Syntheses, crystal structures, and properties of a Salamo-type Tetradentate Chelating Ligand and its Pentacoordinated Copper(II) complex

Article abstract of DOI:10.1002/zaac.201300254

A Salamo-type ligand 6,6'-diethoxy-2,2'-[1,1'-(ethylenedioxydinitrilo) dimethylidyne]diphenol (H₂L) and its pentacoordinate copper(II) complex [CuL(H₂O)] were synthesized and structurally characterized. The molecule of H₂L is located in a crystallographic inversion center and adopts E configuration with respect to the C=N bond. In the complex [CuL(H₂O)], the CuII atom has a tetragonally elongated square-pyramidal configuration with donor atoms N₂O₂ forming a perfect basal plane. And an infinite 2D layer supramolecular structure is formed through intermolecular C1-H1AO5 and C₂- H ₂AO₃ hydrogen bonding interactions.

Full text of DOI:10.1002/zaac.201300254

ARTICLE
DOI: 10.1002/zaac.201300254
Syntheses, Crystal Structures, and Properties of a Salamo-type Tetradentate
Chelating Ligand and Its Pentacoordinated Copper(II) Complex
Wen-Kui Dong,*[a] Zheng-Kun Wang,[a] Gang Li,[a] Meng-Meng Zhao,[a] Xiu-
Yan Dong,[a] and Sen-Hua Liu[a]
Keywords: Salamo-type ligand; Copper; Synthesis; Crystal structure; Property
Abstract. A Salamo-type ligand 6,6Ј-diethoxy-2,2Ј-[1,1Ј-(ethylene- bond. In the complex [CuL(H2O)], the CuII atom has a tetragonally
dioxydinitrilo)dimethylidyne]diphenol (H2L) and its pentacoordinate
elongated square-pyramidal configuration with donor atoms N2O2
copper(II) complex [CuL(H2O)] were synthesized and structurally forming a perfect basal plane. And an infinite 2D layer supramolecular
characterized. The molecule of H2L is located in a crystallographic structure is formed through intermolecular C1–H1A···O5 and C2–
inversion center and adopts E configuration with respect to the C=N H2A···O3 hydrogen bonding interactions.
Introduction
Experimental Section
Materials and Physical Measurements: 3-Ethoxysalicylaldehyde
was purchased from Alfa Aesar and used without further purification.
The other reagents and solvents were analytical grade reagents from
Tianjin Chemical Reagent Factory. Copper was detected by an IRIS
ER/S·WP-1 ICP atomic emission spectrometer. C, H, and N analyses
were carried out with a GmbH VariuoEL V3.00 automatic elemental
analyzer. Infrared (IR) spectra were recorded with a VERTEX-70 FT-
IR spectrophotometer, with samples prepared as KBr (500–4000 cm–1)
or CsI (100–500 cm–1) pellets. UV/Vis absorption spectra were re-
corded in 5.0ϫ10–5 and 1.0ϫ10–3 mol·L–1 DMF solution with a Shi-
madzu UV-2550 spectrometer. TG-DTA analyses were carried out at
a heating rate of 5 °C·min–1 with a ZRY-1P thermoanalyzer. Molar
conductance value measurement was carried out with a model DDS-
11D type conductivity bridge using 1.0ϫ10–3 mol·dm–3 solution in
DMF at 25 °C. X-ray single crystal structures were determined with a
Bruker Smart 1000 CCD area detector. Melting points were measured
by the use of a microscopic melting point apparatus made in Beijing
Taike Instrument Limited Company, and the thermometer was uncor-
rected.
Transition metal complexes having a Salen (N,NЈ-disalicyl-
ideneethylenediamine) ligand or its analogues are extensively
investigated because some of their metal complexes are used
in various organic reaction processes as catalysts,[1–5] models
of reaction centers of metalloenzymes,[6,7] nonlinear optical
materials,[8,9] and biological models in understanding the struc-
tures of biomolecules and biological processes.[10] Some of
these complexes have interesting magnetic properties.[11–15] To
improve such functions, chemical modifications of the ligand,
e.g., introduction of some functional groups or substitution of
some parts with appropriate ones, are effective and inevitable.
