The influence of an intramolecular hydrogen bond on the 1,3-N,S-coordination of crown ether-containing N-phosphorylthiourea with Ni II

Article abstract of DOI:10.1039/b9nj00252a

Reaction of the lithium salt of N-phosphorylated thiourea [4′-benzo-15-crown-5]NHC(S)NHP(O)(OiPr)₂ (HL^I) with Ni^II leads to the chelate complex [NiL^I₂]. The metal center is found in a square-planar N<

Full text of DOI:10.1039/b9nj00252a

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The influence of an intramolecular hydrogen bond on the 1,3-N,S-
coordination of crown ether-containing N-phosphorylthiourea with NiIIw
Damir A. Safin,*a Maria G. Babashkina,a Axel Klein,a Felix D. Sokolov,b
Sergey V. Baranov,b Tania Pape,c F. Ekkehardt Hahnc and Dmitriy B. Krivolapovd
Received (in Victoria, Australia) 10th June 2009, Accepted 30th August 2009
First published as an Advance Article on the web 1st October 2009
DOI: 10.1039/b9nj00252a
Reaction of the lithium salt of N-phosphorylated thiourea [40-benzo-15-crown-5]-
NHC(S)NHP(O)(OiPr)2 (HLI) with NiII leads to the chelate complex [NiLI2]. 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 LI ligands. Reaction of [NiLI2] and its non-crown
ether-containing analog Ni[PhNHC(S)NP(O)(OiPr)2]2 ([NiLII2]) with 2,20-bipyridine (bipy) and
1,10-phenanthroline (phen) leads to the [Ni(bipy)LI,II2] and [Ni(phen)LI,II2] heteroligand complexes.
The coordination mode is preserved for the phosphorus-containing ligands. The extraction
properties of the crown ether-containing compounds towards alkali metal picrates were
investigated. The molecular structures of HLI, [NiLI2] and [Ni(bipy)LII2] were elucidated
by X-ray diffraction.
1,5-S,X-chelate formation. However, these investigations showed
Introduction
that ligands of the general formula RNHC(S)NHP(O)(OiPr)2
form 1,3-N,S-chelates with NiII and PdII cations.22–24 The
The metal–organic architectures formed by d-metal cations
and bifunctional ligands, e.g. bis-b-diketonates or bis-N-
higher stability of the 1,3-N,S- relative to the 1,5-O,S-isomer
acylthioureas),1–6 are of great interest due to their magnetic,
is caused by (i) a higher crystal field stabilization energy for the
low-spin d8 [M{RN(H)C(S)NP(O)(OiPr)2-N,S}2] complexes
gas storage or catalytic properties. In relation to this, the idea
and (ii) the formation of strong (20–25 kJ molꢀ1 22
intra-
)
of using crown ethers armed with exocyclic chelating groups as
ligands for the building of such structures seems rather
attractive.
molecular NHꢁ ꢁ ꢁOQP hydrogen bonds in the 1,3-N,S-chelate
complexes.
The combination of a crown ether moiety and exocyclic
donor groups in a molecule is an effective way to design
selective complexing agents.7–10 Metal-containing derivatives
of crown ethers are used as molecule-based ion probes,3,11,12
and as agents for molecular recognition and the transportation
of anions and ion pairs.13,14
It was interesting to use the coordination isomery of these
compounds for the creation of a new versatile building block
for the binding of crown ether moieties. Here, we report
the first example of the 1,3-N,S-coordination of crown ether-
containing N-diisopropoxyphosphinyl-N0-(benzo-15-crown-5)-
40-yl-thiourea (HLI)21 towards NiII.
The derivatives of various crown ethers bearing one or two
thioacylamidophosphate fragments, –C(S)NHP(X)(OR)2
(X = O, S), their complexes with CoII, NiII, PdII, CuI and
CdII cations,15–20 and the selective binding of sodium cations21
were reported previously by us. Ligands containing two
essentially different complexing moieties, such as a chelating
fragment and a macrocycle, possess the ability to form complexes
with both alkaline and transition metal cations.
Results and discussion
N-Phosphorylated thiourea HLI, its non-crown ether-containing
analog PhNHC(S)NHP(O)(OiPr)2 (HLII
) and complex
2
[NiLII2] were prepared according to previously described
methods.21,24 Complex [NiLI2] was prepared by the following
procedure: the ligand was converted into its lithium salt and
subsequently reacted with Ni(NO3)2 in aqueous EtOH
(Scheme 1). The reaction of [NiLI,II2] with 2,20-bipyridine
(bipy) and 1,10-phenanthroline (phen) in benzene lead to the
formation of the heteroligand complexes [Ni(bipy)LI,II2] and
[Ni(phen)LI,II2] (Scheme 2).
