A comparative study of metallating agents in the synthesis of [C,N,N′]-cycloplatinated compounds derived from biphenylimines

Article abstract of DOI:10.1016/j.jorganchem.2006.01.011

The reactions of ligands 4-C₆H₅C₆H ₄CHNCH₂CH₂NMe₂ (1a) and 2-C ₆H₅C₆H₄CHNCH₂CH ₂NMe₂ (1b) in front of cis-[PtCl₂(dmso) ₂] or cis-[PtPh₂(SMe₂)₂] produced compounds [PtCl₂{4-C₆H₅C₆H ₄CHNCH₂CH₂NMe₂}] (2aCl) and [PtCl₂{2-C₆H₅C₆H ₄CHNCH₂CH₂NMe₂}] (2bCl) or [PtPh₂{4-C₆H₅C₆H ₄CHNCH₂CH₂NMe₂}] (2aPh) and [PtPh₂{2-C₆H₅C₆H ₄CHNCH₂CH₂NMe₂}] (2bPh). From all these compounds, the corresponding cyclometallated [C,N,N′] platinum(II) compounds 3aCl, 3bCl, 3aPh and 3bPh were obtained although under milder conditions and with higher yields for the phenyl derivatives. The reaction of compounds 3aPh and 3bPh with methyl iodide gave cyclometallated [C,N,N′] platinum(IV) compounds 4aPh and 4bPh of formula [PtMePhI{C₆H ₅C₆H₃CHNCH₂CH₂NMe ₂}]. Compounds 3aCl and 3bCl containing a chloro ligand, although unreactive towards methyl iodide, undergo oxidative addition of chlorine to produce the corresponding platinum(IV) compounds [PtCl₃{4-C ₆H₅C₆H₃CHNCH₂CH ₂NMe₂}] (6aCl and 6bCl). All compounds were characterised by NMR spectroscopy and crystal structures of compounds 3bCl and 6bCl are also reported.

Full text of DOI:10.1016/j.jorganchem.2006.01.011

Journal of Organometallic Chemistry 691 (2006) 1897–1906
www.elsevier.com/locate/jorganchem
A comparative study of metallating agents in the synthesis of
[C,N,N0]-cycloplatinated compounds derived from biphenylimines
a,
b
b
*
`
´
Margarita Crespo , Merce Font-Bardıa , Xavier Solans
a
`
Departament de Quı´mica Inorganica, Universitat de Barcelona, Diagonal 647, 08028 Barcelona, Spain
´
b
` `
Departament de Cristallografia, Mineralogia i Diposits Minerals, Universitat de Barcelona, Martı i Franques s/n, 08028 Barcelona, Spain
Received 7 December 2005; received in revised form 9 January 2006; accepted 9 January 2006
Available online 14 February 2006
Abstract
The reactions of ligands 4-C6H5C6H4CHNCH2CH2NMe2 (1a) and 2-C6H5C6H4CHNCH2CH2NMe2 (1b) in front of cis-[PtCl2-
(dmso)2] or cis-[PtPh2(SMe2)2] produced compounds [PtCl2{4-C6H5C6H4CHNCH2CH2NMe2}] (2aCl) and [PtCl2{2-C6H5C6H4-
CHNCH2CH2NMe2}] (2bCl) or [PtPh2{4-C6H5C6H4CHNCH2CH2NMe2}] (2aPh) and [PtPh2{2-C6H5C6H4CHNCH2CH2NMe2}]
(2bPh). From all these compounds, the corresponding cyclometallated [C,N,N0] platinum(II) compounds 3aCl, 3bCl, 3aPh and 3bPh
were obtained although under milder conditions and with higher yields for the phenyl derivatives. The reaction of compounds 3aPh
and 3bPh with methyl iodide gave cyclometallated [C,N,N0] platinum(IV) compounds 4aPh and 4bPh of formula [PtMePhI-
{C6H5C6H3CHNCH2CH2NMe2}]. Compounds 3aCl and 3bCl containing a chloro ligand, although unreactive towards methyl iodide,
undergo oxidative addition of chlorine to produce the corresponding platinum(IV) compounds [PtCl3{4-C6H5C6H3-
CHNCH2CH2NMe2}] (6aCl and 6bCl). All compounds were characterised by NMR spectroscopy and crystal structures of compounds
3bCl and 6bCl are also reported.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Platinum; Imines; Biphenyl; Cyclometallation; Crystal structure
1. Introduction
bond activation [4]. When [PtCl2(dmso)2] is used, electro-
philic substitution on the aromatic carbon with release of
HCl takes place while oxidative addition followed by
reductive elimination of methane or benzene occurs for
the other substrates.
Different synthetic strategies have been reported in the
synthesis of [C,N,N0] cyclometallated compounds including
the use of a variety of metallating substrates such as
cis-[PtCl2(dmso)2] [1], [Pt2Me4(l-SMe2)2] [2] and cis-
[PtPh2(SMe2)2] [3] among others. For all these systems,
the labile sulfoxide or sulfide ligands are easily replaced
by the two nitrogen atoms of the ligands leading to isola-
tion of [N,N0] coordination compounds which are precur-
sors for the cyclometallated derivatives. Different
mechanisms may operate in each case for the actual C–H
In order to compare the ease of formation of both [N,N0]
and [C,N,N0] platinum(II) compounds as well as the
reactivity of the resulting compounds towards oxidative
addition of alkyl halides, we now report the reactivity
of ligands 4-C6H5C6H4CHNCH2CH2NMe2 (1a) and
2-C6H5C6H4CHNCH2CH2NMe2 (1b) containing 2- or
4-biphenyl groups in front of cis-[PtCl2(dmso)2] and cis-
[PtPh2(SMe2)2] in order to complete the results recently
reported involving [Pt2Me4(l-SMe2)2] as metallating sub-
strate [5]. In addition, these ligands allow to consider the
influence in these reactions of the phenyl substituent in 2-
or 4-positions.
*
Corresponding author. Tel.: +34 934039132; fax: +34 934907725.
E-mail address: margarita.crespo@qi.ub.es (M. Crespo).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.01.011

1898
M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
2. Results and discussion
2.1. [N,N0] platinum compounds
erisation process was obtained when 2aCl was refluxed in
dichloromethane for 10 h since in the H NMR spectrum
1
of the final mixture new signals corresponding to the E iso-
mer were observed, the ratio E:Z being 0.8:1. Under the
same experimental conditions, isomerisation was not
observed for the 2-biphenylderivative 2bCl in agreement
with the higher crowding in the platinum coordination
sphere arising from the presence of a phenyl substituent
in ortho.
