Synthesis and structures of gold perfluorophthalimido complexes

Article abstract of DOI:10.1039/c0dt01134g

Compounds of the new tetrafluorophthalimido anion, [C₆F ₄(CO)₂N]^-, are readily accessible by treatment of tetrafluorophthalimide with either LiNPrⁱ₂ or mixtures of NEt₃ and Me₃ECl (E = Si or Sn), to give C ₆F₄(CO)₂N-X (X = Li 3, SiMe₃4, and SnMe₃5). The reaction of the trimethylsilyl derivative 4 with AgF leads cleanly to the ion pair complex [Ag(NCMe)₂][Ag(N(CO) ₂C₆F₄)₂] (6·2MeCN), which contains a linear [Ag{N(CO)₂C₆F₄} ₂]^- anion and a tetracoordinate Ag⁺ cation. Compound 6 reacts with iodine to give the N-iodo compound C₆F ₄(CO)₂NI 7, which crystallises as an acetonitrile adduct. Treatment of 6 with LAuCl affords LAu{N(CO)₂C₆F ₄} (L = Ph₃P 8a, Cy₃P 8b, or THT 9), whereas the reaction with AuCl in acetonitrile affords the heterobinuclear compound [Ag(MeCN)₂][Au{N(CO)₂C₆F₄} ₂]·MeCN (10·3MeCN). The tetrafluorophthalimido ligand is not readily displaced by donor ligands; however, the addition of B(C ₆F₅)₃(Et₂O) to a diethyl ether solution of 8a leads to the salt [Au(PPh₃)₂][N{COB(C ₆F₅)₃}₂C₆F₄)] 11. The analogous reaction of (THT)Au{N(CO)₂C₆F ₄} with B(C₆F₅)₃ in toluene in the presence of excess norbornene (nb) gives [Au(nb)₃][N{COB(C ₆F₅)₃}₂C₆F₄)] 12. Compounds 11 and 12 contain a new non-coordinating phthalimido-bridged diborate anion with O-bonded boron atoms. The crystal structures of compounds 2-11 are reported.

Full text of DOI:10.1039/c0dt01134g

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PAPER
Synthesis and structures of gold perfluorophthalimido complexes†
Nicky Savjani, Simon J. Lancaster, Sean Bew, David L. Hughes and Manfred Bochmann*
Received 31st August 2010, Accepted 15th November 2010
DOI: 10.1039/c0dt01134g
Compounds of the new tetrafluorophthalimido anion, [C6F4(CO)2N]-, are readily accessible by
treatment of tetrafluorophthalimide with either LiNPri2 or mixtures of NEt3 and Me3ECl (E = Si or
Sn), to give C6F4(CO)2N-X (X = Li 3, SiMe3 4, and SnMe3 5). The reaction of the trimethylsilyl
derivative 4 with AgF leads cleanly to the ion pair complex [Ag(NCMe)2][Ag(N(CO)2C6F4)2]
(6·2MeCN), which contains a linear [Ag{N(CO)2C6F4}2]- anion and a tetracoordinate Ag+ cation.
Compound 6 reacts with iodine to give the N-iodo compound C6F4(CO)2NI 7, which crystallises as an
acetonitrile adduct. Treatment of 6 with LAuCl affords LAu{N(CO)2C6F4} (L = Ph3P 8a, Cy3P 8b, or
THT 9), whereas the reaction with AuCl in acetonitrile affords the heterobinuclear compound
[Ag(MeCN)2][Au{N(CO)2C6F4}2]·MeCN (10·3MeCN). The tetrafluorophthalimido ligand is not
readily displaced by donor ligands; however, the addition of B(C6F5)3(Et2O) to a diethyl ether solution
of 8a leads to the salt [Au(PPh3)2][N{COB(C6F5)3}2C6F4)] 11. The analogous reaction of
(THT)Au{N(CO)2C6F4} with B(C6F5)3 in toluene in the presence of excess norbornene (nb) gives
[Au(nb)3][N{COB(C6F5)3}2C6F4)] 12. Compounds 11 and 12 contain a new non-coordinating
phthalimido-bridged diborate anion with O-bonded boron atoms. The crystal structures of compounds
2–11 are reported.
Introduction
Results and discussion
Gold complexes with electron withdrawing p-ligands, particularly
perfluorophenyl complexes, show a remarkable and versatile
chemistry.1 As part of our interest in the coordination chemistry of
heavy metals with labile ligands,2 we decided to explore complexes
of the tetrafluorophthalimido anion, [C6F4(CO)2N]- since this
ligand suggested the possibility of extensive charge delocalisation,
coupled with the presence of fluorine and C O moieties as
reporter functions for changes in the electronic and bonding
characteristics. Gold imidinato complexes have a long history,3
not least because of potential medical applications,4 whereas
metal complexes of the tetrafluorophthalimido ligand have, to our
knowledge, not been described before.
Tetrafluorophthalimide was first synthesised by Gething et al.
who reacted tetrafluorophthalic acid with an aqueous solution of
ammonia, followed by condensation and sublimation, although
the yield was low.5 A significantly improvement is achieved
using a two-step procedure via the anhydride 1, followed by
ammonolysis with urea.6,7 The product was extracted into hot
anisole to give the tetrafluorophthalimide 2 in 71% overall yield
(Scheme 1).
Crystals of 2 were grown from slow cooling of an anisole
solution and the compound was characterised by X-ray diffraction
(Fig. 1). The molecules are planar (C5-C6-N7-H7 torsion angle
179.8◦), with extensive conjugation between the nitrogen atom and
the C O moieties. This is reflected in the low Lewis basicity of 2,
i.e. its failure to react with a number of strong Lewis acids (AlX3,
BX3, where X = F, Cl, Br, C6F5). In the crystal the molecules form a
hydrogen-bonded network in a corkscrew-like arrangement, where
the N–H unit of one molecule interacts with one of the two oxygen
Wolfson Materials and Catalysis Centre, School of Chemistry, University
of East Anglia, Norwich, NR4 7TJ, UK. E-mail: m.bochmann@uea.ac.uk;
Fax: +44 01603 592044
† CCDC reference numbers 791405–791409, 791410–791414. For crys-
tallographic data in CIF or other electronic format see DOI:
10.1039/c0dt01134g
˚
atoms of a neighbouring molecule (N–H ◊ ◊ ◊ O 2.07(3) A).
Scheme 1 Synthesis of tetrafluorophthalimide.
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Fig. 1 Crystal packing of 2, with partial labelling scheme; unit cell depicted with the hydrogen bonding shown to illustrate the corkscrew orientation.
◦
˚
Selected bond lengths (A) and angles ( ): C(6)–N(7) 1.389(3), N(7)–C(8) 1.380(3), C(6)–O(6) 1.205(3), C(8)–O(8) 1.212(3), N(7)–H(7) 0.80(3), H(7) ◊ ◊ ◊ O(8¢)
2.07(3); N(7)–H(7)–O(8¢) 171(3).
The acidic N–H function of 2 can readily be metallated.
