Gold complexes of ditelluridoimidodiphosphinate ligands - Reversible oxidation of Au(I) to Au(III) via insertion of gold into a phosphorus-tellurium bond

Article abstract of DOI:10.1139/V08-074

The reaction of (THT)AuCl with (TMEDA)Na[N(TePR₂)₂] (R = Ph, i-Pr, t-Bu) produces a series of gold (III) complexes of the type [{R₂PNP(Te)R₂}Au(μ-Te)]₂ (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) rather

Full text of DOI:10.1139/V08-074

39
Gold complexes of ditelluridoimidodiphosphinate
ligands — Reversible oxidation of Au(I) to Au(III)
via insertion of gold into a phosphorus–tellurium
bond1
Dana J. Eisler, Stuart D. Robertson, and Tristram Chivers
Abstract: The reaction of (THT)AuCl with (TMEDA)Na[N(TePR2)2] (R = Ph, i-Pr, t-Bu) produces a series of gold
(III) complexes of the type [{R2PNP(Te)R2}Au(µ-Te)]2 (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) rather than the ex-
pected homoleptic Au(I) complexes of the ditelluridoimidodiphosphinate ligands. A combination of solution- and solid-
state NMR studies shows that both cis and trans isomers of 4a–4c are formed in these reactions. X-ray structural deter-
minations of the trans isomers of 4a–4c reveal a centrosymmetric arrangement with a central four-membered Au2Te2
ring formed by the formal insertion of gold into a P–Te bond; this insertion process was shown to be reversible upon
addition of PPh3 to 4a to give the monomeric gold(I) complex Ph3PAu[N{TeP(i-Pr)2}2]. The X-ray structure of cis-4b
is also described.
Key words: gold, tellurium, redox, X-ray structures, imidodiphosphinate.
Résumé : La réaction du (THT)AuCl avec le (TMEDA)Na[N(TePr2)2] (R = Ph, i-Pr et t-Bu) conduit à la formation
d’une série de complexes d’or(III) du type [{R2PNP(Te)R2}Au(µ-Te)]2 (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) plutôt
qu’aux complexes homoleptiques Au(I) des ligands ditelluridoimidodiphosphinate. Une combinaison d’études RMN en
solution et à l’état solide a permis de montrer que dans ces réactions il y a formation des isomères cis- et trans- des
produits 4a–4c. Des déterminations de structures par diffraction des rayons X des isomères trans- des produits 4a–4c
indiquent qu’ils existent dans un arrangement centrosymétrique, avec un cycle central à quatre membres de Au2Te2 ob-
tenu par l’insertion formelle d’or dans la liaison P-Te; on a démontré que ce processus d’insertion est réversible par
addition de PPh3 au produit 4a qui conduit à la formation du complexe monomère d’or(I), Ph3PAu[N{TeP(i-Pr)2}2].
On décrit aussi la structure du produit cis-4b telle que déterminée par diffraction des rayons X.
Mots-clés : or, tellure, redox, structures déterminées par diffraction des rayons X, imidodiphosphinate.
[Traduit par la Rédaction] Eisler et al. 46
Introduction
discovery of a synthesis of alkali-metal derivatives of the
ditellurido derivatives 1a–1c (5–7). The latter development
has opened the door to investigations of the fundamental
chemistry of these tellurium-containing ligands, as well as
applications of their metal complexes as single-source pre-
cursors for binary metal tellurides that are of interest for use,
inter alia, in solar cells (CdTe, HgTe) or infrared detectors
(SnTe), and as thermoelectric materials (Sb2Te3, Bi2Te3) (8).
Prior to 2002, the chemistry of dichalcogenidoimidodi-
phosphinate ligands of the type 1 was restricted to deriva-
tives in which E = O, S, or Se. A number of uses or potential
uses for metal complexes of these inorganic analogues of
acetylacetonates have been identified in review articles (1–
3), e.g., as luminescent materials or lanthanide shift re-
agents, as well as in metal extraction processes. In the last
5–6 years, a renaissance of the interest in such metal com-
plexes has occurred as a result of (i) extensive studies by
O’Brien and co-workers, which have demonstrated that
metal complexes of the selenium analogue of 1a are suitable
single-source precursors for the deposition of pure thin films
of metal selenides by using CVD techniques (4) and (ii) the
Received 10 March 2008. Accepted 10 April 2008. Published on the NRC Research Press Web site at http://canjchem.nrc.ca on
11 June 2008.
Dedicated to Professor Dick Puddephatt in recognition of his outstanding contributions to chemistry in Canada.