Ligands 1a and 1b were prepared as the E conformer
following the reported procedure [5] and their reactions
with cis-[PtCl2(dmso)2] and cis-[PtPh2(SMe2)2] were stud-
ied. Previous work [6] indicated that dimethylsulfide is a
worse leaving ligand than dimethylsulfoxide for plati-
num(II) and for this reason cis-[PtCl2(dmso)2] was used
as starting material. When equimolar amounts of this
compound and ligand 1a or 1b were refluxed in methanol
during 4 h, the corresponding compounds [PtCl2{4-
C6H5C6H4CHNCH2CH2NMe2}] (2aCl) and [PtCl2{2-
C6H5C6H4CHNCH2CH2NMe2}] (2bCl) were obtained in
good yields (see Scheme 1). These compounds although
scarcely soluble in most common solvents could be charac-
On the other hand, dialkylsulfide ligands have been
reported to be readily displaced from diarylplatinum(II)
complexes [7] and accordingly, the reactions of ligands 1a
or 1b with cis-[PtPh2(SMe2)2] proceed under milder condi-
tions than those reported for cis-[PtCl2(dmso)2]. The reac-
tions carried out in acetone at room temperature produced
compounds [PtPh2{4-C6H5C6H4CHNCH2CH2NMe2}] (2aPh)
and [PtPh2{2-C6H5C6H4CHNCH2CH2NMe2}] (2bPh) in
good yields. The obtained compounds are soluble in most
1
terised by H and 195Pt NMR spectra. Evidence of coordi-
1
nation of both nitrogen atoms to platinum is obtained from
the fact that both methylamine and imine protons are cou-
pled to 195Pt nucleus (J(H–Pt) = 36.0 and 59.0 Hz (2aCl)
and 31.0 and 58.4 Hz (2bCl), respectively). As previously
noticed for analogous systems [1f], a Z conformation
around the C@N bond is adopted with the imine proton
close to the platinum nucleus which is evidenced by the
downfield shift of the imine signal (d = 9.56 (2aCl) and
9.64 (2bCl)). This fact suggests that coordination of a
bidentate ligand to a PtCl2 moiety produces a conforma-
tional change from the most stable E conformation of
the free ligand to the Z and, consequently, Z–E isomerisa-
tion should precede the cyclometallation step as previously
reported for analogous systems [1f]. Evidence of this isom-
common solvents and were characterised by H, 13C and
195Pt NMR spectroscopies. In addition 2D-NOESY and
1H–13C gHSQC (2aPh) NMR spectra were also taken. As
for compounds above, dimethylamine protons are coupled
to platinum, and in agreement with the higher trans influence
of phenyl versus chloro ligand, the J(H–Pt) values are in this
case smaller. 2D-NOESY experiments suggest an E confor-
mation across the C@N bond which is the most favoured
conformation of the free ligands as well as the adequate
arrangement for producing cyclometallation at the biphenyl
group. Although this result suggests that steric crowding in
the coordination sphere of the platinum(II) centre is not
too severe, isomerisation to the less congested Z form takes
place in solution at room temperature. This process occurred
c
b
c
b
R4
a
a
R2
N
NMe2
N
Cl
Pt
NMe2
d
c
b
d
Pt
a
R2
R2
C
N
NMe2
(iii)
(ii)
(i)
Cl
d
H
2
3
Cl
Cl
2
3
Pt
5
5
Cl
Cl
4
4
H
R4
R4
2aCl R2 = H; R4 = Ph
2bCl R2 = Ph; R4 = H
NMe2
C
N
3aCl R2 = H; R4 = Ph
3bCl R2 = Ph; R4 = H
6aCl R2 = H; R4 = Ph
6bCl R2 = Ph; R4 = H
R2
c
b
R4
c
b
a
a
N
Me
Pt
I
1a R2 = H; R4 = Ph
1b R2 = Ph; R4 = H
N
NMe2
NMe2
d
H
d
d
c
b
Pt
a
R2
R2
C
N
R2
NMe2
Ph
Ph
2
3
2
2
(v)
Pt
(vi)
6
3
3
5
(iv)
5
Ph
Ph
4
R4
4
R4
5
4
R4
2aPh R2 = H; R4 = Ph
2bPh R2 = Ph; R4 = H
3aPh R2 = H; R4 = Ph
3bPh R2 = Ph; R4 = H
4aPh R2 = H; R4 = Ph
4bPh R2 = Ph; R4 = H
Scheme 1. (i) +cis-[PtCl2(dmso)2], MeOH, reflux, 4 h; (ii) +Na(CH3COO), MeOH, reflux, 12 h; (iii) +Cl2 in CH3CN, RT, 10 min; (iv) +cis-
[PtPh2(SMe2)2], acetone, RT, 30 min; (v) toluene, reflux, 6h; (vi) MeI, acetone, RT, 30 min.

M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
1899
e,e'
f,f'
faster and in a larger extension for the 2-biphenyl derivative
Hg
H
d,d'
NMe2
R2
R2
2bPh since after 4 h the ratio Z:E was 2:1 while for 2aPh after
48 h the ratio Z:E was 0.8:1. In both cases, the E to Z isom-
erisation is evidenced by a decrease in J(H–Pt) value of the
imine proton from 46.4 (2aPh) or 43.4 Hz (2bPh) to 24.0
and 27.2 Hz, respectively. Such an isomerisation has not
been observed previously for compounds such as [PtPh2-
{C6H5CHNCH2CH2NMe2}] [3] or methyl derivatives [PtMe2-
{C6H5C6H4CHNCH2CH2NMe2}] [5] which suggests that
the combined effect of two phenyl ligands and a dangling
biphenyl group in 2aPh and 2bPh increases the steric bulk
in the coordination sphere which is minimised by conforma-
tional changes.
C
N
C
N
Mea
Pt
NMe2
Pt
+ MeI
Meb
Me
Mec
Me
I
Acetone
RT, 10 min.
R4
R4
5aMe R2 = H; R4 = Ph
5bMe R2 = Ph; R4 = H
2aMe R2 = H; R4 = Ph
2bMe R2 = Ph; R4 = H
ð1Þ
2.2. Cyclometallated [C,N,N0] platinum compounds
Compounds 2 containing the imine ligand coordinated
through both nitrogen atoms to platinum(II) might be pre-
cursors of cyclometallated [C,N,N0] platinum(II) com-
pounds. Intramolecular C–H bond activation may lead to
formation of five-membered metallacycles and, in the case
of compounds derived from ligand 1b, formation of a
seven-membered metallacycle, as shown in Fig. 1, can also
be considered.
Analyses of the d (195Pt) values show that those obtained
for 2aPh and 2bPh are very close to the previously reported
for analogous [PtMe2(NN0)] compounds [5], that is in the
range expected for a platinum(II) centre coordinated to
two nitrogen and two carbon atoms [8]. However, when C
donor ligands (methyl or phenyl) are replaced by chloro
ligands as in 2aCl and 2bCl, the 195Pt resonance is downfield
shifted. In order to gain more insight into the chemistry of
these compounds as well as to evaluate whether d (195Pt) val-
ues can be taken as a measureof the reactivity at the platinum
centre, the reactions of compounds 2aCl, 2bCl, 2aPh and
2bPh with methyl iodide were studied along with those of
methyl analogues [PtMe2{4-C6H5C6H4CHNCH2CH2NMe2}]
(2aMe) and [PtMe2{2-C6H5C6H4CHNCH2CH2NMe2}]
(2bMe) previously described. As shown in Reaction (1),
compounds 2aMe and 2bMe reacted with methyl iodide
under very mild conditions to produce an oxidative addition
process leading to platinum(IV) compounds 5aMe and
5bMe which were characterised by NMR spectroscopy and
analytical data. Under the same conditions or even using
longer reaction times up to 48 h, compounds 2aCl and
2bCl were recovered unaltered; their lower tendency to
experiment an oxidative addition process can be related to
their lower electronic density at the platinum(II) centre evi-
denced by their d (195Pt) values. Unfortunately, the reactions
of 2aPh and 2bPh with methyl iodide did not produce clear
results leading to some decomposition process evidenced
by formation of metallic platinum and aldehyde. When these
reactions were monitored by 1H NMR spectroscopy, in the
early stages of the reaction, resonances that could be tenta-
tively assigned to platinum(IV) derivatives were observed
[9] although overlapped with those corresponding to the
platinum(II) precursors. After a short time, these signals dis-
appear to give a complex mixture in which only the corre-
sponding cation C6H5C6H4CHNCH2CH2NMeþ3 could be
identified by a peak at 267 in the FAB-mass spectra. These
results suggest that, according to the 195Pt NMR results,
the electronic density at the metal centre for diphenylplati-
num(II) compounds is high enough as to allow for oxidative
addition to take place, however, the steric crowding resulting
from the presence of two phenyl ligands and a biphenyl moi-
ety along with the increased bulk of octahedral versus
square-planar platinum centre [10] led to decomposition of
the resulting compounds
The most widely used conditions for converting com-
pounds analogous to 2aCl and 2bCl into cycloplatinated
derivatives are refluxing for several hours in either toluene
or in a donor solvent such as methanol or ethanol, in some
cases in the presence of an external base which favours the
formal elimination of HCl [1]. Following the conditions
used in the preparation of [PtCl(C6H4CHNCH2-
CH2NMe2)] [1f], 2aCl was treated with an equimolar
amount of sodium acetate in refluxing methanol during
12 h to produce [PtCl{4-C6H5C6H3CHNCH2CH2NMe2}]
(3aCl) while formation of [PtCl{2-C6H5C6H3CHN-
CH2CH2NMe2}] (3bCl) from 2bCl under the same condi-
tions required a reaction time of 48 h and careful control
of the temperature in order to avoid formation of metallic
platinum. In both cases, the yield obtained for metallation
at the biphenyl group is slightly lower than that obtained
for the phenyl derivative [PtCl(C6H4CHNCH2CH2NMe2)]
[1f]. The process requires an initial step in which Z to E
imine isomerisation brings the aryl ring closer to platinum
followed by the actual intramolecular C–H bond activation
which in both cases lead to five-membered metallacycles.
