Formation of thiolene versus dithiolene species from TTBEO. Crystal structures of [Au(ddtCO2Et)(PPh3)] and [Sn(ddtCO2Et)2-Me2] {TTBEO = 2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one; ddtCO2Et = 3-(ethoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate}

Article abstract of DOI:10.1039/a805064c

Thiolene gold(I) and tin(IV) complexes such as [Au(ddtCO₂R)L] [L = PPh₃, PPh₂Me or AsPh₃; R = Et or Me; ddtCO₂R = 3-(alkoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate] and [Sn(ddtCO₂R)₂Me₂] have been obtained from solutions of TTBEO {2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one} with sodium ethoxide or methoxide and the corresponding halogeno-complexes [AuCl(L)] and SnMe₂Cl₂. Reaction of the same solutions with [N(PPh₃)₂]₂[ZnCl₄] and [ZnCl₂(N-N)] [N-N = 1,10=phenanthroline (phen) or 2,2′-bipyridine (bipy)] afforded the dithiolene complexes [N(PPh₃)₂]₂[Zn(dddt)₂], [Zn(dddt)(phen)] and [Zn(dddt)(bipy)] which are the transmetallating starting materials for the synthesis of dithiolene gold(I) and tin(IV) complexes [{Au₂(dddt)(AsPh₃)}_n], [Au₂(dddt)(PPh₃)₂], [Au₂(dddt)(PPh₂Me)₂] and [Sn(dddt)Me₂]. The results point to the existence of both thiolene ddtCO₂R^- and dithiolene dddt^2- species in TTBEO solutions with sodium alkoxide. The crystal structures of [Au(ddtCO₂Et)(PPh₃)] and [Sn(ddtCO₂Et)₂Me₂] confirm the presence of the ethoxycarbonylsulfanyl ligand.

Full text of DOI:10.1039/a805064c

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Formation of thiolene versus dithiolene species from TTBEO.
Crystal structures of [Au(ddtCO2Et)(PPh3)] and [Sn(ddtCO2Et)2-
Me2] {TTBEO ؍ 2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one;
ddtCO2Et ؍ 3-(ethoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-
thiolate}
Elena Cerrada,a J. Felipe García,a Mariano Laguna,*a Raquel Terrobab and
M. Dolores Villacampaa
a Departamento de Química Inorgánica, Instituto de Ciencia de Materiales de Aragón,
Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain
b Departamento de Química, Universidad de la Rioja, Obispo Bustamante 3, 26001 Logroño,
Spain
Received 1st July 1998, Accepted 25th August 1998
Thiolene gold() and tin() complexes such as [Au(ddtCO2R)L] [L = PPh3, PPh2Me or AsPh3; R = Et or Me;
ddtCO2R = 3-(alkoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate] and [Sn(ddtCO2R)2Me2] have been
obtained from solutions of TTBEO {2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one} with sodium ethoxide or
methoxide and the corresponding halogeno-complexes [AuCl(L)] and SnMe2Cl2. Reaction of the same solutions
with [N(PPh3)2]2[ZnCl4] and [ZnCl2(N–N)] [N–N = 1,10=phenanthroline (phen) or 2,2Ј-bipyridine (bipy)] afforded
the dithiolene complexes [N(PPh3)2]2[Zn(dddt)2], [Zn(dddt)(phen)] and [Zn(dddt)(bipy)] which are the trans-
metallating starting materials for the synthesis of dithiolene gold() and tin() complexes [{Au2(dddt)(AsPh3)}n],
[Au2(dddt)(PPh3)2], [Au2(dddt)(PPh2Me)2] and [Sn(dddt)Me2]. The results point to the existence of both thiolene
ddtCO2RϪ and dithiolene dddt2Ϫ species in TTBEO solutions with sodium alkoxide. The crystal structures of
[Au(ddtCO2Et)(PPh3)] and [Sn(ddtCO2Et)2Me2] confirm the presence of the ethoxycarbonylsulfanyl ligand.
