Copper(II) complexes with Schiff bases: Structures and thermal behavior

Article abstract of DOI:10.1134/S0022476614060092

Ligands with Schiff bases are obtained in the condensation of propylenediamine (pda) or 2,2-dimethylpropylenediamine (dmpda) with acetylacetone (Hacac) in the 1:2 molar ratio. The ligands are characterized by the elemental analysis methods, T _melt = 90-92 °C for pda(Hacac)₂ (pda(acac)₂ is N,N′-propylene-bis(acetylacetoniminato) (2-)), T _melt = 84-86 °C for dmpda(Hacac)₂ (dmpda(acac)₂ is N,N′-2,2-dimethylpropylene-bis(acetylacetoniminato) (2-)). The tautomerism of the ligands is established by the single crystal X-ray diffraction (XRD) analysis, IR spectroscopy, and ¹H, ¹³C NMR spectrometry. The synthesized complexes [Cu(pda(acac)₂)] (1), T _melt = 121-122 °C and [Cu(dmpda(acac)₂)] (2), T _melt = 156-158 °C are studied by the XRD method. In both complexes, copper atoms have a planar square geometry, and the chelate bond lengths and angles are: Cu-O ≈ Cu-N 1.903(2)-1.942(3) ?, ∠O-Cu-N = 94.44(12)-94.99(12)° for 1 and Cu-O ≈ Cu-N 1.909(1)-1.943(2) ?, ∠O-Cu-N = 94.63(6)° for 2. By the thermogravimetric method it is found that both complexes can be passed practically quantitatively into the gas phase.

Full text of DOI:10.1134/S0022476614060092

Journal of Structural Chemistry. Vol. 55, No. 6, pp. 1067-1074, 2014.
Original Russian Text © 2014 S. I. Dorovskikh, N. V. Kuratieva, S. V. Tkachev, S. V. Trubin, P. A. Stabnikov, N. B. Morozova.
COPPER(II) COMPLEXES WITH SCHIFF BASES:
STRUCTURES AND THERMAL BEHAVIOR
S. I. Dorovskikh, N. V. Kuratieva, S. V. Tkachev,
S. V. Trubin, P. A. Stabnikov, and N. B. Morozova
UDC 541.49:546.562:539.12
Ligands with Schiff bases are obtained in the condensation of propylenediamine (pda) or 2,2-
dimethylpropylenediamine (dmpda) with acetylacetone (Hacac) in the 1:2 molar ratio. The ligands are
characterized by the elemental analysis methods, Tmelt = 90-92 °C for pda(Hacac)2 (pda(acac)2 is N,N′-
propylene-bis(acetylacetoniminato) (2-)), Tmelt = 84-86 °C for dmpda(Hacac)2 (dmpda(acac)2 is N,N′-2,2-
dimethylpropylene-bis(acetylacetoniminato) (2-)). The tautomerism of the ligands is established by the
1
13
single crystal X-ray diffraction (XRD) analysis, IR spectroscopy, and H, C NMR spectrometry. The
synthesized complexes [Cu(pda(acac)2)] (1), Tmelt = 121-122 °C and [Cu(dmpda(acac)2)] (2), Tmelt = 156-
158 °C are studied by the XRD method. In both complexes, copper atoms have a planar square geometry,
and the chelate bond lengths and angles are: Cu–O ≈ Cu–N 1.903(2)-1.942(3) Å, ∠O–Cu–N = 94.44(12)-
94.99(12)° for 1 and Cu–O ≈ Cu–N 1.909(1)-1.943(2) Å, ∠O–Cu–N = 94.63(6)° for 2. By the
thermogravimetric method it is found that both complexes can be passed practically quantitatively into the
gas phase.
DOI: 10.1134/S0022476614060092
Keywords: ligands with Schiff bases, copper(II) complexes, single crystal X-ray diffraction analysis,
thermogravimetry.
