Nickel(II) complexes with N-aralkyliminodiacetic acids: Preparation, spectroscopic, structural and thermal characterization

Article abstract of DOI:10.1016/j.ica.2013.02.017

The reactions of N-aralkyl derivatives of iminodiacetic acid (H ₂Bnida, H₂Peida, H₂Ppida, o-H₂Cbida, Bn = benzyl, Pe = 2-phenylethyl, Pp = 3-phenylprop-1-yl, o-Cb = o-chlorobenzyl) with nickel(II) chloride hexahydrate or nickel(II) acetate tetrahydrate in aqueous solutions were studied. Five new nickel(II) complexes [Ni(Bnida)(H ₂O)₃]·H₂O (1), [Ni(Peida)(H ₂O)₃] (2), [Ni(Ppida)(H₂O)₃] ·H₂O (3a), [Ni(Ppida)(H₂O)₃] (3b) and [Ni(o-Cbida)(H₂O)₃] (4) were prepared and characterized by infrared spectroscopy and thermal analysis (TGA-DTA). The crystal structures of 1 and 3b were determined by single-crystal X-ray structural analysis. The octahedral coordination environment around the nickel(II) ion in 1 and 3b consists of an O,N,O′-tridentate N-aralkyliminodiacetate ion and three water molecules arranged in a fac-position. The molecules in the crystal structures of 1 and 3b are connected into a complicated hydrogen-bonded 2D network, dominated by the O-H?O hydrogen bonds. These 2D networks are in turn assembled into a 3D architecture only by weak van der Waals interactions.

Full text of DOI:10.1016/j.ica.2013.02.017

Inorganica Chimica Acta 400 (2013) 122–129
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Nickel(II) complexes with N-aralkyliminodiacetic acids: Preparation,
spectroscopic, structural and thermal characterization
⇑
⇑
´
ˇ
´
Neven Smrecki, Boris-Marko Kukovec , Marijana Ðakovic, Zora Popovic
University of Zagreb, Faculty of Science, Department of Chemistry, Laboratory of General and Inorganic Chemistry, Horvatovac 102a, 10 000 Zagreb, Croatia
a r t i c l e i n f o
a b s t r a c t
Article history:
The reactions of N-aralkyl derivatives of iminodiacetic acid (H2Bnida, H2Peida, H2Ppida, o-H2Cbida,
Bn = benzyl, Pe = 2-phenylethyl, Pp = 3-phenylprop-1-yl, o-Cb = o-chlorobenzyl) with nickel(II) chloride
hexahydrate or nickel(II) acetate tetrahydrate in aqueous solutions were studied. Five new nickel(II) com-
plexes [Ni(Bnida)(H2O)3]ꢀH2O (1), [Ni(Peida)(H2O)3] (2), [Ni(Ppida)(H2O)3]ꢀH2O (3a), [Ni(Ppida)(H2O)3]
(3b) and [Ni(o-Cbida)(H2O)3] (4) were prepared and characterized by infrared spectroscopy and thermal
analysis (TGA–DTA). The crystal structures of 1 and 3b were determined by single-crystal X-ray structural
analysis. The octahedral coordination environment around the nickel(II) ion in 1 and 3b consists of an
O,N,O0-tridentate N-aralkyliminodiacetate ion and three water molecules arranged in a fac-position.
The molecules in the crystal structures of 1 and 3b are connected into a complicated hydrogen-bonded
2D network, dominated by the O–Hꢀ ꢀ ꢀO hydrogen bonds. These 2D networks are in turn assembled into
a 3D architecture only by weak van der Waals interactions.
Received 5 November 2012
Received in revised form 10 February 2013
Accepted 13 February 2013
Available online 21 February 2013
Keywords:
Nickel(II)
Iminodiacetate
IR spectroscopy
Thermal analysis
X-ray structure determination
Ó 2013 Elsevier B.V. All rights reserved.
1. Introduction
determining the metal-oxygen dimensionality in hybrid systems
[4]. On the other hand, the study of ternary complexes, involving
The iminodiacetate ion (ida2ꢁ) is a tridentate chelating ligand
able to partially satisfy a metal ion coordination, enabling the for-
mation of a large variety of mixed-ligand metal complexes with
iminodiacetic acid (H2ida) or its derivatives (H2Rida; R = alkyl, aryl
or an aralkyl group). The available information strongly suggests
that the coordination ability of the H2Rida ligand can be affected
by the non-coordinating moiety R [1]. In the octahedral complexes
of divalent metals with the metal-to-ligand ratio of 1:1, the
tridentate ligands, based on iminodiacetic acid, occupy only three
coordination sites of the octahedron. The metal coordination can
be completed in different ways, by adding one or more extra
ligands or by polymerization [2]. Owing to the various coordina-
tion modes of the iminodiacetic acid ligands and the possibility
to control dissociation of the carboxylate groups by minor varia-
tion in the reaction conditions, the supramolecular structures of
the metal complexes can be achieved via hydrogen bonds [3].
The hybrid inorganic-organic compounds show considerable
promise as a class of porous materials with properties complemen-
tary to those seen in aluminosilicates. These materials illustrate
the role of higher reaction temperature in reducing the framework
water content and the importance of ligand flexibility in
transition metal ions and nucleobases or their derivatives, is a
very important topic because of their presence in the biological
systems [5].
Although nickel is an essential element for methanogenic bacte-
ria, its function in human organism is still unknown [6]. However,
the metal itself, as well as its alloys and compounds, are considered
or known to be human carcinogens [7]. Therefore, removing nick-
el(II) ions from the environment by complexation should lower the
risk from nickel poisoning [6]. Iminodiacetic acid, nitrilotriacetic
acid and other similar complexones are very effective for this pur-
pose because of the great stability of their metal complexes over a
wide pH range [8].
Phenethylamine behaves as a neuromodulator or neurotrans-
mitter in the mammalian central nervous system. Many substi-
tuted aralkylamines are known as stimulants, hallucinogens,
psychedelics and antidepressants. Since the aralkyl amines and
their derivatives exhibit psychoactive properties [9], the investiga-
tion of the N-aralkylated iminodiacetic acids and their metal com-
plexes is also of a pharmaceutical interest.
We prepared five new nickel(II) complexes with various
N-aralkyliminodiacetic acids: N-benzyliminodiacetic (H2Bnida),
N-(2-phenylethyl)iminodiacetic (H2Peida), N-(3-phenylprop-1-
yl)iminodiacetic (H2Ppida) and N-(o-chlorobenzyl)iminodiacetic
acid (o-H2Cbida) in order to get more insight into the coordination
chemistry of divalent transition metals with iminodiacetic acid
derivatives.
⇑
Corresponding authors. Tel.: +385
1
4606355; fax: +385
1 4606341
(B.-M. Kukovec), tel.: +385
1
4606354; fax: +385 1
4606341 (Z. Popovic´).
E-mail addresses: bkukovec@chem.pmf.hr (B.-M. Kukovec), zpopovic@
chem.pmf.hr (Z. Popovic´).