S
S
Se
Se
Se
Se
S
Se
S
S
S
Se
Se
Introduction
S
S
S
Se
S
Se
Se
Metal bis(1,2-dithiolene) complexes have been widely studied
over the past two decades1,2 as precursors for molecular metals
and superconductors. Owing to their nearly planar structures
they show large third order optical non-linearities,3,4 have good
properties for optical data storage,5,6 as well as unusual mag-
netic behaviour.7,8 The most studied complexes are those con-
taining the ligand 4,5-disulfanyl-1,3-dithiole-2-thiolate (C3S5,
dmit), which gives some examples of superconductors even
at ambient pressure as α-[EDT-TTF][Ni(C3S5)2].9 Conduct-
ing salts of dithiolene metal complexes tend to show one-
dimensional structures and most of them become insulating at
low temperatures. Ligands with one to five selenium atoms
instead of sulfur in dmit derivatives, or ligands with a more
extended sulfur framework, are the two strategies to prevent
Peierls’ transition to insulators by building up two- or three-
dimensional structures. The former gives rise to a number of
new ligands such as dmise (C3S4Se), dsit (C3S3Se2), dsise
(C3S2Se3) and dsis (C3Se5)10–13 and the latter to new ligands as
dddt, 5,6-dihydro-1,4-dithiin-2,3-dithiolate, the [M(dddt)2]nϪ
complexes of which show a related structure to bis(ethylene-
dithio)tetrathiafulvalene (BEDT-TTF). The latter is a donor
organic molecule which forms superconductor salts14,15 and
some of the charge transfer salts with [M(dddt)2] have been
reported to present metallic behaviour at low temperatures.16–28
Continuing with our latest research in dithiolene gold chem-
istry and the role of dithiolene tin() and zinc() complexes as
transmetallating reagents,29–31 in this work we select TTBEO
{2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one} as starting
material for the synthesis of dddt complexes of gold(), zinc()
and tin(). Formation of monothiolene ddtCO2R, 3-(alkoxy-
carbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate (R = Me
S
Se
S
S
S
dsit
dsise
dsis
dmit
dmise
n-
S
S
S
S
S
S
S
S
S
S
S
S
S
M
S
S
S
[M(dddt)2]n-
BEDT-TTF
S–
SCO2R
S
S
S
S–
S–
S
S
O
S
S
S
dddt
ddtCO2R
TTBEO
or Et), derivatives occurs in competition with the more frequent
dithiolene formation as evidenced by the crystal structures of
[Au(ddtCO2Et)(PPh3)] and [Sn(ddtCO2Et)2Me2]. Preparation
of dddt2Ϫ derivatives with the same metallic centres gold()
and tin() is achieved by other preparative procedures involv-
ing transmetallation reactions through the zinc complex
[N(PPh3)2]2[Zn(dddt)2] or [Zn(dddt)(N–N)] [N–N = 1,10-phen-
anthroline (phen) or 2,2Ј-bipyridine (bipy)].
Results and discussion
The synthesis of dddt complexes by reaction of the suitable
halogenometal complexes with dddt2Ϫ solutions prepared in situ
from TTBEO and sodium ethoxide or methoxide (Scheme 1)
J. Chem. Soc., Dalton Trans., 1998, 3511–3516
3511

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n–
S
S
S
S
S
S
S-
S-
S
S
S
S
S
S
S
S
(i)
(ii)
M
O
Scheme 1 (i) NaOR (2 equivalents) or Na in ROH (R = Me or Et);
(ii) [MCl4]nϪ
.
OR
O
S
S
S
S
Me
Sn Me
S
S
S
O
S
RO
Fig. 1 Molecule of complex 1 in the crystal with the atom numbering
scheme; H atoms are omitted for clarity.
R = Et 4, Me 5
(ii)
S
S
S
S
S AuL
AuL
O
S
S
S
S
(iii)
(i)
O
O
S
S
S
TTBEO
OMe
OEt
L = PPh3 6, AsPh3
7
L = PPh3 1, PPh2Me 2, AsPh3
3
(v)
(iv)
S
S
N
N
S
S
S
S
S
S
S
S
S
S
Zn
[N(PPh3)2]2
Zn
8
N-N = phen 9, bipy 10
(vii)
S
(vi)
(ix)
Fig. 2 Molecule of complex 4 in the crystal with the atom numbering
S
Me
Me
S-AuL
S-AuL
S
scheme; H atoms are omitted for clarity.
(viii)
Sn
[{Au(dddt)(AsPh3)}n]
S
resonances as a singlet flanked by two pairs of tin satellites:
S
S
11
2
2J(119SnH) = 65.2 and J(117SnH) = 62.5 Hz. In addition to a
14
L = PPh3 12, PPh2Me 13
triplet and a quartet corresponding to the ethyl group, it is
worth nothing that the methylene protons of SCH2CH2S
appear in this case as a singlet at δ 3.31. Similar results were
obtained when SnMe2Cl2 was added to solutions of TTBEO
with sodium methoxide and complex 5 [Sn(ddtCO2Me)2Me2]
was obtained. Also in this case the best yield was reached in the
presence of an excess of the tin derivative. The spectroscopic
properties of 5 are very close to those of 4 with the exception of
an extra methyl resonance instead of the ethyl ones. The mass
spectra of the tin complexes confirm their monomer nature and
show the parent peaks [M]ϩ at m/z (%) 656 (1) 4 and 628 (7) 5.
