Synthesis, structure and properties of a novel Cu(II) complex constructed from designed ferrocenyl ligand

Article abstract of DOI:10.1080/15533170903228570

The treatment of Cu(NO₃)₂ 3H₂O with 3-carboxymethylamino-1-ferrocenyl-2-buten-1-one (FcC(O)CH = C(CH ₃)NHCH₂ COOH) in the presence of 1,10-phenantholine (phen) in methanol solution resulted in a novel

Full text of DOI:10.1080/15533170903228570

Synthesis and Reactivity in Inorganic, Metal-Organic, and Nano-Metal Chemistry, 39:489–494, 2009
Copyright © Taylor & Francis Group, LLC
ISSN: 1553-3174 print / 1553-3182 online
DOI: 10.1080/15533170903228570
Synthesis, Structure and Properties of a Novel Cu(II)
Complex Constructed from Designed Ferrocenyl Ligand
Li Hua Yan, Zi Feng Li, Gang Li, Li Peng Wang, and Lu Zhu
Department of Chemistry, Zhengzhou University, Zhengzhou, P. R. China
mal and electrochemical properties of the copper complex
3
The treatment of Cu(NO
amino-1-ferrocenyl-2-buten-1-one (FcC(O)CH=C(CH
3
)
2
· 3H
2
O with 3-carboxymethyl- [Cu(η -FcC(O)CH=C(CH3)NCH2COO)(phen)]· 1.5H2O (1).
3 2
)NHCH
COOH) in the presence of 1,10-phenantholine (phen) in EXPERIMENTAL
3
methanol solution resulted in a novel complex [Cu(η -FcC(O)CH=
C(CH
3
)NCH
2
COO)(phen)]· 1.5H
2
O (1). The molecular structure General Procedures
of complex 1 has been characterized by elemental analysis, IR and
single crystal X-ray diffraction. Its thermal and electrochemical
properties are presented.
All chemicals were of reagent grade quality obtained from
commercial sources and used without further purification. Lig-
and FcC(O)CH=C(CH3)NHCH2COOH was prepared accord-
ing to the literature methods.[ Its sodium salt was prepared by
reaction with sodium methoxide.
19]
Keywords copper(II) complex, structure, designed ferrocenyl
ligand, thermal and electrochemical properties
IR spectra were recorded on a Nicolet NEXUS 470-FTIR
−1
spectrophotometer as KBr pellets in the 400–4000 cm region.
Elemental analyses (C, H and N) were carried out on a FLASH
EA1112 elemental analyzer. TG-DSC measurements were per-
INTRODUCTION
Ferrocenyl complexes have attracted continuously much in-
terest in the field of coordination chemistry due to their po-
tential applications such as nonlinear optical materials, mag-
◦
◦
formed by heating the sample from 20 C to 650 C at a rate of
◦
−1
[
1−5]
10 C/min in air on a NETZSCH STA 409PC differential ther-
mal analyzer. Cyclic voltammetry studies were recorded with an
CHI650 electrochemical analyzer utilizing the three-electrode
configuration of a Pt working electrode, a Pt auxiliary elec-
trode, and a commercially available saturated calomel electrode
as the reference electrode with a pure N2 gas inlet and outlet.
The measurements were performed in DMF solution contain-
ing tetraethyl ammonium perchlorate (n-Bu4NClO4) (0.1 mol ·
netic materials and catalysis and so on.
Therefore the de-
sign of various ferrocenyl ligands to build up desired com-
plexes is very important. Up to date, two kinds of ferro-
[
6−11]
cenyl compounds—ferrocene-substituted carboxylate
and
12−15]
have mainly been used
[
pyridine-containing ferrocene
to construct novel complexes bearing ferrocene group. Re-
cently, ferrocene-containing enaminones have also been ex-
[16−18]
plored in this context,
with ferrocenyl enaminones are scarce.
but the reported complexes
−
3
[19]
dm ) as supporting electrolyte, which has a 50 ms pulse width
Herein, we se-
and a 20 ms sample width. The potential was scanned from +0.0
lected one novel ferrocenyl enaminone-based carboxylate
compound, 3-carboxymethylamino-1-ferrocenyl-2-buten-1-one
−1
to +1.2 V at scan rate of 30 mV s
.
Caution ! Although no problems were encountered in this
work, the salt perchlorates are potentially explosive. They
should be prepared in small quantities and handled with care.
(
FcC(O)CH=C(CH3)NHCH2COOH), and surmised that having
both enaminone and carboxylate groups within the same ligand
might generate interesting structures. To our knowledge so far,
no article on crystalline complex constructed from organometal-
lic enaminone-based carboxylate ligand has appeared, and
in this paper we report the synthesis, crystal structure, ther-
3
Preparation of [Cu(␩ -FcC(O)CH=C(CH3)NCH2COO)
(
phen)]·1.5H2O (1)
FcC(O)CH=C(CH3)NHCH2COONa (16.4 mg, 0.05 mmol)
in 3 mL of methanol solution was added dropwise to the so-
Received 6 May 2009; accepted 5 June 2009.
We gratefully acknowledge the financial support by the National
lution of 3 mL of methanol of Cu(NO3)2·3H2O (12.1 mg,
Natural Science Foundation of China (20501017), and by the Key 0.05 mmol). Then 2 mL of methanol of phen (10 mg,
Project of Chinese Ministry of Education (207067) and by the Scien-
tific Research Foundation for the Returned Overseas Chinese Scholars
of Chinese Ministry of Education.
0
.05 mmol) was added slowly to the former mixture. The
dark brown resulting mixed solution was stirred uniformly;
subsequently the filtrate was allowed to stand at room
temperature in the dark. Good quality blue-green crystals
of [Cu(η -FcC(O)CH=C(CH3)NCH2COO)(phen)]·1.5H2O (1)
Address correspondence to Gang Li, Department of Chem-
istry, Zhengzhou University, Zhengzhou 450052, P. R. China.
E-mail: gangli@zzu.edu.cn
3
489

