Structural insights into the usage of carboxylate ions as molecular pins

Article abstract of DOI:10.1016/j.poly.2017.07.011

Two series of new isostructural coordination compounds containing cobalt, nickel, copper butyrates (butyr) or isobutyrates (ibutyr) and 1,10-phenanthroline (phen), of general formulas [M(phen)₃]²⁺·2(butyr^?)·11H₂O and [M(phen)₃]²⁺·2(ibutyr^?)·14H₂O, were synthesized in water solutions and characterized by X-ray crystallography, IR, UV–Vis and fluorescence spectroscopy, elemental and thermal analysis. The carboxylate anions are located in an outer coordination sphere, which is a unique phenomenon in case of ibutyr coordination compounds. The studied compounds exhibit layered packing in crystal net. The “aqueous layers” consist of water molecules and carboxylate groups of carboxylate anions, assembled via hydrogen bonds to the two dimensional supramolecular networks containing multiple different cyclic motifs. Coordination units together with aliphatic ends of carboxylate anions form the “coordination moieties layers”, which are internally connected via π?π and C–H?π intermolecular interactions. The carboxylate anions function as supramolecular linkers between these layers and allow pinning them together. The spectroscopic and thermal properties have been discussed and correlated with molecular structures of the studied compounds. Due to placement of carboxylate anions out of coordination moieties, the presented compounds can be ideal standards in spectroscopic determinations of coordination type of butyr and ibutyr ions in coordination compounds. The thermal analyses of the studied compounds revealed the possibility of formation of dihydrate forms, and such dihydrated compounds cannot be produced in direct synthesis performed in aqueous media. In properly set environment the studied compounds can be thermally converted to micro- and nanoparticles of respective metal oxides.

Full text of DOI:10.1016/j.poly.2017.07.011

Accepted Manuscript
Structural insights into the usage of carboxylate ions as molecular pins
Marcin Swiatkowski, Rafal Kruszynski
PII:
S0277-5387(17)30494-1
DOI:
http://dx.doi.org/10.1016/j.poly.2017.07.011
POLY 12747
Reference:
Polyhedron
To appear in:
Received Date:
Revised Date:
Accepted Date:
4 April 2017
15 July 2017
17 July 2017
Please cite this article as: M. Swiatkowski, R. Kruszynski, Structural insights into the usage of carboxylate ions as
molecular pins, Polyhedron (2017), doi: http://dx.doi.org/10.1016/j.poly.2017.07.011
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Structural insights into the usage of carboxylate ions as molecular pins
Marcin Swiatkowski, Rafal Kruszynski
Institute of General and Ecological Chemistry
Lodz University of Technology, Zeromskiego 116, 90-924, Lodz, Poland
Abstract
Two series of new isostructural coordination compounds containing cobalt, nickel, copper butyrates
or isobutyrates (ibutyr) and 1,10-phenanthroline (phen), of general formulas
(butyr)
[M(phen)3]2+∙2(butyr)∙11H2O and [M(phen)3]2+∙2(ibutyr)∙14H2O, were synthesized in water solutions and
characterized by X-ray crystallography, IR, UV-Vis and fluorescence spectroscopy, elemental and thermal
analysis. The carboxylate anions are located in an outer coordination sphere, which is a unique phenomenon in
case of ibutyr coordination compounds. The studied compounds exhibit layered packing in crystal net. The
“aqueous layers” consist of water molecules and carboxylate groups of carboxylate anions, assembled via
hydrogen bonds to the two dimensional supramolecular networks containing multiple different cyclic motifs.
Coordination units together with aliphatic ends of carboxylate anions form the “coordination moieties layers”,
which are internally connected via π•••π and C—H•••π intermolecular interactions. The carboxylate anions
function as supramolecular linkers between these layers and allow pinning them together. The spectroscopic and
thermal properties have been discussed and correlated with molecular structures of the studied compounds. Due
to placement of carboxylate anions out of coordination moieties, the presented compounds can be ideal standards
in spectroscopic determinations of coordination type of butyr and ibutyr ions in coordination compounds. The
thermal analyses of the studied compounds revealed the possibility of formation of dihydrate forms, and such
dihydrated compounds cannot be produced in direct synthesis performed in aqueous media. In properly set
environment the studied compounds can be thermally converted to micro- and nanoparticles of respective metal
oxides.
Keywords: 1,10-phenanthroline; cobalt; nickel; copper; nanoparticles
1. Introduction
Nowadays, coordination chemistry is one of the most important field of chemistry. It gives endless
possibilities to create metal and semimetal coordination compounds with organic and inorganic molecules [1, 2,
3, 4, 5, 6, 7, 8, 9, 10, 11, 12]. Structural investigations allow determination of correlation between the structure
of compounds and their physicochemical properties. Such relationships are the basis of intentional application of
coordination compounds in practice [13, 14, 15]. In property-designed synthesis, the most popular are N-donor
ligands. These ligands are often utilized solely (or with O-donor ligands) in construction of structurally variable
coordination compounds. 1,10-Phenanthroline (phen) is a model representative of this group of ligands. It
possesses two close deshielded nitrogen atoms, thus it is a perfect bidentate chelating ligand [16, 17, 18]. The
phen typically acts as a bidentate ligand. Few compounds with chelating-bridging phen were synthesised, but
this coordination mode is extremely rare [19]. The most popular metal : phen stoichiometry in an inner
coordination sphere of mononuclear coordination compounds is 1:1 (2157 compounds structures deposited in
1

Cambridge Structural Databes [20]), slightly less popular stoichiometry is 1:2 (1299 compounds structures), and
next are the stoichiometries: 1:3 (563 compounds structures), 1:4 (9 compounds structures), and 1:5 (1
compound structure) [21].
Phen is employed willingly in many fields of science and industry. It is commonly used in analytical
chemistry as an indicator in quantitative determination of metal cations (e.g. in spectrophotometric determination
of iron(II) [22]). Some coordination compounds with metal : phen stoichiometry 1:1, like [MgSO4(H2O)3(phen)]
and [ZnBr2(phen)], are efficient luminescent materials [23, 24]. These compounds absorb radiation from UV
region and exhibit strong blue or green fluorescence, thus can be employed as perfect UV sensors. Recently,
compounds with phen have been widely studied in terms of DNA interactions and cytotoxicity [25].
Coordination compounds of copper(II) with phen and other ligands possess anti-proliferative activity against
cancer [26]. Due to catalytic activity toward reactive oxygen species, such compounds are able to induce
breakage of DNA strands in aqueous solution without presence of any external reducing factors. Palladium(II)
compounds with phen are cytotoxic against chronic myelogenous leukemia cells [27] while rhodium(III) and
iridium(III) mononuclear compounds with phen derivatives exhibit anti-proliferative activity toward Jurkat
leukemia cells [28]. There is also possible to reduce, or even completely inhibit, a growth of many cell lines of
bacteria and fungi with usage of phen coordination compounds. The [Cu(SAla)phen]H2O (SAla –
salicylidenealanine) manifests strong antibacterial activity against i.a. Salmonella typhi, and antifungal activity
against i.a. Candida albicans [29]. Coordination compounds of phen and phen derivatives can be used
effectively as substrates in the single precursor method for production of metal oxide nanoparticles [30, 31, 32].
The current work deals with the synthesis, structure, spectroscopic and thermal properties of six new
coordination compounds of cobalt, nickel and cooper butyrates/isobutyrates with phen (of which compounds
with the same anions are isostructural), of general formulae [M(phen)3]2+∙2(butyr)∙11H2O and
[M(phen)3]2+∙2(ibutyr)∙14H2O (M = Co, Ni, Cu, respectively for compounds 1, 2, 3 containing butyr anion and
for compounds 4, 5, 6 containing ibutyr anion), possessing less typical 1:3 metal : phen stoichiometry. The
possibility of conversion of compounds 1-6 into nanoparticles (via single precursor method) is also presented
and discussed. The butyr and ibutyr anions are long enough for possessing well separate hydrophobic properties
(at the aliphatic end) and hydrophilic properties (at the carboxylate end), and thus they can be used for
assembling of the supramolecular layers constructed from purely hydrophobic (M(phen)3 in studied case) and
hydrophilic (H2O) moieties.
2. Experimental
2.1. Synthesis
All reagents were analytical grade. Butyric acid (butyrH) and isobutyric acid (ibutyrH) were obtained
from Sigma-Aldrich, and all other chemicals were purchased from POCh S.A. The analytical grade water was
obtained from improved drinking water via combined reverse osmosis and ion exchange processes.
2.1.1. Preparation of butyrate and isobutyrate salts
The aqueous solutions of Co(butyr)2, Ni(butyr)2, Cu(butyr)2, Co(ibutyr)2, Ni(ibutyr)2 and Cu(ibutyr)2
were synthesized in reaction between appropriate metal oxide and butyrH or ibutyrH. 4.2 mmol of each metal
oxide was suspended in 100 cm3 of water, and then 8 mmol of 99% butyrH (0.74 cm3, d = 0.958 g/cm3 in 25°C)
or 99% ibutyrH (0.75 cm3, d = 0.95 g/cm3 in 25°C) was added. Such 6 mixtures (each metal oxide with each
acid) were being heated at 100°C under reflux for 3h. Next, the suspensions were filtered in order to remove
2

