The influence of the intramolecular hydrogen bond on the 1,3-N,S- and 1,5-O,S-coordination of N-phosphoryl-N′-(R)-thioureas with Ni(II) and Pd(II)

Article abstract of DOI:10.1039/b702896b

Reaction of the potassium salts of N-phosphorylated thioureas of common formula R¹-N(H)-C(S)-N(H)-P(O)(OiPr)₂ (HA) with Ni ^II and Pd^II cations leads to [MA₂] chelate complexes (M = Ni^II, R¹ = p-MeOC₆H₄, p-BrC₆H₄, t-Bu, c-Hex; M = Pd^II, R = iPr). In both the Ni^II and Pd^II complexes, the metal center is found in a square-planar N₂S₂ environment formed by the C=S sulfur atoms and the P-N nitrogen atoms of two deprotonated ligands A ^-. The Pd^II atoms in [PdB₂] complexes with deprotonated thioureas of common formula R²-C(S)-N(H)-P(O)(OiPr) ₂ (HB) (R² = Et₂N, morpholine-N-yl) are coordinated in a square-planar fashion by the C=S sulfur atoms and the P=O oxygen atoms of two anionic ligands. Molecular structures of four complexes [M(A-N,S)₂] (M = Ni^II, R¹ = p-MeOC ₆H₄, p-BrC₆H₄, t-Bu; M = Pd ^II, R¹ = iPr) and the palladium(II) 1,5-O,S-chelate of formula [Pd(B-O,S)₂] (R² = morpholine-N-yl) were elucidated by X-ray diffraction. The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.

Full text of DOI:10.1039/b702896b

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The influence of the intramolecular hydrogen bond on the 1,3-N,S- and
1,5-O,S-coordination of N-phosphoryl-N0-(R)-thioureas with Ni(II)
and Pd(II)
Felix D. Sokolov,*a Sergey V. Baranov,a Damir A. Safin,*ab F. Ekkehardt Hahn,b
Maria Kubiak,c Tania Pape,b Maria G. Babashkina,a Nail G. Zabirov,a
Joanna Galezowska,c Henryk Kozlowskic and Rafael A. Cherkasova
Received (in Montpellier, France) 26th February 2007, Accepted 24th May 2007
First published as an Advance Article on the web 15th June 2007
DOI: 10.1039/b702896b
Reaction of the potassium salts of N-phosphorylated thioureas of common formula
R1–N(H)–C(S)–N(H)–P(O)(OiPr)2 (HA) with NiII and PdII cations leads to [MA2] chelate
complexes (M = NiII, R1 = p-MeOC6H4, p-BrC6H4, t-Bu, c-Hex; M = PdII, R = iPr). In both
the NiII and PdII complexes, the metal center is found in a square-planar N2S2 environment
formed by the CQS sulfur atoms and the P–N nitrogen atoms of two deprotonated ligands Aꢀ.
The PdII atoms in [PdB2] complexes with deprotonated thioureas of common formula
R2–C(S)–N(H)–P(O)(OiPr)2 (HB) (R2 = Et2N, morpholine-N-yl) are coordinated in a square-
planar fashion by the CQS sulfur atoms and the PQO oxygen atoms of two anionic ligands.
Molecular structures of four complexes [M(A-N,S)2] (M = NiII, R1 = p-MeOC6H4, p-BrC6H4,
t-Bu; M = PdII, R1 = iPr) and the palladium(II) 1,5-O,S-chelate of formula [Pd(B-O,S)2]
(R2 = morpholine-N-yl) were elucidated by X-ray diffraction.
generated by of the amide Nꢀ atom in comparison with the
Introduction
PQO oxygen atom and (ii) the formation of intramolecular
The coordination chemistry of polyfunctional ligands, capable
to realize different coordination modes with metal cations1 is
NHꢁ ꢁ ꢁOQP hydrogen bonds in the complexes. DFT calcula-
tions have shown, that each intramolecular hydrogen bond
contributes around 20–25 kJ molꢀ1 5,6
The substantial con-
of interest for synthesis of new selective complexing agents and
.
analytical reagents. The reasons allowing such ligands to bind
metal ions in the various specific ways are intimately con-
nected with such fundamental questions of chemistry as the
nature of chemical bonding and the isomerism of coordination
compounds, as well as the influence of the ligand structure on
regio- and stereoselectivity of bond formation.
tribution of the hydrogen bonds towards the stability of the
resulting complexes makes these an essential factor for
1,3-N,S-coordination of N-phosphorylthioureas.
