Iron(ii) template synthesis of benzannulated triphospha- and triarsamacrocycles

Article abstract of DOI:10.1039/c0dt01724h

Nine-membered 1,4,7-triphospha- and triarsamacrocycles with unsaturated benzo-backbones have been prepared using the [Cp^RFe]⁺ unit as a template. The cyclisation involves the attack of a coordinated phosphide (or arsenide) nucleophil

Full text of DOI:10.1039/c0dt01724h

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PAPER
Iron(II) template synthesis of benzannulated triphospha- and
triarsamacrocycles†
Thomas Albers,a Julia Baker (nee´ Johnstone),a Simon J. Coles,b Peter G. Edwards,*a Benson Kariukia and
Paul D. Newmana
Received 8th December 2010, Accepted 27th June 2011
DOI: 10.1039/c0dt01724h
Nine-membered 1,4,7-triphospha- and triarsamacrocycles with unsaturated benzo-backbones have
been prepared using the [CpRFe]+ unit as a template. The cyclisation involves the attack of a coordinated
phosphide (or arsenide) nucleophile at an activated, electrophilic ortho-fluorophenyl substituent on a
neighbouring pnictide donor. The macrocycle assembly is of the 2 + 1 type where two new chelate rings
are formed from appropriately derivatised bidentate and monodentate phosphines/arsines. Both
[(h -C5H5)Fe]+ and [(h -C5Me5)Fe]+ may be employed for the cyclisation with higher yields generally
being observed with the unsubstituted Cp. All new compounds have been characterised by
spectroscopic and analytical methods including the single-crystal X-ray structure determination of
5
5
5
5
[(h -C5H5)Fe(tribenzo-9aneP3-Ph,PhF )]+, 3a, and [(h -C5H5)Fe(tribenzo-9aneAs3-Ph,PhF )]+, 5, as the
2
2
tetraphenylborate salts. The crystal structures are isomorphous and show the unique conformation of
these new macrocycles with a ‘cup shaped’ cavity formed by the rigid benzo-backbones. The 9aneAs3
derivative is the first example of a nine-membered triarsamacrocycle.
saturated triazamacrocycles, but more recently includes one, or
Introduction
two, unsaturated (benzo) backbones.3 We have shown that the
use of iron cyclopentadienyl piano-stool complexes as templates
for the formation of triphosphorus macrocycles is very versatile
and it was of interest to see if this approach can be extended
to the preparation of macrocycles with fully benzannulated
backbones.
Nitrogen macrocycles having rigid unsaturated conjugated or
aromatic hydrocarbon backbones are well known in biological sys-
tems. Part of the reason for their presence in living systems derives
from the exceptional stability of metal complexes of ligands such
as porphyrins, phthalocyanines and corrins. Needless to say the
coordination chemistry and properties of these systems have been
studied extensively for decades. Rather surprisingly, the chemistry
of the related triazamacrocycle, 1,4,7-triaza-tribenzocyclonane,
has not been explored; its preparation only recently being reported
in patent literature.1 The absence of studies of 1,4,7-triaza-
tribenzocyclonane from the literature contrasts starkly with the
large volume of published material on the saturated analogues
(i.e. TACN and derivatives).
We are interested in phosphorus macrocyclic ligands, par-
ticularly those that are suitable for facially capping a metal
coordination environment as they should lead to kinetically
robust complexes, but with remaining cis reactions sites. Both
of these features should be of value in developing reactivity in
applications such as catalysis. In this context, we have synthesised
a series of such ligands by template methods.2 These have
mostly been the direct analogues of TACN or of the larger ring
Previous macrocyclisation methodology has been based upon
pseudo-Michael type additions of co-ordinated primary diphos-
phines with co-ordinated di- or trialkenyl phosphines2a,b,d,e or
radical catalysed hydrophosphinations,2f neither of which is
appropriate for the formation of triphosphamacrocycles with
benzannulated backbones. A more amenable route is that based
upon an intramolecular nucleophilic attack of a metal-bound
phosphide at an electrophilic aromatic carbon.3b This synthetic
method involves ortho-fluorophenyl substituents attached to a
mono- or bis-phosphine fragment ligand with the necessary
activation of the ortho C–F bond being promoted by the inductive
effect of the metal centre.4,5 We have previously established this
synthetic approach in the formation of 9aneP3 macrocycles with
one or two benzo chelates,3b and more recently the first carbene-
phosphine mixed donor P2CNHC macrocycle.6a Subsequently, Hahn
and co-workers have shown this method to work on the same
Fe template system.6b We report here the extension to the
fully benzannulated 9aneP3 system to complete the homolep-
tic series. In addition we have used the same methodology
to prepare the triarsenic derivative which represents a unique
class as no 9-membered triarsamacrocycle has been reported
previously.
aSchool of Chemistry, Cardiff University, Cardiff, UK, CF10 3AT. E-mail:
edwardspg@cardiff.ac.uk; Fax: +44 029 20870464; Tel: +44 029 20874083
bSchool of Chemistry, University of Southampton, Highfield, Southampton,
UK, SO17 1BJ
† CCDC reference numbers 804159–804160. For crystallographic data in
CIF or other electronic format, see DOI: 10.1039/c0dt01724h
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where the reaction is promoted by the addition of catalytic
Results and discussion
5
quantities of base, our synthesis of [(h -C5H5)Fe(dibenzo-9aneP3-
Ph,PhF )]+ required at least a stoichiometric amount of base to
Synthesis of tritertiary tribenzannulated 9aneP3 macrocycles
2
quench the released HF and ensure a nearly quantitative yield of
the desired compound. This high yield contrasts with the related
It is well-known that 2-fluoroaryl groups are susceptible to
nucleophilic attack if an electron-withdrawing group is present
at the 1-position. In 2-fluoroarylphosphine ligands coordinated to
transition metals, the metal is expected to be electron-withdrawing
(a property likely to be enhanced in cationic complexes such as
the Cp-iron template herein) and so should activate the fluoride-
bearing carbons allowing substitution of fluoride by appropriate
nucleophiles (Scheme 1).
5
synthesis of the saturated [(h -C5H5)Fe(9aneP3-H2,C2H3)]+ com-
plex where only poor yields were observed with the unmodified Cp
unit. The Michael-type ring closure used to prepare the saturated
macrocycles was found to be much more efficient when peripheral
groups were present on the Cp ligand. The greater efficacy of
the unsubstituted Cp template in the current methodology may
be attributed to beneficial features of the dehydrofluorinative
mechanism including a prior electrostatic attraction between the
fluoride and the acidic proton on the primary phosphine leading
to increased acidity of the P–H and pre-organising the fragments
to favour macrocycle formation.
