Metal complexes with N-(trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands). Part I. Copper(II) chelates of p-3F, m-3F, and o-3F with or without imidazole-like ligands

Article abstract of DOI:10.1080/00958972.2015.1062092

(Figure Presented) Eight Cu(II) complexes with N-(p-, m- or o-trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands) have been synthesized to promote C-F/H interligand interactions involving the F₃C-group: {[Cu(μ₂-p-3F)(H

Full text of DOI:10.1080/00958972.2015.1062092

This article was downloaded by: [New York University]
On: 24 June 2015, At: 10:07
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer
House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Coordination Chemistry
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/gcoo20
Metal complexes with N-
(trifluoromethylbenzyl)iminodiacetate chelators
(x-3F ligands). Part I. Copper(II) chelates of p-3F,
m-3F and o-3F with or without imidazole-like ligands
Marina Serrano-Bracerasa, Duane Choquesillo-Lazarteb, Alicia Domínguez-Martínae, Ester
Vílchez-Rodrígueza, María Eugenia García-Rubiñoc, Josefa María González-Péreza, Alfonso
Castiñeirasd & Juan Niclós-Gutiérreza
a Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, 18071
Granada, Spain
b Laboratorio de Estudios Cristalográficos, IACT, CSIC-Universidad de Granada, Av. de las
Palmeras 4, E-18100 Armilla, Granada, Spain
c Department of Pharmaceutical and Organic Chemistry, Faculty of Pharmacy, University
Click for updates
of Granada, 18071 Granada, Spain
d Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de
Compostela, 15782 Santiago de Compostela, Spain
e Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057
Zurich, Switzerland
Accepted author version posted online: 24 Jun 2015.
To cite this article: Marina Serrano-Braceras, Duane Choquesillo-Lazarte, Alicia Domínguez-Martín, Ester Vílchez-
Rodríguez, María Eugenia García-Rubiño, Josefa María González-Pérez, Alfonso Castiñeiras & Juan Niclós-Gutiérrez
(2015): Metal complexes with N-(trifluoromethylbenzyl)iminodiacetate chelators (x-3F ligands). Part I. Copper(II)
chelates of p-3F, m-3F and o-3F with or without imidazole-like ligands, Journal of Coordination Chemistry, DOI:
10.1080/00958972.2015.1062092
To link to this article: http://dx.doi.org/10.1080/00958972.2015.1062092
Disclaimer: This is a version of an unedited manuscript that has been accepted for publication. As a service
to authors and researchers we are providing this version of the accepted manuscript (AM). Copyediting,
typesetting, and review of the resulting proof will be undertaken on this manuscript before final publication
of the Version of Record (VoR). During production and pre-press, errors may be discovered which could
affect the content, and all legal disclaimers that apply to the journal relate to this version also.
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of
the Content. Any opinions and views expressed in this publication are the opinions and views of the authors,
and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied
upon and should be independently verified with primary sources of information. Taylor and Francis shall
not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other
liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or
arising out of the use of the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any

form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Publisher: Taylor & Francis
Journal: Journal of Coordination Chemistry
DOI: http://dx.doi.org/10.1080/00958972.2015.1062092
Metal complexes with N-(trifluoromethylbenzyl)iminodiacetate chelators
(x-3F ligands). Part I. Copper(II) chelates of p-3F, m-3F and o-3F with or
without imidazole-like ligands
MARINA SERRANO-BRACERAS†, DUANE CHOQUESILLO-LAZARTE*‡,
ALICIA DOMÍNGUEZ-MARTÍN†¥, ESTER VÍLCHEZ-RODRÍGUEZ†,
MARÍA EUGENIA GARCÍA-RUBIÑO§, JOSEFA MARÍA GONZÁLEZ-PÉREZ†,
ALFONSO CASTIÑEIRAS¶ and JUAN NICLÓS-GUTIÉRREZ†
†Department of Inorganic Chemistry, Faculty of Pharmacy, University of Granada, 18071 Granada, Spain
‡Laboratorio de Estudios Cristalográficos, IACT, CSIC-Universidad de Granada, Av. de las Palmeras 4,
E-18100 Armilla, Granada, Spain
§Department of Pharmaceutical and Organic Chemistry, Faculty of Pharmacy, University of Granada,
18071 Granada, Spain
¶Department of Inorganic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela,
15782 Santiago de Compostela, Spain
¥ Present address: Department of Chemistry, University of Zurich, Winterthurerstrasse 190,
CH-8057 Zurich, Switzerland
Eight Cu(II) complexes with N-(p-, m- or o-trifluoromethylbenzyl)iminodiacetate chelators
(x-3F ligands) have been synthesized to promote C-F/H interligand interactions involving the
F3C-group: {[Cu(μ2-p-3F)(H2O)]·3H2O]}n (1), [Cu(m-3F)(H2O)2] (2), [Cu(p-3F)(Him)(H2O)]
(3), [Cu(m-3F)(Him)(H2O)] (4), [Cu(o-3F)(Him)(H2O)] (5), [Cu2(p-3F)2(H5Meim)2(H2O)2] (6),
[Cu(m-3F)(H5Meim)(H2O)] (7) and [Cu(o-3F)(H5Meim)(H2O)] (8) [Him and H5Meim =
imidazole and the “remote” tautomer 5-methylimidazole, respectively]. The compounds were
studied by single crystal X-ray diffraction, FT-IR, electronic spectra and coupled
thermogravimetric + FT-IR methods. The conformation of the iminodiacetate chelating moiety
(IDA) is fac-NO+O(apical) in 1 and mer-NO2 in 2-8. The fac-IDA conformation observed in 1 is
related to its polymeric structure and the coordination of a O’-carboxylate donor, from an
adjacent complex unit, trans to the Cu-N(IDA) bond. The mer-IDA conformation in 2 is in
agreement with similar compounds with an aqua ligand trans to the corresponding Cu-N(IDA)
bond. As expected, the ternary complexes 3-8 feature a mer-IDA conformation. Some of the
studied complexes exhibit disorder in the –CF3 group and C-H···F inter-ligand interactions along
*Corresponding author. Email: duanec@ugr.es
1

with conventional N-H···O and O-H···O interactions. The thermal decomposition of all studied
compounds under air flow produces variable amounts of trifluorotoluene.
Keywords: Copper(II) complexes; N-(Trifluoromethylbenzyl)iminodiacetate; Imidazole; Crystal
structure; C-H/F Interactions; FT-IR Spectra; Electronic spectra; Coupled TG + FT-IR analysis;
Trifluorotoluene
1. Introduction
Fluorinated compounds have gained technical [1], chemical [2] and therapeutic [3-5] relevance.
It is easy to find them in a large variety of daily life products. The fluorine is characterized by
small size, high electronegativity, low polarizability and bond strength. The replacement of
hydrogen by fluorine in organic compounds alters their physical, chemical and biological
properties [6]. Fluorine can promote different inter- and/or intra-molecular interactions, such as
C-F···H, C-F···F or C-F···π [6-9]. These interactions are normally weak, such as van der Waals
forces, nevertheless they have proved to be important in defining the molecular and/or crystal
structure of different compounds [6, 8, 9]. In contrast, fluorine directly bonded to electron-
withdrawing aromatic rings do not participate in such interactions. The role of fluoromethyl
moieties attached to aromatic rings seems to be also different, and are indeed assumed to have
the ability of taking part in C-F···H, C-F···F or C-F···π interactions [10].
Herein, the synthesis of three N-(x-trifluoromethylbenzyl)iminodiacetate(2-) ligands,
with x- being p-, m- or o-substitution in x-3F ligands, is reported. In addition, the corresponding
binary and ternary copper(II) complexes, involving one N-heterocyclic imidazole-like ligand,
were also studied. The formulas of the ligands used in this work are shown in scheme 1. This
work involves two main aims. First, to evaluate the structure of the obtained compounds. Special
attention is paid to the conformation of the chelating iminodiacetate moiety (IDA) both in binary
and ternary compounds. Second, to investigate the involvement of the trifluoromethyl group in
intermolecular interactions and their role in the crystal architecture. Therefore, single crystal
X-ray diffraction is a crucial tool [11-15]. Syntheses of the metal complexes have been carried
out in water or in methanol:water mixtures. Considering the active H-donor character of the N-H
group of imidazole ligands, we anticipate structural frameworks where a competition or
cooperation between O-H···O and/or N-H···O interactions as well as C-F···H, and related weak
2