To verify the assumptions made above, we have carried out
the comparative study on the complexes of the NiII and PdII
ions with N-phosphorylthioureas (Scheme 1), containing sec-
ondary (HA) and tertiary (HB) nitrogen at the N-thioacyl-
amidophosphate moiety C(S)–N(H)–P(O)(OiPr)2 (NAAP).
N-(Thio)phosphinyl(thio)ureas of the common formula
RR0N–C(X)–N(H)–P(Y)(R00)2 (R, R0 = alkyl, aryl, H;
R00 = aryl, O-alkyl, O-aryl, N-alkyl2; X, Y = O, S), as a rule,
form 1,5-X,Y-chelates with metal cations.2–4 Recently, we
reported, that in the square-planar complexes of N-phos-
phrylthioureas [M{PhN(H)–C(S)–N–P(O)(OiPr)2}2], where
M = NiII or PdII,5 and [Cu{RN(H)–C(S)–N–P(O)(OiPr)2}2]
(R = Ph, c-Hex),6 1,3-N,S-coordination of the ligand is
realized.
Results and discussion
Nickel(II) chelates with the thioureas HA1–4 of the common
formula [Ni(A)2] were prepared as follows. The ligands were
We have proposed two reasons for the higher stability of the
[M(L-1,3-N,S)2] relative to [M(L-1,5-O,S)2] coordination
mode. These include (i) a higher crystal field stabilization
energies (CFSE) for the low-spin d8 [M{PhN(H)–C(S)–
NP(O)(OiPr)2-N,S}2] complexes due to a stronger ligand field
a A. M. Butlerov Chemistry Institute, Kazan State University,
Kremlevskaya Str. 18, 420008 Kazan, Russian Federation. E-mail:
felix.sokolov@ksu.ru, damir.safin@ksu.ru; Fax: +7-843-2543734
b Institut fur Anorganische und Analytische Chemie, Westfalische
¨
¨
Wilhelms-Universitat Munster, Corrensstrasse 36, D-48149 Munster,
¨
¨
¨
Germany. E-mail: fehahn@uni-muenster.de; Fax: +49-251-8333108
c Faculty of Chemistry, University of Wroclaw, F. Joliot-Curie Str.
14, 50383 Wroclaw, Poland
Scheme 1 Ligands of type HA and HB.
ꢂc
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Scheme 2 Preparation of complexes [Ni(A-N,S)2].
converted into the potassium salts KA1–4 which were reacted
with Ni(NO3)2 in aqueous EtOH (Scheme 2).
The compounds obtained were crystalline solids that are
soluble in most polar solvents. The molecular structures of
these compounds were investigated by electron impact mass-
spectrometry (EI-MS), IR, 1H, 31P{1H} NMR spectroscopy
and by elemental analysis. The NiII atom in these complexes
was found in a square-planar N2S2 environment formed by the
nitrogen and sulfur atoms of the N–P and CQS groups.
Application of the same procedure using the thioureas HB1
and HB2 did not result in isolation of individual products.
Scheme 3 Synthesis of palladium(II) complexes with ligands HA5,
HB1,2
.
plexes [Ni(A1–4-N,S)2] and [Pd(A5-N,S)2] are shifted by
4–32 cmꢀ1 to lower wave numbers in comparison to the parent
ligand. In contrast to this, involvement of the PQO oxygen
atoms in the coordination to the PdII ion in complexes [Pd-
(B-O,S)2] results in a decrease of the wave number for the
PQO stretching mode by 80 to 136 cmꢀ1. This shift compares
well with the data obtained for 1,5-O,S-chelates of the ZnII,7b
and CoII 5,8 ions with NAAP ligands.
The N–H absorption bands in the 1,3-N,S-chelates of NiII
and PdII are observed in the range of n 3120–3192 cmꢀ1 which
is the characteristic range for amide protons participating in
hydrogen bonds. The IR spectra of complexes [Pd(B-O,S)2]
exhibit no absorption bands in this region.
1
According to the H NMR spectra a complicated mixture of
complex species formed which was difficult to analyze.
Earlier studies on the 1,5-S,S0-complexes of the NiII ion
with N-thiophosphorylated thiourea PhN(H)–C(S)–N(H)–
7a
P(S)(OiPr)2 in CD2Cl2 solution have shown that a multi-
component equilibrium between complex species with a tetra-
hedral or square-planar coordination geometry around the
tetracoordinated metal ion. In these cases the product mixture
can become even more complicated due to the formation of
the five- and six-coordinated NiII species which might exhibit a
1,5-O,S- or 1,3-N,S-type of coordination.
