Solid-phase cyclopalladation in S,C,S′-pincer systems: Rising alternative for synthesis in solution

Article abstract of DOI:10.1039/c4dt03477e

In pursuit of a new and simple approach to complex organometallic systems, the possibility of formation of a palladium-carbon bond in the solid state via direct cyclopalladation has been studied toward several S,C,S′-pincer ligands with thione sulfur donors of different nature. It is found that mixtures of the ligand and PdCl₂(NCPh)₂ obtained by the manual grinding of reactants in a mortar efficiently undergo solid-phase cyclometalation upon heating in open test tubes without the addition of a solvent to afford the desired pincer-type products in high yields. In the case of the most active bis(thiocarbamoyl) ligand, solid-phase cyclopalladation proceeds even at room temperature. For the challenging bis(thiophosphoryl) derivative, the preformed non-metallated complexes can be successfully used as a starting material to essentially enhance the yield of the desired pincer complex compared to the conventional synthesis in solution. The solid-phase transformation is followed by IR spectroscopy and SEM analysis. The results obtained show that the suggested solid-phase methodology can serve as a powerful alternative to conventional synthesis of pincer complexes in solution. This journal is

Full text of DOI:10.1039/c4dt03477e

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DOI: 10.1039/C4DT034177E
Solid-phase cyclopalladation in S,C,S'-pincer systems: rising alternative to
synthesis in solution
Diana V. Aleksanyan,*a Zinaida S. Klemenkova,a Andrei A. Vasil’ev,b Arkadii Ya. Gorenberg,c
Yulia V. Nelyubinaa and Vladimir A. Kozlova
aA. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul.
Vavilova 28, Moscow, 119991 Russia; corresponding author: aleksanyan.diana@ineos.ac.ru
bN. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninskii pr. 47,
Moscow, 119991 Russia
cN. N. Semenov Institute of Physical Chemistry, Russian Academy of Sciences, ul. Kosygina 4,
Moscow, 119991 Russia
Abstract: In pursuit of a new simple approach to complex organometallic systems, a possibility
of formation of the palladium–carbon bond in the solid state via direct cyclopalladation has been
studied toward several S,C,S'ꢀpincer ligands with thione sulfur donors of different nature. It is
found that mixtures of the ligand and PdCl2(NCPh)2 obtained by manual grinding of reactants in
a mortar efficiently undergo solidꢀphase cyclometalation upon heating in open test tubes without
addition of a solvent to afford the desired pincerꢀtype products in high yields. In the case of the
most active bis(thiocarbamoyl) ligand, solidꢀphase cyclopalladation proceeds even at room
temperature. For the challenging bis(thiophosphoryl) derivative, the preformed nonꢀmetallated
complexes can be successfully used as a starting material to essentially enhance the yield of
desired pincer complex compared to the conventional synthesis in solution. The solidꢀphase
transformation is followed by IR spectroscopy and SEM analysis. The results obtained show that
the suggested solidꢀphase methodology can serve as a powerful alternative to conventional
synthesis of pincer complexes in solution.
Keywords: cyclometalation, solidꢀphase synthesis, palladium, pincer complexes
Introduction
Pincer complexes having a tridentate monoanionic framework comprise a privileged class of
organometallic compounds, finding extensive application as active (pre)catalysts, optoelectronic
materials, biomarkers, chemosensors.1,2 There are several synthetic approaches which give
access to pincer metallacycles with almost any type of ligands and metals, but all of them were
accomplished only in solution.2 Nowadays, solidꢀphase synthesis has emerged as a powerful tool
in organic, inorganic and coordination chemistry, affording a great diversity of compounds and
functional materials. While numerous transformations involving organometallic species have

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been successfully performed in the solid state,3 only several reports deal with the direct
formation of the metal–carbon bond via thermallyꢀinduced intramolecular cyclometalation of
some preformed coordination complexes leading to monometallacyclic species.4 Recently we
have shown that solidꢀphase cyclopalladation of coordination predecessors can also be
performed in multidentate, pincerꢀtype systems with thiophosphoryl and benzothiazole pendant
arms.5 To our surprise, it was found that mixtures of a ligand and PdCl2(NCPh)2 obtained simply
by manual grinding in a mortar can also be used as starting materials, efficiently undergoing
thermallyꢀinduced cyclometalation.5 However, the reactions required high temperatures (200 C)
and were accompanied by sample degradation, resulting in reduced yields of the desired pincer
products. Therefore, it seemed interesting to investigate whether such a solidꢀphase strategy is
restricted to the particular ligand systems or can become a simple, cheap, efficient, and green
alternative to the conventional synthesis of pincer complexes in solution.
Results and discussion
Since cyclopalladation is the most popular type of cyclometalations6 and palladium derivatives
ranks as the most explored and useful transition metal complexes, we focused our attention, first
of all, on investigation of the scope of solidꢀphase cyclopalladation. In pursuit of new objects, we
turned to S,C,Sꢀpincer ligands with two thione sulfur ancillary donors which would encourage
the formation of strong coordinate bonds with the soft, thiophilic PdII ion. Furthermore, recent
studies showed that bis(thiocarbamoyl) and thiophosphorylꢀthiocarbamoyl ligands readily form
pincer PdII complexes whereas their bis(thio)phosphoryl analogs undergo cyclopalladation only
under forcing conditions and often with low efficiency.7 Therefore, it would be interesting to
compare the reactivity of closely related S,C,S'ꢀpincer ligands bearing thione sulfur donors of
different nature in solution and in the solid state, especially if take into account the remarkable
catalytic activities and luminescence properties of transition metal complexes based on the
related derivatives.8–10 In addition, organosulfur and organothiophosphorus pincer ligands are
stable and can be airꢀhandled, which is particularly important for the suggested solidꢀphase
approach.
A convenient synthetic route to a series of novel S,C,S'ꢀpincer ligands was devised based
on mꢀdiphenylphosphorylaniline (Scheme 1). Thus, thiophosphorylation of this aniline with
Ph2P(S)Cl followed by thionation of the resulting S,Oꢀderivative with the Lawesson reagent
(Scheme 1) afforded unsymmetrical bis(thiophosphoryl) pincer ligand 1. Application of different
carbonyl chlorides instead of Ph2P(S)Cl at the first stage afforded hybrid thiophosphorylꢀ
thiocarbamoyl ligands having planar secondary (2) or sterically hindered tertiary (3) thioamide
unit (Scheme 1). The key aniline, in turn, was readily available from Ph3P=O via nitration and

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subsequent reduction of the nitro group. Unsymmetrical bis(thiocarbamoyl) pincer ligand
(compound 4) was synthesized from mꢀnitrobenzoic acid (Scheme 2).
Scheme 1 Synthesis of S,C,S’ꢀpincer ligands 1–3
Scheme 2 Synthesis of unsymmetrical bis(thiocarbamoyl) pincer ligand 4
In comparative studies on cyclopalladation of ligands 1–4 in solution, it was found that 2–4
readily undergo selective cyclopalladation under action of PdCl2(NCPh)2 at room temperature to
form κ3ꢀS,C,S'ꢀpincer complexes 6–8 in >80% yields (Table 1, entries 2–4); therewith, the
reaction time reduces from 2 days in the case of ligand 4 to 0.5 h in the case of the most
sterically hindered ligand 3. As expected, bis(thiophosphoryl) analog 1 was least active affording
palladacycle 5 only in 34% yield even under optimized conditions (Table 1, entry 1). In this case,
the reaction mixture filtrate contained several complexes of [L·PdCl2] composition (L – ligand)
which we failed to isolate and identify.
Table 1 Cyclopalladation of pincer ligands 1–4 with PdCl2(NCPh)2: solution vs solidꢀphase
studies

