Synthesis characterisation and study of the first luminescent platinum(II) compound with a [C,N,S]- terdentate ligand. X-ray crystal structure of

Article abstract of DOI:10.1016/S0022-328X(03)00011-1

The study of the reactions of the thioimine C₆H₅-CH=N-(C₆H₄-2-SMe) with cis-[PtCl₂(DMSO)₂] or cis-[PtCl₂(PhCN)₂] is reported. The results obtained from the reactions of cis- [PtCl₂(DMSO)₂] with the Schiff base suggest that this platinum(II) complex induces the hydrolyses of the imine. In contrast to these findings, the treatment of equimolar amounts of C₆H₅-CH=N- (C₆H₄-2-SMe) and cis-[PtCl₂ (PhCN)₂] under refluxing toluene lead to the cycloplatinated complex: [Pt{C₆H₄-CH=N- (C₆H₄-2-SMe)}Cl], which is luminescent in solution at 298 K. The X-ray crystal structure of this compound reveals that the ligand acts as a [C(sp²),N,S]^- ligand and has the E (anti-) conformation. The reaction of the cycloplatinated compound [Pt{C₆H₄-CH=N-(C₆H₄-2-SMe)} Cl] with PPh₃ is also reported. This process produces the cleavage of the Pt-S bond and the formation of [Pt{C₆H₄-CH=N-(C₆H₄-2-SMe)}Cl (PPh₃)] in which the ligand acts as a monoanionic (C,N)^- bidentate group.

Full text of DOI:10.1016/S0022-328X(03)00011-1

Journal of Organometallic Chemistry 669 (2003) 164ꢂ171
/
www.elsevier.com/locate/jorganchem
Synthesis, characterisation and study of the first luminescent
platinum(II) compound with a [C,N,S]ꢀ terdentate ligand.
X-ray crystal structure of [Pt{C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ
/
2-SMe)}Cl]
Amparo Caubet a, Concepcio´n Lo´pez a,*, Xavier Solans b, Merce` Font-Bard´ıa b
a Departament de Quimica Inorga`nica, Facultat de Qu´ımica, Universitat de Barcelona, Mart´ı i Franque`s 1-11, E-08028 Barcelona, Spain
b Departament de Cristal.lografia, Mineralogia i Dipo`sits Minerals, Facultat de Geologia, Universitat de Barcelona, Mart´ı i Franque`s s/n, E-08028
Barcelona, Spain
Received 15 November 2002; received in revised form 6 January 2003; accepted 6 January 2003
Abstract
The study of the reactions of the thioimine C6H5ꢀ
reported. The results obtained from the reactions of cis-[PtCl2(DMSO)2] with the Schiff base suggest that this platinum(II) complex
induces the hydrolyses of the imine. In contrast to these findings, the treatment of equimolar amounts of C6H5ꢀCHꢁNꢀ(C6H4ꢀ2-
SMe) and cis-[PtCl2(PhCN)2] under refluxing toluene lead to the cycloplatinated complex: [Pt{C6H4ꢀCHꢁNꢀ(C6H4ꢀ2-SMe)}Cl],
which is luminescent in solution at 298 K. The X-ray crystal structure of this compound reveals that the ligand acts as a
[C(sp2),N,S]ꢀ ligand and has the E (anti-) conformation. The reaction of the cycloplatinated compound [Pt{C6H4ꢀ
CHꢁNꢀ(C6H4ꢀ
2-SMe)}Cl] with PPh3 is also reported. This process produces the cleavage of the PtꢀS bond and the formation of [Pt{C6H4ꢀCHꢁ
Nꢀ(C6H4ꢀ
2-SMe)}Cl(PPh3)] in which the ligand acts as a monoanionic (C,N)ꢀ bidentate group.
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ/2-SMe) with cis-[PtCl2(DMSO)2] or cis-[PtCl2(PhCN)2] is
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
# 2003 Elsevier Science B.V. All rights reserved.
Keywords: Platinum(II); Cycloplatination; Luminiscence
1. Introduction
important from the point of view of their luminescent
properties [4].
Platinum(II) compounds of the type [Pt(L)Cl] where
L stands for a monoanionic (C,N,X)ꢀ (Xꢁ
N, P, O or
S) terdentate group have attracted considerable interest
On the other hand, despite the wide variety of
platinacycles having ‘Pt(C,N,X)Cl’ cores described so
far and the potential interest of the presence of three
donor atoms (C, N and X) of different hardness [5]
bound to the central atom, the number of platinum(II)
/
in recent years due to their applications in several areas
[1ꢂ4]. In addition to the potential antitumoral activity
/
of the platinum(II) compounds having (C,N,X)ꢀ li-
gands [2], this sort of complexes have an additional
interest as precursors for the synthesis of organic or
organometallic compounds [3]. For instance Johnson
and Sames have recently reported the total synthesis of
the antitumour agent Rhazinilam based on the use of a
platinum(II) complex having a (C,N,N?)ꢀ terdentate
group [3a]. Besides that, platinum(II) compounds with
(N,N), (C,N)ꢀ or (C,N,N?)ꢀ ligands are particularly
compounds having Xꢁ
most of the examples reported so far arise from the
H] bond of azobenzene
/
sulphur are scarce [6,7] and
activation of the s[C(sp2)ꢀ
/
derivatives holding thioether groups [6].
As a part of a project focused on the synthesis and the
study of the potential utilities of platinum(II) complexes
having (N,S) or (C,N,S)ꢀ ligands, a few years ago we
centred our research in the study of the reactivity of
imines Rꢀ
/
C(H)ꢁ
/
NꢀR? (where the R? contains a
/
thioether group as a pendant arm) towards platinum(II)
[7]. Recent studies have shown that the reaction of
* Corresponding author. Tel.: ꢃ
7725.
E-mail address: conchi.lopez@qi.ub.es (C. Lo´pez).
/
34-93-402-1274; fax: ꢃ34-93-490-
/
C6H5ꢀ
/
C(H)ꢁ
/
Nꢀ
/
(CH2ꢀ
/
CH2ꢀ
/
SEt) (1a) (Plate 1) with
CHꢁNꢀ(CH2ꢀ
cis-[PtCl2(DMSO)2] leads to [Pt{C6H4ꢀ
/
/
/
/
0022-328X/03/$ - see front matter # 2003 Elsevier Science B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00011-1

A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ
/171
165
In view of this, we decided to elucidate whether the
use of a different platinum(II) derivative as starting
material, such as cis-[PtCl2(PhCN)2] and the use of non-
protic solvents could prevent the hydrolysis of the
ligand, and allow the stabilisation of the platinum(II)
imine derivatives.