The numerous examples reported by our group15–20 indicate
that the RC(S)NHP(X)R0 fragment has a propensity for
2
a Institut fur Anorganische Chemie, Universita¨t zu Ko¨ln,
¨
Greinstraße 6, D-50939 Koln, Germany. E-mail: damir.safin@ksu.ru;
¨
Fax: +49 221 4705196; Tel: +49 221 4702913
b A. M. Butlerov Chemistry Institute, Kazan State University,
Kremlevskaya Str. 18, Kazan, 420008, Russian Federation
c Institut fur Anorganische und Analytische Chemie, Westfalische
The compounds obtained were crystalline solids that were
soluble in most polar solvents and insoluble in n-hexane.
The IR spectrum of [NiLI2] is typical of 1,3-N,S-chelate
complexes of N-phosphoryl thioureas.22,23 The band for the
PQO group of the anionic ligand LI is shifted by 16 cmꢀ1 to
lower frequencies relative to the band of the parent ligand
(nPQO 1250 cmꢀ1 for HLI).21 Thus, the frequency observed for
the phosphoryl group band testifies to the absence of
¨
¨
Wilhelms-Universitat Munster, Corrensstraße 36, D-48149 Munster,
Germany
¨
¨
¨
d Arbusov Institute of Organic and Physical Chemistry, Arbuzov Str. 8,
Kazan, 420088, Russian Federation
w CCDC reference numbers 732320 (HLI), 732346 ([NiLI2]) and
735416 ([Ni(bipy)LII2]). For crystallographic data in CIF or other
electronic format see DOI: 10.1039/b9nj00252a
ꢂc
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In the 1H NMR spectra of [NiLI2], [Ni(bipy)LI,II2] and
[Ni(phen)LI,II2], a pair of signals is observed for the iPrO
protons. The signals for the methyl protons are observed at
1.03–1.65 ppm and the signals at 4.49–4.81 ppm correspond to
the OCH protons. The C6H3, C6H5 and polyaromatic proton
signals are observed at 6.76–8.80 ppm. The signals for the
CH2 protons of the crown ether fragment are in the range
3.57–4.37 ppm.
Only one NH proton signal is observed in the 1H NMR
spectra of [NiLI2], [Ni(bipy)LI,II2] and [Ni(phen)LI,II2]. The
influence of the intramolecular hydrogen bond, in combination
with deshielding effect of the aromatic group, result in a shift
of this signal to 9.37–10.37 ppm.
Crystals of HLI, [NiLI2] and [Ni(bipy)LII2] were obtained
by slow evaporation of their corresponding solutions of a
dichloromethane–n-hexane mixture, v/v 1 : 5 (Table 1).
The bond lengths in the N-thioacylamidophosphate moiety
of HLI are typical of N-phosphorylated thioureas and
thioamides (Table 2).20 The molecule in the crystal has a
syn-orientation of the C1–S1 and C2–N2 bonds, and an
anti-orientation of the C1–S1 and N1–P1 bonds (Fig. 1).
The C1–S1 and P1–O1 bonds are in an anti-orientation. Such
an arrangement is apparently caused by the formation of
intramolecular N2–H2dꢁꢁꢁO1 hydrogen bridges and additional
intermolecular N1–H1ꢁ ꢁ ꢁO1_a bonds (Table 3). Also, as a
result of the intermolecular interactions, a polymeric chain is
formed (Fig. 2).
Scheme 1 The preparation of [NiLI2].
Complex [NiLI2] (Fig. 3) is centrosymmetric. The NiII ion
lies on a two-fold axis and is coordinated in a square-planar
fashion, with the ligands arranged in a trans-configuration.
The four-membered Ni–S–C–N metallocycles are flat. The
endocyclic N–Ni–S angles in the four-membered rings fall in
the range 74–751. Inspection of the CQS and P–N bond
lengths, and a comparison with those found in the parent
ligand HLI, indicate that these are best described as single
bonds, while the PQO distance indicates the presence of a
double bond (Table 2).20,22–25
Scheme 2 The preparation of [Ni(bipy)LI,II2] and [Ni(phen)LI,II2].