The presence of ddtCO2Et was confirmed by X-ray dif-
fraction analysis of complexes 1 and 4 (Figs. 1 and 2) and a
selection of bond distances and angles are listed in Tables 1
and 2. The former contains the gold atom in the usual linear
co-ordination for gold() complexes, with S–Au–P angle of
176.85(12)Њ. Unlike other phosphine gold() thiolate complexes
there are no intermolecular short gold–gold contacts in the lat-
tice, probably because of the bulkiness of both the triphenyl-
phosphine and the thiolate ligand with the carboxylate group,
preventing further contacts between gold atoms. The Au–P
bond length is 2.255(3)Å, very similar to those found in [Au-
(SR)(PPh3)] (R = Ph,32 C6H2Pri3-2,4,632, C17H15NSO2 33 or SC6-
H4SnBut2Cl31) derivatives, which lie in the range 2.2566(14)–
2.260(3) Å. The Au–S distance is 2.299(3) Å which is in the
range of those for the latter complexes [2.284(2)–2.3229(13)Å].
The tin atom in complex 4 is bonded to the sulfur atoms of
two ddtCO2Et ligands in a slightly distorted tetrahedral
arrangement with distances Sn–S(4) 2.455(2) and Sn–S(5)
2.440(2)Å and to the methyl groups with bond lengths Sn–
C(15) 2.125(6) and Sn–C(16) 2.109(6) Å similar to those in
other SnIV–C and SnIV–S compounds.34–38
Scheme 2 (i) NaOEt–EtOH ϩ [AuCl(L)]; (ii) NaOR–ROH ϩ SnMe2-
Cl2;(iii)NaOMe–MeOH ϩ [AuCl(L)];(iv)NaOEt–EtOH ϩ[N(PPh3)2]2-
[ZnCl4]; (v) NaOEt–EtOH ϩ [ZnCl2(N–N)]; (vi) [AuCl(AsPh3)]; (vii)
[AuCl(L)]; (viii) L; (ix) SnMe2Cl2.
has been described.17–19 As stated above, attempts to prepare
dinuclear dddt gold() complexes by a similar reaction, but
using [AuCl(L)] (L = PPh3, PPh2Me or AsPh3) instead of
[MCl4]nϪ salts, gave mononuclear derivatives containing a
CO2Et fragment attached to a sulfur atom [process (i), Scheme
2)]. Mononuclear thiolate complexes 1–3 [Au(ddtCO2Et)L]
were collected in good yields as insoluble yellow solids in
ethanol. The presence of one remaining ethyl carboxylate group
was clearly shown by one absorption at ≈1725 cmϪ1 in the IR
1
spectra and confirmed by their H NMR spectra showing the
inequivalence of CH2 protons of the ligand in agreement with
its unsymmetrical nature and the presence of a triplet and a
quartet corresponding to the ethoxy group. The positive-ion
liquid secondary ion mass spectra (LSIMSϩ) show the parent
peaks at m/z (%): 712 (30) 1, 650 (42) 2 and 756 (26) 3 in accord-
ance with their formulation. Complexes 1 and 2 can be
obtained by reaction of the triphenylarsine complex 3 with the
appropriate phosphine in a 1:1 ratio.
When SnMe2Cl2 was added to solutions of TTBEO in
sodium ethoxide complex 4 [Sn(ddtCO2Et)2Me2] was obtained
[process (ii), Scheme 2]. Although a stoichiometric ratio Sn:
TTBEO of 1:2 is present in the final compound, the best results
were obtained when a 1:1 ratio was used. Others ratios gave
oily mixtures from which it was impossible to crystallize com-
plex 4. Its IR spectrum shows an ester absorption at 1728 cmϪ1
similar to those of complexes 1–3 and the 1H NMR spectrum is
in accordance with the formulation showing the methyl tin
3512
J. Chem. Soc., Dalton Trans., 1998, 3511–3516

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Table 1 Selected bond lengths (Å) and angles (Њ) for complex 1
S–
S
S–
S–
S
S
S
S
S
S
S
S
RO–
RO–
OR
OR
+
O
O
Au–P
P–C(31)
2.255(3)
Au–S(1)
2.299(3)
O
1.837(12)
1.740(10)
1.763(10)
1.750(10)
1.172(11)
1.473(12)
1.533(14)
S(1)–C(1)
S(2)–C(2)
S(3)–C(3)
S(4)–C(5)
O(2)–C(5)
C(1)–C(4)
C(6)–C(7)
1.772(10)
1.811(10)
1.783(11)
1.799(11)
1.298(11)
1.352(12)
1.391(14)
OR
S(2)–C(1)
S(3)–C(4)
S(4)–C(4)
O(1)–C(5)
O(2)–C(6)
C(2)–C(3)
Scheme 3 Equilibrium in solution between TTBEO, ddtCO2RϪ and
dddt2Ϫ
.
1
able to ν(C᎐O) and the H NMR spectra show singlets for the
᎐
methoxy group and a multiplet at ca. δ 3.3 for methylene
protons. Their LSIMSϩ mass spectra show the parent peaks at
m/z (%) 698(37) 6 and 742(21) 7.
