1D Nickel Coordination Polymers with an Unnatural Amino Acid Prepared by in situ Double Michael Addition of Ethylenediamine to (E,E)-Muconic Acid

Full text of DOI:10.1002/bkcs.11311

Note
DOI: 10.1002/bkcs.11311
BULLETIN OF THE
J. Do et al.
KOREAN CHEMICAL SOCIETY
1
D Nickel Coordination Polymers with an Unnatural Amino Acid
Prepared by in situ Double Michael Addition of Ethylenediamine
to (E,E)-Muconic Acid
†,*
†
†
†
‡,*
Junghwan Do, Jaeun Kang, Yeonsun Jung, Yong Sun Park, and Allan J. Jacobson
†Department of Chemistry, Konkuk University, Seoul 143-701, Republic of Korea.
*
E-mail: junghwan@konkuk.ac.kr
Department of Chemistry and Texas Center for Superconductivity, University of Houston, Houston, TX,
7204-5003, USA. *E-mail: ajjacob@uh.edu
‡
7
Received July 25, 2017, Accepted September 26, 2017
Keywords: Ni coordination polymer, Michael reaction, Muconic acid, Ethylenediamine, Piperazine-2,
3
-diacetic acid
In general, the topology of coordination polymers can be
designed by controlling the size, shape, and charge of the
combination of various organic linkers and/or inorganic
metal connectors. Amino acids are well-known organic
linkers for readily forming coordination polymers with
However, few examples are currently known for the two
consecutive Michael reactions of the derivatives of muconic
acid, a dicarboxylic acid containing a conjugated di-ene
group. Only one example was reported in detail of the 1,4-
addition of muconaldehyde with two thiols to afford bis-
1
–4
20
metal connectors.
The naturally occurring amino acids
Michael adducts.
acting as metal connectors, however, are limited in number.
Among the known 20 proteinogenic amino acids, only
aspartic acid and glutamic acid comprise dicarboxylic
groups that are needed for constructing rigid polymeric
We herein expand the scope of this one-step crystal engi-
neering strategy by introducing (E,E)-muconic acid, a dicar-
boxylic acid containing a conjugated di-ene group. The
Lewis acidic properties of nickel cation promotes the
Michael reactions of the nickel complex of (E,E)-muconic
acid with amines. Surprisingly, this has resulted in isolation
of a new 1D coordination polymer, Ni(piperazine-2,3-diace-
tate)(H O) , which is the first example formed in situ by
5–9
metal–amino acid structures. Thus, the synthesis of new
amino acids including dicarboxylic groups is of great
importance in constructing new polymeric structures. In
general, for the synthesis of amino acids, the Michael addi-
tion or Mannich reaction typically has been used to form
C─N bonds by simple addition of amines to C=C double
2
2
double Michael reactions of (E,E)-muconic acid with ethy-
lenediamine to afford tailor-made β-amino acid, piperazine-
2,3-diacetic acid. The heterocyclic product in Ni(piperazine-
10–13
bonds.
We have recently demonstrated a one-step crystal engi-
neering strategy for the formation of several “unnatural”,
tailor-made α-amino acid–metal complexes containing race-
mic mixtures of the chiral ligands, piperazinyl succinic
acid, N-benzyl aspartic acid, N-aminoethyl aspartic acid,
and N-aminopropyl aspartic acid which are formed under
mild hydrothermal conditions in situ by Michael addition
of piperazine, benzylamine, ethylenediamine, and 1,3-
2,3-diacetate)(H O)2 is formed by the Michael addition
2
reaction of an amine group of ethylenediamine followed by
intramolecular Michael reaction with the other amine group.
In addition, demetallation of the resulting functionalized
piperazine to the corresponding amino acid can be achieved
by acidic hydrolysis. The nickel complex has been demetal-
lated in boiling HCl to yield a single diastereomer of 2,3-
piperazinediacetic acid and following esterification of the
diacetic acid afforded dimethyl 2,3-piperazinediacetate.
The hydrothermal reaction of nickel chloride hexahy-
1
4–16
diaminopropane to fumaric acid, respectively.