0020-1693/$ - see front matter Ó 2013 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.ica.2013.02.017

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
123
Various cobalt(II), nickel(II) and copper(II) complexes with
H2Bnida and its para-substituted derivatives were already described
in the literature and most of them contain heterocyclic nitrogen
bases (imidazole, pyridine and purine derivatives) or water
molecules as additional ligands, including [Ni(Bnida)(H2O)3],
which is a solvatomorph of our complex [Ni(Bnida)(H2O)3]ꢀH2O
(1) [10–15] (vide infra). There are also three nickel(II) complexes
with H2Bnida and its p-methyl or p-methoxy (p-X) derivatives,
which are salts of the type [Ni(imidazole)6][Ni(p-XBnida)2] [1] or
[Ni(H2O)4(imidazole)2][Ni(Bnida)2] [2]. As far as we know, no com-
plexes with H2Ppida were structurally described until now (see
Scheme 1).
ous sodium hydroxide solution (8.0 g; 0.2 mol in 40 mL). The alkali
was added at such a rate that the temperature of the reaction mix-
ture never reached 20 °C. Then, 11.0 mL (0.1 mol) of the pure (col-
orless) benzylamine was added [Note 1]. The reaction mixture was
refluxed and a solution of 8.0 g NaOH in 40 mL of water was added
dropwise into it during one hour period. The clear colorless solu-
tion was formed and the refluxing was continued for one addi-
tional hour. The reaction mixture was poured into a large beaker,
acidified to pHꢂ2 with 34.0 mL [Note 2] of diluted hydrochloric
acid (1:1 v/v) (CAUTION – white fumes are evolved!) and cooled
to the room temperature. The bottom of the beaker was scratched
with a sharp glass rod to induce the precipitation [Note 3] and stir-
red until the mixture solidified. After standing overnight in a
refrigerator, the product was filtered off by suction, washed with
150 mL of ice water and dried by standing in air for a few days.
Yield: 18.2 g (82%), m.p. 204.5 °C. White odorless powder, soluble
in dimethyl sulfoxide, formic acid, N,N-dimethylformamide and
hot water. Very soluble in alkaline aqueous solutions. Anal. Calc.
for C11H13NO4 (223.22): C, 59.18; H, 5.87; N, 6.28. Found: C,
57.86; H, 5.22; N, 6.42%. NMR data: 1H NMR (600 MHz, DMSO-
d6) d: 3.42 (s, 4H), 3.84 (s, 2H), 7.34 (m, 5H). 13C NMR (150 MHz,
DMSO-d6) d: 53.60 (CH2), 57.09 (CH2), 127.08 (CH), 128.18 (CH),
128.66 (CH), 138.57 (C), 172.18 (COOH). The assigned FTIR data
2. Experimental
2.1. Reagents and physical measurements
All chemicals for the syntheses were purchased from commer-
cial sources (Aldrich, Acros or Merck) and used as received without
further purification. The ligands were prepared by a modified
method [15]. The CHN analyses were performed on a Perkin-Elmer
2400 Series II CHNS analyzer in the Analytical Services Laboratories
-
´
of the Ruder Boškovic Institute, Zagreb, Croatia. The FTIR spectra
(cmꢁ1): 3025, 2972 (
broad), 1729 and 1714, 1248, 703 (
m
(CH)); 2700–2300 (
m
(NH+)); ꢃ3450 (m,
were obtained from KBr pellets in the range 4000–450 cmꢁ1 on a
Perkin-Elmer Spectrum RXI FTIR-spectrometer. The TGA–DTA
measurements were performed at a heating rate of 10 °C minꢁ1
in the temperature range 25–600 °C, under nitrogen or oxygen
flow of 20 mL minꢁ1 on an instrument Mettler-Toledo TGA–SDTA
851e. Approximately 10 mg of sample were placed in a standard
m
(OH),
m(C@O), d(OH) and
p
(OH) of COOH); 1651 and 1387 (mas and ms of COOꢁ). Other FTIR
data (cmꢁ1): 2850(m, br), 1586(m), 1564(m), 1498(m), 1457(m),
1428(s), 1361(s), 1315(m), 1215(s), 1194(s), 1121(m), 1085(m),
1052(m), 1021(m), 956(s), 947(m), 894(m), 878(s), 752(s),
669(w), 624(m), 576(m), 550(w), 529(m), 504(w), 486(w),
472(w), 459(w).
aluminum crucible (40 lL). The DSC measurements were per-
formed at heating rate of 10 °C minꢁ1 in the temperature range
25–500 °C, under nitrogen flow of 180 mL minꢁ1 on an instrument
Mettler-Toledo DSC 823e. Approximately 2–5 mg of sample were
Note 1. When technical (yellow) benzylamine is used in this
preparation, a pale pink product is obtained. The color of the prod-
uct may be removed by adding about 0.5 g of activated carbon to
the hot solution before acidification. After 5ꢁ10 min of boiling
and subsequent filtering, a colorless filtrate is obtained, providing
a white product with somewhat lower yield (about 70%).
Note 2. Further acidification must be avoided as it decreases the
yield. When 40 mL of hydrochloric acid were added, the yield was
only 62%.
Note 3. The product easily forms supersaturated aqueous solu-
tions which may remain for days if not disturbed by scratching.
If the sample of this compound is already available, it can be used
to initiate the precipitation which then starts more quickly and no
scratching is needed.
placed in the standard aluminum crucible (40
tra of the ligands were recorded in the NMR Centre of the Ruder
l
L). The NMR spec-
-
´
Boškovic Institute, Zagreb, Croatia on a Bruker AV 600 spectrome-
ter, operating at 600 MHz for the 1H nucleus and at 150 MHz for
the 13C nucleus. The samples were measured in DMSO-d6 solutions
at 298 K, using 5 mm NMR tubes. The chemical shifts in ppm were
referenced to TMS. The complexes are paramagnetic and, therefore,
not characterized by this method.