Initial attempts to synthesise the lithium phthalimide 3 were
unsuccessful; for example, the reaction of n-butyl lithium in
THF solution at -78 ◦C gave a deep red product, the 19F
NMR spectrum of which revealed a large number of broadened
peaks. On the other hand, replacing n-butyl lithium with lithium
bis(trimethylsilyl)amide under the same conditions generated the
trimethylsilyl phthalimide 4 in moderate yield (~40%) (Scheme 2).
The lithium phthalimide is however accessible in good yield
from 2 and lithium diisopropylamide in diethyl ether as a
red, amorphous solid. Attempts to obtain crystals failed. The
compound contained variable amounts of diethyl ether and a
satisfactory elemental analysis could therefore not be obtained;
however, the 19F NMR and infrared spectroscopic data confirmed
the presence of the phthalimido anion. In particular, the n(C O)
stretching frequency is reduced from 1740 cm-1 in 2 to 1640 cm-1
in 3.
The trimethylsilyl derivative 4 is more conveniently prepared by
treating 2 with triethylamine and excess trimethylsilyl chloride. An
analogous procedure using Me3SnCl affords the trimethylstannyl
derivative 5.
Crystals of 4 could be grown by cooling a light petroleum
solution, while those of 5 were grown from diethyl ether. The
molecular structures of 4 and 5 are shown in Fig. 2 and 3,
respectively. Both unit cells contain two independent but near-
identical molecules but with very different packing arrangements:
whereas the silyl compound shows approximately parallel but
alternating stacking of the tetrafluorophthalimido groups, the tin
analogue does not.
The N-silyl derivative 4 is a useful phthalimide anion equiv-
alent. Thus the reaction of 4 with AgF in acetonitrile at room
temperature gives the argentate salt Ag[Ag{N(CO)2C6F4}2] 6
in almost quantitative yield. While the solvent of crystalli-
sation is readily lost under vacuum, recrystallisation of this
complex from acetonitrile layered with diethyl ether gives the
adduct [(MeCN)2Ag][Ag{N(CO)2C6F4}2] as pale-brown crystals
Scheme 2 Preparation of metallated perfluorophthalimido compounds.
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Fig. 2 Molecular structures of two independent molecules of 4 (left) and its packing in the crystal (right), illustrating differences in packing within
˚
the unit cell. Selected bond lengths (A):4: Molecule 1: C(2)–N(1) 1.405(7), N(1)–C(9) 1.402(7), C(2)–O(2) 1.207(6), C(9)–O(9) 1.212(6), N(1)–Si(1)
1.821(5). Molecule 2: C(12)–N(11) 1.391(8), N(11)–C(19) 1.400(8), C(12)–O(12) 1.220(8), C(19)–O(19) 1.190(7), N(11)–Si(2) 1.831(5).
˚
Fig. 3 Molecular structures of two independent molecules of 5, showing the atomic numbering scheme. Selected bond lengths (A): Molecule 1: C(2)–N(1)
1.390(3), N(1)–C(9) 1.383(3), C(2)–O(2) 1.208(3), C(9)–O(9) 1.217(3), N(1)–Sn(1) 2.183(2). Molecule 2: C(12)–N(11) 1.401(3), N(11)–C(19) 1.378(3),
C(12)–O(12) 1.208(3), C(19)–O(19) 1.215(3), N(11)–Sn(11) 2.156(2).
˚
(Scheme 3). The same product can be obtained using the tin
reagent 5 (91% yield); however, removal of the Me3SnF by-product
is less convenient.
The distance between the two silver atoms is 3.0172(3) A, well
above the sum of the covalent radius for Ag(I) in the anion in 6
+
˚
˚
(1.33 A) and the ionic radius of tetracoordinate Ag (1.15 A). The
The crystal structure of 6·2MeCN (Fig. 4) reveals that the
compound contains two different silver environments: a linear
bis(phthalimido)argentate(I) anion which coordinates in chelate
fashion to an [Ag(MeCN)2]+ cation via two of the carbonyl
moieties.8 The geometry of the latter is a strongly flattened
tetrahedron, with wide O–Ag–O and N–Ag–N angles in the range
of 137–142◦ and consequently more acute N–Ag–O angles. The
two planes of the phthalimido ligands are parallel to one another.
structure is reminiscent of the succinimidate [Ag(H2O)][Ag(suc)2],
˚
which shows similar Ag–N distances of 2.079(5) and 2.067(5) A but
also coordination of the Ag+ ion to an O-atom of a neighbouring
succinimidate.9
Whereas the reactions of the Si and Sn compounds 4 and 5
with Cl2 and Br2 under mild conditions gave only the parent
phthalimide 2 as the only isolable product, while there was no
reaction with iodine, the reaction of the silver salt 6 with iodine
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Scheme 3 Preparation and reactions of silver and gold perfluorophthalimido complexes.
˚
Fig. 4 Molecular structure of [(MeCN)2Ag][Ag{N(CO)2C6F4}2] (6·2MeCN) showing the atom numbering scheme. Selected bond lengths (A) and
angles (◦): Ag(1)–N(1) 2.065(2), Ag(1)–N(11) 2.074(2), Ag(2)–O(9) 2.4616(17), Ag(2)–O(12) 2.4885(17), Ag(2)–N(31) 2.219(2), Ag(2)–N(41) 2.238(2),
N(1)–C(9) 1.362(3), N(1)–C(2) 1.381(3); N(1)–Ag(1)–N(11) 174.16(8), O(9)–Ag(2)–O(12) 137.18(6), N(31)–Ag(2)–N(41) 142.45(9), O(9)–Ag(2)–N(41)
83.31(8), O(9)–Ag(2)–N(31) 112.53(7), O(12)–Ag(2)–N(41) 95.91(8), O(12)–Ag(2)–N(31) 93.95(7).
˚
in dry dioxane under the exclusion of light produced the N-iodo
compound C6F4(CO)2NI 7 as a yellow powder in good yield (82%)
(Scheme 3). The n(CO) frequency was observed at 1702 cm-1,
slightly lower than in 2 (1740 cm-1). Recrystallisation of 7 from
acetonitrile at -28 ◦C gave crystals of the adduct 7·MeCN (Fig. 5).
The whole of the phthalimide molecule lies on a mirror-plane of
symmetry. Only the nitrogen atom of the MeCN solvent refined
slightly away from the same plane. While the formation of an
acetonitrile adduct indicates a positively polarised iodine atom,
the iodine-nitrogen distance of 2.601(19) A is substantially longer
than the iodine-nitrogen distances in cationic iodine complexes
+
10
˚
(cf. [I(NCMe)2] , 2.198(3) A).
˚
The molecular planes of 7 are separated by 3.152 A (half
the b cell length), but the phthalimide molecules overlap only
peripherally with closest contact C(7) ◊ ◊ ◊ C(7¢) at 3.173(2) A.
The phthalimide and the MeCN molecules are aligned with
N(1)–I(1) ◊ ◊ ◊ N(11)–C(12) almost linear, with a short I(1) ◊ ◊ ◊ N(11)
interaction.