Palladium(II) complexes were prepared from ligands HA5,
HB1 and HB2 by conversion of the ligands into their potas-
sium salts and subsequent reaction with [PdCl2(PhCN)2] in an
aqueous EtOH/CH3CN solution (Scheme 3).
Table 1 Comparison of IR and 31P{1H} spectroscopy data for
1,5-O,S- and 1,3-N,S-chelates of N-phosphorylthioureas
Dn(PO)c
n(NH)
DdP
Ref.
c
HA1
3120, 3272
3160
3296
3160, 3248
3120
3304
3128, 3288
3184
3328
3160, 3280
3192
3312
7b
[Ni(A1)2]a
[Zn(A1)2]
HA2
4
108
9.11
13.40
The complexes obtained are crystalline solids that are
soluble in most polar solvents and insoluble in n-hexane. They
were investigated by electron impact mass-spectrometry (EI-
7b
7b
[Ni(A2)2]a
[Zn(A2)2]
HA3
32
100
7.62
12.00
7b
7b
1
MS), IR, H, 31P{1H} NMR spectroscopy and by elemental
[Ni(A3)2]a
[Zn(A3)2]
HA4
20
92–128
8.43
12.10
analysis. A comparative analysis of the spectral characteristics
indicated, that the PdII atom in [Pd(A5)2] is coordinated in a
square-planar N2S2 environment whereas the [Pd(B)2] com-
plexes contain two anionic ligands bound in the 1,5-O,S-
coordination mode. Apparently, the inability of coordinated
ligands Bꢀ to form intramolecular hydrogen-bonds leads to a
destabilization of the [M(B-N,S)2] complexes and the forma-
tion of complexes containing the ligand in the 1,5-O,S-co-
ordination mode.
7b
7b
[Ni(A4)2]a
[Zn(A4)2]
HA5
12
88
7.51
11.90
7b
7b
3144, 3272
3208
[Pd(A5)2]a
[Zn(A5)2]
HB1
4
80–112
7.84
9.6
7b
7b
3128
3128
[Pd(B1)2]a
[Zn(B1)2]
HB2
100
105–136
13.26
9.6
7b
7b
The molecular structures of four trans-1,3-N,S-chelates
[Ni(A1)2], [Ni(A2)2], [Ni(A3)2], [Pd(A5)2] and one cis-1,5-O,S-
chelate complex [Pd(B2)2] were determined by single-crystal
X-ray diffraction analysis confirming the conclusions derived
form the spectroscopic analysis.
[Pd(B2)2]a
[Zn(B2)2]
HLb
81
116–132
13.69
10.2
7b
5
5
5
7b
3096, 3300
3152
3160
[Ni(L)2]
[Pd(L)2]
[Zn(L)2]
a
14
10
100–114
7.01
7.99
11.6
3312
The coordination mode of the ligands can be reliably
followed by the IR spectroscopy (Table 1). The absorption
bands of the PQO group of the anionic ligand Aꢀ in com-
b
c
This work. HL = PhN(H)–C(S)–N(H)–P(O)(OiPr)2. Difference
between values for the free and coordinated ligand.
ꢂc
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and torsion angles for these complexes are summarized in
Table 2.
The NiII and PdII ions in [Ni(A1–3-N,S)2] and [Pd(A5-N,S)2]
(Fig. 4) chelates are coordinated in a square-planar fashion
with the ligands arranged in trans-configuration. The four-
membered M–S–C–N metallocycles are flat. The values of the
intracyclic S–Ni–N angles in the four-membered rings fall in
the range of 70–751. Inspection of the C–S and P–N bond
lengths indicates, that these bonds are best described as single
bonds, while the PQO separation indicates the presence of a
double bond.9
In all investigated compounds the RN(H) protons
are engaged in intramolecular hydrogen bonds of the
RNHꢁ ꢁ ꢁOQP type (Table 3). Due to their formation, a flat
syn,syn-conformation of the N–C–N–P–O unit is favored.
Fig. 1 Molecular structure of [Ni(A1)2]. Thermal ellipsoids are drawn
at 50% probability.
