Gold and platinum benzenehexathiolate complexes as large templates for the synthesis of 12-coordinate polyphosphine macrocycles

Article abstract of DOI:10.1016/S0020-1693(99)00552-6

A general strategy for the synthesis of large-ring, poly-donor macrocycles using multi-metal ion templates is outlined. This strategy is illustrated in the design and synthesis of the hexanuclear (divinyl)(phenyl)phosphine gold complex of benzenehexathiolate, {[(C₂H₃)₂(Ph)P]Au}₆(C₆S₆) (1), which undergoes macrocycle formation upon reaction with PhPH₂ in the presence of AIBN (Scheme 1). NMR spectra (¹H and ³¹P) and elemental analyses indicate that the resulting macrocycle is a 36-membered ring containing 12 phosphorus donors, six of which are coordinated to the six Au atoms in the Au₆(C₆S₆) core. A series of tri-platinum complexes, [(P(intersection set)P)Pt]₃(C₆S₆) (16-19), where (P(intersection set)P) is a bidentate phosphine ligand, with three (P(intersection set)P)Pt¹¹ units coordinated to a C₆S₆/^6- core, were also prepared as models for templated formation of other poly-phosphorus macrocycles. (C) 2000 Elsevier Science S.A.

Full text of DOI:10.1016/S0020-1693(99)00552-6

www.elsevier.nl/locate/ica
Inorganica Chimica Acta 300–302 (2000) 273–279
Gold and platinum benzenehexathiolate complexes as large
templates for the synthesis of 12-coordinate polyphosphine
macrocycles
Jennifer A. Harnisch, Robert J. Angelici *
Ames Laboratory and Department of Chemistry, Iowa State Uni6ersity Ames, IA 50011, USA
Received 2 September 1999; accepted 1 December 1999
Abstract
A general strategy for the synthesis of large-ring, poly-donor macrocycles using multi-metal ion templates is outlined. This
strategy is illustrated in the design and synthesis of the hexanuclear (divinyl)(phenyl)phosphine gold complex of benzenehexa-
thiolate, {[(C2H3)2(Ph)P]Au}6(C6S6) (1), which undergoes macrocycle formation upon reaction with PhPH2 in the presence of
AIBN (Scheme 1). NMR spectra (1H and 31P) and elemental analyses indicate that the resulting macrocycle is a 36-membered ring
containing 12 phosphorus donors, six of which are coordinated to the six Au atoms in the Au6(C6S6) core. A series of tri-platinum
complexes, [(PSP)Pt]3(C6S6) (16–19), where (PSP) is a bidentate phosphine ligand, with three (PSP)PtII units coordinated to a
6−
C6S6
core, were also prepared as models for templated formation of other poly-phosphorus macrocycles. © 2000 Elsevier
Science S.A. All rights reserved.
Keywords: Benzenehexathiolate complexes; Templated synthesis; Phosphine macrocycle; Gold complexes; Platinum complexes
1. Introduction
metal ion templates is limited by the size of this metal
ion [18,19].
Since Pederson’s [1] discovery of crown ethers in
1967, much research has been dedicated to the develop-
ment of other cyclic ligands with cation-specific binding
abilities. Through the years exceedingly complex
macrocycles have been prepared, which include donor
atoms other than oxygen; these include nitrogen, sulfur,
phosphorus and arsenic [2–8].
Generally, methods for the preparations of large ring
compounds (containing more than six heteroatoms) are
highly inefficient with the success depending strongly
on the preorganization of reactants prior to macrocycle
assembly. Preorganization is often accomplished by
using metal ions as templates [9,10]. In many cases, the
size of the metal ion template controls the number of
heteroatoms and size of the resulting macrocycle [11–
17]. Since Cs+ is the largest non-radioactive metal ion,
the size of macrocycles that can be prepared using
In this paper, we initiate studies of the design of
templates containing several metal ions that will permit
the synthesis of much larger macrocycles. Although
many designs for such templates can be conceived, Fig.
1 illustrates a template that is based on a benzene core
with donor atoms (X) that bind to six metal ions (M).
These metal ions serve as sites at which macrocycle
precursors with donor groups (A) can be organized
prior to linking to give the macrocycle in Fig. 1. As
illustrated in this Figure, the resulting macrocycle has
12 donor atoms (A); however, one can imagine that
different numbers of donor atoms (A) could be incor-
porated depending on the coordination numbers and
geometries of the metal ions (M). In principle, the
donor atoms (A) could be O, S, N, P and other typical
ligand atoms.
