Synthesis and structural characterization of palladium and platinum bimetallic compounds derived from bidentate P, S-palladacycle metaloligands

Article abstract of DOI:10.1021/cg901111u

Treatment of 4-MeOC₆H₄C(Me)=NN(H)C(=S)NHMe (1), with potassium tetrachloropalladate gave the tetranuclear compound [Pd{4-MeOC ₆H₃C(Me)=NN=C(S)NHMe}]₄ (2), with the ligand as terdendate [C,N,S]. Reacti

Full text of DOI:10.1021/cg901111u

DOI: 10.1021/cg901111u
Synthesis and Structural Characterization of Palladium and Platinum
Bimetallic Compounds Derived From Bidentate P,S-Palladacycle
Metaloligands
2010, Vol. 10
700–708
†
Jose M. Antelo, Luis Adrio, M. Teresa Pereira, Juan M. Ortigueira,
†
†
ꢀ
ꢀ
‡
Jesus J. Fernandez, and Jose M. Vila*
,†
ꢀ
ꢀ
†
´
Departamento de Quımica Inorganica, Universidad de Santiago de Compostela,
15782 Santiago de Compostela, Spain and Departamento de Quımica Fundamental,
ꢀ
‡
´
Universidad de A Corun~a, 15071 A Corun~a, Spain
Received September 10, 2009; Revised Manuscript Received November 30, 2009
ABSTRACT: Treatment of 4-MeOC6H4C(Me)dNN(H)C(dS)NHMe (1), with potassium tetrachloropalladate gave the
tetranuclear compound [Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}]4 (2), with the ligand as terdendate [C,N,S]. Reaction of
2 with the diphosphines Ph2PCH2PPh2 (dppm), Ph2PC(dCH2)PPh2 (vdpp), and Ph2PC(CH2)2PPh2 (dpcp) gave the mono-
nuclear complexes [Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}(L)] (L = dppm-P, 3; dpcp-P, 4; vdpp-P, 5) with the dipho-
sphine ligand binding in a monodentate fashion. Compounds 3-5 may bond systematically to a second metal atom, palladium
or platinum, through the noncoordinated phosphorus atom and the sulfur atom of the thiosemicarbazone moiety to give the
dinuclear compounds 6-10, thus behaving as bidentate P,S-palladacycle metaloligands. All the compounds have been
characterized by elemental analysis, and by IR and NMR spectroscopy; and the crystal and molecular structures of 1, 2,
6-10 have been determined by X-ray crystallography. Inter- and intramolecular hydrogen bonding in the solid results in crystal
self-organization leading to chains and/or layers in the molecular array.
Introduction
feature of thiosemicarbazones, and of their ensuing com-
pounds, is the ability to display intermolecular hydrogen
bonding, the latter being important in molecular and crystal
organization; also, hydrogen bonding in thiosemicarbazones
and their complexes is important given the biologically acti-
vity of these materials.21-23 In the ligands the CdS and NH
groups are capable of forming eight-membered (CSNH)2
The chemistry of cyclometalated compounds, and in parti-
cular that of palladacycles, has come to be a most interesting
part of organometallic chemistry, with many reviews covering
this subject.1-12 They exhibit a good number of applications
that range from the synthesis of new organic and organo-
metallic compounds, to mesogenic species and catalytic
materials.13-16 In particular, thiosemicarbazones produce
tetranuclear compounds with two distinct palladium-sulfur
bonds, that is, Pd-Schelating and Pd-Sbridging, binding tightly
to the metal as terdentate [C,N,S] and when treated with
tertiary diphosphines in the resulting compounds the metal
atom is bonded to only one phosphorus atom; the strength of
the Pd-Schelating bond prevents the chelating bidentate mode
of the diphosphine ligand.17,18 Because the sulfur atom may
undergo further coordination, the ensuing moieties behave as
bidentate P,S-palladacycle metaloligands. However, coordi-
nation through phosphorus alone may be achieved with
metals having only one available coordination site, and we
haverecently reportedthe firstanalogousplatinacyclemetalo-
ligand from a furane thiosemicarbazone, where reaction
with an iron pentacarbonyl moiety gives a bimetallic species
with the second metal only bonded to the phosphorus atom.19
Previous bimetallics bearing palladacycle P,S-metaloligands
have been limited to the use of only the short-bite diphosphine
Ph2PCH2PPh2 (dppm);20 therefore, to widen the scope of
our research we have extended the bimetallic systems to
include those with 1,1-bis(diphenylphosphine)ethene, Ph2PC-
(dCH2)PPh2 (vdpp), and 1,1-bis(diphenylphosphine)cyclo-
propane, Ph2PC(CH2)2PPh2 (dpcp), as well as including the
mixed palladium/platinum species. Furthermore, a salient
rings, through a pair of N-H S hydrogen bonds, having
3 3 3
two donors and two acceptors. Additional hydrogen bonding
may appear between the sulfur atom and a neighboring
methyl group, C-H S, to give seven-membered rings,24
3 3 3
as well as intramolecular hydrogen bonds. The eight-
membered (CSNH)2 ring may also be portrayed in the
corresponding compounds,24 or it may be absent when other
electronegative atoms favor formation of hydrogen bonding
withthe thioamideNH group, asfor example when a methoxy
substituent is present, which results in the development of
polymeric chains based on N-H O bonds; analogous
3 3 3
situations may arise if halogen atoms from M-X bonds or
solvent molecules are present.
