Synthesis of polydendate acyclic and macrocyclic polyamine ligands bearing 2,2'-bipyridine or 2,2'-bipyridine N,N'-dioxide moieties

Article abstract of DOI:10.1055/s-1998-6107

The synthesis of various acyclic and macrocyclic complexing agents bearing bypyridine or bipyridine N,N'-dioxide substituents is reported. These ligands, which possess three, four, or six pendant units, have been prepared by a general synthetic protocol starling from the mono(bromomethyl)-2,2'-bipyridine or mono(bromomethyl)-2,2'-bipyridine N,N'-dioxide derivatives and the corresponding amine in the presence of a mineral base. NMR and FAB-MS spectral data indicate that tripode 5 and hexapode 9, respectively form stable, highly colored and redox-active mono-and diiron(II) complexes.

Full text of DOI:10.1055/s-1998-6107

September 1998
SYNTHESIS
1339
Synthesis of Polydendate Acyclic and Macrocyclic Polyamine Ligands Bearing 2,2'-
Bipyridine or 2,2'-Bipyridine N,N'-Dioxide Moieties
Raymond Ziessel,* Muriel Hissler, Gilles Ulrich
Laboratoire de Chimie, d’Électronique et de Photonique Moléculaires, UPRES-A 7008 au CNRS, École Chimie, Polymères, Matériaux
(ECPM), Université Louis Pasteur (ULP), 1, rue Blaise Pascal, F-67008 Strasbourg Cedex, France
Fax +33(3)88416825; E-mail: ziessel@chimie.u-strasbg.fr
Received 22 December 1997; revised 9 January 1998
Abstract: The synthesis of various acyclic and macrocyclic com-
plexing agents bearing bipyridine or bipyridine N,N'-dioxide sub-
stituents is reported. These ligands, which possess three, four, or
six pendant units, have been prepared by a general synthetic
protocol starting from the mono(bromomethyl)-2,2'-bipyridine or
mono(bromomethyl)-2,2'-bipyridine N,N'-dioxide derivatives and
the corresponding amine in the presence of a mineral base. NMR
and FAB-MS spectral data indicate that tripode 5 and hexapode 9,
respectively, form stable, highly colored and redox-active mono-
and diiron(II) complexes.
We report here the synthesis and complete characteriza-
tion of polypodate ligands bearing three, four, or six bpy
or bpy-N,N'-oxide fragments functionalized at the 5,5' po-
sition. While our work was in progress, the synthesis of a
triazacyclononane ligand functionalized with bpy subunit
was briefly described.13
The key starting material for these syntheses was 5-(bromo-
14
methyl)-5'-methyl-2,2'-bipyridine (1), obtained by radi-
15
Key words: podands, oligopyridines, multitopic ligands, iron
complexes
caloid bromination of 5,5'-dimethyl-2,2'-bipyridine with
N-bromosuccinimide (1 equiv) in the presence of 2,2'-
azobisisobutyronitrile as radical initiator. This synthesis
appears to be the most convenient, with the use of one
equivalent of NBS. Most of the dibromo derivative 2 can
The design of ligands bearing 2,2'-bipyridine (bpy) or
analogous subunits has received considerable interest in
be removed by crystallization in CCl while chromatogra-
1
4
the past twenty years or so. The remarkable intrinsic
phy of the residue gives the monobromomethyl 1 and di-
bromomethyl 2 derivatives in, respectively, 34 and 25%
isolated yield. Subsequent oxidation with 3-chloroperoxy-
benzoic acid afforded the corresponding N,N'-dioxide de-
rivatives 3 and 4 in, respective1340134ly, 42 and 65%
yield (Scheme 1).
properties of polypyridine transition-metal complexes,
such as intense and well-defined absorption bands in the
visible region, long-lived metal-to-ligand charge-transfer
excited state obtained in high quantum yields, and a rich
redox activity, make possible the sensitization of photoin-
2
duced electron- and/or energy-transfer processes. Such
highly desirable features have stimulated efforts to con-
struct covalent assemblies having bpy subunits linked to
macrocyclic and macrobicyclic structures, thereby pro-
3–5
ducing photoactive hemi-cage or cage complexes. The
6
7
encapsulation of lanthanides and ruthenium using
ligands built around bipyridine-based fragments has been
achieved. In some cases, these complexes could not be ob-
tained by the classical method of complexation [L + metal
precursor] due to steric congestion around the complex-
ation sites. However, the encapsulated metal complexes
often could be obtained in two steps by first preparing the
podand complex followed by subsequent closing of the
pseudo-macrocyclic cavity by a cyclization reaction.8
Our recent work related to calixarenes modified with bpy
9
10
subunits, and the study of their lanthanide complexes,
prompted us to design polybipyridine ligands based on
acyclic and macrocyclic polyamines. This work is moti-
vated by the opportunity to construct or engineer ligands
bearing more than six discrete coordination sites, with a
Scheme 1
preorganized cavity, that could offer improved stabiliza- For the synthesis of the 1,4,7-triazacyclononane deriva-
tion of encapsulated lanthanide ions. The latter are known tive 5, three equivalents of compound 1 in methanol are
11
to be stabilized by eight or nine coordination sites. The added dropwise to a 1:1 H O/MeOH mixture containing
2
choice at the 5,5'-substituted bpy was deduced from pre- NaOH (3 equiv) and the triazamacrocycle (1 equiv). Dur-
vious work, where it has been shown clearly that high lu- ing the course of reaction, the pH becomes neutral and
minescence quantum yields could be obtained with eu- pure compound 5 is recovered by filtration after a couple
ropium while, for stereoelectronic reasons, the 6,6'-posi- of hours (74%). When applied to the other cyclic amines,
1
2
tions are less suitable.
this method gave lower yields of alkylated products.