Although there are numerous reports of macrocycles
in the literature [2–8], comparatively few phosphine
macrocycles are among them [20–44], and there are no
examples of phosphacrowns that have more than four
* Corresponding author. Tel.: 1-515-294 6342; fax: +1-515-294
0105.
E-mail address: angelici@iastate.edu (R.J. Angelici)
0020-1693/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0020-1693(99)00552-6

274
J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
Fig. 2. Schmidbaur’s ‘golden wheel’ [49].
cycles, our approach was to make the (divinyl)-
(phenyl)phosphine analog of the ‘golden wheel’ and then
link the neighboring vinyl groups with PhPH2 as shown
in Scheme 1. Free-radical addition of PꢀH bonds across
alkenes has been used to prepare several tri- [25–27]
and tetradentate [32] phosphine macrocycles; Norman
and co-workers first used this approach to prepare
Fig. 1. Generalized strategy for the synthesis of large macrocycles
around a template consisting of six metal ions (M).
phosphorus atoms in the ring. This is surprising since
acyclic phosphines form numerous transition metal com-
plexes, many of which are homogeneous catalysts [45–
48]. Complexes with multidentate phosphacrowns
containing more than four phosphorus atoms might be
expected to give complexes with unusual structures and
catalytic activities. Several of the known tri- and tetra-
dentate phosphacrowns were prepared using transition
metal templates to control the synthetic outcome
[20,21,25,28,31,32]. However, as noted above, the use of
a single metal ion template limits the size of the phos-
phine macrocycle that can be synthesized.
fac-(CO)3Mo(PHC3H6)3
[25]
by
heating
fac-
(CO)3Mo(H2PCH2CHꢁCH2)3 in the presence of AIBN.
In our second approach to the synthesis of a polyphos-
phine macrocycle, we again made use of the C6S66− core,
but incorporated three square-planar Pt(II) ions, which
also bind to bidentate phosphine ligands with PꢀH
groups at each phosphorus donor (Scheme 2). Molecular
models indicate that these PꢀH groups, when reacted
with (divinyl)(phenyl)phosphine, (C2H3)2(Ph)P, using an
AIBN catalyst [50], should give a stable 30-atom macro-
cycle ring with nine phosphorus donor groups.
Our approach to the synthesis of polyphosphine lig-
ands uses benzenehexathiolate (C6S66−) as the arene
core of the multi-metal ion template in the structure in
Fig. 1. Schmidbaur and co-workers [49] showed that
In this paper, we describe syntheses of the Au and Pt
templates {[(C2H3)2(Ph)P]Au}6(C6S6) (1) and [(PSP)Pt]3-
(C6S6) and the use of 1 in the subsequent cyclization
reaction described in Scheme 1.
6−
C6S6 forms a ‘golden wheel’ (Fig. 2) when 6 equiv. of
(Ph3P)AuCl react with benzenehexathiol and triethyl-
amine in chloroform. The X-ray-determined structure of
the hexanuclear (triphenylphosphine)gold benzene-
hexathiolate compound, [(Ph3P)Au]6(C6S6), shows that
the arene carbon, sulfur, Au, and P atoms are nearly
co-planar with a slight puckering of the sulfur and gold
hexagons.
2. Experimental
2.1. Materials and methods
All preparative reactions and manipulations were
carried out under an atmosphere of N2 or Ar using
For the synthesis of 12-coordinate phosphine macro-
Scheme 1. Cyclization reaction of template (1) with PhPH2 to produce templated macrocycle 2.

J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
275
Scheme 2. Cyclization reaction of 3 with (divinyl)(phenyl)phosphine.
standard Schlenk techniques [51]. Anhydrous platin-
um dichloride, cis-dichlorobis(triphenylphosphine)plati-
num(II), 1,2-bis(dimethylphosphino)ethane (dmpe), 1,3-
bis(phenylphosphino)propane (ppp), and phenylphos-
phine were purchased from Strem Chemical Co.,
Newburyport, MA. All other materials were purchased
from Aldrich Chemical Co., Milwaukee, WI. Benzene-
hexathiol was prepared using a literature procedure
[49,52] modified as described below. Solvents were
purified under nitrogen using standard methods [53].