490
L. H. YAN ET AL.
TABLE 1
Crystallographic data for 1
Compound
1
Formula
Fw
C28H26CuFeN3O4.5
595.91
Crystal syst
Space group
Crystal size (mm)
Triclinic
P-1
0.20 × 0.18 × 0.17
10.722(2)
11.043(2)
12.180(2)
70.91(3)
82.18(3)
83.27(3)
1346.1(5)
2
˚
a (A)
˚
b (A)
˚
c (A)
α (deg)
β (deg)
γ (deg)
˚
3
V (A )
5
4
SCH. 1. [Fc= (η -C5H5)Fe(C5H4 − η ); NN=phen].
Z
Dc (mg m−3)
F(000)
1.470
612
1.369
data are deposited at Cambridge Crystallographic Data Centre,
CCDC 693234.
µ (mm−1)
Theta range for data collection 1.78 to 25.50
RESULTS AND DISCUSSION
Limiting indices
−12<=h<=12,
−
13<=k<=0,
14<=l<=13
Synthesis
−
The blue-green crystalline complex 1 was prepared in good
Reflections collected/unique
Max. and min. transmission
Data/restraints/parameters
Goodness-of-fit on F2
4504/4504 [R(int) = 0.0000] yield, as summarized in Scheme 1. The key of synthesis of
0.8006 and 0.7714
4504/6/357
1.084
the complex 1 is the avoidance of light, as noted in earlier
studies.[
10,14]
The air-stable compound 1 was characterized by
satisfactory C, H and N microanalysis, IR spectra, and finally by
Final R indices [I>2sigma(I)] R1 = 0.0621, wR2 = 0.1627 single crystal X-ray diffraction. The compound was insoluble
R indices (all data)
R1 = 0.0780, wR2 = 0.1759 in non-polar solvents such as in MeOH, EtOH or MeCN, but it
˚
−3
)
ꢀρmax and ꢀ ρmin (e A
0.862 and −0.486
was soluble in the highly polar solvents as DMSO or DMF.
The Molecular Structure of Crystalline Complex 1
The molecular structure of the crystalline compound 1 is
shown in Figure 1; selected geometrical parameters are listed in
Table 2.
were obtained after two days. Yield: 78%. Anal. calcd. for
C28H26N3O4.5FeCu: C, 56.43; H, 4.40; N, 7.05%. Found:
−1
C, 56.31; H, 4.52; N, 7.01%. IR (cm , KBr): 3431s, 3092m,
1
1
612s, 1505s, 1430s, 1386w, 1308m, 1286w, 1235w, 1142w,
104m, 932w, 848m, 811w, 776w, 730m, 640w, 585w, 482w.
TABLE 2
˚
Bond lengths (A) and bond angle (deg) of complex 1
X-ray Crystallography
Cu(1)-O(1)
1.905(4)
Cu(1)-N(1)
1.920(4)
Crystal data and experimental details for compound 1 are
contained in Table 1. All measurements were made on a Bruker
Smart 1000 diffractometer with a graphite-monochromated
MoKα radiation (λ = 0.71073 A). Red prismatic single crystal
Cu(1)-O(2)
Cu(1)-N(2)
O(1)-C(11)
O(2)-C(16)
C(10)-C(11)
C(12)-C(13)
N(3)-Cu(1)-N(2)
O(1)-Cu(1)-O(2)
O(1)-Cu(1)-N(3)
O(2)-Cu(1)-N(3)
N(1)-Cu(1)-N(2)
C(13)-N(1)-C(15)
C(15)-N(1)-Cu(1)
O(1)-C(11)-C(10)
N(1)-C(13)-C(12)
1.982(4)
Cu(1)-N(3)
N(1)-C(13)
N(1)-C(15)
O(3)-C(16)
C(11)-C(12)
2.040(5)
2.277(4)
1.291(6)
1.269(7)
1.478(7)
1.420(7) N(1)-Cu(1)-O(2)
77.39(17) O(1)-Cu(1)-N(1)
165.71(16) N(1)-Cu(1)-N(3)
89.82(17) O(1)-Cu(1)-N(2)
90.40(18) O(2)-Cu(1)-N(2)
108.95(17) C(11)-C(12)-C(13)
1.306(6)
1.464(7)
1.243(7)
1.386(7)
83.31(17)
94.80(17)
171.32(18)
99.60(16)
94.39(17)
126.8(5)
126.3(3)
125.2(5)
119.7(4)
117.5(4)
˚
of (0.20 × 0.18 × 0.17 mm) was selected and mounted on a glass
fiber. All data were collected at a temperature of 291(2) K using
the ω -2θ scan technique and corrected for Lorenz-polarization
effects. A correction for secondary extinction was applied. The
structure was solved by direct methods and expanded using the
Fourier technique. The non-hydrogen atoms were refined with
anisotropic thermal parameters. Hydrogen atoms were included
but not refined. The final cycle of full-matrix least squares
refinement was based on 4504 observed reflections and 357
variable parameters. All calculations were performed using the
SHELX-97 crystallographic software package.[ The crystal
121.1(4)
112.4(3)
115.0(4)
121.5(4)
C(13)-N(1)-Cu(1)
O(1)-C(11)-C(12)
C(12)-C(11)-C(10)
C(12)-C(13)-C(14)
20]