INTRODUCTION
Complexes of 3d transition metals with Schiff bases are being extensively studied with respect to their practical
application as catalysts [1-3] and oxygen carriers [4]. Some copper(II) chelates with Schiff bases exhibit luminescent
properties [5]. One-electron Cu(II)/Cu(I) reduction processes of [Cu(pda(acac)2)⋅H2O] and [Cu(pda(acac)2)⋅KClO4] [6]
complexes in acetonitrile solutions are investigated.
Copper(II) chelates with Schiff bases ([Cu(en(acac)2)] and [Cu(Meen(acac)2)]) were synthesized for the first time by
McCarthy et al. [4]. By the electronographic study of the gas phase the structure of a number of complexes is determined:
[Cu(en(acac)2)] [7, 8], [Cu(salen)] [8, 9] (en(acac)2 is N,N′-ethylene-bis(acetylacetoniminato) (2-), salen is N,N′-ethylene-
bis(salicylaldiminato) (2-)). It is shown that the molecules have an almost planar structure of the CuN2O2 coordination center.
In [10] it is reported that the [Cu(en(acac)2)] complex sublimates congruently in the temperature range of 450-600 K and can
be considered as a potential precursor for obtaining copper-containing films by metal organic chemical vapor deposition
Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia;
reter16@yandex.ru. Translated from Zhurnal Strukturnoi Khimii, Vol. 55, No. 6, pp. 1124-1131, November-December, 2014.
Original article submitted August 6, 2014.
0022-4766/14/5506-1067 © 2014 by Pleiades Publishing, Ltd.
1067

(MO СVD). The main problem hindering the wide application of copper(II) complexes with the mentioned ligands is their
moderate volatility.
Variation of functional groups in the ligands makes it possible to change the volatility of the respective copper(II)
complexes in wide ranges [11-13]. As a rule, the introduction of terminal CF3 groups results in an increase in the volatility of
transition metal complexes with β-diketones and their derivatives by a few orders of magnitude [11, 12]. However, in
a number of works it is shown that in the case of Ni and Сu chelates with Schiff bases the introduction of CF3 groups causes
a decrease in volatility [12, 13]. By the example of [Ni(en(acac)2)] and [Ni(Meen(acac)2)] complexes it is shown that the
variation of substituents in the ethylenediimine moiety leads to a four times increase in the vapor pressure [14, 15].
In this work we report the results of a study of the effect of ligand substituents on the crystallochemical
characteristics and thermal behavior of copper(II) complexes with Schiff bases.
EXPERIMENTAL
Precursors. In the work the following reagents were used: propylenediamine and 2,2-dimethylpropylenediamine
(Merck, purity >98 %), CuCl2⋅2H2O (DalKhim, purity >97 %), acetylacetone (Hacac) (DalKhim, purity >98 %). Acetone,
toluene, and heptanes were used as solvents (Khimreaktiv, purity >97 %).
Synthesis of precursors. The [pda(Hacac)2] and [dmpda(Hacac)2] reagents were obtained by the procedure [4]. The
[dmpda(Hacac)2] precursor was first obtained by the interaction of 2,2-dimethylpropylenediamine (0.01 mol, 1.9 ml) with
acetylacetone (0.02 mol, 3.7 ml). The exothermal reaction is accompanied by the water vapor release, and the obtained
solution turns yellow. The solution was heated on a water bath (60 °C) for 2 h, then it was cooled using the CCl4/N2(l.)
mixture. The light yellow crystallized precipitate was twice recrystallized in heptane. The [dmpda(Hacac)2] yield is 60 %,
Tmelt = 84-86 °C. Calculated for C15H26O2N2 (M = 266.4 g/mol): C 67.6, H 9.8, N 10.5. Found: C 67.5, H 9.9, N 10.7. Ligand.
