Syntheses and crystal structures of a novel 20-membered N3O2-donor macrocycle and its disilver(I) bis(macrocycle) and monocadmium(II) complexes

Full text of DOI:10.1002/bkcs.10533

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DOI: 10.1002/bkcs.10533
BULLETIN OF THE
D. H. Kang and K. S. Choi
KOREAN CHEMICAL SOCIETY
Syntheses and Crystal Structures of a Novel 20-Membered N3O2-Donor
Macrocycle and Its Disilver(I) Bis(Macrocycle) and Monocadmium(II)
Complexes
*
Dong Hee Kang and Kyu Seong Choi
Department of Chemistry Education, Kyungnam University, Changwon 631-701, South Korea.
*E-mail: kschoi@kyungnam.ac.kr
Received March 10, 2015, Accepted July 15, 2015, Published online September 30, 2015
Keywords: Macrocycle, Complex, Cadmium, Silver, X-ray crystal structure
In macrocyclic coordination chemistry, the cation to cavity
diethylenetriamine in methanol followed by sodium borohy-
dride reduction. The 1H and 13C NMR spectra together with
elemental analysis andmassspectrawereall inagreementwith
the proposed structure.
size ratio is an important parameter for understanding
complexation-based metal ion recognition.1 For example,
16- to 19-membered ring ligands incorporating dibenzo sub-
unitshavebeenwidelyinvestigatedbecausetheseligandsgen-
erally favor stable 1:1 complexation and show intermediate
flexibility which limits the number of observed complex
conformations.1,2
Following these earlier studies, new synthetic results and
applications for the related macrocyclic systems have contin-
ued up to the present.3 In terms of macrocyclic cavity sizes,
macrocyclic rings greater than 24-membered are strong candi-
dates for forming dinuclear complexes in both the synthetic
and bioinorganicchemistryareas.4 However, their preparation
and purification tend to be difficult, often leading to the forma-
tion of the target ring in low yield.
On the other hand, the preparation and structural character-
ization of the complexes with 20- to 23-membered macro-
cycles have been less investigated because their cavity sizes
are too large for planar complexation with one metal ion but
too small for coordination with two metal ions simultane-
ously.5 However, macrocycles with the 20–23 membered
rings are expected togive the unusual coordination topologies,
while another advantage is that the latter category is usually
relatively easier to prepare than larger analogs. Recently, sev-
eral kinds of 20- to 23-membered oxathia-tribenzo macro-
cycles and their discrete and polymeric complexes showing
less common stoichiometric ratios have been reported.5 To
the best of our knowledge, such 20-membered O2N3-donor
analogs have not been reported so far.
In this work, we present a 20-membered O2N3-macrocycle
L incorporating a tribenzo-subunit (Scheme 1); L is a poten-
tially pentadentate macrocyclic ligand which is expected to
react with a wide range of metal species. In particular, d10
metal ions are free from formation of specific coordination
geometries and often show favorable reactivity toward poly-
oxaaza ligand systems. Here we report the synthesis of
L along with an X-ray study of its complexes incorporating
the d10-metal ions Cd(II) and Ag(I).
Scheme 1. Synthesis of L.
Reaction of L with Cd(NO3)2Á4H2O in dichloromethane/
methanol afforded a colorless crystalline product 1 suitable
forX-rayanalysis(Table 1). Thecrystal structure of 1isshown
in Figure 1 and its selected geometric parameters are presented
in Table 2. The crystal structure of 1 has an anion-coordinated
mononuclear arrangement with the formula being [Cd(L)
(NO3)2]. Unlike our expectation, the Cd(II) center locates out-
side the macrocyclic cavity (Figure 1(a)). The Cd(II) center is
in a hexa-coordinated environment, being bound to the three
consecutive N atoms from L in a bent arrangement (Figure 1
(b)). The coordination environment is completed by three O
atoms arising from monodentate and bidentate nitrate ions,
with bond lengths [Cd1 O3 2.445(10), Cd1 O4 2.382(8),
Cd1 O6 2.331(7) Å] that fall within the range observed for
other nitrato complexes of Cd(II).7 The Cd N bond lengths
[Cd1 N1 2.312(9), Cd1 N2 2.332(7), Cd1 N3 2.373(9)
Å] are also within the normal literature range for this bond
type.8 Two O donors of L remain uncoordinated. As shown
in Figure 1(c), the resulting geometry of the
Cd(II) coordination sphere in 1 can be described as a distorted
trigonal prism.9 Thetwotrigonalfacesofthetrigonal prism are
defined by O3 O4 O6 and N1 N2 N3.