1
340
Papers
SYNTHESIS
(
i) for 5: NaOH/H O/MeOH, r.t., 10 min or 6–8: Na CO /CH CN, 80 °C, 1–3 d
2 2 3 3
Scheme 2
Consequently, additional ligands were prepared by a one-
pot reaction starting from 1 and the polyazamacrocycles
(
cyclen, hexacyclen) or with acyclic aromatic benzylic
polyamines [1,3-bis(aminomethyl)benzene, 2,6-bis(ami-
nomethyl)pyridine, 6,6'-bis(aminomethyl)-2,2'-bipyr-
idine, 2,9-bis(aminomethyl)-1,10-phenanthroline] in the
presence of sodium or potassium carbonate (excess), in
anhydrous acetonitrile, under a controlled atmosphere
(
Schemes 2–4, Table 1). Ligands 10–13 were obtained in
27–58% yields after purification by alumina column chro-
matography. The commercially available polyamines in
their protonated form (sulfate or chloride as counterion) or
purified by recrystallization of their protonated form were
neutralized before handling using a DOWEX ion-ex-
change resin.
Complexation Properties of Tripode 5 and Hexapode
9
with Iron(II) Salts
6
Polypyridine d -transition metal complexes have been
widely used as photosensitizers in catalytic systems [e.g.
reduction of water to hydrogen or reduction of carbon di-
1
6
oxide to carbon monoxide]. In some cases, the catalyti-
cally active species are generated by photolabilization of
1
7
a ligand in organic or hydroorganic solvants. This limits
the lifetime of the catalytic system and severely restricts
potential applications of these systems. Moreover, iron
tris(bipyridine) complexes have previously been utilized
1
8
to catalyze thermal H O oxidation. Here also turnover
2
numbers are restricted by instability of the complexes due
Scheme 3

September 1998
SYNTHESIS
1341
to decoordination of the bpy ligands. The use of hemi-
cage ligands might increase the chemical stability of these
complexes. In order to test the ability of these ligands to
form stable complexes we chose to complex tripode 5 and
hexapode 9 with iron(II) salts. Low-spin mono- and dinu-
clear complexes were formed which could be studied by
NMR, enabling us to explore the coordination properties
of these new podands. Reaction of 5 and 9 with
Fe(ClO ) •6 H O in a dichloromethane/methanol mixture
4
2
2
gave an instantaneous deep-violet color and precipitation.
Based on analytical data, the resultant complexes were
formulated as [Fe(5)](ClO ) and [Fe (9)](ClO ) . The
4
2
2
4 4
FAB-mass spectrum of the mononuclear [Fe(5)](ClO4)2
complex recorded in H3-nitrobenzyl alcohol exhibits an
intense molecular peak at m/z = 930 [M + H], while a peak
at m/z = 1759 [M – ClO ] is observed for the correspond-
4
ing dinuclear [Fe (9)](ClO ) complex. No contamination
2
4 4
from polymeric structures (or monomeric complex in the
case of the dinuclear species) was observed. Both molec-
ular peaks exhibit the expected isotopic profile and the
mass spectra show peaks corresponding to the successive
loss of perchlorate anions. In order to increase the solubil-
1
ity of these complexes, so as to facilitate H NMR studies,
the hexafluorophosphate salts were prepared. Reaction of
5
and 9 with one and two equivalents of FeSO •7 H O,
4 2
respectively, gave water-soluble, deep-violet complexes.
After exchange of the counterion using an aqueous solu-
Scheme 4
Table 1. Selected Spectroscopic Data for Precursors and Polybipyridine Ligands.
+
1
a
UV-visb
Com-
pound
Yield
(%)
Molecular
Formula
FAB -MS
H NMR δ, J (Hz)
(m-NBA)
λ (nm)
–1
–1
[
ε (M cm )]
M+H]+
bpy-CH3
2.43 (s, 3H)
–
bpy-CH2
H6 or 6'-bpy
H6'or 6-bpy
(π → π , bpy)
260 (23,000)
256 (18,900)
*
[
3
4
42
65
C H N O Br
295.0/297.0
372.8/374.8/
4.64 (s, 2H)
4.71 (s, 4H)
8.54 (s, 1H)
8.32 (s, 1H)
1
2
11
2
2
4
C H N O Br
8.50 (d, 2H, J = 1.6)
1
2
10
2
2
2
376.8
5
74
C H N
676.0
2.34 (s, 9H)
3.62 (s, 6H)
8.56 (d, 3H,
J = 1.6)
8.46 (d, 3H,
J = 1.4)
285 (56,600)
4
2
45
9
4
4
6
7
60
38
C H N O
772.3
901.3
2.60 (s, 9H)
4.00 (s, 6H)
3.47 (s, 8H)
8.66 (s, 3H)
8.59 (d, 4H,
8.49 (s, 3H)
8.46 (d, 4H,
260 (54,100)
284 (76,000)
4
2
45
9
6
C H N
60 12
2.37 (s, 12H)
5
6
4
4
J = 1.6)
J = 2.1)
8
9
65
30
58
C H N O
6
1029.3
1351.6
865.3
2.55 (s, 12H)
2.38 (s, 18H)
2.31 (s, 12H)
3.78 (s, 8H)
3.52 (s, 12H)
3.62 (s, 8H)
8.60 (s, 4H)
8.49 (s, 6H)
8.64 (d, 4H,
8.42 (s, 4H)
8.46 (s, 6H)
8.43 (d, 4H,
253 (73,500)
285 (109,000)
286 (81,300)
5
6
60 12
C H N
90 18
8
4
1
1
1
1
0
1
2
3
C H N
56 52 10
4
4
J = 1.5)
J = 1.6)
47
45
27
C H N
51 11
866.3
943.5
967.5
2.34 (s, 12H)
2.34 (s, 12H)
2.37 (s, 12H)
3.69 (s, 8H)
3.76 (s, 8H)
3.82 (s, 8H)
8.65 (d, 4H,
8.44 (d, 4H,
286 (83,400)
286 (95,000)
286 (90,200)
5
5
4
4
J = 1.6)
J = 1.3)
C H N
54 12
8.69 (d, 4H,
8.46 (d, 4H,
6
0
4
4
J = 1.2)
J = 0.6)
C H N
54 12
8.75 (s, 4H)
8.47 (s, 4H)
6
2
a
Performed in CD OD for 3, in DMSO for 4, in D O (t-BuOH as internal standard) for 6, 8 and in CDCl for 5, 7, 9–13.
3
2
3
b
Measured in CH OH for 3, 6, in CH OH/H O (1 : 4) for 4, 8 and in CH Cl for 5, 7, 9–13, at r.t.