interactions, will be operative [6-9]. In addition, the tautomerism of H(4/5)-methylimidazole
(HMeim) offers possibilities to isolate the “remote isomer” (more stable, with H5Meim) and/or
the “adjacent isomer” (more hindered, with H4Meim) in the corresponding ternary complexes
[16, 17].
2. Experimental and methods
2.1. Chemicals
Blue-greenish Cu2CO3(OH)2, imidazole, 4(5)-methylimidazole, chloroacetic acid, methanol and
KOH were supplied by Merck, Aldrich or Acros. p-, m- and o-(Trifluoromethylbenzyl)amines
were purchased from Alfa Aesar. All reagents and solvents were used as received. Caution: all
the solutions used to prepare the chelating ligands in their acid form (Section 2.2) were prepared
with CO2-free distilled water.
2.2. Synthesis of chelating ligands
In a three-necked round bottom flask, chloroacetic acid (0.12 mol, 11.34 g) was dissolved in
150 ml of water, placed in an ice-salt bath (temperature < 0 °C) under N2 stream and stirred.
KOH (0.29 mol, 16.3 g) was dissolved in 50 ml of cool water (about 0 °C) and then added
dropwise to the chloroacetic solution. To the alkaline solution of potassium chloroacetate, a 5 ml
ethanol solution of x-(trifluoromethylbenzyl)amine (x = p-, m- or o-, 0.0571 mol, 10 g) was
dropwise added. The three-necked flask with the resulting reaction mixture was then placed
inside a water bath at 85 °C, maintaining regular stirring and N2 flow during 4 h. After
condensation, the pH of the mother liquor was ~11-12. This solution was cooled in ice,
neutralized with HCl 6N, and concentrated in a Büchi evaporator (~50 °C) to a volume of 100
ml. After that, the solution was cooled again and finally acidified to pH ~2-2.5 to induce
precipitation of a white powder corresponding to the N-(x-trifluoromethylbenzyl)iminodiacetic
acids (H2p-3F, H2m-3F or H2o-3F). The H2x-3F products (C12H12F3NO4, MW 291.22) were
collected in several fractions by filtration, washed with cool water, acetone and ether, and air-
dried. Yields were ca. 50-60%. NMR and FT-IR spectra of the organic products are shown in
Supplementary Material (SM1 and SM2.1, respectively). The aforementioned procedure of
acidification must be carried out with care, gradually reducing the addition of acid after the
mother liquors have pH ~7. This is especially critical in the case of the H2o-3F acid, where the
3

solution becomes turbid near neutrality. For instance, when the mother liquor of H2o-3F acid is
cooled in an ice bath close to pH 7, precipitation of a different white product is induced. This
product was collected by filtration, washed with cool water and iPrOH and dried under air flow.
This intermediate product was identified as N-carboxymethyl-(o-trifluoromethyl)benzylamine or
o-(trifluoromethyl)tolyl-glycine (HoTTG). Yield: 2.56 g, 19.3%.
H2p-3F; relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3437, νs(H2O) 3241,
νas(CH2) 2923, νs(CH2) 2854, ν(C=O) 1733, δ(H2O) 1621, δ(CH2) 1470, δw(CH2) 1451,
ν(C-O)+δ(OH) 1399, νs(COO-) 1382, δ(OH) 1226, -CF3 1332, 1182 and 1140, π(CH)(2 adjacent
aromatic H) 826, π(OH) 739. 1H NMR (300 MHz, D2O) δ 7.84 (d, J = 8.0 Hz, 2H), 7.72 (d, J =
7.8 Hz, 2H), 4.61 (s, 2H), 3.98 (s, 4H).
H2m-3F; relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3432, νs(H2O) 3245,
νas(CH2) 2930, νs(CH2) 2855, ν(C=O) 1730, δ(H2O) 1622, δw(CH2) 1452, ν(C-O)+δ(OH) 1402,
νs(COO-) 1385, δ(OH) 1248, -CF3 1329, 1177 and 1128, π(CH)(1 aromatic H) 898,
π(CH)(3 adjacent aromatic H) 752. 1H NMR (300 MHz, D2O) δ 7.79 (m, 4H), 4.62 (s, 2H), 4.01
(s, 4H).
H2o-3F; relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3434, νs(H2O) 3251,
νas(CH2) 2936, νs(CH2) 2848, ν(C=O) 1716, δ(H2O) 1637, νas(COO-) 1609, δ(CH2) 1468,
δw(CH2) 1453, νs(COO-) 1383, δ(OH) 1238, -CF3 1311, 1171 and 1114, π(CH)(4 adjacent
aromatic H) 772, π(OH) 739. 1H NMR (300 MHz, D2O) δ 7.80 (m, 4H), 4.80 (s, 2H), 4.06 (s,
4H).
HoTTG (C10H10F3NO2, MW 233.19); relevant bands FT-IR (cm-1) and assignments:
+
νas(H2O) 3433, νs(H2O) ~3250, ν(C-H)arom2992, νas(CH2) 2927, νs(CH2) 2853, ν(NH2 ) 2580,
+
+
δ(H2O) + δ(NH2 ) 1637, νas(COO) 1605, δ(NH2 )1507, δ(CH2) 1472, δw(CH2) 1456, νs(COO)
1403 or 1385, -CF3 1315, 1182 and 1119, π(CH)(4 adjacent aromatic H) 778. 1H NMR
(300 MHz, D2O) δ 7.88 (d, J = 7.6 Hz, 1H), 7.70 (m, 3H), 4.50 (s, 2H), 3.72 (s, 2H).
2.3. Synthesis of coordination compounds
{[Cu(μ2-p-3F)(H2O)]·3H2O]}n (1). In a Kitasato flask, Cu2CO3(OH)2 (0.15 mmol, 33.2 mg) was
reacted with H2p-3F acid (0.3 mmol, 87.4 mg) in 50 ml of water, heating (~50 ºC) and stirring
for 1.5 h. The resulting clear blue solution was left to cool at room temperature and then filtered,
without vacuum, on a crystallizing dish. The solution was allowed to stand at room temperature,
4

covered with a film to control the evaporation. After one week, blue needle-like crystals were
collected. These crystals were recrystallized in 30 ml of a methanol:water mixture (2:1). After
one month, blue square crystals were obtained. Relevant bands FT-IR (cm-1) and assignments:
νas(H2O) ~3450, νs(H2O) ~3250 (shoulder), νas(CH2) 2943, νs(CH2) 2850, δ(H2O) ~1620
(shoulder), νas(COO-) 1596, δ(CH2) 1446, νs(COO-) 1384 and 1374, (F3C-) 1327, 1173 and 1127,
π(CH)(2 adjacent aromatic H of p-3F) 811. Electronic spectrum (diffuse reflectance):
ν
max 11900 cm-1.
[Cu(m-3F)(H2O)2] (2). A similar synthesis to that described for 1 was performed using
H2m-3F acid (0.3 mmol, 87.4 mg), instead of H2p-3F acid, and methanol as solvent. After one
week, a white precipitate was collected. The solution was filtered on a small crystallizing dish
and allowed to evaporate at room temperature, covered with a plastic film. Four weeks later,
parallelepiped blue crystals were obtained. Relevant bands FT-IR (cm-1) and assignments:
νas(H2O) ~3425, νs(H2O) ~3275, ν(C-H)arom 2991, νas(CH2) 2965, 2936 and 2923, νs(CH2) 2866
and ~2840 (shoulder), δ(H2O) ~1630 (shoulder), νas(COO-) 1603, δ(CH2) 1472 δw(CH2) 1454,
νs(COO-) 1396 and 1375, (F3C-) 1329, 1169 and 1140, π(CH)(1 aromatic H from m-3F) 872.
Electronic spectrum (diffuse reflectance): νmax 11900 cm-1. Electronic spectrum (diffuse
reflectance): νmax 13890 cm-1.
[Cu(p-3F)(Him)(H2O)] (3). In a Kitasato flask, Cu2CO3(OH)2 (0.15 mmol, 33.2 mg) was
reacted with H2p-3F acid (0.3 mmol, 87.4 mg) in 50 ml of distilled water under mild heating
(~50 °C) and stirring. Two hours later a clear blue solution was obtained. The solution was
cooled at room temperature and then imidazole (0.3 mmol, 20.4 mg) was slowly added to the
binary chelate solution. The reacting mixture was stirred for one hour until an intense blue
solution was obtained. Finally the solution was filtered without vacuum on a crystallizing dish
and covered with a plastic film to control the evaporation at room temperature. After four weeks,
blue square crystals were collected. Relevant bands FT-IR (cm-1) and assignments: νas(H2O)
~3400, νs(H2O) ~3250, ν(N-H) 3148, νas(CH2) 2952, νs(CH2) 2851, δ(H2O) 1626, νas(COO-)
1614, δ(N-H) 1534, δw(CH2) 1447, νs(COO-) 1396 and 1384, (F3C-) 1330, 1161 and 1134,
π(CH)(1 aromatic H from Him) 900, π(CH)(2 adjacent aromatic H from Him and p-3F) 824,
π(OH) 753. Electronic spectrum (diffuse reflectance): νmax 14800 cm-1.
[Cu(m-3F)(Him)(H2O)] (4). A similar synthesis to that described for 3 was carried out
using H2m-3F acid (0.3 mmol, 0.0874 g) instead of H2p-3F acid. Blue square crystals were
5