The precursor complex 1a was obtained as an air-sensitive red
1
powder in very good yield (94%). The 31P{ H} NMR spectrum
consists of a triplet at 92.5 ppm (3JP–F = 36.0 Hz) which is shifted
downfield with respect to the free di-phosphine ligand (-32.6 ppm)
and indicative of co-ordination to the metal ion. In addition to
Scheme 1
1
the expected aromatic peaks (7.70–6.90 ppm) in the H NMR
An advantage of the Cp-iron template is that it supports
base deprotonation of coordinated primary and secondary phos-
phines to form coordinated phosphido functions that remain
nucleophilic (as the Fe atom is an 18e- centre, p-base be-
haviour of the ligand is suppressed). The viability of this ap-
proach has been established and we have used such reactions
to prepare a dibenzotriphosphamacrocycle.3b Extension of this
methodology to the preparation of tribenzotriphosphamacrocy-
cles is straightforward requiring only the use of 1,2-bis{di(2-
fluorophenyl)phosphino}benzene instead of the ethane derivative
(Scheme 2). The cyclisation requires a base to promote initial
deprotonation of the primary phosphine and the resulting nucle-
ophilic attack at the ortho position of the fluorophenyl ring. This
mechanism relates to the work of Saunders4,5 who observed C–C
bond formation following the attack of a nucleophilic methylene
carbon derived from one of the peripheral methyls of coordinated
Cp* at the ortho position of a pentafluorophenyl moiety attached
to a co-ordinated diphosphine. Unlike the system of Saunders
spectrum, a broadened singlet at 3.96 ppm due to the Cp fragment
1
is observed. The 13C{ H} NMR spectrum shows peaks due to
the methyl protons of the acetonitrile ligand at dC 2.8 ppm,
the Cp group at dC 81.5 ppm and resonances for the aromatic
carbons amassed between 123.2 and 133.9 ppm. A characteristic
1
doublet is observed at 165.0 ppm (1JC–F = 242.9 Hz) in the 13C{ H}
NMR spectrum of 1a which can be assigned to the fluorine-
bearing ortho-carbon. The 19F NMR spectrum shows a singlet at
-98.0 ppm suggesting time-averaged equivalence of all the flu-
orophenyl groups. The CN stretch for the co-ordinated ace-
tonitrile appears in the infrared spectrum at 2266 cm-1. Ad-
dition of phenylphosphine and subsequent heating to 60 ◦C
in ClCH2CH2Cl gave the complex 2a as a yellow, slightly air-
1
sensitive powder in excellent yield (93%). The 31P{ H} NMR
spectrum of 2a shows an AX2 pattern at 84.6 (2JP–P = 51.0 Hz)
and 12.1 ppm for the bidentate and monodentate phosphines,
respectively. The most distinctive feature of the 1H NMR
1
spectrum is the large doublet at 4.38 ppm with JP–H of
347 Hz for the PH hydrogens of the coordinated phenylphos-
phine. The 19F NMR spectrum showed a singlet at -98.0 ppm
representing the co-ordinated bidentate phosphine.
The addition of base to a solution of the precursor complex
2a led to the formation of the complete macrocycle and complex
3a was isolated as an air-stable yellow powder in good yield. The
1
31P{ H} NMR spectrum of 3a shows the usual downfield shift in
2
dP of ~120 ppm (t, JP–P = 32.8 Hz) for the phenylphosphine P-
atom, consistent with its incorporation into the macrocycle ring
(this is expected as the phosphorus is a constituent of two chelate
rings as opposed to being a simple monodentate donor) and a
broadened doublet for the fluorophenylphosphines at 127.5 ppm.
Attempts to resolve any fine coupling for the PPhF phosphines in
1
3a by recording the 31P{ H} NMR spectrum at low temperature
led instead to more complicated resonance patterns. Inspection of
the 19F NMR spectrum, which is a broad singlet at RT, at these low
temperatures revealed the presence of four distinct resonances, two
of which were of approximately equal intensity. This is likely the
result of restricted rotation about the P–PhF bond at these lower
Scheme 2
9526 | Dalton Trans., 2011, 40, 9525–9532
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˚
temperatures resulting in all possible rotamers being observed and
where the rotation is sufficiently fast at ambient temperatures to
lead to a time-averaged spectrum. The 1H and 13C NMR spectra
are largely uninformative, the only characteristic features being
in Fig. 1 for clarity. The value of 2.149(1) A for the average Fe–
P bond length is appreciably smaller than that measured for the
dibenzannulated example where the Fe–P bonds averaged 2.164(1)
◦
˚
A. The P–Fe–P bond angles of 86.51(5), 86.49(5) and 86.75(5) are
all compressed from the ideal 90◦ as a consequence of the rigid
nature of the 5-membered rings and, indeed, the macrocycle as a
whole, and are comparable with those for the reported dibenzo-
9aneP3 example. Slightly smaller angles have been reported for
the saturated Fe(II) systems but direct comparison is not possible
because these literature examples have bulkier CpR ligands that
influence the P–Fe–P angles. The distance between the centroid of
the presence of the doublet of doublets at dC 165.3 (1JC–F
=
252.9 Hz, 2JC–P = 4.8 Hz) ppm.
Fine needle like yellow crystals of 3a suitable for X-ray
diffraction were obtained by anion exchange with NaB(C6H5)4
and subsequent recrystallisation from acetonitrile at -37 ◦C. Two
views of the crystal structure are shown in Fig. 1. The upper
view illustrates the relatively regular ‘piano-stool’ arrangement
of ligands, whereas the lower view emphasises the distinctive
toroidal cavity that is made by the orientation of the three benzo
groups and which might be suitable as an anion binding space.
The fluorines occupy disordered positions with the two fluorines
equally distributed between all three observed positions and the
structure was refined with partial (2/3) occupancies. The Cp ring
is also rotationally disordered, as is common in half-sandwich
compounds of this type; only one position of the Cp ring is shown
˚
the Cp ring and the Fe atom is 1.535 A and the distance between
the Fe atom and the centroid of the P3 ring is 1.313 A.
˚
The analogous Cp* tribenzannulated complex can also be
synthesised by the same synthetic route. The initial precursor
complex [(h -C5Me5)Fe{(PhF)2PC6H4P(PhF)2}(MeCN)]BF4, 2b,
5
was synthesised as a red air-sensitive, THF soluble powder, in
very good yield (94%). Characteristic peaks at 1.63 (Cp* methyls)
and 2.19 ppm (CH3CN) are seen in the 1H NMR spectrum along
with multiplets in the aromatic region between 6.69 and 7.86 ppm.
Otherwise the remaining NMR data reflect closely those observed
for the analogous Cp compound. A broad singlet is seen at
90.1 ppm in the 31P{ H} NMR spectrum and the ortho-
1
fluorophenyl groups appear as a singlet at -99.6 ppm in the 19F
NMR spectrum. The subsequent cyclisation chemistry proceeds
in the same manner as described for the Cp derivative and the
resulting complexes 2b and 3b show the same general spectroscopic
features as those observed for the Cp derivatives above.
