Dissection of different donor abilities within bis(pyrazolyl) pyridinylmethane transition metal complexes

Article abstract of DOI:10.1002/zaac.201300103

Using the bis(pyrazolyl)pyridinylmethane ligand α,α,α- bis(1-pyrazolyl)(2-pyridinyl)toluene {(ph)C(pz)₂(py)} for bioinorganic inspired coordination chemistry studies, we synthesised and structurally characterised three monofacial complexes [{(p

Full text of DOI:10.1002/zaac.201300103

ARTICLE
DOI: 10.1002/zaac.201300103
Dissection of Different Donor Abilities Within
Bis(pyrazolyl)pyridinylmethane Transition Metal Complexes
Alexander Hoffmann[a] and Sonja Herres-Pawlis*[a]
Dedicated to Professor Werner Uhl on the Occasion of His 60th Birthday
Keywords: N donor ligands; Iron; Cobalt; Copper; Zinc
Abstract. Using the bis(pyrazolyl)pyridinylmethane ligand
severe disorders between pyrazolyl and pyridinyl donor groups are
α,α,α-bis(1-pyrazolyl)(2-pyridinyl)toluene {(ph)C(pz)2(py)} for bio- observed such that bis(pyrazolyl) and (pyrazolyl)(pyridinyl) coordina-
inorganic inspired coordination chemistry studies, we synthesised tion modes are concomitantly found. The donor competition is dis-
and structurally characterised three monofacial complexes
sected by DFT calculation of the energy differences between the two
[{(ph)C(pz)2(py)}CoCl2] (C1), [{(ph)C(pz)2(py)}CuCl2] (C2), coordination modes and NBO analysis of the donor situation. The pyr-
[{(ph)C(pz)2(py)}ZnCl2] (C3) and the binuclear halogenido- azolyl units provide with more donor strength although pyridine is
bridged complexes [{(ph)C(pz)2(py)}2(μ-Cl)2Fe2Cl2] (C4) and considerably more basic.
[{(ph)C(pz)2(py)}2(μ-Br)2Cu2Br2] (C5). In four of these complexes,
In many complexes of tridentate pyrazolyl-containing li-
gands, the coordination by all three donors has been ob-
Introduction
N donors play a crucial role in bioinorganic chemistry since
served.[10–12] In further coordination studies, a more compli-
the majority of metalloproteins comprise active sites with histi-
cated picture arose since bidentate pyridinyl-pyrazolyl
dine coordination.[1] Decades of efforts have been directed
coordination was reported parallel to bis(pyrazolyl) coordina-
towards the sophisticated design of biomimetic facial coordi-
tion.[13–15] Substitution of donor groups and backbone changes
nating N donor ligands.[1,2] The important screws for ligand
the nucleophilicity of the pyridinyl and pyrazolyl groups.[16,17]
design are the variation of donor strength and steric encum-
With the apically substituted biomimetic bis(pyrazolyl)pyridin-
brance. Most prominent donor groups are imidazole, pyrazole
ylmethane
α,α,α-bis(1-pyrazolyl)(2-pyridinyl)toluene
li-
and pyridine due to their similarity to the imidazole in the
histidine residues in biologic systems.[1] Tuning of donor
strength is a subtle interplay of basicity and nucleophilicity
(e.g. through substitution) as well as of suited bite angles. Es-
pecially in the case of pyrazole vs. pyridine the relation is
complicated: regarding basicity, pyridine is three pKa units
more basic than pyrazole.[3] Thermochemical complex dissoci-
ation studies investigated the nucleophilicity of both donors
in carbonyl complexes and found that pyrazole is favored.[4]
Moreover, simple steric reasons make pyrazole as five-mem-
bered ring superior over pyridine in metal coordination. With
regard to π donor abilities, pyrazolyl is superior to pyridinyl
as well.[5] In general, the electronic structures of pyridinyl,
pyrazolyl or imidazolyl complexes differ strongly due to the
differences in σ and π donor abilities.[6–9]
gand[18] only three complexes are known until now: a bisfacial
octahedral iron complex,[19] a square-planar coordinated silver
complex (bis(chelate) coordination exclusively by pyrazolyl N
donors)[20] and an octahedral manganese carbonyl complex fa-
cially coordinated by all three N donors and three carb-
onyls.[21]
Here, we report on five new complexes incorporating the
biomimetic bis(pyrazolyl)pyridinylmethane α,α,α-bis(1-pyr-
azolyl)(2-pyridinyl)toluene with the transition metals iron, co-
balt, copper and zinc. Three of them exhibit interesting disor-
dered crystal structures. We have found that the pyridinyl and
the pyrazolyl moieties can easily replace each other. We pres-
ent a structural study of these complexes combined with theo-
retical analysis of the different coordination modes.