P–Au–S(1)
176.85(12)
103.7(5)
100.6(5)
126.0(8)
114.3(5)
112.0(8)
128.2(8)
128.6(11)
105.5(8)
C(1)–S(1)–Au
C(4)–S(3)–C(3)
C(5)–O(2)–C(6)
C(4)–C(1)–S(1)
C(3)–C(2)–S(2)
C(1)–C(4)–S(4)
S(4)–C(4)–S(3)
O(1)–C(5)–S(4)
C(7)–C(6)–O(2)
103.2(3)
103.3(5)
116.5(9)
119.7(8)
111.5(8)
122.4(8)
109.4(5)
125.9(9)
108.1(10)
C(1)–S(2)–C(2)
C(4)–S(4)–C(5)
C(4)–C(1)–S(2)
S(2)–C(1)–S(1)
C(2)–C(3)–S(3)
C(1)–C(4)–S(3)
O(1)–C(5)–O(2)
O(2)–C(5)–S(4)
As stated above in this way only ddtCO2RϪ complexes of
gold() and tin() were obtained, but changing the strategy
it was possible to obtain dddt complexes with these metals.
Zinc complexes such as [N(PPh3)2]2[ZnCl4] and [ZnCl2(N–N)]
(N–N = phen or bipy) react with solutions of TTBEO with
either ethoxide or methoxide in the corresponding alcohol,
affording dddt2Ϫ complexes [N(PPh3)2]2[Zn(dddt)2] 8, [Zn-
(dddt)(phen)] 9 and [Zn(dddt)(bipy)] 10 [processes (iv) and (v),
Scheme 2]. The yields of these complexes are quite high and no
evidence of monothiolate ddtCO2R complexes was detected.
The 1H NMR spectra are in accordance with their formulation,
showing the methylene dddt resonances as singlets in addition
to other resonances due to N(PPh3)2, phen or bipy. Although
complexes 8 and 9 are slightly soluble in most of the common
solvents, their LSIMSϩ mass spectra show the mononuclear
species as the parent peak at m/z (%) 424(15) 9 and 400(10) 10
pointing to the mononuclear nature of these complexes. Owing
to the dicationic nature of 8, its mass spectrum does not show
either the parent ion peak or related peaks, although it acts as a
Table 2 Selected bond lengths (Å) and angles (Њ) for complex 4
Sn–C(16)
Sn–S(5)
2.109(6)
2.440(2)
1.740(7)
1.744(6)
1.760(6)
1.775(6)
1.745(7)
1.749(7)
1.763(8)
1.171(8)
1.457(8)
1.318(8)
1.482(10)
1.415(10)
Sn–C(15)
Sn–S(4)
2.125(6)
2.455(2)
1.802(8)
1.780(8)
1.785(8)
1.772(6)
1.795(8)
1.833(9)
1.765(7)
1.334(8)
1.200(8)
1.450(8)
1.343(8)
1.339(9)
S(1)–C(3)
S(2)–C(4)
S(3)–C(4)
S(4)–C(3)
S(6)–C(10)
S(7)–C(11)
S(8)–C(12)
O(1)–C(5)
O(2)–C(6)
O(4)–C(12)
C(1)–C(2)
C(8)–C(9)
S(1)–C(1)
S(2)–C(2)
S(3)–C(5)
S(5)–C(10)
S(6)–C(9)
S(7)–C(8)
S(8)–C(11)
O(2)–C(5)
O(3)–C(12)
O(4)–C(13)
C(3)–C(4)
C(10)–C(11)
2:1 electrolyte39 in acetone solution, ΛM 159 ohmϪ1 cm2 molϪ1
.
In order to show that these different behaviours are depend-
ent on the metal complexes used we prepared only one solu-
tion of TTBEO with sodium ethoxide–ethanol or sodium
methoxide–methanol and divided it in two equal parts;
[AuCl(PPh3)] or [N(PPh3)2]2[ZnCl4] were added, respectively.
Complexes 1 or, respectively, 6 and 8 were obtained in more
than 80% yield. These results point out that the two species
mono-ddtCO2RϪ and di-thiolene dddt2Ϫ should be present in
solution and the equilibrium (Scheme 3) is displaced to one or
other extreme depending on the products formed. Another pos-
sible explanation could be the presence of only ddtCO2RϪ in
solution which could remain after the co-ordination to gold()
or tin() or could evolve with subsequent removal of the CO2R
group after the co-ordination of the two sulfur sites to the more
polarizing and Lewis acidic zinc() centre.