Therefore, along with the first palladium-platinum bime-
tallic compounds derived from bidentate P,S-palladacycle
metaloligands, herein we report the structures of the thiose-
micarbazone ligand, and of di- and tetranuclear complexes
depicting the crystal self-organization which is displayed as a
consequence of the differing hydrogen bonds.
Results and Discussion
The sequence of reactions leading to the precursor mono-
nuclear compounds 3-5 can be viewed in Scheme 1 (see
Experimental Procedures for characterizing data). The new
homo- and heterobimetallic complexes 6-10 were prepared
byadding [PdCl2(NCPh)2] or [PtCl2(NCPh)2], asappropriate,
in a 1:1 molar ratio to a solution of the corresponding
*To whom correspondence should be addressed. Fax: þ34/981595012.
E-mail: josemanuel.vila@usc.es.
r
pubs.acs.org/crystal
Published on Web 01/05/2010
2010 American Chemical Society

Article
Crystal Growth & Design, Vol. 10, No. 2, 2010 701
Scheme 1. (i) K2[PdCl]4/EtOH/H2O; (ii) Ph2PRPPh2/acetone;
(iii) MCl2(NCPh)2/acetone
compounds 3-5; they are air-stable solids, with the ligand in
the (E,Z) configuration (Experimental Procedures and
Scheme 1). The second metal is bonded via the phosphorus
and sulfur atoms in a dimetallic six-membered chelate ring.
The complexes are soluble in CHCl3, CH2Cl2, DMSO, and
acetone, but insoluble in MeOH, EtOH, and water.
Molecular and Crystal Structures of 6-10. Crystals were
monoclinic, with space groups 6, 8 CH2Cl2 (P121/c1), 7
(C12/c1), 9, 10 CH2Cl2 (P21/c). The most significant para-
3
3
meters for these compounds are shown in Tables 1 and 2 (7,
9, 10 CH2Cl2 Figures 1 and 2; 6, Supporting Information,
Figure S1, 8 CH2Cl2, Supporting Information, Figure S2).
3
3
The metal atoms show distorted square-planar environ-
ments, with the distortion most noticeable in the Pd(2) or
Pt atoms, due to the greater rigidity imposed by the thiose-
micarbazone ligand on the Pd(1) atom, and to the presence of
terminal chloride ligands on the second metal, which en-
hances vibration during the crystallographic measurement
process.
All bond lengths are within the expected range, with
allowance for the strong trans influence of the phosphorus
donor ligand,18 which is reflected in the Pd(1)-N(1) distance
of 2.020(4)-2.036(11) A [cf. sum of the covalent radii for
Table 1. Crystal Data for 6, 7, 8 CH2Cl2, 9, and 10 CH2Cl2
3
3
6
7
8 CH2Cl2
9
10 CH2Cl2
3
formula
C36H35Cl2N3O-
P2Pd2S
903.37
C38H37Cl2N3O-
P2Pd2S
929.41
C38H37Cl4N3O-
P2Pd2S
1000.31
C36H35Cl2N3O-
P2PdPtS
992.06
C38H37Cl4N3O-
P2PdPtS
1089.00
M
crystal system
space group
a (A)
b (A)
c (A)
monoclinic
P121/c1
monoclinic
C12/c1
monoclinic
P121/c1
monoclinic
P21/c
monoclinic
P21/c
8.984(1)
16.724(2)
27.058(3)
98.387(2)
4021.6(8)
4
18.112(3)
12.157(2)
16.295(2)
105.503(2)
3457.4(9)
4
47.44(1)
9.832(2)
18.287(5)
93.010(5)
8518(4)
8
1.125
0.86-18.52°
SADABS
3182
8.942(2)
16.756(3)
27.091(5)
98.452(4)
4014.9(13)
4
1.329
1.52-26.44°
SADABS
18.163(3)
12.247(2)
16.669(3)
105.957(3)
3565.0(10)
4
β (°)
V (A3)
Z
μ (mm-1
)
1.383
4.757
4.354
theta range for collection
absorption correction
unique reflections, R
R(int)
1.17-28.35°
SADABS
8382 R(int)=0.0454]
0.0454
2.03-26.4°
SADABS
7263 [R(int)=0.0652]
0.0652
1.44-28.31°
SADABS
9694 [R(int)=0.0443]
0.0443
8218 [R(int)=0.0844]
0.0844
0.0995
data/restraints/parameters
goodness-of-fit
8382/0/431
1.135
0.0366
0.1028
0.883 and 0.780
1.418 and -0.904
3182/36/433
0.964
0.0545
0.1512
1 and 0.549
0.809 and -0.621
8218/0/460
1.014
0.0458
0.1146
0.887 and 0.866
0.805 and -0.742
7263/0/427
1.075
0.0393
0.097
0.717 and 0.509
0.826 and -1.18
9694/0/463
1.106
0.0343
0.0738
0.647 and 0.512
0.866 and -1.007
R [F, I > 2σ(I)]
wR[F2, all data]
max and min transmission
largest diff peak and hole (e A)-3
3
˚
Table 2. Selected Bond Lengths (A) and Angles (°) in 1, 2, 6, 7, 8 CH2Cl2, 9, and 10 CH2Cl2
3
3
1
2
6
7
8 CH2Cl2
3
9
10 CH2Cl2
3
C(6)-Pd(1)
N(1)-Pd(1)
S(1)-Pd(1)
Pd(1)-P(1)
S(1)-M(2)
P(2)-M(2)
M(2)-Cl(1)
M(2)-Cl(2)
C(7)-N(1)
N(1)-N(2)
N(2)-C(8)
C(8)-S(1)
2.014(7)
1.994(6)
2.364(2)
2.038(4)
2.027(3)
