Enhanced anion binding from unusual coordination modes of bis(thiourea) ligands in platinum group metal complexes

Article abstract of DOI:10.1002/chem.201001354

Treatment of a range of bis-(thiourea) ligands with inert organometallic transition-metal ions gives a number of novel complexes that exhibit unusual ligand binding modes and significantly enhanced anion binding ability. The ruthenium(II) complex [Ru(η⁶-p-cymene)(κS,S′,N-L ³-H)] ⁺ (2b) possesses juxtaposed four- and seven-membered chelate rings and binds anions as both 1:1 and 2:1 host guest complexes. The pyridyl bis(thiourea) complex [Ru(η⁶-p-cymeme)(κS,S′, N_py-L⁴)]²⁺ (4) binds anions in both 1:1 and 1:2 species, whereas the free ligand is ineffective because of intramolecular NH...N hydrogen bonding. Novel palladium(II) complexes with nine- and ten-membered chelate rings are also reported.

Full text of DOI:10.1002/chem.201001354

DOI: 10.1002/chem.201001354
Enhanced Anion Binding from Unusual Coordination Modes of
Bis(thiourea) Ligands in Platinum Group Metal Complexes
ACHTUNGTRENNUNG
M. Laura Soriano,[a] Joseph T. Lenthall,[a] Kirsty M. Anderson,[a] Stephen J. Smith,[b] and
Jonathan W. Steed*[a]
Abstract: Treatment of a range of bis-
(thiourea) ligands with inert organome-
tallic transition-metal ions gives
number of novel complexes that exhib-
it unusual ligand binding modes and
significantly enhanced anion binding
ability. The ruthenium(II) complex
[Ru(h6-p-cymene)(kS,S’,N-L3ÀH)]+
(2b) possesses juxtaposed four- and
seven-membered chelate rings and
binds anions as both 1:1 and 2:1 host
guest complexes. The pyridyl bis-
me)(kS,S’,Npy-L4)]2+ (4) binds anions in
both 1:1 and 1:2 species, whereas the
free ligand is ineffective because of in-
tramolecular NH···N hydrogen bond-
ing. Novel palladium(II) complexes
with nine- and ten-membered chelate
rings are also reported.
ACHTUNGTRENNUNG
a
(thiourea) complex [Ru(h6-p-cyme-
ACHTUNGTRENNUNG
Keywords: anion binding · chelates ·
supramolecular chemistry · transi-
tion metals · thiourea
Introduction
DMSO[22–26] and have been incorporated into monolayers to
mimic ion-channel sensing of hydrophilic anions.[27]
The design of host molecules capable of selective recogni-
tion of anionic species is still an area of intense current aca-
demic and industrial interest,[1–6] particularly in the detection
and extraction of environmentally relevant anionic species
such as nitrate, phosphates, pertechnetate, perchlorate, arse-
nate and chromate.[7–11] We are particularly concerned with
the understanding and use of structure, conformational as-
pects and supramolecular interactions to modulate the abili-
ty of the receptors to bind different anions. A particularly
important class of anion receptors are those based on thio-
urea[2,12–21] functionalities because of their ability to form
strong hydrogen-bond complexes with anions, and their syn-
thetic accessibility. Simple bis(thioureas) have been shown
to bind glutarate, dihydrogenphosphate and acetate in
They also act as phase-transfer agents from water to nitro-
À
benzene for hydrophilic anions, such as ClÀ, AcOÀ, H2PO4 ,
2À
2À [28]
HPO4 and SO4
.
A fluorescent anion sensor based on a
pyrene electron acceptor linked to a thiourea donor and a
colorimetric sensor based on p-nitrophenylthiourea have
been prepared.[29,30] Gunnlaugsson and co-workers have de-
veloped similar chemosensors for anions by using anthra-
cene-based fluorescent sensors.[20,31,32] Other examples of re-
cently synthesised thiourea sensors include hosts with the
thiourea group linked to fluorescent sensor moieties by a
rigid hydrazine spacer selective for acetate,[33–36] Hosts based
on coumarin sensors that act as both fluorescent and colori-
metric sensors[37] and compounds that utilise cooperativity
between the thiourea group and an amine group adjacent to
a naphthalimide sensor are also known.[38,39] Sensors using
[a] Dr. M. L. Soriano, Dr. J. T. Lenthall, Dr. K. M. Anderson,
Prof. J. W. Steed
Department of Chemistry, Durham University
South Road, Durham
DH1 3LE (UK)
Fax : (+44)191-384-4737
E-mail: jon.steed@durham.ac.uk
[b] Dr. S. J. Smith
BP Chemicals Ltd., Hull Research and Technology Centre
Saltend, Hull
HU12 8D (UK)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.201001354.
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FULL PAPER
bis
G
attributed to the reduced nucleophilicity of the pyridyl dia-
mine. The monothiourea 1-pyridin-2-yl-3-p-tolyl thiourea
(L5) was also synthesised in good yield by treating 2-amino-
pyridine with p-tolyl isothiocyanate.[75] Ligands L1 and L2
are only soluble in DMSO. To increase the solubility, treat-
ment of 1,2-phenylenediamine with bulkier isothiocyanates,
such as iPr-NCS or tBu-NCS, was undertaken in a variety of
solvents under both thermal and microwave conditions, but
several problems occurred: no reaction, monosubstitution of
the precursor o-phenylene diamine or production of the cy-
clised product benzimidazoline-2-thione[76,77] (see the Sup-
porting Information for a full discussion). To disfavour inter-
nal cyclisation and encourage reaction of the singly func-
tionalised ligands with a further equivalent of isothiocya-
nate, treatment of 1,2-phenylenediamine and the isothiocya-
nates in high concentrations was attempted. A minimum
amount of hot ethanol was added to the mixture to dissolve
the phenylenediamine. The mixture was sonicated and left
overnight. From this concentrated solution, the isopropyl de-
rivative 1-isopropyl-3-[2-(3-isopropylthioureido)phenylene]-
thiourea (L3) can be isolated in good yield and highly crys-
talline form. This reaction indicates that the use of concen-
trated solutions to favour the intermolecular reaction of the
intramolecular cyclisation is a key factor in the synthesis.
However, using this technique with tBuNCS gave only the
singly functionalised compound.
nol, biaryls and anthraquinone.[40–42] A range of tripodal tri-
sureas that bind dihydrogenphosphate and acetate anions
have also been reported.[43] Thioureas in particular are rela-
tively acidic, which leads to strong hydrogen-bonding inter-
actions (although the stabilisation of the conjugate base can
lead to deprotonation by basic anions[44–47]). The thiourea
sulfur atom is more exposed than the urea carbonyl oxygen
atom, however, and thus urea self-association can compete
with hydrogen bonding to a target anion guest, in some
cases leading to species such as gels.[48,49] A particularly at-
tractive class of thiourea-based anion receptors are bis-
(thioureas), in which the urea functionalities are linked by a
spacer and arranged in such a way that all four sets of NH
hydrogen bond donors converge on an anion binding site.
Such complexes have been reported to act as effective
anion-binding receptors.[13,15,17,19,46,50,51] However, problems
can arise in these neutral acyclic systems due to lack of pre-
organisation and solvent competition. Although cyclic bis-
ACHTUNGTRENNUNG
complexes with a range of platinum group metals. The pres-
ence of a metal centre can exert a significant preorganising
effect and also modulate the electronic properties of the
ligand. As a result, metal-based anion receptors are increas-
ingly topical.[1,6,7,54–74] We also report the extensive, varied
and novel coordination chemistry of a range of platinum
Ruthenium complexes: “Piano-stool” complexes of type
group metal bis
[RuACTHUNGETRNNUG
(h6-arene)L*] (L*=mono- or bidentate pyridine or bii-
midazole derivatives) have proved to be successful anion
hosts in a number of recently reported systems.[70,78–80] To in-
vestigate the coordination chemistry of thiourea ligands L1–
L5, particularly with a view to preorganising the ligand and
tying up the sulfur atoms that can compete with anions as
hydrogen-bond acceptors, the reaction of the convenient p-
Results and Discussion
Ligand synthesis: The bis
ACHTUNGTRENNUNG
methylthioureido)ethyl]thiourea
methylthioureido)phenylene]thiourea (L2) and 1-methyl-3-
[6-(3-methylthioureido)pyridin-2-yl]thiourea (L4) were easily
synthesised by treating methyl isothiocyanate with ethylene-
diamine, 1,2-phenylenediamine and 2,6-diaminopyridine, re-
spectively. The ligands were isolated in pure form as a pre-
cipitate after concentration of the original reaction solutions.
In all reactions, an excess (ꢀ10%) of methyl isothiocyanate
was used, and this excess was washed away from the product
with diethyl ether. A low yield for pyridyl ligand L4 may be
ACTHNGUTERNNUG
cymene complex [{Ru(h6-C6H4MeCH(Me)2)Cl(m-Cl)}2][81]
with two equivalents of ligand L3 was undertaken in CHCl3
at room temperature for 3 h. This reaction resulted in a ma-
terial that was found to be a 1:1 complex of empirical for-
mula Ru(h6-C6H4MeCH(Me)2)Cl2(L3) (1), which exhibits a
1
broad H NMR spectrum with many resonances, suggesting
a number of equilibrating species (vide infra). This crude
product was dissolved in distilled water and then extracted
into CHCl3 to give
a
compound of formula [Ru(h6-
C6H4MeCH(Me)2)(kS,S’,N-L3ÀH)]Cl (2b), which is a single
complex that involves a deprotonated form of L3. It also
proved possible to exchange the chloride counterion for
À
BF4 by treating 2b with AgBF4 in CH2Cl2 to give [Ru(h6-
C6H4MeCH(Me)2)(kS,S’,N-L3ÀH)]BF4 (2b’). The 1H NMR
spectrum of 2b shows that the thiourea ligand has become
unsymmetrical and exhibits only three NH signals. The
AA’BB’ pattern for the p-cymene resonances and the diaste-
reotopic isopropyl methyl groups on both ligands are mag-
netically inequivalent, with a spectrum characteristic of a
stereogenic metal centre.[79,82,83] For example, the isopropyl
CH3 resonances of L3 occur at d=1.03, 1.04, 1.13 and
1.14 ppm, showing that not only are both isopropyl arms
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J. W. Steed et al.
within the ligand unsymmetrical but that each CH3 within
each arm is inequivalent. COSY NMR spectroscopic data
indicate that deprotonation occurs on one of the NH pro-
tons adjacent to the aryl ring. There are a total of 24 reso-
nances in the {1H}13C NMR spectrum, which again confirms
the asymmetrical nature of the molecule, in particular the
two resonances for the C=S carbon atoms at d=178.62 and
180.20 ppm. Given that this species is obtained from the
crude material in a yield of 75%, it is clear that the water is
not simply extracting one complex from the initial crude
mixture but inducing the deprotonation and coordination of
a urea nitrogen atom and driving the mixture over to an
ionic product.
Compound 2b exhibits a single peak in the ESI-MS, with
a 100% relative abundance at m/z 545.1 with a ruthenium
isotope envelope, which may be assigned to the proposed
monocationic
C6H4MeCH(Me)2ACHTUNGTRENNUNG
monomeric
compound,
[
102Ru(h6-
(L3ÀH)]+. The IR spectrum of the uncoor-
dinated ligand exhibits strong bands at n˜ =3315 and
3256 cmÀ1 assigned as N H stretching modes. In the com-
À
plex, these bands are replaced by a strong band at n˜ =
3216 cmÀ1 and a weaker band at n˜ =3130 cmÀ1, which shows
a significant change in the NH environment. This is also re-
flected in a smaller change in absorbance bands assignable
to the NH bending from ligand bands at n˜ =1598 and
1563 cmÀ1 to n˜ =1591 and 1561 cmÀ1 in the complex. A
strong absorbance band in the C=S stretch region shifts
from n˜ =1265 cmÀ1 in the ligand to n˜ =1167 cmÀ1 in the com-
plex.
Figure 1. a) The X-ray crystal structure of 2b showing the hydrogen
bonding to the chloride anion. b) The hydrogen-bonded dimer observed
in the solid state. Thermal ellipsoids are drawn at the 50% probability
level.
The formulation of 2b was confirmed by an X-ray crystal
structure determination (Figure 1a) that proved to be fully
consistent with the NMR spectroscopic and analytical data.