The treatment of 1b with the stoichiometric amount
of cis-[PtCl2(PhCN)2] in refluxing toluene produced two
different platinum(II) complexes (Scheme 1).
Plate 1.
The characterisation data of the less soluble and
minor component agreed with those obtained for cis-
CH2ꢀ
/
SEt)}Cl] (2a) [7a]. In the view of these facts, we
decided to elucidate whether: the replacement of the
‘ꢀCH2ꢀCH2ꢀ’ moiety in 1a by a less flexible moiety
such as a 1,2-disubstituted phenyl ring in C6H5ꢀC(H)ꢁ
Nꢀ(C6H4-2SEt) (1b) (Plate 1), could be important in
[PtCl2(H2Nꢀ
mental analyses of the second compound were consis-
tent with those expected for: [Pt{C6H4ꢀCHꢁNꢀ(C6H4ꢀ
2-SMe)}Cl] (2b). The 195Pt{1H}-NMR spectrum of
complex 2b showed a singlet at ca. ꢀ3708 ppm. The
position of this signal is similar to those reported for
[Pt{C6H4ꢀCHꢁNꢀ(CH2ꢀCH2ꢀSEt)}Cl] (2a) [dꢁ
3716 ppm] [7a] and [Pt{C6H4ꢀCHꢁNꢀCH(CO2Me)ꢀ
/
C6H4ꢀ/2-SMe)] (see above), while the ele-
/
/
/
/
/
/
/
/
/
/
determining the mode of binding of this ligand to the
platinum(II) or the co-planarity of all the rings around
the metal which is of outstanding relevance in the view
of their potential applications.
/
/
/
/
/
/
/
ꢀ
/
/
/
/
/
CH2ꢀ
/
CH2ꢀ
/
SMe)}Cl] [dꢁ
/
ꢀ3832 ppm] [7b], in which
/
the ligands also act as a [C(sp2),N,S]ꢀ terdentate group.
All these findings suggested that the formation of 2b
2. Results and discussion
involved the activation of the s[C(sp2)ꢀ
/
H) bond, to
produce a five-membered ring platinacycle. The X-ray
crystal structure of this complex confirmed these results.
The molecular structure of 2b together with the atom
labelling scheme is depicted in Fig. 1. Bond lengths and
a selection of bond angles are presented in Table 1. The
In a first attempt to achieve the cycloplatination of
ligand 1b, we decided to use the procedure described
recently for the synthesis of [Pt{C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(CH2ꢀ
/
CH2ꢀSEt)}Cl] (2a) [7a]. This method consists of the
/
reaction of equimolar amounts of 1a and cis-
[PtCl2(DMSO)2] in refluxing methanol. However,
structure consists of discrete molecules of [Pt{C6H4ꢀ
/
CHꢁNꢀ(C6H4ꢀ2-SMe)}Cl] separated by van der Waals
/
/
/
when the reaction was carried out using C6H5ꢀ
/
CHꢁ
/
contacts. In each of these molecules the platinum(II) is
in a slightly distorted square-planar environment [11]
bound to the chlorine, the sulphur, the imine nitrogen
and the C(1) atom of the phenyl ring. This confirmed the
conclusions reached by NMR studies which suggested a
[C(sp2),N,S]ꢀ mode of binding of the ligand.
Nꢀ(C6H4ꢀ2-SMe) (1b) under identical experimental
/
/
conditions as described for 1a, two different compounds
could be isolated in the two cases. One of them was
identified, on the basis of infrared and NMR spectro-
scopy, as benzaldehyde; while the characterisation data
of the second component agreed with those expected for
Each molecule contains a [6,5,5,6] tetracyclic system
cis-[PtCl2(H2Nꢀ
/
C6H4ꢀ
/
2-SMe)] [8] probably resulting
formed by an aryl ring which shares the C(8)ꢀ
/
C(13)
from the hydrolysis of the ligand. These findings are in
sharp contrast with those obtained for the closely
bond with the chelate formed by the coordination of the
two heteroatoms (N and S) to the platinum(II), a five-
membered metallacycle and the other phenyl ring. The
related substrate: C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(CH2ꢀ
/
CH2ꢀ
/
SEt) (1a)
[7a], for which no evidences of the hydrolysis of the
ligand were detected in the course of the reaction by
NMR spectroscopy. Furthermore, since it has been
demonstrated that ligand 1b does not degrade in the
presence of stoichiometric amounts of Na2[PdCl4] in
methanol (at room temperature or under refluxing
conditions) or even in the presence of a base [9], we
propose that in the reaction under study, the hydrolyses
of the ligand may be promoted by the platinum(II)
reagent. Recent studies focused on the reaction of
diimines derived from (1R,2R)-1,2-diaminocyclohexane
(L?) with cis-[PtCl2(DMSO)2] in refluxing 2-methox-
yethanol have also lead to the formation of cis-
[PtCl2(L?)], and these results have been rationalised
using a similar argument [10].
Ptꢀ
/
C and Ptꢀ/N bond distances are consistent with
those reported for a wide variety of platinacycles having
(C,N)ꢀ, (C,N,N?)ꢀ or (N,C,N?)ꢀ ligands [12], but the
Ptꢀ
/
S bond length in 2b is clearly greater than the value
S(thioether) derivatives
(ca. 2.25 A) [13]. However, the platinumꢂligand bond
usually found for platinum(II)ꢂ
/
˚
/
distances of 2b do not differ significantly from those
reported for 2a [7a].
The angles between adjacent atoms in the coordina-
tion sphere lie in the range: 81.8(2)ꢂ96.7(2)8. The
/
smallest values corresponding to the terdentate ligand.
The metallacycle, which is formed by the atoms: C(1),
C(6), C(7), N and Pt, is nearly planar [14], contains the
ꢂCꢁ
/
Nꢀ
/
functional group (endocyclic) and forms
angles of 5.22, 4.54 and 3.138 with the attached aryl

166
A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ171
/
Scheme 1. (i) Cis-[PtCl2(PhCN)2], in refluxing toluene (3b). In this case compound cis-[PtCl2(H2Nꢀ
/
C6H4ꢀ2SMe)] was also formed as a by product
/
(see text). (ii) PPh3 in CH2Cl2 in a Pt:PPh3 molar ratioꢁ1.
/
The five-membered chelate ring formed by the
platinum and the ‘ꢀNꢀ(C6H4ꢀ2-SMe)’ fragment is
nearly planar [15] and it forms an angle of ca. 2.738
with the phenyl ring attached to it. In this complex the
two phenyl rings are planar and their main planes form
an angle of 5.568.
