Structural development of free or coordinated 4′-(4-pyridyl)-2, 2′:6′,2′-terpyridine ligands through N-alkylation: New strategies for metallamacrocycle formation

Article abstract of DOI:10.1002/chem.200600069

A series of N-alkylated derivatives of [Ru(pytpy)₂]² (pytpy = 4′-(4-pyridyl)-2,2′:6′,2″-terpyridine) has been synthesised and characterised. These include both model and functionalised complexes that complement previously reported ir

Full text of DOI:10.1002/chem.200600069

DOI: 10.1002/chem.200600069
Structural Development of Free or Coordinated 4’-(4-Pyridyl)-2,2’:6’,2’’-
terpyridine Ligands through N-Alkylation: New Strategies for
Metallamacrocycle Formation
[
a]
[a]
[a]
Edwin C. Constable,* Emma L. Dunphy, Catherine E. Housecroft,
[
a]
[a]
[a]
[a]
William Kylberg, Markus Neuburger, Silvia Schaffner, Emma R. Schofield, and
[
a, b]
Christopher B. Smith
Abstract: A series of N-alkylated de-
(bromomethyl)phenyl]methane leads
to the formation of a [2+2] ruthenama-
crocycle. Related ferramacrocycles
could not be accessed by this route,
and instead were prepared in two steps
by first reacting bis[4-(bromomethyl)-
phenyl]methane or 4,4’-bis(bromo-
2
+
rivatives of [Ru
A
C
H
T
R
E
U
N
G
(pytpy) ] (pytpy=4’-
2
(
4-pyridyl)-2,2’:6’,2’’-terpyridine)
has
been synthesised and characterised.
These include both model and func-
tionalised complexes that complement
previously reported iron(ii) analogues.
A
H
R
U
G
Keywords: alkylation
cycles iron metallacycles
ruthenium
·
hetero-
of pytpy, and then treating the resulting
bis(N-alkylated) product with iron(ii)
salts.
A
H
R
U
G
·
·
·
2
+
Reaction of [Ru
A
C
H
T
R
E
U
N
G
(pytpy) ] with bis[4-
2
Introduction
the formation of metallamacrocycles (often entropically fav-
[5–22]
oured under conditions of high dilution)
and metalla-
[22–28]
Multitopic ligands that contain two or more 2,2’:6’,2’’-terpyr-
idine (tpy) metal-binding domains are now well established
as building-blocks for the assembly of supramolecular sys-
A
H
R
U
G
Designing spacers between the metal-bonding
domains that possess appropriate structural coding is one
strategy for driving the reaction towards metallamacrocycle
rather than polymer formation. This has been demonstrated
by Newkome and co-workers in both the assembly of molec-
[
1,2]
tems.
also commonly used, their disadvantage is that they give
rise to chiral (D and L) [cis-M(bpy) X ] and [M(bpy) ] spe-
cies. In contrast, tpy ligands substituted at the 4’-position, or
symmetrically on the outer rings, give achiral [M(tpy) ] com-
While bipyridine (bpy) metal-binding domains are
[
3]
[13]
[7,9,10,14]
A
H
R
U
G
A
H
E
N
ular triangles and hexagons.
Conversely, the use of
2
2
3
flexible spacers that impose little restriction in conforma-
A
H
R
U
G
tional space, appears to favour metallapolymer forma-
2
[4]
[22–28]
plexes. Metal-directed self-assembly based on the coordi-
nation chemistry of ditopic tpy ligands has received signifi-
cant recent attention. In most cases, metallamacrocycles are
formed by the reaction of the ditopic tpy ligand with metal
ions, but a significant problem is the competition between
tion.
In our own work, we have demonstrated the for-
mation of a range of metallamacrocycles with less well pre-
[15–19,21]
organised ligands,
but have also shown that the 788
angle between the least-squares planes of the two central
pyridine rings in tpySStpy preorganises the ligand for the
formation of a [4+4] metallamacrocycle upon reaction with
[20]
iron(ii) salts. In this report, we focus attention on the use
of 4’-(4-pyridyl)-2,2’:6’,2’’-terpyridine (pytpy) as a building
block in supramolecular chemistry.
[
a] Prof. Dr. E. C. Constable, E. L. Dunphy, Prof. Dr. C. E. Housecroft,
W. Kylberg, M. Neuburger, Dr. S. Schaffner, Dr. E. R. Schofield,
Dr. C. B. Smith
Department of Chemistry, University of Basel
Spitalstrasse 51, 4056 Basel (Switzerland)
Fax : (+41)61-267-1005
[29]
The pytpy ligand exhibits versatile coordination chemis-
try, forming mononuclear complexes with one or two pen-
[
29–37]
[38,39]
A
H
R
U
G
coordination polygons,
and
E-mail: edwin.constable@unibas.ch
[40,41]
The pendant pyridine donor has
[
b] Dr. C. B. Smith
been used to control the self-assembly of monolayers on
platinum, the monolayers being investigated by scanning
Current address:
School of Biomedical, Biomolecular and Chemical Sciences
University of Western Australia, Crawley
Perth, W.A. 6009 (Australia)
[31,42,43]
tunnelling microscopy and electrochemical techniques.
Some years ago, we presented a preliminary report of a
4600
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 4600 – 4610

FULL PAPER
bromide in CH CN at reflux proceeded smoothly to give,
3
after workup, 3[PF ] as a pink solid in 68% yield. The elec-
A
H
R
U
G
6 4
strategy for the construction of a [2+2] metallamacrocycle
containing {Fe(tpy) } motifs based on the N-alkylation of
ACHTREUNG
2
[5]
the pendant pyridine ring in coordinated pytpy. We have
also described a series of N-alkylation reactions of the 4’-
2
+
pyridyl groups in [M
A
H
R
U
G
of functional substituents to generate a series of metallaviol-
[
29,30,44]
ogens analogous to viologens.
kylation of free and coordinated pytpy has potential for use
in a range of applications. Williams and co-workers have ob-
served that iridium(iii)–bis(tpy) complexes containing 4’-(3-
N-methylpyridyl) or 4’-(4-N-methylpyridyl) substituents
The strategy of N-al-
ACHTREUNG
A
C
H
T
R
E
U
N
G
ACHTREUNG
[45]
function as luminescent sensors for chloride ions,
Loeb has shown that the N-alkylation of pytpy by 1-bromo-
-(4,4’-bipyridinium)ethane bromide leads to an effective
building block for the axle of a [2]-rotaxane that has the ca-
and
trospray (ES) mass spectrum exhibited peak envelopes at
+
2+
m/z=1339 ([MꢀPF ] ) and 597 ([Mꢀ2PF ] ) and a base
6
6
2
+
2
peak in the mass spectrum at m/z=362 ([Ru
A
T
E
N
Each envelope showed the correct distribution of isotopo-
[46]
1
13
pability of binding metal ions.
In an elegant piece of
logues. The H and C NMR spectra of 3[PF ] confirmed a
A
H
R
U
G
6 4
work, Kurth has reported the assembly of a pytpy-based co-
symmetrical product and were fully assigned by using
COSY, HMBC, and HMQC techniques. In terms of the sig-
nals assigned to the pytpy protons, the H NMR spectrum is
[47]
balt(ii)–metallaviologen
functional component of electrochromic thin films.
that has been incorporated as a
[48–50]
1
This
[
30]
diversity of applications of N-alkylated pytpy ligands leads
us to present a full account of our recent activities in this
area.
very similar to that of [Ru(N-Mepytpy) ][PF ] , with only
A
T
E
N
2 6 4
3
B
2C
3C
signals for H , H and H showing significant differences
2
+
4+
between 2
and 3
(Table 1). Of these, the signal for
3
C
proton H undergoes the largest change, moving 0.53 ppm
to higher frequency. Confirmation that N-alkylation had oc-
curred at both pendant pyridine rings came from the results
Results and Discussion
of a single-crystal structure determination of the complex.
2
+
1
Model N-alkyl derivatives of [Ru
A
H
R
U
G
Crystals of 3
A
H
R
U
G
A
H
R
U
G
2
6
4
3
2
3
3
ously reported the preparation, characterisation and reactiv-
ity of a series of complexes formed by the N-alkylation of
slow diffusion of diethyl ether into a solution of 3[PF ] in
A
C
H
T
R
E
U
N
G
6 4
acetonitrile/acetone . Although the crystal quality was poor,
it was sufficient to permit the gross structural features of
2
+
2+ [29,44]
2+
[Fe
A
C
H
T
R
E
U
N
G
(pytpy) ] (1 ).
These studies confirmed that 1
2
4
+
behaves in an analogous manner to 4,4’-bipyridine, undergo-
A
H
R
U
G
A
H
R
U
G
ing N-alkylation reactions at both non-coordinated nitrogen
atoms to produce metallaviologens. A crystallographic
ion is presented in Figure 1(top), and selected bond lengths
and angles are given in the caption. The bond lengths and
[5]
study of the N-benzylated derivative [Fe(N-PhCH pytpy) ]-
angles within the {Ru
A
H
R
U
G
2
2
2
[44]
ꢀ
A
C
H
T
R
E
U
N
G
[PF ]
illustrated that the spatial properties of [Fe(N-
the four [PF6] ions, one has each F atom disordered over
two sites, each with 50% occupancy. One of the acetone sol-
vent molecules is disordered over two positions (1:1), with
one site coinciding with the position of the 33% occupancy
acetonitrile molecule. In the solid state, two types of interac-
6
4
4
+
PhCH pytpy) ] render it and its related complexes ideal
2
2
building blocks for the formation of metallamacrocyclic
[
51]
complexes from cyclic bis(4,4’-bipyridinium) salts.
have now extended our investigation of model N-alkylated
We
2
+
2+ [30]
4+
complexes to the reactions of [Ru
range of alkylating agents.
A
H
R
U
G
tion between 3 ions are important. Firstly, rows of cations
2
run parallel to the crystallographic a axis, with the cations in
each row off-set from one another to facilitate p-stacking
between pyridine rings containing atoms N4 and N6 of adja-
cent cations (shortest contacts between planes=3.5 Š).
Complementing this arrangement is one in which cations
align parallel to the b axis (Figure 1bottom) so that there
2
+
We have previously shown that whereas 1 readily reacts
with MeI to give [Fe(N-Mepytpy)2] (N-Mepytpy=4’-(N-
methyl-4-pyridinio)-2,2’:6’,2’’-terpyridine), N-methylation of
requires an excess of [Me O][BF ] in CH CN under
reflux. The reaction of 2[PF ] with an excess of benzyl
4
+
2
+
2
A
H
R
U
G
3
4 3
[30]
A
H
R
U
G
6 2
Chem. Eur. J. 2006, 12, 4600 – 4610
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4601

E. C. Constable et al.
1
Table 1. H NMR spectroscopic data [d in ppm] for CD
3
CN solutions of pytpy and symmetrical ruthenium(ii) and iron(ii) complexes. See schematic dia-
grams and Schemes 2 and 3 for compound numbering and ring labelling.