1
Only one NH-proton signal was observed in the H NMR
spectra of complexes [Ni(A1–4-N,S)2] and [Pd(A5-N,S)2]. For
the complexes of the thioureas HA3–5, containing alkyl sub-
stituents at the nitrogen atom, the amide proton resonance was
observed in the range d 8.47–8.55 ppm, while in the case of
thioureas HA1 and HA2 the influence of the phenyl group in
combination with its deshielding effects results in a shift of this
signal to the d 10.30–10.55 ppm range. In the 31P{1H} spectra a
singlet signal with a chemical shift characteristic for the amido-
phosphate environment of the phosphorus nuclei (Table 1)
was observed. These signals are low-field shifted in compar-
ison to the corresponding resonance of the parent phosphory-
lated thiourea. As can been seen in Table 1, the 31P{1H}
resonance in the 1,5-O,S-chelates is always observed at higher
field than for the 1,3-N,S-analogues.
Crystals of [Ni(A1–3-N,S)2], and [Pd(A5-N,S)2] and [Pd-
(B2-N,O)2] were obtained by slow evaporation of the solvent
from dichloromethane–n-hexane solutions of the complexes.
The complexes [Ni(A1,2)2] (Fig. 1 and 2) are built in a
centrosymmetric manner. The asymmetric unit of [Ni(A3)2]
contains two independent molecules which also possess a
center of symmetry (Fig. 3). Selected bond lengths and bond
Fig. 3 Crystal structure of two independent centrosymmetrical
molecules (A) and (B) in a crystal of complex [Ni(A3)2]. Thermal
ellipsoids are drawn at 50% probability.
Fig. 2 Molecular structure of [Ni(A2)2]. Thermal ellipsoids are drawn
at 50% probability.
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Table 2 Selected bond lengths (A), and bond angles (1) for four-membered cycles M–S–C–N in complexes [Ni(A1–3-N,S)2] and [Pd(A5-N,S)2], and
six-membered M–S–C–N–P–O cycles in [Pd(B2-O,S)2]
[Ni(A3)2]a [Ni(A3)2]a
a
a
[Ni(A1)2]
[Ni(A2)2]
(A)
(B)
[Ni(L)2]b,5
[Pd(A5)2]
[Pd(B2)2] (A) [Pd(B2)2] (B)
[Pd(L)2]5
M–S
M–N
M–O
C–S
2.2440(11) 2.2277(9)
2.2130(9)
2.2192(13)
2.2209(13), 2.3279(11),
2.2624(14),
2.2497(14)
2.2574(14),
2.2518(14)
2.3323(8),
2.3306(8)
2.0284(15),
2.0307(15)
2.2203(13)
1.907(3),
1.906(3)
2.3580(11)
2.034(3),
2.030(3)
1.912(3)
1.909(2)
1.896(2)
1.895(3)
2.060(3),
2.074(3)
1.757(5),
1.767(5)
1.311(6),
1.304(6)
1.356(6),
1.344(6)
1.592(4),
1.596(4)
1.503(4),
1.511(4)
2.074(3),
2.060(3)
1.751(5),
1.768(5)
1.304(6),
1.305(6)
1.351(6),
1.356(6)
1.594(4),
1.587(4)
1.491(4),
1.509(4)
1.713(4)
1.362(5)
1.335(5)
1.646(3)
1.475(3)
1.725(3)
1.342(4)
1.432(4)
1.653(2)
1.482(2)
1.741(3)
1.354(4)
1.313(4)
1.661(2)
1.460(2)
1.716(3)
1.353(4)
1.329(4)
1.645(3)
1.476(2)
1.732(4),
1.737(4)
1.332(4),
1.342(4)
1.337(4),
1.329(4)
1.655(3),
1.647(3)
1.471(2),
1.471(2)
1.738(4),
1.739(4)
1.342(5),
1.347(5)
1.320(5),
1.321(5)
1.650(3),
1.648(3)
1.475(3),
1.472(3)
1.7382(19),
1.7347(18)
1.330(2),
1.332(2)
1.338(2),
1.337(2)
1.6548(16),
1.6459(16)
1.4664(14),
1.4713(14)
C–N
C–N
(exocyclic)
P–N
PQO
N–C–S
(endocyclic)
S–M–X
(endocyclic),
(X = N, O)
a
110.6(3)
110.1(2)
74.74(8)
108.3(2)
75.20(8)
107.9(2)
74.04(9)
109.64(13), 109.4(3),
126.8(4),
127.0(4)
93.48(10),
95.14(10)
126.9(4),
127.4(4)
96.75(10),
93.28(10)
109.1(3),
108.5(3)
70.16(5),
70.18(5)
109.78(13)
74.36(9),
74.50(9)
110.2(3)
70.45(9),
70.33(9)
74.74(10)
b
The data for two independent molecules (A) and (B). HL = PhN(H)–C(S)–N(H)–P(O)(OiPr)2.
