Solvent-controlled formation of monomeric and dimeric species containing Cu(II) acetate and 4-phenylpyridine

Article abstract of DOI:10.1016/j.poly.2017.06.049

Three copper(II) acetate complexes with 4-phenylpyridine (4-Phpy), namely [Cu(MeCO₂)₂(4-Phpy)₂(H₂O)₂] (1), [Cu(MeCO₂)₂(4-Phpy)₂(H₂O)_1.5] (2) and [Cu(MeCO₂)₂(4-Phpy)]₂ (3), were synthesized and characterized by analytical and spectroscopic methods. Experimental conditions as solvent or temperature determine the species obtained. Crystal and molecular structure of 2 was determined by X-ray diffraction. Compound 2 presents a singular structure, containing two crystallographic independent mononuclear units [Cu(MeCO₂)₂(4-Phpy)₂(H₂O)₂] (2A) and [Cu(MeCO₂)₂(4-Phpy)₂(H₂O)] (2B) in its unit cell and each of these forms an independent 1-D chain through H-bonding.

Full text of DOI:10.1016/j.poly.2017.06.049

Accepted Manuscript
Solvent-controlled formation of monomeric and dimeric species containing
Cu(II) acetate and 4-phenylpyridine
Joan Soldevila-Sanmartín, José A. Ayllón, Teresa Calvet, Mercè Font-Bardia,
Josefina Pons
PII:
S0277-5387(17)30467-9
DOI:
http://dx.doi.org/10.1016/j.poly.2017.06.049
POLY 12730
Reference:
Polyhedron
To appear in:
Received Date:
Accepted Date:
12 May 2017
28 June 2017
Please cite this article as: J. Soldevila-Sanmartín, J.A. Ayllón, T. Calvet, M. Font-Bardia, J. Pons, Solvent-controlled
formation of monomeric and dimeric species containing Cu(II) acetate and 4-phenylpyridine, Polyhedron (2017),
doi: http://dx.doi.org/10.1016/j.poly.2017.06.049
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Submitted to Polyhedron
Prof. Josefina Pons
Departament de Química
Universitat Autònoma de Barcelona
08193-Bellaterra-Cerdanyola,
Barcelona, Spain
Fax: 34-93 581 31 01
e-mail: Josefina.Pons@uab.cat
Solvent-controlled formation of monomeric and dimeric species
containing Cu(II) acetate and 4-phenylpyridine
Joan Soldevila-Sanmartín, a José A. Ayllón,a* Teresa Calvet,b Mercè Font-Bardia,c and Josefina
Pons,a*
aDepartament de Química, Universitat Autònoma de Barcelona, 08193-Bellaterra, Barcelona,
Spain
bCristal·lografia, Mineralogia i Dipòsits Minerals, Universitat de Barcelona, Martí i Franquès
s/n, 08028-Barcelona, Spain.
cUnitat de Difracció de Raig-X, Centres Científics i Tecnològics de la Universitat de Barcelona
(CCiTUB), Universitat de Barcelona, Solé i Sabarís, 1-3, 08028-Barcelona, Spain.
Keywords: Cu(II) acetates; Cu(II) monomer; Cu(II) paddle-wheel; Bulky pyridine ligand;
Supramolecular networks.
1

Abstract
Three copper(II) acetate complexes with 4-phenylpyridine (4-Phpy), namely
[Cu(MeCO2)2(4-Phpy)2(H2O)2] (1), [Cu(MeCO2)2(4-Phpy)2(H2O)1.5] (2) and
[Cu(MeCO2)2(4-Phpy)]2 (3), were synthesized and characterized by analytical and
spectroscopic methods. Experimental conditions as solvent or temperature determine
the species obtained. Crystal and molecular structure of 2 was determined by X-ray
diffraction. Compound 2 presents a singular structure, containing two crystallographic
independent mononuclear units [Cu(MeCO2)2(4-Phpy)2(H2O)2] (2A) and
[Cu(MeCO2)2(4-Phpy)2(H2O)] (2B) in its unit cell and each of these forms an
independent 1-D chain through H-bonding.
2