1
Н (500 MHz, 25 °C, ppm): 1.07 [s, (CH3)2C(CH2)2]; 1.89 [s, 2(CH3CNH–)]; 2.06 [s, 2(CH3CO)]; 3.15 [d, (CH3)2C(CH2)2,
3
13
JH–H = 6 Hz]; 4.98 [s, 2(CH)]; 11.18 [br, s, 2(NH)]. С NMR{ Н} (125.76 MHz, 25 °C, ppm): 18.93 [s, 2(CH3CNH–)];
1
23.59 [s, (CH3)2C(CH2)2]; 28.73 [s, 2(CH3C0)]; 35.76 [s, (CH3)2C(CH2)2]; 50.31 [s, (CH3)2C(CH2)2]; 95.68 [s, 2(CH)];
163.65 [s, 2(CO)]; 195.09 [s, 2(CNH)]. The [pda(Hacac)2] precursor was obtained by the interaction of propylenediamine
(0.01 mol, 1.6 ml) with acetylacetone (0.02 mol, 3.7 ml) and purified by the above described procedure. The ligand yield was
65 %, Tmelt = 91-93°C. Calculated for C13H22O2N2 (M = 238.3 g/mol): C 65.5, H 9.3, N 11.8. Found: C 65.3, H 9.3, N 11.7.
Synthesis of copper(II) complexes. Complexes 1 and 2 were synthesized using the procedure [4] by the interaction
of the corresponding ligand and freshly precipitated copper(II) hydroxide washed with acetone. In a day after the evaporation
of solvents the dry residue was placed into a funnel with paper filter and washed with benzene. The dark green solution
obtained was boiled down and recrystallized from heptane. The yields of complexes 1 and 2 were ∼80 %. For chelate 1
Tmelt = 121-122°C; calculated for C13H20O2N2Cu (M = 299.9 g/mol, Cu 21.2 %): C 52.1, H 6.7, N 9.3; found: C 52.0, H 6.8,
N 9.3. For chelate 2 Tmelt = 156-158°C; calculated for C15H24O2N2Cu (M = 327.9 g/mol, Cu 19.4 %): C 54.9, H 7.4, N 8.5;
found: C 55.0, H 7.6, N 8.4.
Identification of compounds. The C, H, N elemental analysis was performed on a Carlo-Erba 1106 (Italy) analyzer.
IR absorption spectra of the samples under study were measured on a Scimitar FTS 2000 spectrometer in the range 375-
–1
4000 cm . The samples were prepared by pressing the pellets with KBr. The IR spectral bands were assigned by comparing
1
13
them with the literature data [16]. Н and С NMR spectra of solutions in CDCl3 were measured at room temperature on
an AVANCE 500 BRUKER spectrometer. Chemical shifts were measured with respect to the chloroform signal and
recalculated with respect to TMS.
Single crystals suitable for XRD were grown by slow crystallization from the acetone solution. XRD of the
complexes was carried out by the standard procedure on an automated four-circle Bruker X8 Apex diffractometer equipped
with a two-dimensional CCD detector at a temperature of 150 K using molybdenum radiation (λ = 0.71073 Å) and a graphite
1068

TABLE 1. Crystallochemical Data and Experimental Conditions for the Ligand and Copper(II) Complexes
Stoichiometric formula
Molecular weight
Temperature, K
C15H26N2O2
226.4
C13H20N2O2Cu
299.9
C15H24N2O2Cu
327.9
123.0(2)
1.5418
150(2)
150(2)
Wavelength, Å
0.71073
Pbca
0.71073
Fdd2
Crystal symmetry,
space group
P21/c
a, b, c, Å
10.7416(4),
6.2329(2),
23.8430(8)
14.8672(12),
10.7597(7),
17.1581(14)
11.6434(4),
27.5742(8),
9.7641(3)
90, 96,134(3), 90
1587.2
90, 90, 90
2744.7(4)
90, 90, 90
3134.8
α, β, γ, deg
3
Volume, Å
3
Z, density dcal, mg/mm
Absorption coefficient, mm
F(000)
4, 1,115
8, 1,451
8, 1,390
–1
0.585
1.587
1.396
584.0
1256
1384
Crystal dimensions, mm