Table 3 Parameters of hydrogen bonds for NiII and PdII chelates
[bond lengths (A), and bond angles (1)]
Complex [Pd(B2)2] is a spirocyclic bis-chelate (Fig. 5) with a
cis-square-planar arrangement of the ligands around the PdII
ion. The deprotonated thiourea ligands are coordinated by the
oxygen atoms of the phosphoryl groups and the thiocarbonyl
sulfur atoms.
The asymmetric unit of [Pd(B2)2] contains two independent
molecules (A) and (B) differs by the mutual arrangement of the
morpholine substituents.
N–Hꢁ ꢁ ꢁA
d(Hꢁ ꢁ ꢁA) d(Nꢁ ꢁ ꢁA) +(NHA)
[Ni(A1)2] N(2)–H(2)ꢁ ꢁ ꢁO(3)
[Ni(A2)2] N(2)–H(2)ꢁ ꢁ ꢁO(3)
[Ni(A3)]2 N(1)ꢁ ꢁ ꢁH(1)ꢁ ꢁ ꢁO(12)
N(2)ꢁ ꢁ ꢁH(2)ꢁ ꢁ ꢁO23
2.04
2.04
2.05
2.05
2.761(4) 138
2.742(3) 139
2.777(3) 139
2.780(4) 140
2.849(4) 133
2.769(5) 138
[Pd(A5)2] N(12)–H(12N)ꢁ ꢁ ꢁO(31) 2.17
N(22)–H(22N)ꢁ ꢁ ꢁO(32) 2.07
All of the morpholine cycles are found in quite similar chair
conformations. The molecule (A) (Fig. 5) has the ‘‘parallel’’
orientation of the two morpholine moieties, deflected to the
same side of the PdO2S2 plane. The morpholine rings in the
molecule (B) are in anti-orientation about the PdO2S2 plane.
The six-membered metallocycles Pd–S–C–N–P–O adopt a
half-chair conformation and show a similar geometry. Both of
them have nearly planar S–C–N–P and Pd–S–C–N moieties.
The differences in the coordination of the ligands Aꢀ and Bꢀ
is reflected in the observed bond lengths within the chelate
Fig. 4 Crystal structure of [Pd(A5)2]. Thermal ellipsoids are drawn at
Fig. 5 Crystal structure of [Pd(B2)2]. The molecule (A) is shown.
50% probability.
Thermal ellipsoids are drawn at 50% probability.
ꢂc
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cycles. Predictably, coordination of the phosphoryl groups to
palladium(II) leads to an appreciable reduction of the P–N
bond lengths and an increase in length for the PQO bond
(Table 2) in comparison with the 1,3-N,S-chelates. The C–S
bonds in six-membered metallocycles are longer, and the C–N
bonds are shorter, than in four-membered ones. These changes
are a consequence of the negative charge delocalization in the
S–C–N–P–O ring.4a
Syntheses
HA1–HA5 and HB1,2. N-Diisopropoxyphosphorylthioureas
were prepared according to the previously described
methods.5,7b
[Ni(A1–4)2]. A suspension of HA1–4 (1.730, 1.975, 1.480 or
1.610 g, respectively; 5 mmol) in aqueous ethanol (20 mL) was
mixed with an ethanol solution of potassium hydroxide (0.280 g,
5 mmol). An aqueous (20 mL) solution of Ni(NO3)2 ꢁ 6H2O
(0.815 g, 2.8 mmol) was added dropwise under vigorous
stirring to the resulting potassium salt. The mixture was stirred
at room temperature for a further 5 h and left overnight. The
resulting complex was extracted with dichloromethane,
washed with water and dried with anhydrous MgSO4. The
solvent was then removed in vacuo. A precipitate was isolated
from dichloromethane by n-hexane.
The 1,5-O,S-coordination mode leads to a considerably
larger bite angle (Oꢁ ꢁ ꢁS separation 3.15–3.19 A) than the
N,S-coordination (Nꢁ ꢁ ꢁS separation 2.50–2.54 A) which re-
sults in a smaller distortion of the square-planar environment
at the central metal ion and the thiourea backbone geometry.
A comparison of the S–C–N and S–Pd–X (X = N, O) angles is
presented in Table 2.
