Modified bipyridines: 5,5'-Diamino-2,2'-bipyridine metal complexes assembled into multidimensional networks via hydrogen bonding and π-π stacking interactions

Article abstract of DOI:10.1002/(sici)1099-0682(199909)1999:9<1507::aid-ejic1507>3.0.co;2-i

A new synthetic route for the synthesis of 5,5'-diamino-2,2-bipyridine (5) based on the coupling of 2-chloro-5-aminopyridine in the presence of NiCl₂ x 6 H₂O/PPh₃/Zn in dimethylformamide is described The reactions of the p

Full text of DOI:10.1002/(sici)1099-0682(199909)1999:9<1507::aid-ejic1507>3.0.co;2-i

FULL PAPER
Modified Bipyridines: 5,5Ј-Diamino-2,2Ј-bipyridine Metal Complexes
Assembled into Multidimensional Networks via Hydrogen Bonding
and π–π Stacking Interactions
[
a]
[a]
[a]
[a]
[b]
Christoph Janiak,* Stephan Deblon, He-Ping Wu, Mario J. Kolm, Peter Klüfers,*
[b]
[b]
Holger Piotrowski, and Peter Mayer
Keywords: 2,2Ј-Bipyridines / Chelate complexes / Hydrogen bonding / π–π stacking / Crystal structure
A new synthetic route for the synthesis of 5,5Ј-diamino-2,2-
bipyridine (5) based on the coupling of 2-chloro-5-
aminopyridine in the presence of NiCl × 6 H O/PPh /Zn in
2 2 3
NMR including 113Cd-NMR, IR, and for the iron complex
57
Fe-Mößbauer spectroscopy. The structure of eight of the
compounds was elucidated by X-ray crystallography. All of
dimethylformamide is described. The reactions of the these metal complexes show bipyridine–metal
potentially ambidentate ligand 5 with salts of the transition coordination. The amino functionality was never involved in
metals Mn, Fe, Ni, Cu, Zn, Ag, and Cd gave a variety of 13 metal coordination. The intermolecular arrangement is
a
metal–ligand complexes depending on the anion, the
crystallization conditions and the metal-to-ligand ratio. The
complexes obtained were characterized by thermal analyses,
dictated by hydrogen bonding from the amino functionality
and by π–π stacking of the bipyridine rings.
Introduction
Metal complexes of chelating 2,2Ј-bipyridine (bipy, 1)
and secondary terminal or chelating amines are of constant
and general interest in metal-coordination chemistry.[ We
have recently engaged into a program to study the coordi-
nation behavior of modified 2,2Ј-bipyridine ligands such as
1]
[
2]
2
,2Ј-dimethyl-4,4Ј-bipyrimidine (2), 5,5Ј-dicyano-2,2Ј-bi-
[
3]
[4]
pyridine (3), 2,2Ј-bi-1,6-naphthyridine (4), and modi-
fied tris(pyrazolyl)borate ligands. As part of this program
[5]
we report here the coordinating properties of ambidentate
5
,5Ј-diamino-2,2Ј-bipyridine (5). The idea behind the use
of such ambidentate ligands is to have tetrahedral (6) or
octahedral building blocks (7) for supramolecular assem-
blies based on the chelation of two or three ligands, respec-
tively with an appropriate metal center. The intermolecular
connectivity should then be controlled through an
is a promising path in the search for stable microporous
metal-organic networks that exhibit reversible guest ex-
change and possibly selective catalytic activity.[
NH Ǟmetal coordination or through hydrogen bond-
2
11]
[
6][7]
ing.
The amino group on the aromatic ring is a good
candidate for hydrogen bonding as has been exploited in
the self-assembly of supramolecular entities with 2,4,6-tria-
minopyrimidine units, for example.[ The related ligand
8]
Results and Discussion
Ligand Synthesis
2
,2Ј-bipyridine-5,5Ј-dicarboxylate forms tris(chelate) com-
[9]
plexes which are then connected by hydrogen bonding.
Rigid bridging ligands have recently gained considerable
interest in the synthesis of (rectangular) two-dimensional
The synthesis of 5 has been achieved according to a route
[12]
suggested by Whittle (Scheme 1):
5,5Ј-Dimethyl-2,2Ј-bi-
[
10]
network structures.
The generation of such frameworks
pyridine (9) is obtained in medium yield by a Raney nickel
catalyzed coupling reaction from β-picoline (8).[
13][14]
Oxi-
[
[
a]
b]
dation with KMnO4 and esterification of the acid then
yields the 5,5Ј-diester 10.[ Hydrazinolysis of the ester
group and hydrazine-azide transformation gives the acyl az-
ide 11. In a Curtius rearrangement this acyl azide is con-
verted by pyrolysis to the isocyanate (RϪNϭCϭO) from
which in the presence of ethanol the dicarbamate 12 is de-
rived. Alkaline hydrolysis and sublimation leads to the final
Institut für Anorganische und Analytische Chemie, Universität
Freiburg,
15]
Albertstraße 21, D-79104 Freiburg, Germany
E-mail: janiak@uni-freiburg.de
Institut für Anorganische Chemie, Universität Karlsruhe,
Kaiserstraße 12, D-76131 Karlsruhe, Germany
Supporting Information for this article is available on the
WWW under http://www.wiley-vch.de/home/eurjic or from the
author.
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

WILEY-VCH Verlag GmbH, D-69451 Weinheim, 1999
1434Ϫ1948/99/0909Ϫ1507 $ 17.50ϩ.50/0
1507

C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
FULL PAPER
to give the NiCRAL was unsuccesful. The necessary excess
of NaH apparently deprotonates the amino function of the
pyridine, which then coordinates to the nickel center so that
the reaction is slowed down considerably. After 5 d under
reaction conditions, the starting compound was still present
and only traces of 5 were found. This is remarkable, since
under the same conditions 2-amino-3-chloropyridine is cou-
pled to the 2,2Ј-diamino-3,3Ј-bipyridine in 44% yield in 17
h.[17]
The use of zinc powder as a reducing agent for the NiC-
RAL was eventually successful: A solution of nickel(II)
chloride hexahydrate and triphenylphosphane in DMF was
reduced with zinc and was subsequently treated with a stoi-
chiometric amount of 5-amino-2-halopyridine. No pyridine
compound could be detected anymore after 2Ϫ2.5 h and
workup yielded the coupling product 5 in over 60% yield
(
Scheme 2). The starting compound for the coupling reac-
tion, the amino-substituted 2-halopyridine 13b was ob-
tained from the commercially available 2-chloro-5-nitro-
pyridine (13a).[
20]
product 5 in an overall yield of 38% based on 5,5Ј-dimethyl-
2
,2Ј-bipyridine.
Scheme 2. Synthesis of 5 based on an NiCRALϪcatalyzed cou-
pling of 5-amino-2-chloropyridine (13b)
Syntheses of Metal Complexes of 5
Different methods were used for the syntheses of metal
complexes of 5. An overview of the prepared metal com-
pounds is provided in Scheme 3.
In the case of the manganese complexes [Mn(5) ]Cl (14)
3
2
Scheme 1. Synthesis of 5 starting from 3-aminopyridine (8)
and [Mn(N ) (5) ] (15) it was sufficient to combine the re-
3
2
2
In order to shorten the synthesis of 5 and to improve the actands in solution and let them stand for some time. For
5
2ϩ
yield, we also tried a new method, namely the coupling of the d -high-spin Mn ion ligand substitution results only
5
-amino-2-chloropyridine (13). It was reported in the litera- in a small gain of energy because of the theoretically zero
ture that the coupling of haloaryl or halopyridine com- ligand field stabilization energy (LFSE). Hence, the thermo-
pounds in the presence of a catalytic system consisting of dynamic driving force for the formation of the manganese
NiCl ϫ 6 H O/L/reducing agent could lead to the forma- chelate complexes from the hexaaquametal ions is small
2
2
tion of bipyridine and biaryl derivatives. Such nickel-con- and the reaction proceeds much slower than for iron, nickel
taining complex-reducing agents are generally abbreviated and copper which have larger LFSE contributions.[21]
as NiCRALs, L representing PPh or 2,2Ј-bipyridine. Re-
Heating an aqueous suspension or an ethanolic solution
3
[16]
ducing agents can be zinc or a mixture of sodium hydride of 5 with a solution of the metal salt in water gave upon
and sodium tert-butoxide.[
17][18]
Zerovalent nickel com- cooling the tris(5,5Ј-diamino-2,2Ј-bipyridine)metal com-
plexes for the coupling of aryl halides were initially intro- plexes [M(5)3]2 of iron as the sulfate (16), nickel as the
ϩ
duced by Semmelhack and co-workers.[
19]
chloride (17), zinc as the nitrate (22), and cadmium as the
For the coupling of 5-amino-2-chloropyridine the use of chloride (26). Furthermore, the mono(5,5Ј-diamino-2,2Ј-bi-
sodium hydride as a reducing agent for the nickel complex pyridine)diaqua(µ-sulfato)copper compound 19 and a
1508
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
FULL PAPER
Scheme 3. The metal complexes of 5,5Ј-diamino-2,2Ј-bipyridine (5)
mono(5,5Ј-diamino-2,2Ј-bipyridine)silver derivative (see 23) mixing the reactands NiCl , 5, and KSCN and adding
2
was obtained by such a hydrothermal reaction. Also concentrated ammonia, so that the rather stable amminen-
Zn(NO ) (5)] (21) and [Cd(µ-Cl) (5)] (25) react with two ickel complex [Ni(NH3)6]2 is formed. In addition to the
ϩ
[
3 2 2
equivalents of 5 under reflux to form the homoleptic tris- synthetic procedures described in the Experimental Section,
(
chelate) complexes [Zn(5) ](NO ) (22) and [Cd(5) ]Cl2 the reactions were carried out with different concentrations
3 3 2 3
(
26), respectively. This observation agrees with the com- and different ratios of ligand to metal salt (varied in a wide
[22]
plexation behavior found for 2,2Ј-bipyridine.
range between 1:1 and 5:1). In all cases the 3:1 ligand/metal
A different synthetic route was chosen for complexes complexes were obtained, though. The deep-red iron com-
where the coordination sphere was not completely con- plex 16 was formed even in the case of a hundred-fold metal
structed by the diaminobipyridine chelate ligand 5. Such excess. The special stability of iron(II) complexes with 2,2Ј-
was the case for the compounds [CuCl (5)] (20), [Cd(µ- bipyridine is well known[ so that the unsubstituted bi-
24]
2
Cl) (5)] (24), and the presumable silver complex pyridine is applied as a test reagent for iron(II).