3
A
4A
5A
6A
3B
2C
3C
H
H
H
H
H
H
H
[
a]
pytpy
ruthenium(ii) complexes
8.72
7.99
7.47
8.74
8.80
8.77
7.83
[
a]
2
[
A
C
H
T
R
E
U
N
G
[PF
6
]
2
8.66
8.68
8.70
8.72
8.70
8.72
8.70 (8.72, H
8.69
8.55
7.97
8.017.23
8.00
7.99
8.00
8.017.23
8.00 (8.04, H )
8.017.24
7.20
7.43
9.07
8.72
8.97
8.14
[
a]
Ru(N-Mepytpy)
2
]
A
C
H
T
R
E
U
N
G
[PF
6
]
4
7.43
7.45
3
9
9.1 8.95
9.1 9.04
3
4
5
6
7
8
1
A
C
H
T
R
E
U
N
G
[PF
[PF
[PF
[PF
[PF
[PF
6
6
6
6
6
6
]
]
]
]
]
]
4
4
4
4
4
4
7.23
7.22
7.22
7.43
7.43
7.43
9.14
9.19
9.16
8.78
9.18 (8.79, H
8.76
9.09
9.18
9.11
8.77
8.83
8.78
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
3
F
4F
5F
6F
3E
A
C
H
T
R
E
U
N
G
)
7.22 (7.52, H
7.44
6.63
)
7.43 (8.74, H
9.1 9.03
7.28
)
)
9.17
9.00
8.80
8.75
A
C
H
T
R
E
U
N
G
5
6
A
C
H
T
R
E
U
N
G
[PF
6
]
8
7.54
9.12
iron(ii) complexes
[
b]
1
[
1
1
A
C
H
T
R
E
U
N
G
[BF
4
]
2
8.63
8.63
8.50
8.44
7.92
7.96
7.80
7.44
7.09
7.13
6.99
6.52
7.17
7.18
7.01
6.99
9.23
9.27
9.16
9.19
9.03
9.13
9.14
9.03
8.23
8.82
8.76
8.78
[c]
Fe(N-PhCH
2
2 6 4
pytpy) ][PF ]
A
C
H
T
R
E
U
N
G
4
5
A
C
H
T
R
E
U
N
G
[PF
6
6
]
]
8
8
ACHTREUNG
[PF
[
a] Reference [30]. [b Reference [29]. [c] Reference [44].
[52,53]
are weak edge-to-face interactions
matic rings (H521ꢀcentroid of ring containing atom C22=
.1Š; angle C52-H52 1- centroid =155.48). These interactions
between benzyl aro-
3
control the relative orientations of the benzyl groups in the
crystalline solid. Interestingly, similar edge-to-face interac-
tions between benzyl groups are absent in the solid-state
[44]
structure of the iron(ii) analogue and, as a result, the rela-
tive orientations of the benzyl groups differ between the
iron(ii) and ruthenium(ii) complexes.
2
+
A second N-alkylated derivative of 2 was prepared by
the reaction of 2[PF ] with an excess of 2-bromomethyl-
AHCTREUNG
6
2
naphthalene in CH CN under reflux. The reaction was
3
monitored by TLC and had reached completion after 24 h.
After chromatographic workup 4
yield. The electrospray mass spectrum of 4[PF ] showed
6 4
A
H
R
U
G
A
H
R
U
G
+
+
peak envelopes at 1439 ([MꢀPF ] ), 1294 ([Mꢀ2PF ] ),
6
6
+
+
1
152 ([Mꢀ(napCH )ꢀ2PF ] ), 867 ([Ru
and 722 ([Ru(pytpy) ] ), each with the correct isotope dis-
2
tribution. The H NMR spectrum of 4[PF ] is similar to that
of 3[PF ] , and both the H and C NMR spectra confirmed
A
H
R
U
G
A
H
R
U
G
A
C
H
T
R
E
U
N
G
2
6
+
A
H
R
U
G
1
A
H
R
U
G
6 4
1
13
A
H
R
U
G
6 4
the presence of a symmetrical, homotopic complex. In addi-
1
tion to the H NMR signals listed in Table 1, a singlet at d=
6
.07 ppm was assigned to the CH group, and signals at d=
2
8
.17, 8.07, 8.01 and 7.66 ppm to the naphthalene protons.
The electronic absorption spectra of solutions of the two
complexes 3
A
H
R
U
G
A
T
E
N
6
4
[
30]
[
Ru(N-Mepytpy) ]
A
H
R
U
G
A
H
R
U
G
2
6
4
red shift of the MLCT absorption from 488 nm in 2[PF ] to
A
C
H
T
R
E
U
N
G
6 2
[
30]
5
5
07 nm in [Ru(N-Mepytpy) ]
A
H
R
N
A
H
R
N
2
6
4
13 nm in 4[PF ] . Each complex also shows a series of in-
A
H
R
U
6 4
tense bands in the UV region that are assigned to ligand-
centred p* p transitions; the absorption at 224 nm for
4
+
Figure 1. Top: Molecular structure of the 3 ion in the complex 3
(CH CO·0.3CH
CN. Selected bond parameters: Ru1ꢀN1=2.064(5),
Ru1ꢀN2=1.966(5), Ru1ꢀN3=2.066(5), Ru1ꢀN4=2.073(5), Ru1ꢀN5=
A
H
R
U
G
6 4
[PF ] ·2
!
A
C
H
T
R
E
U
N
G
3
)
2
3
A
H
R
U
G
A
H
R
U
1
.970(5), Ru1ꢀN6=2.080(5), C8ꢀC18=1.484(8), N7ꢀC21=1.500(9),
Both 3
ied by using cyclic and differential pulse voltammetries. We
have previously reported that on going from [Ru(tpy) ]-
[PF ] to [Ru(pytpy) ][PF ] , there is a small shift to positive
A
H
R
U
G
A
T
E
N
6
4
C35ꢀC45=1.493(10), N8ꢀC48=1.486(9) Š; N1-Ru1-N2=79.0(2), N2-
Ru1-N3=78.1(2), N4-Ru1-N5=78.6(2), N5-Ru1-N6=79.1(2), N7-C21-
C22=114.8(7), N8-C48-C49=109.8(8)8. Bottom: Part of one chain of cat-
ions that pack along the b axis, supported by weak edge-to-face aromatic
interactions.
ACHTREUNG
2
A
H
R
U
G
A
H
E
N
ACHTREUNG
6
2
2
6 2
2
+
3+
potential (+0.92 to +0.95 V) for the Ru /Ru oxidation
4602
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 4600 – 4610

Metallamacrocycles
FULL PAPER
process, indicating that the 4-pyridyl substituent is very
the pytpy unit in 6
(Table 1), and signals in the range d=4.68–ꢁ1.3 ppm were
assigned to the (CH ) Br chain. The C NMR spectrum
A
H
T
E
U
[PF ] was similar to that in 5
A
C
H
T
R
E
U
N
G
[PF ]
6
4
6 4
[30]
weakly electron-withdrawing. Methylation of the pendant
pyridyl groups results in a further shift to +1.03 V, consis-
tent with an increase in the electron-withdrawing effect on
1
3
2
10
confirmed the symmetry of the system and was fully as-
signed by using HMQC and HMBC techniques.
+
[30]
going from pytpy to [N-Mepytpy] .
For 3
A
H
R
U
G
ACHTREUNG
6
4
4
+
4+
A
C
H
T
R
E
U
N
G
4
A
C
H
T
R
E
U
N
G
[PF ] , metal-centred oxidation processes were observed at
Complexes 5 and 6 possess pendant electrophilic sites
6
4
+
1.01 and +1.02 V, respectively, illustrating that the benzyl
and are potential building blocks for metallamacrocyclic or
and naphthylmethyl substituents behave in a similar manner
polymeric systems. An alternative strategy that has already
4
+
[5–28]
to the methyl substituent in [Ru(N-Mepytpy)2] . Each of
[PF ] and 4[PF ] also exhibits several ligand-centred re-
been widely exploited
is to design building blocks that
A
C
H
T
R
E
U
N
G
3
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
are terminated in metal-binding domains, and we have now
6
4
6 4
2
+
ductions; in the case of 3
while 4
[PF ] shows a reversible ligand reduction at ꢀ0.89 V
and two quasi-reversible processes at ꢀ1.48 and ꢀ1.96 V.
A
H
R
U
G
coupled this approach with the N-alkylation of 2 to gener-
6
4
A
C
H
T
R
E
U
N
G
ate a new class of functionalised metallasupramolecules. The
6
4
reaction of 2[PF ] with an excess of 4’-(4-bromomethyl-
A
H
R
U
G
6 2
phenyl)-2,2’:6’,2’’-terpyridine in CH CN under reflux was
3
2
+
Functionalised N-alkyl derivatives of [Ru
A
H
R
U
G
monitored by spot TLC and was judged to be complete
2
the successful preparation and isolation of the N-alkylated
after 64 h; complex 7[PF ] was isolated as a pink solid. The
A
H
R
U
G
6 4
4
+
4+
complexes 4 and 5 , we turned our attention to N-al-
highest mass peak in the ES mass spectrum came at m/z=
2
+
+
A
C
H
T
R
E
U
N
G
kylated derivatives of 2 containing pendant functionalities.
1334 and was assigned to the ion [MꢀCH C H tpyꢀ2PF ] ;
2
6
4
6
4
+
4+
+
The strategy for the formation of complexes 5 , 6 and
a peak at m/z=632 ([pytpyCH C H tpy] ) was also ob-
2 6 4
4
+
4+
4+
2+
7
was the same as for 3 and 4 . In each case, 2 was
served. Other dominant peaks in the mass spectrum arose
+
+
treated with an alkylating agent in large excess to ensure
from [Ru
722) and [Ru(pytpy) ] (m/z=362, base peak). When re-
2
A
H
R
U
G
A
H
R
U
G
A
H
R
U
G
6
2
+
the formation of the N,N’-dialkylated products. In the case
4
+
4+
of the preparation of 5 and 6 , the excess of 1,4-bis(bro-
momethyl)benzene or 1,10-dibromodecane also ensured that
reaction occurred at only one of the bromo groups, thus pro-
cording the H NMR spectrum of 7
A
T
E
N
to add a small amount of K CO to the solution in the NMR
2
3
tube to prevent protonation of the pendant tpy nitrogen
atoms; in the absence of base, only broad resonances, indi-
4
+
4+
viding complexes 5
and 6
with pendant electrophilic
1
groups. The reactions of 2
A
H
R
U
G
cative of protonation, were observed. The H NMR spec-
6
2
2
+
benzene or 1,10-dibromodecane were significantly slower
than with benzyl bromide or 2-bromomethylnaphthalene,
and reactions times >48 h were required to achieve com-
plete alkylation. The progress of the reactions was moni-
tored by spot TLC. After only 24 h, two pink products were
present; prolonged heating of the reaction mixture in reflux-
ing acetonitrile led to the gradual disappearance of the spe-
trum confirmed that both pyridine rings in 2 had been al-
kylated, with two tpy environments being apparent, and the
signals were assigned from the COSY spectrum. While one
4
+
set of signals for the tpy protons in 7 resembled those for
4
+
4+
4+
4+
3
, 4 , 5 and 6 , the second set was diagnostic of a
3
B
5A
non-coordinated tpy ligand; signals for protons H , H and
H
The C NMR spectrum of 7[PF ] also clearly indicated the
6
A
are significantly perturbed upon coordination (Table 1).
