0.56
ꢀ1.56, ꢀ2.20/0.64
ꢀ1.60, ꢀ2.29/0.69
ꢀ1.54, ꢀ2.14/0.60
ꢀ1.72, ꢀ2.37/0.65
[(dppz)Pt(SC6F4H-4)2]
[(CF3dppz)Pt(SC6F4H-4)2]
[(bpy)Pt(SC6F5)2] [27]
[(bpy)Pt(SC6F4(CN)-4)2] [27]
[(bpy)Pt(SC6H5)2] [26,27]
a
Electrochemical potentials [V], measured in 0.1 M nBu4NPF6/MeCN at 298 K, scan rate 100 mV/s and long-wavelength absorption maxima kmax [nm] with extinction
coefficients
e
[103 Mꢀ1 cmꢀ1], measured in MeCN.
b
In DMF.

V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
161
[(bpy)Pt(SC6F5)2] exhibits a slightly greater reduction potential, a
higher oxidation potential and higher absorption energy than the
SC6F4H-4 derivative, although the differences are far smaller than
those observed for different N^N ligands. For the SC6H5 Pt complex
the oxidation potential is markedly lowered, by about 0.5 V, com-
pared with the SC6F5 derivative, while the introduction of the
the LUMO energy, (ii) substitution on the thiolate ligand by
electron-demanding F atoms decreases the HOMO energy, while
(iii) Pt derivatives exhibit intrinsically smaller HOMO–LUMO gaps
compared with Pd complexes and also provide more stable binding
in corresponding [(L)2M(SR)2] or [(L^L)M(SR)2] (L or L^L, any ligand
or chelate ligand; M = Pd or Pt) complexes with respect to
unwanted formation of oligomeric or polymeric [M(SR)2]m. In the
latter respect fluorinated derivatives (SRF) proved to be superior
to non-fluorinated compounds (SR). Thus from the viewpoint of
the application of such complexes in photoactive materials the Pt
(compared with Pd) derivatives with per-fluorinated ligands (com-
pared with non-fluorinated) are quite promising. Thus, in future
investigation we will explore such possibilities.
SC6F4(CN)-4 coligand results in
a higher oxidation potential
(+0.2 V). This clearly underlines that the LUMO is essentially
p⁄(N^N)-centred, while the HOMO is metal-centred, although with
appreciable contributions from the thiolate coligand [26,27].
When comparing the Pt complexes with the Pd derivative
[(bpy)Pd(SC6F4H-4)2], for the latter both the difference of first oxida-
tion and reduction potential (0.88 V; ꢀ1.54 V in MeCN) and the
absorption energy (363 nm) is larger. This larger HOMO–LUMO
gap is in line with the second ionisation potential of the two metals
(18.6 eV for Pt and 19.4 eV for Pd) and the electron binding energy of
the valence p electrons (51.7 eV for Pt 5p and 50.9 eV for Pd 4p)
[38,70], in other words, the slightly less noble character of Pd
compared with Pt. At the same time the extinction coefficient of
the Pd derivative is markedly bigger (ꢁ10000 compared with
ꢁ3000 Mꢀ1 cmꢀ1), which might be due to a larger contribution of
Acknowledgements
We are indebted to Dr. Wieland Tyrra for NMR experiments
(University of Cologne). We are also grateful for a loan of K2PtCl4
by Johnson Matthey (J.M.) and for financial support by Deutsche
Forschungsgemeinschaft KL 1194/11-1 (A.L. and A.K.). V.L.
acknowledges a grant from Heinrich Hertz-Stiftung.
p–
p⁄ or L0(SRF)-to-L(N^N)-charge transfer character to this absorption
[14,26,27].
Appendix A. Supplementary material
CCDC 943480 for [(COD)Pt(SC6F4H-4)2], 943481 for
[(COD)Pt(Me)(SC6F4H-4)], 943482 for K2[Pt(SC6F4H-4)4]ꢃ2EtOH,
943483 for cis-[(PPh3)2Pt(SC6F4H-4)2]ꢃ3acetone, 943484 for
[(dppe)Pt(SC6F4H-4)2] and 943485 for [(dppb)Pt(C6F5)(SC6F4H-4)]
contains the full crystallographic data for this paper. These data
can be obtained free of charge from The Cambridge Crystallo-
graphic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.ica.2014.07.058.