2
[
Ag(NO )(5)] (23). Here the synthesis was carried out at
All of the above metal complexes are insoluble in ali-
3
room temperature mostly by overlayering the aqueous phatic and aromatic solvents and in acetonitrile. The heter-
metal salt solution with an ethanolic solution of 5. To slow oleptic silver and cadmium complexes 23 and 25 are little
down the diffusion of both solvents a layer of ethyl acetate water- but easily DMSO-soluble. The heteroleptic Cu2
was brought in between the water and the ethanol phase. complexes 19 and 20 show a good solubility in water, but
In three cases it could be shown that the above heteroleptic they do not dissolve in alcohol or THF. The homoleptic
complexes may be viewed as thermodynamically unstable compounds 14 (Mn), 22 (Zn), and 26 (Cd) dissolve well
intermediates along the reaction coordinate to the homo- in hot water and DMSO, the tris(chelate)iron and -nickel
leptic compounds. The 1:1 ligand/metal complexes 21 and complexes 16 and 17 are well water-soluble but little in
ϩ
2
5 react with two equivalents of 5 under reflux to the DMSO. Many of the crystalline metal complexes with 5
thermodynamically apparently more stable tris(chelate) incorporate water of crystallization which is easily lost upon
complexes [Zn(5) ](NO ) (22) and [Cd(5) ]Cl2 (26), drying in air, so that the crystals have to be stored in water.
3
3 2
3
respectively. A 1:1 ligand/silver complex (as 23) is initially The silver complexes 23 and 24 are light-sensitive and have
obtained from the reaction of two equivalents of 5 with to be stored in the dark.
ϩ
one equivalent of Ag . This complex dissolves in concen-
An attempt was made to use the homoleptic tris(chelate)
trated aqueous ammonia and upon slow evaporation pro- complexes as building blocks in the reaction with silver ni-
duces the 2:1 ligand/metal complex [Ag(5) ]NO . Such a trate and to achieve the coordination through the amino
2
3
recrystallization involves formation of the intermediate function (to the silver atom) to give a heterobimetallic coor-
ϩ
[
Ag(NH ) ] complex and slow ligand exchange of the dination polymer. However, a simple ligand exchange was
3 2
[23]
stronger, yet more volatile ammine ligand with 5.
A
observed when the zinc complex 22 was used (Equation 1)
similar ligand exchange was used in the synthesis of the and a redox reaction occurred when the iron complex 16
complex [Ni(5) ](SCN) (18) which was obtained from was employed (Equation 2).
3
2
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
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C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
FULL PAPER
1
Table 2. H-NMR data of diamagnetic metal complexes of 5
Compound
Solvent
H3, H3Ј H4, H4Ј H6, H6Ј
Thermal Analyses
Free ligand 5
[D
6
6
6
6
]DMSO
]DMSO
]DMSO
]DMSO
7.92
7.92
7.91
7.92
7.90
8.08
8.43
7.99
6.95
7.15
7.12
7.14
7.09
7.19
7.84
7.28
7.84
7.91
7.90
7.98
7.88
7.08
7.79
6.85
[
[
[
Ag(NO
3
)(5)] (23) [D
Some complexes were studied by thermogravimetry (TG)
and differential scanning calorimetry (DSC) to gain infor-
mation on the amount of the incorporated crystal water, [Cd(5) ]Cl (26)
the temperature of water loss and other phase transitions.
The TG data on the water loss show good agreement with
values from NMR experiments (see Table 1) and fit the el-
emental analyses data. For 16 and 17 the water content
from the X-ray structural analyses is different. This may
indicate a varying water content for each single crystal.
After the loss of solvent water, the manganese complex
Ag(5)
2
]NO
3
(24)
[D
[D
CdCl
2
(5)] (25)
3
2
[D ]DMSO
6
[
Zn(5)
3
](NO
3
)
2
(22) [D
6
]DMSO
D
2
O
[Fe(5)
3
]SO (16)
4
D
2
O
4
- and 6-position experience a low-field shift compared to
signals in DMSO. The significant high-field shift of
.8Ϫ1 ppm of the signal of the proton in 6-position or α to
0
1
4 looses a ligand molecule at 290°C and possibly forms a
the metal center in 22/DMSO and 16/D O versus the silver
and cadmium complexes is due to the smaller ionic radii of
the zinc and iron metal centers. This improves the diamag-
2
neutral complex of composition [MnCl (5) ], which in turn
2
2
shows another phase transition at 361°C. Investigations on
solvated tris(2,2Ј-bipyridine)iron complexes have shown
that upon heating the loss of water of crystallization is fol-
lowed by sequential loss of ligands.[
netic interaction of the metal center with the ring cur-
rent.[22][27]
25]
The trends in the shifts in carbon-13 spectroscopy are
less straightforward. The signals of the carbon atoms 2, 3,
and 6 show only little chemical-shift difference to those of
the free ligand (Ϫ0.5 to ϩ0.8 ppm), the C4 signal experi-
NMR Spectroscopy
Nuclear magnetic resonance spectroscopy is a valuable ences a slight down-field shift (1 to 7 ppm) and the C5 sig-
tool to judge the electronic effects in ligands, including bi- nal an up-field shift (2.8 to 4.2 ppm). These trends stem
[
26]
10
pyridinemetal chelate complexes.
Usually, the d ions from two superimposing effects: The negative inductive ef-
ϩ
2ϩ
Ag and Cd only cause a small down-field shift of the fect of the coordinated metal ion leads in 2- and 6- (ortho)
proton signals with respect to those of the free ligand (∆δ ഠ position to the nitrogen atom to a down-field shift and to
0
.0Ϫ0.2 ppm). A comparison of the chemical shift data for a lesser extent also in the 4- (para) position. The interaction
5
and 22؊26 in Table 2 confirms this statement. The small of the paired metal d electrons with the diamagnetic ring
shift is due to the weak Lewis acidity and the small diamag- current, on the other hand, enhances the shielding and
netic interaction of the ring current with the relatively large consequently induces an upfield shift, which weakens with
[
27]
This is different for zinc and iron complexes. increasing distance from the metal center.[27][28]
cations.
Since the iron compound 16 was not soluble enough in
DMSO, it had to be measured in D O and the zinc complex help of 1 Cd-NMR-spectroscopy. The Cd ion has a rather
The ligand effect on a metal center was studied with the
13
II
2
2
2 was investigated in both solvents to allow comparison high relaxation time of 0.1Ϫ50 s. Labile complexes which
between iron and silver complexes, and the free ligand. experience rapid ligand exchange, including aqua ligands,
A comparison between the two different solvents for 22 then give a broad time-averaged signal. In the building
shows the effect of hydrogen bonding from water to the block [Cd(µ-Cl) (5)] of the heteroleptic complex 25, the co-
2
amino functions. This decreases the electron-donating ordination sphere can be concluded by aqua ligands so that
(
positive) inductive effect of the amino function to the het- the species [CdCl (5)(H O)] and [CdCl (5)(H O) ] also exist
2 2 2 2 2
erocycle so that especially the signals of the protons in the in solution with a rapid interchange among them.[
29][30]
Table 1. Thermogravimetic data on the crystal water content in 14, 16, and 17
Compound
Temperature
for H O loss
°C]
Mass loss
[mass%]
∆H
Water content [1/formula unit]
2
[
[kJ/g]
from TG
from NMR
from X-ray
[
[
[
Mn(5)
Fe(5) ]SO
Ni(5) ]Cl
3
]Cl
4
2
ϫ 6 H
ϫ 6 H
ϫ 6 H
2
O (14)
101Ϫ150
162Ϫ166
145Ϫ168
14.3
14.1
12.3
34.6
59.9
51.6
6.3
6.5
5.6
6.5
Ϫ
9.0
2.5
[
a]
3
2
O (16)
O (17)
Ϫ
3
2
2
6.0
[
a]
6
Due to the low solubility in [D ]DMSO the water content could not be verified by NMR.
1510
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
FULL PAPER
Hence, the signal for 25 was very broad and could not be has been elucidated with the 2- and 3-aminopyridine li-
clearly assigned. Whereas the tris(chelate) complex 26 gave gand.[
42][43]
The in-plane ring-stretch vibrations of 5 are
Ϫ1 [44]
a rather narrow singlet, which is indicative of the stable na- found at 1568, 1478 and 656 cm
.
The first two show
ure of [Cd(5)3]2 in solution. The chemical shift of δ ϭ 253 in all metal complexes the aforementioned hypsochromic
ϩ
Ϫ1
Ϫ1
for 26 [versus 2  Cd(ClO ) as a standard] falls right in the shift to 1579Ϫ1590 cm and 1486Ϫ1497 cm , respec-
range observed for other tris(bipyridine) and tris(phen- tively. The band at 656 cm either remains almost un-
4
2
Ϫ1
anthroline) complexes: [Cd(bipy) ](ClO ) (δ ϭ 243), shifted (in 15, 16, 17, 18, 22, 24, and 25) or is split into two
3
4 2
[
Cd(4,4Ј-Me bipy) ](ClO ) (δ ϭ 254), and [Cd(phen)3]- bands (as in 14, 19, 23, and 26). Similarly, the correspond-
2 3 4 2
[40][41]
ClO ) (δ ϭ 254 ppm) [all against 0.1  Cd(ClO ) solu- ing band in [Mn(bipy) ](ClO ) is split.
tion].
The expla-
4
2
4 2
3
4 2
[
29]
nation is sought in a substantial twist (over 10°) of the pyri-
dine ring planes around the connecting C2ϪC2Ј bond away
from the almost coplanar to a twisted cis configuration
Mößbauer Spectroscopy
(
27).
The iron complex 16 is an exception with respect to its
thermodynamic stability in the series of the analogous
ϩ
[
M(5)3]2 derivatives. It forms directly even at high metal
6
excess. A possible explanation is the 3d low-spin configura-
II
tion of the Fe ion which possesses a maximal ligand field
stabilization energy.[ Some bipyridineiron(II) complexes
31]
[32][33]
are known, e.g. [Fe(bipy) ](BF ) ϫ 2 H O
or
which exhibit a thermally in- dine pair are always twisted (see below).
duced low-spin to high-spin crossover. Such a spin cross- ture analysis of [Mn(bipy) ](ClO ) confirmed the substan-
To the extent of a few degrees the ring planes in a bipyri-
3
4 2
2
[34]
[45]
[
Fe(3,3Ј-Me -bipy) ](ClO )
An X-ray struc-
2
3
4 2
3
4 2
1
over changes the spin state from singlet- A to quintuplet- tial twist, the dihedral angles between each pair of pyridine
1
g
5
T2g and as a consequence leads to an increase in ligandϪ rings in all three bipyridine ligands lay between 13 and
metal bond length.[ Mößbauer spectroscopy allows to 25°.
35]
[46]
discern the spin state of the iron complex. For [Fe(5) ]SO4
The structures collected here do not reveal a substantial
3
(
16) in the solid state a pronounced doublet with an isomer twist in any case. The dihydral angles between the pyridine
shift δ(α-Fe) ϭ 0.30 mm/s (at 293 K) and a half-width Γ of ring planes were 9.7° in 15, 5.3, 5.7, and 11.3° in 18, 3.3°
0
0
.25 mm/s was found. The quadrupole splitting ∆EQ was in 19, 2.3° in 20, 5.2, 8.9, and 9.1° in 22, and 0.1° in 25.
