(II), Copper(II), and Nickel(II) Complexes of Bis(tripodal) Diamide Ligands - Reversible Switching of the Amide Coordination Mode upon Deprotonation

Article abstract of DOI:10.1002/ejic.200901145

A series of dinuclear Zn(II), Cu(II) and Ni(II) complexes of two new bis-tripodal ligands with aromatic (H₂-4a) and aliphatic (H ₂-4b) diamide spacers has been synthesized and structurally characterized. Each of the two tripodal entities of the neutral dinucleating ligands coordinates to one metal ion via three amine functions and a carbonyl oxygen atom of the amide groups. Either trifluoroacetate counterions or solvent molecules complete the trigonal-bipyramidal (Zn, Sa), square-pyramidal (Cu, 6a and 6b), and octahedral (Ni, 7a and 7b) coordination environment at the metal centers. Complexes 5a, 6a, and 7a with the phenylene-bridged diamide ligand are readily deprotonated by potassium tert-butoxide effecting a rearrangement of the dinuclear complexes. In the resulting zinc and copper complexes 8 and 9, one of the metal centers is coordinated by three amine functions of a tripodal subunit and the two amidate nitrogen atoms of the deprotonated ligand 4a^2- while the coordination geometry of the second metal atom remains unchanged. The analogous nickel compound crystallizes as neutral tetranuclear complex (10) ₂ with intermolecular coordination of two amide carbonyl oxygen atoms to the nickel atoms of an adjacent dinuclear complex. The resulting coordination mode with binding of all four donor functions of the diamide spacer to three discrete metal centers is to date unprecedented for ortho-phenylene-bridged acetamides. The rearrangement upon deprotonation has been shown to be fully reversible and the starting complexes can be retrieved upon protonation of the two amidate functions. Synthesis of the trinuclear zinc complex 11 with coordination of the two amidate nitrogen atoms to a third metal center was achieved via deprotonation of (H₆-4a)-(CF ₃CO₂)₄ by three equivalents of diethylzinc. In protic solvents 11 rapidly rearranges to give the entropically favored dinuclear complex 8 with elimination of one equivalent of zinc trifluoroacetate.

Full text of DOI:10.1002/ejic.200901145

FULL PAPER
DOI: 10.1002/ejic.200901145
Zinc(II), Copper(II), and Nickel(II) Complexes of Bis(tripodal) Diamide
Ligands – Reversible Switching of the Amide Coordination Mode upon
Deprotonation
F. Ekkehardt Hahn,*[a] Henning Schröder,[a] Tania Pape,[a] and Florian Hupka[a]
Keywords: Tripodal ligands / Dimetallic complexes / N,O ligands / Amides / Coordination modes
A series of dinuclear Zn(II), Cu(II) and Ni(II) complexes of
the second metal atom remains unchanged. The analogous
two new bis-tripodal ligands with aromatic (H2-4a) and ali- nickel compound crystallizes as neutral tetranuclear complex
phatic (H2-4b) diamide spacers has been synthesized and
structurally characterized. Each of the two tripodal entities of
the neutral dinucleating ligands coordinates to one metal ion
via three amine functions and a carbonyl oxygen atom of the
amide groups. Either trifluoroacetate counterions or solvent
molecules complete the trigonal-bipyramidal (Zn, 5a),
square-pyramidal (Cu, 6a and 6b), and octahedral (Ni, 7a and
7b) coordination environment at the metal centers. Com-
plexes 5a, 6a, and 7a with the phenylene-bridged diamide
ligand are readily deprotonated by potassium tert-butoxide
effecting a rearrangement of the dinuclear complexes. In the
resulting zinc and copper complexes 8 and 9, one of the
metal centers is coordinated by three amine functions of a
tripodal subunit and the two amidate nitrogen atoms of the
deprotonated ligand 4a2– while the coordination geometry of
(10)2 with intermolecular coordination of two amide carbonyl
oxygen atoms to the nickel atoms of an adjacent dinuclear
complex. The resulting coordination mode with binding of all
four donor functions of the diamide spacer to three discrete
metal centers is to date unprecedented for ortho-phenylene-
bridged acetamides. The rearrangement upon deprotonation
has been shown to be fully reversible and the starting com-
plexes can be retrieved upon protonation of the two amidate
functions. Synthesis of the trinuclear zinc complex 11 with
coordination of the two amidate nitrogen atoms to a third
metal center was achieved via deprotonation of (H6-4a)-
(CF3CO2)4 by three equivalents of diethylzinc. In protic sol-
vents 11 rapidly rearranges to give the entropically favored
dinuclear complex 8 with elimination of one equivalent of
zinc trifluoroacetate.
ortho-phenylene[3,4] or ethylene[3,5] spacer. Analogous li-
gands with aliphatic amine functions instead of the pyridine
rings are also known.[6]
These ligands are readily deprotonated and usually bind
to metal ions with two amidate and two additional nitrogen
donors, often providing an essentially planar donor envi-
ronment. For the ortho-phenylene-bridged ligand type, the
deprotonated diamide can act to some degree as an anionic
analog of ortho-phenanthroline.
Alsfasser et al. have synthesized a series of tetradentate
tripodal ligands with amide donor groups by attaching dif-
ferent amino acids or small peptide chains to a bis(2-pyr-
idylmethyl)amine unit. The neutral ligands coordinate to
zinc(II), copper(II) and nickel(II) with the pyridyl donor
functions, the tertiary amine, and the amide carbonyl oxy-
gen atom.[7] For selected zinc(II) complexes, a rearrange-
ment of the ligand with coordination of the amidate nitro-
gen atom was observed upon deprotonation. This switching
of the amide coordination mode has been to be fully revers-
ible upon protonation with hydrochloric acid.[8] Similar pH-
dependent rearrangements have been reported by other
groups for complexes with tripodal ligands featuring amine
and amide donor groups.[9]
Introduction
Carboxamides are not only ubiquitous in the biosphere
as essential parts of proteins, but they are also versatile and
interesting ligands in synthetic coordination chemistry.
Neutral amides exclusively coordinate to metal ions via the
lone pair at the carbonyl oxygen atom, as the lone pair at
the nitrogen is delocalized over the whole amide group and,
consequently, not available for metal coordination. On the
other hand, deprotonated amides preferably coordinate to
metal ions via their amidate nitrogen atom.[1]
Due to the presence of N-donor functions in many natu-
rally occurring metalloproteins, ligands combining amide
and pyridine donor groups have been intensively investi-
gated.[2] A well-known group of these ligands are bis(pyrid-
ine-2-carboxamides), consisting of two carboxamide units
connected by a suitable amide-N-bridging group, mostly an
[a] Institut für Anorganische und Analytische Chemie, Westfäli-
sche Wilhelms-Universität Münster,
Corrrensstraße 30, 48149 Münster, Germany
Fax: +49-251-833-3108
E-mail: fehahn@uni-muenster.de
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejic.200901145.