0.4835×0.2901×0.2198
from 7.46 to 133.52
0.45×0.38×0.15
from 2.37 to 25.35
0.20×0.12×0.12
from 2.82 to 30.50
θ range, deg
h, k, l ranges
–9 ≤ h ≤ 12,
–7 ≤ k ≤ 7,
–17 ≤ h ≤ 17,
–8 ≤ k ≤ 12,
–16 ≤ h ≤ 6,
–33 ≤ k ≤ 39,
–28 ≤ l ≤ 23
–20 ≤ l ≤ 20
–9 ≤ l ≤ 13
Number of meas. /
5820 / 2768 (0.0369)
15916 / 2473 (0.0409)
7267 / 2174 (0.0385)
indep. reflections (Rint)
θ data completeness, %
98.3 (2θ = 135°)
98.5 (2θ = 50°)
100.0 (2θ = 50°)
Maximum and minimum
absorption
0.8605 and 0.7470
0.7967 and 0.5352
0.8503 and 0.7676
Number of reflections /
restr. / parameters
2768 / 0 / 187
2473 / 0 / 167
2174 / 1 / 95
2
S-factor against F
1.049
1.070
1.051
R1 = 0.0489,
wR2 = 0.1284
R1 = 0.0434,
wR2 = 0.1095
R1 = 0.0251,
wR2 = 0.0594
R-factor [I > 2σ(I)]
R- factor (all data)
R1 = 0.0569,
wR2 = 0.1392
R1 = 0.0600,
wR2 = 0.1188
R1 = 0.0291,
wR2 = 0.0609
Max. and min. residual
0,24 and –0.22
1.278 and –0.598
0.272 and –0.221
–3
electron densities, e/Å
monochromator. Reflection intentities were measured by ϕ-scanning of narrow (0.5°) frames. Absorption correction was
applied semi-empirically using the SADABS program [17]. The structures were solved by a direct method and refined by the
full-matrix least squares technique in the anisotropic approximation for non-hydrogen ordered atoms using the SHELXTL
program package [17]. Details of the experiments and refinement are listed in Table 1. Hydrogen atoms are refined in the
rigid body approximation. CIF files containing full information on the structures studied have been deposited with CCDC
under
numbers
886503
(dmpda(Hacac)2),
886504
(Cu(pda(acac)2)),
and
886505
(Cu(dmpda(acac)2))
(www.ccdc.cam.ac.uk/data_reguest/cif).
Thermal analysis was performed on a Netzsch TG 209 F1 Iris analyzer using the Proteus analysis program package.
The portion weight was 10 mg. The experiment was carried out in the helium atmosphere (30.0 ml/min, open Al2O3 crucible,
10 °/min). Mass spectra of the complexes were measured on a high-resolution Thermo Scientific Double Focusing Sector
Mass Spectrometer (DFS HRMS); an argon/xenon mixture was used as the gas; the electron energy was 70 eV, with a direct
–7
introduction at T = 240 °C, P = 10 Torr. The work was carried out at the Chemical Service Center, Siberian Branch,
Russian Academy of Sciences.
1069

Fig. 1. Synthesis scheme of precursors.
Fig. 2. Possible tautomeric forms of [dmpda(Hacac)2] in solution.
RESULTS AND DISCISSION
Characterization of pda(Hacac) and dmpda(Hacac) ligands. Both precursors were obtained by the reaction
2 2
shown in Fig. 1, where R = H, CH3. In [4] the ligands were purified by recrystallization from water. The presence of water
can cause the destruction of the precursor, therefore the compounds that we obtained were purified by recrystallization from
heptane. This purification method provides an increase in the yield of the precursors up to 85 %.
The [dmpda(Hacac)2] compound obtained and purified for the first time was studied by single crystal XRD, IR
spectroscopy, and NMR spectrometry. It is possible to assume its existence in the solution as four tatomeric forms 1а-1d
(Fig. 2).