The ligand adopts a terdentate binding mode with both
sulfur atoms and the deprotonated nitrogen atom binding to
the stereogenic metal centre to give adjacent four- and
seven-membered chelate rings. This geometry appears to be
unprecedented in the CSD.[84,85] The neutral thiourea moiety
adopts a syn conformation in which both hydrogen atoms
form an R21(6) motif[86,87] with the uncoordinated chloride
counterion. The remaining NH group of N(1) forms a hy-
drogen bond to the opposite face of the chloride anion and
as a result the complex in the solid state forms a centrosym-
metric hydrogen-bonded dimer linked by interactions to the
chloride anions (Figure 1b). A bidentate, N,S-coordination
mode has been seen in a number of deprotonated mono-
thiourea derivatives of ruthenium,[88,89] platinum(II),[90,91]
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L1ÀH)]Cl·H2O (3). Inter-
estingly, the 1H NMR spectrum of 3 is broad in nature,
unlike the spectra obtained for the phenylene spacer com-
pounds of 2, and each of the NH resonances is split into two
signals of different intensity (Figure 2). This data suggests
that the molecule exists in two isomeric conformations in so-
ACTHNUTRGNEUNG
cadmium,[92] zinc,[93] gold(III)[94] and gold(I).[95] The N,S-thio-
Figure 2. Partial 1H NMR spectrum of 3 showing the two sets of three
NH resonances (peak at d=7.24 ppm is residual CHCl3).
ureido chelate binding mode is also observed for complexes
with rhenium(V) in a thiol-amide-thiourea ligand,[96] and it
is found in both coordinating thioureas for an analogous bis-
A
lution. This conformational isomerism may be linked to the
flexibility of the ethylene spacer in L1 in comparison to the
more rigid L2 and L3. The greatest difference in the chemical
shift for the conformations is observed for the NH proton at
d=7.41 ppm for the major conformer and d=8.14 ppm for
the minor conformer. This may be attributable to two differ-
ent hydrogen-bonding environments, in particular hydrogen
of acetate deprotonates three of the four NH protons and
leads to coordination of one monoanionic and one dianionic
species within the same molecule.
The reactions of [{Ru(h6-C6H4MeCH(Me)2)Cl
ACTHNUTRGNEG(NU m-Cl)}2]
with related ligands L1 and L2 gave similar products of for-
mula [Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L2ÀH)]Cl (2a) and
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Anion Binding
FULL PAPER
bonding to a chloride counterion that suggests a greater in-
teraction with the chloride anion for the minor conformer.
Compounds 2a and 3 were also characterised by X-ray
crystallography and both structures give additional insight
into the possible conformational isomerism observed for 3
in solution (see Figure 3). Compound 2a crystallises as a
one possible explanation for the isomerism observed in 3.
The co-crystallisation of both conformers in a single crystal
of 2a might result from the fact that crystals were obtained
by rapid cooling of a hot ethyl acetate solution as opposed
to slow crystallisation at room temperature over a number
of days in the case of 2b and 3.
Compound 3 was characterised by X-ray crystallography
as a monohydrate. The structure is broadly similar to those
of compounds 2 but interestingly reveals a second kind of
À
isomerism that involves rotation about the C(5) N(4) bond
(the bond from the carbon atom of the neutral thiourea to
the terminal NHMe group). The thiourea thus adopts an
anti conformation, rather than syn as observed for the other
two compounds (see Figure 4a). This change has a funda-
mental effect on the hydrogen bonding to the chloride coun-
ter anions. The common R12(6) motif observed in compounds
2 is replaced by hydrogen bonding to the water molecule,
which in turn interacts with the choride counterion. The
chloride anion is bound on the other side by the NH group
of the deprotonated thiourea N(1)H. The remaining NH
group forms a hydrogen bond to water and thus the struc-
ture comprises hydrogen-bonded dimers linked to a a ClÀ -
2
AHCTUNGTREN(GNNU H2O)2 unit bound to each cationic complex through only a
single anion (Figure 4b).
Both sulfur inversion isomerism and syn/anti isomerism of
the thiourea moiety have precedent for occurring on a time
scale comparable with the NMR spectroscopic time scale,
however, the latter process seems to be more consistent
with the significant differences in chemical shift and thus hy-
drogen bonding to the anion observed in the two solution
conformers in 3.
Figure 3. The X-ray crystal structures of 2a showing the conformational
isomerism at the sulfur atom. a) Molecule 1 based on Ru(1); b) mole-
cule 3 based on Ru(3). The molecule based on Ru(2) is an enantiomer of
molecule 1. Thermal ellipsoids are drawn at the 50% probability level.
Because compounds 2 and 3 both involve thiourea depro-
tonation to provide three donor atoms for the ruthenium(II)
centre, the treatment of [{Ru(h6-C6H4MeCH(Me)2)Cl
ACHTUNGTRENNUNG(m-
Cl)}2] with terdentate ligand L4 was undertaken. This reac-
tion gave a single product with a symmetric set of resonan-
1
ces in the H NMR spectrum that can be assigned to the ter-
conformational isomorph[98] in a remarkable structure com-
prised of three crystallographically independent molecules
(Z’=3[99]). Molecules based on Ru(1) and Ru(2) comprise
an enantiomeric pair linked by hydrogen bonding to their
chloride counterions. Both the conformation and mode of
interaction with chloride are very similar to the structure of
2b, and the bond lengths and angles are not significantly dif-
ferent from the isopropyl analogue. The molecule based on
Ru(3) also forms an anion-bridged hydrogen-bonded dimer
with a crystallographic inversion symmetry equivalent of
itself, however the conformation of the ligand is different
because of an inversion of configuration at the sulfur atom
of neutral thiourea functionality S(6). This factor results in
the thiourea group being approximately coplanar with the
p-cymene ring rather than almost perpendicular to it as in
the other isomer. Metal complexes of sulfur ligands can dis-
play significant conformational rigidity and the inversion
barrier at sulfur is sometimes sufficiently high enough to dis-
tinguish S-inversion conformers in solution by using NMR
spectroscopy.[100,101] Although this is not the case for 2a, it is
dentate S,S’,Npy chelate [Ru(h6-C6H4MeCH(Me)2)(kS,S’,Npy-
L4)]Cl2 (4), which was fully characterised. The displacement
of all of the chloride from the ruthenium(II) centre without
treatment with silver(I) is unusual and may be related to the
terdentate nature of the ligand and the involvement of the
chloride ligands in hydrogen bonding in the product. Addi-
tion of water to the mixture, however, gives a mixture of 4
1
and a second species with an unsymmetrical H NMR spec-
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J. W. Steed et al.
even without treatment with
water. The product was identi-
fied
[Ru(h6-
C6H4MeCH(Me)2)ClAHCTUNGTENRN(UNG kS,N-
as
L5)]Cl·2H2O (5), in which the
pyridyl thiourea acts as a neu-
tral, bidentate chelate without
deprotonation. The large down-
field shift in one of the NH res-
onances from d=8.84 ppm in
the free ligand to d=11.95 ppm
in 5 suggests significant interac-
tion with the chloride counter-
ion.
Reactions with platinum and
palladium complexes: Reaction
of bis(thioureido) ligands with
[Pd
(MeCN)2Cl2]
and
[Pt-
AHCTUNGTERG(NNUN MeCN)2Cl2] formed insoluble
complexes of general formula
MLxCl2 (x=1.5 and 2), even if
a 1:1 M/L stoichiometry was
used. ESI-MS shows periodic
peaks up to high molecular
weights (m/z >2000). It is
likely that coordination oligo-
mers or polymers are being
formed. Therefore, diphenyl-
phosphinoethane (DPPE) was
used to block coordination sites
and allow the formation of dis-
crete species. The general
Figure 4. The X-ray crystal structure of 3·H2O. a) The anti conformation of the urea moiety based on C(5);
thermal ellipsoids are drawn at the 50% probability level. b) The extended crystal packing showing counterion
and water interactions.
trum that probably results from thiourea deprotonation. It is
possible that in this species a bidentate deprotonated thiour-
ea moiety replaces the pyridyl unit. This material was not
isolated, but evidence for the lability of the pyridyl moiety
comes from the mass spectrum of 4 in acetonitrile solution,
which reveals a peak at m/z 265 that can be assigned to the
acetonitrile adduct [Ru(h6-C6H4MeCH(Me)2)
ACTHNUTRGENN(GU MeCN)CAHTUNGTRENN(UGN kS,S’-
L4)]2+. The chloride anions in 4 could be exchanged for
À
BF4 by treating 4 with AgBF4 in CH2Cl2 followed by re-
moval of precipitated AgCl to give the tetrafluoroborate
salt
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,Npy-L4)]
G
(4’).
Compound 4 was characterised by X-ray crystallography as
the dichloromethane solvate and exhibits the expected sym-
metrical structure. The urea NH groups face away from the
metal centre in a syn arrangement to form R12(6) hydrogen
Figure 5. The X-ray crystal structure of 4·2CH2Cl2. Thermal ellipsoids are
drawn at the 30% probability level.
À
bonding motifs with the chloride anions (Figure 5). The Ru
N(3) bond length of 2.120(2) ꢁ is normal and does not sug-
gest any particular strain in the molecule.
Treatment of [{Ru(h6-C6H4MeCH(Me)2)Cl
(m-Cl)}2] with
method for the reaction proceeds in a similar fashion to
work by Burrows et al.[102] by coordinating DPPE to palladi-
um or platinum first, followed by introduction of the chelat-
mono-thiourea L5 was undertaken for comparison. The
starting materials were heated at reflux under N2 for 3 h in
chloroform to give a single product that again exhibited a
1H NMR spectrum indicative of a stereogenic metal centre,
ing ligand. In this way, complexes of formulae [M
ACHTUNGTRENNUNG
A
E
U
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Anion Binding
FULL PAPER
L1)]Cl (kS,S’-L4)]Cl
ACHTUNGTRENNUNG(PF6) (7) and [PdACHUTGTNRENNUG(dppe)ACHNUTGERTNUNGN CATHNUGTRENUN(GN PF6) (8) were
synthesised and characterised. Complexes 6–8 all showed
1H, 13C{1H} (solubility allowing) and 31P NMR spectra con-
sistent with a symmetrical bidentate binding mode of the
neutral bisACHTUNGTRENNUNG(thiourea) ligands to give either nine-membered
or, in the case of 8, ten-membered chelate rings. No evi-
dence for binding of the pyridyl nitrogen atom of L4 in 8
was observed, presumably because only two sites on the pal-
ladium(II) centre are available for coordination. Nine-mem-
bered chelate rings are rare, with only one other disulfur ex-
ample, nitrosyl hydrotris(3,5-dimethylpyrazolyl)borate-N-
ethylthio(mercaptopropionamide) molybdenum, found in
the CSD.[103] Ten-membered rings are also highly unusual,
with the only examples involving partially coordinated
sulfur macrocycles on osmium clusters.[104]
(dppe)(L3)]Cl
Figure 6. a) The molecular structure of [PdACHTUGNTERNNNUG AHCUTNRTGE(GNUNN PF6)·ACHTUNGTRENNUNG(CH3)2CO,
displaying the ligand aryl···Pd interaction and hydrogen bonding to the
chloride counterion and acetone solvent molecule. b) Hydrogen bonding
to the chloride counterion to give a dimeric structure.
product was stirred with an excess of NH4PF6 to force com-
plete metathesis. However, this tendency to retain at least
one chloride anion proved to be a general feature of these
types of compound and 7 and 8 were characterised as mixed
salts.
Crystals of the mixed-anion acetone solvate [Pd
ACHTUNGTRNE(NUNG dppe)-
G
A
ACHTUNGTRENNUNG
ration of a solution of 6 in acetone/diethyl ether. The molec-
ular structure confirms the S,S’ binding mode and formation
of the nine-membered chelate ring (Figure 6a). The struc-
ture adopts a conformation in which the axial region on the
square-planar palladium(II) centre is occupied by the aro-
À
Reactions with iridium complexes: Although a complex
mixture of products was obtained from the direct treatment
of L3 with [{Ru(h6-C6H4MeCH(Me)2)Cl
ACHTUNGTRENNUNG
matic ring of the benzo-spacer bisACTHUNTRGEN(UNG thiourea) ligand (Ccentroid
À
À
Pd=3.42 ꢁ; closest C Pd contact 3.14 ꢁ; lower aryl C=C
Pd distance 3.07 ꢁ). The thioureido group of one ligand arm
is disordered over two sites; one site forms a hydrogen bond
to the acetone solvent of crystallisation molecule (N(4) and
N(3)), whereas in the other conformation both N(4’) and
N(3’) form hydrogen bonds to the chloride counterion to
A
ACHTUNGTRENNUNG
AHCTUNGTRENNUNG
product [{Cp*IrCl(m-S,S’-L3)}2](Cl)2 (9), which was isolated
as the acetone solvate and characterised by single crystal X-
ray diffraction. The structure contrasts significantly to com-
pounds 2–8 in that it is a 2+2 metallomacrocycle in which
two neutral L3 ligands are bridged by their sulfur atoms be-
give
a chloride-bridged, hydrogen-bonded dimer (Fig-
ure 6b). The bond lengths to the metal are within expected
ranges and the angles around the square-planar palladium
centre deviate only slightly from 908. The crystals obtained
arise from incomplete metathesis of chloride counterions
with hexafluorophosphate anions and thus the crystals con-
tain one anion of each type. For analytical purposes, the
tween two iridiumACTHNGUTERNNU(G III) centres. The structure has the same
1:1 metal/ligand ratio as adduct 1, however, and it is possible
that a similar macrocyclic species is part of the equilibrating
mixture observed in the ruthenium complex. The coordina-
tion geometry about the iridium ions is of the usual piano-
stool variety with the “legs” comprised of two thiourea
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J. W. Steed et al.