1. Introduction
The formation of secondary building units (SBUs) with interesting supramolecular
features in a controlled fashion, such as 1D chains, 2D sheets or 3D porous frameworks
is a current milestone in inorganic chemistry [1-3]. In this topic, the combination of
metal centers with carboxylates and pyridines has attracted attention due the fact that
pyridines provide structural rigidity and could force the direction of the hydrogen bond
propagation [4]. Cu(II) is a typical choice for metal center due its variety of
coordination modes and molecular topologies. An important family of Cu(II) based
SBUs are dimeric paddle-wheel like complexes [5,6]. Interestingly, when paddle-wheel
like dimers crystallizes, usually mononuclear species with octahedral, square pyramidal
or square planar geometries are also formed. This dimer-monomer equilibrium in Cu(II)
carboxylate derivatives with pyridines or other auxiliary ligands has been known since
decades and thoroughly studied [7-10]. Despite their efforts, most studies do not
provide a clear explanation of the mechanism that governs the formation of either the
dimeric or the monomeric compound. Furthermore, reports in the literature where the
monomeric and dimeric structures for the same choice ligands are isolated and
characterized are scarce [11-13].
Recently in our group, we have assayed the reaction between M(MeCO2)2·H2O (M =
Cu(II), Zn(II) and Cd(II); MeCO2 = Acetate), 1,3-benzodioxole-5-carboxylic acid
(HPip) and different bulky pyridine derivatives. Thus, dimeric and monomeric
compounds were obtained [14-16]. Specifically, we have assayed the reaction of
Cu(MeCO2)2·H2O, with HPip and 3-phenylpyrydine (3-Phpy) or 4-benzylpyrydine (4-
Bzpy), obtaining paddle-wheel dimers and mononuclear compounds in the same
reaction. However using 4-phenylpyrydine (4-Phpy) only a dimeric compound [Cu(µ-
Pip)(Pip)(4-Phpy)]2 is obtained [16].
3

As a continuation of these works, in this paper we study the reaction between
[Cu(MeCO2)2(H2O)]2 and 4-Phpy, a system that yields two new monomeric hydrated
complexes besides the known paddle-wheel dimeric compound [17]. All reactions were
assayed at room temperature, and the obtaining of one or another compound depends on
the solvent employed in the preparations. All compounds were fully characterized and
the X-ray crystal structure of 2 is presented.
2. Results and discussion
2.1. Synthesis and general characterization
The reaction between Cu(MeCO2)2·H2O and 4-Phpy in a methanol:water (MeOH:H2O,
1:1) mixture as solvent at room temperature, using 1:1 Cu:4-Phpy molar ratio, yielded
compound [Cu(MeCO2)2(4-Phpy)2(H2O)2] (1). However, the same reaction assayed in
an ethanol:water (EtOH:H2O, 1:1) mixture as solvent results in the formation of
compound [Cu(MeCO2)2(4-Phpy)2(H2O)1.5] (2). The same reactions in absence of H2O,
using EtOH or MeOH as solvent, result in the formation of paddle-wheel dimer
[Cu(MeCO2)2(4-Phpy)]2 (3). Compound 2 can also be obtained via recrystallization of 3
in MeOH:H2O (1:1) mixture (Scheme 1). Therefore, the formation of a monomeric, 1
and 2, or a dimeric, 3, compound is controlled by the presence of a sizeable quantity
H2O in the reaction media (50 %). Our results agree with the fact that the role of water
as one of the key factors governing the formation of either monomeric or dimeric
compounds has been already identified in the literature [7-11,13,18]. Furthermore, the
use of different alcohols as co-solvents also results in the isolation of two differentiate
compounds, 1 in MeOH and 2 in EtOH.
4