CU(II) COMPLEX FROM FERROCENYL LIGAND
491
FIG. 1. The molecular structure of complex 1 (H atoms and solvent molecule omitted for clarity).
Single-crystal X-ray diffraction measurement shows that the by the four atoms N1, N3, O1 and O2 (the mean deviation from
˚
crystal structure of the complex can be viewed as made up of the plane is 0.0627 A), while Cu1 is located above the plane
3
˚
Cu(η -FcC(O)CH2 C(CH3)NCH2COO)(phen)] unit and non- (distance from the center of the plane being 0.191 A). The in-
coordinated water molecules. The five-coordinate copper(II) plane Cu1-N bond lengths are within the range 1.920–2.040 A.
atom displays a slightly distorted square-pyramidal geometry The in-plane Cu1-O1 and Cu1-O2 distances are 1.905 A and
surrounded by two nitrogen atoms N2 and N3 from phen and 1.982 A, respectively. The axial bond distance of Cu1-N2 is
three atoms, O1, N1 and O2 from one deprotonated ligand [η - 2.277 A, which is significantly longer than the bond distances
FcC(O)CH2 =C(CH3)NCH2COO] . The plane (I) is defined in the plane I. This interesting feature is unexpected, because
[
˚
˚
˚
˚
3
2−
FIG. 2. The dimeric unit of complex 1 supported by weak hydrogen-bonding and strong π − π stacking.

492
L. H. YAN ET AL.
FIG. 3. Crystal packing of complex 1 in the solid.
the axial bond in square-pyramidal Cu(II) is usually long and the existence of π − π stacking interactions. Additionally,
˚
varies between 2.12 and 2.6 A for O or N coordination, due to there are weak C H · · · O hydrogen bonds between the
Jahn-Teller effects.[ It is to be pointed out that the O1-C11, neighboring units, which originate from CH of one [Cu(η -
21]
3
C11-C12, C12-C13 and C13-N1 bond distances are of 1.296, FcC(O)CH2 C(CH3)NCH2COO)(phen)] unit with O from
˚
3
1
.386, 1.420 and 1.306 A, respectively. These suggest that the the carbonyl group of neighboring [Cu(η -FcC(O)CH2=C
O C C C N system of the complex has more delocalization (CH3)NCH2COO)(phen)] unit. Thus, the dimeric Cu(II) unit
than that of the corresponding ligand.[
19]
was built up.
Interestingly, it can be seen from Figure 2, the phen rings of
Within the ferrocene fragments, the C C distances, Fe–Cring
3
neighboring [Cu(η -FcC(O)CH2 =C(CH3)NCH2COO)(phen)] distances and C C C angles are all similar to those reported
units are face-to-face arranged, while the distance between in the literature.[ The cyclopentadienyl rings are planar and
8]
˚
◦
◦
the two rings is 4.210 A and dihedral angle is 0 indicating parallel with a dihedral angle of 3.8 . The bond lengths and
FIG. 4. Cyclic voltammogram of complex 1 (right) and the corresponding ferrocenyl ligand, 3-carboxymethylamino-1-ferrocenyl-2-buten-1-one (left) (∼1.0 ×
−
3
−
1
1
0
M) in DMF containing n-Bu4NClO4 (0.1 M) at a scanning rate of 30 mV s (vs. SCE).