The separation between the Cl and the H(2) atom is
˚
(2.914 A) slightly shorter than the sum of the van der
˚
Waals radii (Cl, 1.75 and H, 1.20 A) [16] of these atoms,
Table 1
Bond lengths (in A) and selected bond angles (in 8) for [Pt{C6H4ꢀ
Nꢀ(C6H4ꢀ2-SMe)}Cl] (2b)
˚
/
/
/
/
CHꢁ
/
/
/
Bond lengths
Ptꢀ
Ptꢀ
Sꢀ
Nꢀ
C(1)ꢀ
C(2)ꢀ
C(4)ꢀ
C(6)ꢀ
C(8)ꢀ
C(10)ꢀ
C(12)ꢀ
/
N
1.928(6)
2.292(2)
1.777(7)
1.303(8)
1.379(9)
1.410(12)
1.370(11)
1.461(9)
1.412(10)
1.377(14)
1.394(10)
Ptꢀ
Ptꢀ
Sꢀ
Nꢀ
C(1)ꢀ
C(3)ꢀ
C(5)ꢀ
C(8)ꢀ
C(9)ꢀ
C(11)ꢀ
/
C(1)
2.016(6)
/Cl
/S
2.349(2)
1.830(9)
1.451(8)
1.390(9)
/
C(13)
/
C(14)
/C(7)
/C(8)
/
C(2)
C(3)
C(5)
C(7)
C(13)
/
C(6)
C(4)
C(6)
C(9)
C(10)
/
/
1.364(14)
1.416(10)
1.391(11)
1.369(12)
1.378(14)
thus suggesting a Clꢀ ꢀ ꢀH(2)ꢀ ꢀ ꢀC(2) intramolecular inter-
action. This type of interactions has also been described
for a wide variety of cyclopalladated and cycloplati-
nated complexes containing (C,N)ꢀ or (C,N,N?)ꢀ
ligands and a chloride bound to the metal atom [17].
The crystal structure also confirms that 2b consists on
a 1:1 mixture of enantiomers. This is consistent with the
lack of chiral induction during the cyclometallation
process.
Several authors have suggested that for cycloplati-
nated complexes having (C,N,N?)ꢀ terdentate groups,
the planarity of the terdentate group, the p-stacking of
the aryl rings of the ligand and the Ptꢀ ꢀ ꢀPt separation,
are particularly important in the view of the potential
photo-luminescent properties of this sort of compounds
/
/
/
/
/
/
/C(11)
/C(12)
/C(13)
Selected bond angles
NꢀPtꢀC(1)
ClꢀPtꢀ
PtꢀC(1)ꢀ
NꢀC(7)ꢀC(6)
PtꢀNꢀC(8)
C(8)ꢀC(13)ꢀ
C(13)ꢀSꢀPt
/
/
81.8(2)
95.69(8)
111.4(5)
115.2(6)
120.2(4)
119.8(5)
104.3(3)
Nꢀ
C(1)ꢀ
C(1)ꢀ
C(7)ꢀ
NꢀC(8)ꢀ
C(14)ꢀSꢀ
C(2)ꢀC(1)ꢀ
/
Ptꢀ
Ptꢀ
C(6)ꢀ
NꢀPt
C(13)
C(13)
Pt
/
S
85.93(15)
96.7(2)
/
/S
/
/
Cl
/
/
C(6)
/
/C(7)
115.4(6)
115.9(4)
117.5(6)
101.1(4)
131.1(6)
/
/
/
/
/
/
/
/
/
/S
/
/
/
/
/
/
group, the five-membered chelate ring and the other
phenyl ring, respectively.
[18ꢂ20]. In complex 2b, the atoms forming the tricyclic
/
Fig. 1. View of the crystal structure of compound [Pt{C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ2-SMe)}Cl] (2b) together with the atom labelling scheme.
/

A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ
/171
167
system mentioned above are nearly coplanar [21], and in
the unit cell the molecules are associated in pairs in a
head to tail arrangement where the shortest interplanar
co-ordination of the PPh3 ligand but also the cleavage of
the PtꢀS bond.
The 195Pt{1H}-NMR spectrum of 3b showed a doub-
let [1J(Ptꢀ
P)ꢁ3858 Hz] centred at dꢁ 4461 ppm.
The position of this signal is consistent with that
reported for [Pt{C6H4ꢀCHꢁNꢀ(CH2ꢀCH2ꢀSEt)}Cl-
P)ꢁ3806 Hz]
/
separation between the (C,N,S)ꢀ ligands is 3.91 A,
˚
/
/
/
ꢀ
/
which falls in the upper range expected for p-stacking
systems [22]. The long intermolecular Sꢀ ꢀ ꢀS distance
precludes the existence of any direct interaction between
these atoms. Besides that, the shortest Ptꢀ ꢀ ꢀPt distance
/
/
/
/
/
(PPh3)] (3a) [dꢁ
/
ꢀ
/
4485 ppm, 1J(Ptꢀ
/
/
[7a], in which the ligand also acts as a [C(sp2),N,S]ꢀ
terdentate group.
˚
between neighbouring molecules is [4.216(3) A] clearly
larger than the values reported for related platinacycles
holding [C(sp2),N,N?]ꢀ and [C(sp2),N,S]ꢀ terdentate
ligands for which intramolecular Ptꢀ ꢀ ꢀPt interactions
As mentioned above, cycloplatinated compounds
having terdentate {[C,N,N?]ꢀ or [N,C,N?]ꢀ} ligands
are also interesting from the point of view of their
photophysical properties and in particular due to their
potential luminescence, which may allow the design of
new devices or materials [4,19b,19c,19d,26]. On this
basis, we decided to study whether compound 2b, which
has a (C,N,S)ꢀ ligand could also exhibit luminescence.
have been proposed [18ꢂ20].
/
In order to elucidate whether the flexibility of the
moiety which links the two heteroatoms in the cyclo-
platinated complexes 2a and 2b could be important in
determining the lability of the Ptꢀ
decided to study the reaction of 2b with PPh3 and to
compare the results with those reported for [Pt{C6H4ꢀ
CHꢁNꢀ(CH2ꢀCH2ꢀ2-SMe)}Cl] (2a).