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Compared to their analogs with aromatic pyridyl donor groups occurs upon deprotonation, resulting in the decom-
groups, tripodal ligands with aliphatic amine groups have position of the ligand by elimination of the bridging di-
attracted much less attention. Due to their higher flexibility, amine.
the aliphatic ligands exhibit a more variable coordination
The dinuclear zinc(II), copper(II), and nickel(II) com-
behavior toward metal ions. The influence of the ligand arm plexes 5, 6, and 7 of the neutral ligands H2-4 were obtained
lengths on the coordination geometry of the copper(II)[10] via in situ deprotonation of the trifluoroacetate salts (H6-
and nickel(II)[11] complexes with a series of symmetric and 4)(CF3CO2)4 by acetate or acetylacetonate ligands of the
unsymmetric aliphatic tetraamine ligands has been studied. metal precursors (Scheme 2). Decomposition of the ligand
Herein we report on the synthesis and characterization upon deprotonation was not observed under these condi-
of two new protonated bis(tripodal) ligands (H6-4a)- tions, as coordination of the generated primary amine func-
(CF3CO2)4 and (H6-4b)(CF3CO2)4 (Scheme 1) featuring the tions to the transition metal ion prevents the intramolecular
two adjacent amide groups of bis(pyridinecarbox- attack at the carbonyl group. Complexes of types 5, 6, and
amides) linked to two tridentate aliphatic triamines. The co- 7 have been obtained in good yields with the higher yields
ordination chemistry of the neutral deprotonated ligands found for the complexes bearing ligand H2-4a with the aro-
with zinc(II), copper(II), and nickel(II) will be described in matic spacer. Crystals of 5a·MeOH, 6a·MeOH, 6b·2DMF,
addition to the unusual behaviour observed for the com- 7a(MeOH)2·0.5MeOH, and 7b·2MeCN suitable for X-ray
plexes with the o-phenylene-bridged ligand upon further de- diffraction analyses were obtained by slow diffusion of di-
protonation. .
ethyl ether into a solution of the complexes in either meth-
anol, acetonitrile, or DMF.
Scheme 2. Synthesis of the symmetric dinuclear complexes of types
5, 6, and 7 bearing the neutral diamide ligands H2-4a and H2-4b.
Scheme 1. Synthesis of the bis(tripodal) trifluoroacetate salts (H6-
4)(CF3CO2)4 with aromatic and aliphatic spacers.
The X-ray structure analyses for complexes of types 5–7
(see Figures 1, 2, and 3) show each of the metal centers
coordinated by the three amine donors and the carbonyl
oxygen atom of the tripodal entities. In the solid state, the
coordination spheres of the metals are completed by one
Results and Discussion
The protonated diamide ligands of type (H6-4)(CF3CO2)4 (Zn, Cu) or two (Ni) trifluoroacetate counterions with the
were synthesized by substitution of the bromides in com- exception of 7a(MeOH)2·0.5MeOH, where only one trifluo-
pounds of type 1 under basic conditions with amine 2, bear- roacetato anion coordinates to each metal center in ad-
ing tert-butoxycarbonyl (Boc) protecting groups at its pri- dition to one methanol molecule. The observation of only
mary amine functions (Scheme 1). This reaction yields the one set of signals for the counterions in the 13C NMR spec-
Boc-protected diamides of type 3. Subsequent removal of trum of the zinc complexes 5a and 5b indicates the facile
the Boc-protecting groups by treatment with trifluoroacetic displacement of the coordinated trifluoroacetato ions in
acid leads to precipitation of the tetraprotonated trifluoro- solution.
acetate salts (H6-4)(CF3CO2)4. The molecular structure of
The structure analysis of complex 5a·MeOH reveals a
(H6-4a)(CF3CO2)4 has been determined and is described in trigonal-bipyramidal coordination environment for both
the Supporting Information. The neutral diamide ligands metal centers [τ[12] = 0.73 (Zn1) and τ = 0.96 (Zn2)]. The
of type H2-4 could not be isolated, as an intramolecular axial positions are occupied by the tertiary amine function
attack of the primary amine functions at the carbonyl and a trifluoroacetato ligand. The Zn–Ntert distances [Zn1–
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Complexes of Bis(tripodal) Diamide Ligands
Figure 1. Molecular structures of the complex cation in 5a·MeOH
(uncoordinated counterions and hydrogen atoms except amide N–
H protons are omitted for clarity). Selected bond lengths [Å] and
angles [°]: Zn1–O2 2.065(2), Zn1–O5 1.997(3), Zn1–N1 2.241(3),
Zn1–N2 2.052(3), Zn1–N3 2.043(4), Zn2–O1 2.053(2), Zn2–O3
2.008(3), Zn2–N6 2.257(3), Zn2–N7 2.034(4), Zn2–N8 2.025(4);
N1–Zn1–O5 166.84(11), N1–Zn1–O2 77.53(10), N1–Zn1–N2
83.21(13), N1–Zn1–N3 81.32(12), O2–Zn1–N2 107.74(14), O2–
Zn1–N3 121.23(13), N2–Zn1–N3 123.3(2), N6–Zn2–O3
164.45(11), N6–Zn2–O1 77.98(10), N6–Zn2–N7 82.59(14), N6–
Zn2–N8 88.84(14), O1–Zn2–N7 123.26(15), O1–Zn2–N8
109.19(14), N7–Zn2–N8 120.5(2).
Figure 2. Molecular structures of the complex cations in 6a·MeOH
(top) and 6b·2DMF (bottom, uncoordinated counterions and hy-
drogen atoms except amide N–H protons are omitted for clarity).
Selected bond lengths [Å] and angles [°] for 6a·MeOH: Cu1–O1
2.336(3), Cu1–O3 1.979(3), Cu1–N1 2.072(4), Cu1–N2 2.004(4),
Cu1–N3 1.980(4), Cu2–O2 2.218(3), Cu2–O6 1.980(3), Cu2–N5
2.070(3), Cu2–N6 2.007(4), Cu2–N7 1.981(3); O1–Cu1–O3
92.90(12), O1–Cu1–N1 78.61(12), O1–Cu1–N2 94.43(13), O1–
Cu1–N3 96.28(15), O3–Cu1–N1 170.98(14), O3–Cu1–N2
92.41(14), O3–Cu1–N3 99.25(15), N1–Cu1–N2 85.26(15), N1–
Cu1–N3 84.9(2), N2–Cu1–N3 163.7(2), O2–Cu2–O6 93.06(12),
O2–Cu2–N5 80.35(12), O2–Cu2–N6 93.21(14), O2–Cu2–N7
108.16(14), O6–Cu2–N5 173.14(13), O6–Cu2–N6 92.36(13), O6–
Cu2–N7 98.05(13), N5–Cu2–N6 86.13(13), N5–Cu2–N7 85.92(13),
N6–Cu2–N7 155.55(15). Selected bond lengths [Å] and angles [°]
for 6b·2DMF: Cu1–O1 2.2585(10), Cu1–O2 1.9683(10), Cu1–N1
2.0667(11), Cu1–N2 1.9972(13), Cu1–N3 1.9936(13); O1–Cu1–O2
93.16(4), O1–Cu1–N1 80.38(4), O1–Cu1–N2 110.15(5), O1–Cu1–
N3 95.60(5), O2–Cu1–N1 173.53(4), O2–Cu1–N2 96.30(5), O2–
Cu1–N3 94.83(5), N1–Cu1–N2 85.63(5), N1–Cu1–N3 86.28(5),
N2–Cu1–N3 151.23(5).