4. Conclusions and outlook
In this work we explored formation reactions leading to Pt com-
plexes [(L)2Pt(SRF)2] with COD (cycloocta-1,5-diene), diimine, or
phosphine ligands (L) and the SC6F4H-4 coligand (SRF). Direct reac-
tion of HSC6F4H-4 with the corresponding [(L)2PtCl2] precursor
complexes was accelerated by addition of traces of KOtBu for the
COD complexes. For the diimine or phosphine derivatives equimo-
lar amounts of KOtBu were necessary to ensure rapid conversion
(ꢁ2 h) and reasonable yields (60–80%). The one-pot procedure
using [(DMSO)2PtCl2] the diimine ligand and HSC6F4H-4 / KOtBu
gave excellent yields (>90%). Thus, a number of previously reported
and new COD, diimine or phosphine Pt complexes with the SC6F4H-
4 coligand were prepared in high yields and purity without the use
of sophisticated or toxic precursors such as (NBu4)2[Pt(SC6F4H-4)4],
Tl(SC6F4H-4) or Pb(SC6F4H-4)2. Remarkably, these metathetical
reactions (exchange of Cl-coligand for SC6F4H-4) tolerate also
rather labile ligands such as COD and DMSO and allow the prepa-
ration of such complexes in high yield in contrast to the corre-
sponding Pd derivatives which undergo rapid cleavage of COD
and DMSO with formation of oligomers or polymers [Pd(SRF)2]m
under the same reaction conditions. Most of the compounds could
be structurally characterised by single crystal XRD in the solid and
all of them by multi-nuclear NMR spectroscopy in solution. The
previously unreported structure of K2[Pt(SC6F4H-4)4] (prepared
from KSC6F4H-4 and K2PtCl4) revealed an almost perfect square
planar PtS4 coordination with Pt–S distances at ꢁ2.33 Å, which is
longer than found for the COD complexes or diimine derivatives
but markedly shorter than Pt–S distances in phosphine complexes.
Thus, Pt–S distances markedly reflect the donor strength of the
trans ligand. At the same time, the Pt–S bond length in such
[Pt(SR)4]2ꢀ dianions seems to be rather invariant concerning sub-
stituents (R = C6F5 or C6H5), and provides a highly stable scaffold.
The absorption spectroscopy and electrochemistry of the diimine
complexes [(N^N)Pt(SC6F4H-4)2] with N^N = bpy and the better
References
[1] W. Beck, K. Stetter, Inorg. Nucl. Chem. Lett. 2 (1966) 383.
[2] (a) W. Beck, K.H. Stetter, S. Tadros, K.E. Schwarzhans, Chem. Ber. 100 (1967)
3944;
(b) W. Beck, W.P. Fehlhammer, K.H. Stetter, S. Tadros, Chem. Ber. 100 (1967)
3955;
(c) W. Beck, S. Tadros, Z. Anorg. Allg. Chem. 375 (1970) 231.
[3] R.S. Nyholm, J.F. Skinner, M.H.B. Stiddard, J. Chem. Soc. A (1968) 38.
[4] R.H. Fenn, G.R. Segrott, J. Chem. Soc. A (1970) 2781.
[5] (a) J.A. Mahar, M.E. Peach, J. Fluorine Chem. 31 (1986) 121;
(b) M.E. Peach, J. Inorg. Nucl. Chem. 35 (1973) 1046;
(c) C.R. Lucas, M.E. Peach, Can J. Chem. 48 (1970) 1869;
(d) M.E. Peach, Can. J. Chem. 46 (1968) 2699.
[6] A. Singhal, V.K. Jain, B. Varghese, E.R.T. Tiekink, Inorg. Chim. Acta 285 (1999)
190.
[7] (a) J. Chatt, F.A. Hart, J. Chem. Soc. (1960) 2807;
(b) J. Chatt, F.A. Hart, J. Chem. Soc. (1953) 2363.
[8] (a) P.H. Kreutzer, K.T. Schorpp, W. Beck, Z. Naturforsch. B 30 (1975) 544;
(b) B. Kreutzer, P. Kreutzer, W. Beck, Z. Naturforsch. B 27 (1972) 461;
(c) W. Beck, K. von Werner, Chem. Ber. 104 (1971) 2901.
[9] R. Zanella, R. Ros, M. Graziani, Inorg Chem. 12 (1973) 2736.
[10] (a) V.K. Jain, S. Kannan, R.J. Butcher, J.P. Jasinski, J. Chem. Soc., Dalton Trans.
(1993) 1509;
(b) C. Xu, J.W. Siria, G.K. Anderson, Inorg. Chim. Acta 206 (1993) 123.