2.334(1)
2.258(1)
2.303(1)
2.248(1)
2.343(1)
2.339(1)
1.292(5)
1.383(5)
1.303(5)
1.809(4)
1.955(17)
2.036(11)
2.255(4)
2.255(4)
2.312(3)
2.281(3)
2.330(4)
2.321(4)
1.294(18)
1.382(16)
1.258(16)
1.832(16)
2.023(6)
2.026(5)
2.334(2)
2.026(5)
2.257(2)
2.257(2)
2.340(2)
2.321(2)
1.295(8)
1.381(7)
1.293(8)
1.809(6)
2.038(7)
2.025(6)
2.334(2)
2.264(2)
2.296(2)
2.228(2)
2.343(2)
2.333(2)
1.308(9)
1.394(8)
1.280(9)
1.808(7)
2.023(5)
2.020(4)
2.334(1)
2.259(1)
2.299(1)
2.234(1)
2.346(1)
2.327(1)
1.303(7)
1.383(6)
1.296(7)
1.810(6)
1.287(4)
1.376(3)
1.365(4)
1.672(3)
1.309(8)
1.381(8)
1.300(9)
1.777(8)
C(6)-Pd(1)-N(1)
N(1)-Pd(1)-S(1)
S(1)-Pd(1)-P(1)
C(6)-Pd(1)-P(1)
S(1)-M(2)-Cl(1)
Cl(1)-M(2)-Cl(2)
Cl(2)-M(2)-P(2)
S(1)-M(2)-P(2)
81.5(3)
82.85(17)
80.97(15)
82.89(10)
95.15(4)
100.98(12)
94.35(4)
89.35(4)
91.37(4)
86.70(4)
81.0(7)
83.5(5)
96.94(13)
98.6(6)
91.26(13)
88.38(14)
89.67(13)
90.08(12)
81.1(2)
80.6(3)
82.86(18)
94.70(7)
101.8(2)
93.60(7)
87.69(8)
91.78(8)
87.90(7)
81.2(2)
83.28(16)
97.09(6)
98.38(17)
93.26(6)
89.59(6)
87.86(6)
88.92(6)
83.34(13)
96.73(5)
98.63(15)
93.02(5)
87.74(5)
89.36(5)
89.57(5)

702 Crystal Growth & Design, Vol. 10, No. 2, 2010
Antelo et al.
palladium and nitrogen, 2.01 A25]. The C(8)-S(1) (1.808(7)-
1.832(16) A) and N(2)-C(8) (1.258(16)-1.303(5) A) bond
lengths show increased single and double bond character,
respectively, consequent upon deprotonation of the hydrazynic
NH group (Table 2). As for the second metal the differing trans
influences of the phosphorus, P(2), and sulfur atoms, S(1), is
put forward in the slightly longer M(2)-Cl(1) bond distance as
compared to M(2)-Cl(2). The Cremer-Pople parameters26
(Supporting Information Table T1) show the six-membered
bimetallic ring in a boat conformation, except in 9 where the
situation is intermediate between boat and twist-boat. The
metal coordination planes (C6, N1, S1, P1) and (P2, S1,
Cl1, Cl2) are essentially planar, and at an angle of 71.64(6)-
Compounds 6 and 9, are isostructural, hence displaying
nearly identical cell parameters; the asymmetric units con-
tain one molecule of the dinuclear compound. The
N-H O parameters for the interactions between mole-
3 3 3
cules for 6 [N(3)-H(3N) O(1)#: 0.780, 2.483, 3.247 A,
3 3 3
166.54°; #: x, y - 1, z] and for 9 [N(3)-H(3) O(1)#: 0.859,
3 3 3
2.417 3.247 A, 162.64°; #: x, 1 þ y, z] suggest close contacts28
between the methoxy group and the amide group,
which contribute to formation of chains along the b axis
(Figure 3a). Furthermore, besides the N-H O interac-
3 3 3
tions, and other minor intramolecular contacts involving the
hydrazinic nitrogen atom [6: C(11)-H(11A) N(2): 0.960,
3 3 3
2.344, 2.776 A, 106.65°; 9: C(11)-H(11C) N(2): 0.960,
3 3 3
75.47(7)°. The M M distance within the ring is greater than
2.348, 2.777 A, 106.44°], interactions between a chlorine
atom with CH groups from the phosphine phenyl rings
produce interweaving of the b axis chains along the c axis
(Figure 3b), leading to a two-dimensional network of mole-
3 3 3
the sum of the van der Waals radii27 in all cases, precluding any
metal-metal interaction.
In compound 7, the cyclopropane ring and phosphine
planes, C(24)-C(25)-C(26) and P(1)-C(24)-P(2), respec-
tively, are at an angle of 86.41°.
cules on the bc plane [6: C(23)-H(23) Cl(1)#: 0.930,
3 3 3
2.599, 3.461 A, 154.30°, #: x, 1/2 - y, -1/2 þ z; 9: C(13)-
H(13) Cl(1)#: 0.931, 2.667, 3.497 A, 148.92°; #: x, 1/2 - y,
3 3 3
1/2 þ z]. Additional C-H Cl interactions produce pairs of
3 3 3
sheets along the ac plane [6: C(2)-H(2) Cl(1)#: 0.931,
3 3 3
2.746, 3.657 A, 166.23°; #: 1 - x, 1 - y, 2 - z; 9: C(2)-
H(2) Cl(1)#: 0.929, 2.823, 3.721 A, 162.78°; #: -x, -y, -z]
3 3 3
(Figure 4); in each pair the phosphine phenyls are orientated
toward the outer part of the structure. Furthermore, there
are C-H π contacts29,30 between the a phosphine phenyl
3 3 3
and C-H atoms of neighboring molecules from adjacent
sheet pairs, at a H centroid distance of about 2.6 A, that
give rise to the environment for the structure that is repre-
sented in Figure 5.