excess of metal oxide. The concentrations of Co2+, Ni2+ and Cu2+ in resulting filtrates were determined via edta
titration in presence of pyrogallol red, pyrocatechol violet and 1-(2-pyridylazo)-2-naphtol, respectively for the
above mentioned cations [33].
2.1.2. Preparation of coordination compounds
The coordination compounds 1-6 were prepared by reaction of appropriate butyrate or isobutyrate salts
with 1,10-phenanthroline in molar stoichiometry of reagents 1:3. 3 mmol of phen were dissolved in mixture of
methanol and water (5 + 5 cm3) and added dropwise to every above described water solutions containing 1 mmol
of appropriate salt. The reaction mixtures were being stirred vigorously at room temperature for 20 minutes. The
solutions were left to crystallize. After one month, the grown colour crystals (brown – cobalt compounds,
burgundy – nickel compounds, blue – copper compounds) were filtered off and dried in air.
2.1.3. Preparation of micro- and nanoparticles of metal oxides
The coordination precursors 1-6 were converted to micro- and nanoparticles of respective metal oxides
via controlled thermal decomposition (carried out in corundum crucibles placed in a muffle furnace, in air
atmosphere). Two experiments were performed. In the first one (E1), samples of 1-6 were heated with heating
rate 5 °C min-1 to temperature of formation of respective metal oxide (determined individually for each
coordination compound, on the basis of thermal analyses, i.e. 500, 500, 520, 490, 490 and 550 °C respectively
for 1-6). In the second one (E2), samples were placed in a furnace initially heated to the determined temperature
of formation of respective metal oxide.
2.2. Crystal structure determination
Crystals were mounted in turn on the KM-4-CCD automatic diffractometer equipped with the CCD
detector, and used for data collection. X-ray intensity data were collected with graphite-monochromated CuK1
radiation (λ = 1.54178 Å) at 100.0(1) K, with ω scan mode. Lorentz, polarization, decay and numerical
absorption corrections were applied [34]. The structures were solved by partial structure expansion procedure.
All non-hydrogen atoms were refined anisotropically using full-matrix, least-squares method on F2. All
hydrogen atoms were found on the difference Fourier syntheses and were refined in riding model. Isotropic
displacement factors of hydrogen atoms were equal to 1.2 and 1.5 times a value of equivalent displacement
factor of patent carbon and oxygen atoms, respectively. Carbon-bonded hydrogen atom positions were idealized
after each cycle of refinement. The SHELXT [35], SHELXL [36], and SHELXTL [37] programs were used for
all calculations. Atomic scattering factors were those incorporated in the computer programs. The details
concerning crystal data, refinement and selected structural data of compounds 1-6 are given in Tables 1-4. One
of butyr anions in compound 2 is disordered over two positions with 0.59 : 0.41 participation of domains. It
affects the number of water molecules located in the crystal net of compound 2 (in comparison to compound 1
and 3), because water molecules share the positions of the crystal net with the minor disordered domain of butyr
anion. Some displacement ellipsoids of outer coordination sphere species exhibit prolation or oblation effects,
probably as a result of disorder. Introduction of disorder models (containing two or three domains) leads to
worsening of refinement parameters as well some instability of refinement. Consequently, it can be assume that
the disorder is dynamical in character or is a multipositional one, and thus these models were not applied in the
final refinement. In case of compounds 1 and 3, above mentioned effects lead to worse quality of structure
determination, but this fact did not affect the unambiguity of the structural determinations themselves. The
further details on the structures refinement are given in the supplementary materials (paragraph S2.2).
3

2.3. Other measurements
The IR spectra of the studied compounds were recorded on the Jasco FT/IR 6200 spectrophotometer, in
the spectral range 4000 – 400 cm-1, as KBr pellets. The UV-Vis diffuse reflectance spectra were recorded on the
Jasco V-660 spectrophotometer, in spectral range 200 – 800 nm, using BaSO4 as a standard with 100%
reflectance. The three dimensional fluorescence spectra were recorded on the Jasco FP-6300 spectrofluorometer,
with solid samples directed at the angle of 30° to incident beam. Data pitch and bandwidth were 1 nm on both
monochromators. The thermal analyses were carried out in the TG/DTA (SETSYS-16/18) thermoanalyser
coupled with the mass spectrometer (QMS-422; ThermoStar Balzers Instruments). The samples were heated in
corundum crucibles up to 1000 °C at a heating rate of 5°C•min-1 in air flow. The final products of decomposition
were confirmed by X-ray powder diffraction (XRPD) using the Powder Diffraction File [38] or literature data.
The XRPD patterns were measured in reflection mode on the XPert PRO X-ray powder diffraction system,
equipped with the Bragg-Brentano PW 3050/65 high resolution goniometer and the PW 3011/20 proportional
point detector. The CuK1 radiation was used. The patterns were measured at 291.0(2) K in range 2 – 90° with
the narrowest beam attenuator. Diamond powder was used as an internal reference. The surface morphologies of
micro- and nanoparticles of metal oxides were characterized by the scanning electron microscope with energy
dispersive X-ray spectrometer (SEM-EDS, HITACHI S-4700, EDS Thermo NORAN). Elemental analyses were
carried out using the Vario EL III CHNOS Elemental Analyzer (C, H, N, O). Cobalt(II), nickel(II) and copper(II)
contents were determined by titration with edta, as described in paragraph 2.1.1. [33]. Elemental analyses for
coordination compounds [Calc./Found (%)]: (1) C44H60CoN6O15 C 54.36/54.10; H 6.23/6.51; Co 6.06/5.92; N
8.65/8.78; O 24.69/24.82; (2) C44H58.35N6NiO14.18 C 55.23/54.89; H 6.15/6.49; N 8.78/8.44; Ni 6.13/5.78; O
23.71/24.73; (3) C44H60CuN6O15 C 54.11/54.02; H 6.20/6.31; Cu 6.51/6.20; N 8.61/8.74; O 24.57/24.60; (4)
C44H66CoN6O18 C 51.50/51.59; H 6.50/6.45; Co 5.74/5.51; N 8.19/8.28; O 28.07/28.14; (5) C44H66N6NiO18
C
51.51/51.57; H 6.50/6.41; N 8.19/8.24; Ni 5.72/5.49; O 28.07/28.21; (6) C44H66CuN6O18 C 51.27/51.21; H
6.47/6.59; Cu 6.17/5.97; N 8.16/8.10; O 27.94/27.90.
3. Results and discussion
The reactions of butyr and ibutyr salts with phen lead to formation of two isostructural series of
compounds, with general formulae: [M(phen)3]2+∙2(butyr)∙11H2O and [M(phen)3]2+∙2(ibutyr)∙14H2O (Fig. 1).
The isostructurality among coordination compounds is observed due to i.a. replacement of a metal cation for
another one, with close ionic radius. It is possible for the presented coordination compounds, since the ionic radii
of cobalt(II), nickel(II) and copper(II) are very similar (0.74, 0.69 and 0.73 Å, respectively [39]). The applied in
the synthesis 1:3 metal : ligand stoichiometry is retained in the crystal structures of obtained compounds. The
inner coordination spheres of discussed compounds are created by a central atom and three bidentate chelating
molecules of phen. In each case, the coordination polyhedron is slightly distorted octahedron [40] (Table 2). A
weak compressive Jahn-Teller effect observed in the copper compounds causes that distortions in them are
slightly larger than in the cobalt and nickel compounds. The central atoms of ibutyr coordination compounds are
located at the special position e of the C2/c space group (with site symmetry 2 and multiplicity 4), whereas all
atoms of butyr coordination compounds occupy the general positions. Despite that, the coordination units of both
compounds groups are quite similar (Fig. S2). Therefore, the existence of compounds in different space groups
4