[11] Q. Chen, F. Boeheim, J. Dabrowiak, J. Zubieta, Inorg. Chim. Acta 216 (1994) 83.
[12] (a) S. Archer, J.A. Weinstein, Coord. Chem. Rev. 256 (2012) 2530;
(b) M.Ya. Mel’nikov, J.A. Weinstein, High Energy Chem. 42 (2008) 287.
[13] (a) S.F. Parker, K. Refson, R.D. Bennett, J. Best, M. Ya, Inorg. Chem. 51 (2012)
9748;
(b) J.A. Weinstein, M.T. Tierney, E.S. Davies, K. Base, A.A. Robeiro, M.W.
Grinstaff, Inorg. Chem. 45 (2006) 4544.
[14] (a) W. Paw, R.J. Lachicotte, R. Eisenberg, Inorg. Chem. 37 (1998) 4139;
(b) S.D. Cummings, L.-T. Cheng, R. Eisenberg, Chem. Mater. 9 (1997) 440;
(c) J.A. Zuleta, J.M. Bevilaqua, J.M. Rehm, R. Eisenberg, Inorg Chem. 31 (1992)
1332;
p
-accepting derivatives dppz (dipyrido[3,2-a:20,30-c]phenazine)
and CF3dppz (11-CF3 substituted) have been investigated and com-
pared with related Pt complexes and the previously reported Pd
derivative [(bpy)Pd(SC6F4H-4)2]. In order to tune the photophysical
and electrochemical properties of such complexes, three parame-
(d) J.A. Zuleta, J.M. Bevilaqua, R. Eisenberg, Coord. Chem. Rev. 111 (1991) 237.
[15] (a) V.W.W. Yam, R.P.L. Tang, K.M.C. Wong, C.C. Ko, K.K. Cheung, Inorg. Chem.
40 (2001) 571;
(b) B.C. Tzeng, W.F. Fu, C.-M. Che, H.Y. Chao, K.K. Cheung, S.M. Peng, J. Chem.
Soc., Dalton Trans. (1999) 1017.
ters were thus at hand; (i) better
p-accepting N^N ligands lower

162
V. Lingen et al. / Inorganica Chimica Acta 423 (2014) 152–162
[16] F. Pevny, M. Zabel, R.F. Winter, A.F. Rausch, H. Yersin, F. Tuczek, S. Zális, Chem.
Commun. 47 (2011) 6302.
[17] M. Kato, T. Okamura, H. Yamamoto, N. Ueyama, Inorg. Chem. 44 (2005) 1966.
[18] (a) E.L. Crossley, J.B. Aitken, S. Vogt, H.H. Harris, L.M. Rendina, Angew. Chem.,
Int Ed. 49 (2010) 1231;
(b) P.B. Glover, P.R. Ashton, L.J. Childs, A. Rodger, M. Kercher, R.M. Williams, L.
De Cola, Z. Pikramenou, J. Am. Chem. Soc. 125 (2003) 9918.
[19] B.-C. Tzeng, C.-S. Ding, T.-Y. Chang, C.-C. Hu, G.-H. Lee, Cryst. Eng. Commun. 14
(2012) 8228.
[40] G.T. Morgan, F.H. Burstall, J. Chem. Soc. (1934) 965.
[41] (a) A.L. Sanger, J. Chem. Soc., Dalton Trans. (1977) 1971;
(b) A.D. Westland, J. Chem. Soc. (1965) 3060.
[42] H.C. Clark, L.E. Manzer, J. Organomet. Chem. 59 (1973) 411.
[43] K. Butsch, R. Gust, A. Klein, I. Ott, M. Romanski, Dalton Trans. 39 (2010) 4331.
[44] (a) W. Kaim, Angew. Chem., Int. Ed. Engl. 22 (1983) 171;
(b) W. Kaim, Rev. Chem. Intermed. 8 (1987) 247.
[45] (a) M. Atsumi, L. González, C. Daniel, J. Photochem. Photobiol. A 190 (2007)
310;
[20] (a) H. Kuniyasu, K. Takekawa, F. Yamashita, K. Miyafuji, S. Asano, Y. Takai, A.
Ohtaka, A. Tanaka, K. Sugoh, H. Kurosawa, N. Kambe, Organometallics 27
(2008) 4788;
(b) K.E. Erkkila, D.T. Odomand, J.K. Barton, Chem. Rev. 99 (1999) 2777;
(c) X.-H. Zou, J.L.-N. Xia-Hua, Trends Inorg. Chem. 7 (2001) 99;
(d) A.E. Friedman, J.-C. Chambron, J.-P. Sauvage, N.J. Turro, J.K. Barton, J. Am.
