Tetratopic pyrimidine-hydrazone ligands modified with terminal hydroxymethyl and acryloyl arms and their Pb(ii), Zn(ii), Cu(ii) and Ag(i) complexes

Article abstract of DOI:10.1039/c3dt53559b

The first tetratopic pyrimidine-hydrazone (pym-hyz) molecular strands containing terminal hydroxymethyl (L1) and acryloyl (L2) functional groups have been synthesised. L1 was produced by step-wise imine condensation reactions, starting with 6-hydroxymethyl-2-pyridinecarboxaldehyde. L2 was then synthesised through the treatment of L1 with acryloyl chloride. NMR spectroscopy and X-ray crystallography showed that the ligands adopted a helical shape, comprised of 1 and 1/3 helical turns. Both L1 and L2 uncoiled upon reaction with an excess amount of Pb(ii), Zn(ii) and Cu(ii) ions, resulting in linear M ₄LA₈ complexes (where M = Pb(ii), Zn(ii), or Cu(ii); L = L1 or L2; and A = ClO₄^-, SO₃CF₃ ^- or BF₄^-). Horse-shoe shaped Pb ₂LA₄ complexes were also formed by reacting Pb(ii) ions with either L1 or L2 in a 2 : 1 metal to ligand ratio. The addition of Ag(i) ions to either L1 or L2 resulted in Ag₂L₂A₂ double helicates, which were stable in the presence of excess Ag(i). The Pb(ii), Zn(ii) and Ag(i) complexes were characterised by NMR spectroscopy, while UV-Vis spectroscopy was used to probe the Cu(ii) complexes. In addition, X-ray crystallography was used to analyse the linear Pb₄L1A₈, horse-shoe shaped Pb₂L1(ClO₄)₄, twisted Cu ₃L2(SO₃CF₃)₆, and double helicate Ag₂L1₂(SO₃CF₃)₂ complexes yielding the structures [Pb₄L1(ClO₄)₇(H ₂O)]ClO₄·4CH₃NO₂ (1), [Pb₄L1(SO₃CF₃)₈]₂· 6CH₃CN·H₂O (2), [Pb₂L1(ClO ₄)₂(CH₃CN)(H₂O)](ClO ₄)₂·2CH₃CN·C₄H ₁₀O·H₂O (3), [Cu₃L2(SO ₃CF₃)₃(CH₃CN)₂(H ₂O)](SO₃CF₃)₃·2CH ₃CN·H₂O (4) and [Ag₂L1 ₂](SO₃CF₃)₂·CH ₃CN·H₂O (5), respectively. the Partner Organisations 2014.

Full text of DOI:10.1039/c3dt53559b

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Tetratopic pyrimidine–hydrazone ligands modified
with terminal hydroxymethyl and acryloyl arms
and their Pb(II), Zn(II), Cu(II) and Ag(I) complexes†
Cite this: Dalton Trans., 2014, 43,
8205
Daniel J. Hutchinson, Lyall R. Hanton* and Stephen C. Moratti
The first tetratopic pyrimidine–hydrazone (pym–hyz) molecular strands containing terminal hydroxy-
methyl (L1) and acryloyl (L2) functional groups have been synthesised. L1 was produced by step-wise
imine condensation reactions, starting with 6-hydroxymethyl-2-pyridinecarboxaldehyde. L2 was then
synthesised through the treatment of L1 with acryloyl chloride. NMR spectroscopy and X-ray crystallo-
graphy showed that the ligands adopted a helical shape, comprised of 1 and 1/3 helical turns. Both L1 and L2
uncoiled upon reaction with an excess amount of Pb(II), Zn(II) and Cu(II) ions, resulting in linear M4LA8
−
complexes (where M = Pb(II), Zn(II), or Cu(II); L = L1 or L2; and A = ClO4−, SO3CF3 or BF4−). Horse-shoe
shaped Pb2LA4 complexes were also formed by reacting Pb(II) ions with either L1 or L2 in a 2 : 1 metal to
ligand ratio. The addition of Ag(I) ions to either L1 or L2 resulted in Ag2L2A2 double helicates, which were
stable in the presence of excess Ag(I). The Pb(II), Zn(II) and Ag(I) complexes were characterised by NMR
spectroscopy, while UV-Vis spectroscopy was used to probe the Cu(II) complexes. In addition, X-ray
crystallography was used to analyse the linear Pb4L1A8, horse-shoe shaped Pb2L1(ClO4)4, twisted Cu3L2-
(SO3CF3)6, and double helicate Ag2L12(SO3CF3)2 complexes yielding the structures [Pb4L1(ClO4)7(H2O)]-
ClO4·4CH3NO2 (1), [Pb4L1(SO3CF3)8]2·6CH3CN·H2O (2), [Pb2L1(ClO4)2(CH3CN)(H2O)](ClO4)2·2CH3CN·
C4H10O·H2O (3), [Cu3L2(SO3CF3)3(CH3CN)2(H2O)](SO3CF3)3·2CH3CN·H2O (4) and [Ag2L12](SO3CF3)2·
CH3CN·H2O (5), respectively.
Received 18th December 2013,
Accepted 28th February 2014
DOI: 10.1039/c3dt53559b
www.rsc.org/dalton
hyz linkages to their cisoid conformation.4,9 The strands there-
fore exhibit nanomechanical action, akin to a two-stroke linear
Introduction
The construction of molecular machines which mimic the motor, stimulated by the reversible binding of metal ions.4
motions demonstrated by nature’s vast array of nanoscale
While artificial molecular actuator systems, such as the
machinery continues to be one of the many challenges facing pym–hyz molecular strands, have been developed, their useful-
chemists.1 Biomolecules such as myosin2 have been a source ness in performing tasks on a macroscopic scale has yet to be
of inspiration, leading to the design of synthetic actuating realised.10 One strategy for harnessing molecular scale
molecules that exhibit reversible expansion and contraction motions for macroscopic tasks requires the assembly of mole-
motions in response to an external stimulus.3 To this end, cular actuators into larger integrated systems,11 such as
molecular strands of repeating pyrimidine–hydrazone (pym– polymer gel actuators. These gels are capable of significant
hyz) units have been studied due to their molecular actuating volume and shape changes upon the incidence of a wide range
behaviour.4 The strong preference of the pym–hyz linkage for a of external stimuli,12 and consequently have potential appli-
transoid conformation5 results in the folding of the molecular cations in the realms of soft robotics13 and microfluidics.14
strand into a helix,6–8 which is then uncoiled to form a linear
Our research is focused on creating a polymer gel actuator
strand upon the metal ion induced isomerisation of the pym– containing pym–hyz strands which would act as an artificial
muscle; expanding and contracting due to the coordination of
metal ion guest molecules in the solution phase to the pym–
hyz host molecules within the gel network. The incorporation
of pym–hyz strands into a gel first requires that functional
groups capable of undergoing polymerisation with a co-
monomer be appended to the strands. So far we have syn-
thesised and studied ditopic pym–hyz strands with terminal
hydroxymethyl15–17 and acryloyl18 arms which uncoil to form
Department of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand.
E-mail: lhanton@chemistry.otago.ac.nz
†Electronic supplementary information (ESI) available: Crystallographic data for
AB, L1 and 1–5 including a discussion of how disorder was handled, pictorial
views with thermal ellipsoids at the 50% probability level and selected bond
lengths and angles in tabulated form. CCDC 976898–976904. For ESI and crystallo-
graphic data in CIF or other electronic format see DOI: 10.1039/c3dt53559b
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linear complexes when reacted with excess Cu(II), Pb(II), Zn(II) while a [4 × 4] grid complex was formed by employing a metal
and Ag(I) ions. The amplitude of extension, however, is to ligand ratio of 2 : 1. A tetratopic strand composed of pym–py
minimal as the ditopic ligands only contain two hyz functions units, which are known to be isostructural to pym–hyz
20
and therefore only represent two thirds of a helical turn.17 units,4,6,7 has also been reacted with Pb(SO3CF3)2
Three hyz functions are required to form a whole helical turn AgSO3CF3
and
21
in CH3CN, resulting in various grid complexes
and the extension amplitude of pym–hyz strands has been and double helicates, respectively.
shown to increase with increasing strand length.4,7
Previous studies carried out by our research group have
Therefore, we have synthesised and characterised two new shown that the addition of terminal hydroxymethyl and acryl-
tetratopic pym–hyz strands containing terminal hydroxymethyl oyl arms to ditopic pym–hyz ligands affects the outcome of
(L1) and acryloyl (L2) arms (Scheme 1). These ligands con- self-assembly at low metal to ligand ratios as these groups
tained four hyz functions and therefore existed as 1 and 1/3 crowd the bound metal ions in both a steric and coordinative
helical turns. While examples of tetratopic pym–hyz strands fashion.15–18 The extent to which the supramolecular structure
exist in the literature4,7,19 they do not contain groups is affected by the additional groups is dependent on the size of
appended to their terminal pyridine (py) rings. Furthermore, the metal ion as well as the counteranion of the metal salt and
to date, the coordination chemistry of tetratopic pym–hyz even the choice of solvent.
strands has only been studied with respect to Pb(SO3CF3)2.4 In
Therefore we endeavoured to investigate the interactions of
those studies an excess amount of Pb(II) ions resulted in the L1 and L2 with Pb(II), Zn(II), Cu(II) and Ag(I) salts in both
uncoiling of the tetratopic ligand to form linear complexes, CH3CN and CH3NO2 in a range of metal to ligand ratios. It was
discovered that linear M4LA8 complexes (where M = Pb(II),
−
−
Zn(II), or Cu(II); L = L1 or L2; and A = ClO4−, SO3CF3 or BF4
)
could be synthesised through reacting L1 or L2 with an excess
quantity of Pb(II), Zn(II) or Cu(II) ions, while the only complexes
that could be synthesised with Ag(I) ions were Ag2L2A2 double
helicates. The formation of Ag2L22A2 double helicates was
unexpected since the steric bulk of the acryloyl arms prevented
their formation with the modified ditopic pym–hyz ligand.18
The addition of Pb(II) ions to L1 or L2 in a 2 : 1 metal to ligand
ratio resulted in horse-shoe shaped Pb2LA4 complexes as
opposed to [4 × 4] grids. A twisted Cu3L2(SO3CF3)6 was also
crystallised from a solution of the linear Cu4L2(SO3CF3)8
complex. Herein we report the synthesis and characterisation
of these two new tetratopic ligands and the solution phase and
solid state structures of their various complexes.