˚
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◦
˚
Fig. 5 Molecular structure of C6F4(CO)2NI·MeCN 7·MeCN, showing the atom numbering scheme. Selected bond lengths (A) and angles ( ):
N(1)–C(2) 1.405(17), N(1)–C(9) 1.391(14), C(2)–O(2) 1.184(14), C(9)–O(9) 1.214(15), I(1)–N(1) 2.074(9), N(11)–C(12) 1.15(3), I(1) ◊ ◊ ◊ N(11) 2.601(19);
C(2)–N(1)–I(1) 121.2(7), C(9)–N(1)–I(1) 125.5(8), C(9)–N(1)–C(2) 113.4(9), O(2)–C(2)–N(1) 124.7(11), N(1)–I(1) ◊ ◊ ◊ N(11) 174.6(3), C(12)–N(11)–I(1)
168.5(10).
Fig. 6 The two independent molecules of 8a showing a partial atomic numbering scheme (left) and side view of the stacking arrangement (right) in which
◦
˚
molecules are stacked in groups of four almost parallel ring systems about a centre of symmetry. Selected bond lengths (A) and angles ( ): Au(1)–P(1)
2.2370(11), Au(1)–N(41) 2.058(4), Au(2)–P(6) 2.2336(12), Au(2)–N(91) 2.042(4); N(41)–Au(1)–P(1) 171.19(11), N(91)–Au(2)–P(6) 173.90(11).
Although, in view of the electron withdrawing character of the
C6F4(CO)2N moiety, compound 7 could be expected to readily
undergo oxidative addition reactions, e.g. with gold(I) phosphine
complexes, no such reactions were observed, and the starting
materials were recovered.
The reaction of AuCl(PPh3) with either the silver salt 6 or
lithium phthalimide 3 in acetonitrile at room temperature gives
(triphenylphosphine)gold tetrafluorophthalimide 8a as colourless
crystals in good yields (77 and 74% respectively). This complex
is stable to air and moisture. The carbonyl stretch is observed
at 1678 cm-1, indicative of the accumulation of partial negative
charge on the N-ligand. The tricyclohexylphosphine analogue 8b
was prepared similarly. A number of related succinimidato and
heterocyclic gold(I) phosphine complexes are known.11,12 Crystals
of both products were grown from toluene.
The essentially coplanar phthalimido ligands are arranged at an
angle of about 90◦ (Fig. 6), such that a C O moiety of one ligand
is positioned on top of the six-ring of the second. Complex 8b crys-
tallises with a (disordered) molecule of toluene (Fig. 7). Molecules
are stacked in columns: pairs of phthalimide ligands are parallel
about a centre of symmetry, with close contacts between over-
lapping edges, e.g. C(14) ◊ ◊ ◊ F(14¢) 3.185, N(11) ◊ ◊ ◊ C(14¢) 3.226,
C(12) ◊ ◊ ◊ C(14¢) 3.264, C(12) ◊ ◊ ◊ C(13¢) 3.270 and C(13) ◊ ◊ ◊ C(13¢)
˚
3.272 A. On the opposite faces, there are the disordered toluene
molecules, tilted at 17.3(4)◦ to the phthalimide planes, with
close contacts of F(14) ◊ ◊ ◊ C(53) 3.183, C(14) ◊ ◊ ◊ C(52) 3.304 and
˚
C(13) ◊ ◊ ◊ C(52) 3.567 A.
The bond lengths show remarkably little variation with the
nature of the phosphine ligands, with 8b showing a slightly longer
Au–P and slightly shorter Au–N distance than 8a. However, both
compare well with related non-fluorinated complexes, notably
The molecular structures of 8a and 8b are shown in Fig. 6 and
7, respectively. Both have the expected linear gold coordination
geometry. The unit cell of 8a contains two independent molecules.
13
˚
(Et3P)Au{N(CO)2C6H4} (Au–P 2.238(6), Au–N 2.05(2) A) and
14
˚
with (Ph3P)Au{N(CO)2C6H4} (Au–N 2.028(4) and 2.040(4) A).
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shorter than in the phosphine analogues; evidently the weaker
donor strength of the sulfur ligand is replaced by tighter anion
binding and aurophilic interactions.
Attempts to generate perfluorophthalimido complexes of the
LAuX type with even weaker ligands L, such as acetonitrile, were
only partially successful. Although the reaction of 6 with AuCl
in a 1 : 1 stoichiometric ratio in acetonitrile gave a pale yellow
solution which contained a single phthalimido complex (by 19F
NMR spectroscopy), the attempted isolation and crystallisation
led to decomposition and formation of a gold film. On the
other hand, the reaction of AuCl with two equivalents of 6
yielded the mixed-metal complex Ag[Au{N(CO)2C6F4}2] 10 as
a brown powder. Crystals of this compound were grown by
the slow cooling of a hot acetonitrile solution. This affords the
adduct [(MeCN)2Ag][Au{N(CO)2C6F4}2]·MeCN (10·3MeCN).
The structure (Fig. 9) resembles that of 6·2MeCN, except that
the phthalimido ligands have been transferred to gold.
The bis(phthalimido)aurate anion is linear. The Au–N distances
˚
in 10 are ca. 0.03–0.05 A shorter than in the neutral complexes
8 and 9. We are aware of only one crystallographically char-
acterised precedent for a structure of this type, sodium bis(1-
methylhydantoinato)gold·4H2O, for which a slightly shorter Au–N
4b
˚
bond length of 1.94 A has been reported.
Unlike in 6, the phthalimido ligands in 10 are twisted with
respect to one another, with a dihedral angle of 14.8◦. The
aurate anion binds to a silver cation via two of the carbonyl
oxygen atoms, but with two distinctly different Ag ◊ ◊ ◊ O distances,
unlike the near-symmetrical chelate found in 6·2MeCN. The
Ag ◊ ◊ ◊ O coordination is reflected in the infrared spectrum which
shows two C O stretching bands at 1653 and 1620 cm-1
for the non-coordinated and the silver-bound C O moieties,
respectively. The non-bonding distance of the two metal centres is
˚
2.9544(2) A.
Fig. 7 Molecular structure of (Cy3P)Au{N(CO)2C6F4}·toluene 8b, show-
While there was no evidence of lability of gold-bound phthal-
imide or its displacement by excess phosphine, the ligand is easily
removed from the coordination sphere on addition of B(C6F5)3.
Thus, treating 8a with B(C6F5)3(Et2O) in diethyl ether at room tem-
perature for 15 min generates [Au(PPh3)2][N{COB(C6F5)3}2C6F4]
11, which contains a perfluorophthalimido-bridged diborate an-
ion. The borane molecules are bonded to the O atoms; there
is no evidence for formation of an N-bonded borate. The B–O
bonding is reflected in the n(CO) frequencies which change from
1678 cm-1 for 8a to 1545 cm-1 in 11. Crystals of 11 were grown
from a minimum amount of toluene layered with light petroleum
at -30 ◦C and obtained as pale yellow platelets. The structure of
11 (Fig. 10) shows a linear [Au(PPh3)2]+ cation supported by the
bulky phthalimidodiborate anion; there are no close cation-anion
interactions.
