Synthesis, characterization and crystal structures of organolead dithiolate compounds displaying transannular interactions D···Pb (D = O, S)

Article abstract of DOI:10.1016/j.poly.2008.11.012

Treatment of Ph₂PbCl₂ with O(C₆H₄SH)₂ (1a), S(C₆H₄SH)₂ (2a) and S(C₆H₃SH)₂O (3a) afforded the stable organolead compounds [{O(C_6<

Full text of DOI:10.1016/j.poly.2008.11.012

Polyhedron 28 (2009) 467–472
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Synthesis, characterization and crystal structures of organolead dithiolate
compounds displaying transannular interactions DꢀꢀꢀPb (D = O, S)
Simplicio González-Montiel a, Benito Flores-Chávez a, José G. Alvarado-Rodríguez a,
Noemí Andrade-López a, Juan Antonio Cogordan b
,
*
a Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Hidalgo, Km. 4.5 Carretera Pachuca-Tulancingo, Col. Carboneras,
Mineral de la Reforma, Hidalgo, C.P. 42184, Mexico
b Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, D.F. México. C.P. 04510, Mexico
a r t i c l e i n f o
a b s t r a c t
Article history:
Treatment of Ph2PbCl2 with O(C6H4SH)2 (1a), S(C6H4SH)2 (2a) and S(C6H3SH)2O (3a) afforded the stable
organolead compounds [{O(C6H4S)2}PbPh2] (1b), [{S(C6H4S)2}PbPh2] (2b) and [{S(C6H3S)2O}PbPh2] (3b).
X-ray structure determinations of dithiolate-diphenyl lead compounds 1b–3b revealed that the trichal-
cogenated ligands are tridentate in 1b and 2b, and bidentate in 3b. The lead atom acts as an acceptor
atom exhibiting weak intramolecular transannular interactions with the donor D atom, with tetrahedral
distortions of 48% for 1b, 51% for 2b and 45% for 3b. The local geometry at the lead atom is described as
monocapped tetrahedral. The crystal packing of title compounds is stabilized by several non-bonded
interactions.
Received 10 October 2008
Accepted 18 November 2008
Available online 26 December 2008
Keywords:
Organolead compounds
Dithioligands
Hypercoordinated compounds
Non-bonded interactions
Structure elucidation
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
in order to achieve hypercoordination at the lead atom. The choice
of the PbPh2 moiety is widely supported due is less toxic than their
Hypercoordination through non-bonded intramolecular as well
as intermolecular interactions is well documented in compounds
containing group 14 elements [1,2]. So far lead, the heaviest atom
in the group with environmental and toxicological relevance, show
the broadest possibilities for coordination numbers and coordina-
tion geometries. The higher coordination numbers are usually
achieved by intra- or intermolecular bonding with ligands poten-
tially polydentate bearing several soft and/or hard donors [3–7].
On the other hand, we are interested in the synthesis and design
of ligands capable to promote the expansion of the coordination
number of heavy p-block elements; such ligands are D(C6H4SH)2
[D = O, S] and S(C6H4SH)2O and they yield hypercoordinated com-
pounds of type I and II, respectively [8–12]. In these compounds,
hypercoordination is achieved by a transannular DꢀꢀꢀA interaction
(Scheme 1). In general, has been observed that the coordination
ability of the ligands can be tuned by the appropriate choice of
the exocyclic ligands attached to A, prompting a bidentate or, in
most of the cases, tridentate coordination pattern.
aliphatic counterparts. The molecular and crystal structures of
compounds 1b, 2b and 3b were obtained by X-ray diffraction stud-
ies. The detailed description of the synthesis, spectroscopic charac-
terization and crystallographic data are presented and discussed
below.