obtained in one week. Relevant bands FT-IR (cm-1) and assignments: νas(H2O) ~3400, νs(H2O)
~3250, ν(N-H) 3148, νas(CH2) 2941, νs(CH2) 2855, δ(H2O) 1629, νas(COO-) 1609, δ(N-H) 1501,
δ(CH2) 1501, δw(CH2) 1447, νs(COO-) 1397, (F3C-) 1331, 1166 and 1123, π(CH)(1 aromatic H
from Him and m-3F) 899 and 877, π(CH)(2 adjacent H from Him) 854, π(CH)(3 adjacent
aromatic H from m-3F) 802, π(OH) 756. Electronic spectrum (diffuse reflectance):
ν
max 14300 cm-1.
[Cu2(o-3F)2(Him)2(H2O)2] (5). A similar synthesis to that reported for 3 and 4 was
performed but using H2o-3F acid. Four days later, blue parallelepiped crystals were collected.
Relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3431, νs(H2O) ~3250, ν(N-H) 3157,
νas(CH2) 2932, νs(CH2) 2851, δ(H2O) 1635, νas(COO-) 1610, δ(N-H) 1507, δ(CH2) 1465,
δw(CH2) 1454, νs(COO-) 1384, (F3C-) 1315, 1167 and 1123, π(CH)(1 aromatic H from Him) 881,
π(CH)(2 adjacent aromatic H from Him) 824, π(CH)(4 adjacent aromatic H from o-3F) 767,
π(OH) 743. Electronic spectrum (diffuse reflectance): νmax 14350 cm-1.
[Cu2(p-3F)2(H5Meim)2(H2O)2] (6). In a Kitasato flask, Cu2CO3(OH)2 (0.15 mmol,
0.0332 g) was reacted with H2p-3F acid (0.3 mmol, 0.0874 g) in 50 ml of a MeOH:H2O mixture
(10:1), heating (~50 °C) and stirring. Two hours later, a clear blue solution was obtained. Once
the solution cooled to room temperature, H5Meim (0.3 mmol, 0.0246 g) was slowly added to the
binary chelate solution and the reaction mixture was stirred for one hour. The resulting solution,
intense blue, was filtered without vacuum on a crystallizing dish and covered with plastic film to
control the evaporation. One week later, blue square crystals were collected. Relevant bands
FT-IR (cm-1) and assignments: νas(H2O) 3419, νs(H2O) ~3250, ν(N-H) ~3150, νas(CH3) 2976,
νas(CH2) 2927, νs(CH3)~2870, νs(CH2) 2850, δ(H2O) 1624, νas(COO-) 1616, δ(N-H) 1506,
δ(CH2) 1473, δ(CH3) 1456, δw(CH2) 1447, νs(COO-) 1394 or 1384, (F3C-) 1322, 1160 and 1133,
π(CH)(1 aromatic H from H5Meim) 859, π(CH)(2 adjacent aromatic H from p-3F) 824, π(OH)
737. Electronic spectrum (diffuse reflectance): νmax 14685 cm-1.
[Cu(m-3F)(H5Meim)(H2O)] (7). A similar synthesis to that described for 5 was carried
out using H2m-3F acid (0.3 mmol, 0.0874 g) instead of H2p-3F acid. In one week, blue rhomboid
crystals were collected. Relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3410, νs(H2O)
~3250, ν(N-H) 3148, νas(CH3) 2976, νas(CH2) 2939, νs(CH3) 2876, νs(CH2) 2850, δ(H2O) 1628,
νas(COO-) 1615, δ(CH2) 1479, δ(CH3) 1454, δw(CH2) 1445, νs(COO-) 1397, (F3C-) 1334, 1165
6

and 1133, π(CH)(1 aromatic H from H5Meim and m-3F) 872, π(CH)(3 adjacent aromatic H from
m-3F) 806, π(OH) 761. Electronic spectrum (diffuse reflectance): νmax 14750 cm-1.
[Cu(o-3F)(H5Meim)(H2O)] (8). In a Kitasato flask, Cu2CO3(OH)2 (0.1 mmol, 22.1 mg)
was reacted with H2o-3F acid (0.2 mmol, 58.3 mg) in 30 ml of H2O with mild heating (~50 °C)
and stirring. Two hours later, a clear blue solution was obtained. The solution was cooled at
room temperature and then H5Meim (0.2 mmol, 16.4 mg) was slowly added to the binary chelate
solution. The reaction mixture was further stirred for one hour. The final intense blue solution
was filtered without vacuum on a crystallizing dish. The solution was left at room temperature
covered with a plastic film to control the evaporation of the solvent. One week later, blue square
crystals were obtained. Relevant bands FT-IR (cm-1) and assignments: νas(H2O) 3427, νs(H2O)
~3250, ν(N-H) 3143, νas(CH3) 2976, νas(CH2) 2933, νs(CH3) 2874, νs(CH2) 2850, δ(H2O) 1622,
νas(COO-) 1615, δ(N-H) 1507, δ(CH2) 1472, δ(CH3) 1457, δw(CH2) 1446, νs(COO-) 1384, (F3C-)
1314, 1177 and 1132, π(CH) (1 aromatic H from H5Meim) 883, π(CH) (4 adjacent aromatic H
from o-3F) 742, π(OH) 737. Electronic spectrum (diffuse reflectance): νmax 14680 cm-1.
FT-IR (SM2.2-SM2.4) and electronic spectra (diffuse reflectance, SM3) of all copper(II)
complexes are provided in Supplementary Material.
2.4. Crystal structure determinations
Suitable crystals were prepared for X-ray diffraction by immersion in perfluoropolyether, as
protecting oil for manipulation, and mounted on a MiTeGenMicromountsTM under inert
conditions. These samples were used for data collection. Data were collected with a Bruker D8
Venture diffractometer (120.0 K for 1 and 100.0 K for 2-8). Data were processed with APEX2
[18] and corrected for absorption using SADABS [19]. The structures were solved by direct
methods [20], which revealed the position of all non-hydrogen atoms. These atoms were refined
on F2 by a full-matrix least-squares procedure using anisotropic displacement parameters. All
hydrogens were located in difference Fourier maps and included as fixed contributions riding on
attached atoms with isotropic thermal displacement parameters 1.2 times those of the respective
atom. Geometric calculations were carried out with PLATON [21] and drawings were produced
with OLEX2 [22] and MERCURY [23]. A summary of crystal data as well as structure and
refinement parameters is given in table 1.
7