(P-1 and C2/c) is not a consequence of differences in phen positions around the central atom. This difference
results from the existence of the different isomer of anion. The structural differences between anions cause
presence of different number of water molecules in the outer coordination sphere (even and odd) and
subsequently lead to their less symmetrical location in the butyr compounds.
The correctness of assignment of the central atoms formal oxidation states was confirmed with usage of
the bond-valence method. The bond valences were computed as ij = exp[(Rij-dij)/b] [41, 42], where Rij is the
bond-valence parameter (in the formal sense Rij can be considered as a parameter equals to the idealized single-
bond length between i and j atoms for given b) and b was taken as 0.37 Å [43, 44]. The RCo-N, RNi-N, and RCu-N,
were re-determined for coordination compounds, as it was previously described [45, 46, 47], and their values
were 1.727, 1.674 and 1.752, respectively. The computed bond valences are collected in Table 2. The computed
total valences of central atoms (BVS) are very close to the expected value of +2 (formal oxidation state of
metal), and in each case, a deviation of BVS is smaller than value of 0.25 - 0.30 v.u. [48], which exceeding could
indicate mistakes in an interpretation of the compound structure or in a charge of an ion. The largest deviations
are noted for the copper coordination compounds (2.174 and 2.181 v.u. respectively for 3 and 6), due to a weak
compressive Jahn-Teller effect. Two of three chelating molecules of phen coordinate stronger by one of two
nitrogen-donor atoms (phen ligands coordinate asymmetrically to the central atom), as a result of rigid restrains
imposed by stiff chelating ligand. Consequently, one coordination bond has expected strength, but second of
them is significantly stronger (by about 0.1 v.u), what causes positive deviation of BVS.
All butyr and ibutyr ions are located in the outer coordination sphere. It is a unique phenomenon for
ibutyr, not structurally proved in literature, because in coordination compounds (with determined crystal
structures) ibutyr always acts as a ligand directly coordinating a metal ion. For butyr, there are only three
compounds reported in Cambridge Structural Database [20], in which this anion is placed out of coordination
moieties, i.e. catena(tetra-aqua-(μ2-butyrato)-magnesium butyrate) [49], (μ2-butanoato-O,O')-monoaqua-
ethanolato-bis(1,2-bis(salicylaldiminato)ethane)-di-manganese
butyrate
[50],
heptatriaconta-ammonium
tetracosakis(butyrate) molybdate hydrate [51]. Apart from carboxylate anions, there are 11 and 14 water
molecules in the outer coordination sphere, respectively for butyr and ibutyr coordination compounds. As a
consequence of different properties of species forming the compounds (coordination moieties, anions and water
molecules), two layers are created in the crystal nets: the “aqueous layer” and the “coordination moieties layer”,
containing respective species (Fig. 2). Due to the content, the layers can be considered as hydrophilic (rich in O-
H hydrogen bond donors and O hydrogen bond acceptors) and hydrophobic (rich in  electrons and C-H groups).
The carboxylate anions connect these layers, because the carboxylate groups take part in formation of hydrogen
bonds with water molecules (hydrophilic end of anion) and the aliphatic groups are located in the “coordination
moieties layer” (hydrophobic end of anion). The water molecules and carboxylate anions are assembled to the
two dimensional supramolecular networks via hydrogen bonds (Table 3). These bonds form different multiple
2
3
6
6
3
6
3
cyclic motifs, characterized by: N2R4 (8), N3R3 (8), N3R6 (12), N3R6 (16), N4R4 (8), N4R8 (16), N5R5 (10),
5
4
5
4
N5R5 (12), N6R6 (12), N6R6 (12) graphs for butyr compounds (respectively 1-10 in Fig. 3a), and N2R4 (8),
3
6
4
4
N3R3 (8), N3R6 (12), N5R5 (10), N5R5 (12) for ibutyr compounds (respectively 1-5 in Fig. 3b). According to
classification of the extended water motifs [52], these existing in the studied compounds can be classified as the
infinite layer motifs in two dimensions and can be described as L4(5)4(6)5(5)5(6)6(6)6(7)7(9)8(12)10(10) and
L4(6)5(6)5(7)6(8)7(8), respectively for butyr and ibutyr compounds. Noteworthy is the fact that, such motifs
5

have been not registered for any structurally characterized compound, and they can be expressed as the six petals
flower-like motifs (Fig. 3).
The “coordination moieties layer” is stabilized in both compounds groups via π•••π and C—H•••π
intermolecular interactions (Table 4). In the butyr compounds, only one phen ligand of the coordination unit
takes part in π•••π stacking interactions. This phen molecule associates with the alternatively orientated
equivalent phen molecule by two of three delocalized rings (stacking type XII [53], Fig. S7a). The formed π•••π
supramolecular dimers of the coordination units interact indirectly with other ones through the butyr anions.
Each carboxylate ion, located between two phen molecules of two coordination entities, associates with them by
C—H•••π interactions (Fig. S7a). In consequence, the two dimensional supramolecular net is formed. The
intermolecular interactions array is significantly different for the ibutyr compounds. The π•••π interactions are
formed by two phen molecules of each coordination unit. Only carbon (C6) rings take part in association
(stacking type XIII, Fig. S7b). Therefore, the coordination entities are assembled to the parallel one dimensional
chains, extending along crystallographic [001] axis. The ibutyr anions, in opposition to the butyr ones, do not act
as supramolecular linkers between the coordination entities. Each ibutyr anion associates via C—H•••π
interactions with only one phen molecule (Fig. S7b).
The isostructurality resulting from replacement of a metal cation causes that the IR spectra of studied
butyr as well as ibutyr coordination compounds are almost perfectly identical within each group, in investigated
range of wavenumbers (Table 5, Fig. S3). The large number of water molecules in crystal structures of both
compounds groups is visible in the IR spectra of these compounds as two typical bands originating from OH
stretching and bending vibrations. They fall over 3100 cm-1 (strongly broadened band as a result of different
environment of each water molecule and consequently different energies of specific oscillators) and about 1650
cm-1, respectively. In comparison to the spectrum of pure phen, the typical for chelating molecules blue shifts of
bands corresponding to CC and CN stretching vibrations are observed [23, 24, 53]. The spectra of the studied
compounds exhibit also a set of bands characteristic for aliphatic parts of carboxylate anions, including
stretching and various bending vibrations of CH and CC bonds. The asymmetric (νas) and symmetric (νs)
stretching vibrations of carboxylate groups reflect in strong bands at about 1550 (cobalt and nickel compounds)
and 1560 (copper compounds) for the former ones, and 1425 cm-1 (all compounds) for the latter ones. The
location of carboxylate anions in outer coordination sphere results in shift of the νas bands toward lower
frequencies (in comparison to pure salts). The carboxylate group participates only in hydrogen bonds with water
molecules, therefore it possesses larger oscillation freedom (the energy required to excite vibrations is lower in
comparison to pure salts, in which carboxylate anions coordinate directly to central atoms) [54]. Due to such
location of carboxylate anions, the studied compounds can be ideal standards in spectroscopic determinations of
coordination type of butyr and ibutyr ions in coordination compounds. This can be achieved with usage of the Δν
parameter, i.e. the difference between wavenumbers of νas and νs of carboxylate group. The Δν parameter is
commonly used to distinguish a functionality and a denticity of carboxylate groups, but for correct usage a
reference compounds with unambiguously determined structure (via other method) must be known [55, 56]. It
must be outlined that, although the Δν is the same for cobalt and nickel compounds (127 and 126 cm-1,
respectively for butyr and ibutyr compounds), it is different for copper compounds (138 and 135 cm-1, as above).
This indicates that the comparison of the Δν values must also cover a consideration of central atoms and should
not be limited to a consideration of sole carboxylate anion. The determined values are distinctly different than
6

values calculated for butyr and ibutyr anions acting as bidentate chelating ligands, e.g. Δν values for (butanoato)-
bis(N-(pyridin-2-yl)pyridin-2-amine)-cobalt(II) chloride [57], (butanoato)-bis(N-(pyridin-2-yl)pyridin-2-amine)-
nickel(II) chloride [57], (2-methylpropanoato)-bis(1,10-phenanthroline)-copper(II) nitrate dihydrate [58], are
164, 166, and 167 cm-1, respectively. The Δν values for butyr and ibutyr located in an inner coordination sphere
are larger than Δν values determined for these anions located in an outer coordination sphere by about 30-40
cm-1. Such difference is large enough for determination of ligand location in an outer coordination sphere on the
basis of IR data. It also proves a usefulness of the studied compounds in establishing of coordination type of
butyr and ibutyr ions via IR spectroscopy.
The solid state UV-Vis spectra of the studied compounds contain several absorption maxima (Table 6,
Fig. S4). In investigated wavelength range, solid state phen exhibits five absorption maxima at 214, 253, 294,
324, 335 nm corresponding to π → π* (first two maxima) and n → π* (last three maxima) transitions [24], which
are also present in the spectra of 1-6. Generally, these maxima are red-shifted in all cases, due to stronger π•••π
stacking interactions in pure phen (than in coordination compounds) in case of π → π* transitions [23], and due
to participation of nitrogen lone electron pairs of phen in coordination bonds, what leads to decrease the energy
as well as the population of n → π* transitions [24]. The intense colour of the studied compounds originates
from d-d transitions. Due to analogous distorted octahedral geometry of coordination polyhedra, the same
maxima are observed in the spectra of compounds of the same cation. Three transitions are expected for both
4
4
4
4
4
cobalt [4T1g(F) → T2g(P) (ν1), T1g(F) → A2g(F) (ν2), T1g(F) → T1g(P) (ν3)] and nickel compounds [3A2g
→
3
3
3
3
3T2g(F) (ν1), A2g → T1g(F) (ν2), A2g → T1g(P) (ν3)] [59]. The registered spectra of cobalt compounds contain
solely maximum corresponding to the highest energy d-d transition (ν3). The second one (ν2), which is forbidden
two-electron transition and is usually observed as a weak shoulder maximum [60], is not present in the spectra of
the studied compounds. The lowest energy transition (ν1) exists in near-IR region (1078 nm [61], 1248, 1256 nm
[62]), so it is out of investigated range. In case of nickel compounds, the ν3 and ν2 transitions are observed as two
maxima in visible and slightly above visible region, respectively. Similarly to cobalt compounds, the ν1
transition is also outside of the measurement region (985 nm [63], 967 nm [61], 998, 1086, 1135, 1256 nm [62]).
2
Blue colour of copper compounds is due to the broad absorption maximum at about 680 nm. The Eg → 2T2g(F)
transition is expected in octahedral copper compounds, but due to weak compressive Jahn-Teller effect in 3 and
2
2
2
2
2
2
6, it splits into three transitions B1g → A1g (ν1), B1g → B2g (ν2), B1g → Eg (ν3). All these e transitions are
closely similar in energy, therefore they exist in studied spectra as single broad maximum [64, 65]. The maxima
in 400 – 460 nm range originates from ligand – metal charge transfer transitions (LMCTs). The LMCTs are not
observed in copper compounds, what was previously reported for [Cu(phen)3]2+ compounds [66, 67, 68].
The fluorescence properties of pure phen make it suitable for constructing of fluorescent materials. The
pure phen exhibits three emission maxima at 363, 381 and 431 nm for 341, 345 and 371 nm excitation
wavelengths, respectively (Fig. S5a) [24]. The studied compounds do not possess even weak fluorescence
properties in solid state (Fig. S5b) as a result of vibrational relaxation blockage of exited state by the stiff,
strongly restrained and sterically hindered [M(phen)3]2+ system.
The thermal analyses of 1-6 revealed the same decomposition pathway for all compounds, what can be
expected due to analogous structures of butyr and ibutyr compounds (Table 7, Fig. S6, Scheme S1). As a result
of large number of water molecules in an outer coordination sphere, the studied compounds are not very stable
and start to decompose at 30-40°C. The first stage of decomposition is the endothermic dehydration during
7