Results and discussion
Organic synthesis
The tetratopic, hydroxymethyl terminated ligand L1 was syn-
thesised through a double condensation reaction between
6-hydroxymethyl-2-pyridinecarboxaldehyde, 2-methyl-2-[6-(1-
methylhydrazinyl)-4-pyrimidinyl]hydrazine (AB) and 2-phenyl-
4,6-pyrimidinedicarboxaldehyde (C) in a 2 : 1 molar ratio. The
ligand was then reacted with acryloyl chloride in the presence
of triethylamine22 to convert the terminal hydroxymethyl arms
into acryloyl arms, producing ligand L2 (Scheme 1).
AB was first synthesised by reacting 6-hydroxymethyl-2-
pyridinecarboxaldehyde (A) and 4,6-bis(1-methylhydrazino)-2-
methylpyrimidine (B) in a 1 : 1 molar ratio in EtOH. The
double condensation reaction, which would have produced the
undesired ditopic ligand,7 was avoided by adding a dilute solu-
tion of A dropwise to a concentrated solution of B, in order to
maintain the molar excess of B in solution, and by performing
the reaction at room temperature. The low solubility of AB in
EtOH at room temperature meant that it was precipitated from
the solution as a pure white solid in high yields of 80 to 90%.
Scheme 1 The synthetic strategy employed to produce L1 and L2.
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Fig. 1 The (left) solution phase structure of AB showing the NOE corre-
lations seen in the 2D NOESY spectrum (NMR numbering) and (right) the
solid state structure of AB (crystallographic numbering).
Fig. 3 The (left) solution phase structure of L1 showing the NOE corre-
lations seen in the 2D NOESY spectrum (NMR numbering) and (right) the
solid state structure of L1 (crystallographic numbering; hydrogens
removed for clarity).
transoid pym–hyz and hyz–py bonds (Fig. 3). The H5 and H14
signals occurred in the 1H NMR spectrum at 8.49 and
7.31 ppm, respectively, due to deshielding from the adjacent
transoid pym–hyz linkages.7 The folding of L1 into a helix also
resulted in shielding of the terminal py protons, resulting
in their signals appearing at lower chemical shifts than in the
1H NMR spectrum of the non-helical ditopic hydroxymethyl
terminated pym–hyz strand.17
Crystals of L1 were grown by the slow diffusion of diethyl
ether into a CH2Cl2 solution of the ligand. The solid state
structure of these crystals was that of a helix with 1 and 1/3
turns (Fig. 3), a helical pitch of 3.6 Å, and a length of 3.9 Å
(measured from the centroid of the N1 py ring to the mean
plane of the N16 py ring). The helix was stabilised by π–π stack-
ing interactions between the overlapping py and pym rings
[centroid to centroid distances of 3.504(5) and 3.545(6) Å from
the N1 py ring to the N12 pym ring, and from the N16 py ring
to the N4 pym ring, respectively]. The added hydroxymethyl
arms resulted in the aggregation of L1 into quartets of mole-
cules through intermolecular H-bonding between O1 and N1,
and O2 and N16, with O1–H1⋯N1 and O2–H2⋯N16 distances
of 2.343(10) and 2.074(12) Å, respectively [corresponding to
O1⋯N1 and O2⋯N16 distances of 2.762(9) and 2.813(10) Å,
respectively; Fig. 4].
Fig. 2 View of two molecules of AB organised as dimers due to self
complementary intermolecular H-bonding between O1 and N1 (sym-
metry codes A: 1 − x, 1 − y, 1 − z).
The white precipitate produced microanalytical results con-
sistent with the formula of AB·1/2H2O. The ESMS spectrum
showed peaks due to the [AB + Na]+ and [AB + H]+ molecular
ions. The IR spectrum showed a CvN stretching mode at
1566 cm−1, confirming the formation of the imine bond
between A and B. A broad O–H stretching mode at 3167 cm−1
and a N–H stretching mode at 3332 cm−1 indicated the pres-
ence of the hydroxymethyl arm and hydrazine functional
groups of AB. The transoid–transoid conformation of the pym–
hyz–py bond of AB was evident from the lack of correlations
between H5 and H9, and H10 and H12 in the 2D NOESY NMR
spectrum. The solution phase conformation was consistent
with the solid state structure of AB, determined by X-ray ana-
lysis of crystals grown by the slow evaporation of the CDCl3
NMR solution (Fig. 1). The hydroxymethyl arms were involved
in self-complementary, intermolecular H-bonding, which
linked adjacent molecules of AB together as dimers. The O1–
H1⋯N1 distance was 2.203(3) Å, corresponding to an O1⋯N1
distance of 2.836(3) Å (Fig. 2).
AB was then refluxed with C in a 2 : 1 molar ratio in EtOH,
resulting in the formation of L1, which precipitated from the
solution as a pure white solid in high yields between 80 and
85% (Scheme 1). The microanalytical results for this solid
matched the formula of L1·H2O. The molecular ions [L1 + Na]+
and [L1 + H]+ were identified in the ESMS spectrum. The O–H
and CvN stretching modes gave peaks in the IR spectrum at
3373 and 1559 cm−1, respectively. The 2D NOESY NMR spec-
trum showed that the molecule adopted a helical shape with
The hydroxymethyl arms of L1 were converted into acryloyl
groups by reacting L1 with an excess quantity of acryloyl chlor-
ide in the presence of triethylamine.22 The limited solubility of
L1 in CH2Cl2 required that the reaction be carried out at 50 °C.
Following the removal of excess acrylic acid and protonated tri-
ethylamine with aqueous washings, L2 was isolated as a crude
brown solid residue. Washing this residue with acetone
resulted in L2 as a pure off-white solid, the microanalytical
results of which were consistent with the formula for L2. The
ESMS spectrum showed a peak corresponding to the [L2 + Na]+
molecular ion. The IR spectrum showed CvO and CvN
1
stretching modes at 1728 and 1561 cm−1, respectively. The H
NMR spectrum of L2 was very similar to that of L1, with the
exception of the extra acryloyl proton signals which occurred
as a series of double doublets between 5.92 and 6.54 ppm. The
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Fig. 5 Summary of the metal complexes formed from L1 and L2 (where
M = Pb(II), Zn(II), or Cu(II); L = L1 or L2; and A = ClO4−, SO3CF3− or BF4−).
Zn(SO3CF3)2, at which point the solution contained a mixture
of complexes. A ratio of 10 : 1 was needed for the exclusive for-
mation of the linear Zn4L(SO3CF3)8 complexes. The ligands
were also reacted with Zn(BF4)2; however, complete dissolution
was not achieved at any metal to ligand ratio. Reacting either
of the ligands with the Cu(II) salts resulted in complete dissol-
ution and the formation of Cu4LA8 complexes at a 4 : 1 metal
to ligand ratio; however, attempts to crystallise the Cu4L2-
(SO3CF3)8 complex resulted in crystals of a L2 complex co-
ordinated with only three Cu(II) ions. This suggested an equili-
brium process in which Cu(II) ions were exchanged between
the Cu4L2(SO3CF3)8 complex and the CH3CN solvent. The Ag(I)
salts only required a 1 : 1 metal to ligand ratio to completely
convert L1 or L2 into the Ag2L2A2 double helicates. Addition of
excess Ag(I) to these complexes had no effect on the compo-
sition of the solutions.
Analysis of L1 and L2 complexes. The CH3CN solutions
were stirred with diethyl ether, resulting in the precipitation of
the complexes as powders, which were then isolated by fil-
tration and dried in vacuo. In the cases of the Pb(II), Zn(II) and
Cu(II) complexes the microanalytical results for the solids sup-
ported the expected formula; however, the results showed that
several of the complexes were hydrated or solvated with
CH3CN. The microanalytical results for the Ag2L2A2 complexes
indicated that their solid precipitates also contained small por-
tions of uncoordinated AgSO3CF3 and AgBF4, despite extensive
washings with diethyl ether.
The ESMS spectra of the complexes typically only showed a
peak due to either of the [L + Na]+ molecular ions; however,
the spectrum of the Pb4L1(ClO4)8 complex also showed peaks
due to the [Pb2L1(ClO4)3]+ and [Pb2L1–2H]2+ molecular ions.
Additional peaks in the spectra of the Zn4L1(SO3CF3)8 and
Cu4L1(ClO4)8 complexes were due to the [Zn2L1(SO3CF3)3]+,
[Zn2L1(SO3CF3)2]2+, [CuL1(ClO4)]+ and [Cu2L1–2H]2+ molecular
ions. The ESMS spectra of the Ag(I) complexes of L1 and L2
all showed peaks due to the [AgL]+ molecular ions, while
the Ag2L12(SO3CF3)2 complex also showed peaks due to the
[Ag2L12(SO3CF3)]+ and [Ag2L1(SO3CF3)]+ ions.
Fig. 4 View of the H-bonding which links one molecule of L1 to three
others (hydrogens omitted for clarity; symmetry codes A: 1/2 − x, −1/2 −
y, 1/2 − z; B: −3/4 + x, , 1.25 − z; C: 1/4 − x, 3/4 + y, 1.25 − z).
NOE correlations of L2 showed that it also adopted a helical
shape in solution with transoid pym–hyz and py–hyz bonds,
analogous to L1 (Fig. 3).
Synthesis and structures of L1 and L2 complexes
The coordination chemistry of tetratopic pym–hyz strands has
previously only been probed by reactions with Pb(SO3CF3)2 in
CH3CN.4 In those studies a 2 : 1 metal to ligand ratio resulted
in [4 × 4] grid complexes, while a 4 : 1 ratio led to linear com-
plexes. In this study, ligands L1 and L2 were reacted with salts
of Pb(II), Zn(II), Cu(II) and Ag(I) in either CH3CN or CH3NO2.