In particular, replacement of some atoms of the ligands with
other elements often changes its properties drastically.[16,17]
Recently, an O-alkyloxime analogue of Salen, 1,2-bis(salicyl-
ideneaminooxy)ethane (Salamo) has been reported, which
shows high stability under the conditions, where the imine ana-
logues suffer metathesis reaction of the C=N bonds.[18–21] The
syntheses and crystal structures of CuII complexes with Salamo
and 3-MeOSalamo have been studied,[18] but the CuII complex
with 3-EtOSalamo has not been reported so far. If ethoxy
groups are introduced to the 3-position of salicylidene moieties
of Salamo-type ligand, different and novel structure and prop-
erties of the resulting complex is expected. In the presented
work, the syntheses and crystal structures of a Salamo-type
Synthesis of H2L: The synthesis of H2L is shown in Scheme 1. To a
hot ethanol solution (10 mL) of 3-ethoxysalicylaldehyde (407.6 mg,
2.45 mmol) was added an ethanol solution (5 mL) of 1,2-bis(amino-
oxy)ethane (107.3 mg, 1.17 mmol). After the solution was stirred at
55 °C for 8 h, the reaction mixture was filtered, and washed success-
ively with ethanol and ethanol/hexane (1:4), respectively. The isolated
compound was dried under reduced pressure and purified with
recrystallization from ethanol to yield 324.5 mg of a colorless crystal-
ligand 6,6Ј-diethoxy-2,2Ј-[1,1Ј-(ethylenedioxydinitrilo)dimethyl- line solid. Yield, 71.7%. M.p. 113–115 °C. Elem. anal. for
idyne]diphenol (H2L) and its copper(II) complex [CuL(H2O)]
are reported.
* Prof. Dr. W.-K. Dong
E-Mail: dongwk@126.com
[a] School of Chemical and Biological Engineering
Lanzhou Jiaotong University
Lanzhou 730070, P. R. China
Scheme 1. Synthesis of H2L.
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ARTICLE
Table 1. Crystal data and structure refinement for H2L and the CuII complex.
H2L
[CuL(H2O)]
Empirical formula
Formula weight /g·mol–1
Temperature /K
C20H24N2O6
388.41
298(2)
C20H24CuN2O7
467.95
298(2)
Wavelength /Å
0.71073
0.71073
Crystal system
monoclinic
monoclinic
Space group
C2/c
P21/c
Unit cell dimensions /Å,°
a = 21.224(2)
b = 7.1190(8)
c = 13.748(1)
β = 109.213(1)
1961.5(3)
a = 12.604(1)
b = 13.214(2)
c = 14.206(2)
β = 115.535(2)
2134.8(4)
Volume /Å3
Z
4
4
Calculated density /mg·m–3
Absorption coefficient /mm–1
θ range for data collection /°
F(000)
1.315
0.098
3.04–25.01
824
1.456
1.066
2.36–25.02
972
Limiting indices
Crystal size /mm
–25,24 / –8,5 / –16,15
0.40ϫ0.34ϫ0.30
4721
1733
99.5
semi-empirical from equivalents
0.9713 and 0.9620
full-matrix least-squares on F2
1733 / 0 / 141
1.035
R1 = 0.0438, wR2 = 0.1003
R1 = 0.0847, wR2 = 0.1289
0.136 and –0.216
–14,8 / –15,15 / –16,16
0.42ϫ0.40ϫ0.35
10469
3736
99.4
semi-empirical from equivalents
0.7066 and 0.6629
full-matrix least-squares on F2
3736 / 0 / 273
1.051
R1 = 0.0376, wR2 = 0.0925
R1 = 0.0564, wR2 = 0.1088
0.358 and –0.630
Reflections collected
Independent reflection
Completeness to 25.01 or 25.02 /%
Absorption correction
Max, min Δρ /e·Å–3
Refinement method
Data / restraints / parameters
Goodness-of-fit for F2
Final R indices [I Ͼ 2σ (I)]
R indices (all data)