R = 40-Benzo-15-crown-5, Ph. R0 = OiPr.
coordination with the central ion.23 A band at 3180 cmꢀ1 is
observed for the NH group in the IR spectrum of [NiLI2] that
is within the characteristic range for amide protons participating
in hydrogen bonds.20,22,23 There is a band at 1556 cmꢀ1
corresponding to the conjugated SCN fragment. Besides a
very strong band for the POC group at 1016 cmꢀ1, there is a
The ArNH protons are engaged in intramolecular hydrogen
bonds of the ArN–Hꢁ ꢁ ꢁOQP type. Due to their formation, a
flat syn,syn-conformation of the N–C–N–P–O unit is favored
(Fig. 3) A similar pattern was also observed for [NiLII2].24
An important feature of 1,3-N,S-chelate complexes in com-
parison with their 1,5-O,S- analogs is the ability to form
intermolecular hydrogen bonds (Table 3), leading to polymeric
chains (Fig. 4), and, in case of ligand LI, to a close arrangement
of the macrocyclic moieties in the crystal of [NiLI2].
The distances between the opposite oxygen atoms are in the
range 4.1–4.5 A. This effect can be used for the creation of
crystals with advanced set properties (e.g., in the design of ion
channels).
It is noteworthy that in the crystals of both HLI and [NiLI2],
the crown ether moieties stack on top of each other;
furthermore, the next-nearest molecules form two channels.
The distances between two crown ether moieties within a
channel corresponds to ca. 9.9 (the length of the c-axis)
and 10.5 (the length of the a-axis) A in HLI and [NiLI2],
respectively. This phenomenon is not observed frequently.
Similar stacked crown ether-containing compounds have been
described by Fromm et al.26–29
band for the COC group at 1135 cmꢀ1
.
The IR spectra of [Ni(bipy)LI,II2] and [Ni(phen)LI,II2] are
similar. The bands for the PQO and NH groups are at
1200–1237 and 3135–3160 cmꢀ1, respectively, and essentially
at the same values as those observed for the parent complexes
[NiLI,II2] (nPQO 1196 and nNH 3152 cmꢀ1 for [NiLII2]).24 This
testifies to the conservation of the coordination mode of the
phosphorus-containing ligands. The band at 1532–1562 cmꢀ1
corresponds to the conjugated SCN fragment. The band for
the POC group is observed at 998–1015 cmꢀ1. Besides
these bands, a characteristic band for the COC group at
1114–1129 cmꢀ1 testifies to the preservation of the crown
ethers in [Ni(bipy)LI2] and [Ni(phen)LI2].
The 31P{1H} NMR spectra of [Ni(bipy)LI,II
]
and
2
[Ni(phen)LI,II2] contain a signal at 2.0–2.5 ppm, slightly
down-field-shifted relative to the parent complexes [NiLI,II
(dP 1.7 ppm for [NiLII2]).24
]
2
ꢂc
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Table 1 Crystal data and data collection details for HLI, [NiLI2] and [Ni(bipy)LII2]w
HLI
[NiLI2]
[Ni(bipy)LII
]
2
Empirical formula
Formula weight
Crystal system
Space group
a/A
C21H35N2O8PS
506.54
Monoclinic
Cc
31.721(19)
8.715(5)
9.919(6)
106.486(7)
2629(3)
4
1.280
296
1080
0.229
7658
4826
3430