Dimer 3 has already been described in the literature [17] but herein we report a different
synthetic procedure. In the reported procedure, the dimer was obtained working in a 1:1
metal to 4-Phpy ratio, using a MeCN:MeOH:H2O mixture (1:1:1, MeCN = acetonitrile)
as solvent and heating at 60°C for 15 minutes. Despite the presence of H2O as co-
solvent in the reported synthesis, the dimeric compound (3) is obtained. This fact is
probably due the heating at 60°C, as it will be demonstrated later in this work.
The elemental analyses of 1-3 are consistent with the proposed formulas. Phase purity
of 1-3 was confirmed via Powder X-ray diffraction (PXRD) (Fig. S1-S3). ATR-FTIR
spectrum of 1 and 2 show significant shifts in the ν(C=O) and ν(C-O) stretching with
respect to the spectra of [Cu(MeCO2)2(H2O)]2 (Fig. S4-S5), hence confirming the
different coordination mode of the Cu(II) to the carboxylate groups of MeCO2 ligands.
However, for compound 3 no significant variations could be found in ν(C=O) and ν(C-
O) stretching (Fig. S6). For 1-3, the presence of ν(C=C)ar and ν(C=N)ar bands confirm
the coordination of 4-Phpy. Additionally, the coordination mode of the carboxylate
groups can be inferred from the difference between the asymmetric and symmetric
vibrations of the COO- groups (Δ = νCOOasym–νCOOsym) [19]. The values of Δ = 215
cm-1 for 1 and Δ = 213 cm-1 for 2 show a monodentate mode whereas for compound 3 Δ
= 189 cm-1 shows bidentate bridging mode [19]. For compound 2, the value (Δ) is
coherent with its elucidated X-ray crystal structure.
As described in section 4.5, heating blue monomeric compounds 1 or 2 at 50ᵒC during
32 h resulted in the formation of the green dimer 3. This conversion processes were
confirmed via PXRD (Fig. 1). This monomeric to dimeric conversion has also been
reported previously in the literature [7-10,13]. It is also noteworthy that this
transformation also happens at room temperature when monomeric species are treated
with EtOH.
5

2.2 Crystal and extended structure of complex 2
Suitable crystals for X-ray diffraction where obtained via recrystallization of compound
3 in an EtOH:H2O mixture in a 1:1 proportion. The X-ray crystallographic analyses
reveal that the crystal structure of compound 2 contains two crystallographic
independent monomers [Cu(MeCO2)2(4-Phpy)2(H2O)2] (2A) and [Cu(MeCO2)2(4-
Phpy)2(H2O)] (2B) in its unit cell (Fig. 2). In each monomer, the copper cation is linked
to two monodentate MeCO2 and two 4-Phpy ligands. The main difference between the
two monomers is due the number of coordinated H2O molecules that in turn depends on
the different conformations assumed by the acetate anions. Monomer 2A presents an
asymmetric unit consisting of a Cu(II) atom in a special position (inversion center), one
monodentate MeCO2 anion, one 4-Phpy, and one H2O molecule. Each of the
independent Cu(II) center is six-coordinated, having a distorted octahedral geometry.
Monomer 2B, on the other hand, contains only one H2O molecule, resulting in a slightly
distorted square pyramidal geometry (τ = 0.093) [20]. In the asymmetric unit the Cu1B
atom is located on a twofold axis passing through Cu1B-O3B.
Therefore, the difference between the numbers of H2O determines the coordination
geometry of each metal centre. Selected distances and angles are provided on Table 1.
For 2A, the basal plane is formed by trans-coordinated 4-Phpy (Cu1A-N1A 2.028(3) Å)
and trans-coordinated monodentate MeCO2 (Cu1A-O1A 1.984(2) Å). The apical
positions are occupied by two weakly bonding oxygen atoms from H2O molecules
(Cu1A-O3A 2.381(3) Å). This longer distance respect to the basal plane can be
attributed to Jahn-Teller effect. The other O2A atom of the acetate lies at a large
distance (Cu1A····O2A 3.300 Å) and is therefore, uncoordinated. Bond angles are in
the range 85.24(11)°-94.76(11)°. For 2B, 4-Phpy and acetate ligands form the basal
plane (Cu1B-N1B 2.023(3) Å and Cu1A-O1A 1.951(2) Å) and a H2O ligand is in the
6