˚
ing the atomic numbering scheme. Selected bond lengths (A) and angles
(◦): Au–P(2) 2.2476(9), Au–N(11) 2.052(3); N(11)–Au–P(2) 172.54(9).
These Au–N bond lengths are longer than typical gold amide
15
˚
bonds, e.g. in (Ph3P)AuN(SiMe3)2 (2.027 A), ; they are however
˚
about 0.05 A shorter than the Au–N distance in (Ph3P)Au(NTf2)
16
˚
(Au–P 2.231, Au–N 2.102 A), a good indication that anionic
charge delocalisation in phthalimides and perfluorophthalimides
is much less effective than in the N(SO2CF3)2 anion. In line
with this observation, the complexes 8a and 8b do not re-
act with diphenylacetylene, bis(trimethylsilyl)acetylene, cyclooc-
tyne, norbornene, methyl acrylate, CO, trimethylsilylcyanide, t-
butylcyanide or excess tricyclohexylphosphine.
In an attempt to generate phthalimido complexes with
more labile donor ligands, the tetrahydrothiophene complex
(THT)Au{N(CO)2C6F4} 9 was prepared by a similar route. The
compound is stable to air and moisture but light sensitive, giving
the colourless crystals a purple hue after exposure for a day. The
molecular structure is shown in Fig. 8. The compound crystallises
with one molecule of toluene. While the N–Au–S moiety has the
expected linear geometry, the packing arrangement in the crystal is
rather different from that in 8a and 8b and shows minimal overlap
between the phthalimide ligands of two neighbouring molecules.
Instead, the Au atoms are arranged to form a chain based on
Au ◊ ◊ ◊ Au interactions. The Au–N distance in 9·toluene is notably
Since the starting material has a P : Au ratio of 1 : 1, attempts
were made to use this reaction for the preparation of mixed-ligand
gold complexes of the type [(R3P)AuL¢]+ in the presence of L¢ =
norbornene or 1,5-cyclooctadiene (PR3 = PPh3 or PCy3). There
was no evidence for the formation of such compounds. However,
the reaction of the more labile tetrahydrothiophene complex 9 with
B(C6F5)3 in toluene in the presence of excess norbornene at 0 ◦C
resulted in the displacement of the sulfur ligand and formation of
[Au(nb)3][{N(COB(C6F5)3}2C6F4] 12. Crystals were grown from
◦
dichloromethane at -30 C. The [Au(nb)3]+ cation has recently
-
been reported as the SbF6 salt;17,18
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◦
˚
Fig. 8 Molecular structure (top) and packing arrangement of 9·toluene. Selected bond lengths (A) and angles ( ): Au–S(1) 2.264(4), Au–N(11) 2.025(12),
Au–Au¢ 3.3218(3); N(11)–Au–S(1) 179.5(3); Au¢-Au–Au¢¢ 172.58(4).
Table 1 Comparison of IR and 19F NMR data (in CDCl3)
Comparison of spectroscopic characteristics of the
tetrafluorophthalimido ligand
19F NMR
The tetrafluorophthalimido ligand allows the fluorine atoms
and C O functions to be used as probes for the electronic
characteristics. A comparison of these data is given in Table 1.
The C O stretching frequencies show the expected reduction with
increasing anionic character of the ligand but are little influenced
by the donor strength of ligands coordinated to gold, e.g. the values
for the PPh3, PCy3 and THT complexes are identical. The ionic
O-chelate 10 shows two C–O bands, the higher of which is reduced
by 87 cm-1 compared to the parent phthalimide 2, while the second
shows a further reduction by 33 cm-1 due as a result of coordination
to Ag+. There is however a more substantial reduction in C–
O bond order on borane coordination; e.g. the corresponding
absorption for compound 11 is almost over 190 cm-1 lower than
n(CO) in 2.
Compound
IR nC O/cm-1
Solvent
Signal 1 Signal 2
Dd
2
1740
1740
1640
1706
1706
1587
1702
1678
1679
1678
1653, 1620
1545
n.d.
CDCl3
CD3CN
THF-d8
CDCl3
CDCl3
CD3CN
CD3CN
CDCl3
CDCl3
CDCl3
CD3CN
CDCl3
CDCl3
-134.7
-139.9
-143.7
-137.0
-137.9
-143.6
-139.4
-139.2
-139.7
-138.8
-143.0
-133.5
-132.1
-141.2
-146.0
-152.5
-142.7
-144.2
-150.7
-146.5
-145.9
-146.4
-145.9
-149.7
-141.0
-141.3
6.5
6.5
8.8
5.7
6.3
7.1
7.1
6.7
6.7
7.1
6.7
7.5
9.2
2
3
4
5
6
7
8a
8b
9
10
11
12
by the solvent than by any negative charge or donor ligands in
the complex. In spite of the presence of F substituents, there is
evidently very limited charge delocalisation over the C6F4 part of
the phthalimido ligand.
By comparison, given the wide 19F chemical shift range, the
variations of the 19F signals for this set of complexes are quite
small; in fact the chemical shift are more strongly influenced
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Fig. 9 Molecular structure of [(MeCN)2Ag][Au{N(CO)2C6F4)}2]·MeCN (10·3MeCN), showing the atomic numbering scheme. Selected bond lengths
◦
˚
(A) and angles ( ):Au–N(1) 1.9972(17), Au–N(11) 2.0030(17), Ag–O(2) 2.4358(16), Ag–O(19) 2.6598(15), Ag–N(21) 2.207(2), Ag–N(31) 2.194(2).
N(1)–Au–N(11) 177.73(7), N(21)–Ag–N(31) 130.95(8), O(2)–Ag–O(19) 140.68(5).
˚
Fig. 10 Crystal structure of [Au(PPh3)2][{N(COB(C6F5)3}2C6F4] 11, showing a partial atomic numbering scheme. Selected bond lengths (A) and
angles (◦): Au–P(1) 2.297(5), Au–P(2) 2.301(5), B(3)–O(32) 1.57(2), B(9)–O(39) 1.55(3), N(31)–C(32) 1.31(2), N(31)–C(39) 1.31(2), C(32)–O(32) 1.23(2),
C(32)–C(33) 1.48(2), C(33)–C(38) 1.37(2); P(1)–Au–P(2) 169.53(19), B(3)–O(32)–C(32) 128.0(14), O(32)–C(32)–N(31) 131.8(17), N(31)–C(39)–O(39)
131.0(17), C(39)–O(39)–B(9) 127.1(14), C(32)–N(31)–C(39) 113.3(15).
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for 10 min, upon which the contents melted and then re-solidified.
The crude phthalimide was dissolved in the minimum amount of
hot anisole (40 mL), filtered and recrystallised at 2 ◦C to produce
yellow crystals of 2 (4.42 g, 20.2 mmol, 78%). 19F NMR (CDCl3,
282.4 MHz): d -134.7 (2F, dd, JF–F = 19.8, 8.5 Hz, F2, F5), -141.2
(2F, dd, JF–F = 19.8, 8.5 Hz, F3, F4). 19F NMR (CD3CN, 282.4
MHz): d -139.9 (2F, dd, JF–F = 19.8, 8.5 Hz, F2, F5), -146.0 (2F,
dd, JF–F = 19.8, 8.5 Hz, F3, F4). IR: 1740 cm-1 n(C O).