The preference for the observed anion-coordinated mono-
nuclear complex formation in which the metal center locates
outside the macrocyclic cavity could be associated with the
stronger affinity of the charged nitrateO atoms over the neutral
O donors in the macrocycle toward Cd(II). In addition, the rel-
atively larger cavity size of L compared with the Cd(II) ion
The novel tribenzo-O2N3-macrocycle L was obtained
directly in 75% yield from reaction of dialdehyde6 with
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radius is expected to lower the coordination affinity of the
macrocycle for this ion.
When AgPF6 was used in the reaction with L under similar
conditions, a colorless crystalline product 2 suitable for X-ray
analysis was isolated (Table 1). Interestingly, the crystal
structure shows that 2, [Ag2(L)2](PF6)2, is a dinuclear
bis(macrocycle) complex with a 2:2 (metal-to-ligand) stoichi-
ometry as shown in Figure 2. Selected geometric parameters
are presented in Table 3. Unlike 1, no anions are included in
the coordination sphere in 2. Since the structure shown in
Figure 2(a) is generated through an inversion symmetry, the
Table 1. Crystal and experimental data for 1 and 2.
Table 2. Selected bond length [Å] and bond angles [ꢀ] for 1, [Cd
(L)(NO3)2].
1
2
Formula
Temperature (K)
Formula weight
Crystal system
Space group
a (Å)
b (Å)
c (Å)
α (deg)
β (deg)
C26H31CdN5O8
173(2)
653.96
Triclinic
P−1
10.99(5)
11.07(4)
12.09(5)
72.37(7)
84.78(4)
73.63(7)
1345(9)
2
C26H31AgF6N3O2P
173(2)
670.38
Triclinic
P−1
9.3365(2)
12.0608(2)
12.4584(2)
79.8460(10)
89.3030(10)
83.9960(10)
1373.31(4)
2
Cd1 N1
Cd1 N3
Cd1 O4
2.312(9)
2.373(9)
2.382(8)
162.56(12)
94.5(3)
Cd1 N2
Cd1 O3
Cd1 O6
N2 Cd1 O3
N2 Cd1 N3
N1 Cd1 N3
N1 Cd1 O6
N3 Cd1 O3
O6 Cd1 N3
O6 Cd1 O3
2.332(7)
2.445(10)
2.331(7)
143.97(12)
77.4(3)
98.57(12)
146.89(16)
137.8(2)
111.39(15)
80.25(19)
N2 Cd1 O4
N2 Cd1 O6
N1 Cd1 N2
N1 Cd1 O3
N1 Cd1 O4
N3 Cd1 O4
O6 Cd1 O4
O4 Cd1 O3
78.1(2)
87.05(17)
101.5(3)
85.5(2)
94.8(3)
52.58(13)
γ (deg)
V (Å3)
Z
Dcalc(g/cm3)
1.615
0.871
1.621
0.862
(a)
μ (mm−1
)
2θmax (deg)
56.00
56.00
Reflections collected
No. of reflection used
[>2σ(I)]
24 778
24 741
6482 (Rint
0.0512)
1.049
0.0459, 0.1154
0.0559, 0.1212
=
6604 (Rint
0.0278)
1.029
0.0308, 0.0766
0.0374, 0.0810
=
Goodness-of-fit on F2
R1, wR2 [I> 2σ(I)]
R1, wR2 (all data)
(b)
(a)
(b)
Figure2. Crystal structure of thedisilver(I) bis(macrocycle) complex
2, [Ag2(L)2](PF6)2:(a)front viewand(b) sideview. Noncoordinating
anions are omitted.
(c)
Table 3. Selected bond length [Å] and bond angles [ꢀ] for 2,
[Ag2(L)2](PF6)2].
Ag1 N1
Ag1 N3A
2.2268(17) Ag1 N2A
2.2951(18) Ag1 O2A
2.3765(17)
2.8324(16)
Figure 1. Crystal structure of the mononuclear cadmium(II) complex
1, [Cd(L)(NO3)2]: (a) front view, (b) side view, and (c) coordination
environment of the cadmium(II) in 1 showing the distorted trigonal
prismatic arrangement.
N1 Ag1 N3A 154.04(6)
N3A Ag1 N2A 77.96(6)
N3A Ag1 O2A 76.63(6)
N1 Ag1 N2A 121.71(6)
N1 Ag1 O2A 110.36(6)
N2A Ag1 O2A 104.81(6)
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asymmetric unit in the complex part contains one L and
one Ag(I).