apical position (Cu1B-O3B 2.222(4) Å). Once again, the uncoordinated O2B atom of
the acetate ligand lies at a long distance (Cu1B····O2B 3.126 Å). Short bond angles are
in the range of 88.18(8)°-94.16(9)° and long ones in the range of 170.77(18)°-
176.36(16)°. All these distances and angles are in good agreement with related acetate-
pyridine compounds [21-28].
The presence of two crystallographic monomeric subunits generates an intriguing
supramolecular structure, in which the coordinated H2O molecules play a key role. Each
subunit interacts exclusively with its symmetry related subunits to generate 1D
supramolecular chains, and each include only 2A subunits or 2B subunits (Fig. 3, up).
Those chains grow in a parallel fashion in the b direction and are stacked alternatively
in the a direction, forming a layered structure. Cu····Cu distance between units in the
same chain is 5.867 Å for both Cu1A····Cu1A and Cu1B····Cu1B. Interlayer
Cu1A····Cu1B distance is 8.361 Å. A similar supramolecular structure is seen in the
closely related compounds {[Cu(2,4-bipy)2(MeCO2)2(H2O)2]·[Cu(2,4-
bipy)2(MeCO2)2(H2O)]} (2,4-bipy= 2,4-bipyridyl) [27] and
{[Cu(stpy)2(MeCO2)2(H2O)2]·[Cu(stpy)2(MeCO2)2(H2O)]} (stpy= trans-4-
styrylpyridine) [28]. These two compounds also contain two crystallographic
independent monomeric subunits, one having an octahedral geometry and the other
having a square pyramidal one, which form independent 1D chain containing only
either octahedral or square pyramidal subunits. Furthermore, intrachain and interlayer
Cu····Cu distances show similar values for all three compounds. Interestingly, for these
two combinations of acetate and pyridine derivative ligands no dimeric structures have
been found in the literature.
The study of each individual chain reveals that their H-bridging interactions are
different. Each monomer 2A has a symmetric quadruple H-bond, involving O1A from
7

the acetate ligand (which is the coordinating oxygen) and H3OB from the H2O molecule
(O3A-H3OB 0.832 Å, O1A····O3A-H3OB 2.849 Å, O1A····H3OB-O3A 2.050 Å,
O1A···H3OB-O3A 160.92ᵒ). Each Monomer 2B forms an asymmetric double bond,
involving O2B from the acetate ligand (note that this is the non-coordinating oxygen)
and H3OC from the H2O molecule (O3B-H3OC 0.830 Å, O2B····O3C-H3OC 2.719 Å,
O2B····H3OC-O3B 1.903 Å, O2B····H3OC-O3B 167.13ᵒ) (Fig. 3, down).
3. Conclusions
Direct reaction of Cu(II) acetate with 4-phenylpyridine (4-Phpy) at room temperature
and alcohol (EtOH or MeOH) and H2O as solvent, allowed the preparation of
monomeric and dimeric compounds. The formation of the monomeric or dimeric
compounds depends on the solvent. When this solvent is alcohol (EtOH or MeOH), the
formation of the paddle-wheel compound (3) is observed, however, when the solvent is
an alcohol:H2O (1:1) mixture, the monomeric compounds (1, 2) are obtained. The
formation of compounds 1 and 2 depends on the alcohol used, MeOH and EtOH,
respectively, as confirmed via PXRD. The three compounds have been fully
characterized, and for the compound 2 the crystal and molecular structure was
determined by X-ray diffraction. The crystal structure reveals the presence of two
independent monomers (2A, 2B). Monomers 2A and 2B differ in the number of H2O
molecules coordinated to the metal, two in the former, and one in the second. In the
crystal packing of this compound, the coordinated H2O molecules play a key role
generating two different 1D chains.
4. Experimental
4.1. General details
Copper(II) acetate monohydrate (Cu(MeCO2)2·H2O), 4-phenylpyridine (4-Phpy)
reagents, methanol (MeOH) and ethanol (EtOH) were purchased from Sigma-Aldrich
8