This
type of Michael reaction, i.e., the direct amination of
α,β-unsaturated dicarboxylic acid is rarely reported,
although the direct amination of α,β-unsaturated monocar-
boxylic acid can readily be effected, and several synthetic
methods for amination of α,β-unsaturated dicarboxylic acid
derivatives, such as mono- or diester and monoamide, are
drate, (E,E)-muconic acid, and ethylenediamine in H O at
2
ꢀ
160 C produced blue polyhedral crystals of Ni(piperazine-
2,3-diacetate)(H O) 1. The structure of 1 was determined
2
2
by single crystal X-ray diffraction. Elemental analysis and
a comparison of the X-ray powder pattern with one simu-
lated from the single crystal data (Figure S1, Supporting
information) confirm the homogeneity and purity of the
bulk product.
17
well known.
In general, the Michael reaction, that is the regioselective
1,4-addition of nucleophiles to activated olefins, is one of
the versatile methods used for C─C, C─N bond formation,
and has found wide application in organic synthesis.
The product crystallizes in the monoclinic space group
C2/c with four formula units per unit cell. Crystallographic
18,19
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data for 1 are summarized in Table 1. The piperazine-2,3-
diacetate anion positioned on two-fold rotational axis sym-
metry is a diastereomer containing two chiral carbon atoms,
C4. Two carbon atoms, C2 and C3 bonded to the chiral
carbon atoms (C4) are disordered over two positions with
~2
and C3 have four possible configurations, (2R, 3S), (2S,
R), (2R, 3R), and (2S, 3S); however, considering unequal
3
and 1
/3
occupancy ratios, respectively. Therefore, C2
3
number of occupancy factors of C2 and C3, the ordered
piperazine-2,3-diacetate anion should be either C2–C4–
C4’–C2’ (2R, 3R) or C3–C4–C4’–C3’ (2S, 3S), a trans
configuration, not C2–C4–C4’–C3’(2R, 3S) or (2S, 3R), a
cis configuration. Lower-symmetric space groups, C2 and
Cc of C2/c were checked, but the disordering behavior of
the piperazine-2,3-diacetate anion was not resolved.
Figure 1. Displacement ellipsoids of the local structure 1 drawn at
50% probability level. Nickel, carbon, oxygen, and nitrogen atoms
are purple, gray, red, and blue ellipses, respectively. Hydrogen
atoms are represented by white spheres.
One crystallographically distinct nickel atom located on
the center of inversion (¼, ¼, ¼) is coordinated by two
nitrogen atoms and two oxygen atoms from two piperazine-
The Ni(rac-piperazine-2,3-diacetate)(H O)2 chains are
2
further stabilized by the presence of hydrogen bonds
between the coordinated water molecules and the carboxyl-
ate oxygen atoms in a complex arrangement, with the dis-
2,3-diacetate anions in square planar coordination with the
Ni─O and Ni─N distances of 2.030(2) and 2.114(2) Å,
respectively. Two additional water molecules in a trans
configuration complete a distorted octahedron with the dis-
tance of 2.125(2) Å, Figure 1. The NiO N (H O) octahe-
tance of d(Ow1•••O2) = 2.790(3), 3.035(3)
Å
and
d(Ow1•••O1) = 2.879(2), 2.997(3), and 3.030(3) Å within
<3.5 Å, which result in the formation of a framework,
Figure 3.
The FT-IR spectra exhibits the characteristic absorption
bands of the carboxylic unit in the piperazine-2,3-diacetate
2
2
ꢀ
2
2
dron is slightly distorted from regular 90 angles (87.69
ꢀ
(
7)–92.31(7) ). In the piperazine-2,3-diacetate anion, two
nitrogen and two oxygen atoms (O1) are coordinated to
nickel atoms, and two remaining oxygen atoms (O2) in car-
boxylate groups are terminal. The one unique piperazine-
ligand: 1671 m, 1572s, (νas CO ), 1458 m, 1408s, (νs
2
−
1
CO ), and 913w, 849w cm (δ CO ). The peak near
2
2
−
1
3404 s(br) cm confirms the presence of H O groups. The
2
−
1
2,3-diacetate acting as tetradentate ligand, bridges two
peaks at 3191 m–2889 w, and 1330 w–956 w cm are
attributed from the C─N, C─C, O─H, N─H and C─H
vibration frequencies (Figure S2).
nickel atoms forming infinite zigzag neutral chains,
Ni(piperazine-2,3-diacetate)(H O) along the [101] direc-
2
2
tion (Figure 2).