–1
The IR spectrum of the precursor exhibits the stretching vibrational bands ν(N–H, O–H) at 3425 cm and
–1
3226 cm , which indicates the existence of the complex in enol form 1b or 1с. Similar bands of the stretching vibrations
–1 –1
ν(N–H, O–H) at 3409 cm and 3212 cm are also present in the IR spectrum of [pda(Hacac)2]. The spectra of [pda(Hacac)2]
–1
and [dmpda(Hacac)2] contain intense bands in the region of 1610-1560 cm , which, according to the data of [18, 19], can be
assigned to ν(C=O)ас and ν(C=O)с vibrations.
The NMR spectrometric analysis of [dmpda(Hacac)2] shows that tautomer 1а is absent in the solutions studied. The
3
splitting of –СН2– proton signals associated with the–NH– group in a doublet with JH–H = 6 Hz gives evidence in favor of
the ligand existence in the solution in the form of tautomer 1с. This conclusion is confirmed by the comparison of the
1
13
chemical shifts measured in the Н and С NMR spectra and calculated using the ChemDraw Ultra 8.0 program. However,
a significant shift of the –NH– proton signal to the weak field gives grounds to assume the occurrence of the intramolecular
hydrogen bonds =N…H…O= and the formation of a pseudo-aromatic structure of 1d type.
Fig. 3. Structure of the [dmpda(Hacac)2] molecule.
1070

Fig. 4. Molecular structure of copper(II) complexes [Cu(pda(acac)2)] (a) and [Cu(dmpda(acac)2)] (b).
The structure of [dmpda(Hacac)2] (Fig. 3) was identified by the single crystal XRD method. Both acetoimine groups
in the precursor molecule have similar geometric characteristics. The Cβ–Cα(N) bond lengths (Cα(X) is the carbon atom
bonded to the X atom) are somewhat shorter than the Cβ–Cα(O) bond lengths. Their values are 1.3839(22) Å, 1.3816(23) Å
and 1.4152(23) Å, 1.4208(24) Å respectively. The C–O bond lengths are 1.2560(19) Å and 1.2536(22) Å, whereas for C–N
they are 1.3343(19) Å and 1.3351(21) Å. Both acetoimine moieties form six-membered rings due to the appearance of
intramolecular hydrogen bonds N–H…O with the lengths of 2.6514(16) Å and 2.6596(18) Å. Thus, it is possible to expect
that the precursor exists in form 1d, which is consistent with the NMR data.
Characterization of [Cu(pda(acac) )] and [Cu(dmpda(acac) )] complexes. Single crystals of [Cu(pda(acac)2)] (1)
2 2
and [Cu(dmpda(acac)2)] (2) were grown by the evaporation of the corresponding acetone solutions of the complexes. The
2+
molecules of the complexes consist of the Cu cation and tetradentate ligand anions ([pda(acac)2] or [dmpda(acac)2] )
2–
2–
coordinated to it (Fig. 4).
The distorted planar square environment of the copper cation is formed by two nitrogen atoms of the pda or dmpdа
groups and two oxygen atoms of the acac groups. The geometric parameters of the coordination core are summarized in
Table 2. The Cu–O chelate bond lengths are somewhat shorter in comparison with Cu–N. A distinction in the C–O and C–N
bond lengths does not exceed 0.04 Å in both complexes.