and used without further purification. All the reactions and manipulations were carried
out in air. Elemental analysis (C, H ,N) were carried out on a Euro Vector 3100
instrument. IR spectra were recorded at the on a Tensor 27 (Bruker) spectrometer,
equipped with and attenuated total reflectance (ATR) accessory model MKII Golden
Gate with diamond window in the range 4000-600 cm-1. PXRD patterns were measured
with Siemens D5000 apparatus using the Cu Kα radiation of 0.15418 nm. Patterns were
recorded from 2θ = 5° to 50ᵒ, with a step scan of 0.02ᵒ counting for 1 s. at each step.
4.2. Synthesis of [Cu(MeCO2)2(4-Phpy)2(H2O)2] (MeCO2 = acetate, 4-Phpy = 4-
phenylpyridine) (1)
To a solution containing 4-phenylpyridine (155 mg, 1.00 mmol) in MeOH (20 mL), a
green solution of Cu(MeCO2)2·H2O (198 mg, 0.99 mmol) in H2O (20 mL) was added.
The resulting light blue solution was left to evaporate at room temperature. When the
solution volume was reduced to 20 mL, a blue crystalline solid appeared; it was filtered,
washed with MeOH:H2O (10 mL) and dried in the air.
1. Yield: 0.316 g (60.45%) (respect to Cu(MeCO2)2·H2O). Elemental Analyses: Calc.
for C26H28N2O6Cu (528.06): C 59.14; H 5.34; N 5.31. Found C 59.08; H 5.23; N 5.12%.
ATR-FTIR (wavenumber, cm-1): 3336(br) [ν(O-H), (H2O)], 1654(m), 1612(s)
[νas(COO)], 1562(s) 1484(m), 1397 (s), 1332(s) [νs(COO)], 1332(m), 1231(w), 1162
(w), 1073(w), 1044(w), 1016(m) [ν(CO)], 931(w), 833(m), 764(m), 727(w), 688(m),
666(m), 623(w).
4.3. Synthesis of [Cu(MeCO2)2(4-Phpy)2(H2O)1.5] (MeCO2 = acetate, 4-Phpy = 4-
phenylpyridine) (2)
To a solution containing 4-phenylpyridine (155 mg, 1.00 mmol) in EtOH (20 mL), a
green solution of Cu(MeCO2)2·H2O (198 mg, 0.99 mmol) in H2O (20 mL) was added.
The resulting light blue solution was left to evaporate at room temperature. When the
9

solution volume was reduced to 20 mL, a blue crystalline solid appeared; it was filtered,
washed with EtOH:H2O (10 mL) and dried in the air. Suitable crystals of 2 for X-ray
diffraction (XRD) single crystal elucidation were obtained via recrystallization of 3 in
an EtOH:H2O mixture.
2. Yield: 0.365 g (71.03%). Elemental Analyses: Calc. for C52H54N4O11Cu2 (1038.07):
C, 60.16; H, 5.24; N, 5.40. Found C 60.24; H 5.07; N 5.33%. ATR-FTIR (wavenumber,
cm-1): 3358(br) ν(OH, H2O), 1591 [νas(COO)], 1567(s), 1483(m), 1393(s) [νs(COO)],
1378(m), 1332 (w), 1221(w), 1072(w), 1038(w), 1016(m) [ν(CO)], 928(w), 832(m),
762(m), 729(w), 690(m), 665(m), 618(w).
4.4. Synthesis of [Cu(MeCO2)2(4-Phpy)]2 (MeCO2 = acetate, 4-Phpy = 4-
phenylpyridine) (3)
To a solution containing 4-phenylpyridine (157 mg, 1.01 mmol) in EtOH (20 mL), a
green solution of Cu(MeCO2)2·H2O (200 mg, 1.00 mmol) in EtOH (20 mL) was added.
The resulting green solution was allowed to evaporate at room temperature. When the
solution volume was reduced to 20 mL, a green crystalline solid appeared; it was
filtered, washed with EtOH (5 mL) and dried in the air.
3. Yield: 0.313 g (92.93%) (respect to Cu(MeCO2)2·H2O). Elemental Analyses: Calc.
for C30H30N2O8Cu2 (673.64): C 53.49; H 4.49; N 4.16. Found C 53.28; H 4.37; N
4.09%. ATR-FTIR (wavenumber, cm-1): 1606(s) [νas(COO)], 1547(w), 1488(m),
1417(s) [νs(COO)], 1344(m), 1225 (w) 1073(w), 1048(w), 1026(w), 1012(m) [ν(CO)],
923(w), 837(m), 759(m), 730(w), 692(m), 679(m), 619(w).
The same reaction has been assayed in MeOH resulting in the formation of the same
compound with similar yields.
4.5. Monomer-Dimer conversion
10