Table 1. Anion binding constants for ligand L3 and complexes 2b’ and
4’.[a]
sulfur atoms from two different L3 ligands and a terminal
chloride ligand as shown in Figure 7. The thiourea groups
adopt an anti conformation with one NH group from each
Anion
L3
2b’
4’
logb11
logb11
logb21
logb11
logb12/21
3.52(8)[b]
1.29(2)[c]
3.52(9)[b]
3.01(3)[b]
2.30(2)[b]
2.28(3)[b]
1.81(1)[b]
0.78(1)[b]
>5[b]
>5[b]
2.82(5)[c]
dep
4.10(3)[d]
3.02(3)[c]
dep[d]
7.05(6)[d,e]
5.20(9)[c,f]
dep[d]
ClÀ
1.50(6)[c]
dep
AcOÀ
BrÀ
NO3
>5[b]
>5[b]
3.92(2)[d]
3.96(2)[d]
ppt[d]
6.10(6)[d,e]
6.22(5)[d,e]
ppt[d]
À
4.34(7)
5.66(7)
À
HSO4
>5[b]
>5[b]
IÀ
3.59(1)[b]
<1[b]
5.91(4)[b]
–
3.29(5)[d]
–
5.79(12)[d,e]
–
À
ReO4
[a] Abbreviations: dep=deprotonation, ppt=precipitation. [b] Acetone.
[c] DMSO. [d] Chloroform. [e] Logb12 (two anions per host) also includes
host dimerisation constantlog b20 =2.07. [f] Logb21 (anion binding by host
dimer).
(Figure 8). For the metal complexes, these changes were
mirrored by a corresponding upfield shift in the chemical
À
shift of the BF4 ions in the 19F NMR spectra due to the dis-
À
placement of the weakly bound BF4 ion by the more
strongly bound guest anions (Figure 9).
For free L3, titration experiments were undertaken in
[D6]acetone. The free ligand shows the highest binding con-
stants for chloride and acetate, with affinity decreasing ac-
cording to the negative charge density of the anion in an
anti-Hofmeister fashion (Table 1). The small variation in the
chemical shift observed for perrhenate indicates very weak
binding. A Job plot with ClÀ confirmed that binding occurs
through a 1:1 complex and the binding mode was confirmed
by means of a single-crystal X-ray structure of the bromide
complex of L3 (Figure 10). The structure shows the anion
bound within a receptor cleft formed by the two syn thiour-
ea units to form four NH···BrÀ hydrogen bonds in a similar
Figure 7. The X-ray crystal structure of [{Cp*IrCl(m-S,S’-L3)}2](Cl)2 (9),
showing the included acetone molecule and hydrogen bonding to both
coordinated and uncoordinated chloride. The intramolecular hydrogen
bonding appears to be responsible for the cisoid conformation of the
chloride ligands on the two metal centres.
thiourea forming a hydrogen bond to a chloride counterion
whereas the other forms an unusual intramolecular hydro-
gen bond to the coordinated chloride ligand. The geometry
of L3 means that these hydrogen bonds necessarily occur on
one face of the ligand and thus the two chloride ligands on
the two IrIII ions are mutually eclipsed in a cisoid geometry
rather than adopting a transoid disposition of the type seen
in the halide-bridged starting materials, for example.[106] The
two phenylene linkers of the two L3 ligands define the walls
of a molecular cavity that is occupied by either an acetone
molecule or a disordered acetone/THF mixture (two inde-
pendent molecules). Metathesis of 9 with AgBF4 gave the
analogous tetrafluoroborate salt, [{Cp*IrCl(m-S,S’-L3)}2]-
fashion to carboxylate binding by the related bisACTHNUTRGENUG(N urea) ana-
logue.[109,110] Anion binding by the diphenyl analogue of L3
has been previously reported to be weak in the highly com-
petitive solvent DMSO/water because of steric interactions
between the sulfur atoms and the phenylene hydrogen
atoms. The structure of L3·BrÀ shows that the sulfur atoms
do indeed adopt an out-of-plane conformation but this does
not entirely prevent effective anion binding in the present
case, albeit in less competitive media.[109]
ACHTUNGTRENNUNG(BF4)2 (9’), which still retains coordinated chloride ligands.
The anion binding of L4 was examined in acetone and
DMSO. Anion binding was extremely weak in both solvents,
with only small chemical shift changes observed. This inef-
fective complexation is attributed to the formation of intra-
molecular hydrogen bonding from the thiourea NH groups
to the pyridyl nitrogen atom. This hypothesis was confirmed
by the X-ray crystal structure of the NBu4+ClÀ complex of
L4, which shows chloride binding to only one thiourea
group, with the other forming an intramolecular NH···Npy in-
teraction with a bifurcated component (Figure 10b).
In comparison with the free ligand, anion binding by both
2b’ and 4’ proved to be extremely strong, with the ClÀ affini-
ty of 2b in acetone being too high to measure accurately by
NMR spectroscopic methods (acetone was used for compar-
ison with the free ligand). This added affinity is interpreted
Anion binding by ruthenium complexes: Due to solubility
constraints, we chose to study the anion-binding behaviour
of ligands L3 and L4 in comparison with their ruthenium de-
rivates as BF4 salts (i.e., 2b’ and 4’). A variety of anions
+
were introduced as NBu4 salts. Binding constants were
1
measured by using H NMR spectroscopic titration and, in
À
the case of the metal BF4 complexes, 19F NMR spectrosco-
py at room temperature. Binding constants were calculated
by using non-linear least-squares regression with the
HypNMR2006 software[107,108] and are summarised in
Table 1.
In all cases, the resonances assigned to the NH groups
shifted downfield upon titration with anions due to the for-
mation of hydrogen-bonded host–anion complexes
10824
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ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 10818 – 10831

Anion Binding
FULL PAPER
À
Figure 9. The change in chemical shift for BF4 anion by 19F NMR spec-
troscopy (a) of 2bꢀ in [D6]acetone and (b) 4ꢀ in chloroform upon addition
À
À
À
À
À
À
~
&
&
^
*
*
of different anions ( : AcO , : Cl , : Br , : I , : NO3
^
,
: HSO4 ,
: ReO4À).
Figure 8. The change in chemical shift of the NH resonance adjacent to
the phenylene ring for a) L3, b) ruthenium complex 2b’ in [D6]acetone
and c) both NH resonances in complex 4’ in chloroform upon addition of
À
À
À
À
À
À
~
&
&
^
*
*
different anions ( : AcO , : Cl , : Br , : I , : NO3
^
,
: HSO4 ,
: ReO4À).
as arising from the high degree of preorganisation afforded
by the metal centre, the polarising effect on the NH bonds
from coordination to the dicationic metal ion and the posi-
tive charge itself. This enhancement occurs despite the fact
that only three NH groups are available in 2b as opposed to
four in L3. A Job plot of ClÀ complexation by 2b’ in acetone
shows a peak at around 0.6 host/guest ratio, suggesting the
coexistence of both 1:1 and 2:1 host guest complexes (Fig-
+
Figure 10. The X-ray crystal structures of the NBu4 bromide complex of
L3 (top) and the NBu4 chloride complex of L4 (bottom).
+
ure 11a). This stoichiometry fits the titration data well in
cases where binding constants were low enough to be re-
fined. It is likely that at low chloride concentration two
monocationic hosts fit around the guest anion because a
Chem. Eur. J. 2010, 16, 10818 – 10831
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
10825

J. W. Steed et al.
of the complexes of 4’ in chloroform (Figure 9b). The
chloroform data for 4’ shows a much larger change in chemi-
À
cal shift on going from bound to free BF4 as compared
with the data obtained in acetone for 2b’, probably as a
À
result of more significat ion pairing of even the labile BF4
À
in chloroform. No chemical shift change for the BF4 anion
was observed in DMSO, which confirms that tetrafluorobo-
rate is not bound by these compounds in such a competitive
solvent.
Conclusion
This work has revealed a number of unusual chelating coor-
dination modes of bisACTHNUTRGNE(NUG thiourea) ligands, including the for-
mation of complexes with seven-, nine- and ten-membered
chelate rings. Compounds of type 2 exhibit interesting syn/
anti isomerism that is slow on the NMR spectroscopic time-
scale in some complexes and impacts on their anion-binding
behaviour. Generally, however, metal coordination enhances
the preorganisation and hydrogen-bond acidity of bis-
Figure 11. Job plots for ClÀ binding by a) 2b’ in [D6]acetone and b) 4’ in
AHCTUNGTREG(NNNU thiourea) receptors as well as imparting a positive charge
chloroform. X is the mole fraction of the host.
that makes them more effective as anion hosts as compared
with the free ligands. Metal coordination can also remove
the possibility of competing ligand–ligand hydrogen-bonding
interactions. The strong coordination of sulfur donor ligands
and second- and third-row transition-metal complexes, along
with the terdentate chelate nature of the complexes in com-
pounds of type 2 and 4 means that these species are stable
even in highly competitive solvents, such as DMSO, and
function as effective anion-binding hosts. In addition to the
single host does not cover more than half of the anion sur-
face. Similar 2:1 complexes have been observed in other or-
ganometallic anion hosts.[70] In the more competitive
DMSO, both 1:1 and 2:1 binding constants for 2b’ chloride
complexes were obtained and the complex again proved to
be a stronger anion-binding receptor than the free ligand
(Table 1). In acetone, 2b’ bound strongly in a similar 1:1 and
2:1 stoichiometry with all other anions studied except
1
usual H NMR spectroscopic titration, 19F NMR spectrosco-
py has been shown to be an effective complementary tool
for the study of anion-binding processes.
À
À
ReO4 , which did not displace the BF4 counterion, and ace-
tate, which resulted in loss of the NH resonance due to host
deprotonation.
Complex 4 also proved to be an effective anion receptor
in both chloroform and DMSO. The coordination of the pyr-
idyl nitrogen atom makes the thiourea NH groups available
for anion complexation and thus the coordination-induced
enhancement is very significant compared to the negligible
binding observed for the free ligand. Interestingly, a Job
plot for this receptor (Figure 11b) suggested a mixture of 1:1
and 1:2 host–guest complexes with each of the two diverging
coordinated thiourea groups binding to a single anion in this
non-competitive medium, albeit in a non-cooperative fash-
ion. The data proved difficult to fit without the introduction
of a host dimerisation equilibrium for all anions, logb20 =
2.07. Thiourea self-association in non-competitive solvents is
known[111] and appears to be in competition with anion bind-
ing. However, the speciation behaviour was reversed in the
more competitive DMSO, with the formation of 1:1 and 2:1
host–guest complexes similarly to 2b’. Complexation of two
anions in DMSO may be inhibited by solvent competition.
The 19F NMR spectroscopic data for the displacement of
Experimental Section
General procedures: All procedures were carried out under an atmos-
phere of dry oxygen-free nitrogen by using standard Schlenk techniques.