The structures of both complexes contain: two six-membered conjugated rings (CuOСССN) and one six-membered
ring (CuNСССN). In the structure of 1 one of the CuOСССN chelate rings is almost planar (with a bend angle along the
O(1)N(1) line of 5.5°), whereas the second chelate ring is bent at 12.0° (along the O(2)N(2) line). In the structure of 2 both
chelate rings are practically planar (with equal bend angles of 6.3°). A comparison of the structural parameters of copper(II)
chelates [Cu(pda(acac)2)] and [Cu(dmpda(acac)2)] with the literature data for [Cu(en(acac)2] [7, 8] shows that the pda and
dmpda substitution for the en moiety is accompanied by a distortion of the square planar geometry of the chelate node of the
central metal atom. The angles between the N(1)Cu(1)O(1) and N(2)Cu(1)O(2) planes located inside the chelate rings are
0.7° for [Cu(en(acac)2] [7, 8], 36.8° for [Cu(pda(acac)2)], and 37.4° for [Cu(dmpda(acac)2)].
Molecules in the crystals of copper(II) complexes with Schiff bases are packed by van der Waals contacts. Terminal
CH3 groups freely rotate in the organic ligands. The pda and dmpda substitution for en in the diimine moiety in the molecules
of copper(II) complexes is accompanied by a change in the type of molecular packing in the crystals. The crystal structure of
[Cu(en(acac)2] is composed of fragments containing two molecules located practically in parallel planes and shifted relative
to each other (the shortest distances between the copper atoms are 4.648 Å) [7, 8].
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TABLE 2. Interatomic Distances d (Å) and Bond Angles ω (deg.) for Complexes 1 and 2
1 [Cu(pda(acac)2)] 2 [Cu(dmpda(acac)2)]
Bond
d
Bond
d
Сu(1)–O(1)
Cu(1)–O(2)
Cu(1)–N(1)
Cu(1)–N(2)
1.903(2)
1.913(2)
1.940(3)
1.942(3)
Сu(1)–O(1)
Cu(1)–O(1)
Cu(1)–N(1)
Cu(1)–N(1)
1.909(1)
1.909(1)
1.943(2)
1.943(2)
i
i
Angle
Angle
ω
ω
i
O(1)–Cu(1)–O(2)
O(1)–Cu(1)–N(1)
O(2)–Cu(1)–N(1)
O(1)–Cu(1)–N(2)
O(2)–Cu(1)–N(2)
N(1)–Cu(1)–N(2)
89.81(10)
94.99(12)
152.41(12)
153.80(12)
94.44(11)
93.10(12)
O(1)–Cu(1)–O(1)
90.40(8)
94.63(6)
152.65(6)
152.65(6)
94.63(6)
93.12(9)
O(1)–Cu(1)–N(1)
i
O(1) –Cu(1)–N(1)
i
O(1)–Cu(1)–N(1)
i
O(1) –Cu(1)–N(1)
i
i
N(1) –Cu(1)–N(1)
i
Symmetry elements (–x, 1–y, z).
The molecules of complex 1 are located in the vertices of the primitive rectangular packing. The molecules of
complexes exist in the crystals in the form of two conformational isomers that are mirror-like bonded with each other (Fig. 5).
The shortest distance between the copper atoms is 5.586 Å.
Molecules in complex 2 are packed by van der Waals interactions and are located above each other with a shift
along the b/2 axis, forming stacks along the b axis (Fig. 6). The shortest distance between the copper atoms is 7.425 Å.
A similar packing type is also observed for the nickel complex with Schiff bases [20].
A comparison of the IR spectra of the precursors of (pda(Hacac)2) and (dmpda(Hacac)2) copper(II) complexes 1 and
–1
2 shows that broad bands in the region of 3430-3230 cm , which are present in the spectra of the precursors, are not observed
–1
in the spectra of 1 and 2 [21]. Intense characteristic bands in the region of 1610-1560 cm , which are present in the spectra of
(pda(Hacac)2) and (dmpda(Hacac)2), disappear in the spectra of copper(II) complexes. The appearance of new bands
–1 –1
corresponding to the ν(=C–O) vibrations at 1237 cm in the case of 1 and 1232 cm in the case of 2 indicates the formation
–1
of C–O–Cu bonds [22, 23]. New bands observed in the IR spectra of both complexes in the regions of 510-528 cm and 470-
–1
490 cm can be assigned to the ν(Cu–N) and ν(Cu–O) vibrations respectively [22].