Dichloromethane, benzene, hexanes, and ethyl sulfide
were refluxed over CaH2 and then distilled. THF was
distilled from sodium benzophenone. CD2Cl2, CDCl3,
for these species: l 3.06 (q) and l 1.39 (t) for the
Et3NH+ cation, l 5.30 (s) for CH2Cl2 and l 1.56 (s) for
H2O.
2.2. Preparation of benzenehexathiol, C6(SH)6
2.2.1. Synthesis of hexakis(benzylthio)benzene,
C6(SCH2Ph)6 (5)
In an atmosphere of nitrogen, 4.8 g (120 mmol) of a
60% NaH suspension in mineral oil was washed with
dry hexanes 3×10 ml, followed by 2×10 ml of DMF.
Then 50 ml of DMF was added to the flask. The
suspension was cooled to 0°C and 14.1 ml (120 mmol)
of benzyl mercaptan was slowly added to avoid foam-
ing. Then 2.85 g (10 mmol) of C6Cl6 was added in three
portions. The reaction was stirred for 10 min at 0°C
and allowed to warm to room temperature (r.t.). The
mixture congealed and was left under N2. After 1 h the
solvent was removed under reduced pressure leaving
behind a yellow residue, which was dissolved in chloro-
,
CD3CN and CD3OD were stored over 4 A molecular
sieves under nitrogen.
1H and 13C NMR spectra were recorded on a Varian
VXR 300 MHz spectrometer using the residual solvent
peak as an internal reference (1H NMR: l 5.32
(CD2Cl2), 7.26 (CDCl3), 1.94 (CD3CN), 4.78 (CD3OD);
13C NMR: l 53.1 (CD2Cl2), 77.00 (CDCl3), 1.32
(CD3CN), 49.0 (CD3OD)). 31P{1H} NMR spectra were
recorded on a Bruker AC 200 MHz spectrometer using
85% phosphoric acid (l=0.00) as the external refer-
ence. Electron ionization mass spectra (EIMS, 70 eV),
chemical ionization mass spectra (CIMS), using NH3 as
the ionizing gas, and electrospray mass spectra (ESMS)
were run on a Finnigan 4000 spectrometer. All ESMS
samples were dissolved in methanol or CH2Cl2, as
noted below. Elemental microanalyses were performed
on a Perkin–Elmer 2400 series II C, H, N, S analyzer.
As previously described by Schmidbaur and co-work-
ers [49], triethylammonium chloride, Et3N·HCl, co-
crystallizes in the lattice of the (phosphine)-gold(I)-
benzenehexathiolate compounds along with the reac-
tion solvent, chloroform, to give an overall composition
of [(PPh3)Au]6(C6S6)·2Et3NHCl·4CHCl3. The solid
gold(I) and platinum(II) templates described in this
paper also contain Et3NHCl and the solvent CH2Cl2.
The presence of Et3NH+ and CH2Cl2 was established
by elemental analyses and 1H NMR spectra of the
compounds, which exhibit peaks with proper intensities
1
form and precipitated with methanol. Yield 75%. H
NMR: (CDCl3, l) 7.19 [30H, m], 4.00 [12H, s]. 13C
NMR: (CDCl3, l) 146.88, 137.28, 129.19, 128.34,
127.18, 42.32. EIMS: 810.2 (M+), 718 (M+−CH2Ph),
628 (M+−2CH2Ph), 536 (M+−3CH2Ph), 446 (M+−
4CH2Ph), 354 (M+−5CH2Ph). C48H42S6 Anal. Found:
C, 70.58; H, 5.12. Calc. for C48H42S6: C, 71.07; H,
5.22%.
2.2.2. Synthesis of hexasodium benzenehexathiolate,
C6(SNa)6 (6)
To 10 ml of anhydrous liquid ammonia at −78°C
was added 0.68 g (0.84 mmol) of 5 with stirring. Then
0.23 g (10 mmol) of elemental sodium was added in
three portions. A blue–green color appeared as the
sodium dissolved. The solution was stirred for 0.5 h at
−78°C. Degassed methanol was then added cautiously
to the flask until the blue color was discharged. The
flask was warmed to r.t. over 2 h. Afterwards, 10 ml of
degassed, deionized water was added and the aqueous
layer was extracted with ethyl ether (3×20 ml). The

276
J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
yellow aqueous layer was evaporated under reduced
pressure leaving behind 6 as an air-sensitive yellow
residue.