Compound 1 remains stable upon heating in N up to
2
ꢀ
~
200 C. On further heating, a weight loss of 12.63%
ꢀ
Table 1. Crystallographic details for 1.
occurs below 300 C, which corresponds to the loss of two
ꢀ
water molecules (calcd 12.21%). Above 300 C, the mate-
rial starts decomposing in several steps up to ~500
Formula
8 16 2 6
C H N NiO
ꢀ
C
Formula weight
T (K)
Crystal size (mm)
Crystal system
Space group
a (Å)
294.94
296 (2)
0.22 × 0.18 × 0.16
Monoclinic
C2/c
attributable to the loss of piperazine-2,3-diacetate mole-
ꢀ
cules. Assuming that the residue at 800 C corresponds to
NiO, the overall observed weight loss (75.99%) is in good
agreement with the calculated value (74.68%) for formation
of NiO (Figure 4). The final products after heat treatment
were confirmed by powder X-ray diffraction to be NiO
15.141 (3)
7.3287 (15)
10.769 (2)
116.41 (3)
1070.2 (4)
4
b (Å)
(
Figure S3).
c (Å)
In conclusion, the racemic piperazine-2,3-diacetate
ligand is formed under mild hydrothermal conditions in situ
ꢀ
β ( )
V (Å )
3
Z
3
Calculated density (g/cm )
Absorption coefficient (mm )
F(000)
1.830
1.834
616
−
1
Independent reflections
GOF on F
969
0.971
2
R indices [I > 2σ(I)]
R
R
1
1
= 0.0276, wR
= 0.0422, wR
2
= 0.0687
= 0.0722
Figure 2. View of the chain in 1. Purple circles and polyhedral
represent Ni atoms, and the other labeling scheme is the same as
that in Figure 1.
R indices (all data)
2
3
(Δρ) max:min (e/Å )
0.366, −0.173
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Michael addition of amine to dicarboxylic acid group con-
taining di-enes as well as mono-enes warrants more system-
atic investigation. Moreover, successful releasing trans-2,3-
piperazinediacetic acid from the nickel complex 1 by acidic
hydrolysis may suggest an effective approach to synthesize
new nonproteinogenic amino acids that detours complicated
organic reaction procedures.
Experimental
All chemicals were of reagent grade and used as received
from commercial sources without further purification. Pow-
der X-ray diffraction analyses were performed using a
Rigaku Ultima IV diffractometer (Cu Kα radiation)
(
Rigaku, Tokyo, Japan). Thermal analyses were carried out
ꢀ
in N at a heating rate of 5 C/min, using a high-resolution
2
Perkin-Elmer TGA7 Thermal Analyzer (Waltham, MA,
USA). Infrared spectra were recorded on a Nicolet 6700
FT-IR spectrometer (Waltham, MA, USA) within a range
−
1
of 400–4000 cm using the KBr pellet method. Galbraith
Laboratories, Inc., (Tennessee, USA) performed the ele-
1
13
Figure 3. Layer formation of 1 by strong hydrogen bonding
within <2.9 Å (dotted red lines) between the chains viewed paral-
lel to [101]. Labeling scheme is the same as that in Figure 2.
ment analyses. The H and C nuclear magnetic resonance
(NMR) spectroscopic data were recorded with a Bruker
1
13
(400 MHz for H NMR, 100.6 MHz for C NMR) spec-
trometer (Billerica, MA, USA). Chemical shifts (δ) are
1
reported in ppm relative to CDCl (δ = 7.26 ppm for H
3
13
100
NMR, δ = 77.07 ppm for C NMR). Multiplicities are
reported as s (singlet), d (doublet), t (triplet), q(quartet),
and br. (broad signal). Coupling constants (J) are reported
in Hz. HRMS spectra were recorded with a JEOL JMS-700
8
6
4
2
0
0
0
0
(
Akishima, Tokyo, Japan) by using the FAB method.
Synthesis of Ni(Piperazine-2,3-Diacetate)(H O)2 (1).