2. Experimental
2.1. Materials and methods
All manipulations were performed under a dry, oxygen-free ar-
gon atmosphere using standard Schlenk techniques unless noted
otherwise. Solvents were dried by standard methods and distilled
prior to use. S(C6H4SH)2, [13] O(C6H4SH)2 [8] and S(C6H3SH)2O
[12] were synthesized according to literature methods. Ph2PbCl2
and n-BuLi (1.6 M, in hexanes) were purchased from Alfa Aesar
and Aldrich respectively and were used as supplied. Melting points
were determined with a Mel-Temp II instrument and are uncor-
rected. Spectra were recorded with the following instruments.
Mass spectra: EI, 70 eV, Hewlett Packard MS-598 mass spectrome-
ter. The elemental analyses were recorded with a Perkin–Elmer
Series II CHNS/O Analyzer. The IR spectra were recorded in the
4000–400 cmꢁ1 range with a Perkin–Elmer System 2000 FT-IR
spectrometer, as KBr pellets. The NMR spectra were recorded with
Following with the study of hypercoordination in group 14 ele-
ments, herein we report the synthesis and characterization of three
diphenyl lead organometallic compounds containing a transannu-
lar interaction DꢀꢀꢀPb, where the flexibility of the ligands is crucial
* Corresponding author. Tel.: +52 771 7172000.
a
Jeol Eclipse 400 spectrometer at 25 °C, with the residual
E-mail address: josegalvarado@yahoo.com (J.G. Alvarado-Rodríguez).
0277-5387/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2008.11.012

468
S. González-Montiel et al. / Polyhedron 28 (2009) 467–472
128.2 [C2], 126.9 [C3] ppm. IR (KBr pellet, cmꢁ1): 3057, 3040,
1565, 1471, 1438, 1430, 1242, 1099, 1040, 1011, 994, 840, 746,
720, 687 cmꢁ1
S
D
.
O
E
E
2.2.3. Synthesis of [{S(C6H4S)2O}PbPh2] (3b)
E
E
A
I
A
II
Ph2PbCl2, (0.13 g, 0.30 mmol) was added to a solution of
S(C6H3SH)2O (3a, 0.08 g, 0.30 mmol) in 15 mL of dry methanol at
room temperature. The solution was refluxed overnight. The yel-
low solid obtained was filtered and dissolved in chloroform
(30 mL). By slow evaporation, 3b was obtained as yellow crystals.
Mass spectra (EI-MS, 70 eV) m/z (rel int) = 624 (25) [M+],
547(100) [M+ꢁPh], 470(10) [M+ꢁ2PhꢁH], 438(50) [M+ꢁ2PhꢁH],
396(6) [Ph2PbSH2], 285(8) [PhPb+], 208(38) [Pb+]. Yield: 54%
(0.10 g, 0.16 mmol). M.p. 135–137 °C. Anal. Calc. for C24H16OPbS3,
C 46.21, H 2.59. Found: C 47.28, H 2.79%. 1H NMR (CDCl3):
Scheme 1.
protio-solvent signal used as referenced for 1H NMR spectra.
13C{1H} NMR spectra were referred through the solvent peaks.
Chemical shifts are quoted on the d scale (downfield shifts are po-
sitive) relative to tetramethylsilane (1H, 13C{1H} NMR spectra).
Spectra were recorded at 25 °C. 1H NMR spectra; 399.78 MHz,
13C{1H} NMR spectra; 100.53 MHz.