Fig. 5. Molecular packing of [Cu(pda(acac)2)] in the
crystal.
Fig. 6. Molecular packing of [Cu(dmpda(acac)2)] in
the crystal.
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Fig. 7. Weight loss curves of [Cu(pda(acac)2)] 1;
[Cu(dmpda(acac)2)] 2; [Cu(en(acac)2)] 3.
TABLE 3. Metal-Containing Ions in the Mass Spectrum of Cu(pda(acac)2) and Cu(dmpda(acac)2) Compounds
Ion
m/z
Rel.
Ion
m/z
Rel. concentration
%
concentration, %
Compound 1
Compound 2
+
+
+
+
[CuL–C5H9NO]
[CuL–C6H9NO]
200.0
188.0
174.0
145.0
65.1
65.0
72.3
14.6
[CuL–C5H9NO]
[CuL–C6H9NO]
228.0
216.1
174.0
145.0
3.8
100
+
+
+
[CuL–C7H11NO]
[CuL–C9H16NO]
[CuL–C9H15NO]
[CuL–
+
45.6
9.7
C11H20NO]
+
+
Cu
63.0
10.1
Cu
63.0
5.7
Synthetic procedures were performed on a laboratory device for the synthesis with reaction medium volumes up to
3 l. The synthesis was supported by the Ministry of Education of the Russian Federation (Contract No. 14.604.21.0080 on
June 30, 2014; unique identifier PNI RFMEFI60414X0081).
Thermal properties of copper(II) complexes with Schiff bases. The thermogravimetric data for chelates 1, 2, and
also [Cu(en(acac)2] are presented in Fig. 7.
Compounds 1 and 2 are more volatile in comparison with 3 and some β-diketonate copper(II) derivatives [24-26].
The temperature of the 50 % weight loss is 485 K for Cu(i-acac)2 [25]; 490 K for Cu(Mei-acac)2 [25]; 516 K for 2; 520 K for
Cu(acac)2 [25]; 528 K for 1; 540 K for Cu(i-tmhd)2 [26]; 543 K for 3; and 550 K for Cu(tmhd)2 [26] (i-acac is 2-amino-
penen-4-onato(-), Mei-acac is 2-methylamino-penen-4-onato(-), i-tmhd is 2,2,6,6-tetramethyl-3-amino-hepten-5-onato(-),
tmhd is 2,2,6,6-tetramethyl-3,5-heptandionato(-)).
Under the TG experimental conditions complexes 1 and 3 quantitatively pass into the gas phase (the weight loss is
99.4 % for 1 and 99.5 % for 3), while 2 passes into the gas phase with small decomposition (the weight loss is 93.8 %).
+
In the mass spectra of both compounds the peaks of ions corresponding to the molecular forms [ML2] are observed
at m/z = 299.1 (100 %) for 1 and 327.0 (62.2 %) for 2. Under the electronic shock impact organic moieties are separated from
the complexes and the following metal-containing ions form (Table 3).
In the spectra of both compounds the peaks of ions of the same organic residues are observed at m/z = 111.0, 97.1,
55.0, and 43.0; there are also peaks corresponding to metallic copper at m/z = 63.0.
REFERENCES
1. W. H. Leung and C. M. Che, Inorg. Chem., 28, 4116-4120 (1989).
2. N. S. Enikolopyan, K. A. Bogdanova, and K. A. Askarov, Russ. Chem. Rev., 52, 13-18 (1983).
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3. A. M. El-Hendawy, A. H. Alkubaisi, A. El-Ghany, K. El-Kourashy, and M. N. Sharab, Polyhedron, 12, 2343-2347
(1993).