* Prof. Dr. S. Herres-Pawlis
Fax: +49-89-218077904
Results and Discussion
E-Mail: sonja.herres-pawlis@cup.uni-muenchen.de
[a] Department of Chemistry
The reaction of the ligand α,α,α-bis(1-pyrazolyl)(2-pyrid-
inyl)toluene (ph)C(pz)2(py)[18] with the corresponding transi-
tion metal salts in dry organic solvents leads to the formation
of the complexes. Single crystals for X-ray crystallography
analyses were obtained after diffusion of ethyl ether or pentane
Ludwig-Maximilians-Universität München
Butenandtstr. 5–13
81377 Munich, Germany
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201300103 or from the au-
thor.
1426
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2013, 639, (8-9), 1426–1432

Different Donor Abilities Within Bis(pyrazolyl)pyridinylmethane Metal Complexes
Figure 1. Molecular structure of C1 [{(ph)C(pz)2(py)}CoCl2], C2
[{(ph)C(pz)2(py)}CuCl2] and C3 [{(ph)C(pz)2(py)}ZnCl2] in the solid
state (Hydrogen atoms omitted for clarity).
In complexes C1–C3 the transition metal is fourfold coordi-
nated by two N donor atoms of the heteroscorpionate ligand
and the two chlorido ligands (Figure 1). In C1 and C3 the
coordination environment is a distorted tetrahedron and in C2
distorted square-planar.
Scheme 1. Synthesis of C1–C5.
Complexes C1–C3 possess a disorder between the N-donor
groups of the heteroscorpionate ligand which can be separately
refined in C2 and C3. Two coordination motifs are shown
into the complex solution or evaporation of the solvent within the crystal structure: the first coordination motif is the
and dissolution in a new solvent. We isolated the mono- coordination by the two pyrazolyl donors and the two chlorido
facial
complexes
C1
[{(ph)C(pz)2(py)}CoCl2],
C2 ligands to the transition metal (pyrazolyl-pyrazolyl coordina-
[{(ph)C(pz)2(py)}CuCl2] and C3 [{(ph)C(pz)2(py)}ZnCl2] tion in C2pzpz and C3pzpz) and the second motif is the coordi-
and the binuclear halogenido bridged complexes C4 nation by one pyridinyl donor and one pyrazolyl donor and
[{(ph)C(pz)2(py)}2(μ-Cl)2Fe2Cl2] and C5 [{(ph)C(pz)2(py)}2 the two chlorido ligands (pyridinyl-pyrazolyl coordination in
(μ-Br)2Cu2Br2] (Scheme 1), independent on the ratio of ligand C2pypz and C3pypz). For reasons of clarity, this disorder is not
to metal salt. Selected bond lengths and angles are collected shown in Figure 1 but it is analyzed in detail in the structural
in Table 1, and all relevant crystallographic data of these com- discussion (Table 1). A third possible coordination motif is the
plexes are listed in Table 6.
coordination of all three N donors and both chlorido ligands
Table 1. Selected bond lengths and angles of C1–C5 in crystals of C1 [{(ph)C(pz)2(py)}CoCl2], C2 [{(ph)C(pz)2(py)}CuCl2], C3
[{(ph)C(pz)2(py)}ZnCl2], C4 [{(ph)C(pz)2(py)}2(μ-Cl)2Fe2Cl2] and C5 [{(ph)C(pz)2(py)}2(μ-Br)2Cu2Br2].