3
3
2
2
2

1
342
Papers
SYNTHESIS
2
0
tion of KPF and purification by chromatography, the clic tris(bpy) cryptates or in double-helicates generated
6
complexes [Fe(5)](PF ) 14 and [Fe (9)](PF ) 15 were by pseudo-tetrahedral copper(I) cations.21 Furthermore,
obtained in modest yield and characterized by H NMR, the significant upfield shift of these CH -bpy H-atoms (by
FAB , UV-vis spectroscopy, cyclic voltammetry, and el- ca. 0.6 ppm) indicates that they lie in the deshielding re-
6
2
2
6 4
1
2
+
emental analysis.
gion of the bpy subunits. It is notable that a strong com-
plexation effect is also found for the non-aromatic ring
H-atoms which split into three well-defined multiplets
Complexation of the metal rigidifies the ligands and in-
duces drastic changes in the NMR shifts. In the case of
[1:2:1 integration] with a significant upfield shift in the
[
Fe(5)](PF ) , the aromatic part of the spectrum is influ-
6 2
range of 0.2 to 0.9 ppm. This effect is due to steric crowd-
ing which distorts the flexible 9N3 polyazamacrocycle to
such a degree that non-equivalence of these macrocyclic
H-atoms is observed. As expected, no complexation effect
was observed on the methyl H-atoms.
enced by the iron center, and in particular the signals of
the 6,6'-hydrogens (ortho from the coordinative nitro-
gens) are shifted downfield by ∆δ = 0.57 and 1.65 for each
signal. This strong shielding is due to octahedral complex-
ation of the bpy subunits forcing the H-atom ortho to the
chelating N-atom to lie above the plane of a second bpy Identical effects are observed in the case of
unit. In contrast, less pronounced shifts are observed for [Fe (9)](PF ) , with the exception that one of the aromatic
2
6 4
1
9
the signals of the other aromatic H-atoms. The CH -bpy H-atoms is much more upfield shifted (ca. 3 ppm). Most
2
signal, seen as a singlet in the free ligand at δ = 3.62, is probably, this effect is due to severe steric constraints
shifted to 4.18, but does not split into a clear AB pattern which force one of the ortho H-atoms to reside very close
upon complexation. This is due to the fact that the CH2 to the shielding zone of one bpy unit, as can be inferred
H-atoms are equivalent in the complex and do not point from examination of space-filling models of 15. Looking
towards the chiral center of C symmetry which has a he- closely at these models one can see clearly that the two met-
3
lical twisting around the central 9N3 macrocycle/Fe axis. al ions are lodged on opposite sides of the plane defined
Splitting of the parent CH -bpy H-atom signals that span by the hexaazacyclooctadecane macrocyclic ring, each ion
2
a macrobicycle or two bpy fragments into a well-defined being surrounded by three bpy units. This structural ar-
AB pattern has been observed previously in macrobicy- rangement is illustrated in Scheme 5 for compound 15a.
Scheme 5

September 1998
SYNTHESIS
1343
The space-filling model of this geometrical arrangement
shows that the coordination sphere provided by three al-
ternating N-atoms of the ring and by three alternating bpy
units is well suited for coordination of Fe(II). It can also
be seen that an alternative geometrical arrangement exists
for the iron(II) species which utilizes three contiguous bpy
units on each side of the plane (15b in Scheme 5). This
latter arrangement would not be suitable for a dinuclear
complex, but should exclusively form the mononuclear
species. These simple considerations and the well-defined
NMR spectra exclude fluxional processes in solution and
reflect the high stability of these complexes.
acetone-d6 (2.06), DMSO (2.6), D2O (t-BuOH as internal standard)
4.8); δ(C) in ppm rel. to the solvent CDCl (77.0). MS: FAB, positive
(
3
mode ZAB-HF-VG-analytical apparatus in a H3-nitrobenzyl alcohol
m-NBA) or thioglycerol for 14, 15. Electrochemical studies were
(
made by cyclic voltammetry with a conventional 3-electrode system
using a BAS 50-W Instruments potentiostat. The working electrode
was a highly polished platinum disc while the counter electrode was
a Pt wire. A saturated calomel reference electrode was separated from
the solution by a glass frit. Solutions contained the electrode-active
substrate (ca. 10–3 M) and 0.1 M Bu NPF as supporting electrolyte.
4
6
All solutions were deoxygenated by purging with Ar prior to elec-
trolysis.
Alumina (Merck), Na CO (Prolabo), K CO (Prolabo), hexacyclen-
2
3
2
3
trisulfate (Aldrich), 1,3-bis(aminomethyl)benzene (Aldrich),
Fe(ClO ) •6 H O (Aldrich), 3-chloroperoxybenzoic acid 50% dis-
Both complexes exhibit a well-defined and intense metal-
to-ligand charge transfer UV-vis absorption band at low
4
2
2
persed in water (Lancaster) were used as received. CH CN used in the
3
–
1
–1
reactions was distilled over P O under anhyd argon. Triazacy-
energy λmax = 503 nm (ε = 6,900 M cm ) and λ
5
=
4
10
max
23
23
–
1
–1
clononane,
tetraazacyclododecane,
2,6-bis(aminomethyl)pyri-
14 nm (ε = 14, 200 M cm ), respectively, for 14 and
dine,24 6,6'-bis(aminomethyl)-2,2'-bipyridine, and 2,9-bis(amino-
24
15. The high-energy absorption bands are typical of ligand-
25
methyl)-1,10-phenanthroline were prepared according to literature
centered transitions (Table 2). These electronic absorption
spectra, measured in acetonitrile, compare well with the
procedures.
2+ 22
corresponding spectrum recorded for [Fe(bpy) ] . Cy-
5-(Bromomethyl)-5'-methyl-2,2'-bipyridine 1,1'-Dioxide (3):
A solution of m-CPBA (50% dispersed in water, 9.00 g, 25.7 mmol)
3
clic voltammetry shows that the mononuclear iron(II)
complex 14 (E1/2 = 1.08 V) and the dinuclear iron(II) com-
plex 15 (E1/2 = 1.06 V) are oxidized at the same potential,
but at a value significantly higher than the corresponding
in CHCl (150 mL) was added dropwise over 3 h to a stirred cold
3
solution of 5-(bromomethyl)-5'-methyl-2,2'-bipyridine (1) (2.26 g,
8
.58 mmol) in CHCl (500 mL). The mixture was stirred at r.t. for 3 d.