Largest difference peak and hole /e·Å–3
C20H24N2O6: calcd. C 61.8; H 6.2, N 7.2%; found: C 61.9; H 6.3; N
7.2%. H NMR (400 MHz, CDCl3): δ = 3.91 (s, –CH3, 6 H), 4.49 (s,
numbers CCDC-864889 for H2L and CCDC-864893 for the CuII com-
plex (Fax: +44-1223-336-033; E-Mail: deposit@ccdc.cam.ac.uk,
1
4 H), 4.64 (dd, J = 5.4, 1.5 Hz, –CH2–, 4 H), 6.83 (dd, J = 7.9, 1.9 Hz, http://www.ccdc.cam.ac.uk).
2 H), 6.86 (t, J = 7.9 Hz, 2 H), 6.91 (dd, J = 7.9, 1.9 Hz, 2 H), 8.26
(s, 2 H), 9.74 (s, 2 H) ppm.
Results and Discussions
The CuII complex [CuL(H2O)] with the Salamo-type ligand
H2L was obtained from ethanol/acetone solution as an aqua
complex, whereas some of other Salamo,[18] and related
(Salen,[22] Saltn,[23,24] Salbn[25] etc) complexes had a tetracoor-
dinate structure without aqua ligands.
CuII Complex [CuL(H2O)]: A solution of copper(II) aceate monohy-
drate (8.2 mg, 0.04 mmol) in ethanol (2 mL) was added dropwise to
a solution of H2L (15.8 mg, 0.04 mmol) in acetone (4 mL) at room
temperature. The color of the mixing solution turned to green immedi-
ately. The solution was allowed to stand at room temperature for about
one month. The solvent was partially evaporated and brown prismatic
single crystals suitable for X-ray crystallographic analysis were ob-
tained. Elem. anal. for C20H24N2O7Cu: calcd. C 51.33; H, 5.17; Cu,
13.58; N, 5.99%; found: C, 51.30; H, 5.19; Cu, 13.60; N, 5.94%.
Molar Conductivity
The CuII complex is soluble in DMF and DMSO, but not
soluble in ethanol, methanol, THF, acetone, and acetonitrile.
Meanwhile, the free ligand is soluble in all of the aforemen-
tioned solvents. The molar conductivity of the CuII complex at
25 °C of 10–3 mol·dm–3 DMF solution has a value of
5.3 Ω–1·cm2·mol–1. Compared with the molar conductivity in
different types of electrolytes in organic solvents reported by
Geary, it can be assumed that the CuII complex is a non-elec-
trolyte.[26]
X-ray Structure Determination of H2L and its CuII Complex: Sin-
gle crystals of H2L and [CuL(H2O)] with approximate dimensions of
0.40ϫ0.34ϫ0.30 mm3 and 0.42ϫ0.40ϫ0.35 mm3, respectively,
were placed on a Bruker Smart 1000 CCD area detector. The diffrac-
tion data were collected using graphite monochromated Mo-Kα radia-
tion (λ = 0.71073 Å) at 298(2)
K. The structures were solved using SHELXL-97 and Fourier differ-
ence techniques, and refined by full-matrix least-squares on F2. All
hydrogen atoms were added in the calculated positions. The crystal
data and structure refinement for H2L and the CuII complex are given
in Table 1.
FT-IR Spectroscopy
Crystallographic data (excluding structure factors) for the structures in
this paper have been deposited with the Cambridge Crystallographic
Data Centre, CCDC, 12 Union Road, Cambridge CB21EZ, UK. Copies
The most important FT-IR spectroscopic data for H2L and
[CuL(H2O)] are given in Table 2. The free ligand H2L exhibits
of the data can be obtained free of charge on quoting the depository a characteristic C=N stretching band at 1604 cm–1, while the
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Salamo-type Tetradentate Chelating Ligand and Its Pentacoordinated Copper(II) Complex
Table 2. Main IR spectroscopic data /cm–1 for H2L and its CuII complex.