Compounds 3aCl and 3bCl depicted in the scheme were
characterised by 1H, 13C and 195Pt NMR spectra and
endo 5 memb.
NMe2
C
H
N
Pt
X
X
endo 7 memb.
Fig. 1. Metallation sites for compounds derived from ligand 1b.

1900
M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
elemental analyses, and 3bCl was also characterised crys-
tallographically. The J(H–Pt) value for the methylamine
geometry assuming that the oxidative addition of methyl
iodide takes place in trans and that no further isomerisa-
tion of the resulting platinum(IV) compound occurs [12].
The J(H–Pt) value for the methylplatinum and the dimeth-
ylamino groups are in the range expected for a plati-
num(IV) compound and the d (195Pt) values appear
downfield shifted when compared to the platinum(II) pre-
cursors. The easy formation of [C,N,N0] platinum(IV)
compounds from 3aPh and 3bPh is a similar result to
that previously reported for the methyl analogues
[PtMe{C6H5C6H3CHNCH2CH2NMe2}] [5]. The success
of this reaction compared with the poor results obtained
for the [N,N0] coordination compounds 2aPh and 2bPh
can be related to the higher stability imparted by the terd-
entate coordination of the ligand in 3aPh and 3bPh.
3
proton decreases from 2aCl or 2bCl to the corresponding
cyclometallated derivatives 3aCl and 3bCl as a result of
the higher trans influence of aryl versus chloro ligands.
Conversely, an increase in the coupling constant of the
imine proton to platinum is observed upon cyclometalla-
tion. In addition, the coupling to platinum of the aromatic
proton adjacent to the metallation site (H5) and the pres-
ence of signals corresponding to eight Caromatic–H atoms
in the 13C NMR spectra confirm that metallation took
place.
Compounds [PtPh{4-C6H5C6H3CHNCH2CH2NMe2}]
(3aPh) and [PtPh{2-C6H5C6H3CHNCH2CH2NMe2}] (3bPh)
were obtained after refluxing a toluene solution of 2aPh or
2bPh, respectively, during 6 h. Although some decomposi-
tion took place, as evidenced by formation of metallic plati-
num, the cyclometallated compounds were isolated in good
yield in a process involving intramolecular activation of a
Finally, a new cyclometallated platinum(IV) compound
[PtCl3{2-C6H5C6H3CHNCH2CH2NMe2}] (6bCl), formally
arising from chlorine addition to 3bCl was obtained unex-
pectedly in an attempt to crystallise 2bCl directly from
equimolar amounts of cis-[PtCl2(dmso)2] and 1b mixed in
dichloromethane. The structure resolution (see below) of
the crystals obtained after slow evaporation along one
week reveals the formation of platinum(IV) compound
6bCl. Although oxidative addition reactions have been
extensively performed on square-planar organoplatinum
species containing nitrogen ligands [12], relatively few
examples of cyclometallated platinum(IV) compounds
obtained by halogen addition have been reported [13]. On
the other hand, several platinum(IV) cyclometallated com-
pounds with a fac-PtCl3 arrangement have been obtained
through deoxygenation of coordinated dimethylsulfoxide
[6]. In agreement with those results, formation of 6bCl in
dichloromethane could arise from oxidation of plati-
num(II) to platinum(IV) along with reduction of dmso to
SMe2. However, attempts to obtain compound 6bCl in a
preparative scale from cis-[PtCl2(dmso)2] and 1b in dichlo-
romethane were unsuccessful since only compound 2bCl
and a small amount of 2-biphenylcarboxaldehyde were
Caromatic–H bond along with elimination of benzene [3]. As
for compounds described above in both cases five-membered
metallacycles are formed leading to a [C,N,N0] cyclometal-
lated compounds. Compounds 3aPh and 3bPh (see Scheme
1) were characterised by elemental analyses and NMR spec-
tra (1H, 13C, 195Pt and gHSQC). The coupling constant of the
imine proton to platinum increases slightly from compounds
2aPh and 2bPh (E conformers) to the corresponding cyclo-
metallated compounds as a result of the formation of a
metallacycle. The presence of nine cross-peak signals in the
1
aromatic region of the H–13C heterocorrelation spectra
supports the proposed structures. Metallation of the
dichloro compounds produces a large upfield shift of the
195Pt resonance (ca. 1200 ppm) as a result of replacing a
chloro ligand for an aryl group. However, the analogous
process at the diphenyl compounds produces only a moder-
ate upfield shift (ca. 160 ppm) since in this case there is no
change in the donor atoms set at the coordination sphere
of platinum.
1
The reactivity with methyl iodide was also tested for all
the obtained cyclometallated platinum(II) compounds and
striking differences were obtained between compounds con-
taining a chloro or a phenyl ligand in spite of the fact that d
detected in the H NMR spectra of the resulting mixture.
The reactions of 3aCl and 3bCl with chlorine in acetoni-
trile were carried out following the procedure reported in
the literature [13a] and, as depicted in the scheme, yielded
compounds 6aCl and 6bCl. These were characterised by
1H NMR and ES-Mass spectra. For both compounds,
the J(H–Pt) value obtained for the imine proton (ca.
100 Hz) is smaller than that observed for the platinum(II)
precursors (ca. 140 Hz) in agreement with the higher oxida-
tion state of the platinum centre. The 1H NMR of 6bCl was
coincident with that of the crystals obtained but, although
it is confirmed that oxidative addition of chlorine to com-
pounds 3aCl and 3bCl is possible, the mechanism of the
unexpected formation of crystals of 6bCl remains unclear.