a yellow–white precipitate began to form. Then 20 ml
of hexanes were added to completely precipitate the
1
product. Yield 61%. H NMR: (CDCl3, l) 7.69 [2H,
m], 7.49 [3H, m], 6.28 [6H, m]. 13C NMR: (CDCl3, l)
136.55 [d, JC–P=30 Hz], 133.43 [d, JC–P=54 Hz],
131.92 [d, JC–P=9 Hz], 129.23 [d, JC–P=45 Hz],
128.32, 127.57. 31P{1H} NMR: (CDCl3, l) 26.16.
ESMS: 394 (M+), 360 (PhPAuCl), 252 (AuCl).
2.2.3. Synthesis of benzenehexathiol, C6(SH)6 (7)
To 3 ml of degassed, deionized water was added the
residue (0.25 g, 0.62 mmol) of 6 obtained in the above
procedure. Then 10 ml of a degassed 5% HCl solution
was added dropwise. The color changed from yellow to
red–brown, and a yellow solid precipitated from solu-
tion. The solid was filtered and dried under vacuum.
2.3.4. Synthesis of {[(C2H3)2(Ph)P]Au}6(C6S6) (1)
To 0.71 g (1.8 mmol) of 10 in 5 ml of CH2Cl2 was
added 0.080 g (0.30 mmol) of 7 and 25 ml (1.8 mmol) of
Et3N. The reaction was stirred at r.t. for 2 h. After this
time, the solution was filtered and the solvent was
removed under reduced pressure leaving behind a red–
brown residue. The residue was recrystallized at r.t.
from CH2Cl2 and hexanes. Yield 80%. 1H NMR:
1
Yield 55%. H NMR: (CD3CN, l) 2.19 [6H, s]. 13C
NMR: (CD3CN, l) 118.40. EIMS: 270 (M+), 236
(M+−H2S), 202 (M+−2H2S).
2.3. Gold-based template syntheses
To avoid decomposition to elemental gold, all reac-
tions of 9, 10, and 1 were carried out in the dark at
0°C.
(CDCl3, l) 7.65 [2H, m], 7.47 [3H, m], 6.16 [6H, m]. 13
C
NMR: (CDCl3, l) 136.91, 133.65, 133.36, 132.28,
129.67, 128.34. 31P{1H} NMR: (CDCl3, l) 22.59.
ESMS (MeOH): 2452 (M++MeOH), 2291 (M+−
(C2H3)2(Ph)P+MeOH+H), 2128 (M+−2(C2H3)2-
Ph)P+MeOH), 1967 (M+−3(C2H3)2(Ph)P+MeOH
+H). Anal. Found: C, 35.27; H, 4.16; N, 1.90. Calc.
for C66H66P6Au6S6·3(CH3CH2)3NHCl: C, 35.62; H,
4.06; N, 1.48%.
2.3.1. Synthesis of (di6inyl)(phenyl)phosphine,
(C2H3)2(Ph)P (8)
(Divinyl)(phenyl)phosphine was prepared using a
previously reported procedure [54]. Yield 60%. 1H
NMR: (CDCl3, l) 7.44 [2H, m], 7.29 [3H, m], 6.39 [2H,
m], 5.74 [4H, m]. 13C NMR: (CDCl3, l) 137.19, 136.61,
132.44, 128.66, 128.44. 31P{1H} NMR: (CDCl3, l)
−15.66. EIMS: 162 (M+), 135 (M+−C2H3), 108 (M+
−2C2H3).