4. P. J. McCarthy, R. J. Hovey, K. Ueno, and A. E. Martell, J. Am. Chem. Soc., 77, 5820-5825 (1955).
5. N. Aksuner, E. Henden, I. Yilmaz, and A. Cukurovali, Dyes Pigm., 83, 211-216 (2009).
6. Y-P. Cai, C-Y. Su, A-W. Xu, B-S. Kang, Y-X. Tong, H-Q. Liu, and S. Jie, Polyhedron, 20, 657-661 (2001).
7. G. V. Girichev, N. I. Giricheva, N. P. Kuz`mina, Yu. S. Medvedev, and A. Yu. Rogachev, J. Struct. Chem., 49, No. 5,
837-849 (2008).
8. N. V. Tverdova, E. D Pelevina., N. I. Giricheva, G. V. Girichev, N. P. Kuzmina, and O. V. Kotova, J. Mol. Struct.,
1012, 151-161 (2012).
9. G. V. Girichev, N. I. Giricheva, N. P. Kuz`mina, and O. V. Kotova, J. Struct. Chem., 50, No. 1, 52-59 (2009).
10. R. C. Charles, J. Phys. Chem., 65, No. 3, 3383-3390 (1961).
11. Yu. V. Chumachenko, Chem. Sc. Candidate’s Diss., 02.00.01, Novosibirsk (1979).
12. G. I. Zharkova, S. I. Dorovskikh, S. V. Sysoev, I. P. Asanov, A. V. Panin, N. B. Morozova, and I. K. Igumenov, Surf.
Coat. Techn., 230, 290-296 (2013).
13. R. G. Charles, Thermochim. Acta, 38, 315-327 (1980).
14. P. A. Premkumar, R. Pankajavalli, O. M. Sreedharan, V. S. Raghunathan, K. S. Nagaraja, and C. Mallika, Mater. Lett.,
58, 2256-2260 (2004).
15. S. Arockiasamy, P. A. Premkumar, R. Pankajavalli, O. M. Sreedharan, V. S. Raghunathan, K. S. Nagaraja, and
C. Mallika, J. Mater. Sci., 41, 3383-3390 (2006).
16. APEX2 (Version 1.08), SAINT (Version 7.03), and SADABS (Version 2.11). Bruker Advanced X-ray Solutions, Bruker
AXS Inc., Madison, Wisconsin, USA (2004).
17. G. M. Sheldrick, Acta Crystallogr., A64, No. 1, 112-122 (2008).
18. Yue-Peng Cai, Cheng-Yong Su, An-wu Xu, Bei-Sheng Kang, Ye-Xiang Tong, Han-Qin Liu, and Sun Jie, Polyhedron,
20, 657-662 (2001).
19. A. E. Martell, R. N. Belford, and M. Calvin, J. Inorg. Nucl. Chem., 5, 170-176 (1958).
20. S. I. Dorovskikh, А. V. Alexeyev, N. V. Kuratieva, T. V. Basova, V. G. Kiselev, L. A. Sheludyakova, Yu. V. Shubin,
N. B. Morozova, and I. K. Igumenov, J. Organomet. Chem.; doi.org/10.1016/j.jorganchem.2013.05.001.
21. G. C. Percy and D. A. Thornton, J. Inorg. Nucl. Chem., 34, 3357-3362 (1972).
22. D. N. Kendall, Applied Infrared Spectroscopy, Reinhold Publishing, New York (1966).
23. S. M. Abn-EI-Wafa, R. A. Issa, and C. A. McAuliffe, Inorg. Chim. Acta, 99, 103-113 (1985).
24. W. S. Rees and C. R. Caballero, Adv. Mater. Optic. Electron., 1, 59-63 (1992).
25. I. A. Baidina, P. A. Stabnikov, A. D. Vasil`ev, S. A. Gromilov, and I. K. Igumenov, J. Struct. Chem., 45, No. 4, 671-
677 (2004).
26. P. A. Stabnikov, G. I. Zharkova, I. A. Baidina, S. V. Tkachev, V. V. Krisyuk, and I. K. Igumenov, Polyhedron, 26, 4445-
4449 (2007).
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