.27 mm/s. These values are typical for tris(2,2Ј-bipyridine) This finding coincides with the non-splitting of the band at
Ϫ1
complexes of iron in the low-spin state. The isomer shifts around 656 cm
but does not agree with the splitting
measured, for example, for [Fe(bipy) ](ClO ) , [Fe(bi- found for 19. Hence, the IR analysis with respect to a
3
4 2
py) ]Cl , and [Fe(bipy) ]SO are 0.30, 0.33, and 0.24 mm/ twisted configuration should be applied with caution.
3
2
3
4
[
25,33,36]
s, respectively.
The small quadrupole splitting in 16
From aqueous solutions the ligand 5 crystallizes as the
indicates at the most a weak distortion from the octahedral monohydrate. The IR spectrum of 5 ϫ H O then shows two
2
Ϫ1
FeϪN coordination geometry. The DSC data for 16 ex- sharp bands at 3425 and 3340 cm , which are assigned to
6
clude the existence of a thermally induced spin transition the symmetric and asymmetric NH stretch. Three ad-
Ϫ1
up to the decomposition temperature of 350°C, because no ditional and broader bands at 3376, 3315, and 3205 cm
reversible phase transition could be observed.[
5][37]
Another are due to the formation of amino hydrogen bonds to the
indication along the same lines is the deep-red color of 16 water oxygen atom. The NH deformation is found at 1632
1
1
Ϫ1
which stems from the A Ǟ T d-d transition. Upon heat- cm . In all metal complexes the position of this bending
1
g
1g
ing, this color does not fade as would be expected from a vibration remains rather unchanged, different to what
spin crossover, because the smaller d-d splitting in the high- would be expected in case of aminoϪmetal com-
spin state shifts the absorption from the visible into the in- plexation.[
42]
[
5][38]
frared regime.
Both negative indicators for a spin
crossover behavior precluded
Mößbauer study.
a
temperature-variable
X-ray Structural Studies
Generally, all of the metal complexes of 5 which are
structurally elucidated here show a bipyridineϪmetal coor-
dination of the potentially ambidentate diaminobipyridine
Infrared Spectroscopy
Metal complexes with 2,2Ј-bipyridine ligands were the ligand. The amino functionality was never involved in metal
subject of intense IR-spectroscopical investigations.[
39Ϫ41]
coordination, yet, could play a substantial role in hydrogen
All bands are now clearly assigned. Some of the many ring bonding (see below). Specific distances and angles and
vibrations are sensitive to metal coordination and experi- some figures for the hydrogen bonding networks which are
ence an hypsochromic shift (to higher wavenumbers or en- not given here, can be found in the supporting information.
ergy) of 10 to 20 wavenumbers.[ The influence of the me- The specific structures are described in some more detail in
tal coordination on the vibrations of the amino function the following.
40]
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
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C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
FULL PAPER
[
Mn(N ) (5) ] (15)
3 2 2
Figure 1 illustrates the structure of this molecular com-
plex. The two azide ligands are cis-coordinated, terminally
bound and do not bridge between metal centers. The bond-
ing mode is not unusual for coordinated azides.[ The
pseudooctahedral structure of 15 is similar to cis-
47]
[48]
[
Mn(NCS) (bipy) ].
The MϪN(bipy) bond lengths trans
2
2
to the azide (or NCS) ligand show some lengthening. The
crystal structure is stabilized by stacking interactions in-
volving bipyridine ligands of adjacent molecules (πϪπ con-
˚
tacts down to 3.2 A). Intermolecular hydrogen bonding
from the amino functions to the N3 atom of the azide li-
ances [A] and angles [°]: MnϪN1 2.211(1), MnϪN31 2.265(1), gand is observed.
3 2 2
Figure 1. Molecular structure of [Mn(N ) (5) ] (15); selected dis-
˚
MnϪN32 2.286(1), N1ϪN2 1.171(2), N2ϪN3 1.168(2);
N1ϪMnϪN1#2 86.58(8), N1ϪMnϪN31#2 113.66(4), N1ϪMnϪ
N31 89.19(4), N31ϪMnϪN31#2 149.14(5), N1ϪMnϪN32
[
Fe(5) ]SO ؋ 9 H O (16)
3 4 2
The tris(chelate) structure (cf. Figure 3) of the [Fe(5) ]2
ϩ
1
7
1
54.51(5), N1ϪMnϪN32#2 86.07(5), N31#2ϪMnϪN32#2
1.61(4), N31ϪMnϪN32#2 90.61(4), N32ϪMnϪN32#2
10.09(6), N1ϪN2ϪN3 178.1(1) (symmetry equivalent position
2 ϭ 0.5 Ϫ x, y, Ϫz)
3
moiety is unremarkable (Table 3). Recent examples of
2
ϩ
[
[
Fe(bipy)3]
complexes
include
,
the
counterions
#
Ϫ [49]
2Ϫ [50]
2Ϫ [51]
Fe(NO) Cl ] ,
[Fe OCl ]
[Fe (ox) ]
,
and
2
2
2
6
2
3
2
ϩ
2Ϫ
Ϫ
Figure 2. Layer arrangement of the [M(5)
structures of (a, top) [Fe(5) ]SO ϫ 9 H
3
]
cations and the anions (SO
4
or Cl ) together with the water of crystallization in the
ϫ 2.5 H O (17); view along a (a) and b (b)
3
4
2
O (16) and (b, bottom) [Ni(5)
3
]Cl
2
2
1512
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
FULL PAPER
MC(ox) ]2
Ϫ [52][53]
,
(ox ϭ oxalate, M ϭ Ag, Na, Li). We
[
3
just note that 16 is constructed from alternating layers of
the tris(chelate) cations and layers of the sulfate anions to-
gether with the water of crystallization (Figure 2a). The in-
teraction between the layers occurs through hydrogen bond-
ing from the amino group to the oxygen centers.
[
Ni(5) ]Cl ؋ 2.5 H O (17) and [Ni(5) ](SCN) (18)
3 2 2 3 2
The tris(chelate) structure around the nickel centers (Fig-
ure 3, Table 3) is common in a sizable number of tris(bipyri-
dine)metal complexes which are described in the literature.
[
53]
Recent examples are [Ni(bipy) ][Mn (ox) ],
[Ni(bipy)3]-
3
2
3
[
54]
[55]
NaAl(ox)3],
[Ni(bipy) ][Ni(CN) ] ϫ bipy ϫ 6 H O,
3
4
2
[56]
and [Ni(bipy) ] [Ag(CN) ] Cl ϫ 9 H O.
The structure of
3
2
2 3
2
1
7 contains an analogous layer arrangement as seen before
in 16 (Figure 2b). Noteworthy in 18 is the hydrogen bond-
ing from the amino groups to both the sulfur and the nitro-
gen end of the SCN anions.
Figure 4. (a, top) Section of the one-dimensional coordination po-
Figure 3. Exemplified view of the molecular structure of the tris-
1
lymer
ϱ 4 2 2 2
[Cu(µ-SO )(5)(H O) ] ϫ 3 H O (19) indicating also part of
chelate)metal
cations
ϫ 2.5 H O (17), [Ni(5)
](NO (22); selected distances and angles are given in
in
[Fe(5)
3
]SO
4
ϫ 9
H
2
O
(16),
the hydrogen bonding network with two water molecules of crystal-
[
Ni(5)
3
]Cl
3
2
2
3
](SCN)
2
(18, shown here), and
˚
lization; selected distances [A] and angles [°]: CuϪN31 2.010(2),
in [Zn(5)
3 2
)
CuϪN32 1.992(2), CuϪO91 2.006(2), CuϪO93 1.993(2), CuϪO1
Table 3
2
.468(2), CuϪO2#1 2.311(2); N32ϪCuϪO93 175.08(6), O91Ϫ
CuϪN31 168.89(6), O1ϪCuϪO2#1 173.73(6), O93ϪCuϪO91
2.61(6), N32ϪCuϪN31 82.10(6), O1ϪCuϪN31 86.54(6),
9
1
ϱ[Cu(µ-SO )(5)(H O) ] ؋ 3 H O (19)
4
2
2
2
O1ϪCuϪO91 84.38(6), O91ϪCuϪO2#1 90.03(6), N31ϪCuϪO2
9
8
9.33(5), other angles between cis-positioned atoms range from
8.3 and 93.6° (symmetry equivalent position #1 ϭ x Ϫ 1, y, z;
Figure 4a shows a section of the 1-dimensional coordi-
nation polymer and Figure 4b displays the stabilizing πϪπ #4 ϭ x Ϫ 0.5, Ϫy ϩ 0.5, z Ϫ 0.5); (b, bottom) π-π stacking of
˚
[57]
neighboring strands, running along a
interaction (about 3.4 A)
of adjacent strands. The chains
Table 3. Selected bond lengths and angles in the tris(chelate)metal complexes [M(5)
3
]2
ϩ
ϩ
]2 (in 16)[a]
]2ϩ (in 17)[a]
]2ϩ (in 18)
[Zn(5)
3
]2ϩ (in 22)
[
Fe(5)
3
[Ni(5)
3
[Ni(5)
3
˚
MϪN range [A]
1.941(9)Ϫ1.995(9)
2.075(4)Ϫ2.095(3)
2.0742(15)Ϫ2.1152(16)
2.145(3)Ϫ2.212(3)
˚
MϪN average [A]
1.968
2.084
2.094
2.167
NϪMϪN chelate
bite angles [°]
81.9(4) (3 ϫ), 82.0(4),
82.2(3), 82.3(4)
78.9(2), 79.0(2), 79.1(2) (2 78.83(6), 79.04(6), 79.07(6) 76.4(1), 77.6(1), 77.9(1)
ϫ), 79.3(2), 79.4(2)
NϪMϪN cis, except
chelate, range [°]
88.7(4)Ϫ96.9(4)
90.4(1)Ϫ96.8(1)
91.32(6)Ϫ97.26(6)
92.6(1)Ϫ97.1(1)
average NϪMϪN cis,
except chelate [°]
92.7
93.8
93.89
94.6
NϪMϪN trans [°]
172.7(4), 173.2(4), 173.9(4), 168.1(2), 169.4(1), 170.1(1), 169.05(6), 170.36(5),
75.1(4), 175.2(4), 175.6(4) 170.5(2), 173.7 (2), 173.8(1) 173.13(6)
166.6(1), 167.3(1),
169.6(1)
1
[
a]
Two symmetically independent molecules in the unit cell.