2.3.5. Cyclization reaction of (1)
In a 5-mm glass NMR tube was placed 5.0 mg
(2.0×10−3 mmol) of 1, 0.6 ml of THF, 0.3 mg (1.9×
10−3 mmol) of AIBN (a-azoisobutylnitrile) and 10 ml
(9.1×10−2 mmol) of PhPH2. The tube was heated at
60°C in a hot water bath for 4.5 h. The yellow solution
was filtered and evaporated under reduced pressure to
give a red residue of the template macrocycle 2, which
was recrystallized at r.t. from CH2Cl2 and hexanes to
2.3.2. Synthesis of diethylsulfide gold(I) chloride
(Et2S)AuCl (9)
(Et2S)AuCl was prepared by a modified procedure
analogous to that reported for (Me2S)AuCl [55]. To a
solution of 1.0 g (2.94 mmol) of HAuCl4 in 25 ml of
deionized water at 0°C was slowly added 0.95 ml (8.82
mmol) ethyl sulfide in 2 ml of acetone. The solution
was stirred at r.t. in the dark for 1.5 h. After this time
the yellow color had discharged and a flocculant white
precipitate had formed. The solution was concentrated
to 15 ml under reduced pressure to ensure complete
precipitation. The white solid was filtered and dried
under vacuum with the flask in an ice water bath to
1
give a red solid. H NMR: (CD2Cl2, l) 7.78–7.40 [5H,
m], 1.25 [4H, m]. 13C NMR: (CD2Cl2, l) 134.83, 131.08
[m], 129.04 [m], 122.88, 31.14, 26.12. 31P{1H} NMR:
(CD2Cl2, l) 19.10, 14.36. ESMS (CH2Cl2): 3062 (M+
−18, very weak peak). Anal. Found: C, 35.79; H. 3.94;
N, 0.93. Calc. for C102H108Au6S6P12·2(CH3CH2)3-
NHCl·8CH2Cl2: C, 36.31; H, 3.90; N, 0.69%.
1
avoid decomposition. Yield 94%. H NMR: (CDCl3, l)
3.10 [2H, q], 1.45 [3H, t]. 13C NMR: (CDCl3, l) 32.09,
14.31. EIMS: 322 (M+), 62 (Et2S). Anal. Found: C,
13.72; H, 3.44; S, 9.07. Calc. for C4H10SAuCl·H2O: C,
14.10; H, 3.55; S, 9.41%.
2.3.6. Reaction of (2) with KCN
In a 5-mm glass NMR tube was placed product 2
(approximately 0.3 mg, 1 equiv.), 1.5 ml of D2O and 5.0
mg (33 equiv.) of KCN. The solution was heated at
50°C for 12 h in a hot water bath. Deuterated chloro-
form (1 ml) was then added and the tube was shaken
vigorously. After the layers had separated, the CDCl3
layer was removed, dried over anhydrous MgSO4 and
evaporated to give [P(Ph)CH2CH2]12 (11) as a yellow
oily solid, which in CD2Cl2 gave a single 31P{1H} NMR
signal at l 1.55.
2.3.3. Synthesis of [(di6inyl)(phenyl)phosphine)]gold(I)
chloride, [(C2H3)2(Ph)P]AuCl (10)
To 0.95 g (2.9 mmol) of 9 in 5 ml of CH2Cl2 at 0°C
in the dark was added 0.49 g (3.0 mmol) of 8 in 1 ml of
CH2Cl2. The solution was stirred at 0°C in the dark for
0.5 h. After this time, the CH2Cl2 was evaporated until

J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
277
2.4. Platinum-based template syntheses
4.54 [2H, t]. 31P{1H} NMR: (CD2Cl2, l) −63.96, Pt
satellites at −44.92, −82.91, JPt–P=3790 Hz. ESMS
(CH2Cl2): 2001 (M+−1).
2.4.1. Preparation of (PSP)PtCl2 complexes
[(cis-dppv)Pt]3(C6S6) (18): Yield 70%. 1H NMR:
(CDCl3, l) 7.81 [4H, m], 7.47 [16H, m], 7.23 [1H, s], 6.99
[1H, s]. 13C NMR: (CDCl3, l) 134.21, 133.51 [t], 132.20,
129.87, 129.12 [t]. 31P{1H} NMR: (CDCl3, l) 56.18, Pt
satellites at 71.02, 41.33, JPt–P=2968 Hz. ESMS
(CH2Cl2): 2038 (M+). Anal. Found: C, 46.32; H,
3.84; N, 0.87. Calc. for C84H66S6P6Pt3·(CH3CH2)3NHCl·
3CH2Cl2: C, 45.94; H, 3.65; N. 0.58%.