The Cp* dibenzannulated triphosphorus macrocycle could not
be synthesised as the addition of base resulted in immediate
decomposition, possibly as a result of the methyl groups attached
to the Cp* attacking the reactive ortho-fluorophenyl rings.
Synthesis of disecondary, monotertiary tribenzannulated 9aneP3
macrocycles
Although the synthesis of the tritertiary P3 macrocycles high-
lighted above gave good yields of the final products, these products
could not be further functionalised readily to allow access to
a range of different macrocyclic compounds. In addition, the
necessary 1,2-bis{di(2-fluorophenyl)phosphino}benzene precur-
sor was in itself not easy to access on a large scale. Our desire to
prepare a number of different derivatives of the tribenzannulated
9aneP3 systems required a synthetic approach that produced
complexes with a functionality or functionalities that could be
easily converted into other groups by standard synthetic proce-
dures. This flexibility can be realised if one or more P–H groups
are present in the initially formed macrocyclic product. Thus,
the synthetic procedure highlighted in Scheme 3 was identified
as being a more flexible approach to these tribenzannulated
systems, this methodology differs from that in Scheme 2 by using
the bidentate primary phosphine, 1,2-bis-phosphinobenzene, and
a monodentate tertiary phosphine bearing the 2-fluorophenyl
substituents. This modification has the synthetic advantage that
P(PhF)3 is more easily prepared on a multigram scale than the
(PhF)2PC6H4P(PhF)2 species which is itself prepared from 1,2-bis-
phosphinobenzene.
Fig. 1 Two ORTEP views of the cation 3a. Thermal ellipsoids are
drawn at the 30% occupancy level. Selected bond lengths (A): Fe(1)–P(1)
2.152(1); Fe(1)–P(2) 2.154(1); Fe(1)–P(3) 2.142(1). Selected bond angles
(deg): P(1)–Fe(1)–P(2) 86.51(5), P(1)–Fe(1)–P(3) 86.75(5), P(2)–Fe(1)–P(3)
86.49(5). Hydrogen atoms, the Ph4B- anion and four molecules of
acetonitrile of crystallisation are omitted for clarity.
˚
The substitution of the acetonitrile in the precursor complex
5
[(h -C5H5)Fe(H2PC6H4PH2)(CH3CN)]PF6 by P(PhF)3 is achieved
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phosphorus in coordination chemistry and is rare in macrocyclic
systems; there are no reports of homoleptic 9aneAs3 species.
The necessary (PhF)2AsC6H4As(PhF)2 and As(PhF)3 precursor
ligands are readily prepared in the same fashion as for the
5
phosphorus analogues. Following method 1, the complex [(h -
C5H5)Fe{(PhF)2AsC6H4As(PhF)2}(CH3CN)]+ (1c) is prepared by
the same procedure that provided the P-analogue and was isolated
as a purple solid. The complex is somewhat unstable in solution
especially when exposed to air but appears indefinitely stable in the
solid-state in the absence of air. The 19F NMR spectrum showed a
1
characteristic singlet at -99.8 ppm. The 13C{ H} NMR spectrum
showed a singlet at 2.6 ppm representing the co-ordinated
acetonitrile, a broad singlet for the Cp carbons at 76.4 ppm and
a characteristic doublet for the ortho-fluoro carbon at 165.0 ppm
(1JC–F = 241.9 Hz). A characteristic peak at 2262 cm-1 is seen for the
co-ordinated acetonitrile in the infrared spectrum. Substitution of
the MeCN ligand with phenylphosphine is straightforward with
complex 3c being obtained as an orange powder in good yield. The
nature of the complex is confirmed by NMR spectroscopy with
Scheme 3
by the usual procedure to give 6a as a yellow, slightly air-
sensitive powder in good yield (82%). Coordination of the triflu-
ororarylphosphine is confirmed by the 31P{ H} NMR spectrum
1
which shows a broad singlet at 22.0 ppm in addition to the singlet
at 16.0 ppm for the coordinated bisphosphinobenzene. Although
no coupling can be resolved as a consequence of the broad nature
1
singlets being observed in the 31P{ H} and 19F NMR spectra at
of the 31P{ H} resonance, it is clear that the magnitude of any 3JP–F
1
-3.0 and -101.4 ppm, respectively. All other spectroscopic features
are very similar to the related phosphorus systems which have
already been discussed.
coupling is greatly reduced compared to that seen in the spectrum
of the uncoordinated ligand (dP -42.1 ppm, 3JP–F = 56.6 Hz). This is
emphasised in the 19F NMR spectrum of 6a which shows a singlet
Use of phenylarsine instead of phenylphosphine with the
1
at -97.9 ppm. The H NMR spectrum shows a broad singlet at
3.61 ppm due to the Cp resonances and complex multiplets from
5
[(h -C5H5)Fe{(PhF)2AsC6H4As(PhF)2}(CH3CN)]+ precursor gave
5
the complex [(h -C5H5)Fe{(PhF)2AsC6H4As(PhF)2}(PhAsH2)]+ (4)
6.94–7.39 ppm which can be assigned to the aromatic protons. The
and ultimately the novel triarsamacrocycle complex 5, following
reaction with base, as an orange solid. Complex 4 was charac-
terised by an upfield shift in the 19F NMR spectrum to -101.5 ppm
upon replacement of the coordinated acetonitrile by phenylarsine.
13C{ H} NMR spectrum shows a doublet of doublets at 165.0 ppm
1
(1JC–F = 285.3 Hz, JC–P = 5.1 Hz) in addition to other aromatic
2
resonances consistent with the formulation. Cyclisation to 7a
was promoted by excess triethylamine and could be conveniently
1
The 13C{ H} NMR spectrum showed the characteristic doublet
monitored by 31P{ H} NMR spectroscopy. After 2 h at reflux, a
1
(assigned to the carbon bearing the fluorine) at 164.9 ppm
(1JC–F = 239.8 Hz). The 19F NMR spectrum of the macrocycle
complex 5 shows a singlet at -100.1 ppm at room temperature
which splits into 3 separate resonances when the sample is
cooled to -80 ◦C. This reflects the presence of rotamers at low
temperature as proposed for the 9aneP3 analogue above. As stated,
the triarsenic macrocycle is unique. The only other example of
a triarsenic macrocycle was synthesised by Kyba under high
dilution conditions where he was able to obtain the non-templated
macrocycle as a mixture of isomers.7 Our synthesis occurs in good
yield (73%) but efforts to liberate the free macrocycle has thus far
proved unsuccessful.