Chem. Soc. 112 (1990) 4960;
(e) D. Villagra, R. López, S.A. Moya, C. Claver, A. Bastero, Organometallics 27
(2008) 1019.
(b) H. Kuniyasu, F. Yamashita, J. Terao, N. Kambe, Angew. Chem., Int. Ed. 46
(2007) 5929;
(c) H. Kuniyasu, F. Yamashita, T. Hirai, J.-H. Ye, S.-I. Fujiwara, N. Kambe,
Organometallics 25 (2006) 566;
[46] N. Hernandez-Gil, W.E. Wentworth, E.C.M. Chen, J. Phys. Chem. 88 (1984)
6181.
[47] G.B. Deacon, P.W. Elliot, A.P. Erven, G. Meyer, Z. Anorg. Allg. Chem. 631 (2005)
843.
[48] J.C. Bailar Jr., H. Itatani, Inorg. Chem. 4 (1965) 1618.
[49] J.H. Price, A.N. Williamson, R.F. Schramm, B.B. Wayland, Inorg. Chem. 11
(1972) 1280.
[50] G.M. Sheldrick, SHELXS-97, Program for the Solution of Crystal Structures,
University of Göttingen, Germany, 1997.
[51] G.M. Sheldrick, SHELXL-97, Program for the Refinement of Crystal Structures,
University of Göttingen, Germany, 1997.
[52] P. Espinet, A.C. Albéniz, J.A. Casares, J.M. Martínez-Ilarduya, Coord. Chem. Rev.
252 (2008) 2180.
(d) T. Kato, H. Kuniyasu, T. Kajiura, Y. Minami, A. Ohtaka, M. Kinomoto, J. Terao,
H. Kurosawa, N. Kambe, Chem. Commun. (2006) 868.
[21] (a) I.P. Beletskaya, V.P. Ananikov, Pure Appl. Chem. 79 (2007) 1041;
(b) J. Forniés-Cámer, A.M. Masdeu-Bultó, C. Claver, C. Tejel, M.A. Ciriano, C.J.
Cardin, Organometallics 21 (2002) 2609;
(c) J.C. Bayón, C. Claver, A.M. Masdeu-Bultó, Coord. Chem. Rev. 193–195 (1999)
73;
(d) J. Forniés-Cámer, A. Aaliti, N. Ruiz, A.M. Masdeu-Bultó, C. Claver, C.J. Cardin,
J. Organomet. Chem. 530 (1997) 199.
[22] (a) V.K. Jain, L.B. Kumbhare, S. Dey, N.D. Ghavale, Phosphorus Sulfur 183
(2008) 1003;
(b) S. Dey, V.K. Jain, Plat. Met. Rev. 48 (2004) 16;
(c) M. Bochmann, Chem. Vap. Depos. 2 (1996) 85.
[53] B. Still, P.G.A. Kumar, J.R. Aldrich-Wright, W.S. Price, Chem. Soc. Rev. 36 (2007)
665.
[23] (a) M. Howe-Grant, S.J. Lippard, Inorg. Synth. 20 (1980) 101;
(b) M. Howe-Grant, K.C. Wu, W.R. Bauer, S.J. Lippard, Biochemistry 15 (1976)
4339.
[24] (a) R.T.C. Brownlee, W.D. McFadyen, M.J. O’Connor, T.J. Rook, I.A.G. Roos, L.P.G.
Wakelin, Magn. Reson. Chem. 25 (1987) 492;
(b) W.D. McFadyen, L.P.G. Wakelin, I.A.G. Roos, V.A. Leopold, J. Med. Chem. 28
(1985) 1113.
[25] (a) A. Zarkadoulas, E. Koutsouri, C.A. Mitsopoulou, Coord. Chem. Rev. 256
(2012) 2424;
[54] (a) A. Klein, A. Lüning, I. Ott, L. Hamel, M. Neugebauer, K. Butsch, V. Lingen, F.