(
195Pt) values are in the same range for these two types of
compounds. Compounds 3aCl and 3bCl were recovered
unaltered after treating their acetone solutions with a large
excess of methyl iodide during 48 h. On the other hand,
both 3aPh and 3bPh reacted with methyl iodide to produce
an oxidative addition process leading to cyclometallated
platinum(IV) compounds [PtMePhI{4-C6H5C6H3CHN-
CH2CH2NMe2}] (4aPh) and [PtMePhI{2-C6H5C6H3-
CHNCH2CH2NMe2}] (4bPh) which were characterised
by NMR spectroscopy, FAB mass spectra and analytical
data. In particular 2D-NOESY experiments in which the
methyl-platinum resonance show a cross-peak with only
one of the two diastereotopic NMe2 resonances support
the proposed structure (see Scheme 1) in which the methyl
ligand is in an axial position [11]. This is the expected
2.3. Crystal structures
Suitable crystals of 3bCl and 6bCl were grown in
acetone and dichloromethane, respectively. The crystal

M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
1901
Table 1
hedral coordination with the tridentate ligand in a meridi-
onal arrangement is displayed.
˚
Selected bond lengths (A) and angles (ꢁ) with estimated standard
deviations
In both cases the metallacycles are approximately planar
and nearly coplanar with both the metallated phenyl and
the mean coordination plane. Bond lengths and angles
are very similar for 3bCl and 6bCl, in agreement with a pre-
vious comparison between platinum(II) and platinum(IV)
analogues [13a], and to those reported for [PtMe{2-
C6H5C6H3CHNCH2CH2NMe2}] [5]. Most bond angles at
platinum are close to the ideal value of 90ꢁ, and the small-
est angles correspond to those involving the ligand: ‘‘bite’’
angles C(phenyl)–Pt–N of 81.1(3)ꢁ (3bCl) and 80.2(2)ꢁ
(6bCl) and N(1)–Pt–N(2) of 83.5(2)ꢁ (3bCl and 6bCl).
As reported for analogous compounds [5], the dihedral
angle between both phenyl groups of the metallated 2-biphe-
nyl fragments suggests that the phenyl substituent in the
ortho position produces a congestion in the platinum coordi-
nation sphere which is minimised by rotation around the C–
C bond. The obtained values 41.0(4)ꢁ (3bCl) and 49.7(4)ꢁ
(6bCl) are in the same range than those previously reported
for [PtMe{2-C6H5C6H3CHNCH2CH2NMe2}] (43.5(2)ꢁ)
and [PtMe{2-C6H5C6H4CHNCH2Ph}PPh3] (49.9(3)ꢁ).
Compound 3bCl
Pt–C(1)
Pt–N(1)
N(1)–C(13)
N(2)–C(15)
C(6)–C(13)
2.009(6)
1.967(6)
1.292(8)
1.486(12)
1.436(10)
Pt–Cl
Pt–N(2)
N(1)–C(14)
C(1)–C(6)
C(14)–C(15)
2.302(2)
2.168(7)
1.441(10)
1.425(9)
1.373(12)
C(1)–Pt–N(1)
N(1)–Pt–N(2)
81.1(3)
83.5(2)
C(1)–Pt–Cl
Cl–Pt–N(2)
98.8(2)
96.66(18)
Compound 6bCl
Pt–N(1)
Pt–N(2)
1.982(5)
2.300(6)
2.324(2)
1.243(8)
1.395(16)
1.604(12)
1.455(9)
Pt–C(11)
Pt–Cl(3)
Pt–Cl(2)
N(1)–C(14)
N(2)–C(17)
C(11)–C(12)
2.039(7)
2.314(2)
2.329(2)
1.500(8)
1.489(10)
1.407(9)
Pt–Cl(1)
N(1)–C(13)
N(2)–C(16)
N(2)–C(15)
C(12)–C(13)
N(1)–Pt–C(11)
N(1)–Pt–Cl(3)
N(2)–Pt–Cl(3)
N(2)–Pt–Cl(1)
N(1)–Pt–Cl(2)
N(2)–Pt–Cl(2)
80.2(2)
90.08(17)
92.2(2)
96.58(16)
88.69(16)
91.6(2)
N(1)–Pt–N(2)
C(11)–Pt–Cl(3)
C(11)–Pt–Cl(1)
Cl(3)–Pt–Cl(1)
C(11)–Pt–Cl(2)
Cl(1)–Pt–Cl(2)
83.5(2)
87.30(18)
99.76(19)
91.61(9)
88.53(18)
89.61(9)
2.4. Conclusions
structures are composed of discrete molecules separated by
van der Waals interactions. Selected bond lengths and
angles are given in Table 1 and molecular views are shown
in Figs. 2 and 3.
In both cases the structures deduced from NMR studies
are confirmed. For 3bCl and 6bCl, the ligand behaves as
[C,N,N0]-tridentate and three fused [6,5,5] ring systems
containing a five-membered endo metallacycle are formed.
For 3bCl, a chloro ligand completes the square-planar
coordination of the platinum atom, while for 6bCl an octa-
The presence of methyl or phenyl groups trans to the
labile ligand in the metallating substrate favours the biden-
tate [N,N0] coordination as well as the metallation process
leading to [C,N,N0] systems, which occurred in milder con-
ditions and with higher yields than when cis-[PtCl2(dmso)2]
was used as substrate. The smaller steric requirements of
methyl or phenyl versus chloro ligands allows for a E con-
formation of the imine ligand in the [N,N0] compounds and
this is the adequate arrangement for further metallation. In
addition the methyl and phenyl groups increase the nucle-
Fig. 2. Molecular structure of compound 3bCl.

1902
M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
Fig. 3. Molecular structure of compound 6bCl.
´
`
ophilicity of the platinum centre allowing for the synthesis
of [C,N,N0] cyclometallated platinum(IV) compounds via
oxidative addition of methyl iodide. Platinum(II) com-
pounds 3aCl and 3bCl containing a chloro ligand, although
unreactive towards methyl iodide, undergo oxidative addi-
tion of chlorine to produce the corresponding platinum(IV)
compounds.
Slight differences are observed in the behaviour of com-
pounds derived from ligands 1a or 1b. For instance, for
compounds 2bCl and 2bPh the presence of a phenyl substi-
tuent in an ortho position favours the Z isomer compared
to analogous compounds 2aCl and 2aPh. In addition, for-
mation of compound 3bCl is much slower than that of the
corresponding compound 3aCl indicating that the presence
of a phenyl substituent in an ortho position hinders the
process.
Cientıfics i Tecnics de la Universitat Rovira i Virgili
(Tarragona).
3.2. Preparation of the compounds
Compounds cis-[PtCl2(dmso)2] [14], cis-[PtPh2(SMe2)2]
[15], 4-C6H5C6H4CHNCH2CH2NMe2 (1a) and 2-C6H5-
C6H4CHNCH2CH2NMe2 (1b) [5] were prepared as
reported.