1
3
cies with the lower R value, and an increase in the amount
A
H
R
U
G
f
6 4
of the other fraction. We assume that the lower R fraction
presence of two tpy environments, and the spectrum was
fully assigned by using HMQC and HMBC techniques.
In the present work, the conditions for the synthesis of
f
2
+
is the monoalkylated derivative of 2 . After workup,
[PF ] and 6[PF ] were isolated in 35 and 74% yields, re-
A
C
H
T
R
E
U
N
G
5
A
C
H
T
R
E
U
N
G
ACHTREUNG
6
4
6 4
[30]
spectively.
In the ES mass spectrum of 5[PF ] , no parent ion nor
6 4
A
H
R
U
G
A
H
R
U
G
in that
6
2
A
H
R
U
RuCl ·3H O and pytpy were heated in ethane-1,2-diol for
3
2
ions with characteristic Br-containing isotopic distributions
could be observed. The dominant peak envelopes in the
one rather than three hours. Under these conditions (and
after workup), a second product was isolated which was
+
mass spectrum arose from the fragments [Ru
A
H
R
U
G
A
H
R
U
G
identified as 8
the alkylation of 2
ed in only 8% yield, 8
a functionalised N-alkyl derivative of [Ru
FAB mass spectrum of 8[PF ] exhibited peaks at m/z=1247
A
H
R
U
G
2
6
+
2+
(
(
m/z=867), [Ru
m/z=362, base peak). In contrast, the ES mass spectrum of
[PF ] exhibited peaks at m/z=1597 and 1451 assigned to
A
C
H
T
R
E
U
N
G
(pytpy) ] (m/z=720) and [Ru
A
H
R
U
G
2
A
H
R
U
2
+
6
[
A
C
H
T
R
E
U
N
G
A
H
R
U
G
6
4
+
+
MꢀPF ] and [Mꢀ2PF ] , respectively, in addition to the
ACHTREUNG
6
6
6 4
+
+
1
13
base peak at m/z=362 assigned to [Ru
A
T
U
G
([MꢀPF ] ) and 1102 ([Mꢀ2PF ] ). The H and C NMR
6
6
peak at m/z=529 arising from [Br
A
H
R
U
G
spectra of 8[PF ] were consistent with the formation of a
A
T
E
N
2
10
6 4
topic distribution of each peak matched those of the simu-
symmetrical product and the spectra were fully assigned by
using COSY, HMQC and HMBC methods. The data in
Table 1show that the signals assigned to the pytpy protons
appear at chemical shifts close to those of the other N-al-
1
lated spectrum. The H NMR spectrum of 5[PF ] confirmed
A
H
R
U
G
6 4
the expected molecular symmetry with a single set of signals
for the pytpy unit with chemical shifts close to those found
4
+
4+
for 3 and 4 (Table 1). In addition, singlets at d=5.89
ACHTREUNG
and 4.65 ppm were assigned to the NCH and CH Br pro-
A
C
H
T
R
E
U
N
G
[PF ] ,
2
2
6 4
tons, and an AB pattern (d=9.11 and 8.78 ppm) to the 1,4-
phenylene protons. The H NMR spectroscopic signature for
6
A
H
R
U
G
A
H
R
U
G
ACHTREUNG
6
4
6
4
6
4
3
1
of the complexes 3
A
H
R
U
G
A
H
R
U
G
6
4
Chem. Eur. J. 2006, 12, 4600 – 4610
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4603

E. C. Constable et al.
ed an MLCT absorption in the range 508–512 nm, and a
series of intense bands in the UV region assigned to ligand-
!
centred p* p transitions. Each complex was redox active
and was studied by CV and DPV methods. The complexes
A
C
H
T
R
E
U
N
G
5
A
C
H
T
R
E
U
N
G
[PF ] , 6
A
C
H
T
R
E
U
N
G
[PF ] , 7
A
C
H
T
R
E
U
N
G
[PF ] and 8[PF ] exhibited ruthenium-
A
H
R
U
G
6
4
6
4
6
4
6 4
centred oxidations at +1.01, +0.99, +1.01 and +1.02 V, re-
spectively, showing little variation from the behaviour of the
model complexes. Each complex exhibited a series of
ligand-based reduction processes, which were typically
quasi-reversible or irreversible.
2
+
Metallamacrocycle formation: The ready N-alkylation of 1
[
44]
2+
and 2 led us to apply this strategy to the formation of
iron(ii) and ruthenium(ii)-containing metallamacrocyclic
complexes by reaction with bis(alkylating) reagents. By
2
+
analogy with the reactions of 1
2
+
3
Scheme 1. The 1:1 reaction of 1 and 9: i) 9, CH CN, reflux. The ring la-
2
+
and 2 with benzyl bromide, we
chose the dibromo derivatives 9
belling is that used for NMR spectroscopic assignments.
2
+
2+
and 10 to react with 1 and 2
in the hope of forming [2+2] met-
allamacrocycles.
order to achieve the desired [2+2] metallamacrocyclic com-
plex were unsuccessful. We therefore turned to the alterna-
tive strategy outlined in Scheme 2 involving alkylation of
the free pytpy ligand. The reaction between pytpy and
Initially, we attempted a one-
step assembly process by the
2
+
direct reaction of 1 with 9 in re-
fluxing CH CN. Complex 1[PF ]
6 2
either 9 or 10 in CH CN at reflux followed by precipitation
3
A
H
R
U
G
of the products as hexafluorophosphate salts, resulted in the
3
was added to a solution of 9 over
a six hour period and then heating
was continued for a further 72 hours. When the resulting
dark blue solution was analysed by TLC, one major blue
component was observed and was shown (see below) to be
formation of 12
spectively. Solvent choice is important; attempts to prepare
12[PF ] in EtOH, iPrOH or DMF resulted in yields of 0, 28
or 37%, respectively. The MALDI-TOF mass spectra of
12[PF ] and 13[PF ] each showed a peak assigned to
A
H
R
U
G
A
H
R
U
G
6
2
ACHTREUNG
6
2
A
H
R
U
G
A
H
R
U
G
6
2
+
1
1
1
A
C
H
T
R
E
U
N
G
[PF ] (Scheme 1). Chromatographic separation of the re-
[MꢀPF ] (m/z=947 and 959, respectively). The H NMR
6
6
6
action mixture led to the isolation of several minor fractions,
but none proved to be the target [2+2] macrocyclic product.
By using a 2:1molar ratio of
spectra of the two compounds were similar, with the excep-
tion of the alkyl region. For 12[PF ] , this exhibited a singlet
A
H
R
U
G
6 2
2
+
1
/9 in the reaction, 11[PF ]
A
H
R
U
G
6 6
could be isolated in 23% yield.
1
The H NMR spectrum of 11-
A
C
H
T
R
E
U
N
G
[PF ]
(assigned by using
6
6
COSY and NOESY techni-
ques) confirmed the presence
of two different coordinated
tpy environments. Signals for
the pendant pyridine protons
also indicated two different en-
vironments, one N-alkylated
[30]
and one not.
cal studies
11[PF ] exhibits one iron-cen-
tred oxidation process at
Electrochemi-
showed that
A
C
H
T
R
E
U
N
G
ACHTREUNG
6
6
+
0.79 V, and a second process
+1.04 V, the origin of which
at
ACHTREUNG
we have not elucidated. Re-
duction processes are dominat-
ed by an absorption peak at ꢁ
ꢀ
1.2 V.
Scheme 2. Reaction steps for the formation of [2+2] iron-containing macrocyclic complexes: i) 9 or 10,
Attempts to react 11[PF ]
A
H
R
U
G
6 6
CH CN, reflux; ii) Fe
A
H
R
U
G
3
4
2
2
3
3
with another equivalent of 9 in
signments.
4604
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 4600 – 4610

Metallamacrocycles
FULL PAPER
at d=5.83 ppm for the NCH , while 13
A
H
R
U
G
mation of a macrocyclic complex. Significantly greater
2
6 2
4A
singlets at d=5.72 and 4.04 ppm (relative integrals 2:1) as-
signed to NCH and the CH group between the D rings
values for {d
A
H
R
U
G
A
H
E
N
(complex)} of +0.52 ppm for H
5
A
and +0.92 ppm for H are observed on going from ligand
2
2
2
+
(
Scheme 2), respectively. A single set of tpy proton signals
13 to complex 15 (both in CD CN). The origin of this
3
for each compound confirmed the expected molecular sym-
metry. The assignment of the pyridine protons H and H
increased shift to lower frequency can be traced to the
change in shape of the macrocyclic cavity when the addi-
tional CH2 groups are introduced into the backbone of
C2
C3
was made by NOE experiments.
2
+
2+
2+
2+
The N-alkylated species 12 or 13 are sufficiently flexi-
ble bis(tpy) ligands to enable the formation of metalla-
macrocycles when treated with iron(ii). Since competitive
ligand on going from 12 to 13 . Figure 2 shows modelled
8
+
8+
A
C
H
T
R
E
U
N
G
structures of 14 and 15 , and illustrates the elongation of
the cavity. The modelled structures suggest that two pyridine
rings face each other across the macrocyclic cavity, elonga-
tion of which results in the pyridine rings coming closer to-
gether and the evolution of possible p-stacking interactions.