2.5. Other physical measurements
NMR spectra have been recorded on a 300 MHz 1H Varian Inova-TM spectrometer at room
temperature. Chemical shifts (δ) are quoted in parts per million (ppm) and are referenced to the
residual solvent peak (deuterium oxide). FT-IR spectra (KBr pellets) were recorded on a Jasco
FT-IR 6300 spectrometer. Electronic (diffuse reflectance) spectra were obtained in a Varian
Cary-5E spectrophotometer. Thermogravimetric (TG) analyses were carried out under dry air
flow (100 ml/min), from RT-800 °C, at 10 °C/min in a Shimadzu thermogravimetric analyzer
(TGA)-50H instrument, coupled to a FT-IR Nicolet Magma 550 spectrometer. A series of 20-35
FT-IR spectra were time-spaced recorded during each TG experiment. These spectra enable the
qualitative identification of the gases evolved during the experiment. The TG experiments
always start after stabilization of the balance, i.e., once reached a stable weight for each sample
is placed under dry air flow. It should be emphasized that, under these conditions, compounds
can lose a variable amount of water before each TG experiment actually starts. The fitting of the
formula and the starting material is assumed to be correct if the experimental and the calculated
data for the final residue (expected to be CuO in the studied metal complexes) are in agreement
within the experimental error, ≤ 1%.
2.6. Criteria to evaluate intermolecular interactions involving the trifluoromethyl group
The criteria reported by Reichenbächer et al. [7] were followed to explore the intermolecular
interactions involving the trifluoromethyl group. The van der Waals radii of fluorine (1.50-
1.60 Å) and hydrogen (1.20-1.45 Å) have some uncertainties, thus the averaged value was
assumed as 2.67 Å [7]. On this basis, C-F···H interactions were only considered if the
interatomic F···H distance was shorter than 2.9 Å and the angle C-F···H fell in the range
70-180°; F···F interactions were assumed to give interatomic distances shorter than 3 Å. In
C(1)-F···F-C(2) moieties, two types of interactions can be distinguished according to the C-F···F
angles (φ1 and φ2): φ1 = φ2 (Type I) or φ1~ 90° and φ2~ 180° (Type II). Due to the negative
charge density at F and the aromatic rings, C-F/π interactions should not be expected. The
geometric criteria used to search these interactions were similar to those used for C-H/π
(C-H···centroid < 3 Å, angle C-H···centroid ~180°).
8

3. Results and discussion
3.1. Molecular and/or crystal structure of binary copper(II) chelates (1 and 2)
Table 2 summarizes data concerning the copper(II) coordination of 1 and 2. Compound 1
{[Cu(μ2-p-3F)(H2O)]·3H2O]}n is a hydrated coordination polymer. This polymeric nature is
related to the chelating plus bridging role of the p-3F ligand (figure 1), involving an anti,syn-
carboxylate. The Cu(II) is best described as a distorted square-based pyramid, type 4+1. The four
closest donors to the metal are N and one O (from the monodentate carboxylate group) of the p-
3F chelator, the O-aqua and one O’ from a p-3F chelator of an adjacent complex unit within the
chain. Thus, the tridentate chelating role of the p-3F ligand implies the contribution of one
O-carboxylate as apical/distal donor and therefore the IDA moiety of the p-3F chelating ligand
can be defined as fac-NO+O(apical). Note that, in this polymeric structure, the O’-donor is
located trans to the Cu-N(p-3F) bond. No disorder was observed on the trifluoromethyl group in
p-3F. In 1, the 1D-polymeric chains extend parallel to the b axis. The aqua ligand acts twice as
H-donor for two different solvent molecules. Additional H-bonds involving non-coordinating
water and O-carboxylate acceptors build H-bonded 2D-frameworks parallel to the ab plane.
These 2D-layers have the hydrophobic p-trifluoromethylbenzyl moieties of p-3F oriented
towards their external faces and connect along the c axis by van der Waals forces, including
some C-H···F interactions (see Section 3.3).
Compound 2 agrees with the formula [Cu(m-3F)(H2O)2]. The tridentate chelating ligand
m-3F supplies the N-amino and two O-donors (from the monodentate carboxylate group) to the
base surrounding of the 4+1 copper(II) coordination polyhedron (figure 2), which is further
accomplished by the O-basal/proximal and the O-apical/distal donors of two aqua ligands.
Hence, the IDA moiety of the m-3F ligand exhibits a mer-NO2 conformation, in which the aqua
ligand is trans to the Cu-N(m-3F) bond. The crystal of 2 is built by H-bonded 2D bi-layers of
complex molecules extending parallel to the ac plane. Each aqua ligand builds two O-
H···O(carboxylate) interactions with the non-coordinated O5 and O9 carboxylate atoms from
two distinct adjacent m-3F ligands. Thus, each complex molecule is H-bonded with two
neighboring ones. In these 2D frameworks, the m-trifluoromethylbenzyl moieties of m-3M
ligands are also oriented towards their external faces. These layers are piled up along the b axis,
connected by van der Waals forces. The m-trifluoromethyl group is not involved in C-F···H (see
Section 3.3), F···F or C-F/π interligand interactions.
9

3.2. Molecular and crystal structure of mixed-ligand copper(II) complexes (3-8)
The ternary complexes 3-8 crystallized as molecular compounds, according to the general
formula [Cu(x-3F)(imidazole-like ligand)(H2O)] (figures 3 and 4). All these compounds exhibit
similar square-based pyramidal coordination, type 4+1, with lower Addison-Reedijk parameter
(τ) values than those of 1 and 2 (τ = φ-θ/60, with θ and φ being the trans-basal coordination
angles in a 4+1 surrounding, table 3). Compounds 3-8 also build crystals with rather similar
architectures. All five ternary complexes (3-8) consist of H-bonded 2D-networks of complex
molecules, layered parallel to the ab plane, where the hydrophobic x-(trifluoromethylbenzyl)
arms of the x-3F chelators orient towards their external faces. To achieve the 3D framework, the
2D layers are piled up. Further C-F···H interactions connect the 2D layers in 4-7, but these
connections are missing in 3 and 8.
In the crystals of 3, 4, 6 and 7 (having the less hindered chelators p-3F or m-3F) the
H-bonds involve two (aqua)O-H···O(carboxylate) (2.75-2.79 Å, 149-176°) and one
(imidazole)N-H···O(carboxylate) (2.72-2.76 Å, 137-150°) interactions per complex molecule. In
contrast, the two independent complex molecules in [Cu(o-3F)(Him)(H2O)] (5) build shorter
(aqua)O-H···O(carboxylate) (2.74 Å (average), 156 or 166°) and longer
(imidazole)N-H···O(carboxylate) (2.84 Å (average), 166 or 169°) interactions (figure 5). It
seems reasonable to state that the steric hindrance caused by the ortho-trifluoromethyl group in 5
and 8 is mainly tied to larger and more linear intermolecular (imidazole)N-H···O(carboxylate)
interactions, compared to the corresponding compounds having p-3F or m-3F chelators.
3.3. Interligand interactions involving the trifluoromethyl group of x-3F chelators
In the studied crystals, F···F and C-F/π interactions were not observed. In contrast, C-F···H
interligand interactions were found in five of the eight reported compounds (table 4). In these
crystals, C-F···H interactions are always accompanied by H-bonds, type N-H···O and/or
O-H···O. In 1-8, the F···H distances fall in the range 2.43-2.72 Å, and thereby rather below the
2.9 Å limit value. The C-F···H angles broadly extend in the range between 70-180° (i.e., 95-
170°). The data also reveal that these interactions are present regardless of (a) the binary (1 and
2) or ternary (3-8) nature of the copper(II) complexes and (b) the position (p-, m- or o-) of the
-CF3 group in the aromatic ring of the x-3F chelators. Only crystals of 6 and 7 feature disorder of
10