2
The product was synthesized from a mixture of nickel chlo-
ride hexahydrate (0.071 g, 0.3 mmol), (E,E)-muconic acid
(0.132 g,
0.9 mmol),
ethylenediamine
(0.02 mL,
0
.9 mmol), and distilled water (1.0 mL), which was sealed
ꢀ
in a Pyrex tube and heated to 160 C for 64 h, followed by
cooling to room temperature at 20 C/h. The solution pH
ꢀ
100
200
300
400
500
600
700
800
values before and after the reaction were ~5 and ~6, respec-
tively. The product was filtered, and blue polyhedral crys-
tals with unidentified yellow powder were found. The yield
of the product was ~40%, based on nickel. The product is
stable in air and water, and is insoluble in common solvents
such as ethanol, DMF, acetone, and THF. EDS analysis
confirmed the presence of Ni. The element analyses gave
the following results: obsd. (wt %) (C, 32.73; N, 9.68; H,
5.61), calcd (wt %) (C, 32.60; N, 9.50; H, 5.43). IR (KBr):
3404 s(br), 3191 m, 2960 w, 2889 w, 1671 m, 1572 s,
1458 m, 1408 s, 1330 w, 1293 w, 1169 m, 1137 w,
1116 w, 1056 w, 998 w, 956 w, 913 w, 849 w, 795 m,
757 m, 689 m, 629 w, 513 w cm . A comparative synthe-
sis without nickel chloride was performed to check the
effect of metal salt on the occurrence of the Michael reac-
tion, and the residual solution does not contain the
piperazine-2,3-diacetate ligand as proved by NMR.
o
Temperature ( C)
Figure 4. TGA curve of 1.
by double Michael additions of ethylenediamine to (E,E)-
muconic acid. Previously, we have reported several metal
complexes of which the ligands were obtained from the
Michael addition of amines to fumaric acid (mono-ene) that
possess divalent anions or monovalent anion forming some-
times a zwitterion depending on the amine species and
1
5,16
coordination behavior of the terminal nitrogen atoms.
−1
The successful synthesis of 1 utilizing the direct amination
of α,β-unsaturated dicarboxylic acid is not only limited to a
mono-ene but also can be extended to di-enes such as a
E,E)-muconic acid. The charge versatility and coordination
behavior of nonproteinogenic amino acids prepared by
(
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BULLETIN OF THE
Note
KOREAN CHEMICAL SOCIETY
13
and
C
NMR of dimethyl 2,3-piperazinediacetate
X-Ray Crystallography. Single-crystal X-ray analysis
(
Figures S4 and S5), and HRMS of dimethyl 2,3-
was performed on a Siemens SMART platform diffractom-
eter outfitted with an Apex II area detector and monochro-
matized graphite Mo Kα radiation. The structure was
piperazinediacetate information (Figure S6).
2
solved by direct methods and refined on F by full-matrix
2
1
References
least-squares using SHELXTL. The hydrogen atoms in
the water molecule were located in difference Fourier maps.
Other hydrogen atoms in the piperazine-2,3-diacetate ligand
except for the C4 carbon atom connected to disordered car-
bon atoms (C2, C3) were generated geometrically and
allowed to ride on their respective parent atoms. All non-
hydrogen atoms were refined anisotropically. Crystallo-
graphic data for the structures reported here has been
deposited with CCDC (Deposition No. CCDC-1516055 for
1
2
3
. T. Kundu, S. C. Sahoo, R. Banerjee, CrystEngComm 2013,
1
5, 9634.
. D. Sarma, K. V. Ramanujachary, S. E. Lofland,
T. Magdaleno, S. Natarajan, Inorg. Chem. 2009, 48, 11660.
. R. Ganguly, B. Sreenivasulu, J. J. Vittal, Coord. Chem. Rev.
2008, 525, 1027.
4. H.-Y. An, E.-B. Wang, D.-R. Xiao, Y.-G. Li, Z.-M. Su,
L. Xu, Angew. Chem. 2006, 118, 918.
5
6
7
8
. L. Antolini, L. Menabue, G. C. Pellacani, G. Marcotrigiano,
Dalton Trans. 1982, 2541.
. E. V. Anokhina, A. J. Jacobson, J. Am. Chem. Soc. 2004,
1
). These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html or from CCDC,
2 Union Road, Cambridge CB2 1EZ, UK, E-mail:
deposit@ccdc.cam.ac.uk.
Isolation of the
Piperazinediacetate by Demetallation of Ni(Piperazine-
1
1
26, 3044.
. E. V. Anokhina, Y. B. Go, Y. Lee, T. Vogt, A. J. Jacobson,
J. Am. Chem. Soc. 2006, 128, 9957.
. Y. Zhang, M. K. Saha, I. Bernal, CrystEngComm 2003, 5, 34.