C(16)–Sn–C(15)
C(15)–Sn–S(5)
C(15)–Sn–S(4)
C(4)–C(3)–S(1)
S(1)–C(3)–S(4)
C(3)–C(4)–S(3)
O(1)–C(5)–O(2)
O(2)–C(5)–S(3)
C(11)–C(10)–S(5)
C(10)–C(11)–S(7)
S(7)–C(11)–S(8)
O(3)–C(12)–S(8)
118.9(3)
106.2(2)
111.9(2)
126.2(5)
110.6(4)
121.7(5)
127.2(8)
105.4(6)
123.0(6)
127.5(6)
109.7(4)
125.9(6)
C(16)–Sn–S(5)
C(16)–Sn–S(4)
S(5)–Sn–S(4)
112.3(2)
104.4(2)
101.90(8)
123.1(5)
128.6(5)
109.6(4)
127.4(6)
127.1(5)
109.9(4)
122.7(6)
127.0(7)
107.2(6)
C(4)–C(3)–S(4)
C(3)–C(4)–S(2)
S(2)–C(4)–S(3)
O(1)–C(5)–S(3)
C(11)–C(10)–S(6)
S(6)–C(10)–S(5)
C(10)–C(11)–S(8)
O(3)–C(12)–O(4)
O(4)–C(12)–S(8)
The ligands ddtCO2Et in both complexes are quite similar.
The sulfur atoms connected with the metal centres show sulfur–
carbon distances ≈ 1.77 Å which are intermediate between
single (1.81 Å) and double bonds (1.71 Å), indicating a slight
degree of electron delocalization. The sulfur–carbon distances
in the dithiacycle are slightly different depending on the char-
acter of the connected carbon atom. The shortest distances
correspond to the sp2 hybridized carbon [average 1.747(8) Å]
compared with the sulfur–methylene carbon distances [average
1.801(9) Å]. The carbon–carbon distances of the planar C2S4
moieties [C(1)–C(4) 1.352(12) Å in 1 and C(3)–C(4) 1.343(8),
C(10)–C(11) 1.339(9) Å in 4] correspond to double bond values.
The carboxylate groups show two different carbon–oxygen
distances corresponding to double and single bonds. It is
noteworthy that with the exception of the CO2Et group all
these distances are very similar to those shown by dddt2Ϫ com-
plexes as in [MoCp2(dddt)]28 and one of the dddt ligands in
[Au(dddt)2].18
Zinc dddt2Ϫ complexes are the starting material to synthesize
gold() and tin() complexes of these ligands by transmetalla-
tion reactions as reported with other dithiolene derivatives.29–31
So the reaction of [N(PPh3)2]2[Zn(dddt)2] with [AuCl(L)] (L =
AsPh3, PPh3 or PPh2Me) in acetone in 1:4 ratio afford insoluble
dithiolene complexes [{Au2(dddt)(AsPh3)}n] 11, [Au2-
(dddt)(PPh3)2] 12 or [Au2(dddt)(PPh2Me)2] 13 respectively
which were recovered by filtration [processes (vi) and (vii),
Scheme 2]. The stoichiometry of the triphenylarsine complex,
11, is different from those of the phosphine derivatives, 12 and
13. Although the mass spectra of 11 cannot provide inform-
ation because of its poor ionization we think that 11 could have
a similar structure to those proposed for other dithiolene–arsine
gold complexes40 (dithiolene = S2C6H4 or S2C6H3Me) and
therefore should be tetranuclear. In a similar way to the previ-
ous arsine complex 3, the reaction of 11 with different phos-
phines such as PPh3 and PPh2Me renders complexes 12 and 13
in very good yields [process (viii), Scheme 2]. The mass spectra
of the latter confirm the dinuclear nature with the presence of
The reaction of TTBEO with sodium methoxide in methanol
with gold halide complexes affords [Au(ddtCO2Me)L] (L =
PPh3 6 or AsPh3 7) [process (iii), Scheme 2] only at 0 ЊC in an
ice-bath, otherwise some impurities corresponding to [Au2-
(dddt)L2] complexes appear (see below). Complexes 6 and 7
show IR absorption at 1719 and 1730 cmϪ1 respectively, assign-
1
the base peak at m/z (%) 1098(41) 12 and 974(24) 13. The H
NMR spectra show singlets for the methylene protons of dddt
and also singlets for the phosphorus in the 31P-{1H} NMR spec-
tra showing their equivalence in agreement with the proposed
structure.