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
1513

C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
62]
FULL PAPER
are formed through the bridging action of the sulfato li- H O[
and to the various structures of [Zn(bipy)3]-
2
gand, two of which are arranged trans around the copper ClO4)2[ as recent examples. Of more interest is an ex-
center with JahnϪTeller-elongated CuϪO contacts. The tended, two-dimensional hydrogen-bonded network formed
aqua and sulfato ligands on the metal center and the water by the nitrate anions, the water molecules of crystallization
molecules of crystallization form a three-dimensional hy- and the amino functions of the bipyridine ligands (Figure
drogen-bonding network surrounding the π-interacting 6). These hydrogen-bonded grids separate and sandwich the
63]
double strands from Figure 4.
layers build from the tris(chelate) complex molecules (and
vice versa). Within such a network the amino groups hydro-
gen-bond either to one (N56) or two nitrate ions (N53,
[
CuCl (5)] (20)
2
The structure of this molecular complex is displayed in N54, N55) or bridge with their hydrogen atoms between a
Figure 5. The copper atom is four-coordinate with a coordi- nitrate anion and a water molecule (N52) or between two
nation polyhedron between square-planar and tetrahedral. water molecules (N51). One of the hydrogen atoms from
The dihedral angle between the plane of the five-membered N54 thereby forms a 3-center or bifurcated bridge to two
chelate ring and the ClϪCuϪCl plane is 41.1°. In the com- oxygen atoms (O1 and O2) of a nitrate ion. One of the
plex (3-amino-6,6Ј-dimethyl-2,2Ј-bipyridine)dichlorocop- water molecules (O92) bridges between two nitrate anions
per(II) a (JahnϪTeller-)compressed tetrahedral structure is and accepts a hydrogen bond from the other solvent water
found since the methyl groups ortho to the coordinating ni- (O91). The latter forms hydrogen bonds between a nitrate
trogen atom apparently prevent a more planar ligand ar- ion and a water molecule and the oxygen atom accepts three
[
58]
rangement.
An approximately square-planar coordi- hydrogen bonds from amino groups to become five-coordi-
nation around Cu is observed in (2,2Ј-bipyridine-3,3Ј-dicar- nate. Each of the nitrate ions is anchored by five or six
boxylic acid)dichlorocopper(II) monohydrate.[ However, hydrogen bonds, four of which are derived from the amino
59]
˚
weak intermolecular interactions with a Cl atom (3.117 A) groups and the remaining one or two from water molecules.
˚
and an O atom (2.678 A away) on adjacent molecules com- Figure 6 illustrates the hydrogen-bonded network and Table
plete an octahedral donor arrangement around the metal 4 provides further details.
center. In 20 no such intermolecular interactions can be
found; the next chlorine contact to a neighboring molecule
˚
is 5.28 A. The absence of bridging chlorine atoms in 20 is
unusual as in the related compounds dichloro(4,4Ј-di-
[
60]
methyl-2,2Ј-bipyridine)copper(II) hemihydrate
and in di-
chloro(2,2Ј-bipyridine)copper(II)[ such intermolecular in-
teractions are present leading to five- and six-coordinate
copper centers in dimeric and polymeric structures, respec-
tively. The chlorine atoms in 20 are involved in hydrogen
61]
˚
bonding to the amino group (H···Cl 2.799 and 2.858 A, see
Figure 8a), yet, it is unclear if this is sufficient to prevent
coordination to the copper atom (see below). That such in-
termolecular interaction are feasable is demonstrated with
the structure of 1 [Cd(µ-Cl) (5)] ϫ 2 H O (25). The packing
ϱ
2
2
˚
of the molecules of 20 (πϪπ distances around 3.4 A) is dis-
cussed in combination with the related structure of 25 below.
Figure 6. Two-dimensional hydrogen bonding network in
3 2
](NO ) (22) in the ab plane; the nitrogen atoms of the
[
Zn(5)
3
amino groups are drawn as empty ellipsoids only; due to space
requirements only part of the atom positions are labelled and sym-
metry operations are not shown
1ϱ[Cd(µ-Cl) (5)] ؋ 2 H O (25)
2
2
The building block for this one-dimensional coordination
polymer is drawn in Figure 7a. At first sight, the structure
A] and angles [°]: CuϪN3 1.981(1), CuϪCl 2.2346(4); is similar to the copper complex 20. The dihedral angle be-
2
Figure 5. Molecular structure of [CuCl (5)] (20); selected distances
˚
[
N3ϪCuϪN3#2 82.28(8), N3ϪCuϪCl 97.41(4), N3ϪCuϪCl#2
50.80(4), ClϪCuϪCl#2 96.61(2) (symmetry equivalent position
2 ϭ Ϫx ϩ 1, y, Ϫz ϩ 0.5)
tween the plane of the five-membered chelate ring and the
ClϪCdϪCl plane is 17.8°. However, unlike 20 the cadmium
compound forms 1D strands (Figure 7b). Polymer forma-
tion is based on the bridging action of the chloro ligands
as is evident from Figure 7b. The distorted octahedral coor-
dination sphere of cadmium thus consists of the two bipyri-
1
#
[
Zn(5) ](NO ) ؋ 2 H O (22)
3 3 2 2
The unspectacular tris(chelate) structure is again found in dine nitrogen atoms and four bridging chlorine atoms. The
˚
2
2 (cf. Figure 3, Table 3). We refer to [Zn(bipy) ](SCN) ϫ 7 cadmiumϪchlorine (2.561, 2.781 A) and cadmiumϪcad-
3
2
1514
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
FULL PAPER
3 3 2 2
Table 4. Hydrogen bonding interactions in [Zn(5) ](NO ) ϫ 2 H O
(22); symmetry equivalent positions: #4 ϭ Ϫy Ϫ 0.25, Ϫx ϩ 0.75,
z Ϫ 0.25; #6 ϭ Ϫx ϩ 1, Ϫy ϩ 0.5, z; #7 ϭ x Ϫ 0.25, Ϫy ϩ 0.25,
z Ϫ 0.25; #9 ϭ Ϫx ϩ 1, Ϫy ϩ 1, Ϫz; #12 ϭ Ϫy ϩ 1.25, x ϩ 0.25,
Ϫz ϩ 0.25; #14 ϭ x, y ϩ 0.5, Ϫz; #15 ϭ y Ϫ 0.25, Ϫx ϩ 1.25,
Ϫz ϩ 0.25
˚
˚
˚
DϪH···A
DϪH [A] H···A [A] D···A [A] DϪH···A [°]
N51ϪH51B···O91
0.880(4) 2.258(4) 3.048(6) 149.3(3)
N51ϪH51A···O91#15 0.879(4) 2.326(4) 3.051(5) 139.8(3)
N52ϪH52A···O91#4 0.880(5) 2.445(4) 3.038(6) 125.1(3)
N52ϪH52B···O5#4
N53ϪH53A···O2#6
N53ϪH53B···O4
N54ϪH54A···O1#7
N54ϪH54A···O2#7
N54ϪH54B···O2#9
N55ϪH55A···O6#15 0.880(4) 2.457(6) 3.114(7) 131.9(3)
N55ϪH55B···O1#15 0.878(4) 2.146(4) 3.004(5) 165.5(3)
N56ϪH56A···O6#14 0.880(4) 2.137(6) 3.010(7) 171.5(4)
O91ϪH911···O92
O91ϪH912···O5
O92ϪH921···O3
O92ϪH922···O4#12
0.881(5) 2.302(5) 3.061(7) 144.4(4)
0.882(4) 2.128(4) 2.923(5) 149.7(3)
0.879(5) 2.069(5) 2.889(7) 154.9(3)
0.881(4) 2.326(4) 3.148(6) 155.3(4)
0.881(4) 2.456(5) 3.217(6) 144.9(3)
0.879(5) 2.177(4) 3.029(6) 163.2(3)
Figure 7. (a, top) Building block for the one-dimensional coordina-
1
0.908(19) 1.881(19) 2.657(7) 142.1(19)
tion polymer [Cd(µ-Cl) (5)] ϫ 2 H O (25) and (b, bottom) partial
ϱ
2
2
0.89(2)
0.83(4)
0.82(3)
2.34(2)
2.31(5)
2.36(4)
2.901(6) 120.9(19)
2.742(8) 113(3)
2.892(8) 123(4)
packing diagram which shows the formation of one-dimensional
strands; the water molecules of crystallization have been omitted
˚
for clarity; selected distances [A] and angles [°]: CdϪN1 2.332(8),
CdϪCl,Cl#3 2.561(8), CdϪCl#5,7 2.78(1); N1ϪCdϪN1#3
7
0.2(4),
N1ϪCdϪCl
159.6(11),
N1ϪCdϪCl#7
96.5(2),
ClϪCdϪCl#3 103.2(3), N1#3ϪCdϪCl 94.5(3), N1#3ϪCdϪCl#7
˚
mium (4.04 A) distances found here are typical for chloro- 85.8(2), ClϪCdϪCl#7 95.7(3), Cl#3ϪCdϪCl#7 82.5(3)
bridged cadmium compounds.[64] The amino groups are not
involved in metal coordination but take part in the hydro-
gen bonding network build up by the water of crystalliza-
tion.
Cl#7ϪCdϪCl#5 177.17(4) (symmetry transformations: #3 ϭ Ϫx,
y, Ϫz ϩ 0.5; #5 ϭ Ϫx, Ϫy, Ϫz; #7 ϭ x, Ϫy, z ϩ 0.5)
The packing and strand formation in 25 by chlorine the ring overlap is larger in the copper than in the cadmium
bridging can be compared to the packing of the molecular compound. On the basis of the molecular copper complex
complexes of 20. Figure 8 contrasts similar views of the unit in Figure 8a, the metalϪchlorine bridging in 25 (Figure 8b)
cells of both compounds. It can be seen that the bipyridine can be developed by stretching the a axis and shortening
˚
[57]
πϪπ stacking (both from 3.4 A on in 20 and in 25)
is an the b axis. CadmiumϪchlorine bridging can then occur
important motif to control the intermolecular arrangement, along b between the CdCl moieties which face each other.
2
as was also pointed out in Figure 4 for the copper complex Starting from the complete ring overlap in 20 the bridging
1
9; π strands are formed with the MCl moieties alternat- in 25 is enhanced at the cost of the bipyridine π overlap by
2
ingly facing to the left and right of these stacks. These π moving the (bipy)CdCl moieties to the left and right in the
2
interactions may be more important in 20 than in 25, since b direction, so that the ring overlap is greatly diminished.
1
Figure 8. (a, left) unit cell of [CuCl
2
(5)] (20) and (b, right) unit cell of
ϱ 2 2
[Cd(µ-Cl) (5)] ϫ 2 H O (25), both viewed approximately along
c, to compare the relationship between the unbridged and chlorine-bridged packing; hydrogenϪchlorine bonding is indicated in 20; the
water molecules of crystallization in 25 have been omitted for clarity
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
1515

C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
FULL PAPER
was dried at 0.05 mbar at 80°C for 3 h. Then, 30 mL (0.29 mol) of
Conclusions
3
-methylpyridine (8) was slowly added dropwise under ice-cooling
The expectation that the potentially ambidentate group and the reaction mixture was kept for 5 d at an oil-bath tempera-
ture of 180°C. The product was filtered hot through a D3 frit and
the Raney nickel residue washed twice with hot toluene. (The
5
,5Ј-diamino-2,2Ј-bipyridine (5) could function as a bridg-
ing and/or chelating bi- to tetradentate ligand in the coordi-
nation of transition metals has not been fulfilled. This may
be traced to the delocalization of the amine lone-pair into
the electron-deficient pyridine ring. The structural studies
showed a well-developed coplanarity of the amino group
with the aromatic ring. However, the amino function takes
Raney nickel was slowly dissolved with water, medium concen-
trated HCl and conc. HNO .) The filtrate was freed from the start-
3
ing compound and toluene by vacuum distillation. The product
was sublimed twice and obtained in colorless needle-shaped crys-
[13][14]
tals (yield 9.5 g, 36%; ref.
