N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic activity of the related bidentate chelate platinum complexes in hydroformylation

Article abstract of DOI:10.1016/j.jorganchem.2012.07.031

The microwave-assisted double Kabachnik-Fields (phospha-Mannich) reaction of benzylamine and arylamines, two equivalents of paraformaldehyde and the P(O)H reagent, such as dialkyl phosphites, ethyl phenyl-H-phosphinate and diphenylphosphine oxide gave the bis(P(O)CH₂)amine derivatives in good yields. The bis(diphenylphosphinoxido) derivatives were converted to the corresponding ring platinum complexes after deoxygenation whose catalytic activity was tested in the hydroformylation of styrene. Crystal structure analysis of one of the complexes reveals interesting correlations between complex structure and solvent inclusion.

Full text of DOI:10.1016/j.jorganchem.2012.07.031

Journal of Organometallic Chemistry 717 (2012) 75e82
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Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
N-Benzyl and N-aryl bis(phospha-Mannich adducts): Synthesis and catalytic
activity of the related bidentate chelate platinum complexes in hydroformylation
Erika Bálint a, Eszter Fazekas a, Péter Pongrácz b, László Kollár b, László Drahos c, Tamás Holczbauer c,
,
Mátyás Czugler c, György Keglevich a
*
a Department of Organic Chemistry and Technology, Budapest University of Technology and Economics, 1521 Budapest, Hungary
b Department of Inorganic Chemistry, University of Pécs and Szentágothai Research Center, 7624 Pécs, Hungary
c Department of Structural Chemistry, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1525 Budapest, Hungary
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 21 May 2012
Accepted 18 July 2012
The microwave-assisted double KabachnikeFields (phospha-Mannich) reaction of benzylamine and
arylamines, two equivalents of paraformaldehyde and the pP(O)H reagent, such as dialkyl phosphites,
ethyl phenyl-H-phosphinate and diphenylphosphine oxide gave the bis(pP(O)CH2)amine derivatives in
good yields. The bis(diphenylphosphinoxido) derivatives were converted to the corresponding ring
platinum complexes after deoxygenation whose catalytic activity was tested in the hydroformylation of
styrene. Crystal structure analysis of one of the complexes reveals interesting correlations between
complex structure and solvent inclusion.
Keywords:
KabachnikeFields reaction
N,N-Bis(pP(O)-methyl)amine derivatives
Bidentate chelate platinum complex
Hydroformylation
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
Bis(phosphonomethyl)amines may be interesting building
blocks
in
synthetic
organic
chemistry.
The
double
a
-Aminophosphonates and related derivatives are evergreen
targets in biochemistry due to their versatile bioactivity [1e3]. The
most common approach to -aminophosphonates is the conden-
KabachnikeFields condensation made available lipophilic deriva-
tives [15]. The use of phosphorous acid as the P-reactant led to
bis(phosphonic acids) [16,17]. Bis(phosphinoxido)derivatives were
synthesized via a surprising methylene insertion reaction into
a PeN bond followed by oxidation [18].
We have elaborated a MW-assisted solvent-free method for the
synthesis of N-alkyl bis(pP(O)CH2)amino derivatives [19,20]. The
stereostructure of a related N-cyclohexyl ring platinum complex
was studied in detail [20]. In this paper, new N-benzyl and N-aryl
bis(pP(O)CH2)amino species and the bidentate chelate platinum
complexes of the corresponding bis(phosphino) derivatives are
discussed. The latter ring platinum complexes were tested as
catalysts in the hydroformylation of styrene.
a
sation of an amine, an aldehyde or ketone and a dialkyl phosphite
that is called the KabachnikeFields (phospha-Mannich) reaction
[4e6].
A number of catalytic versions of the KabachnikeFields reaction
were developed. However, it was found that, especially under
solvent-free conditions, there is no need for catalysts [7,8]. The
efficiency could be further increased by the microwave (MW)
technique [9e11].
A novel preparation of
substitution of -hydroxyphosphonates by amines. This reaction
a-aminophosphonates involves the
a
takes place with an unexpected ease as a consequence of a neigh-
bouring group effect [12].
2. Results and discussion
The mechanism of the KabachnikeFields reaction has been the
subject of a lot of studies [6]. One of the authors of this article with
co-workers could prove the intermediacy of the imine intermediate
in a few cases studied utilizing the method of in situ Fourier
Transform Infrared spectroscopy [13,14].
2.1. Synthesis of new bis(phospha-Mannich adducts)
To extend the scope of the efficient synthesis of bis(pP(O)CH2)
amino derivatives, first benzylamine and 4-methoxyaniline were
reacted with two equivalents of paraformaldehyde and the pP(O)H
species, such as dialkyl phosphites and ethyl phenyl-H-phosphinate
on MW irradiation at 100 ꢀC for 1 h without using any solvent to
afford the corresponding products 1aee and 2aed, respectively, in
* Corresponding author. Tel.: þ36 1 4631111/5883; fax: þ36 1 4633648.
E-mail address: gkeglevich@mail.bme.hu (G. Keglevich).
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.07.031

76
E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
O
P
OR
Z
OR
MW
RO
Z
CH2
CH2
O
H
100 °C, 1 h
P
Y
NH2
Y
N
+ 2 (HCHO)n + 2
no solvent
P
Z
O
2
a
b
c
d
e
1
3
2
3
2
Me Et Bu Bn Et
OMe OEt OBu OBn Ph
R
Z
1
1
4
4
Y
CH2
MeO
Scheme 1.
O
MW
Ph
Ph
O
CH2
PPh2
100 °C, 1.5 h
P
Y
N
Y
NH2
+ 2 (HCHO)n + 2
acetonitrile
H
CH2
PPh2
O
3
3
2
3
2
3
2
3
2
1
1
1
1
4
4
4
4
Y =
CH2 (a), MeO
(b),
(c), Me
(d)
Scheme 2.
81e98% yields after flash column chromatography (Scheme 1). Due
to the stereogenic center in ethyl phenyl-H-phosphinate, the
related bis(phospha-Mannich adduct) 1e was obtained as a 51:49
mixture of two stereoisomers.
In the next round, benzylamine and arylamines were reacted
with two equivalents of paraformaldehyde and diphenylphosphine
oxide as above with the only difference that acetonitrile was used
as the solvent due to the heterogeneity of the reaction mixture.
After an irradiation of 1.5 h, chromatography afforded the products
3aed in 55e95% yields (Scheme 2).
The bis(phosphine oxides) 3aed were subjected to double
deoxygenation and the diphosphines 5aed so obtained
were reacted with dichlorodibenzonitrile platinum to furnish
cis chelate platinum complexes 6aed in yields of 45e60%
(Scheme 3).