Compound
ν(C=N)
ν(Ar–O)
ν(Cu–O)
ν(Cu–N)
ν(O–H)
δ(H2O)
ρ(H2O)
H2L
[CuL(H2O)]
1604
1592
1246
1224
–
435
–
474
3432
3408
–
1592
–
560
C=N of Cu(II) complex is observed at 1592 cm–1. The C=N
A weak absorption peak at 627 nm is observed in
stretching frequency is shifted to a lower frequency by ca. the UV/Vis spectrum of the CuII complex in DMF
12 cm–1 upon complexation, indicating a decrease in the C=N (1.0ϫ10–3 mol·L–1), which can be assigned to d–d transition
bond order due to the coordinated bonds of copper(II) ions of the CuII complex. These transition energies are smaller
with the oxime nitrogen lone pair.[27]
than those of the corresponding Salen or Salamo-type
The Ar–O stretching frequency appears as a strong band in complexes [Cu(Salen)] 565 nm, [Cu(Salamo)] 641 nm, and
the range of 1263–1213 cm–1 as reported for similar li- [Cu(3-MeOSalamo)] 632 nm.[18]
gands.[28–30] This band occurs at 1246 cm–1 for H2L, and at
1224 cm–1 for the Cu(II) complex. The Ar–O stretching fre-
quency is shifted to lower frequency, indicating that the Cu–O
Thermal Properties
bond was formed between the Cu(II) ions and oxygen atoms
of the phenolic groups.[28,31] In addition, the infrared spectrum
of [CuL(H2O)] shows the expected strong absorption bands
due to ν(O–H) at ca. 3408 cm–1, δ(H2O) at ca. 1592 cm–1, and
ρ(H2O) at ca. 560 cm–1, which are the evidences for the exis-
tence of coordinated water molecules.[32]
The far-IR spectrum of the CuII complex was measured
(500–100 cm–1) to identify frequencies due to Cu–O and Cu–
N bonds. The (Cu–O) and (Cu–N) frequencies are at 435 and
474 cm–1, respectively.[33,34] As pointed out by Percy and
Thornton,[31] the metal–oxygen and metal–nitrogen frequency
assignments are quite difficult.
The free ligand H2L has a small sharp endothermic peak at
114 °C in DTA curve, with no weight loss in the TG curve,
which is its melting point. On further heating, the free ligand
H2L has a exothermic peak at 276 °C, with a weight loss in
the TG curve, and the ligand decomposes completely by one
step. The thermal decomposition process of the CuII complex
can be divided into three stages. The initial weight loss occurs
in the range 120–138 °C for the CuII complex, corresponding
to an endothermic peak, and the TG curve shows that the
weight loss corresponding to this temperature range is 5.0%
that roughly coincides with the values of 4.6%, calculated for
the loss of one water molecule. On further heating, one exo-
thermic peak appears at 287.8 °C for the CuII complex in the
DTA curve, and a continued weight loss occurs in the TG
curve. Subsequently, the second strong exothermic peak at
UV/Vis Spectroscopy
UV/Vis absorption spectra of H2L and its CuII complex were 342.6 °C for the CuII complex is accompanied with further de-
determined in 5.0ϫ10–5 mol·L–1 DMF solution (Table 3). Ab- composition of the complex, and the final solid products are
sorptions of the CuII complex are obviously different from H2L likely to CuO with a residual value of 19.7% for the CuII
upon complexation. The UV/Vis spectrum of the free ligand complex when the temperature is above 650 °C.