The pyridine ring centroid–-centroid distances are ꢁ7.5 Š in
ACHTREUNG
polymer formation was expected, reactions were carried out
at high dilution to optimise the formation of metallamacro-
A
C
H
T
R
E
U
N
G
cyclic products. Solutions of 12
A
H
E
N
[PF ]
or 13
A
H
R
U
G
6
2
ꢀ
4
ꢀ3
ꢀ3
(
(
ꢁ10 moldm
in
CH CN)
and
Fe(BF ) ·6H O
ACHTREUNG
3
4
2
2
ꢀ
4
8+
8+
ꢁ10 moldm in CH CN) were added simultaneously to
14 , and ꢁ3.6 Š in 15 . The presence of a through-space
3
3A 6A
a stirred mixture of CH CN and CH OH (1:1) over a period
interaction between protons H and H of different {Fe-
(tpy) } units in 14[PF ] and in 15[PF ] was confirmed by
3
3
of four days at room temperature. The solution developed a
blue colour, which deepened during the reaction period. At-
tempts to separate the products by chromatography on silica
led to decomposition, and fractional precipitation was used
A
H
R
U
A
H
E
N
ACHTREUNG
2
6
8
6 8
ROESY experiments. The room-temperature solution
1
H NMR spectrum of each of 14
A
H
R
U
G
A
H
R
U
G
6
8
that the two terminal pyridine rings of each tpy unit were
equivalent and indicated that there was rotation of each {Fe-
to separate 14
A
C
H
T
R
E
U
N
G
[PF ] and 15[PF ] from residual precursors
A
T
E
N
6
8
6 8
and any polymeric material. Initially, all complexes in the
reaction mixture were precipitated as hexafluorophosphate
salts by adding aqueous NH PF . These salts were dissolved
A
T
E
N
(tpy) } unit on the NMR timescale. Variable-temperature
2
1
H NMR spectra of solutions of 14
A
H
R
U
G
A
T
E
N
6
8
tonitrile were recorded over a temperature range of 295–
228 K. Apart from some broadening of the signals and slight
shifting to lower frequency, no significant changes were ob-
served.
4
6
in CH CN and a few drops of saturated aqueous KNO
3
3
were added causing a deep blue precipitate to form. Analy-
sis by thin-layer chromatography revealed this material to
be intractable and it was therefore assumed to be polymeric.
Both iron(ii) macrocyclic complexes were electrochemi-
Dropwise addition of further saturated aqueous KNO to
cally active. Complexes 14
A
H
R
U
G
A
T
E
N
3
6
8
the filtrate led to additional precipitate. Again, this was ana-
lysed by TLC, and the process was repeated until a blue pre-
cipitate that was mobile on silica was obtained. Careful rep-
centred oxidation processes at +0.85 and +0.86 V, respec-
tively. These potentials are similar to those reported for N-
2
+
[44]
2+
alkylated derivatives of [Fe
A
H
R
U
G
.
Only one Fe /
2
3
+
etition of this process resulted in 14
collected in 35 and 16% yields, respectively.
The highest mass peak in the ES mass spectrum of
[PF ] appeared at m/z 1291 and was assigned to the frag-
A
H
R
U
G
A
H
R
U
G
Fe process was observed for each diiron complex. Ligand-
6
8
6 8
centred reductive processes were observed at ꢀ1.09, ꢀ1.47
and ꢀ1.76 V for 14[PF ] , and at ꢀ1.07, ꢀ1.33 and ꢀ1.77 V
A
H
R
U
G
6
8
A
C
H
T
R
E
U
N
G
14
A
C
H
T
R
E
U
N
G
for 15[PF ] . All are quasi-reversible or irreversible, and the
A
H
R
U
G
6
8
6 8
2
+
ꢀ
ment [Mꢀ2PF ] . Loss of further PF led to a series of
peaks for the most negative processes in the cyclic voltam-
mograms were poorly resolved.
6
6
3
+
4+
peaks at m/z=813 ([Mꢀ3PF ] ), 573 ([Mꢀ4PF ] ), 430
6
6
5
+
6+
8+
(
[Mꢀ5PF ] , the base peak) and 334 ([Mꢀ6PF ] ). In the
Attempts to prepare 16 in a two-step process involving
6
6
3
+
2+
ES spectrum of 15
A
C
H
T
R
E
U
N
G
[PF ] , peaks at m/z=822 ([Mꢀ3PF ]
)
double N-alkylation of 2 with two equivalents of 10 fol-
6
8
6
4
+
and 580 ([Mꢀ4PF ] ) were observed in addition to a rela-
lowed by ring closure by treatment with a second equivalent
6
2
+
2+
tively intense peak at m/z=338 ([Fe
A
H
R
U
G
of 2 were unsuccessful. Although our efforts to prepare
2
2
+
2+
peak at m/z=407 and an intense peak at m/z=959 were as-
14 by reaction of 2 with an equimolar amount of 9 had
failed, this strategy proved to be the most efficient for the
formation of the related ruthenium(ii) macrocyclic complex
2
+
+
signed to 13 and [13+PF ] , respectively.
6
1
The solution H NMR spectra of 14
A
H
R
U
G
A
H
R
U
G
6
8
8
+
confirmed the formation of a symmetrical products. All
proton signals were fully assigned by standard techniques.
16 (Scheme 3). Equimolar amounts of the dibromo deriva-
tive 10 and 2[PF ] were heated at reflux in CH CN (concen-
AHCTREUNG
6
2
3
6
A
ꢀ2
ꢀ3
The shift of signals assigned to protons H (from d=8.91to
tration ꢁ10 moldm ) and the reaction was monitored by
TLC. Two pink products in addition to the red starting ma-
terial were observed after several hours, and a third pink
3
B
7
.01ppm) and H
from 12[PF ] to 14
domains to iron(ii). Similar shifts were observed on forming
[PF ] . We have previously pointed to the fact that pro-
(from d=8.88 to 9.16 ppm) on going
A
C
H
T
R
E
U
N
G
ACHTREUNG
[PF ] confirmed coordination of the tpy
6
2
6 8
material (R =0.1) appeared after 24 h. Over the next 72 h,
F
15
A
C
H
T
R
E
U
N
G
the last product became the predominant component of the
reaction mixture, and only traces of the initial two pink
6
8
A
4
5A
tons H and H are diagnostic probes for metallamacrocy-
[21]
clic complex versus metallapolymer formation. On going
products remained. After workup, 16
29% yield. The highest mass peak in the MALDI-TOF
mass spectrum of 16[PF ] was observed at m/z=2701
A
H
E
G
2
+
8+
from ligand 12
{d (complex)} is +0.21ppm for H and +0.56 ppm
(ligand)ꢀd
for H (both in CD CN). These are consistent with the for-
to complex 14 , the shift difference
4A
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
A
C
H
T
R
E
U
N
G
ACHTREUNG
6
8
5A
+
([Mꢀ2PF ] ), and the base peak (m/z=722) arose from the
3
6
Chem. Eur. J. 2006, 12, 4600 – 4610
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4605

E. C. Constable et al.
Scheme 3. Strategy for the formation of [2+2] ruthenium-containing mac-
3
rocycle: i) 10, CH CN, reflux. The ring labelling is that used for NMR
spectroscopic assignments.
8
+
1
5
) of the formation of a cyclic rather than acyclic system.
The presence of a single set of signals for the outer rings of
the tpy ligands indicated that the {Ru(tpy) } units undergo
rotation on the NMR spectroscopic timescale. The electron-
ic absorption spectrum of a solution of 16[PF ] in acetoni-
AHCTREUNG
2
AHCTREUNG
6
8
trile was similar to those of the N-alkylated ruthenium(ii)
complexes described above. An MLCT absorption was ob-
served at 507 nm, and intense bands in the UV region were
!
assigned to ligand-centred p* p transitions. The complex
16[PF ] was electrochemically active. CV and DPV studies
A
H
R
U
G
6 8
revealed
+1.06 V, which is reminiscent of the mononuclear rutheni-
um(ii) N-alkylated complexes discussed earlier. Three
ligand-centred reduction processes were observed at
a single metal-centred oxidation process at
AHCTREUNG
AHCTREUNG
ꢀ
1.03 V (reversible reduction), ꢀ1.48 V (quasi-reversible re-
duction) and ꢀ1.65 V (irreversible reduction).
Conclusion
We have prepared and characterised a series of N-alkylated
2
+
2+
derivatives of [Ru
A
H
R
U
G
(2 ), which includes both
2
model and functionalised complexes. The results have al-
lowed a comparison with analogous iron(ii) species, and il-
2
+
lustrate that the [M(pytpy) ] (M=Fe, Ru) complex has
A
H
R
U
G
2
the potential to be used as a building block for the forma-
tion of metallamacrocyclic complexes through N-alkylation
at the pendant pyridine rings. However, it has been shown
that a single synthetic approach cannot be used to form
both iron(ii) and ruthenium(ii) [2+2] metallamacrocycles.
8
+
8+
Figure 2. Space-filling models of 14 (top) and 15 (bottom) illustrating
the difference in the shape of the macrocyclic cavity which allows the
{
Fe
A
C
H
T
R
E
U
N
G
(tpy)
2
} units to approach more closely.
+
1
13
2+
fragment [Ru
A
C
H
T
R
E
U
N
G
(pytpy) ] . The solution H and C NMR
Whereas treatment of 2 with the dibromo derivative 10
2
8
+
spectra of the complex were fully assigned by using COSY,
HMQC and HMBC techniques, and confirmed the forma-
tion of a symmetrical species. The appearance of the signals
assigned to protons H and H at d=7.54 and 6.63 ppm,
respectively, was diagnostic (as discussed above for 14 and
leads to the formation of 16 in moderate yield, related
iron(ii) macrocycles could not be accessed by this route. A
two-step route involving the initial formation of ditopic li-
4
A
5A
2+
2+
gands 12 and 13 followed by treatment with iron(ii) was
8
+
found to be the most efficient means of generating macrocy-
4606
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ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 4600 – 4610

Metallamacrocycles
FULL PAPER
8
+
8+
cles 14 and 15 . In each dinuclear complex, electrochemi-
cal studies provide no evidence for electronic communica-
tion between the metal centres.