Solutions of the metal salts were added to the ligands at elev-
ated temperatures, resulting in dissolution of the ligand upon
complexation. In contrast to the behaviour of the previously
investigated hydroxymethyl and acryloyl terminated ditopic
ligands,15,16,18 the outcomes of the reactions with L1 and L2
were not influenced by the choice of solvent. As a result
CH3CN was the solvent primarily used to produce complexes
for analysis. Reacting the tetratopic ligands with an excess
of Pb(ClO4)2·3H2O, Pb(SO3CF3)2·H2O, Zn(SO3CF3)2, Cu(ClO4)2·
6H2O or Cu(SO3CF3)2·4H2O resulted in linear complexes of
type M4LA8 (where M = Pb(II), Zn(II), or Cu(II); L = L1 or L2; and
−
A = ClO4−, SO3CF3 or BF4−). Horse-shoe shaped Pb2LA4 com-
plexes were formed by reacting L1 or L2 with Pb(II) ions in a
2 : 1 metal to ligand ratio, while the only complexes formed
through reacting the ligands with AgSO3CF3 or AgBF4 were
Ag2L2A2 double helicates (Fig. 5).
The metal to ligand ratios required to achieve complete
conversion of the ligands to the linear complexes differed
depending on the metal ion employed. Complete dissolution
of L1 and L2 was achieved with either Pb(II) salt at a metal to
ligand ratio of 2 : 1; however, a 4 : 1 ratio was required for the
synthesis of the linear Pb4LA8 complexes. A ratio of 4 : 1 was
necessary for complete dissolution of the ligands when using
The IR spectra of the L1 complexes showed that the coordi-
nation of Pb(II) and Ag(I) ions to L1 shifted the CvN stretching
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mode from 1559 cm−1 to between 1551 and 1541 cm−1. In con- rotation of the pym–hyz linkages from transoid to cisoid
trast, the coordination of Zn(II) and Cu(II) ions barely affected caused upfield shifts in the positions of the H5 and H14 pym
the frequency of the L1 CvN stretching mode, which signals.4 The binding of metal ions to coordination sites
occurred between 1559 and 1556 cm−1. All of the complexes of resulted in downfield shifts for the hyz and py proton signals.
L2 showed a decrease in frequency of the CvN stretching The latter were further shifted downfield due to the removal of
mode from 1561 cm−1 to between 1556 and 1540 cm−1. The shielding π–π stacking interactions upon the uncoiling of the
Pb(II) and Cu(II) complexes of L2 also showed a decrease in ligand strands.4 Based on the downfield shift of the hydroxy-
frequency of the CvO stretching mode from 1728 cm−1 to methyl signals of L1, and the lack of movement of the acryloyl
between 1720 and 1707 cm−1. The coordination of metal arm signals of L2, upon the formation of the linear complexes,
ions to L1 did not have a unified effect on the O–H stretching it appeared that the hydroxymethyl arms were coordinated to
mode, with the frequencies ranging between 3505 the terminal Pb(II) and Zn(II) ions while the acryloyl arms were
and 3357 cm−1. All of the complexes showed stretching modes not. This coordinative behavior was identical to that of
due to their ClO4−, SO3CF3− or BF4− counterions between 1047 the ditopic hydroxymethyl and acryloyl ditopic pym–hyz
and 1052, 1272 and 1211, and 1039 and 1037 cm−1
respectively.
,
strands.16,18
Several of the proton signals in the H NMR spectra of the
1
The Cu(II) complexes of L1 and L2 were also analysed by Pb4LA8 complexes were significantly broadened when a metal
UV-Vis spectroscopy, with each of their spectra showing a to ligand ratio of 4 : 1 was employed, indicating that the linear
single broad d–d transition with a λmax of either 690 or 691 nm complexes were rapidly exchanging with other complex species
for the Cu4L1(ClO4)8 and Cu4L1(SO3CF3)8 complexes, or 684 or in solution. The broadened signals originated from the pym
687 nm for the Cu4L2(ClO4)8 and Cu4L2(SO3CF3)8 complexes, and hyz protons surrounding the innermost pym–hyz–pym
respectively. The wavelengths of these transitions were consist- coordination pockets, and the protons of the phenyl ring on
ent with Cu(II) ions surrounded by N donors in either a the central pym, which suggested that the Pb(II) ions in these
distorted trigonal bipyramidal or distorted octahedral coordination pockets were more labile than those in the term-
environment.23 Their extinction coefficients of 449, 417, 546 inal pym–hyz–py pockets. Decreasing the temperature from
and 508 L mol−1 cm−1, respectively, were roughly twice the 298 to 243 K allowed for the resolution of the different
values of the d–d transitions recorded for the linear Cu(II) com- complex signals. Increasing the metal to ligand ratio shar-
plexes of the hydroxymethyl17 and acryloyl18 terminated pened the signals significantly as the excess ions shifted the
ditopic pym–hyz ligands.
equilibrium further towards the linear Pb4LA8 species (Fig. 7).
NMR spectroscopy of L1 and L2 complexes. 1H and 2D In contrast, the addition of Zn(SO3CF3)2 to L1 or L2 in a
ROESY NMR spectroscopy showed that the Pb4LA8 and Zn4L- 4 : 1 metal to ligand ratio resulted in complicated 1H NMR
(SO3CF3)8 complexes were linear in shape, with cisoid pym– spectra showing multiple complexes slowly exchanging in solu-
hyz and hyz–py linkages and metal ions occupying each of the tion. Increasing the metal to ligand ratio to 10 : 1 resulted in a
coordination pockets (Fig. 6). The uncoiling of the L1 and L2 dramatic simplification of the spectra as the multiple species
ligands upon the coordination of Pb(II) or Zn(II) ions resulted in solution were converted to the linear Zn4L(SO3CF3)8
in several distinctive changes in the 1H NMR spectrum. The complexes.
Fig. 6 The solution phase conformations of the Pb(II), Zn(II) and Ag(I) complexes of L1 and L2 as deduced by NMR spectroscopy, showing their NOE
correlations (NMR numbering; transoid and cisoid pym–hyz and hyz–py bonds are highlighted in blue or black, respectively).
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Fig. 7 The aromatic region of the 1H NMR spectra of the Pb4L1(ClO4)8
complex at different metal to ligand ratios and temperatures (NMR
numbering).
The ROESY spectra of the Pb2LA4 complexes showed they
consisted of a horse shoe shaped ligand backbone with Pb(II)
ions occupying the terminal pym–hyz–py coordination sites.
As a result these sites adopted the cisoid–cisoid conformation,
while the vacant pym–hyz–pym sites retained their transoid–
transoid conformation (Fig. 6). The chemical shifts of the H5
and H14 pym signals were similar to the native ligands due
to the incomplete isomerisation of the pym–hyz bonds in the
Pb2LA4 complexes. The partial unfolding of the ligand
removed the π–π interactions between the heterocyclic rings,
resulting in a downfield shift of the py signals. The selective
binding of the Pb(II) ions to the terminal coordination sites
also resulted in downfield shifts to the H19 hyz signals, while
the H11 hyz signals appeared at chemical shifts similar
to those seen in the spectra of L1 and L2. As with the linear
complexes it appeared that the hydroxymethyl arms were co-
ordinated to the Pb(II) ions in the Pb2L1A4 complexes, while
the acryloyl arms did not interact with the metal ions in the
Pb2L2A4 complexes.
Fig. 8 View of the cation molecules of (top) complex 1 and (bottom)
complex
2 (hydrogen atoms omitted for clarity; crystallographic
numbering).
[Pb4L1(SO3CF3)8]2·6CH3CN·H2O (2). The horse-shoe shaped
Pb2L1(ClO4)4 complex was crystallised from CH3CN in a
similar fashion, the analysis of which resulted in the structure
of [Pb2L1(ClO4)2(CH3CN)(H2O)](ClO4)2·2CH3CN·C4H10O·H2O
(3). Attempts to crystallise the Cu4L2(SO3CF3)8 complex
through the diffusion of diethyl ether resulted in crystals
of the twisted [Cu3L2(SO3CF3)3(CH3CN)2(H2O)](SO3CF3)3·
2CH3CN·H2O (4) complex instead. The slow diffusion of
diethyl ether into a CH3CN solution of the double helicate
Ag2L12(SO3CF3)2 complex yielded crystals of [Ag2L12](SO3CF3)2·
CH3CN·H2O (5).
Complexes 1 and 2 consisted of linear L1 molecules with
cisoid pym–hyz bonds and Pb(II) ions occupying each coordi-
nation pocket, similar to the solution phase Pb4L1A8 structures
identified by NMR spectroscopy (Fig. 8). The length of each
complex was 27.8 Å and 28.1 Å, respectively, which when com-
pared to the length of L1 corresponded to an extension ampli-
tude of 24.2 Å. This value was comparable to that of the
unmodified tetratopic pym–hyz strand reported in the litera-
ture upon coordination with Pb(SO3CF3)2.4 Also similar to that
literature complex was the dimeric arrangement of complex 2
The 1H NMR spectra of the Ag(I) and L1 or L2 solutions
showed that the Ag2L2A2 double helicates were the only species
present in all metal to ligand ratios from 1 : 1 and above. The
coordination of the Ag(I) ions to the py and hyz N donors of
the terminal coordination sites resulted in the hyz–py bonds
adopting a cisoid conformation and the pym–hyz bonds retain-
ing their transoid conformations (Fig. 6). The selective binding
of Ag(I) ions to the more basic py N donors, at the expense of
the pym N donors, was in keeping with their soft classifi-
cation.24,25 The 2D ROESY spectra showed that the H5 and
H14 pym signals were orientated towards each other in the
interior of the helicate. The close proximity of the two inter-
twined L1 or L2 molecules resulted in shielding of these
protons. The protons from the hydroxymethyl and acryloyl
arms were also shielded; however, the chemical equivalence of
the methylene protons suggested that the arms were able to
freely rotate in solution.