Conclusions
Tetrafluorophthalimido ligands readily form complexes with Li,
Si, Sn, I, Ag and Au. The Si and Sn derivatives are useful
phthalimide anion equivalents. While gold complexes of the type
LAu(phthalimide) have ample structural precedents, in the absence
of donor ligands the less common linear [M(phthalimide)2]- are
formed (M = Ag or Au) which form heterobimetallic structures
with Ag+ ions. The Au–N bonds in phosphine gold complexes
LAu{N(CO)2C6F4} are only very slightly longer than those in
non-fluorinated analogues, which points to a surprisingly small
influence of the C6F4 ring on the bonding character of this ligand.
In line with this, there was no displacement of the [N(CO)2C6F4]-
ion by excess phosphines. On the other hand, the addition of the
strongly Lewis acidic borane B(C6F5)3 led to facile phthalimide
abstraction and the formation of a new non-coordinating diborate
anion. This method can be used for the generation of gold
complexes with weak donor ligands such as olefins.
Lithium tetrafluorophthalimide (3)
To a solution of 2 (1.05 g, 4.8 mmol) in diethyl ether (20 mL)
was added a solution of LiNPri2 (0.512 g, 4.8 mmol) in diethyl in
-78 ◦C. The mixture was stirred for 1 h to give an orange solution
which was allowed to warm to room temperature. Removal of the
solvent left 3 as an orange solid. The attempted recrystallisation
by dissolving this solid in diethyl ether (20 mL) and layering with
toluene at 2 ◦C resulted in the precipitation of a powder (740 mg,
3.3 mmol, 69%). 19F NMR (THF-d8, 282.4 MHz): d -143.7 (2F,
br. s, F2, F5), -152.5 (2F, br. s, F3, F4). IR (nujol mull) 1640 cm-1
n(C O).
Experimental
All manipulations were performed under dry nitrogen, using
standard Schlenk techniques. Nitrogen was purified by passing
through columns of supported P2O5, with moisture indicator,
N-Trimethylsilyltetrafluorophthalimide (4)
In a 1 L round bottom flask, 2 (13.6 g, 62 mmol) was dissolved
in 300 mL dry THF and cooled to -80 ◦C. To this was added
trimethylchlorosilane (15.7 mL, 124 mmol) followed by dry
triethylamine (8.7 mL, 62 mmol). A white precipitate formed.
The reaction was warmed to 20 ◦C and stirred for 1h. The solvent
was removed in vacuo, the residue dissolved in light petroleum
and recrystallised at 2 ◦C to yield yellow needles. The crystals
were filtered off and washed with cold petroleum to produce 4
˚
and activated 4 A molecular sieves. Solvents were pre-dried over
sodium wire (toluene, light petroleum, THF, diethyl ether) or
calcium hydride (dichloromethane), and distilled under argon over
sodium (toluene), sodium-potassium alloy (light petroleum, bp
40–60 ◦C), sodium-benzophenone (THF, diethyl ether) or calcium
hydride (dichloromethane). LiNPri2,19 LiN(SiMe3)2,20 (Ph3P)AuCl
and (Cy3P)AuCl21 were prepared following literature methods.
˚
Deuterated solvents were stored over activated 4 A molecular
1
as pale yellow needles (8.1 g, 28 mmol, 45%). H NMR (CDCl3,
sieves and degassed by several freeze-thaw cycles.
300 MHz): d 0.48 (9H, s, Me). 19F NMR (CDCl3, 282.4 MHz):
d -137.0 (2F, dd, JF–F = 19.8, 8.5 Hz, F2, F5), -142.7 (2F, dd,
Infrared spectra were obtained using a Perkin Elmer Spec-
trum BX FT-IR spectrometer equipped with a diamond ATR
1
JF–F = 19.8, 8.5 Hz, F3, F4). 13C{ H} NMR (CDCl3, 75.5 MHz): d
1
attachment. 1H, 13C{ H}, 11B and 19F NMR spectra were recorded
-0.51 (s, Me), 115.81 (s, ipso-C), 142.4 (dm, JC–F = 271 Hz, Ar-C),
144.3 (dm, JC–F = 278 Hz, Ar-C), 166.5 (s, C O). IR (powder)
1706 cm-1 n(C O). Anal. found: C, 45.41 H, 3.00; N, 4.91%.
Calcd for C11H9F4NO2Si: C, 45.36; H, 3.11; N, 4.81.
1
using a Bruker DPX300 spectrometer. H NMR spectra (300.13
MHz) were referenced to the residual protons of the deuterated
solvent used. 13C NMR spectra (75.47 MHz) were referenced
internally to the D-coupled 13C resonances of the NMR solvent.
11B (96.3 MHz) and 19F (282.4 MHz) NMR spectra were referenced
externally to BF3·Et2O or CFCl3, respectively. Elemental analyses
were performed by London Metropolitan University.
N-Trimethylstannyltetrafluorophthalimide (5)
The compound was made following the procedure described for
4, with the exception that the product was recrystallised from
diethyl ether at 2 ◦C to. Yellow crystals of 5 were obtained (5.65 g,
Synthesis of tetrafluorophthalimide (2)
1
14.9 mmol, 67%). H NMR (CDCl3, 300.1 MHz): d 0.72 (9H, s,
The synthesis was adapted from literature procedures.6,7 A 250 mL
three-necked flask with a reflux condenser and an addition funnel
was charged with 2,3,4,5-tetrafluorophthalic acid (25.1 g, 105.4
mmol◦). Thionyl chloride (40 mL) was added dropwise over 15 min
Me). 19F NMR (CDCl3, 282.4 MHz) d -137.9 (2F, dd, JF–F
=
19.8, 8.5 Hz, F2, F5), -144.2 (2F, dd, JF–F = 19.8, 8.5 Hz, F3, F4).
1
13C{ H} NMR (CDCl3, 75.5 MHz): d -3.71 (s, Me), 116.4 (s, ipso-
C), 142.6 (dm, JC–F = 263 Hz, Ar-C), 144.6 (dm, JC–F = 274 Hz,
Ar-C), 169.0 (s, C O). IR (powder): 1706 cm-1 n(C O). Anal.
Found: C, 34.71; H, 2.45; N, 3.70. Calcd for C11H9F4NO2Sn: C,
34.60; H, 2.38; N, 3.67%.
◦
at 60 C. The subsequent white suspension was heated to 90 C
overnight to afford a light-brown solution. The excess thionyl
chloride was removed in vacuo and the resulting ivory solid dried
under vacuum. The crude tetrafluorophthalic anhydride 1 (22.1 g,
95.9 mmol, 91%) was used without further purification. The
analytical data for this compound were in agreement with the
literature data.6
Disilver bis(tetrafluorophthalimide) (6)
In a 250 mL round bottom flask, the silyl derivative 4 (4.40 g, 15.1
mol) was dissolved in 70 mL dry acetonitrile and silver fluoride
(1.92 g, 15.1 mmol) was added. The mixture was stirred at room
For the conversion into the phthalimide, a mixture of 1 (5.70 g,
25.9 mmol) and urea (1.63 g, 27.2 mmol) was heated at 135 ◦C
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temperature for 30 min to yield a hazy solution. The solvent was
removed in vacuo. The straw coloured solid residue was redissolved
in dry acetonitrile (20 mL). Addition of diethyl ether (50 mL)
yielded a fluffy straw-coloured solid which was filtered off, washed
with diethyl ether and dried to give 6 (4.51 g 6.9 mmol, 92%).