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1 4
-
PdCl2(NCPh)2
NHPh
HN
PPh2
S
HN
PPh2
S
N
PPh2
S
HN
Ph2P
Pd
Cl
5
Pd
Pd
Cl
7
Pd
S
S
S
S
S
Ph
Ph
Cl
Cl
6
8
Cyclopalladation in solution
Solid-phase cyclopalladation
Entry Ligand Product
Conditions
Yield, %a Conditions
Yield, %a
MeCN, reflux, 2 h
34
200°C, 15 min
0
1
1
5
CH2Cl2, r.t., 1 day
MeCN, r.t., 0.5 h
CH2Cl2/DMSO, r.t., 2
days
92
95
95–100°C, 5 min
100–110°C, 5 min 100
75–80°C, 5 min
r.t., 2 days
85
2
3
2
3
6
7
75
80
4
4
8
100b
aYields of isolated products; byield estimated by 1H NMR spectroscopy.
Realization of κ3ꢀS,C,S'ꢀcoordination in complexes 5–8 was unambiguously confirmed by
multinuclear NMR and IR spectral data. Their 31P NMR spectra exhibit a noticeable downfield
(in the case of compounds 6 and 7, ꢁδP = 2.6–5.9 ppm) or upfield (in the case of palladacycle 5,
ꢁδP = 0.4–7.8 ppm) shift relative to the signals of the free ligands, indicating the coordination of
1
the thiophosphoryl groups. In the H NMR spectra, the intensities of aromatic proton signals are
reduced by 1H, proving the occurrence of cyclometalation, and the signals of both thiocarbamoyl
(ꢁδH = 0.4–3.7 ppm) and thiophosphorylamine (ꢁδH = 4.1 ppm) NH protons are deshielded upon
complexation. In the 13C NMR spectra of palladium complexes 5 and 6, the signals of the carbon
atom (C2) undergoing C–H activation shows a strong downfield shift (up to ~20 ppm) compared
to the corresponding ligands; the resonances of the other carbon atoms are also indicative of
complex formation. Furthermore, a lower frequency displacement of the P=S bond stretching
vibrations (6–15 cm–1) and absorption bands associated with NHCS moiety (e.g., by 9 cm–1 in
complex 6) along with the higher frequency shift of ν(N–H) (up to 38 cm–1) in the IR spectra of
palladacycles 5–8 compared to the free ligands serve as additional evidence of participation of
ancillary donor groups in coordination. The solidꢀstate structure of complex 6 was also
elucidated by Xꢀray crystallography (Figure 1). Note that the complexes obtained efficiently
promote the Suzuki crossꢀcoupling of aryl bromides with PhB(OH)2, however, not surpassing in
activity some other reported thiophosphorylꢀcontaining hybrid palladacycles (Table S1 in
ESI).10e

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Fig. 1 General view of complex 6 in representation of nonꢀhydrogen atoms via thermal ellipsoids
at 50% probability level.
To study solidꢀphase cyclopalladation in S,C,S'ꢀpincer systems 1–4, firstly homogeneous
mixtures of the corresponding ligand and PdCl2(NCPh)2 obtained by manual grinding in a mortar
were heated in capillaries in a melting point measuring apparatus to define the temperatures
corresponding to intensive release of HCl using litmus paper indicators. In the case of ligand 1,
HCl was not detected, and the sample gradually decomposed to give a black thick solid residue.
In the other cases, the following temperature ranges of HCl liberation were observed: 71–75 (2),
83–85 (3), and 55–68 °C (4). Further experiments were carried out via heating ~50 mg samples
in open test tubes on oil bath at slightly higher temperatures for several min (see Table 2).
According to the 31P NMR monitoring of the resulting residues dissolved in DMSO immediately
before spectrum registration, complexes 6–8 were generated in quantitative yields. Simple
purification procedures afforded these palladacycles in 75–100% yields (see Table 1). No pincerꢀ
type product was observed in the case of bis(thiophosphoryl) derivative 1 even upon heating at
200°C for 15 min. However, when a solid residue obtained by evaporation of the filtrate of a
reaction mixture of ligand 1 and PdCl2(NCPh)2 (presumably representing a mixture of [L·PdCl2]
complexes) was heated at 200°C for 15 min, complex 5 was formed in 87% yield (31P NMR
monitoring) (Scheme 3). This observation suggests that the preliminary ligand coordination can
promote solidꢀphase cyclopalladation, avoiding undesirable degradation pathways.
1. manual grinding in a mortar
2. 200oC, 15 min
PdCl2(NCPh)2
PdCl2(NCPh)2
1
1
+
+
5
87%
200oC, 15 min
MeCN, reflux, 2 h
5
+
[L . PdCl2]
34%
undefined
non-metallated
complexes
Scheme 3 Cyclopalladation of bis(thiophosphoryl) ligand 1

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Interestingly, the activity series of S,C,S'ꢀpincer ligands in the solid state is opposite to that
observed in solution (4 > 2 > 3), with the least sterically hindered bis(thiocarbamoyl) derivative
4 being the most active. This fact seems to be logical given the crucial role of kinetic factors in
the solidꢀphase reactions but obviously needs further investigations.
To our delight, the solidꢀphase cyclopalladation of ligand 4 proceeds even at room
temperature, coming to completion in 2 days. This observation was supported by IR spectral
monitoring (Fig. 2 and Figs S1–S3 in ESI).
Fig. 2 IR spectral monitoring of roomꢀtemperature solidꢀphase cyclopalladation of ligand 4 with
PdCl2(NCPh)2 (reaction times from top to bottom: 30 min, 7 h, 24 h, 27 h, 48 h).
An intriguing point was the effect of a palladium source. Using ligand 3 as a representative
example, we found that monomeric complexes of PdCl2 with loosely bound ligands can be used
as efficient cyclometalating agents in the solid state (Table 2, entries 1, 2). Therewith, the
temperature required for solidꢀphase cyclopalladation in the case of cyclooctadiene derivative
(Table 2, entry 1) featuring cisꢀarrangement of the auxiliary ligand was higher than in the case of
transꢀPdCl2(NCPh)2. Presumably, double S,Sꢀcoordination is a key step in the formation of
pincer palladium complex for this particular ligand system, therefore, cyclopalladation proceeds
easier with transꢀPdCl2(NCPh)2. A simple salt such as palladium chloride exhibited considerably
lower activity, which was attributed to its polymeric structure consisting of infinite chains.
Moreover, ionic K2PdCl4 requiring upon cyclometalation the liberation of two molecules of
potassium chloride also showed very low efficiency. Therefore, solidꢀphase cyclopalladation
strongly depends on the nature of a cyclometalating agent.