C1
C2pzpz
C2pypz
C3pzpz
Bond lengths /Å
2.077(16)
C3pypz
C4
C5pzpz
C5pypz
N(2)–M
N(4)–M
N(5’)–M
X(1)–M
X(2)–M
X(1A)–M
2.027(3)
2.017(3)
1.958(8)
1.993(3)
2.113(2)
2.166(2)
2.087(12)
2.018(3)
1.993(3)
2.085(14)
2.229(1)
2.268(1)
2.046(2)
2.046(2)
2.02(2)
2.018(3)
1.85(3)
2.411(1)
2.372(1)
2.905(1)
2.208(1)
2.301(1)
2.229(1)
2.268(1)
2.219(1)
2.191(1)
2.219(1)
2.191(1)
2.368(1)
2.286(1)
2.498(1)
2.411(1)
2.372(1)
2.905(1)
Bond angles /°
N(2)–M–N(4)
N(4)–M–N(5’)
N(2)-M–(X1)
N(2)–M–(X1A)
N(2)–M–X(2)
N(4)–M–X(1)
N(4)–M–X(1A)
N(4)–M–X(2)
N(5’)–M–X(1)
N(5’)–M–X(1A)
N(5’)–M–X(2)
X(1)–M–X(2)
X(1)–M–X(1A)
X(2)–M–X(1A)
91.2(1)
87.3(3)
89.3(3)
89.1(4)
83.1(1)
84.1(4)
90.0(10)
173.1(4)
87.2(3)
92.6(4)
92.2(1)
94.2(1)
161.6(1)
83.8(4)
90.7(7)
90.0(10)
104.9(1)
103.0(4)
131.8(1)
90.2(1)
113.6(1)
90.4(1)
165.3(1)
95.4(1)
119.6(1)
108.4(1)
176.2(3)
159.4(1)
120.7(4)
108.5(1)
159.4(1)
108.5(1)
92.2(1)
94.2(1)
118.6(1)
91.1(1)
91.1(1)
94.3(4)
116.9(1)
116.9(1)
108.1(6)
161.6(1)
177.7(10)
92.2(10)
85.3(10)
92.7(1)
170.2(4)
93.4(1)
114.7(6)
115.1(1)
111.8(1)
0.86
93.4(1)
0.17
115.1(1)
0.86
114.5(1)
84.3(1)
99.3(1)
92.7(1)
87.3(1)
103.7(1)
87.3(1)
103.7(1)
[25]
τ4
0.21
0.90
[26]
τ5
0.56
0.19
0.26
C2, C3 and C5: Disorder in coordination of pyrazolyl vs. pyridinyl: C2: 63.5% C2pzpz, C3: 56.6% C3pzpz and C5 68.7% C5pzpz
www.zaac.wiley-vch.de
.
Z. Anorg. Allg. Chem. 2013, 1426–1432
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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A. Hoffmann, S. Herres-Pawlis
ARTICLE
(tris coordination) which has not been observed in these com- Table 2. Energetic difference between the pypz coordination motif of
the bidentate coordination with two pyrazolyl donors (Turbomole,
plexes. These three possible coordination motifs (see Figure 2)
BP86, def2-TZVP, Co2+ as quartet, Fe2+ as singlet and Cu2+ as doub-
were investigated with DFT analysis (BP86/def2-TZVP)[22–24]
let).
(vide infra).
Energy /kcal·mol–1
C1
C2
C3
–1.02
–0.44
–0.14
Table 3. Key geometric parameters of the two coordination motifs of
C1–C3 (Turbomole, BP86, def2-TZVP, Co2+ as quartet, Fe2+ as singlet
and Cu2+ as doublet).
Complex Bond lengths /Å, Angles /° CXpzpz
CXpypz
C1
C2
C3
Co–Npz
Co–Npy
Co–Cl
N–Co–N
Cu–Npz
Cu–Npy
Cu–Cl
N–Cu–N
Zn–Npz
Zn–Npy
Zn–Cl
2.022, 2.017 1.983
2.013
2.188, 2.201 2.197, 2.185
Figure 2. Possible coordination motifs of the ligand (ph)C(pz)2(py)
and MCl2.