which 9 and 12 water molecules (respectively for butyr and ibutyr compounds) are evaporated, what causes that
two water molecules remain in structure of each compound. It means that all studied compounds can also exist as
dihydrates, but the obtainment of such dihydrate form is impossible via standard crystallization. The IR spectra
of these dihydrates suggest that remaining water molecules are bonded to carboxylate anions via O-H•••O
hydrogen bonds. The dihydrates are stable up to 175-185 °C, and then the second decomposition stage begins.
This stage is a combination of simultaneous removal of remaining two water molecules and combustion of
carboxylate anions. The strong exothermic process of phen decomposition starts at about 360-400 °C, but only in
case of 1, 4 and 6, it is possible to distinguish the border between the second and the third decomposition stage.
For the rest compounds, these two stages are slightly overlapped. In all cases, the final decomposition product is
the respective metal oxide, stable to the highest measured temperature (1000°C).
The controlled thermal conversion of coordination precursors 1-6 leads to formation of bulky or porous
particles (of micro and nano size, Fig. 4 and 5) of cubic NiO/CoO (rock salt structure, a = b = c = 4.178 Å (for
NiO) and 4.263 Å (for CoO), Z = 4, space group Fm-3m, No. 225) and of monoclinic CuO (a =4.684 Å, b =
3.423 Å, c = 5.129 Å,  = 99.54(1)° Z = 4, space group C2/c, No. 15). The formed particles exhibited significant
differences in morphology and/or size. These differences originate from three factors: structure of precursors,
structure of products and thermal conversion parameters. The cubic oxides form large plates and prisms
composed of small agglomerated spherical nanoparticles. These agglomerates contain nano-sized crack and
pores. The pores are better shaped and more regular in case of oxides produced from compounds containing
butyr ions, as a result of deeper penetration of the “coordination moieties layer” by these ions and stronger
“inflating” of the particles during decomposition. The same phenomenon is responsible for formation of larger
pores upon instant heating of sample (experiment E2, paragraph 2.1.3.). The monoclinic oxide exists in form of
nanospheres agglomerated into complex 3D architectures. The instant heating of sample (E2) leads to larger
agglomeration than observed for slow heating (experiment E1, paragraph 2.1.3.). The E2 nanoparticles form
smooth microstructures, whereas the E1 nanoparticles are assembled into protruding micrograins. Similarly to
cubic oxides and due to the same reasons, the monoclinic oxide created from the compound containing butyr
ions is dispersed at larger degree than observed for oxide based on ibutyr compounds. Combination of slow
heating (E1) and structure of precursor based on an ibutyr ion allows formation of raspberry-like microentities
(Fig. 5(6_CuO_E1) and Fig. S8).
4. Conclusions
1,10-Phenanthroline with cobalt, nickel, copper butyrates and isobutyrates forms two groups of
isostructural coordination compounds (of general formulas [M(phen)3]2+∙2(butyr)∙11H2O and
[M(phen)3]2+∙2(ibutyr)∙14H2O), as a result of direct reactions between mentioned species in an aqueous medium.
The existence of a different isomer of the anion and consequently different number of water molecules in an
outer coordination sphere subsequently leads to less symmetrical location of them in butyr compounds and
forces adoption of different space groups (P-1 and C2/c, respectively for butyr and ibutyr compounds). The
layered crystal structures of studied compounds are stabilized via hydrogen bonds network in the “aqueous
layer” (hydrophilic one), and via π•••π interactions in the “coordination moieties layer” (hydrophobic one).
Additional connection between layers is provided by carboxylate anions, which interact with both layers via
hydrogen bonds and C—H•••π interactions, respectively. Consequently, carboxylate anions function as
8

supramolecular linkers between these layers and allow pinning them together. The studied compounds can be
ideal standards in spectroscopic determination of a coordination type of butyr and ibutyr in coordination
compounds, due to location of such carboxylates in an outer coordination sphere. The determined Δν parameter
for non-coordinating butyr and ibutyr anions is about 127 cm-1 for cobalt and nickel compounds, and 137cm-1 for
copper compounds. The IR and UV-Vis spectra contain bands and maxima expected for chelating phen
molecules. The octahedral geometries of coordination polyhedra result in appropriate maxima in visible region.
A weak compressive Jahn-Teller effect causes considerable spectral changes in the Vis region of UV-Vis spectra
of copper compounds. The thermal analyses of 1-6 reveal existence of a dihydrate form of each of them, which is
impossible to obtain in direct synthesis in aqueous media. The compounds 1-6 can be converted to metal oxide
micro and nanoparticles with usage of single precursor method, and the topology and size of formed particles is
governed by structure of precursors, structure of products and thermal conversion parameters.
Appendix A. Supplementary data
CCDC 1542008, 1542009, 1542010, 1425088, 1425087 and 1425089 contain the supplementary
crystallographic
data
for
1-6.
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.
Acknowledgments
This work part was financed by funds allocated by the Ministry of Science and Higher Education to the Institute
of General and Ecological Chemistry, Lodz University of Technology.
Figure 1. The solid state structures of compound 2 (a) and compound 5 (b), with atom numbering scheme,
plotted with 50% probability of displacement ellipsoids of non-hydrogen atoms. The disordered butyrate of
compound 2 ion is indicated by dashed lines. Hydrogen atoms were omitted for clarity. The symmetry generated
atoms of compound 5, indicated by dashed lines and A letter, were generated via -x, y, -z+0.5 symmetry
transformations.
Figure 2. The part of molecular packing, representing the layered structure of crystal nets of studied compounds.
Hydrogen atoms were omitted for clarity.
Figure 3. The multiple cyclic motifs of hydrogen bonds in the “aqueous layers” of butyrate (a) and isobutyrate
(b) compounds (aliphatic ends of carboxylate ions were omitted for clarity), and graphic representation of
formed six petals flower-like motifs. Letters a, b and c, added to the same number of the cyclic motif, indicate
the same graph, but formed by different molecules.
Figure 4. The SEM micrographs of CoO and NiO particles produced from compounds 1, 2, 4 and 5 in two
experiments (E1 and E2).
Figure 5. The SEM micrographs of CuO particles produced from compounds 3 and 6 in two experiments (E1 and
E2).
9