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Table 2 Effect of different Pd(II) sources on solidꢀphase cyclopalladation of ligand 3
Entry Pd(II) source Conditions
Yield of
complex 7, %a
100
PdCl2(NCPh)2 100–110°C, 5 min
1
2
3
4
PdCl2(COD)
PdCl2
130–140°C, 15 min 100
160–165°C, 15 min 30
K2PdCl4
170–175°C, 15 min 20
aYields estimated by 31P NMR spectroscopy.
Scanning electron microscopy studies performed for the reaction of ligand 3 with
PdCl2(COD) revealed considerable restructuring upon solidꢀphase cyclopalladation (Fig. 3).
Thus, two different phases can be clearly distinguished in the initial mixture of the reactants at
the magnification degree of 1000 (Fig. 3a): needles were tentatively attributed to ligand 3 and
microcrystalline powder was attributed to PdCl2(COD). The residue obtained after solidꢀphase
synthesis was found to be much more homogeneous: it looks like a sponge at the low
magnification degree (×30, Fig. 3c) and reveals a microcrystalline structure only upon 20000ꢀ
fold increase (Fig. 3d) when the initial mixture shows separate crystals (Fig. 3b).
a
b
c
d
Fig. 3 SEM images of the initial mixture of ligand 3 and PdCl2(COD) (a,b) and sample obtained
after solidꢀphase synthesis (c,d).
Although all the ligands and palladium precursors are stable and do not undergo melting
under conditions utilized for solidꢀphase cyclopalladation (Tables 1 and 2), in some cases, the
formation of a semiꢀmelt was detected, which may be responsible for the high efficiency of the
overall process. Fig. 4 depicts the photographs of the initial mixture of ligand 3 and PdCl2(COD)
(Fig. 4a), a semiꢀmelt corresponding to the intensive release of HCl (Fig. 4b), and the resulting
solidified sample representing almost neat pincer complex 7 (Fig. 4c).

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a
b
c
Fig. 4 Photographs of the initial mixture of ligand 3 and PdCl2(COD) (a, T = 25°C), semiꢀmelt
formed during solidꢀphase reaction (b, T = 130–140°C), and the resulting solid sample
representing almost neat complex 7 (c, T > 140°C).
Conclusions
In summary, we have shown that solidꢀphase cyclopalladation in S,C,S'ꢀpincerꢀtype
systems can be efficiently carried out at elevated or even room temperature using homogenized
mixtures of the ligand and appropriate PdII precursor obtained simply by grinding the reactants in
a mortar. The application of a mixture of preformed coordination complexes as a starting
material in the case of challenging bis(thiophosphoryl) ligand considerably enhanced the overall
yield of the palladacycle. The absence of a solvent at least during synthesis, easy performance,
and high efficiency allow for considering solidꢀ phase cyclopalladation as a powerful alternative
to conventional synthesis of complex organometallic systems in solution. Investigations on the
scope of solidꢀphase cyclometalation using various types of pincer and related multidentate
systems and different metals as well as mechanistic studies of this phenomenon are currently
under way in our laboratory.
Experimental
If not noted otherwise, all manipulations were carried out without taking precautions to exclude
air and moisture. Benzene and THF were distilled over sodium/benzophenone ketyl.
Dichloromethane and acetonitrile were distilled from P2O5. Pyridine was distilled from CaH2.
Unsymmetrical bis(amide) predecessor for ligand 4, 3ꢀ(benzoylamino)ꢀNꢀphenylbenzamide,11
was synthesized starting from 3ꢀnitrobenzoic acid chloride via condensation with aniline
followed by reduction of the nitro group with tin(II) chloride.10d Ph2P(S)Cl12 was obtained
according to the literature procedure. All other chemicals and solvents were used as purchased
without further purification.
NMR spectra were recorded on Bruker Avanceꢀ300 and Bruker Avanceꢀ400 spectrometers,
and the chemical shifts (δ) were internally referenced by the residual solvent signals relative to
tetramethylsilane (1H and 13C) or externally to H3PO4 (31P). The 13C NMR spectra were

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registered using the JMODECHO mode; the signals for the carbon atoms bearing odd and even
numbers of protons have opposite polarities. The numeration for the carbon atoms of the central
benzene ring in descriptions of the spectral data is in agreement with IUPAC nomenclature for
ligand 1. The same principle of numbering was used for description of a solidꢀstate molecular
structure of complex 6 characterized by Xꢀray crystallography.
Column chromatography was carried out using Merck silica gel 60 (230ꢀ400 mesh ASTM).
IR spectra were recorded on a Nicolet MagnaꢀIR750 FTꢀspectrometer, resolution 2 cm–1, 128
scans. The assignment of absorption bands in the IR spectra was made according to ref.13 C, H,
Cl, Pd, and S elemental analyses for complex 8 were carried out according to the method
developed at the A. N. Nesmeyanov Institute of Organoelement Compounds RAS.14 Melting
points were determined with MPA 120 EZꢀMelt Automated Melting Point Apparatus and were
uncorrected.
The surface morphology of a homogeneous mixture of ligand 3 and PdCl2(NCPh)2
obtained by manual grinding in a mortar as well as the surface morphology of the sample derived
after solidꢀphase synthesis were analyzed using a JEOL JSMꢀ7001F scanning electron
microscope at accelerating voltages of 1–1.5 kV without any treatment of the surface.
Syntheses
3-(Diphenylphosphoryl)aniline. A stirred solution of triphenylphosphine oxide (11.12 g, 0.040
mol) and KNO3 (4.25 g, 0.042 mol) in conc. H2SO4 was heated at 50–60 °C for 6 h. After
cooling to room temperature, the reaction mixture was poured onto ice, and the resulting solution
was extracted with chloroform. After separation, the organic layer was dried over anhydrous
Na2SO4 and evaporated to dryness. To a solution of the resulting residue, bearing a mixture of
isomeric (nitrophenyl)(diphenyl)phosphine oxides, in 150 mL of EtOH, SnCl2·2H2O (54.2 g,
0.240 mol) was added. The stirred reaction mixture was refluxed for 6 h, then the solvent was
replaced for EtOAc (150 mL), and the obtained solution was washed with saturated aqueous
solution of Na2CO3. The organic layer was separated and treated with dilute aqueous
hydrochloric acid, then the aqueous phase was made alkaline to pH ~12, and the desired product
was extracted with chloroform. The organic layer was dried over anhydrous Na2SO4 and
evaporated to dryness. The resulting residue was purified by column chromatography to give
5.30 g of the target metaꢀisomer along with 1.30 g of paraꢀisomer (eluent: CHCl3–EtOH (20:1)).
Yield: 41%. 31P{1H} NMR (161.98 MHz, CDCl3): 29.54 ppm. Mp: 160–162 °C (compare with
166 °C in ref.15