Ligand,
Dimethyl
2,3-
2
1
,3-Diacetate)(H O) (1).
A solution of complex
2
2
9. M. Mizutani, N. Maejima, K. Jitsukawa, H. Masuda,
H. Einaga, Inorg. Chim. Acta 1998, 283, 105.
(100 mg) in 2.0 M-HCl aqueous solution (10 mL) was
ꢀ
heated at 80 C for 1 h and then water was removed under
reduced pressure. The residue was dissolved in 10 mL of
10. X. Li, X.–. S. Xue, C. Liu, B. Wang, B.–. X. Tan, J.–. L. Jin,
Y.–. Y. Zhang, N. Dong, J.–. P. Cheng, Org. Biomol. Chem.
2012, 10, 413.
ꢀ
methanol and treated with 3 mL of acetyl chloride at 0 C.
1
1
1
1
1. Z.–. W. Ma, Y.–. X. Liu, P.–. L. Li, H. Ren, Y. Zhu,
J.–. C. Tao, Tetrahedron Asymmetry 2011, 22, 1740.
2. T. Miura, A. Masuda, M. Ina, K. Nakashima, S. Nishida,
N. Tada, A. Itoh, Tetrahedron Asymmetry 2011, 22, 1605.
3. X. Z. Liang, N. N. Quan, J. Wang, J. G. Yang, Sci. China,
Ser. B: Chem. 2009, 52, 874.
The mixture was stirred at room temperature for 1 h and
then poured into a saturated NaHCO solution. After the
3
aqueous layer was thoroughly extracted with methylene
chloride, the extracts were dried over anhydrous sodium
sulfate, filtered, evaporated to give 29 mg of product as
1
pale yellow oil in 38% yield. H NMR (CDCl 400 MHz)
3
,
4. For
a definition of “tailor-made amino acids”, see:
3
.70 (s, 6H, OCH ), 3.55–3.40 (m, 2H, NCH), 3.02–2.87
3
V. A. Soloshonok, C. Cai, V. J. Hruby, L. Van Meervelt, Tet-
rahedron 1999, 55, 12045.
(
m, 4H, NHCH ), 2.67–2.56 (m, 2H, CH CO ), 2.44–2.39
2 2 2
1
3
(m, 2H, CH CO ); C NMR (CDCl3, 100 MHz) 172.1
15. J. Do, Y. Lee, J. Kang, Y. S. Park, B. Lorenz, A. J. Jacobson,
Inorg. Chem. 2012, 51, 3533.
16. J. Do, J. Kang, Y. Lee, K. M. Ok, A. J. Jacobson, Inorg.
Chim. Acta 2015, 430, 280.
2
2
(
(
CO ), 56.1 (NCH), 51.9 (OCH ), 45.8 (NCH ), 36.9
2 3 2
+
CH CO ); HRMS: calcd. For C H N O [M + 1]
2
2
10 19 2 4
231.1345; found 231.1351.
1
1
1
2
7. P. S. Piispanen, P. M. Pihko, Tetrahedron Lett. 2005, 46,
751 and references therein.
8. A. G. Csaky, G. de la Herran, M. C. Murcia, Chem. Soc. Rev.
010, 39, 4080.
9. D. Enders, C. Wang, J. X. Liebich, Chem. Eur. J. 2009, 15,
1058.
0. A. P. Henderson, C. Bleasdale, K. Delaney, A. B. Lindstrom,
S. M. Rappaport, S. Waidyanatha, W. P. Watson,
B. T. Golding, Bioorg. Chem. 2005, 33, 363.
Acknowledgments. This work was supported by the
2
National Research Foundation of Korea Grant funded by
the Korean Government (NRF–2012R1A1A2005118). AJJ
thanks the R.A. Welch Foundation (Grant #E–0024) for
support of his work.
2
1
Supporting Information. Experimental powder X-ray
data and simulated powder X-ray patterns of 1 (Figure S1),
FT-IR (Figure S2), Powder X-ray data after TGA and simu-
1
lated powder X-ray patterns of NiO (Figure S3), H NMR
21. G. M. Sheldrick, Acta Crystallogr. Sect. A 2008, 64, 112.
Bull. Korean Chem. Soc. 2017
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