2.2. Preparation of the ligands
2.2.1. N-Benzyliminodiacetic acid, H2Bnida
An aqueous solution of chloroacetic acid (19.0 g; 0.2 mol in
70 mL) was cooled in ice bath to 5 °C and neutralized with an aque-
2.2.2. N-(2-Phenylethyl)iminodiacetic acid, H2Peida
This ligand was prepared in the same way as reported for
H2Bnida, but using phenethylamine (12.5 mL; 0.1 mol) instead of
benzylamine. After the acidification, the product precipitates spon-
taneously by cooling of the hot solution. Yield: 19.8 g (84%); m.p
181.4 °C. White odorless crystals, soluble in dimethyl sulfoxide,
N,N-dimethylformamide and hot water. Very soluble in alkaline
aqueous solutions. Anal. Calc. for C12H15NO4 (237.25): C, 60.75;
H, 6.37; N, 5.90. Found: C, 59.86; H, 6.22; N, 6.12%. NMR data: 1H
NMR (600 MHz, DMSO-d6) d: 2.73 (t, 2H), 2.89 (t, 2H), 3.49 (s,
4H), 7.21 (m, 5H). 13C NMR (150 MHz, DMSO-d6) d: 33.65 (CH2),
54.61 (CH2), 57.09 (CH2), 125.86 (CH), 128.20 (CH), 128.56 (CH),
139.84 (C), 172.32 (COOH). The assigned FTIR data (cmꢁ1): 3030,
Cl
N
COOH
N
COOH
COOH
COOH
o-H2Cbida
H2Bnida
COOH
COOH
2991, 2965 and 2840 (
broad), 1709, 1229 and 739 (
m
(CH)); 2700–2300 (
m
(NH+)); ꢃ3450 (m,
N
COOH
COOH
N
m(OH), m(C@O), d(OH) and p(OH) of
COOH); 1608 and 1384 (mas and ms of COOꢁ). Other FTIR data
(cmꢁ1): 2840(m), 2648(br,w), 1498(m), 1432(vs), 1347(s),
1325(m), 1292(m), 1196(br, vs), 1083(s), 1032(m), 944(s),
910(m), 895(s), 858(s), 803(w), 782(m), 724(s), 696(s), 600(w),
560(w), 518(w), 478(w).
H2Ppida
H2Peida
Scheme 1. Structural formulae of the ligands: N-benzyliminodiacetic (H2Bnida),
N-(o-chlorobenzyl)iminodiacetic (o-H2Cbida), N-(2-phenylethyl)iminodiacetic
(H2Peida) and N-(3-phenylprop-1-yl)iminodiacetic acid (H2Ppida).

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
124
2.2.3. N-(3-Phenylprop-1-yl)iminodiacetic acid, H2Ppida
after 10 min of further heating. The almost colorless filtrate was
acidified with 17.0 mL of diluted hydrochloric acid (1:1 v/v) to
pH ꢂ2 and left to cool spontaneously. After the crystallization be-
gan, the mixture was left to stand overnight in a refrigerator. The
product was filtered off by suction, washed with 100 mL of ice-cold
water and 25 mL of ice-cold ethanol. The crude product (9.0 g;
72%), which was contaminated with the unreacted amine, was
recrystallized as described for H2Ppida, with 60% recovery; hence
the total yield is 43%. m.p. 197.8 °C. White odorless needles, solu-
ble in dimethyl sulfoxide and boiling water (about 1 g/20 mL), al-
most insoluble in cold water. Soluble in alkaline aqueous
solutions. Anal. Calc. for C11H12NO4Cl (257.66): C, 51.27; H, 4.69;
N, 5.44. Found: C, 50.86; H, 5.12; N, 5.32%. NMR data: 1H NMR
(600 MHz, DMSO-d6) d: 3.46 (s, 4H), 3.96 (s, 2H), 7.40 (m, 5H).
13C NMR (150 MHz, DMSO-d6) d: 53.92 (CH2), 54.32 (CH2), 127.06
(CH), 128.56 (CH), 129.08 (CH), 130.52 (CH), 132.89 (C), 136.34 (C),
172.25 (COOH). The assigned FTIR data (cmꢁ1): 3078, 3008 and
The apparatus for this preparation consists of a hot plate mag-
netic stirrer and three-necked round bottom flask equipped with
a Liebig condenser, dropping funnel and a thermometer reaching
below the surface of the reaction mixture. An aqueous solution
of chloroacetic acid (9.5 g; 0.1 mol in 50 mL) was cooled in an ice
bath to 5 °C and neutralized with an aqueous sodium hydroxide
solution (4.0 g; 0.1 mol in 40 mL). The alkali was added at such a
rate that the temperature of the reaction mixture never reached
20 °C. Then, 7.2 mL (0.05 mol) of pure (colorless) 3-phenylprop-
1-ylamine and 10 mL of ethanol were added [Note 1]. The reaction
mixture was stirred and heated in a hot water bath until the tem-
perature of the mixture reached 70 °C and the mixture became yel-
lowish and turbid. Another solution of 4.0 g NaOH (0.1 mol) in
40 mL of water was added dropwise in a 2 h period, maintaining
the pH below 11 and the temperature around 75–80 °C. A second
portion of ethanol (10 mL) was added after the addition of the first
20 mL of alkali. Finally, the water bath was heated to boiling, the
reaction mixture treated with 0.1 g of activated carbon, stirred
and heated for 5 additional minutes and filtered. The colorless fil-
trate was treated with the additional 30 mL of ethanol and acidi-
fied with 17.0 mL of diluted hydrochloric acid (1:1 v/v) to pH ꢂ2.
After standing over night, the product crystallized as white nee-
dles. The ice-cooled crude product (9.5 g; 76%) [Note 2] was filtered
off by suction and washed with 50 mL of water and 100 mL of eth-
anol. To obtain a pure product, 5.0 g of the substance was dissolved
in 150 mL of boiling water and subsequently treated with 300 mL
of ethanol. After cooling to the room temperature, the bottom of
the flask was scratched with a sharp glass rod and the solution
was left to stand in the refrigerator for 2 days. The crystals were fil-
tered off by suction and washed with 50 mL of ice-cold ethanol.
The recovery was 4.0 g (80%), making the total yield of the pure
product 61%. m.p. 198.0 °C. White odorless needle-like crystals,
soluble in dimethyl sulfoxide and boiling water (about 1 g/
30 mL), almost insoluble in cold water. Soluble in alkaline aqueous
solutions. Anal. Calc. for C13H17NO4 (251.28): C, 62.13; H, 6.82; N,
5.58. Found: C, 61.86; H, 6.99; N, 5.42%. NMR data: 1H NMR
(600 MHz, DMSO-d6) d: 1.69 (m, 2H), 2.57 (t, 2H), 2.68 (t, 2H),
3.43 (s, 4H), 7.19 (m, 5H). 13C NMR (150 MHz, DMSO-d6) d: 29.06
(CH2), 32.59 (CH2), 53.58 (CH2), 54.92 (CH2), 125.58 (CH), 128.18
(CH), 128.20 (CH), 141.98 (C), 172.27 (COOH). The assigned FTIR
2966 (
m
(CH)); 2700–2300 (
m
(NH+)); ꢃ3430 (m, broad), 1685,
1265, 774 and 672 (
m
(OH), m(C@O), d(OH) and p(OH) of COOH);
1597 and 1413 (mas and ms of COO–). Other FTIR data (cmꢁ1):
1519(m), 1479(m), 1367(m), 1265(w), 1212(m), 1051(m),
1017(m), 952(m), 894(w), 857(m), 602(w), 548(w), 520(w),
495(w), 460(w).