the trifluoromethyl group (with p-3F and m-3F chelators, respectively – see figures 6 and 7).
Short contact analysis of CIFs files of 6 and 7 revealed that only one of the two disordered forms
of the trifluoromethyl groups is involved in C-F···H interactions. This fact strongly suggests the
weakness of these interactions with respect to the O-H···H and N-H···O H-bonding interactions.
No structural correlation is further observed between the presence of C-F···H interligand
interactions and the disorder of the trifluoromethyl group.
3.4. Chelating ligand conformation of the IDA-group in 1-8 and related copper(II)
iminodiacetates
Another aspect to be discussed in this work concerns the conformation of the iminodiacetate
moiety within the x-3F chelating ligands. This question must be addressed differently regarding
binary and ternary complexes.
Table 5 summarizes examples of mononuclear and binuclear copper(II) chelates where
the IDA moiety exhibits a fac-NO+O(apical) conformation, with the two metal-glycinate rings
nearly perpendicular to each other and sharing the Cu-N bond. The fac-tridentate conformation
of the chelator yields two short and one long coordination bonds within the 4+1 or 4+1+1 metal
surrounding (square pyramidal or asymmetrical elongated octahedron, respectively). This
conformation is directly related to the Jahn-Teller distortions caused by the 3d9 electronic
structure of copper(II) centers. The fac-NO+O(apical) IDA conformation is usually found in
polymeric compounds where the Cu-N(IDA) and the O’-carboxylate donors (with O’- being an
O-carboxylate appertaining to the chelator of one adjacent metallic center) are trans to each
other. This is the case for 1 (figure 1). Note that in table 5 three different kinds of polymers are
found: (i) polymers having their own iminodiacetate ligand; (ii) complexes with binucleating
chelators (such as HDTA, with a 1,6-hexamethylene spacer, or p-PhDTA, with a p-phenylene
spacer); (iii) and also 1,3-thiazolidine-2,4-dicarboxylate (1,3-thiadc, a C,C’-disubstituted IDA
chelator). One compound out from this general trend is the binary Cu(II) chelate of
N-carboxymethyl-S-prolinate(2-) (cm-S-Pro, a N,C-disubstituted IDA ligand). In this case the
Cu-N(IDA) bond and one aqua ligand (instead of an O’-carboxylate donor) are trans to each
other.
Table 6 summarizes structural information on binary copper(II) compounds where the
IDA moiety of the chelator adopts a mer-NO2 conformation, that is two nearly coplanar
11

Cu-glycinate rings that share the Cu-N bond. This IDA conformation is more frequent than the
fac-NO+O(apical). The mer-NO2 conformation is found in a remarkable variety of binary
monomeric or polymeric compounds, with 4+1 and 4+1+1 copper(II) coordination. It is
noticeable that the IDA-mer-NO2 conformation is always present in molecular compounds with
Cu(II) coordination type 4+1 having two aqua ligands. Compound 2 agrees with this criterion
(figure 2). The mer-NO2 conformation is also present in polymeric compounds where the
Cu-N(IDA) bond and an aqua ligand are trans to each other, and an additional aqua or a
neighboring O’-carboxylate is on the apical/distal coordination site. Other binary Cu(II)
compounds showing the IDA-mer-NO2 conformation are polymers where the chelator have two
bridging carboxylate groups or a tridentate carboxylate group. Regarding ternary complexes, the
IDA-mer-NO2 conformation is also well-documented. For instance, this conformation has been
previously described for a variety of ternary copper(II) complexes having an iminodiacetate-like
tridentate chelator and a co-ligand which supplies one N-heterocyclic donor per metal center. No
exception has been reported to this structural correlation, including 3-8 (figures 3-8). Other
examples of ternary copper(II) complexes with typical N-heterocyclic ligands have
benzimidazole [24], H(4/5)methylimidazole [16, 17], 2,4-diaminopyrimidine [11], adenine [46]
and related N-heterocyclic bioligands [13-15, 47] such as hypoxanthine [48] or the synthetic
acyclic-nucleoside acyclovir [49].
3.5. Vibrational and electronic spectra and thermal analyses by coupled TG + FT-IR
spectroscopy
The infrared spectra of trifluoromethyl-aryl compounds exhibit at least three bands related to the
F3C- group, expected at 1321 9, 1179 7 and 1140 9 cm-1. The origin of these bands has been
controversial, probably because they are non-pure stretching bands. The last two bands can be
essentially attributed to the νas and νd modes, while the absorption near 1321 cm-1 could be a
combined band of the stretching and deformation modes of this group. The aforementioned
bands appear in spectra of the four reported organic ligands at 1322 11, 1178 7 and 1125 15,
the latter value being out of the expected range (1140 9 cm-1). The averaged values of these
bands in the corresponding spectra of the copper(II) complexes are 1325 10, 1167 12 and
1134 11 cm-1. The band near 1325 cm-1 is similar in the spectra of both the organic ligands and
the copper(II) complexes. In most of the metal complexes, the other two absorptions occur with a
12

smaller difference in wavenumber (30-45 cm-1) compared to the organic ligands. The highest
shift at lower frequencies was observed for the band near 1179 cm-1.
The electronic (diffuse reflectance) spectra of studied compounds exhibit, as expected, a
broad and asymmetric absorption with maxima ranging between 11.9 kK and 14.8 kK. Spectra of
binary chelates 1 and 2 had their maxima below 14000 cm-1 whereas the maximum absorption in
3-8 (with one Him-like ligand instead of the proximal aqua ligand in the 4+1 Cu(II)
coordination) was registered at 14300-14750 cm-1. The O-aqua substitution by N-imidazole is
performed in solutions where the H2O/imidazole molar ratio is 55.5 M/0.01 M. This is possible
due to the strong affinity of the N-imidazole donor, a borderline Pearson base, to the copper(II)
center, a borderline Pearson acid. Thus, the coordination of an imidazole instead of an O-donor
increases the ligand field and for compounds with similar coordination geometry (type 4+1 in
1-8) consequently increases the νmax values, as indeed is observed (see SM3).
All compounds reported in this work, binary (1 and 2) and ternary compounds (3-8), have
also been studied by coupled TG+IR spectroscopy. Their thermal behavior can be exemplified in
the spectra of 2 and 4. Detailed information on the TG+FT-IR measurements of both complexes
as well as additional data from 1, 3 and 5-8 can be found in the Supplementary Material SM4.
Compound 2 (see SM4.2. and table 7) decomposes in three rather different steps. The first step is
mainly characterized by the loss of both aqua ligands (the FT-IR spectra recorded at this time
also revealed the loss of some CO2). Afterwards, the decomposition of the m-3F organic ligand
occurs in a quite sharp event (weight loss ~63.5%). This process is related with the production of
CO2, H2O, CO, trifluorotoluene (TFT) and trimethylamine (TMA) as evolving gases. At higher
temperatures (> 330 °C), during the last step, N2O and NO gases instead of TMA are observed.
The weight of the final residue is in excellent agreement to that calculated for a CuO residue
(table 7).
Compound 4 (SM4.3. and table 8) exhibits an overall aqua loss process (~4.8 %) divided
in two similar steps (Ia and Ib, with a ~2.4% loss per step). Again, the corresponding FT-IR
spectra revealed the loss of some CO2 during this initial step. In this case the formation of TFT is
weakly observed (step 4) while that of TMA can be neglected. In contrast, the formation of the
three N-oxides gases (N2O, N2O and NO) are observed in the last step (370~500 °C), mainly
related to the decomposition of the 5-methylimidazole ligand. The weight of the final residue
13