C42H68N4NiO16P2S2
1069.77
Monoclinic
C2/c
10.4922(15)
15.482(3)
32.203(6)
93.214(13)
5222.8(16)
4
1.360
293
2264
0.580
5562
5266
3106
C36H48N6NiO6P2S2
845.57
Orthorhombic
Fdd2
33.048(7)
27.265(5)
9.041(2)
—
8147(3)
8
1.379
153
3552
0.708
19710
4666
3853
b/A
c/A
b (1)
V/A3
Z
Dcalc/g cmꢀ3
T/K
F(000)
m/mmꢀ1
Reflections collected
Unique reflections
Observed reflections
Rint = 0.023
R1 = 0.0667
wR2 = 0.1885
0.23(12)
Rint = 0.027
R1 = 0.0502
wR2=0.1403
Rint = 0.097
R1 = 0.0416
wR2 = 0.0653
–0.005(11)
R indices (all data)
Flack parameter
Table 2 Selected bond lengths (A) and bond angles (1) for HLI, [NiLI–V2] and [Ni(bipy)LII
]
2
a,24
b,23
c,23
d,23
HLI
[NiLI2]
[NiLII
]
[NiLIII
]
2
[NiLIV
]
2
[NiLV
]
[Ni(bipy)LII
]
2
2
2
CQS
PQO
P–N
C–N(P)
C–N(C)
Ni–S
Ni–N
Ni–N
S–C–N(C)
S–C–N(P)
N–C–N
C–N–P
N–P–O
N–Ni–Sendo
Ni–S–C
1.673(5) 1.739(3)
1.459(4) 1.453(2)
1.647(5) 1.653(3)
1.386(7) 1.335(4)
1.310(6) 1.317(4)
1.732(3)
1.737(3)
1.713(4)
1.475(3)
1.466(3)
1.362(5)
1.335(5)
1.725(3)
1.482(2)
1.653(2)
1.342(4)
1.432(4)
1.716(3)
1.741(3)
1.476(2)
1.661(2)
1.354(4)
1.329(4)
1.705(3)
1.471(2)
1.647(3)
1.332(5)
1.330(5)
1.460(2)
1.645(3)
1.353(4)
1.313(4)
1.479(2)
1.635(2)
1.350(3)
1.346(3)
1.655(3)
1.342(5)
1.338(5)
2.2047(10) 2.2204(11) 2.2208(11) 2.2440(11)
2.2277(9)
2.2130(9) 2.2190(13) 2.4624(8)
LII
bipy
2.075(2)
1.903(2)
126.8(4) 124.2(2)
117.9(3) 108.2(2)
115.3(4) 127.6(3)
132.1(3) 127.1(2)
110.5(2) 111.36(14) 111.5(2)
74.59(8)
77.63(11)
1.906(3)
125.1(3)
108.5(2)
125.8(3)
126.8(3)
1.907(3)
125.5(3)
109.1(2)
126.0(3)
128.0(3)
113.2(2)
74.50(9)
77.43(13)
1.912(3)
125.7(3)
110.7(3)
123.6(4)
125.4(3)
108.3(2)
74.75(11)
76.81(14)
1.909(2)
125.3(2)
110.1(2)
124.6(3)
125.2(2)
112.82(13)
74.75(8)
76.84(11)
1.895(3)
128.0(2)
107.9(2)
123.7(3)
126.6(2)
111.5(2)
74.04(9)
1.896(2)
128.1(3)
108.4(2)
123.9(3)
128.0(2)
2.106(2)
126.0(2)
113.6(2)
120.5(2)
126.3(2)
112.43(13) 114.21(10)
75.19(9)
74.36(9)
77.21(13)
67.75(5)
78.33(9)
LII
77.34(11) 78.10(13)
bipy
Ni–N–Cendo
99.5(2)
99.3(2)
99.4(2)
97.8(3)
98.3(2)
99.1(2) 99.9(2)
100.26(15) 114.65(15)
a
b
c
d
HLII
tBuNHC(S)NP(O)(OiPr)2; data for two independent molecules.
=
PhNHC(S)NP(O)(OiPr)2. HLIII
=
p-MeOC6H4NHC(S)NP(O)(OiPr)2. HLIV
=
p-BrC6H4NHC(S)NP(O)(OiPr)2. HLV
=
Table 3 Hydrogen bond lengths (A) and angles (1) for HLI, [NiLI2]
and [Ni(bipy)LII
]
2
D–Hꢁ ꢁ ꢁA
D–H Hꢁ ꢁ ꢁA Dꢁ ꢁ ꢁA D–Hꢁ ꢁ ꢁA
HLIa
N1–H1ꢁ ꢁ ꢁO1_a#1 0.86 1.95
2.792(5) 166
2.732(6) 150
2.851(4) 132
2.847(3) 144
2.695(3) 149
3.228(3) 129
3.524(3) 133
3.226(3) 166
3.394(3) 123
2.955(3) 103
3.213(4) 128
N2–H2ꢁ ꢁ ꢁO1
N2–H2ꢁ ꢁ ꢁO1
0.86 1.96
0.86 2.20
[NiLI2]b
N2–H2ꢁ ꢁ ꢁO1_a#1 0.86 2.10
[Ni(bipy)LII
]
N2–H2ꢁ ꢁ ꢁO1
C7–H7ꢁ ꢁ ꢁS1
C9–H9ꢁ ꢁ ꢁS1#1
0.88 1.90
0.95 2.54
0.95 2.80
c
2
C11–H11ꢁ ꢁ ꢁO1#2 0.95 2.30
Fig. 1 A thermal ellipsoid representation of HLI (C = grey, N =
blue, O = red, P = orange, S = yellow). Ellipsoids are drawn at the
30% probability level. Hydrogen atoms are omitted for clarity.