As for compounds 8 CH2Cl2 and 10 CH2Cl2, they are
3 3 3
3
3
also isostructural and the asymmetric unit contains one
molecule of the dinuclear compound and dichloromethane
molecule; the presence of dichloromethane solvent mole-
cules in the crystal lattice produces an altogether different
picture for these two compounds as compared to compounds
6 and 9 that merits further comment. Thus, hydrogen bond-
ing interactions involving the solvent molecules, as well
as the methoxy and the amide groups [8 CH2Cl2: N(3)-
Figure 1. Crystal structure for complex 7. Ellipsoids are shown at
the 30% probability level.
3
H(3A) Cl(1S)#: 0.860, 2.771, 3.582 A, 157.80°; #: 2 - x,
3 3 3
Figure 2. Crystal structure for 9 and 10. Ellipsoids are shown at the 30% probability level.

Article
Crystal Growth & Design, Vol. 10, No. 2, 2010 703
Figure 3. View of 6 showing the formation of chains along the (a) b axis; (b) c axis.
Figure 4. View of 6 showing the formation of antiparallel chains
along the bc plane.
1 - y, 1 - z; C(25)-H(25B) O(1)#: 0.933, 2.583, 2.362 A,
3 3 3
Figure 5. Structure of 6 along the ac plane.
141.44°; #: 1 þ x, y, z; C(38)-H(38A) Cl(1)#: 0.970, 2.678,
3 3 3
3.421 A, 133.77°; #: 1 - x, 1 - y, 1 - z; 10 CH2Cl2: N(3)-
3
H(3N) Cl(1S)#: 0.860, 2.769, 3.589 A, 159.79°; #: -x, 2 þ y,
(H centroid <3.0 A) type, to give parallel zigzagging planes
3 3 3
3 3 3
-z; C(1S)-H(1S) Cl(1)#: 0.971, 2.708, 3.456 A, 134.27°;
(light blue and red lines), perpendicular to the bc plane, with the
chains on the edges and the separation between planes lodging
the aforementioned channels.
3 3 3
#: 1 - x, 2 þ y, -z; C(25)-H(25B) O(1)#: 0.931, 2.581,
3 3 3
3.350 A, 140.31°; #: -1 þ x, y, z] (Figure 6) produce sets of
antiparallel chains along the a axis, with channels running
through the face-to-face solvent molecules (Figure 7). Further-
The asymmetric unit of 7 also contains solvent molecules,
although in this case the quality of the diffraction data did not
allow the position of this molecule to be resolved clearly. As a
result in this case the solvent was removed from the structure
using SQUEEZE program31 implemented in PLATON.32,33
more, π-π and CH π interactions (Figure 8a) produce
3 3 3
additional short contacts29,30 between the phosphine phenyls
(light blue and red lines in Figure 8b), of the C-H
π
3 3 3

704 Crystal Growth & Design, Vol. 10, No. 2, 2010
Antelo et al.
Figure 6. View of 10 CH2Cl2 along the a axis.
3
Figure 7. Structure of 10 CH2Cl2 along the ab plane, showing the arrangement of the antiparallel chains.
3
Molecular and Crystal Structures of 1 and 2. The most
significant parameters for these compounds are shown in
Tables 2 and 3. Compound 1 crystallizes in the monoclinic
P21/n space group as the E,Z isomer relative to the N(1)-C(7)
and N(3)-C(8) bonds, respectively, typical of thiosemicarba-
zones where hydrogen bonding is present. For 1, a supramole-
cular structure based on dimers linked by a (CSNH)2 ring
R = 2.65°; β = γ = 11.82°, sym code: 1/2 - x, 1/2 - y, z]; there
are intermolecular hydrogen bonds between the methoxy and
the amide groups [N(3)-H(3N) O(1)#, 0.861, 2.117, 2.954 A,
163.93°, #: 1/2 þ x, -y, 1/2 þ z] that produce the tridimen-
sional growth of the crystal lattice (Figure 11). When viewed
along the ab plane, this produces a strikingly beautiful
crystal array with alternating square and cross-shaped cavities
(Figure 12; Supporting Information, Figure S4, view along the
a axis).