−
due to several of the SO3CF3 anions bridging between the
Pb(II) ions bound to neighbouring L1 molecules (Fig. 8). While
the two L1 molecules of 2 were not crystallographically related
their bond lengths and angles were equivalent within experi-
mental error. Each of the Pb(II) ions in complexes 1 and 2 were
bound to the three N donors of each coordination pocket. The
hydroxymethyl arms were consistently coordinated to the Pb(II)
ions in the terminal pockets, as was the case with the ditopic
hydroxymethyl pym–hyz ligands.16 The vacancies in the coordi-
nation spheres of the Pb(II) ions were satisfied with H2O mole-
−
−
cules, ClO4 or SO3CF3 anions, and stereochemically active
lone pairs of electrons.26
X-ray crystallography of L1 and L2 complexes
The structure of complex 3 was also similar to its solution
phase analogue as it was a horse-shoe shaped complex with
Pb(II) ions bound only in the terminal pym–hyz–py coordination
pockets (Fig. 9). Complex 3 was therefore vastly different from
Crystals were grown of the linear Pb4L1(ClO4)8 and Pb4L1-
(SO3CF3)8 complexes through the slow diffusion of diethyl
ether into CH3NO2 and CH3CN solutions, respectively, yielding
the structures [Pb4L1(ClO4)7(H2O)](ClO4)·4CH3NO2 (1) and
8210 | Dalton Trans., 2014, 43, 8205–8218
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Paper
pym N donors resulted in transoid–cisoid pym–hyz–py bonds
and transoid–transoid pym–hyz–pym linkages. Ag1 was also
bound to the hydroxymethyl arm of one of the L1 molecules
and resulted in a five coordinated distorted square pyramidal
environment (τ5 = 0.36).28 In contrast, Ag2 was not bound to
either hydroxymethyl arm and existed in a four coordinated,
distorted, tetrahedral geometry (τ4 = 0.52).29 The resulting
asymmetry was the only major deviation of complex 5 from the
solution phase Ag2L12A2 structure. The presence of the
hydroxymethyl arms also prevented any intermolecular Ag(I)–
Ag(I) interactions, which are a common feature in Ag(I) double
helicates made from unmodified pym–hyz25 and pym–py21
ligands.
Fig. 9 View of the cation molecules of (left) complex 3 and (right)
complex 4 (hydrogens omitted for clarity; crystallographic numbering).
the [4 × 4] square grids which were previously the outcome of
reacting Pb(SO3CF3)2 with tetratopic pym–hyz4 and pym–py20
strands in a 2 : 1 metal to ligand ratio. Two factors may have
contributed to the inability of L1 to form a grid structure: (i)
the steric bulk of the phenyl ring appended to the central pym,
and (ii) the crowding of the Pb(II) ions due to the coordination
of the hydroxymethyl arms, which may have prevented the
ions from binding to more than one L1 molecule.16–18,27
Experimental section
Materials and instrumentations
All starting materials, reagents and metal salts were purchased
from commercial sources and were used as received without
further purification, with the exceptions of Pb(SO3CF3)2·H2O
and Cu(SO3CF3)2·4H2O which were produced through the
treatment of 2PbCO3·Pb(OH)2 and CuCO3·Cu(OH)2·H2O,
respectively, with aqueous triflic acid. The precursors 6-hydroxy-
Complex 4 was another example of a pym–hyz strand un-
saturated with metal ions, as it consisted of three Cu(II) ions
occupying three of the four coordination pockets of L2 (Fig. 9).
While the pym–hyz bonds coordinated to the Cu(II) ions were
rotated to their cisoid conformation, the pym–hyz bond of the
vacant pocket retained its transoid conformation. This
imparted a twisted shape to complex 4. The Cu(II) ions were co-
ordinated to the three N donors of each pocket, but not to the
terminal acryloyl arms. Each Cu(II) ion existed in a five co-
ordinated distorted square pyramidal environment (τ5 values
of 0.27, 0.07 and 0.21 for Cu1, Cu2, and Cu3, respectively)28
methyl-2-pyridinecarboxaldehyde
(A),30
4,6-bis(1-methyl-
hydrazino)-2-methylpyrimidine (B),31 4,6-dimethyl-2-phenyl-
pyrimidine32 and 2-phenyl-4,6-pyrimidinedicarboxaldehyde
(C)33 were prepared according to their literature methods. All
solvents were used as received, and were of LR grade or better.
Microanalyses were carried out in the Campbell Micro-
analytical Laboratory, University of Otago. All measured micro-
analysis results had an uncertainty of 0.4%. H and 13C NMR
1
spectra and two dimensional (gCOSY, NOESY, ROSEY, HSQC,
gHMBC) spectra were collected on a 500 MHz Varian UNITY
INOVA spectrometer at 298 K. Spectra were referenced to the
internal solvent signal, with chemical shifts reported in δ units
(ppm). Electrospray Mass Spectrometry (ESMS) was carried out
−
with additional bonds to SO3CF3 anions, CH3CN or H2O
molecules. Both compounds 3 and 4 were examples of archi-
tectures previously unseen for tetratopic pym–hyz complexes.
The Ag(I) double helicate complex 5 consisted of two helical
L1 molecules sharing two Ag(I) ions between their terminal
pym–hyz–py coordination pockets (Fig. 10). The preferential
binding of the Ag(I) ions to the hyz and py N donors over the
on
a Bruker microTOFQ instrument (Bruker Daltronics,
Bremen, Germany) by employing direct infusion into an ESI
source in positive mode. Infrared (IR) spectra were recorded on
a Bruker Alpha-P ATR-IR spectrometer. UV-Vis spectra were col-
lected on an Agilent 8453 spectrophotomer against a CH3CN
background using quartz cells with a 1 cm path length.
6-Hydroxymethyl-2-pyridinecarboxaldehyde, 2-methyl-2-[6-
(1-methylhydrazinyl)-4-pyrimidinyl]hydrazone (AB). A solution
of 6-hydroxymethyl-2-pyridinecarboxaldehyde (A; 2.00 g,
14.6 mmol) in EtOH (300 mL) was added dropwise to a stirring
solution of 4,6-bis(1-methylhydrazino)-2-methylpyrimidine (B;
2.71 g, 14.9 mmol) in EtOH (70.0 mL), then stirred for 20 h,
resulting in the precipitation of AB as a white solid. The
mixture was filtered and the precipitate was washed with EtOH
and dried in vacuo (3.65 g, 83%): M.p. 180–183 °C. Anal.
Found: C 54.22; H 6.20; N 31.46. Calc. for C14H19N7O·1/2H2O:
C 54.18; H 6.50; N 31.59. 1H NMR (500 MHz, CDCl3) δ/ppm:
7.87 (1H, d, J = 7.8 Hz, H12), 7.75 (1H, s, H10), 7.68 (1H, t, J =
7.8 Hz, H13), 7.14 (1H, d, J = 7.6 Hz, H14), 6.80 (1H, s, H5),
Fig. 10 View of the [Ag2L12]2+ cation of complex 5.
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Dalton Transactions
4.75 (2H, s, H17), 4.17 (2H, bs, NH2), 3.64 (3H, s, H8), 3.30 7.7 Hz, H22), 6.90 (2H, d, J = 7.5 Hz, H23), 6.54 (2H, dd, J =
(3H, s, H9), 2.45 (3H, s, H7). 13C NMR (500 MHz, CDCl3) 1.3, 17.3 Hz, H28a), 6.26 (2H, dd, J = 10.5, 17.3 Hz, H27), 5.92
δ/ppm: 166.3 (C2), 165.4 (C6), 162.8 (C4), 158.7 (C15), 154.1 (2H, dd, J = 1.3, 10.5 Hz, H28b), 5.21 (4H, s, H25), 3.65 (6H, s,
(C11), 137.2 (C13), 136.2 (C10), 119.6 (C14), 118.2 (C12), 82.0 H12), 3.49 (6H, s, H18), 2.42 (6H, s, H17). 13C NMR (500 MHz,
(C5), 64.3 (C17), 40.0 (C9), 30.0 (C8), 26.4 (C7). ESMS m/z CDCl3) δ/ppm: 166.0 (C26), 165.6 (C16), 165.2 (C2), 162.5
Found: 302.1705, 324.1527. Calc. for C14H20N7O+: 302.1724. (C16), 162.4 (C4/6), 162.2 (C13), 154.9 (C24), 154.1 (C20), 137.9
Calc for C14H19N7ONa+: 324.1543. Selected IR ν/cm−1: 3332m (C7), 136.7 (C22), 136.4 (C19), 135.3 (C11), 131.8 (C28), 131.0
(NH), 3167br (OH), 2936m (CH), 1621s (NH), 1588s, 1566s (C10), 128.9 (C9), 128.4 (C8), 128.3 (C27), 120.0 (C23), 118.6
(CvN), 1539s, 1485s, 1476s, 1456s, 1440s, 1417s, 1392s, 1292s, (C21), 107.1 (C5), 87.2 (C14), 66.8 (C25), 30.3 (C12), 29.9 (C18),
1268s, 1236s, 1217s, 1155s, 1091s, 1027s. Colourless crystals 26.2 (C17). ESMS m/z Found: 909.3705. Calc. for
suitable for X-ray diffraction were grown by the slow evapor- C46H46N16O4Na+: 909.3786. Selected IR ν/cm−1: 2920m (CH),
ation of a CDCl3 solution of AB.
1728s (CvO), 1633m (CvC), 1589s, 1561s (CvN), 1525s,
2-Phenylpyrimidine-4,6-dicarboxaldehyde, bis[methyl[6-[1- 1482s, 1429s, 1410s, 1369s, 1292s, 1238s, 1215s, 1166s, 1092s,
methyl-2-(6-hydroxy-methylpyridin-2-ylmethylene)-hydrazino]- 1044s.