3
The solution was filtered though an alumina column eluting with
2
+
[
Fe(bpy) ] complex. As might be expected, both iron(II)
3
CHCl . After evaporation of the solvent, the precipitate was purified
3
centers are electronically isolated in 15.
by chromatography (alumina, CH Cl /MeOH with a gradient of
2
2
MeOH 0–5%) (alumina, CH Cl /MeOH 98:2, R 0.42). The recrystal-
2
2
f
The synthetic protocol described herein provides access to
a novel family of polydendate ligands bearing three, four,
or six bipyridine or bipyridine N,N’-dioxide subunits co-
valently linked to acyclic and macrocyclic polyamines.
Some of these ligands are suitable for the preparation of
stable, low-spin, and redox-active iron(II) complexes. The
presence in ligands 11, 12, 13 of a potential central coor-
dinative bridging unit [pyridine, bipyridine, phenanthro-
line] is especially appealing for the future preparation of
polynuclear transition-metal complexes exhibiting special
properties, such as molecular recognition of cations.
lization from CH Cl /hexane affording the pure white compound;
yield: 1.06 g (42%).
2
2
C H N O Br calcd
C
48.84
48.62
H
3.76
3.59
N
9.49
9.40
12
11
2
2
(295.13)
found
1
H NMR (CD OD): δ = 8.54 (s, 1H), 8.32 (s, 1H), 7.58 (m, 4H), 4.64
3
(
s, 2H, CH -Br), 2.43 (s, 3H, CH ).
2
3
IR (KBr): ν = 3034 (s), 2977 (m), 2920 (m), 1654 (m), 1604 (m), 1491
(s), 1445 (m), 1399 (s), 1282 (s)(νNO), 1248 (s), 1208 (m), 1176 (s),
–
1
1
134 (m), 1089 (m), 1047 (m), 1024 (s), 985 (m) cm .
UV-vis (MeOH): λmax (ε, M–1 cm ) = 260 (23,000), 223 (35,100) nm.
MS (FAB): m/z = 295.0/297.0 (M + H) , 279.0/281.0 (M – O + H).
–1
+
5,5'-Bis(bromomethyl)-2,2'-bipyridine 1,1'-Dioxide (4):
UV-vis spectra: Shimadzu UV-260 or Perkin–Elmer Lambda 5. FT-
IR spectra: Brucker IFS 25 spectrometer; KBr pellets. NMR spectra:
at r.t.; Bruker-SY-200 or AC-200 (200.1 ( H) or 50.3 MHz ( C));
A similar procedure was used to that for the preparation of 3: m-
CPBA (50%, 1.51 g, 4.38 mmol,), 5,5'-bis(bromomethyl)-2,2'-bipyri-
dine (2) (0.5 g, 1.46 mmol), CHCl3 (150 mL). After chromatography
(alumina, CH2Cl2/MeOH with a gradient of MeOH 0–10%) (alumina,
1
13
δ(H) in ppm rel. to residual CHCl in CDCl (7.25), CD OD (3.30),
3
3
3
Table 2. Selected Spectroscopic Data for the Iron Complexes
+
UV-visa
Compound
Yield
%)
Molecular
Formula
FAB -MS
E1/2 (V)
λ (nm), [ε (M–1 cm )]
–1
[∆E (mV)]
b
(
(thioglycerol)
p
[
Fe (bpy)3]2+
520 (8,050)c
+0.96 [80]c
1
4
5
91
93
C H N FeP F
876.4 (M-PF )+
503 (6,900),
292 (83,900), 252 (64,800)
+1.08 [93]
–1.54 [88], –1.75 [72]
4
2
45
9
2
12
6
731.4 (M-2PF6)
+
1
C H N Fe P F
1897.1 (M-PF ) , 1752.1
514 (14,200), 296 (107,600),
249 (69,000)
+1.06 [93]
–1.49 [64], –1.68 [85]
8
4
90 18
2
2
24
6
(
M-2PF ), 1607.1 (M-
6
3
PF ), 1462.2 (M-4PF )
6
6
a
Measured in CH CN at r.t.
3
b
Determined in CH CN+ n-Bu NPF (0.1 M) using SCE as reference electrode, and ferrocene as internal reference, E = + 0.34 V with a
3
4
6
1/2
separation between anodic and cathodic peak potentials ∆E = 82 mV. No compensation was made for internal cell resistance
According to ref. 22.
p
c

Papers
CH Cl /MeOH 98:2, R 0.63), the analytically pure compound was
SYNTHESIS
1
344
stirred 30 min at 80°C. Whereupon solid 1 (0.385 g, 1.46 mmol) was
added to the mixture, which was heated under reflux for 1 d. The re-
action was quenched with water and the organic product extracted
with CH Cl (3 × 100 mL). The organic layers were dried (MgSO ),
2
2
f
obtained; yield: 0.358 g (65%).
C H N O Br calcd
C
38.53
38.29
H
2.69
2.41
N
7.49
7.29
3
12
10
2
2
2
(374.03)
found
2
2
4
the solvent was then removed under vacuum. The crude product was
chromatographed (alumina, CH Cl /MeOH 99:1, R = 0.25), leading
1
4
H NMR (DMSO-d ): δ = 8.50 (d, 2H, J = 1.6 Hz), 7.66 (d, 2H, J =
6
3
4
2
2
f
7
.9 Hz), 7.49 (dd, 2H, J = 8.0, J = 1.6 Hz), 4.71 (s, 4H, CH -Br).
2
to the pure product; yield: 0.11 g (38%).
IR (KBr): ν = 3053 (s), 2976 (m), 1646 (m), 1604 (m), 1490 (s), 1433
C H N
calcd
found
C
74.64
74.53
H
6.71
6.68
N
18.65
18.61
4
(
m), 1380 (s), 1277 (s)(νNO), 1217 (s), 1180 (s), 1135 (m), 1047 (m),
56 60 12
–
1
(901.18)
1
1
025 (s) cm .
UV-vis (MeOH/H O 1:4): λmax (ε, M–1 cm ) = 256 (18,900), 226
–1
H NMR (CDCl ): δ = 8.59 (d, 4H, J = 1.6 Hz), 8.46 (d, 4H, J =
4
2
3
3
4
(
39,200) nm.