3 3 3
and by N-H O bonding was found. The two monomers in
3 3 3
each dimer are linked by a nonplanar (CSNH)2 ring through
N-H S bonds [1: N(2)-H(2) S(1)#: 0.860, 2.825,
IR Spectroscopy. The IR spectrum of the ligand showed
the typical υ(N-H)amide, υ(N-H)hydrazinic, υ(CdN), and
υ(CdS) stretches at 3367, 3191, 1608, and 836 cm-1, respec-
tively. Comparison of the spectra of the compounds with
that of the free ligand shows the disappearance of the
υ(N-H)hydrazinic and υ(CdS) bands. Both these observa-
tions are consistent with deprotonation of the NH group and
with loss of the double bond character of the CdS group; the
latter feature is confirmed in the crystal structures by the
lengthening of the C-S bond. The position of the
υ(N-H)amide stretch in the complexes shows that this group
is uncoordinated to the metal atom. The υ(CdN) stretch
shifts to lower wavenumbers upon complex formation
ca. 30 cm-1, suggesting coordination of the metal through
the nitrogen lone pair.34-36 The IR spectra of complexes
6-10 also include two υ(Pd-Cl) or υ(Pt-Cl) bands, with the
one trans to the phosphorus atom appearing at lower
wavelengths ca. 295 cm-1, in agreement with the greater
trans influence of the phosphorus atom, and the M-Cl
3 3 3
3 3 3
3.429 A, 128.70°; #: 2 - x, -y, -z] (Figure 9).
The molecule seems to be essentially planar with the
phenyl ring and the C(7)-N(1)-N(2)-C(8)-N(3) group
making an angle of 11.62°. The dimers are linked end-
to-end by N-H O bonds involving the methoxy group
3 3 3
[1: N(3)-H(3) O(1)#: 0.861, 2.465, 3.141 A, 136.04°; #1:
3 3 3
5/2 - x, 1/2 þ y, -2 - 1/2 - z]; this results in two mutually
perpendicular layouts of parallel dimers running along the
c axis in opposite directions (Supporting Information,
Figure S3 for the structure of 1). Any resemblance to the ligand
arrangement in the solid is lost in the ensuing compounds
because the sulfur atom is involved in bonding to the metal.
The tetranuclear compound 2 crystallizes in the tetragonal
P42/n space group; the asymmetric unit comprises a meta-
lated thiosemicarbazone ligand. Within each molecule, the
metalated moieties are displayed as two perpendicular sets of
nearly coplanar antiparallel pairs separated by about 3.6 A
(Figure 10). Compound 2 shows intramolecular π-π inter-
actions between the parallel metalacycles [dcentroids = 3.435 A,
stretch trans to sulfur ca. 310 cm-1
.

Article
Crystal Growth & Design, Vol. 10, No. 2, 2010 705
Figure 9. Structure of the ligand showing hydrogen bonding inter-
actions.
Figure 10. View of 2 along the b axis.
Figure 8. Compound 10 CH2Cl2. (a) Chain formation through
π-π and CH π interactions. (b) View of one layer of the parallel
zig-zaging environment, on the bc plane. (c) View down the a axis.
3
3 3 3
Table 3. Structural Data for 1 and 2
1
2
formula
M
crystal system
space group
a (A)
C11H15N3OS
237.32
monoclinic
P21/n
7.971(2)
5.468(2)
27.726(8)
94.583(6)
1204.6(6)
4
C44H52N12O4Pd4S4
1366.82
tetragonal
P42/n
13.078(1)
13.078(1)
14.998(3)
90
2565.1(5)
2
1.596
2.07-24.74°
SADABS
2203
Figure 11. Crystal structure of 2. Hydrogen atoms are omitted for
clarity [expect N3-H3]. Ellipsoids are shown at the 30% probabil-
ity level.
b (A)
c (A)
protons AA0XX0 spin system absent in the spectra of the
complexes. This is consistent with deprotonation37-40 of
both groups, and confirms metalation of the C6 carbon
atom. The three remaining phenyl proton resonances were
unequivocally assigned. The H5 resonance is coupled to the
metalated phenyl ring protons and also to the 31P nucleus in
3-10, and is shifted toward lower frequency with respect to
the spectrum of the ligand. In the bimetallic compounds the
PCH2P signal (in 6 and 9) is an apparent triplet for the proton
part of the approximately AA0XX0 system, with an N value
of about 22 Hz, and the vinylidene proton resonances of
vdpp (in 8 and 10) are two doublets of doublets ca. 6.5-6.1
by coupling to both 31P nuclei. Also, in complexes 3-10 the
MeO signal is upfield shifted by influence of the phosphine
phenyl ring currents, and the NHMe is strongly shifted to
higher field by about 2.4 ppm.
β (°)
V (A3)
Z
μ (mm-1
)
0.252
theta range for collection
absorption correction
unique reflections
Rint
data/restraints/ parameters 2437/0/145
GOF
2.72-26.4°
SADABS
2437
0.0517
0.0619
2203/0/154
1.145
0.0372
0.1068
0.852 and 0.780
0.95
0.0508
0.1496
0.987 and 0.924
R[F, I > 2σ(I)]
wR[F2, all data]
max and min transmission
largest diff peak and
0.262 and -0.288 0.716 and -0.506
hole (e A-3
)
3
1
NMR Spectroscopy. The main modifications in the H
NMR spectra of the ligand upon formation of the complexes
are the disappearance of the NH (8.58 ppm) and of the C(6)H
(7.63 ppm) resonances, the latter being part of the phenyl
The 31P NMR spectra consist of two doublets for the two
inequivalent phosphorus nuclei, for compounds 3-5 as well

706 Crystal Growth & Design, Vol. 10, No. 2, 2010
Antelo et al.
Mercury 300 spectrometer operating at 300.14 MHz using 5 mm o.d.
tubes; chemical shifts, in ppm, are reported downfield relative to TMS
using the solvent signal (CDCl3, δ 1H = 7.26 ppm) as reference. 31
P
NMR spectra were recorded at 202.46 MHz on a Bruker AMX 500
spectrometer using 5 mm o.d. tubes and are reported in ppm relative to
external H3PO4 (85%). Coupling constants are reported in Hz. Mass
spectra were recorded on a Katros MS50TC spectrometer connected
to a DS90 system and operating in the FAB mode (m-nitrobenzyl
alcohol, Xe, 8 eV; ca. 1.28 ꢀ 1015 J); ions were identified by DS90
software, and the data characterizing peaks for the metalated species
were calculated using the 106Pd and 196Pt isotopes. The physical
measurements were carried out by the RIAIDT services of the
Universidad de Santiago de Compostela.