Heinrich, S. Elmas, J. Organomet. Chem. 695 (2010) 1898;
(b) K. Butsch, S. Elmas, N. Sen Gupta, R. Gust, F. Heinrich, A. Klein, Y. von
Mering, M. Neugebauer, I. Ott, M. Schäfer, H. Scherer, T. Schurr,
Organometallics 28 (2009) 3906;
(c) A. Klein, T. Schurr, H. Scherer, N. Sen Gupta, Organometallics 26 (2007) 230;
(d) A. Klein, K.-W. Klinkhammer, T. Scheiring, J. Organomet. Chem. 592 (1999)
128.
(b) J.S. Pap, F.L. Benedito, E. Bothe, E. Bill, S. DeBeer George, T. Weyhermüller, K.
Wieghardt, Inorg. Chem. 46 (2007) 4187;
[55] C.E. Keefer, R.D. Bereman, S.T. Purrington, B.W. Knight, P.D. Boyle, Inorg. Chem.
38 (1999) 2294.
(c) W. Paw, S.C. Cummings, M.A. Mansour, W.B. Connick, D.K. Geiger, R.
Eisenberg, Coord. Chem. Rev. 171 (1998) 125;
[56] M. Hirano, S. Tatesawa, M. Yabukami, Y. Ishihara, Y. Hara, N. Komine, S.
Komiya, Organometallics 30 (2011) 5110.
(d) W.B. Connick, H.B. Gray, J. Am. Chem. Soc. 119 (1997) 11620;
(e) Y. Zhang, K.D. Ley, K.S. Schanze, Inorg. Chem. 35 (1996) 7102.
[26] J.A. Weinstein, N.N. Zheligovskaya, M.Ya. Mel’nikov, F. Hartl, J. Chem. Soc.,
Dalton Trans. (1998) 2459.
[27] J.A. Weinstein, A.J. Blake, E.S. Davies, A.L. Davis, M.W. George, D.C. Grills, I.V.
Lileev, A.M. Maksimov, P. Matousek, M.Y. Mel’nikov, A.W. Parker, V.E.
Platonov, M. Towrie, C. Wilson, N.N. Zheligovskaya, Inorg. Chem. 42 (2003)
7077.
[57] (a) P.G. Waddell, A.M.Z. Slawin, J.D. Woollins, Dalton Trans. 39 (2010) 8620;
(b) D. Gudat, V.K. Jain, A. Klein, T. Schurr, S. Zalis, Eur. J. Inorg. Chem. (2005)
4056;
(c) A.L. Rieger, G.B. Carpenter, P.H. Rieger, Organometallics 12 (1993) 842;
(d) H. Motschi, P.S. Pregosin, L.M. Venanzi, Helv. Chim. Acta 62 (1979) 667;
(e) T.G. Appleton, H.C. Clark, L.E. Manzer, Coord. Chem. Rev. 10 (1973) 335.
[58] (a) T.G. Appleton, J.R. Hall, S.F. Ralph, Inorg. Chem. 24 (1985). 673–677 and
4685–4693;
[28] V.C. Gibson, N.J. Long, C.K. Williams, M. Fontani, P. Zanello, Dalton Trans.
(2003) 3599.
[29] (a) S. Bernès, L. Villanueva, H. Torrens, J. Chem. Crystallogr. 38 (2008) 123;
(b) A. Garcés-Rodríguez, D. Morales-Morales, S. Hernández-Ortega, Acta
Crystallogr., Sect. E 63 (2007) m479;
(b) P.S. Pregosin, H. Omura, L.M. Venanzi, J. Am. Chem. Soc. 95 (1973) 2047.
[59] E. Pizzo, P. Sgarbossa, A. Scarso, R.A. Michelin, G. Strukul, Organometallics 25
(2006) 3056.
[60] A. Klein, T. Schurr, A. Knödler, D. Gudat, K.-W. Klinkhammer, V.K. Jain, S. Zalis,
W. Kaim, Organometallics 24 (2005) 4125.
(c) G. Rivera, S. Bernès, H. Torrens, Polyhedron 26 (2007) 4276.
[30] F. Estudiante-Negrete, R. Redón, S. Hernández-Ortega, R.A. Toscano, D.
Morales-Morales, Inorg. Chim. Acta 360 (2007) 1651.
[31] (a) M.A. Usón, J.M. Llanos, J. Organomet. Chem. 663 (2002) 98;
(b) R. Usón, J. Forniés, M.A. Usón, M. Tomas, M.A. lbanez, J. Chem. Soc., Dalton
Trans. (1994) 401;
(c) R. Usón, J. Forniés, M.A. Usón, S. Herrero, J. Organomet. Chem. 447 (1993)
137.
[32] S.-K. Lee, D.-Y. Noh, Inorg. Chem. Commun. 13 (2010) 183.