All (PSP)PtCl2 complexes were prepared by stirring
0.20 mmol of bis(benzonitrile)dichloroplatinum(II) and
0.20 mmol of the chelating phosphine in 5 ml of
methylene chloride at r.t. according to a previously
reported procedure [56,57]. Compounds 12–15 have
been previously prepared by other methods [58]. Abbre-
viations used for the PSP phosphines are dppp=1,2-
bis(diphenylphosphino)propane, dmpe=1,2-bis(dime-
thylphosphino)ethane, dppm=bis(diphenylphosphino)-
[(PPh3)2Pt]3(C6S6) (19): Yield 80%. 1H NMR: (CDCl3,
l) 7.49 [6H, t], 7.33 [3H, t], 7.15 [6H, t]. 31P{1H} NMR:
methane,
cis-dppv=cis-1,2-bis(diphenylphosphino)-
(CD2Cl2, l) 14.89, Pt satellites at 37.97, −7.91, JPt–P
=
ethylene, and ppp=1,3-bis(phenylphosphino)propane.
4616 Hz. ESMS (CH2Cl2): 2422 (M+−1), 2160 (M+−
PPh3), 1896 (M+−2PPh3). Anal. Found: C, 52.55; H,
4.07; N, 0.36. Calc. for C114H90P6S6Pt3·(CH3CH2)3-
NHCl·3CH2Cl2: C, 52.46; H, 4.01; N, 0.50%.
1
(dmpe)PtCl2 (12): Yield 88%. H NMR: (CD3OD, l)
2.24 [4H, t], 1.95 [12H, t]. 13C NMR: (CD3OD, l) 28.44
[m], 13.19 [m]. 31P{1H} NMR: (CDCl3, l) 34.19, Pt
satellites at 47.75, 20.65, JPt–P=2708 Hz. EIMS: 416
(M+, 195Pt), 150 (dmpe).
1
(dppm)PtCl2 (13): Yield 58%. H NMR: (CDCl3, l)
7.96 [8H, d], 7.47 [12H, m], 4.45 [2H, t]. 31P{1H} NMR:
3. Results and discussion
(CDCl3, l) −63.66, Pt satellites at −44.54, −82.70,
3.1. Gold-based template syntheses
J
Pt–P=3808 Hz. EIMS: 650 (M+, 195Pt), 614
([(dppm)PtCl]+), 384 (dppm). Anal. Found: C. 45.98; H,
For the purpose of constructing the 12 phosphorus-
donor macrocycle (2) in Scheme 1, the precursor hexa-
nuclear [(divinyl)(phenyl)phosphine]gold(I) benzene-
hexathiolate template (1) was easily prepared in one step
by stirring 6 equiv. of [(divinyl)(phenyl)phosphine]-
gold(I) chloride (10), 1 equiv. of benzenehexathiol (7)
and 6 equiv. of triethylamine in CH2Cl2 for 2 h at r.t.
(Eq. (1)).
3.39. Calc. for C25H22P2PtCl2: C, 46.17; H, 3.41%.
1
(cis-dppv)PtCl2 (14): Yield 72%. H NMR: (CDCl3,
l) 7.50 [22H, m]. 13C NMR: (CDCl3, l) 134.12 [m],
133.41 [m], 132.96, 132.16, 129.76 [m], 129.12 [m].
31P{1H} NMR: (CDCl3, l) 55.77, Pt satellites at 70.78,
40.76, JPt–P=3002 Hz. CIMS: 662 (M+, 195Pt), 397
(cis-dppv).
1
(ppp)PtCl2 (15): Yield 72%. H NMR: (CDCl3, l)
CH Cl
7.37 [10H, m], 2.80 [1H, s], 2.40 [1H, s], 1.53 [6H, m]. 13
C
2
2
6[(C2H3)2(Ph)P]AuCl+1C6(SH)6 ꢀꢀꢀꢀꢀꢀꢂ
(10)
(7)
6Et N
3
NMR: (CDCl3, l) 134.11, 131.78, 128.82, 123.20, 19.83,
19.68. 31P{1H} NMR: (CDCl3, l) −29.47, Pt satellites
at −15.49, −43.98, JPt–P=2848 Hz.
{[(C2H3)2(Ph)P]Au}6(C6S6)·3Et3NHCl+3Et3NHCl
(1)
(1)
2.4.2. Synthesis of [(PSP)Pt]3(C6S6) complexes
The resulting template product (1) is a red–brown
solid that contains 3 equiv. of Et3NHCl. The analogous
compound, [(Ph3P)Au]6(C6S6), prepared by Schmidbaur
and co-workers [49] also crystallized with 3 equiv. of
Et3NHCl. The presence and amount of triethylammo-
nium chloride in 1 was established by C, H, and N
elemental analyses, as well as correct integration values
for 1H NMR peaks (l=3.06 (q) and l=1.39 (t))
corresponding to the ethyl groups in the Et3NH+ cation.