4-MeOC6H4C(Me)dNN(H)C(dS)NHMe (1). 4-Methoxiaceto-
phenone (714 mg, 4.75 mmol) and hydrocloric acid (35%, 0.65 cm3)
were added to a suspension of 4-methyl-3-thiosemicarbazide
(500 mg, 4.75 mmol) in water (40 cm3) to give a clear solution,
which was stirred at room temperature for 4 h. The white solid
formed was filtered off, washed with cold water, and dried in vacuo.
Yield: 1046 mg, 93%. Anal. Found: C: 55.6, H: 6.5, N: 17.5, S:
13.4; C11H15N3OS (237.32 g/mol) requires C: 55.7, H: 6.4, N: 17.7,
S: 13.5%. IR(cm-1): ν(N-H) 3191, 3367; ν(CdN) 1608; ν(CdS)
1
836. H NMR (CDCl3): 8.58 (s, 1H, NNH), 7.63 (m, 2H, H2/H6,
Figure 12. Structure of 2 viewed along the ab plane.
N = 8,8), 7.62 (br, 1H, NHMe), 6.85 (m, 2H, H3/H5, N = 8,8), 3.85
(s, 3H, OMe), 3,27 (d, 3H, NHMe, JNHMe= 4.4), 2.24 (s, 3H,
3
as for compounds 6-10. In the former case, the signal that
appears at higher field is assigned to the noncoordinated
phosphorus nucleus at -25.02, 3, -9.54, 4, -10.40, 5, ppm,
however, in compounds 6-10 this signal is displaced to lower
field ca. 40 ppm in 6-8, and it is less strongly shifted in the
mixed palladium/platinum compounds 9, 23 ppm, and 10,
20 ppm, reflecting coordination of the free phosphorus atom
to the second metal center; this is even more evident for the
platinum complexes 9 and 10 which show satellites by
coupling of the shifted phosphorus to the 195Pt nucleus.
MeCdN). Single crystals of 1 were grown by slow evaporation from
ethanol solution.
[Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}]4 (2). To a stirred
solution of potassium tetrachloropalladate (200 mg, 0.61 mmol)
in water (6 cm3) was added ethanol (40 cm3). The fine yellow
suspension of potassiun tetrachloropalladate obtained was treated
with ligand 1 (1.1 equiv, 160 mg, 0.67 mmol). The mixture was
stirred for 24 h at room temperature. The yellow precipitate was
filtered off, washed with ethanol, and dried.
Yield: 185 mg, 89%. anal. found: C: 38.6, H: 3.9, N: 12.0, S: 9.2;
C44H52N12O4S4Pd4 (1366.90 g/mol) requires C: 38.7, H: 3.8, N: 12.3, S:
1
9.4%. IR(cm-1): ν(N-H) 3358; ν(CdN) 1573. H NMR (CDCl3):
7.13 (d, 1H, H5, 4J(H3H5) = 2.7), 6.50 (d, 1H, H2, 3J(H2H3) = 8.6),
6.40 (dd, 1H, H3, J(H2H3) = 8.6, J(H3H5) = 2.7), 4.99 (q, 1H,
Conclusions
3
4
3
The synthesis and structural study of bimetallic systems of
the type [MCl2{Pd[4-MeOC6H3C(Me)dNNdC(S)NHMe]-
(Ph2PRPPh2)-P,S}] [where R = CH2, (CH2)2, C = CH2 and
M = Pd, Pt] enabled the identification of new homo- and
heterobimetallics from palladacycle thiosemicarbazone-P,S-
metaloligands with diphosphines other than Ph2PCH2PPh2.
The presence of short contacts involving hydrogen bonding
NHMe, JNHMe= 5.1), 3.87 (s, 3H, OMe), 2.98 (d, 3H, NHMe,
3JNHMe = 5.1), 1.84 (s, 3H, MeCdN). FAB-MS: m/z 1366 [M]þ.
Single crystals of 2 were grown by slow evaporation from a dichloro-
methane/hexane (3:1) solution.
[Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}(Ph2PCH2PPh2-P)]
(3). The diphosphine Ph2PCH2PPh2 (112.5 mg, 0.29 mmol) was
added to a solution of complex 2 (100 mg, 0.07 mmol) in acetone
(20 cm3). The mixture was stirred for 24 h. The resulting yellow solid
was filtered off and dried.
and C-H π interactions determines the structural motifs
3 3 3
Yield: 149.1 mg, 70%. Anal. Found: C: 59.9, H: 5.0, N: 5.9, S: 4.5;
36H35N3OP2SPd (726.12 g/mol) requires C: 59.6, H: 4.9, N: 5.8, S:
present in the crystal structures, where antiparallel chains of
molecules arranged in sheets are stacked together face-to-face
or in a zigzag fashion. The latter is mainly determined by
the presence of solvent molecules that give different environ-
ments in the compounds with Ph2PCH2PPh2 and Ph2PC-
(dCH2)PPh2. The intermolecular interactions also allow
visualization of the remarkable disposition displayed by the
tetranuclear palladacycle.
C
4.4%. IR(cm-1): ν(N-H) 3357; ν(CdN) 1577. 1H NMR (CDCl3):
3
8.0-7.1 (m, 20H, 4ꢀPh), 6.92 (d, 1H, H2, J(H2H3) = 8.2), 6.30
(dd, 1H, H3, 3J(H2H3) = 8.2, 4J(H3H5) = 2.7), 5.85 (m, 1H, H5),
4.70 (q, 1H, NHMe, 3JNHMe= 4.9), 3,26 (d, 2H, PCH2P, 2J(HP) =
8.9), 3.14 (s, 3H, OMe), 2.97 (d, 3H, NHMe, 3JNHMe= 4.9), 2.32 (s,
3H, MeCdN). 31P-{1H} NMR (CDCl3): 26.60 (d, PA, 2JAB = 72.0),
-25.02 (d, PB, 2JAB = 72.0).