Synthesis of L. Dialdehyde6 (3.01 g, 8.66 mmol) prepared
from the reaction of salicylaldehyde and 1,3-bis(bromo-
methyl)benzene was dissolved in methanol and slowly added
to diethylenetriamine (1.59 g, 15.4 mmol) in methanol (50
mL). The reaction mixture was refluxed, and then sodium bor-
ohydride (0.984 g, 25.9 mmol) with small amount of borax
was slowly added to the stirred solution. The reaction mixture
was rapidly stirred for a further 6 h, allowed to cool to room
temperature, and then filtered. Water was added, and the mix-
ture was extracted with CH2Cl2. Removing the CH2Cl2 under
avacuumgaverisetocrude oil. Treatment ofthe crude product
on a silica gel column eluted with MeOH CH2Cl2 (20:80 v/v)
gave pure product L as a pale yellow glassy solid (yield 1.93 g,
In 2, the complex cation consists of a dimeric arrangement
in which two macrocycles in a twist and bent arrangement
sandwich two Ag(I) ions. Due to this sandwich structure,
the Ag(I) ions are shielded by the macrocycles from further
interaction with solvent or anions (Figure 2(b)). Each
Ag(I) center is four-coordinate, being bound to an O and
two N donors from one L. The coordination sphere is com-
pleted by an N donor from another L. The Ag N bond lengths
[Ag1 N1 2.2268(17), Ag1 N2A 2.3765(17), Ag1 N3A
2.2951(18) Å] are typical for such bonds10 and the Ag O
bond [2.8324(16) Å] falls at the longer end in the correspond-
ing values (2.4 2.9 Å) for related systems.11
1
75%). Mp: 78–80 ꢀC. H NMR (300 MHz, CDCl3): δ =
The tetrahedral bond angles around the Ag atom vary from
76.6(6)ꢀ (N3A Ag1 O2A) to 154.0(6)ꢀ (N1 Ag1 N3A).
The observed large deviations from regular tetrahedral geom-
etry are due to the formation of the hexagonal metallacycle as
well as the steric hindrance between two adjacent macro-
cycles. The separation between the two Ag atoms
(Ag1ÁÁÁAg1A, 5.65 Å) is far outside the range expected for
an agentophilic interaction.12 The preferred formation of the
dinuclear bis(macrocycle) complex appears mainly associated
with the lower coordination affinity of the anion. It was not
possible for us to prepare the corresponding AgNO3 complex
with L.
In summary, a 20-membered O2N3-macrocycle L was
synthesized in a reasonable yield via a cyclization reaction
between dialdehyde and diethylenetriamine followed by
reduction. Reaction of L with cadmium(II) nitrate yielded a
1:1 complex, in which the cadmium(II) locates outside the
cavity assigned to the strong anion coordination and the larger
cavitysizeofthemacrocyclecomparedwiththemetalionsize.
From the reaction of L with silver(I) hexafluorophosphate, a
disilver(I) bis(macrocycle) complex without anion coordina-
tion was isolated. In both cases, all nitrogen donors are coor-
dinated to the metal center, but depending on the anion
coordination ability, the coordination behaviors of the cations
afford different stoichiometric complexes. Further work on a
wider range of metal complexes of L is in progress in our
laboratory.
7.76–6.95 (m, 12H, aromatic), 5.12 (s, 4H, ArCH2O), 3.85
(s, 4H, ArCH2NH), 2.68 (s, 8H, HNCH2CH2NH). 13C
NMR (75 MHz, CDCl3): δ = 155.9, 136.4, 130.0, 128.2,
127.7, 127.3, 126.5, 125.6, 120.2, 110.9, 69.2, 46.8, 45.6,
45.3. IR (KBr pellet): 3062 (w), 3036 (w), 2941 (m), 2808
(m), 1664 (m), 1599 (s), 1494 (s), 1453 (s), 1378 (m), 1291
(w), 1237 (s), 1161 (w), 1113 (m), 1045 (m), 1009 (m),
845 (w), 756 (s), 698 (m) cm−1. Anal. Calcd for
[C26H31N3O2]: C, 74.79; H, 7.48; N, 10.06. Found: C,
74.72; H, 5.94; N, 10.08%. Mass (ESI) spectrum m/z:
418.42 (L)+.