D.J. Eisler, S.D. Robertson, and T. Chivers.2 Department of Chemistry, University of Calgary, Calgary, AB T2N 1N4, Canada.
1This article is part of a Special Issue dedicated to Professor R. Puddephatt.
2Corresponding author (e-mail: chivers@ucalgary.ca).
Can. J. Chem. 87: 39–46 (2009)
doi:10.1139/V08-074
© 2008 NRC Canada

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Can. J. Chem. Vol. 87, 2008
Scheme 1.
Investigations of the redox behaviour of 1a revealed new
aspects of the well-studied chemistry of dichalcogenido-
imidodiphosphinate ligands in which one-electron oxida-
tion with iodine produces the dimeric ditelluride
TePR2NR2PTe–TePR2NPR2Te (2: R = i-Pr) (see Scheme 1)
with an elongated central tellurium–tellurium bond (9). Sim-
ilar dichalcogenides are also obtained upon oxidation of the
disulfido and diselenido ligands (1: E = S, R = t-Bu; E = Se,
R = i-Pr, t-Bu) (7). In the case of 1c, however, a structural
isomer comprised of a contact ion pair in which a [(TeP-t-
Bu2)2N]– anion is Te, Te chelated to one Te atom of an in-
cipient cyclic cation [(TeP-t-Bu2)2N]+ is obtained (7). The
five-membered cations [(EPR2)2N]+ (E = S, Se, Te; R = i-Pr,
t-Bu) are obtained, as iodide salts, by two-electron oxidation
of the corresponding anions with iodine (7, 10).
Another fascinating difference between the behaviour of
the ditellurido ligand 1a and the dithio or diselenido ana-
logues (1: E = S, Se; R = i-Pr) is observed in the reactions
with group 13 dihalides (21). For example, the reaction of
GaCl3 with 3 equiv. of Na(TMEDA)1a produces the dimeric
complex {Ga(µ-Te)[i-Pr2P(Te)NPi-Pr2]}2 (3) as a mixture of
cis and trans isomers, together with a high yield of the
ditelluride 2. As indicated in Scheme 1, the formation of the
four-membered Ga2Te2 ring in 3 was proposed to occur via
initial formation of the homoleptic gallium(III) complex
Ga[N{TeP(i-Pr)2}]3, followed by reductive elimination and
formation of the gallium(I) complex Ga[N{TeP(i-Pr)2}] (2).
Subsequent rearrangement of this Ga(I) complex to the cor-
responding gallatellurone followed by dimerisation gives 3
in which the gallium centres are P, Te-chelated by the
monotellurido [TePR2PNPR2]– (R = i-Pr) ligand. The syn-
thesis of the lithium derivative of this anion and its use as an
in situ reagent for the preparation of homoleptic complexes
of group 12 metals has been reported recently (22).
To determine whether a more labile two-electron donor
than PPh3 would allow the formation of oligomeric gold
complexes of ditelluridoimidodiphosphinate ligands similar
to those observed for Cu(I) and Ag(I) (13), we have investi-
gated the reactions of the sodium salts of 1a–1c with the
soluble gold(I) complex (THT)AuCl (THT = tetrahy-
drothiophene). Interestingly, these reactions give rise to the
formation of the gold (III) complexes [{R2PNP(Te)R2}Au(µ-
Te)]2 (4a, R = i-Pr; 4b, R = Ph; 4c, R = t-Bu) rather than the
expected homoleptic Au(I) complexes of 1a–1c. The charac-
terisation of these new gold(III) complexes in the solid state
by X-ray structural determinations and 31P NMR spectros-
copy (4a) and in solution by multinuclear (1H, 31P, and
125Te) NMR spectroscopy is discussed.