All compounds prepared (1aee, 2aed, 3aed and 6aed)
were characterized by 31P, 13C and 1H NMR, as well as mass spec-
tral data.
In the reaction of aniline, paraformaldehyde and diphenyl-
phosphine oxide, a by-product with an elemental composition of
C39H36N2O2P2 ([M þ H]þ ¼ 627.2325 (found) and 627.2330
(calculated)) and with a dP of 27.7 (CDCl3) was also identified in
a quantity of ca. 15%. Its structure was substantiated as bis(ami-
nophosphine oxide) 4.
O
Ph
H2C
Ph
N CH2
N CH2
PPh2
PPh2
O
4
Fig. 1. An atomic displacement (ORTEP-style) plot of the asymmetric unit in the 6b
crystal.
Ph
80 °C, 3 days
PhSiH3, N2
25 °C, 1 day
Ph
..
CH2
PPh2
..
CH2
P
Pt(PhCN)2Cl2, N2
3
Y
N
Y
N
PtCl2
Ph
benzene
benzene
CH2
PPh2
CH2
P
Ph
6
5
Y = as above
Scheme 3.

E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
77
molecules in the asymmetric unit of the orthorhombic Pbca space
group. One of the 6b molecules as well as one of the solvent
molecules shows clear signs of conformational disorder, apparent
in the rotation of some of the phenyl rings in complex 6b. The
disorder was modelled by 2/3:1/3 major:minor atomic positions for
these appropriate molecular entities. An overlay of the two inde-
pendent 6b molecules of the asymmetric unit reveals close simi-
larity in the shape and dimensions of the central 6-membered
heterorings (see Fig. 2), but also accentuates differently twisted
phenyl rings, hence giving a good reason for the appearance of
more than one molecule in the asymmetric unit. The role of the
included DCM solvent appears to be unequal, too. The ordered
solvent molecule provides three interesting short contacts to the
neighbouring ordered host 6b molecules in the crystal. One of these
is a phenyl CeH/Cl contact at 2.91 Å, (CeH/Cl 135ꢀ) (where C/Cl
3.644(9) Å) another Cl/C(phenyl) short distance at 3.438(9) Å
(CeCl/C 137.2(5)ꢀ) is just shorter than the van der Waals’ radii
sum. These two probably productive interactions are of both well-
known types of CeH/X type hydrogen bridges and dispersive
interactions, respectively. A bit more unusual is the 2.87 Å DCM
CeH/Pt (CeH/Pt1 150ꢀ) distance as the third interaction possi-
bility. However, such contacts fall entirely in the range of the so-
called anagostic contact types [21]. As shown by inseminating
analyses by Braga and Desiraju [22] as well as a more recent one
[23] these short contact types may rather be termed as somewhat
rare CeH/M type H-bridges. Apparently as even a study from 2006
[23] listed only two of the Pt-type metal acceptors we deemed
appropriate to extend this study for more recent examples of
square planar d8 e metal examples with more Pt-centres found
since then. Thus a Cambridge Structural Database [24] study was
additionally performed. These then also include our recent struc-
ture studies of complex 6b of this paper. Fig. 3 shows the
Fig. 2. Overlay of the two independent 6b molecules through their least-square fit of
the respective six-membered heterocycles (for the sake of clarity only major disorder
sites are used and H-atoms omitted from the drawing).
Crystal structure of ring platinum complex 5b was determined
by single crystal X-ray analysis. The resulting structure (Fig. 1)
corroborates molecular structure of ring Pt-complex 6b.
2.2. Intermolecular relations of molecular structure 6b and the
solvent inclusion
At the onset of the crystal structure analysis it was unknown
that the crystals contain solvent from the crystal growth. The
crystals of complex 6b were grown from dichloromethane (DCM)
and crystallized with two 6b molecules as well as two solvent
Fig. 3. Correlation of the H/M (M ¼ Ni, Pd, Pt) distances and CeH/M (M ¼ Ni, Pd, Pt) angles in 6b (blue circle) and in recent literature data from using the CSD database [32]. The
database hits are mostly from Pt, Pd and Ni are represented with 3 and 2 entries. (For interpretation of the references to colour in this figure legend, the reader is referred to the web
version of this article.)

78
E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
Table 1
correlation of the H/M (M ¼ Ni, Pd and Pt) contact distances
plotted against the respective CeH/M angles, suggesting accept-
able correlations of these parameters and corresponding to H-
bridge-like interactions. 6b Performs close to the correlations line
and as expected on its H/Pt distance.
Hydroformylation of styrene in the presence of in situ catalysts formed from
PtCl2(PNP) complexes (6a, 6b, 6d, 6e) and tin(II) chloride.a
Entry Complex Temp. (ꢀC) Pt/SnCl2 R. time (h) Conv. (%) Rcb (%) Rbrc (%)
1
2
3
4
5
6
7
8
6a
6a
6a
6a
6a
6b
6b
6b
6b
6d
6d
6d
6d
6e
6e
6e
6e
6e
6e
40
60
60
100
100
40
1/2
1/1
1/2
1/1
1/2
1/1
1/2
1/1
1/2
1/1
1/2
1/1
1/2
1/1
1/1
1/1
1/1
1/2
1/5
20
5
5
1
1
20
20
1
63
87
85
65
73
92
73
89
93
33
71
36
96
63
>99.8
85
>99.8
94
87
79
76
76
56
65
80
81
67
70
79
80
65
73
78
78
77
64
67
66
80
77
76
68
67
79
79
68
67
77
78
69
70
79
74
76
63
66
67
It is presumably these three close contacts that mutually help
stabilizing both one of the 6b molecules as well as the of the DCM
solvent in the crystal structure. The second disordered DCM
molecule has contacts to only the other 6b molecule, so these two
entities appear to be fairly isolated in that there are no cross-
contacts at all. There is, however, no contact to the Pt and the
three CeH/Cl contacts are split such that the minor disorder
position is also involved (i.e. there are only two interactions per
DCM molecules of the second types). It is also to be noted that the
phenyl rings maintaining the two C(phenyl)eH/Cl contacts give rise
to the two ordered phenyl rings while the other two rings, appar-
ently lacking such contacts, are disordered thus may provide yet
another hint on the inter-dependence of disorder and productive
interactions. These data call for attention to the role of the corre-
sponding solvent in complexes of this type and may also provide
some insight into the fairly intricate relations that may exist in such
systems not only in the solid phase.