J. Chem. Soc., Dalton Trans., 1998, 3511–3516
3513

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3
The preparation of tin() dddt complexes can be achieved by
a similar transmetallation reaction starting from [N(PPh3)2]2-
[Zn(dddt)2] and SnMe2Cl2 in 1:2 ratio in acetone. The fact that
all the resulting reaction products are insoluble in acetone pre-
vents a good separation. Better results were obtained using
[Zn(dddt)(phen)] 9 as starting material with SnMe2Cl2 in 1:2
ratio in the same solvent. Both zinc complexes, the starting 9
and the reaction product [ZnCl2(phen)], are insoluble in this
medium and were recovered by filtration. From the solution
CH2S); 3, 7.69–7.43 (m, 15 H, Ph), 4.25 (q, JHH = 7.1, 2 H,
CH2), 1.27 (t, 3 H, CH3), 3.38 (m, 2 H, SCH2CH2S), 3.3 (m, 2 H,
SCH2CH2S), 2.13 (d, JHH = 10.2 Hz, 3 H, CH3). 31P-{1H}
3
NMR (CDCl3): 1, δ 35.6 (s); 2, 18.3 (s). Mp 132 (1), 78
(decomp.) (2), 124 ЊC (3). (Found: C, 42.0; H, 3.35; S, 18.5.
Calc. for C25H24AuO2PS4 1: C, 42.15; H, 3.3; S, 18.0. Found: C,
36.45; H, 3.05; S, 19.05. Calc. for C20H22AuO2PS4 2: C, 36.9; H,
3.4; S, 19.7. Found: C, 39.1; H, 3.2; S, 17.4. Calc. for C25H24-
AsAuO2S4 3: C, 39.7; H, 3.2; S, 16.9%) ΛM/ohmϪ1 cm2 molϪ1 = 2
(1), 1 (2,3).
1
complex [Sn(dddt)Me2] 14 was obtained in a 70% yield. Its H
NMR spectrum shows a singlet for the methylene protons of
dddt and also a singlet for the methyl groups attached to Sn as
confirmed by the presence of two pairs of satellites correspond-
ing to 119Sn and 117Sn isotopomers. The mass spectrum shows
the parent peak at m/z (%) 330(8).
(b) To a solution of complex 3 (0.076 g, 0.1 mmol) in 15 ml of
dichloromethane was added PPh3 (0.029 g, 0.1 mmol) or
PPh2Me (0.020 g, 0.1 mmol). After 2 h of stirring at room
temperature the solutions were concentrated and the addition
of 15 ml of diethyl ether gave yellow solids 1 and 2, which were
filtered off and dried in vacuo.
Conclusion
[Sn(ddtCO2R)2Me2] (R ؍ Et 4 or Me 5). To a suspension of
TTBEO (0.042 g, 0.2 mmol) in 10 ml of ethanol was added a
solution of 0.1 M NaOEt (0.8 mmol, 8 ml) under dinitrogen
during 10 min and SnCl2Me2 (0.042 g, 0.2 mmol). After 12 h of
stirring the solution was filtered off through 1 cm of Celite,
concentrated to dryness, dissolved in 15 ml of CH2Cl2, concen-
trated and the addition of 20 ml of n-hexane led to white solid
4, which was filtered off and dried in vacuo. To a suspension of
TTBEO (0.042 g, 0.2 mmol) in 10 ml of methanol was added a
solution of 0.1 M NaOMe (0.8 mmol, 8 ml) under dinitrogen
during 10 min and SnCl2Me2 (0.042 g, 0.2 mmol). After 12 h of
stirring the solution was concentrated to gave a white solid (5).
The solid was filtered off and dried in vacuo. Yields: 4, 82, 5,
When TTBEO reacts with an excess of sodium ethoxide or
methoxide in the corresponding alcohol and after the addition
of different halogenometal complexes, monothiolene, ddt-
CO2R, or dithiolene, dddt, derivatives could be obtained. So,
with gold() complexes such as [AuCl(L)] and the tin() deriv-
ative SnMe2Cl2 monothiolene complexes were obtained. On the
contrary, with zinc complexes it was possible to obtain dithio-
lene derivatives which were used as transmetallation reagents
for the synthesis of dddt derivatives of gold() and tin(). The
synthesis of both ddtCO2R and dddt complexes of gold() and
tin() by two different ways and their stability illustrates the
importance of the synthetic pathway in inorganic synthesis. The
different behaviour of TTBEO alkoxide solutions depending on
the metal complexes used should be taken into account in order
to understand some unsuccessful attempts to prepare dddt and
related complexes.41,42 Probably mono- and di-thiolene species
should be formed in other ketone or thione degradations giving
dithiolene derivatives.
79% (based on TTBEO). IR(film): ν(C᎐O) 1728 (4), 1700 cmϪ1
᎐
(5). 1H NMR (CDCl3): 4, δ 4.27 (q, 3JHH = 7, 2 H, CH2), 1.29 (t,
3 H, CH3), 3.31 (s, 8 H, SCH2CH2S) and 0.98 [s, J(119Sn–
H) = 65.2 and J(117Sn–H) = 62.5 Hz, 6 H, CH3]; 5, 3.82 (s, 6 H,
OMe), 3.31 (s, 8 H, SCH2CH2S) and 0.99 [s, J(119SnH) = 66
and J(117SnH) = 62 Hz, 6 H, CH3]. Mp 120 (decomp.) (4),
96 ЊC (5). (Found: C, 29.2; H, 3.5; S, 39.0. Calc. for
C16H24O4S8Sn 4: C, 29.3; H, 3.7; S, 39.1. Found: C, 26.4; H, 2.9;
S, 40.4. Calc. for C14H20O4S8Sn 5: C, 26.8; H, 3.2; S, 40.8%).