alkylating agent, and a red solid precipitated. This was filtered through
Celite and washed with methanol (5 cm ), and then water (20 cm ). The
solid was dried in air, and then removed from the Celite by dissolution in
3
3
CH
3
CN. After removal of solvent, 3
A
H
R
U
G
6 4
[PF ] was collected; a small amount
1
of residual benzyl bromide (shown by H NMR spectroscopy) was re-
3
2
moved by washing with Et O (3”5 cm ) and decanting the supernatant
+
solution. Yield 24 mg, 68%; ES-MS: m/z: 1339 [MꢀPF
6
] , 597
CN): d=9.14
s, 4H; H ), 9.09 (d(AB), J=7.0 Hz, 4H; H ), 8.77 (d(AB), J=7.0 Hz,
Experimental Section
2+
2+
1
[
(
Mꢀ2PF
6
]
, 362 [Ru
A
H
R
N
(pytpy)
2
]
;
H NMR (500 MHz, CD
3
3
B
2C
3
C
3A
General methods: Infrared spectra were recorded on a Mattson Genesis
Fourier transform spectrophotometer with samples in compressed KBr
discs or on a FTIR-8400S spectrophotometer with samples as solids using
4H; H ), 8.70 (ddd, J=8.3, 1.5, 0.8, 4H; H ), 8.00 (dt, J=7.8, 1.5 Hz,
4H; H ), 7.58 (m, 10H; H ), 7.43 (ddd, J=5.5, 1.5, 0.5 Hz, 4H; H ),
4
A
D
6A
5
A
7.23 (ddd, J=7.5, 5.5, 1.5 Hz, 4H;
2
H ), 5.91ppm (s, 4H; CH );
1
13
13
2A
2B
4B/4C
a Golden Gate ATR accessory. H and C NMR spectra were recorded
on Bruker AM250, DRX500 or DRX600 MHz spectrometers; the num-
bering scheme adopted for the ligands is shown in the structure diagrams,
and chemical shifts are referenced with respect to TMS d=0 ppm. UV/
Vis measurements were recorded on a Varian Cary 5000 UV/Vis/NIR
spectrophotometer in acetonitrile. Electrospray mass spectra (ESMS)
were recorded on a Finnigan MAT LCQ ESI/MS instrument. MALDI-
TOF mass spectra were recorded on a PerSeptive Biosystems Voyager
DEPRO Biospectrometry Workstation. Elemental analyses were carried
out in the Department of Chemistry, University of Basel, at CMAS Mi-
croanalytical Services, Melbourne, or at the Campbell Microanalytical
Laboratory, University of Otago. Electrochemical measurements were
performed with an Eco Chemie Autolab PGSTAT 20 system using glassy
C NMR (125 MHz, CD
3
CN): d=158.4 (C ), 157.0 (C ), 154.2 (C
),
6
A
2C
4C/4B
4A
1D
153.7 (C ), 146.4 (C ), 142.1 (C
), 139.7 (C ), 133.9 (C ), 131.2
4
D
2D/3D
3D/2D
5A
3C
3A
(C ), 130.7 (C
), 130.4 (C
), 129.1 (C ), 127.8 (C ), 126.1 (C ),
3
B
3
123.4 (C ), 65.6 ppm (CCH2); UV/Vis (CH
3
CN): lmax (e)=241(48.2” 10 ),
3
3
3
277 (74.1”10 ), 312 (31.5”10 ), 341(34.3 ”0 1
), 511 nm (35.9”
3
3
ꢀ1
ꢀ1
10 dm mol cm ); IR (solid): n˜ =3507 (w), 3399 (w), 3072 (w), 1664 (s),
1636 (s), 1524 (m), 1457 (m), 1423 (s), 1410 (m), 1355 (m), 1292 (m),
1249 (w), 1164 (m), 1091 (w), 1029 (m), 817 (vs), 793 (vs), 787 (vs), 740
ꢀ
1
(vs),
732 cm (s);
elemental
analysis
calcd
(%)
for
C
54
H
42
F
24
N
8
P
4
+
Ru·CH CN: C 44.1, H 3.0, N 8.3; found: C 44.0, H 2.9, 8.3;
3
E8 (vs. Fc/Fc ): +1.01, ꢀ0.98, ꢀ1.24, ꢀ1.52, ꢀ1.89 V (quasi-reversible re-
ductions).
Complex 4
A
H
R
U
G
6
]
4
: Complex 2
A
H
R
N
[PF
6
]
2
(20 mg, 0.020 mmol) and 2-bromo-
CN
20 cm ), and the solution was heated to reflux. After 24 h, heating was
carbon (except for 5
num auxiliary electrodes with a silver wire as quasi-reference; the work-
ing electrode was polished with aluminium oxide powder (0.3 microme-
A
C
H
T
R
E
U
N
G
[PF
6
]
4
A
H
R
U
G
6 4
) or platinum (for 5[PF ] ) working and plati-
A
H
R
U
G
3
3
(
3
stopped and a red precipitate was observed. Water (1cm ) was added
ter) before use; purified CH
3
CN (Fluka) was used as solvent and 0.1m
and the precipitate dissolved. The solution was concentrated in volume
3
[
nBu N][BF ] as supporting electrolyte. Potentials are quoted versus the
4
A
C
H
T
R
E
U
N
G
4
to 5 cm , and saturated aqueous NH
4
PF
6
was added to precipitate the
+
3
ferrocene/ferrocenium couple (Fc/Fc =0.0 V), and all potentials were
referenced to internal ferrocene added at the end of each experiment.
The compounds pytpy,
methylphenyl)-2,2’:6’,2’’-terpyridine were prepared by literature meth-
3
product. However, the residue formed an oil. CHCl (5 cm ) was added
in an attempt to remove excess alkylating agent, but no solid product
could be obtained from the biphasic mixture. The chloroform, excess
[
29]
2+
[29]
[54]
[55,56]
[Fe
A
H
R
U
G
2
57]
]
salts,
9,
10
and 4’-(4-
[
CH
3
CN and some water were removed by evaporation, causing the oil to
ods. All solvents were freshly distilled and reactions were carried out
form a dark pink solid. This was filtered through Celite and washed with
under N
Complexes 2
but with a heating time of 1h instead of 3 h. Reaction scale: RuCl
2
.
3
3
water (50 cm ) and CHCl
naphthalene. The solid was dried in air, and then removed from the
Celite by dissolution in CH CN. Solvent was removed, and the crude
product was purified by column chromatography (silica, CH CN/saturat-
ed aqueous KNO /water 7:1:0.5). The major pink fraction was collected,
evaporated and reprecipitated with NH
3
(30 cm ) to remove excess 2-bromomethyl-
[
30]
A
C
H
T
R
E
U
N
G
[PF
6
]
2
and 8
A
H
R
U
G
6
]
4
: The literature method was followed
·3H
19 mg, 0.079 mmol) and pytpy (49 mg, 0.16 mmol) in ethane-1,2-diol
3
2
O
3
(
(
3
3
10 cm ). Column chromatographic workup (silica, CH
/water 7:1:0.5) gave two fractions. The major red fraction
was collected and volume of solvent was reduced; 2[PF (54 mg, 68%)
was precipitated by addition of saturated methanolic solution of NH PF
Spectroscopic data were identical with those reported. A pink fraction
with lower R value than the major product was also collected and was
identified as [8]
3
CN/saturated
3
aqueous KNO
3
4
PF
6
solution to afford [4]
A
C
H
T
R
E
U
N
G
[PF
6
]
4
.
+
+
A
H
R
U
G
6
]
2
Yield 22 mg, 71%; ES-MS: m/z: 1439 [MꢀPF
6
] , 1294 [Mꢀ2PF
6
] , 1152
+
+
+
.
[Mꢀ
[Ru
(d(AB), J=6.9 Hz, 4H; H ), 8.83 (d(AB), J=6.9 Hz, 4H; H ), 8.72 (d,
A
H
R
U
G
2
2+
)ꢀ2PF
6
] , 867 [Ru
A
H
R
U
G
2
A
T
E
N
(PF
6
)] , 722 [Ru
A
H
R
U
G
2
] , 362
4
6
[
30]
1
3B
A
H
R
U
G
2 3
(pytpy) ] ; H NMR (500 MHz, CD CN): d=9.19 (s, 4H; H ), 9.18
2
C
3C
f
+
3A
1D
4D
A
C
H
T
R
E
U
N
G
[PF
6
]
4
(9 mg, 8%). FAB-MS: m/z: 1247 [MꢀPF
6
] , 1102
J=8.0 Hz, 4H; H ), 8.17 (s, 2H; H ), 8.07 (d, J=8.5, 2H; H ), 8.01
+
1
3B
5D,8D
4A
[
Mꢀ2PF
6
] ; H NMR (500 MHz, CD
3
CN): d=9.15 (s, 4H; H ), 9.03
(m, 4H; H
), 7.99 (dt, J=7.9, 1.3 Hz, 4H; H ), 7.66 (m, 6H;
2
C
3C
3D,6D,7D
6A
(
d(AB), J=7.0 Hz, 4H; H ), 8.76 (d(AB), J=6.5 Hz, 4H; H ), 8.69 (d,
H
), 7.43 (dd, J=5.7, 1.3 Hz, 4H; H ), 7.22 (ddd, J=7.4, 5.6,
3
A
4A
5A
13
J=8.0 Hz, 4H; H ), 8.01(dt, J=8.0, 1.5 Hz, 4H; H ), 7.44 (d, J=5.6,
.4, 0.7 Hz, 4H; H ), 7.24 (ddd, J=7.5, 5.7, 1.3 Hz, 4H; H ), 4.77 (t, J=
.0 Hz, 4H; CH ), 4.10 (brt, 4H; OCH ), 3.60 ppm (brs, 2H; OH);
2 3
1.2 Hz, 4H; H ), 6.07 ppm (s, 4H; CH ); C NMR (125 MHz, CD CN):
6
A
5A
2A
2B
4B/4C
6A
2C
1
d=158.3 (C ), 156.8 (C ), 154.0 (C
), 153.6 (C ), 146.5 (C ), 141.9
4
C/4B
4A
4aD/8aD
8aD/4aD
2D
5
2
2
(C
(C
(C
), 139.5 (C ), 134.5 (C
), 130.4 (C
), 128.2 (C
), 134.2 (C
), 128.9 (C ), 128.8 (C
), 131.2 (C ), 130.5
1
3
2A
2B
4B/4C
1D/4D
4D/1D
5D/8D
5A
8D/5D
C NMR (125 MHz, CD
3
CN): d=158.3 (C ), 156.8 (C ), 153.7 (C
),
), 129.1 (C
), 128.5
6
A
2C
4C/4B
4A
5A
6D/7D
7D/6D
3C
3D
3A
3B
1
53.6 (C ), 146.8 (C ), 142.1 (C
), 139.5 (C ), 128.9 (C ), 127.0
), 127.6 (C ), 126.7 (C ), 126.0 (C ), 123.3 (C ),
3
C
3A
3B
OCH
3
(
(
(
C
CH
), 125.9 (C ), 123.3 (C ), 64.7 (COCH CH2), 61.2 ppm (C
CN): lmax (e)=246 (40.9”10 ), 274 (90.3”10 ), 310 (38.2”10 ), 338
50.2”10 ), 508 nm (48.3”10 dm mol cm ); IR (solid): n˜ =3579 (w),
2
); UV/Vis
3
65.5 ppm (CCH2); UV/Vis (CH CN): lmax (e)=224 (114.5”10 ), 277 (57.7”
10 ), 341(23.3” 10 ), 513 nm (23.0”10 dm mol cm ); IR (solid): n˜ =
2
3
3
3
3
3
3
3
ꢀ1
ꢀ1
3
3
3
3
ꢀ1
ꢀ1
3400 (w), 3063 (w), 1668 (w), 1636 (s), 1603 (m), 1525 (w), 1422 (m),
3
1
084 (w), 1644 (s), 1605 (m), 1535 (m), 1467 (m), 1424 (s), 1398 (m),
1338 (s), 1331 (s), 1293 (m), 1248 (m), 1160 (m), 1091 (w), 1029 (m), 823
ꢀ
1
ꢀ1
355 (m), 1246 (w), 1174 (w), 1025 (m), 780 (vs), 751 (vs), 742 cm (s);
Ru·CH CN·H O: C
8.1, H 3.0, N 8.7; found: C 38.2, H 3.6, 8.6; E8 (vs. Fc/Fc )=+1.02,
(vs), 786 (vs), 754 cm
Ru·3CH
(vs), elemental analysis calcd (%) for
O: C 46.4, H 3.5, N 8.8; found: C 46.4, H
elemental analysis calcd (%) for C44
3
H
38
F
24
N
8
O
2
P
4
3
2
C
62
H
46
F
24
N
8
P
4
3
CN·3H
2
+
+
3.2, N 9.2; E8 (vs. Fc/Fc ): +1.01, ꢀ1.21, ꢀ1.47 V (quasi-reversible re-
ꢀ
0.89 (reversible reduction), ꢀ1.48 (quasi-reversible reduction), ꢀ1.96 V
ductions).