/
S or Ptꢀ/Cl bond, we
The UVꢂ
/
vis spectrum of 2b in CH2Cl2 showed two
370 nm
/
intense bands (see Section 4) in the range 340ꢂ
/
/
/
/
/
(also observed in the spectrum of the free ligand)
assigned to intraligand transitions. At lower energies
When the stoichiometric amount of PPh3 was added
to a solution of 2b in CH2Cl2 at room temperature a
yellowish solution was formed. The subsequent concen-
tration of the solution followed by the addition of n-
hexane produced the precipitation of a yellow solid. Its
elemental analyses (see Section 4.1.2) were consistent
three less intense bands (in the range 400ꢂ500 nm, with
/
extinction coefficients, o, greater than 1000 were also
observed. As can be easily seen in Fig. 2, compound 2b
exhibits emission (lmax
ꢁ666 nm in CH2Cl2 at 298 K
/
(lexc 469 nm) and the excitation spectrum (also shown
ꢁ
/
with those expected for [Pt{C6H4ꢀ
SMe)}Cl(PPh3)] (3b) (Scheme 1). Its 31P{1H}-NMR
spectrum showed a signal at dꢁ19.34 ppm strongly
coupled with the 195Pt nucleus {1J(Pꢀ
Pt)ꢁ3858 Hz}.
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ
/
2-
in Fig. 2), closely matched the corresponding absorption
spectrum, even the shoulder at ca. 491 nm was observed.
In the view of these results and in order to elucidate
whether the luminescence of 2b could be induced by the
presence of the 1,2-disubstituted phenyl ring which
connects the two heteroatoms (N and S), we decided
/
/
/
Its position and multiplicity as well as the value of the
coupling constant suggested the presence of one PPh3
ligand bound to the platinum in a trans- arrangement to
the imine nitrogen. This is the usual result of the
reaction between (C,N)ꢀ cyclometallated compounds
and phosphine ligands [17,23,24] due to the so-called
transphobia effect [25]. 13C-NMR spectroscopic data are
presented in the Section 4 and the most relevant feature
observed in the 13C{1H}-NMR spectrum is the lowfield
shift of the signal due to the metallated carbon, when
compared with the free ligand [9]. In the 1H-NMR
spectrum of 3b, the signal due to the imine proton
to carry out a ‘parallel’ study using complex [Pt{C6H4ꢀ
CHꢁNꢀ(CH2ꢀCH2ꢀSEt)}Cl] (2a) in which the aryl ring
has been replaced by a ‘ꢀCH2ꢀCH2ꢀ’ fragment.
The UVꢂvis spectrum of 2a (Fig. 3(A)) showed four
bands in the range 300ꢂ400 nm. For the bands at higher
energies, the positions of their maxima [lꢁ314 and 328
nm] were very similar to those of the free ligand [lꢁ308
/
/
/
/
/
/
/
/
/
/
/
/
appeared as a doublet at dꢁ
coupling [4J(Hꢀ
P)ꢁ9.0 Hz] and also coupled with the
195Pt nucleus [3J(Hꢀ
Pt)ꢁ63 Hz], thus indicating the
/
10.68 ppm due to 31P
/
/
/
/
binding of the imine nitrogen to the platinum. However,
the signal due to the methyl protons of the SMe group
appeared as a singlet without 195Pt satellites. This
finding suggests that the reaction of 2b with PPh3
involved the cleavage of the Ptꢀ
[Pt{C6H4ꢀCHꢁNꢀ(C6H4ꢀ2-SMe)}Cl(PPh3)] (3b). This
result is similar to that reported for [Pt{C6H4ꢀCHꢁNꢀ
(CH2ꢀCH2ꢀSEt)}Cl] (2a), for which the addition of
PPh3 gave CHꢁNꢀ(CH2ꢀCH2ꢀSEt)}-
[Pt{C6H4ꢀ
/
SMe bond producing
/
/
/
/
/
/
/
/
/
/
/
/
/
/
Cl(PPh3)] (3a) under identical experimental conditions.
Thus, the formation of 3a and 3b required not only the
Fig. 2. Excitation and emission spectra of compound 2b in CH2Cl2 at
298 K with excitation at 466 nm and emission monitored at 666 nm.

168
A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ171
/
Fig. 3. (A) Absorption spectrum of compound [Pt{C6H4ꢀ
coefficients, o , (in dm3 molꢀ1 cm2) in parenthesis: 314 (3520); 328 (4188); 343 (3211) and 388 (3435)]. (B) Emission spectrum {lexcitation
lemission (max)ꢁ578 nm} of 2b in CH2Cl2 at 298 K.
/
CHꢁ
/
Nꢀ
/
(CH2ꢀ
/
CH2ꢀ
/
SEt)}Cl] (2b) [absorption wavelengths, lmax (in nm) and extinction
ꢁ
/
388 nm and
/
and 325 nm]. Consequently, these absorptions can be
attributed to intraligand transitions.
Besides that, as far as we know the new compound 2b
and complex 2a (which was reported previously [7a]) are
the first examples of a cycloplatinated complexes con-
taining a (C,N,S)ꢀ terdentate group, which exhibit
luminescence in CH2Cl2 at 298 K. Consequently, the
results presented here provide the first step of a new field
of research focused on the study of the photo-physical
properties and potential applications of platinacycles
similar to 2a or 2b formed by either the replacement of
the terminal chloride ligand (by an unsaturated groups
The position of the third band [lꢁ
nearly coincident with one of the bands observed in the
UVꢂvis spectrum of 2b [lꢁ 346 nm]; while the remain-
ing absorption band appeared at [lꢁ 388 nm] higher
energies than for 2a. Excitation at this wavelength
[lexc 388 nm] gave the emission spectrum depicted in
Fig. 3(B), showing a maxima [lmax 578 nm] at lower
wavelengths than complex 2a [lmax 666 nm]. This
finding indicates that the replacement of a ‘ꢀCH2ꢀ
CH2ꢀ’ unit between the two heteroatoms in 2a by the
/343 nm] was
/
/
/
ꢁ
/
ꢁ
/
ꢁ
/
/
/
such as: ꢀ
/
Cꢀ
/
Cꢀ
/
R moieties) or by the incorporation of
/
substituents in the backbone of the terdentate (C,N,S)ꢀ
ligand. Further work on this field is currently under
study.
1,2-disubstituted phenyl ring (in 2b) produces a red shift
of the position of the maximum observed in the emission
spectrum of compounds 2.