1
1
d = 7.39 (dd, 3JH
–
H
2 = 8.00 Hz, 4JH
–
3 = 2.00 Hz, 2H, H1), 7.26 (m,
–
H
6H, H5, H6, H7), 6.93 (dd, 3JH
–
H
1 = 3JH
3 = 8.00 Hz, 2H, H2), 6.77
H
2
2
3
3
(dd, 3JH
– –
1 = 8.00 Hz, 4JH 2 = 2.00 Hz, 2H, H3) ppm. 13C{1H}
H H
2.2. Synthesis of diphenyl lead organometallic compounds
NMR (CDCl3): d = 155.7 [1J(13Cꢁ207Pb) = 560 Hz, C5a], 150.0
[3J(13Cꢁ207Pb) = 39.2 Hz, C1a], 135.4 [2J(13Cꢁ207Pb) = 90.7 Hz, C5],
132.9 [3J(13Cꢁ207Pb) = 20.0 Hz, C2], 130.4 [3J(13Cꢁ207Pb) = 116.1 Hz,
C6], 130.0 [4J(13Cꢁ207Pb) = 26.1 Hz, C7], 126.3 [2J(13Cꢁ207Pb) =
26.1 Hz, C1], 124.7 [C3], 124.3 [C4], 120.7 [C4a] ppm. IR (KBr pellet,
cmꢁ1): 3059, 3037, 1566, 1469, 1431, 1401, 1223, 1197, 1055,
1011, 904, 872, 831, 770, 723, 686.
2.2.1. Synthesis of [{O(C6H4S)2}PbPh2] (1b)
n-BuLi in hexanes (1.6 M, 1.6 mL, 2.6 mmol) was added to a
solution containing O(C6H4SH)2 (1a, 0.27 g, 1.15 mmol) in THF
(40 mL) at 0 °C. After the solution was stirred for 30 min, was
slowly added a suspension of Ph2PbCl2 (0.50 g, 1.15 mmol) in
THF (30 mL). The suspension was dissolved, and the yellow solu-
tion obtained was stirred for 24 h at room temperature. The white
solid formed was filtered out and the solution dried by means of a
column of Celite and Na2SO4. The solvent was removed in vacuum.
The resulting yellow solid was dissolved in chloroform. By slow
evaporation 1b was obtained as yellow crystals. Yield: 66%
(0.45 g, 0.76 mmol). Mass spectra (EI-MS, 70 eV) m/z (rel
int) = 594 (5) [M+], 517(3) [M+ꢁPh], 439(8) [M+ꢁ2PhꢁH], 397(10)
[Ph2PbSH2+1], 285(8) [PhPb+], 200(10) [O(C6H4)2S+]. M.p. 115–
2.3. X-ray crystallography
Suitable single crystals of the compounds 1b, 2b (thin plates)
and 3b were grown by slow evaporation from a chloroform solu-
tion. X-ray diffraction data were collected at room temperature
on a CCD Smart 6000 diffractometer through the use of Mo K
a
radiation (k = 0.71073 Å, graphite monochromator). Data were
integrated, scaled, sorted, and averaged using the SMART software
package. The primary structure of 2b was solved by heavy atom
method using SHELXS86 [14] and the structures of 1b and 3b were
119 °C. Anal. Calc. for C24H18OPbS2 C, 48.55; H, 3.06. Found: C,
5
48.75; H, 3.12%. 1H NMR (CDCl3): d = 7.62 [d, 4H, 3JH
–
H
6 = 7.52 Hz,
3J(1Hꢁ207Pb) = 107 Hz, H5), 7.57 (m, 2H, H1), 7.40 (t, 4H,
6
3JH
6
– –
5 = 3JH 7 = 7.52 Hz, 4H H6), 7.29 (m, 2H, H7), 7.02 (m, 4H,
H H
H2 and H3), 6.82 (m, 2H, H4) ppm. NMR 13C{1H} (CDCl3):
Table 1
d = 157.5 [1J(13Cꢁ207Pb) = 535.8 Hz, C5a], 155.3 [3J(13Cꢁ207Pb) =
Selected crystallographic data for compounds 1b, 2b and 3b.