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10
N-[3-(Diphenylphosphoryl)phenyl]-P,P-diphenylthiophosphinic amide.
A solution of Ph2P(S)Cl (0.86 g, 3.5 mmol) in 2 mL of benzene was slowly
dropwise added to a solution of 3ꢀ(diphenylphosphoryl)aniline (1.0 g, 3.4
mmol) in 10 mL of dry pyridine at ~10 °C. The resulting reaction mixture
P(O)Ph2
S
NHPPh2
was diluted with 20 mL of benzene and heated at 50 °C under stirring for 11 h. The precipitate
was filtered off, washed with benzene and Et2O to give 1.5 g of the target compound as a white
crystalline solid. Yield: 86%. Mp: 256–259 °C (dec). 31P{1H} NMR (121.49 MHz, (CD3)2SO):
1
25.50 (P(О)Ph2), 49.85 (NHP(S)Ph2). H NMR (300.13 MHz, (CD3)2SO): 7.17–7.65 (m, 20H,
HAr), 7.94 (dd, 4H, oꢀH in P(S)Ph2, 3JHH=7.1 Hz, 3JHP=13.7 Hz), 8.50 (d, 1H, NH, 2JHP=8.7 Hz).
IR (KBr, ν/cm–1): 511(m), 531(m), 540(s), 615(w), 636(w) (P=S), 678(w), 691(s), 710(m),
720(s), 748(m), 785(w), 831(w), 961(w), 996(w), 1103(m), 1119(m), 1161(w), 1181(s) (P=O),
1238(m), 1292(m), 1436(m), 1469(m), 1482(w), 1582(sh, w), 1591(m), 2946(w), 3049(w),
3116(w). Anal. Calcd for C30H25NOP2S: C, 70.72; H, 4.95; N, 2.75. Found: C, 70.59; H, 5.05; N,
2.74%.
N-[3-(Diphenylthiophosphoryl)phenyl]-P,P-diphenylthiophosphinic
P(S)Ph2
amide, 1.
A
mixture of Nꢀ[3ꢀ(diphenylphosphoryl)phenyl]ꢀP,Pꢀ
3
4
2
diphenylthiophosphinic amide (1.3 g, 2.6 mmol) and Lawesson reagent
(0.8 g, 2.0 mmol) in 40 mL of chlorobenzene was refluxed for 16 h. After
S
1
5
NHPPh2
6
cooling to room temperature, the resulting solution was sequentially washed with aqueous
solution of Na2CO3 and water. The organic layer was separated, dried over anhydrous Na2SO4,
and evaporated to dryness. The resulting residue was crystallized from EtOAc–hexane mixture
(1:1) followed by purification by column chromatography (eluent: CH2Cl2–hexane (1:1)) to give
0.8 g of ligand 1 as a white crystalline solid. Yield: 60%. Mp: 200–202 °C (dec.). 31P{1H} NMR
1
(161.98 MHz, CDCl3): δ 43.23 (P(S)Ph2), 52.54 (NHP(S)Ph2) ppm. H NMR (400.13 MHz,
2
3
CDCl3): δ 5.08 (d, 1H, NH, JHP=6.6 Hz), 7.09 (d, 1H, H(C6), JHH=8.2 Hz), 7.18–7.29 (m, 3H,
HAr), 7.35–7.52 (m, 12H, HAr), 7.61 (dd, 4H, oꢀH in P(S)Ph2, 3JHP=13.2 Hz, 3JHH=8.01 Hz), 7.91
3
3
(dd, 4H, oꢀH in NHP(S)Ph2, JHP=13.4 Hz, JHH=7.7 Hz). 13C{1H} NMR (100.61 MHz,
CDCl3/(CD3)2SO): δ 121.07 (d, C4, 2JCP=6.2 Hz), 121.25–121.50 (unresolved m, C2), 123.48 (d,
3
3
C6, JCP=10.8 Hz), 127.51 (d, mꢀC in P(S)Ph2, JCP=12.1 Hz), 127.59 (d, mꢀC in NHP(S)Ph2,
3
3JCP=12.7 Hz), 128.10 (d, C5, JCP=14.3 Hz), 130.50 (s, pꢀC in P(S)Ph2), 130.72 (d, oꢀC in
2
P(S)Ph2, 2JCP=11.4 Hz), 130.89 (s, pꢀC in NHP(S)Ph2), 131.07 (d, oꢀC in NHP(S)Ph2, JCP=10.8
Hz), 131.68 (d, ipsoꢀC in P(S)Ph2, 1JCP=85.1 Hz), 131.88 (d, C3, 1JCP=85.1 Hz), 132.53 (d, ipso-
1
2
C in NHP(S)Ph2, JCP=103.0 Hz), 140.72 (d, C1, JCP=15.0 Hz). IR (KBr, ν/cm–1): 488(m),
509(m), 514(m), 615(w) and 640(s) (both P=S), 690(s), 695(m), 715(s), 719(sh, s), 758(w),

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11
794(w), 852(w), 944(m), 994(w), 1097(sh, m), 1104(m), 1243(w), 1274(w), 1376(m), 1435(m),
1480(sh, m), 1486(m), 1571(sh, w), 1577(sh, w), 1590(m), 3053(w), 3138(w). Anal. Calcd for
C30H25NP2S2: C, 68.55; H, 4.79; N, 2.66. Found: C, 68.71; H, 5.07; N, 2.61%.
N-[3-(Diphenylphosphoryl)phenyl]benzamide. A stirred mixture of 3ꢀ
P(O)Ph2
3
(diphenylphosphoryl)aniline (1.4 g, 4.8 mmol), benzoyl chloride (0.7 g, 5.0
4
5
2
1
O
mmol), and triethylamine (0.7 mL, 5.0 mmol) in 25 mL of benzene was
heated at 50–60 °C for 10 h. The resulting precipitate was filtered off,
NHCPh
6
washed with water, recrystallized from acetone, and dried under vacuum to give 1.5 g of Nꢀ[3ꢀ
(diphenylphosphoryl)phenyl]benzamide as a white crystalline solid. Yield: 69%. Mp: 226–228
1
°C (acetone). 31P{1H} NMR (161.98 MHz, (CD3)2SO): δ 25.65 ppm. H NMR (400.13 MHz,
3
(CD3)2SO): δ 7.31 (dd, 1H, H(C4), JHP=11.4 Hz, 3JHH=7.6 Hz), 7.51–7.60 and 7.63–7.67 (both
3
3
m, 8H+6H, HAr), 7.94 (d, 2H, oꢀH in C(O)Ph, JHH=7.2 Hz), 8.10 (d, 1H, H(C6), JHH=7.9 Hz),
3
8.15 (d, 1H, H(C2), JHP=13.4 Hz), 10.48 (s, 1H, NH). 13C{1H} NMR (75.47 MHz,
2
2
CDCl3/(CD3)2SO (1:1)): δ 121.27 (d, C2, JCP = 11.3 Hz), 121.85 (s, C6), 124.65 (d, C4, JCP
=
9.1 Hz), 125.80 (s, mꢀC in C(O)Ph), 126.33 (s, oꢀC in C(O)Ph), 126.72 (d, mꢀC in P(O)Ph2, 3JCP
= 11.7 Hz), 127.06 (d, C5, 3JCP = 14.1 Hz), 129.65 (d, oꢀC in P(O)Ph2, 2JCP = 9.3 Hz), 129.71 (s,
1
pꢀC in C(O)Ph), 130.12 (s, pꢀC in P(O)Ph2), 130.52 (d, ipsoꢀС in P(O)Ph2, JCP = 100.9 Hz),
1
3
130.82 (d, C3, JCP = 105.1 Hz), 132.69 (s, ipsoꢀC in C(O)Ph), 137.74 (d, C1, JCP = 14.5 Hz),
164.00 (s, C=O). IR (KBr, ν/cm–1): 524(m), 541(s), 693(s), 705(m), 713(m), 723(s), 753(w),
791(w), 893(w), 1100(w), 1121(m), 1182(s) (P=O), 1239(m), 1246(sh, w), 1264(w), 1310(s),
1394(m), 1413(w), 1436(m), 1477(s), 1542(s), 1580(sh, w), 1594(m), 1668(s) (C(O)NH),
3054(w), 3177(w), 3230(w). Anal. Calcd for C25H20NO2P·H3CC(O)CH3: C, 73.83; H, 5.75; N,
3.08. Found: C, 73.91; H, 5.29; N, 3.20%.
N-[3-(Diphenylthiophosphoryl)phenyl]benzenecarbothioamide, 2.
A
P(S)Ph2
3
mixture of Nꢀ[3ꢀ(diphenylphosphoryl)phenyl]benzamide (1.3 g, 3.3 mmol)
and Lawesson reagent (1.7 g, 4.2 mmol) in 15 mL of chlorobenzene was
refluxed for 7 h. After cooling to room temperature, the resulting solution
4
2
S
1
5
NHCPh
6
was diluted with benzene (35 mL) and washed with water, aqueous solution of Na2CO3, and
again with water. The organic layer was separated, dried over anhydrous Na2SO4, and
evaporated to dryness. The resulting residue was crystallized from Et2O and recrystallized from
benzene to give 1.0 g of ligand 2 as a yellow crystalline solid. Yield: 71%. Mp: 190–193 °C
1
(C6H6). 31P{1H} NMR (161.98 MHz, CDCl3): δ 43.04 ppm. H NMR (400.13 MHz, CDCl3): δ
7.40–7.60 (m, 11H, HAr), 7.73–7.78 (m, 6H, HAr), 8.06 (d, 1H, H(C2), 3JHP=13.7 Hz), 8.14 (br s,
1H, H(C6)), 9.09 (br s, 1H, NH). 13C{1H} NMR (100.61 MHz, (CD3)2SO): 127.56 (d, C5,