H2L exhibits two absorption peaks at approximately 277 and
319 nm. The former absorption peak at 277 nm can be as-
signed to the π–π* transition of the benzene rings and the latter
Description of the Crystal Structure of H2L
at 319 nm can be attributed to the intraligand π–π* transition
The single crystal structure of H2L was determined by
X-ray crystallography. The molecular structure of H2L is
shown in Figure 1. Selected bond lengths and angles are listed
in Table 4.
of the oxime C=N group.[35]
Table 3. UV/Vis spectra of H2L and its CuII complex in DMF
(5.0ϫ10–5 mol·L–1).
Compound
H2L
λmax /nm ε /L·mol–1·cm–1 λmax /nm ε /L·mol–1·cm–1
277
40.7
319
386
10.6
[CuL(H2O)] 282
1262
451.0
Compared with the absorption peak of the ligand, the corre-
sponding absorption peak at 282 nm is observed in the CuII
complex, which is bathochromically shifted by ca. 5 nm.
Meanwhile, the absorption band at about 319 nm disappears
from the UV/Vis spectrum of the CuII complex, which indi-
cates that the oxime nitrogen atoms are involved in coordina-
tion to the CuII atom.[36] In addition, the new band observed
at 386 nm for the CuII complex is assigned to that of LǞM
charge-transfer transition, which is characteristic of the transi-
tion metal complexes with N2O2 coordination spheres.[16]
Figure 1. Molecule structure and atom numberings of H2L. Thermal
ellipsoids are plotted at 30% probability level.
The crystal structure of H2L is only built up by the
C20H24N2O6 molecules, in which all bond lengths and angles
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Table 4. Selected bond lengths /Å and angles /° for H2L.
Bond lengths
N1–C2
N1–O1
N1–O1Ј’
O1–C1
O1Ј–C1Ј
O2–C4
1.266(3)
1.436(9)
1.44(1)
1.43(1)
1.423(1)
1.359(2)
O3–C5
1.364(2)
1.427(3)
1.52(1)
1.47(1)
1.453(3)
1.390(3)
C3–C8
C4–C5
C5–C6
C6–C7
C7–C8
C9–C10
1.395(3)
O3–C9
1.398(3)
1.373(3)
1.387(3)
1.361(3)
1.499(3)
C1–C1#1
C1Ј–C1Ј#1
C2–C3
C3–C4
Bond angles
C2–N1–O1
111.3(5)
110.5(5)
25.0(4)
111.7(7)
110.5(8)
117.4(2)
109.1(6)
114.3(7)
N1–C2–C3
C4–C3–C8
C4–C3–C2
C8–C3–C2
O2–C4–C3
O2–C4–C5
C3–C4–C5
121.1(2)
118.8(2)
121.7(2)
119.6(2)
122.8(2)
117.1(2)
120.2(2)
O3–C5–C6
O3–C5–C4
C6–C5–C4
C5–C6–C7
C8–C7–C6
C7–C8–C3
O3–C9–C10
125.7(2)
114.9(2)
119.4(2)
120.8(2)
119.7(2)
121.2(2)
107.9(2)
C2–N1–O1Ј
O1–N1–O1Ј
C1–O1–N1
C1Ј–O1Ј–N1
C5–O3–C9
O1–C1–C1#1
O1Ј–C1Ј–C1Ј#1
Symmetry transformations used to generate equivalent atoms: #1 –x+1, –y+1, –z+1.
are in normal ranges. The molecule crystallizes in the mono- N2O2 [Cu1–O5 = 928(2); Cu1–O3 = 1.947(2); Cu1–N1 =
clinic system, space group C2/c, with four crystallographically 1.975(3); Cu1–N2 = 2.037(2) Å] forming a perfect basal plane
equivalent molecules in the unit cell. The molecule of H2L, and the apical weak bond Cu1–O7 [.249(2) Å][39] being almost
lies across a crystallographic inversion center and adopts an E perpendicular to this plane. The CuII atom is displaced by
configuration with respect to the C=N bond. This is similar 0.196(3) Å toward the bridging oxygen (O7) atom from the
to what was observed in our previously reported bis-oxime basal plane of the donor atoms.