19.2 Hz,
C
4a], 135.7 [2J(13Cꢁ207Pb) = 93.8 Hz, C5], 135.1
Compound
1b
2b
3b
[3J(13Cꢁ207Pb) = 20.1 Hz, C1], 130.2 [3J(13Cꢁ207Pb) = 113.8 Hz, C6],
129.9 [4J(13Cꢁ207Pb) = 25.4 Hz, C7], 127.9 [2J(13Cꢁ207Pb) = 26.2 Hz,
Empirical Formula
Mr [g/mol]
C24H18OPbS2
593.69
C24H18PbS3
609.75
C24H16OPbS3
623.74
C
1a], 127.2 [C2], 124.4 [C3], 119.6 [C4] ppm. IR (KBr pellet, cmꢁ1):
Crystal size (mm)
Color
0.28 ꢂ 0.14 ꢂ 0.08 0.27 ꢂ 0.10 ꢂ 0.04 0.62 ꢂ 0.43 ꢂ 0.40
Yellow
Yellow
Yellow
3063, 1693, 1568, 1461, 1433, 1430, 1260, 11025, 1011, 968,
800, 755, 727, 691.
Crystal system
Space group
Triclinic
P1
1.796
Triclinic
P1
1.848
Triclinic
P1
1.844
ꢀ
ꢀ
ꢀ
qcalc (Mg mꢁ3
)
2.2.2. Synthesis of [{S(C6H4S)2}PbPh2] (2b)
Z
2
2
2
This compound was prepared in a similar fashion to compound
1b, with S(C6H4SH)2 (2a, 0.3 g, 1.2 mmol), n-BuLi in hexanes (1.6 M,
1.7 mL, 2.7 mmol) and Ph2PbCl2 (0.52 g, 1.2 mmol) in THF. By slow
evaporation 2b was obtained as yellow crystals and washed with
warm isopropanol. Yield: 68% (0.50 g, 0.82 mmol). Mass spectra
(EI-MS, 70 eV) m/z (rel int) = 610 (5) [M+], 533 (55) [M+ꢁPh], 456
(5) [M+ꢁPhꢁPh], 439 (20) [Ph3Pb+], 397 (5) [Ph2PbSH2+1], 285
(20) [PhPb+], 248 (65) [S(C6H4)2S2+], 216 (100) [S(C6H4)2S+]. M. p.
290–294 °C. Anal. Calc. for C24H18PbS3 C, 47.27; H, 2.98. Found: C,
a (Å)
b (Å)
c (Å)
9.806(1)
10.338(1)
11.044(1)
99.098(2)
96.601(2)
90.472(3)
1097.8(2)
7.886
9.946(4)
10.383(5)
11.354(5)
72.367(1)
79.010(9)
88.678(9)
1096.1(8)
7.989
9.115(1)
10.716(1)
12.460(2)
76.705(3)
71.498(3)
85.480(2)
1123.1(3)
7.802
a
(°)
b (°)
c
V
l
(°)
(mmꢁ1
)
F(000)
h Range (°)
Goodness-of-fit
Absorption
correction
Reflections
collected
Unique reflections,
Rint
R1, wR2 [I > 2
568
1.88–26.01
1.116
584
1.92–26.11
1.003
596
1.77–26.09
1.042
3
2
47.10; H, 3.05%. 1H NMR (CDCl3): d = 7.06 (dd, 3JH
–
=
SADABS
SADABS
SADABS
H
3
2
3
3JH
–
–
4 = 7.60 Hz, 4JH
–
H
1 = 1.40 Hz, 2H, H3), 7.20 (ddd,
H
2
2
13245
13633
13624
3JH
1 = 3JH
–
H
3 = 7.60 Hz, 4JH
–
4 = 1.40 Hz, 2H, H2), 7.33 (m, 2H,
H
H
H7), 7.44 (m, 6H, H4 y H6), 7.67 [m, 6H, H4 and H5 3J(1Hꢁ207Pb) =
4286, 0.0330
4338, 0.0970
4416, 0.0418
120 Hz]
ppm.