3.2.1. Synthetic procedure for the [N,N0] platinum(II)
compounds
Compound [PtCl2{4-C6H5C6H4CHNCH2CH2NMe2}]
(2aCl) was obtained from 100 mg (2.37 · 10ꢀ4 mol) of
cis-[PtCl2(dmso)2] and the equimolar amount (59.8 mg) of
1a after refluxing the mixture in methanol during 4 h. On
1
cooling, a white solid is formed. Yield: 90 mg (73%). H
3. Experimental
NMR (200 MHz, CDCl3): d = 2.69 [t, 2J(H–H) = 6.0,
Hb]; 3.14 [s, 3J(Pt–H) = 36.0, Mea]; 4.07 [t, 2J(H–
3
3.1. General
H) = 6.0, Hc]; {7.46–7.62 [m, 6H], 7.72 [d, J(H–H) = 8.0,
2H], 7.82 [t, 3J(H–H) = 8.0, 1H], aromatics}; 9.56 [s,
3J(Pt–H) = 59.0, Hd]. 195Pt NMR (54 MHz, CDCl3):
d = ꢀ2210.0 [s]. ESI-MS: 483 [M ꢀ Cl]. Anal. Found: C,
38.0; H, 3.9; N, 5.1. Calc. for C17H20Cl2N2Pt Æ H2O: C,
38.06; H, 4.13; N, 5.22%. After refluxing a dichlorometh-
NMR spectra were performed at the Unitat de RMN
1
d’Alt Camp de la Universitat de Barcelona. H, 13C and
195Pt NMR spectra were recorded by using Varian Gemini
200 (1H, 200 MHz), Bruker 250 (195Pt, 54 MHz), Mercury
400 (1H, 400 MHz; 13C, 100 MHz; 1H–1H NOESY;
1
ane solution during 10 h, isomer E is formed. H NMR
1
2
1H–13C gHSQC) and Varian 500 (1H and H–1H COSY,
(200 MHz, CDCl3): d = 2.68 [t, J(H–H) = 6.0, Hb]; 3.17
2
500 MHz) spectrometers, and referenced to SiMe4 (1H,
13C) and H2PtCl6 in D2O (195Pt). d values are given in ppm
and J values in Hz. Mass spectra (FAB or ESI) were per-
formed at the Servei d’Espectrometria de Masses de la Uni-
versitat de Barcelona using a VG-Quattro spectrometer.
Microanalyses were performed by the Servei de Recursos
[s, Mea]; 4.24 [t, J(H–H) = 6.0, Hc]; 8.76 [s, Hd].
Compound [PtCl2{2-C6H5C6H4CHNCH2CH2NMe2}]
(2bCl) was prepared following the same procedure than
for 2aCl from 1b. Yield: 90 mg (73%). 1H NMR
2
(200 MHz, CDCl3): d = 2.11 [t, J(H–H) = 6.0, Hb]; 2.91
[s, 3J(Pt–H) = 33.0, Mea]; 3.28 [t, 2J(H–H) = 6.0, Hc];

M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
1903
{7.30 [dd, 3J(H–H) = 8.0, 4J(H–H) = 2, 2H], 7.41–7.62 [m,
125.54, 126.73 [2C], 126.78 [2C], 128.64 [1C], 129.16 [2C],
129.26 [2C], 129.74, 130.48, 130.64, 138.26 [2C], 138.29
[2C], CAr–H}, {139.46, 141.29, 146.85, CAr}, 166.65 [Cd].
195Pt NMR (54 MHz, CDCl3): d = ꢀ3434.5 [s]. Anal.
Found: C, 58.0; H, 5.6; N, 4.4. Calc. for C29H30N2Pt: C,
57.89; H, 5.02; N, 4.66%.
3
7H], aromatics}; 9.64 [s, J(Pt–H) = 58.4, Hd]. 195Pt NMR
(54 MHz, CDCl3): d = ꢀ2299.0 [s]. ESI-MS: 483 [M ꢀ Cl].
Anal. Found: C, 38.2; H, 4.0; N, 5.1. Calc. for
C17H20Cl2N2Pt Æ H2O: C, 38.06; H, 4.13; N, 5.22%.
Compound [PtPh2{4-C6H5C6H4CHNCH2CH2NMe2}]
(2aPh) was obtained from 100 mg (2.11 · 10ꢀ4 mol) of
cis-[PtPh2(dmso)2] and the equimolar amount (53.3 mg)
of 1a after stirring the mixture in acetone at room temper-
ature during 30 min. The solvent was removed in a rotary
evaporator and the residue was treated with ether to yield
3.2.2. Synthetic procedure for the [C,N,N0] platinum(II)
compounds
Compound [PtCl{4-C6H5C6H3CHNCH2CH2NMe2}]
(3aCl) was prepared from 60 mg (1.16 · 10ꢀ4 mol) of
2aCl and the equimolar amount of Na(CH3COO) (9 mg)
after refluxing the mixture in methanol during 12 h. The
reaction mixture was cooled, filtered to remove unreacted
materials and concentrated to half volume. The obtained
crystals were recrystallised in dichloromethane-methanol
to yield red crystals. Yield: 25 mg (45%). 1H NMR
(400 MHz, CDCl3): d = 2.92 [s, 3J(H–Pt) = 14.0, Ha];
3.12 [t, 2J(H–H) = 6.0, Hb]; 4.04 [td, 2J(H–H) = 6.0,
4J(H–H) = 1.0, 3J(H–Pt) = 35.0, Hc]; {7.23 [dd, 3J(H–
1
a yellow solid. Yield: 90 mg (71%). H NMR (400 MHz,
3
CDCl3): d = 2.66 [s, J(H–Pt) = 21.2, Ha]; 2.78 [m, Hb];
2
3
4.19 [t, J(H–H) = 6.0, Hc]; {6.32 [t, J(H–H) = 7.2, 1H],
3
3
6.39 [t, J(H–H) = 7.2, 2H], 6.80 [t, J(H–H) = 7.2, 1H],
3
3
6.93 [t, J(H–H) = 7.2, 1H], 6.94 [d, J(H–H) = 8.0, 2H],
3
3
7.16 [d, J(H–H) = 8.0, 2H], 7.35 [d, J(H–H) = 8.0, 2H],
3
3
7.40 [t, J(H–H) = 7.4, 2H], 7.46 [d, J(H–H) = 7.6, 2H],
3
3
7.47 [t, J(H–H) = 7.6, 2H], 8.07 [d, J(H–H) = 8.0, 2H,
H2,6], aromatics}; 8.79 [s, 3J(Pt–H) = 46.4, Hd]. 13C
NMR (100 MHz, CDCl3): d = 50.16 [Ca], 65.49 [Cc],
66.40 [Cb], {121.03, 121.25, 125.65 [2C], 126.19 [2C],
126.73 [2C], 127.28 [2C], 127.95, 128.96 [2C], 130.40 [2C],
4
3
H) = 8.0, J(H–H) = 2, 1H, H3], 7.30 [d, J(H–H) = 8.0,
1H, H2], 7.33 [t, 3J(H–H) = 7.2, 1H, Rp4ara], 7.41 [t,
3J(H–H) = 7.2, 2H, Rm4 eta], 7.66 [dd, 3J(H–H) = 8.0,
4J(H–H) = 2, 2H, Ro4rtho], 7.99 [d, 4J(H–H) = 2.0, J(H–
Pt) = 44.0, 1H, H5], aromatics}; 8.24 [t, 4J(H–H) = 1.0,
3J(Pt–H) = 141.0, Hd]. 13C NMR (100 MHz, CDCl3):
d = 48.90 [Ca], 54.55 [Cc], 66.36 [Cb], {122.65, 127.65
[2C], 127.81, 128.20, 128.79 [2C], 132.99, CAr–H},
{141.50, 142.90, 144.55, 148.24, CAr}, 171.70 [2J(C–
Pt) = 112, Cd]. 195Pt NMR (54 MHz, CDCl3):
d = ꢀ3473.5 [s]. Anal. Found: C, 43.1; H, 4.4; N, 5.6. Calc.
for C17H19ClN2Pt: C, 42.37; H, 3.97; N, 5.81%.