2.1 Hz), 8.23 (4 line-m, 8H), 7.75 (dd, 4H, J = 8.2, J = 1.9 Hz), 7.56
(dd, 4H, J = 8.2, J = 1.9 Hz), 3.47 (s, 8H, bpy-CH -N), 2.72 (s, 16H,
+
3
4
MS (FAB): m/z = 372.8/374.8/376.8 (M + H) , 356.8/358.8/360.8 (M
2
–
O + H).
N-CH -), 2.37 (s, 12H, CH ).
2
3
13
1
C-{ H} NMR (CDCl ): δ = 155.1, 153.7, 149.7, 149.5, 137.6,
3
1
,4,7-Tris[(5'-methyl-2,2'-bipyridin-5-yl)methyl]-1,4,7-triazacy-
137.3, 134.7, 132.9, 120.6, 120.4, 57.3, 53.2, 18.3.
clononane (5):
IR (KBr): ν = 2916 (m), 2796 (m), 1596 (m), 1553 (m), 1465 (s), 1365
–1
To a solution of 1 (0.59 g, 2.23 mmol) in MeOH (10 mL) at r.t. was
added dropwise 1,4,7-triazacyclononane (0.085 g, 0.745 mmol) in
water (5 mL) containing NaOH (0.09 g, 2.23 mmol) and MeOH
(m), 1026 (m) cm .
–1
UV-vis (CH Cl ): λ
(ε, M–1 cm ) = 284 (76,000), 239 (56,400),
2
2
max
217 (31,200) nm.
MS (FAB): m/z = 901.3 (M + H) , 719.3 (M + H-CH -bpy-CH ).
+
(5 mL). After 10 min, a precipitate had formed, and the suspension
2
3
was stirred until the pH approached neutrality (ca. 3 h). The white
solid was filtered off, washed with water (3 × 10 mL) and Et O
1,4,7,10-Tetrakis[(5'-methyl-1,1'-dioxo-2,2'-bipyridin-5-yl)meth-
yl]-1,4,7,10-tetraazacyclododecane (8):
A similar experimental procedure as for the preparation of 5 was
used: 1,4,7,10-tetraazacyclododecane (0.025 g, 0.146 mmol), 3
2
(
3 × 25 mL), and dried under vacuum to give the pure product; yield:
.365 g (74%).
C H N
0
calcd
found
C
74.64
74.41
H
6.71
6.51
N
18.65
18.49
4
4
2
45
9
(
0.175 g, 0.598 mmol), Na CO (0.016 g, 1.460 mmol), CH CN
(
1
675.88)
2
3
3
(
10 mL). (alumina, CH Cl /MeOH, 94:6, R 0.43); yield: 0.096 g (65%).
4
2
2
f
H NMR (CDCl ): δ = 8.56 (d, 3H, J = 1.6 Hz), 8.46 (d, 3H, J =
3
3
4
C H N O •2 H O calcd
C
63.14
63.05
H
6.06
5.98
N
15.78
15.57
1
(
.4 Hz), 8.24 (3 line-m, 6H), 7.72 (dd, 3H, J = 8.1, J = 1.9 Hz), 7.56
56 60 12
8
2
3
4
(1029.18 + 36.03)
found
dd, 3H, J = 8.1, J = 1.9 Hz), 3.62 (s, 6H, bpy-CH -N), 2.79 (s, 12H,
2
1
N-CH -), 2.34 (s, 9H, CH ).
H NMR (D O + t-BuOH) δ = 8.60 (s, 4H), 8.42 (s, 4H), 7.74 (m,
2
3
2
13
1
C-{ H} NMR (CDCl ): δ = 155.1, 153.6, 149.9, 149.5, 137.6,
16H), 3.78 (s, 8H, bpy-CH -N), 2.95 (s, 16H, N-CH ), 2.55 (s, 12H,
3
2
2
1
37.3, 135.2, 133.1, 120.4, 120.3, 60.2, 55.5, 18.3.
CH3).
IR (KBr): ν = 2920 (m), 2802 (m), 1596 (m), 1553 (m), 1462 (s), 1360
IR (KBr): ν = 3048 (m), 2976 (m), 2926 (m), 2796 (m), 1646 (m),
–
1
(
m), 1092 (m), 1026 (m) cm .
1492 (m), 1453 (m), 1405 (m), 1354 (m), 1276 (s), 1252 (m), 1178
–
1
–1
–1
UV-vis (CH Cl ): λ (ε, M cm ) = 285 (56,600), 239 (41,500),
(m), 1079 (m), 1048 (m), 1026 (s) cm .
2
2
max
(ε, M–1 cm ) = 253 (72,900), 217
–1
2
17 (22,700) nm.
UV-vis (MeOH/H O 1:4): λ
2
max
+
MS (FAB): m/z = 676.0 (M + H) , 494.0 (M + H-CH -bpy-CH ).
(126,600) nm.
2
3
+
MS (FAB): m/z = 1029.3 (M + H) , 1013.5 (M – O + H), 997.5 (M –
1
1
,4,7-Tris[(5'-methyl-1,1'-dioxo-2,2'-bipyridin-5-yl)methyl]-
,4,7-triazacyclononane (6):
2O + H), 981.5 (M – 3O + H), 965.2 (M – 4O + H), 949.5 (M – 5O +
H).
A stirred solution of anhyd CH CN (10 mL) containing 1,4,7-triaza-
3
cyclononane (0.007 g, 0.053 mmol) and Na CO (0.056 g,
2
3
0
.530 mmol) was heated at 80°C. After 30 min, solid 3 (0.050 g,
1,4,7,10,13,16-Hexakis[(5'-methyl-2,2'-bipyridin-5-yl)methyl]-
1,4,7,10,13,16-hexaazacyclooctadecane (9):
0
.169 mmol) was added to the mixture and the suspension was heated
under reflux for 3 d. The solvent was removed under vacuum. The
crude product was purified by chromatography (alumina, CH Cl /
A
solution of 1,4,7,10,13,16-hexaazaoctadecane (0.11 g,
0.415 mmol) and Na2CO3 (0.88 g, 8.3 mmol) in anhyd CH3CN
(10 mL) was stirred 30 min at 80°C. Whereupon, solid 1 (0.765 g,
2.91 mmol) was added and the mixture was heated under reflux for
1 d. The reaction was quenched with water and the organic products
were extracted with CH2Cl2 (3 × 100 mL). The organic layers were
2
2
MeOH with a gradient of MeOH 0 to 10%) (alumina, CH Cl /MeOH
2
2
9
4:6, R 0.51). Recrystallization of the precipitate by slow diffusion
f
of hexane into a CH Cl /MeOH solution afforded the white analyti-
2
2
cally pure compound; yield: 0.024 g (60%).