The compound can be obtained free of coordinating solvent by
prolonged evacuation. 19F NMR (CD3CN, 282.4 MHz): d -143.6
121.5 MHz): d 50.9 (s). IR (powder): 1679 cm-1 n(C O). Anal.
Found: C, 50.25; H, 5.18; N, 1.71. Calcd for C33H41AuF4NO2P: C,
50.32; H, 5.25; N, 1.78%.
Synthesis of (C4H8S)Au{N(CO)2C6F4} (9)
Using the procedure described for 8a, 9 was obtained from
(THT)AuCl as pale yellow crystals (283 mg, 0.56 mmol, 56%).
The crystals grown were suitable for single crystal X-ray analysis.
1H NMR (CDCl3, 300.1 MHz): d 2.21 (4H, br. s), 3.42 (4H, br.
s). 19F NMR (CDCl3, 282.4 MHz) d -138.8, (2F, dd, JF–F = 19.8,
1
(4F, m, F2, F2¢, F5, F5¢), -150.7 (4F, m, F3, F3¢, F4, F4¢). 13C{ H}
NMR (CD3CN, 75.5 MHz): d 119.1 (s, ipso-C), 141.3 (dm, JC–F
=
263 Hz, Ar-C), 143.3 (dm, JC–F = 261 Hz, Ar-C), 173.9 (s, C O).
IR (powder): 1587 cm-1 n(C O). Anal. Found: C, 29.33; N, 4.32.
Calcd for C16Ag2F8N2O4: C, 29.48; N, 4.30%. For single crystal
X-ray analysis, the product was recrystallised from acetonitrile
layered with diethyl ether, to give pale straw coloured needles of
6·2MeCN.
1
8.5 Hz, F2, F5), -145.9 (2F, dd, JF–F = 19.8, 8.5 Hz, F3, F4). 13C{ H}
NMR (CDCl3, 75.5 MHz): d 30.4 (s, THT), 39.8 (s, THT), 120.2 (s,
ipso-C), 141.7 (dm, JC–F = 266 Hz, Ar-C), 144.4 (dm, JC–F = 271 Hz,
Ar-C), 170.9 (s, C O). IR (powder): 1678 cm-1 n(C O). Anal.
Found: C, 28.74; H, 1.66; N, 2.85. Calcd for C26H15AuF4PO2N: C,
28.64; H, 1.60; N, 2.78%.
N-Iodo(tetrafluoro)phthalimide (7)
To a solution of iodine (0.76 g, 3.00 mmol) in dry 1,4-dioxane
(10 mL) was added 6 (1.00 g, 3.06 mmol). The reaction was stirred
in the dark for 10 min. After removal of the solvent under vacuum
at 40 ◦C, the residue was taken up in acetonitrile, the silver iodide
filtered off and the orange filtrate concentrated in vacuo to give
the N-iodo compound 7 as a yellow solid (0.84 g, 2.43 mmol,
Synthesis of Silver bis(tetrafluorophthalimido)aurate(I) (10)
To a solution of 6 (0.810 g, 1.24 mmol) in acetonitrile (20 mL)
was added AuCl (142 mg, 0.61 mmol). The mixture was stirred for
30 min. The resulting mixture was filtered through celite to give a
pale-brown solution. The solvent was removed and the residue was
dried. The reaction yielded 10 as a dark brown powder (282.4 mg,
0.38 mmol, 63%). 19F NMR (CD3CN, 282.4 MHz) d -143.0 (4F,
82%). 19F NMR (CD3CN, 282.4 MHz): d -139.4 (2F, dd, JF–F
=
19.8, 8.5 Hz, F2, F5), -146.5 (2F, dd, JF–F = 19.8, 8.5 Hz, F3,
F4). IR (nujol mull): 1702 cm-1 n(C O). Anal. Found: C, 27.89;
N, 4.17. Calcd for C8F4INO2: C, 27.85; N, 4.06%. Crystallisation
from acetonitrile gave crystals of 7·MeCN.
dd, JF–F = 17.0, 5.7 Hz, F2, F2¢, F5, F5¢), -149.7 (4F, dd, JF–F
=
1
17.0, 5.7 Hz F3, F3¢, F4, F4¢). 13C{ H} NMR (CD3CN, 75.5 MHz):
d 141.9 (dm, JC–F = 256 Hz, Ar-C), 143.8 (dm, JC–F = 266 Hz,
Ar-C), 171.7 (s, C O). Further analysis was carried out after
removing the solvent molecules in a vacuum; IR (powder): 1653
and 1620 cm-1 n(C O). Anal. Found: C, 26.01; N, 3.70. Calcd
for C16F8AgAuN2O4: C, 25.93; N, 3.78%. For single crystal X-
ray analysis, a hot concentrated acetonitrile solution was allowed
to cool slowly, resulting in the formation of brown crystals of
[(MeCN)2Ag][Au{N(CO)2C6F4}2]·MeCN (10·3MeCN).
Synthesis of (Ph3P)Au{N(CO)2C6F4} (8a)
To a solution of 6 (0.502 g, 1.55 mmol) in dry acetonitrile (50 mL)
was added (triphenylphosphine)gold(I) chloride (0.768 g, 1.55
mmol). The reaction was stirred at room temperature for 30 min.
The resulting mixture was filtered through celite to give a clear
yellow–green solution. The solvent was removed and the residue
recrystallized from the minimum amount of toluene, to yield 8a
as colourless crystals (0.790 g, 1.19 mmol, 77%). The crystals
were suitable for single crystal X-ray analysis. 1H NMR (CDCl3,
300.1 MHz): d 7.5 (m, Ph). 19F NMR (CDCl3, 282.4 MHz) d
Attempted synthesis of (tetrafluorophthalimido)gold(I)·acetonitrile
The procedure described for 10 was used, except that a 1 : 1
stoichiometric ratio of 6 and AuCl was used. A pale yellow
acetonitrile solution resulted. 19F NMR (CDCl3, 282.4 MHz) d
-139.2 (2F, dd, JF–F = 22.6, 5.6 Hz, F2, F5), -145.9 (2F, dd, JF–F
=
1
22.6, 5.6 Hz, F3, F4). 13C{ H} NMR (CDCl3, 75.5 MHz): d 117.8
(s, ipso-C), 129.4 (s, Ph), 132.1 (s, Ph), 134.2 (s, Ph), 142.0 (dm,
JC–F = 262 Hz, Ar-C), 144.2 (dm, JC–F = 267 Hz, Ar-C), 172.2 (s,
-141.3, (2F, dd, JF–F = 19.8, 8.5 Hz, F2, F5), -145.9 (2F, dd, JF–F
=
19.8, 8.5 Hz, F3, F4). IR (MeCN solution): 1676 cm-1 n(C O).