Table 1. Crystal data and structure refinement details for the studied compounds.
Compound
Empirical formula
Formula weight
1
C44H60CoN6O15
971.91
2
3
C44H58.35N6NiO14.18
956.91
C44H60CuN6O15
976.52
Crystal system, space group
Temperature [K]
Triclinic, P-1 (No. 2)
100(2)
Triclinic, P-1 (No. 2)
100(2)
Triclinic, P-1 (No. 2)
100(2)
Unit cell dimensions [Å, °]
a = 11.9803(6)
b = 13.2913(7)
c = 16.7880(8)
α = 73.873(3)
β = 79.264(3)
γ = 64.185(4)
a = 12.0102(2)
b = 13.1672(3)
c = 16.7724(3)
α = 74.1140(10)
β = 78.9010(10)
γ = 63.7960(10)
2281.02(8)
a = 12.0128(12)
b = 13.2449(15)
c = 16.7821(17)
α = 74.484(10)
β = 78.848(8)
γ = 63.987(9)
2303.3(5)
Volume [Å3]
2305.1(2)
Z, Calculated density [Mg/m3]
Absorption coefficient [mm-1]
F(000)
2, 1.400
2, 1.393
2, 1.408
3.557
1.237
1.308
1026
1012
1030
Crystal size [mm]
0.095 x 0.080 x 0.075
2.75 to 67.00
0.121 x 0.106 x 0.092
3.83 to 67.00
0.121 x 0.108 x 0.095
3.80 to 67.00
θ Range for data collection [°]
Index ranges
-13≤h≤11, -15≤k≤15, -19≤l≤20
23711 / 7903 [R(int) = 0.0445]
96.2
-14≤h≤14, -15≤k≤13, -20≤l≤20 -14≤h≤12, -15≤k≤15, -20≤l≤20
Reflections collected / unique
Completeness to θ = 25° [%]
Min. and max. transmission
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
R indices (all data)
24351 / 7839 [R(int) = 0.0171]
96.4
24264 / 7899 [R(int) = 0.0200]
96.2
0.740 and 0.778
7903 / 0 / 598
1.038
0.848 and 0.899
7839 / 0 / 653
0.845 and 0.880
7899 / 0 / 598
1.036
1.993
R1 = 0.0831, wR2 = 0.2267
R1 = 0.0845, wR2 = 0.2281
1.656 and -0.903
R1 = 0.0694, wR2 = 0.1889
R1 = 0.0713, wR2 = 0.1904
2.430 and -0.723
R1 = 0.1057, wR2 = 0.3716
R1 = 0.1062, wR2 = 0.3749
2.524 and -1.298
Largest diff. peak and hole [e•Å-3]
Compound
Empirical formula
Formula weight
4
C44H66CoN6O18
1025.95
5
C44H66N6NiO18
1025.73
6
C44H66CuN6O18
1030.56
Crystal system, space group
Temperature [K]
Monoclinic, C2/c (No. 15)
100(2)
Monoclinic, C2/c (No. 15)
100(2)
Monoclinic, C2/c (No. 15)
100(2)
Unit cell dimensions [Å, °]
a = 22.8520(16)
b = 11.8704(9)
c = 19.9921(14)
α = 90.00
a = 22.8571(18)
b = 11.8704(10)
c = 20.0150(16)
α = 90.00
a = 22.800(3)
b = 11.8973(18)
c = 19.967(2)
α = 90.00
β = 113.545(4)
γ = 90.00
β = 113.421(4)
γ = 90.00
β = 113.064(9)
γ = 90.00
Volume [Å3]
4971.6(6)
4983.1(7)
4983.3(11)
Z, Calculated density [Mg/m3]
Absorption coefficient [mm-1]
F(000)
4, 1.371
4, 1.367
4, 1.374
3.372
1.226
1.283
2172
2176
2180
Crystal size [mm]
0.099 x 0.095 x 0.091
4.22 to 72.38
0.105 x 0.093 x 0.090
4.22 to 72.57
0.100 x 0.097 x 0.090
4.22 to 72.41
θ Range for data collection [°]
Index ranges
-28≤h≤27, -14≤k≤14, -24≤l≤24
28083 / 4917 [R(int) = 0.0233]
100.0
-28≤h≤26, -14≤k≤14, -24≤l≤24 -28≤h≤27, -14≤k≤14, -24≤l≤24
Reflections collected / unique
Completeness to θ = 67° [%]
Min. and max. transmission
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [I>2σ(I)]
R indices (all data)
27776 / 4936 [R(int) = 0.0205]
100.0
26811 / 4915 [R(int) = 0.0202]
99.7
0.728 and 0.750
4917 / 0 / 314
1.110
0.971 and 0.905
0.868 and 0.906
4915 / 0 / 314
4936 / 0 / 315
1.046
1.041
R1 = 0.0641, wR2 = 0.1727
R1 = 0.0647, wR2 = 0.1733
1.513 and -1.221
R1 = 0.0666, wR2 = 0.1688
R1 = 0.0666, wR2 = 0.1688
1.816 and -1.105
R1 = 0.0681, wR2 = 0.1721
R1 = 0.0682, wR2 = 0.1723
1.683 and -1.280
Largest diff. peak and hole [e•Å-3]
10

Table 2. Selected structural data of the studied compounds.
Compound
1
2
3
4
5
6
M=Co1
M=Ni1
N4=N1i, N5=N2i, N6=N3i
M=Cu1
M=Co1
M=Ni1
M=Cu1
Symbols
bond length/Å [bond valence/valence units]
M—N1
M—N2
M—N3
M—N4
M—N5
M—N6
2.133(4) [0.334]
2.125(4) [0.341]
2.113(3) [0.352]
2.126(4) [0.338]
2.116(3) [0.349]
2.152(3) [0.317]
2.086(3) [0.328]
2.139(4) [0.351]
2.076(3) [0.417]
2.145(4) [0.346]
2.136(3) [0.354]
2.076(3) [0.417]
2.211(3) [0.289]
angle/°
2.129(2) [0.337]
2.089(2) [0.326]
2.087(2) [0.328]
2.088(2) [0.327]
2.089(2) [0.326]
2.087(2) [0.328]
2.088(2) [0.327]
2.061(2) [0.434]
2.162(2) [0.330]
2.166(3) [0.327]
2.061(2) [0.434]
2.162(2) [0.330]
2.166(3) [0.327]
2.086(3) [0.328]
2.079(3) [0.335]
2.084(3) [0.330]
2.086(3) [0.328]
2.105(2) [0.312]
2.131(2) [0.336]
2.129(2) [0.337]
2.129(2) [0.337]
2.131(2) [0.336]
2.129(2) [0.337]
N1—M—N2
N1—M—N3
N1—M—N4
N1—M—N5
N1—M—N6
N2—M—N3
N2—M—N4
N2—M—N5
N2—M—N6
N3—M—N4
N3—M—N5
N3—M—N6
N4—M—N5
N4—M—N6
N5—M—N6
78.76(14)
94.08(13)
169.03(13)
92.87(13)
91.90(12)
96.72(13)
93.69(14)
165.60(13)
90.35(12)
78.78(13)
95.54(13)
171.51(13)
96.09(13)
96.12(13)
78.13(12)
79.92(11)
93.62(10)
170.25(10)
92.54(10)
91.58(10)
96.08(10)
93.13(11)
167.82(10)
90.72(10)
80.24(10)
93.92(10)
172.07(11)
95.41(1)
78.77(13)
78.37(8)
92.77(8)
172.16(12)
95.94(8)
93.31(8)
97.22(9)
95.94(8)
88.34(12)
170.47(8)
93.31(8)
170.47(8)
78.37(12)
78.37(8)
92.77(8)
97.22(9)
79.91(8)
92.73(8)
172.68(12)
94.82(8)
92.89(8)
96.04(8)
94.82(8)
89.01(12)
171.56(8)
92.88(8)
171.55(8)
79.79(12)
79.91(8)
92.73(8)
96.04(8)
79.14(9)
93.12(9)
171.43(13)
94.70(9)
93.56(9)
97.15(9)
94.70(9)
89.09(12)
170.79(9)
93.56(9)
170.79(9)
77.50(14)
79.14(9)
93.12(9)
97.15(9)
93.43(11)
168.99(12)
92.53(12)
92.66(11)
97.09(11)
94.66(12)
164.77(12)
89.57(11)
78.50(12)
95.88(11)
171.73(11)
95.72(11)
95.36(10)
79.86(9)
96.14(12)
78.27(11)
Symmetry transformations used to generate equivalent atoms: (i) -x, y, -z+0.5.
11