17%). Ϫ The procedure could easily
scaled up six-fold: From 125 g of nickel/aluminum alloy, 160 g of
part in hydrogen bonding to the anions and to incorporated NaOH, two times 600 mL of degassed water and 188 mL of 3-
water molecules of crystallization. From this a two- to methyl-pyridine was obtained 55 g of 9 (31%). A 2-l flask was used
three-dimensional hydrogen-bonding network was created as the reaction vessel and the reaction mixture was kept for 4 d at
1
80°C. The Raney nickel residue was washed three times with 80
which was one of the factors in the packing of the molecu-
lar or extended ligandϪmetal complexes. The other key fac-
tor responsible for the supramolecular arrangement of the
[13]
mL of hot toluene, each. Ϫ M.p. 114°C (ref.
114.5Ϫ115°C. Ϫ
1
H NMR (CDCl
3
): δ ϭ 8.41 (d, 2 H, J ϭ 1.5 H, H6, H6Ј), 8.17
ϭ 8.0 Hz, J
). Ϫ 13C NMR (CDCl
): δ ϭ
(
d, 2 H, J ϭ 9.0 Hz, H4, H4Ј), 7.52 (dd, 2 H, J
1
2
ϭ
5
,5Ј-diamino-2,2Ј-bipyridineϪmetal entities is a face-to-
2
1
1
.0 Hz, H3, H3Ј), 2.29 (s, 6 H, CH
3
3
face πϪπ stacking interaction between bipyridine ligands
of neighboring ligandϪmetal fragments. The importance of
such a πϪπ stabilization[ for the ligandϪmetal packing
has also been elucidated in the structures of the metal com-
53.7 (C2, C2Ј), 149.5 (C6, C6Ј), 137.3 (C4, CЈ), 132.9 (C5, C5Ј),
20.2 (C3, C3Ј), 18.2 (methyl-C). Ϫ The numbering for the NMR
57]
notation for 5, 9؊12 is as in Scheme 4.
[2]
plexes with 2,2Ј-dimethyl-4,4Ј-bipyrimidine (2), 5,5Ј-dicy-
[
3]
ano-2,2Ј-bipyridine (3),
(
and 2,2Ј-bi-1,6-naphthyridine
[
4]
4). These last three ligands also exhibit the sought for
bridging and/or chelating bi- to tetradentate metal coordi-
nation.
Scheme 4. Numbering scheme for bipyridines
Diethyl 2,2Ј-Bipyridine-5,5Ј-dicarboxylate (10): 9.45 g (51 mmol) of
Experimental Section
9
were added to a solution of 50.0 g (317 mmol) of KMnO
mL of water. The mixture was refluxed until decolorization had
occurred. The solution was filtered from precipitated MnO and
4
in 600
1
General: NMR: Bruker ARX 200 (200.1 MHz for H, 50.3 MHz
for 13C) or Varian O-300 (300.0 MHz for H, 75.4 MHz for C);
1
13
2
1
calibrated against the solvent signal ([D
6
]DMSO: H NMR: δ ϭ
: H NMR: δ ϭ 7.26; C NMR:
the filtrate acidified with half-concentrated HCl. A fine colorless
powder of 2,2Ј-bipyridine-5,5Ј-dicarboxylic acid precipitated. This
intermediate (M.p. > 280°C) was separated by filtration, dried in
vacuo and suspended in 200 mL of dried ethanol. After careful
.53; 13C NMR: δ ϭ 39.5; CDCl
1
13
2
3
1
13
δ ϭ 77.0; C
6
D
6
: H NMR: δ ϭ 7.19; C NMR: δ ϭ 128.0). Ϫ
Thermogravimetric analyses: simultaneous thermoanalysis appar-
atus STA 429 from Netsch. Ϫ IR spectra: PerkinϪElmer 783 infra-
red spectrophotometer as KBr disks or as Nujol mulls. Ϫ Mass
spectra: GC/MS Finnigan MAT in solid-probe EI mode at an ion-
ization energy of 70 eV. Ϫ Elemental analyses: PerkinϪElmer el-
emental analyzer E 240 C. Ϫ Commercial triphenylphosphane was
dried for 24 h in vacuo at 50°C. Distilled water was carefully de-
gassed prior to use. Dimethyl formamide (DMF) was of technical
grade and was fractionally distilled with 10 vol-% of toluene and 2
vol-% of water. This prepurified DMF was stirred for 2 h over
2 4
addition of 50 mL of conc. H SO , the reaction mixture was re-
fluxed for 16 h to give a clear solution. The warm solution was
poured onto ice. The hitherto obtained precipitate was filtered,
washed several times with water, dried and recrystallized from etha-
nol to give 10 as colorless needles (yield 9.8 g, 64%). Ϫ M.p. 145°C
[12]
1
(
2
ref. : 147°C) Ϫ H NMR ([D
.5 Hz, H6, H6Ј), 8.54 (dd, 2 H, J
H4Ј), 8.44 (d, 2 H, J ϭ 8.6 Hz, H3, H3Ј), 4.38 (q, 4 H, J ϭ 7.1 Hz,
6
]DMSO): δ ϭ 9.18 (d, 2 H, J ϭ
1
ϭ 8.6 Hz, J ϭ 2.5 Hz, H4,
2
13
OCH
2
), 1.36 (t, 6 H, J ϭ 7.1 Hz, CH
64.2 (COOEt), 157.3 (C2, C2Ј), 149.8 (C6, C6Ј), 137.9 (C4, C4Ј),
26.2 (C5, C5Ј), 121.0 (C3, C3Ј), 61.0 (OCH ), 13.8 (CH ).
3 3
). Ϫ C NMR (CDCl ): δ ϭ
2
CaH under argon and then distilled under vacuum. 5-Amino-2-
chloropyridine (13b) was prepared as described in ref.
chloro-5-nitropyridine (13a) in 92% yield.
1
1
[20]
from 2-
2
3
2
,2Ј-Bipyridine-5,5Ј-dicarboxylic Diazide (11): 50 mL of an 80% hy-
slurry of 8.20 g
(27.3 mmol) of 10 in 50 mL of ethanol. The mixture was heated
highly pyrophoric! In a 250-mL three-necked flask 20 g of nickel/ for 3 h at an oil-bath temperature of 120°C to give a viscous mass
Synthesis of 5 from 3-Methylpyridine (8) (Scheme 1)
drazine hydrate solution was added to
a
5,5Ј-Dimethyl-2,2Ј-bipyridine (9): CAUTION: Dry Raney nickel is
aluminum alloy were added under inert gas and ice-cooling in por-
tions within 30 min to a solution of 25.6 g (0.64 mol) of NaOH in
which was filtered, washed with hot ethanol and dried in vacuo.
The intermediate dihydrazide (6.5 g) thus obtained was suspended
1
00 mL of water. The temperature increased quickly to 80°C. After at 0°C in 150 mL of conc. HCl. A solution of 3.88 g (56 mmol) of
complete addition, stirring was continued at 80°C for 1 h. Then NaNO in 30 mL of water was added dropwise to this slurry with
00 mL of water was added and the solution was decanted from the temperature kept always below 10°C. After a few hours, a clear
2
1
the Raney nickel. The latter was washed 20 times with 100 mL of
H O each, which was decanted each time after 2 min of stirring.
2
Afterwards the three-necked flask was fitted with a reflux con-
denser and a dropping funnel. The remaining water was first re-
moved with a water aspirator at 60°C, eventually the Raney nickel
yellow solution was obtained. Upon dilution with 750 mL of water
a colorless precipitate was produced which was filtered, washed sev-
eral times with water, twice with 30 mL of hot ethanol and dried
in vacuo to yield 6.72 g (84%) of a white powder. Ϫ M.p. > 300°C.
Ϫ1
Ϫ IR (Nujol): ν˜ ϭ 3076 cm w, 2730 w, 2182 w, 2143 w, 1728 w,
1516
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
696 s, 1595 m, 1556 w, 1560 w, 1467 s, 1380 m, 1290 m, 1282, 1238
m, 1182 m, 1238 w, 1182 w, 1160 w, 1130 w, 1120 w, 1058 w, 1034
w, 1000 w, 895 w, 870 w, 860 w, 751 w, 722 w.
FULL PAPER
1
Syntheses of Transition Metal Complexes
Tris(5,5Ј-diamino-2,2Ј-bipyridine)manganese(II)] Chloride Hydrate
14): To a solution of 76.2 mg (0.38 mmol) of MnCl ϫ 4 H O in
0 mL of distilled water was given a solution of 192.5 mg
1.03 mmol) of 5 in 25 mL of ethanol. The pale red solution was
[
(
2
(
2
2
5,5Ј-Bis(ethoxycarbonylamino)-2,2Ј-bipyridine
(12):
6.00 g
(20.4 mmol) of the diazide 11 was suspended in a mixture of 150
allowed to stand several days at room temperature. The bright red
cubic crystals were separated by filtration. Upon standing in air
the crystals slowly lose water of crystallization and turn opaque
mL of p-xylene and 150 mL of dried ethanol and refluxed for 18 h
to give a clear yellow solution. Upon cooling yellowish crystals
were obtained which after filtration were recrystallized from etha-
(
yield 222 mg, 82%). Ϫ A thermogravimetric analysis shows the
nol. The yield of the now colorless product was 6.5 g (97%). Ϫ
1
complete loss of crystal water at 101Ϫ145°C. At 290°C the loss of
one diaminobipyridine ligand takes place with possible formation
M.p. > 300°C. Ϫ H NMR ([D
6
]DMSO): δ ϭ 9.92 (s, 2 H, NH),
8.67 (d, 2 H, J ϭ 2.2 Hz, H6, H6Ј), 8.20 (d, 2 H, J ϭ 8.8 Hz, H3,
of [MnCl
Nujol): ν˜ ϭ 3420 cm w (br.), 3305 m (br.), 3200 w (br.), 1632
m, 1598 s, 1585 m, 1487 m, 1430 m, 1325 w (br.), 1319 m, 1300 m,
272 w (br.), 1262 w (br.), 1162 w, 1055 w, 1030 m, 1019 w, 965 w
br.), 890 w, 862 w, 852 w, 827 m, 758 w, 740 w, 728 m, 656 w, 650
w. Ϫ Tetrahydrate C30 MnN12 (756.56): calcd. C 47.62, H
.06, N 22.21; found C 47.56, H 4.05, N 22.31.