Elemental analyses were performed by using a Carlo Erba Instruments
EA 1108 CHNS/O microanalyser. IR spectra were recorded by using a
Shimadzu IRPRESTIGE-21 spectrophotometer using
a pure solid
sample over an ATR device (4000–700 cmÀ1 range). FAB mass spectra
were recorded by using a VG Biotech Quattro Spectrometer. NMR spec-
tra were recorded at RT (258C) by using Varian Unity Inova-400
(400 MHz for H; 100.6 MHz for 13C) and Varian Inova FT-500 (500 MHz
1
for 1H; 125 MHz for 13C) spectrometers. 1H shifts (ppm) were recorded
by using the residual proton of the solvent as the internal standard. Sol-
vents were supplied by SDS (reactive degree), and distilled from the ap-
propriate drying agents and degassed before use. Starting materials
[{Ru(h6-C6H4MeCH(Me)2)Cl
[Pt
(MeCN)2Cl2],[112] [Pt
G
[{IrACHTNGUTRENNUG CAHTUNGTRENNNUG
(h5-C5Me5)Cl(m-Cl)}2],[105]
G
ACHTUNGTRENNUNG
according to literature procedures. AgBF4 and isothiocyanate derivatives
were purchased from Aldrich and used without further purification.
Anion titration
Job plot: Equimolar solutions of the host (2.9 mm) and guest in
[D6]acetone and [D6]DMSO were prepared and mixed in various ratios.
1H and 19F NMR spectra of the solutions were recorded, and the change
À
BF4 by the more strongly bound anion guests is shown in
Figure 9. This data bears out the 1:2 limiting stoichiometry
10826
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ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 10818 – 10831

Anion Binding
FULL PAPER
in the chemical shifts of the protons of the amine groups and the fluorine
atoms of the BF4 counterion were analysed.
Synthesis of metal complexes
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L2ÀH)]Cl
(2a):
[{Ru(h6-
Titration: 1H NMR spectroscopic titration experiments were carried out
by using a Varian Inova 500 MHz NMR spectrometer. All chemical shifts
are reported in ppm relative to tetramethylsilane as an internal reference.
A known concentration of the host species (typically 0.06m) in deuterat-
ed solvent (0.5 mL) was made up in a NMR tube. Solutions of the anions
C6H4MeCH(Me)2)ClACTHNUTRGNENUG(m-Cl)}2] (0.31 g, 0.5 mmol) was dissolved in chloro-
form (50 mL) that had been degassed for 30 min with N2. Under a nitro-
gen atmosphere, L2 (0.25 g, 1.0 mmol) was added and dissolved in the re-
action mixture, which was then heated at reflux for 4 h. All solvent was
then removed in vacuo to provide a crude product that displayed many
broad resonances in the 1H NMR spectrum. The crude product was dis-
solved in distilled water (50 mL) and filtered to remove a dark residue.
The aqueous solution was washed with chloroform (5ꢂ20 mL) to extract
the desired product. The combined organic fractions were dried
(MgSO4), filtered and all solvent was removed in vacuo to give an orange
solid (yield=0.4 g, 0.76 mmol, 76%). 1H NMR (CDCl3, 400 MHz): d=
1.07 (d, 3J=7.2 Hz, 3H; N-CH3), 1.16 (d, 3J=7.2 Hz, 3H; N-CH3), 2.05
(s, 3H; Ar-CH3), 2.62 (m, 1H; CH cym) 2.77 (d, 3J=4.8 Hz, 3H; C-CH3
+
(as NBu4 salts) were made up in the same deuterated solvent in volu-
metric flasks (2 mL) at a concentration five times greater than the host.
The solution of the guest was titrated into the host solution at initial vol-
umes of 10 mL (0.1 equiv with respect to the host) and homogenised by
rigorous shaking, then spectra were recorded after each addition. Larger
aliquots were added when little change was observed in the spectra. Re-
sults were analysed by using the curve-fitting program HypNMR 2006, si-
multaneously fitting as many resonances as could be accurately moni-
tored during the experiment.
3
3
iPr), 2.99 (d, J=4.8 Hz, 3H; C-CH3 iPr), 5.03 (d, J=5.6 Hz, 1H; CHAr
)
5.07 (d, 3J=5.6 Hz, 1H; CHAr), 5.16 (d, 3J=5.6 Hz, 1H; CHAr), 5.21 (d,
3J=5.6 Hz, 1H; CHAr), 5.44, (q, 3J=7.2 Hz, 1H; NH(Me)), 7.12 (br, s,
1H; CHAr), 7.13 (br, s, 1H; CHAr), 7.21 (br, s, 1H; CHAr), 7.23 (br, s, 1H;
CHAr), 8.82 (q, 3J=7.2 Hz, 1H; NH(Me)), 10.94 ppm (s, 1H; NH(Ar));
{1H}13C NMR (CDCl3, 400 MHz): d=18.75, 22.09, 22.77, 28.67, 31.46,
32.49, 82.22, 82.74, 82.85, 82.89, 97.55, 104.20, 126.09, 126.21, 127.10,
Synthesis of ligands
Methyl-3-[2-(3-methylthioureido)ethyl]thiourea (L1): Ethylenediamine
(0.60 g, 10.3 mmol) and methylisothiocyanate (1.6 g, 21.9 mmol) were dis-
solved in dichloromethane (30 mL), and the solution was heated at reflux
for 1.5 h. After this time, the white precipitate was removed by filtration
(yield=1.9 g, 9.2 mmol, 89%). 1H NMR (CD3CN/[D6]DMSO, 400 MHz)
d=2.88 (br, s, 6H; CH3), 3.58 (br, s, 4H; CH2), 7.10 (br, s, 2H; NH-
À
127.17, 132.91, 140.83, 181.43, 182.47 ppm; IR: n˜ =3192 (br, N H), 3044
À1
(CH3)); {1H}13C NMR ([D6]DMSO,
ACHTUNGTRENNUNG(CH2)), 7.23 ppm (br, s, 2H; NHHCATUNGTRENNUGN
101 MHz) d=31.15, 43.49, 182.68 ppm; IR: n˜ =3267 (br, N H), 3209 (br,
À
(br, N H), 1595 (s, NH), 1567 (s, NH), 1263 (m, C=S), 1040 cm (m, C=
S); ESI-MS: m/z: 489.1 [102Ru(h6-C6H4MeCH(Me)2)
A
À
À1
isotope envelope); elemental analysis calcd (%) for RuC20H27N4S2Cl: C
45.83, H 5.19, N 10.69; found: C 45.84, H 5.60, N 10.50.
À
N H), 1557 (s, NH), 1224 (m, C=S), 1063 cm (m, C=S); EI-MS: m/z:
206 [M]+; elemental analysis calcd (%) for C6H14N4S2: C 34.93, H 6.84, N
[Ru(h6-C6H4MeCHMe2)(kS,S’,N-L3ÀH)]Cl
(2b):
[{Ru(h6-
27.15; found: C 34.74, H 6.96, N 27.18.
C6H4MeCH(Me)2)ClACTHNUTRGNEUNG
(m-Cl)}2] (79 mg, 0.13 mmol) and L3 (81 mg,
Methyl-3-[2-(3-methylthioureido)phenylene]thiourea (L2): 1,2-Phenylene-
diamine (0.88 g, 8.2 mmol) was dissolved in methanol (50 mL) and slowly
added (ca. 1 h) to a stirred solution of methylisothiocyanate (1.28 g,
17.6 mmol) in methanol (30 mL). The mixture was heated at reflux for
2 h. The solvent was removed in vacuo and the resulting solid was
washed with anhydrous diethyl ether (2ꢂ10 mL) and methanol (4ꢂ
5 mL) to give a white solid (yield=1.35 g, 5.3 mmol, 65%). 1H NMR
([D6]DMSO, 300 MHz): d=2.89 (br, s, 6H; CH3), 7.20 (br, s, 2H; CHAr),
7.41 (br, s, 2H; CHAr), 7.73 (br, s, 2H; NH), 9.03 ppm (br, s, 2H; NH);
{1H}13C NMR ([D6]DMSO, 101 MHz): d=31.81, 126.62, 128.18, 134.23,
0.26 mmol) were dissolved in CHCl3 (25 mL) and stirred at RT for 3 h.
The crude product was obtained by removing all solvent in vacuo
(150 mg), and was then sonicated for 10 min in distilled water to dissolve
the product. The aqueous solution was filtered to remove any undis-
solved material and extracted with CHCl3 (3ꢂ8 mL). The orange organic
fraction was dried (MgSO4) and filtered, then all solvent was removed in
vacuo to give an orange solid (yield=55 mg, 0.095 mmol, 65%).
1H NMR (acetone, 400 MHz): d=1.08 (d, 3J=6.90 Hz, 3H; Mea’), 1.10
(d, 3J=6.6 Hz, 3H; Mea), 1.20 (d, 3J=6.6 Hz, 3H; Meb’), 1.23 (d, 3J=
3
À
À
6.0 Hz, 3H; Meb), 1.24 (d, J=6.0 Hz, 6H; Mec,d), 2.12 (s, 3H; Me’), 2.70
182.21 ppm; IR: n˜ =3275 (br, N H), 3224 (br, N H), 1613 (s, NH), 1262
(s, C=S), 1055 cmÀ1 (s, C=S); ESI-MS: m/z: 255.1 [M+H]+ (100); ele-
mental analysis calcd (%) for C10H14N4S2: C 47.22, H 5.55, N 22.03;
found: C 47.04, H 5.64, N 21.66.
(sept., 3J=6.9 Hz, 1H; CH (H7’)), 3.88 (m, 1H; CH (H8)), 4.38 (m, 1H;
CH (H10)), 5.30 (d, 3J=5.5 Hz, 2H; H3’, 5’), 5.39 (d, 3J=5.8 Hz, 1H; H2’),
5.47 (d, 3J=5.5 Hz, 1H; H6’), 6.78 (d, 3J=8.35 Hz, 1H; NHb), 7.06 (d,
3
3
3J=7.6 Hz, 1H; H6), 7.13 (dd, J=7.3, 7.6 Hz, 1H; H5), 7.19 (dd, J=7.3,
7.6 Hz, 1H; H4), 7.37 (d, 3J=7.6 Hz, 1H; H3), 10.85 (d, 3J=6.9 Hz, 1H;
NHc), 11.69 ppm (s, 1H; NHa); 1H NMR (CDCl3, 400 MHz): d=1.03 (d,
3J=6.0 Hz, 3H; CH3 (L, iPr)), 1.04 (d, 3J=6.0 Hz, 3H; CH3 (L, iPr)),
1.13 (d, 3J=6.0 Hz, 3H; CH3 (L, iPr)), 1.15 (d, 3J=6.0 Hz, 3H; CH3 (L,
iPr)), 1.23 (d, 3J=6.0 Hz, 3H; CH3 (cym, iPr)), 1.28 (d, 3J=6.0 Hz, 3H;
CH3 (cym, iPr)), 2.03 (s, 3H; CH3 (cym)), 2.60 (sept., 3J=6.0 Hz, 1H;
CH (cym)), 3.78 (m, 1H; CH (L)), 4.35 (m, 1H; CH (L)), 4.89 (d, 3J=
8.0 Hz, 1H; NH), 5.03, 5.04 (d, 3J=6.0 Hz, 2H; HAr (cym)), 5.14 (d, 3J=
6.0 Hz, 1H; HAr (cym)), 5.21 (d, 3J=6.0 Hz, 1H; HAr (cym)), 7.09, 7.11,
7.12 (m, 3H; HAr (L)), 7.33 (m, 1H; HAr (L)), 9.91 (d, 3J=8.0 Hz, 1H;
NH), 11.08 ppm (s, 1H; NH); {1H}13C NMR (CDCl3, 500 MHz): d=
19.05, 22.03, 22.63, 22.69, 22.93, 23.11, 23.61, 31.67, 44.78, 48.38, 82.50,
83.13, 83.38, 83.64, 98.07, 104.44, 126.35, 126.88, 126.95, 127.00, 133.03,
Isopropyl-3-[2-(3-isopropylthioureido)phenylene]thiourea (L3): 1,2-Phe-
nylenediamine (0.7 g, 6.5 mmol) and isopropyl isothiocyanate (1.5 g,
14.8 mmol) were sonicated together for 5 min in hot EtOH (2 mL). Crys-
tals suitable for X-ray crystallography crystallised from solution over the
course of 2 d, and more product could be isolated from the mother liquor
over a period of a few days (yield=1.9 g, 6.1 mmol, 95%). 1H NMR
([D6]acetone, 400 MHz): d=1.21 (d, 3J=6.4 Hz, 12H; C-(CH3)2), 4.50
(br, s, 2H; CH-(Me)2), 7.05 (br, s, 2H; NH), 7.24 (m, 2H; CHAr), 7.45
(br, s, 2H; CHAr), 8.43 ppm (br, s, 2H; NH); {1H}13C NMR ([D6]DMSO,
101 MHz): d=22.31, 46.41, 126.52, 128.24, 134.36, 180.06 ppm; IR: n˜ =
À1
À
À
3315 (br, N H), 3256 (br, N H), 1598 (s, NH), 1264 (s, C=S), 1126 cm
(s, C=S); ESI-MS: 311.1 [M+H]+ (100); elemental analysis calcd (%) for
C14H22N4S2: C 54.16, H 7.14, N 18.04; found: C 54.15, H 7.23, N 18.02.