13C{1H}
NMR
(CDCl3):
d = 160.4
[1J(13Cꢁ207Pb) = 493.9 Hz, C5a], 141.8 [3J(13Cꢁ207Pb) = 34.6 Hz,
r(I)]
0.0315, 0.0724
0.0440, 0.0860
0.905, ꢁ0.614
0.0523, 0.1045
0.1016, 0.1311
1.273, ꢁ0.803
0.0337, 0.0736
0.0473, 0.0819
0.765, ꢁ0.708
4a], 137.0 [2J(13Cꢁ207Pb) = 24.6 Hz, C1a], 135.4 [2J(13Cꢁ207Pb) =
R1, wR2 (all data)
C
Large residuals
94.2 Hz, C5], 134.8 [3J(13Cꢁ207Pb) = 22.7 Hz, C1], 133.6 [C4], 130.3
[3J(13Cꢁ207Pb) = 107.6 Hz, C6], 129.8 [4J(13Cꢁ207Pb) = 25.8 Hz, C7],
(e Åꢁ3
)

S. González-Montiel et al. / Polyhedron 28 (2009) 467–472
469
4
solved by direct methods using SHELXTL NT Version 5.10 and re-
4a
S
fined by full-matrix least squares against F2 [15]. An empirical
absorption correction based on the multiple measurement of
equivalent reflections was applied by using the program SADABS
[16]. The displacement parameters of non-hydrogen atoms were
refined anisotropically. The positions of the hydrogen atoms were
kept fixed with a common isotropic displacement parameter. Se-
lected crystallographic data are given in Table 1.
3
2
4
3
4a
D
2
1a
O
1
1a
1
S
S
S
S
Pb
Pb
5a
5
5a
Ph
Ph
5
7
7
3. Results and discussion
6
6
(3b)
D = O (1b); S (2)b
3.1. Synthesis
Scheme 3.
The ligands O(C6H4SH)2 (1a), S(C6H4SH)2 (2a) and S(C6H3SH)2O
(3a) were prepared following the reported method [8,13,12]. The
compounds 1b and 2b were obtained from the reaction of Ph2PbCl2
in THF at 0 °C with the dilithium salt of 1a and 2a generated in situ,
yielding the corresponding Pb(IV) compounds as yellow crystals.
3b was obtained from the reaction of 3a with Ph2PbCl2 in hot
methanol (see Scheme 2). All compounds are air-stable, soluble
in chloroform, methylene chloride and benzene, and insoluble in
n-hexane, pentane, methanol and 2-propanol.
experiments (COSY, HETCOR and COLOC). In solution the two
DC6H4SPbPh [D = O (1b); S (2b)] and S(C6H3S)OPbPh (3b) halves
are equivalents.
3.2.1. 1H NMR spectra
In the spectra of title compounds, besides to the disappearance
of the signal of the SH protons of the free ligands O(C6H4SH)2
(d = 3.90 ppm), S(C6H4SH)2 (d = 4.10 ppm) and S(C6H3SH)2O (d =
4.05 ppm), is observed that the PbPh2 moiety deshields the ortho
protons to the thiolate sulfurs. Moreover, the protons 5-H in 1b
and 2b show coupling with the 207Pb isotope [3J(1Hꢁ207Pb) = 120
and 107 Hz for 1b and 2b, respectively]; in 3b the coupling constant
was not observed because the protons of the phenyl groups are dis-
played as a multiplet.
3.2. NMR spectra
NMR spectra of all the complexes were recorded in CDCl3 solu-
tions at room temperature and the chemical shifts are relatives to
TMS. The assignments of these compounds were performed by 2D
1) THF/n-BuLi
3.2.2. 13C{1H} NMR spectra
2) Ph2 PbCl2
In the 13C{1H} spectra of title compounds is observed 13C–207Pb
coupling, with one to four-bond coupling constants. Comparison of
13C data and coupling constants with other related compounds is
listed in Table 2, Scheme 3. The nJ(13C– 207Pb) coupling constant
diminishes in the order of C5a > C6 > C5 > C7 for the phenyl groups
in all compounds. The magnitude of the 1J(13C–207Pb) for the 5a
ipso-carbon is similar to some thiolate lead compounds with coor-
dination number four [6]. An increase in the coordination number
of Pb(IV) is observed when the one-bond 13C–207Pb coupling con-
stant and the chemical shift for the 5a ipso-carbon are increased;
in our compounds we conclude that the OꢀꢀꢀPb (1b and 3b) and
SꢀꢀꢀPb (2b) transannular interactions are very weak or completely
lacking in solution.