Preparation of 1, [Cd(L)(NO3)2]. Cd(NO3)2Á4H2O (48.0
mg, 0.156 mmol) in dichloromethane was added to a solution
of (60.2 mg, 0.144 mmol) in methanol. Slow evaporation of
the solution at room temperature afforded a colorless crystal-
line product 1 suitable for X-ray analysis. Mp: 230–232 ꢀC
(decomp.). IR (KBr pellet): 3064 (w), 2926 (m), 2871 (m),
−
1598 (m), 1495 (m), 1452 (m), 1384 (s, NO3 ), 1293 (m),
1238 (m), 1089 (w), 1022 (m), 901 (m), 840 (m), 758 (s),
692 (w) cm−1. Anal. Calcd for [C26H31CdN5O8]: C,
47.75; H, 4.78; N, 10.71. Found: C, 47.63; H, 4.85; N,
10.43%. Mass (ESI) spectrum m/z: 593.17 [Cd(L)NO3]+.
Preparation of 2, [Ag2(L)2](PF6)2]. AgPF6 (33.6 mg, 0.133
mmol) in dichloromethane was added to a solution of
L (45.4 mg, 0.101 mmol) in methanol. Slow evaporation of
the solution afforded a colorless crystalline product 2 suitable
for X-ray analysis. Bulk purity of 2 was confirmed by its
PXRD patterns. Mp: 185–187 ꢀC (decomp.). IR (KBr pellet):
2930 (m), 2861 (m), 1602 (m), 1494 (m), 1455 (m), 1380 (w),
1238 (m), 1173 (m), 1118 (m), 1008 (m), 913 (m), 841 (s,
Experimental
PF6 ), 759 (m), 672 (m) cm−1. Mass (ESI) spectrum m/z:
−
General. All chemicals were purchased from commercial
sources andusedasreceived. Allsolventsusedwereofreagent
grade. Elemental analyses werecarried outon a LECO CHNS-
932 elemental analyzer (LECO Corporation, St. Joseph, MI,
USA). Electrospray ionization-mass (ESI-MS) spectra were
recorded in positive ion mode from acetonitrile solution with
Thermo Scientific LCQ Fleet spectrometer (Thermo Scien-
tific, Waltham, MA, USA). The Fourier transform infrared
spectroscopy (FT-IR) spectra were recorded using Thermo
Fisher Scientific Nicolet iS 10 FT-IR spectrometer
(Madison, WI, USA) with KBr pellets.
524.33 [Ag(L)]+.
X-ray Crystallographic Analysis. Single crystals suitable
for data collection were chosen under an optical microscope,
mounted on glass fiber, and frozen under a stream of cryogenic
nitrogen gas before data collection. Intensity data were col-
lected on a Bruker SMART APEX II ULTRA diffractometer
(Bruker, Billerica, MA, USA) attached with a CCD detector
and graphite-monochromated Mo Kα (λ = 0.71073 Å) radia-
tion. Data collection, data reduction, and semi-empirical
absorption correction were carried out using the software
package of APEX2.13 All of the calculations for the structure
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6. (a) K. M. Atkinson, L. F. Lindoy, O. A. Matthews,
G. V. Meehan, A. N. Sobolev, A. H. White, Aust. J. Chem.
1994, 47, 1155; (b) A. H. M. Elwahy, A. A. Abbas, Tetrahedron
2000, 56, 885.
7. (a)K. R. Adam, S.P. H. Arshad, D. S.Baldwin, P. A. Duckworth,
A. J. Leong, L. F. Lindoy, B. J. McCool, M. McPartlin,
B. A. Tailor, P. A. Tasker, Inorg. Chem. 1994, 33, 1194;
(b) L. H. Doerrer, S. J. Lippard, Inorg. Chem. 1997, 36, 2554;
(c) K.-M. Park, S.-T. Moon, Y. J. Kang, H. J. Kim, J. Seo,
S. S. Lee, Inorg. Chem. Commun. 2006, 9, 671;
(d) K. S. Choi, D. Kang, J.-E. Lee, J. Seo, S. S. Lee, Bull. Korean
Chem. Soc. 2006, 27, 747.
8. (a) W. N. Setzer, Y. Tang, G. J. Grant, D. G. VanDerveer,
Inorg. Chem. 1991, 30, 3652; (b) C.-D. Wu, P. Ayyappan,
O. R. Evans, W. Lin, Cryst. Growth Des. 2007, 7, 1690;
(c) L.-F. Ma, C.-P. Li, L.-Y. Wang, M. Du, Cryst. Growth
Des. 2010, 10, 2641.