1 to 3: After heating a (107 mg, 0.20 mmols) of 1 for 32 h at 50°C, the blue solid
turned green. Yield: 0.049 g (71.7 %).
2 to 3: Heating compound 2 (65 mg, 0.063 mmols) for 32 h. at 50ᵒC resulted in
the formation of 3 in a quantitative yield.
These conversion processes were confirmed via PXRD. These two transformations
imply both dehydration and sublimation of half of the coordinated 4-Phpy. In a separate
experiment, we confirmed that a sample of pure 4-Phpy in the same conditions
sublimates completely.
4.6. X-ray Crystal Structure of 2
The X-ray intensity data for the crystallographic analysis were measured on a D8
Venture system equipped with a multilayer mono-chromate and a Mo microfocus (λ =
0.71073 Å) at 100 K. For the compound [Cu(MeCO2)2(4-Phpy)2(H2O)2]
[Cu(MeCO2)2(4-Phpy)2(H2O)] (2) a blue prism-like specimen was used. The frames
were integrated with the Bruker SAINT Software package using a narrow-frame
algorithm. Data were corrected for absorption effects using the multi-scan method
(SADABS). The calculated minimum and maximum transmission coefficients (based
on crystal size) are 0.6580 and 0.7454.
The structure was solved using the Bruker SHELXTL Software, package and refined
using SHELX [29]. The final cell constants and volume, are based upon the refinement
of the XYZ-centroids of reflections above 20 σ(I). Crystal data and relevant details of
structure refinement are reported in Table 2. Complete information about the crystal
structure and molecular geometry is available in CIF format as Supporting Information.
Molecular graphics were generated Mercury 3.6 software [30,31]. Color codes for all
molecular graphics: orange (Cu), blue (N), red (O), grey (C), White (H).
11

Appendix A. Supplementary material
CCDC 1543398 contains the supplementary crystallographic data for 2. These data can
be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from
the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ,
UK; fax: (+44) 1223-336-033; or e-mail:deposit@ccdc.cam.ac.uk.
IR spectra of the compounds 1-3 are presented. PXRD spectra of the compounds 1-3 are
presented.
Acknowledgements
This work was financed by the Spanish National Plan of Research MAT2015-65756-R
and by 2014SGR260 and 2014SGR377 projects from the Generalitat de Catalunya. J. S.
also acknowledges the Universitat Autònoma de Barcelona for his pre-doctoral grant.
12