C12–H12ꢁ ꢁ ꢁS1
C13–H13ꢁ ꢁ ꢁO1
0.95 2.78
1.00 2.57
C18–H18_aꢁ ꢁ ꢁO1 0.98 2.52
a
b
1
Symmetry code #1: x, 1 ꢀ y, ꢀ + z. Symmetry code #1: ꢀx, y,
According to the X-ray data, complex [Ni(bipy)LII
]
2
2
c
1
2
1
3
1
ꢀ z. Symmetry code #1: + x, ꢀ y, ꢀ + z; #2: x, y, ꢀ1 + z.
4
4
4
contains
a distorted trigonal-antiprismatic NiN4S2 core
(Fig. 5), the P–N and CQS bond lengths are shortened, and
the C–N(C) and PQO distances are lengthened (Table 2) in
comparison with the corresponding interatomic distances
reported for [NiLII2].24 The C–N(P) distances are essentially
similar in both complexes [NiLII2] and [Ni(bipy)LII2]. The Ni–S
ꢂc
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Fig. 2 The crystal packing of HLI (C = grey, H = white, N = blue,
O = red, P = orange, S = yellow). Hydrogen atoms not involved in
hydrogen bonding are omitted for clarity.
Fig. 5 A thermal ellipsoid representation of [Ni(bipy)LII2] (C = grey,
N = blue, Ni = green, O = red, P = orange, S = yellow). Ellipsoids
are drawn at the 30% probability level. Hydrogen atoms are omitted
for clarity.
There are intramolecular N–Hꢁ ꢁ ꢁOQP hydrogen bonds in
the crystal of [Ni(bipy)LII2] (Fig. 6, Table 3) that are formed
between the hydrogen atoms of the NH groups and the oxygen
atoms of the PQO groups of the anionic ligands. There are
also intermolecular C–Hꢁ ꢁ ꢁOQP and C–Hꢁ ꢁ ꢁSQC hydrogen
bonds (Fig. 6, Table 3). These bonds are formed between the
two hydrogen atoms of the bipyridine ligand of one molecule,
and the PQO oxygen atoms and CQS sulfur atoms of three
neighboring molecules, while the PQO oxygen atoms and the
CQS sulfur atoms of the same molecule also form hydrogen
bonds with the bipyridine hydrogen atoms of a further three
neighboring molecules (Fig. 6).
Thus, a 3D network of hydrogen bridges is found in the
crystal of [Ni(bipy)LII2], highlighting the importance of
hydrogen bonding for stabilizing the 1,3-N,S-isomer and
forming a supramolecular network in the crystal phase.
Compounds HLI, [NiLI2], [Ni(bipy)LI2] and [Ni(phen)LI2]
contain a set of active nucleophilic (crown ether and phosphoryl
group oxygen atoms) and electrophilic sites (tetracoordinated
NiII cation in [NiLI2]). This makes them interesting as new
building blocks for supramolecular structures.
Fig. 3 A thermal ellipsoid representation of [NiLI2] (C = grey, N =
blue, Ni = green, O = red, P = orange, S = yellow). Ellipsoids are
drawn at the 30% probability level. Hydrogen atoms are omitted for
clarity.
An investigation of the extraction properties of HLI,
[NiLI2], [Ni(bipy)LI2] and [Ni(phen)LI2] towards alkali metal
picrates, in comparison with 40-aminobenzo-15-crown-5 (1),
benzo-15-crown-5 (2) and 18-crown-6 (3), were performed
(Table 4). It is noteworthy that the extraction properties of
[NiLI2], [Ni(bipy)LI2] and [Ni(phen)LI2] did not depend on the
M+Picꢀ to crown ether-containing compound molar ratio.