89.8
81.3
2.069, 2.056 2.012
2.075
2.221, 2.226 2.221, 2.223
In the tetrahedral complexes C1 and C3 the M–N bond
lengths within one complex are equal whereas the M–Cl bond
lengths are different. The N donor bite angles amount to values
around 90° being significantly smaller than the ideal value of
109.5°. The X-M-X angles deviate to wider angles of 111–
115°. The deviation from ideal tetrahedral geometry can be
quantified using the structural parameter τ4 which indicates
with a value of zero a square-planar arrangement and with 1
85.5
86.4
2.144, 2.147 2.075
2.161
2.218, 2.214 2.213, 2.205
N–Zn–N
83.4
85.5
Both coordination modes are energetically very similar
an ideal tetrahedron.[25] In C1 and C3, τ4 is larger than 0.8, which can explain the tendency for disorder within the crystals
hence indicating only small deviation from the ideal tetrahedral of C2 and C3. Both isomers seem to exist concomitantly in
geometry. Following this quantification, C2 can be assigned solution and upon precipitation, they crystallize together.
in both forms as distorted square-planar complex with τ4 of
approximately 0.2. The angles between the donor atoms devi- with the experimental structure but for C2 and C3, too long
ate only slightly from the ideal 90°. Interestingly in C2pypz
bond lengths are predicted. Furthermore, DFT shows the dif-
the bite angle N-M-N is only 83.8(4) and the pyridine copper ferent donor situation in the pypz complexes C2pypz and
distance is longer than the pyrazolyle copper distance.
C3pypz since the M–Npy bonds lengths are significantly longer
For C1, the calculated Co–N bond lengths correspond well
,
In C1 to C3 we observe the above-described disorder be- than the M–Npz bond lengths. This tendency is found experi-
tween the pyrazolyl and the pyridinyl donor functions which mentally in C2pypz. The data set of C3pypz is not good enough
motivated us to a DFT study on the three possible coordination to contribute to this question. The bite angles are calculated to
motifs with this ligand for CoCl2, CuCl2 and ZnCl2.
Table 2 summarizes the energetic differences of the three mental structures.
coordination motifs (pzpz, pypz or tris) and Table 3 collects C4 [{(ph)C(pz)2(py)}2(μ-Cl)2Fe2Cl2]
be smaller than 90° which widely corresponds to the experi-
and
C5
the key geometric parameters of the calculated structures. Mul- [{(ph)C(pz)2(py)}2(μ-Br)2Cu2Br2] are dimeric species (Fig-
tiple attempts to obtain tris-coordinated facial complexes geo- ure 3). In both complexes each metal ion is fivefold coordi-
metries failed since the calculations ran into the pypz or pzpz nated: two coordination sites are occupied by two N donors
coordination. Hence, the discussion treats only the difference of the heteroscorpionate, further two by bridging halogenido
between these two coordination modes.
ligands and the last one by a terminal halogenido ligand. So
Figure 3. Molecular structure of C4 [{(ph)C(pz)2(py)}2(μ-Cl)2Fe2Cl2] (left) and C5 [{(ph)C(pz)2(py)}2(μ-Br)2Cu2Br2] (right) in the solid state.
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Different Donor Abilities Within Bis(pyrazolyl)pyridinylmethane Metal Complexes
Table 4. NBO charges (in e– units) and charge transfer energies (in kcal·mol–1) in the two isomers of C1–C3.
C1pzpz
C1pypz
C2pzpz
C2pypz
C3pzpz
C3pypz
NBO charges
Npy(coord)
–0.394
–0.413
–0.456
Npy
–0.406
–0.408
–0.411
Npz(coord)
–0.243 / –0.240
–0.246
–0.267 / –0.259
–0.269
–0.300 /–0.300
–0.316
Npz
M
–0.272
0.474
–0.272
0.584
–0.274
0.913
0.474
0.601
0.922
Cl
–0.427 / –0.426
–0.402 / –0.418
–0.464 / 0.470
–0.465 / –0.461
–0.590 / –0.598
–0.581 / –0.593
CT energies
Npz Ǟ M
Npy Ǟ M
45.8; 45.3
47.0
38.5
36.5; 37.6
43.1
32.2
70.4; 20.3
81.5
62.8
the coordination environment in C4 is a distorted trigonal bi-
pyramid (τ5 = 0.56) and in C5 a square pyramid (τ5 = 0.19 or
0.26).[26]
The planar M2X2 unit forms a rhomb with a crystallographic
inversion center. The rhomb is defined by the M–X–M angle
(C4: 84.3(1)° and C5: 92.8(1)°) and both M–X bond lengths
(C4: 2.368(1) and 2.497(1) Å and C5: 2.410(1) and
The NBO calculation shows that the Npy donor atoms pos-
sess a more negative charge than the Npz donor atoms indepen-
dent of coordinating a metal or not. Furthermore, it is note-
worthy that in general the charge of all these donor atoms does
not change much upon coordination. Only in the zinc com-
plexes C3pypz and C3pzpz, a difference between coordinated
and uncoordinated N donors is significant with the coordinated
ones being more negative. This goes along with the higher
positive charge of the metal ions, going from cobalt over cop-
per to zinc. The analysis of the charge transfer energies of the
isomers exhibits that the pyrazolyl units donate more strongly
to the metals.