[33] M. Corona-Rodríguez, S. Hernández-Ortega, J. Valdés-Martínez, D. Morales-
Morales, Supramol. Chem. 19 (2007) 579.
[61] S.J. Berners-Price, L. Ronconi, P.J. Sadler, Prog. Nucl. Magn. Reson. Spectrosc. 49
(2006) 65.
[62] (a) C.A. Hunter, K.R. Lawson, J. Perkins, C.J. Urch, J. Chem. Soc., Perkin Trans. 2
(2001) 651;
(b) C. Janiak, J. Chem. Soc., Dalton Trans. (2000) 3885.
[63] K. Osakada, T. Hosoda, T. Yamamoto, Bull. Chem. Soc. Jpn. 73 (2000) 923.
[64] (a) S. Otto, Inorg. Chim. Acta 363 (2010) 3316;
(b) Y. Suzaki, K. Osakada, Organometallics 23 (2004) 5081;
(c) D.C. Smith Jr., C.M. Haar, E.D. Stevens, S.P. Nolan, Organometallics 19 (2000)
1427;
(d) R. Wyrwa, W. Poppitz, H. Görls, Z. Anorg. Allg. Chem. 623 (1997) 649.
[65] A. Castellanos, J.J. Garcia, H. Torrens, N. Bailey, C.O. Rodriguez de Barbarin, A.
Gutierrez, F. del Rio, J. Chem. Soc., Dalton Trans. (1994) 2861.
[66] I. Nakanishi, K. Matsumoto, S. Ooi, Acta Crystallogr., Sect. C 47 (1991) 2073.
[67] A. Singhal, V.K. Jain, A. Klein, M. Niemeyer, W. Kaim, Inorg. Chim. Acta 357
(2004) 2134.
[34] R. Usón, M.A. Usón, S. Herrero, L. Rello, Inorg. Chem. 37 (1998) 4437.
[35] (a) E. Martin, B. Toledo, H. Torrens, F.J. Lahoz, P. Terreros, Polyhedron 17 (1998)
4091;
(b) D. Cruz-Garritz, E. Martin, H. Torrens, K.A. Mayoh, A.J. Smith, Transition
Met. Chem. 16 (1991) 236;
(c) D. Cruz-Garritz, E. Martin, H. Torrens, K.A. Mayoh, A.J. Smith, Acta
Crystallogr., Sect. C 46 (1990) 2377.
[36] (a) B. Rivera, H. Torrens, S. Bernès, Acta Crystallogr., Sect. E 62 (2006) m3287;
(b) J. García, E. Martin, D. Morales, H. Torrens, F. del Río, Inorg. Chim. Acta 207
(1993) 93.
[37] G. Rivera, S. Bernès, C. Rodriguez de Barbarin, H. Torrens, Inorg. Chem. 40
(2001) 5575.
[38] V. Lingen, A. Lüning, C. Strauß, I. Pantenburg, G.B. Deacon, A. Klein, G. Meyer,
Eur. J. Inorg. Chem. (2013) 4450.
[68] The Shannon radii differ only by 0.04 Å (Pd > Pt): R.D. Shannon, Acta
Crystallogr., Sect. A 32 (1976) 751-767. For examples see: (a) M.R. Warren,
S.K. Brayshaw, L.E. Hatcher, A.L. Johnson, S. Schiffers, A.J. Warren, S.J. Teat, J.E.
Warren, C.H. Woodall, R.R. Raithby, Dalton Trans. 41 (2012) 13173;
(b) S. Dey, L.B. Kumbhare, V.K. Jain, T. Schurr, W. Kaim, A. Klein, F. Belaj, Eur. J.
Inorg. Chem. (2004) 4510;
(c) K. Herbst, B. Rink, L. Dahlenburg, M. Brorson, Organometallics 20 (2001)
3655.
[69] S. Scarso, M. Colladon, P. Sgarbossa, C. Santo, R.A. Michelin, G. Strukul,
Organometallics 29 (2010) 1487.
[70] J.C. Fuggle, N. Mårtensson, J. Electron Spectrosc. Relat. Phenom. 21 (1980) 275.
[39] (a) V.K. Jain, L. Jain, Coord. Chem. Rev. 254 (2010) 2848;
(b) V.K. Jain, L. Jain, Coord. Chem. Rev. 249 (2005) 3075;
(c) H. Torrens, Coord. Chem. Rev. 196 (2000) 331.