1-Methyl-3-[6-(3-methylthioureido)pyridin-2-yl]thiourea (L4): 2,6-Diami-
nopyridine (1.0 g, 9.2 mmol) and methylisothiocyanate (1.5 g, 20.5 mmol)
were dissolved in methanol (20 mL) and heated at reflux for 4H; then
cooled and the grey precipitate was filtered off (yield=0.97 g, 3.8 mmol,
42%). 1H NMR ([D6]DMSO, 400 MHz): d=3.03 (d, 3J=4.4 Hz, 6H;
CH3), 6.90 (d, 3J=8.4 Hz, 2H; HAr), 7.66 (t, 3J=8.4 Hz, 1H; HAr), 9.75
(br, s, 2H; NHMe), 10.36 ppm (br, s, 2H; NH(Ar)); {1H}13C NMR
([D6]DMSO, 101 MHz): d=32.04, 106.60, 140.72, 150.92, 180.33 ppm; IR:
À
À
140.77, 178.62, 180.20 ppm; IR: n˜ =3216 (br, N H), 3132 (br, N H), 1591
À1
À
À
(s, N H), 1561 (s, N H), 1168 (m, C=S), 1129 cm (m, C=S); ESI-MS:
m/z: 545.1 [102Ru(h6-C6H4MeCHMe2)(kS,S’,N-L3ÀH)]+ (100; Ru isotope
envelope); elemental analysis calcd (%) for RuC24H35N4S2Cl: C 49.68, H
6.08, N 9.66; found: C 48.70, H 6.08, N 9.33.
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L1ÀH)]Cl·H2O (3): Compound 3 was
prepared by using [{Ru(h6-C6H4MeCH(Me)2)Cl
ACHTNUTRGNE(NUG m-Cl)}2] (80 mg,
0.13 mmol) and L1 (54 mg, 0.26 mmol) in a similar procedure to 2a
(yield=88 mg, 0.18 mmol, 68%). 1H NMR (CDCl3, 400 MHz, two con-
formers were in ꢀ2:1 ratio): major conformer: d=1.26, 1.27 (d, 3J=
6.0 Hz, 6H; CH3 cym), 2.22 (s, 3H; CH3 L), 2.67 (s, 3H; CH3 L), 2.76
(sp, 3J=6.0 Hz, 1H; CH cym), 2.97 (br, s, 3H; CH3 cym), 3.07 (m, 1H;
À
À
n˜ =3238 (s, N H), 1633 (m, N H), 1618 (s), 1225 (s, C=S), 1156 (s, C=S),
1066 cmÀ1 (s, C=S); ESI-MS (MeCN): m/z: 256.0 [M+H]+ (100); elemen-
tal analysis calcd (%) for C9H13N5S2: C 42.33, H 5.13, N 27.42; found: C
42.29, H 5.13, N 27.43.
Chem. Eur. J. 2010, 16, 10818 – 10831
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
10827

J. W. Steed et al.
CH2 L), 3.57 (m, 1H; CH2 L), 3.79 (m, 1H; CH2 L), 3.97 (m, 1H; CH2
L), 5.12 (br, s, 1H; CHAr), 5.24 (br, s, 1H; CHAr), 5.32 (br, s, 1H; CHAr),
5.38 (br, s, 1H; CHAr), 6.21 (br, s, 1H; NH), 7.41 (br, s, 1H; NH),
N
(100;
Ru
isotope
envelope);
519.0
[
102Ru(h6-
A
ACHTUNGTRENNUNG
ACHTUNGRTEN(NUNG H2O): C 47.50, H 4.68, 7.23;
3
9.22 ppm (br, s, 1H; NH); minor conformer: d=1.26, 1.27 (d, J=6.0 Hz,
6H; CH3 cym), 2.22 (s, 3H; CH3 L), 2.67 (s, 3H; CH3 L), 2.76 (sp, 3J=
6.0 Hz, 1H; CH cym), 3.00 (br, s, 3H; CH3 cym) 3.07 (m, 1H; CH2 L),
3.31 (m, 1H; CH2 L), 3.57 (m, 1H; CH2 L), 3.97 (m, 1H; CH2 L), 5.12
(br, s, 1H; CHAr), 5.24 (br, s, 1H; CHAr), 5.32 (br, s, 1H; CHAr), 5.42 (br,
s, 1 H; CHAr), 6.44 (br, s, 1H; NH), 8.14 (br, s, 1H; NH), 9.29 ppm (br, s,
1H; NH); {1H}13C NMR (CDCl3, 400 MHz): d=18.99, 22.60, 23.21, 27.99,
31.83, 45.48, 46.92, 81.11, 82.47, 97.54, 104.47, 177.16, 180.79 ppm; ESI-
[Pd
DPPE (92 mg, 0.23 mmol) were dissolved in dichloromethane (20 mL)
and stirred for 30 min to generate Pd(dppe)Cl2 in situ, then a solution of
(kS,S’-L3)]
ACTHUNGTERN(NNUG dppe)ACHTUNGTRNEUNG AHCTUNGRET(GNNNU PF6)2 (6a): PdACHTNGUTREN(UNNG MeCN)2Cl2 (60 mg, 0.23 mmol) and
AHCTUNGTRENNUNG
L3 (72 mg, 0.23 mmol) in acetone (20 mL) was added. The solution was
stirred for 5 H; then all solvent was removed in vacuo and the yellow
solid was washed with hexane to give the crude product (180 mg). This
crude product (90 mg) was dissolved in acetone/ethanol (50 mL; 1:1)
before NH4PF6 (200 mg, excess) was added and the mixture stirred over-
night. All solvent was then removed and the compound was extracted
into CDCl3 (2 mL) for NMR spectroscopy studies. After spectra had
been obtained, all solvent was removed from this solution to give a
yellow solid that was washed with diethyl ether (yield=101 mg,
0.09 mmol, 89% based on 90 mg crude solid used in metathesis).
1H NMR (CDCl3, 400 MHz): d=1.25 (br, s, 6H; CH3 L), 2.37 (br, s, 2H;
CH2 DPPE), 2.82 (br, s, 2H; CH2 dppe), 4.28 (br, s, 2H; CH L), 5.91 (br,
s, 2 H; CHAr), 6.39 (br, s, 2H; CHAr), 7.38, 7.47, 7.60 (br, s, 20H; CHAr
dppe), 7.82 (br, s, 2H; NH), 8.7 ppm (br, s, 2H; NH); {1H}13C NMR
(CDCl3, 101 MHz): d=21.13, 21.33, 29.88, 47.35, 127.63, 128.53, 128.64,
130.47, 131.67, 131.76, 131.86, 132.10, 132.81, 132.92, 175.07 ppm;
MS: 441.2 [102Ru(h6-C6H4MeCH(Me)2)
ACHTUNGTRENNUNG
lope); elemental analysis calcd (%) for RuC16H27N4S2Cl.H2O: C 38.89, H
5.92, N 11.34; found C 38.77, H 5.96, N 10.91.
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L4)]Cl2
(4):
[{Ru(h6-
C6H4MeCH(Me)2)Cl
ACHTUNGTRENNUNG
1.54 mmol) were dissolved in degassed CH2Cl2 (40 mL) and heated at
reflux under N2 for 6 h. Orange crystals were obtained after concentrat-
ing the resultant red solution and crystallised by adding a layer of diethyl
ether at 58C. Filtering and drying the crystals gave the pure product. Ad-
dition of water causes the formation of two isomers, the main one corre-
sponds to a symmetric species while the minor one is asymmetric and is
likely to arise from deprotonation (yield=178 mg, 0.33 mmol, 95%).
1H NMR (CDCl3, 700 MHz): d=1.23 (d, 3J=6.9 Hz, 6H; Me cym), 1.89
1
{1H}31P NMR (CDCl3, 162 MHz): d=61.64 (s, PPh2), À144.02 ppm (sp, J-
3
3
À
À
À
(s, 3H; Me cym), 2.74 (sp, J=6.9 Hz, 1H; CH cym), 3.31 (d, J=4.9 Hz,
ACHTUNGTREN(UNNG P,F)=715 Hz, PF6); IR: n˜ =3353 (br, N H), 3220 (br, N H), 1578 (s, N
3
3
H), 1243 (m, C=S), 1167 (m, C=S), 1104 (m, C=S), 840 cmÀ1 (vs, P F);
À
6H; Me), 5.53 (d, J=6.1 Hz, 2H; HAr cym), 5.66 (d, J=6.1 Hz, 2H; HAr
cym), 7.37 (d, J=8.0 Hz, 2H; Hpy), 7.67 (t, 3J=8.0 Hz, 1H; Hpy), 10.55
ESI-MS: m/z: 812.9 [106Pd
N
(L3ÀH)]+ (100; Pd isotope envelope);
3
(q, 3J=4.6 Hz, 2H; NH), 13.01 ppm (s, 2H; NH); {1H}13C NMR (CDCl3,
700 MHz): d=18.62 (Me’), 22.79 (Me’’), 30.91 (CH cym), 32.35 (Me), 88.32
(C3cym), 89.83 (C2cym), 105.88 (C4cym), 107.38 (C1cym), 112.79 (C3py), 142.38-
À
elemental analysis calcd (%) for PdC40H46N4S2P4F12: C 43.47, H 4.19, N
5.04; found: C 44.54, H 4.19, N 5.16.
[Pt
DPPE (114 mg, 0.29 mmol) were dissolved in CH2Cl2 (20 mL) to form Pt-
AHCTUNGTRENNUNG
(dppe)Cl2 in situ, then L3 (78 mg, 0.29 mmol) in ethanol (20 mL) was
(kS,S’-L3]
ACTHUNGTERN(NNUG dppe)ACHTUNGTERNNGU ACHTUNGETRN(GUNN PF6)2 (6b): PtACHTNGUTREN(UNGN MeCN)2Cl2 (100 mg, 0.29 mmol) and
ACHTUNGTRENNUNG
(C4py), 153.62 (C2py), 179.74 ppm (C=S); IR: n˜ =3167 (br, N H), 1621 (s,
À
N H), 1563 and 1545 (m, C=N), 1273 (m, C=S), 1180 (m, C=S),
1052 cmÀ1
C6H4MeCH(Me)2)L]2+
(m,
C=S);
265.5
ESI-MS:
m/z:
245.5
[
102Ru(h6-
(MeCN)]2+
;
added and the mixture was stirred for 2 h at RT. Then NH4PF6 (200 mg,
excess) in acetone (10 mL) was added and the mixture was stirred for a
further 1 h. All solvent was then removed in vacuo and the yellow solid
was washed with CH2Cl2. The organic fraction was dried in vacuo to give
,
[
102Ru(h6-C6H4MeCH(Me)2)L
U
elemental analysis calcd (%) for RuC19H27N5S2Cl2: C 40.64, H 4.85, N
12.47; found: C 40.43, H 4.76, N 12.28.