2.903(1) Å). In the literature, few complexes with
a
M2(μ-X)2X2 core with iron[27–39] and copper[40–47] have been
reported. The bond lengths and angles of C4 agree very well
with the reported Fe2(μ-Cl)2Cl2 rhombs but the copper com-
plex C5 shows a difference: in our case the value for the longer
Cu–Br bond length is significantly larger than the reported
bond lengths (longest reported: 2.868(2)[41]) whereas the
shorter bond length is in agreement with the described bond
lengths.[40–47] The Fe···Fe distance in C4 with 3.609(1) Å is
also in agreement with the reported Fe···Fe distances for these
Fe2(μ-Cl)2Cl2 cores, whereas in C5 the Cu···Cu distance with
3.862(2) Å is significantly longer than the reported Cu···Cu
distances for the Cu2(μ-Br)2Br2 cores (3.61–3.73 Å). In the di-
nuclear complex C5 the magnetic moment was determined
using the Evans method[48,49] with μeff = 3.4μB. So there is no
hint of an antiferromagnetic interaction of both copper ions.
This is in accordance to the literature because of the long
Cu···Cu distance.[50] DFT calculations gave a triplet state
which is 27.4 kcal·mol–1 more stable than the corresponding
singlet state.
Since metal ions are Lewis acids with geometric preferences
and chelate effects, we regarded the NBO charges of the li-
gands donating to the smallest Lewis acid – a proton. Here,
the pyridinyl N atom again displays the most negative charge
independent of being protonated or not. This is in accordance
with the greater basicity of pyridine towards pyrazole.[3] Re-
markably, the charge characteristics of the diprotonated ligand
are most similar to the situation in the zinc complexes C3pypz
and C3pzpz
.
Conclusions
Using the tridentate bis(pyrazolyl)pyridinylmethane α,α,α-
bis(1-pyrazolyl)(2-pyridinyl)toluene (ph)C(pz)2(py) for coordi-
nation, we were able to structurally characterise five new com-
plexes. In three mononuclear complexes C1–C3 a remarkable
exchange of the pyrazolyl against the pyridinyl donor groups
is observed resulting in strong disorders. Pyridinyl is the more
For more detailed analysis of the donor situation in C1–C3,
we calculated the natural population analysis (NBO)[51] of both
isomers of these complexes (Table 4) using geometries ob-
tained with the BP86/def2-TZVP method.[22–24] The NBO
analysis yields the NBO charges and charge transfer energies
for the donation from the pyrazolyl/pyridinyl units to the
metal ions. For comparison with the donation of the ligand basic group but in terms of nucleophilicity, pyrazolyl donates
(ph)C(pz)2(py), we additionally calculated the NBO charges of
the different diprotonated forms, namely (ph)C(pzH)2(py) and
(ph)C(pzH)(pz)(pyH) (Table 5).
more strongly to the metals (shown by NBO analysis). This
donor competition is normally won by pyrazolyl, but here, af-
ter substitution of the apical carbon atom with a phenyl group,
the pyridinyl group gains higher donor ability and the donor
competition becomes more complicated again. In the dinuclear
complex C5, a similar disorder between the two different do-
nor groups is observed as well. Hence, we provide with further
pieces for the puzzle of donor competition steered by the sub-
stitution pattern within biomimetic N donor ligands. Further
studies will be directed towards bis(chelate) complexes.
Table 5. NBO charges of the diprotonated ligand (in e– units).