Table 3. Hydrogen bonds in the studied compounds [Å, °].
D-H•••A
d(D-H)
2
d(H•••A)
2
d(D•••A)
<(DHA)
Compound
1
3
1
3
1
2
3
1
2
3
O89—H89O•••O95
O89—H89P•••O51
O90—H90O•••O51
O90—H91P•••O91
O91—H91O•••O42i
O91—H91P•••O52
O92—H92O•••O89
O92—H92P•••O94
O93—H93O•••O98
O93—H93O•••O42’
O93—H93P•••O92
O94—H94O•••O93ii
O94—H94P•••O99
O95—H95O•••O96
O95—H95O•••O41’
O95—H95P•••O52i
O96—H96O•••O42
O96—H96P•••O98
O97—H97O•••O99
O97—H97P•••O51
O98—H98O•••O41
O98—H98P•••O41iii
O99—H99O•••O42iv
O99—H99P•••O90
Compound
0.88
0.89
0.89
0.91
0.91
0.90
0.90
0.91
0.84
0.88
0.89
0.89
0.91
0.91
0.89
0.90
0.90
0.83
0.83
0.88
0.90
0.90
0.87
0.87
0.90
0.87
0.89
0.91
0.89
0.88
0.86
0.89
0.86
5
0.88
0.89
0.89
0.91
0.91
0.90
0.90
0.91
0.83
1.85
1.92
1.93
2.13
1.99
1.82
1.82
1.87
1.91
1.90
1.93
2.03
2.24
1.92
1.81
1.83
1.89
1.83
2.32
1.91
1.95
2.04
1.61
2.36
1.94
1.85
2.01
1.96
1.93
1.78
1.94
1.83
1.99
5
1.87
1.96
1.97
2.18
2.05
1.78
1.82
1.85
1.86
2.735(6) 2.776(5) 2.749(7) 179.7 176.3 179.2
2.812(6) 2.813(5) 2.858(7) 179.6 179.0 179.8
2.807(6) 2.907(5) 2.845(7) 167.9 168.1 166.7
3.012(5) 3.112(4) 3.060(7) 164.0 161.6 161.5
2.902(6) 2.825(6) 2.954(8) 179.6 173.4 175.2
2.723(5) 2.703(5) 2.681(7) 179.6 177.0 179.0
2.722(5) 2.729(4) 2.721(5) 179.7 176.4 179.6
2.780(6) 2.797(5) 2.754(5) 179.8 178.3 178.9
2.743(6) 2.659(6) 2.690(7) 175.4 174.1 172.7
3.100(9)
156.1
0.88
0.90
0.91
0.90
0.89
0.90
0.91
0.90
1.91
1.93
2.05
1.77
1.89
1.99
2.03
1.76
2.786(5) 2.788(4) 2.773(5) 177.1 174.7 175.0
2.834(6) 2.843(5) 2.885(6) 176.4 175.8 178.5
2.957(6) 2.942(4) 2.938(6) 176.9 178.7 178.1
2.674(7) 2.483(7) 2.662(7) 179.6 178.0 177.0
3.156(10)
151.8
0.91
0.88
0.90
0.91
0.89
0.89
0.86
0.89
0.87
4
0.90
0.88
0.88
0.87
0.89
0.88
0.86
0.89
0.86
6
1.94
1.79
2.02
1.92
1.92
1.74
1.95
1.88
1.98
4
1.93
1.81
2.05
1.93
1.95
1.70
1.94
1.85
2.03
6
2.847(7) 2.841(6) 2.833(7) 179.7 172.9 178.2
2.661(8) 2.716(8) 2.690(9) 176.9 177.3 175.7
2.845(6) 2.843(6) 2.845(6) 152.2 154.2 150.5
2.824(6) 2.858(5) 2.792(7) 170.5 171.6 170.3
2.804(6) 2.804(5) 2.826(7) 168.1 170.5 168.1
2.629(7) 2.654(18) 2.586(8) 178.3 178.7 179.0
2.773(6) 2.767(15) 2.773(6) 159.3 162.5 162.9
2.765(6) 2.718(6) 2.739(7) 179.5 171.3 177.6
2.841(5) 2.849(4) 2.884(6) 171.2 171.5 171.0
4
5
6
4
5
6
O91—H91O•••O21
O91—H91P•••O92
O92—H92O•••O93v
O92—H92P•••O22v
O93—H93O•••O21
O93—H93P•••O96
O94—H94O•••O22vi
O94—H94P•••O93
O95—H95O•••O91
O95—H95P•••O97
O96—H96O•••O95
O96—H96P•••O94vii
O97—H97O•••O22viii
O97—H97P•••O95ix
0.84
0.87
0.79
0.93
0.84
0.85
0.82
0.91
0.82
0.81
0.81
0.86
0.91
0.80
0.84
0.87
0.80
0.93
0.84
0.85
0.82
0.91
0.82
0.81
0.81
0.86
0.91
0.80
0.84
0.87
0.79
0.94
0.85
0.85
0.82
0.92
0.82
0.80
0.81
0.85
0.91
0.80
1.94
1.89
2.20
1.83
1.88
1.92
2.04
1.82
1.83
1.80
2.00
1.88
1.91
1.99
1.93
1.89
2.18
1.83
1.88
1.92
2.04
1.82
1.87
1.84
2.03
1.89
1.93
2.06
1.95
1.88
2.19
1.83
1.88
1.92
2.05
1.82
1.83
1.80
2.00
1.89
1.91
1.99
2.771(4) 2.766(3) 2.779(3) 172.6 172.0 172.4
2.751(3) 2.749(3) 2.747(3) 171.4 169.5 171.6
2.927(3) 2.916(3) 2.918(3) 153.4 153.2 153.3
2.763(3) 2.764(3) 2.767(3) 174.5 174.4 174.6
2.716(3) 2.719(3) 2.719(3) 173.6 173.9 173.8
2.754(4) 2.750(3) 2.754(4) 164.3 163.4 164.5
2.856(4) 2.855(3) 2.858(3) 170.2 170.2 170.6
2.722(4) 2.725(3) 2.726(4) 170.6 172.0 169.5
2.571(5) 2.601(4) 2.573(5) 149.3 148.2 149.5
2.569(5) 2.621(4) 2.568(5) 159.6 162.1 159.8
2.690(5) 2.720(4) 2.695(5) 143.0 142.7 143.2
2.731(4) 2.744(3) 2.734(4) 173.2 173.0 172.4
2.719(4) 2.724(3) 2.722(4) 147.8 144.8 147.6
2.620(7) 2.708(5) 2.625(7) 134.6 137.4 135.1
Symmetry transformations used to generate equivalent atoms: (i) –x+1, -y+1, -z+1; (ii) –x+1, -y+1, -z; (iii) –x+1, -y+2, -z; (iv) x, y-1, z; (v)
–x+0.5, y+0.5, -z+0.5; (vi) –x+0.5, y-0.5, -z+0.5; (vii) –x+0.5, -y+1.5, -z+1; (viii) x, -y+2, z+0.5; (ix) –x+0.5, -y+2.5, –z+1.
12

Table 4. Stacking and C-H•••π interactions in the studied compounds [Å, °]. Each ring is indicated by one atom, which belongs solely to this
ring. The  is a dihedral angle between planes I and J,  is an angle between Cg(I)-Cg(J) vector and normal to plane I, dp is a perpendicular
distance of Cg(I) on ring J plane.
R(I)•••R(J)
d(Cg•••Cg)
2
dp
2

2
1
5
0

Compound
R(N6)•••R(C30)i
1
3
1
1
4
0
3
1
6
0
1
2
3
1
3
3.7641(2)
4
3.7862(1)
5
3.7505(4)
6
22.8 23.7 23.2
3.4512
4
3.4450
5
3.4462
6
Compound
R(C6)•••R(C6)ii
4
5
6
3.7419(3)
3.8094(3)
d(H•••Cg)
2
3.7637(6)
27.0 28.0 27.0
d(C•••Cg)
3.3355
3.3643
<(CHCg)
2
3.3543
C-H•••R(J)
Compound
1
3
1
2
3
1
3
C31—H31•••R(N1)i
C36—H36•••R(N2)
C42—H42B•••R(C18)iii
C43—H43B•••R(C30)i
C44—H44A•••R(N4)iii
C53—H53A•••R(N1)iv
C53—H53B•••R(C6)iv
C54—H54A•••R(C18)v
Compound
2.54
2.98
3.06
3.24
3.08
3.00
2.82
2.88
4
2.56
2.56
3.04
2.86
2.99
2.88
3.02
2.89
3.03
6
3.4887(2)
3.7577(2)
3.5908(2)
4.2329(2)
3.6046(2)
3.7713(2)
3.5052(2)
3.7960(2)
4
3.5117(1)
3.7414(1)
3.4092(1)
3.8301(1)
3.5341(1)
3.8131(1)
3.5133(1)
3.7828(1)
5
3.5087(4)
3.7853(4)
3.4196(4)
3.7955(4)
3.5678(4)
3.8256(4)
3.5353(4)
3.8189(4)
6
176.5
140.1
115.2
172.7
115.2
136.0
126.7
156.4
4
177.2
139.6
118.8
136.8
108.3
136.0
125.2
159.2
5
176.2
136.3
116.5
138.9
127.9
138.3
123.6
138.2
6
2.97
2.82
3.04
3.09
3.04
2.85
2.85
5
C22—H22•••R(C18)
2.67
2.69
2.65
3.6608(3)
3.6823(3)
3.6455(6)
171.3
169.5
171.2
Symmetry transformations used to generate equivalent atoms: (i) –x, -y+2, -z; (ii) -x, -y+1, -z+1; (iii) x, y+1, z; (iv) –x+1, -y+1, -z+1; (v)
x+1, y, z.
13