2.3. Preparation of the complexes
2.3.1. [Ni(Bnida)(H2O)3]ꢀH2O (1)
0.23 g (1.0 mmol) of H2Bnida was added into a solution of 0.06 g
of KOH (1.1 mmol) in 25 mL of water. The mixture was heated until a
clear colorless solution was formed and then treated with a solution
of 0.12 g (0.5 mmol) NiCl2ꢀ6H2O in 20 mL of water. The resulting
blue-green solution (pH ꢂ5) was left to stand overnight. The blue
crystals of 1 were filtered off, washed with 5 mL of water and dried
in air. Yield: 0.13 g (74%). Soluble in hot pyridine, less soluble in di-
methyl sulfoxide or N,N-dimethylformamide, almost insoluble in
water. Anal. Calc. for C11H19NO8Ni (351.96): C, 37.50; H, 5.40; N,
4.00. Found: C, 37.02; H, 5.21; N, 3.91%. The assigned FTIR data
(cmꢁ1): ꢃ3450–2900 (s, broad) (
m(OH) of H2O); 1623 and 1410 (mas
and ms of COOꢁ). Other FTIR data (cmꢁ1): 1580(vs), 1496(m), 1458
(m), 1389(m), 1361(m), 1329(m), 1273(w), 1222(w), 1205(w),
1091(w), 1073(w), 973(w), 944(w), 921(m), 828(w), 765(m), 741
(m), 707(m), 669(w), 632(m), 584(w), 523(m), 496(w), 463(w).
After ꢂ4 weeks, blue prismatic crystals of 1 were obtained by
the slow evaporation of the filtrate.
data (cmꢁ1): 3017, 2954 and 2867 (
ꢃ3460 (m, broad), 1738, 1241 and 702 (
and
m
(CH)); 2700–2300 (
(OH), (C@O), d(OH)
m
(NH+));
m
m
p
(OH) of COOH); 1623 and 1409 (mas and ms of COOꢁ). Other
FTIR data (cmꢁ1): 4363(br, w), 1926(br, w), 1497(w), 1328(s),
1264(m), 1190(m), 1077(w), 1024(w), 982(m), 953(m), 916(w),
893(w), 855(w), 759(m), 719(m), 678(w), 613(w), 577(w),
513(w), 491(w).
2.3.2. [Ni(Peida)(H2O)3] (2)
An aqueous solution of nickel(II) acetate tetrahydrate (0.25 g;
1.0 mmol in 10 mL) was added to a boiling aqueous solution of
H2Peida (0.24 g; 1.0 mmol in 40 mL). The light green solution (pH ꢂ5)
became blue-green and light blue needles began to separate after
a few minutes. After the reaction mixture was left to stand over-
night, the product was filtered off by suction, washed with 15 mL
of water and dried in air. Yield: 0.30 g (86%). Soluble in dimethyl
sulfoxide and hot pyridine, less soluble in N,N-dimethylformamide,
almost insoluble in water. Anal. Calc. for C12H19NO7Ni (347.97): C,
41.42; H, 5.50; N, 4.03. Found: C, 41.04; H, 5.50; N, 4.12%. The as-
Note 1. The amine is not very soluble in water and forms white
emulsion with aqueous chloroacetate solution. The addition of eth-
anol increases the solubility of the amine in this medium.
Note 2. The crude product, which was contaminated with the
unreacted amine and possessed a strong aromatic odor, was not
satisfactory for the preparation of metal complexes.
2.2.4. N-(o-Chlorobenzyl)iminodiacetic acid, o-H2Cbida
This preparation was performed using the same apparatus as
described for H2Ppida, but with o-chlorobenzylamine (6.0 mL;
0.05 mol) instead of 3-phenylprop-1-ylamine. The reaction mix-
ture was heated to 70 °C and treated dropwise with another equiv-
signed FTIR data (cmꢁ1): 3587 (m), 3180 (s, broad) (
m(OH) of H2O);
1616 and 1411 (mas and ms of COOꢁ). Other FTIR data (cmꢁ1):
2965(m), 1576(s), 1497(m), 1469(m), 1454(m), 1435(m),
1375(m), 1347(m), 1306(w), 1249(w), 1209(w), 1109(m),
1070(w), 1031(w), 1010(w), 979(w), 967(w), 947(w), 913(m),
832(w), 772(m), 748(m), 694(m), 583(w), 535(w), 510(w).
alent of sodium hydroxide solution during
a 2.5 h period,
maintaining the pH below 11 and the temperature around 75–
80 °C. After the addition of the whole amount of the alkali, the
water bath was heated to boiling and the heating continued for
one additional hour. To remove the residual yellow oil, the reaction
mixture was treated with 0.2 g of activated carbon and filtered
2.3.3. [Ni(Ppida)(H2O)3]ꢀH2O (3a) and [Ni(Ppida)(H2O)3] (3b)
An aqueous solution of nickel(II) acetate tetrahydrate (0.25 g;
1.0 mmol in 10 mL) was added to a boiling aqueous solution of

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
125
H2Ppida (0.25 g; 1.0 mmol in 40 mL). The light green solution (pH
ꢂ5) became blue-green and pale blue needles began to separate
after three days of standing at room temperature. Next day the
product was filtered off by suction, washed with 15 mL of water
and dried in air to obtain 0.18 g of 3a (Yield: 47%). Soluble in di-
including anisotropic displacement parameters for all non-H
atoms.
The position of hydrogen atoms belonging to the carbon atoms
was geometrically optimized applying the riding model (0.97 Å,
Uiso(H) = 1.2Ueq(C) for methylen H atoms and 0.93 Å, Uiso(H) =
1.2Ueq(C) for aromatic H atoms). The hydrogen atoms belonging
to the water molecules were found in the difference Fourier maps.
The distance between the water molecule O atoms and the corre-
sponding hydrogen atoms was restrained to the average value of
0.82 Å using SHELXL-97 DFIX instruction. The isotropic Uiso(H) values
for these hydrogen atoms were fixed at the same time
(Uiso(H) = 1.2Ueq(O)).
methyl
sulfoxide
and
pyridine,
less
soluble
in
N,N-dimethylformamide, almost insoluble in water. The sample
loses its cocrystallized water after drying in a dessicator over
anhydrous CaCl2. Anal. Calc. for C13H23NO8Ni (380.01): C, 41.09;
H, 6.10; N, 3.69. Found: C, 41.43; H, 6.17; N, 3.85%. The assigned
FTIR data (cmꢁ1): 3385 (s, broad) (
(
m
(OH) of H2O); 1611 and 1412
mas and ms of COOꢁ). Other FTIR data (cmꢁ1): 1589(vs), 1496(w),
1470(w), 1440(w), 1382(m), 1338(w), 1316(w), 1246(w),
1109(w), 1051(w), 987(w), 969(w), 937(w), 904(w), 750(m),
727(w), 697(w), 575(w), 541(w), 490(w).
The affirmation of chosen space groups and the analysis of the
molecular geometry, hydrogen bonds and
p–p interactions were
performed by PLATON [19]. The molecular graphics were done with
After one additional day, blue crystals of 3b, suitable for X-ray
structural analysis, were obtained by the slow evaporation of the
light blue mother liquor, remained after filtration of 3a. The prod-
uct was filtered off, washed with 10 mL of water and dried in air.