(ph)C(pzH)2(py)
(ph)C(pzH)(pz)(pyH)
–0.540
Npy(prot)
Npy
–0.458
Npz(prot)
Npz
–0.272; –0.278
–0.350
–0.269
Z. Anorg. Allg. Chem. 2013, 1426–1432
© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
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A. Hoffmann, S. Herres-Pawlis
ARTICLE
Experimental Section
General
and all non-hydrogen atoms refined anisotropically with full-matrix
least-squares based on F2 (SHELXL97).[54] Hydrogen atoms were de-
rived from difference Fourier maps and placed at idealized positions,
riding on their parent carbon atoms, with isotropic displacement pa-
rameters Uiso(H) = 1.2Ueq(C) and 1.5Ueq(C methyl). In C2 it was not
possible to model the disordered solvent molecules (1/2 THF and 1/2
acetonitrile) in an adequate manner, the data set was treated with the
SQUEEZE facility of PLATON.[55,56] In the complexes C2, C3 and
C5 the disorder is refined isotropically and in C1 the disorder is not
refined because of the minor quality of the data set. Full crystallo-
graphic data (excluding structure factors) for C1 to C5 have been de-
posited with the Cambridge Crystallographic Data Centre as supple-
mentary no. CCDC-923245 for C1, CCDC-923246 for C2, CCDC-
923247 for C3, CCDC-923248 for C4 and CCDC-923249 for C5.
Copies of the data can be obtained free of charge on application to
CCDC, 12 Union Road, Cambridge CB2 1EZ, UK (Fax: +44-1223-
336-033; E-mail: deposit@ccdc.cam.ac.uk).
The ligand synthesis was performed under argon by using standard
Schlenk techniques. Complexes were synthesized in a glove box under
nitrogen atmosphere.
Solvents were purified according to literature procedure and kept under
nitrogen.[52] All chemicals were used as purchased. The ligand α,α,α-
bis(1-pyrazoyl)(2-pyridinyl)toluene (ph)C(pz)2(py) was synthesized as
described in the literature.[18]
Physical Methods
Following spectrometers were used to record spectra. IR: FT-IR spec-
trometer IFS 28 from Bruker. Mass spectra in the ESI-MS (4.5 kV,
350 °C) were recorded with a Thermoquest Finnigan. Elemental analy-
sis: LECO-CHNS-932.
Computational Details
Quantum chemical calculations were performed using Turbomole[57]
with the BP86 functional[22,23] and the def2-TZVP basis set.[24] The
crystal structures of the isomers have been used as starting geometries.
Frequency calculations did not show imaginary values. NBO calcula-
tions[51] were accomplished using the program suite Gaussian 09.[58]
The magnetic susceptibility of the complex C5 was measured by the
Evans method.[48,49] The solvent was CD3CN and a Bruker Avance
500 was used.
X-ray Analyses
Crystal data for compounds C1 to C5 are presented in Table 1 and
Table 6. Data for these complexes were collected with a Xcalibur S
Synthesis of the Complexes
Diffractometer from Oxford, using the programs CRYSALIS (Oxford, C1: [{(ph)C(pz)2(py)}CoCl2]: A mixture of (ph)C(pz)2(py) (300 mg,
2008) and CRYSALIS RED (Oxford, 2008) and Mo-Kα radiation (λ = 1.0 mmol) in THF (5 mL) was added slowly to a solution of CoCl2
0.71073 Å) and a graphite monochromator. The structures were solved (65 mg, 0.25 mmol) in acetonitrile (5 mL). After stirring for one hour
by direct methods (SHELXS97)[53] and conventional Fourier methods and diffusion of pentane in the reaction solution blue crystals suitable
Table 6. Crystallographic data and parameters.
