Angular arenediethynyl complexes of gold(I)

Article abstract of DOI:10.1021/om0000461

Alkynylgold(I) complexes have been prepared from the angular bis(alkyne) MeC₆H₃-3,5-(CCH)₂, in which the alkyne units are rigidly fixed at an angle of 120° to each other. Reaction with [AuCl(SMe₂)] and base yields the shock-sensitive, insoluble compound [{MeC₆H₃-3,5-(CCAu)₂}_n] (2), which reacts with isocyanide, phosphine, or phosphite ligands (L) to give [MeC₆H₃-3,5-(CCAuL)₂] (3; L = P(OPh)₃, P(OMe)₃, PPh₃, PMePh₂, t-BuNC, MeNC). The complexes with L = P(OMe)₃, PMePh₂ exist in the solid state as infinite one-dimensional ribbon structures in which neighboring molecules are associated through secondary gold-gold bonding. Complexes with diisocyanide ligands 1,4-C₆R₄(NC)₂ (R = H, Me) have the formula [{MeC₆H₃-3,5-(CCAu)₂(μ-LL)}_n] and are insoluble in organic solvents; they are suggested to have a zigzag polymeric structure. In contrast, complexes with diphosphine ligands (CH₂)_n(PPh₂)₂ (n = 1-6) are soluble and are suggested to be the cyclic tetragold(I) complexes of formula [{MeC₆H₃-3,5-(CCAu)₂(μ-LD)}₂]; the ring size varies from 24 to 34, depending on n.

Full text of DOI:10.1021/om0000461

2194
Organometallics 2000, 19, 2194-2199
An gu la r Ar en ed ieth yn yl Com p lexes of Gold (I)
Mary-Anne MacDonald and Richard J . Puddephatt*
Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7
Glenn P. A. Yap
Department of Chemistry, University of Ottawa, Ottawa, Canada K1N 6N5
Received J anuary 20, 2000
Alkynylgold(I) complexes have been prepared from the angular bis(alkyne) MeC6H3-3,5-
(CCH)2, in which the alkyne units are rigidly fixed at an angle of 120° to each other. Reaction
with [AuCl(SMe2)] and base yields the shock-sensitive, insoluble compound [{MeC6H3-3,5-
(CCAu)2}n] (2), which reacts with isocyanide, phosphine, or phosphite ligands (L) to give
[MeC6H3-3,5-(CCAuL)2] (3; L ) P(OPh)3, P(OMe)3, PPh3, PMePh2, t-BuNC, MeNC). The
complexes with L ) P(OMe)3, PMePh2 exist in the solid state as infinite one-dimensional
ribbon structures in which neighboring molecules are associated through secondary gold-
gold bonding. Complexes with diisocyanide ligands 1,4-C6R4(NC)2 (R ) H, Me) have the
formula [{MeC6H3-3,5-(CCAu)2(µ-LL)}n] and are insoluble in organic solvents; they are
suggested to have a zigzag polymeric structure. In contrast, complexes with diphosphine
ligands (CH2)n(PPh2)2 (n ) 1-6) are soluble and are suggested to be the cyclic tetragold(I)
complexes of formula [{MeC6H3-3,5-(CCAu)2(µ-LL)}2]; the ring size varies from 24 to 34,
depending on n.
Ch a r t 1. P olym er s a n d Cyclic Com p ou n d s w ith
Bis(a lk yn ylgold (I)) Un its
In tr od u ction
There has been much interest in the use of p-
diethynylarenes as reagents in forming rigid-rod, orga-
nometallic polymers, which may contain square-planar
(Ni(II), Pd(II), Pt(II)) or octahedral (Rh(III), Fe(II), Ru-
(II), Os(II)) metal centers.1,2 These compounds have
interesting nonlinear optical properties, which might
lead to materials applications.1-3 A number of gold(I)
polymers, with linear gold(I) centers, have been pre-
pared, and their emission spectra suggest that there is
indeed some conjugation present, though the polymers
are insoluble.4,5 Neutral polymers require one
alkynylgold group and one other neutral ligand, and
examples of known oligomeric or polymeric structures
are illustrated in Chart 1. If the dialkyne or supporting
ligand is flexible, then rings and even catenated rings
rather than polymers may be formed (Chart 1).5-7
(1) (a) Hagihara, N.; Sonogashira, K.; Takahashi, S. Adv. Polym.