triplet at 89.1 ppm (2JP–P = 35.7 Hz) was observed in the 31P{ H}
1
NMR spectrum in addition to a complex multiplet at 66.5 ppm;
this pattern represents the partially formed macrocycle where one
new chelate ring is present. Continued heating led to slow loss
of this intermediate and the growth of peaks for complex 7a as
a doublet (2JP–P = 35.7 Hz) and a multiplet at 89.1 and 120.2
ppm respectively. The 19F NMR spectrum showed a singlet at
-101.8 ppm and resonances corresponding to aromatic protons
(6.95–7.71 ppm) and the Cp hydrogens (3.73 ppm) were the only
peaks seen in the H NMR spectrum while the 13C{ H} NMR
1
1
spectrum shows a slightly broadened doublet at 165.0 ppm (1JC–F
=
286.0 Hz), with unresolved 2JC–P coupling. The molecular ion was
observed in the mass spectrum at 779.6 amu. The Cp* tribenzannu-
lated triphosphorus macrocycle (7b) can be synthesised similarly
Fine needle like yellow crystals of 5 suitable for X-ray diffraction
were obtained after anion exchange with NaBPh4 and subsequent
recrystallisation from acetonitrile at -37 ◦C. Two views of the
cation (Fig. 2) are shown to illustrate the similarity between the
triphosphorus and triarsenic analogues of this type of macrocycle;
the structures are isomorphous. Again, the two fluorine atoms are
disordered between three positions and the Cp ring is rotationally
disordered, as was observed for the phosphine analogue. Again,
for clarity, only one position of the Cp ring is shown in Fig.
2. The fluorines were again successfully refined with partial
occupancies (2/3). The gross structure resembles closely that of the
triphosphorus macrocycle with the only significant differences
from the [(h -C5Me5)Fe(H2PC6H4PH2)(CH3CN)]+ complex and
5
isolated as a yellow air-stable powder. All spectroscopic features
are as expected and are given in the experimental section.
Dibenzannulated 9aneP3 macrocycles are also accessible by this
second method when the 1,2-bis(phosphino)benzene is replaced
with 1,2-bis(phosphino)ethane, albeit in somewhat lower yields
than for the tribenzannulated analogue.
Synthesis of tribenzannulated 9anePAs2 and 9aneAs3 macrocycles
˚
Both of the methods developed above should be amenable to
extension to the 9anePAs2 and 9aneAs3 macrocycles by simple
replacement of the P-containing synthons with the analogous
arsenic ligands. Arsenic is not as common a donor type as
being the increased average Fe–As bond length of 2.223(1) A
compared to the Fe–P lengths in the P3 analogue (average
2.149(1)); and the average As–Fe–As angle in 5 (86.97(5)◦) is also
slightly larger than the average P–Fe–P angle in 3a (86.53(5)◦). The
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suggest the presence of a cavity that may be able to accommodate
various anions.
For reasons unknown, the analogous bulkier Cp*Fe+ system
was a poor template for the formation of the 9aneAs3 macrocycle.
In addition, application of the second methodology for the
synthesis of disecondary monotertiary 9aneAs3 macrocycles was
also unsuccessful; attempts to coordinate 1,2-bis(arsino)benzene
to either the Cp or Cp* iron templates lead to decomposition
under the reaction conditions; although initial colour changes
were observed, the solutions rapidly decomposed to intractable
brown materials that were not amenable to further reaction.
Experimental
Methods and materials
All synthetic procedures and manipulations were performed under
dry argon or nitrogen using standard Schlenk line techniques.
All solvents were freshly distilled from sodium (toluene),
sodium/benzophenone (THF) or calcium hydride (acetonitrile,
methanol and dichloromethane) under nitrogen before use. All
other chemicals were obtained commercially and used as received.
The 31P NMR spectra were recorded on a JEOL Eclipse 300 MHz
spectrometer operating at 121.7 MHz, and referenced to 85%
1
H3PO4 (d = 0 ppm). H and 13C NMR spectra were obtained
using a Bruker 500 MHz spectrometer, operating at 500.0 and
125.8 MHz, respectively, and referenced to tetramethylsilane
(d = 0 ppm). Unless stated otherwise, infrared spectra were
recorded as nujol mulls on a Jasco FTIR spectrometer. Mass
spectra were obtained using a Waters LCT Premier XE mass
spectrometer. Elemental analyses were performed by Medac
Ltd,
UK.12
1,2-Bis{di(2-fluorophenyl)phosphino}benzene,
Fig. 2 Two ORTEP views of the cation 5. Thermal ellipsoids are drawn
1,2-bis{di(2-fluorophenyl)phosphino}ethane, and 1,2-bis{di(2-
fluorophenyl)arsino}benzene were prepared using literature
methods.13 Other starting materials that had previously been
prepared which are utilised in the experimental procedure
˚
at the 30% occupancy level. Selected bond lengths (A): Fe(1)–As(1)
2.2340(14); Fe(1)–As(2) 2.2252(14); Fe(1)–As(3) 2.2100(14). Selected bond
angles (deg): As(1)–Fe(1)–As(2) 86.81(5), As(2)–Fe(1)–As(3) 86.88(5),
As(1)–Fe(1)–As(3) 87.23(5). Hydrogen atoms, the Ph4B- anion and four
molecules of acetonitrile of crystallisation are omitted for clarity.
5
5
include [(h -C5H5)Fe(H2PC6H4PH2)CH3CN]PF6, and [(h -
C5Me5)Fe(H2PC6H4PH2)CH3CN]PF6.2a
Fe–As bonds in 5 are shorter than those observed in a number of
iron(II) systems containing monodentate and bidentate arsines,
for example the Fe–As bond lengths are 2.235(1), 2.326(2), and
Syntheses
[(g5-C5H5)Fe{(PhF)2PC6H4P(PhF)2}CH3CN]PF6, 1a. To a so-
5
+
8
5
˚
2.3380(5) A in the complexes [(h -C5H5)Fe(diphos)(PhMeAsF)] ,
lution of [(h -C5H5)Fe(CO)2(CH3CN)]PF6 (0.36 g, 1 mmol)
5
10
[(h -C5H5)Fe(diphos)(cyc-C3AsPh)]+,9 and Fe(diars)2I2 respec-
tively. The Fe–As distance is most closely similar to the example
with the more p-acidic fluoroarsine, rather than the more s-basic
alkyl arsines; the aryl and fluoro-aryl substituents in 5 are likely
to render the ligand more similar in p-acidity to the former rather
than the latter and thus the bond distances in 5 are unexceptional.