Homoleptic complexes of 1a with group 12 (Zn, Cd, Hg)
and group 15 (Sb, Bi) metals are obtained via metathesis
with the appropriate metal halide (6), and the cadmium and
antimony complexes have been shown to be effective single-
source precursors for pure CdTe (11) and Sb2Te3 (12) thin
films, respectively, using the technique of aerosol-assisted
chemical vapour deposition (AACVD) (8). Homoleptic com-
plexes may also be prepared for coinage metals, although the
ditellurido ligands 1a and 1b give rise to higher oligomers
with silver(I) (specifically, a hexamer for 1a and a tetramer
for 1b) (13) compared to the trimeric complexes observed
for 1 (E = S, Se; R = i-Pr) (14). Interestingly, the ditellurido
ligands in both copper(I) and silver(I) complexes exhibit the
ability to act as doubly bridging ligands, a feature that brings
two metal centres in close proximity suggesting the possibil-
ity of metallophilic (d10–d10) interactions. The strong reduc-
ing power of 1a is evident in the reaction of the sodium salt
with AuCl, which immediately deposits a gold mirror; how-
ever, this reduction may be pre-empted by the addition of
PPh3, leading to the isolation of the monomeric gold(I)
complex Ph3PAu[N{TeP(i-Pr)2}2] (13). Although tellurium
occurs in combination with gold in certain minerals (e.g.,
krennerite, AuTe2), only a few gold–tellurium complexes
have been structurally characterized. Some representative
examples include the ternary gold tellurium halides AuTeI
(15) and AuTe2X (X = Cl, I) (16), the tetrameric gold(I)
tellurolate Au4[TeC(SiMe3)3]4 (17), the monomeric gold(I)
tellurolate Ph3PAu[TeC(SiMe3)3] (17), and a variety of
Results and discussion
The 1:1 reaction of the ditelluridoimidodiphosphinate an-
ions 1a–1c, as their sodium salts, with (THT)AuCl proceeds
rapidly in dichloromethane at room temperature producing
deeply coloured solutions of the gold complexes 4a–4c, as
depicted in Scheme 2. While the iso-propyl complex 4a is
moderately soluble in THF and CH2Cl2, the phenyl and tert-
butyl derivatives 4b and 4c exhibit poor solubility in com-
mon organic solvents. The complexes 4a–4c were all ob-
tained in high purity as crystalline solids, which are stable to
4–
3–
binary gold–tellurium anions, e.g. Au4Te4 (18), Au3Te4
(19), and AuTe7 (20).
3–
© 2008 NRC Canada

Eisler et al.
41
Scheme 2.
light, air, and moisture in the solid state, but decompose
slowly (weeks) in solution at room temperature. The purity
of the bulk crystalline samples was confirmed in each case
by elemental analysis.
Fig. 1. Thermal ellipsoid diagram of complex trans-4b. Hydro-
gen atoms have been removed for clarity. Symmetry transforma-
tions used to generate equivalent atoms: –x, –y, –z.
X-ray diffraction studies were carried out on crystalline
samples of all three complexes 4a–4c. The most significant
difference between the structures involves the substituents
on the phosphorus centres, and so the structure of trans-4b
is shown in Fig. 1 as a representative example; a selection of
geometrical parameters is given in Table 1. In each case, it
was found that the complexes adopt a dimeric structure,
which is comprised of a central [Au2Te2]2+ four-membered
ring bound to two monotelluridoimidodiphosphinate anions
[R2P(Te)NPR2]– (22) that are arranged in a trans fashion
(Fig. 1). A similar structure has been observed previously in
the gallium complex 3 (Scheme 1), although in that case, the
metal centres are tetrahedral, whereas the gold centres in the
complexes 4a–4c are approximately square-planar.
Table 1. Selected bond distances and angles for trans-4a, trans-
4b, and trans-4c.
trans-4a
trans-4b
trans-4c
The solid-state structures of the complexes 4a–4c clearly
indicate that the gold centres have been oxidized from Au(I)
to Au(III). This oxidation formally involves insertion of
Au(I) into a phosphorus–tellurium bond of the ditellurid-
oimidodiphosphinate ligand, with concomitant reduction of
one of the P(V) centres to P(III). Oxidation of Au(I) to
Au(III) with reagents such as alkyl halides and halogens is
well-documented and known to be facile (23). Oxidation by
chalcogens has been observed before in the reaction of
AuCN with Na2Se5, which produced [Au2Se2(Se4)2]2– (24)
containing an Au2Se2 ring similar to the central Au2Te2 ring
observed in the complexes 4a–4c. However, the current work
appears to be the only example of the oxidation of Au(I) to
Au(III) by insertion into a phosphorus–chalcogen bond. The
formation of the Au2Te2 ring in 4a–4c, presumably via the
initial production of a gold(I) complex of 1a–1c, parallels
the transformation depicted in Scheme 1 for the generation
of a Ga2Te2 ring, except that the Ga(I) complex is generated
by reductive elimination rather than an initial metathesis.