40
100
100
40
9
1
10
11
12
13
14
15
16
17
18
19
20
20
1
40
100
100
40
60
60
100
100
100
1
20
20
5
3
1.5
1.5
A: 2-phenylpropanal, B: 3-phenylpropanal, C: ethylbenzene.
a
Reaction conditions: Pt/styrene ¼ 1/100, p(CO)]p(H2) ¼ 40 bar, 0.005 mmol
catalyst, 0.5 mmol of substrate, solvent: 5 mL of toluene.
b
Chemoselectivity towards aldehydes (A, B). [(moles of A þ moles of B)/(moles of
2.3. Catalytic activity of the PtCl2(h1 1-(P,P)ePNP) complexes (6a,
,h
6b, 6d and 6e) in the hydroformylation of styrene
A þ moles of B þ moles of C) ꢁ 100].
c
Regioselectivity towards branched aldehyde (A). [moles of A/(moles of
A þ moles of B) ꢁ 100].
The earlier experiences of Kollár and Keglevich showed that the
wide variety of platinumephosphine complexes may reveal inter-
esting catalytic activity in the hydroformylation of styrene deriva-
tives [25,26]. For this, the ring Pt complexes cis-[(benzyl-
bis(diphenylphosphinomethyl)amine)-dichloro-platinum(II)] 6a
14, respectively). Although the presence of various amines (in
excess to platinum) reduced substantially the catalytic activity [27],
in case of these PNP ligands with a non-coordinating N-atom,
highly active catalysts were obtained with an SnCl2/Pt ratio being as
low as 1/1. The catalytic activities of the in situ catalysts, containing
the tin(II) chloride additive in various amounts, are similar. A slight
decrease of activity with increasing amount of tin(II) chloride was
observed in the case of 6a, 6b and 6e. (Table 1/entries 2, 3 and 6, 7
and 17e19, respectively). An opposite trend for the change in the
activity was observed with 6d.
The formation of the aldehyde regioisomers (A and B) was
preferred in all cases that is numberized by chemoselectivities of
70e79%, 67e81%, 65e80% and 64e78% using complexes 6a, 6b, 6d
and 6e as catalyst precursors, respectively. The known tendency of
increasing chemoselectivity towards aldehydes with decreasing
reaction temperature was observed. For example, in the presence of
6a as the catalytic precursor, slightly decreasing chemoselectivities
of 79, 76 and 56% were obtained at 40, 60, and 100 ꢀC, respectively
(Table 1/entries 1, 2 and 4). A similar influence of the temperature
on the chemoselectivity was observed also with 6b, 6d and 6e as
the catalyst precursors (Table 1/entries 6, 8 and 10,12 and 14,16,17).
It is worth noting, that the SnCl2/Pt ratio has practically no influ-
ence on the chemoselectivity using 6a (Table 1/entries 2 and 3), 6b
(Table 1/entries 6 and 7), 6d (Table 1/entries 10 and 11) or 6e
(Table 1/entries 17e19).
As regards the regioselectivity, the branched aldehyde (A) pre-
dominated over the linear one (B) in all cases. Regarding platinum-
catalyzed hydroformylations, surprisingly high regioselectivities
towards branched aldehyde (A) were obtained. In our previous
studies we have demonstrated that the application of some mon-
odentate P-heterocycles, such as phosphole, phospholene or
phospholane ligands resulted in similar “branched selectivities” in
the platinum-catalyzed hydroformylation of styrene [28]. It should
be added that even higher preference for the branched aldehyde (2-
phenylpropanal) is characteristic for the rhodium-catalyzed
hydroformylation of styrene [29]. With all catalytic precursors,
the dependence of the regioselectivities on the reaction
and
cis-[(aryl-bis(diphenylphosphinomethyl)amine)-dichloro-
platinum(II)] 6b,d along with the earlier reported N-cyclohexyl
derivative (6e) [20] were tested as catalyst precursors in the
hydroformylation of styrene.
Ph
Ph
CH2
P
N
PtCl2
Ph
CH2
P
Ph
6e
[20]
The platinum-containing in situ catalysts formed either from 6a,
6b, 6d or 6e and tin(II) chloride under standard ‘oxo-conditions’
(p(CO)]p(H2) ¼ 40 bar, reaction temperature varied from 40 ꢀC to
100 ꢀC) were used. As generally observed, in addition to the
branched and linear formyl regioisomers (2-phenylpropanal (A)
and 3-phenylpropanal (B), respectively), the hydrogenation by-
product ethylbenzene (C) was also formed (Scheme 4).
The catalytic activity of the above system is comparable to that
of the best platinumediphosphineetin(II) chloride catalysts. The
use of 1% platinum precursor related to the substrate proved to be
an active catalyst in the temperature range of 40e100 ꢀC (Table 1).
The in situ catalysts, formed from complexes 6a, 6b, 6d and 6e, have
shown remarkable activity already at 40 ꢀC (entries 1, 6/7, 10/11 and
CO/H2
PhCH CH2
PhCH(CHO)CH3 + PhCH2CH2CHO + PhCH2CH3
B
C
A
Scheme 4. General scheme for the hydroformylation of styrene.

E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
79
temperature has shown the same tendency. That is, decrease of the
branched selectivity with increasing temperature was observed.
For example, regioselectivities of 79, 74 and 63% were obtained
using precursor 6e at 40, 60 and 100 ꢀC, respectively, while the
other conditions were kept constant (Table 1/entries 14, 15 and 17).
A similar decrease of the branched selectivity with increasing
temperature was observed also with catalytic precursor 6a, 6b and
6d (Table 1/entries 2, 4 and 6, 8 and 10, 12, respectively). The
influence of SnCl2/Pt ratio on the activity of platinum complexes
was also studied. It has to be mentioned that in most examples
published up to now [30], the SnCl2/Pt ratio was kept either on 2 or
5. Its role is to form the trichlorostannato ligand, a facile leaving
group from the Pt(PP)R(SnCl3) complex. It has been proved that the
dissociation of the SnClꢂ3 ligand provides a vacant coordination site
in an ionic complex, while the trichlorostannate ion serves as
a counterion [31]. The vacant coordination site enables the coor-
dination of carbon monoxide and therefore leads to catalytically
active species.
In our case, the investigation of the effect of tin(II) chloride
cocatalyst on the catalytic activity is of special importance since the
non-coordinated nitrogen atom of the PNP ligands may act as
a Lewis base coordinating to SnCl2, or as an HCl/HSnCl3 acceptor.
The reactions should lead to decreased catalytic activities at low
SnCl2/Pt ratios because the tin(II) chloride is attached to the central
tertiary N atom of the ligand, and as a consequence of that, there
would be no chance to form trichlorostannato ligand of key
importance in providing active cationic species (vide supra).