4. Experimental section
3. Conclusions
4.1. General comments
The results presented in this work have allowed us to
isolate and characterise two cycloplatinated complexes
in which ligand 1b acts as a monoanionic [C(sp2),N]ꢀ
bidentate ligand (in 3b) or as a terdentate [C(sp2),N,S]ꢀ
(in 2b). Besides that, the comparison of the results
reported here and those obtained for ligand 1a, indicate
that tiny changes in the moiety bridging the two
The ligand C6H5ꢀ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ
/
2-SMe) (1b) and
SEt)}Cl] (2a)
complex [Pt{C6H4ꢀCHꢁ
/
/
Nꢀ
/
(CH2ꢀ
/
CH2ꢀ
/
were prepared as described previously [7a,12].The pla-
tinum(II) derivatives: cis-[PtCl2(PhCN)2] and K2[PtCl4]
were purchased from Aldrich and used as received and
cis-[PtCl2(Me2SO)2] was prepared as described pre-
viously [27]. All the solvents used in this study were
dried and distilled before use, except MeOH which was
of HPLC grade. Elemental analyses (C, H, N and S)
were carried out at the Institut de Qu´ımica Bio-Organica
(C.S.I.C., Barcelona). FABMS of compounds 2b and 3b
were obtained with a VG-Quatro, Fission Instrument
using 3-nitrobenzylaalcohol (NBA) as matrix. Infrared
spectra were obtained with a NICOLET-Impact 400
instrument. Routine 1H- and 13C{1H}-NMR spectra
were recorded with either a Gemini-200 MHz or a
Bruker-DXR-250 instrument using CDCl3 as solvent
and SiMe4 as internal standard, except where quoted.
High resolution mono-dimensional 1H-NMR experi-
ments as well as the 2D-heteronuclear (HMBC and
HSQC) experiments were obtained with either a Bruker
heteroatoms (a ‘ꢀ
/
CH2ꢀ
/
CH2ꢀ/’ unit in 1a or a 1,2-
disubstituted phenyl ring in 1b) are important to modify
the stability of these ligands to undergo a hydrolyses
process in the presence of cis-[PtCl2(DMSO)2]. In
contrast with these findings, the synthesis of a cyclopla-
tinated complex derived from imine 1b could be
successfully achieved when cis-[PtCl2(PhCN)2] was
used as starting material. The cycloplatinated complexes
2a and 2b exhibit similar reactivity versus PPh3, thus
suggesting that the replacement of the ‘ꢀ
/
CH2ꢀ
/
CH2ꢀ
/’
fragment (in 2a) by a more rigid 1,2-disubstituted phenyl
ring (in 2b) does not introduce significant variation in
this sort of process which involves the cleavage of the
Ptꢀ/S bond.

A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ
/171
169
Avance-500DMX or a Varian-VXR500 instrument
using the same solvents and references as mentioned
above. The 195Pt{1H}-NMR spectra of 3a and 3b were
obtained with a Bruker-DXR-250 instrument and the
chemical shifts given are referred to a H2[PtCl6] solution
in D2O as external reference. The 31P{1H}-NMR
spectrum of 3b was obtained with a Bruker -DXR-250
instrument using CDCl3 as solvent and P(OMe)3 as
20 8C) for ca. 10 min. The resulting yellow solution
was concentrated to ca. 2 ml on a rotary evaporator,
and then treated with n-hexane. The yellow solid formed
was filtered out, washed with n-hexane, air-dried and
then dried in vacuum for 24 h (yield: 79 mg, 83%).
Characterisation data: Anal. Calc. for: C32H27NClPPtS×
0.5CH2Cl2 (Found): C, 51.25 (51.35); H, 3.78 (3.85), N,
1.84 (2.00) and S, 4.21 (4.43)%. MS (FABꢃ): m/zꢁ
652
{Mꢀ(Cl)ꢀ IR: n(ꢂCꢁNꢀ)ꢁ1590
(0.5CH2Cl2)}ꢃ.
cmꢀ1. H-NMR data (500 MHz): 10.68 [d, 1H, ꢀ
CHꢁ
SMe],
7.3], 6.67 [t, 1H, H4, 3J(Hꢀ
/
/
reference [d31P{P(OMe)3}ꢁ
/140.17 ppm]. In all cases
/
/
/
/
/
1
the chemical shifts (d) are given in ppm and the coupling
constants (J) in Hz. The assignments of the signals
/
/
3
3
Nꢀ
6.40 [d, 1H, H3, 3J(Hꢀ
H)ꢁ
7.2], 7.13 [t, 1H, H5, J(Hꢀ
/
, J(Hꢀ
/
Pt)ꢁ
/
63, J(Hꢀ
/
Pt)ꢁ
/
9], 2.13 [s, 3H, ꢀ
/
1
detected in the H- and 13C-NMR spectra were carried
/
H)ꢁ
/
/
3
out with the aid of two-dimensional NMR experiments.
vis spectra of 2a and 2b in CH2Cl2 were
/
/
H)ꢁ7.3], 8.18 [d, 1H,
/
3
3
The UVꢂ
/
H3?, J(Hꢀ
5.12 [s, 1H, CH2Cl2] and 6.40ꢂ
and aromatic protons of the PPh3 ligand). 13C{1H}-
NMR data: 177.0 (ꢀCHꢁNꢀ), 28.0 (ꢀ
SMe), 152.2 [C1,
3J(Cꢀ 7], 136.7 [C2, 1J(Cꢀ 85, 2J(Cꢀ
P)ꢁ Pt)ꢁ P)ꢁ
/
H)ꢁ
/
7.3], 8.80 [d, 1H, H6?, J(Hꢀ
7.90 [m, 20H, H4?, H5?
/
H)ꢁ
/
7.3],
recorded at 298 K with a SHIMADZU-160A spectro-
photometer and an AMINCO-BOWMAN spectro-
fluorimeter was used to obtain the luminescence
spectrum of 10ꢀ4 M solutions of 2a and 2b in CH2Cl2
at 298 K.
/
/
/
/
/
/
/
/
/
/
/
5
Hz], 128.4 (C3), 134.1 (C4), 133.0 (C5), 130.1 (C6),
148.3 (C1?), 134.7 (C2?), 122.2 (C3?), 126.5 (C4?), 132.7
(C6?) and four additional doublets centred at ca. 134.4,
131.6, 131.1 and 128.7 ppm due to the four types of
carbon nuclei of the aromatic rings of the PPh3 ligand.
4.1.1. Preparation of [Pt{C6H4ꢀ
SMe)}Cl] (2b)
Cis-[PtCl2(PhCN)2] (100 mg, 2.1ꢄ
suspended in 20 cm3 of toluene and refluxed until
complete dissolution. Then, the ligand (48 mg, 2.1ꢄ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ/2-
/
10ꢀ4 mol) was
31P{1H}-NMR data: 19.34 [1J(Pꢀ
195Pt{1H}-NMR data: ꢀ4461 [1J(Ptꢀ
/
Pt)ꢁ
/
3857.6 Hz].
3858].