The slightly longer Fe–pnictide bond length in 5 in comparison to
3a is also likely to be limited by the rigid structure of the ligand
which may compress these values in comparison to monodentate
and less rigid bidentate ligands. The average Fe–As bond length of
all known crystallographic structures of complexes of Fe(II) with
in THF (15 ml) was added a solution of 1,2-bis[di(2-
fluorophenyl)phosphino]benzene (0.47 g, 1 mmol) in THF (30 ml)
at room temperature. The solution was photolysed with a 100
W table top lamp for 24 h resulting in a colour change from
yellow to red. The reaction mixture was filtered through celite and
the solvent removed in vacuo. Trituration with ether gave a red
powder. Yield = 0.78 g (94%). 1H NMR (CDCl3, 400 MHz) d 6.9–
7.7 (20H, m, ArH), 3.96 (5H, s, C5H5), 2.29 (3H, s, CH3CN) ppm.
1
13C{ H} NMR (CDCl3, 100 MHz) d 165.02 (d, 1JC–F = 242.9 Hz),
123.2–133.9 (m), 115.67 (d, 1JC–P = 23.5 Hz), 81.41 (s, CH), 2.80 (s,
CH3) ppm. 31P{ H} NMR (CDCl3, 121.7 MHz): 92.5 (s br), -143.7
1
11
-
tertiary arsines is 2.366 A. The cavity size is illustrated by the
(septet, 1JP–F = 714 Hz, PF6 ) ppm. 19F NMR (CDCl3): -98.0 (s),
˚
1
-
non-bonding distances between the individual arsenic atoms; the
-73.5 (d, JF–P = 714 Hz, PF6 ) ppm. MS: 680 (M+, 60%). Anal.
Calc. for C37H28NP3F10Fe: C, 53.84; H, 3.43; N, 1.70%. Found: C,
53.2; H, 3.2; N, 1.6%.
˚
average As–As distance is 3.060 A which is again a little longer
˚
than the average P–P distance (2.948 A) in 3a. These distances
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1
[(g5-C5Me5)Fe{(PhF)2PC6H4P(PhF)2}CH3CN]BF4, 1b. To a
(m), 87.70 (s, C), 9.70 (s, CH3) ppm. 31P{ H} NMR (CDCl3,
121.7 MHz): 81.7 (s), 10.1 (s) ppm. 19F NMR (CDCl3): -98.2
(s) ppm. MS: 820 (M+, 100%). Anal. Calc. for C46H42P3F8BFe: C,
60.95; H, 4.68%. Found: C, 60.5; H, 4.7%.
5
solution of [(h -C5Me5)Fe(CO)2(CH3CN)]BF4 (1.13 g, 3 mmol)
in THF (10 ml) was added
a solution of 1,2-bis[di(2-
fluorophenyl)phosphino]benzene (1.56 g, 3 mmol) in THF (15 ml)
at room temperature. The solution was photolysed with a 100
W table top lamp for 24 h resulting in a colour change from
yellow to red. The reaction mixture was filtered through celite,
the solvent removed in vacuo and the solid triturated with ether
[(g5-C5H5)Fe{(PhF)2AsC6H4As(PhF)2}(PhPH2)]PF6,
2c. 1c
(0.88 g, 0.96 mmol) was dissolved in 1,2-dichlorobenzene (30 ml).
Phenylphosphine (0.5◦ml, 4.5 mmol) was added and the reaction
mixture heated to 60 C for 16 h until the colour changed from
dark blue to orange. The solvent was removed in vacuo and the
residue triturated with ether to give a yellow powder. Yield =
1
to give a red powder. Yield = 2.53 g (94%). H NMR (CDCl3,
400 MHz) d 6.7–7.9 (20H, m, ArH), 2.19 (3H, s, CH3CN), 1.63
1
(15H, s, C5Me5) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d 165.02
1
3
(1JC–F = 242.9, JC–P = 7.0 Hz), 123.2–133.9 (m), 118.10 (s, C),
0.86 g, (91%). H NMR (CDCl3, 400 MHz) d 6.7–7.5 (25H, m,
ArH), 4.63 (2H, d, 1JH–P = 338 Hz, PH), 3.98 (5H, s, C5H5) ppm.
115.67 (d, 1JC–P = 23.5 Hz), 87.31 (C), 9.54 (s, CH3), 3.92 (s, CH3)
13C{ H} NMR (CDCl3, 100 MHz) d 164.32 (d, 1JC–F = 243.2 Hz),
1
1
ppm. 31P{ H} NMR (CDCl3, 121.7 MHz): 90.1 (s br) ppm. 19F
1
NMR (CDCl3): -99.6 (s) ppm. MS: 751 (M+, 80%). Anal. Calc.
for C42H38NBP2F8Fe: C, 60.24; H, 4.58; N, 1.67%. Found: C, 59.9;
H, 4.4; N, 1.5%.
124.0–136.0 (m), 115.61 (d, JC–P = 23.2 Hz) 80.9 (s, CH) ppm.
31P{ H} NMR (CDCl3, 121.7 MHz): 11.8 (s), -143.7 (septet,
1
1JP–F = 714 Hz, PF6 ) ppm. 19F NMR (CDCl3): -101.4 (s), -73.5
-
(d, 1JF–P = 714 Hz, PF6 ) ppm. MS: 837 (M+, 100%). Anal. Calc.
-
[(g5-C5H5)Fe{(PhF)2AsC6H4As(PhF)2}CH3CN]PF6, 1c. To a
for C41H32P2As2F10Fe: C, 50.13; H, 3.29%. Found: C, 49.8; H,
5
solution of [(h -C5H5)Fe(p-xylene)]PF6 (0.37 g, 1 mmol) in
3.2%.
acetonitrile (15 ml) was added a solution of 1,2-bis[di(2-
fluorophenyl)arsino]benzene (1 mmol) in acetonitrile (15 ml). This
was photolysed with a 100 W table top lamp for 24 h resulting in a
colour change from yellow to dark blue. The reaction mixture was
filtered through celite, the solvent removed in vacuo and the solid
triturated with ether to give a purple-blue powder Yield = 0.87 g
(95%). 1H NMR (CDCl3, 400 MHz) d 6.7–7.5 (20H, m, ArH), 3.95
[(g5-C5H5)Fe(tribenzo-9aneP3-Ph,PhF )]PF6, 3a. Potassium
2
tert-butoxide (2 mole equivalents, 0.09 g, 0.78 mmol) was added
to a solution of 2a (0.33 g, 0.39 mmol) in THF (40 ml) and the
reaction mixture left to stir overnight. After filtering, the solvent
was removed in vacuo to give a yellow solid. Yield = 0.26 g (78%).
1H NMR (CDCl3, 400 MHz) d 7.3–7.6 (25H, m, ArH), 3.81 (5H,
1
s, C5H5) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d 163.29 (d,
1
(5H, s, C5H5), 2.29 (3H, s, CH3CN) ppm. 13C{ H} NMR (CDCl3,
1
1JC–F = 252.7 Hz), 129.9–134.7 (m), 115.34 (d, JC–P = 23.1 Hz),
100 MHz) d 164.99 (d, 1JC–F = 241.9 Hz), 125.5–136.4 (m), 121.60
1
82.13 (s, CH) ppm. 31P{ H} NMR (CDCl3, 121.7 MHz): 127.5
1
(s), 115.52 (d, JC–P = 24.1 Hz), 76.4 (s, CH), 2.60 (s, CH3) ppm.