Sci. 1980, 41, 149. (b) Lewis, J .; Muhammad, S. K.; Ashok, K. K.;
J ohnson, B. F. G.; Marder, T. B.; Fyfe, H. B. J . Organomet. Chem.
1992, 425, 165. (c) Kotani, K. S.; Sonogashira, K. Appl. Organomet.
Chem. 1991, 5, 417. (d) Irwin, M. J .; J ia, G.; Vittal, J . J .; Puddephatt,
R. J . Organometallics 1996, 15, 5321.
(2) (a) Fyfe, H. B.; Mlekuz, M.; Zargarian, D.; Taylor, N. J .; Marder,
T. B. J . Chem. Soc., Chem. Commun., 1991, 188. (b) Atherton, Z.;
Faulkner, C. W.; Ingham, S. L.; Kakkar, A. K.; Khan, M. S.; Lewis, J .;
Long, N. J .; Raithby, P. R. J . Organomet. Chem. 1993, 462, 265. (c)
McDonagh, A. M.; Humphrey, M. G.; Samoc, M.; Luther-Davies, B.
Organometallics 1999, 18, 5195.
(3) Whittall, I. R,; McDonagh, A. M.; Humphrey, M. G. Adv.
Organomet. Chem. 1998, 42, 291.
(4) (a) J ia, G.; Payne, N. C.; Vittal, J . J .; Puddephatt, R. J .
Organometallics 1993, 12, 4771. (b) Irwin, M. J .; J ia, G.; Payne, N. C.;
Puddephatt, R. J . Organometallics 1996, 15, 51. (c) Irwin, M. J .; Vittal,
J . J .; Puddephatt, R. J . Organometallics 1997, 16, 3541.
It was of interest to explore the use of rigid, angular
diethynylarene ligands in forming gold(I) complexes,
polymers, or rings, and this paper reports the results
of this study using m-diethynylarenes in which the
(5) Puddephatt, R. J . Chem. Commun. 1998, 1055.
(6) (a) Irwin, M. J .; Rendina, L. M.; Vittal, J . J .; Puddephatt, R. J .
Chem. Commun. 1996, 1281. (b) McArdle, C. P.; Irwin, M. J .; J ennings,
M. C.; Puddephatt, R. J . Angew. Chem., Int. Ed. 1999, 38, 3376.
(7) (a) Manna, J .; Whiteford, J . A.; Stang, P. J . J . Am. Chem. Soc.
1996, 118, 8731. (b) Stang, P. J . Chem. Eur. J . 1998, 4, 19. (c) Stang,
P. J .; Olenyuk, B. Acc. Chem. Res. 1997, 30, 502.
10.1021/om0000461 CCC: $19.00 © 2000 American Chemical Society
Publication on Web 05/05/2000

Arenediethynyl Complexes of Gold(I)
Organometallics, Vol. 19, No. 11, 2000 2195
Sch em e 1
F igu r e 1. View of the structure of complex 3b, showing a
molecule and its two neighbors connected by Au‚‚‚Au bonds
(25% probability ellipsoids are shown).