Concentration of this solution and attempts to isolate the product
resulted in decomposition to metallic gold.
C
O). 31P NMR (CDCl3, 121.5 MHz): d 32.3 (s). IR (powder):
1678 cm-1 n(C O). Anal. Found: C, 46.13; H, 2.30; N, 2.10. Calcd
for C26H15AuF4NO2P: C, 46.10; H, 2.23; N, 2.07%.
Synthesis of [(Ph3P)2Au][N(COB(C6F5)3)2C6F4] (11)
To a solution of 8a (204 mg, 0.30 mmol) and triphenylphosphine
(77 mg, 0.30 mmol) in dry diethyl ether (30 mL) was added at room
temperature B(C6F5)3·Et2O (346 mg, 0.60 mmol). The mixture was
stirred for 15 min, the solvent was removed and the yellow solid
residue recrystallised from a minimum amount of toluene layered
with light petroleum. Yellow crystals of 11 were obtained (452 mg,
Synthesis of (Cy3P)Au{N(CO)2C6F4} (8b)
Using the procedure described for 8a, the reaction yielded 8b as
colourless crystals (0.646 g, 0.82 mmol, 74%). The crystals grown
were suitable for single crystal X-ray analysis. 1H NMR (CDCl3,
300.1 MHz): d 1.23 (6H, br, m), 1.42 (12H, br, m), 1.70 (3H, br,
m), 1.85 (6H, br, m), 2.04 (6H, br, m). 19F NMR (CDCl3, 282.4
MHz) d -139.7 (2F, dd, JF–F = 19.8, 5.6 Hz, F2, F5), -146.4 (2F, dd,
1
0.23 mmol, 78%), suitable for single crystal X-ray analysis. H
NMR (CDCl3, 300.1 MHz): d 7.48 (30H, m, Ph). 19F NMR
(CDCl3, 282.4 MHz) d -115.9 (12F, t, JF–F = 22.4 Hz, o-F C6F5),
-133.5 (2F, br. s, F2, F5), -141.0 (2F, br. s, F3, F4), -158.2 (6F, t,
JF–F = 22.4 Hz p-F C6F5), -162.3 (12F, m, m-F C6F5). 31P NMR
1
JF–F = 19.8, 5.6 Hz, F3, F4). 13C{ H} NMR (CDCl3, 75.5 MHz): d
21.8–35.9 (8 signals, Cy), 141.8 (dm, JC–F = 258 Hz, Ar-C), 143.9
(dm, JC–F = 266 Hz, Ar-C), 172.5 (s, C O). 31P NMR (CDCl3,
1088 | Dalton Trans., 2011, 40, 1079–1090
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Table 2 Crystal and structure refinement data for compounds 2, 4, 5, 6 and 7
Compound
2
4
5
6·2MeCN
7·MeCN
Empirical formula
C8HF4NO2
C11H9F4NO2Si
C11H9F4NO2Sn
C20Ag2F8N2O4·
C4H6N2
734.0
Monoclinic
P21/c (no. 14)
7.93961(12)
26.9636(4)
10.48883(15)
90
105.245(2)
90
2166.43(5)
4
C8F4INO2·C2H3N
Formula weight
Crystal system
Space group
219.1
291.3
381.9
386.0
Monoclinic
P21/c (no. 14)
12.0520(5)
5.4998(2)
11.4291(4)
90
94.626(4)
90
755.09(5)
4
1.927
432
0.203
very pale yellow flat
prism
Monoclinic
P21/c (no. 14)
9.5135(8)
24.759(2)
10.7793(6)
90
91.391(6)
90
2538.3(3)
8
1.524
1184
0.231
colourless plate
Monoclinic
P21/c (no. 14)
19.1926(6)
6.6264(2)
20.1512(7)
90
90.257(3)
90
2562.76(14)
8
1.980
1472
2.039
colourless block
Monoclinic
P21/m (no. 11)
9.4073(7)
6.3030(5)
10.1518(10)
90
108.929(9)
90
569.39
˚
a/A
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
Volume/A
No. of formula units, Z
Calculated density/Mg m-3
F(000)
2
2.250
1408
1.915
colourless plate
2.252
364
2.865
colourless hexagonal
plate
Absorption coefficient m/mm-1
Crystal colour, shape
Crystal size/mm
q range/◦
0.60 ¥ 0.30 ¥ 0.06
0.30 ¥ 0.24 ¥ 0.06
0.22 ¥ 0.10 ¥ 0.06
0.47 ¥ 0.24 ¥ 0.12
0.18 ¥ 0.18 ¥ 0.01
3.4 to 25.0
3.1 to 20.0
3.4 to 30.0
3.3 to 27.5
3.6 to 25.0
Limiting indices
-14£ h £ 14, -6 £ k £ 6, -9 £ h £ 9, -23 £ k £ -27 £ h £ 27, -9 £ k -10 £ h £ 10, -35 £ k -11 £ h £ 11, -7 £ k £
-13 £ l £ 13
1.069 and 0.926
13776
23, -10 £ l £ 10
1.029 and 0.967
27063
£ 9, -28 £ l £ 28
1.112 and 0.873
48849
£ 35, -13 £ l £ 13
1.038 and 0.978
47568
7, -12 £ l £ 12
1.054 and 0.962
6985
Max. and min. transmission
Reflections collected (not
including absences)
No. of unique reflections, Rint
1334, 0.075
No. of ‘observed’ reflections (I > 1181
2357, 0.203
1262
7468, 0.070
5577
4974, 0.044
4481
1103, 0.104
902
2sI)
Data/restraints/parameters
1334/0/140
1.129
2357/0/343
0.869
7468/0/349
0.912
R1 = 0.029, wR2 =
0.056
4974/0/367
1.181
R1 = 0.025, wR2 =
0.050
1103/0/119
1.063
R1 = 0.057, wR2 =
0.116
Goodness-of-fit on F2
Final R indices (‘observed’ data) R1 = 0.044, wR2 = 0.097 R1 = 0.052, wR2 =
0.039
Final R indices (all data)
Largest diff. peak and hole/e A
R1 = 0.056, wR2 = 0.103 R1 = 0.145, wR2 =
R1 = 0.050, wR2 =
0.058
0.82 and -0.80
R1 = 0.031, wR2 =
0.051
0.65 and -0.53
R1 = 0.079, wR2 =
0.123
2.45 and -1.04
0.049
-3
˚
0.24 and -0.23
0.20 and -0.19
(CDCl3, 121.5 MHz) 30.1 (s). 11B NMR (CDCl3, 96.3 MHz): d
-2.7 (br). IR (nujol mull): 1545 cm-1 n(C O).
11 was measured at 120(2) K on a Bruker-Nonius KappaCCD
diffractometer (at the EPSRC National Crystallography Service).
Intensity data were measured by thin-slice w- and j-scans. Crystal
data and experimental details are collated in Table 2 and Table 3.