dried (MgSO ) and the solvent removed under vacuum. After short
C H N O •2 H O calcd
C
62.44
62.26
H
6.11
5.94
N
15.60
15.20
4
42
45
9
6
2
filtration over an alumina column using a mixture of CH Cl /MeOH
2
2
(771.88+36.03)
found
9
9:1, R 0.2, a twofold recrystallization in CH Cl /hexane led to the
f
2
2
1
H NMR (D O + t-BuOH): δ = 8.66 (s, 3H), 8.49 (s, 3H), 7.70 (m,
2
pure product; yield: 0.17 g (30%).
1
2H), 4.00 (s, 6H, bpy-CH -N), 3.12 (s, 12H, N-CH ), 2.60 (s, 9H,
2
2
C H N
90 18
calcd
found
C
74.64
74.45
H
6.71
6.60
N
18.65
18.47
3
84
CH3).
(1351.75)
IR (KBr): ν = 3034 (s), 2977 (m), 2920 (m), 1654 (w), 1604 (w), 1491
1
(
s), 1445 (m), 1399 (s), 1282 (s), 1248 (s), 1208 (m), 1176 (s), 1134
H NMR (CDCl3): δ = 8.49 (s, 6H), 8.46 (s, 6H), 8.21 (d, 12H, J =
–
1
(m), 1089 (m), 1047 (m), 1024 (s), 985 (m) cm .
8.0 Hz), 7.60 (m, 12H), 3.52 (s, 12H, bpy-CH2), 2.68 (s, 24H, N-CH2-),
2.38 (s, 18H, CH3).
–
1
–1
UV-vis (MeOH): λmax (ε, M cm ) = 260 (54,100), 220 (87,100) nm.
MS (FAB): m/z = 772.3 (M + H) , 756.3 (M – O + H), 740.4 (M – 2O
+
13
1
C NMR-{ H} (CDCl3): δ = 155.0, 153.4, 149.4, 149.3, 137.2,
+
H), 724.3 (M – 3O + H).
137.1, 134.5, 132.9, 120.4, 120.2, 56.4, 52.4, 18.2.
IR (KBr): ν = 2918 (w), 2790 (w), 1597 (w), 1554 (m), 1463 (s),
–1
1
1
,4,7,10-Tetrakis[(5'-methyl-2,2'-bipyridin-5-yl)methyl]-
,4,7,10-tetraazacyclododecane (7):
1049 (m) cm .
–1
UV-vis (CH Cl ): λ
(ε, M–1 cm ) = 285 (109,000), 240 (79,000),
2
2
max
A solution of 1,4,7,10-tetraazacyclododecane (0.056 g, 0.325 mmol)
and Na CO (0.344 g, 3.25 mmol) in anhyd CH CN (10 mL) was
217 (43,500) nm.
MS (FAB): m/z = 1351.6 (M + H) , 1169.5 (M + H-CH -bpy-CH ).
+
2
3
3
2
3

September 1998
SYNTHESIS
1345
13
1
1
,3-Bis[bis(5'-methyl-2,2'-bipyridin-5-yl)aminomethyl)]benzene
C NMR-{ H} (CDCl ): δ = 158.3, 155.4, 153.4, 149.5, 137.3,
3
(10):
134.0, 133.2, 122.8, 120.4, 119.4, 59.2, 55.2, 18.2.
To a mixture of 1,3-bis(aminomethyl)benzene (0.05 g, 0.367 mmol)
and Na CO (0.86 g, 8 mmol) in anhyd CH CN (10 mL), was added
IR (KBr): ν = 2925 (m), 1707 (w), 1595 (m), 1571 (m), 1553 (m),
–1
1467 (s), 1361 (m), 1027 (w) cm .
2
3
3
(ε, M–1 cm ) = 286 (95,000), 240 (58,000),
–1
solid 1 (0.423 g, 1.6 mmol). This blend was heated at 80°C for 12 h,
protected from moisture. The reaction was then quenched with water
and the organic products extracted with CH Cl . After drying the or-
UV-vis (CH Cl ): λ
2 2 max
216 (34,000) nm.
MS (FAB): m/z = 943.5 (M + H) , 759.4 (M – CH -bpy-CH ).
+
2
2
2
3
ganic layers (MgSO ), the solvent was removed under vacuum fol-
4
lowed by chromatography (alumina, EtOAc/hexane 9:1, R 0.4). The
pure title compound was then obtained; yield: 0.183 g (58%).
2,9-Bis[bis(5'-methyl-2,2'-bipyridin-5-yl)aminomethyl]-1,10-
phenanthroline (13):
f
To anhydrous CH CN (10 mL) containing 2,9-bis(aminomethyl)-
C H N
52 10
calcd
found
C
77.75
77.71
H
6.06
5.93
N
16.19
16.11
4
3
56
1
1
,10-phenanthroline (0.03 g, 0.134 mmol) and K CO3 (0.26 g,
.35 mmol), was added solid 1 (0.156 g, 0.6 mmol). After heating the
(865.106)
2
1
4
H NMR (CDCl ): δ = 8.64 (d, 4H, J = 1.5 Hz), 8.43 (d, 4H, J =
3
mixture for 12 h at 80°C, water (10 mL) was added, the organic com-
pound was extracted with CH Cl , and the organic layers were dried
3
4
1
.6 Hz), 8.24 (4 line-m, 8H), 7.79 (dd, 4H, J = 8.2, J = 2.1 Hz), 7.52
3
4
2
2
(dd, 4H, J = 8.2, J = 1.8 Hz), 7.37 (s, 2H, H -Ar), 7.28 (br s, 3H, H-Ar),
6
(
MgSO ). Chromatography (alumina, CH Cl /MeOH 99:1, R 0.15)
4
2
2
f
3
.62 (s, 8H, bpy-CH ), 3.59 (s, 4H, Ar-CH -N), 2.31 (s, 12H, CH ).