2-methylpyrimidin-4-yl]hydrazone] (L1). AB (2.15 g, 7.16 mmol)
Pb4L1(ClO4)8. A solution of Pb(ClO4)2·3H2O (23.2 mg,
and 2-phenyl-4,6-pyrimidine-dicarboxaldehyde (C; 0.727 g, 0.0504 mmol) in CH3CN (5.00 mL) was added to L1 (9.65 mg,
3.42 mmol) were refluxed in EtOH (250 mL) for 6 h resulting 0.0124 mmol) and stirred at 70 °C for 1 h resulting in the dis-
in the precipitation of L1 as a white solid. The mixture was fil- solution of L1 and the formation of an orange solution. The
tered and the precipitate was washed with EtOH and dried addition of diethyl ether (20.0 mL) resulted in the precipitation
in vacuo (2.31 g, 87%): Anal. Found: C 60.19; H 5.36; N 28.40. of an orange solid, which was filtered, washed with diethyl
1
Calc. for C40H42N16O2·H2O: C 60.29; H 5.57; N 28.12. H NMR ether and dried in vacuo (15.5 mg, 52%): Anal. Found: C 19.54;
(500 MHz, CDCl3) δ/ppm: 8.52 (2H, m, H8), 8.49 (1H, s, H5), H 2.32; N 9.00. Calc. for C40H42N16O34Cl8Pb4·4H2O: C 19.41; H
1
7.78 (2H, s, H11), 7.64 (2H, d, J = 7.7 Hz, H21), 7.53 (3H, m, 2.04; N 9.05. H NMR (500 MHz, CD3CN) δ/ppm: 8.89 (2H, s,
H9/H10), 7.44 (2H, s, H19), 7.31 (2H, s, H14), 7.11 (2H, t, J = H11), 8.79 (2H, s, H19), 8.38 (1H, s, H5), 8.20 (2H, t, J = 7.8 Hz,
7.6 Hz, H22), 6.81 (2H, d, J = 7.5 Hz, H23), 4.61 (4H, s, H25), H22), 7.97 (2H, d, J = 7.5 Hz, H21), 7.97 (2H, m, H8), 7.85 (3H,
3.92 (2H, bs, H26), 3.57 (6H, s, H12), 3.49 (6H, s, H18), 2.46 m, H9/10), 7.69 (2H, d, J = 7.9 Hz, H23), 6.83 (2H, s, H14), 6.12
(6H, s, H17). 13C NMR (500 MHz, CDCl3) δ/ppm: 165.7 (C16), (2H, br, H26), 5.33 (4H, s, H25), 3.85 (6H, s, H12), 3.78 (6H, s,
165.2 (C2), 162.5 (C15), 162.4 (C4, C6), 162.0 (C13), 158.5 H18), 2.79 (6H, s, H17). 13C NMR (500 MHz, CD3CN) δ/ppm:
(C24), 153.5 (C20), 136.4 (C7), 136.4 (C19), 134.9 (C11), 130.9 168.0 (C2), 167.4 (C16), 162.0 (C24), 161.0 (C15), 160.2 (C4/6),
(C10), 128.8 (C9), 128.3 (C8), 119.2 (C23), 118.1 (C21), 107.1 160.0 (C13), 149.7 (C20), 145.7 (C19), 142.3 (C11), 141.7 (C22),
(C5), 87.4 (C14), 64.7 (C25), 30.1 (C12), 29.7 (C18), 26.0 (C17). 136.4 (C7), 133.1 (C9), 132.3 (C8), 128.6 (C10), 128.3 (C21),
+
ESMS m/z Found: 779.3739, 801.3561. Calc. for C40H43N16O2 : 125.2 (C23), 124.1 (C5), 88.7 (C14), 65.2 (C25), 36.5 (C12), 35.8
779.89; Calc. for C40H42N16O2Na+: 801.3569. Selected IR (C18), 26.5 (C17). ESMS m/z Found: 1491.1700, 596.1525.
+
ν/cm−1: 3373br (OH), 2919w (CH), 1589s, 1559s (CvN), Calc. for
C
40H42N16O2Pb2(ClO4)3 : 1491.1665. Calc. for
1528m, 1482s, 1455m, 1432m, 1409m, 1386m, 1369m, 1280w, C40H40N16O2Pb22+: 596.1521. Selected IR ν/cm−1: 3445br (OH),
1264w, 1236m, 1215m, 1165m, 1093w, 1042m. Colourless crys- 3070w (CH), 2924w (CH), 1636w, 1588m, 1545s (CvN), 1475m,
tals suitable for X-ray diffraction were grown by slow diffusion 1448m, 1412m, 1381m, 1292m, 1267m, 1152s, 1110s, 1089s,
of diethyl ether into a CH2Cl2 solution of L1.
1047s (ClO4−). Crystals suitable for X-ray diffraction were
2-Phenylpyrimidine-4,6-dicarboxaldehyde, bis[methyl[6-[1- grown by the slow diffusion of diethyl ether into a CH3NO2
methyl-2-(6-hydroxy-methylacryloylpyridin-2-ylmethyl-ene)- solution of Pb(ClO4)2·3H2O and L1 in a 4 : 1 metal to ligand
hydrazino]-2-methylpyrimidin-4-yl]hydrazone]
(L2). Acryloyl ratio. These crystals gave the structure [Pb4L1(ClO4)7(H2O)]-
chloride (1.00 mL, 12.3 mmol) was added dropwise to a ClO4·4CH3NO2 (1).
mixture of L1 (1.04 g, 1.33 mmol) and triethylamine (2.00 mL,
Pb4L1(SO3CF3)8. As described for Pb4L1(ClO4)8 but with
14.4 mmol) stirring in dry CH2Cl2 (250 mL) under Ar. The Pb(SO3CF3)2·H2O (112 mg, 0.220 mmol) and L1 (41.8 mg,
resulting orange solution was then stirred at 60 °C for 4 h 0.0537 mmol) in CH3CN (5.00 mL); orange solid (117 mg,
under Ar, then cooled to rt and added to H2O (50.0 mL). The 78%): Anal. Found: C 19.65; H 1.99; N 7.38. Calc. for
1
organic layer was separated and washed with H2O, saturated C48H42N16O26F24S8Pb4·8H2O: C 19.58; H 1.99; N 7.61. H NMR
NaCl solution and Na2CO3 solution before being dried over (500 MHz, CD3CN) δ/ppm: 8.94 (2H, br, H11), 8.76 (2H, s,
MgSO4. It was then rotary evaporated to dryness and the result- H19), 8.44 (1H, br, H5), 8.23 (2H, t, J = 7.8 Hz, H22), 8.11 (2H,
ing brown solid residue was stirred in acetone (10.0 mL) for br, H8), 7.96 (2H, d, J = 7.5 Hz, H21), 7.84 (3H, br, H9/H10),
1 h, resulting in the precipitation of L2 as a white solid 7.71 (2H, d, J = 7.9 Hz, H23), 6.86 (2H, br, H14), 5.35 (4H, s,
(0.839 g, 71%): Anal. Found: C 61.71; H 5.24; N 23.30. Calc. for H25), 3.86 (6H, s, H12), 3.80 (6H, s, H18), 2.82 (6H, s, H17).
C46H46N16O2·1/2H2O: C 61.66; H 5.29; N 25.01. 1H NMR 13C NMR (500 MHz, CD3CN) δ/ppm: 168.4 (br, C4/C6), 198.0
(500 MHz, CDCl3) δ/ppm: 8.55 (2H, m, H8), 8.52 (1H, s, H5), (C16), 162.7 (C24), 161.5 (C15), 160.6 (C13), 150.5 (C20), 145.7
7.85 (2H, s, H11), 7.72 (2H, d, J = 7.8 Hz, H21), 7.54 (3H, m, (C19), 142.2 (C22), 133.4 (C7), 132.3 (C8), 129.4 (C2), 128.5
H9/10), 7.52 (2H, s, H19), 7.30 (2H, s, H14), 7.12 (2H, t, J = (C21), 125.4 (C23), 88.6 (C14), 65.6 (C25), 36.9 (C12), 36.3
8212 | Dalton Trans., 2014, 43, 8205–8218
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(C18), 26.4 (C17). ESMS m/z Found: 801.3553. Calc. for (C19), 142.9 (C4/6), 142.5 (C22), 136.4 (C7), 133.8 (C28), 133.1
C40H42N16O2Na+: 801.3569. Selected IR ν/cm−1: 3379br (OH), (C9), 132.3 (C10), 129.6 (C21), 128.5 (C8), 128.2 (C23), 127.8
1588m, 1542s (CvN), 1476m, 1448m, 1383m, 1358m, 1211s (C27), 124.3 (C5), 88.8 (C14), 65.9 (C25), 36.6 (C12), 35.9 (C18),
(SO3CF3−), 1149s, 1049s, 1017s. Crystals suitable for X-ray diffr- 26.1 (C17). ESMS m/z Found: 909.3699, 887.3966. Calc. for
action were grown by the slow diffusion of diethyl ether into a C46H46N16O4Na+: 909.3785. Calc. for C46H47N16O4+: 887.3966.
CH3CN solution of Pb(SO3CF3)2·H2O and L1 in a 4 : 1 metal to Selected IR ν/cm−1: 3406w, 3064w (CH), 1707w (CvO), 1587m,
ligand ratio. These crystals gave the structure [Pb4L1- 1543s (CvN), 1478m, 1460m, 1449m, 1408m, 1384m, 1295m,
(SO3CF3)8]2·6CH3CN·H2O (2).
1264m, 1153m, 1043s (ClO4−).