Additionally, diagnostic peaks for the ethyl groups in
the Et3NH+ cation are observed in the 13C NMR
spectrum (l=46.94 and l=11.17). The 31P{1H} NMR
spectrum of 1 shows one signal at l=22.59, which is
shifted only slightly from that of the [(divinyl)-
(phenyl)phosphine]gold(I) chloride precursor 10 (l=
26.16). A multiplet at l=6.16 ppm (6H) in the 1H
NMR spectrum of 2 is characteristic of the vinyl protons
of the phosphine ligand, while the multiplets at l=7.47
and l=7.65 (5H) may be assigned to the phenyl group.
All [(PSP)Pt]3(C6S6) compounds were prepared by
stirring 0.025 mmol (3 equiv.) of (PSP)PtCl2, 8.4×10−3
mmol (1 equiv.) of 7 and 7 ml (5.0×10−2 mmol, 6
equiv.) of Et3N in 5 ml of CH2Cl2 (or 0.034 mmol of
Na2CO3 in 5 ml of MeOH for [(dmpe)Pt]3(C6S6)) at r.t.
for 2 h according to a procedure [49] similar to that
reported for the synthesis of [(PPh3)Au]6(C6S6). After
the 2 h period, the solvent was removed under reduced
pressure leaving behind a solid yellow residue that was
dissolved in CH2Cl2 and precipitated with hexanes at r.t.
[(dmpe)Pt]3(C6S6) (16): Yield 70%. 1H NMR:
(CD3OD, l) 2.23 [4H, t], 1.93 [12H, t]. 31P{1H} NMR:
(CD3OD, l) 36.33, Pt satellites at 49.82, 22.85, JPt–P
=
2696 Hz. ESMS (MeOH): 1299 (M+). Anal. Found: C,
20.24; H, 4.98. Calc. for C24H43S6Pt3P6·7H2O: C, 20.21;
H, 4.38%.
[(dppm)Pt]3(C6S6) (17): Yield 69%. 1H NMR:
(CD2Cl2, l) 8.01 [8H, m], 7.54 [10H, m], 7.39 [2H, m],

278
J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
The formation of the polyphosphorus macrocycle (2)
12, 16 PSP=dmpe, x=0, y=0, z=7
13, 17 PSP=dmpe, x=1, y=3, z=0
14, 18 PSP=cis-dppv, x=1, y=3, z=0
15, 19 PSP=2PPh3, x=1, y=3, z=0
was performed according to Scheme 1 by heating 1 at
60°C with excess PhPH2 and AIBN in THF for 4.5 h.
The templated macrocycle (2) was isolated as a red solid
by recrystallization from CH2Cl2 and hexanes. As ex-
pected from the structure of 2, the 31P{1H} NMR
spectrum shows only two signals l=19.10 and l=14.36
in CD2Cl2 in a 1:1 ratio. These two signals correspond
to the six phosphorus atoms directly coordinated to gold
and the six phosphorus atoms that lie between the
coordinated phosphorus atoms (Scheme 1). There exists
the possibility of multiple isomers resulting from differ-
ent stereochemistries at each of the 12-phosphorus
atoms. The presence of such isomers is supported by the
fact that each of the two 31P{1H} NMR signals is a broad
singlet. The 1H NMR spectrum, which exhibits no signals
for the vinyl groups of the precursor (1), shows a
multiplet for the phenyl protons at 7.78–7.40 ppm and
another multiplet for the methylene protons at 1.25 ppm;
their relative integrations (5:4) are correct for the pro-
posed structure of 2.
Three equivalents of the (PSP)PtCl2 complexes were
stirred with 1 equiv. of benzenehexathiol and 6 equiv. of
Et3N in CH2Cl2 for 2 h to give 16–19. As for the
gold-based system, Et3N·HCl and CH2Cl2 co-crystallize
in 17–19 as is evident from their elemental analyses and
1H NMR spectra. Compound 16 contains H2O whose
origin is unknown but is likely to be the solvents or
atmosphere. The 31P NMR chemical shifts and 31P–195Pt
coupling constants in 16–19 are very similar to those of
their precursor complexes 12–15. Electrospray mass
spectra of compounds 16–19 show peaks for the
[(PSP)Pt]3(C6S6) parent ions (M+) or (M+−1). At-
tempts to grow single crystals of 16–19 were unsuccess-
ful. All spectroscopic data are consistent with the
general formula [(PSP)Pt]3(C6S6) and confirm the 3:1
(PSP)Pt:C6S6 stoichiometry of the product.