Fig. 4 The crystal packing of [NiLI2] (C = grey, H = white, N =
blue, Ni = green, O = red, P = orange, S = yellow). H-atoms, not
involved in hydrogen bonding are omitted for clarity.
and Ni–N bond lengths for [Ni(bipy)LII2] are significantly
lengthened, and the N–Ni–Sendo angles are smaller compared
to the parent complex. This is due to the presence of the
additional donor ligand. The four-membered Ni–S–C–N
metallocycles are flat. The five-membered Ni–N–C–C–N
Fig. 6 The crystal packing of [Ni(bipy)LII2] (C = grey, H = white,
N = blue, Ni = green, O = red, P = orange, S = yellow). Hydrogen
atoms not involved in hydrogen bonding are omitted for clarity.
metallocycle is slightly distorted with
a torsion angle
N3–C8–C8_a–N3_a of ꢀ7.3(3)1.
ꢂc
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Table 4 The extraction properties of crown ether-containing com-
pounds HLI, [NiLI2], [Ni(bipy)LI2] and [Ni(phen)LI2] towards alkali
metal picrates (M+Picꢀ) in a CH2Cl2/H2O medium
[NiLII2]. This complex was prepared according to
previously described method.24
a
[NiLI2]. A suspension of HLI (0.253 g, 0.5 mmol) in aqueous
ethanol (35 mL) was mixed with an ethanolic solution of
lithium hydroxide (0.013 g, 0.55 mmol). An aqueous (20 mL)
solution of Ni(NO3)2ꢁ6H2O (0.087 g, 0.3 mmol) was added
dropwise with vigorous stirring. The reaction mixture was
stirred at room temperature for a further 5 h. Next, the
resulting complex was extracted using dichloromethane. The
combined extracts were washed with water and dried using
anhydrous MgSO4. The solvent was then removed under
vacuum. A precipitate was isolated by adding n-hexane to a
dichloromethane solution of the residue. Yield: 0.115 g (43%).
+
Li+
Na+
K+
NH4
HLI
1.0
14.9
12.3
37.2
[NiLI2]a
2.8/2.0
0.4/0.6
0.5/0.3
2.6
2.6
9.7
83.4/81.2
11.7/10.9
8.3/9.0
1.3
5.1
13.6
7.1/5.7
5.2/4.4
6.5/5.8
5.6
9.9
62.5
10.7/9.1
21.3/20.7
24.0/24.6
35.2
[Ni(bipy)LI2]a
[Ni(phen)LI2]a
1
2
3
24.2
61.3
M+Picꢀ to crown ether-containing compound molar ratio 1 : 1/2 : 1.
a
This indicates that both crown ethers of the molecules interact
with M+Picꢀ.
1
3
Mp. 179–180 1C. H NMR: 1.38 (d, JH,H = 5.4 Hz, 12 H,
CH3), 1.65 (d, JH,H = 5.4 Hz, 12 H, CH3), 3.63–4.25
3
From our experiments, it is evident that [NiLI2] expresses an
affinity towards the Na+ cation compared with parent ligand
HLI and crown ethers 1–3. Such dramatic selectivity changes
might be explained by the assistance of the donor centers of
the exocyclic chelate moieties and a change in the hydrophilic/
hydrophobic balance caused by the bulky organometallic
substituents. A decrease of the Na+ extraction capacity was
observed for [Ni(bipy)LI2] and [Ni(phen)LI2] compared to
[NiLI2], which might be due to steric hindrance. In contrast,
(m, 32 H, CH2, crown), 4.54–4.75 (m, 4 H, OCH), 6.76–7.03
(m, 6 H, C6H3) and 10.37 (s, 2 H, NH) ppm. 31P{1H} NMR:
1.9 ppm. IR: n 995 (POC), 1135 (COC), 1234 (PQO), 1515,
1556 (SCN) and 3168 (NH) cmꢀ1. C42H68N4NiO16P2S2
(1068.29): calc. C, 47.15; H, 6.41; N, 5.24. Found C, 47.33;
H, 6.43; N, 5.13%.
[Ni(bipy)LI,II2] and [Ni(phen)LI,II2]. A solution of complexes
[NiLI2] (0.107, 0.1 mmol) or [NiLII2] (0.069 g, 0.1 mmol) in
benzene (10 mL) was added dropwise to a stirred solution of
2,20-bipyridine (0.016 g, 0.1 mmol) or 1,10-phenanthroline
(0.018 g, 0.1 mmol) in benzene (10 mL). After complete
addition, the solution was stirred for one hour. The solvent
was then removed under vacuum. The residue was recrystallized
from a dichloromethane/n-hexane mixture.
the NH4 extraction increased going from [NiLI2] to hexa-
+
coordinated complexes, which could be explained by the
lability of the ammonium cation.