D
D
SH
HS
S
Ph
S
-2 LiCl
Pb
Ph
D = O ( 1 a)
D = S ( 2 a)
D = O ( 1 b)
D = S ( 2 b)
S
S
O
O
SH
HS
S
Ph
S
Ph
2PbCl2
Pb
-2 HCl
Ph
3.3. X-ray crystallographic studies
(3 a)
(3 b)
The crystal structures in crystalline solid state of the title com-
pounds were determined by single crystal X-ray diffraction analy-
Scheme 2.
Table 2
13C{1H} NMR chemical shift (d values in ppm), coupling constant [nJ(13C–207Pb) in Hz] for 1b, 2b, 3b and other related compounds.
Compound
C-1
C-2
C-3
C-4
C-1a
C-4a
C-5
C-5a
C-6
C-7
O(CH2CH2S)2PbPh2
135.6
158.7
129.9
129.2
a
2J = 88.4
135.8
3J = 109.3
129.9
4J = 19.1
129.3
S(CH2CH2S)2PbPh2
158.7
2J = 87.5
135.7
3J = 108.4
130.2
4J = 24.3
129.9
a
1b
2b
3b
135.1
127.2
128.2
124.4
126.9
124.7
119.6
133.6
124.3
127.9
155.3
157.5
3J = 20.1
134.8
2J = 26.2
137.0
3J = 19.2
141.8
2J = 93.8
135.4
1J = 535.8
160.4
2J = 113.8
130.3
4J = 25.4
129.8
3J = 22.7
126.3
2J = 24.6
150.0
3J = 34.6
120.7
2J = 94.2
135.4
1J = 493.9
155.7
3J = 107.6
130.4
4J = 25.8
130.0
132.9
2J = 26.1
3J = 20.0
3J = 39.2
2J = 90.7
1J = 558.9
3J = 116.1
4J = 26.1
a
The 1J(13C–207Pb) coupling constants are not reported by the authors [17].

470
S. González-Montiel et al. / Polyhedron 28 (2009) 467–472
Table 3
ses. The crystals of 2b were thin plates; this fact influenced the
quality of the collected data. The molecular drawings of 1b, 2b
and 3b are depicted in Fig. 1 and selected bond lengths, angles
and torsion angles are given in Table 3.
Selected bond lengths (Å), angles and torsion angles (°) for 1b, 2b and 3b.
Compound
[{O(C6H4S)2}PbPh2] [{S(C6H4S)2}PbPh2] [{S(C6H3S)2O}PbPh2]
1b
2b
3b
D
O1
S3
O1
DꢀꢀꢀPb1
3.053(4)
2.531(2)
2.536(2)
2.201(6)
2.211(6)
112.0(1)
123.8(2)
104.9(2)
97.4(2)
112.0(2)
105.9(2)
118.1(4)
150.0(2)
85.7(2)
3.280(3)
2.531(3)
2.521(3)
2.21(1)
2.21(1)
106.5(1)
114.8(4)
120.3(3)
105.4(3)
108.1(3)
99.5(3)
101.9(5)
161.9(3)
82.9(3)
65.73(9)
132.9(9)
ꢁ62.8(10)
92.9(4)
ꢁ7.4(4)
3.113(4)
2.519(2)
2.522(2)
2.198(6)
2.198(6)
115.08(6)
121.2(2)
104.9(2)
107.1(2)
101.8(2)
107.1(2)
117.7(4)
90.7(2)
148.0(2)
63.29(8)
142.8(5)
ꢁ141.6(5)
ꢁ78.6(2)
78.7(2)
Pb1–S1
Pb1–S2
Pb1–C13
Pb1–C19
S1–Pb1–S2
C13–Pb1–C19
S1–Pb1–C13
S1–Pb1–C19
S2–Pb1–C13
S2–Pb1–C19
C6–D-C7
D ? Pb1–C19
D ? Pb1–C13
D ? Pb1–S1
C1–C6–D–C7
C12–C7–D–C6
65.31(8)
80.0(7)
ꢁ151.7(5)
S1–Pb1–S2–C12 1.7(2)
S2–Pb1–S1–C1
ꢁ80.2(2)
3.3.1. Molecular structures
All lead–carbon bond distances agree very well with the corre-
sponding covalent radii sum [18]. The lead–sulfur distances also
agree with those reported in compounds containing the kernel
S2PbPh2 into a cyclic system [19–22]. The bond angles around
the central lead atom are quite different from the tetrahedral an-
gles. In particular, the S1–Pb1–S2 and C13–Pb1–C19 bond angles
in 2b are the smallest. This difference in angles causes a distortion
in the tetrahedron formed by the S1, S2, C13 and C19 vertices
enclosing the coordination sphere of the lead atom.