However, we have found that all precursors (6a, 6b, 6d and 6e) are
active even at low SnCl2/Pt ratios (w1). This behaviour is ratio-
nalized on the basis of the simplified mechanistic scheme below
(Scheme 5). The close proximity of the basic, non-coordinating
tertiary N acts as an HCl acceptor formed upon the hydro-
genolysis of the PteCl bond. After protonation, the ligand behaves
as
a cis-coordinating bidentate diphosphine ligand with an
ammonium moiety throughout the reaction. In this way, instead of
coordinating the tin(II) halide cocatalyst and leading to catalysts of
low activities, the nitrogen atom will be protonated by the HCl
liberated to form the platinum-hydrido species (8), the ‘starting’
complex of the catalytic cycle. According to a generally accepted
mechanism of platinum-catalyzed hydroformylation, the coordi-
nation of the substrate provides the five-coordinated alkene
complex (9). The insertion of alkene into the PteH bond results in
the formation of the alkyl complex (10). The insertion of carbon
monoxide and the immediate coordination of the ‘second’ carbon
monoxide results in the platinum-acyl-carbonyl complex (11)
which undergoes hydrogenolysis in the product forming step.
To check whether tin(II) chloride insertion into PteCl bond takes
place even at low SnCl2/Pt ratio, in situ NMR experiments were
carried out using tin(II) chloride in equimolar amount to platinum.
The formation of the PtCl(SnCl3)(PNP) complexes (7) of key cata-
lytic importance was unequivocally proved by 31P NMR spectros-
copy. The chemical shift of phosphorus atoms trans to tin has
a characteristic downfield shift related to that of the phosphorus
atoms trans to chloride [32]. That is, approximately 5 ppm down-
field shift was observed on the phosphorus atoms trans to the tri-
chlorostannato ligand in 7a, 7b, 7d and 7e. In the same time,
1
a typical JPt,P coupling of about 2700 Hz can be observed on the
phosphorus trans to tin reflecting to the presence of a tri-
chlorostannato ligand with stronger trans influence. (31P NMR
(CDCl3) 7a:
d
: ꢂ8.07 (1JP(A),Pt ¼ 3285), ꢂ2.04 (1JP(B),Pt ¼ 2694),
2JP,P ¼ 16.0; 7b:
d
: ꢂ6.34 (1JP(A),Pt ¼ 3262), ꢂ0.54 (1JP(B),Pt ¼ 2728),
2JP,P ¼ 16; 7d:
d
: ꢂ6.09 (1JP(A),Pt ¼ 3255), ꢂ0.19 (1JP(B),Pt ¼ 2685),
P
Cl
Cl
P
P
Cl
SnCl2
R
N
Pt
R
N
Pt
P
6
SnCl3
7
H2, CO
H2C CHR'
R'CH(CH3)CHO
H2
Cl
P
P
H
R
NH
Pt
SnCl3
CO
8
CH3
O
H2C CHR'
Cl
Cl
P
P
CH R'
P
H
R
NH
Pt
R
NH
Pt
SnCl3
SnCl3
CO
11
P
CO
9
CH3
Cl
P
P
CH R'
R
NH
Pt
CO
SnCl3
CO
10
Scheme 5. Simplified mechanism of the platinum-catalyzed hydroformylation of an alkene in the presence of catalytic precursor 6 containing PNP ligands (for clarity reasons, the
formation of the branched regioisomer is depicted only).

80
E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
3
2JP,P ¼ 16; 7e:
d
: ꢂ8.80 (1JP(A),Pt ¼ 3287), ꢂ3.23 (1JP(B),Pt ¼ 2725),
reversed; 1H NMR (CDCl3)
d
: 0.94 (t, JHH ¼ 7.4, 12H, CH2CH3),
2JP(A),P(B) ¼ 16.5).
1.34e1.46 (m, 8H, CH2CH3), 1.60e1.69 (m, 8H, OCH2CH2), 3.17 (d,
2JPH ¼ 9.1, 4H, CH2P), 3.97e4.10 (m, 10H, OCH2, CH2N (overlapped)),
3. Conclusion
7.26e7.40 (m, 5H, ArH); [M þ H]þ
¼ 520.2963, C25H48NO6P2
found
requires 520.2957.
In conclusion, a series of new N-benzyl and N-aryl bis(phospha-
Mannich adducts) were prepared and characterized. After double
deoxygenation, the bis(diphenylphosphinoxido) derivatives were
converted to the corresponding 6-ring platinum complexes.
The crystal structure determination of the N-(4-
methoxyphenyl) complex from a slightly decayed solvent inclu-
sion crystal suggests a direct correlation between the number and
type of productive interactions of the solvent guest from/to the
complex host molecules and the appearance of motility as
expressed by structural disorder.
4.2.4. N,N-Bis(dibenzyloxyphosphonylmethyl)benzylamine (1d)
Yield: 91% (1.0 g); 31P NMR (CDCl3) : 26.4; 13C NMR (CDCl3)
d d:
50.1 (dd, 1JCP ¼ 156.3, 3JCP ¼ 7.5, CH2P), 61.1 (t, 3JCP ¼ 7.8, CH2N), 67.6
a
b
0
0
(m, OCH2), 128.0 (C3) , 128.2 (C3 ) , 128.50 (C4), 128.55 (C4 ), 128.6
a
b
3
3
0
0
(C2) , 128.7 (C2 ) , 136.46 (d, JCP ¼ 3.1), 136.50 (d, JCP ¼ 3.2) (C1 ),
137.9 (C1), a,bmay be reversed; 1H NMR (CDCl3)
d
: 3.20 (d, 2JHP ¼ 8.8,
4H, CH2P), 3.95 (s, 2H, CH2N), 4.91e5.03 (m, 8H, OCH2), 7.19e7.37
(m, ArH); [M þ H]þ
¼ 656.2311, a C37H40NO6P2 requires
found
656.2331.
The in situ formed platinumePNPetin(II)chloride systems
proved to be active catalysts in the hydroformylation of styrene
providing the branched aldehyde in high regioselectivities.
4.2.5. N,N-Bis(dimethoxyphosphonylmethyl)-4-methoxyaniline
(2a)
Yield: 85% (0.53 g); 31P NMR (CDCl3) : 26.3; 13C NMR (CDCl3)
d d:
4. Experimental
47.4 (d, 1JCP ¼ 157.4, CH2P), 52.8 (t, 1JCP ¼ 3.4 POCH3), 55.8 (CH3O),
114.7 (C3)*, 116.4 (C2)*, 142.2 (C1), 153.2 (C4), *may be reversed; 1H
4.1. General (instruments)
NMR (CDCl3)
d
: 3.66 (d, 3JPH ¼ 10.5, 12H, POCH3), 3.72 (s, 3H, CH3O),
2
3.87 (d, JPH ¼ 6.0, 4H, CH2P), 6.78e6.81 and 6.87e6.90 (m, 4H,
The 31P, 13C, 1H NMR spectra were taken on a Bruker AV-300 or
DRX-500 spectrometer operating at 121.5, 75.5 and 300 or 202.4,
125.7 and 500 MHz, respectively. The couplings are given in Hz.