Conclusions
In summary, the data presented confirms that the formation of
intramolecular N–Hꢁ ꢁ ꢁOQP hydrogen bonds is a necessary
condition for 1,3-N,S-isomer stabilization in a square-planar
NiII complex with N-phosphorylated thiourea containing a
crown ether fragment. Conservation of the coordination mode
of deprotonated ligands LI,II was observed in heteroligand
complexes [Ni(bipy)LI,II2] and [Ni(phen)LI,II2].
The complex [NiLI2] showed an increase in Na+ extraction
capacity compared with the other crown ether-containing
complexes described above.
[Ni(bipy)LI2]. Yield: 0.103 g (84%). Mp. 128–131 1C.
1H NMR: 1.14–1.37 (m, 24 H, CH3), 3.57–4.08 (m, 32 H,
CH2, crown), 4.49–4.68 (m, 4 H, OCH), 6.81–8.74 (m, C6H3 +
bipy, overlapped with solvent signal) and 9.73 (s, 2 H, NH)
ppm. 31P{1H} NMR: 2.3 ppm. IR: n 1004 (POC), 1129 (COC),
1229 (PQO), 1547 (SCN) and 3160 (NH) cmꢀ1
.
C52H76N6NiO16P2S2 (1225.96): calc. C, 50.95; H, 6.25; N,
6.86. Found C, 50.82; H, 6.37; N, 6.71%.
[Ni(phen)LI2]. Yield: 0.114 g (91%). Mp. 143–144 1C. 1H
NMR: 1.03–1.28 (m, 24 H, CH3), 3.68–4.37 (m, 32 H, CH2,
crown), 4.59–4.81 (m, 4 H, OCH), 6.93–8.59 (m, C6H3
+
Experimental
phen, overlapped with solvent signal) and 9.59 (s, 2 H, NH)
ppm. 31P{1H} NMR: 2.5 ppm. IR: n 1015 (POC), 1114 (COC),
General procedures
1237 (PQO), 1532 (SCN) and 3152 (NH) cmꢀ1
.
Infrared spectra (Nujol) were recorded using a Specord M-80
spectrometer in the range 400–3600 cmꢀ1. NMR spectra were
obtained on a Bruker Avance 300 MHz spectrometer at 25 1C.
1H and 31P{1H} NMR spectra (CDCl3) were recorded at
299.948 and 121.420 MHz, respectively. Chemical shifts are
reported with reference to SiMe4 (1H) and H3PO4 (31P{1H}).
Electronic absorption spectra were recorded in the range
C54H76N6NiO16P2S2 (1249.99): calc. C, 51.89; H, 6.13; N,
6.72. Found C, 52.05; H, 6.26; N, 6.59%.
[Ni(bipy)LII2]. Yield: 0.079 g (94%). Mp. 130–132 1C. 1H
NMR: 1.21–1.48 (m, 24 H, CH3), 4.59–4.80 (m, 4 H, OCH),
7.28–8.80 (m, 18 H, Ph + bipy) and 9.52 (s, 2 H, NH) ppm.
31P{1H} NMR: 2.0 ppm. IR: n 1008 (POC), 1200 (PQO), 1562
(SCN) and 3135 (NH) cmꢀ1. C36H48N6NiO6P2S2 (845.57):
calc. C, 51.14; H, 5.72; N, 9.94. Found C, 51.03; H, 5.69; N,
10.02%.
250–400 nm on
a Perkin-Elmer Lambda 35 spectro-
photometer. Elemental analyses were performed on a CHNS
HEKAtech EuroEA 3000 analyzer.
Syntheses
1
[Ni(phen)LII2]. Yield: 0.076 g (87%). Mp. 164–166 1C. H
NMR: 1.15–1.36 (m, 24 H, CH3), 4.51–4.84 (m, 4 H, OCH),
HLI,II. N-Phosphorylated thioureas were prepared according
to previously described methods.21,24
7.19–8.74 (m, 18 H, Ph + phen) and 9.37 (s, 2 H, NH) ppm.
ꢂc
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009 New J. Chem., 2009, 33, 2443–2448 | 2447

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31P{1H} NMR: 2.4 ppm. IR: n 998 (POC), 1202 (PQO), 1540
(SCN) and 3142 (NH) cmꢀ1. C38H48N6NiO6P2S2 (869.59):
calc. C, 52.49; H, 5.56; N, 9.66. Found C, 52.64; H, 5.42;
N, 9.79%.