F igu r e 2. View of the structure of complex 3d , showing
parallel ribbons formed by the two independent molecules
(25% probability ellipsoids are shown).
angle between the ethynyl groups is 120°, rather than
the more common 180° in rigid-rod ligands. There is
limited related work, including a binuclear cationic
complex containing octahedral iridium(III) centers
bridged by 1,2-diethynylbenzene.8 Also, 1,3,5-tri-
ethynylbenzene has been exploited in forming complexes
with platinum, iridium, and gold that may have novel
2-D polymeric structures.5,9-11
Complex 2 was converted to more soluble complexes
[MeC6H3-3,5-(CtCAuL)2] (3) by reaction with mono-
dentate isocyanide or phosphorus-donor ligands as
shown in Scheme 1. The pale yellow phosphite, phos-
phine, and isocyanide complexes were readily character-
ized by their spectroscopic properties. The IR spectra
for these compounds exhibit weak bands near 2120 cm-1
due to ν(CtC) and, for the isocyanide complexes, strong
bands at 2230-2260 cm-1 due to ν(NtC).14 The 1H
NMR spectra of 3 contain the expected resonances due
to both the alkynyl and neutral ligands, while the
phosphine and phosphite complexes each give a single
resonance in the 31P NMR spectra. Details are listed in
the Experimental Section. Only 3f was insufficiently
soluble to give a satisfactory NMR spectrum.
Two of the model complexes, 3b and 3d , have been
characterized crystallographically, and their structures
are shown in Figures 1 and 2, while selected bond
lengths and angles are presented in Tables 1 and 2.
Molecules of 3b (L ) P(OMe)3; Figure 1) have the
expected structure with roughly linear C-CtC-Au-P
units held at 120° to each other.4-6,11,15 The intramo-
lecular distances between the two gold and phosphorus
atoms (Au(1)-Au(2) ) 10.44 Å, P(1)-P(2) ) 14.27 Å)
are long, such that common bidentate ligands clearly
could not span the two gold(I) centers intramolecularly.
In the solid state, the molecules are associated to give
a ribbon structure, as shown in Figure 1, by formation
Resu lts a n d Discu ssion
Syn th esis of th e Bis(a lk yn e) a n d Mod el Gold (I)
Com p lexes. The ligand 3,5-diethynyltoluene was pre-
pared by reaction of the protected alkyne (trimethyl-
silyl)acetylene with 3,5-dibromotoluene, followed by
removal of the trimethylsilyl protecting groups with
potassium hydroxide (Scheme 1). A similar route has
been used to prepare 3,5-diethynylpyridine.12
3,5-Diethynyltoluene (1) was converted to the poly-
meric digold(I) diacetylide derivative [{MeC6H3-3,5-(Ct
CAu)2}n] (2) by reaction with [AuCl(SMe2)] in the
presence of sodium acetate (Scheme 1). Complex 2 was
isolated as a bright yellow, insoluble powder, and like
other gold(I) acetylides, it is presumed to have a
polymeric structure in which each acetylide is σ-bonded
(η1) to one gold atom and π-bonded (η2) to another.13
Some evidence for such a structure is obtained from the
IR spectrum of 2, which exhibits a weak band at 1985
cm-1; this band is 132 cm-1 lower than in the precursor
1 and indicates that the alkynyl groups are acting as
π-donors, but the insolubility of 2 did not allow char-
acterization by solution NMR.
(8) Stang, P. J .; Tykwinski, R. R. Organometallics 1994, 13, 3203.
(9) Khan, M. S.; Schwartz, D. J .; Pasha, N. A.; Kakkar, A. K.; Lin,
B.; Raithby, P. R.; Lewis, J . Z. Anorg. Allg. Chem. 1992, 616, 121.
(10) Leininger, S.; Stang, P. J .; Huang, S. P. Organometallics 1998,
17, 3981.
(11) (a) Irwin, M. J .; Manojlovic-Muir, Lj.; Muir, K. W.; Puddephatt,
R. J .; Yufit, D. S. Chem. Commun. 1997, 219. (b) Whittall, I. R.;
Humphrey, M. G.; Houbrechts, S.; Maes, J .; Persoons, A.; Schmid, S.;
Hockless, D. C. R. J . Organomet. Chem. 1997, 544, 277.
(12) Hagihara, N.; Sonogashira, K.; Takahashi, S.; Kuroyama, Y.
Synthesis 1980, 627.
(14) (a) J ia, G. C.; Puddephatt, R. J .; Vittal, J . J .; Payne, N. C.