Mass spectrometric measurements were performed using a Q-TOF
Premier mass spectrometer (Waters Corporation, 34 Maple St,
Milford, MA, USA) in positive electrospray mode.
ArH); [M þ H]þ
¼ 368.1028, C13H24NO7P2 requires 368.1028.
found
4.2.6. N,N-Bis(diethoxyphosphonylmethyl)-4-methoxyaniline (2b)
Yield: 89% (0.64 g); 31P NMR (CDCl3) : 23.9; 13C NMR (CDCl3)
d d:
16.6 (t, 3JCP ¼ 2.7, CH2CH3), 47.8 (d, 1JCP ¼ 157.5, CH2P), 55.8 (CH3O),
2
62.2 (t, JCP ¼ 3.4, OCH2), 114.5 (C3)*, 116.0 (C2)*, 142.4 (C1), 152.9
3
(C4), *may be reversed; 1H NMR (CDCl3)
d
: 1.22 (t, JHH ¼ 7.1, 12H,
4.2. General procedure for the preparation of bis(pP(O)CH2)amines
CH2CH3), 3.71 (s, 3H, CH3O), 3.87 (d, 2JPH ¼ 5.6, 4H, CH2P), 3.97e4.08
(m, 8H, CH2CH3), 6.75e6.78 and 6.87e6.90 (m, 4H, ArH);
A mixture of 1.70 mmol amine (0.19 mL of benzylamine or 0.21 g
of 4-methoxyaniline), 3.40 mmol (0.10 g) of paraformaldehyde and
3.40 mmol of the pP(O)H species (0.31 mL of dimethyl phosphite,
0.44 mL of diethyl phosphite, 0.67 mL of dibutyl-phosphite and
0.75 mL of dibenzyl phosphite) was heated at 100 ꢀC in a vial in
a CEM Discover Microwave reactor equipped with a pressure
controller for 1 h. The water formed was removed in vacuum.
Column chromatography (silica gel 3% methanol in chloroform) of
the residue afforded the products (1aee and 2aed) as oils. The
following products were thus prepared:
[M þ H]þ
¼ 424.1649, C17H32NO7P2 requires 424.1654.
found
4.2.7. N,N-Bis(dibutoxyphosphonylmethyl)- 4-methoxyaniline (2c)
Yield: 85% (0.77 g); 31P NMR (CDCl3) : 24.7; 13C NMR (CDCl3)
d d:
13.8 (CH2CH3), 18.9 (CH2CH3), 32.8 (t, 3JCP ¼ 2.8 OCH2CH2), 47.7 (d,
1JCP ¼ 157.1, CH2P), 55.9 (CH3O), 66.0 (t, 2JCP ¼ 3.5, OCH2),114.6 (C3)*,
116.1 (C2)*, 142.5 (C1), 152.9 (C4), *may be reversed; 1H NMR (CDCl3)
3
d
: 0.90 (t, JHH ¼ 7.4, 12H, CH2CH3), 1.28e1.41 (m, 8H, CH2CH3),
2
1.53e1.63 (m, 8H, OCH2CH2), 3.91 (d, JPH ¼ 5.2, 4H, CH2P),
3.94e4.05 (m, 8H, OCH2), 6.79e6.82 and 6.91e6.94 (m, 4H, ArH);
[M þ H]þ
¼ 536.2908, C25H48NO7P2 requires 536.2906.
found
4.2.1. N,N-Bis(dimethoxyphosphonylmethyl)benzylamine (1a)
Yield: 82% (0.49 g); 31P NMR (CDCl3)
d
: 27.3; 13C NMR (CDCl3)
d:
4.2.8. N,N-Bis(dibenzyloxyphosphonylmethyl)-4-methoxyaniline
1
3
48.9 (dd, JCP ¼ 158.0, JCP ¼ 7.7, CH2P), 52.8 (m, OCH3), 61.3 (t,
(2d)
3JCP ¼ 7.7, CH2N), 127.8 (C4), 128.6 (C3)*, 129.5 (C2)*, 138.0 (C1), *may
Yield: 81% (0.79 g); 31P NMR (CDCl3) : 25.0; 13C NMR (CDCl3)
d d:
be reversed; 1H NMR (CDCl3)
d
: 3.17 (d, JPH ¼ 9.4, 4H, CH2P), 3.74
49.4 (OCH3), 55.9 (CH2P), 67.8 (m, OCH2), 114.7 (C3)a, 116.4 (C2)a,
2
3
b
b
3
0
0
0
(d, JPH ¼ 10.7, 12H, OCH3), 3.95 (s, 2H, CH2N), 7.26e7.39 (m, 5H,
128.3 (C3 ) , 128.6 (C4 ), 128.8 (C2 ) , 136.3 (d, JCP ¼ 2.7) and 136.4
ArH); [M þ H]þ
¼ 352.1083, C13H24NO6P2 requires 352.1079.
(d, JCP ¼ 2.9) (C1 ), 142.1 (C1), 153.2 (C4), a,bmay be reversed; 1H
3
0
found
2
NMR (CDCl3)
d
: 3.73 (s, 3H, CH3O), 3.84 (d, JHP ¼ 9.0, 4H, CH2P),
4.2.2. N,N-Bis(diethoxyphosphonylmethyl)benzylamine (1b)
4.89e4.96 (m, 8H, OCH2), 6.71e6.74 and 6.84e6.87 (m, 4H, ArH),
Yield: 98% (0.68 g); 31P NMR (CDCl3)
d
: 26.1; 13C NMR (CDCl3)
d:
7.21e7.37 (m, 20H, Ar’H); [M þ H]þ
¼ 672.2285, a C37H40NO7P2
found
3
16.6 (m, CH2CH3), 49.7 (dd, 1JCP ¼ 156.0, JCP ¼ 6.7, CH2P), 61.2 (t,
requires 672.2280.