compounds.[37,38] In the molecule, the two oxime groups with
The dihedral angle between the coordination plane of
the adjacent benzene ring forming dihedral angles of 10.11(3)° O3–Cu1–N1 and that of O5–Cu1–N2 is 16.27(3)°. The ethyl-
and 9.58(4)°. Within the molecule, the planar units are parallel enedioxime carbons C1 and C2 are also buckled asymmetri-
but extend in opposite directions from the methylene bridge. cally from the Cu1–N1–N2 plane, with the displacement for
The two benzene rings are parallel to each other and with the C2 being 1.455(3) Å toward the bridging molecule and for C1
distance of 0.008(2) Å.
being only 0.791(2) Å in the same direction. Whereas Cu–O
distances are nearly equal [Cu1–O5 = 1.928(2) Å, Cu1–O3 =
1.947(2) Å], the Cu–N shows significant differences [Cu1–N2
= 2.037(2) Å, Cu1–N1 = 1.975(3) Å]. It is noteworthy that the
Cu–N bond lengths are considerably longer than the Cu–O
bond lengths, the length of Cu–O7 should be attributed to the
involvement of H2O molecule in the complex formation; sim-
ilar elongation of the M–O bond has also been observed in the
complex [Co(Salen)].[40]
Description of the Crystal Structure of the CuII Complex
The molecular structure of the [CuL(H2O)] is shown in Fig-
ure 2. Selected bond lengths and angles are given in Table 5.
Supramolecular Interactions
In the crystal structure of H2L, two intramolecular
O2–H2···N1 hydrogen bonds involving the hydroxyl groups
and oxime nitrogen atoms generate S(6) ring motifs (C2/N1/
H2/O2/C4/C3) in each molecule. Moreover, a pair of intermo-
lecular C2–H2A···O1 hydrogen bonds link neighboring mole-
cules into R22(8) ring graph-motifs (C2/H2A/O1/N1/C2/H2A/
O1/N1). Simultaneously, this linkage is further stabilized by a
pair of intermolecular C7–H7···O2 hydrogen bonds to form an
infinite one-dimensional supramolecular ribbon structure (Fig-
ure 3 and Table 6).
Figure 2. Molecular structure and atom numberings of the CuII com-
plex. Thermal ellipsoids are plotted at 30% probability level. (hydro-
gen atoms are omitted for clarity).
The introduction of a coordinated water molecule in the CuII
X-ray crystallographic analysis of [CuL(H2O)] reveals for- complex successfully leads to the assembly of the [CuL(H2O)]
mation of a mononuclear structure. The CuII complex crys- units by intermolecular hydrogen bonds. As illustrated in Fig-
tallizes in the monoclinic system, space group P21/c, and Z = ure 4 and Table 7, five intermolecular hydrogen bonds,
4. In the complex [CuL(H2O)], the CuII atom has a tetragonally O7–H7C···O3, O7–H7C···O4, O7–H7D···O3, O7–H7D···O5,
elongated square-pyramidal configuration with donor atoms and O7–H7D···O6 are formed. One of the water protons
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Salamo-type Tetradentate Chelating Ligand and Its Pentacoordinated Copper(II) Complex
Table 5. Selected bond lengths /Å and angles /° for the CuII complex.
Bond lengths
Cu1–O5
Cu1–N2
1.928(2)
2.037(2)
Cu1–O3
Cu1–O7
1.947(2)
2.249(2)
Cu1–N1
1.975(3)
Bond angles
O5–Cu1–O3
O5–Cu1–N1
O3–Cu1–N1
O5–Cu1–N2
O3–Cu1–N2
N1–Cu1–N2
86.87(8)
165.2(1)
87.3(1)
87.79(9)
170.19(9)
95.9(1)
O5–Cu1–O7
O3–Cu1–O7
N1–Cu1–O7
N2–Cu1–O7
C3–N1–Cu1
97.90(8)
93.16(8)
96.01(9)
95.73(9)
127.2(2)
O1–N1–Cu1
C12–N2–Cu1
O2–N2–Cu1
C5–O3–Cu1
C14–O5–Cu1
120.7(2)
124.9(2)
126.4(2)
127.9(2)
129.4(2)
Figure 4. Hydrogen bonding interactions of the CuII complex (hydro-
gen atoms, except those forming hydrogen bonds, are omitted for clar-
ity).