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,Npy-L4)]
N
a
yellow solid (yield=140 mg, 0.12 mmol, 40%). 1H NMR (CDCl3,
0.11 mmol) was dissolved in degassed CH2Cl2 (10 mL) and AgBF4
(41.6 mg, 0.21 mmol) was added to produce a precipitation of AgCl. An
orange powder was obtained by filtration of the solution and removal of
the solvent by vacuum (yield=178 mg, 0.33 mmol, 97%). 1H NMR
(CDCl3, 400 MHz): d=1.26 (d, 3J=6.9 Hz, 6H; Me cym), 1.89 (s, 3H;
Me cym), 2.79 (sp, 3J=6.9 Hz, 1H; CH cym), 3.38 (br, s, 6H; Me), 5.74
200 MHz): d=1.20 (d, 3J=6.4 Hz, 6H; CH3), 1.28 (d, 3J=6.4 Hz, 6H;
CH3), 2.0 (br, s, 2H; CH2), 2.7 (br, s, 2H; CH2), 4.26 (q, 3J=6.4 Hz, 2H;
3
3
CH), 6.00 (d, J=4.6 Hz, 2H; CHAr), 6.41 (d, J=4.6 Hz, 2H; CHAr), 7.06
(br, s, 2H; NH), 7.4–7.6 (m, 20H; CHAr), 8.68 ppm (br, s, 2H; NH);
{1H}13C NMR (CDCl3, 101 MHz): d=21.22, 29.92, 47.68, 124.60, 125.20,
126.13, 126.74, 127.03, 127.34, 127.64, 128.51, 130.14, 131.44, 132.07,
132.89, 173.44 ppm; {1H}31P NMR (CDCl3, 121 Hz): d=45.87 (s with Pt
3
3
(d, J=6.1 Hz, 2H; HAr cym), 5.82 (d, J=6.1 Hz, 2H; HAr cym), 7.25 (d,
3J=8.0 Hz, 2H; Hpy), 7.77 (t, 3J=8.0 Hz, 1H; Hpy), 9.08 (br, s, 2H;
NH), 10.51 ppm (s, 2H; NH); 19F NMR (CDCl3, 400 MHz): d=
satellites, 1J
G
E
ACHTUNGTREN(NUNG P,F)=715 Hz,
À
PF6); IR: n˜ =3345 (br, N H stretch), 3246 (br, N H stretch), 1574 (s, NH
À149.06 ppm; IR: n˜ =3318 (br, N H), 1613 (s, N H), 1558 (m, C=N),
bend), 1166 (m, C=S stretch), 1105 (m, C=S stretch), 840 cmÀ1 (vs, P F);
À
À
À
1282 (m, C=S), 1185 (m, C=S), 1024 cmÀ1 (br, B F); elemental analysis
ESI-MS: m/z: 905.3 [195Pt
À
calcd (%) for RuC19H27N5S2B2F8: C 34.36, H 4.10, N 10.54; found: C
mental analysis calcd (%) for PtC40H46N4S2P4F12: C 40.24, H 3.88, N 4.69;
34.29, H 4.25, N 9.99.
found: C 40.14, H 3.98, N 5.03.
[Ru(h6-C6H4MeCH(Me)2)Cl(kS,Npy-L5)]Cl·2H2O
(5):
[{Ru(h6-
[Pd
0.19 mmol) and DPPE (77 mg, 0.19 mmol) in CH2Cl2 (20 mL) was stirred
for 30 min to generate Pd
(dppe)Cl2 in situ, then L1 (39 mg, 0.19 mmol) in
ACHTUNGTRNEU(GNN dppe)ACHTUNRTEGNNUNG ACHTNGUTREN(NGUN MeCN)2Cl2 (50 mg,
(kS,S’-L1)]Cl·PF6 (7): A solution of Pd
C6H4MeCH(Me)2)Cl
ACHTUNGTRENNUNG
0.25 mmol) were heated at reflux under N2 in degassed CHCl3 for 3 h.
All solvent was then removed in vacuo to give a dark orange solid
(yield=124 mg, 0.21 mmol, 84%). 1H NMR (CDCl3, 400 MHz): d=1.13
ACHTUNGTRENNUNG
ethanol (20 mL) was added. This mixture was stirred for 1 h before an
excess of NH4PF6 (120 mg) in ethanol (20 mL) was added and the mix-
ture was stirred for a further 30 min. All solvent was then removed and
the compound was extracted into chloroform (20 mL). The solvent was
removed from this solution to give a yellow solid that was washed with
diethyl ether (yield=142 mg, 0.16 mmol, 84%). 1H NMR (CD3CN,
400 MHz): d=2.65 (br, s, 6H; CH3), 2.72 (br, s, 4H; CH2), 3.32 (br, s,
2H; CH2), 3.43 (br, s, 2H; CH2), 6.83 (br, s, 2H; NH), 7.58 (br, s, 8H;
CHAr), 7.67 (br, s, 4H; CHAr), 7.80 (br, s, 8H; CHAr), 8.26 ppm (br, s,
3
3
(d, J=4.4 Hz, 3H; CH3 cym), 1.15 (d, J=4.4 Hz, 3H; CH3 cym), 1.87 (s,
3
3H; CH3), 2.32 (s, 3H; CH3), 2.71 (m, 1H; CH, cym), 5.22 (d, J=6.0 Hz,
1H; CHAr, cym), 5.24 (d, 3J=6.0 Hz, 1H; CHAr, cym), 5.38 (d, 3J=
6.0 Hz, 1H; CHAr, cym), 5.46 (d, 3J=6.0 Hz, 1H; CHAr, cym), 7.13, (d,
3J=6.8 Hz, 1H; CHAr, pyridyl), 7.17 (d, 3J=8.4 Hz, 2H; CHAr, tolyl),
3
7.41 (d, J=8.4 Hz, 2H; CHAr, tolyl), 7.56 (d, 3J=6.8 Hz, 1H; CHAr, pyr-
idyl), 7.73 (t, 3J=6.8 Hz, 1H; CHAr, pyridyl), 8.83 (d, 3J=6.8 Hz, 1H;
CHAr, pyridyl), 11.95 (br, s, 1H; NH), 13.11 ppm (br, s, 1H; NH);
{1H}13C NMR (CDCl3, 101 MHz): d=17.19, 20.21, 21.29, 21.39, 29.69,
83.40, 84.05, 84.24, 85.76, 99.16, 105.96, 116.13, 120.32, 124.14, 128.70,
132.91, 136.87, 139.241, 152.00, 153.76, 176.79 ppm; IR (NH peaks ob-
2H; NH); {1H}31P NMR (CDCl3, 162 MHz): d=À136.2 (sept., 1J
ACHTUNGTRENNUNG(P,F)=
715 Hz, PF6), 67.9 ppm (s, PPh2); IR: 3385 (br), 3241 (br), 1588 (s), 1229
(m, C=S), 1188 (m, C=S), 1104 (m, C=S), 840 cmÀ1 (vs, P F); ESI-MS
À
(MeCN): m/z: 709.1 [106Pd
(dppe)
R
À
scured by H2O peak): n˜ =1628 (s, N H), 1219 (m, C=S), 1160 (m, C=S),
elemental analysis calcd (%) for PdC32H38N4S2P3F6Cl: C 43.11, H 4.30, N
6.28; found: C 43.39, H 4.00, N 3.82.
1057 cmÀ1 (m, C=S); ESI-MS: m/z: 478.0 [102Ru(h6-C6H4MeCH(Me)2)-
10828
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 10818 – 10831

Anion Binding
FULL PAPER
[Pd
DPPE (77 mg, 0.19 mmol) were dissolved in CH2Cl2 (20 mL) and stirred
for 30 min to generate [Pd
(dppe)Cl2] in situ, then L4 (48 mg, 0.19 mmol)
(dppe)
E
E
(No. 2); a=10.0505(6), b=11.2786(7), c=13.1434(8) ꢁ; a=71.008(2), b=
73.421(2), g=83.534(2)8; V=1349.89(14) ꢁ3; Z=2; 1calcd =1.427 gcmÀ3
;
F000 =600; SMART 6000; T=120(2) K; 2qmax =58.38; 23947 reflections
in ethanol (20 mL) was added. This mixture was stirred for 1 h before an
excess of NH4PF6 (120 mg) in ethanol (20 mL) was added. The mixture
was stirred for a further 30 min, then all solvent was removed and the
compound was extracted into CHCl3 (20 mL). The solvent was then re-
moved to give a yellow solid that was washed with diethyl ether (yield=
157 mg, 0.17 mmol, 88%). 1H NMR (CDCl3, 400 MHz): d=2.66 (m, 2H;
collected, 7277 unique (Rint =0.0227); final GOF=1.040; R1 =0.0244,
wR2 =0.0601, R indices based on 6538 reflections with I>2s(I) (refine-
ment on F2), 308 parameters, 0 restraints; LP and absorption corrections
applied; m=0.853 mmÀ1
.
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L1ÀH)]Cl·H2O (3): Diffraction-quality
single crystals were obtained by slow evaporation of a solution of the
complex in acetone/diethyl ether. Crystal data for C16H29ClN4ORuS2:
Mr =494.07; red block; 0.30ꢂ0.20ꢂ0.20 mm3; monoclinic; space group
P21/c (No. 14); a=15.238(3), b=11.869(2), c=11.441(2) ꢁ; b=
3
CH2-P), 2.72 (m, 2H; CH2-P), 2.98 (d, J=4.4 Hz, 6H; CH3-N), 6.98 (br,
3
s, 2 H; CHAr (L)), 7.38 (br, s, 1H; CHAr (L), 7.45 (d, J=6.0 Hz, 8H; Ph-
P), 7.54 (d, 3J=6.4 Hz, 4H; Ph-P), 7.70 (dd, 3J=6.4, 6.0 Hz, 8H; Ph-P),
9.26 (br, s, 2H; NH-Me), 10.26 ppm (br, s, 2H; NH-Ar); {1H}31P NMR
94.029(5)8; V=2064.1(7) ꢁ3; Z=4; 1calcd =1.590 gcmÀ3
;
F000 =1016;
(CDCl3, 162 MHz): d=À135.7 (sept., 1J
ACHTUNGRTEN(NUNG P,F)=715 Hz, PF6), 66.5 ppm (s,
SMART 1000; T=120(2) K; 2qmax =58.38; 29337 reflections collected,
5553 unique (Rint =0.0684); final GOF=1.024; R1 =0.0349, wR2 =0.0631,
R indices based on 4347 reflections with I>2s(I) (refinement on F2), 251
parameters; 0 restraints; LP and absorption corrections applied; m=
À
À
PPh2); IR: n˜ =3393 (br, N H), 3170 (br, N H), 1612 (s, NH), 1259 (m,
C=S), 1163 (m, C=S), 1103 (m, C=S), 1052 (m, C=S), 840 cmÀ1 (vs, P F);
À
ESI-MS (MeCN): m/z: 758.1 [106Pd
N
(L4ÀH)]+ (100; Pd isotope en-
1.104 mmÀ1
.
velope); elemental analysis calcd (%) for PdC35H37N5S2P3F6Cl: C 44.69,
H 3.96, N, 7.45; found: C 44.40, H 4.00, N, 6.80.
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,Npy-L4)]Cl2·2CH2Cl2 (4): Diffraction-qual-
ity single crystals were obtained by slow evaporation of a solution of the
complex in dichloromethane. Crystal data for C21H31Cl6N4RuS2: Mr =
547.54; red fragment of block; 0.18ꢂ0.14ꢂ0.12 mm3; monoclinic; space
group P21/n (No. 14); a=13.6090(8), b=17.8909(10), c=13.7951(8) ꢁ;
b=117.888(2)8; V=2968.7(3) ꢁ3; Z=5; 1calcd =1.531 gcmÀ3; F000 =1395;
CCD area detector; T=120(2) K; 2qmax =46.58; 14863 reflections collect-
ed, 4261 unique (Rint =0.0245); final GOF=1.073; R1 =0.0268, wR2 =
0.0647, R indices based on 3751 reflections with I>2s(I) (refinement on
F2), 321 parameters, 0 restraints; LP and absorption corrections applied;
A
ACHTUNGTRENNUNG
a
ACHTUNGTRENNUNG
(123.4 mg, 0.16 mmol) in CH2Cl2 (2 mL) to give an orange solution. The
mixture was stirred for 2 h and a yellow powder was obtained by precipi-
tation with Et2O. Orange single crystals were obtained by diffusion of a
solution of the complex in acetone and Et2O (yield 234 mg, 0.15 mmol,
50%). IR: n˜ =3209 (br, N H), 1260 (s, C=S), 1027 cmÀ1 (s, C=S);
À
MALDI MS: 637.4 [Cp*Ir(L3)]+ (100), 673.3 [Cp*Ir(L)Cl]+ (25), 997.5
[(Cp*Ir)2ACHTUNGTRENNUNG
(L3À4H)Cl]+ (10); elemental analysis calcd (%) for
m=1.073 mmÀ1
(L3·Br): Diffraction-quality single crystals of the bromide complex
NBu4ACTHGNUTRENNUG
.
H74C48N8S4Cl4Ir2·2ACHTUNGTRENNUNG(Me2CO): C 42.29, H 5.65, N 7.31; found C 42.12, H
5.59, N 7.30.