3JCP ¼ 7.9, CH2N), 62.1 (m, CH2CH3), 127.6 (C4), 128.4 (C3)*, 129.4 (C2)
*, 138.2 (C1), *may be reversed; 1H NMR (CDCl3)
d
: 1.31 (t, 3JHH ¼ 6.9,
4.2.9. N,N-Bis(ethoxy-phenylphosphinylmethyl)benzylamine (1e)
Compound 1e was prepared similarly using the same amount of
benzylamine and paraformaldehyde along with 3.40 mmol
(0.51 mL) of ethyl phenylphosphonate. Yield: 97% (0.78 g) (oil as
2
12H, CH2CH3), 3.16 (d, JPH ¼ 9.4, 4H, CH2P), 3.97 (s, 2H, CH2N),
4.07e4.16 (m, 8H, CH2CH3), 7.25e7.39 (m, 5H, ArH);
[M þ H]þ
¼ 408.1706, C17H32NO6P2 requires 408.1705.
found
a 51:49 mixture of two isomers); 31P NMR (CDCl3)
d: 41.2 and 41.3;
4.2.3. N,N-Bis(dibutoxyphosphonylmethyl)benzylamine (1c)
Yield: 98% (0.87 g); 31P NMR (CDCl3) : 25.1; 13C NMR (CDCl3)
13C NMR (CDCl3)
d
: 16.7 and 16.8 (CH2CH3), 53.9 (dd, 1JCP ¼ 126.3,
3
d
d:
3JCP ¼ 8.9) and 54.0 (dd, 1JCP ¼ 123.9, JCP ¼ 8.0) (CH2P), 60.7 and
13.8 (CH2CH3), 18.9 (CH2CH3), 32.8 (m, OCH2CH2), 49.6 (dd,
60.9 (m, CH2CH3), 61.8 and 61.9 (m, CH2N), 128.2 (C4), 128.3 (d,
3
3
a
b
b
1JCP ¼ 156.1, JCP ¼ 7.3, CH2P), 61.1 (t, JCP ¼ 7.9, CH2N), 65.8 (m,
JCP ¼ 11.7) and 128.6 (d, JCP ¼ 12.6) (C2 ) , 128.5 (C3) , 129.3 (C2) ,
0
1
1
0
OCH2), 127.6 (C4), 128.4 (C3)*, 129.4 (C2)*, 138.2 (C1), *may be
130.0 (d, JCP ¼ 123.8) and 130.6 (d, JCP ¼ 122.6) (C1 ), 132.1 (d,

E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
81
4
4
0
JCP ¼ 2.7) and 132.2 (d, JCP ¼ 2.7) (C4 ), 132.3 (d, JCP ¼ 10.1) and
degassed benzene. To the solution of phosphine 5 so obtained was
added 0.18 g (0.37 mmol) of dichlorodibenzonitrile platinum and
the mixture stirred at 25 ꢀC for 1 day. The solid crystallized from the
mixture was separated by filtration to afford complex 6aed.
132.5 (d, JCP ¼ 10.0) (C3 ) , 137.9 (C1); 1H NMR (CDCl3)
d: 1.25 (t,
a
0
3JHH ¼ 7.0, 6H, CH2CH3), 3.00e3.08 (m, 2H) and 3.39e3.51 (m, 2H)
CH2P, 3.77e3.87 (m, 2H) and 3.98e4.09 (m, 2H) CH2CH3, 3.96 (s, 2H,
CH2N), 6.91e7.71 (m, 15H, ArH), a,bmay be reversed;
[M þ H]þ
¼ 472.1807, C25H32NO4P2 requires 472.1807.
4.4.1. Bis(diphenylphosphinomethyl)benzylamine]-dichloro-
found
platinum(II) (6a)
4.3. General procedure for the synthesis of N,N-
bis(diphenylphosphinoylmethyl)amines 3aed
Yield: 60%; 31P NMR (CDCl3)
d
: ꢂ7.9 (1JP,Pt ¼ 3395); 13C NMR
(CDCl3)
d
: 55.7 (dd, 1JCP ¼ 62.0, 3JCP ¼ 5.7, CH2P), 69.9 (t, 3JCP ¼ 12.1,
CH2N), 127.9 (dd, 1JCP ¼ 72.0, JCP ¼ 5.7, C1 ), 128.4 (C4), 128.59 (d,
3
0
4
a
b
b
JCP ¼ 5.7), 128.63 (d, 4JCP ¼ 5.7) (C3 ) , 128.9 (C3) , 129.9 (C2) , 131.6
0
A mixture of 0.85 mmol of the amine (0.09 mL of benzylamine,
0.105 g of 4-methoxyaniline, 0.08 mL of aniline and 0.09 mL of 4-
methylaniline), 1.70 mmol (0.05 g) of paraformaldehyde,
1.70 mmol (0.34 g) of diphenylphosphine oxide and 3 mL of aceto-
nitrile was heated at 100 ꢀC in a closed vial in the MW reactor for
1.5 h. The work-up was similar as above to provide products 3aed.
(C4 ), 133.98 (d, JCP ¼ 4.9), 134.01 (d, 5JCP ¼ 4.9) (C2 ) , 135.2 (C1); H
5
a
1
0
0
2
3
NMR (CDCl3)
d
: 3.42 (d, JHP ¼ 2.5, JHPt ¼ 36.4, 4H, CH2P), 3.59 (s,
4 3
2H, CH2N), 6.92 (d, JHH ¼ 7.5, 2H, C2H)a, 7.20 (t, JHH ¼ 7.3, 2H,
C3H)a, 7.28 (t, 4JHH ¼ 7.5, C4H), 7.34 (t, 3JHH ¼ 7.5, 8H, C3 H) , 7,44 (t,
b
0
3
3
3
b
0
0
JHH ¼ 7.2, 4H, C4 H), 7.70 (dd, JHH ¼ 7.5, JPH ¼ 10.7, 8H, C2 H) ,
a,bmay be reversed; [M ꢂ Cl]þ
¼ 732.1269, C33H31NP2PtCl
found
4.3.1. N,N-Bis(diphenylphosphinoylmethyl)benzylamine (3a)
Yield: 95% (0.86 g) of compound 3a as white crystals. Mp:
requires 732.1247.
80e82 ꢀC; 31P NMR (CDCl3)
d
: 29.8; 13C NMR (CDCl3)
d: 55.1 (dd,
4.4.2. Bis(diphenylphosphinomethyl) 4-methoxyaniline]-dichloro-
1JCP ¼ 84.4, JCP ¼ 7.7, CH2P), 63.1 (t, JCP ¼ 7.7, CH2N), 127.3 (C4),
platinum(II) (6b)
3
3
128.1 (C3)a, 128.4 (d, JCP ¼ 12.3, C3 ) , 129.8 (C2) , 131.2 (d, JCP ¼ 9.2,
Yield: 50%; 31P NMR (CDCl3)
d
: ꢂ6.3 (1JP,Pt ¼ 3410); 13C NMR
b
a
0
b
4
1
1
C2 ) , 131.6 (d, JCP ¼ 2.2, C4 ), 132.0 (d, JCP ¼ 98.0, C1 ); 137.6 (C1); H
(CDCl3) d
: 56.0 (dd, 1JCP ¼ 58.0, 3JCP ¼ 5.5, CH2P), 55.8 (OCH3), 115.2
0
0
0
2
1
3
(C3)a, 122.6 (C2)a, 127.8 (dd, JCP ¼ 70.4, JCP ¼ 5.6, C1 ), 128.76 (d,
0
NMR (CDCl3)
d
: 3.74 (d, JPH ¼ 6.4, 4H, CH2P), 4.09 (s, 2H, CH2N),
(m, 25H, ArH), be reversed;
a,bmay
¼ 536.1905, C33H32NO2P2 requires 536.1908.