Experimental
The compounds TTBEO,43 [AuCl(PPh3)],44 [AuCl(PPh2Me)]44
and [AuCl(AsPh3)]45 were obtained according to the literature
procedures.
[Au(ddtCO2Me)(L)] (L ؍ PPh3 6 or AsPh3 7). (a) To a sus-
pension of TTBEO (0.021 g, 0.1 mmol) in 10 ml of methanol
was added a solution of 0.1 M NaOMe (0.4 mmol; 4 ml) under
dinitrogen during 10 min and [AuCl(PPh3)] (0.049 g, 0.1 mmol)
or [AuCl(AsPh3)] (0.054 g, 0.1 mmol). After stirring for 1.5 h
the yellow 6 and brown 7 solids obtained were filtered off,
washed with methanol and dried in vacuo. Yields: 6, 80; 7, 65%.
Infrared spectra were recorded on a Perkin-Elmer 559 or 883
spectrophotometer, over the range 4000–200 cmϪ1, by using
Nujol mulls between polyethylene sheets, 1H and 31P NMR
spectra on a Varian UNITY 300 in CDCl3 solutions; chemical
shifts are quoted relative to SiMe4 (1H) and H3PO4 (external
31P). The C,H,N and S analyses were performed with a Perkin-
Elmer 2400 microanalyser. Conductivities were measured in
approximately 5 × 10Ϫ4 mol dmϪ3 acetone solutions, with a
Philips PW 9509 apparatus. Mass spectra were recorded on a
VG Autospec, by LSIMSϩ using 3-nitrobenzyl alcohol as
matrix and a caesium gun. The melting points were measured in
a Gallekamp apparatus and are uncorrected.
IR(film): ν(C᎐O) 1719 (6), 1730 cmϪ1 (7). 1H NMR (CDCl3): 6,
᎐
δ 7.7–7.3 (m, 15 H, Ph), 3.74 (s, 3 H, OMe), 3.37 (m, 2 H,
SCH2CH2S) and 3.28 (m, 2 H, SCH2CH2S); 7, δ 7.7–7.1 (m,
15 H, Ph), 3.74 (s, OMe), 3.36 (m, 2 H, SCH2CH2S) and 3.22
(m, 2 H, SCH2CH2S). 31P-{1H} NMR (CDCl3) 6, δ 38.4 (s). Mp
120 (6), 98 ЊC (7). (Found: C, 41.7; H, 2.85; S, 17.9. Calc. for
C24H22AuO2PS4 6: C, 41.25; H, 3.15; S, 18.35. Found: C, 38.3;
H, 2.35; S, 16.55. Calc. for C24H22AsAuO2S4 7: C, 38.8; H, 2.9;
S, 17.3%). ΛM/ohmϪ1 cm2 molϪ1 = 1 (6), 2 (7).
Syntheses
[Au(ddtCO2Et)(L)] (L ؍ PPh3 1, PPh2Me 2 or AsPh3 3). (a)
To a suspension of TTBEO (0.021 g, 0.1 mmol) in 10 ml of
ethanol was added a solution of 0.1 M NaOEt (0.4 mmol, 4 ml)
under dinitrogen during 10 min and [AuCl(PPh3)] (0.049 g,
0.1 mmol), [AuCl(PPh2Me)] (0.043 g, 0.1 mmol) or [AuCl-
(AsPh3)] (0.054 g, 0.1 mmol). After stirring for 24 h yellow
solids precipitated, which were filtered off, washed with ethanol
[N(PPh3)2]2[Zn(dddt)2] 8. To a suspension of TTBEO (0.104
g, 0.5 mmol) in 10 ml of ethanol was added a solution of 0.1 M
NaOEt (2 mmol; 2 ml) under dinitrogen during 10 min and
[N(PPh3)2]2[ZnCl4] (0.160 g, 0.25 mmol). After 12 h of stirring a
yellow solid precipitated, which was filtered off, washed with
1
water (2 × 10 ml) and dried with diethyl ether. Yield: 85%. H
NMR (CDCl3): δ 7.7–7.3 (m, 30 H, Ph) and 3.31 (s, 8 H, SCH2-
CH2S). Mp 116 ЊC. (Found: C, 63.5; H, 4.8; N, 2.0; S, 16.2.