N1 2.241(3) Å, Zn2–N6 2.257(3) Å] are considerably longer
than the Zn–Nprimary separations [range 2.025(4)–
2.052(3) Å]. The Zn–Oamide distances [Zn1–O2 2.053(2) Å,
Zn2–O1 2.065(2) Å] are slightly longer than the Zn–Oacetato
distances [Zn1–O5 1.997(3) Å, Zn2–O1 2.008(3) Å].
The molecular structures of the copper complexes
6a·MeOH and 6b·2DMF also exhibit pentacoordinate
metal centers. Both compounds crystallize in the triclinic
¯
space group P1 with Z = 2 for 6a·MeOH and Z = 1 for
6b·2DMF (inversion center at the midpoint of the C7–C7*
bond). The methanol molecule and some of the fluoride
atoms are disordered in 6a·MeOH.
In both 6a·MeOH and 6b·2DMF, the copper ions adopt
a tetragonal-pyramidal coordination geometry (6a·MeOH:
τ = 0.12 for Cu1 and τ = 0.29 for Cu2; 6b·2DMF: τ = 0.37)
with the amide oxygen atoms residing in the apical posi-
tions (Figure 2). The Cu1–Oapical bond lengths [6a·MeOH: counteranions with partially disordered fluorine atoms. All
2.336(3) Å and 2.218(3) Å; 6b·2DMF: 2.2585(10) Å] are no- Ni–N and Ni–O distances fall in a narrow range of
tably longer than the equatorial bond lengths which exhibit 2.095(3)–2.103(3) Å [7a(MeOH)2·0.5MeOH] and 2.058(3)–
approximately equidistant lengths of about 2.0 Å.
2.113(4) Å (7b·2MeCN).
The metal atoms in the dinickel complexes 7a(MeOH)2·
The metal-donor bond lengths and angles for all com-
0.5MeOH and 7b·2MeCN are coordinated in a distorted plexes of types 5–7 with the neutral diamide ligands fall in
octahedral fashion (Figure 3). Both tetrafluoroacetate the range reported previously for similar complexes with an
anions per NiII are coordinated to the metal centers in unbridged tripodal ligand with amide and pyridyl donor
7b·2MeCN leading to a neutral complex. The metal centers functions.[7] Complexes with ligand H2-4a possess amide
in compound 7a(MeOH)2·0.5MeOH are coordinated by a groups with the NCO units twisted out of the plane of the
tetrafluoroacetate anion and a methanol molecule. The re- aromatic spacer, most likely caused by the steric repulsion
maining two tetrafluoroacetate anions crystallize as of the two amide protons. Due to the more flexible ethylene
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accompanied by a rearrangement in the coordination envi-
ronment of one of the metal centers in the dinuclear com-
plexes. The two amidate nitrogen atoms formed by depro-
tonation now coordinate to one metal center while the coor-
dination geometry of the second metal center remains un-
changed. The switch in the coordination mode is fully re-
versible upon protonation of the amidate nitrogen atoms
with trifluoroacetic acid (Scheme 3). For the copper com-
plex 6a the rearrangement of the coordination sphere upon
deprotonation to give complex 9 is accompanied by a char-
acteristic color change from blue for 6a to green for 9.
Figure 3. Molecular structures of the complex cations in
7a(MeOH)2·0.5MeOH (top, uncoordinated counterions and hydro-
gen atoms except amide N–H protons are omitted for clarity) and
of 7b in 7b·2MeCN. Selected bond lengths [Å] and angles [°] for
7aMeOH)2·0.5MeOH: Ni1–O1 2.065(3), Ni1–O3 2.061(3), Ni1–O5
2.073(3), Ni1–N1 2.100(4), Ni1–N2 2.095(4), Ni1–N3 2.088(4),
Ni2–O2 2.083(3), Ni2–O6 2.103(3), Ni2–O8 2.059(3), Ni2–N6
2.090(3), Ni2–N7 2.075(4), Ni2–N8 2.087(4); O1–Ni1–O3
172.49(12), O1–Ni1–O5 91.58(13), O1–Ni1–N1 81.86(12), O1–Ni1–
N2 92.56(14), O1–Ni1–N3 93.02(13), N1–Ni1–N2 83.8(2), N1–
Ni1–N3 83.78(15), N2–Ni1–N3 165.5(2), O2–Ni2–O6 175.76(13),
O2–Ni2–O8 91.78(13), O2–Ni2–N6 81.73(12), O2–Ni2–N7
87.91(14), O2–Ni2–N8 97.82(13), N6–Ni2–N7 84.98(14), N6–Ni2–
N8 82.64(14), N7–Ni2–N8 165.5(2). Selected bond lengths [Å] and
angles [°] for 7b·2MeCN: Ni1–O1 2.093(3), Ni1–O3 2.090(3), Ni1–
O5 2.067(3), Ni1–N1 2.095(4), Ni1–N2 2.106(4), Ni1–N3 2.091(4),
Ni2–O2 2.082(3), Ni2–O7 2.058(3), Ni2–O9 2.082(3), Ni2–N6
2.093(4), Ni2–N7 2.113(4), Ni2–N8 2.097(4); O1–Ni1–O3
172.49(11), O1–Ni1–O5 96.90(12), O1–Ni1–N1 81.90(12), O1–Ni1–
N2 91.31(13), O1–Ni1–N3 94.58(14), N1–Ni1–N2 83.42(14), N1–
Ni1–N3 83.25(14), N2–Ni1–N3 164.51(15), O2–Ni2–O7 93.15(12),
O2–Ni2–O9 176.27(13), O2–Ni2–N6 82.22(13), O2–Ni2–N7
90.13(13), O2–Ni2–N8 97.95(14), N6–Ni2–N7 83.91(14), N6–Ni2–
N8 82.85(15), N7–Ni2–N8 163.39(15).
Scheme 3. Reversible deprotonation of complexes 5a–7a ac-
companied by a structural rearrangement to yield the unsymmetri-
cal complexes 8–10.
Crystals of 8·3MeOH, 9·MeOH, and (10)2·2MeOH·
2Et2O suitable for X-ray diffraction analyses were obtained
by slow diffusion of diethyl ether into methanol solutions
of the complexes. The dinuclear zinc complex in 8·3MeOH
(Figure 4) features two different pentacoordinate zinc
atoms. One of them (Zn2) exhibits a coordination environ-
ment which is unchanged compared to the starting complex
5a with the zinc atom coordinated by three aliphatic amine
donors from the tripodal subunit, one amide oxygen atom
and one oxygen atom from a trifluoroacetate anion. The
second zinc atom (Zn1) is also coordinated by three ali-
phatic amine donors in addition to two amidate nitrogen
atoms with the amide oxygen atom remaining uncoordi-
nated. The coordination geometry of atom Zn1 is also best
described as trigonal-bipyramidal (τ = 0.67) with the terti-
ary amine (N5) and one of the amidate donor functions
(N1) in the axial positions. The Zn–Ntert bond length is the
spacer, the arrangement of the two metal centers in the longest Zn-donor separation for both zinc atoms [Zn1–N5
complexes derived from the aliphatic ligand 4b-H2 are 2.270(3) Å, Zn2–N6 2.253(3) Å]. Although zinc atom Zn1
mainly determined by crystal packing effects.