ACHTUNGTRENNUNG[{Cp*IrClACHTUNGTRENNUNG ACHTUNGTRENNUNG(BF4)2 (9’): AgBF4 was added to a solution of 9 in dry
(m-L3)}2]
of L3 were obtained by slow evaporation of a solution of L3 in methanol
in the presence of one molar equivalent of NBu4Br. Crystal data for
C30H58BrN5S2: Mr =632.84; colourless block; 0.40ꢂ0.20ꢂ0.10 mm3; mon-
oclinic; space group P21/m (No. 11); a=8.922(2), b=14.512(3), c=
CH2Cl2 (2 mL) and filtered to give a yellow solution that was concentrat-
ed in vacuo to give a yellow solid that was washed with Et2O (95%
yield). 1H NMR (400 MHz, [D6]DMSO): d=12.40 (s, 1H; NH), 10.51 (s,
1H; NH), 10.09 (s, 1H; NH), 9.84 (s, 1H; NH), 7.97 (t, J=8.1 Hz, 1H;
CHAr), 7.63 (t, J=8.1 Hz, 1H; CHAr), 7.09 (d, J=8.1 Hz, 1H; CHAr), 6.99
13.570(3) ꢁ; b=99.736(5)8; V=1731.7(7) ꢁ3; Z=2; 1calcd =1.214 gcmÀ3
;
F
000 =680; SMART 1000; T=273(2) K; 2qmax =59.28; 17021 reflections
À
(d, J=8.0 Hz, 1H; CHAr), 1.53 ppm (s, 15H; Me); IR: n˜ =3223 (br, N
collected, 4955 unique (Rint =0.1156); final GOF=1.024; R1 =0.0703,
wR2 =0.1134, R indices based on 2748 reflections with I>2s(I) (refine-
ment on F2), 219 parameters, 0 restraints; LP and absorption corrections
H), 1232 (s, C=S), 1096 (s, C=S), 1052 cmÀ1 (s, B F); MALDI MS: m/z:
À
637.3 [Cp*Ir(L)]+ (100), 673.3 [Cp*Ir(L)Cl]+ (25), 997.5 [(Cp*Ir)2-
(LÀ4H)Cl]+ (10); elemental analysis calcd (%) for H74B2C48N8F8S4Cl2Ir2:
applied; m=1.333 mmÀ1
(L4·Cl): Diffraction-quality single crystals of the chloride complex
NBu4ACTHGNUTRENNUG
.
C 42.29, H 5.65, N 7.31; found C 41.92, H 5.91, N 7.37.
of L4 were obtained by slow evaporation of a solution of L4 in methanol
in the presence of one molar equivalent of NBu4Cl. Crystal data for
C21H41ClN6S2: Mr =477.17; colourless block; 0.40ꢂ0.30ꢂ0.20 mm3; mono-
clinic; space group P21/n (No. 14); a=13.7716(8), b=13.8071(8), c=
Crystal structure refinement and analysis: The diffraction experiments,
performed by using graphite-monochromated MoKa radiation (l=
0.71073 ꢁ), were carried out by using SMART 1000, SMART 6000 or
APEX ProteumM instruments (X-rays from a 60 W microfocus Bede Mi-
crosource with glass polycapillary optics), covering a full sphere of the re-
ciprocal space by using three or four runs of narrow-frame (0.38) w scans.
The crystals were cooled by using Cryostream (Oxford Cryosystems)
open-flow N2 cryostats. The structures were solved by direct methods and
refined by full-matrix least-squares on F2 for all data by using SHELXTL
14.1391(8) ꢁ;
b=100.408(2)8;
F000 =1032; SMART 6000; T=120(2) K; 2qmax =58.58;
V=2644.3(3) ꢁ3;
Z=4;
1calcd =
1.199 gcmÀ3
;
37623 reflections collected, 7145 unique (Rint =0.0542); final GOF=
1.008; R1 =0.0366, wR2 =0.0830, R indices based on 5059 reflections with
I>2s(I) (refinement on F2), 293 parameters, 0 restraints; LP and absorp-
software.[113,114] Structure visualisation and figure preparations was carried
tion corrections applied; m=0.322 mmÀ1
[Pd(dppe) (PF6)·
(kS,S’-L3)]Cl
quality single crystals were obtained by slow evaporation of a solution of
the complex in acetone/diethyl ether. Crystal data for
.
116]
out by using X-Seed.[115,
below.
Details of individual structures are given
A
E
N
ACHTUGNERTN(NUNG CH3)2CO (mixed salt of 6a): Diffraction-
[Ru((h6-C6H4MeCH(Me)2)(kS,S’,N-L2ÀH)]Cl (2a): Diffraction-quality
single crystals were obtained by cooling and slow evaporation of a hot so-
lution of [Ru(h6-C6H4MeCH(Me)2)(kS,S,N-L2ÀH)]Cl in ethyl acetate.
Crystal data for C20H27ClN4RuS2: Mr =524.10; red small plate; 0.09ꢂ
C43H52ClF6N4OP3PdS2: Mr =1053.77; colourless block; 0.20ꢂ0.20ꢂ
0.10 mm3; orthorhombic; space group Pbca (No. 61); a=16.7485(17), b=
22.810(2), c=25.016(3) ꢁ; V=9556.7(17) ꢁ3; Z=8; 1calcd =1.465 gcmÀ3
;
0.04ꢂ0.03 mm3; triclinic; space group P1 (No. 2); a=9.9266(9), b=
¯
F
000 =4320; SMART 1000; T=120(2) K; 2qmax =46.68; 81339 reflections
14.8915(13), c=24.231(2) ꢁ; a=74.849(2), b=80.322(2), g=79.488(2)8;
collected, 6897 unique (Rint =0.3378); final GOF=1.042; R1 =0.0848,
wR2 =0.1418, R indices based on 4070 reflections with I>2s(I) (refine-
ment on F2), 563 parameters, 2 restraints; LP and absorption corrections
V=3371.9(5) ꢁ3; Z=6; 1calcd =1.549 gcmÀ3
;
F
000 =1608; APEX; T=
120(2) K; 2qmax =50.08; 54743 reflections collected, 11857 unique (Rint
=
applied; m=0.693 mmÀ1
[{Cp*IrCl(m-S,S’-L3)}2](Cl) ·
.
0.0676); final GOF=1.020, R1 =0.0390, wR2 =0.0794, R indices based on
8771 reflections with I>2s(I) (refinement on F2); 772 parameters, 0 re-
A
E
straints; LP and absorption corrections applied; m=1.016 mmÀ1
.
single crystals were obtained by slow evaporation of a solution of the
[Ru(h6-C6H4MeCH(Me)2)(kS,S’,N-L3ÀH)]Cl (2b): Diffraction-quality
single crystals were obtained by slow evaporation of a solution of the
complex in acetone/diethyl ether. Crystal data for C24H35ClN4RuS2: Mr =
complex in acetone/THF. Crystal data for C105.37H166.74Cl8Ir4N16O3S8: Mr =
3
¯
3014.61; yellow block; 0.30ꢂ0.30ꢂ0.20 mm ; triclinic; space group P1
(No. 2); a=12.1392(2), b=20.3398(3), c=26.2094(4) ꢁ; a=89.7760(10),
580.20; red block; 0.30ꢂ0.20ꢂ0.20 mm3; triclinic; space group P1
b=83.1650(10), g=82.6200(10)8; V=6371.69(17) ꢁ3; Z=2; 1calcd
=
¯
Chem. Eur. J. 2010, 16, 10818 – 10831
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
10829

J. W. Steed et al.
1.571 gcmÀ3
;
F
000 =3014; SMART 6000; T=120(2) K; 2qmax =58.48;
[27] K. P. Xiao, P. Buhlmann, Y. Umezawa, Anal. Chem. 1999, 71,
1183–1187.
[28] S. Nishizawa, T. Yokobori, T. Shioya, N. Teramae, Chem. Lett.
2001, 1058–1059.
[29] S. Nishizawa, H. Kaneda, T. Uchida, N. Teramae, J. Chem. Soc.
Perkin Trans. 2 1998, 2325–2327.
[30] S. Nishizawa, R. Kato, T. Hayashita, N. Teramae, Anal. Sci. 1998,
14, 595–597.
108668 reflections collected, 34444 unique (Rint =0.0482); final GOF=
1.010; R1 =0.0372, wR2 =0.0791, R indices based on 25594 reflections
with I>2s(I) (refinement on F2), 1386 parameters, 0 restraints; LP and
absorption corrections applied; m=4.514 mmÀ1
.
CCDC-777505 (2a), -777506 (2b) -777507 (3) -777508 (4) -777509 (mixed
salt of 6a) -777510 (9) -777511 (NBu4A 4A
(L3·Br)) and -777512 (NBu (L4·Cl))
contain the supplementary crystallographic data for this paper. These
data can be obtained free of charge from The Cambridge Crystallograph-
ic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
C
CHTUNGTRENNUNG
[31] T. Gunnlaugsson, A. P. Davis, M. Glynn, Chem. Commun. 2001,
2556–2557.
[32] T. Gunnlaugsson, A. P. Davis, G. M. Hussey, J. Tierney, M. Glynn,
Org. Biomol. Chem. 2004, 2, 1856–1863.
[33] F.-Y. Wu, Z. Li, Z.-C. Wen, N. Zhou, Y.-F. Zhao, Y.-B. Jiang, Org.
Lett. 2002, 4, 3203–3205.
[34] L. Nie, Z. Li, J. Han, X. Zhang, R. Yang, W. X. Liu, F. Y. Wu, J. W.
Xie, Y. F. Zhao, Y. B. Jiang, J. Org. Chem. 2004, 69, 6449–6454.
[35] Z.-C. Wen, Y.-B. Jiang, Tetrahedron 2004, 60, 11109–11115.
[36] B. Liu, H. Tian, Chem. Lett. 2005, 34, 686–687.
[37] K. Ghosh, S. Adhikari, Tetrahedron Lett. 2006, 47, 8165–8169.
[38] F. M. Pfeffer, A. M. Buschgens, N. W. Barnett, T. Gunnlaugsson,
P. E. Kruger, Tetrahedron Lett. 2005, 46, 6579–6584.
[39] F. M. Pfeffer, M. Seter, N. Lewcenko, N. W. Barnett, Tetrahedron
Lett. 2006, 47, 5241–5245.
[40] D. H. Lee, K. H. Lee, J. I. Hong, Org. Lett. 2001, 3, 5–8.
[41] D. H. Lee, J. H. Im, J. H. Lee, J. I. Hong, Tetrahedron Lett. 2002,
43, 9637–9640.
[42] Y. P. Yen, K. W. Ho, Tetrahedron Lett. 2006, 47, 7357–7361.
[43] S. Sasaki, D. Citterio, S. Ozawa, K. Suzuki, J. Chem. Soc. Perkin
Trans. 2 2001, 2309–2313.
[44] M. Boiocchi, L. Del Boca, D. Esteban-Gomez, L. Fabbrizzi, M. Lic-
chelli, E. Monzani, Chem. Eur. J. 2005, 11, 3097–3104.
[45] D. Esteban-Gꢈmez, L. Fabbrizzi, M. Liechelli, J. Org. Chem. 2005,
70, 5717–5720.
[46] D. E. Gꢈmez, L. Fabbrizzi, M. Licchelli, E. Monzani, Org. Biomol.
Chem. 2005, 3, 1495–1500.
[47] C. M. G. Dos Santos, M. Glynn, T. McCabe, J. S. S. De Melo, H. D.
Burrows, T. Gunnlaugsson, Supramol. Chem. 2007, 20, 407–418.
[48] A. Westcott, C. J. Sumby, R. D. Walshaw, M. J. Hardie, New J.
Chem. 2009, 33, 902–912.
[49] M. George, G. Tan, V. T. John, R. G. Weiss, Chem. Eur. J. 2005, 11,
3243–3254.
Acknowledgements
We thank Junta Castilla-La Mancha for a postdoctoral Fellowship to
M.L.S., and the EPSRC and BP Chemicals Ltd. for a CASE studentship
to J.T.L.
[1] P. D. Beer, P. A. Gale, Angew. Chem. 2001, 113, 502–532; Angew.
Chem. Int. Ed. 2001, 40, 486–516.
[2] T. Gunnlaugsson, M. Glynn, G. M. Tocci, P. E. Kruger, F. M. Pfeff-
er, Coord. Chem. Rev. 2006, 250, 3094–3117.
[3] C. Caltagirone, P. A. Gale, Chem. Soc. Rev. 2009, 38, 520–563.
[4] J. L. Sessler, P. A. Gale, W.-S. Cho, Anion Receptor Chemistry,
RSC, Cambridge, 2006.
[5] Special issue: Anion Coordination Chemistry II, Coord. Chem.
Rev. 2006, 250, 2917–3244.
[6] J. W. Steed, Chem. Soc. Rev. 2009, 38, 506–519.
[7] R. Custelcean, B. A. Moyer, Eur. J. Inorg. Chem. 2007, 1321–1340.