(
irreversible reduction).
Complex 5
A
H
R
U
G
6
]
4
: Complex 2
A
H
E
N
[PF
6
]
2
(21mg, 0.020 mmol) and 1,4-bis(bro-
CN
Complex 3
CH CN (25 cm ) and benzyl bromide (1.0 cm , 8.4 mmol) was added. The
red solution was heated under reflux for 2 h, after which TLC analysis
silica, CH CN/saturated aqueous KNO /water 7:1:0.5) revealed the dis-
A
C
H
T
R
E
U
N
G
[PF
6
]
4
: Complex 2
A
T
E
N
[PF
6
]
2
(21mg, 0.020 mmol) was dissolved in
momethyl)benzene (16 mg, 0.061 mmol) were dissolved in CH
3
3
3
3
3
(25 cm ) and the mixture heated at reflux for 72 h. The solution was then
3
concentrated in vacuo to ꢁ5 cm , and saturated aqueous solution of
(
3
3
4 6
NH PF was added to precipitate the crude product. The solid was fil-
3
appearance of all starting material and formation of a single pink prod-
uct. After evaporating the solvent, a saturated methanolic solution
tered through Celite and washed with water (20 cm ), and CHCl
3
3
(20 cm ) to remove excess 1,4-bis(bromomethyl)benzene. Purification of
3
(
5 cm ) of NH
4
PF
6
was added to the mixture of crude product and excess
the product by column chromatography (silica, CH
3
CN/saturated aque-
Chem. Eur. J. 2006, 12, 4600 – 4610
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
4607

E. C. Constable et al.
3
ous KNO
PF as a dark pink solid (12 mg, 35%). Crystalline material suitable
for microanalysis was obtained by diffusion of Et O vapour into a solu-
tion of 5[PF in CH CN. MALDI-TOF: m/z: 867 [Ru
(pytpy)
3
/water 7:1:0.5) and precipitation with aqueous NH
4
PF
6
afforded
itate (as the bromide salt). The solution was reduced in volume to 5 cm ,
5
6
]
4
and a saturated methanolic solution of NH PF was added to precipitate
the product as the hexafluorophosphate salt. After filtration through
Celite, the pink solid was washed with a small amount of cold CH OH,
followed by water to remove excess NH PF . The Celite was washed with
CH CN to remove the product, and solvent was removed. Complex 7-
6 4
[PF ] was isolated as a pink powder (29 mg, 72%). A small amount of
solid K CO was added to the NMR tube which was left standing for sev-
4
6
2
+
A
C
H
T
R
E
U
N
G
6
]
4
3
A
H
R
U
G
2
A
T
E
N
(PF
6
)] ,
3
+
2+
1
7
9
7
4
20 [Ru
A
C
H
T
R
E
U
N
G
2
3
] , 362 [Ru
A
H
R
U
G
2
]
3
4
6
B
2C
3
3
C
3A
.0 Hz, 4H; H ), 8.70 (d, J=8.0 Hz, 4H; H ), 8.00 (dt, J=8.0, 1.4 Hz,
A
H
R
N
4
A
D
6A
H; H ), 7.60 (m, 8H; H ), 7.43 (dd, J=5.3, 0.8 Hz, 4H; H ), 7.22
2 3
5
A
+
(
ddd, J=7.7, 5.7, 1.1 Hz, 4H; H ), 5.89 (s, 4H; NCH
CH Br); UV/Vis (CH CN): lmax =238, 274, 309, 337, 512; elemental anal-
ysis calcd (%) for C56 Ru·CH CN·H O: C 39.9, H 2.9, N 7.2;
2
), 4.65 ppm (s, 4H;
eral hours. ES-MS: m/z: 1334 [MꢀCH C H tpyꢀ2PF ] , 867 [Ru-
2
6
4
6
+
+
+
2
3
A
H
R
U
G
A
T
E
N
(PF
)] , 722 [Ru
A
T
U
G
] , 632 [pytpyCH
2
C
H
tpy] , 362 [Ru-
2
6
1
2
6
4
H
44Br
2
F
24
N
8
P
4
3
+
2
2+
3B
A
H
R
U
G
2
]
3
; H NMR (500 MHz, CD CN): d=9.18 (s, 4H; H ), 9.17 (d,
J=6.5 Hz, 4H; H ), 8.80 (d, J=7.0 Hz, 4H; H ), 8.79 (s, 4H; H ), 8.74
m, 4H; H ), 8.72 (d, J=8.0 Hz, 4H; H ), 8.70 (d, J=8.0 Hz, 4H; H ),
8.12 (d, J=8.5 Hz, 4H; H ), 8.04 (dt, J=7.8, 1.8 Hz, 4H; H ), 8.00 (dt,
J=8.0, 1.5 Hz, 4H; H ), 7.81(d, J=8.5 Hz, 4H; H ), 7.52 (ddd, J=7.5,
5.0, 1.0 Hz, 4H; H ), 7.43 (d, J=5.5 Hz, 4H; H ), 7.22 (ddd, J=8.0, 5.5,
2 3
1.0 Hz, 4H; H ), 6.01ppm (s, 4H; C H ). C NMR (125 MHz, CD CN):
), 156.0 (C ), 154.1 (C ),
), 140.7 (C ), 139.5
(C ), 139.0 (C ), 134.9 (C ), 131.2 (C ), 129.3 (C ), 128.9 (C ), 127.7
(C ), 126.0 (C ), 125.6 (C ), 123.3 (C ), 122.4 (C ), 119.7 (C ),
max (e)=249 (104.1”10 ), 275
134.6”10 ), 511 nm (35.6”10 dm mol cm ); IR (solid): n˜ =3648 (w),
found: C 39.5, H 2.9, N 7.2; E8 (vs. Fc/Fc ): +1.01, ꢀ0.91, ꢀ1.61 V (irre-
2C
3C
3E
versible reductions).
6F
3F
3A
(
2
D
4F
Complex 6
modecane (0.50 cm , 2.2 mmol) were dissolved in CH
the mixture was heated at reflux for 24 h. Additional 1,10-dibromodecane
A
C
H
T
R
E
U
N
G
[PF
6
]
4
: Complex 2
A
H
R
U
G
6
]
2
(42 mg, 0.042 mmol) and 1,10-dibro-
3
3
4A
3D
3
CN (30 cm ) and
5
F
6A
3
5A
13
(
0.50 cm , 2.2 mmol) was then added and heating was continued for a fur-
2
B,2E
4E
4B/4C
2F
2A
ther 30 h. Solvent was then evaporated and the residue triturated with
d=158.2 (C
), 156.85 (C ), 156.8 (C
3
6A
6F
2C
4B/4C
1D
chloroform (5 cm ) to give a red precipitate. The solid was filtered
153.5 (C ), 150.0 (C ), 146.5 (C ), 141.9 (C
3
4A
4F
4D
3D
2D
5A
through Celite and was washed with chloroform (30 cm ) to remove
3
C
3A
5F
3B
3F
3E
excess 1,10-dibromodecane. Aqueous CH
3
CN (1:1) was used to wash the
crude product from the Celite, and the red solution was concentrated in
3
6
(
4.9 ppm (CH
2
); UV/Vis (CH
3
CN):
l
ꢀ1
3
volume to ꢁ5 cm . Addition of saturated aqueous NH
precipitation of the crude product. This was collected by filtration and
purified by column chromatography (silica, CH CN/saturated aqueous
KNO /water 7:1:0.5). The major red fraction was collected, and 6[PF
was precipitated from solution as a red solid on addition of saturated
4
PF
6
resulted in
3
3
3
ꢀ1
3
1
7
069 (w), 1637 (s), 1604 (w), 1583 (m), 1469 (m), 1422 (s), 1391 (m),
358 (m), 1292 (w), 1165 (m), 1090 (w), 825 (vs), 785 (vs), 751 (s),
3
A
H
R
U
G
6
]
4
ꢀ1
3
40 cm (s); elemental analysis calcd (%) for C84
H N14RuP F24·9H O:
60 4 2
+
C 47.9, H 3.7, N 9.3; found: C 47.7, H 3.5, N 9.3; E8 (vs. Fc/Fc ): +1.01,
0.99 (quasi-reversible reduction), ꢀ1.72 V (irreversible reduction).