Organometallics 1993, 263. (b) Kaharu, T.; Ishii, R.; Adachi, T.;
Yoshida, T. J . Mater. Chem. 1995, 687. (c) Xiao, H.; Cheung, K. K.;
Che, C. M. J . Chem. Soc., Dalton Trans. 1996, 3699.
(15) (a) Li, D.; Hong, X.; Che, C. M.; Lo, W.C.; Peng, S. M. J . Chem.
Soc., Dalton Trans. 1993, 2929. (b) Shieh, S. J .; Hong, X.; Peng, S. M.;
Che, C. M. J . Chem. Soc., Dalton Trans. 1994, 3067. (c) Yam, V. W.
W.; Choi, S. W. K.; Cheung, K. K. Organometallics 1996, 15, 1734. (d)
Naulty, R. H.; Cifuentes, M. P.; Humphrey, M. G.; Houbrechts, S.;
Boutton, C.; Persoons, A.; Heath, G. A.; Hockless, D. C. R.; Luther-
Davies, B.; Samoc, M. J . Chem. Soc., Dalton Trans. 1997, 4167. (e)
Vicente, J .; Chicote, M. T.; Abrisqueta, M. D. J . Chem. Soc., Dalton
Trans. 1995, 497.
(13) Mingos, D. M. P.; Yau, J .; Menzer, S.; Williams, D. J . Angew.
Chem., Int. Ed. Engl. 1995, 34, 1894.

2196 Organometallics, Vol. 19, No. 11, 2000
MacDonald et al.
Ta ble 1. Selected Bon d Dista n ces a n d An gles
for 3b
were insoluble in common organic solvents. The poly-
meric compounds have a ν(NtC) value of 2205 cm-1
,
which is similar to the ν(NtC) values of the model
compounds.14 In addition, XPS data shows that the
binding energy from these two compounds is 85.0 eV
Distances (Å)
Au(1)-P(1)
Au(1)-C(7)
O(1)-P(1)
O(2)-P(1)
O(3)-P(1)
C(7)-C(8)
C(8)-C(11)
C(13)-C(17)
2.261(4)
2.02(1)
1.55(1)
1.57(1)
1.56(1)
1.19(2)
1.46(2)
1.51(2)
Au(2)-P(2)
Au(2)-C(9)
O(4)-P(2)
2.249(4)
2.00(2)
1.56(2)
1.55(1)
1.60(2)
1.21(2)
1.45(2)
3.2196(9)
7
for Au (4f /2), which is in agreement with other two-
O(5)-P(2)
coordinate linear Au atoms in Au(I) complexes that
contain alkynyl and isocyanide ligands.4 The above
evidence demonstrates the presence of alkynyl(isocya-
nide)gold(I) units in 4a ,b, but the overall structures are
not defined by the spectroscopic data. Two possible
structures are the hexagonal cyclic structure [{MeC6H3-
3,5-(CtCAu)2(µ-L-L)}3] and the zigzag polymeric struc-
ture [{MeC6H3-3,5-(CtCAu)2(µ-L-L)}x]. The insolubility
of the compounds suggests, but does not prove, the
polymeric structure. We note that the planar hexagonal
structure would contain a large cavity (it would be a
102-membered ring) and so interpenetration might still
lead to polymer or oligomer formation.