[8] B. M. Maubert, J. Nelson, V. McKee, R. M. Town, I. Pꢃl, J. Chem.
Soc. Dalton Trans. 2001, 1395–1397.
[9] J. A. Gawenis, K. T. Holman, J. L. Atwood, S. S. Jurisson, Inorg.
Chem. 2002, 41, 6028–6031.
[10] P. D. Beer, P. K. Hopkins, J. D. McKinney, Chem. Commun. 1999,
1253–1254.
[11] C. Hogue, Chem. Eng. News 2003, 81, 37–46.
[12] V. Amendola, M. Boiocchi, L. Fabbrizzi, L. Mosca, Chem. Eur. J.
2008, 14, 9683–9696.
[50] S. Nishizawa, P. Bꢆhlmann, K. P. Xiao, Y. Umezawa, Anal. Chim.
Acta 1998, 358, 35–44.
[51] K. H. Choi, A. D. Hamilton, Coord. Chem. Rev. 2003, 240, 101–
110.
[52] S. I. Sasaki, M. Mizuno, K. Naemura, Y. Tobe, J. Org. Chem. 2000,
65, 275–283.
[13] I. Hisaki, S. I. Sasaki, K. Hirose, Y. Tobe, Eur. J. Org. Chem. 2007,
607–615.
[14] L. S. Evans, P. A. Gale, M. E. Light, R. Quesada, New J. Chem.
2006, 30, 1019–1025.
[15] V. Amendola, D. Esteban-Gomez, L. Fabbrizzi, M. Licchelli, Acc.
Chem. Res. 2006, 39, 343–353.
[53] K. H. Lee, J.-I. Hong, Tetrahedron Lett. 2000, 41, 6083–6087.
[54] P. D. Beer, S. R. Bayly, Top. Curr. Chem. 2005, 255, 125–162.
[55] P. D. Beer, E. J. Hayes, Coord. Chem. Rev. 2003, 240, 167–189.
[56] M. G. Fisher, P. A. Gale, M. E. Light, S. J. Loeb, Chem. Commun.
2008, 5695–5697.
[57] C. R. Bondy, P. A. Gale, S. J. Loeb, J. Am. Chem. Soc. 2004, 126,
5030–5031.
[58] C. R. Bondy, P. A. Gale, S. J. Loeb, J. Supramol. Chem. 2002, 2,
93–96.
[59] C. R. Bondy, P. A. Gale, S. J. Loeb, Chem. Commun. 2001, 729–
730.
[60] S. Nieto, J. Perez, L. Riera, V. Riera, D. Miguel, Chem. Commun.
2009, 3279–3281.
[61] V. Amendola, L. Fabbrizzi, Chem. Commun. 2009, 513–531.
[62] J. Pꢉrez, L. Riera, Chem. Soc. Rev. 2008, 37, 2658–2667.
[63] J. Pꢉrez, L. Riera, Chem. Commun. 2008, 533–543.
[64] K. Sato, Y. Sadamitsu, S. Araib, T. Yamagishia, Tetrahedron Lett.
2007, 48, 1493–1496.
[16] F. M. Pfeffer, T. Gunnlaugsson, P. Jensen, P. E. Kruger, Org. Lett.
2005, 7, 5357–5360.
[17] S.-Y. Liu, Y.-B. He, J.-L. Wu, L.-H. Wei, H.-J. Qin, L.-Z. Meng, L.
Hu, Org. Biomol. Chem. 2004, 2, 1582–1586.
[18] R. Martꢄnez-MꢅÇez, F. Sancenon, Chem. Rev. 2003, 103, 4419–
4476.
[19] S. Nishizawa, P. Bꢆhlmann, M. Iwao, Y. Umezawa, Tetrahedron
Lett. 1995, 36, 6483–6486.
[20] T. Gunnlaugsson, A. P. Davis, J. E. OꢇBrien, M. Glynn, Org.
Biomol. Chem. 2005, 3, 48–56.
[21] T. Gunnlaugsson, P. E. Kruger, T. C. Lee, R. Parkesh, F. M. Pfeffer,
G. M. Hussey, Tetrahedron Lett. 2003, 44, 6575–6578.
[22] E. Fan, S. A. Van Arman, S. Kincaid, A. D. Hamilton, J. Am.
Chem. Soc. 1993, 115, 369–370.
[23] S. Nishizawa, P. Buhlmann, M. Iwao, Y. Umezawa, Tetrahedron
Lett. 1995, 36, 6483–6486.
[24] P. Bꢆhlmann, S. Nishizawa, K. P. Xiao, Y. Umezawa, Tetrahedron
1997, 53, 1647–1654.
[65] J. T. Lenthall, J. W. Steed, Coord. Chem. Rev. 2007, 251, 1747–
1760.
[25] D. A. Jose, D. K. Kumar, B. Ganguly, A. Das, Tetrahedron Lett.
2005, 46, 5343–5346.
[26] Y.-J. Kim, H. Kwak, S. J. Lee, J. S. Lee, H. J. Kwon, S. H. Nam, K.
Lee, C. Kim, Tetrahedron 2006, 62, 9635–9640.
[66] C. R. Rice, Coord. Chem. Rev. 2006, 250, 3190–3199.
[67] E. J. OꢇNeil, B. D. Smith, Coord. Chem. Rev. 2006, 250, 3068–3080.
10830
www.chemeurj.org
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2010, 16, 10818 – 10831

Anion Binding
FULL PAPER
[68] R. Custelcean, B. A. Moyer, V. S. Bryantsev, B. P. Hay, Cryst.
Growth Des. 2006, 6, 555–563.
[92] X. Shen, X. Shi, B. Kang, Y. Liu, Y. Tong, H. Jiang, K. Chen, Poly-
hedron 1998, 17, 4049–4058.
[69] A. Channa, J. W. Steed, Dalton Trans. 2005, 2455–2461.
[70] K. J. Wallace, R. Daari, W. J. Belcher, L. O. Abouderbala, M. G.
Boutelle, J. W. Steed, J. Organomet. Chem. 2003, 666, 63–74.
[71] J. A. Tovilla, R. Vilar, A. J. P. White, Chem. Commun. 2005, 4839–
4841.
[72] C. Mendoza, J. Benet-Buchholz, M. A. Pericas, R. Vilar, Dalton
Trans. 2009, 2974–2985.
[73] P. Diaz, D. M. P. Mingos, R. Vilar, A. J. P. White, D. J. Williams,
Inorg. Chem. 2004, 43, 7597–7604.
[74] R. Vilar, D. M. P. Mingos, A. J. P. White, D. J. Williams, Angew.
Chem. 1998, 110, 1323–1326; Angew. Chem. Int. Ed. 1998, 37,
1258–1261.
[75] J. T. Lenthall, K. M. Anderson, S. J. Smith, J. W. Steed, Cryst.
Growth Des. 2007, 7, 1858–1862.
[76] D. Griffiths, R. Hull, T. P. Seden, J. Chem. Soc. Perkin Trans. 1
1980, 1240–1244.
[77] N. B. Ambati, V. Babu, V. Anand, P. Hanumanthu, Synth.
Commun. 1999, 29, 289–294.
[78] S. J. Dickson, M. J. Paterson, C. E. Willans, K. M. Anderson, J. W.
Steed, Chem. Eur. J. 2008, 14, 7296–7305.
[79] S. J. Dickson, S. C. G. Biagini, J. W. Steed, Chem. Commun. 2007,
4955–4957.
[80] L. Ion, D. Morales, J. Pꢉrez, L. Riera, V. Riera, R. A. Kowenicki,
M. McPartlin, Chem. Commun. 2006, 91–93.
[81] M. A. Bennett, A. K. Smith, J. Chem. Soc. Dalton Trans. 1974,
233–241.
[82] M. Poyatos, A. Maisse-Francois, S. Bellemin-Laponnaz, E. Peris,
L. H. Gade, J. Organomet. Chem. 2006, 691, 2713–2720.
[83] S. K. Mandal, A. R. Chakravarty, J. Organomet. Chem. 1991, 417,
C59–C62.
[84] F. H. Allen, O. Kennard, Chem. Des. Autom. News 1993, 8, 31.
[85] CSD version 5.31+2 updates.
[86] J. Bernstein, R. E. Davis, L. Shimoni, N.-L. Chang, Angew. Chem.
1995, 107, 1689–1708; Angew. Chem. Int. Ed. Engl. 1995, 34, 1555–
1573.
[93] J. Marek, P. Kopel, Z. Travnicek, Acta Crystallogr. Sect. C 2003, 59,
m558–m560.
[94] W. Henderson, C. E. F. Rickard, Inorg. Chim. Acta 2003, 343, 74–
78.
[95] W. Henderson, B. K. Nicholson, E. R. T. Tiekink, Inorg. Chim.
Acta 2006, 359, 204–214.
[96] M. Lipowska, L. Hansen, A. Taylor, L. G. Marzilli, Inorg. Chem.
1996, 35, 4484–4489.
[97] M. Lipowska, B. L. Hayes, L. Hansen, A. Taylor, L. G. Marzilli,
Inorg. Chem. 1996, 35, 4227–4231.
[98] C. Bilton, J. A. K. Howard, N. N. L. Madhavi, A. Nangia, G. R. De-
siraju, F. H. Allen, C. C. Wilson, Chem. Commun. 1999, 1675–
1676.
[99] J. W. Steed, CrystEngComm 2003, 5, 169–179.
[100] I. G. Dance, Polyhedron 1986, 5, 1037–1104.
[101] G. Belchem, J. W. Steed, D. A. Tocher, J. Chem. Soc. Dalton Trans.
1994, 1949–1962.
[102] A. D. Burrows, M. D. Coleman, M. F. Mahon, Polyhedron 1999, 18,
2665–2671.
[103] J. Huang, R. L. Ostrander, A. L. Rheingold, M. A. Walters, Inorg.
Chem. 1995, 34, 1090–1093.
[104] R. D. Adams, M. P. Pompeo, J. H. Yamamoto, Organometallics
1993, 12, 951–954.
[105] J. W. Kang, K. Moseley, P. M. Maitlis, J. Am. Chem. Soc. 1969, 91,
5970.
[106] M. R. Churchill, S. A. Julis, Inorg. Chem. 1977, 16, 1488–1494.
[107] P. Gans, HypNMR 2006, University of Leeds, Leeds, 2006.
[108] C. Frassineti, S. Ghelli, P. Gans, A. Sabatini, M. S. Moruzzi, A.
Vacca, Anal. Biochem. 1995, 231, 374–382.
[109] S. J. Brooks, P. R. Edwards, P. A. Gale, M. E. Light, New J. Chem.
2006, 30, 65–70.
[110] S. J. Brooks, P. A. Gale, M. E. Light, CrystEngComm 2005, 7, 586–
591.
[111] Y. Tobe, S. Sasaki, M. Mizuno, K. Hirose, K. Naemura, J. Org.
Chem. 1998, 63, 7481–7489.
[87] D. R. Turner, B. Smith, A. E. Goeta, I. R. Evans, D. A. Tocher,
J. A. K. Howard, J. W. Steed, CrystEngComm 2004, 6, 633–641.
[88] W. Henderson, B. K. Nicholson, M. B. Dinger, R. L. Bennett,
Inorg. Chim. Acta 2002, 338, 210–218.
[89] S. D. Robinson, A. Sahajpal, J. W. Steed, Inorg. Chim. Acta 2000,
306, 205–210.
[90] W. Henderson, R. D. W. Kemmitt, S. Mason, M. R. Moore, J. Faw-
cett, D. R. Russell, J. Chem. Soc. Dalton Trans. 1992, 59–66.
[91] S. Okeya, Y. Fujiwara, S. Kawashima, Y. Hayashi, K. Isobe, Y. Na-
kamura, H. Shimomura, Y. Kushi, Chem. Lett. 1992, 1823–1826.
[112] R. A. Walton, Spectrochim. Acta 1965, 21, 1795–1801.
[113] SHELXS-97, G. M. Sheldrick, University of Gçttingen (Germany),
1997.
[114] SHELXL-97, G. M. Sheldrick, University of Gçttingen (Germany),
1997.
[115] J. L. Atwood, L. J. Barbour, Cryst. Growth Des. 2003, 3, 3–8.
[116] L. J. Barbour, J. Supramol. Chem. 2001, 1, 189–191.
Received: May 18, 2010
Published online: August 16, 2010
Chem. Eur. J. 2010, 16, 10818 – 10831
ꢀ 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
10831