Complex 11[PF : [Fe(pytpy) [PF (114 mg, 0.118 mmol) was heated
to reflux in CH CN (15 cm ). A solution of 9 (20 mg, 0.059 mmol) was
added over 6 h and heating was continued for another 72 h. A saturated
aqueous solution of NH PF was added to the blue reaction mixture and
the precipitate that formed was collected by filtration. Column chroma-
tography (silica, CH CN/saturated aqueous KNO /water 7:1:0.5) was
+
aqueous NH
Mꢀ2PF
4
PF
6
. Yield 54 mg, 74%; ES-MS: m/z: 1597 [MꢀPF
] , 529 [Br(CH 10pytpy] , 362 [Ru(pytpy)
3
500 MHz, CD CN): d=9.19 (s, 4H; H ), 9.04 (d(AB), J=7.0 Hz, 4H;
6
1
] , 1451
ꢀ
+
+
2+
[
(
H
8
(
(
1
2
(
1
6
A
C
H
T
R
E
U
N
G
2
)
A
H
R
U
G
2
] ;
H NMR
A
H
R
U
G
6
]
6
A
H
E
N
2
]
A
H
R
U
G
6 2
]
3
B
3
2
C
3C
3A
3
), 8.78 (d(AB), J=6.8 Hz, 4H; H ), 8.72 (d, J=8.0 Hz, 4H; H ),
4
A
6A
.01(dt, 8.0, 1. 3 Hz, 4H; H
ddd, J=7.5, 5.7, 1.1 Hz, 4H; H ), 4.68 (t, J=7.5 Hz, 4H; NCH
t, J=6.8 Hz, 4H; CH Br), 2.11 (quintet, J=7.2 Hz, 4H; NCH
.84 (quintet, J=7.0 Hz, 4H; CH CH Br), 1.3–1.5 ppm (overlapping m,
CN): d=158.3 (C ), 156.9 (C ), 153.6
), 7.45 (dd, J=5.4, 0.8 Hz, 4H; H ), 7.23
5
A
4
6
2
), 3.48
CH ),
2
2
2
3
3
2
2
1
3
2A
2B
used to separate the dark blue product, which was eluted as the third
fraction. The volume of solvent in the fraction was reduced to half under
4H; CH
2
); C (125 MHz, CD
3
6
A
4C/4B
2C
4C/4B
4A
5A
C
), 153.4 (C
), 146.2 (C ), 141.9 (C
), 139.5 (C ), 128.9 (C ),
3
C
3A
3B
vacuum, and a solution of aqueous NH
11[PF , which was separated by filtration. This process was repeated
several times to ensure complete ion exchange. Complex 11
4 6
PF was added to precipitate
27.4 (C ), 126.0 (C ), 123.2 (C ), 62.7 (CNCH2), 35.4 (CCH Br), 33.5
2
A
H
R
U
G
A
T
E
N
6 6
]
(
2
3
C
CH2), 31.8 (CNCH CH2), 29.9 (CCH2), 29.5 (CCH2), 29.3 (CCH2), 28.7 (CCH2),
2
3
A
C
H
T
R
E
U
N
G
[PF ] was
6.6 (CCH2), 22.4 (CCH CH Br); UV/Vis (CH
05 (48.0”10 ), 340 (39.7”10 ), 509 nm (31.9”10 dm mol cm ); IR
3
CN): lmax (e)=276 (96.9”10 ),
6
6
6
+
2
2
3
3
3
3
ꢀ1
ꢀ1
isolated as a blue solid (33 mg, 23%). ES MS: m/z: 255 [Mꢀ6PF ] , 456
6
4
+
3+
1
[
4
Mꢀ4PF
6
]
, 656 [Mꢀ3PF
6
3B
]
; H NMR (250 MHz, CD
3
CN): d=9.32 (s,
(
solid): n˜ =3075 (w), 2925 (m), 2853 (m), 1663 (m), 1640 (s), 1604 (m),
3
F
2C
H; H ), 9.26 (s, 4H; H ), 9.20 (d, J=6.8 Hz, 4H; H ), 9.03 (d, J=
1
1
527 (m), 1484 (w), 1467 (w), 1423 (s), 1360 (m), 1293 (w), 1248 (w),
3
G
3C
3E,3A
ꢀ
1
6.4 Hz, 4H; H ), 8.91(d, J=6.8 Hz, 4H; H ), 8.65 (m, 8H; H
), 8.24
175 (m), 1030 (m), 820 (vs), 788 cm (vs); elemental analysis calcd (%)
Br RuP O C 40.5, H 4.0, N 6.3; found: C 40.5, H 4.0,
2
G
4E,4A
(
d, J=5.9 Hz, 4H; H ), 7.94 (m, 8H; H
), 7.93 (d(AB), J=8.3 Hz,
for C60
H
68
N
8
2
4 2
F24·2H
+
2
D/3D
3D/2D
6E,6A
4H; H
7
), 7.77 (d(AB), J=8.3 Hz, 4H; H
), 7.17 (m, 8H; H
),
N 6.5; E (vs. Fc/Fc ): +0.99, ꢀ1.02, ꢀ1.58, ꢀ1.90 V (irreversible reduc-
5
E,5A
+
.12 (m, 8H; H
), 6.00 ppm (s, 4H; CH ); E8 (vs. Fc/Fc ): +1.04,
2
tions, poorly resolved).
+
0.79 V.
4
’-(4-Bromomethylphenyl)-2,2’:6’,2’’-terpyridine: This was prepared by a
[
57]
route modified from that reported by Calzaferri. 4’-(4-Methylphenyl)-
Complound 12
(70 mg, 0.21mmol) in CH
then allowed to cool to room temperature. The white precipitate that
formed was collected by filtration, was washed with CH Cl and then was
redissolved in CH OH. A saturated aqueous solution of NH PF in
CH OH (made slightly basic by addition of ten drops N-ethylmorpho-
line) was added, and the resulting precipitate was collected by filtration.
After being washed with CH Cl , the product was dried under vacuum.
Compound 12[PF ] was isolated as a white solid (140 mg, 62%). M.p.
195–1968C; MALDI-TOF MS: m/z: 947 [MꢀPF ] , 801[ Mꢀ2PF ] ;
A
H
R
U
G
6 2
[PF ] : A mixture of pytpy (132 mg, 0.43 mmol) and 9
3
2
2
(
,2’:6’,2’’-terpyridine (0.65 g, 2.0 mmol) and N-bromosuccinimide (0.37 g,
.1mmol) were dissolved in benzene (60 cm ). Dibenzoyl peroxide
ꢁ20 mg) was added, and the reaction mixture heated under reflux for
3
CN (10 cm ) was heated at reflux for 4 h and
3
2
2
4
2 h. After cooling to room temperature, the suspension was filtered and
3
4
6
3
the solution was washed with water (2”20 cm ), dried over Na
2
SO
4
and
3
the solvent removed under reduced pressure. Recrystallisation of the
brown solid from EtOH/acetone (2:1) gave 4’-(4-Bromomethylphenyl)-
2
2
2
,2’:6’,2’’-terpyridine as white needles, which were collected by filtration
ACHTREUNG
6
2
+
+
and washed with a small amount of cold 95% EtOH. Yield 377 mg,
6
6
[
57–59]
1
6A
4
7%; spectroscopic data were identical to those in the literature.
Complex 7[PF : Complex 2[PF (21mg, 0.020 mmol) and 4 ’-(4-bromo-
methylphenyl)-2,2’:6’,2’’-terpyridine (17 mg, 0.42 mmol) were dissolved in
3
H NMR (250 MHz, CD CN): d=8.91(d, J=6.8 Hz, 4H; H ), 8.88 (s,
3
B
3C,2C/3A
2C/3 A
A
C
H
T
R
E
U
N
G
6
]
4
A
H
R
U
G
6
]
2
4H; H ), 8.73 (m, 8H; H
), 8.50 (d, J=6.8 Hz, 4H; H
), 8.01
), 7.59 (d,
4
A
2D/3D
(ddd, J=7.8, 2.0 Hz, 4H; H ), 7.80 (d, J=8.8 Hz, 4H; H
J=8.3 Hz, 4H; H
3
2D/3D
5A
CH
3
CN (20 cm ), and the red solution was heated under reflux for 48 h,
), 7.55 (m, 4H; H ), 5.83 ppm (s, 4H; CH
2
); UV/
(73.1”
3
followed by addition of more 4’-(4-bromomethylphenyl)-2,2’:6’,2’’-terpyri-
dine (8 mg, 0.2 mmol); the extent of reaction was monitored by TLC
Vis
(CH
3
ꢀ1
CN):
l
max
(e)=336
(7.6”10 ),
272 nm
3
3
ꢀ1
10 dm mol cm ); IR (KBr): n˜ =3125 (w), 3103 (w), 3058 (w), 1639
analysis (silica, CH
heating for 18 h allowed the reaction to proceed to completion. The for-
mation of a fine pink precipitate was observed. The mixture was cooled
3
CN/saturated aqueous KNO
3
/water 7:1:0.5). Further
(m), 1606 (w), 1585 (m), 1567 (w), 1549 (w), 1519 (w), 1471 (w), 1395
ꢀ
ꢀ1
(m), 1155 (w), 840 (s; PF
6
), 791(m), 781(m), 740 (w), 558 cm
(m;
ꢀ
PF
6
); elemental analysis calcd (%) for C54
H
40
F
12
N
8
P
2
·6H O: C 54.10, H
2
3
to room temperature, and water (2 cm ) was added to dissolve the precip-
4.37, N 9.35; found: C 54.31, H 4.32, N 9.24%.
4608
www.chemeurj.org
ꢀ 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2006, 12, 4600 – 4610

Metallamacrocycles
FULL PAPER
3
Compound 13
60 mg, 0.17 mmol) in CH
Workup and purification was as for 12
A
C
H
T
R
E
U
N
G
[PF
6
]
2
: A mixture of pytpy (116 mg, 0.37 mmol) and 10
30 cm ). Solid NH
4
PF
6
(ꢁ200 mg) was added, and the suspension was
3
(
3
CN (10 cm ) was heated under reflux for 6 h.
[PF ; compound [13][PF was
stirred until all of the silica was decolorised (30 min). The silica was re-
moved by filtration, and the CH
A
H
R
U
G
6
]
2
A
H
R
U
6
]
2
3
CN removed in vacuo leaving a pink
isolated as a white solid (103 mg, 55%). MALDI-TOF MS: m/z: 959
precipitate. After filtering the suspension through Celite, the product was
+
+
1
3
[
8
(
H
MꢀPF
6
] , 502 [Mꢀpytpyꢀ2PF
6
] ; H NMR (250 MHz, CD
3
CN): d=
washed with water (50 cm ) and then dissolved in CH
3
CN. Solvent evapo-
2
C
3B
6A
.84 (d, J=7.0 Hz, 4H; H ), 8.79 (s, 4H; H ), 8.67 (m, 4H; H ), 8.66
ration yielded 16[PF as a dark pink solid (10 mg, 29%). MALDI TOF:
A
H
R
U
G
6 8
]
3
A
3C
+
m, 4H; H ), 8.42 (d, J=7.0 Hz, 4H; H ), 7.96 (dt, J=7.8, 1.5 Hz, 4H;
m/z: 2701[ Mꢀ2PF
6
] , 1482 [(tpy)Ru(pytpyCH
2
C
6
H
4
CH
2 6 4
C H -
4
A
5A
2D/3D
+
+
1
), 7.44 (m, 4H; H ), 7.40 (d(AB), J=8.5 Hz, 4H; H
), 7.36
), 4.04 ppm (s, 2H;
); IR (KBr): n˜ =3126 (w), 3103 (w), 3060 (w), 3028 (w), 1639 (m),
A
H
R
U
G
2
pytpy)Ru
A
H
R
U
G
A
H
R
U
G
2
] ; H NMR (500 MHz, CD CN):
3
3
D/2D
3B
2C
(
d(AB), J=8.5 Hz, 4H; H
), 5.72 (s, 4H; NCH
2
d=9.12 (s, 8H; H ), 9.00 (d, J=7.0 Hz, 8H; H ), 8.75 (d, J=7.0 Hz,
8H; H ), 8.55 (td, J=8.0, 1.5 Hz, 8H; H ), 7.55 (s, 16H; H ), 7.54 (dt,
J=8.0, 1.5 Hz, 8H; H ), 7.28 (ddd, J=5.5, 1.5, 0.5 Hz, 8H; H ), 6.63
2
(ddd, J=7.5, 5.5, 1.5 Hz, 8H; H ), 5.85 (s, 8H; NCH ), 4.13 ppm (s, 4H;
3
C
3A
D
CH
2
4
A
6A
1
1
606 (w), 1585 (m), 1568 (w), 1549 (m), 1516 (w), 1471 (w), 1395 (m),
ꢀ
ꢀ1
ꢀ
5A
155 (w), 841 (s; PF
[PF
.069 mmol) in CH
.068 mmol) in CH
OH and CH
room temperature. The volume of solvent was then reduced to 500 cm
under vacuum, and a saturated aqueous solution of NH PF was added.