(about 600 °C) agrees to that calculated for a non-pure CuO residue within an experimental error
< 1%.
The formation of different amounts of TMA and TFT is also observed in all the p-3F,
m-3F and o-3F derivatives here reported. This fact strongly suggests that the decarboxylation of
the x-3F chelators can be followed by the appropriate recombination process. This singularity
should be only understood as one decomposition possibility, among others, also associated to the
well-known thermodynamic stability of the C-F bonds. In this regard similar TG-experiments
also revealed the formation of TMA during the thermal decomposition of Cu(II) complexes with
N-methyl-IDA [46] or N-benzyl-IDA (unpublished results).
4. Concluding remarks
Binary 1 showed a polymeric nature and the iminodiacetate chelating moiety in fac-NO+O
conformation. In contrast, 2-8 have a molecular nature and exhibit a mer-NO2 conformation. All
copper(II) complexes have in common the coordination of aqua ligands (1-8). The formation of
rather strong N-H···O and/or O-H···O interactions do not preclude the formation of C-H···F
interactions (1, 4-7). However, C-F/π or F···F interactions are missing. Appropriate comparisons
revealed that the C-H···F interactions occur irrespective of (a) the dimensionality of the
compounds (polymeric (1) or molecular (2-8) structures) and (b) the binary (1 and 2) or mixed-
ligand nature (3-8) of the compounds. No further structural correlation was observed between the
presence of C-F···H interligand interactions and the disorder on the trifluoromethyl group.
Supplementary material
1H NMR spectra of the chelating H2x-3F ligands and the HoTTG by-product are given in SM1.
FT-IR spectra of the organic acids (SM2.1) and metal complexes 1-8 (SM2.2-SM2.3), electronic
spectra of 1-8 (SM3), coupled TG+FT-IR results on 2 and 4 are provided. Crystallographic data
for the structural analysis have been deposited in the Cambridge Crystallographic Data Centre,
CCDC 1040268-1040275 (1-8). These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html or from the Cambridge Crystallographic Data
Center, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: +44 (0) 1223336033; E-mail:
deposit@ccdc.cam.ac.uk).
14

Acknowledgements
Financial support from the Research Group FQM-283 (Junta de Andalucía) and MICINN-Spain
(Project MAT2010-15594) is acknowledged. The project “Factoría de Cristalización,
CONSOLIDER INGENIO-2010” provided X-ray structural facilities. ERDF Funds and Junta de
Andalucía support to acquire the FT-IR spectrophotometer Jasco 6300 is acknowledged. ADM
acknowledges a postdoctoral fellowship from Fundacion Ramon Areces.
References
[1]
[2]
P. Alonso, P. Pardo, F.J. Fananas, F. Rodríguez. Chem. Commun., 50, 14364 (2014).
T.J. Cogswell, C.S. Donald, D.-L. Long, R. Márquez. Org. Biomol. Chem., (2014)
http://dx.doi.org/10.1039/C4OB01547A
[3]
[4]
[5]
[6]
[7]
[8]
[9]
S. Purser, P.M. Moore, S. Swallow, V. Gouverneur. Chem. Soc. Rev., 37, 320 (2008).
R. Filler, R. Saha. Future Med. Chem., 777 (2009).
B.E. Smart. J. Fluorine Chem., 109, 3 (2001).
A.R. Choudhury, T.N. Guru Row. Cryst. Growth Des., 4, 47 (2004).
K. Reichenbächer, H.I. Süss, J. Hulliger. Chem. Soc. Rev., 34, 22 (2005).
D. Chopra, V. Thiruvenkatam, T.N. Guru Row. Cryst. Growth Des., 6, 843 (2006).
P. Panini, D. Chopra. CrystEngComm., 15, 3711 (2013).
[10] C.K. Mariamma, H.T. Varghese, C.Y. Panicker, K. John, J. Vinsova. Spectrochim. Acta,
Part A, 112, 161 (2013).
[11] H. El Bakkali, D. Choquesillo-Lazarte, A. Domínguez-Martín, M.I. Pérez-Toro, L.
Lezama, J.M. González-Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. Cryst. Growth Des.,
14, 889 (2014).
[12] H. El Bakkali, A. Castiñeiras, I. García-Santos, J.M. González-Pérez, J. Niclós-Gutiérrez.
Cryst. Growth Des., 14, 249 (2014).
[13] A. Domínguez-Martín, A. García-Raso, C. Cabot, D. Choquesillo-Lazarte, I. Pérez-Toro,
A. Matilla-Hernández, Alfonso Castiñeiras, J. Niclós-Gutiérrez. J. Inorg. Biochem., 127,
141 (2013).
[14] A. Domínguez-Martín, D. Choquesillo-Lazarte, J.A. Dobado, I. Vidal, J.M. González-
Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. Dalton Trans., 42, 6119 (2013).
15

[15] A. Domínguez-Martín, D. Choquesillo-Lazarte, J. Dobado, H. Martínez-García, L.
Lezama, J.M. González-Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. Inorg. Chem., 52,
1916 (2013).
[16] H. El Bakkali, A. Domínguez-Martín, D. Choquesillo-Lazarte, E. Vílchez-Rodríguez,
J.M. González-Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. Inorg. Chem. Commun., 42, 20
(2014).
[17] O.Z. Yesilel, G. Günay, S.W. Ng. J. Coord. Chem., 67, 2564 (2014).
[18] BRUKER, APEX2 Software (V2014.7). Bruker AXS Inc., Madison, Wisconsin, USA
(2014).
[19] G.M. Sheldrick, SADABS, Program for Empirical Absorption Correction of Area
Detector Data, University of Göttingen, Germany (2009).
[20] G.M. Sheldrick. ActaCrystallogr., A64, 112 (2008).
[21] A.L. Spek, PLATON, A Multipurpose Crystallographic Tool, Utrecht University,
Utrecht, The Netherlands (2014).
[22] O.V. Dolomanov, L.J. Bourhis, R.J. Gildea, J.A.K. Howard, H. Puschmann. J. Appl.
Cryst., 42, 339 (2009).
[23] C.F. Macrae, I.J. Bruno, J.A. Chisholm, P.R. Edgington, P. McCabe, E. Pidcock, L.
Rodríguez-Monge, R. Taylor, J. van de Streek, P.A. Wood. J. Appl. Cryst., 41, 466
(2008).
[24] M.J. Román-Alpiste, J.D. Martín-Ramos, A. Castiñeiras-Campos, E.Bugella-Altamirano,
A.G. Sicilia-Zafra, J.M. González-Pérez, J. Niclós-Gutiérrez. Polyhedron, 18, 3341
(1999).
[25] F.G. Kramarenko, T.N. Polynova, M.A. Porai-Koshits, V.P. Chalyi, G.N. Kupriyanova,
L.I. Martynenko. Zh. Strukt. Khim., 14, 744 (1973).
[26] A. Podder, J.K. Dattagupta, N.N. Saha, W.Saenger. Acta Crystallogr., B35, 53 (1979).
[27] Q. Zhong, Y.-H. Wang, X.-T. Zhang. Acta Crystallogr., E67, m1528 (2011).
[28] G.V. Khvorykh, L.I. Martynenko. Koord. Khim., 20, 624 (1994).
[29] L. Zheng, Z.-H. Ni, W.-L. Li, L.-F. Zhang, C.-H. Ge, A.-L. Cui, H.-Z. Kou.
JiegouHuaxue, 27, 793 (2008).
[30] Y.-Y. Yin, Y.-L. Zhao, J.-G. Ma, X.-C. Cao, P. Cheng. Inorg. Chem., 52, 3738 (2013).
[31] Y.-Y. Yin, X.-C. Cao, P. Cheng, J.-G. Ma. Inorg. Chem. Commun., 24, 7 (2012).
16