In addition to the four covalent bonds expected for a lead (IV)
compound, a relatively short distance involving the transannular
D and Pb atoms is observed in the three compounds. The OꢀꢀꢀPb
lengths in 1b [3.053(4) Å] and 3b [3.113(4) Å] are shorter than
the van der Waals radii sum [
and 42% longer than the covalent radii sum [
R
rvdW(O,Pb) = 3.54 Å] [23], but 39
rcov(O,Pb) = 2.20 Å]
R
[24]. These distances are longer than those reported for the more
flexible plumbocane [{O(CH2CH2S)2}PbPh2] contained in two poly-
morphs [OꢀꢀꢀPb = 2.855(5) and 2.888(6) Å in the orthorhombic sys-
tem; 2.92(1) and 3.08(1) Å in the triclinic system] [18] and in
Ph3PbSOCC6H4Me [2.990(4) Å] [7]. Likewise, the distance SꢀꢀꢀPb in
2b [3.280(3) Å] is also less than the corresponding van der Waals
radii sum [RrvdW(S,Pb) = 4.1 Å] [23] and comparable to distances
reported for compounds containing anisobidentate ligands [2.941
and 2.958 Å in {(PhCH2O)2PS2}2PbPh2] [25]; 3.017 Å in (Ph2PS2)2-
PbPh2 [26]. The magnitude of these intramolecular DꢀꢀꢀPb interac-
tions are consistent with a secondary bonding.
The molecular structures of the 1b and 2b compounds are sim-
ilar, despite the presence of different donors atoms (O versus S). On
the other hand, there are marked differences between the struc-
tures of the 1b and 3b compounds with oxygen as a donor atom;
in 1b the eight-membered ring conformation can be described as
a twist boat (C1 symmetry), while in 3b the ring conformation
can be described as boat–chair (Cs symmetry), according to the tor-
sion angles listed in the Table 3. In regard to these conformations,
it is normally accepted that just the first conformation is consistent
with a transannular interaction. These results show the flexibility
2ꢁ
of the DðC6H4SÞ [D = S and O] and SðC6H3SÞ O2ꢁO potentially tri-
Fig. 1. Molecular structures of [{O(C6H4S)2}PbPh2] (1b), [{S(C6H4S)2}PbPh2] (2b)
and [{S(C6H3S)2O}PbPh2] (3b).
2
2
dentate ligands in order to adopt different arrangements.

S. González-Montiel et al. / Polyhedron 28 (2009) 467–472
471
Fig. 2. The crystal packing of compound 1b. (a) Intermolecular hydrogen bonds (C–HꢀꢀꢀO) showing the dimeric associations. (b) Arrangement of the
p
-stacking interactions
type offset-stacked and face-tilted-T.