4
5
4
b
0
0
6.80e7.66
JCP ¼ 5.7), 128.84 (d, JCP ¼ 5.7) (C3 ) , 131.8 (C4 ), 134.07 (d,
[M þ H]þ
JCP ¼ 4.9), 134.13 (d, 5JCP ¼ 4.9) (C2 ) , 146.7 (C1), 156.9 (C4); H NMR
b
1
0
found
2
3
(CDCl3)
d
: 3.74 (s, 3H, CH3O), 3.91 (d, JHP ¼ 0.9, JHPt ¼ 19.7, 4H,
4.3.2. N,N-Bis(diphenylphosphinoylmethyl) 4-methoxyaniline (3b)
Yield: 94% (0.87 g) of compound 3b as white crystals. Mp:
CH2P), 6.67 (d, 4JHH ¼ 8.9, 2H, C3H)a, 6.76 (d, 3JHH ¼ 8.8, 2H, C3H)a,
7.40 (t, 3JHH ¼ 6.8, 8H, C3 H) , 7,45 (t, JHH ¼ 6.9, 4H, C4 H), 7.83 (dd,
b
3
0
0
158e160 ꢀC; 31P NMR (CDCl3)
d
: 28.1; 13C NMR (CDCl3)
d: 54.6 (d,
3JHH
¼
7.6, JPH
¼
17.9 8H, C2 H) , a,bmay be reversed;
3
b
0
1JCP ¼ 77.3, CH2P), 55.7 (CH3O), 114.3 (C3)a, 122.0 (C2)a, 128.7 (d,
[M ꢂ Cl]þ
¼ 748.1196, C33H31NOP2PtCl requires 748.1196.
found
b
b
0
0
0
JCP ¼ 11.5, C3 ) , 131.3 (d, JCP ¼ 9.4, C2 ) , 132.0 (C4 ), 132.2 (d,
1
2
4
JCP ¼ 95.9, C1 ), 146.7 (dd, JCP ¼ 6.0, JCP ¼ 2.9, C1), 155.0 (C4); 1H
4.4.3. Bis(diphenylphosphinomethyl)aniline]-dichloro-platinum(II)
0
NMR (CDCl3)
d
: 3.66 (s, 3H, OCH3), 4.41 (s, 4H, CH2P), 6.50e6.53 (m,
(6c)
2H, C3H)a and 6.72e6.75 (m, 2H, C2H)a, 7.34e7.69 (m, 20H, Ar’H),
Yield: 45%; 31P NMR (CDCl3)
d
: ꢂ5.4 (1JP,Pt ¼ 3422); 13C NMR
a,bmay be reversed; [M þ H]þ
¼ 552.1863, C33H32NO3P2
(CDCl3)
d
: 52.7 (dd, 1JCP ¼ 57.4, JCP ¼ 4.9, CH2P), 118.9 (C2), 123.4
3
found
4
(C4), 127.7 (dd, 1JCP ¼ 122.9, 3JCP ¼ 5.7, C1 ), 128.9 (d, JCP ¼ 5.6), 129.0
0
requires 552.1857.
(d, 4JCP ¼ 5.6) (C3 ) , 130.0 (C3) 132.0 (C4 ), 134.0 (d, JCP ¼ 4.9), 134.1
a
5
0
0
a
1
(d, 5JCP ¼ 4.8) (C2 ) , 156.7 (C1); H NMR (CDCl3)
d
: 4.08 (d, 2JHP ¼ 1.2,
0
4.3.3. N,N-Bis(diphenylphosphinoylmethyl)aniline (3c)
Yield: 55% (0.48 g) of compound 3c as white crystals. Mp:
3JHPt ¼ 21.3, 4H, CH2P), 6.69 (d, 4JHH ¼ 8.1, 2H, C3H)a, 6.89e6.93 (m,
190e192 ꢀC; 31P NMR (CDCl3)
d
: 27.6; 13C NMR (CDCl3)
d: 52.2 (d,
1H, C4H), 7.03 (d, 3JHH ¼ 7.4, 2H, C3H)a, 7.44 (t, 3JHH ¼ 6.7, 8H, C3 H) ,
b
0
1JCP ¼ 76.2, CH2P), 116.7 (C2), 119.7 (C4), 128.5 (C3), 128.6 (d,
7.49 (t, JHH ¼ 6.8, 4H, C4 H), 7.85 (dd, JHH ¼ 7.8, JPH ¼ 17.7 8H,
3
3
3
0
a
a
b
JCP ¼ 11.5, C3 ) , 131.1 (d, JCP ¼ 9.3, C2 ) , 131.99 (C4 ), 132.02 (d,
C2 H) , a,bmay be reversed; [M
ꢂ
Cl]þ
¼
718.1101,
0
0
0
0
found
1
JCP ¼ 94.2, C1 ), 148.8 (C1); 1H NMR (CDCl3)
d: 4.50 (s, 4H, CH2P),
C32H29NP2PtCl requires 718.1091.