Pb2L1(ClO4)4. As described for Pb4L1(ClO4)8 but with
Pb4L2(SO3CF3)8. As described for Pb4L1(ClO4)8 but with
Pb(ClO4)2·3H2O (94.4 mg, 0.205 mmol) and L1 (79.3 mg, Pb(SO3CF3)2·H2O (135 mg, 0.258 mmol) and L2 (56.6 mg,
0.102 mmol) in CH3CN (10.0 mL); yellow solid (98.7 mg, 61%): 0.0638 mmol) in CH3CN (10.0 mL); orange solid (116 mg,
Anal. Found:
C
30.06;
H
3.09;
N
13.83. Calc. for 62%): Anal. Found: C 22.39; H 1.98; N 7.48. Calc. for
C40H42N16O18Cl4Pb2·H2O: C 29.86; H 2.76; N 13.93. 1H NMR C54H46N16O28Pb4S8F24·H2O: C 22.16; H 1.65; N 7.66. H NMR
(500 MHz, CD3CN/(CD3)2CO) δ/ppm: 8.48 (2H, s, H19), 8.44 (500 MHz, CD3CN) δ/ppm: 8.94 (4H, s, H11/H19), 8.43 (1H, s,
(2H, m, H8), 8.33 (1H, s, H5), 7.95 (2H, s, H11), 7.80 (2H, t, J = H5), 8.29 (2H, t, J = 7.8 Hz, H22), 8.07 (2H, d, J = 7.9 Hz, H21),
7.7 Hz, H22), 7.53 (2H, d, J = 7.7 Hz, H23), 7.50 (2H, m, H21), 8.07 (2H, m, H8), 7.88 (2H, d, J = 7.7 Hz, H23), 7.88 (3H, m,
7.47 (3H, m, H9/10), 7.27 (2H, s, H14), 6.49 (2H, s, H26), 5.34 H9/10), 6.94 (2H, s, H14), 6.51 (2H, d, J = 17.3 Hz, H28a), 6.34
(4H, s, H25), 3.71 (6H, s, H12), 3.60 (6H, s, H18), 2.74 (6H, s, (2H, dd, J = 10.4, 17.3 Hz, H27), 6.00 (2H, d, J = 10.6 Hz,
H17). ESMS m/z Found: 801.3659. Calc. for C40H42N16O2Na+: H28b), 5.54 (4H, s, H25), 3.88 (6H, s, H12), 3.81 (6H, s, H18),
801.3569. Selected IR ν/cm−1: 3389br (OH), 2921w (CH), 2.83 (6H, s, H17). ESMS m/z Found: 909.3785. Calc. for
1576m, 1551s (CvN), 1478m, 1447m, 1407m, 1369m, 1315m, C46H46N16O4Na+: 909.3781. Selected IR ν/cm−1: 3356w, 3066w
1285m, 1230m, 1194m, 1090s, 1042s (ClO4−). Crystals (CH), 1710w (CvO), 1590m, 1576m, 1545s (CvN), 1481m,
suitable for X-ray diffraction were grown by the slow diffusion 1461m, 1411m, 1389m, 1212s (SO3CF3−), 1149s, 1049s, 1016s.
1
of diethyl ether into a CH3CN solution of Pb(ClO4)2·3H2O
Pb2L2(ClO4)4. As described for Pb4L1(ClO4)8 but with
and L1 in a 2 : 1 metal to ligand ratio. These crystals gave the Pb(ClO4)2·3H2O (25.6 mg, 0.0556 mmol) and L2 (23.3 mg,
structure [Pb2L1(ClO4)2(CH3CN)(H2O)](ClO4)2·2CH3CN·C4H10O· 0.0263 mmol) in CH3CN (10.0 mL); yellow solid (32.8 mg,
H2O (3).
74%): Anal. Found: C31.19; H 2.82; N 12.45. Calc. for
1
Pb2L1(SO3CF3)4. As described for Pb4L1(ClO4)8 but with C46H46N16O20Cl4Pb2·4H2O: C 31.19; H 3.07; N 12.65. H NMR
Pb(SO3CF3)2·H2O (46.6 mg, 0.089 mmol) and L1 (32.2 mg, (500 MHz, CD3CN/(CD3)2CO) δ/ppm: 8.61 (2H, s H19), 8.54
0.042 mmol) in CH3CN (10.0 mL); yellow solid (45.3 mg, 60%): (3H, m, H5/8), 8.12 (2H, s, H11), 7.84 (2H, t, J = 7.9 Hz, H22),
Anal. Found:
C
28.36;
H
2.54;
N
11.81. Calc. for 7.72 (2H, d, J = 7.7 Hz, H21), 7.55 (5H, m, H9/10/23), 7.47 (2H,
C44H42N16O14F12S4Pb2·4H2O: C 28.39; H 2.71; N 12.04. 1H s, H14), 6.57 (2H, d, J = 17.2 Hz, H28a), 6.43 (2H, dd, J = 10.3,
NMR (500 MHz, CD3CN/(CD3)2CO) δ/ppm: 8.48 (2H, m, H8), 17.3 Hz, H27), 6.05 (2H, d, J = 10.3 Hz, H28b), 5.54 (4H, s,
8.42 (2H, s, H19), 8.38 (1H, s, H5), 8.00 (2H, s, H11), 7.71 (2H, H25), 3.84 (6H, s, H12), 3.64 (6H, s, H18), 2.81 (6H, s, H17).
t, J = 7.7 Hz, H22), 7.50 (5H, m, H9/10/21), 7.43 (2H, d, J = ESMS m/z Found: 909.3750. Calc. for C46H46N16O4Na+:
7.5 Hz, H23), 7.28 (2H, s, H14), 6.05 (2H, t, J = 3.5 Hz, H26), 909.3781. Selected IR ν/cm−1: 3447br, 3085w (CH), 3050w
5.30 (4H, d, J = 3.6 Hz, H25), 3.74 (6H, s, H12), 3.57 (6H, s, (CH), 1713w (CvO), 1630w (CvC), 1590m, 1576m, 1552s
H18), 2.75 (6H, s, H17). ESMS m/z Found: 801.3528. Calc. for (CvN), 1479m, 1459m, 1459m, 1408m, 1392m, 1371m,
C40H42N16O2Na+: 801.3569. Selected IR ν/cm−1: 3356br (OH), 1315m, 1289s, 1230s, 1093s, 1046s (ClO4−).
3097w (CH), 2963w (CH), 2928w (CH), 1726w, 1682w, 1589m,
1577m, 1548s (CvN), 1479m, 1445m, 1411m, 1371m, 1279s, Pb(SO3CF3)2·H2O (34.8 mg, 0.0665 mmol) and L2 (27.5 mg,
1208s (SO3CF3−), 1163s, 1117s, 1047s, 1017s.
0.0310 mmol) in CH3CN (10.0 mL); yellow solid (38.1 mg,
Pb2L2(SO3CF3)4. As described for Pb4L1(ClO4)8 but with
Pb4L2(ClO4)8. As described for Pb4L1(ClO4)8 but with Pb 65%): Anal. Found: C 31.98; H 2.64; N 11.48. Calc. for
(ClO−4)2·3H2O (135 mg, 0.289 mmol) and L2 (61.4 mg, C50H46N16O16F12S4Pb2: C 31.65; H 2.44; N 11.81. 1H NMR
0.0692 mmol) in CH3CN (10.0 mL); orange solid (136 mg, (500 MHz, CD3CN/(CD3)2CO) δ/ppm: 8.57 (2H, s, H19), 8.51
78%): Anal. Found: C 21.17; H 2.25; N 8.34. Calc. for (2H, m, H8), 8.48 (1H, s, H5), 8.06 (2H, s, H11), 7.69 (4H, m,
C46H46N16O36Pb4Cl8·4H2O: C 21.39; H 2.11; N 8.67. 1H NMR H21/22), 7.53 (3H, m, H9/10), 7.46 (2H, d, J = 7.1 Hz, H23),
(500 MHz, CD3CN) δ/ppm: 8.96 (2H, s, H19), 8.94 (2H, s, H11), 7.38 (2H, s, H14), 6.58 (2H, dd, J = 1.3, 17.3 Hz, H28a), 6.42
8.28 (1H, s, H5), 8.26 (2H, t, J = 7.8 Hz, H22), 8.07 (2H, d, J = (2H, dd, J = 10.3, 17.3 Hz, H27), 6.05 (2H, dd, J = 1.4, 10.4 Hz,
7.7 Hz, H21), 7.97 (2H, d, J = 3.6 Hz, H8), 7.86 (2H, d, J = H28b), 5.52 (4H, s, H25), 3.78 (6H, s, H12), 3.59 (6H, s, H18),
7.9 Hz, H23), 7.86 (3H, m, H9/10), 6.90 (2H, s, H14), 6.46 (2H, 2.80 (6H, s, H17). ESMS m/z Found: 909.3760. Calc. for
dd, J = 1.0, 17.3 Hz, H28a), 6.29 (2H, dd, J = 10.5, 17.3 Hz, C46H46N16O4Na+: 909.3781. Selected IR ν/cm−1: 3404w, 3075w
H27), 5.99 (2H, dd, J = 1.0, 10.5 Hz, H28b), 5.48 (4H, s, H25), (CH), 3045w (CH), 1719w (CvO), 1631w (CvC), 1590m,
3.86 (6H, s, H12), 3.80 (6H, s, H18), 2.83 (6H, s, H17). 13C NMR 1577m, 1552s (CvN), 1480m, 1458m, 1408m, 1458m, 1408m,
(500 MHz, CD3CN) δ/ppm: 167.9 (C2), 167.3 (C16), 166.3 (C26), 1371m, 1281m, 1225s (SO3CF3−), 1207s, 1160s, 1117s, 1048s,
160.3 (C13/15), 160.0 (C11), 156.8 (C24), 149.4 (C20), 147.5 1015s.
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Zn4L1(SO3CF3)8. As described for Pb4L1(ClO4)8 but with 0.0391 mmol) in CH3CN (10.0 mL); green solid (71.2 mg,
Zn(SO3CF3)2 (310 mg, 0.852 mmol) and L1 (64.7 mg, 81%): Anal. Found: C 25.47; H 2.15; N 9.86. Calc. for
0.0831 mmol) in CH3CN (5.00 mL); orange solid (126 mg, C48H42N16O26F24S8Cu4·2H2O: C 25.49; H 2.05; N 9.91. ESMS
68%): Anal. Found: C 25.00; H 2.57; N 9.33. Calc. for m/z Found: 801.3587. Calc for C40H42N16O2Na+: 801.3569.
1
C48H42N16O26F24S8Zn4·6H2O: C 24.63; H 2.33; N 9.57. H NMR Selected IR ν/cm−1: 3357br (OH), 3067w (CH), 1603m, 1557s
(500 MHz, CD3CN) δ/ppm: 8.53 (2H, s, H11), 8.38 (2H, s, H19), (CvN), 1482m, 1383m, 1220s (SO3CF3−), 1148s, 1057s, 1022s.
8.36 (1H, s, H5), 8.19 (2H, t, J = 7.8 Hz, H22), 7.86 (2H, d, J = UV-Vis λmax(ε)/nm (L mol−1 cm−1): 691 (417).