O(6)-P(2)
C(9)-C(10)
C(10)-C(15)
Au(1)-Au(2)#1
Angles (deg)
C(8)-C(7)-Au(1)
P(1)-Au(1)-C(7)
Au(1)-P(1)-O(1)
Au(1)-P(1)-O(2)
Au(1)-P(1)-O(3)
C(8)-C(11)-C(12)
C(8)-C(11)-C(16)
176(1)
C(10)-C(9)-Au(2)
178(2)
175.7(5) P(2)-Au(2)-C(9)
117.9(5) Au(2)-P(2)-O(6)
107.9(4) Au(2)-P(2)-O(5)
118.9(4) Au(2)-P(2)-O(4)
178.1(5)
117.8(6)
111.7(5)
118.3(6)
120(1)
120(1)
C(10)-C(15)-C(14) 121(1)
C(10)-C(15)-C(16) 119(1)
C(14)-C(13)-C(17) 121(1)
C(12)-C(13)-C(17) 120(1)
Ta ble 2. Selected Bon d Len gth s a n d An gles for 3d
The reaction of the digold(I) diacetylide complex [{3,5-
MeC6H3(CtC-Au)2}n] (2) with the diphosphine ligands
shown in Scheme 3 yielded the complexes 5a -f. These
complexes were soluble in dichloromethane; therefore,
the two-step synthesis procedure used for the diisocya-
nide complexes was not necessary. Analogous diphos-
phine complexes of gold acetylides derived from 1,3,5-
triethynylbenzene or 1,4-diethynylbenzene are insoluble
and almost certainly have polymeric structures.4,11 The
major difference in solubility suggests a nonpolymeric
structure for complexes 5.
Distances (Å)
Au(1)-P(1)
TAu(1)-C(1)
C(1)-C(2)
C(2)-C(11)
Au(3)-P(3)
Au(3)-C(61)
C(61)-C(62)
C(62)-C(71)
Au(1)-Au(2)#1
2.275(9)
1.98(4)
1.24(4)
1.44(4)
2.298(8)
2.04(4)
1.18(4)
1.43(3)
3.124(2)
Au(2)-P(2)
Au(2)-C(3)
C(3)-C(4)
C(4)-C(15)
Au(4)-P(4)
Au(4)-C(63)
C(63)-C(64)
C(64)-C(75)
Au(3)-Au(4)#1
2.267(8)
2.00(3)
1.20(4)
1.43(3)
2.290(7)
2.09(3)
1.14(3)
1.45(3)
3.146(2)
Angles (deg)
C(2)-C(1)-Au(1)
P(1)-Au(1)-C(1)
Au(1)-P(1)-C(36)
Au(1)-P(1)-C(26)
Au(1)-P(1)-C(6)
174(3)
175.5(8)
114(1)
110(1)
116(2)
C(4)-C(3)-Au(2)
P(2)-Au(2)-C(3)
Au(2)-P(2)-C(46)
Au(2)-P(2)-C(56)
Au(2)-P(2)-C(7)
176(3)
174.1(9)
113.4(7)
111.2(9)
116(1)
The IR spectra show the expected weak peak due to
1
ν(CtC) at ca. 2120 cm-1. The H NMR spectra of each
complex 5 gave singlet resonances for the methyl and
aryl protons of the tolyl group as well as the expected
resonances for the diphosphine ligand. In addition, the
31P NMR spectrum of each complex exhibits one singlet,
indicating that there is only one species present and
that the phosphine groups are equivalent. The NMR
data are not consistent with polymer formation, and a
simple digold(I) complex is not possible because the ring
strain would be too great. The simplest structure
consistent with the spectroscopic data is the “dimer”
[{MeC6H3-3,5-(CtCAu)2(µ-L-L)}2], but larger rings and
even catenanes cannot be ruled out. Most of the com-
plexes failed to give parent ions in the FAB-MS, but 5a
gave a peak at m/z 1832 as expected for the dimer
formulation.16 The flexibility of the diphosphine ligands
allows formation of the dimers without significant ring
strain, as indicated by consideration of molecular models
or by molecular mechanics calculations, and, in the
absence of a structure determination, we tentatively
suggest that all complexes 5 have this structure.
C(62)-C(61)-Au(3) 176(3)
C(64)-C(63)-Au(4) 176(3)
C(63)-Au(4)-P(4) 171.4(7)
C(61)-Au(3)-P(3)
Au(3)-P(3)-C(96)
Au(3)-P(3)-C(86)
Au(3)-P(3)-C(66)
174.6(8)
110.04(9) Au(4)-P(4)-C(116) 113.3(8)
111.6(9)
115(1)
Au(4)-P(4)-C(106) 107.9(7)
Au(4)-P(4)-C(67) 104(1)
of intermolecular Au‚‚‚Au bonds (Au(1)-Au(2#) (e.g.,
Au(1A)-Au(2B) in Figure 1, which shows three equiva-
lent molecules designated A-C) ) 3.2196(9) Å).