In order to accomplish the cyclization in Scheme 2, we
also attempted the preparation of 3 containing the
bidentate secondary phosphine Ph(H)PCH2CH2CH2-
P(H)Ph (ppp), by the method (Eq. (2)) that was successful
for the synthesis of the other [(PSP)Pt]3(C6S6) complexes.
However, when 3 equiv. of (ppp)PtCl2 (15) were reacted
with 1 equiv. of benzenehexathiol (7) and 6 equiv. of
Et3N, the desired template (3) was not obtained. Since
Et3N is known to react with secondary phosphines [60],
which may have complicated the present reaction, we
used Na2CO3 as the base, but again 3 was not detected
despite the fact that Na2CO3 was used successfully in
place of Et3N to prepare [(dmpe)Pt]3(C6S6) (16). At
present, we do not understand why we have not been able
to prepare [(ppp)Pt]3(C6S6) (3), while all of the related
[(PSP)Pt]3(C6S6) complexes (16–19) are easily synthe-
sized. However, as a result, it was not possible to attempt
the macrocyclization reaction in Scheme 2.
Elemental analyses (C, H, and N) indicate that solid
2 contains two moles of Et3NHCl and 8 moles of CH2Cl2.
The presence and amount of Et3NHCl and CH2Cl2 is
1
confirmed by integrations of the H NMR peaks corre-
sponding to the protons in these compounds. Despite
several attempts to grow crystals for X-ray analysis, no
crystals of suitable size were obtained.
In a preliminary attempt to isolate the free macrocycle,
[P(Ph)CH2CH2]12 (11), a small amount of 2 was heated
(50°C) in an aqueous solution of KCN for 12 h. The
31P{1H} NMR spectrum of the CDCl3-soluble product
of this reaction shows only one signal at l=1.55, which
is consistent with the free macrocycle (11) that was
present in 2. This chemical shift is in good agreement
with that (l=4.1) reported for cyclic tetra(phenyl-
phosphino)methylene [P(Ph)CH2]4 [59]. More thorough
investigations of the macrocycle (11) will be undertaken
in the future.
3.2. Platinum-based template syntheses
4. Conclusions
Although the goal was to prepare 3 (Scheme 2) as the
precursor to macrocycle 4, the secondary phosphine
groups in the Ph(H)PCH2CH2CH2P(H)Ph (ppp) ligand
were expected to be air-sensitive and pose a challenge to
the synthesis of 3. In order to demonstrate that tem-
plates similar to 3 are synthetically accessible, we pre-
pared (Eq. (2)) analogs of 3 that contain the more stable
bidentate PSP phosphines: Ph2P(CH2)3PPh2 (dppp),
Me2P(CH2)2PMe2 (dmpe), Ph2PCH2PPh2 (dppm), cis-
Ph2PCHꢁCHPPh2 (cis-dppv) and (Ph3P)2.
For the purpose of using it as a template for the
formation of large-ring, polyphosphorus macrocycles,
the Au complex {[(divinyl)(phenyl)phosphine]Au}6-
(C6S6) (1) with a benzenehexathiolate core was prepared
and characterized. Its reaction (Scheme 1) with the
primary phosphine PhPH2 in the presence of AIBN
yielded the complex [P(Ph)CH2CH2]12Au6(C6S6) (2),
whose NMR spectra and elemental analyses are consis-
tent with the proposed structure which contains a 36-
membered ring with 12 phosphorus atoms, six of which
are coordinated to the six Au atoms. Although it
was possible to prepare a series of related platinum
complexes [(PSP)Pt]3(C6S6) (16–19), we were unable to
CH Cl
2
2
3(PSP)PtCl2+1C6(SH)6 ꢀꢀꢀꢀꢀꢀꢂ
(12−15)
(7)
6Et N
3
[(PSP)Pt]3(C6S6)·xEt3NHCl·yCH2Cl2·zH2O (2)
(16−19)

J.A. Harnisch, R.J. Angelici / Inorganica Chimica Acta 300–302 (2000) 273–279
279
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