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12
3JCP=13.1 Hz), 127.63 (s, C6), 127.98 (s, mꢀC in C(S)Ph), 128.51 (s, oꢀC in C(S)Ph), 129.32 (d,
3
2
2
mꢀC in P(S)Ph2, JCP=12.0 Hz), 129.62 (d, C4, JCP=13.4 Hz), 129.66 (d, C2, JCP=10.6 Hz),
131.44 (s, pꢀC in C(S)Ph), 132.26 (d, oꢀC in P(S)Ph2, 2JCP=10.6 Hz), 132.42 (d, pꢀC in P(S)Ph2,
4JCP=2.5 Hz), 132.68 (d, ipsoꢀC in P(S)Ph2, 1JCP=74.5 Hz), 133.30 (d, C3, 1JCP=84.1 Hz), 140.72
(d, C1, 3JCP=15.2 Hz), 142.90 (s, ipsoꢀC in C(S)Ph), 198.62 (s, C=S). IR (KBr, ν/cm–1): 503(m),
517(s), 614(w), 635(s) (P=S), 692(s), 712(s), 717(s), 742(w), 774(w), 789(w), 998(w), 1103(s),
1212(m), 1305(w), 1345(sh, m), 1360(s), 1414(m), 1436(s), 1448(m), 1474(m), 1478(m),
1489(w), 1536(m) (NHCS), 1583(m), 3050(w), 3072(w), 3213(w). Anal. Calcd for C25H20NPS2:
C, 69.90; H, 4.69; N, 3.26. Found: C, 69.77; H, 4.73; N, 3.21%.
4-Chloro-N-[3-(diphenylphosphoryl)phenyl]butanamide.
A
P(O)Ph2
3
2
solution of 4ꢀchlorobutyryl chloride (0.9 g, 6.4 mmol) in 15 mL of
dichloromethane was slowly dropwise added to a stirred mixture
of 3ꢀ(diphenylphosphoryl)aniline (1.9 g, 6.5 mmol) and Et3N (0.9
4
5
O
1
Cl
N
H
6
mL, 6.5 mmol) in 25 mL of CH2Cl2 at 10 °C. The resulting reaction mixture was stirred at r.t. for
12 h and then washed with water, 5% aqueous solution of Na2CO3, and again with water. The
organic layer was separated, dried over anhydrous Na2SO4, and evaporated to dryness. The
resulting residue was crystallized from EtOAc to give 2.5 g of the desired compound as a white
crystalline solid. Yield: 96%. Mp: 189–192 °C (EtOAc). 31P{1H} NMR (121.49 MHz, CDCl3): δ
1
29.83 ppm. H NMR (300.13 MHz, CDCl3): δ 2.01–2.10 (m, 2H, CH2), 2.44 (t, 2H, CH2C(O),
3
3
3
3JHH=7.3 Hz), 3.42 (t, 2H, CH2Cl, JHH=6.4 Hz), 6.99 (dd, 1H, H(C4), JHP=11.5 Hz, JHH=7.7
Hz), 7.37 (dt, 1H, H(C5), 3JHH=7.9 Hz, 4JHP=4.1 Hz), 7.43–7.48 and 7.54–7.58 (both m, 4H+2H,
3
3
3
HAr), 7.64 (dd, 4H, oꢀH in P(O)Ph2, JHP=12.1 Hz, JHH=7.1 Hz), 8.18 (d, 1H, H(C2), JHP=13.2
3
Hz), 8.51 (d, 1H, H(C6), JHH=8.0 Hz), 10.60 (br s, 1H, NH). 13C{1H} NMR (100.61 MHz,
2
CDCl3): δ 28.07 (s, CH2), 34.05 (s, CH2C(O)), 44.51 (s, СH2Сl), 123.24 (d, C2, JCP = 9.2 Hz),
2
3
123.35 (br s, C6), 125.99 (d, C4, JCP = 11.2 Hz), 128.68 (d, mꢀC in P(O)Ph2, JCP = 12.2 Hz),
1
128.98 (d, C5, 3JCP = 14.0 Hz), 131.61 (d, C3, JCP = 105.8 Hz), 131.99 (d, oꢀC in P(O)Ph2, 2JCP
= 10.1 Hz), 132.00 (d, ipsoꢀC in P(O)Ph2, 1JCP = 104.4 Hz), 132.24 (d, pꢀC in P(O)Ph2, 4JCP = 2.0
Hz), 140.49 (d, C1, 3JCP = 13.6 Hz), 171.42 (s, C=O). IR (KBr, ν/cm–1): 501(w), 516(m), 541(s),
697(m), 708(w), 729(m), 752(m), 760(sh, w), 791(w), 974(w), 1080(w), 1098(w), 1122(m),
1176(s) (P=O), 1220(w), 1243(m), 1297(w), 1308(w), 1332(m), 1381(w), 1399(w), 1416(w),
1437(m), 1477(m), 1553(s) (C(O)NH), 1593(m), 1605(m), 1688(s) (C=O), 3051(m), 3124(w),
3181(w), 3249(w). Anal. Calcd for C22H21ClNO2P: C, 66.42; H, 5.32; N, 3.52. Found: C, 66.70;
H, 5.25; N, 3.38%.