138.33 [2C], 138.69 [2C],
CAr–H}, {131.56, 135.62,
140.78, 143.89, 147.91, CAr}, 164.93 [Cd]. 195Pt NMR
(54 MHz, CDCl3): d = ꢀ3436.0 [s]. After standing in solu-
tion during 48 h, isomer Z is formed: 1H NMR (400 MHz,
CDCl3): d = 2.64 [s, Ha]; 2.76 [m, Hb]; 4.07 [t, J(H–H) =
2
6.0, Hc]; {6.90 [t, 3J(H–H) = 7.0, 1H], 7.36 [t, 3J(H–
3
3
H) = 7.0, 2H], 7.58 [d, J(H–H) = 8.0, 2H], 7.64 [d, J(H–
H) = 8.0, 2H, H2,6], aromatics}; 8.42 [s, J(Pt–H) = 24.0,
3
Hd]. 195Pt NMR (54 MHz, CDCl3): d = ꢀ3398.4 [s]. Anal.
Found: C, 57.6; H, 5.5; N, 4.4. Calc. for C29H30N2Pt: C,
57.89; H, 5.02; N, 4.66%.
Compound [PtCl{2-C6H5C6H3CHNCH2CH2NMe2}]
(3bCl) was similarly obtained from 60 mg (1.16 ·
10ꢀ4 mol) of 2bCl and the equimolar amount of Na(CH3-
COO) (9 mg) after heating at 65 ꢁC the mixture in metha-
nol during 48 h. Yield: 20 mg (36%). 1H NMR
(400 MHz, CDCl3): d = 2.90 [s, 3J(H–Pt) = 14.2, Ha];
3.08 [t, 2J(H–H) = 6.0, Hb]; 4.03 [td, 2J(H–H) = 6.0,
4J(H–H) = 1.2, 3J(H–Pt) = 34.8, Hc]; {6.94 [dd, 3J(H–
Compound [PtPh2{2-C6H5C6H4CHNCH2CH2NMe2}]
(2bPh) was obtained as a light yellow solid following the
same procedure than for 2aPh from 1b. Yield: 90 mg
(71%). 1H NMR (200 MHz, CDCl3): d = 2.65 [s, 3J(H–
2
Pt) = 21.2, Ha]; 2.70 [m, Hb]; 4.00 [t, J(H–H) = 6.0, Hc];
3
3
{6.25 [t, J(H–H) = 7.2, 1H], 6.39 [t, J(H–H) = 7.2, 2H],
3
3
4
3
6.80 [d, J(H–H) = 7.4, 1H], 6.92 [t, J(H–H) = 7.6, 2H],
H) = 7.6, J(H–H) = 1.2, 1H, H3], 7.30 [t, J(H–H) = 7.6,
para
3
3
3
7.06 [t, J(H–H) = 7.6, 3H], 7.22 [d, J(H–H) = 7.0, 1H],
7.39–7.49 [m, 8H], 8.83 [d, 3J(H–H) = 7.6, 1H], aromatics};
8.51 [s, 3J(Pt–H) = 43.4, Hd]. 13C NMR (100 MHz,
CDCl3): d = 50.01 [Ca], 64.74 [Cc], 66.08 [Cb], {120.86,
121.17, 126.69 [2C], 126.99 [2C], 127.46 [2C], 127.96 [1C],
128.48 [2C], 128.64, 128.97, 129.93, 130.81, 138.22 [2C],
138.70 [2C], CAr–H}, {139.99, 140.90, 141.66, 148.35,
CAr}, 165.22 [Cd]. 195Pt NMR (54 MHz, CDCl3):
d = ꢀ3436.1 [s]. After standing in solution during 4 h, iso-
mer Z is formed: 1H NMR (400 MHz, CDCl3): d = 2.48 [s,
3J(H–Pt) = 16.8, Ha]; 2.53 [t, 2J(H–H) = 6.0, Hb]; 3.43
1H, H4 or R2 ], 7.33 [dd, J(H–H) = 8.0, 1.6, 2H, R2ortho],
7.38–7.42 [m, 3H, Rm2 eta þ H4 or Rp2ara], 7.75 [dd, 3J(H–
4
H) = 7.6, J(H–H) = 1, J(H–Pt) = 44.4, 1H, H5], aromat-
ics}; 8.35 [t, 4J(H–H) = 1.2, 3J(Pt–H) = 143.4, Hd]. 13C
NMR (100 MHz, CDCl3): d = 48.82 [Ca], 54.82 [Cc],
66.31 [Cb], {125.03, 127.64, 128.56 [2C], 129.55 [2C],
132.53, 133.79, CAr–H}, {141.20, 142.91, CAr}, 171.87
[Cd]. 195Pt NMR (54 MHz, CDCl3): d = ꢀ3476.0 [s]. Anal.
Found: C, 42.6; H, 3.6; N, 5.5. Calc. for C17H19ClN2Pt: C,
42.37; H, 3.97; N, 5.81%.
Compound [PtPh{4-C6H5C6H3CHNCH2CH2NMe2}]
(3aPh) was prepared from 60 mg (1.00 · 10ꢀ4 mol) of
2aPh after refluxing in toluene during 6 h. The solution
was filtered to remove a metallic residue. The solvent was
removed and the residue was treated with ether to produce
a red-brick solid. Yield: 40 mg (77%). 1H NMR (400 MHz,
2
3
[t, J(H–H) = 6.0, Hc]; {6.65 [t, J(H–H) = 7.2, 1H], 6.71
3
3
[t, J(H–H) = 7.6, 2H], 6.74 [t, J(H–H) = 7.2, 1H], 6.88
3
[t, J(H–H) = 7.6, 2H], 7.34–7.59 [m], aromatics}; 8.39 [s,
3J(Pt–H) = 27.2, Hd]. 13C NMR (100 MHz, CDCl3):
d = 49.20 [Ca], 54.02 [Cc], 64.51 [Cb], {121.31, 121.41,

1904
M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
3
2
CDCl3): d = 2.78 [s, J(H–Pt) = 20.4, Ha]; 3.19 [t, J(H–
[d, J(H–H) = 7.0, J(H–Pt) = 35.0, 2H, Phortho], aromatics};
8.43 [s, 3J(Pt–H) = 47.6, Hd]. 195Pt NMR (54 MHz, CDCl3):
d = ꢀ2344.8 [s]. FAB-MS: 538 [M ꢀ I], 523 [M ꢀ I ꢀ Me],
446 [M ꢀ I ꢀ Me ꢀ Ph]. Anal. Found: C, 43.8; H, 4.2; N,
4.6. Calc. for C24H27IN2Pt: C, 43.32; H, 4.09; N, 4.21%.
Compound [PtMePhI{2-C6H5C6H3CHNCH2CH2NMe2}]
(4bPh) was obtained from 3bPh using the method described
H) = 6.0, Hb]; 4.05 [t, J(H–H) = 6.0, Hc]; {6.94 [t, J(H–
2
3
para
H) = 7.2, 1H, Phpara or R4 ], 7.09 [t, J(H–H) = 7.6, 2H,
3
Phmeta or R4meta], 7.16 [dd, J(H–H) = 7.6; 1.6, 1H, H2 or
H3], 7.24 [t, J(H–H) = 7.2, 1H, Phpara or Rp4ara], 7.31 [dd,
3
3J(H–H) = 8.0, 4J(H–H) = 2.0, 1H, H2 or H3], 7.32 [t,
3J(H–H) = 7.2, 2H, Phmeta or Rm4 eta], 7.36 [d, 4J(H–
H) = 1.6, 1H, H5], 7.45 [dd, J(H–H) = 8.0; 1.6, 2H,
Ro4rtho], 7.59 [d, 3J(H–H) = 8.0, 3J(H–Pt) = 55.2, 2H,
Phortho], aromatics}; 8.48 [s, 3J(Pt–H) = 56.0, Hd]. 13C
NMR (100 MHz, CDCl3): d = 49.45 [Ca], 52.75 [2J(C–
Pt) = 29.0, Cc], 67.74 [Cb], {121.86 [C2 or C3], 122.01
[Phpara or R4para], 127.28 [J(C–Pt) = 70.6, 2C, Phmeta or
Rm4 eta], 127.37 [Phpara or R4para], 127.58 [2C, R4ortho], 128.65
[2C, Phmeta or R4meta], 128.78 [J(C–Pt) = 45.8, C2 or C3],
135.35 [2J(C–Pt) = 106.9, C5], 138.00 [2J(C–Pt) = 24.9,
2C, Phortho], CAr–H}, {141.94, 143.96, 144.39, 149.24,
153.42, CAr}, 169.51 [2J(C–Pt) = 95.9, Cd]. 195Pt NMR
(54 MHz, CDCl3): d = ꢀ3600.3 [s]. Anal. Found: C, 52.5;
H, 5.1; N, 5.4. Calc. for C23H24N2Pt: C, 52.76; H, 4.62;
N, 5.35%.