[Ni(A1)2]. Yield (based on the ligand) 1.571 g (84%). Mp
1
3
171 1C. H NMR (CDCl3): d 1.36 (d, JH,H = 6.3 Hz, 12 H,
CH3), 1.64 (d, JH,H = 6.3 Hz, 12 H, CH3), 3.80 (s, 6 H,
Conclusions
3
The data presented allow to confirm, that at least for the
investigated N-phosphorylthiourea ligands (Scheme 1) the
formation of the intramolecular hydrogen bonds
PQOꢁ ꢁ ꢁHNR is a necessary condition for the 1,3-N,S-isomer
stabilization in a square-planar complexes of NiII and PdII.
When H-bonding in the coordinated anionic ligands (B1)ꢀ and
(B2)ꢀ is not possible the destabilization of NiII complexes and
a change of the coordination mode in the PdII complexes
occurs. Thus, the intramolecular hydrogen bonding realized
outside the coordination sphere of the metal cation is the
reason for the dramatic changes of such important parameters
as bite angle and ligand’s field strength.
3
3
OCH3), 4.66 (d sept, JH,H E JP,H = 6.3 Hz, 4 H, OCH),
6.86–7.29 (m, 8 H, C6H4), 10.30 [s, 2 H, NHC(S)] ppm.
31P{1H} NMR (CDCl3): d 2.2 ppm. IR: n~ 992 (POC), 1240
(PQO), 1552 (SCN), 3160 (NH) cmꢀ1. EI-MS: m/z (%) 748
(24) [M]+. C28H44N4O8P2S2Ni (748.14): calc. C 44.87, H 5.92,
N 7.48; found: C 44.81, H 5.86, N 7.39%.
[Ni(A2)2]. Yield (based on the ligand) 1.139 g (54%). Mp
1
3
175 1C. H NMR (CDCl3): d 1.32 (d, JH,H = 6.3 Hz, 12 H,
CH3), 1.60 (d, 3JH,H = 6.3 Hz, 12 H, CH3), 4.61 (d. sept, 3JH,H
E
3JP,H = 6.3 Hz, 4 H, OCH), 7.28–7.48 (m, 8 H, C6H4),
10.55 [s, 2 H, NHC(S)] ppm. 31P{1H} NMR (CDCl3): d
1.8 ppm. IR: n~ 1012 (POC), 1192 (PQO), 1548 (SCN), 3120
(NH) cmꢀ1. EI-MS: m/z (%) 844 (11) [M]+. C26H38-
Br2N4O6P2S2Ni (843.94): calc. C 36.86, H 4.52, N 6.61; found:
C 36.80, H 4.44, N 6.58%.
Factors, influencing on the stabilization of the 1,3-N,S-
isomers, essentially distinguish the NAAP ligands from their
diphosphorus analogues—imidodiphosphinates R2P(X)–
N(H)–P(Y)R02.10,11 The determining factor in the latter case
is the presence of the acceptor substituents at the PQO group
(X = O, Y = S, R = O-aryl). It is known, that for the PdII
[Ni(A3)2]. Yield (based on the ligand) 1.004 g (62%). Mp
1
131 1C. H NMR (CDCl3): d 1.26–1.49 (m, 24 H, CH3), 1.61
complexes with (PhO)2P(O)–N(H)–P(S)R0 (R0 = OPh,12
2
(s, 18 H, CH3, tBu), 4.52–4.75 (m, 4 H, OCH), 8.47 [s, 2 H,
NHC(S)] ppm. 31P{1H} NMR (CDCl3): d 2.0 ppm. IR: n~ 980,
1016 (POC), 1216 (PQO), 1564 (SCN), 3184 (NH) cmꢀ1. EI-
MS: m/z (%) 649 (10) [M]+. C22H48N4O6P2S2Ni (648.18):
calc. C 40.69, H 7.45, N 8.63; found: C 40.64, H 7.40, N
8.69%.
Ph,13 iPr13) the 1,3-N,S-coordination mode is realized. Similar
ligands, containing the Ph2P(O) group, form 1,5-O,S-chelates
both with the NiII and PdII ions.14
Experimental
[Ni(A4)2]. Yield (based on the ligand) 0.963 g (55%). Mp
175 1C. 1H NMR (CDCl3): d 1.37–2.03 (m, 44 H, CH3
+
General procedures
c-C6H11 (without CHN)), 3.46–3.74 (m, 2 H, CHN), 4.48–4.80
(m, 4 H, OCH), 8.47 [s, 2 H, NHC(S)] ppm. 31P{1H} NMR
(CDCl3): d 2.7 ppm. IR: n~ 1000 (POC), 1208 (PQO), 1564
(SCN), 3192 (NH) cmꢀ1. EI-MS: m/z (%) 701 (2) [M]+.