Yield: 0.10 g (28%). Sparingly soluble in dimethyl sulfoxide and
pyridine, almost insoluble in N,N-dimethylformamide and water.
Anal. Calc. for C13H21NO7Ni (362.00): C, 43.09; H, 5.80; N, 3.78.
Found: C, 43.43; H, 5.94; N, 3.72%. The assigned FTIR data
ORTEP-3 [20] and MERCURY (Version 3.0) [21].
The crystal parameters, data collection and refinement results
for 1 and 3b are summarized in Table 1.
3. Results and discussion
3.1. Synthesis of the complexes
(cmꢁ1): 3562 (m), 3228 (s, broad) (
mas and ms of COOꢁ). Other FTIR data (cmꢁ1): 2963(m), 1582(vs),
m(OH) of H2O); 1613 and 1408
Complex 1 was prepared from nickel(II) chloride hexahydrate,
N-benzyliminodiacetic acid and potassium hydroxide in a slightly
acidic aqueous solution. Although the ligand-to-metal ratio was
2:1, the nickel(II) ion was found to be coordinated by only one li-
gand ion. The other possible complexes such as [Ni(HBnida)2] or
[Ni(HBnida)2(H2O)2], which could arise from this combination of
reactants, were never isolated. The coordination environment with
one fully deprotonated Bnida2ꢁ ion and three water molecules
(
1495(w), 1471(w), 1438(w), 1376(m), 1339(w), 1306(w),
1240(w), 1179(w), 1109(w), 1069(w), 966(w), 943(w), 913(w),
843(w), 749(m), 695(w), 628(w), 586(w), 515(w), 476(w).
2.3.4. Preparation of [Ni(o-Cbida)(H2O)3] (4)
An aqueous solution of nickel(II) acetate tetrahydrate (0.25 g;
1.0 mmol in 10 mL) was added to a boiling aqueous solution of
o-H2Cbida (0.26 g; 1.0 mmol in 40 mL). The light green solution
(pH 5) became blue-green and light blue needles began to separate
after about half an hour. After standing overnight, the product was
filtered off by suction, washed with 15 mL of water and dried in air.
Yield: 0.31 g (84%). Sparingly soluble in dimethyl sulfoxide and
pyridine, almost insoluble in N,N-dimethylformamide and water.
Anal. Calc. for C11H16NO7ClNi (368.39): C, 35.86; H, 4.38; N, 3.80.
Found: C, 35.86; H, 4.15; N, 4.03%. The assigned FTIR data
Table 1
Crystal data and details of the structure determination for 1 and 3b.
Compound
1
3b
Formula
C
11H19NiNO8
C13H21NiNO7
362.02
blue, block
monoclinic
P21/c
Mr
351.98
Color and habit
Crystal system
Space group
Crystal dimensions (mm3)
a (Å)
blue, prism
orthorhombic
Pca21
0.49 ꢄ 0.31 ꢄ 0.16 0.58 ꢄ 0.53 ꢄ 0.43
(cmꢁ1): 3292 (s, broad) (
m(OH) of H2O); 1595 and 1414 (mas and
11.3509(2)
16.7012(3)
7.4757(1)
90
18.1964(4)
7.7540(2)
11.2469(2)
90
102.004(2)
90
1552.18(6)
4
1.549
ms of COOꢁ). Other FTIR data (cmꢁ1): 2968(m), 1476(m), 1463(m),
1440(m), 1353(w), 1337(m), 1305(w), 1264(m), 1218(w),
1193(w), 1140(w), 1097(w), 1055(w), 1042(m), 974(w), 943(m),
921(m), 818(w), 782(s), 742(m), 725(m), 679(m), 629(w), 590(w),
546(w), 492(w).
b (Å)
c (Å)
a
(°)
b (°)
90
c
(°)
90
V (Å3)
1417.20(4)
4
1.650
Z
Dcalc (g cmꢁ3
)
l
(mm–1
)
1.408
1.283
760
2.4. Single crystal X-ray diffraction analysis and structure
determination
F(000)
736
h range (°)
h,k,l range
3.79–30.00
ꢁ15:15, ꢁ23:17,
ꢁ10:8
4.33–30.00
ꢁ25:21, ꢁ8:10,
ꢁ15:12
The suitable single crystals of 1 and 3b were selected and
mounted in air onto the thin glass fibers. The data collection for
1 and 3b was carried out by an Oxford Diffraction Xcalibur four-cir-
cle kappa geometry diffractometer with Xcalibur Sapphire 3 CCD
Scan type
x
,
u
x, u
8455
Number of measured reflections
Number of independent reflections 3802 (0.0201)
(Rint
Number of observed reflections
[I P 2 (I)]
Number of refined parameters
Ra, wRb [I P 2
(I)]
12162
4492 (0.0147)
)
detector, using a graphite monochromated Mo K
a (k = 0.71073 Å)
2933
3613
radiation, and by applying the CrysAlis Software system, Version
1.171.32.29 [16] for 1 and the CrysAlisPro Software system, Ver-
sion 1.171.33.55 [17] for 3b at room temperature (296(2) K). The
data reduction was done by the same programs [16–17].
r
214
217
r
0.0275, 0.0585
0.0410, 0.0613
0.923
0.0253, 0.0626
0.0347, 0.0644
0.975
R, wR (all data)
Goodness of fit (GOF) on F2, Sc
The X-ray diffraction data were corrected for Lorentz-polariza-
tion factor and scaled for absorption effects by multi-scan. The
structure of 1 was solved by direct methods and the structure of
3b by Patterson method, implemented in SHELXS-97 [18]. A refine-
ment procedure by full-matrix least squares methods, based on
F2 values against all reflections, was performed by SHELXL-97 [18],
Maximum, minimum electron
0.29, ꢁ0.20
0.33, ꢁ0.39
density (e Åꢁ3
)
Maximum
D
/
r
0.001
0.002
a
b
c
R =
wR = [
S =
R
||Fo| ꢁ |Fc||/
R|Fo|.
2
R
(Fo ꢁ Fc2)2/
R .
w(Fo2)2]1/2
2
R
[w(Fo ꢁ Fc2)2/(Nobs ꢁ Nparam)]1/2
.