2 2
(5) ]. Above 360°C decomposition is observed. Ϫ IR
H3Ј), 7.97 (dd, 2 H, J
1
ϭ 8.8 Hz, J
CH ), 1.24 (t, 6 H, J ϭ 7.1 Hz, CH
6
C NMR ([D ]DMSO): δ ϭ 159.3 (EtOCONH), 155.0 (C2,
2
ϭ 2.4 Hz, H4, H4Ј), 4.14 (q,
Ϫ1
(
4
H, J ϭ 7.1 Hz, OCH
2
3
2
CH ).
3
13
Ϫ
1
(
C2Ј), 144.9 (C6, C6Ј), 141.5 (C4, C4Ј), 131.5 (C3, C3Ј), 125.6 (C5,
C5Ј), 66.4 (OCH ), 20.2 (CH ).
2
3
H38Cl
2
O
4
5,5Ј-Diamino-2,2Ј-bipyridine (5): 5.00 g (15.2 mmol) of the diure-
5
thane 12 was refluxed for 24 h in a mixture of 200 mL of ethanol
and 200 mL of 2  NaOH. After cooling to room temperature, the
solution was carefully neutralized and the alcohol distilled of at
normal pressure. Upon cooling the hydrate of the diamine 5 crys-
tallized as long needles which may be weakly pink colored due to
traces of iron. Further purification was achieved by sublimation at
[
Diazidobis(5,5Ј-diamino-2,2Ј-bipyridine)manganese(II)] (15): 15 mL
of an ethanolic solution of 5 (100 mg, 0.54 mmol) was added to 15
mL of an aqueous solution of MnCl ϫ 4 (110 mg,
.54 mmol) and stirred for 15 min. To this solution was added 5 mL
2
2
H O
0
3
of an aqueous solution of NaN (88 mg, 1.35 mmol). The resulting
yellow solution was left standing for 36 h at room temperature.
Then some undissolved solid was filtered and the filtrate was then
placed at ambient temperature. One month later, a yellow precipate
had formed on the bottom of the flask. Two months later, the yel-
low precipate had transformed into well-formed red-orange crystals
which were collected by filtration and washed with water and etha-
nol to give 123 mg of product (69%, based on 5). Ϫ IR (KBr): ν˜ ϭ
0.2 mbar and an oil-bath temperature of 190°C. Yield 1.97 g (70%).
Analytical data are given after the following procedure.
Synthesis of 5 by Coupling of 5-Amino-2-chloropyridine (Scheme 2):
In a 250-mL three-necked flask was placed 2.37 g (10 mmol) of
nickel dichloride hexahydrate and 10.5 g (40 mmol) of tri-
phenylphosphane. The flask was evacuated and refilled with argon
for three times. 100 mL of dried dimethyl formamide was added
Ϫ1
3430 cm w, 3372 s, 3304 s, 3207 s, 2078 s ν(N ), 2020 s ν(N ),
3
3
under inert gas and the solution rapidly turned blue. After PPh
and NiCl ϫ 6 H O had completely dissolved in DMF, 0.7 g
11 mmol) of zinc powder was added to the solution under inert
gas at 50°C and the solution slowly turned brown-red. After stir-
3
1620 s, 1604 s, 1588 s, 1485 s, 1438 s, 1350 w, 1328 m, 1311 s, 1295
m, 1275 s, 1165 m, 1125 w, 1060 w, 1030 m, 1025 m, 960 w, 934 m,
892 m, 865 w, 849 m, 838 s, 728 m, 698 w, 653 m, 630 m, 620 w,
592 w, 545 s, 520 m. Ϫ C H N Mn (511.40): calcd. C 46.96, H
2
2
(
2
0
20 14
ring this mixture for 1 h, 10 mL of a DMF solution with 1.28 g 3.91, N 38.36; found C 46.76, H 3.92, N 38.33.
10 mmol) of 5-amino-2-chloropyridine was added dropwise to the
(
[
Tris(5,5Ј-diamino-2,2Ј-bipyridine)iron(II)] Sulfate Hydrate (16): To
a hot solution (90°C) of 532 mg (2.86 mmol) of 5 in 30 mL of
distilled water was added dropwise solution of 280 mg
1.01 mmol) of FeSO ϫ 7 H O in 10 mL of distilled water. A red
mixture. Stirring was continued for 4 h at 50°C at which time the
starting material could not be detected anymore by thin-layer chro-
matography (eluent ethyl acetate). The reaction mixture was then
concentrated in vacuo to half of its volume. After adding 250 mL
of water, the mixture was carefully poured into 150 mL of conc.
ammonia and stirred for 18 h. The solution turned blue because of
a
(
4
2
color immediately developed. After complete addition, the solution
was allowed to cool and the precipitated crystals were washed with
a few mL of ice-cooled water, then with dried ethanol and finally
with diethyl ether. The crystals were briefly dried in air. Single crys-
tals could best be obtained by cooling a saturated solution from
room temperature to 0°C (yield 720 mg, 92%). Ϫ A thermogravi-
metric analysis shows the complete loss of water of crystallization
at 166°C and decomposition above 350°C. Ϫ H NMR (D
7
3
the formation of hexaamminenickel(II) complexes. The PPh pre-
cipate was removed by filtration and the filtrate was extracted three
times with 50 mL of dichloromethane each. The combined organic
phases were treated with 50 mL of half-concentrated HCl for three
times each to separate the diaminobipyridine from PPh . During
3
this procedure strongly colored aminohydrochlorides of 5 were
formed. The combined acidic aqueous phases were carefully neu-
tralized with a 10% Na
a yellowish solid and was sublimed as described above to give a
colorless powder (yield 1.11 g, 60%). Ϫ M.p. 205°C (ref.
1
2
O): δ ϭ
ϭ 2.4 Hz, H4,
O): δ ϭ 149.6
C2, C2Ј), 144.7 (C5, C5Ј), 139.3 (C6, C6Ј), 123.1 (C4, C4Ј), 121.4
1 2
.99 (d, J ϭ 8.8, H3, H3Ј), 7.29 (dd, J ϭ 8.8 Hz, J
1
3
H4Ј), 6.85 (d, J ϭ 2.4 Hz, H6, H6Ј). Ϫ C NMR (D
(
(
2
2 3
CO solution. The product 5 separated as
Ϫ1
C3, C3Ј). Ϫ IR (Nujol): ν˜ ϭ 3420 cm w, 3340 w, 3205 w, 1632
[12]
s, 1602 s, 1580 m, 1575 w, 1488 s, 1429 m, 1368 s, 1352 m, 1328 m,
2
2
05Ϫ206°C). Ϫ 1H NMR ([D
.8 Hz, H6, H6Ј), 7.84 (d, 2 H, J ϭ 8.6 Hz, H3, H3Ј), 6.95 (dd, 2
ϭ 8.6 Hz, J ϭ 2.5 Hz, H4, H4Ј), 5.30 [s (br.), 4 H, NH ]. Ϫ
C NMR (CDCl ): δ ϭ 144.7 (C2, C2Ј),143.6 (C5, C5Ј), 134.9
C6, C6Ј), 120.5 (C3, C3Ј), 119.0 (C4, C4Ј); ([D ]DMSO): δ ϭ
6
]DMSO): δ ϭ 7.92 (d, 2 H, J ϭ
1
8
310 s, 1292 m, 1268 m, 1206 m, 1165 m, 1028 w, 1019 w, 904 w,
60 w, 838 w, 832 w, 728 w, 655 w. Hexahydrate
10S (818.65): calcd. C 44.01, H 5.17, N 20.53; found
C 44.16, H 4.20, N 20.50.
Ϫ
H, J
1
2
2
30
C H42FeN12O
1
3
3
(
6
Ϫ1
1
3
1
1
5
47.1, 145.5, 136.6, 123.5, 122.2. Ϫ IR (KBr): ν˜ ϭ 3424 cm w, [Tris(5,5Ј-diamino-2,2Ј-bipyridine)nickel(II)] Chloride Hydrate (17):
A solution of 158 mg (0.66 mmol) NiCl
568 m, 1478 s, 1412 m, 1289 m, 1248 w, 1137 w, 1108 w, 1088 w, distilled water was combined with
338 m, 3310 m, 3207 m, 3062 w, 3057 w, 3005 w, 1632 w, 1600 m,
2
2
ϫ 6 H O in 30 mL of
a
solution of 383 mg
060 w, 1024 w, 920 w, 897 w, 846 m, 832 m, 737 w, 656 m, 552 m,
17 m, 509 w, 418 w.
(2.05 mmol) of 5 in 25 mL of ethanol. The mixture was heated
to reflux and a pale red solution formed. After cooling to room
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
1517

C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
FULL PAPER
temperature, the precipitate was filtered, washed with little cold
water, ethanol, and diethyl ether and air-dried (yield 150 mg, 85%).
Single crystals could be obtained by slow cooling of a saturated
solution from room temperature to 0°C. The product crystallizes
in bright red cubes, which slowly loose water of crystallization in
air. Ϫ A thermogravimetric analysis shows the complete loss of
[(5,5Ј-Diamino-2,2Ј-bipyridine)dinitratozinc(II)] (21): A solution of
64 mg (0.22 mmol) of Zn(NO ϫ H O in 5 mL of distilled water
was overlayered in a test tube first with 2 mL of ethyl acetate and
then with a solution of 35 mg (0.19 mmol) of 5 in 4 mL of ethanol.
After standing for several days, colorless rhombohedra had formed
at the boundary layer, which were carefully separated, washed with
)
3 2
2
water of crystallization at 168°C and decomposition above 280°C. little THF and air-dried (yield 55 mg, 77%). Ϫ When 21 was heated
Ϫ1
Ϫ IR (Nujol): ν˜ ϭ 3420 cm w (br.), 3320 w (br.), 3200 m (br.), with two equivalents of 5 in water crystals formed upon cooling
1
1
630 m, 1602 s, 1579 m, 1486 s, 1432 m, 1321 m, 1300 m, 1272 m,
260 w, 1161 w, 1060 w, 1054 w, 1031 w, 1019 w, 960 w (br.), 888
which were shown by analysis to have a 3:1 ligand/metal ratio as
in 22.
w, 868 w, 852 w, 828 m, 722 w, 654 m, 596 w, 532 w, 428 w. Ϫ
Hexahydrate C30 12NiO (796.34): calcd. C 45.25, H 5.31,
N 21.11; tetrahydrate C30 38Cl
H 4.99, N 22.10; 2.5-hydrate C30
[
Tris(5,5Ј-diamino-2,2Ј-bipyridine)zinc(II)] Nitrate Hydrate (22): To
2
H42Cl N
6
a solution of 167.5 mg (0.56 mmol) Zn(NO ϫ 6 H O in 20 mL
)
3 2
2
H
2
N
12NiO (760.31): calcd. C 47.39,
4
of distilled water was added 332.8 mg (1.79 mmol) of 5 and the
mixture heated to reflux for 30 min which led to a clear solution.
After cooling to room temperature, the crystals formed were sepa-
rated by filtration, washed with little ice-cooled water, ethanol and
H
35Cl N12NiO2.5 (733.28): calcd.
2
C 49.13, H 4.81, N 22.92; found C 47.64, H 4.08, N 22.39.