1
above for 4aPh. Yield: 25 mg (79%). H NMR (200 MHz,
2
3
CDCl3): d = 1.23 [s, J(Pt–H) = 68.4, Mea]; 2.68 [s, J(H–
Pt) = 14.0, Meb]; 3.16 [s, J(H–Pt) = 10.0, Mec]; {3.03 [m,
3
1H], 4.00 [d, J(H–H) = 11.0,0 1H], 4.15 [m, 1H], 4.28 [td,
0
J(H–H) = 11.0; 4.0, 1H], Hd;d ;e;e }; {6.99 [d, J(H–H) = 7.6,
3
1H]; 7.09–7.13 [m, 3H]; 7.23 [t, J(H–H) = 7.6, 1H]; 7.32
3
[d, J(H–H) = 8.0, 1H]; 7.40–7.47 [m, 5H]; 7.87 [d, J(H–
3
H) = 6.4, J(H–Pt) = 35.0, 2H], aromatics}; 8.40 [s, J(Pt–
H) = 48.8, Hd]. 195Pt NMR (54 MHz, CDCl3): d =
ꢀ2354.8 [s]. FAB-MS: 665 [M], 538 [M ꢀ I], 523
[M ꢀ I ꢀ Me], 446 [M ꢀ I ꢀ Me ꢀ Ph]. Anal. Found: C,
42.2; H, 4.1; N, 4.3. Calc. for C24H27IN2Pt Æ H2O: C, 42.17;
H, 4.28; N, 4.10%.
Compound [PtMe3I{2-C6H5C6H4CHNCH2CH2NMe2}]
(5aMe) was obtained as a white solid using an analogous
procedure to that described above from 30 mg
(6.3 · 10ꢀ5 mol) of 2aMe and a reaction time of 10 min.
Yield: 25 mg (64%). 1H NMR (500 MHz, CDCl3):
d = {0.85 [s, 2J(Pt–H) = 71.0], 1.05 [s, 3J(H–Pt) = 73.0],
Compound [PtPh{2-C6H5C6H3CHNCH2CH2NMe2}]
(3bPh) was obtained as a golden solid following the same
procedure from 2bPh. Yield: 35 mg (67%). 1H NMR
(400 MHz, CDCl3): d = 2.76 [s, 3J(H–Pt) = 20.4, Ha];
3.15 [t, J(H–H) = 6.0, Hb]; 3.96 [t, J(H–H) = 6.0, Hc];
{6.97 [t, 3J(H–H) = 7.2, 1H, Phpara or Rp2ara], 7.07 [dd,
3J(H–H) = 7.2; 2, 2H], 7.11 [t, J(H–H) = 7.4, 2H, Phmeta
2
2
2
3
1.24 [s, J(Pt–H) = 71.0], Mea, Meb, Mec}; {02.47 [s, J(H–
Pt) = 14.5], 3.23 [s, 3J(H–Pt) = 11.0], Med;d }; 2.70 [ddd,
J(H–H) = 13.0; 4.0; 3.0, 1H], 3.47 [td, J(H–H) = 13.0;
3.0, 1H], 3.93 [tt, J(H–H) = 13.0; 3.0, 1H], 4.09 [dt, J(H–
3
or Rm2 eta], 7.32–7.42 [m, 5H], 7.60 [d, J(H–H) = 7.0, J(H–
Pt) = 59.2, 2H, Phortho], aromatics}; 8.47 [s, 3J(Pt–
H) = 57.6, Hd]. 13C NMR (100 MHz, CDCl3): d = 49.41
[Ca], 53.14 [2J(C–Pt) = 28.5, Cc], 67.61 [Cb], {121.96 [Phpara
or R2para], 124.26, 127.33 [J(C–Pt) = 70.5, 2C, Phmeta or
Rm2 eta], 127.34, 128.37 [2C], 129.73 [2C], 132.22 [J(C–
Pt) = 76.8], 136.13 [2J(C–Pt) = 97.7], 138.02 [2J(C–
Pt) = 25.4, 2C, Phortho], CAr–H}, {141.77, 143.68, 144.10,
146.98, 154.87, CAr}, 169.36 [2J(C–Pt) = 94.5, Cd]. 195Pt
NMR (54 MHz, CDCl3): d = ꢀ3599.7 [s]. Anal. Found:
C, 52.0; H, 5.1; N, 5.1. Calc. for C23H24N2Pt: C, 52.76;
H, 4.62; N, 5.35%.
0
0
H) = 13.0; 4.0, 1H], He;e ;f;f }; {7.36 [t, J(H–H) = 7.0, 1H,
Rp4ara]; 7.44 [t, J(H–H) = 7.0, 2H]; 7.61 [d, J(H–H) = 7.0,
2H], 7.66 [d, J(H–H) = 8.0, 2H], 7.92 [d, J(H–H) = 8.0,
2H], aromatics}; 8.89 [s, 3J(Pt–H) = 32.0, Hg]. 195Pt
NMR (54 MHz, CDCl3): d = ꢀ2560.9 [s]. Anal. Found:
C, 36.9; H, 5.0; N, 4.2. Calc. for C20H29IN2Pt Æ 2H2O: C,
36.64; H, 5.07; N, 4.27%.
Compound [PtMe3I{2-C6H5C6H4CHNCH2CH2NMe2}]
(5bMe) was obtained as a white solid using the same proce-
dure than for 5aMe from 20 mg (4.2 · 10ꢀ5 mol) of 2bMe.
Yield: 15 mg (58%). 1H NMR (500 MHz, CDCl3):
d = {1.01 [s, 2J(Pt–H) = 71.2], 1.08 [s, 3J(H–Pt) = 72.8],
3.2.3. Synthetic procedure for the platinum(IV) compounds
Compound [PtMePhI{4-C6H5C6H3CHNCH2CH2NMe2}]
(4aPh) was obtained adding an excess of methyl iodide
(0.5 mL) to a solution of 25 mg of compound 3aPh in ace-
tone and stirring the mixture at room temperature. After
30 min, the solution colour changed from orange to yellow.