7.1 Hz, H8), 7.85 (2H, d, J = 7.9 Hz, H21), 7.80 (1H, d, J =
Cu4L2(ClO4)8. As described for Pb4L1(ClO4)8 but with
7.4 Hz, H10), 7.76 (2H, t, J = 7.4 Hz, H9), 7.63 (2H, d, J = 8.0 Cu(ClO4)2·6H2O (85.3 mg, 0.231 mmol) and L2 (47.1 mg,
Hz, H23), 6.90 (2H, s, H14), 6.81 (2H, t, J = 3.5 Hz, H26), 5.05 0.0531 mmol) in CH3CN (10.0 mL); green solid (80.4 mg,
(4H, d, J = 3.5 Hz, H25), 3.88 (6H, s, H12), 3.79 (6H, s, H18), 78%): Anal. Found: C 24.58; N 3.26; N 10.32. Calc. for
2.81 (6H, s, H17). 13C NMR (500 MHz, CD3CN) δ/ppm: 168.9 C46H46N16O36Cl8Cu4·16H2O: C 24.83; H 3.53; N 10.07. ESMS
(C2), 167.8 (C16), 159.5 (C11), 159.4 (C15), 158.6 (C4/6), 158.3 m/z Found: 909.3788. Calc. for C46H46N16O4Na+: 909.3781.
(C24), 146.1 (C20), 143.3 (C22), 137.0 (C19), 136.2 (C7), 135.0 Selected IR ν/cm−1: 3425m, 3064w (CH), 1720w (CvO), 1656w
(C11), 133.1 (C10), 131.0 (C8), 129.9 (C9), 126.0 (C21), 125.1 (CvC), 1631w, 1587m, 1552s (CvN), 1472m, 1435m, 1415m,
(C23), 123.4 (C5), 88.3 (C14), 61.7 (C25), 35.8 (C12), 34.5 (C18), 1383m, 1292m (CO), 1266m, 1155m, 1052s (ClO4−). UV-Vis
27.5 (C17). ESMS m/z Found: 1357.0799, 603.0645. Calc. λmax (ε)/nm (L mol−1 cm−1): 687 (508).
+
for C40H42N16O2Zn2(SO3CF3)3 : 1355.0784. Calc. for C40H42N16-
Cu4L2(SO3CF3)8. As described for Pb4L1(ClO4)8 but with
O2Zn2(SO3CF3)22+: 603.0629. Selected IR ν/cm−1: 3294br (OH), Cu(SO3CF3)2·4H2O (101 mg, 0.235 mmol) and L2 (49.9 mg,
1559s (CvN), 1479m, 1447m, 1383m, 1282m, 1232s 0.0563 mmol) in CH3CN (10.0 mL); green solid (96.7 mg,
(SO3CF3−), 1212s, 1149s, 1055s, 1022s.
74%): Anal. Found: C 26.44; H 2.54; N 9.00. Calc.
Zn4L2(SO3CF3)8. As described for Pb4L1(ClO4)8 but with for C54H46N16O28F24S8Cu4·8H2O: C 26.18; H 2.52; N 9.04.
Zn(SO3CF3)2 (279 mg, 0.768 mmol) and L2 (54.8 mg, ESMS m/z Found: 909.3699. Calc. for C46H46N16O4Na+:
0.0619 mmol) in CH3CN (5.00 mL); orange solid (110 mg, 909.3781. Selected IR ν/cm−1: 3245w, 3118w (CH), 3064w (CH),
79%): Anal. Found: C 26.83; H 2.85; N 9.08. Calc. for 1719w (CvO), 1656w (CvC), 1628w, 1604w, 1577m, 1551s
C54H46N16O28Zn4S8F24·CH3CN·8H2O: C 26.63; H 2.59; N 9.43. (CvN), 1481m, 1416m, 1383w, 1282s (CO), 1221s (SO3CF3−),
1H NMR (500 MHz, CD3CN) δ/ppm: 8.52 (2H, s, H11), 8.47 1149s, 1057s, 1023s. UV-Vis λmax (ε)/nm (L mol−1 cm−1): 684
(2H, s, H19), 8.38 (1H, s, H5), 8.22 (2H, t, J = 7.8 Hz, H22), 7.91 (546). Crystals suitable for X-ray diffraction were grown by the
(2H, d, J = 7.6 Hz, H21), 7.84 (4H, d, J = 7.8 Hz, H8/H23), 7.76 slow diffusion of diethyl ether into a CH3CN solution of
(1H, t, J = 7.3 Hz, H10), 7.70 (2H, m, H9), 6.92 (2H, s, H14), Cu(SO3CF3)2·4H2O and L2 in a 4 : 1 metal to ligand ratio.
6.47 (2H, d, J = 17.4 Hz, H28a), 6.25 (2H, dd, J = 10.5, 17.3 Hz, These crystals gave the structure [Cu3L2(SO3CF3)3(CH3CN)2
H27), 5.99 (2H, d, J = 10.6 Hz, H28b), 5.50 (4H, s, H25), 3.84 (H2O)](SO3CF3)32CH3CN·H2O (4).
(6H, s, H12), 3.76 (6H, s, H18), 2.81 (6H, s, H17). 13C NMR
Ag2L12(SO3CF3)2. As described for Pb4L1(ClO4)8 but with
(500 MHz, CD3CN) δ/ppm: 169.2 (C16), 169.1 (C2), 168.0 (C26), AgSO3CF3 (11.7 mg, 0.0457 mmol) and L1 (31.0 mg,
159.8 (C13), 159.3 (C15), 158.8 (C4/6), 158.4 (C24), 147.6 (C20), 0.0398 mmol) in CH3CN (5.00 mL); yellow solid (30.6 mg):
144.0 (C22), 139.7 (C19), 136.2 (C7), 135.5 (C11), 134.4 (C28), Anal. Found:
C
45.39;
H
4.06;
N
20.41. Calc. for
1
133.4 (C10), 131.2 (C9), 130.0 (C8), 128.5 (C21), 128.5 (C27), C41H42N16O5F3SAg·1/5AgSO3CF3: C 45.52; H 3.89; N 20.61. H
128.0 (C23), 123.5 (C5), 88.4 (C14), 66.3 (C25), 36.0 (C12), 35.0 NMR (500 MHz, CD3CN) δ/ppm: 8.54 (2H, m, H8), 7.87 (2H, t,
(C18), 26.9 (C17). ESMS m/z Found: 909.3766. Calc. for J = 7.7 Hz, H22), 7.68 (1H, s, H5), 7.66 (3H, m, H9/10), 7.46
C46H46N16O4Na+: 909.3781. Selected IR ν/cm−1: 3248br, 1730w (2H, s, H19), 7.29 (2H, d, J = 7.7 Hz, H21), 7.22 (2H, d, J =
(CvO), 1659w (CvC), 1601m, 1579m, 1556s (CvN), 1481m, 7.8 Hz, H23), 6.97 (2H, s, H11), 6.83 (2H, s, H14), 3.79 (4H, d,
1410m, 1372m, 1282s, 1223s (SO3CF3−), 1160s, 1116s, 1052s, J = 5.5 Hz, H25), 3.36 (2H, t, J = 5.6 Hz, H26), 3.12 (6H, s, H18),
1024s.
2.93 (6H, s, H12), 2.19 (6H, s, H17). ESMS m/z Found:
Cu4L1(ClO4)8. As described for Pb4L1(ClO4)8 but with 1921.5064, 1141.1256, 885.2805. Calc. for (C40H42N16O2)2-
Cu(ClO4)2·6H2O (61.1 mg, 0.165 mmol) and L1 (31.8 mg, Ag2(SO3CF3)+: 1919.4975. Calc. for C40H42N16O2Ag2(SO3CF3)+:
0.0409 mmol) in CH3CN (10.0 mL); green solid (65.4 mg, 1141.1299. Calc. for C40H42N16O2Ag+: 885.2728. Selected IR
87%): Anal. Found: C 27.37; H 2.96; N 12.58. Calc. for ν/cm−1: 3387br (OH), 3066w (CH), 3015w (CH), 2916w (CH),
C40H42N16O34Cl8Cu4·2CH3CN·2H2O: C 27.15; H 2.69; N 12.95. 2872w (CH), 1707w, 1572m, 1541s (CvN), 1527s, 1475s,
ESMS m/z Found: 940.2481, 451.1048. Calc. for C40H42N16O2Cu- 1458m, 1426m, 1406s, 1388m, 1365s, 1312w, 1272m (CO),
(ClO4)+: 940.2478. Calc. for C40H40N16O2Cu2
:
451.1051. 1246s, 1235s, 1222s (SO3CF3−), 1153s, 1087m, 1041s, 1026s.
2+
Selected IR ν/cm−1: 3452br (OH), 3067w (CH), 2939w (CH), Crystals suitable for X-ray diffraction were grown by the slow
1627m, 1601m, 1556s (CvN), 1476m, 1432m, 1381m, 1289m, diffusion of diethyl ether into a CH3CN solution of AgSO3CF3
1152m, 1048s (ClO4−). UV-Vis λmax(ε)/nm(L mol−1 cm−1): 690 and L1 in a 1 : 1 metal to ligand ratio. These crystals gave the
(449).
Cu4L1(SO3CF3)8. As described for Pb4L1(ClO4)8 but with
structure [Ag2L12](SO3CF3)2·CH3CN·H2O (5).