is slightly displaced from the plane of the aromatic ring,
Complexes 5a–7a containing the phenylene-bridged di- bond lengths and angles involving atoms Zn1, N1 and N2
amide ligand are readily deprotonated at the amide func- correspond well to those reported for a mononuclear zinc
tions by potassium tert-butoxide in methanol to yield the complex of a bis(tripodal) amine ligand with an ortho-phen-
complexes 8–10 (Scheme 3). The deprotonation reaction is anthroline spacer.[13]
912
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Complexes of Bis(tripodal) Diamide Ligands
Figure 4. Molecular structure of the complex cation in 8·3MeOH
(hydrogen atoms are omitted for clarity). Selected bond lengths [Å]
and angles [°]: Zn1–N1 2.089(3), Zn1–N2 2.008(3), Zn1–N3
2.063(3), Zn1–N4 2.063(3), Zn1–N5 2.270(3), Zn2–O2 2.027(2),
Zn2–O3 2.034(3), Zn2–N6 2.252(3), Zn2–N7 2.066(3), Zn2–N8
2.055(3); N1–Zn1–N5 160.77(11), N2–Zn1–N3 117.44(12), N2–
Zn1–N4 120.60(13), N3–Zn1–N4 114.48(13), O3–Zn2–N6
172.11(11), O3–Zn2–N6 172.11(11), O2–Zn2–N7 131.01(12), O2–
Zn2–N8 110.13(12), N7–Zn2–N8 109.84(13).
Figure 6. Molecular structure of the tetranuclear nickel complex
in (10)2·2MeOH·2Et2O (hydrogen atoms are omitted for clarity).
Selected bond lengths [Å] and angles [°]: Ni1–N1 2.122(2), Ni1–N2
2.106(2), Ni1–N3 2.108(2), Ni1–N4 2.004(2), Ni1–N5 2.094(2),
Ni1–O21 2.229(15), Ni2–N6 2.083(2), Ni2–N7 2.081(2), Ni2–N8
2.104(2), Ni2–O1 2.1744(15), Ni2–O2 2.0455(14), Ni2–O23
2.0531(15); N1–Ni1–N5 161.11(7), N2–Ni1–N3 160.05(7), N4–
Ni1–O21 171.22(6), N6–Ni2–O23 174.98(7), N7–Ni2–O2
163.64(6), N8–Ni2–O1 174.03(6).
The unsymmetrical copper complex 9·MeOH (Figure 5)
contains a tetragonal-pyramidal copper atom Cu2 exhibit-
ing a coordination environment which is identical and bond
parameters which are not significantly different from those
observed for the tetragonal-pyramidal copper atoms in
complex 6a·MeOH. Copper atom Cu1 adopts a coordina-
tion geometry in between tetragonal-pyramidal and trigo-
nal-bipyramidal (τ-value of 0.58). The Cu1–Namidate bond
lengths are the shortest Cu1-donor separations and are in
good agreement with the corresponding bond lengths ob-
served for the copper complex with a deprotonated ortho-
phenylenediamide ligand.[6]
Both of the two different nickel centers in one molecule
of 10 exhibit a distorted octahedral coordination geometry.
Atom Ni1 is coordinated by the two amidate nitrogen
atoms, three amines of one tripodal subunit, and a trifluoro-
acetate counterion. Atom Ni2 has a coordination environ-
ment similar to the nickel atoms in complex 7a(MeOH)2
with the methanol donor in 7a(MeOH)2 replaced by an
amide oxygen atom from a neighboring molecule of 10. The
most remarkable structural feature of (10)2 is the unusual
coordination mode of the doubly deprotonated diamide
spacer of the deprotonated ligand 4a2– which coordinates
with all four donor atoms of the two amidate groups (N4,
N5, O1, O2) to three different metal centers (Ni1, Ni2 and
Ni2*). Although such a binding mode is common for 1,2-
bis(oxamato)arenes[14] it has not been reported for ortho-
phenylene-bridged acetamides yet.
Reaction of the trifluoroacetate salt (H6-4a)(CF3CO2)4
with three equivalents of diethylzinc results in the formation
of the trinuclear zinc complex 11 (Scheme 4) via deproton-
ation of the four primary ammonium groups and of the two
Figure 5. Molecular structure of the complex cation in 9·MeOH
(hydrogen atoms are omitted for clarity). Selected bond lengths [Å]
and angles [°]: Cu1–N1 1.982(6), Cu1–N2 1.929(6), Cu1–N3
2.045(6), Cu1–N7 2.143(6), Cu1–N8 2.159(7), Cu2–O2 2.196(5),
Cu2–O3 1.953(6), Cu2–N4 2.043(6), Cu2–N5 1.993(7), Cu2–N6
2.007(8); N1–Cu1–N3 165.3(2), N2–Cu1–N7 126.7(3), N2–Cu1–
N8 130.6(3), N7–Cu1–N8 98.3(3), O2–Cu2–O3 90.3(2), O2–Cu2–
N4 81.5(2), O2–Cu2–N5 113.0(3), O2–Cu2–N6 89.7(3), O3–Cu2–
N4 170.9(3), O3–Cu2–N5 94.7(3), O3–Cu2–N6 98.3(3), N4–Cu2–
N5 85.1(3), N4–Cu2–N6 85.6(3), N5–Cu2–N6 153.8(3).
1
amide groups of the aromatic spacer. Both the H and 13C
NMR spectra of 11 show only one set of resonances indica-
tive for the formation of a symmetrical complex. Coordina-
tion of the two amidate nitrogen atoms of the deprotonated
ligand 4a2– to the zinc center leads to a higher degree of
coplanarity of the aromatic ring and the amides NCO units
The nickel complex 10 dimerizes upon crystallization via compared to the dinuclear complex 5a. The electron with-
formation of two intermolecular amide-O–Ni interactions drawing effect of the zinc ions coordinated to the amide
(O1–Ni2 and O1*–Ni2) and formation of the tetranuclear carbonyl oxygen atoms is mediated by the extended π-sys-
complex (10)2·2MeOH·2Et2O in the solid state. The tetra- tem formed this way causing a considerable deshielding of
nuclear complex resides on a crystallographic inversion cen- the aromatic protons in the ortho-position to the amide sub-
ter (Figure 6).
stituents (δ = 7.76 ppm for 5a, δ = 8.85 ppm for 11).
Eur. J. Inorg. Chem. 2010, 909–917
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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913

F. E. Hahn, H. Schröder, T. Pape, F. Hupka
FULL PAPER
dried by standard methods and freshly distilled prior to use. NMR
spectra were recorded at 298 K with Bruker AC 200 (200 MHz) or
Bruker AMX 400 (400 MHz) spectrometers and are reported rela-
tive to the solvent signal. IR spectra were measured with a Bruker
Vector 22 IR spectrometer. Mass spectra were obtained with a
Bruker Reflex IV (MALDI) spectrometer. Elemental analyses were
performed with a Vario EL III CHNS analyzer. The N,NЈ-bis(bro-
moacetyl)diamines 1a and 1b, bis(2-tert-butoxycarbonylamino-
ethyl)amine (2), and diamide 3a were synthesized as described pre-
viously.[15,16] Consistent elemental analyses of the ligand precursors
(H6-4a)(CF3CO2)4 and (H6-4b)(CF3CO2)4 and for the metal com-
plexes were difficult to obtain due to the presence of the trifluoro
acetate ions.