5 O. Hallale, S. A. Bourne and K. R. Koch, CrystEngComm, 2005,
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Picrate extraction experiment
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Single-species lithium, sodium, potassium or ammonium
picrate extraction was conducted with 3 mL of an aqueous
solution containing 100 mM of LiOH, NaOH, KOH or
NH4SCN and 0.07 mM of picric acid, and 3 mL of a 0.07 mM
CH2Cl2 solution of [NiLI2], [Ni(bipy)LI2], [Ni(phen)LI2], 1, 2 or
3. The resulting mixture was stirred for 5 h and left for a
further one hour for layer separation. The degree of extraction
was calculated from the difference of the absorption of the
initial cation picrate solution (l = 374 nm) and the separated
aqueous layer.
X-Ray crystallographyw
Data for HLI and [NiLI2] were collected on a Bruker SMART
Apex2 CCD diffractometer with graphite-monochromated
Mo-Ka radiation (l = 0.71073 A). The images were indexed,
integrated and scaled using the APEX2 data reduction
package.30 All raw data were corrected for absorption using
the SADABS31 program. The structures were solved by direct
methods using the SIR32 program and refinement was carried
out using SHELXL-9733 using anisotropic thermal parameters
for all non-hydrogen atoms. The hydrogen atoms were added
to the structure model in calculated positions and were refined
as rigid atoms. All calculations were performed on a personal
computer using the WinGX program.34
Diffraction data for [Ni(bipy)LII2] were collected on a
Bruker AXS APEX CCD diffractometer with graphite-
monochromated Mo-Ka radiation (l = 0.71073 A). Diffraction
data were collected over the full sphere and were corrected for
absorption. Data reduction was performed using the Bruker
SMART30 program package. Structure solutions were found
using the SHELXS-9733 package by the heavy atom method or
by direct methods, and were refined using SHELXL-9733
against |F2| using first isotropic and later anisotropic thermal
parameters for all non-hydrogen atoms. The hydrogen atoms
were added to the structure models in calculated positions.
The molecule resides on a two-fold axis.
17 N. G. Zabirov, V. V. Brusko, A. Y. Verat, D. B. Krivolapov,
I. A. Litvinov and R. A. Cherkasov, Polyhedron, 2004, 23, 2243.
18 D. A. Safin, M. G. Babashkina, F. D. Sokolov and N. G. Zabirov,
Inorg. Chem. Commun., 2006, 9, 1133.
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Acta, 2006, 359, 475.
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Curr. Org. Chem., 2006, 10, 27.
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1550.
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M. Kubiak, T. Pape, M. G. Babashkina, N. G. Zabirov,
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24 F. D. Sokolov, N. G. Zabirov, L. N. Yamalieva, V. G. Shtyrlin,
R. R. Garipov, V. V. Brusko, A. Yu. Verat, S. V. Baranov,
P. Mlynarz, T. Glowiak and H. Kozlowski, Inorg. Chim. Acta,
2006, 359, 2087.
25 F. H. Allen, O. Kennard, D. G. Watson, L. Brammer, A. G. Orpen
and R. Taylor, J. Chem. Soc., Perkin Trans. 2, 1987, S1.
26 M. Du"ak, R. Bergougnant, K. M. Fromm, H. R. Hagemann,
A. Y. Robin and T. A. Weso"owski, Spectrochim. Acta, Part A,
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27 K. M. Fromm, R. Bergougnant and A. Y. Robin, Z. Anorg. Allg.
Chem., 2006, 632, 828.
28 K. M. Fromm, E. D. Gueneau, H. Goesmann and C. G. Bochet, Z.
Anorg. Allg. Chem., 2003, 629, 597.
29 K. M. Fromm, E. D. Gueneau, J. P. Rivera and G. Bernardinelli,
Z. Anorg. Allg. Chem., 2002, 628, 171.
30 APEX2 Version 2.1, Bruker Advanced X-Ray Solutions, Bruker
AXS Inc., Madison, Wisconsin, USA, 2006; SAINTPlus: Data
reduction and correction program, version 7.31A, Bruker Advanced
X-Ray Solutions, Bruker AXS Inc., Madison, Wisconsin, USA,
2006.
Acknowledgements
This work was supported by the Russian Science Support
Foundation. D. A. S. and M. G. B. thank DAAD for
scholarships (Forschungsstipendien 2008/2009).
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This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2009
2448 | New J. Chem., 2009, 33, 2443–2448