Compounds 4 and 5 were obtained similarly as yellow solids from
the diphosphines Ph2PC(CH2)2PPh2 and Ph2PC(dCH2)PPh2, re-
spectively.
Experimental Procedures
[Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}(Ph2PC(CH2)2PPh2-
P)] (4). Yield: 192.3 mg, 87%. Anal. Found: C: 60.9, H: 5.1, N: 5.6, S:
4.2; C38H37N3OP2SPd (752.15 g/mol) requires C: 60.7, H: 5.0, N: 5.6,
S: 4.3%. IR(cm-1): ν(N-H) 3434; ν(CdN) 1577. 1H NMR (CDCl3):
8.0-7.2 (m, 4ꢀPh), 7.04 (d, 1H, H2, 3J(H2H3) = 8.2), 6.53 (dd, 1H,
H5, 3J(H5P) = 4.5, 4J(H3H5) = 2.3), 6.45 (dd, 1H, H3, 3J(H2H3) =
General Comments. Solvents were purified by standard meth-
ods.41 4-Methoxiacetophenone, 4-methyl-3-thiosemicarbazide,
potassium tetrachloropalladate, palladium chloride, and platinum
chloride (all from Aldrich) were used as supplied; bis(benzo-
nitrile)dichloropalladium and bis(benzonitrile)dichloroplatinum
were synthesized in our laboratory by refluxing palladium or
platinum chloride in benzonitrile. 1,1-Bis(diphenylphosphine)cyclo-
propane, Ph2PC(CH2)2PPh2, was synthesized using the Schmidbaur
method.42 Elemental analyses were performed with a Fisons elemental
analyzer, model 1108. IR espectra were recorded as Nujol mulls or
polythene discs on Perkin-Elmer 1330, Mattson model Cygnus-100,
and Bruker model IFS-66 V spectrophotometers. 1H NMR spectra in
solution were recorded in CDCl3 at room temperature on Varian
4
8.2, J(H3H5) = 2.3), 4.56 (br, 1H, NHMe), 3.51 (s, 3H, OMe),
2.89 (d, 3H, NHMe, 3JNHMe= 5.2), 2.32 (s, 3H, MeCdN). 31P-{1H}
NMR (CD2Cl2): 61.32 (d, PA, 2JAB = 28.0), -9.54 (d, PB, 2JAB
28.0).
=
[Pd{4-MeOC6H3C(Me)dNNdC(S)NHMe}(Ph2PCdCH2PPh2-
P)] (5). Yield: 176.7 mg, 82%. Anal. Found: C: 60.3, H: 5.0, N: 5.6, S:
4.3;C37H35N3OP2SPd(738.13 g/mol) requires C: 60.2, H: 4.8, N: 5.7,

Article
Crystal Growth & Design, Vol. 10, No. 2, 2010 707
S: 4.3%. IR(cm-1): ν(N-H) 3357; ν(CdN) 1579. 1H NMR (CDCl3):
3J(HPcis) = 17.6), 6.03 (q, 1H, NHMe, 3JNHMe = 4.7), 5,73 (m, 1H,
H5), 3.21 (s, 3H, OMe), 3.06 (d, 3H, NHMe, 3JNHMe = 4.7), 2.37 (s,
3H, MeCdN). 31P-{1H} NMR (CDCl3): 34.14 (d, PA, 2JAB = 66.1),
9.61 (d, PB, 2JAB = 66.1, 1J(PPt) = 3842). Single crystals of 10 were
grown by slow evaporation from a dichloromethane/hexane (3:1)
solution.
3
8.2-7.1 (m, 4xPh), (d, 1H, H2, J(H2H3) = 8.2), 7.0 (d, 1H, H2,
3J(H2H3) = 8.8), 6.71 (br, 1H, PC=CH), 6.38 (dd, 1H, H3, (dd, 1H,
H3, 3J(H2H3) = 8.8, 4J(H3H5) = 2.9), 6,00 (m, 1H, H5), 5.88 (br,
3
1H, PC=CH), 4.71 (q, 1H, NHMe, JNHMe= 4.9), 3.19 (s, 3H,
OMe), 2.99 (d, 3H, NHMe, 3JNHMe = 4.9), 2.39 (s, 3H, MeCdN).
31P-{1H} NMR (CDCl3): 46.23 (d, PA, 2JAB = 83.0), -10.40 (d, PB,
2JAB = 83.0).