As expected for Au(III) (d8 configuration), the geometry
at the gold centres is square-planar, although there are sig-
nificant deviations from the ideal 90° angles, which likely
arise from the softness of the Au–P and Au–Te bonds (Ta-
ble 1). Regardless of the deviation from the ideal angles, the
sum of the bond angles is near 360° for all three complexes
(trans-4a, 359.93°; trans-4b, 360.60°; trans-4c, 359.81°). In
each case, the most acute angle is the endocyclic Te(2)–
Au(1)–Te(2A) angle [trans-4a, 78.34(4)°; trans-4b,
79.18(2)°; trans-4c, 74.75(4)°], while the widest angles are
those involving P(2)–Au(1)–Te(2) [trans-4a, 98.95(7)°;
trans-4b, 97.43(4)°; trans-4c, 104.66(6)°]. The increase in
Distances [Å]
Au1—P2
Au1—Te1
Au1—Te2
Au1—Te2A
P1—Te1
P1—N1
P2—N1
Te2—Te2A
2.365(3)
2.625(1)
2.628(1)
2.644(1)
2.456(3)
1.588(8)
1.630(7)
3.330(8)
2.357(2)
2.6197(8)
2.6149(8)
2.6446(9)
2.464(2)
1.583(5)
1.621(5)
3.352(7)
2.377(2)
2.6267(9)
2.649(1)
2.6334(8)
2.474(2)
1.589(6)
1.634(6)
3.2067(9)
Angles [°]
P2–Au1–Te1
P2–Au1–Te2
Te1–Au1–Te2A
Te2–Au1–Te2A
P2–Au1–Te2A
Te1–Au1–Te2
Au1–Te2–Au1A
93.82(7)
98.95(7)
88.82(4)
78.34(4)
177.23(6)
166.05(3)
101.66(3)
92.14(4)
97.43(4)
91.85(3)
79.18(2)
173.79(4)
168.43(2)
100.82(2)
94.91(6)
104.66(6)
85.49(4)
74.75(4)
176.96(5)
160.02(2)
105.25(2)
this latter angle, and compression of the former angles,
correlates with an increase in the bulk of the substituents on
the phosphorus centres, and may arise from unfavourable
steric interactions between these groups and the central
Au2Te2 ring. The Au–Te–Au angles in the planar four-
membered Au2Te2 ring in trans-4a–4c are larger than the
corresponding Te–Au–Te angles by 23.3–30.5° leading to
transannular distances of 3.20–3.35 Å that are well within
the sum of van der Waals radii for two tellurium atoms
(4.40 Å). For comparison, the Te—Te separation in the four-
© 2008 NRC Canada

42
Can. J. Chem. Vol. 87, 2008
Table 2. Selected bond distances and
Fig. 2. Thermal ellipsoid diagram for one of the two crystallo-
graphically independent molecules of the complex cis-4b. Hydro-
gen atoms have been removed for clarity.
angles for cis-4b, molecule 1.
Distances [Å]
Au1—P2
Au1—Te1
Au1—Te3
Au2—Te3
P1—Te1
P1—N1
2.345(4)
2.627(2)
2.645(1)
2.655(2)
2.458(5)
1.58(2)
P3—N2
1.60(1)
Te2—Te3
Au2—P3
Au1—Te2
Au2—Te2
Au2—Te4
P4—Te4
P2—N1
3.347(2)
2.357(5)
2.612(2)
2.620(2)
2.634(2)
2.461(5)
1.61(2)
membered Au2Te2 rings in AuTeI is 3.235 Å (15). The
Au—Te bond lengths fall in a very narrow range for all
three complexes [2.6149(8)–2.649(1) Å] and are similar to
other reported Au–Te distances (14–20).
P4—N2
1.61(2)
Angles [°]
P2–Au1–Te1
P2–Au1–Te2
Te1–Au1–Te3
Te2–Au1–Te3
Te2–Au1–Te1
P2–Au1–Te3
Au1–Te2–Au2
P3–Au2–Te–4
P3–Au2–Te2
Te3–Au2–Te4
Te2–Au2–Te3
Te2–Au2–Te4
P3–Au2–Te3
Au1–Te3–Au2
93.3(1)
98.1(1)
During this work, it was found that rapid crystallization of
4b from concentrated THF or CH2Cl2 solutions resulted in
the formation of two distinct crystal morphologies: deep red,
rhombohedral plates and orange rectangular plates, the latter
of which were identified as trans-4b by determination of the
unit cell. An X-ray crystallographic study on a rhombohedral
plate revealed the presence of the cis isomer of complex 4b
(Fig. 2). There are two crystallographically independent, but
chemically equivalent, molecules of cis-4b present in the
asymmetric unit, which have very similar metrical parame-
ters.