The unit cell for 3d (L ) PMePh2, Figure 2) contains
two independent but similar molecules. The molecular
structure is similar to that of 3b. Each independent
molecule, containing Au(1), Au(2) and Au(3), Au(4),
respectively, forms its own independent but parallel
ribbon structure as shown in Figure 2. The gold‚‚‚gold
distances, which define the intermolecular aurophilic
attraction, are slightly shorter (Au(1)‚‚‚Au(2#) ) 3.124-
(2) Å; Au(3)‚‚‚Au(4#) ) 3.146(2) Å) than in 3b (3.2196-
(9) Å).
Syn th esis of Rin g a n d Zigza g P olym er ic Com -
p lexes. Linear, one-dimensional polymers [(Au-CtC-
Ar-CtC-Au-L-L)]x (Ar ) linear arene spacer group,
L-L ) p-diisocyanoarenes or diphosphines) have been
prepared by reaction of linear digold(I) diacetylide
complexes, [(Au-CtC-Ar-CtC-Au)]x, with the cor-
responding bidentate ligand L-L.4 However, a better
procedure when both precursor and product are in-
soluble is to convert the insoluble gold(I) acetylide to a
soluble complex by reaction with t-BuNC and then
replace the t-BuNC with the bidentate ligand. This
method was used to prepare the insoluble diisocy-
anobenzene derivatives 4a ,b shown in Scheme 2.
The products 4a ,b were formed as yellow solids that
Several conformations of the large rings (ring sizes:
5a , 24; 5b, 26; 5c, 28; 5d , 30; 5e, 32; 5f, 34) that result
from dimer formation are possible. A favored conforma-
tion, based on molecular mechanics calculations and
precedents, is the folded one shown in Scheme 3 for 5a .17
However, the 1H NMR spectrum of 5a gave only one
resonance for the CH2P2 protons, whereas the fixed,
folded conformation would give two. No major change
(16) Molecular weights of alkynylgold complexes by FAB-MS can
be misleading due to aggregation or fragmentation in the spectrom-
eter: Bruce, M. I.; Liddell, M. J . J . Organomet. Chem. 1992, 427, 263.
(17) Payne, N. C.; Ramachandran, R.; Puddephatt, R. J ., Can. J .
Chem. 1995, 73, 6.

Arenediethynyl Complexes of Gold(I)
Organometallics, Vol. 19, No. 11, 2000 2197
Sch em e 2
Ta ble 3. Em ission Sp ectr a a t Room Tem p er a tu r e
of Selected Com p lexes in Solu tion in
Sch em e 3
Dich lor om eth a n e a n d in th e Solid Sta tea
λ
max/nm
solid
λ
max/nm
solid
complex
soln
complex
soln
3a
3b
3c
3d
3e
3f
440
450
430
440
460
b
508, 540
575
507, 540
550
508, 560
560
4b
5a
5b
5c
5d
5e
b
440
440
440
450
450
580
510, 540
510, 540
540
508, 540
510, 540
4a
b
585
a
λ
b
In all cases
) 350 nm. Insufficiently soluble for solution
ex
study.
in which there is a plane of symmetry containing the
PCP atoms, sufficiently easily that the CH2 protons
1
appear equivalent. The H NMR data of all complexes
5 display similar effective symmetry. Hence, if trans-
annular Au‚‚‚Au attractions are present in the folded
structures, they must be weak.