Ag2L12(BF4)2. As described for Pb4L1(ClO4)8 but with
Cu(SO3CF3)2 (68.1 mg, 0.157 mmol) and L1 (30.4 mg, AgSO3CF3 (9.80 mg, 0.0505 mmol) and L1 (29.1 mg,
8214 | Dalton Trans., 2014, 43, 8205–8218
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0.0374 mmol) in CH3CN (10.0 mL); yellow solid (33.1 mg): precursor AB, ligand L1 and complexes 1–5 are available in the
Anal. Found: 45.42; 3.83; 20.94. Calc. for ESI† along with a description of how the disordered com-
C
H
N
C40H42N16O2BF4Ag·4/9AgBF4: C 45.32; H 3.99; N 21.14. 1H ponents of the complexes were treated. The X-ray diffraction
NMR (500 MHz, CD3NO2) δ/ppm: 8.52 (2H, m, H8), 7.98 (2H, t, data for AB, L1 and complexes 1–3 and 5 were collected on
J = 7.8 Hz, H22), 7.84 (1H, s, H5), 7.67 (3H, m, H9/10), 7.56 a Bruker APEX II CCD diffractometer, with graphite mono-
(2H, s, H19), 7.41 (2H, d, J = 7.6 Hz, H21), 7.34 (2H, d, J = chromated Mo-Kα (λ = 0.71073 Å) radiation. Intensities were
7.7 Hz, H23), 7.13 (2H, s, H11), 7.00 (2H, s, H14), 3.96 (4H, s, corrected for Lorentz polarisation effects34 and a multiscan
H25), 3.26 (6H, s, H18), 3.08 (6H, s, H12), 2.23 (6H, s, H17). absorption correction35 was applied. The X-ray diffraction data
ESMS m/z Found: 887.2741. Calc. for C40H42N16O2Ag+: for complex 4 were collected on an Agilent Supernova dual
885.2728. Selected IR ν/cm−1: 3505br (OH), 2915w (CH), 2852w radiation source XRD with an Atlas detector, and a mirror
(CH), 1589w, 1569m, 1541s (CvN), 1475m, 1458m, 1426m, monochromated Cu (λ = 1.5418 Å) radiation source. The struc-
1405m, 1369m, 1311m, 1277m (CO), 1234m, 1155m, 1086m, tures were solved by direct methods (SHELXS36 and SIR-9737)
1039s (BF4−).
and refined on F2 using all data by full-matrix least-squares
Ag2L22(SO3CF3)2. As described for Pb4L1(ClO4)8 but with procedures (SHELXL 9738). All calculations were performed
AgSO3CF3 (12.7 mg, 0.0496 mmol) and L2 (41.2 mg, using the WinGX interface.39 Detailed analyses of the extended
0.0465 mmol) in CH3CN (10.0 mL); yellow solid (34.6 mg): structure were carried out using PLATON40 and MERCURY41
Anal. Found:
C
43.50;
H
3.64;
N
17.00. Calc. for (Version 3.1.1).
C47H46N16O7F3SAg·2/3AgSO3CF3: C 43.53; H 3.53; N 17.04.
1H NMR (500 MHz, CD3CN) δ/ppm: 8.53 (2H, m, H8), 7.93 (2H,
t, J = 7.8 Hz, H22), 7.69 (1H, s, H5), 7.51 (2H, s, H19), 7.41 (2H,
d, J = 7.8 Hz, H21), 7.26 (2H, d, J = 7.8 Hz, H23), 6.99 (2H, s,
Conclusions
H11), 6.86 (2H, s, H14), 6.05 (2H, dd, J = 1.3, 17.9 Hz, H28a), Tetratopic pym–hyz strands containing terminal hydroxy-
5.78 (2H, dd, J = 10.4, 17.3 Hz, H27), 5.56 (2H, dd, J = 1.3, methyl (L1) and acryloyl (L2) arms were successfully syn-
10.4 Hz, H28b), 4.35 (2H, d, J = 14.0 Hz, H25a), 4.30 (2H, d, J = thesised and characterised. X-ray crystallography and NMR
14.0 Hz, H25b), 3.09 (6H, s, H18), 2.92 (6H, s, H12), 2.22 spectroscopy showed that the ligands were folded into 1 and
(6H, s, H17). ESMS (CH3CN) m/z Found: 993.3015. Calc. for 1/3 helical turns in a similar fashion to the unmodified tetrato-
C46H46N16O4Ag+: 993.2939. Selected IR ν/cm−1: 3033w (CH), pic pym–hyz strands reported in the literature. Their behaviour
2925w (CH), 1727m (CvO), 1633w (CvC), 1574m, 1540s in the presence of metal ions has been investigated to a far
(CvN), 1474m, 1456m, 1429m, 1401s, 1366s, 1253s (CO), more thorough degree than any previous tetratopic pym–hyz
1222s (SO3CF3−), 1149s, 1118s, 1090s, 1041s, 1026s.
strand, as their Pb(II), Zn(II), Cu(II), and Ag(I) complexes have
Ag2L22(BF4)2. As described for Pb4L1(ClO4)8 but with AgBF4 been studied. The addition of excess Pb(II), Zn(II) or Cu(II) ions
(9.31 mg, 0.0479 mmol) and L2 (41.6 mg, 0.0470 mmol) in resulted in the uncoiling of L1 and L2 to form linear M4LA8
CH3CN (10.0 mL); yellow solid (33.5 mg): Anal. Found: C 46.67; complexes, with an amplitude of extension comparable to that
H
3.98; N 18.99. Calc. for C46H46N16O4BF4Ag·1/2AgBF4: of an unmodified tetratopic pym–hyz strand. Grid formation
1
C 46.86; H 3.93; N 19.01. H NMR (500 MHz, CD3CN) δ/ppm: was prevented in a 2 : 1 metal to ligand ratio by the coordina-
8.52 (2H, m, H8), 7.93 (2H, t, J = 7.8 Hz, H22), 7.69 (1H, s, H5), tive nature of the hydroxymethyl arms and the bulk of the
7.66 (3H, m, H9/10), 7.51 (2H, s, H19), 7.41 (2H, d, J = 7.7 Hz, acryloyl arms. Instead, the Pb(II) ions bound preferentially to
H21), 7.26 (2H, d, J = 7.7 Hz, H23), 6.99 (2H, s, H11), 6.86 (2H, the terminal pym–hyz–py pockets over the inner pym–hyz–pym
s, H14), 6.05 (2H, dd, J = 1.3, 17.3 Hz, H28a), 5.78 (2H, dd, J = sites to form horse shoe shaped Pb2LA4 complexes. This pre-
10.4, 17.3 Hz, H27), 5.56 (2H, dd, J = 1.3, 10.4 Hz, H28b), 4.35 ferential binding was also evident in the NMR spectra of the
(2H, d, J = 14.0 Hz, H25a), 4.30 (2H, d, J = 13.9 Hz, H25b), 3.09 Pb4LA8 and Zn4LA8 complexes as the ions occupying the inner
(6H, s, H18), 2.92 (6H, s, H12), 2.22 (6H, s, H17). ESMS pym–hyz–pym sites appeared to have a higher lability than
(CH3CN) m/z Found: 993.2965. Calc. for C46H46N16O4Ag+: those in the terminal sites. Additionally, one of the Cu(II) ions
993.2939. Selected IR ν/cm−1: 3034w (CH), 2922w (CH), 1724m bound to the inner pym–hyz–pym pockets was lost from the
(CvO), 1633w (CvC), 1575m, 1539s (CvN), 1474m, 1455m, Cu4L2(SO3CF3)8 complex during crystallisation, resulting in
1402s, 1365s, 1278m (CO), 1260m, 1223m, 1153m, 1119m, the formation of a twisted Cu3L2(SO3CF3)6 complex. Ag(I) ions
1037s (BF4−).
would not bind to the pym N donors in any metal to ligand
ratio, resulting in the formation of Ag2L2A2 helicates.
X-ray diffraction studies
L1 and L2 represent the first pym–hyz strands which
The crystallography associated with L1 and complexes 1–5 had express a significant amplitude of extension and contain term-
a number of issues, including poor resolution data and inal functional groups which allow them to be incorporated
low data/parameter ratios. Often this arose from the isolation into larger polymer networks. The extensive investigation into
of small thin crystals. For more details please refer to the their coordinative behaviour shows that the added functional
annotated CIFs.
groups do not prevent their uncoiling upon the addition of
Crystallographic data are summarised in Table 1. Thermal an excess of metal ions; however, they do influence the
ellipsoid pictures and selected bond lengths and angles for structures formed in low metal to ligand ratios. These results
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Table 1 Crystallographic data
AB
L1
1
2
Formula
Formula weight
Crystal system
Space group
C
14H19H7O
C40H42N16O2
778.90
Tetragonal
I41/a
C44H58Cl8N20O44Pb4
2683.46
Triclinic
ˉ
P1
C110H105F48N39O53Pb8S16
5904.00
Triclinic
ˉ
P1
301.36
Monoclinic
P21/n
a/Å
b/Å
c/Å
α/°
11.7201(15)
8.1454(10)
15.683(3)
90
100.962(5)
90
33.8887(17)
33.8887
15.8396(10)
90
90
90
9.2296(10)
17.3147(18)
25.755(3)
102.491(4)
96.675(4)
104.479(4)
3860.3(7)
2
18.0882(18)
19.955(3)
26.553(3)
70.191(5)
87.643(5)
87.432(5)
9004.7(17)
2
β/°
γ/°
V/Å3
1469.8(4)
4
18 191.1(13)
16
Z
T/K
90(2)
0.093
90(2)
0.076
90(2)
9.087
90(2)
7.774
μ/mm−1
Reflections collected
9733
91 123
39 972
8364 (0.0620)
0.0564
0.1389
1.030
93 775
33 396 (0.0510)
0.0706
0.1804
0.104
Unique reflections (Rint
R1 indices [I > 2σ(I)]
wR2 (all data)
)
2673 (0.0383)
0.0597
0.1563
1.034
5861 (0.0443)
0.0665
0.1684
1.156
Goodness-of-fit
3
4
5
Formula
Formula weight
Crystal system
Space group
C96H112Cl8N38O41Pb4
C60H62Cu3F18N20O24S6
2172.28
Triclinic
ˉ
P1
C84H89Ag2F6N33O11S2
2130.77
Triclinic
ˉ
P1
3566.64
Monoclinic
C2/c
a/Å
b/Å
c/Å
α/°
29.752(3)
10.5359(9)
44.383(4)
90
109.239(3)
90
11.93796(15)
18.6842(2)
21.6335(2)
113.9013(11)
92.2282(9)
105.8198(11)
4182.87(9)
2
15.957(3)
16.872(3)
17.655(3)
90.879(8)
104.340(8)
99.074(8)
4540.1(14)
2
β/°
γ/°
V/Å3
13 135(4)
4
Z
T/K
90(2)
5.368
100(2)
3.413
90(2)
0.569
μ/mm−1
Reflections collected
Unique reflections (Rint
R1 indices [I > 2σ(I)]
wR2 (all data)
Goodness-of-fit
43 553
96 122
14 909 (0.0451)
0.0838
0.2487
1.042
22 229
7056 (0.0557)
0.0695
0.01691
1.065
)
12 429 (0.0559)
0.0698
0.1544
0.0698
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