Diamide 3b: Diamide 3b was synthesized as described for diamide
3a[16] from 1b (7.55 g, 25 mmol) and bis(2-tert-butoxycarbonylami-
noethyl)amine (2) (15.15 g, 50 mmol); yield 14.99 g (20.1 mmol,
1
80%) of a colorless solid. H NMR (400.1 MHz, CDCl3): δ = 7.39
Scheme 4. Synthesis of the symmetric trinuclear zinc complex 11
and degradation to the unsymmetric dinuclear complex 8 in meth-
anol.
[s, 2 H, NHC(O)CH2], 6.11 (s, 4 H, NHBoc), 3.33 [s, 4 H, NHC(O)-
CH2N], 2.96 (t, 8 H, NCH2CH2NHBoc), 2.80 [s, 4 H, CH2NHC-
(O)CH2N], 2.28 (t, 8 H, NCH2CH2NHBoc), 1.25 [s, 36 H, C(O)-
OC(CH3)3] ppm. 13C NMR (100.6 MHz, CDCl3): δ = 171.0
[NHC(O)CH2], 156.7 [C(O)OtBu], 79.1 [C(O)OC(CH3)3], 58.4
[NHC(O)CH2N], 55.0 (NCH2CH2NHBoc), 39.0 [CH2NHC(O)-
CH2N], 38.3 (NCH2CH2NHBoc), 28.5 [C(O)OC(CH3)3] ppm.
MALDI-MS (TOF, positive ions): m/z = 785 [M + K]+, 769 [M +
Na]+, 747 [M + H]+. C34H66N8O10 (746.95): calcd. C 54.67, H 8.91,
N 26.25; found C 54.70, H 8.89, N 26.29.
Complex 11 is quickly degraded in methanol to give the
unsymmetrical complex 8 (Scheme 4) obtained previously
by deprotonation of complex 5a. The protic solvent facili-
tates the entropically favored elimination of one equivalent
of zinc trifluoroacetate associated with a rearrangement of
the complex, as was observed for 5a upon deprotonation.
Crystals of the decomposition product of 11 with the com-
position [Zn(CF3CO2)(4a)](CF3CO2)·[Zn(4a)(MeOH)][Zn-
(CF3CO2)4] were obtained by slow diffusion of diethyl ether
into a solution of the compound in methanol. The structure
analysis (see Supporting Information) shows that the elimi-
nation and rearrangement to the unsymmetrical dinuclear
zinc complex did indeed occur. The asymmetric unit con-
tains one formula unit of [Zn(CF3CO2)(4a)]CF3CO2 8 and
another dinuclear zinc complex also with an unsymmetrical
coordinated ligand 4a and a [Zn(CF3CO2)4]2– counterion.
The bond parameters of the two complex anions are nearly
identical and match those for 8 obtained by deprotonation
of complex 5a.
Trifluoroacetate Salts (H6-4a)(CF3CO2)4 and (H6-4b)(CF3CO2)4:
For the preparation of (H6-4a)(CF3CO2)4 diamide 3a (1.34 g,
1.7 mmol) was dissolved in chloroform (50 mL) and trifluoroacetic
acid (3.8 mL, 51 mmol) was added. After stirring at ambient tem-
perature for 12 h the solvent was removed under reduced pressure.
The oily solid obtained was dissolved in acetonitrile and precipi-
tated by addition of chloroform. The colorless precipitate was col-
lected by filtration and was dried in vacuo. Salt (H6-4b)(CF3CO2)4
was synthesized in the same way starting from diamide 3b (1.61 g,
2.2 mmol) and trifluoroacetic acid (4.9 mL, 66 mmol).
(H6-4a)(CF3CO2)4: Yield 1.02 g (1.2 mmol, 71%) of a colorless so-
lid. 1H NMR (200.1 MHz, CD3OD): δ = 7.60 (m, 2 H, Ar-CH),
7.24 (m, 2 H, Ar-CH), 3.59 [s, 4 H, NHC(O)CH2N], 3.10 (t, 8 H,
NCH2CH2NH3+), 2.95 (t, 8 H, NCH2CH2NH3+) ppm. 13C NMR
(50.3 MHz, CD3OD): δ = 173.6 [NHC(O)], 132.2 (Ar-Cipso), 128.0,
127.6 (Ar-C), 58.5 [NHC(O)CH2N], 54.8 (NCH2CH2NH3+), 39.5
(NCH2CH2NH3+) ppm. 19F NMR (188.3 MHz, CD3OD): δ =
Conclusions
–
–72.5 (CF3CO2 ) ppm. MALDI-MS (TOF, positive ions): m/z =
The neutral diamide ligands H2-4a and H2-4b preferably
coordinate to divalent metal ions like Zn2+, Cu2+ or Ni2+
via the aliphatic amine donors and the carbonyl oxygen
417 [(H -4a)+Na]+; 395 [(H -4a)+H]+. IR (KBr): ν = 3424 (m),
˜
2
2
3282 (w), 3059 (w), 2950 (w), 2928 (w), 1686 (s, CO), 1528 (m,
CO) cm–1. Crystals of (H6-4a)(CF3CO2)4·2MeOH were obtained
atoms of the amide groups. The symmetrical dinuclear com- by diffusion of diethyl ether into a methanol solution of the com-
pound. For an X-ray diffraction analysis of (H6-4a)(CF3CO2)4·
2MeOH see Supporting Information.
plexes 5a, 6a and 7a of the phenylene-bridged ligand H2-4a
are readily deprotonated by alcoholates at the amide func-
tions which causes a rearrangement of the coordinated do-
nor groups and coordination of the generated two amidate
nitrogen atoms to one of the metal centers. This rearrange-
ment is fully reversible by protonation of the amide func-
tions.
(H6-4b)(CF3CO2)4: Yield 1.41 g (1.8 mmol, 82%) of a colorless so-
lid. 1H NMR (400.1 MHz, CD3CN): δ = 8.10 [s, 2 H, NHC(O)],
7.72 (s, 12 H, NCH2CH2NH3+), 3.29 [d, 4 H, CH2NHC(O)], 3.20
[s, NHC(O)CH2N], 3.04 (t, 8 H, NCH2CH2NH3+), 2.77 (t, 8 H,
NCH2CH2NH3+) ppm. 13C NMR (100.6 MHz, CD3CN): δ = 174.0
2
–
1
[NHC(O)], 162.2 (q, JCF = 34 Hz, CF3CO2 ), 118.0 (q, JCF
=
294 Hz, CF3CO2 ), 57.9 [NHC(O)CH2N], 53.4 (NCH2CH2NH3+),
40.1 [CH2NHC(O)], 38.5 (NCH2CH2NH3+) ppm. MALDI-MS
(TOF, positive ions): m/z = 369 [(H2-4b)+Na]+, 347 [(H2-4b)+H]+.
–
Experimental Section
General: All operations were carried out under an atmosphere of
dry argon using Schlenk and vacuum techniques. Solvents were
IR (KBr): ν = 3343 (m), 3066 (m), 2958 (w), 2855 (w), 2718 (w),
˜
2661 (w), 2618 (w), 2530 (w), 1676 (s, CO), 1558 (m, CO) cm–1.