[32] I.F. Burshtein, A.L. Poznyak, L.V. Stopolyanskaya. Kristallografiya, 45, 259 (2000).
[33] Y.-T. Chen, H.-Q. Liu, J.-J. Liu, X.-H. Bu, J.-L. Wang, L.-J. Zhang, F.-M. Miao. J.
Coord. Chem., 25, 43 (1992).
[34] P.X. Rojas-González, D. Choquesillo-Lazarte, J.M. González-Pérez, S.A. Ruiz-García, R.
Carballo, A. Castineiras, J. Niclós-Gutiérrez. Polyhedron, 22, 1027 (2003).
[35] J.-L. Wang, G.-H. Tian, F.-M. Miao, H.-Q. Liu, R.-T. Chen. JiegouHuaxue, 11, 384
(1992).
[36] R. Fernández-Pinar, C. Sánchez de Medina-Revilla, A. Domínguez-Martín, M.P. Brandi-
Blanco, D. Choquesillo-Lazarte, J.M. González-Pérez, J. Niclós-Gutiérrez. Z. Anorg.
Allg. Chem., 633, 2658 (2007).
[37] M.A. Hidalgo, J. Romero, J. Suárez-Varela, J.C. Avila-Rosón, J.D. Martín-Ramos. Acta
Crystallogr., C51, 1512 (1995).
[38] X.-J. Chen, Y. Yang, W.-W. He, J.-F. Ma. Polyhedron, 65, 141 (2013).
[39] C. Ruiz-Pérez, M.L. Rodríguez, F.V. Rodríguez-Romero, A. Mederos, P. Gili, P. Martín-
Zarza. Acta Crystallogr., C46, 1405 (1990).
[40] T.N. Polynova, N.V. Dvortsova, T.V. Filippova, M.A. Porai-Koshits, Yu.V. Nekrasov.
Koord. Khim., 12, 1484 (1986).
[41] J.E.W. Cull, F. Habib, I. Korobkov, M. Murugesu, J. Scott. Inorg. Chim. Acta, 370, 98
(2011).
[42] J. Fielden, K. Quasdorf, A. Ellern, P. Kogerler. Eur. J. Inorg. Chem., 717 (2009).
[43] X. Xu, X. Pan, S. Tang, X. Lv, L. Li, X. Zhao. Z. Anorg. Allg. Chem., 639, 967 (2013).
[44] J.M. Tercero, A. Matilla, J. Niclós, A. Castineiras. J. Coord. Chem., 34, 139 (1995).
[45] N.-H. Dung, B. Viossat, A. Busnot, E. Abarca-García, J. Niclós-Gutiérrez, M.F. Gardette.
Inorg. Chim. Acta, 175, 155 (1990).
[46] E. Bugella-Altamirano, D. Choquesillo-Lazarte, J.M. González-Pérez, M.J. Sánchez-
Moreno, R. Marín-Sánchez, J.D. Martín-Ramos, B. Covelo, R. Carballo, A. Castiñeiras,
J. Niclós-Gutiérrez. Inorg. Chim. Acta, 339, 160 (2002).
[47] A. Domínguez-Martín, D. Choquesillo-Lazarte, J.M. González-Pérez, A. Castiñeiras, J.
Niclós-Gutiérrez. J. Inorg. Biochem., 105, 1073 (2011).
[48] D.K. Patel, D. Choquesillo-Lazarte, A. Domínguez-Martín, M.P. Brandi-Blanco, J.M.
González-Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. Inorg. Chem., 50, 10549 (2011).
17

[49] M.P. Brandi-Blanco, D. Choquesillo-Lazarte, A. Domínguez-Martín, J.M. González-
Pérez, A. Castiñeiras, J. Niclós-Gutiérrez. J. Inorg. Biochem., 105, 616 (2011).
18

Figure 1. Fragment of 1 showing the 4+1 Cu(II) coordination. The O9 donor is at the apical site.
The p-3F chelator adopts a fac-NO+O conformation. The anti,syn-bridging carboxylate is shown.
Figure 2. Asymmetric unit of 2 showing the mer-NO2 conformation of the IDA moiety of the m-
3F chelator.
Figure 3. Asymmetric unit of 3 showing the IDA-mer-NO2 conformation of the p-3F chelator
and the apical aqua ligand.
Figure 4. Asymmetric unit of 4 showing the IDA-mer-NO2 conformation of the m-3F chelator
and the apical aqua ligand.
Figure 5. Two non-equivalent complex molecules in the asymmetric unit of the crystal of 5. The
IDA-mer-NO2 conformation of the o-3F chelator is shown as well as the (Him)N-
H···O(coordinated, o-3F) interaction connecting these molecules.
Figure 6. Asymmetric unit of 6 showing the disorder of the trifluoromethyl group and the mer-
NO2 conformation of the IDA moiety in p-3F.
Figure 7. Asymmetric unit of 7 showing the disorder of the trifluoromethyl group and the mer-
NO2 conformation of the IDA moiety in m-3F.
Figure 8. Asymmetric unit of 8 showing the IDA-mer-NO2 conformation of the chelator o-3F.
19

Table 1. Summary of crystal data, structure solution and refinement of 1-8.
Comp
ound
1
2
3
4
5
6
7
8
Empiri C12H18Cu C12H14Cu C15H16Cu
C15H16Cu
F3N3O5
C30H32Cu2F C32H36Cu2F C16H18Cu
C16H18Cu
F3N3O5
cal
F3NO8
F3NO6
388.78
F3N3O5
438.85
6N6O10
6N6O10
F3N3O5
formul
a
Formul 424.81
438.85
877.69
905.75
452.87
452.87
a
weight
T (K)
120.2
100.0
100.0
100.0
100.0
299.7
99.9
100.0
Wavele 0.71073
0.71073
1.54178
1.54178
0.71073
0.71073
0.71073
0.71073
ngth
(Å)
Crystal Monoclin Monoclin Orthorho
Orthorho
mbic
Monoclinic Monoclinic Orthorho
mbic
Orthorho
mbic
system ic
ic
mbic
Space
group
P21/c
P121/n1
Pbca
Pbca
P21
P21/c
Pbca
Pbca
Unit
cell
dimens
ions
a (Å)
b (Å)
9.235(1)
9.965(1)
7.384(4)
11.972(2)
11.821(4)
10.790 (9)
11.201(9)
11.943 (2)
12.451 (2)
11.953(9)
11.880(4)
26.841(19 12.210(3) 12.861(5)
)
12. 483(8) 12.442(3)
c (Å)
α (º)
β (º)
18.744(3) 7.533(3)
90 90
25.398(3) 22.500(8)
13.876(11) 25.855(4)
24.838(2) 24.838(2)
90
90
90
90
90
90
90
90
90
90.688(7) 92.149(10 90
)
92.682(3)
90.011(4)
γ (º)
Z
90
4
90
90
90
90
90
90
90
4
8
8
2
4
8
8
F(000) 868
788
2582
1784
3260
1784
3499
892
4189
1848
7833
1848
3787
1848
5176
Indep.
reflecti
ons
2986
GOF
on F2
1.083
0.049
1.047
0.050
1.069
0.042
1.019
0.034
1.060
0.037
1.066
0.042
1.044
0.033
1.060
0.046
Final
R1 [I >
2σ]
Final
wR2
0.126
0.095
0.111
0.074
0.082
0.105
0.079
0.112
Largest 1.083/-
diff. 0.981
0.767/-
0.608
0.618/-
0.510
0.533/-
0.403
1.197/-
0.771
0.399/-
0.488
0.449/-
0.360
0.776/-
0.819
20

peak
/hole
21

Table 2. Selected copper(II) coordination data in the binary compounds (bond lengths (Å), trans-basal
angles (º)).
Compound
1
2
Chelator
m-3F
μ2-p-3F
IDA-group conformation
Cu-N(x-3F chelator)
fac-NO+O(apic)
2.048(3)
1.950(2)
2.239(2)!
1.947(2)
1.985(2)
-
mer-NO2
2.012(4)
1.926(3)
1.938(3)
-
Cu-O(x-3F chelator)
Cu-O(x-3F chelator)
Cu-O#1(x-3F adjacent chelator)
Cu-OW1(aqua, basal)
Cu-O2(aqua, apical)
1.942(3)
2.281(4)
157.45(14)
171.28(12)
0.23
trans- N-Cu-O` *
171.83(11)
158.45(11)
0.22
trans-O(carboxylate)-Cu-O(aqua, basal)
Addison-Reedijk parameter (τ)
* O’ is a carboxylate atom from
the p-3F chelator of the adjacent
complex unit in the polymeric
chain.
22