Em ission Sp ectr a . A summary of the emission
spectra is given in Table 3, and typical spectra are
shown in Figure 3. All of the soluble complexes exhibited
room-temperature emission as dichloromethane solu-
tions, and all gave a single broad emission in the region
430-460 nm, similar to other alkynylgold(I) com-
plexes.4,14,15,18 The solid-state emission spectra of these
complexes all gave red-shifted bands compared to solu-
tion emission (Table 3), perhaps as a result of Au‚‚‚Au
interactions in the solid state.4,15,18 There were only
minor differences in the emission energies or appear-
ance of the emission spectra for the complexes with
monodentate phosphite, phosphine, or isocyanide ligands
and those containing bidentate phosphines (Table 3,
Figure 3). However, in some cases the solid-state
1
was observed in the low-temperature H NMR, and so
the rings must be able to reach a planar conformation,
(18) Yam, V. W. W.; Lo, K. K. W. Chem. Soc. Rev. 1999, 28, 323.

2198 Organometallics, Vol. 19, No. 11, 2000
MacDonald et al.
for 6 h. The solvent was removed under reduced pressure, and
the residue was then treated with aqueous KOH (20 mL, 1
M) and MeOH (100 mL) and the mixture refluxed overnight.
After removal of methanol, the product was extracted with
ether and then purified by chromatography on neutral alumina
using hexane as a eluent to afford a clear light yellow oil.
Yield: 0.50 g, 18%. NMR in CD2Cl2: δ(1H) 2.31 [s, 3H, CH3];
3.13 [s, 2H, CCH]; 7.31 [s, 2H, o-H]; 7.42 [s, 1H, p-H]; δ(13C)
133.84, 133.56, 133.38, 133.02 [aryl], 78.16 [CtCH], 77.89 [Ct
CH], 30.18 [CH3]. IR (Nujol, cm-1): ν(CC-H) 3300, ν(CtC)
2117(s), 2224.9. MS: m/z found 140.062 71, calcd for C11H8
140.062 60.
[{MeC6H3-3,5-(CtCAu )2}n ] (2). Caution! Shock-sensitive.
[AuCl(SMe2)] (0.4 g, 1.36 mmol) was suspended in THF (50
mL). A solution of 1 (0.095 g, 0.68 mmol) and NaO2CMe (0.11
g, 1.36 mmol) in THF (25 mL)/MeOH (15 mL) was added, and
the resulting mixture was stirred for 3 h, yielding a bright
yellow precipitate. The mixture was filtered and the yellow
solid washed with THF, MeOH, and pentane and dried in
vacuo. Yield: 0.32 g, 89%. The solid is insoluble in common
organic solvents. IR (Nujol, cm-1): ν(CtC) 1985 (w). Anal.
Calcd for C11H6Au2: C, 24.8; H, 1.1. Found C, 23.8; H, 1.1. The
analysis is poor since the insoluble material cannot be further
purifiedsfurther characterization is by formation of soluble
derivatives described below. A sample of compound 2 exploded
on scratching with a metal spatula.
F igu r e 3. Typical emission spectra: (top) complex 3c;
(bottom) complex 5c. In each case, spectrum a is for a
solution in dichloromethane and spectrum b is for the solid
state.
emission spectra showed resolved fine structure, at-
tributed to vibrational coupling, whereas in other cases
they did not (Figure 3). For the phosphine complexes,
the resolved bands were separated by ca. 1100 cm-1
,
probably indicating coupling to an aryl vibrational
mode. Following earlier discussion, the emission is
tentatively assigned as arising from a σ(AuC)-π*
excited state.4c The close similarity between spectra for
complexes containing monodentate phosphines (3c,d )
and bidentate phosphines (5a -e) indicates that the
methylene bridges in the diphosphine ligands prevent
conjugation effects, which might lead to a red shift.4c
In contrast, the diisocyanide complexes 4a ,b give solid-
state emissions that are red shifted compared to the
mono-isocyanide complexes 3e,f (Table 3), indicating
that there is extended conjugation in the diisocyanide
complexes.4c
[MeC6H3-3,5-{CtCAu P (OP h )3}2] (3a ). A mixture of 2 (0.22
g, 0.41 mmol) and P(OPh)3 (0.24 g, 0.83 mmol) in dichlo-
romethane (20 mL) was stirred for 30 min. The mixture was
filtered to remove suspended material, and then pentane (100
mL) was added to the filtrate to give the product as a white
solid, which was collected by filtration and washed with ether
and pentane. Yield: 0.30 g, 63%. NMR in CD2Cl2: δ(1H) 2.15
[s, 3H, CH3], 6.94 [s, 2H, o-H], 6.98 [s, 1H, p-H], 7.29-7.45
[m, 30H, Ph]; δ(31P) 138.18 [s]. IR (Nujol, cm-1): ν(CtC) 2115
(w). Anal. Calcd for C47H36O6P2Au2: C, 49.0; H, 3.1. Found:
C, 49.3; H, 3.1.