A blue precipitate formed and was collected by filtration. This was dis-
solved in CH CN and a saturated aqueous solution of KNO was added;
6
), 791(m), 781(m), 740 (w), 558 cm
Nitrogen-purged solutions of 13[PF
·6H
(m; PF
6
).
1
3
2A
2B
2 3
CH ); C NMR (125 MHz, CD CN): d=158.2 (C ), 156.5 (C ), 154.1
Complex 14
0
0
A
C
H
T
R
E
U
N
G
6
]
8
:
A
H
R
U
G
6
]
2
(75 mg,
(23 mg,
4
B/4C
6A
2C
1D
4C/4B
4A
3
(C
), 153.3 (C ), 146.1 (C ), 144.3 (C ), 142.1 (C
), 138.9 (C ),
3
CN (500 cm ) and Fe
A
H
R
U
G
4
)
2
2
O
4
D
2D/3D
3D/2D
5A
3C
3
131.4 (C ), 130.9 (C
), 130.7 (C
), 128.4 (C ), 127.5 (C ), 125.9
3
OH (500 cm ) were added simultaneously to a stirred
3
A
3B
3
(C ), 123.5 (C ), 64.9 (CNCH2), 41.9 ppm (CCH2); UV/Vis (CH
(e)=222 (107.4”10 ), 236 (95.0”10 ), 274 (127.9”10 ), 311 (62.5”10 ),
40 (62.5”10 ), 507 nm (57.2”10 cm ); IR (solid): n˜ =2966 (m), 2879
m), 1473 (s), 1399 (m), 1045 (w), 880 (m), 832 (vs), 793 (m), 740 cm
m); elemental analysis calcd (%) for C110 Ru ·5H O: C 42.87,
3
CN): lmax
mixture of CH
3
3
CN (1:1, 500 cm ) over a four day period at
3
3
3
3
3
3
3
ꢀ1
3
4
6
ꢀ
1
(
(
H
84
F
48
N
16
P
8
2
2
3
3
+
H 3.07, N 7.27; found C 42.87, H 3.26, N 7.14; E8 (vs. Fc/Fc ): +1.06,
1.03 (reversible reduction), ꢀ1.48(quasi-reversible reduction), ꢀ1.65 V
irreversible reduction).
X-ray crystal structure analysis of [3]
the precipitate formed was removed by filtration leaving an enriched sol-
ution of the desired product. The procedure was repeated until TLC
ꢀ
(
(
silica, CH
of a single product (R
of the product in CH
3
CN/saturated aqueous KNO
=0.32). Aqueous NH
CN and the precipitate that formed was collected
3
/H
2
O 7:2:2) showed the presence
A
H
R
U
G
6
]
4 3 2 3
·2(CH ) CO·0.3CH CN: De-
A
H
R
U
G
f
4
PF was added to a solution
6
termination of the cell parameters and collection of the reflection intensi-
ties were performed on an Enraf-Nonius Kappa CCD diffractometer
3
by fitration. This step was repeated several times to ensure that anion ex-
(
graphite monochromated MoKa radiation, l=0.71073 Š). Purple plate,
0.12”0.16”0.47 mm, monoclinic, space group P2 /n, a=8.9023(13) , b=
b=107.400(9)8, T=173 K, V=
(000)=3250.4.
change was complete. The final precipitate was dissolved in a mixture of
3
1
CH
3
CN and CH
3
OH (1:1, 50 cm ) and Et
2
O was added until a blue pre-
5
6
6.033(6),
c=14.1966(16) Š,
cipitate formed and a colourless supernatent liquid were obtained; this
step was repeated several times. Complex 14[PF was obtained as a
blue solid (69 mg, 35%). ES-MS: m/z: 1291 [Mꢀ2PF
Mꢀ3PF 573 [Mꢀ4PF 430 [Mꢀ5PF 334 [Mꢀ6PF
H NMR (250 MHz, CD
3
ꢀ3
ꢀ1
757.5(15) Š , Z=4, 1calcd =1.585 gcm , m=0.442 mm , F
AHCTREUNG
A
H
R
U
G
6 8
]
2
+
Number of reflections measured 55219 (unique 31808); 10733 observed
6
]
,
81
]
3
3
+
4+
5+
6+
reflections, I>3s(I), were used for the determination (1009 parameters);
[
6
]
,
6
]
,
6
]
,
6
;
[
60]
[61]
[62]
1
3B
direct methods, Denzo/Scalepack,
SIR92.
CRYSTALS
was used
3
CN): d=9.16 (s, 8H; H ), 9.14 (d, J=6.9 Hz,
2
C
3C
3A
for structure refinement. The refinement converged at R=0.2294 (all
data), 0.0854 [observed I>3s(I)], wR=0.2301(all data), 0.0965 [ob-
served I>3s(I)], min and max residual electron density 1.88 and
8
7
8
H; H ), 8.76 (d, J=6.6 Hz, 8H; H ), 8.50 (d, J=8.2 Hz, 8H; H ),
2
D/3D
4A
.83 (d, J=8.5 Hz, 8H; H
), 7.80 (m, 8H; H ), 7.70 (d, J=8.5 Hz,
3
D/2D
6A
5A
H; H
), 7.01(m, 8H; H ), 6.99 (m, 8H; H ), 5.97 ppm (s, 8H;
ꢀ
3
3
3
ꢀ1.45 eŠ ; gof=1.123. CCDC-294985 contains the supplementary crys-
tallographic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
CH
54.1”10 ), 384 (17.7”10 ), 599 nm (46.8”10 dm mol cm ); IR (KBr):
n˜ =1638 (s), 1608 (w), 1523 (w), 1425 (m), 1158 (w), 1091 (w), 838 (s;
2
); UV/Vis (CH CN): lmax (e)=294 (157.8”10 ), 286 (150.8”10 ), 330
3
3
3
3
3
ꢀ1
ꢀ1
(
ꢀ
ꢀ1
ꢀ
+
PF
+0.85, ꢀ1.09, ꢀ1.47, ꢀ1.76 V.
Complex 15[PF : The method of preparation was as for complex 14-
[PF starting with [13][PF (30 mg, 0.027 mmol) and Fe(BF ·6H
10 mg, 0.030 mmol). Complex 15
13 mg, 16%). ES-MS: m/z: 959 13+PF
6
), 788 (m), 755 (w), 593 (w), 558 cm (m; PF ); E8 (vs. Fc/Fc ):
6
Molecular modelling: Molecular mechanics calculations was carried out
at the MM+ level using HyperChem release 7.0 (Hypercube Inc., 2002)
in order to gain approximate structures of the iron(ii) macrocyclic com-
plexes.
ACHTREUNG
A
C
H
T
R
E
U
N
G
6 8
]
A
C
H
T
R
E
U
N
G
6
]
8
A
C
H
T
R
E
U
N
6
]
2
A
H
R
U
G
4
)
2
2
O
(
(
[
A
H
R
U
G
6
]
8
was collected as a blue powder
+
3+
6
] , 822 [Mꢀ3PF
6
] , 580
4
+
2+
2+
1
Mꢀ4PF
6
]
,
407 [13]
,
A
H
R
U
G
2
]
;
H NMR (600 MHz,
3
B
2C
3
CD CN): d=9.19 (s, 8H; H ), 9.03 (d, J=6.5 Hz, 8H; H ), 8.78 (d, J=
.0 Hz, 8H; H ), 8.44 (d, J=8.0 Hz„ 8H; H ), 7.57 (m, 16H; H
.44 (dt, J=7.5, 1.0 Hz, 8H; H ), 6.99 (d, J=5.0 Hz, 8H; H ), 6.52 (dt,
J=6.5, 1.0 Hz, 8H; H ), 5.90 (s, 8H; NCH
3
C
3A
2D,3D
7
7
),
Acknowledgements
4
A
6A
5
A
2
), 4.18 ppm (s, 4H; CH
2
);
We thank the Swiss National Science Foundation and the University of
Basel for financial support. Sebastien Reymann is thanked for recording
some of the ES mass spectra, and Jon Beves for recording some of the
NMR spectra.
3
3
UV/Vis (CH
3
CN): lmax (e)=278 (132.4”10 ), 286 (131.8”10 ), 332 (51.3”
3
3
3
3
ꢀ1
ꢀ1
1
1
0 ), 379 (17.5”10 ), 595 nm (44.1”10 dm mol cm ); IR (KBr): n˜ =
639 (s), 1424 (m), 841 (s; PF ), 790 (m), 559 cm (m; PF ). E8 (vs. Fc/
ꢀ
ꢀ1
ꢀ
6
6
+
Fc ): +0.86, ꢀ1.07, ꢀ1.33, ꢀ1.77 V.
Complex 16[PF Complex [PF
8.1mg, 0.023 mmol) were dissolved in CH
tion was heated under reflux. After several hours, TLC analysis (silica,
CH CN/saturated aqueous KNO /water 7:1:0.5) showed the presence of
two pink spots with higher R values than the starting material. After
4 h, a further pink product (low R =0.1) was detected. Over the next
2 h, the amount of this material increased at the expense of both 2[PF
pink fractions, until it became the dominant product.
The solution was cooled to ambient temperature and the solvent was
evaporated. Column chromatography (silica gel, CH CN/saturated aque-
ous KNO /water 7:1:0.5) was used to separate the components. The
A
C
H
T
R
E
U
N
G
6
]
8
:
2
A
H
R
U
6 2
] (23.2 mg, 0.023 mmol) and 10
3
(
3
CN (20 cm ) and the red solu-
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4610
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Chem. Eur. J. 2006, 12, 4600 – 4610