The geometrical parameters of cis-4b are similar to those
observed for trans-4b. The geometry of the gold(III) centres
is best described as distorted square-planar, with significant
deviations from the ideal 90° bond angles (Table 2). The
most compressed angles are those contained within the cen-
tral Au2Te2 ring [Te2–Au1–Te3, 78.60(5)°; Te2–Au2–Te3,
78.28° (5)], while the widest angles are P2–Au1–Te2,
98.1(1)° and P3–Au2–Te2, 96.2(1)°. The Au–Te bond dis-
tances [range: 2.612(2)–2.655(2) Å] are similar to those ob-
served in the trans complexes of 4a–4c. Like the trans
complexes of 4a–4c, the four-membered Au2Te2 ring of cis-
4b is planar, with the Au–Te–Au bond angles more than 20°
larger than the Te–Au–Te angles. As a consequence, the
transannular Te–Te distance is 3.35 Å, which is virtually
identical to that of trans-4b. Regardless of the similarity be-
tween the cis and trans structures, there is a clear preference
in the solid state for the trans isomer. Slow crystallization of
all of the complexes 4a–4c consistently resulted in the isola-
tion of the trans isomer in the solid state; only a single crys-
tal morphology was observed and random testing of multiple
crystals from each sample using X-ray crystallography
provided exclusively the unit cell for the trans isomer. All at-
tempts to isolate crystals of cis-4a and cis-4c were unsuc-
cessful.
90.73(5)
78.60(5)
166.40(4)
173.8(1)
100.23(4)
92.8(1)
96.2(1)
93.77(5)
78.28(5)
166.67(5)
171.4(1)
102.03(5)
cal shifts and coupling constants, were observed in each
case. However, the two species were not present in equal
quantities, but in a ratio of nearly 2:1 in each case. The ob-
served spectroscopic data can be explained by the presence
of both the cis and trans isomers in solution, with one iso-
mer clearly predominating. While it is tempting to assign the
resonances of the major component present in solution to the
trans isomer, solid-state NMR studies suggest that it is the
cis isomer that predominates in solution.
The solid-state 31P NMR spectrum of a crystalline sample
of 4a grown slowly from dichloromethane is compared with
the solution-state spectrum in Fig. 3. It is clear from these
two spectra that the isomer that predominates in the solid
state is, in fact, the minor component present in solution.
The unit cell was determined for multiple crystals from this
solid-state sample, and in each case the presence of the trans
isomer was confirmed. It should be noted that the solid-state
31P NMR spectrum indicates that there is a small quantity of
the cis isomer present in the sample. Nonetheless, crystals of
the cis isomer could not be detected visually or by crystallo-
graphic methods. In contrast, the solid-state 31P NMR spec-
trum obtained on a sample of 4b that had been rapidly
crystallized showed that the ratio of the two isomers was
largely unchanged from that present in solution. This obser-
The solution-state NMR spectra obtained for the com-
plexes 4a–4c revealed the presence of two closely related
species in solution. For example, in the 31P NMR spectra,
two sets of phosphorus resonances, with very similar chemi-
© 2008 NRC Canada

Eisler et al.
43
Fig 3. (Top) Solution 31P NMR spectrum of complex 4a showing the mixture of cis and trans isomers. (Bottom) Solid-state 31P NMR
spectrum (11 kHz) of slowly crystallized 4a.
Scheme 3.
Conclusions
vation, in conjunction with the relative quantities of crystals
of cis- and trans-4b noted in rapidly crystallized samples,
also suggests that it is the cis isomer that is the major com-
ponent in solution. Although it is possible that the trans iso-
mer crystallizes preferentially, leaving the cis isomer in
solution, the 31P NMR spectrum obtained for a single crystal
of trans-4a was found to be identical to that of bulk samples
of 4a, with the two sets of resonances in a 2:1 intensity ra-
tio. Thus, it is clear that the cis and trans isomers are readily
able to interconvert in solution, although the mechanism by
which this occurs is not clear.
The reaction of the soluble Au(I) complex (THT)AuCl
with the ditelluridoimidodiphosphinate complexes 1a–1c
was found to produce the stable dimeric complexes 4a–4c,
in which the gold centres have been oxidized to Au(III).
This oxidation involves the formal insertion of the gold
centres into a phosphorus–tellurium bond and converts a
ditelluridoimidodiphosphinate ligand to a monotellurido-
imidodiphosphinate with the formation of an Au2Te2 ring.
The insertion of a metal centre into a P–Te bond has been
observed previously in the formation of the gallium complex
{Ga(µ-Te)[iPr2P(Te)NPiPr2]}2 (3). Taken together, these re-
sults indicate that reactions of the ditellurido ligands 1a–1c
with metals that have two easily accessible oxidation states,
separated by two units, may be complicated by redox chem-
istry. The reversibility of the redox chemistry that was ob-
served in the current work is unprecedented and may have
significant implications in the formation of metal complexes
of ditelluridoimidodiphosphinate ligands; in particular, an in-
vestigation of the possible occurrence of a similar process
for the gallium(III) complex 3 is warranted.