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
126
which was observed in the case of 1 seems to be much more favor-
able for Ni(II) than the alternative arrangements with two partially
deprotonated HBnidaꢁ ions. This method of preparation was not
satisfactory for the complexes 2-4 because of the low solubility
of the higher analogues of H2Bnida. The second equivalent of the
ligand (H2Peida, H2Ppida or o-H2Cbida), which was used to main-
tain the reaction mixture acidic (to prevent the precipitation of
nickel(II)), crystallized out together with its nickel(II) complex,
forming the mixtures which could not be easily resolved. That
problem was avoided by the use of nickel(II) acetate and only
one equivalent of the ligand. This method also gave complex 1
by the reaction of nickel(II) acetate with H2Bnida. The formation
of these complexes was most probably assisted by their low solu-
bility, which allowed these reactions to proceed in a high yield.
ion in the spectra of H2Bnida (1651 cmꢁ1), H2Peida (1608 cmꢁ1),
H2Ppida (1623 cmꢁ1) and o-H2Cbida (1597 cmꢁ1) are shifted to
the lower wavenumbers in the spectra of 1, 3a, 3b and 4, but to
the higher wavenumber in the spectrum of 2. The bands assigned
to the symmetric stretching of the carboxylate ion (ms), observed
at 1387 cmꢁ1 (H2Bnida), 1384 cmꢁ1 (H2Peida), 1409 cmꢁ1
(H2Ppida) and 1413 cmꢁ1 (o-H2Cbida), are shifted to the higher
value in the spectra of these complexes. The stretching of the
carbonyl group,
m(C@O), which appears in the spectra of
H2Bnida (1729 and 1714 cmꢁ1), H2Peida (1709 cmꢁ1), H2Ppida
(1738 cmꢁ1) and o-H2Cbida (1685 cm-1), is absent in the spectra
of the complexes due to deprotonation of the both carboxylic
groups [22].
Complexes 1–4 exhibit similar solid-state infrared spectra. The
infrared spectrum of 1 shows
at 1410 cmꢁ1. Similar peaks of
observed in this region for complexes 2 (1616, 1411 cmꢁ1), 3a
m
as(COO) at 1623 cmꢁ1 and
m
s(COO)
m
as(COO) and ms(COO) are also
3.2. Infrared spectroscopy
(1611, 1412 cmꢁ1), 3b (1613, 1408 cmꢁ1
)
and
4
(1595,
s(COO),
The infrared spectra of the ligands indicate that these com-
pounds in the solid state exist in the zwitterionic form with one
deprotonated and one protonated carboxylic group [22]. The bands
1414 cmꢁ1). The difference between
as(COO) and
m
m
D
value, is greater than 200 cmꢁ1 for complexes 1, 2 and 3b and
is negligibly smaller than 200 cmꢁ1 for complex 3a (199 cmꢁ1),
assigned to the antisymmetric stretching (mas) of the carboxylate
Fig. 1. ORTEP-3 drawings of [Ni(Bnida)(H2O)3]ꢀH2O (1) (a) and [Ni(Ppida)(H2O)3] (3b) (b) with the atomic numbering scheme of the asymmetric unit. The thermal ellipsoids
are drawn at the 50% probability level at 296(2) K.

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
127
Fig. 2. The packing diagram of [Ni(Bnida)(H2O)3]ꢀH2O (1) (a view in the (100) plane). In this projection, the 2D network (described in Crystal structures section) is
represented as an endless double chain, extending in the [001] direction. The [Ni(Bnida)(H2O)3] and co-crystallized water molecules are connected into the chain by
intermolecular O–Hꢀ ꢀ ꢀO hydrogen bonds (shown by the dotted lines).
Fig. 3. The packing diagram of [Ni(Ppida)(H2O)3] (3b) (a view in the (010) plane). In this projection, the 2D network (described in Crystal structures section) is represented as
an endless double chain, extending in the [001] direction. The molecules are connected into the chain by intermolecular O–Hꢀ ꢀ ꢀO hydrogen bonds (shown by the dotted
lines).
indicating the monodentate coordination of the carboxylate group
[23,24]. Complex 4 is an exception with
= 181 cmꢁ1, probably
because of the steric or electronic influence of the chlorine atom
attached to the aromatic ring in the ortho position. The broad
bands observed in the range of 2300–3500 cmꢁ1 indicate numer-
ous hydrogen bonds of the O–Hꢀ ꢀ ꢀO type.
the calculated value for the Bnida2ꢁ ion (62.8%). The residue at
600 °C amounts to 18.4%. The same experiment, when performed
in the oxygen atmosphere, also shows two partially overlapped
steps: 13.2% at 153.2 °C and 7.1% at 206.7 °C for the total loss of
four water molecules. Further heating leads to a very exothermic
decomposition of the sample. The mass loss at 404.9 °C equals
63.1%, leaving a black residue (16.7%) at 600 °C.
D
3.3. Thermal analysis (TGA–DTA, DSC)
Complex 2 decomposes in three steps. The sample loses its
water molecules in two overlapped consecutive steps: 6.7% at
138.9 °C and 8.3% at 180.6 °C, the sum of which corresponds to
the calculated value of 15.5% for the total loss of three water mol-
ecules. Further heating leads to the complete degradation of the
sample. The mass loss of 70.2% between 200 and 600 °C corre-
sponds to the calculated value for the Peida2ꢁ ion (67.6%). The res-
idue at 600 °C amounts to 14.8%. The sample of 2 decomposes also
in three steps in the oxygen atmosphere: 5.6% at 140.2 °C and 9.2%
at 186.7 °C for all three water molecules and a very exothermic
decomposition between 300 and 400 °C (67.0%; two peaks found
at 363.8 and 385.2 °C). The residue at 600 °C amounts to 18.1%.
Complex 3a loses its water molecules in three overlapped steps:
6.8% at 100.6 °C, 6.9% at 119.6 °C and 6.6% at 167.5 °C, the sum of
which corresponds to the calculated value of 18.9% for the total
loss of four water molecules. The mass loss of 64.7% at 380.4 °C
The free ligands, when heated in the nitrogen atmosphere, melt
with decomposition. The melting points, obtained from DSC
curves, are 204.5, 181.4, 198.0 and 197.8 °C for H2Bnida, H2Peida,
H2Ppida and o-H2Cbida. The decomposition of H2Bnida starts at
201.1 °C, yielding a black residue (15.1% of its initial mass). The
decomposition of H2Peida and H2Ppida starts at 182.3 and
198.6 °C, and no residue is obtained. o-H2Cbida decomposes above
197.9 °C, yielding a black residue (2.2%).
Complex 1, when heated in nitrogen, loses its water molecules
in two partially overlapped consecutive steps: 13.7% at 149.2 °C
and 6.7% at 196.0 °C, the sum of which corresponds to the
calculated value of 20.5% for the total loss of four water molecules.
Further heating leads to the complete degradation of the sample.
The mass loss of 61.2% between 200 and 600 °C corresponds to

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
128
Table 2
(14.7% calculated; 14.3% observed), the sample loses 62.3% of its
initial mass (69.4% calculated for the o-Cbida2ꢁ ion) between 200
and 600 °C (an endothermic peak at 397.2 °C observed), leaving a
black residue (23.3%). The decomposition of 4 in oxygen starts with
the loss of three water molecules at 149.5 °C (14.6% observed).
After further heating a very exothermic decomposition occurs.
The loss of 67.1% at 411.1 °C corresponds to 70.0%, calculated for
the molecule of o-H2Cbida. The residue at 600 °C amounts to 18.7%.
Selected bond distances (Å) and angles (°) for 1 and 3b.