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13
1-[3-(Diphenylphosphoryl)phenyl]pyrrolidin-2-one. Potassium tertꢀ
butoxide (0.6 g, 5.4 mmol) was added to a suspension of 4ꢀchloroꢀNꢀ[3ꢀ
(diphenylphosphoryl)phenyl]butanamide (2.1 g, 5.3 mmol) in 15 mL of
abs. THF at 5 °C. The reaction mixture was stirred at r.t. for 1 day. The
solvent was removed under reduced pressure. A solution of the resulting
residue in dichloromethane was washed with water. The organic layer was
P(O)Ph2
3
4
5
2
1
O
N
6
separated, dried over anhydrous Na2SO4, and evaporated to dryness. The resulting residue was
crystallized from EtOAc to give 1.5 g of 1ꢀ[3ꢀ(diphenylphosphoryl)phenyl]pyrrolidinꢀ2ꢀone as a
white crystalline solid. Yield: 79%. Mp: 173–175 °C (EtOAc). 31P{1H} NMR (161.98 MHz,
1
CDCl3): δ 29.00 ppm. H NMR (400.13 MHz, CDCl3): δ 2.12–2.19 (m, 2H, CH2), 2.61 (t, 2H,
3
3
3
CH2C(O), JHH=8.1 Hz), 3.86 (t, 2H, CH2N, JHH=7.0 Hz), 7.38 (dd, 1H, H(C4), JHP=11.8 Hz,
3JHH=7.6 Hz), 7.45–7.51 and 7.55–7.59 (both m, 5H+2H, HAr), 7.69 (dd, 4H, oꢀH in P(O)Ph2,
3
3
4
3JHP=12.0 Hz, JHH=7.6 Hz), 7.82 (dt, 1H, H(C2), JHP=13.3 Hz, JHH=1.3 Hz), 8.10 (dt, 1H,
3
4
H(C6), JHH=8.0 Hz, JHH=1.3 Hz). 13C{1H} NMR (100.61 MHz, CDCl3): δ 17.86 (s, CH2),
2
4
32.66 (s, CH2C(O)), 48.45 (s, СH2N), 122.31 (d, C2, JCP = 11.4 Hz), 123.49 (d, C6, JCP = 2.6
2
3
Hz), 127.69 (d, C4, JCP = 9.6 Hz), 128.53 (d, mꢀC in P(O)Ph2, JCP = 12.3 Hz), 129.04 (d, C5,
2
4
3JCP = 13.3 Hz), 132.03 (d, oꢀC in P(O)Ph2, JCP = 10.0 Hz), 132.04 (d, pꢀC in P(O)Ph2, JCP
=
2.8 Hz), 132.31 (d, ipsoꢀC in P(O)Ph2, 1JCP = 104.5 Hz), 133.17 (d, C3, 1JCP = 103.7 Hz), 139.72
3
(d, C1, JCP = 14.2 Hz), 174.45 (s, C=O). IR (KBr, ν/cm–1): 497(m), 510(m), 541(s), 591(w),
691(m), 700(m), 707(w), 724(s), 754(m), 759(m), 797(w), 1084(w), 1108(m), 1119(m), 1195(s)
(P=O), 1221(w), 1275(w), 1290(w), 1326(m), 1388(s), 1426(w), 1434(m), 1443(w), 1476(m),
1485(m), 1570(w), 1592(m), 1694(s) (C=O), 2883(w), 2947(w), 2981(w), 3076(w). Anal. Calcd
for C22H20NO2P: C, 73.12; H, 5.58; N, 3.88. Found: C, 73.09; H, 5.64; N, 3.78%.
1-[3-(Diphenylthiophosphoryl)phenyl]pyrrolidine-2-thione,
3.
A
P(S)Ph2
3
2
mixture of 1ꢀ[3ꢀ(diphenylphosphoryl)phenyl]pyrrolidinꢀ2ꢀone (1.0 g, 2.8
mmol) and Lawesson reagent (1.2 g, 3.0 mmol) in 20 mL of toluene was
refluxed for 5 h. After cooling to room temperature, the resulting solution
was poured into water. The organic layer was separated, and the aqueous
4
5
S
1
N
6
phase was extracted additionally with chloroform. The combined organic fraction was washed
with 5% aqueous solution of Na2CO3 and water. The organic layer was separated, dried over
anhydrous Na2SO4, and evaporated to dryness. The resulting crystalline residue was
recrystallized from benzene–diethyl ether to give 0.8 g of ligand 3 as a pale yellow crystalline
solid. Yield: 73%. Mp: 157–159 °C (C6H6/Et2O (1:2)). 31P{1H} NMR (161.98 MHz, CDCl3): δ
1
42.99 ppm. H NMR (400.13 MHz, CDCl3): δ 2.15–2.22 (m, 2H, CH2), 3.18 (t, 2H, CH2C(S),

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14
3
3JHH=7.8 Hz), 4.10 (t, 2H, CH2N, JHH=7.2 Hz), 7.42–7.54 (m, 7H, HAr), 7.63 (dt, 1H, H(C4),
3
3
3JHP=12.7 Hz, JHH=7.8 Hz), 7.73–7.80 (m, 5H, HAr), 7.96 (dt, 1H, H(C2), JHP=14.0 Hz,
4JHH=1.8 Hz). 13C{1H} NMR (100.61 MHz, CDCl3): δ 20.57 (s, CH2), 46.48 (s, CH2C(S)), 58.12
4
2
(s, СH2N), 127.55 (d, C6, JCP = 2.7 Hz), 128.63 (d, C2, JCP = 12.2 Hz), 128.66 (d, mꢀC in
3
2
P(S)Ph2, 3JCP = 12.7 Hz), 129.24 (d, C5, JCP = 13.6 Hz), 130.94 (d, C4, JCP = 10.3 Hz), 131.78
(d, pꢀC in P(S)Ph2, 4JCP = 2.8 Hz), 132.28 (d, ipsoꢀC in P(S)Ph2, 1JCP = 85.7 Hz), 132.32 (d, oꢀC
2
1
3
in P(S)Ph2, JCP = 10.8 Hz), 134.22 (d, C3, JCP = 84.5 Hz), 140.56 (d, C1, JCP = 14.8 Hz),
203.32 (s, C=S). IR (KBr, ν/cm–1): 509(m), 517(s), 592(w), 615(w), 642(m) (P=S), 670(w),
692(s), 716(s), 744(w), 753(m), 797(w), 997(w), 1073(w), 1102(m), 1144(m), 1257(m), 1296(s),
1311(m), 1415(s), 1436(s), 1455(w), 1478(m), 1487(s), 1571(w), 1592(w), 2920(w), 2985(w),
3044(w). Anal. Calcd for C22H20NPS2: C, 67.15; H, 5.12; N, 3.56. Found: C, 67.19; H, 5.08; N,
3.42%.
N-Phenyl-3-[(phenylthiocarbonyl)amino]benzenecarbothioamide, 4. A
C(S)NHPh
3
mixture of 3ꢀ(benzoylamino)ꢀNꢀphenylbenzamide (1.2 g, 3.8 mmol) and
4
5
2
1
S
Lawesson reagent (2.0 g, 5 mmol) in 40 mL of toluene was refluxed for 6 h.
The resulting precipitate was filtered off, dissolved in EtOAc. The solution
NHCPh
6
obtained was washed with saturated aqueous solution of NaHCO3 and water. The organic layer
was separated, dried over anhydrous Na2SO4, and evaporated to dryness. The resulting residue
was purified by column chromatography (eluent EtOAc–hexane (3:1)) to give 0.25 g of ligand 4
1
as a lemon yellow crystalline solid. Yield: 19%. Mp: 194–196 °C. H NMR (400.13 MHz,
3
(CD3)2SO): 7.29 (m, 1H, H(C5)), 7.44–7.56 (m, 6H, HAr), 7.70 (d, 1H, H(C4), JHH=7.5 Hz),
3
7.82–7.87 (m, 4H, HAr), 8.03 (d, 1H, H(C6), JHH=7.8 Hz), 8.29 (s, 1H, H(C2)), 11.86 (br s, 1H,
NH), 11.92 (br s, 1H NH). 13C{1H} NMR (100.61 MHz, (CD3)2SO): 124.33 (s, C2), 124.59 (s,
oꢀC in NHPh), 125.08 (s, C3), 126.82 and 126.92 (both s, C6 and pꢀC in NHPh), 127.95 (s, oꢀC
in C(S)Ph), 128.56 (s, mꢀC in NHPh or C(S)Ph), 128.63 (s, C5), 129.02 (s, mꢀC in NHPh or
C(S)Ph), 131.40 (s, pꢀC in C(S)Ph), 140.18 and 140.44 (both s, C1 and ipsoꢀC in NHPh), 142.95
and 143.46 (both s, C3 and ipsoꢀC in C(S)Ph), 197.22 and 198.52 (both s, C=S). IR (KBr, ν/cm–
1): 693(s), 705(vs), 769(w), 809(w), 866(w), 991(w), 1037(m), 1078(w), 1158(w), 1192(m),
1221(m), 1240(w), 1264(w), 1310(w), 1360(sh, s), 1372(s), 1414(w), 1447(m), 1485(m),
1491(m), 1521(s) and 1536(s) (both NHCS), 1593(sh, w), 1598(w), 2864(w), 2959(m), 3039(m),
3125(br, m) and 3178(br, m) (both NH). Anal. Calcd for C20H16N2S2: C, 68.93; H, 4.63; N, 8.04;
S, 18.40. Found: C, 68.94; H, 4.66; N, 8.01; S, 18.79%.