C-{ H} NMR (CDCl ): δ = 155.3, 153.4, 149.5, 138.8, 137.2,
2
2
3
gave the pure compound; yield: 0.035 g (27%).
1
3
1
3
C H N
62 54 12
calcd
found
C
76.99
76.57
H
5.63
5.35
N
17.38
17.04
1
34.1, 133.1, 128.9, 128.5, 127.6, 120.4, 57.9, 55.1, 18.2.
(967.202)
IR (KBr): ν = 2920 (m), 1706 (w), 1594 (m), 1552 (m), 1466 (s),
–
1
1
1
359 (m), 1027 (m) cm .
H NMR (CDCl ): δ = 8.75 (s, 4H), 8.47 (s, 4H), 8.27 (m, 12H), 7.3
3
UV-vis (CH Cl ): λ
(ε, M–1 cm ) = 286 (81,300), 241 (57,000),
–1
(d, 4H, J = 6.5 Hz), 7.73 (s, 2H), 7.57 (d, 4H, J = 6.5 Hz), 4.23 (s,
4H, phen-CH -N-), 3.82 (s, 8H, N-CH -bpy), 2.37 (s, 12H, CH ).
3
3
2
2
max
2
17 (30,200) nm.
2
2
3
+
13
1
MS (FAB): m/z = 865.3 (M + H) , 681.2 (M – CH -bpy-CH ), 500.2
C NMR-{ H} (CDCl ): δ = 159.9, 155.4, 153.5, 149.7, 137.6, 137.4,
2
3
3
(
M – 2(CH -bpy-CH ) + 2H).
136.7, 134.1, 133.3, 127.9, 126.1, 122.2, 120.5, 60.3, 55.7, 18.3.
2
3
IR (KBr): ν = 2923 (m), 1708 (w), 1595 (m), 1552 (s), 1466 (s), 1374
–1
2
,6-Bis[bis(5'-methyl-2,2'-bipyridin-5-yl)aminomethyl]pyridine
(m), 1027 (m) cm .
–1
(
1
11):
(0.422 g, 1.6 mmol) was poured into a stirring mixture of 2,6-
bis(aminomethyl)pyridine (0.05 g, 0.364 mmol) and Na CO (0.78 g,
UV-vis (CH Cl ): λ
230 (59,400) nm.
(ε, M–1 cm ) = 286 (90,200), 239 (56,600),
2
2
max
+
MS (FAB): m/z = 967.5 (M + H) , 785.4 (M – CH -bpy-CH ).
2
3
2
3
7
1
.3 mmol) in anhyd CH CN (10 mL), and then heated at 80°C for
2 h, protected from moisture. The reaction was quenched with water,
3
{
1,4,7-Tris[(5'-methyl-2,2'-bipyridin-5-yl)methyl]-1,4,7-triazacy-
the organic matter extracted with CH Cl , dried (MgSO ), and the
residue obtained after solvent evaporation was purified by chroma-
tography (alumina, EtOAc, R 0.2). The pure desired product was ob-
tained; yield: 0.15 g (47%).
2
2
4
clononane}iron(II) Hexafluorophosphate [Fe(5)](PF ) (14):
To a solution of 5 (0.02 g, 0.029 mmol) in CH Cl (5 mL) was added
a solution of Fe(SO ) 7 H O (0.009 g, 0.032 mmol) in MeOH
6
2
2
2
f
•
4 2 2
(5 mL). A deep-violet solution was instantaneously formed, and the
C H N
51 11
calcd
found
C
76.28
76.05
H
5.94
5.74
N
17.79
17.54
4
mixture was stirred 3 h. After addition of KPF6 (0.016 g,
0.087 mmol), slow evaporation of the solvent resulted in the precipi-
tation of a crude red powder which was purified by column chroma-
tography (alumina, CH CN) (alumina, CH CN/H O/sat. aq KNO ,
55
(866.093)
1
4
H NMR (CDCl ): δ = 8.65 (d, 4H, J = 1.6 Hz), 8.44 (d, 4H, J =
3
3
4
3
3
2
3
1
.3 Hz), 8.24 (4 line-m, 8H), 7.81 (dd, 4H, J = 8.1, J = 2.1 Hz), 7.55
3
4
3
50:15:1, R 0.33). Recrystallization of the complex (CH CN/toluene)
f
3
(
(
dd, 4H, J = 8.1, J = 2.1 Hz), 7.39 (d, 2H, J = 7.0 Hz, H3,5-pyr), 7.36
d, 1H, J = 7.0 Hz, H -pyr), 3.77 (s, 4H, py-CH -N), 3.69 (s, 8H, bpy-
3
gave the titled compound as red needles; yield: 0.025 g (91%).
4
2
CH ), 2.34 (s, 12H, bpy).
C42H45N9FeP2F12 calcd
C
49.38
49.15
H
4.44
4.19
N
12.34
12.19
3
2
13
1
C-{ H} NMR (CDCl ): δ = 158.5, 155.5, 153.5, 149.5, 137.5,
(1021.66)
found
3
1
3
1
37.2, 134.1, 133.3, 121.3, 120.6, 59.7, 55.7, 18.4.
H NMR (acetone-d ): δ = 8.70 (d, 3H, J = 8.3 Hz), 8.68 (d, 3H, J =
.3 Hz), 8.29 (dd, 3H, J = 8.3, J = 1.6 Hz), 8.11 (dd, 3H, J = 8.3, J
6
IR (KBr): ν = 2918 (m), 1708 (w), 1595 (m), 1553 (m), 1461 (s), 1360
3
4
3
4
8
–
1
m), 1030 (m) cm .
4
(
=
1.6 Hz), 8.02 (s, 3H), 6.79 (d, 3H, J = 1.6 Hz), 4.18 (ls, 6H), 3.57
(ε, M–1 cm ) = 286 (83,400), 241 (55,000),
–1
UV-vis (CH Cl ): λ
2
2
max
(m, 3H), 3.24 (m, 6H), 3.04 (m, 3H), 2.32 (s, 9H).
IR (KBr): ν = 2824 (m), 1609 (m), 1470 (s), 1396 (m), 1109 (s) (PF ),
1062 (m), 837 (m), 739 (s) cm .
2
16 (30,700) nm.