Table 5. Vibrational frequencies and their assignments for the studied compounds.
phen
[23, 24,
53, 69]
Compound
Co(butyr)2 Ni(butyr)2 Cu(butyr)2
Assignment
1
2
3
3400 br
3220 br
3057 w
2958 m
2928 w
2870 w
1650 w
1627 w
1552 s
3400 br
3220 br
3057 w
2958 m
2928 w
2870 w
1650 w
1627 w
1552 s
3400 br
3220 br
3057 w
2958 w
2928 w
2870 w
1650 w
1620 w
1563 s
1514 s
1495 w
1455 w
1425 s
1407 s
ν OH (H2O)
ν OH (H2O)
ν CH (ar)
νas CH (CH3)
νas CH (CH2)
3058
2963 m
2938 w
2877 w
2963 m
2935 w
2975 w
2963 m
2932 w
2874 w
νs CH (CH3, CH2)
δ OH (H2O)
ν CC (ar), ν CN (ar)
νas COO
ν CC (ar), ν CN (ar)
ρ CH (ar)
1617
1556 s
1557 s
1588 s
1516 s
1516 s
1506
1492
1496 w
1462 w
1425 s
1496 w
1462 w
1425 s
1461 w
1420 s
1460 w
1419 s
1463 w
1428 s
δas CH (CH3)
νs COO
ν CC (ar), ν CN (ar), δ CH (ar)
δs CH (CH3), ν CC (ar),
ν CN (ar), δ CH (ar)
τ CH (CH2)
1408 m
1408 m
1405
1345
1349 m
1349 m
1347 m
1335 m
1340 m
1347 m
1307 m
1257 m
1224 m
1147 m
1104 m
1039 w
1005 w
970 w
868 w
848 s
1307 m
1257 m
1224 m
1147 m
1104 m
1039 w
1005 w
970 w
868 w
848 s
1307 m
1256 m
1222 m
1144 m
1100 m
1050 w
1005 w
1315 m
1246 m
1212 w
1312 m
1260 m
1213 w
1317 m
1265 m
1213 w
ω CH (CH2)
ω CH (CH2), τ CH (ar)
δ CH (ar)
ν CCC (Pr), δ CH (ar)
ν CCC (Pr)
1218
1142
1092
1101 w
1048 w
1010 w
930 m
1100 m
1105 m
ν CCC (Pr)
ν CCC (Pr)
890 w
851 s
776 m
726 s
644 w
426 w
894 m
877 w
872 w
882
855
786
737
ν CCC (Pr), τ CH (ar)
τ CH (ar)
ω COO, ω CH (ar)
ρ CH (CH2), ω CH (ar)
σ COO
775 w
725 s
642 w
425 w
775 w
725 s
642 w
425 w
800 w
718 m
644 w
403 w
794 w
727 w
667 w
405 w
800 w
730 w
655 m
427 m
ν M–N
phen
[23, 24,
53, 69]
Compound
Co(ibutyr)2 Ni(ibutyr)2 Cu(ibutyr)2
Assignment
4
5
6
3400 br
3210 br
3054 w
2969 m
2915 w
2875 w
1654 w
1625 m
1551 s
1518 s
1495 w
1472 m
1425 s
1409 m
1366 m
1346 w
1307 m
1284 m
1224 m
1206 w
1196 w
1169 w
1148 m
1104 m
1088 m
970 w
3400 br
3210 br
3054 w
2969 m
2915 w
2875 w
1654 w
1625 m
1551 s
1518 s
1495 m
1472 m
1425 s
1409 m
1366 m
1346 w
1307 m
1284 m
1224 m
1206 w
1196 w
1169 w
1148 m
1104 m
1088 m
970 w
3400 br
3210 br
3054 w
2963 m
2918 w
2867 w
ν OH (H2O)
ν OH (H2O)
ν CH (ar)
νas CH (CH3)
ν CH (>CH-)
νs CH (CH3)
3058
2969 m
2934 w
2871 w
2696 m
2935 w
2871 w
2966 m
2933 w
2871 w
δ OH (H2O)
ν CC (ar), ν CN (ar)
νas COO
ν CC (ar), ν CN (ar)
ρ CH (ar)
1621 w
1560 s
1516 s
1495 w
1469 m
1425 s
1408 w
1366 m
1617
1559 s
1568 s
1587 s
1506
1492
1472 m
1418 s
1472 m
1420 s
1474 m
1421 s
δas CH (CH3)
νs COO
ν CC (ar), ν CN (ar), δ CH (ar)
δs CH (CH3)
ν CC (ar), ν CN (ar), δ CH (ar)
δ CH (>CH-)
δ CH (>CH-)
τ CH (ar)
1405
1345
1360 w
1360 w
1290 m
1363 m
1309 w
1273 m
1224 m
1210 w
1308 m
1286 m
1315 m
1284 m
1218
1204
1187
τ CH (ar)
τ CH (ar)
δ CCC (iPr)
δ CH (ar)
1167 w
1142 m
1105 m
1090 m
960 w
1169 w
1099 s
1169 w
1099 s
1169 w
1097 s
1142
1092
δ CCC (iPr), δ CH (>CH-)
δ CH (ar)
964 w
929 m
δ CH (>CH-)
δ CH (>CH-)
τ CH (ar)
923 m
868 w
847 s
775 w
923 m
868 w
847 s
775 w
923 m
930 m
923 w
882
855
786
737
854 s
783 m
727 s
845 m
762 w
849 m
779 w
849 w
784 w
νs CCC (iPr), τ CH (ar)
ω COO, ω CH (ar)
ω CH (ar)
727 s
727 s
642 m
531 w
422 m
642 m
531 w
422 m
647 w
531 w
425 m
658 m
560 w
440 w
670 m
572 w
442 w
670 s
565 w
439 w
σ COO
δ CC (>CH-COO)
ν M–N
Vibrations symbols: w – weak, m – medium, s – strong, br – broadened, ν – stretching, δ – bending, ρ – rocking, σ – scissoring, τ – twisting,
ω – wagging, s – symmetric, as – asymmetric, ar – aromatic ring, Pr – propyl group, iPr – isopropyl group.
14

Table 6. Absorption maxima (nm) and their assignment for the studied compounds.
Compound
Compound
Compound
Assignment
Assignment
Assignment
1
4
2
5
3
6
218
254
294
325
350
446
540
221
261
295
325
348
442
534
π → π* (phen)
π → π* (phen)
n → π* (phen)
n → π* (phen)
n → π* (phen)
LMCT
218
254
294
326
340
410
520
785
220
260
295
327
341
411
534
784
π → π* (phen)
π → π* (phen)
n → π* (phen)
n → π* (phen)
n → π* (phen)
LMCT
218
254
294
330
348
218
256
294
326
346
π → π* (phen)
π → π* (phen)
n → π* (phen)
n → π* (phen)
n → π* (phen)
2B1g→ 2Eg , 2B1g→
682
678
2B2g , 2B1g→ 2A1g
4T1g(F) → 4T1g(P)
3A2g→ 3T1g(P)
3A2g→ 3T1g(F)
Table 7. Temperature ranges, mass losses / residual mass (experimental/theoretical) and removal species / final products of thermal
decomposition steps of the studied compounds.
Compound
1
2
3
4
5
6
40 °C – 185 °C
16.14% / 16.68%
- 9 H2O
40 °C – 185 °C
16.56% / 15.40%
- 8.18 H2O
a)
185 °C – 360 °C
14.42% / -
40 °C – 175 °C
16.67% / 16.60%
- 9 H2O
30 °C – 175 °C
21.04% / 21.07%
- 12 H2O
30 °C – 130 °C
21.11% / 21.07%
- 12 H2O
40 °C – 170 °C
21.19% / 20.98%
- 12 H2O
a)
a)
185 °C – 360 °C
19.79% / 19.98%
- 2 H2O, -2 butyr,
+ 0.5 O2
175 °C – 370 °C
19.13% / 18.95%
- 2 H2O, -2 ibutyr ,
+ 0.5 O2
170 °C – 340 °C
19.97% / 18.85%
- 2 H2O, -2 ibutyr ,
+ 0.5 O2
175 °C – 400 °C
26.52% / -
b)
400 °C – 520 °C
50.77% / -
Totally
76.29% / 75.25%
- 2 H2O, -2 butyr,
-3 phen, + 0.5 O2
520 °C
175 °C – 360 °C
16.38% / -
b)
360 °C – 490 °C
55.76% / -
Totally
72.14% / 71.64%
- 2 H2O, -2 ibutyr,
-3 phen, + 0.5 O2
490 °C
b)
360 °C – 500 °C
60.77% / -
Totally
75.19% / 76.79%
- 2 H2O, -2 butyr,
-3 phen, + 0.5 O2
500 °C
370 °C – 500 °C
55.25% / 55.63%
- 3 phen
370 °C – 490 °C
52.17% / 52.69%
- 3 phen
340 °C – 550 °C
50.78% / 52.46%
- 3 phen
500 °C
490 °C
550 °C
8.82% / 7.71%
CoO
8.25% / 7.81%
NiO
7.04% / 8.15%
CuO
7.66% / 7.29%
CoO
6.75% / 7.29%
NiO
8.06% / 7.71%
CuO
References
[1] A. Trzesowska-Kruszynska, J. Mol. Struct. 1072 (2014) 284.
[2] R. Kruszynski, T. Sieranski, M. Swiatkowski, M. Zielak, J. Wojciechowski, M. Dzierzawska, E. Czubacka, J. Chem. Crystallogr. 45
(2015) 484.
[3] J. Mitra, K. Pal, S. Sarkar, Dalton Trans. 42 (2013) 13905.
[4] A. Trzesowska-Kruszynska, J. Coord. Chem. 64 (2011) 663-678.
[5] L. Radovanovic, J. Rogan, D. Poleti, M. Milutinovic, M. Rodic, Polyhedron 112 (2016) 18.
[6] J. D. Einkauf, B. C. Chan, D. T. de Lill, Polyhedron 128 (2017) 149.
[7] B. Nowicka, W. Nitek, P. Pietrzyk, B. Sieklucka, Polyhedron 119 (2016) 1.
[8] A. Trzesowska-Kruszynska, J. Coord. Chem. 67 (2014) 120-135.
[9] D. Czakis-Sulikowska, J. Kaluzna, J. Therm. Anal. 47 (1996) 1763.
[10] D. Czakis-Sulikowska, J. Kaluzna, J. Radwanska-Doczekalska, J. Therm. Anal. Calorim. 54 (1998) 103.
[11] D. Czakis-Sulikowska, J. Kaluzna, J. Therm. Anal. Calorim. 58 (1999) 51.
[12] D. Czakis-Sulikowska, J. Kaluzna-Czaplinska, J. Therm. Anal. Calorim. 62 (2000) 821.
[13] G.E. Jackson, A.N. Hammouda, F.M. Elmagbari, R.P. Bonomo, Polyhedron 123 (2017) 23.
[14] R.A. Agarwal, N.K. Gupta, Coord. Chem. Rev. 332 (2017) 100.
[15] M. Azam, S.I. Al-Resayes, A. Trzesowska-Kruszynska, R. Kruszynski, P. Kumar, S.L. Jain, Polyhedron 124 (2017) 177.
[16] J.G. Małecki, R. Kruszynski, Z. Mazurak, Polyhedron 28 (2009) 3891.
[17] R. Kruszynski, A. Malinowska, D. Czakis-Sulikowska, A. Lamparska, J. Coord. Chem. 62 (2009) 911.
[18] J.G. Małecki, M. Jaworska, R. Kruszynski, J. Organomet. Chem. 693 (2007) 2903.
[19] J.H.N. Buttery, Effendy, S. Mutrofin, N.C. Plackett, B.W. Skelton, N. Somers, C.R. Whitaker, A.H. White, Z. Anorg. Allg. Chem. 632
(2006) 1839.
[20] C.R. Groom, I.J. Bruno, M.P. Lightfoot, S.C. Ward, Acta Crystallogr. B 72 (2016) 171.
[21] B.W. Skelton, A.F. Waters, A.H. White, Aust. J. Chem. 49 (1996) 99.
[22] D.W. Margerum, C.V. Banks, Anal. Chem. 26 (1954) 200.
[23] T. Sieranski, R. Kruszyński, J. Therm. Anal. Calorim. 109 (2012) 141.
[24] R. Kruszynski, Inorg. Chim. Acta 371 (2011) 111.
[25] P. Szymanski, T. Fraczek, M. Markowicz, E. Mikiciuk-Olasik, Biometals 25 (2012) 1089.
[26] M. Barcelo-Olivier, A. Garcia-Raso, A. Terron, E. Molins, M.J. Prieto, V. Moreno, J. Martinez, V. Llado, I. Lopez, A. Gutierrez, P.V.
Escriba, J. Inorg. Biochem. 101 (2007) 649.
[27] H. Mansouri-Torshizi, M. Saeidifar, Z.Y. Ghasemi, M. Khastan, A. Divsalar, A.A. Saboury, J. Korean Chem. Soc., 55 (2011) 70.
[28] Y. Geldmacher, I. Kitanovic, H. Alborzina, K. Bergerhoff, R. Rubbiani, P. Wefelmeier, A. Prokop, R. Gust, I. Ott, S. Wolfl, W.S.
Sheldrick, ChemMedChem 6 (2011) 429.
15