2
2
-
19F NMR (CDCl3): -99.8 (s), -73.5 (d, 1JF–P = 714 Hz, PF6 ) ppm.
(d, JP–P = 32.8 Hz), 119.6 (t, JP–P = 32.8 Hz), -143.7 (septet,
1JP–F = 714 Hz, PF6 ) ppm. 19F NMR (CDCl3): -98.4 (s), -73.5 (d,
-
MS: 768 (M+, 100%). Anal. Calc. for C37H28NPAs2F10Fe: C, 48.66;
H, 3.10; N, 1.53%. Found: C, 48.2; H, 3.0; N, 1.6%.
1JF–P = 714 Hz, PF6 ) ppm. MS: 709 (M+, 100%). Anal. Calc. for
-
C41H30P4F8Fe: C, 57.63; H, 3.55%. Found: C, 57.5; H, 3.2%.
5
[(g5-C5H5)Fe{(PhF)2PC6H4P(PhF)2}(PhPH2)]PF6, 2a. [(h -
[(g5-C5Me5)Fe(tribenzo-9aneP3-Ph,PhF )]BF4, 3b. 2b (0.35 g,
C5H5)Fe{(PhF)2PC6H4P(PhF)2}CH3CN]PF6,
1a
(0.75
g,
2
0.39 mmol) was dissolved in THF (30 ml), and potassium tert-
butoxide (catalytic quantity) was added to the solution. The
reaction was heated to 60 ◦C for 16 h. After filtration, the solvent
was removed in vacuo to give a yellow solid. Yield = 0.23 g (78%).
1H NMR (CDCl3, 400 MHz) d 6.9–7.3 (25H, m, ArH), 1.67 (15H,
0.96 mmol) was dissolved in 1,2-dichloroethane (40 ml).
Phenylphosphine (0.5 ml) was added and the reaction mixture
heated to 60 ◦C for 6 h until the colour changed from red to
orange. The solvent was removed in vacuo and the solid residue
triturated with ether to give a yellow powder. Yield = 0.80 g (93%).
1H NMR (CDCl3, 400 MHz) d 6.8–7.6 (25H, m, ArH), 4.38 (2H,
1
s, C5Me5) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d 165.80 (d,
1
1JC–F = 324.3 Hz), 123.9–134.9 (m), 80.1 (s), 10.1 (s) ppm. 31P{ H}
1
1
d, JH–P = 331 Hz, PH), 3.81 (5H, s, C5H5) ppm. 13C{ H} NMR
NMR (CDCl3, 121.7 MHz): 117.3 (t, 2JP–P = 35.3 Hz), 111.9 (m)
ppm. 19F NMR (CDCl3): -100.9 (s) ppm. MS: 780 (M+, 100%).
Anal. Calc. for C46H40P3F6BFe: C, 63.76; H, 4.66%. Found: C,
63.2; H, 4.4%.
1
(CDCl3, 100 MHz) d 163.29 (d, JC–F = 252.7 Hz), 125.2–135.0
1
1
(m), 117.60 (d, JC–P = 23.0 Hz), 82.88 (s, CH) ppm. 31P{ H}
NMR (CDCl3, 121.7 MHz): 84.6 (d, 2JP–P = 51 Hz), 12.1 (t, 2JP–P
=
1
-
51 Hz), -143.7 (septet, JP–F = 714 Hz, PF6 ) ppm. 19F NMR
(CDCl3): -98.0 (s), -73.5 (d, 1JF–P = 714 Hz, PF6 ) ppm. MS: 749
-
[(g5-C5H5)Fe(tribenzo-9aneAs2P-Ph,PhF )]PF6, 3c. 2c (0.22 g,
(M+, 100%). Anal. Calc. for C41H32P4F10Fe: C, 55.05; H, 3.61%.
Found: C, 55.2; H, 3.2%.
2
0.22 mmol) was dissolved in THF (40 ml) and potassium tert-
butoxide (0.5 g) was added as a solid to the solution. The reaction
was left to stir overnight, filtered and the solvent removed in
vacuo to give a yellow solid. Yield = 0.15 g (73%). 1H NMR
(CDCl3, 400 MHz) d 6.9–7.7 (25H, m, ArH), 3.98 (5H, s, C5H5)
[(g5-C5Me5)Fe{(PhF)2PC6H4P(PhF)2}(PhPH2)]BF4, 2b. Phe-
nylphosphine (0.4 ml, 3.6 mmol) was added to a solution of 1b
(0.80 g, 0.96 mmol) in THF (30 ml). The reaction mixture was
heated to 60 ◦C for 24 h until the colour changed from red
to orange. The solvent was removed in vacuo and the residue
triturated with ether to give a yellow powder. Yield = 0.80 g (92%).
1H NMR (CDCl3, 400 MHz) d 6.9–7.5 (25H, m, ArH), 4.45 (2H,
1
ppm. 13C{ H} NMR (CDCl3, 100 MHz) d 128.9–135.1 (m), 82.0
1
(s) ppm. 31P{ H} NMR (CDCl3, 121.7 MHz): 134.6 (s), -143.7
-
(septet, 1JP–F = 714 Hz, PF6 ) ppm. 19F NMR (CDCl3): -100.1 (s),
-73.5 (d, 1JF–P = 714 Hz, PF6 ) ppm. MS: 797 (M+, 100%). Anal.
-
1
d, 1JH–P = 343 Hz, PH), 1.63 (15H, s, C5Me5) ppm. 13C{ H} NMR
Calc. for C41H30P2As2F8Fe: C, 52.26; H, 3.22%. Found: C, 49.8;
H, 3.2%.
1
(CDCl3, 100 MHz) d 165.85 (d, JC–F = 325.7 Hz), 124.9–135.1
9530 | Dalton Trans., 2011, 40, 9525–9532
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2
2
123.9 (t, JP–P = 27 Hz), 92.3 (t, JP–P = 27 Hz) ppm. 19F NMR
[(g5-C5H5)Fe{(PhF)2AsC6H4As(PhF)2}(PhAsH2)]PF6, 4. Phe-
nylarsine (0.8 ml, 0.96 mmol) was added to a solution of 1c
(0.88 g, 0.96 mmol) in 1,2-dichloroethane (30 ml) and the reaction
mixture heated to 60 ◦C for 6 h until the colour changed from
red to orange. The solvent was removed in vacuo and the residue
triturated with ether to give an orange powder. Yield = 0.86 g
-
(CDCl3): -101.8 (s), -73.5 (d, 1JF–P = 714 Hz, PF6 ) ppm. MS: 539
(M+, 100%). Anal. Calc. for C29H23P4F7Fe: C, 50.90; H, 3.39%.