Data were processed using the CrysAlisPro-CCD and -RED22
programs, or for 11, the DENZO/SCALEPACK23 programs. The
structures were determined by the direct methods routines in
the SHELXS program24 and refined by full-matrix least-squares
methods, on F2¢s, in SHELXL24 In general, the non-hydrogen
atoms were refined with anisotropic thermal parameters, although
some atoms of disordered groups in compounds 9 and 11 did not
refine satisfactorily and were later treated isotropically. Hydrogen
atoms were included in idealised positions and their Uiso values
were set to ride on the Ueq values of the parent carbon atoms.
Refinement results are included in Table 2. Scattering factors for
neutral atoms were taken from reference 25. Computer programs
used in this analysis have been noted above, and were run through
WinGX26 on a Dell Precision 370 PC at the University of East
Anglia.
Synthesis of [Au(nb)3][N(COB(C6F5)3)2C6F4] (12)
To a mixture of 9 (50 mg, 0.10 mmol) and norbornene (94 mg,
1.00 mmol) in dry toluene (10 mL) cooled to 0 ◦C was added
tris(pentafluorophenyl)borane (130 mg, 0.25 mmol). The reaction
was left to stir at 0 ◦C for 1 h. The resulting solution was filtered
and the solvent was removed in vacuo to leave a yellow solid.
Recrystallisation in the minimum amount of dichloromethane
at -30 ◦C gave 12 as yellow crystals in moderate yield (92 mg,
0.05 mmol, 54%). The crystals were suitable for X-ray analysis. 1H
NMR (CDCl3, 300.1 MHz): d 0.94 (2H, d, JH–H = 9.7 Hz), 1.01
(2H, d, JH–H = 10.2 Hz), 1.23 (2H, dd, JH–H = 8.5, 2.0 Hz), 1.74 (2H,
d, JH–H = 8.5 Hz), 3.02 (2H, s), 5.72 ppm (2H, s). 19F NMR (CDCl3
282.4 MHz): d -114.2 (12F, t, JF–F = 19.6 Hz, o-F C6F5), -132.1
(2F, dd, JF–F = 19.7, 8.4 Hz, F2, F5), -141.3 (2F, dd, JF–F = 19.7,
8.4 Hz, F3, F4), -159.2 (6F, t, JF–F = 19.6 Hz, m-F C6F5), -165.4
(12F, m, p-F C6F5). 11B NMR (CDCl3, 96.3 MHz): d 1.9 (br).
Acknowledgements
X-Ray Crystallography
Crystals of compounds 2, 4, 5, 6·2MeCN, 7·MeCN, 8a, 8b,
9·toluene and 10·3MeCN were examined at 140(1) K on an Oxford
Diffraction Xcalibur-3/Sapphire3-CCD diffractometer, equipped
with Mo-Ka radiation and graphite monochromator; compound
We are grateful to Johnson Matthey plc for a loan of gold
compounds and the University of East Anglia for support of this
work. We thank Dr Mark Schormann for his assistance with the
X-ray crystallography.
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The Royal Society of Chemistry 2011
Dalton Trans., 2011, 40, 1079–1090 | 1089
©

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Table 3 Crystal and structure refinement data for compounds 8a, 8b, 9, 10 and 11
Compound
8a
8b·0.5 toluene
9·toluene
10·3MeCN
11
Empirical formula
C26H15AuF4NO2P
C26H33AuF4NO2P· C12H8AuF4NO2S C7H8 C20H6AgAuF8N4O4· C80H30AuB2F34NO2.
0.5(C7H8)
741.5
CH3CN
864.2
ca 1.5 (C4H8O)
2071.73
Formula weight
Crystal system
Space group
677.3
595.3
Monoclinic
P21/c (no. 14)
13.79281(11)
12.00838(11)
28.1090(3)
90
100.4139(10)
90
4578.99(7)
8
Triclinic
P1(no. 2)
Monoclinic
P21/c (no. 14)
11.8670(17)
23.7634(14)
6.6297(5)
90
90.071(9)
90
1869.6(3)
4
Triclinic
P1(no. 2)
Monoclinic
P21/n (no. 14)
15.4133(11)
32.505(2)
16.4236(12)
90
89.997(2)
90
8228.3(10)
4
¯
¯
˚
a/A
11.3527(8)
11.7282(9)
11.9341 (9)
74.895(6)
69.615(7)
72.833(6)
1400.86(18)
2
8.24928(9)
9.49150(15)
16.8812(3)
94.1577(13)
94.4125(11)
111.3597(12)
1220.12(3)
2
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
3
˚
Volume/A
No. of formula units, Z
Calculated density/Mg m-3
F(000)
1.965
2592
6.553
colourless plate
1.758
734
2.115
1136
2.352
812
1.672
4072
Absorption coefficient m/mm-1
Crystal colour, shape
5.363
8.034
colourless rod
6.911
colourless block
1.956
pale-yellow block
colourless block,
cut from prism
0.16 ¥ 0.15 ¥ 0.14
3.4 to 30.0
Crystal size/mm
q range/◦
Limiting indices
0.41 ¥ 0.38 ¥ 0.08
3.3 to 30.0
0.50 ¥ 0.04 ¥ 0.03
3.4 to 22.5
0.28 ¥ 0.18 ¥ 0.16
3.4 to 30.0
0.14 ¥ 0.09 ¥ 0.05
2.9 to 22.5
-19 £ h £ 19, -16 £ k -15 £ h £ 15, -16 £ -12 £ h £ 12, -25 £ k £ -11 £ h £ 11, -13 £ k -16 £ h £ 16, -34 £ k
£ 16, -39 £ l £ 39
1.325 and 0.497
117169
k £ 16, -16 £ l £ 16 25, -7 £ l £ 7
£ 13, -23 £ l £ 23
1.278 and 0.676
34701
£ 35, -17 £ l £ 17
1.000 and 0.651
37322
Max. and min. transmission
Reflections collected (not
including absences)
1.159 and 0.796
15566
1.177 and 0.827
18667
No. of unique reflections, Rint
13315, 0.071
8119, 0.043
7071
2437, 0.119
1759
7115, 0.041
6535
10292, 0.075
8628
No. of ‘observed’ reflections (I > 11064
2sI)
Data/restraints/parameters
13315/0/631
1.214
8119/0/362
1.051
R1 = 0.031, wR2 =
0.079
R1 = 0.038, wR2 =
0.083
2.79 and -3.68
2437/0/219
1.043
7115/12/390
1.042
10292/0/1145
1.036
R1 = 0.088, wR2 =
0.179
R1 = 0.111, wR2 =
0.1924
1.95 and -1.34
Goodness-of-fit on F2
Final R indices (‘observed’ data) R1 = 0.052, wR2 =
R1 = 0.052, wR2 = 0.091 R1 = 0.017, wR2 =
0.070
R1 = 0.072, wR2 =
0.074
0.041
R1 = 0.082, wR2 = 0.099 R1 = 0.021, wR2 =
0.042
Final R indices (all data)
-3
˚
Largest diff. peak and hole/e A
1.80 and -2.43
1.59 and -1.09
0.86 and -0.91
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1090 | Dalton Trans., 2011, 40, 1079–1090
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The Royal Society of Chemistry 2011
©