Calc. for C80H68N2P4S8Zn: C, 63.9; H, 4.6; N, 1.7; S, 17.1%).
and dried in vacuo. Yields: 1, 82; 2, 64; 3, 90%. IR (film): ν(C᎐O)
᎐
1723 (1), 1720 (2), 1725 cmϪ1 (3). 1H NMR (CDCl3): 1, δ 7.52–
7.49 (m, 15 H, Ph), 4.26 (q, 3JHH = 6.7 Hz, 2 H, CH2), 1.27 (t, 3
H, CH3), 3.4 (m, 2 H, SCH2CH2S), 3.3 (m, 2 H, SCH2CH2S); 2,
ΛM = 159 ohmϪ1 cm2 molϪ1
.
3
7.55–7.45 (m, 10 H, Ph), 4.23 (q, JHH = 7 Hz, 2 H, CH2), 1.25
[Zn(dddt)(N–N)] (N–N ؍ phen 9 or bipy 10). To a suspension
(t, 3 H, CH3), 3.36 (m, 2 H, SCH2CH2S), 3.3 (m, 2 H, SCH2-
of TTBEO (0.025 g, 0.25 mmol) in 10 ml of methanol was
3514
J. Chem. Soc., Dalton Trans., 1998, 3511–3516

View Article Online
Table 3 Data collection and structure refinement for complexes 1
and 4
Crystallography
Data for complexes 1 and 4 were collected on a Stoe-Siemens
four-circle diffractometer using monochromated Mo-Kα radi-
ation (λ = 0.71073 Å), scan type θ–2θ. Data for 1 were measured
at Ϫ100 ЊC and for 4 at room temperature. Cell constants were
refined from setting angles of 48 reflections in the range 2θ 15–
27 for 1 and 15–34Њ for 4. Absorption corrections were applied
on the basis of ψ scans. Structures were solved by the heavy-
atom method and refined on F 2 using the program SHELXL
93.46 All non-hydrogen atoms were refined anisotropically.
Hydrogen atoms were included using a riding model except
methyl hydrogens bonded to tin which were included as rigid
groups. A system of restraints to light-atom displacement-
factor components and local ring symmetry was used in 1; no
restraints in 4. The significant residual electron density in 1 is in
the heavy atom region; the distance of the maximum peak,
1.053 e ÅϪ3, to the nearest atom (Au) is 0.99 Å. Further details
are given in Table 3.
1
4
Chemical formula
M
Crystal system
Space group
C25H24AuO2PS4
712.62
C16H24O4S8Sn
655.52
Monoclinic
P21/c
Triclinic
P1
¯
a/Å
b/Å
c/Å
α/Њ
9.202(5)
11.495(6)
13.921(7)
70.85(4)
87.05(4)
74.24(2)
1337.6(12)
2
7.623(3)
20.585(4)
17.012(3)
—
90.53(4)
—
β/Њ
γ/Њ
V/Å3
2669.4(13)
4
Z
T/K
193(2)
5.892
4526
4193
293(2)
1.603
5826
µ(Mo-Kα)/mmϪ1
No. reflections measured
No. unique reflections
No. reflections observed
[F > 4σ(F )]
4687
2897
0.054
0.092
4193
298
2764
0.054
0.101
4686
264
CCDC reference number 186/1136.
See http://www.rsc.org/suppdata/dt/1998/3511/ for crystallo-
graphic files in .cif format.
R [F, F > 4σ(F )]
wR (F 2, all reflections)
No. reflections used
No. parameters
Acknowledgements
We thank the Dirección General de Investigación Científica y
Técnica (PB95-0140) for financial support.
added [ZnCl2(phen)] (0.079 g, 0.25 mmol) or [ZnCl2(bipy)]
(0.073 g, 0.25 mmol). After 3 d of stirring complexes 9 and 10
precipitated as red and brown solids, which were filtered off and
1
dried in vacuo. Yields: 9, 75, 10, 72%. H NMR (CDCl3): 9,
δ 9.04 (m, 2 H, phen), 8.53 (m, 2 H, phen), 8.02 (s, 2 H, phen),
7.79 (m, 2 H, phen) and 3.03 (s, 4 H, SCH2CH2S); 10, 8.66 (m,
2 H, bipy), 8.34 (m, 2 H, bipy), 7.79 (m, 2 H, bipy), 7.42 (m,
2 H, bipy), 3.04 (s, 4 H, SCH2CH2S) and 7.6–7.4 (m, bipy). Mp
193 (9), 214 ЊC (10). (Found: C, 44.65; H, 2.3; S, 31.0. Calc. for
C16H12N2S4Zn 9: C, 45.1; H, 2.8; S, 30.1. Found: C, 41.55; H,
2.55; S, 30.8. Calc. for C14H12N2S4Zn 10: C, 41.8; H, 3.0; S,
31.9%).
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Paper 8/05064C
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J. Chem. Soc., Dalton Trans., 1998, 3511–3516