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{2-(Diphenylthiophosphoryl)-6-
5
[(diphenylthiophosphoryl)amino]phenyl}palladium chloride, 5. A
solution of PdCl2(NCPh)2 (37 mg, 0.096 mmol) and ligand 1 (51 mg,
0.097 mmol) in 7.5 mL of acetonitrile was refluxed for 2 h. The
desired product was collected by filtration, washed with MeCN (5 mL)
4
3
6
1
HN
PPh2
S
2
Ph2P
Pd
S
Cl
and Et2O (5 mL), and recrystallized from DMSO–EtOH (1:2) to give 22 mg of complex 5 as a
pale yellow crystalline solid. Yield: 34%. Mp: >250 °C (dec.). 31P{1H} NMR (121.49 MHz,
1
(CD3)2SO): δ 42.80 (P(S)Ph2), 44.71 (NHP(S)Ph2) ppm. H NMR (300.13 MHz, (CD3)2SO): δ
3
7.09 (ddd, 1H, H(C4), JHP=11.6 Hz, 3JHH=6.5 Hz, 4JHH=2.6), 6.95–7.04 (m, 2H, HAr), 7.64–7.75
3
3
(m, 16H, HAr), 7.89 (dd, 4H, oꢀH in P(S)Ph2, JHP=14.2 Hz, JHH=7.1 Hz), 9.13 (d, 1H, NH,
2
2JHP=9.2 Hz). 13C{1H} NMR (100.61 MHz, (CD3)2SO): δ 121.97 (d, C4, JCP=10.3 Hz), 125.18
3
3
3
(d, C5, JCP=16.9 Hz), 125.34 (d, C6, JCP=15.4 Hz), 129.07 (d, mꢀC in P(S)Ph2, JCP=13.2 Hz),
129.41 (d, mꢀC in NHP(S)Ph2, 3JCP=11.7 Hz), 129.91 (d, C3, 1JCP=82.5 Hz), 130.86 (d, ipsoꢀC in
1
2
P(S)Ph2, JCP=101.2 Hz), 131.82 (d, oꢀC in P(S)Ph2, JCP=11.7 Hz), 132.24 (d, oꢀC in
2
NHP(S)Ph2, JCP=11.0 Hz), 133.19 (s, pꢀC both in P(S)Ph2 and NHP(S)Ph2), 141.40–142.13
2
1
(unresolved m, C2), 143.44 (d, C1, JCP=20.5 Hz), 146.87 (d, ipso-C in NHP(S)Ph2, JCP=104.9
Hz). IR (KBr, ν/cm–1): 510(s), 523(w), 609(m) and 626(m) (both P=S), 688(s), 710(s), 721(s),
745(m), 781(w), 966(br, w), 998(w), 1106(s), 1109(sh, m), 1153(w), 1181(w), 1220(w),
1271(w), 1277(w), 1364(m), 1437(s), 1460(w), 1483(w), 1561(w), 1573(w), 1586(w), 2812(w),
2889(w), 2999(w), 3051(m), 3091(m). Anal. Calcd for C30H24ClNP2PdS2: C, 54.06; H, 3.63; N,
2.10. Found: C, 53.71; H, 3.67; N, 2.11%.
{2-(Diphenylthiophosphoryl)-6-
5
4
[(phenylthiocarbonyl)amino]phenyl}palladium chloride, 6.
A
6
3
solution of PdCl2(NCPh)2 (25 mg, 0.065 mmol) in 2 mL of CH2Cl2 was
slowly dropwise added to a solution of ligand 2 (28 mg, 0.065 mmol) in
3 mL of dichloromethane. The resulting reaction mixture was left under
1
HN
PPh2
S
2
PhC
Pd
S
Cl
ambient conditions for 24 h. The desired product was collected by filtration, washed with
CH2Cl2 (10 mL) and Et2O (5 mL), and dried in vacuo to give 34 mg of complex 6 as a yellow
crystalline solid. Yield: 92%. Mp: >185 °C (dec.). 31P{1H} NMR (161.98 MHz, (CD3)2SO): δ
1
3
48.95 ppm. H NMR (400.13 MHz, (CD3)2SO): δ 6.98 (dd, 1H, H(C4), JHP=11.8 Hz, 3JHH=7.6
3
4
Hz), 7.34 (dt, 1H, H(C5), JHH=7.8 Hz, JHP=4.6 Hz), 7.58–7.61 (m, 2H, mꢀH in C(S)Ph), 7.68–
3
7.72 and 7.74–7.78 (both m, 7H+5H, HAr), 7.87 (d, 2H, oꢀH in C(S)Ph, JHH=7.9 Hz), 12.83 (br
3
s, 1H, NH). 13C{1H} NMR (75.47 MHz, (CD3)2SO): δ 125.74 (d, C5, JCP=14.8 Hz), 126.10 (s,