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Table 1
Selected bond lengths (Å) and bond angles (º) values for (2A) and (2B). The estimated
standard deviations (e.s.d.s.) are shown in parentheses.
Molecule A
Bond lengths (Å)
Cu(1A)-O(1A)
Cu(1)-N(1A)
1.984(2)
2.028(3)
Cu(1A)-O(3A)
2.381(3)
Bond angles (º)
O(1A)-Cu(1A)-O(1A)#1 180.0
O(1A)-Cu(1A)-N(1A)#1 88.11(11)
N(1A)-Cu(1)-O(3A)#1
O(1A)-Cu(1A)-O(3A)
N(1A)-Cu(1A)-O(3A)
85.24(11)
86.80(10)
94.76(11)
O(1A)-Cu(1A)-N(1A)
91.89(11)
N(1A)#1-Cu(1A)-N(1A) 180.0
O(3A)#1-Cu(1A)-O(3A) 180.0
O(1A)-Cu(1A)-O(3A)#1 93.20(10)
Molecule B
Bond lengths (Å)
Cu(1B)-O(1B)
Cu(1B)-N(1B)
Bond angles (º)
1.951(2)
2.023(3)
Cu(1B)-O(3B)
2.222(4)
O(1B)-Cu(1B)-O(1B)#2 176.36(16)
O(1B)-Cu(1B)-N(1B)#2 89.34(11)
N(1B)#2-Cu(1B)-N(1B)
O(1B)-Cu(1B)-O(3B)
N(1B)-Cu(1B)-O(3B)
170.77(18)
88.18(8)
94.61(9)
O(1B)-Cu(1B)-N(1B)
90.95(11)
#1 = -x+1, -y, -z+1; #2 = -x+1, y, -z+1/2
16

Table 2. Crystallographic data for [Cu(MeCO2)2(4-Phpy)2(H2O)2] [Cu(MeCO2)2(4-
Phpy)2(H2O)] (2).
Formula
C52H54N4O11Cu2
1038.07
100(2)
0.71073
Monoclinic, C2/c
Formula Weight
Temperature (K)
Wavelength (Å)
System, space group
a (Å)
25.181(2)
b (Å)
5.8668(5)
c (Å)
30.879(3)
α (º)
90
β (º)
94.496(4)
γ (º)
90
U (Å 3) / Z
Dcalc (g cm-3) / μ (mm-1)
F(000)
4547.7(7) / 4
1.516 / 1.005
2160
0.279x0.075x0.063
-31≤h≤31,
-7≤k≤7,
Crystal size (mm3)
hkl ranges
-38≤l≤38
2θ Range (º)
Reflections
2.173 to 26.440
38487/4682
[R(int)=0.0570]
99.9
Semi-empirical
0.7454 and 0.6580
4682/4/325
1.279
collected/unique/ [Rint]
Completeness to θ (%)
Absorption correction
Max. and min. trans.
Data/restrains/parameters
Goodness-of-fit on F2
Final R indices [I>2σ (I)]
R1 = 0.0542, wR2 =
0.1200
R indices (all data)
R1 = 0.0605, wR2 =
0.1223
Extinction coefficient
Largest diff. peak and
hole (e Å-3)
n/a
+0.709, −1.441
17

Figure Captions
Figure 1 PXRD patterns of 1 (top), 2 (middle) and 3 (bottom).
Figure 2 Monomers 2A and 2B, and their corresponding numbering scheme for
relevant atoms. Hydrogens are omitted for the sake of clarity.
Figure 3 View of the stacking of Monomers 2A and 2B along the a axis (up). Detailed
view of the H-bonding interactions in the individual chains (down).
18

Scheme 1
19

Figure 1 Experimental PXRD patterns of 1 (top), 2 (middle) and 3 (bottom).
20

Figure 2 Monomers 2A and 2B, and their corresponding numbering scheme for
relevant atoms. Hydrogens are omitted for the sake of clarity.
21

Figure 3 View of the stacking of Monomers 2A and 2B along the a axis (up). Detailed
view of the H-bonding interactions in the individual chains (down).
22

Graphical abstract
Synopsis
Three complexes with copper(II) acetate and 4-phenylpyridine (4-Phpy), two
monomeric [Cu(MeCO2)2(4-Phpy)2(H2O)x] (x = 2 (1), 1.5 (2)) and one dimeric
[Cu(MeCO2)2(4-Phpy)]2 were prepared and characterized. The obtaining of the
compounds depends on the solvent used in the synthesis. The crystal structure of
compound 2 contains two crystallographic independent mononuclear units. Each
mononuclear unit forms an independent 1-D chain.
23