0
6.68e6.71 (m, 2H, C3H)a and 6.91e6.94 (m, 2H, C2H)a, 7.36e7.73 (m,
20H, Ar’H), amay be reversed; [M
þ
H]þ
¼
522.1741,
4.4.4. Bis(diphenylphosphinomethyl)-4-methylaniline]-dichloro-
found
C32H30NO2P2 requires 522.1752.
platinum(II) (6d)
Yield: 60%; 31P NMR (CDCl3)
d
: ꢂ5.8 (1JP,Pt ¼ 3416); 13C NMR
3
4.3.4. N,N-Bis(diphenylphosphinoylmethyl)-4-methylaniline (3d)
Yield: 89% (0.81 g) of compound 3d as white crystals. Mp:
(CDCl3)
d
: 20.8 (CH3), 54.1 (dd, 1JCP ¼ 64.3, JCP ¼ 5.2, CH2P), 119.7
(C2), 127.6 (dd, 1JCP ¼ 76.4, 3JCP ¼ 6.0, C1 ), 128.8 (d, JCP ¼ 5.6), 128.9
4
0
165e167 ꢀC; 31P NMR (CDCl3)
d
: 28.0; 13C NMR (CDCl3)
d
: 20.6
(d, 4JCP ¼ 5.7) (C3 ) , 130.6 (C3) 131.9 (C4 ), 134.0 (d, JCP ¼ 4.9), 134.1
a
5
0
0
(CH3), 53.2 (d, 1JCP ¼ 76.8, CH2P), 118.3 (C2), 128.8 (d, JCP ¼ 11.4, C3 ) ,
(d, 5JCP ¼ 5.0) (C2 ) , 143.9 (C4), 150.2 (C1); H NMR (CDCl3)
d: 2.27 (s,
a
a
1
0
0
a
2
3
0
0
129.5 (C3), 130.0 (C4), 131.4 (d, JCP ¼ 9.3, C2 ) , 132.0 (C4 ), 132.3 (d,
3H, CH3), 4.00 (d, JHP ¼ 1.5, JHPt ¼ 20.0, 4H, CH2P), 6.62 (d,
1
1
JCP ¼ 94.5, C1 ), 147.2 (C1); H NMR (CDCl3)
d: 2.14 (s, 3H, CH3), 4.44
4JHH ¼ 8.3, 2H, C3H)a, 7.04 (d, 3JHH ¼ 8.2, 2H, C3H)a, 7.40 (t, 3JHH ¼ 7.9,
0
(s, 4H, CH2P), 6.63e6.66 (m, 2H, C3H)a and 6.75e6.78 (m, 2H, C2H)a,
7.35e7.72
[M þ H]þ
8H, C3 H) , 7.45 (t, JHH ¼ 6.7, 4H, C4 H), 7.85 (dd, JHH ¼ 8.3,
b
3
3
0
0
b
amay
be
reversed;
3JPH
¼
18.1
8H,
C2 H) ,
a,bmay
be
reversed;
0
(m,
20H,
Ar’H),
¼ 536.1908, C33H32NO2P2 requires 536.1908.
[M ꢂ Cl]þ
¼ 732.1269, C33H31NP2PtCl requires 732.1247.
found
found
4.4. General procedure for the synthesis of cis[(benzyl- or aryl-
bis(diphenylphosphinomethyl)amine)-dichloro-platinum(II)]
4.5. Hydroformylation experiments
In a typical experiment, a solution of 0.005 mmol of PtCl2(PNP
ligand) 6 (6a: 3.9 mg, 6b: 3.9 mg, 6d: 3.9 mg, 6e: 3.8 mg) and tin(II)
chloride (0.95 mg; 0.005 mmol) in toluene (5 mL) containing
styrene (0.058 mL, 0.5 mmol) was transferred under argon into
a 100 mL stainless steel autoclave. The reaction vessel was
To 0.36 mmol of 3aed (3a: 0.19 g, 3b: 0.20 g, 3c: 0.19 g, 3d:
0.19 g) in 1 mL of degassed benzene was added 1.35 mL (1.07 mmol)
of phenylsilane under nitrogen. The mixture was stirred at 80 ꢀC for
3 days. Then the mixture was diluted by the addition of 2 mL of

82
E. Bálint et al. / Journal of Organometallic Chemistry 717 (2012) 75e82
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pressurized to 80 bar total pressure (CO/H2 ¼ 1:1) and placed in an
oil bath of constant temperature. The mixture was stirred with
a magnetic stirrer for the given reaction time. The pressure was
monitored throughout the reaction. After cooling and venting of
the autoclave, the pale yellow solution was removed and immedi-
ately analyzed by GC and GCeMS.
4.6. X-ray experimental
A
selected colourless prism shaped single crystal
(0.2 ꢁ 0.3 ꢁ 0.1 mm) of 6b was mounted on a Rigaku R-AXIS RAPID
diffractometer (graphite monochromator CueK radiation,
¼ 1.54178 Å). Data collection was performed at low temperatures
(T ¼ 108(2) K). Crystal data for 6b: C34H33Cl4NOP2Pt, orthorhombic,
a
l
space group Pbca,
a
¼
13.8550(3) Å,
b
¼
21.8600(4) Å,
c ¼ 44.6567(8) Å, V ¼ 13525.2(4) Å3, T ¼ 108(2) K, Z ¼ 16,
[16] A.A. Prishchenko, M.V. Livantsov, O.P. Novikova, L.I. Livantsova, V.S. Petrosyan,
Heteroatom Chem. 21 (2010) 430.
[17] A.A. Prishchenko, M.V. Livantsov, D.N. Kustrya, E.V. Grigorev, Zh. Obshch.
Khimii 65 (1995) 1571.
F(000) ¼ 6848, Dx ¼ 1.710 Mg/m3,
m
¼ 11.791 mmꢂ1. Initial structure
model was obtained by SHELXS-97,2 completed by successive
difference Fourier syntheses and refined to convergence by
[18] S. Priya, M.S. Balakrishna, J.T. Mague, S.M. Mobin, Inorg. Chem. 42 (2003)
1272.
SHELXL-97,2 R1 ¼ 0.0616 and wR2 ¼ 0.1604 for 1332 [I > 2
s(I)] and
}
R1 ¼ 0.0697 and wR2 ¼ 0.1685 for all (11,723) intensity data. Crys-
tallographic data for 6b have been deposited at the Cambridge
Crystallographic Data centre under deposition no. CCDC 876164.
Copies of these data can be obtained free of charge upon applica-
tion to CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (fax: 00 44 (0)
1223 336033 or e-mail: deposit@ccdc.cam.ac.uk).
[19] G. Keglevich, A. Szekrényi, Á. Szöllosy, L. Drahos, Synth. Commun. 41
(2011) 2265.
}
[20] E. Bálint, E. Fazekas, G. Pintér, Á. Szöllosy, T. Holczbauer, M. Czugler, L. Drahos,
T. Körtvélyesi, G. Keglevich, Curr. Org. Chem. 16 (2012) 547.
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6908. and references cited therein.
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(1997) 1846.
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Chem. 696 (2011) 2234.
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therein.
[29] I. Ojima, C.-Y. Tsai, M. Tzamarioudaki, D. Bonafoux, in: L.E. Overman, et al.
(Eds.), Organic Reactions, vol. 56, Wiley, New York, 2000, pp. 1e354
(Chapter 1).
Acknowledgement
The above project was supported by the Hungarian Scientific
and Research Fund (OTKA K83118 and CK78553). Costs of the X-ray
diffraction investigations were covered partially by the Hungarian
Scientific and Research Fund (OTKA K75869).
References
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