914
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Inorg. Chem. 2010, 909–917

Complexes of Bis(tripodal) Diamide Ligands
General Procedure for the Synthesis of the Dinuclear Complexes 5–
7 Bearing the Neutral Diamide Ligands (H2-4a) and (H2-4b): The
metal precursor (0.4 mmol) was dissolved in methanol (5 mL) and
a solution of the ligand salt (0.2 mmol) in methanol (5 mL) was
added. The reaction mixture was stirred for 12 h at ambient tem-
perature. Subsequently, the solvent was removed under reduced
pressure. The residue was dissolved in acetonitrile (5 mL) and di-
ethyl ether (40 mL) was added. In all cases the complexes precipi-
tated and the precipitates were collected by filtration and were
dried in vacuo. Except when noted, crystals of the complexes suit-
able for X-ray diffraction studies were obtained by slow diffusion
of diethyl ether into a concentrated solution of the complex in
methanol.
[Ni2(CF3CO2)4(H2-4b)] (7b): The complex was synthesized from
Ni(CH3CO2)2·4H2O (100 mg, 0.4 mmol) and (H6-4b)(CF3CO2)4
(160 mg, 0.2 mmol); yield 115 mg (0.13 mmol, 65%) of a blue solid.
Crystals suitable for an X-ray diffraction study were obtained by
slow diffusion of diethyl ether into a solution of the complex in
acetonitrile. MALDI-MS (TOF, positive ions): m/z
= 573
{[Ni2(CF3CO2)(H2-4b)]–2H}+. UV/Vis (methanol): λ = 982, 587,
340 nm. IR (KBr): ν = 3106 (w), 2957 (w), 1684 (s, CO), 1645 (s,
˜
CO) cm–1.
General Procedure for the Deprotonation of Complexes 5a–7a with
Formation of Complexes 8, 9 and 10: A sample of one of the dinu-
clear complexes 5a–7a bearing the neutral diamide ligand
(0.2 mmol) was suspended in acetonitrile (20 mL). To this suspen-
sion was added 0.1  solution of KOtBu in methanol (4.0 mL,
0.4 mmol). The resulting solution was stirred for 1 h at ambient
temperature. Subsequently, diethyl ether (40 mL) was added. Com-
plexes 8–10 precipitated and were collected by filtration and dried
in vacuo. Crystals suitable for an X-ray diffraction study were ob-
tained by slow diffusion of diethyl ether into a solution of the com-
plex in methanol.
[Zn2(CF3CO2)2(H2-4a)](O2CCF3)2 (5a): The complex was synthe-
sized from Zn(acac)2·H2O (113 mg, 0.4 mmol) and (H6-
4a)(CF3CO2)4 (170 mg, 0.2 mmol); yield 168 mg (0.17 mmol, 85%)
1
of a colorless solid. H NMR (400.0 MHz, CD3OD): δ = 7.76 (m,
2 H, Ar-Hortho), 7.37 (m, 2 H, Ar-Hpara), 3.97 [s, 4 H, NHC(O)-
CH2N], 2.95 (m, 16 H, NCH2CH2NH2 and NCH2CH2NH2) ppm.
13C NMR (100.6 MHz, CD3OD): δ = 175.9 [NHC(O)], 163.3 (q,
2JCF = 34.4 Hz, CF3CO2 ), 130.4 (Ar-Cipso), 128.5, 127.2 (Ar-C),
–
[Zn2(CF3CO2)(4a)](CF3CO2) (8): Complex 8 was prepared from
complex 5a (195 mg, 0.2 mmol); yield 123 mg (0.16 mmol, 80%) of
1
–
118.1 (q, JCF = 294 Hz, CF3CO2 ), 58.3 [NHC(O)CH2N], 55.7
(NCH2CH2NH2), 38.5 (NCH2CH2NH2) ppm. MALDI-MS (TOF,
1
a colorless solid. H NMR (400.0 MHz, CD3OD): δ = 8.75 (m, 1
positive ions): m/z = 635 [Zn (CF CO )(H -4a)]–2H+. IR (KBr): ν
˜
2
3
2
2
H, Ar-Hortho), 8.63 (m, 1 H, Ar-Hortho), 6.93 (m, 1 H, Ar-Hpara),
6.86 (m, 1 H, Ar-Hpara), 3.50 {s, 2 H, [C(O)CH2N]}, 3.31 {s, 2 H,
[C(O)CH2N]}, 2.84 (m, 16 H, NCH2CH2NH2 and NCH2CH2NH2)
ppm. 13C NMR (100.6 MHz, CD3OD): δ = 172.9, 172.5 [NHC(O)],
= 3315 (m), 3022 (w), 2970 (w), 2926 (w), 2882 (w), 1691 (s, CO),
1641 (s, CO) cm–1.
[Zn2(CF3CO2)2(H2-4b)](CF3CO2)2 (5b): The complex was synthe-
sized from Zn(CH3CO2)2·2H2O (88 mg, 0.4 mmol) and (H6-
4b)(CF3CO2)4 (160 mg, 0.2 mmol); yield 85 mg (0.09 mmol, 45%)
163.1 (q, 2JCF = 35.7 Hz, CF3CO2 ), 140.6, 139.5 (Ar-Cipso), 124.3,
–
1
–
124.0, 122.6, 122.0 (Ar-C), 118.3 (q, JCF = 292 Hz, CF3CO2 ),
62.2, 61.4 [C(O)CH2N], 55.2, 54.5 (NCH2CH2NH2), 39.4, 38.3
(NCH2CH2NH2) ppm. MALDI-MS (TOF, positive ions): m/z =
1
of a colorless solid. H NMR (400.1 MHz, CD3CN): δ = 9.99 [s, 2
H, NHC(O)], 3.55 [s, 4 H, CH2NHC(O)], 3.51 [m, 4 H, NHC(O)-
635 [Zn (CF CO )(4a)]+. IR (KBr): ν = 3316 (m), 3156 (w), 2949
˜
2
3
2
CH2N], 3.35 (m,
8 H, NCH2CH2NH2), 2.78 (m, 16 H,
(w), 1685 (s, CO), 1593 (m, CO), 1549 (s, CO) cm–1.
NCH2CH2NH2 and NCH2CH2NH2) ppm. 13C NMR (100.6 MHz,
2
[Cu2(CF3CO2)(4a)](CF3CO2) (9): Complex 9 was prepared from
complex 6a (195 mg, 0.2 mmol); yield 117 mg (0.16 mmol, 80%) of
a dark green solid. MALDI-MS (TOF, positive ions): m/z = 631
[Cu2(CF3CO2)(4a)]+. UV/Vis (methanol): λ = 766, 670, 439 (sh)
CD3CN):
δ
=
175.9 [NHC(O)], 161.8 (q, JCF
=
34.0 Hz,
–
1
–
CF3CO2 ), 118.0 (q, JCF = 294 Hz, CF3CO2 ), 56.9 [NHC(O)-
CH2N], 54.8 (NCH2CH2NH2), 40.4 [CH2NHC(O)], 38.1
(NCH2CH2NH2) ppm. MALDI-MS (TOF, positive ions): m/z =
587 {[Zn (CF CO )(H -4b)]–2H}+. IR (KBr): ν = 3443 (m), 3258
˜
nm. IR (KBr): ν = 3266 (m), 3161 (w), 2947 (w), 2889 (w), 1690
˜
2
3
2
2
(s, CO), 1594 (m, CO), 1544 (s, CO) cm–1.