1
3b
Bond distances
Ni1–O1
Ni1–O2
Ni1–O3
Ni1–O4
Ni1–O5
Ni1–N1
2.067(2)
2.038(2)
2.067(2)
2.041(2)
2.017(1)
2.130(2)
2.0415(9)
2.0578(9)
2.079(1)
2.0448(9)
2.0297(9)
2.122(1)
Bond angles
O5–Ni1–O2
O5–Ni1–O4
O2–Ni1–O4
O5–Ni1–O1
O2–Ni1–O1
O4–Ni1–O1
O5–Ni1–O3
O2–Ni1–O3
O4–Ni1–O3
O1–Ni1–O3
O5–Ni1–N1
O2–Ni1–N1
O4–Ni1–N1
O1–Ni1–N1
O3–Ni1–N1
3.4. Crystal structures
176.49(8)
90.70(8)
92.72(8)
90.42(7)
86.16(8)
178.87(9)
89.10(6)
91.80(7)
88.85(8)
91.35(8)
82.95(6)
96.65(6)
82.65(6)
97.31(6)
168.27(8)
175.59(4)
87.48(4)
88.18(4)
91.85(4)
92.43(4)
176.43(4)
89.25(4)
91.75(4)
92.53(4)
90.97(4)
83.53(4)
95.10(4)
82.42(4)
94.02(4)
171.34(4)
ORTEP-3 drawings of the molecular structures of 1 and 3b are
depicted in Fig. 1. The crystal structures of 1 and 3b are shown
in Figs. 2 and 3, respectively. The selected molecular geometry
parameters are listed in Table 2, and the hydrogen bond geometry
in Table 3.
Nickel(II) ion is octahedrally coordinated by three water mole-
cules (O1, O2 and O3 atoms) and by O,N,O0-tridentate Bnida2ꢁ (in
1) or Ppida2ꢁ ligand (in 3b), resulting with the formation of fac iso-
mer in both cases. Bnida2ꢁ and Ppida2ꢁ are coordinated to nicke-
l(II) ion via imino N1 and carboxylate O4 and O5 atoms, forming
two five-membered chelate rings (defined by Ni1/O4/C1/C2/N1
and Ni1/O5/C3/C4/N1 atoms) (Fig. 1). The dihedral angle between
these rings amounts to 82.7(1)° in 1 and to 87.88(5)° in 3b. The dis-
tortion of the octahedron is indicated by the bond angles around
the nickel(II) ion in 1 and 3b, involving cis and trans pairs of donor
atoms (Table 2). The distortion is also observed in the bite angles
\O4–Ni1–N1 (82.65(6)° for 1 and 82.42(4ꢀ) for 3b) and \O5–Ni1–
N1 (82.95(6)° for 1 and 83.53(4)° for 3b) (Table 2). There is a
cocrystallized water molecule (O8 atom) in the structure of 1.
The analogous bond distances and angles in 1 and 3b are com-
parable to each other (Table 2). The Ni–N and Ni–O bond distances
(N and O atoms from Bnida2ꢁ and Ppida2ꢁ) in 1 and 3b are in accor-
dance with the corresponding ones, reported in the literature for
nickel(II) complexes with N-aralkyl derivatives of iminodiacetic
acid [1–2,14]. Complexes 1 and 3b are closely related to the pub-
lished [Ni(p-XBnida)(H2O)3] (p-X = p-methyl or p-methoxy). All of
these complexes have analogous molecular structures, but some
of them contain different number of cocrystallized water mole-
cules [1,14].
corresponds to the calculated value for the Ppida2ꢁ ion (65.6%). The
residue at 600 °C amounts to 14.4%. The sample of 3a also decom-
poses in four steps in the oxygen atmosphere: mass losses of 6.5%
at 101.1 °C, 7.2% at 121.7 °C and 7.0% at 169.2 °C correspond to the
release of all four water molecules and are followed by a very exo-
thermic decomposition between 250 and 350 °C (62.2%; two peaks
found at 328.5 °C and 367.7 °C). The residue at 600 °C amounts to
17.5%.
Complex 3b loses its water molecules in two steps: 4.9% at
120.2 °C and 8.9% at 140.0 °C, which is in agreement with the cal-
culated value of 4.9% per one water molecule. Further heating (two
peaks observed at 252.6 °C and 381.3 °C) leads to the loss of the li-
gand (70.2% observed, 68.9% calculated for the Ppida2ꢁ ion). The
residue at 600 °C amounts to 16.0%. The decomposition of 3b in
oxygen starts with the loss of one water molecule at 119.8 °C
(4.8% observed). The other two water molecules (10.4% observed)
are lost between 120 and 250 °C (one weak endothermic peak at
252.5 °C observed). A further heating leads to a very exothermic
decomposition, in the range 250–400 °C (67.4%; two peaks found
at 337.0 and 395.1 °C). The residue at 600 °C amounts to 17.5%.
Complex 4 decomposes in only two steps in the nitrogen atmo-
sphere. After the loss of all three water molecules at 155.7 °C
There are numerous intermolecular O–Hꢀ ꢀ ꢀO hydrogen bonds in
the crystal structures of both 1 and 3b, formed between water mol-
ecule O atoms as proton donors and carboxylate O atoms as proton
acceptors (Table 3). Some water molecule O atoms also act as proton
acceptors in the structure of 1. The molecules of [Ni(Bnida)(H2O)3]
and cocrystallized water molecules in the crystal structure of 1
Table 3
Hydrogen bond geometry for 1 and 3b.