6
+
MS (FAB): m/z = 866.3 (M + H) , 682.2 (M – CH -bpy-CH ).
–1
2
3
(ε, M–1 cm ) = 503 (6,900), 292 (83,900),
–1
UV-vis (CH CN): λ
3
max
2
52 (64,800) nm.
6
,6'-Bis[bis(5'-methyl-2,2'-bipyridin-5-yl)aminomethyl]-2,2'-bi-
+
MS (FAB): m/z = 876.4 (M – PF ) , 731.4 (M – 2PF ).
6
6
pyridine (12):
To anhyd CH CN (15 mL) containing 6,6'-bis(aminomethyl)-2,2'-bi-
3
{
1
1,4,7,10,13,16-Hexakis[(5'-methyl-2,2'-bipyridin-5-yl)methyl]-
,4,7,10,13,16-hexaazacyclooctadecane}diiron(II) Hexafluoro-
phosphate [Fe (9)](PF ) (15):
pyridine (0.05 g, 0.233 mmol) and Na CO (0.5 g, 4.6 mmol) was
2
3
added solid 1 (0.27 g, 1.0 mmol). After heating the mixture for 12 h
at 80°C, water (10 mL) was added, and the organic compound was
extracted with CH Cl . Flash chromatography (silica gel, CH Cl /
2
6 4
To a solution of 9 (0.025 g, 0.018 mmol) in CH Cl (5 mL) was added
a solution of Fe(SO ) •7 H O (0.011 g, 0.040 mmol) in MeOH
2
2
2
2
2
2
4
2
2
MeOH 95:5, R 0.4) afforded the pure compound; yield: 0.1 g (45%).
f
(5 mL). A deep-violet solution was instantaneously formed, and the
C H N
calcd
found
C
76.41
76.23
4
H
5.77
5.41
N
17.82
17.55
60
54 12
mixture was stirred for 3 h. After filtration of the resulting solution over
Celite, KPF (0.020 mg, 0.108 mmol) was added and the solvent slowly
removed under vacuum. The resulting precipitate was recovered by
centrifugation, washed with water, and purified by chromatography
(alumina, CH CN) (alumina, CH CN/H O/sat. aq KNO 50;15;1, R
(943.179)
6
1
4
H NMR (CDCl ): δ = 8.69 (d, 4H, J = 1.2 Hz), 8.46 (d, 4H, J = 1.2
3
3
4
Hz), 8.22 (m, 10H), 7.85 (dd, 4H, J = 8.1, J = 1.2 Hz), 7.78 (d, 2H,
3
3
4
3
J = 8.1 Hz), 7.57 (dd, 4H, J = 8.1, J = 1.2 Hz), 7.48 (d, 2H, J = 8.1
Hz), 3.86 (s, 4H, bpy-CH -N), 3.76 (s, 8H, N(-CH -bpy) ), 2.34 (s,
3
3
2
3
f
0.24). Recrystallization of the deep-red powder from an CH CN/tolu-
2
2
4
3
1
2H, CH3).
ene mixture, gave 15 as red needles; yield: 0.032 g (93%).

Papers
C H N Fe P F calcd
SYNTHESIS
1
346
C
49.38
49.11
3
H
4.44
4.26
N
12.34
12.25
3
(7) Belser, P.; De Cola, L.; von Zelewsky, A. J. Chem. Soc., Chem.
Commun. 1988, 1057.
84
90 18
2 4 24
(2043.32)
found
1
De Cola, L.; Barigeletti, F.; Balzani, V.; Belser, P.; von Ze-
lewsky, A.; Vögtle, F.; Ebmeyer, F.; Grammenudi, S. J. Am.
Chem. Soc. 1989, 111, 4662.
H NMR (CD CN): δ = 8.66 (d, 2H, J = 8.4 Hz), 88.64 (d, 2H, J =
3
8
.4 Hz), 8.33 (m, 8H), 7.93 (m, 12H), 7.89 (s, 2H), 7.88 (s, 2H), 7.66
(s, 2H), 7.62 (s, 2H), 7.50 (s, 2H), 5.71 (s, 2H), 4.89 (m, 12H), 4.06
(m, 4H), 3.58 (m, 4H), 3.41 (m, 4H), 2.86 (m, 8H), 2.52 (m, 4H), 2.35
(s, 9H), 2.26 (s, 9H).
Ebmeyer, F.; Vögtle, F. Chem. Ber. 1989, 122, 1725.
(
8) Grammenudi, S.; Vögtle, F. Angew. Chem., Int. Ed. Engl. 1986,
25, 1122.
IR (KBr): ν = 2927 (m), 1631 (m), 1473 (s), 1396 (m), 1317 (w), 1110
–
1
(9) Ulrich, G.; Ziessel, R. Tetrahedron Lett. 1994, 34, 6299.
Ulrich, G.; Ziessel, R.; Manet, I.; Guardigli, M.; Sabbatini, N.;
Fraternali, F.; Wipff, G. Eur. J. Chem. 1997, 3, 1815.
(10) Sabbatini N.; Guardigli M.; Manet I.; Ungaro R.; Casnati A.; Fi-
scher C.; Ziessel R.; Ulrich G. New J. Chem. 1995, 19, 137.
(
s, PF ), 843 (s), 619 (m), 561 (m) cm .
6
–
1
–1
UV-vis (CH CN): λ
(ε, M cm ) = 514 (14,200), 296 (107,600),
max
3
2
49 (69,000) nm.
+
MS (FAB): m/z = 1897.1 (M – PF ) , 1752.1 (M – 2PF ), 1607.1 (M
6
6
–
3PF ), 1462.1 (M – 4PF ).
6
6
(
11) Alexander, V. Chem. Rev. 1995, 95, 273.
(12) Prodi, L.; Maestri, M.; Ziessel, R.; Balzani, V. Inorg. Chem.
1
991, 30, 3798.
(
(
(
1) Balzani, V.; Juris, A.; Venturi, M.; Campagna, S.; Serroni, S.
Chem. Rev. 1996, 96, 759.
2) Harriman, A.; Ziessel, R. J. Chem. Soc., Chem. Commun. 1996,
Ziessel, R.; Maestri, M.; Prodi, L.; Balzani, V.; Dorsselaer, A.
V. Inorg. Chem. 1993, 32, 1237.
(
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