(w), 2961 (w), 2928 (w), 1691 (s, CO), 1629 (s, CO) cm–1.
[Ni2(CF3CO2)2(4a)] (10): Complex 10 was prepared from complex
7a (193 mg, 0.2 mmol); yield 97 mg (0.13 mmol, 65%) of a blue
[Cu2(CF3CO2)2(H2-4a)](CF3CO2)2 (6a): The complex was synthe-
sized from Cu(acac)2·H2O (112 mg, 0.4 mmol) and (H6-
4a)(CF3CO2)4 (170 mg, 0.2 mmol); yield 175 mg (0.18 mmol, 90%)
of a blue solid. MALDI-MS (TOF, positive ions): m/z = 631
{[Cu2(CF3CO2)(H2-4a)]–2H}+. UV/Vis (methanol): λ = 685 nm. IR
solid. MALDI MS (TOF, positive ions): m/z
=
621
[Ni2(CF3CO2)(4a)]+. UV/Vis (methanol): λ = 949, 583, 382 nm. IR
(KBr): ν = 3376 (m), 3316 (m), 2933 (w), 2894 (w), 2864 (w), 1689
˜
(s, CO), 1591 (m, CO), 1543 (s, CO) cm–1.
(KBr): ν = 3228 (m), 2969 (w), 2894 (w), 2819 (w), 1676 (s, CO),
˜
1545 (m, CO) cm–1.
[(Zn2(CF3CO2)2(4a))Zn(CF3CO2)2] (11): Salt (H6-4a)(CF3CO2)4
(850 mg, 1.0 mmol) was suspended in THF (30 mL) and 3.0 mL
of a 1  solution of diethylzinc in hexane (3.0 mmol) were added
dropwise. The resulting solution was stirred for 12 h at ambient
temperature. Subsequently, diethyl ether (50 mL) was added. A col-
orless solid precipitated which was collected by filtration and dried
in vacuo; yield 943 mg (0.91 mmol, 91%) of a colorless solid.
1H NMR (400.1 MHz, CD3CN): δ = 8.55 (m, 2 H, Ar-Hortho), 6.97
(m, 2 H, Ar-Hpara), 3.72 {s, 4 H, [C(O)CH2N]}, 3.09 (s, 8 H,
NCH2CH2NH2), 2.78 (m, 16 H, NCH2CH2NH2 and
NCH2CH2NH2) ppm. 13C NMR (100.6 MHz, CD3CN): δ = 174.0
[Cu2(CF3CO2)2(H2-4b)](CF3CO2)2 (6b): The complex was synthe-
sized from Cu(acac)2·H2O (112 mg, 0.4 mmol) and (H6-
4b)(CF3CO2)4 (160 mg, 0.2 mmol); yield 152 mg (0.16 mmol, 80%)
of a blue solid. Crystals suitable for an X-ray diffraction study were
obtained by slow diffusion of diethyl ether into a solution of the
complex in DMF. MALDI-MS (TOF, positive ions): m/z = 583
{[Cu2(CF3CO2)(H2-4b)]–2H}+. UV/Vis (methanol): λ = 670 nm. IR
(KBr): ν = 3299 (m), 3239 (m), 3172 (m), 3089 (w), 2965 (w), 2894
˜
(w), 1679 (s, CO), 1639 (s, CO) cm–1.
2
–
[Ni2(CF3CO2)4(H2-4a)] (7a): The complex was synthesized from
Ni(CH3CO2)2·4H2O (100 mg, 0.4 mmol) and (H6-4a)(CF3CO2)4
[NHC(O)], 161.9 (q, JCF = 35.7 Hz, CF3CO2 ), 139.1 (Ar-Cipso),
1
–
123.9, 123.8 (Ar-C), 117.7 (q, JCF = 291 Hz, CF3CO2 ), 61.0
(170 mg, 0.2 mmol); yield 167 mg (0.17 mmol, 85%) of a blue solid. [C(O)CH2N], 54.6 (NCH2CH2NH2), 38.1 (NCH2CH2NH2) ppm.
MALDI-MS (TOF, positive ions): m/z = 621 {[Ni2(CF3CO2)(H4-
MALDI-MS (TOF, positive ions): m/z = 635 [Zn2(CF3CO2)(4a)]+.
Only a dinuclar complex, which is apparently identical to 8 was
detected by mass spectrometry. The instability of 11 towards de-
4a)]–2H}+. UV/Vis (methanol): λ = 979, 588, 372 nm. IR (KBr): ν
˜
= 3367 (m), 3305 (m), 2968 (w), 1683 (s, CO), 1647 (s, CO) cm–1.
Eur. J. Inorg. Chem. 2010, 909–917
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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915

F. E. Hahn, H. Schröder, T. Pape, F. Hupka
FULL PAPER
composition to 8 was also observed when complex 11 was dissolved
in methanol. Dissolving of the trinuclear complex 11 (520 mg,
0.5 mmol) in methanol (10 mL) followed by addition of diethyl
ether (50 mL) leads to precipitation of 8 together with zinc trifluo-
roacetate as a non separable impurity. Crystals of [Zn(CF3CO2)-
(4a)](CF3CO2)·[Zn(4a)(MeOH)]-[Zn(CF3CO2)4] which were suit-
able for an X-ray diffraction study were obtained by slow diffusion
of diethyl ether into a solution of the unpurified reaction product
in methanol. For an X-ray diffraction study of [Zn(CF3CO2)-
(4a)](CF3CO2)·[Zn(4a)(MeOH)][Zn(CF3CO2)4] see Supporting In-
formation.
15.7631(5), b = 14.8340(5), c = 16.7906(5) Å, β = 91.8110(10)°, V
= 3924.2(2) Å3, 34074 measured reflections, 7633 unique reflections
(Rint = 0.0494), R = 0.0563, wR = 0.1444 for 5687 contributing
reflections [IՆ2σ(I)].
Crystal
Data
for
[Zn2(CF3CO2)(4a)](CF3CO2)·3MeOH
(8·3MeOH): C25H44N8F6O9Zn2, M = 845.46, monoclinic, P21/n, Z
= 4, a = 11.1232(11), b = 11.1663(8), c = 29.677(2) Å, β =
100.377(6)°, V = 3625.8(5) Å3, 20991 measured reflections, 6425
unique reflections (Rint = 0.0588), R = 0.0498, wR = 0.1247 for
4700 contributing reflections [IՆ2σ(I)].