C1
C2
C3
C4
C5
Empirical formula
Form. Mass /g·mol–1
Crystal size /mm
T /K
C18H15Cl2CoN5
431.18
C36H30Cl4Cu2N10
871.58
C18H15Cl2ZnN5
437.62
C36H30Cl4Fe2N10
856.20
C36H30Br4Cu2N10
1049.42
0.06 ϫ 0.05 ϫ 0.03 0.12 ϫ 0.08 ϫ 0.07 0.15 ϫ 0.14 ϫ 0.13 0.22 ϫ 0.15 ϫ 0.06 0.11 ϫ 0.07 ϫ 0.02
173
173
173
173
173
Crystal system
Space group
a / Å
b / Å
c / Å
triclinic
P1
monoclinic
C2/c
17.639(1)
15.565(1)
15.376(1)
90
93.96(1)
90
4221.4(5)
4
triclinic
P1
triclinic
P1
triclinic
P1
¯
¯
¯
¯
9.743(1)
10.113(1)
10.542(1)
72.63(1)
74.72(1)
71.26(1)
922.5(1)
2
9.687(1)
10.137(1)
10.594(1)
72.70(1)
74.68(1)
71.33(1)
924.4(1)
2
8.875(1)
9.034(1)
11.700(1)
83.85(1)
80.70(1)
84.72(1)
917.7(1)
1
8.607(1)
10.291(1)
11.083(1)
91.19(1)
105.76(1)
106.07(1)
902.9(3)
1
α /°
β /°
γ /°
V /Å3
Z
ρcalcd. /g·cm–3
1.552
1.232
1.375
1.301
1.572
1.629
1.549
1.125
1.930
5.647
μ /mm–1
λ /Å
F(000)
0.71073
438
0.71073
1768
0.71073
444
0.71073
436
0.71073
514
Range in hkl
Reflect. coll.
Independ. refl.
Rint.
Ϯ11, Ϯ12, Ϯ12
10744
3419
0.0467
3419
Ϯ21, Ϯ18, Ϯ18
19345
3929
0.0575
3929
Ϯ11, Ϯ12, Ϯ12
8896
3442
0.0322
3442
Ϯ10, Ϯ10, Ϯ14
10840
3399
0.0283
3399
Ϯ10, Ϯ12, Ϯ13
7811
3346
0.0491
3346
Refl. obs.
No. parameters
R1 [I Ն 2σ(I)]
wR2 (all data)
Goodness-of-fit
Largest diff. peak, hole /e·Å–3
225
235
235
243
235
0.0452
0.1207
0.911
0.0370
0.0708
0.811
0.0349
0.0839
0.947
0.0264
0.0699
1.093
0.0318
0.0522
0.719
–0.629, 1.484
–0.334, 0.534
–0.384, 1.437
–0.349, 0.427
–0.408, 0.560
1430
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© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2013, 1426–1432

Different Donor Abilities Within Bis(pyrazolyl)pyridinylmethane Metal Complexes
for X-ray diffraction were obtained (yield: 70%). IR (KBr, ν˜ [cm–1]):
3144 vw (ν (CHarom)), 3107 w (ν (CHarom)), 1599 w, 1583 w, 1542
vw, 1509 w, 1491 w, 1469 w, 1461 w, 1450 m, 1437 m, 1405 m, 1384
m, 1319 s, 1311 s, 1250 w, 1239 m, 1222 m, 1207 m, 1191 m, 1180 971.0
m, 1166 w, 1103 m, 1087 m, 1073 m, 1065 s, 1050 w, 1028 w, 995 [C36H30N1079Br81Br263Cu2+], 967.0 (5) [C36H30N1079Br281Br63Cu2+],
m, 973 vw, 946 w, 924 w, 912 w, 902 m, 865 m, 844 w, 761 vs, 700
m, 677 vs, 658 w, 638 m, 617 m, 602 m, 512 vw, 500 vw, 421 vw.
ESI(+)-MS: Complex is insoluble. C18H15N5Cl2Co (431.18 g·mol–1),
C 50.5 (calcd. 50.2); H 3.6 (calcd. 3.6); N 16.1 (calcd. 16.2)%.
1094 m, 1068 m, 1047 w, 1025 vw, 995 w, 944 w, 924 w, 900 w,
894 w, 867 w, 754 vs, 701 m, 670 vw, 655 w, 641 w, 619 w,
604 w, 506 vw, 433 vw. ESI(+)-MS (CH3CN, m/z, (%)):
(6)
[C36H30N1079Br81Br263Cu65Cu+],
968.9
(8)
811.1
(6)
[C36H30N1081Br63Cu65Cu+],
809.1
(10)
[C36H30N1079Br63Cu2+], 807.1 (5) [C36H30N1079Br63Cu2+], 447.0 (25),
445.0 (100) [C18H15N5BrCu+], 443.0 (60). C36H30N10Br4Cu2
(1049.42 g·mol–1), C 41.2 (calcd. 41.2); H 2.9 (calcd. 2.8); N 13.4
(calcd. 13.3)%. The magnetic moment was determined using the Evans
method[48,49] with μeff = 3.4μB.