The solvent was removed and the residue was washed with
2
3
1.27 [s, J(Pt–H) = 72.0], Mea, Meb, Mec}; {02.49 [s, J(H–
Pt) = 14.4], 3.24 [s, 3J(H–Pt) = 10.8], Med;d }; 2.68 [ddd,
J(H–H) = 12.0; 6.0; 3.0, 1H], 3.42 [ddd, J(H–H) = 12.0;
9.0; 3.0, 1H], 3.74 [ddt, J(H–H) = 9.0; 6.0; 3.0, 1H], 4.10
0
0
[m, 1H], He;e ;f;f }; {7.42 [d, J(H–H) = 8.0, 1H]; 7.43–7.48
[m, 4H]; 7.52 [d, 2H], 7.54 [t, J(H–H) = 8.0, 1H], 8.20 [d,
1
3
ether. Yield: 25 mg (79%). H NMR (200 MHz, CDCl3):
J(H–H) = 8.0, 1H], aromatics}; 8.49 [s, J(Pt–H) = 33.2,
d = 1.23 [s, 2J(Pt–H) = 68.8, Mea]; 2.72 [s, 3J(H–
Hg]. 13C NMR (100 MHz, CDCl3): d = {ꢀ5.56 [1J(C–
Pt) = 681.5], ꢀ4.90 [1J(C–Pt) = 659.4], 9.59 [1J(C–
Pt) = 735.6], Mea, Meb, Mec}; {46.87, 54.50, Med, Mee};
{62.95, 63.21, Cf, Cg}; {126.96, 128.34, 128.82 [2C],
129.23, 129.97 [2C], 130.63, 131.38, CAr–H}, {131.86,
139.29, 141.87, CAr}, 170.45 [Cd]. 195Pt NMR (54 MHz,
CDCl3): d = ꢀ2566.3 [s]. Anal. Found: C, 38.3; H, 4.7;
N, 4.4. Calc. for C20H29IN2Pt: C, 38.78; H, 4.72; N, 4.52%.
Pt) = 15.2, Meb]; 3.17 [s, J(H–Pt) = 11.2, Mec]; {3.08 [dt,
3
J(H–H) = 12.0; 4.0, 1H], 4.10 [d, J(H–H) = 12.0, 1H], 4.25
[dd, J(H–H) = 12.0; 4.0, 1H], 4.37 [td, J(H–H) = 12.0;
0
0
4.0, 1H], Hd;d ;e;e }; {7.08 [d, J(H–H) = 7.2, 1H]; 7.13 [t,
3J(H–H) = 8.0, 2H]; 7.32 [t, J(H–H) = 8.0, 2H]; 7.39 [t,
3
3J(H–H) = 7.2; 2H]; 7.44 [d, J(H–H) = 8.0, 1H]; 7.57 [dd,
3J(H–H) = 7.2; 1.2 2H]; 7.61 [d, J(H–H) = 1.2, 1H], 7.88

M. Crespo et al. / Journal of Organometallic Chemistry 691 (2006) 1897–1906
1905
Table 2
Compound [PtCl3{4-C6H5C6H3CHNCH2CH2NMe2}]
Crystallographic and refinement data for compounds 3bCl and 6bCl
(6aCl) was obtained treating a solution of 10 mg of com-
pound 3aCl in acetonitrile (10 mL) with 10 mL of acetoni-
trile saturated with chlorine. The colour of the solution
faded readily and the mixture was stirred during 10 min.
The solvent was removed to produce a light yellow solid.
Yield: 8 mg (70%). 1H NMR (200 MHz, CDCl3):
d = 2.94 [s, 3H, Mea]; 3.06 [s, 3H, Mea]; {3.20 [m], 3.76
[m], 4.09 [m], 5.27 [m], Hb, Hc}; {7.39–7.51 [m, 4H],
Compound 3bCl
Compound 6bCl
Formula
Formula weight
Temperature (K)
C17H19ClN2Pt
481.88
293(2)
C17H19Cl3N2Pt
552.78
293(2)
˚
Wavelength (A)
0.71073
0.71073
Crystal system, space group Orthorhombic, Pcab Monoclinic, P21/c
˚
a (A)
11.102(5)
11.224(3)
25.986(9)
90
90
90
3238 (2); 8
1.977
8.826
7.042(5)
12.916(6)
20.119(9)
90
101.56(3)
90
1792.8(17); 4
2.048
8.273
˚
b (A)
3
˚
c (A)
7.61–7.69 [m, 3H], 7.80 [s, 1H], aromatics}; 8.39 [s, J(Pt–
H) = 100.8, Hd]. ESI-MS: 516 [M ꢀ Cl], 483 [M ꢀ 2Cl].
Anal. Found: C, 36.6; H, 3.8; N, 5.3. Calc. for
C17H19Cl3N2Pt: C, 36.93; H, 3.46; N, 5.07%.
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A ); Z
dcalcd (Mg/m3)
Compound [PtCl3{2-C6H5C6H3CHNCH2CH2NMe2}]
(6bCl) was crystallised from a equimolar mixture of cis-
[PtCl2(dmso)2] and 1b in dichloromethane. Alternatively,
Absolute coefficient (mmꢀ1
F(000)
)
1840
1056
Number of reflections
collected/unique (Rint
Data/restraints/parameters
Goodness-of-fit on F2
R1[I > 2r(I)]
3695/3695
(0.0414)
3695/0/182
1.192
18,706/5421
(0.0428)
5421/2/208
1.113
1
compound 6bCl was prepared as described for 6aCl. H
)
NMR (200 MHz, CDCl3): d = 2.92 [s, 3H, Mea]; 3.01 [s,
3H, Mea]; {3.26 [m, 1H], 3.67 [m, 1H], 3.97 [m, 1H], 5.18
[m, 1H], Hb, Hc}; {7.31 [d, J(H–H) = 7.6, 1H], 7.42–7.52
[m, 6H], 7.60 [dd, J(H–H) = 8; 1, 1H], aromatics}; 8.21
0.0530
0.0429
wR2 (all data)
Peak and hole (e A
0.1252
0.630 and ꢀ0.625
0.1021
0.620 and ꢀ0.843
ꢀ3
˚
)
3
[s, J(Pt–H) = 102.8, Hd]. ESI-MS: 483 [M ꢀ 2Cl]. Anal.
Found: C, 36.1; H, 4.5; N, 5.4. Calc. for C17H19Cl3N2Pt:
C, 36.93; H, 3.46; N, 5.07%.
thesis and refined with an overall isotropic temperature fac-
tor and 1H was computed and refined, using a riding
model, with an isotropic factor equal to 1.2 times the equiv-
alent temperature factor of the atom to which they are
linked. For 6bCl, all hydrogen atoms were computed and
refined. Further details are given in Table 2.
3.3. X-ray structure analysis
3.3.1. Data collection
Crystals of 3bCl and 6bCl were obtained from slow
evaporation of acetone and dichloromethane solutions,
respectively. Prismatic crystals were selected and mounted
on an MAR345 diffractometer with an image plate detec-
tor. Unit cell parameters were determined from 288
(3bCl) or 148 (6bCl) reflections (3ꢁ < h < 31ꢁ) and refined
by least-squares method. Intensities were collected with
graphite monochromatised Mo Ka radiation. For 3bCl,
3695 reflections were measured in the range 3.49ꢁ < h <
31.92ꢁ and 3020 were assumed as observed applying the
condition I > 2r(I). For 6bCl, 18,706 reflections were mea-
sured in the range 3.48ꢁ < h < 31.82ꢁ, 5421 were non-equiv-
alent by symmetry and 4077 were assumed as observed
applying the condition I > 2r(I). Lorentz polarisation and
absorption corrections were made. Further details are
given in Table 2.
4. Supplementary material
The crystallographic data of compounds 3bCl and 6bCl
have been deposited with the Cambridge Crystallographic
Data Centre, CCDC 291025 and 291026, respectively.
Acknowledgements
This work was supported by the Ministerio de Ciencia y
´
Tecnologıa (Project: BQU2003-00906/50% FEDER) and
by the Comissionat per a Universitats i Recerca (Project:
2001SGR-00054).
References
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