Finally, we note a minor difference in the 31P NMR spec-
tra of the cis and trans isomers. The trans isomers exhibit
one set of mutually coupled doublets, whereas the reso-
nances for the cis isomers exhibit second-order behaviour
and appear as more complex multiplets, as observed for the
related square-planar complexes cis-[M{Ph2P(E)NPPh2}2]
(M = Pd, Pt; E = S, Se) (25).
In light of the facile oxidation of Au(I) to Au(III) ob-
served in this work and the previous observation that Ph3P
stabilizes a homoleptic Au(I) complex of 1a (13), we de-
cided to investigate the reaction of 4a with Ph3P. Addition of
Ph3P to solutions of 4a resulted in the immediate and quanti-
tative formation of the known complex Ph3PAu[N{TeP(i-
Pr)2}2] (13), which was identified by 31P NMR spectroscopy
(Scheme 3). To further confirm the identity of the complex,
it was shown that the addition of an authentic sample of
Ph3PAu[N{TeP(i-Pr)2}2] to the solution used to obtain the
NMR spectrum resulted only in an increase in the intensity
of the NMR resonances; no additional resonances were ob-
served.
Experimental section
Reagents and general procedures
Solvents were dried and distilled before use: n-hexane,
THF, and toluene (Na/benzophenone); CH2Cl2 (calcium hy-
dride). The ditelluridoimidodiphosphinate complexes 1a (6),
1b (5), and 1c (7) and the complex (THT)AuCl (26) were
prepared according to the literature procedures. The han-
dling of air- and moisture-sensitive materials was performed
© 2008 NRC Canada

44
Can. J. Chem. Vol. 87, 2009
under an atmosphere of argon gas using standard Schlenk
sulting in the immediate formation of a dark red solution.
The mixture was stirred for 15 min and then filtered through
Celite. The solution was concentrated to ~30 mL and stored
at –30 °C for 72 h giving crystalline 4c (0.080 g, 0.05 mmol,
1
techniques or a glovebox. H, 31P, and 125Te NMR spectra
were collected using a Bruker AC-300, AMX-300, or DRX-
400 spectrometer, and chemical shifts are reported relative
to Me4Si (1H), 85% H3PO4 (31P), and Te2Ph2 (125Te). Solid-
state 31P NMR spectra were collected on a Bruker AM300
wide-bore spectrometer in a 4 mm tube, and chemical shifts
are reported relative to (NH4)H2PO4. The Analytical Ser-
vices Laboratory of the Department of Chemistry, Univer-
sity of Calgary, provided elemental analyses.
1
34%). H NMR (CD2Cl2) δ: 1.39, (m, C(CH3)3, cis-4c), 1.18
(m, C(CH3)3, trans-4c). 31P NMR (CD2Cl2) δ: 129.17 (m,
2
PAu, cis-4c), 124.14 (d, JPP = 27 Hz, PAu, trans-4c), 94.71
2
1
(d, JPP = 27 Hz, JTeP = 980 Hz, PTe, trans-4c), 94.02
1
(m, JTeP = 980 Hz, PTe, cis-4c). Anal. calcd. for
C32H72Au2N2P4Te4 (%): C 25.40, H 4.80, N 1.85; found: C
25.43, H, 4.48, N 1.75. X-ray quality crystals of trans-4c
were grown by slow evaporation of a solution of the com-
plex in CH2Cl2.
Preparation of [(i-Pr2PNP(Te)i-Pr2)Au(␮-Te)]2 (4a)
A solution of 1a (0.200 g, 0.31 mmol) in CH2Cl2 (25 mL)
was added to a darkened flask containing a solution of
(THT)AuCl (0.100 g, 0.31 mmol) in CH2Cl2 (15 mL), re-
sulting in the immediate formation of a dark red solution.