/
/
/
P)ꢁ
/
10ꢀ4 mol) was added and the mixture was refluxed for
3 h. The resulting solution was filtered and the brown
filtrate was concentrated to ca. 5 cm3 on a rotary
evaporator. The brown solid formed was collected by
filtration and air-dried. (Yield: 30 mg, 31%). Character-
isation data: Anal. Calc. for: C14H12NClPtS (Found): C,
36.81 (37.03); H, 2.64 (2.60), N, 3.07 (2.99) and S, 7.02
4.2. Crystallography
A brown crystal of [Pt{C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ/2-
SMe)}Cl] (2b) was selected and mounted on a EN-
RAF-Nonius CAD 4 four circle diffractometer. Unit
cell parameter were determined from automatic centring
(6.73)%. MS (FABꢃ): m/zꢁ
n(ꢂCꢁNꢀ)ꢁ
1588 cmꢀ1. UVꢂ
dm3 molꢀ1 cm2)ꢁ
346 (7540); 363 (7846), 431 sh (1347),
466 (1971) and 492 sh (1670). H-NMR data: 2.95 [s,
3H, ꢀ H)ꢁ20], 8.98 [s, 1H, ꢀCHꢁNꢀ
SMe, 3J(Ptꢀ
3J(Ptꢀ 131], 7.47 [d, 1H, H3, J(Hꢀ
H)ꢁ 7.5], 7.35
[t, 1H, H4, 3J(Hꢀ 7.5], 7.51 [t, 1H, H5, 3J(Hꢀ
H)ꢁ H)ꢁ
7.5], 7.67 [dd, 1H, H6, J(Hꢀ
H)ꢁ1.5],
7.75 [d, 1H, H3?, 3J(Hꢀ 7.5], 7.12 [td, 1H, H4?,
H)ꢁ
3J(Hꢀ 7.5, 4J(Hꢀ 1.5], 7.46 [t, 1H, H5?, 3J(Hꢀ
H)ꢁ H)ꢁ
H)ꢁ
7.5] and 7.87 [dd, 1H, H6?, J(Hꢀ
H)ꢁ Pt)ꢁ
1.5, 3J(Hꢀ 41]. 13C{1H}-NMR data: 169.2
(ꢀCHꢁNꢀ), 26.8 (ꢀ
SMe), 148.5 (C1), 130.8 (C3), 134.0
/
421 {Mꢀ
/
(Cl)}ꢃ. IR:
of 25 reflections (in the range 12B
by least-squares method. Intensities were collected with
a graphite monochromatised MoꢂKa radiation using
v ꢂ2U scan-technique. The number of reflections mea-
sured in the range 2.435U 529.988 was 4116, of which
3912 were non-equivalent by symmetry {Rint (on I)ꢁ
0.043} and the number of reflections assumed as
observed, applying the condition I ꢁ2s(I), was 3068.
/
U B218) and refined
/
/
/
/
/
vis data: l (nm) (o in
/
/
1
/
/
/
/
/
/
/
,
/
/
3
/
/
/
H)ꢁ
/
/
/
/
/
/
3
4
/
H)ꢁ
/
7.5, J(Hꢀ
/
/
/
/
/
Three reflections were measured every 2 h as orientation
and intensity control, but no significant intensity decay
was observed. Lorentz-polarisation corrections were
made, but absorption corrections were not.
The structure was solved by Direct methods, using the
SHELXS computer program [28] and refined by full-
matrix least-squares method with the SHELX-97 compu-
ter program [29] using 3912 reflections (very negative
intensities were not assumed). The function minimised
/
/
/
/
/
3
4
/
/
H)ꢁ
/
7.5, J(Hꢀ
/
/
/
/
/
/
/
/
(C4), 131.0 (C5), 135.1 (C6), 155.8 (C1?), 118.1 (C3?),
125.1 (C4?), 131.2(C5?) and 132.6 (C6?), the signals due to
the C2 and C2? atoms were not detected in the 13C{1H}-
NMR spectrum. 195Pt{1H}-NMR data: ꢀ
3708.
/
2
2 2
was SwjjFoj ꢀ
/
jFcj j , where wꢁ
/
[s2(I)ꢃ
/
(0.0684P)2ꢃ
/
2
2
4.1.2. Preparation of [Pt{C6H4ꢀ
SMe)}Cl(PPh3)] (3b)
Complex 2b (60 mg, 1.3ꢄ
10 ml of CH2Cl2 then the stoichiometric amount of PPh3
(34 mg, 1.3ꢄ
10ꢀ4 mol) was added. The reaction
mixture was stirred at room temperature (r.t.) (ca.
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ/2-
0.3429P]ꢀ1 and Pꢁ
/
(jFoj ꢃ2jFcj )/3; f, f? and fƒ were
/
obtained from the literature [30]. All hydrogen atoms
were computed and refined with an overall isotropic
temperature factor using a riding model. The final R(on
F) factor was 0.041, wR(on F2)ꢁ
/
10ꢀ4 mol) was dissolved in
/
/
0.101 and the good-
ness-of-fit was 1.048 for all the observed reflections. The

170
A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ171
/
Table 2
References
Crystallographic data for [Pt{C6H4ꢀ
/
CHꢁ
/
Nꢀ
/
(C6H4ꢀ2-SMe)}Cl] (2b)
/
[1] (a) I. Omae, Applications of Organometallic Compounds, Wiley,
Chichester, UK, 1998;
Formula
Formula weight
T (K)
C14H12ClNPtS
456.85
293(2)
(b) A.K. Klaus, in: A.E. Peters, H.S. Freemann (Eds.), Modern
Colorants: Synthesis and Structure, vol. 3, Academic and Profes-
sional, London, UK, 1995;
Crystal dimensions (mmꢄ
Crystal system
Space group
/
mmꢄ/mm)
0.1ꢄ
/
0.1ꢄ0.2
/
Monoclinic
P21/n
(c) T. Hambley, Coord. Chem. Rev. 166 (1997) 1181;
(d) B. Lippert, Coord. Chem. Rev. 92 (1992) 263.
[2] (a) C. Navarro-Ranninger, I. Lo´pez Solera, V.M. Gonza´lez, J.M.
˚
a (A)
9.671(3)
12.579(9)
11.286(6)
90.0
˚
b (A)
´
Pe´rez, A. .Alvarez-Valdes, A. Martin, P.R. Raithby, J.R. Massa-
˚
c (A)
aꢁg (8)
b (8)
guer, C. Alonso, Inorg. Chem. 35 (1996) 5181;
(b) C.E. Headford, R. Mason, P.R. Ranatunge-Bandarage, B.H.