C26H52N4O6P2S2Ni (700.22): calc. C 44.52, H 7.47, N 7.99;
found: C 44.16, H 7.24, N 7.59%.
Infrared spectra (Nujol) were recorded with a Specord M-80
spectrometer in the range 400–3600 cmꢀ1. NMR spectra were
obtained on a Varian Unity-300 NMR spectrometer at 25 1C.
1H and 31P{1H} NMR spectra were recorded at 299.948 and
121.420 MHz, respectively. Chemical shifts are reported with
reference to SiMe4 (1H) and H3PO4 (31P{1H}). Electron ioni-
sation mass spectra were measured on a TRACE MS Finnigan
MAT instrument. The ionisation energy was 70 eV. The
substance was injected directly into the ion source at 150 1C.
Heating was carried out in a programmed mode from 35–
200 1C at a rate of 35 1C minꢀ1. Elemental analyses were
performed on a Perkin-Elmer 2400 CHN microanalyser.
[Pd(A5)2] and [Pd(B1,2)2]. A suspension of HA5 or HB1.2
(1.410, 1.480 or 1.550 g, respectively; 5 mmol) in aqueous
ethanol (20 mL) was mixed with an ethanol solution of
potassium hydroxide (0.280 g, 5 mmol). An acetonitrile
(20 mL) solution of [PdCl2(PhCN)2] (1.072 g, 2.8 mmol) was
added dropwise under vigorous stirring to the resulting
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potassium salt. The mixture was stirred at room temperature
for further 5 h and left overnight. The resulting complex was
extracted with dichloromethane, washed with water and dried
with anhydrous MgSO4. The solvent was then removed
in vacuo. A precipitate was isolated from dichloromethane
by n-hexane.
8.439(2), c = 16.951(3) A, b = 91.55(3)1, V = 1743.7(6) A3,
Z = 2, Dc = 1.427 g cmꢀ3, m(Mo-Ka) = 0.819 mmꢀ1
,
reflections: 12 428 collected, 4044 unique, Rint = 0.0950,
R1(all) = 0.0610, wR2(all) = 0.0996.
[Ni(A2)2]. C26H38Br2N4NiO6P2S2, Mr = 847.20 g molꢀ1
,
violet prisms, monoclinic, space group P21/c, a = 10.403(2),
b = 8.304(2), c = 20.958(6) A, b = 105.78(3)1, V = 1742.3(7)
[Pd(A5)2]. Yield (based on the ligand) 1.186 g (71%). Mp
116 1C. H NMR (CDCl3): d 1.22 (d, JH,H = 6.6 Hz, 12 H,
CH3, iPrN), 1.35 (d, JH,H = 6.1 Hz, 12 H, CH3, iPrO), 1.45
A3, Z = 2, Dc = 1.615 g cmꢀ3, m(Mo-Ka) = 3.105 mmꢀ1
,
reflections: 20 389 collected, 6626 unique, Rint = 0.1080,
1
3
3
(d, 3JH,H = 6.1 Hz, 12 H, CH3, iPrO), 4.01 (d sept, 3JHCNH
=
R1(all) = 0.0542, wR2(all) = 0.0894.
8.4 Hz, 3JH,H = 6.6 Hz, 2 H, NCH), 4.59 (d sept, 3JP,H = 6.4
Hz, 3JH,H = 6.1 Hz, 4 H, OCH), 8.55 [d, 3JHCNH = 8.4 Hz, 2
H, NHC(S)] ppm. 31P{1H} NMR (CDCl3): d 2.5 ppm. IR: n~
980 (POC), 1212 (PQO), 1560 (SCN), 3208 (NH) cmꢀ1. EI-
MS: m/z (%) 669 (4) [M]+. C20H44N4O6P2S2Pd (668.12): calc.
C 35.90, H 6.63, N 8.37; found: C 35.93, H 6.58, N 8.41%.
[Ni(A3)2]. C22H48N4NiO6P2S2, Mr = 649.40 g molꢀ1, violet
ꢀ
prisms, triclinic, space group P1 (no. 2), a = 9.273(2), b =
9.672(2), c = 21.274(4) A, a = 97.75(3), b = 91.62(3)1, g =
117.78(3)1, V = 1663.6(6) A3, Z = 2, Dc = 1.296 g cmꢀ3
,
m(Mo-Ka) = 0.843 mmꢀ1, reflections: 13 466 collected, 7453
unique, Rint = 0.0603, R1(all) = 0.0483, wR2(all) = 0.1114.