CU(II) COMPLEX FROM FERROCENYL LIGAND
493
FIG. 5. Thermogravimetric curve of complex 1.
angles within the phen ligand are also unexceptional and close potential difference of both peaks is 0.066 V. Obviously, Cu(II)
to those reported in the literature. ion has a significant effect to oxidation-reduction potentials
In addition, in the solid-state, a large number of crystalliza- of the ferrocenyl group in the complex. Thus, both oxidation
tion water molecules can form hydrogen bonds with the sur- and reduction electric potentials have a marked shift to the
rounding units. Therefore a stable three-dimensional solid-state lower potential. The migration rates of one oxidation peak
structure is constituted (Figure 3).
(0.192 V) and of the reduction peak (0.207 V) are very close,
which resulted in the slight change of the electric potential
difference.
IR Spectroscopy
According to the references,[9,10] the characteristic IR bands
−
1
of the ferrocenyl group at 3097 and 489 cm due to ν(C H)
and ν (Fe-Cp) vibrations, respectively, which can be found in
Thermogravimetric Analysis (TGA)
The TG-DSC measurements of complex 1 were determined
−
1
the compound (3092 and 482 cm ). The bands attributable to
◦
in the range of 20–650 C in air. TG data (Figure 5) shows that
−
1
H2O occur at position of 3431 cm . The strong absorption
◦
complex 1 is stable up to 67.4 C, then firstly loses weight from
7.4 to 130 C corresponding to losses of the uncoordinated
−
1
−
bands at 1612 and 1505 cm are assigned to νas(COO ) and
◦
6
−
νs(COO ) vibrations, respectively, and the vibrational bands
around 1308 and 1104 cm can be attributed to the δ(CH3) and
water molecules, secondly goes through complicated multiple
−
1
◦
weight loss steps in the temperature range of 130–500 C cor-
[22]
ρ(CH3), respectively.
The characteristic absorption of phen
responding to the decomposition of phen and the organic units
are observed as four strong or medium bands in 1533, 848, 776
of ferrocenyl ligand. Finally, a plateau region is observed from
−
1
and 730 cm . In conclusion, these IR data are consistent with
◦
5
(
00 to 650 C. A dark-brown amorphous residue of FeO+ CuO
the crystal data of the compound 1.
observed 25.16%, calculated 25.51%) remained. There is one
very strong exothermic peak (395.6 C) on the DSC curve of 1.
◦
Electrochemical Studies of Complex 1
As can be see from Figure 4, both the complex and corre-
sponding ferrocenyl ligand exhibit a quasi-reversible oxidation- Supplementary Material
reduction process, which can be assigned to the oxidation of the
Crystallographic data for the structural analysis has been
ferrocene unit. The oxidation and reduction peaks of the ligand deposited with the Cambridge Crystallographic Data Centre,
3
-carboxymethylamino-1-ferrocenyl-2-buten-1-one are 0.803 CCDC No. 693234. Copies of this information may be obtained
V and 0.752 V, respectively, and the electric potential difference free of charge from The Director, CCDC, 12 Union Road, Cam-
of both peaks is 0.051 V. Oxidation and reduction peaks of the bridge, CB2 1EZ, UK (fax: + 44-1223-336033; E-mail: de-
complex are 0.611 V and 0.545 V, respectively, and the electric posit@ccdc.cam.ac.uk or kwww:http://www.ccdc.cam.ac.ukl).

4
94
L. H. YAN ET AL.
12. Dario, B., Stefano, L. G., Fabrizia, G., Giuseppe, P., and Marco, P.
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Illustrations
3
Synthesis, structure and prop- One novel complex [Cu(η -FcC(O)CH C(CH3)NCH2COO)(phen)]· 1.5H2O has been prepared
erties of a novel Cu(II) com- and structurally characterized. There are three kinds of components in the complex, copper ions,
plex constructed from de- ferrocenyl enaminone-based carboxylate units and 1,10-phenantholine. The molecular structure of
signed ferrocenyl ligand
the complex has been characterized by elemental analysis, IR and single crystal X-ray diffraction.
Its thermal and electrochemical properties are presented.