Table 3. Selected copper(II) coordination data in the ternary compounds (bond lengths (Å), trans-basal
angles (º)).
Compound
3
4
5
6
7
8
Chelator
p-3F
mer-
m-3F
o-3F
p-3F
m-3F
o-3F
IDA group
conformation NO2
mer-
NO2
mer-NO2
mer-NO2
mer-
NO2
mer-NO2
N-coligand
Him
Him
Him
H5Meim
1.944(3)
H5Mei
m
H5Meim
Cu-
1.954(2) 1.945(2) 1.948(5)
1.952(5)
1.944(3)
1.949(2) 1.953(3)
N(imidazole-
like ligand)
Cu-N(x-3F
chelator)
2.000(2) 2.003(2) 2.017(5)
1.959(2) 1.962(2) 1.956(4)
1.976(2) 1.972(2) 1.992(4)
2.344(2) 2.313(2) 2.231(5)
168.71( 169.04( 169.5(2)
2.009(5)
1.954(4)
1.982(4)
2.214(4)
165.5(2)
1.993(2)
1.955(2)
1.977(2)
2.328(2)
1.993(2)
1.954(2)
1.974(2)
2.327(2)
2.002(2) 2.005(2)
1.964(2) 1.973(2)
1.975(2) 1.982(2)
2.293(2) 2.321(2)
Cu-O(x-3F
chelator)
Cu-O(x-3F
chelator)
Cu-O2(aqua,
apical)
trans- N-Cu-
N(imidazole- 9)
like ligand)
169.56(1 169.51(1 169.87( 168.64(1
2) 2) 7) 1)
8)
trans-
168.37( 167.74( 166.56(1 166.81(1 168.18(9) 168.04(9) 167.74( 168.45(9)
O(carboxylate 8)
)-Cu-O(aqua,
basal)
7)
6)
7)
6)
Addison-
Reedijk
0.01
0.02
0.05
0.02
0.02
0.03
0.04
0.003
parameter (τ)
23

Table 4. Interligand C-F···H interactions, including F···H bond lengths (<2.9 Å) and C-F···H
angles (º).
N-
-CF3
Compound Chelator
Distance F···H Angle C-F···H
coligand disorder
-
no
F18···H6B
2.603
C17-F18···H6B
117.83
1
μ2-p-3F
F19···H2B
2.543
C17-F19···H2B
166.04
F20···H2A
2.661
C17-F20···H2A
123.34
m-3F
p-3F
m-3F
-
no
no
no
-
-
-
-
2
3
4
Him
Him
F18···H13
2.488
C17-F18···H13
112.84
F20···H24
2.461
C17-F20···H24
176.12
o-3F
Him
no
F15···H48
2.719
C13-F15···H48
142.07
5
F15···H49
2.712
C13-F15···H49
166.33
F16···H40B
2.363
C13-F16···H40B
106.52
F45···H10A
2.532
C43-F45···H10A
96.21
F45···H49
2.616
C43-F45···H49
136.26
F46···H10A
2.431
C43-F46···H10A
102.10
p-3F
m-3F
o-3F
H5Meim yes
H5Meim yes
H5Meim no
F18A···H56C
2.547
F46A···H26C
2.632
C15-
F18A···H56C
119.23
6
7
8
C45-
F46A···H26C
118.30
F1A···H10A
2.561
C12-F1A···H10A
113.54
F2A···H8
2.565
F2A···H26C
2.661
C12-F2A···H8
158.94
C12-F2A···H26C
117.58
-
-
24

Table 5. Copper(II) iminodiacetate-like chelates with the IDA moiety in fac-NO+O (apical)
conformation.
trans-
Compound
or CSD ref.
code
donor
to the
Cu-N
bond
Cu(II)
coord.
Apical
donor(s)
Chelator* R* group FORMULA
Reference
Compound 1 p-3F
p-(tfm)Bz {[Cu(p-3F)(H2O)]·3H2O}n 4+1
O’
O(carboxyl) This
work
CUBMER
CUIMAC
CUIMAC01
YADVUW
YEWJIT
IDA
H
{[Cu(µ2-IDA)(H2O)2]}n
4+1+1 O’
OW2 and
[24]
O(carboxyl) [25]
[26]
IDA
H
{[Cu(µ2-IDA)(H2O)]}n
4+1
4+1
O’
O’
O(carboxyl) [27]
O(carboxyl) [28]
HDTA
C6-alkyl
{[Cu2(µ4-
HDTA)(H2O)2]·4H2O}n
BODYID
SENTOW
REDWEE
WITRUM
p-PhDTA p-
{[Cu2(µ4-
4+1
O’
O(carboxyl) [29]
phenylene PhDTA)(dmso)2]·4dmso}n
1,3-
thiadc
1,3-thia
1,3-thia
{[Cu(µ2-1,3-
thiadc)(H2O)2]·H2O}n
4+1+1 O’
O(carboxyl) [30]
and OW2
1,3-
{[Cu(µ2-1,3-
thiadc)(DMF)]}n
4+1
4+1
O’
O(carboxyl) [31]
thiadc
cm-S-Pro
{[Cu(µ2-cm-S-
OW!
O(carboxyl) [32]
Pro)(H2O)]·2H2O}n
*Abbreviations for some chelators and groups: p-(tfm)Bz, p-(trifluoromethyl)benzyl; HDTA, 1,6-
hexamethylenedianinotetraacetate(4-) ligand; C6-alkyl, n-hexamethylene spacer; p-PhDTA, p-
phenylenediamine-N,N,N',N'-tetra-acetato(4-) ligand; p-phenylene, 1,4-phenylene spacer, 1,3-thiadc,
1,3-thiazolidine-2,4-dicarboxylato(2-) ligand ; 1,3-thia, 1,3-thiazolidine; cm-S-Pro, N-(carboxymethyl)-
S-prolinato(2-) ligand.
25

Table 6. Copper(II) iminodiacetate-like chelates with the IDA moiety in mer-NO2
conformation.
trans
-
Cu(II
Compound
or CSD ref. Chelator* R* group
code
dono Apical
)
Referenc
e
FORMULA
r to
Cu-
N
donor(s
)
coord
.
bond
m-3F
m-tfmBz
[Cu(m3F)(H2O)
4+1
4+1
OW1 OW2
This
work
2
SUCXET
VAMJUP
VUSHOG
o-tolIDA o-tolyl
TEBIDA tert-Bu
p-tolIDA p-tolyl
[Cu(o-tIDA)(H2O)2]
OW1 OW2
OW1 OW2
OW1 OW2
[33]
[34]
[35]
[Cu(TEBIDA)(H2O)2] 4+1
[Cu(p-
4+1
tolylIDA)(H2O)2]
YIPWEA
BCAA
1-adamantyl
[Cu(BCAAA)(H2O)2]
4+1
OW1 OW2
OW1 OW2
[36]
[37]
ZAMBUK 2EtPhID N2-Et-phenyl [Cu(2EtPhIDA)(H2O)2 4+1
A
]
LIRMIK
L
Diarylalkyl
[Cu2(mu2-
Q)(H2O)4]·4H2O
4+1
OW1 OW2
[38]
[39]
VENBEV
p-PhDTA p-phenylene
{[Cu2(µ4-p-
4+1+ OW1 OW2
PhDTA)(H2O)4]·2H2O
1
and O’
}
n
CUEDTA0 EDTA
1
1,2-ethylene
{]Cu2(µ4-
EDTA)(H2O)2]·2H2O}
4+1
OW
O’
O’
[40]
n
ONAMAS MIDA
Me
{[Cu(µ3-MIDA)]}n
4+1
O”
[41]
[42]
SOSWAZ
DINFOX
ZUFSEY
1pheida
2MeBz
{[Cu(µ3-1pheida)]}n
4+1+ O’
1
O’ y
O”
p-tm-
XDTA
tm-xyl
{[Cu2(µ6-p-tm-
XDTA)]}n
4+1
O’
O”
[43]
[44]
CMThreo C-
{[Cu(µ2-
4+1+ O’
1
OW
and O”
(hydroxyethyl CMT)(H2O)]}n
)
SISCUS
SENTIQ
cm-L-Phe C-benzyl
{[Cu(cm-L-
Phe)(H2O)]}n
4+1+ O’
1
OW
and O”
[45]
1,3-
1,3-thia
{[Cu(1,3-
thiadc)(H2O)]}n
4+1+ O’
1
O’ and [32]
O”
thiadc
*Abbreviations for some N-substituent of IDA-groups (unless indicated a C-
substitution): m-(tfm)Bz, m-(trifluoromethyl)benzyl; Diarylalkyl, 4.4’dimethylene-
26

1,1’-diphenyl spacer; 2MeBz, o-tolyl-methyl; tm-xyl, 2,4,5,6-tetramethyl-p-xylyl
spacer; 1,3-thia, 1,3-thiazolidine.
27

28