The mixture was stirred for 15 min and then filtered through
Celite. The solution was stored at –30 °C for 72 h giving
dark red crystals of 4a, suitable for X-ray analysis (0.158 g,
0.11 mmol, 73%). 1H NMR (D8-THF) δ: 2.35 (m (CH3)2CH,
trans-4a), 2.25 (m, (CH3)2CH, cis-4a), 1.23 (m, (CH3)2CH,
cis-4a, trans-4a). 31P NMR (D8-THF) δ: 113.94 (m, PAu,
X-ray structural analyses
Crystal data for trans-4a, trans-4b, cis-4b, and trans-4c
are summarized in Table 3.3 A suitable crystal of the com-
plex was selected, coated in Paratone oil, and mounted on a
glass fibre. Data were collected at 173 K (273 K = 0 °C) on
a Nonius Kappa CCD diffractometer using Mo Κα radiation
(λ = 0.71073 Å) via ω and φ scans. The unit-cell parameters
were calculated and refined from the full data set. Crystal
cell refinement and data reduction were carried out using the
Nonius DENZO package. After data reduction, the data were
corrected for absorption using SORTAV (27). The structures
were solved using the automated Patterson routine within
SHELXS-97 (28) and refinement was carried out on F2
against all independent reflections by the full-matrix least-
squares method using the SHELXL-97 program (29). The
hydrogen atoms were calculated geometrically and were rid-
ing on their respective atoms unless otherwise noted. For the
complexes trans-4a, trans-4b, and trans-4c, all non-
hydrogen atoms were refined with anisotropic thermal pa-
rameters. In each case, only one-half of the molecule was lo-
cated in the difference Fourier map as the molecule is
situated around a centre of symmetry. In the case of complex
cis-4b, the crystals diffracted weakly, and so a relatively
poor-quality dataset was obtained. The complex crystallizes
with two chemically equivalent, but crystallographically in-
dependent, molecules in the asymmetric unit. Four of the
phenyl substituents were disordered and each was modelled
as an isotropic 50:50 mixture with geometric restraints; all
other phenyl rings were constrained to be regular hexagons
and were refined with isotropic thermal displacement param-
eters. The lattice-bound THF molecules were poorly or-
dered, and each was modelled as an isotropic 50:50 mixture
with geometric restraints. Due to the low quality of the data,
only the Au, Te, P, and N atoms making up the core of the
structure were refined with anisotropic thermal displacement
parameters.
2
cis-4a), 108.88 (d, JPP = 29 Hz, PAu, trans-4a), 80.70 (d,
2JPP = 29 Hz, 1JTeP = 946 Hz, PTe, trans-4a), 79.15 (m, 1JTeP
=
=
1
948 Hz, PTe, cis-4a). 125Te NMR δ: 292.0 (d, JTeP
1
950 Hz, PTe, trans-4a), 281.0 (d, JTeP = 943 Hz, PTe, cis-
4a), –38.4 (s, µ-Te, trans-4a), –397.4 (s, µ-Te, cis-4a). Solid-
state 31P NMR δ: 116.17 (PAu, cis-4a), 106.15 (PAu, trans-
4a), 82.27 (PTe, trans-4a), 78.28 (PTe, cis-4a). Anal. calcd.
for C24H56Au2N2P4Te4 (%): C 20.58, H 4.03, N 2.00; found:
C 21.06, H, 3.94, N 1.95.
Preparation of [(Ph2PNP(Te)Ph2)Au(␮-Te)]2 (4b)
A solution of 1b (0.243 g, 0.31 mmol) in CH2Cl2 (25 mL)
was added to a darkened flask containing a solution of
(THT)AuCl (0.100 g, 0.31 mmol) in CH2Cl2 (15 mL), re-
sulting in the immediate formation of a dark green solution.
The mixture was stirred for 15 min and then filtered through
Celite, concentrated to ~15 mL and then stored at –30 °C for
1
24 h giving crystalline 4b (0.112 g, 0.07 mmol, 43%). H
NMR (D8-THF) δ: 7.69, 7.35 (m, Phenyl-H; cis-, trans-4b).
31P NMR (CD2Cl2) δ: 78.29 (m, PAu, cis-4b), 70.21 (d, 2JPP
=
1
80 Hz, PAu, trans-4b), 30.41 (m, JTeP = 982 Hz, PTe, cis-
2
1
4b), 30.22 (d, JPP = 80 Hz, JTeP = 982 Hz, PTe, trans-4b).
Anal. calcd. for C48H40Au2N2P4Te4 (%): C 34.46, H 2.41, N
1.67; found: C 34.56, H, 2.19, N 1.61. X-ray quality crystals
of trans-4b were grown by slow evaporation of a solution of
the complex in CH2Cl2. A suitable crystal for X-ray analysis
of the complex cis-4b was obtained from a concentrated so-
lution of the complex in THF.