9. (a) N. W. Alcock, E. H. Curzon, P. Moore, C. Pierpoint,
J. Chem. Soc. Dalton Trans. 1984, 605; (b) U. Rajalingam, P.
A. W. Dean, H. A. Jenkins, M. Jennings, J. M. Hook, Can. J.
Chem. 2001, 79, 1330; (c) H. Keypour, R. Azadbakht,
H. Khavasi, Polyhedron 2008, 27, 648; (d) W.-B. Lin, H.-
C. Liang, J.-D. Chen, T.-C. Keng, J.-C. Wang, Inorg. Chim. Acta
2002, 336, 157.
determination were carried out using the SHELXTL pack-
age.14 In all cases, all non-hydrogen atoms were refined aniso-
tropically, and all hydrogen atoms were placed in idealized
positions and refined isotropically in a riding manner along
with the their respective parent atoms. Relevant crystal data
collection and refinement data for the crystal structures of
1–2 are summarized in Table 1.
Acknowledgment. This work was supported by Kyungnam
University Foundation Grant, 2013.
Supporting Information. Crystallographicdata forthe struc-
tures reported here have been deposited with CCDC
(Deposition No. CCDC-1051140 (1) and CCDC-1051141
(2)). These data can be obtained free of charge via http://
www.ccdc.cam.ac.uk/conts/retrieving.html or from CCDC,
12 Union Road, Cambridge CB2 1EZ, UK, e-mail: depos-
it@ccdc.cam.ac.uk.
References
1. (a) R. M. Izatt, K. Pawlak, J. S. Bradshaw, Chem. Rev. 1991, 91,
1721; (b) L. F. Lindoy, The Chemistry ofMacrocyclic Complexes,
Cambridge University Press, Cambridge, 1989; (c) R. M. Izatt,
K. Pawlak, J. S. Bradshaw, Chem. Rev. 1995, 95, 2529.
2. L. F. Lindoy, G. V. Meehan, I. M. Vasilescu, H. J. Kim, J.-E. Lee,
S. S. Lee, Coord. Chem. Rev. 2010, 254, 1713.
10. (a) Y. Habata, M. Ikeda, S. Yamada, H. Takahashi, S. Ueno,
T. Suzuki, S. Kuwahara, Org. Lett. 2012, 14, 4576;
(b) O.-S. Jung, Y. J. Kim, Y.-A. Lee, H. K. Chae, H. G. Jang,
J. Hong, Inorg. Chem. 2001, 40, 2105.
3. (a) S. Kim, L. F. Lindoy, S. S. Lee, Coord. Chem. Rev. 2014,
280, 176; (b) M. J. D. Champion, J. M. Dyke,
W. Levason, M. E. Light, D. Pugh, H. Bhakhoa, L. Rhyman,
P. Ramasami, G. Reid, Inorg. Chem. 2015, 54, 2497.
4. (a) R. Menif, A. E. Martell, P. J. Squattrito, A. Clearfield, Inorg.
Chem. 1990, 29, 4723; (b) S. Brooker, Coord. Chem. Rev. 2001,
222, 33; (c) S. A. Cameron, S. Brooker, Inorg. Chem. 2011,
50, 3697.
5. (a) H.-H. Lee, I.-H. Park, S. S. Lee, Inorg. Chem. 2014, 53, 4763;
(b) A. D. Siewe, H. Ju, S. S. Lee, Bull. Korean Chem. Soc. 2013,
34, 725; (c) H. J. Kim, I. Yoon, S. Y. Lee, J. Seo, S. S. Lee,
Tetrahedron Lett. 2007, 48, 8464.
11. MOGUL, Cambridge Crystallographic Database, Cambridge,
UK, 2006.
12. (a) C. X. Cui, M. Kertesz, Inorg. Chem. 1990, 29, 2568;
(b) V. Mckee, J. Nelson, D. J. Speed, R. M. Town, J. Chem.
Soc. Dalton Trans. 2001, 3641; (c) M. O. Awaleh, A. Badia,
F. Bisse, Cryst. Growth Des. 2004, 5, 1897.
13. Bruker, APEX2 Version 2009.1-0 Data Collection and Proces-
sing Software; Bruker AXS Inc., Madison, Wisconsin,
USA, 2008.
14. Bruker, SHELXTL-PC Version 6.22: Program for Solution and
Refinement of Crystal Structures; Bruker AXS Inc., Madison,
Wisconsin, USA, 2001.
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