[Tris(5,5Ј-diamino-2,2Ј-bipyridine)nickel(II)] Thiocyanate (18): To
an aqueous solution (100 mL) of NiCl ϫ 6
.69 mmol or 0.32 g, 1.35 mmol) was added a DMF solution (10
mL) of 5 (0.50 g, 2.69 mmol). After stirring for 2 h, 50 mL of conc. by slow cooling of a saturated solution from room temperature to
2
H
2
O
(0.64 g, diethyl ether. After drying in air, the complex was obtained as a
2
light yellow fine crystalline powder. Single crystals were obtained
ammonia was added and stirring was continued for 20 h. During
this time the solution changed color from yellow to brown. 20 mL
of the aforementioned solution (containing 80 mg/0.34 mmol or composition above 335°C. Ϫ H NMR (D
0°C (yield 320 mg, 69%). Ϫ A thermogravimetric analysis shows
complete loss of the water of crystallization at 179°C and de-
1
2
O):δ ϭ 8.43 (d, J ϭ
ϭ 2.6 Hz, H4, H4Ј), 7.79
]DMSO): δ ϭ 8.08 (d, J ϭ 8.7, H3,
ϭ 8.7 Hz, J ϭ 2.5 Hz, H4, H4Ј), 7.08 (d, J ϭ
O):δ ϭ 145.5 (C2, C2Ј), 140.8
40 mg/0.17 mmol of nickel and 62 mg/0.34 mmol of 5) was used to
8.6, H3, H3Ј), 7.84 (dd, J
(d, J ϭ 2.6 Hz, H6, H6Ј); ([D
H3Ј), 7.19 (dd, J
1 2
ϭ 8.6 Hz, J
overlayer 5 mL of an aqueous solution of 33 mg (0.34 mmol) of
KSCN in a test tube. The solution was allowed to stand for 15 d
at ambient temperature. The resulting orange-brown crystals were 2.5 Hz, H6, H6Ј). Ϫ C NMR (D
6
1
2
1
3
2
collected by filtration, washed with water and ethanol and dried
under vacuum (yield 66Ϫ76 mg, 54Ϫ66% based on 5).
14NiS
1.45, H 4.11, N 26.41. Ϫ IR (KBr): ν˜ ϭ 3438 cm m, 3300 m,
190 m, 2076 s ν(SCN), 2048 s ν(SCN), 1630 s, 1602 s, 1580 s, 1460 w, 892 w, 867 w, 850 w, 838 w, 828 m, 722 m, 658 w. Ϫ Dihydrate
(C5, C5Ј), 134.4 (C6, C6Ј), 126.1 (C4, C4Ј), 122.2 (C3, C3Ј). Ϫ IR
Ϫ1
Ϫ
(Nujol): ν˜ ϭ 3430 cm w (br.), 3325 w (br.), 3210 w (br.), 1630 m,
C
5
3
32
H
30
N
2
(733.50): calcd. C 52.41, H 4.09, N 26.75; found C 1602 s, 1582 m, 1488 m, 1378 m, 1342 m, 1320 m, 1316 m, 1272
Ϫ1
m, 1160 w, 1152 w, 1142 w, 1080 w, 1060 w, 1031 w, 1019 w, 898
s, 1443 s, 1318 m, 1310 m, 1300 m, 1275 m, 1170 m, 1163 m, 1148
w, 1060 w, 1035 m, 1021 w, 858 w, 840 m, 825 m, 744 w, 725 m,
C
30
H
34
N
14
O
8
Zn (784.07): calcd. C 45.94, H 4.37, N 25.00; found
C 45.61, H 3.32, N 25.05.
7
00 w, 660 s, 550 m. Ϫ C32
30 2
H N14NiS (733.50): calcd. C 52.41, H
[
(5,5Ј-Diamino-2,2Ј-bipyridine)nitratosilver(I)] Hydrate (23): A solu-
4.09, N 26.75; found C 51.56, H 4.19, N 26.57.
tion of 122 mg (0.72 mmol) of AgNO in 10 mL of distilled water
was overlayered in a test tube first with 3 mL of dried ethyl acetate
and then with a solution of 104 mg (0.56 mmol) of 5 in 15 mL of
3
1ϱ
[Diaqua(5,5Ј-diamino-2,2Ј-bipyridine)(µ-sulfato)copper(II)]
drate (19): A 25-ml flask was charged with mixture of CuSO
Hy-
4
ϫ 5
2
H O (135 mg, 0.54 mmol), 5 (100 mg, 0.54 mmol) and 10 mL of dried ethanol. After standing for several weeks at room tempera-
water, sealed and heated in an oil bath to 120°C for 48 h. After
cooling, the dark-green crystals formed were collected by filtration
and washed with water and ethanol. Concentration of the filtrate
by slow evaporation of the solvent at room temperature for 8 d
gave another crop of well-formed dark-green crystals. A total yield
ture in the dark, yellowish fiber clusters had formed at the layer
boundary. They were separated by filtration, washed with some
cold water, ethanol and finally diethyl ether. Drying in air gave light
1
yellow fibers (yield 1.66 mg, 76%). Ϫ M.p. > 195°C (dec.). Ϫ H
NMR ([D
6
]DMSO): δ ϭ 7.92 (d, J ϭ 2.6 Hz, H6, H6Ј), 7.91 (d,
ϭ 8.6 Hz, J ϭ 2.6 Hz, H4,
]DMSO): δ ϭ 145.2 (C2, C2Ј), 140.4 (C5,
to m, 1324 w, 1280 w, 1210 w, 1140 m, 1115 m, 1040 w, 955 w, 925 C5Ј), 136.2 (C6, C6Ј), 121.9 (C4, C4Ј), 121.2 (C3, C3Ј). Ϫ IR (Nu-
Ϫ1
of 183 mg (89%) was obtained. Ϫ IR (KBr): ν˜ ϭ 3420 cm m,
J ϭ 8.8 Hz, H3, H3Ј), 7.15 (dd, J
1
2
1
3
3340 m, 3220 m, 1650 m, 1606 m, 1590 m, 1495 s, 1446 w, 1332 w H4Ј). Ϫ C NMR ([D
6
Ϫ1
w, 850 w, 839 w, 718 w, 660 w, 550 w. Ϫ C10
calcd. C 31.45, H 3.67, N 14.68; found C 31.32, H 3.84, N 14.70.
H
14CuN
4
O
6
S (381.86): jol): ν˜ ϭ 3450 cm w (br.), 3325 m (br.), 3210 w (br.), 1628 s, 1604
s, 1574 m, 1488 s, 1422 m, 1350 s, 1326 s, 1296 m, 1271 m, 1252 w,
153 w, 1062 w, 1043 w, 1022 w, 1018 w, 879 w, 862 w, 843 w, 819
w, 722 m, 652 m, 646 m. Ϫ C10 14AgN (392.12): calcd. C 30.63,
1
[Dichloro(5,5Ј-diamino-2,2Ј-bipyridine)copper(II)] (20): 10 mL of an
H
5 5
O
aqueous solution of CuCl ϫ 2 H O (92 mg, 0.54 mmol) was care-
2
2
H 3.60, N 17.86; found C 30.22, H 3.18, N 17.63.
fully overlayered in a test tube with 10 mL of an ethanolic solution
of 5 (100 mg, 0.54 mmol). The solution was allowed to stand for 7
[Bis(5,5Ј-diamino-2,2Ј-bipyridine)silver(I)] Nitrate (24): A slurry of
d at room temperature. After this time, the well-formed rod-shaped 225 mg (1.21 mmol) of 5 in 20 mL of distilled water was heated
dark-green crystals were collected by filtration and washed with
until complete dissolution. Then a hot solution of 110 mg
(0.65 mmol) of AgNO in 10 mL of water was added which im-
cold water and ethanol to give 14 mg of product (82%). Ϫ IR
3
Ϫ1
(
KBr): ν˜ ϭ 3448 cm s, 3346 s, 3210 w, 1615 s, 1603 s, 1580 m, mediately gave a colorless precipitate. This was shown by elemental
1
1
8
510 w, 1492 s, 1435 m, 1350 w to m, 1332 m, 1310 w, 1278 m,
220 m, 1161 w, 1156 w, 1064 w, 1038 m, 1022 w, 968 w, 885 w, ammonia was added dropwise until the precipitate had completely
36 s, 715 m, 665 w, 660 w, 550 m, 530 w. Ϫ C10 CuN dissolved. The solution was kept at room temperature open to the
analysis to have a 1:1 ligand/metal composition. Conc. aqueous
H10Cl
2
4
(322.66): calcd. C 37.44, H 3.12, N 17.47; found C 36.45, H 3.12, air and after a few days thin platelets with a mother-of-pearl shine
N 17.15. Ϫ The reaction of 5 in ethanol (or THF) with CuCl
O in water in the molar ratio of 1:2 also gave 20.
2
ϫ 2
had formed. The crystals were collected by filtration, washed with
diethyl ether and dried in vacuo (yield 171 mg, 52%). Ϫ M.p. >
H
2
1518
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521

Modified Bipyridines
FULL PAPER
1
2
30°C. Ϫ H NMR ([D
6
]DMSO): δ ϭ 7.91 (d, J ϭ 8.6 Hz, H3, cooling which were shown by analysis to have a 3:1 ligand/metal
H3Ј), 7.90 (d, J ϭ 2.3 Hz, H6, H6Ј), 7.12 (dd, J
1
ϭ 8.6 Hz, J
2
ϭ
ratio as in 26.
2.6 Hz, H4, H4Ј), 5.68 [s (br.), NH
2
]. Ϫ 13C NMR ([D
6
]DMSO):
[Tris(5,5Ј-diamino-2,2Ј-bipyridine)cadmium(II)] Chloride Hydrate
δ ϭ 145.1 (C2, C2Ј), 140.7 (C5, C5Ј), 136.0 (C6, C6Ј), 121.8 (C4,
C4Ј), 121.0 (C3, C3Ј). Ϫ IR (Nujol): ν˜ ϭ 3420 cm w, 3340 w,
Ϫ1
(26): In 20 mL of an aqueous solution of 117.5 mg (0.58 mmol) of
CdCl ϫ H O was suspended 336.0 mg (1.80 mmol) of 5 and
2
2
3
1
1
205 w, 1632 s, 1602 s, 1582 m, 1575 w, 1488 s, 1429 m, 1368 s,
352 m, 1328 m, 1310 s, 1292 m, 1268 m, 1206 m, 1165 m, 1028 w,
019 w, 904 w, 860 w, 838 w, 832 w, 728 w, 655 w. Ϫ C20H20AgN O
9 3
heated under reflux for 30 min. From the bright yellow solution
fine crystals formed upon cooling, which were filtered, washed with
little ethanol and diethyl ether and air-dried. Upon storage in air
(542.31): calcd. C 44.30, H 3.70, N 23.25; found C 44.73, H 3.95,
the crystals slowly lost incorporated solvent water (yield 350 mg,
N 23.46.