Preparation of [(t-Bu2PNP(Te)t-Bu2)Au(␮-Te)]2 (4c)
A solution of 1c (0.218 g, 0.31 mmol) in CH2Cl2 (30 mL)
was added to a darkened flask containing a solution of
(THT)AuCl (0.100 g, 0.31 mmol) in CH2Cl2 (30 mL), re-
Acknowledgements
We thank Jamie Ritch for collection of the X-ray data for
the complex cis-4b and the Natural Sciences and Engi-
3 Supplementary data for this article are available on the journal Web site (canjchem.nrc.ca) or may be purchased from the Depository of
Unpublished Data, Document Delivery, CISTI, National Research Council Canada, Ottawa, ON K1A 0R6, Canada. DUD 3762. For more
information on obtaining material, refer to cisti-icist.nrc-cnrc.gc.ca/irm/unpub_e.shtml. CCDC 680164–680167 contain the crystallographic
data for this manuscript. These data can be obtained, free of charge, via www.ccdc.cam.ac.uk/conts/retrieving.html (Or from the Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax +44 1223 336033; or deposit@ccdc.cam.ac.uk).
© 2008 NRC Canada

Eisler et al.
45
Table 3. Crystallographic data for complexes trans-4a, trans-4b, cis-4b, and trans-4c.
Crystal
trans-4a
trans-4b
cis-4b
trans-4c
Empirical formula
C24H56Au2N2P4Te4
C48H40Au2N2P4Te4
C48H40Au2N2P4Te4@(C4H8O)
C32H72Au2N2P4Te4
Formula mass
Colour, habit
Crystal size (mm)
Crystal system
Space group
Z
1400.92
1673.03
1745.14
1513.13
Red, block
0.14 × 0.14 × 0.08
Triclinic
P-1
1
Orange, plate
0.08 × 0.06 × 0.04
Triclinic
P-1
1
Red, plate
0.10 × 0.08 × 0.04
Triclinic
P-1
4
Orange, plate
0.10 × 0.08 × 0.05
Triclinic
P-1
1
a (Å)
b (Å)
c (Å)
α (°)
β(°)
γ (°)
8.1864(7)
9.7477(8)
13.901(1)
108.625(5)
92.495(4)
112.270(3)
–9 ≤ h ≤ 9
–11 ≤ k ≤ 11
–16 ≤ l ≤ 16
955.49(14)
2.435
9.8966(2)
11.0948(3)
12.5300(4)
105.451(2)
93.450(2)
110.369(2)
–12 ≤ h ≤12;
–14 ≤ k ≤ 14;
–16 ≤ l ≤ 16
1225.23(6)
2.267
12.1688(3)
19.5417(5)
24.6410(6)
108.317(1)
90.033(2)
102.362(1)
–12 ≤ h ≤12;
–20 ≤ k ≤ 20;
–25 ≤ l ≤ 25
5419.2(2)
2.139
8.3382(5)
11.2270(5)
13.6625(9)
72.509(3)
76.957(3)
70.899(3)
–10 ≤ h ≤ 10;
–14 ≤ k ≤ 14;
–17 ≤ l ≤ 17
1141.13(12)
2.202
Collection ranges
Volume (Å3)
Dcalcd. (Mg/m3)
µ (mm–1)
F(000)
10.846
640
8.480
768
7.675
3232
9.090
704
θ range for data collection (°)
Observed reflections
Independent reflections
3.15–25.03
13619
3349 (Rint = 0.092)
2.57–27.50
22307
5603 (Rint = 0.070)
2.62–21.97
81792
13210 (Rint = 0.105)
2.76–26.37
18224
4659 (Rint = 0.093)
Data/restraints/ parameters
Maximum shift/error
3349/0/171
0.00
1.046
0.0440, 0.1005
0.0598, 0.1089
1.519 and –3.275
5603/0/271
0.00
1.030
0.0367, 0.0745
0.0554, 0.0817
1.046 and –2.216
13210/125/604
0.00
1.041
0.0531, 0.1125
0.0925, 0.1298
2.194 and –1.953
4659/0/211
0.00
1.035
0.0445, 0.0983
0.0703, 0.1106
1.251 and –3.497
GooF on F2
Final R indices [I > 2σ(I)]a
R indices (all data)b
Largest diff. peak and hole (e Å–3)
aR1 = [Σ||Fo|–|Fc2||]/[Σ|Fo|] for [I > 2σ (I)].
2
bwR2 = {[Σw(Fo –Fc2)2]/[Σw(Fo )2]}1/2 (all data).
9. T. Chivers, D.J. Eisler, J.S. Ritch, and H.M. Tuononen. Angew.
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1634 (2006); (b) J. Konu, T. Chivers, and H.M. Tuononen.
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support.
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