X-ray Structure Determination. Single crystals of compounds 1, 2,
6, 7, 8 CH2Cl2, 9, and 10 CH2Cl2 were mounted on glass fibers for
3
3
[PdCl2{Pd[4-MeOC6H3C(Me)=NN=C(S)NHMe](Ph2PCH2-
PPh2)-P,S}] (6). To a solution of complex 3 (50 mg, 0.07 mmol) in
acetone (12 cm3) was added [PdCl2(NCPh)2] (26.4 mg, 0.07 mmol)
and the mixture was stirred for 24 h. The resulting orange solid
was filtered off and dried. Yield: 38.9 mg, 64%. Anal. Found: C:
47.9, H: 3.8, N: 4.6, S: 3.5; C36H35Cl2N3OP2SPd2 (903.44 g/mol)
requires C: 47.9, H: 3.9, N: 4.7, S: 3.6%. IR(cm-1): ν(N-H) 3417;
ν(CdN) 1577, ν(Pd-Cl) 305, 297. 1H NMR (CDCl3): 7.9-7.2 (m,
20H, 4ꢀPh), 7.20 (d, 1H, H2, 3J(H2H3) = 8.7), 6.49 (dd, 1H, H3,
3J(H2H3) = 8.7, 4J(H3H5) = 2.7), 5.92 (m, 1H, H5), 5.29 (q, 1H,
data collection in a Siemens Smart-CCD-100043 Bruker diffracto-
meter equipped with a graphite monochromator at 293 K using
Mo KR radiation (λ = 0.71073 A). Intensity data were collected as a
series of frames, each of ω width 0.3°, integrated44 and corrected for
absorption45 and solved and refined using routine techniques.46a
Crystallographic data and selected interatomic distances and angles
are listed in Tables 1-3. ORTEP46b and MERCURY47 drawings
are shown in Figures 1-11 and in the Supporting Information.
Acknowledgment. We thank the Spanish Ministerio de
ꢀ
3
NHMe, JNHMe = 5.2), 3,24 (t, 2H, PCH2P, N = 22.6), 3.23 (s,
3H, OMe), 3.10 (d, 3H, NHMe, JNHMe = 5.2), 2.50 (s, 3H,
Ciencia e Innovacion (Projects CTQ2006-15621-C01/BQU
3
and CTQ2006-15621-C02/BQU) for financial support, and
the Xunta de Galicia, Spain, for support under project
INCITE08ENA209044ES. L.A. and J.M.A. acknowledge
fellowships from the Xunta de Galicia (Spain).
2
MeCdN). 31P-{1H} NMR (CDCl3): 23.15 (d, PA, JAB = 30.2),
17.12 (d, PB, 2JAB = 30.2). Single crystals of 6 were grown by slow
evaporation from a dichloromethane/hexane (3:1) solution.
Compounds 7 and 8 were obtained as orange solids following a
similar procedure, from 4 and 5, respectively.
Supporting Information Available: Figures S1, S2, S3, S4, S5
containing crystal structures of 6, 8 CH2Cl2, 1, 2 viewed along the
[PdCl2{Pd[4-MeOC6H3C(Me)dNNdC(S)NHMe](Ph2PC(CH2)2-
PPh2)-P,S}] (7). Yield: 35.1 mg, 57%. Anal. Found: C: 49.0, H: 4.1, N:
4.6, S: 3.4; C38H37Cl2N3OP2SPd2 (929.48 g/mol) requires C: 49.1, H:
4.0, N: 4.5, S: 3.4%. IR(cm-1): ν(N-H) 3434; ν(CdN) 1574,
ν(Pd-Cl) 319, 293. 1H NMR (CDCl3): 8.0-7.2 (m, 20H, 4xPh),
3
a axis, and view of π-π and CH π interactions in 10, respectively;
3 3 3
Tables T1-T7. This material is available free of charge via the
Internet at http://pubs.acs.org. Also, crystallographic data for this
paper can be obtained at the Cambridge Crystallographic Data
Centre [CCDC numbers 728243, 728244, 728245, 728246, 728247,
728248, and 728249 for 1, 2, 6, 7, 8 CH2Cl2, 9 and 10 CH2Cl2,
3
3
7.12 (d, 1H, H2, J(H2H3) = 8.2), 6.38 (dd, 1H, H3, J(H2H3) =
8.2, 4J(H3H5) = 2.3), 5.58 (q, 1H, NHMe, 3JNHMe= 5.3), 5.43 (dd,
1H, H5, 3J(H5P) = 4.7, 4J(H3H5) = 2.3), 3.12 (d, 3H, NHMe,
3JNHMe= 5.3), 2.94 (s, 3H, OMe), 2.46 (s, 3H, MeCdN), 1.3-1.0 (m,
4H, PC(CH2)2). 31P-{1H} NMR (CDCl3): 46.52 (d, PA, 2JAB = 65.2),
3
3
respectively].
2
References
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3
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3
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=
5.2), 3.20 (s, 3H, OMe), 3.10 (d, 3H, NHMe, 3JNHMe= 5.2), 2.48 (s,
3H, MeCdN). 31P-{1H} NMR (CDCl3): 36.41 (d, PA, 2JAB = 73.8),
27.82 (d, PB, JAB = 73.8). Single crystals of 8 were grown by slow
2
evaporation from a dichloromethane/hexane (3:1) solution.
Compounds 9 and 10 were obtained analogously as yellow solids
from 3 and 5, respectively, and [PtCl2(NCPh)2].
[PtCl2{Pd[4-MeOC6H3C(Me)=NN=C(S)NHMe](Ph2PCH2-
PPh2)-P,S}] (9). Yield: 38.6 mg, 57%. Anal. Found: C: 43.6, H:
3.5, N: 4.0, S: 3.1; C36H35Cl2N3OP2SPdPt (992.10 g/mol) requires
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1576, ν(Pd-Cl) 314, 292. 1H NMR (CDCl3): 8.0-7.2 (m, 20H,
4ꢀPh), 7.17 (d, 1H, H2, 3J(H2H3) = 8.6), 6.44 (dd, 1H, H3,
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´
3
NHMe, JNHMe= 5.2), 3,25 (t, 2H, PCH2P, N = 22.0), 3.20 (s,
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3
2
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1
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[PtCl2{Pd[4-MeOC6H3C(Me)dNNdC(S)NHMe](Ph2PCdCH2-
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