Found: C, 50.4; H, 3.4%.
[(g5-C5Me5)Fe(tribenzo-9aneP3-H2,PhF)]BF4,
amine (0.5 ml, 5 mmol) was added to a solution of 6b (0.59 g,
0.80 mmol) in THF (30 ml) and the reaction mixture heated to
60 ◦C for 8 h. The solvent was removed in vacuo to give a yellow
7b. Triethyl-
1
(86%). H NMR (CDCl3, 400 MHz) d 6.8–7.6 (25H, m, ArH),
1
4.01 (5H, s, C5H5) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d
1
164.91 (d, JC–F = 239.8 Hz), 128.9–135.1 (m), 83.4 (s) ppm. 19F
1
powder. Yield = 0.50 g (90%). H NMR (CDCl3, 400 MHz) d
NMR (CDCl3): -101.5 (s) ppm. MS: 881 (M+, 100%). Anal. Calc.
6.8–7.4 (16H, m, ArH), 1.70 (15H, s, C5Me5) ppm. 13C{ H} NMR
1
for C41H32PAs3F10Fe: C, 47.98; H, 3.15%. Found: C, 47.8; H, 2.9%.
1
(CDCl3, 100 MHz) d 164.71 (d, JC–F = 234.3 Hz), 121.5–133.8
(m), 115.54 (d, JC–P = 23.0 Hz) ppm. 31P{ H} NMR (CDCl3):
115.1 (s), 108.0 (m) ppm. 19F NMR (CDCl3): -103.4 (s) ppm.
MS: 609 (M+, 100%). Anal. Calc. for C34H33P3F5BFe: C, 58.65;
H, 4.79%. Found: C, 58.5; H, 4.5%.
1
1
[(g5-C5H5)Fe(tribenzo-9aneAs3-Ph,PhF )]PF6, 5. 4 (0.22 g, 0.22
2
mmol) was dissolved in THF (40 ml), and potassium tert-butoxide
(0.50 g) was added to the solution. The reaction was left to stir
overnight and filtered. The solvent was removed in vacuo to give
a yellow solid. Yield = 0.16 g (73%). 1H NMR (CDCl3, 400 MHz)
1
d 6.9–7.8 (25H, m, ArH), 3.98 (5H, s, C5H5) ppm. 13C{ H} NMR
Crystallography
1
(CDCl3, 100 MHz) d 164.92 (d, JC–F = 240.0 Hz), 130.1–132.4
The crystal structures reported herein were obtained on the
tetraphenylborate salts of the complexes after anion exchange
of the PF6 salts with NaBPh4 in acetonitrile from which both
compounds crystallise with four molecules of acetonitrile of
crystallisation in the unit cell. Anions and solvent molecules are
omitted from the figures for clarity; there are no chemically signif-
icant intermolecular interactions. Data collection was carried out
on a Bruker-Nonius Kappa CCD diffractometer using graphite
(m), 78.1 (s) ppm. 19F NMR (CDCl3): -101.5 (s), -73.5 (d, 1JF–P
=
714 Hz, PF6 ) ppm. MS: 822 (M+ - F, 100%). Anal. Calc. for
-
-
C41H30PAs3F8Fe: C, 49.93; H, 3.07%. Found: C, 49.2; H, 2.9%.
[(g5-C5H5)Fe(H2PC6H4PH2){(P(PhF)3}]PF6, 6a. To
a so-
5
lution of [(h -C5H5)Fe(H2PC2H4PH2)(CH3CN)]PF6 (0.43 g,
0.96 mmol) in acetonitrile (35 ml) was added tris(ortho-
fluorophenyl)phosphine (0.32 g, 1 mmol) and the reaction mixture
heated to 60 ◦C for 18 h whereupon a colour change from red
to yellow was observed. The solvent was removed in vacuo and
the resultant solid triturated with ether to give a yellow powder.
Yield = 0.31 g (46%). 1H NMR (CDCl3, 400 MHz) d 6.9–7.4 (16H,
˚
monochromated Mo-Ka radiation (l(Mo-Ka) = 0.71073 A). The
instrument was equipped with an Oxford Cryosystems cooling
apparatus. Data collection and cell refinement were carried out
using COLLECT14 and HKL SCALEPACK.15 Data reduction
was applied using HKL DENZO and SCALEPACK.16 The
structures were solved using direct methods (Sir92)16 and refined
with SHELX-97.17 Absorption corrections were performed using
SORTAV.18 All non-hydrogen atoms were refined anisotropically,
while the hydrogen atoms were inserted in idealised positions with
Uiso set at 1.2 or 1.5 times the Ueq of the parent atom. In the final
cycles of refinement, a weighting scheme that gave a relatively
flat analysis of variance was introduced and refinement continued
until convergence was reached. In both structures, the carbon
positions in the cyclopentadienyl rings and the fluorine positions
are disordered. For both 3a and 5, the cyclopentadienyl rings were
modeled over two positions related by an ~36◦ rotation, each with
50% occupancy. The two F atoms are distributed over three sites
1
m, ArH), 4.35 (5H, s, C5H5), 3.44 (4H, d, JH–P = 379 Hz) ppm.
1
13C{ H} NMR (CDCl3, 100 MHz) d 165.18 (d, 1JC–F = 285.3 Hz),
1
2
120–135 (m), 80.6 ppm. 31P{ H} NMR (CDCl3): 60.8 (t, JP–P
=
57 Hz), 11.5 (dq, JP–P = 57 Hz, JP–F = 16 Hz) ppm. 19F NMR
2
5
(CDCl3): -97.9 (s), -73.5 (d, 1JF–P = 714 Hz, PF6 ) ppm. MS: 579
-
(M+, 100%). Anal. Calc. for C29H25P4F9Fe: C, 48.09; H, 3.49%.
Found: C, 47.5; H, 3.4%.
5
[(g5-C5Me5)Fe(H2PC6H4PH2){(P(PhF)3}]BF4,6b. [(h -C5Me5)-
Fe(H2PC6H4PH2)(CH3CN)]BF4 (0.45 g, 0.98 mmol) was dissolved
in acetonitrile (30 ml) and tris(ortho-fluorophenyl)phosphine (1.6
g, 5 mmol) added thereto. The reaction mixture was heated to 60
◦C for 10 h whereupon the colour changed from red to yellow. The
solvent was removed in vacuo to give a yellow powder. Yield = 0.59
g (82%). 1H NMR (CDCl3, 400 MHz) d 6.7–7.4 (16H, m, ArH),
2
in both structures. For 3a, an occupancy of /3 was used for all
sites whereas for 5, the occupancies refined to 0.61(2), 0.76(2) and
0.63(2). Pertinent data are collected in Table 1.