Crystal Data for [Cu2(CF3CO2)(4a)](CF3CO2)·MeOH (9·MeOH):
X-ray Diffraction Studies: Diffraction data were collected at T =
153(2) K with a Bruker AXS APEX CCD diffractometer equipped
with a rotation anode using graphite-monochromated Mo-Kα radi-
¯
C23H36N8Cu2F6O7, M = 777.69, triclinic, P1, Z = 2, a =
11.3617(7), b = 11.6130(6), c = 13.2967(9) Å, α = 110.445(4), β =
103.036(4), γ = 96.414(4)°, V = 1566.3(2) Å3, 9081 measured reflec-
tions, 5261 unique reflections (Rint = 0.0550), R = 0.0888, wR =
0.2372 for 3663 contributing reflections [IՆ2σ(I)].
ation (λ
= 0.71073 Å) for 5a·MeOH, 6a·MeOH, 6b·2DMF,
(7a)(MeOH)2·0.5MeOH, 7b·2MeCN and (10)2·2MeOH·2Et2O and
with a Bruker AXS SMART CCD diffractometer equipped with a
rotation anode using Goebel-mirror monochromated Cu-Kα radia-
tion (λ = 1.54178 Å) for 8·3MeOH and 9·MeOH. Diffraction data
were collected over the full sphere and were corrected for absorp-
tion. The data reduction was performed with the Bruker
SMART[17] program package. Structures were solved with the
SHELXTL-97[18] package using the heavy-atom method and were
refined with SHELXL-97[19] against |F2| using first isotropic and
later anisotropic thermal parameters for all non-hydrogen atoms.
Hydrogen atoms were added to the structure models in calculated
positions.
Crystal Data for [(Ni2(CF3CO2)2(4a))2]·2MeOH·2Et2O [(10)2·
2MeOH·2Et2O]: C54H92N16F12Ni4O16, M = 1684.28, monoclinic,
P21/n, Z = 2, a = 14.3330(4), b = 15.7163(4), c = 15.8825(4) Å, β =
96.3460(10)°, V = 3555.8(2) Å3, 41385 measured reflections, 10353
unique reflections (Rint = 0.0496), R = 0.0397, wR = 0.0896 for
7679 contributing reflections [IՆ2σ(I)].
Supporting Information (see also the footnote on the first page of
this article): Structure data of (H6-4a)(CF3CO2)2·2MeOH and
[Zn(CF3CO2)(4a)](CF3CO2)·[Zn(4a)(MeOH)][Zn(CF3CO2)4].
CCDC-764055 (for 5a·MeOH), -746056 (for 6a·MeOH), -746057
(for 6b·2DMF), -746058 (for 7a(2MeOH)2·0.5MeOH), -746059 (for
7b·2MeCN), -746060 (for 8·3MeOH), -746062 (for 9·MeOH) and
-746057 (for (10)2·2MeOH·2Et2O) contain the supplemantary crys-
tallographic data for this paper. These data can be obtained free
of charge from The Cambridge Crystallographic Data Center via
www.ccdc.cam.ac.uk/data_request/cif.
Acknowledgments
This work was supported by the Deutsche Forschungsgemeinschaft
(DFG) (IRTG 1444) and the Fonds der Chemischen Industrie. We
thank Dr. Alexander Hepp and Dr. Klaus Bergander for measuring
the NMR spectra.
Crystal Data for [Zn2(CF3CO2)2(H2-4a)](CF3CO2)2·MeOH
¯
(5a·MeOH): C27H38N8F12O11Zn2, M = 1009.42, triclinic, P1, Z =
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U. P. Chaudhuri, L. R. Whiteaker, L. Yang, R. P. Houser, Dal-
ton Trans. 2006, 1902–1908.
2, a = 10.518(3), b = 12.369(3), c = 15.020(4) Å, α = 94.227(6),
β = 90.735(5), γ = 99.474(5)°, V = 1921.5(8) Å3, 19093 measured
reflections, 8819 unique reflections (Rint = 0.0546), R = 0.0534, wR
= 0.1062 for 5827 contributing reflections [IՆ2σ(I)].
Crystal Data for [Cu2(CF3CO2)2(H2-4a)](CF3CO2)2·MeOH
¯
(6a·MeOH): C27H38N8Cu2F12O11, M = 1005.73, triclinic, P1, Z =
2, a = 10.1222(3), b = 11.1517(4), c = 18.9396(6) Å, α =
80.7870(10), β = 77.1800(10), γ = 87.1450(10)°, V = 2057.49(12) Å3,
25602 measured reflections, 12927 unique reflections (Rint
0.0197), R = 0.0848, wR = 0.2577 for 10091 contributing reflections
[IՆ2σ(I)].
=
[3] O. Belda, C. Moberg, Coord. Chem. Rev. 2005, 249, 727–740.
[4] a) R. L. Chapman, R. S. Vagg, Inorg. Chim. Acta 1979, 33,
227–234; b) R. L. Chapman, F. S. Stephens, R. S. Vagg, Inorg.
Chim. Acta 1980, 43, 29–33.
Crystal Data for [Cu2(CF3CO2)2(H2-4b)](CF3CO2)2·2DMF
¯
(6b·2DMF): C28H48N10Cu2F12O12, M = 1071.84, triclinic, P1, Z =
1, a = 9.8653(8), b = 10.1077(8), c = 11.5686(9) Å, α = 82.1400(10),
β = 80.2760(10), γ = 69.9340(10)°, V = 1064.10(15) Å3, 12904 mea-
sured reflections, 6611 unique reflections (Rint = 0.0166), R =
0.0327, wR = 0.0883 for 5872 contributing reflections [IՆ2σ(I)].
[5] R. L. Chapman, F. S. Stephens, R. S. Vagg, Acta Crystallogr.,
Sect. B 1981, 37, 75–79.
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26, 3893–3903.
Crystal Data for [Ni2(CF3CO2)2(H2-4a)(MeOH)2](CF3CO2)2·
0.5MeOH (7a(MeOH)2·0.5MeOH): C28.5H44N8F12Ni2O12.5, M =
1044.14, triclinic, P1, Z = 2, a = 12.3714(7), b = 12.4745(7), c =
15.4866(9) Å, α = 69.6920(10), β = 71.2890(10), γ = 76.0320(10)°, V
= 2100.1(2) Å3, 20004 measured reflections, 9039 unique reflections
(Rint = 0.0391), R = 0.0634, wR = 0.1719 for 6546 contributing
reflections [IՆ2σ(I)].
[7] N. Niklas, S. Wolf, G. Liehr, C. E. Anson, A. K. Powell, R.
Alsfasser, Inorg. Chim. Acta 2001, 314, 126–132.
[8] S. Novokmet, F. W. Heinemann, A. Zahl, R. Alsfasser, Inorg.
Chem. 2005, 44, 4796–4805.
[9] a) T. E. Patten, M. M. Olmstead, C. Troeltzsch, Inorg. Chim.
Acta 2008, 361, 365–372; b) D. S. Marlin, D. Gonzáles Cab-
rera, D. A. Leigh, A. M. Z. Slawin, Angew. Chem. Int. Ed.
2006, 45, 77–83.
[10] a) A. M. Dittler-Klingemann, F. E. Hahn, Inorg. Chem. 1996,
35, 1996–1999; b) A. M. Dittler-Klingemann, C. Orvig, F. E.
¯
Crystal Data for [Ni2(CF3CO2)4(H2-4b)]·2MeCN (7b·2MeCN):
C26H40N10F12Ni2O10, M = 998.02, monoclinic, P21/c, Z = 4, a =
916
www.eurjic.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Received: November 25, 2009
Published Online: January 12, 2010
Eur. J. Inorg. Chem. 2010, 909–917
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
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