Figure 3. Hydrogen bonding interactions of H2L (hydrogen atoms, ex-
cept those forming hydrogen bonds, are omitted for clarity).
Table 6. Intermolecular hydrogen bonds /Å,° for H2L.
D–H···A
d(D–H) d(H···A) ϽDHA d(D···A) Symmetry
code
O2–H2···N1
C2–H2A···O1 0.920
C7–H7···O2 0.930
0.821
1.898
2.456
2.625
145
173
132
2.615(3) x, y, z
3.380(4) 1–x, –y, 1–z
3.324(4) 1–x, 1–y, 1–z
(–O7H7C) of the coordinated water molecule is hydrogen
bound to coordinated phenolic oxygen atoms (O3) and the eth-
oxyl oxygen atoms (O4) of the ligand L2– unit, respectively.
The other of water proton –O7H7D is hydrogen bound to both
of coordinated phenolic oxygen atoms (O3 and O5) and the
ethoxyl oxygen atom (O6) of L2– unit, respectively. Conse-
quently, these hydrogen bonds interactions have stabilized a
pair of complex molecules to form a dimer unit with a nearest
Cu···Cu distance of 4.874 Å. Furthermore, every dimer further
links four other adjacent dimer units into an infinite 2D layer
supramolecular structure on the bc crystallographic plane by
Figure 5. View of the 2D-layer supramolecular structure within the
CuII complex on the bc crystallographic plane (hydrogen atoms, except
those forming hydrogen bonds, are omitted for clarity).
Table 7. Intermolecular hydrogen bonds /Å,° for the CuII complex.
D–H···A
d(D–H)
d(H···A)
ϽDHA
d(D···A)
Symmetry code
O7–H7C···O3
O7–H7C···O4
O7–H7D···O3
O7–H7D···O5
O7–H7D···O6
C2–H2A···O3
C1–H1A···O5
0.850
0.850
0.850
0.850
0.850
0.970
0.970
2.510
2.060
2.530
2.010
2.530
2.530
2.638
109
178
107
178
112
132
136
2.902(3)
2.908(3)
2.902(3)
2.859(3)
2.954(4)
3.264(4)
3.403(2)
1–x, 2–y, –z
1–x, 2–y, –z
1–x, 2–y, –z
1–x, 2–y, –z
1–x, 2–y, –z
1–x, 1/2+y, 1/2–z
1–x, 1/2+y, 1/2–z
Z. Anorg. Allg. Chem. 2013, 2263–2268
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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W.-K. Dong et al.
ARTICLE
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Conclusions
A new Salamo-type ligand H2L {6,6Ј-diethoxy-2,2Ј-[1,1Ј-
(ethylenedioxydinitrilo)dimethylidyne]diphenol} and its cop-
per(II) complex [CuL(H2O)] are reported. In the crystal struc-
ture of H2L, an infinite one-dimensional supramolecular ribbon
structure is formed by O···H–N and C–H···O hydrogen bonding
interactions. Additionally, an infinite 2D-layer supramolecular
structure is formed through intermolecular C1–H1A···O5 and
C2–H2A···O3 hydrogen bonding interactions.
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Acknowledgements
This work was supported by the National Natural Science Foundation
of China, the Fundamental Research Funds for the Gansu Province
Universities (212086), and the Science and Technology Support Funds
of Lanzhou Jiaotong University (ZC2012003), which are gratefully
acknowledged.
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Received: May 18, 2013
Published Online: August 15, 2013
2268
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Z. Anorg. Allg. Chem. 2013, 2263–2268