[Pd(B1)2]. Yield (based on the ligand) 0.818 g (47%). Mp
120 1C. 1H NMR (CDCl3): d 1.02–1.26 (m, 12 H, CH3, Et2N),
1.29–1.39 (m, 24 H, CH3, iPrO), 3.36–3.78 (m, 8 H, CH2,
Et2N), 4.58-4.76 (m, 4 H, OCH) ppm. 31P{1H} NMR (CDCl3):
[Pd(A5)2]. C20H44N4O6P2PdS2, Mr = 669.05 g molꢀ1, yel-
low prisms, monoclinic, space group P21/c, a = 18.981, b =
9.764, c = 16.498 A, b = 97.89(3)1, V = 3028.6(10) A3, Z =
4, Dc = 1.467 g cmꢀ3, m(Mo-Ka) = 0.895 mmꢀ1, reflections:
19 817 collected, 6927 unique, Rint = 0.0648, R1(all) = 0.0524,
wR2(all) = 0.0693.
d 9.4 ppm. IR: n~ 1004 (POC), 1140 (PQO), 1528 (SCN) cmꢀ1
.
EI-MS: m/z (%) 696 (2) [M]+. C22H48N4O6P2S2Pd (696.15):
calc. C 37.90, H 6.94, N 8.04; found: C 37.91, H 7.01, N
8.09%.
[Pd(B2)2]. C22H44N4O8P2PdS2, Mr = 725.07 g molꢀ1, red
prisms, monoclinic, space group P21/n, a = 18.747(4), b =
17.566(4), c = 19.950(4) A, b = 100.046(5)1, V = 6469(2) A3,
[Pd(B2)2]. Yield (based on the ligand) 0.941 g (52%). Mp
1
3
156 1C. H NMR (CDCl3): d 1.33 (d, JH,H = 6.1 Hz, 12 H,
CH3), 1.34 (d, JH,H = 6.1 Hz, 12 H, CH3), 3.62–3.95 (m, 16
Z = 8, Dc = 1.489 g cmꢀ3, m(Mo-Ka) = 0.849 mmꢀ1
,
3
3
3
reflections: 51 115 collected, 11 411 unique, Rint = 0.0962,
H, CH2), 4.67 (d sept, JP,H = 7.7 Hz, JH,H = 6.1 Hz, 4 H,
OCH) ppm. 31P{1H} NMR (CDCl3): d 9.9 ppm. IR: n~ 1006
(POC), 1155 (PQO), 1546 (SCN) cmꢀ1. EI-MS: m/z (%)-[M]+
not observed. C22H44N4O8P2S2Pd (724.11): calc. C 36.44, H
6.12, N 7.73; found: C 36.47, H 6.16, N 7.76%.
R1(all) = 0.0555, wR2(all) = 0.0959.
CCDC reference numbers 622814 ([Ni(A1)2]), 622815
([Ni(A2)2]), 622816 ([Ni(A3)2]), 622817 ([Pd(A5)2]) and
635 626 ([Pd(B2)2]), respectively.
X-Ray crystallography
For crystallographic data in CIF or other electronic format
see DOI: 10.1039/b702896b.
The data for [Ni(A1)2], [Ni(A2)2], [Ni(A3)2] and [Pd(A5)2], were
collected at ꢀ173 1C using a KM4CCD diffractometer and
graphite-monochromated Mo-Ka radiation generated from
Diffraction X-ray tube operated at 50 kV and 35 mA. The
images were indexed, integrated and scaled using the KUMA
data reduction package.15 The structure was solved by heavy
atom and direct method using SHELX9716 and refined by the
full-matrix least-squares method on all F2 data.17 Non-hydro-
gen atoms were included in the refinement, with anisotropic
displacement parameters: the atoms were positioned geo-
metrically and refined as riding model.
Acknowledgements
This work was supported by the joint program of CRDF and
the Russian Ministry of Education and Science (BHRE 2004
Y2-C-07-02); the joint program of DAAD ‘‘Michail-Lomono-
sov’’ and the Russian Ministry of Education and Science
(Forschungsstipendien 2006/2007) and partly by University
of Wroclaw.
X-Ray diffraction data for [Pd(B2)2] were collected on a
Bruker AXS diffractometer equipped with a rotating anode
generator and with Mo-Ka radiation. All raw data were
corrected for absorption using SADABS.18 The structure
solutions were found with SHELXS,19 and the refinement
was carried out with SHELXL17 using anisotropic thermal
parameters for all non-hydrogen atoms. Hydrogen atoms were
added to the structure model on calculated positions and were
refined as rigid atoms.
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