C2: [{(ph)C(pz)2(py)}CuCl2]: A mixture of (ph)C(pz)2(py) (300 mg,
1.0 mmol) in acetone (5 mL) was added slowly to a solution of
CuCl2·H2O (170 mg, 1 mmol) in acetonitrile (3 mL) and THF (3 mL).
After one day, green crystals were obtained (yield: 75%). IR (KBr, ν˜
[cm–1]): 3138 vw (ν (CHarom)), 3126 w (ν (CHarom)), 3076 w (ν
(CHarom)), 3068 vw (ν (CHarom)), 2973 w, 2927 vw, 2865 w, 1600 w,
1585 m, 1510 w, 1493 w, 1474 w, 1450 m, 1437 m, 1409 m, 1385 m,
1331 m, 1317 m, 1289 vw, 1221 m, 1202 m, 1182 m, 1162 w, 1103
m, 1092 m, 1068 m, 1025 w, 995 m, 973 vw, 944 w, 921 m, 902 m,
869 m, 759 vs, 700 m, 672 vw, 656 w, 645 w, 637 w, 618 w, 602 w,
498 vw, 433 vw. ESI(+)-MS (H2O, m/z, (%)): 399.0 (6)
Supporting Information (see footnote on the first page of this article):
DFT optimized coordinates of isomers of C1–C3, protonated ligand
and singlet and triplet states of C5.
Acknowledgments
Support by the Bundesministerium für Bildung und Forschung
(MoSGrid, 01IG09006) and the Deutsche Forschungsgemeinschaft
(DFG) (FOR 1405) is gratefully acknowledged. Calculation time is
gratefully acknowledged from the ARMINIUS Cluster at the PC2
Paderborn. We thank Prof. Thomas Klapötke for valuable support and
Prof. Peter Klüfers for fruitful discussions. Moreover, we thank Ines
dos Santos Vieira for collecting the X-ray data.
+
[C18H15N535ClCu+], 235.2 (20) [C15H12N3 +H], 234.2 (100)
[C15H12N3+]. C18H15N5Cl2Cu·1/2THF·1/2CH3CN (492.38 g·mol–1), C
51.0 (calcd. 51.2); H 4.2 (calcd. 4.2); N 15.6 (calcd. 15.6)%.
C3: [{(ph)C(pz)2(py)}ZnCl2]: A mixture of ZnCl2 (68 mg, 0.5 mmol)
in THF (8 mL) and acetonitrile (8 mL) was gradually added to a solu-
tion of (ph)C(pz)2(py) (300 mg, 1.0 mmol) in THF (8 mL). After stir-
ring for two hours, the solution was evaporated to dryness and the
residue was dissolved in THF (4 mL) and acetonitrile (4 mL). colorless
crystals were growth within some days (yield: 75%). IR (KBr, ν˜ [cm–
1]): 3144 w (ν (CHarom)), 3108 w (ν (CHarom)), 3086 vw (ν (CHarom)),
2938 vw, 2923 w, 2985 vw, 1718 vw, 1685 w, 1654 vw, 1637 vw,
1600 m, 1578 w, 1560 w, 1548 w, 1509 w, 1490 w, 1473 w, 1451 m,
1437 m, 1412 m, 1398 m, 1385 m, 1324 m, 1259 w, 1226 w, 1217 w,
1207 m, 1180 w, 1102 m, 1087 m, 1074 m, 1067 m, 1045 w, 1027 w,
995 w, 925 w, 912 vw, 902 w, 865 m, 761 vs, 698 m, 657 w, 638 m,
616 w, 604 w, 500 vw, 420 vw. ESI(+)-MS (CH3CN, m/z, (%)): 365.2
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Received: February 20, 2013
Published Online: April 9, 2013
1432
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© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Z. Anorg. Allg. Chem. 2013, 1426–1432