1
1.72 (15H, s, C5Me5) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d
1
2
164.00 (dd, JC–F = 234.3 Hz, JC–P = 6.4 Hz), 121.5–133.8 (m),
115.24 (d, JC–P = 24.0 Hz), 87.24 (s), 9.91 (s) ppm. 31P{ H}
NMR (CDCl3): 63.2 (m), 18.0 (d, 2JP–P = 42 Hz) ppm. 19F NMR
(CDCl3): -100.8 (s) ppm. MS: 649 (M+, 100%). Anal. Calc. for
C34H35P3F7BFe: C, 55.46; H, 4.80%. Found: C, 55.5; H, 4.7%.
1
1
Conclusions
Nine-membered triphospha- and triarsamacrocycles with un-
saturated benzo-backbones have been prepared by a template
method based on [CpRFe]+ systems. The cyclisation involves the
attack of a coordinated phosphide (or arsenide) nucleophile at
an electrophilic ortho-fluorophenyl carbon suitably activated by
virtue of its disposition with regard to a coordinated phosphine.
The macrocycle assembly is of the ‘2 + 1’ type where two new
chelate rings are formed from appropriately derivatised bidentate
and monodentate phosphines/arsines. Both unsubstituted cy-
clopentadienyl and 1,2,3,4,5-pentamethylcyclopentadienyliron(II)
[(g5-C5H5)Fe(tribenzo-9aneP3-H2,PhF)]PF6, 7a. Triethylamine
(0.5 ml, 5 mmol) was added to a solution of 6a (0.57 g, 0.78
mmol) in THF (30 ml) and the reaction mixture heated to 60
◦C for 8 h. After cooling, the solvent was removed in vacuo to
1
give a yellow powder. Yield = 0.20 g (74%). H NMR (CDCl3,
400 MHz) d 7.8–8.2 (16H, m, ArH), 4.35 (5H, s, C5H5), 3.44 (d,
1
1JH–P = 379 Hz) ppm. 13C{ H} NMR (CDCl3, 100 MHz) d 165.03
1
(d, 1JC–F = 286.0 Hz), 131–135 (m) ppm. 31P{ H} NMR (CDCl3):
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The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 9525–9532 | 9531
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Table 1 Details of X-ray crystallographic data collection for the
2 (a) P. G. Edwards, R. Haigh, D. M. Li and P. D. Newman, J. Am. Chem.
Soc., 2006, 128, 3818; (b) A. R. Battle, P. G. Edwards, R. Haigh, D. E.
Hibbs, D. M. Li, S. M. Liddiard and P. D. Newman, Organometallics,
2007, 26, 377; (c) R. J. Baker and P. G. Edwards, J. Chem. Soc., Dalton
Trans., 2002, 2960; (d) P. G. Edwards, P. D. Newman and K. M. A.
Malik, Angew. Chem., Int. Ed., 2000, 39, 2922; (e) P. G. Edwards, P. D.
Newman and D. E. Hibbs, Angew. Chem., Int. Ed., 2000, 39, 2722; (f) P.
G. Edwards, J. S. Fleming and S. S. Liyanage, Inorg. Chem., 1996, 35,
4563.
3 (a) P. G. Edwards and M. L. Whatton, Dalton Trans., 2006,
442; (b) T. Albers and P. G. Edwards, Chem. Commun., 2007,
858.
4 M. J. Atherton, J. Fawcett, J. H. Holloway, E. G. Hope, A. Karac¸ar,
D. R. Russell and G. C. Saunders, J. Chem. Soc., Dalton Trans., 1996,
3215.
5 M. J. Atherton, J. Fawcett, J. H. Holloway, E. G. Hope, D. R. Russell
and G. C. Saunders, J. Organomet. Chem., 1999, 163, 582.
6 (a) O. Kaufhold, A. Stasch, T. Pape, A. Hepp, P. G. Edwards, P. D.
Newman and F. E. Hahn, J. Am. Chem. Soc., 2009, 131, 306; (b) A.
Flores-Figeroa, T. Pape, J. J. Weigand and F. E. Hahn, Eur. J. Inorg.
Chem., 2010, 2907.
complexes
3a
5
Empirical formula
Formula weight
Crystal system
Space group
C73H62BF2FeN4P3
1192.84
Monoclinic
P21/c
15.6204(3)
14.7050(3)
27.0880(6)
C73H62As3BF2FeN4
1324.69
Monoclinic
P21/c
15.6500(3)
14.7771(4)
27.3245(5)
˚
a/A
˚
b/A
˚
c/A
a (◦)
b (◦)
g (◦)
102.6900(10)
102.417(2)
3
˚
U/A
6070.1(2)
4
1.305
37 113
11 801
0.1505
0.0784, 0.1615
0.1707, 0.1946
6171.3(2)
4
1.426
21 135
13 900
0.0460
0.0834, 0.2585
0.1251, 0.3029
Z
Dc/Mg m-3
Reflections collected
Independent reflections
Rint
Final R1, wR2 [I > 2s(I)]
(all data)
7 E. P. Kyba and S-S. P. Chou;, J. Chem. Soc., Chem. Commun., 1980,
449.
8 G. Salem, G. B. Shaw, A. C. Willis and S. B. Wild, J. Organomet. Chem.,
1993, 455, 185.
templates can be employed for the cyclisation although the
former is preferred. The 9aneAs3 is the first example of a nine-
membered triarsamacrocycle. Crystal structures of the 9aneP3
and 9aneAs3 complexes show the unique conformation of these
original macrocycles with a ‘cup shaped’ cavity formed by the
rigid benzo-backbones.
9 A. Bader, Y. B. Kang, M. Pabel, D. D. Pathak, A. C. Willis and S. B.
Wild, Organometallics, 1995, 14, 1434.
10 W. Levason, M. L. Matthews, B. Patel, G. Reid and M. Webster,
Polyhedron, 2004, 23, 605.
11 Determined from
a survey of the Cambridge Crystallographic
Database, April 2011.
12 Medac LTD, Brunel Science Cntr, Coopers Hill Lane, Englefield Green,
Egham, Surrey, TW20 0JZ.
13 E. P. Kyba, M. C. Kerby and S. P. Rines, Organometallics, 1986, 5,
1189.
Acknowledgements
14 COLLECT, Nonius BV, 1998, Delft, The Netherlands.
15 Z. Otwinowski and W. Minor, Methods Enzymol., 1997, 276,
307.
We thank the EPSRC for studentships (TA, JB).
16 A. Altomare, G. Cascarano, C. Giacovazzo and A. Guagliardi, J. Appl.
Crystallogr., 1993, 26, 343.
Notes and references
17 G. M. Sheldrick, Institu¨t fu¨r Anorganische Chemie der Universita¨t,
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