D–Hꢀ ꢀ ꢀA
d(D–H) (Å)
d(Hꢀ ꢀ ꢀA) (Å)
d(Dꢀ ꢀ ꢀA) (Å)
\(D–Hꢀ ꢀ ꢀA) (°)
Symmetry code on A
1
O1–H11ꢀ ꢀ ꢀO6
O1–H12ꢀ ꢀ ꢀO7
O2–H21ꢀ ꢀ ꢀO6
O2–H22ꢀ ꢀ ꢀO8
O3–H31ꢀ ꢀ ꢀO1
O3–H32ꢀ ꢀ ꢀO4
O8–H81ꢀ ꢀ ꢀO5
O8–H82ꢀ ꢀ ꢀO5
0.78(2)
0.82(2)
0.83(2)
0.83(2)
0.74(2)
0.79(2)
0.80(3)
0.78(4)
2.01(3)
1.93(2)
2.02(2)
1.79(2)
2.36(3)
2.08(2)
2.07(3)
2.05(3)
2.760(2)
2.748(2)
2.810(2)
2.610(3)
2.973(2)
2.858(2)
2.845(3)
2.808(3)
161(3)
178(2)
161(2)
171(3)
142(3)
169(2)
163(4)
165(3)
x, y, ꢁ1 + z
ꢁ1/2 ꢁ x, y, ꢁ1/2 + z
1/2 ꢁ x, y, ꢁ1/2 + z
–
ꢁx, 1 ꢁ y, 1/2 + z
ꢁx, 1 ꢁ y, ꢁ1/2 + z
ꢁx, 1 ꢁ y, ꢁ1/2 + z
1/2 + x, 1 ꢁ y, z
3b
O1–H11ꢀ ꢀ ꢀO4
O1–H12ꢀ ꢀ ꢀO5
O2–H21ꢀ ꢀ ꢀO7
O2–H22ꢀ ꢀ ꢀO6
O3–H31ꢀ ꢀ ꢀO7
O3–H32ꢀ ꢀ ꢀO7
0.81(1)
0.81(2)
0.76(2)
0.82(2)
0.83(2)
0.87(1)
1.93(1)
1.93(2)
2.04(2)
1.87(2)
2.09(2)
2.27(2)
2.738(1)
2.738(1)
2.787(1)
2.676(2)
2.909(2)
3.075(2)
175(2)
178(2)
170(2)
173(2)
168(2)
155(2)
x, 5/2 ꢁ y, ꢁ1/2 + z
1 ꢁ x, 2 ꢁ y, 1 ꢁ z
x, 1 + y, z
x, 5/2 ꢁ y, ꢁ1/2 + z
1 ꢁ x, 1/2 + y, 3/2 ꢁ z
x, 1 + y, z

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N. Smrecki et al. / Inorganica Chimica Acta 400 (2013) 122–129
129
are connected into a complicated hydrogen-bonded 2D network
which is parallel to the (010) plane. These 2D networks are in turn
assembled only by weak van der Waals interactions in the [010]
direction (Fig. 2). The molecules in the crystal structure of 3b are
also connected into the hydrogen-bonded 2D network, parallel to
the (100) plane. The 2D networks are in turn assembled by weak
van der Waals interactions in the [100] direction (Fig. 3).
http://www.ccdc.cam.ac.uk/data_request/cif. Supplementary data
associated with this article can be found, in the online version, at
http://dx.doi.org/10.1016/j.ica.2013.02.017.
References
[1] D.K. Patel, D. Choquesillo-Lazarte, J.M. González-Perez, A. Domínguez-Martín,
A. Matilla-Hernandez, A. Castiñeiras, J. Niclós-Gutiérrez, Polyhedron 29 (2010)
683.
[2] I.N. Polyakova, A.L. Poznyak, V.S. Sergienko, Crystallogr. Rep. 45 (2000) 762.
[3] J. Chakraborty, H. Mayer-Figge, W.S. Sheldrick, P. Banerjee, Polyhedron 24
(2005) 771.
[4] P.M. Forster, A.K. Cheetham, Microporous Mesoporous Mat. 73 (2004) 57.
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Castiñeiras, J. Niclós-Gutiérrez, J. Inorg. Biochem. 105 (2011) 1073.
[6] A. Sigel, H. Sigel, R.K.O. Sigel, Metal Ions in Life Sciences, vol. 2, Wiley,
Chichester, 2007.
There are p–p interactions between the phenyl rings defined by
atoms C8/C9/C10/C11/C12/C13 and C8i/C9i/C10i/C11i/C12i/C13i
[symmetry code (i): ꢁx, 2 ꢁ y, ꢁz; centroid-centroid distance
3.614(1) Å, the angle between the planes 0°; the perpendicular dis-
tance between the planes 3.333(1) Å; the slippage 1.396 Å] in the
structure of 3b.
[7] International Agency for Research on Cancer. Available from: <http://
www.iarc.fr/>.
4. Conclusions
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Lippincott Williams & Wilkins, Philadelphia, 2002.
Several nickel(II) complexes were prepared by the reactions of
nickel(II) salts with various N-aralkyliminodiacetic acids in
aqueous solutions. Their molecular structures were determined
by X-ray diffractometry. All these complexes are monomer (not
polymeric) compounds and have analogous molecular structures
with fac-conformation of the chelators. Some of them contain
cocrystallized water molecules.
Due to their insolubility in the aqueous medium, the formation
of these complexes could find its application in the removal of
nickel(II) ions from water contaminated with the soluble nickel(II)
salts.
Metal complexes with N-(2-phenylethyl)iminodiacetic acid (H2-
Peida), are scarce in the literature, as only three metal complexes of
this ligand are known [15,25]. Complex 3b is the first prepared and
structurally characterized metal complex with N-(3-phenylprop-1-
yl)iminodiacetic acid (H2Ppida), a new ligand for the complexation
of metal ions.
[10] P.X. Rojas-González, A. Castiñeiras, J.M. González-Perez, D. Choquesillo-
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[13] D. Choquesillo-Lazarte, A. Domínguez-Martín, A. Matilla-Hernandez, C.S. de
Medina-Revilla, J.M. González-Perez, A. Castiñeiras, J. Niclós-Gutiérrez,
Polyhedron 29 (2010) 170.
[14] D.K. Patel, D. Choquesillo-Lazarte, A. Domínguez-Martín, M.P. Brandi-Blanco,
J.M. González-Perez, A. Castiñeiras, J. Niclós-Gutiérrez, Inorg. Chem. 50 (2011)
10549.
[15] E. Bugella-Altamirano, D. Choquesillo-Lazarte, J.M. González-Perez, M.J.
Sánchez-Moreno, R. Marín-Sánchez, J.D. Martín-Ramos, B. Covelo, R.
Carballo, A. Castiñeiras, J. Niclós-Gutiérrez, Inorg. Chim. Acta 339 (2002) 160.
[16] Oxford Diffraction CrysAlis CCD and CrysAlis RED, Version 1.171.32.29, Oxford
Diffraction Ltd., Abingdon, Oxfordshire, England, 2008.
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[18] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112.
[19] A.L. Spek, J. Appl. Crystallogr. 36 (2003) 7.
Acknowledgements
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This research was supported by the Ministry of Science,
Education and Sports of the Republic of Croatia (Grant No.
119-1193079-1332). The authors are grateful to Dr. Marijana
[21] C.F. Macrae, I.J. Bruno, J.A. Chisholm, P.R. Edgington, P. McCabe, E. Pidcock, L.
Rodriguez-Monge, R. Taylor, J. van de Streek, P.A. Wood, J. Appl. Crystallogr. 41
(2008) 466.
[22] R.M. Silverstein, F.X. Webster, D. Kiemle, Spectrometric Identification of
Organic Compounds, seventh ed., Wiley, New York, 2005.
[23] G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. 33 (1980) 227.
[24] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination
Compounds, part B, sixth ed., Wiley, Hoboken, 2009.
´
Vinkovic for the recorded NMR spectra.
Appendix A. Supplementary material
[25] D. Choquesillo-Lazarte, M.J. Sánchez-Moreno, E. Bugella-Altamirano, M.J.
Moyano-Gallego, J.D. Martín-Ramos, J.M. González-Perez, R. Carballo, J.
Niclós-Gutiérrez, Z. Anorg. Allg. Chem. 629 (2003) 291.
CCDC 907170 and 907171 contain the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via