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C6), 128.55 (s, mꢀC in C(S)Ph), 129.03 (s, oꢀC in C(S)Ph), 129.76 (d, mꢀC in P(S)Ph2, 3JCP=12.6
1
2
Hz), 129.88 (d, ipsoꢀC in P(S)Ph2, JCP=80.1 Hz), 130.12 (d, C4, JCP=16.5 Hz), 132.40 (d, oꢀC
in P(S)Ph2, 2JCP=11.0 Hz), 132.47 (s, pꢀC in C(S)Ph), 133.55 (d, pꢀC in P(S)Ph2), 136.63 (s, ipsoꢀ
3
2
C in C(S)Ph), 138.41 (d, C1, JCP=20.3 Hz), 144.22 (d, C2, JCP=26.3 Hz), 150.28 (d, C3,
1JCP=108.1 Hz), 176.64 (s, C=S). IR (KBr, ν/cm–1): 515(s), 611(w), 626(m) (P=S), 687(s),
708(s), 719(m), 736(sh, m), 749(m), 793(m), 889(w), 999(m), 1025(w), 1034(w), 1070(w),
1105(s), 1154(w), 1184(m), 1197(w), 1246(w), 1307(w), 1379(m), 1407(m), 1436(s), 1453(m),
1479(w), 1492(w), 1525(m), 1575(sh, m), 1585(m), 3055(m), 3149(w), 3227(m). Anal. Calcd for
C25H19ClNPPdS2: C, 52.64; H, 3.36; N, 2.46. Found: C, 52.52; H, 3.25; N, 2.75.
[2-(Diphenylthiophosphoryl)-6-(2-thioxopyrrolidin-1-
5
4
3
6
yl)]palladium chloride, 7. A solution of PdCl2(NCPh)2 (31 mg,
0.081 mmol) in 4 mL of acetonitrile was slowly dropwise added to a
solution of ligand 3 (32 mg, 0.081 mmol) in 4 mL of MeCN. In 30
min, the desired product was collected by filtration, washed with
1
N
PPh2
S
2
Pd
S
Cl
MeCN (5 mL) and Et2O (10 mL), and dried in vacuo to give 41 mg of complex 7 as a light
yellow crystalline solid. Yield: 95%. Mp: >200 °C (dec.). 31P{1H} NMR (161.98 MHz,
(CD3)2SO): δ 45.55 ppm. 1H NMR (400.13 MHz, (CD3)2SO): δ 2.25–2.34 (m, 2H, CH2), 3.26 (t,
3
3
3
2H, CH2C(S), JHH=7.6 Hz), 4.50 (t, 2H, CH2N, JHH=6.9 Hz), 6.95 (dd, 1H, H(C4), JHP=11.9
3
Hz, 3JHH=7.3 Hz), 7.30–7.36 (m, 1H, H(C5)), 7.58 (d, 1H, H(C6), JHH=8.4 Hz), 7.65–7.78 (m,
10H, HAr). IR (KBr, ν/cmꢀ1): 509(m), 528(w), 551(w), 598(w), 612(m) and 627(s) (both P=S),
690(s), 706(s), 720(m), 746(sh, m), 749(m), 783(w), 998(w), 1106(s), 1162(w), 1188(w),
1266(w), 1311(s), 1385(m), 1417(w), 1436(s), 1460(m), 1484(m), 1490(m), 1557(w), 1562(w),
2987(w), 3051(w). Anal. Calcd for C22H19ClNPPdS2: C, 49.45; H, 3.58; N, 2.62. Found: C,
49.27; H, 3.54; N, 2.73%.
{2-(Anilinothiocarbonyl)-6-
5
6
4
3
[(phenylthiocarbonyl)amino]phenyl}palladium chloride, 8. A
solution of PdCl2(NCPh)2 (46 mg, 0.120 mmol) in 7 mL of CH2Cl2
was slowly dropwise added to a solution of ligand 4 (42 mg, 0.121
mmol) in 0.5 mL of DMSO. The resulting reaction mixture was left
1
HN
CNHPh
S
2
PhC
Pd
S
Cl
under ambient conditions for 2 d. The desired product was collected by filtration, washed with
CH2Cl2 (10 mL) and Et2O (5 mL), and dried in vacuo to give 47 mg of complex 8 as a yellow
1
crystalline solid. Yield: 80%. Mp: >230 °C (dec.) H NMR (400.13 MHz, (CD3)2SO): 7.42 (t,
3
1H, HAr, JHH=8.0 Hz), 7.45–7.49 (m, 1H, HAr), 7.56–7.61 (m, 6H, HAr), 7.68 (t, 1H, pꢀH in
3
3
C(S)NHPh, JHH=7.4 Hz), 7.83 (d, 1H, H(C4), JHH=7.9 Hz), 7.88 (d, 2H, oꢀH in C(S)NHPh,

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17
3
3JHH=7.3 Hz), 8.00 (d, 1H, H(C6), JHH=7.3 Hz), 12.25 and 12.65 (both br s, 1H+1H, NH). IR
(KBr, ν/cm–1): 688(m), 690(sh, m), 708(m), 712(sh, m), 739(m), 760(w), 767(w), 802(w),
811(w), 984(w), 1027(w), 1051(w), 1182(w), 1196(w), 1259(m), 1263(m), 1306(w), 1310(w),
1322(w), 1369(w), 1406(m), 1421(m), 1443(s), 1451(s), 1494(m), 1531(s), 1579(m), 1595(m),
3044(m), 3098(w), 3158(w) and 3216(m) (both NH). Anal. Calcd for C20H15ClN2PdS2: C, 49.09;
H, 3.09; Cl, 7.24; N, 5.72; Pd, 21.75; S, 13.11. Found: C, 49.08; H, 3.09; Cl, 7.25; N, 5.64%; Pd,
21.89; S, 13.08%.
General procedure for the solid-phase synthesis of complexes 6–8. A mixture of the
corresponding ligand and PdCl2(NCPh)2 (ca 50 mg), obtained by manual grinding of the
reactants in a mortar for several minutes, was heated at specified temperature (see Table 1) (oil
bath) for 5 min to give the desired pincerꢀtype products in quantitative yields as it was estimated
1
by 31P or H NMR spectroscopy. In the case of ligand 3, the resulting light yellow solid residue
was rinsed with Et2O (10 mL) and dried in air to give complex 7 in a quantitative yield. In the
case of ligands 2 and 4, the resulting brown (2) or orange (4) residue was dissolved in a DMSO–
CH2Cl2 mixture (1:15, 30 mL) and filtered through a pad of cotton. After removal of
dichloromethane, complexes 6 and 8 were precipitated with Et2O. Note that complex 8 was
obtained as a crystallosolvate with DMSO (Anal. Calcd for C20H15ClN2PdS2·2DMSO: C, 44.65;
H, 4.22; N, 4.34. Found: C, 44.64; H, 4.32; N, 4.38%).
Crystal structure determination and data collection. Crystals of complex
6
(C25H19ClNPPdS2, M = 570.35), which were obtained by slow diffusion of ethanol into DMSO
solution of 6, are monoclinic, space group P21/c, at 100K: a = 12.9875(5), b = 13.4110(5), c =
13.5738(5) Å, β = 110.7650(10)°, V = 2210.65(14) Å3, Z = 4 (Z’ = 1), dcalc = 1.714 gcm–3,
ꢀ(MoKα) = 12.36 сmꢀ1, F(000) = 1144. Intensities of 25908 reflections were measured with a
Bruker SMART APEX2 CCD diffractometer [λ(MoKα) = 0.71072Å, ωꢀscans, 2θ<58°], and
5867 independent reflections [Rint = 0.0385] were used in further refinement. The structure was
solved by the direct method and refined by the fullꢀmatrix leastꢀsquares technique against F2 in
the anisotropicꢀisotropic approximation. The hydrogen atom of the NH group was located from
the Fourier density synthesis and refined in isotropic approximation. The H(C) atom positions
were calculated. All hydrogen atoms were refined in the isotropic approximation in riding model
with the Uiso(H) parameters equal to 1.2 Ueq(Xi), where U(Xi) are the equivalent thermal
parameters of the parent atoms to which the corresponding H atoms are bonded. For compound 6
the refinement converged to wR2 = 0.0628 and GOF = 1.002 for all independent reflections (R1
= 0.0250 was calculated against F for 5017 observed reflections with I>2σ(I)). All calculations
were performed using SHELXTL PLUS 5.0.

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18
CCDC 971436 contains the supplementary crystallographic data for 6. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the
Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44)
1223ꢀ336ꢀ033; or eꢀmail: deposit@ccdc.cam.ac.uk.
Acknowledgements
This work was supported by the Russian Foundation for Basic Research, project no. 14ꢀ03ꢀ
31237ꢀmolꢀa. SEM studies were performed using the equipment of MIPT Center of Collective
Use (CCU) with the financial support from the Ministry of Education and Science of the Russian
Federation.
Electronic supplementary information
Electronic supplementary information (ESI) available: IR spectra of ligand 4 and complex 8; IR
spectral monitoring of solidꢀphase cyclopalladation of ligand 4; catalytic performance of
complexes 5–8 in the Suzuki crossꢀcoupling.
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Cyclopalladation of pincer ligands can proceed efficiently in the solid state, serving as a
powerful alternative to synthesis in solution.