Robinson, J. Simpson, J. Chem. Soc. Chem. Commun. (1990)
601.
/
96.89(3)
1363.0(13)
4
3
˚
V (A )
Z
[3] (a) J.J. Johnson, J. Sames, J. Am. Chem. Soc. 122 (2000) 6321;
(b) C.R. Baar, H.A. Jenkins, G.P.A. Yap, R.J. Puddephatt,
Organometallics 17 (1998) 4329;
Dcalc (g cmꢀ3
m (mmꢀ1
F(000)
)
2.226
10.623
856
)
(c) C.R. Baar, H.A. Jenkins, M.C. Jennings, G.P.A. Yap, R.J.
Puddephatt, Organometallics 19 (2000) 4870;
(d) C.R. Baar, M.C. Jennings, R.J. Puddephatt, Organometallics
18 (1999) 4373;
URange for data collection (8)
h, k, l ranges
2.43ꢂ
135
15k 5
05l 515
4116
/
29.98
h 5
17,
ꢀ
ꢀ/
/
/
/
13,
/
/
/
/
(e) C.R. Baar, L.P. Carbray, M.C. Jennings, R.J. Puddephatt, J.
Am. Chem. Soc. 122 (2000) 176;
Number of collected reflections
Number of unique reflections
Number of data
3912 [Rint
3912
ꢁ/0.0439]
(f) C.R. Baar, M.C. Jennings, J.J. Vittal, R.J. Puddephatt,
Organometallics 19 (2000) 4150;
Number of parameters
Goodness-of-fit on F2
163
1.048
(g) C.R. Baar, L.P. Carbray, M.C. Jennings, R.J. Puddephatt,
Organometallics 19 (2000) 2482;
Final R indices [I ꢁ
Final R indices (all data)
Largest difference peak and hole (e Aꢀ3
/
2s(I)]
R1ꢁ
R1ꢁ
0.884 and ꢀ
/
0.0417, wR2ꢁ
0.0628, wR2ꢁ
0.620
/
0.1015
0.1100
(h) C.R. Baar, L.P. Carbray, M.C. Jennings, R.J. Puddephatt, J.J.
Vittal, Organometallics 20 (2001) 408;
/
/
)
/
(i) P. Wadhwani, D. Bandoyopadhyay, Organometallics 19 (2000)
4435.
[4] (a) V.W.W. Yam, K.M.C. Wong, N. Zhu, J. Am. Chem. Soc. 124
(2002) 6506;
final R values as well as further details of the refinement
of the structure are presented in Table 2.
(b) M. Hissler, J.E. Mc Garrah, W.B. Connick, D.K. Geiger, S.D.
Cummings, R. Eisenberg, Coord. Chem. Rev. 208 (2000) 115 (and
references therein);
(c) M. Maestry, Coord. Chem. Rev. 111 (1991) 117;
(d) M.M. Mdleleni, J.S. Bridgewater, R.J. Watts, P.C. Ford,
Inorg. Chem. 34 (1995) 2334;
(e) F. Neve, A. Crispini, S. Campagna, Inorg. Chem. 36 (1997)
6150;
5. Supplementary material
(f) S.W. Lai, M.C.W. Chan, K.K. Cheung, C.M. Che, Organo-
metallics 18 (1999) 3327;
Crystallographic data for the structural analyses have
been deposited at the Cambridge Crystallographic Data
Centre, CCDC, no. 196565. Copies of this information
can be obtained from The Director, CCDC, 12 Union
(g) S.W. Lai, M.C.W. Chan, T.C. Cheung, S.M. Peng, C.M. Che,
Inorg. Chem. 38 (1999) 913;
(h) T.C. Cheung, K.K. Cheung, S.M. Peng, C.M. Che, J. Chem.
Soc. Dalton Trans. (1996) 645.
Road, Cambridge CB2 1EZ, UK (Fax: ꢃ44-1233-
/
[5] R.G. Pearson, J. Am. Chem. Soc. 85 (1963) 3533.
[6] (a) S. Chattopadhyay, C. Sinha, P. Basu, A. Chakravorty, J.
Organomet. Chem. 414 (1991) 421;
336033; e-mail: deposit@ccdc.ac.uk or http://
www.ccdc.cam.ac.uk).
(b) S. Chattopadhyay, C. Sinha, P. Basu, A. Chakravorty,
Organometallics 10 (1991) 1135.
[7] (a) X. Riera, A. Caubet, C. Lo´pez, V. Moreno, X. Solans, M.
Font-Bard´ıa, Organometallics 19 (2000) 1384;
(b) X. Riera, C. Lo´pez, A. Caubet, V. Moreno, X. Solans, M.
Font-Bard´ıa, Eur. J. Inorg. Chem. (2001) 2135.
[8] Characterisation data: Anal. Calc. for C7H9NCl2PtS (Found): C,
20.75 (20.84); H, 2.24 (2.28); N, 3.46 (3.30) and S, 8.91 (8.27)%.
Acknowledgements
We acknowledge the financial support given to us by
the Ministerio de Ciencia y Tecnolog´ıa of Spain
(projects: BQU2000-0652 and PB98-1236) and to the
Generalitat de Catalunya (2001-SGR-0054) for financial
support. We are also grateful to Mrs. Mertxe Encabo
(Department of Analytical Chemistry) for the facilities
given to run the luminescence spectra.
IR: 3250 cmꢀ1 {n(NꢀH)}. 1H-NMR data (in CDCl3, numbering
/
of the atoms refers to those shown in Scheme 1 for the 1,2-
disubtituted phenyl ring holding the SMe group): 3.45 and 3.41
[2H, NH2, 3J(Ptꢀ
6.61 [d, 1H, H2?, 3J(Hꢀ
6.97 [t, 1H, H5?, 3J(Hꢀ
H)ꢁ
8.2].
/
H)ꢁ
H)ꢁ
8.2] and 7.10 [d, 1H, H6?, 3J(Hꢀ
/
22], 2.95 [s, 3H, ꢀ
/
SMe, 3J(Ptꢀ
H)ꢁ
H)ꢁ
/
H)ꢁ
/
40],
/
/
8.2], 6.41[t, 1H, H3?, 3J(Hꢀ
/
/
8.2],
/
/
/
/

A. Caubet et al. / Journal of Organometallic Chemistry 669 (2003) 164ꢂ
/171
171
[9] C. Lo´pez, S. Pe´rez, X. Solans, M. Font-Bard´ıa, J. Organomet.
Chem. 650 (2002) 258.