Fig. 3. The crystal packing of compound 2b. (a) The intra and intermolecular interactions SꢀꢀꢀPb, showing the hexacoordinated lead atom. (b) Arrangement of the
intermolecular hydrogen bonds in (C–HꢀꢀꢀS) and the -stacking interactions.
p
Fig. 4. The crystal packing of compound 3b. Arrangements of the different p-stacking interactions type offset-stacked.
In order to compare the magnitude of the transannular interac-
for 1b, 0.077 for 2b and 0.052 for 3b, respectively. The BO calculated
indicates that sulfur is a better donor than the oxygen atom towards
lead, however, in all cases the DꢀꢀꢀPb transannular interaction is
weak.
tion in all compounds, the Pauling-type bond order (BO) [27,28] has
P
expꢁ
rcovÞꢃ
been calculated, according to the formula BO ¼ 10ꢁ½1:41ðd
,
where dexp is the DꢀꢀꢀPb transannular distance. The BO are 0.063

472
S. González-Montiel et al. / Polyhedron 28 (2009) 467–472
Considering the four covalent bonds and the secondary interac-
free of charge via http://www.ccdc.cam.ac.uk/conts/retriev-
ing.html, or from the Cambridge Crystallographic Data Centre, 12
Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223 336 033; or
e-mail: deposit@ccdc.cam.ac.uk. Supplementary data associated
with this article can be found, in the online version, at
doi:10.1016/j.poly.2008.11.012.
tions DꢀꢀꢀPb, the Pb atom in all compounds is penta-coordinated
with a coordination sphere geometry described as monocapped
tetrahedral, where the D donor atom (O for 1b and 3b; S for 2b)
is capping the tetrahedron. This proposal is supported by the short
displacement percent from tetrahedral to trigonal bipyramidal
geometry calculated for the compounds according to the procedure
of Holmes based upon donor-acceptor atom bond length [29–31].
The tetrahedral distortion calculated is 48% for 1b, 51% for 2b
and 45% for 3b.
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3.3.2. Crystal structures
The crystal packing of title compounds is stabilized by several
non-bonded interactions.
In 1b the molecules are associated by weak hydrogen bonding
C–HꢀꢀꢀO as well as offset-stacked parallel – displaced and face-
tilted-T aromatic interactions [32]. In this compound, the lead
atom is not involved in intermolecular interactions (Fig. 2).
In the crystal structure of 2b is observed the presence of mole-
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p-stacking interac-
tions (Fig. 3).
If both transannular and intermolecular SꢀꢀꢀPb interactions are
considered, then the lead atom is hexacoordinated, and its geome-
try can be described as bicapped tetrahedral.
In the crystal structure of 3b, only are present dimeric building
blocks self-assemble into chains via
p-stacking interactions be-
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4. Conclusions
In order to study the phenomena of hypercoordination in
organolead compounds we have synthesized and structurally char-
acterized three new diphenyllead(IV) compounds by employing
efficient tridentate ligands. In the solid state, the compounds dis-
play a distorted tetrahedral local geometry at Pb(IV) center. In view
of the above findings and previous results, we conclude that, for a
given PbPh22þ fragment, the more flexible ligand DðC6H4SÞ (D = O,
2ꢁ
2
S) is able to show a weak interaction, leaving without change the
[24] W.W. Porterfield, Inorganic Chemistry:
Academic Press Inc, USA, 1993. p. 214.
A Unified Approach, second ed.,
conformation of the eight-membered ring, and displaying a triden-
tate coordination mode. On the other hand, the more rigid ligand
S(C6H3S)2O2ꢁ displays a bidentate coordination mode, with a to-
tally different conformation that avoids any transannular
interaction.
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Acknowledgments
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BFC fully acknowledges the scholarship from CONACyT. This re-
search was supported by CONACyT (Project 44009).
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Appendix A. Supplementary data
CCDC 704628, 704629 and 704630 contain the supplementary
crystallographic data for 1b, 2b and 3b. These data can be obtained