[29] S. Chandraleka, K. Ramya, G. Chandramohan, D. Dhanasekaran, A. Priyadharshini, A. Panneerselvam, J. Saudi Chem. Soc. 18 (2014)
953.
[30] A. Aliakbari, E. Najafi, M.M. Amini, S.W. Ng, Monatsh. Cehm. 145 (2014) 1277.
[31] A. Barakat, M. Al-Noaimi, M. Suleiman, A.S. Aldwayyan, B. Hammouti, T.B. Hadda, S.F. Haddad, A. Boshaala, I. Warad, Int. J.
Mol. Sci. 14 (2013) 23941.
[32] N. Srinivasan, S. Thirumaran, S. Ciattini, J. Mol. Struct. 1026 (2012) 102.
[33] F.J. Welcher, Analityczne zastosowanie kwasu wersenowego (eng. The Analytical Uses of Etylenediamineteraacetic Acid), WNT,
Warsaw, Poland, 1963.
[34] X-RED. Version 1.18. STOE & Cie GmbH, Darmstadt, Germany, 1999.
[35] G.M. Sheldrick, Acta Crystallogr. A 71 (2015) 3.
[36] G.M. Sheldrick, Acta Crystallogr. C 71 (2015) 3.
[37] G.M. Sheldrick, Acta Crystallogr. A 64 (2008) 112.
[38] Powder Diffraction File International Center of Diffraction Data, 12 Campus Boulevard, Newton Square, PA, USA, 2003.
[39] W. Mizerski, Tablice chemiczne (eng. Chemical Tables), Wydawnictwo Adamantan, Warsaw, Poland, 2004.
[40] D.L. Kepert, in: S.J. Lippard (Ed.), Progress in Inorganic Chemistry, John Wiley & Sons, Inc., Hoboken, NJ, USA, 1997, pp. 1-65.
[41] W.H. Zachariasen, J. Less-Common Met. 62 (1978) 1.
[42] I.D. Brown, Acta Crystallogr. B 53 (1997) 381.
[43] I.D. Brown, Acta Crystallogr. B 48 (1992) 553.
[44] M. O'Keeffe, N.E. Brese, Acta Crystallogr. B 47 (1997) 192.
[45] A. Trzesowska, R. Kruszynski, T.J. Bartczak, Acta Crystallogr. B 60 (2004) 174.
[46] A. Trzesowska, R. Kruszynski, T.J. Bartczak, Acta Crystallogr. B 61 (2005) 429.
[47] A. Trzesowska, R. Kruszynski, T.J. Bartczak, Acta Crystallogr. B 62 (2006) 745.
[48] G.J. Palenik, Inorg. Chem. 42 (2003) 2725.
[49] T.A. Mirnaya, A.P. Polishchuk, A.S. Tolochko, S.V. Volkov, Kristallografiya, 38 (1993) 49.
[50] N. Aurangzeb, C.E. Hulme, C.A. McAuliffe, R.G. Pritchard, M. Watkinson, M.R. Bermejo, A. Sousa, Chem. Commun. (1994) 2193.
[51] C. Schaffer, H. Bogge, A. Merca, I.A. Weinstock, D. Rehder, E.T.K. Haupt, A. Muller, Angew. Chem. Int. Edit. 48 (2009) 8051.
[52] L. Infantes, J. Chisholm, S. Motherwell, CrystEngComm 5 (2003) 480.
[53] M. Swiatkowski, R. Kruszynski, J. Coord. Chem. 70 (2017) 642.
[54] E.G. Il’na, S.I. Troyanov, K.M. Dunaeva, Russ. J. Coord. Chem. 18 (1992) 882.
[55] G.B. Deacon, R.J. Phillips, Coord. Chem. Rev. 33 (1980) 227.
[56] K. Nakamoto, Infrared and Raman Spectra of Inorganic and Coordination Compounds, John Wiley and Sons, New York, USA, 1997.
[57] Y. Deng, Y. Bai, L.-G. Zhu, J.-X. Jiang, G.-Q. Lai, J. Coord. Chem. 65 (2012) 2793.
[58] A. Prisecaru, V. McKee, O. Howe, G. Rochford, M. McCann, J. Colleran, M. Pour, N. Barron, N. Gathergood, A. Kellett, J. Med.
Chem. 56 (2013) 8599.
[59] A.B.P. Lever, Inorganic Electronic Spectroscopy, second ed., Elsevier, Amsterdam, 1984.
[60] J. Rogan, D. Poleti, L. Karanovic, G. Bogdanovic, A. Spasojevic-de Bire, D.M. Petrovic, Polyhedron 19 (2000) 1415.
[61] E. Vinuelas-Zahinos, M.A. Maldonado-Rogado, F. Luna-Giles, F.J. Barros-Garcia, Polyhedron 27 (2008) 879.
[62] L.S. Skorokhod, I.I. Seifullina, V.V. Minin, V.G. Vlasenko, I.V. Pirog, Russ. J. Inorg. Chem. 52 (2007) 1006.
[63] B.K. Das, S.J. Bora, M. Chakrabortty, L. Kalita, R. Chakrabarty, R. Barman, J. Chem. Sci. 118 (2006) 487.
[64] G.G. Mohamed, Spectrochim. Acta A 62 (2005) 1165.
[65] G.Y. Nagesh, K.M. Raj, B.H.M. Mruthyunjayaswamy, J. Mol. Struct. 1079 (2015) 423.
[66] R.P. Sharma, S. Kumar, A. Saini, P. Venugopalan, A. Rodriguez-Dieguez, J.M. Salas, J. Mol. Struct. 1071 (2014) 11.
[67] J.M. Seco, M.J. Gonzalez Garmendia, M. Quiros, J. Coord. Chem. 55 (2002) 345.
[68] S. Kumar, R.P. Sharma, P. Venugopalan, J. Jezierska, A. Wojciechowska, V. Ferretti, Inorg. Chim. Acta 432 (2015) 221.
[69] M.J. Muniz-Miranda, J. Phys. Chem. A 104 (2000) 7803.
16

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Synopsis
The two series of new isostructural coordination compounds containing cobalt, nickel, copper butyrates or
isobutyrates and 1,10-phenanthroline were synthesized, structurally characterized, and their spectroscopic and
thermal properties were investigated. The studied compounds exhibit layered packing in crystal net. The
carboxylate anions function as linkers between these layers and allow pinning them together via hydrogen bonds
and C—H•••π intermolecular interactions. Due to placement of carboxylate anions out of coordination moieties,
the presented compounds can be ideal standards in spectroscopic determinations of coordination type of but and
ibut ions in coordination compounds.