1
7
6%). Ϫ M.p. > 225°C. Ϫ H NMR ([D
6
]DMSO): δ ϭ 7.90 (d,
1ϱ
[Di(µ-chloro)(5,5Ј-diamino-2,2Ј-bipyridine)cadmium(II)] Hydrate
1
J ϭ 8.6, H3, H3Ј), 7.88 (d, J ϭ 2.6 Hz, H6, H6Ј), 7.09 (dd, J ϭ
(
25): A solution of 175 mg (0.87 mmol) CdCl
2
ϫ H
2
O in 10 mL of
13
8
1
1
.6 Hz, J
2 6
ϭ 2.6 Hz, H4, H4Ј). Ϫ C NMR ([D ]DMSO): δ ϭ
distilled water was overlayered in a test tube first with 3 mL of
ethyl acetate and then with a solution of 130 mg (0.70 mmol) of
44.9 (C2, C2Ј), 139.4 (C5, C5Ј), 134.6 (C6, C6Ј), 122.2 (C4, C4Ј),
20.4 (C3, C3Ј). Ϫ Cd NMR (66.0 MHz, ([D
113
6
]DMSO), standard
5
in 15 mL of ethanol. After standing for several days, colorless
is a 2.0  cadmium perchlorate solution in D
width 30 ppm. Ϫ IR (Nujol): ν˜ ϭ 3425 cm w, 3310 w, 3205 w,
2
Ϫ1
O): δ ϭ 254 (s), half
rhombohedra had formed at the boundary layer, which were care-
fully separated, washed with little THF and air-dried (yield 160 mg,
1
1
628 s, 1604 m, 1586 w, 1495 s, 1440 s, 1330 m, 1322 w, 1280 w,
269 w, 1172 w, 1168 w, 1130 w (br.), 1036 w, 1028 w, 970 w, 905
1
5
6%). Ϫ M.p. > 225°C. Ϫ H NMR ([D
6
]DMSO): δ ϭ 7.98 [s (br.),
ϭ 8.7 Hz, J
]. Ϫ 13C NMR ([D
]DMSO):
H6, H6Ј], 7.92 (d, J ϭ 8.7, H3, H3Ј), 7.14 (dd, J
.7 Hz, H4, H4Ј), 5.85 [s (br.), NH
1
2
ϭ
w, 888 w, 870 w, 833 m, 728 w, 668 w, 660 w. Ϫ Dihydrate
34CdCl (778.00): calcd. C 46.29, H 4.40, N 21.59;
2
2
6
30
C H
2 12 2
N O
δ ϭ 145.5 (C2, C2Ј), 138.0 (C5, C5Ј), 134.7 (C6, C6Ј), 122.8 (C4,
C4Ј), 120.8 (C3, C3Ј). Ϫ IR (Nujol): ν˜ ϭ 3510 cm w, 3338 m
found: C 45.59, H 3.85, N 21.48.
Ϫ1
(
br.), 3204 m (br.), 1638 m (br.), 1602 s, 1590 s, 1487 s, 1435 m,
326 w, 1315 w, 1300 m, 1272 m, 1266 m, 1160 m, 1130 w (br.),
X-ray Structure Determinations: Data were collected with Mo-K
radiation (λ ϭ 0.71073 A) and the use of a graphite monochroma-
α
˚
1
1
7
3
064 w (br.), 1030 m, 918 m, 862 msh, 845 s, 827 m (br.), 727 m, tor. Structure solution was performed by direct methods using
(405.56): calcd. C 29.59, H SHELXS-97.[
65]
Refinement: Full-matrix least-squares on F
2
00 w, 655 w. Ϫ C10
H
2
14CdCl N
O
4 2
[65]
.48, N 13.80; found C 30.55, H 3.22, N 13.23. Ϫ When 25 was
[SHELXL-97 (version 97Ϫ2)]; all non-hydrogen positions found
heated with two equivalents of 5 in water crystals formed upon and refined with anisotropic temperature factors. Crystal data are
Table 5. Crystal data for compounds 15Ϫ20, 22 and 25
Compound
15
16
17
18
19
20
22
25
[f]
[f]
Empirical formula
C
20
H
20
N
14Mn
C
60
H
96Fe
2
N
24
O
26
S
2
C
60
H
70Cl
4
N
2
24Ni O
5
C
32
H
30
N
14NiS
2
C
10
H
20CuN
435.899
0.25ϫ0.15ϫ0.09 1.08ϫ0.15ϫ0.09 0.46ϫ0.08ϫ0.08 0.76ϫ0.39ϫ0.25 0.30ϫ0.20ϫ0.20
4
O
9
S
C
10
H
10Cl
2
CuN
4
C
784.07
30
H
34
N
14
O
8
Zn
C
405.56
10
H
14CdCl
2 4 2
N O
Ϫ1
[f]
[f]
M [g mol
]
511.405
2x872.68
2x733.28
733.500
322.665
Crystal size [mm]
Crystal description
Crystal color
0.45ϫ0.35ϫ0.25 0.50ϫ0.30ϫ0.05
0.80ϫ0.50ϫ0.40
prismatic
red
prismatic
red-brown
200(3)
platelet
red
200(3)
prismatic
red
200(3)
needle
green
200(3)
needle
irregular
prismatic
colorless
293(2)
blue
200(3)
yellow-brown
200(3)
T [K]
200(3)
Diffractometer
Scan type, 2 Θ range [°]
h; k; l range
STOE-IPDS
ω, 4.6Ϫ55.8
Ϫ17, 17; Ϫ13, 14; Ϫ18, 18; Ϫ18, 18
Ϫ21, 20
monoclinic
I2/a
13.6751(13)
10.8010(6)
16.0833(14)
90
114.136(10)
90
2165.7(14)
4
1.568(1)
1052
6.53
STOE-IPDS
ω, 2.8Ϫ44.2
STOE-IPDS
ω, 3.7Ϫ51.6
Ϫ29, 29; Ϫ30, 24
Ϫ29, 27
monoclinic
C2/c
24.5144(18)
24.8858(15)
24.3872(19)
90
109.325(9)
90
STOE-IPDS
ω, 4.2Ϫ56.1
Ϫ13, 13; Ϫ14, 14; Ϫ8, 9; Ϫ25, 25
Ϫ18, 18
triclinic
P1¯
10.4923(11)
11.2927(12)
14.3883(14)
79.264(12)
74.867(12)
89.259(12)
1615.7(12)
2
STOE-IPDS
ω, 6.1Ϫ55.8
STOE-IPDS
ω, 6.2Ϫ55.5
STOE-IPDS
ω, 3.5Ϫ47.7°
Syntex P21
ω, 8Ϫ40°
Ϫ16, 16; Ϫ17, 17; Ϫ19, 12; Ϫ19, 19; 0, 20; 0, 9; 0, 7
Ϫ9, 9
Ϫ27, 27
orthorhombic
Ϫ16, 16
monoclinic
Ϫ51, 48
tetragonal
I4 /a
1
17.5457(12)
17.5457(12)
46.380(4)
90
90
90
14278.2(19)
16
1.4590(2)
6496
Crystal system
Space group
monoclinic
C2/c
12.9032(11)
13.5149(10)
7.3981(6)
90
112.987(9)
90
1187.74(15)
4
orthorhombic
Pbcn
21.02(12)
9.40(4)
7.32(4)
90
90
90
1446(13)
8
1.862
Pna2
1
1
P2 /n
˚
a [A]
17.4099(11)
17.2792(16)
26.3756(18)
90
90
90
7934(1)
4
1.4681(2)
3664
6.8693(6)
19.4875(13)
12.7217(10)
90
105.212(9)
90
1643.3(14)
4
1.7619(15)
900
˚
b [A]
˚
c [A]
α [°]
β [°]
γ [°]
˚
3
V [A ]
14039(2)
8
1.3877(2)
6096
Z
D
calcd. [g cmϪ3
]
1.508(1)
760
7.79
1.7933(2)
644
22.7
F(000) [electrons]
800
18.82
Ϫ1
µ [
]
5.09
7.53
15.1
7.58
Absorption correction
Max/min transmission
Measured reflections
Unique reflect. for
numerical
numerical
0.830/0.980
39521
numerical
0.687/0.786
26958
numerical
0.874/0.935
15188
numerical
0.390/0.861
15509
numerical
0.739/0.863
3746
numerical
0.619/0.753
20364
empirical
0.759/0.643
666
9648
2511 (0.0254)
9855(0.12)
12059(0.0485)
7146 (0.0258)
3890 (0.0831)
1045 (0.0275)
5421 (0.0568)
666 (0.0830)
refinemt. (Rint
Observed reflection
I > 2 σ(I)]
)
2234
7381
7354
5406
3431
939
4364
545
[
Parameters refined
199
0.386/Ϫ0.212
0.0271/0.0701
482
0.780/Ϫ0.489
0.087/0.226
0.108/0.235
1.090
897
562
306
98
492
88
Max/min ∆ρ [e AϪ3]
[
a]
˚
1.225/Ϫ0.580
0.061/0.169
0.098/0.188
0.931
0.345/Ϫ0.316
0.0304/0.0688
0.0467/0.0731
0.918
1.037/Ϫ0.732
0.0311/0.0829
0.0355/0.0846
1.006
0.304/Ϫ0.219
0.0205/0.0520
0.0235/0.0528
1.058
0.496/Ϫ0.302
0.0386/0.0855
0.0516/0.0889
0.945
0.742/Ϫ0.576
0.0489/0.1233
0.0528/0.1330
0.972
R1/wR2[ [I > 2 σ(I)]
b]
[g]
R1/wR2[ (all reflections) 0.0313/0.0718
b]
2
[c]
GOF on F
1.046
0.0481/0.4789
Weighting scheme w: a/b[
d]
0.109/26.376
0.1262/0.0000
0.0436/0.0000
0.0555/0.0000
0.0381/0.0000
0.0547/0.0000
0.1098/0.0000
[
a]
[b]
[c]
2
2 2
2 2 1/2
Largest difference peak and hole. Ϫ Largest difference peak and hole. Ϫ R1 ϭ (Σ F
o
Ϫ F
c
)/Σ F
o
; wR2 ϭ {Σ[w(F
o
Ϫ F
o
c
) ] / Σ[w(F ) ]}
2
o
.
[
d]
2
2 2
1/2
[e]
2
2
2
2
Ϫ
Goodness-of-fit, Gof ϭ {Σ [w(F
o
Ϫ F
c
) ]/(n Ϫ p)} . Ϫ w ϭ 1/[σ (F
o
) ϩ (a·P) ϩ b·P] where P ϭ [max(F
or 0) ϩ 2·F
c
]/3. Ϫ
[
f]
[g]
Two independent molecules in the unit cell. Ϫ Structure refinement was hampered by the disorder in the anion-water layer.
Eur. J. Inorg. Chem. 1999, 1507Ϫ1521
1519

C. Janiak, S. Deblon, H.-P. Wu, M. J. Kolm, P. Klüfers, H. Piotrowski, P. Mayer
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