Trans. (1972) 1178.;
(d) E.C. Constable, R.P.G. Henney, T.A. Leese, D.A. Tocher,
Chem. Commun. (1990) 513.
[10] J. Bravo, C. Cativela, R. Navarro, E.P. Urriolabeitia, J.
Organomet. Chem. 650 (2002) 157.
[11] The least-squares equation of the plane defined by the atoms: N,
[19] (a) S.W. Lai, H.W. Lam, W. Lu, K.K. Cheung, C.M. Che,
Organometallics 21 (2002) 226;
S, Cl and C(1) is: (ꢀ
/
0.6194)XOꢃ
/
(0.5177)YOꢃ
/
(0.5903)ZOꢁ
/
(b) K.H. Wong, M.C.W. Chan, C.M. Che, Chem. Eur. J. 5 (1999)
2845;
8.0855. Deviations from the main plane are as follows: N,
˚
0.034 A.
ꢃ
/
0.036; S, ꢀ
/
0.028; Cl, ꢃ
/
0.025 and C(1), ꢀ
/
(c) W. Lu, B.X. Mi, M.C.W. Chan, Z. Hui, N. Zhu, S.T. Lee,
C.M. Che, Chem. Commun. (2002) 206.;
[12] T.H. Allen, O. Kennard, Chem. Des. Automat. News 8 (1993)
146.
(d) W. Lu, W. Zhu, C.M. Che, Chem. Commun. (2002) 900.
[20] H. Jude, J.A. Bauer, W.B. Connick, Inorg. Chem. 41 (2002) 2275.
[21] The least-squares equation of the plane defined by all the atoms
[13] (a) E. Wehman, G. van Koten, C.T. Knaap, H. Ossor, M. Pfeffer,
A.L. Spek, Inorg. Chem. 27 (1988) 4409;
(b) A.G. Orpen, L. Brammer, F.H. Allen, O. Kennard, D.G.
Watson, R. Taylor, J. Chem. Soc. Dalton Trans. (1989) S1.
[14] The least-squares equation of the plane defined by the atoms
involved in the tricyclic system is (ꢀ
(0.5649)ZOꢁ7.7492. Maxima deviations were found for C(4):
0.070 and C(9): 0.084 A.
/
0.6540)XOꢃ
/
(0.5032)YOꢃ
/
/
˚
ꢀ/
forming the five-membered platinacycle is: (ꢀ
(0.5055)YOꢃ(0.5650)ZOꢁ7.8174. Deviations from the plane
are as follows: Pt, ꢀ0.019; N, ꢀ0.034; C(1), ꢀ0.009; C(6),
/
0.652)XOꢃ
/
[22] C. Janiak, J. Chem. Soc. Dalton Trans. (2000) 3985 and references
therein.
/
/
/
/
/
[23] (a) J. Albert, M. Go´mez, J. Granell, J. Sales, X. Solans,
Organometallics 9 (1990) 1405;
˚
ꢀ
/
0.008 and C(7), 0.033 A.
[15] The least-squares equation of the plane defined by the atoms Pt, S,
N, C(8) and C(13) is: (ꢀ0.6389)XOꢃ(0.5258)YOꢃ(0.5615)ZOꢁ
8.0630. Deviations from the plane are as follows: Pt, 0.012; S,
(b) J. Albert, R.M. Ceder, J. Granell, J. Sales, Organometallics 11
(1992) 1536;
/
/
/
/
(c) Y.J. Wu, L. Ding, H.X. Wang, Y.H. Liu, H.Z. Yuan, X.A.
Mao, J. Organomet. Chem. 535 (1997) 49;
˚
ꢀ
/
0.024; N, ꢀ
/
0.026; C(8), ꢃ
/
0.028 and C(13), ꢀ0.012, A.
/
[16] (a) A. Bondi, J. Phys. Chem. 68 (1964) 441;
(b) A.I. Kitaigorodskii, Molecular Crystals and Molecules,
Academic press, London, UK, 1973.
(d) A. Caubet, C. Lo´pez, R. Bosque, X. Solans, M. Font-Bard´ıa,
J. Organomet. Chem. 557 (1999) 292.
[24] A.J. Deeming, I.P. Rothweel, M.B. Hursthouse, L. New, J. Chem.
Soc. Dalton Trans. (1978) 1490.
[17] (a) M.A. Langfredi, A. Tiripiccio, G. Natile, F. Gasparrini, B.
Galli, Cryst. Struct. Commun. 6 (1979) 611;
[25] (a) J. Vicente, A. Arcas, D. Bautista, P.G. Jones, Organometallics
16 (1997) 2129;
(b) A.G. Constable, W.S. Mc Donald, B.L. Shaw, J. Chem. Soc.
Dalton Trans. (1975) 1109.;
(b) J. Vicente, J.A. Abad, A. Frankland, C. Ram´ırez de Arellano,
Chem. Eur. J. 5 (1995) 3066.
(c) G. Natile, F. Gasparrini, D.M. Misti, G. Perego, J. Chem. Soc.
Dalton Trans. (1997) 1747.;
[26] A. Adachi, M.A. Baldo, S.R. Forrest, S. Lamansky, M.E.
Thompson, Appl. Phys. Lett. 78 (2001) 1622.
[27] J.H. Price, A.N. Williamson, R.F. Schramm, B. Wayland, Inorg.
Chem. 11 (1972) 1280.
(d) K.V. Katti, Y.W. Ge, P.R. Sing, L. Date, S.V. Barnes,
Organometallics 13 (1994) 541;
(e) S. Pe´rez, R. Bosque, C. Lo´pez, X. Solans, M. Font-Bard´ıa, J.
Organomet. Chem. 625 (2001) 67;
[28] G.M. Sheldrick, SHELXS. A Computer Program for Determina-
tion of Crystal Structures, University of Gottingen, Germany,
(f) G. Codina, A. Caubet, C. Lo´pez, V. Moreno, E. Molins, Helv.
Chim. Acta 82 (1999) 1025.
¨
1997.
[29] G.M. Sheldrick, SHELX-97. A Computer Program for Determina-
tion of Crystal Structures, University of Gottingen, Germany,
¨
[18] (a) E. Ratilla, B.K. Scott, M.S. Moxness, N.M. Kostic, Inorg.
Chem. 29 (1990) 918;
(b) J.A. Bailey, V.M. Miskovskii, H.B. Gray, Inorg. Chem. 32
(1993) 369;
1997.
[30] International Tables of X-Ray Crystallography, vol. IV, Kynoch
(c) B. Jovanovic, L.J. Manojlovic, K. Muir, J. Chem. Soc. Dalton
Press, pp. 99ꢂ100 and 104.
/