In summary, the angular 3,5-diethynyltoluene gives
complexes with monodentate ligands that form one-
dimensional ribbon structures through Au‚‚‚Au attrac-
tions in the solid state. With bidentate ligands, the rigid
linear diisocyanides appear to give zigzag polymeric
structures, whereas the more flexible diphosphines give
ring structures. The emission spectra indicate that
intermolecular Au‚‚‚Au bonding is present in all com-
plexes and that extended conjugation is present in the
diisocyanide complexes.
[MeC6H3-3,5-{CtCAu P (OMe)3}2] (3b). This was prepared
similarly from 2 (0.20 g, 0.38 mmol) and P(OMe)3 (0.081 g,
0.752 mmol). Yield: 0.20 g, 68%. NMR in CD2Cl2: δ(1H) 2.22
[s, 3H,CH3], 7.05 [s, 2H, o-H], 7.15 [s, 1H, p-H], 3.76 [d, 18H,
2J (PH) ) 16 Hz, CH3]; δ(31P) 150.34 [s]. IR (Nujol, cm-1):
ν(CtC) 2120 (w). Anal. Calcd for C17H24O2P2Au2: C, 26.2; H,
3.1. Found: C, 26.0; H, 3.1.
[MeC6H3-3,5-(CtCAu P P h 3)2]‚0.5CH2Cl2 (3c). This was
prepared similarly from 2 (0.20 g, 0.38 mmol) and PPh3 (0.20
g, 0.76 mmol). Yield: 0.26 g, 65%. NMR in CD2Cl2: δ(1H) 2.23
[s, 3H, CH3], 7.09 [s, 2H, o-H], 7.21 [s, 1H, p-H], 7.5 [m, 30H,
Ph]; δ(31P) 42.80 [s]. IR (Nujol, cm-1): ν(CtC) 2120 (w), 2212
(w). Anal. Calcd for C47H36P2Au2‚0.5CH2Cl2: C, 51.9; H, 3.4.
Found: C, 51.3; H, 3.4. The presence of dichloromethane was
Exp er im en ta l Section
NMR spectra were collected by using a Varian Gemini 300
MHz spectrometer, and chemical shifts are referenced to TMS
or phosphoric acid. IR spectra were recorded as Nujol mulls
on KBr plates using a Perkin-Elmer 2000 FTIR. Mass spectra
were recorded by using a Finnigan-MAT 8200 spectrometer.
[AuCl(SMe2)] and diisocyanoarenes were prepared by litera-
ture methods.19-21
MeC6H3-3,5-(CtCH)2 (1). To a mixture of (trimethylsilyl)-
acetylene (5.89 g, 0.06 mmol) and m-dibromotoluene (5.0 g,
0.02 mmol) in piperidine (100 mL) were added Pd(PPh3)2Cl2
(0.5 g) and CuI (0.2 g). The reaction mixture was stirred for 6
h at 90 °C under an atmosphere of N2. Additional catalyst (as
above) and (trimethylsilyl)acetylene (0.02 mmol) were added
at this point, and the reaction mixture was heated and stirred
1
confirmed by H NMR.
[MeC6H3-3,5-(CtCAu P MeP h 2)2] (3d ). This was prepared
similarly from 2 (0.20 g, 0.38 mmol) and PMePh2 (0.15 g, 0.76
mmol). Yield: 0.24 g, 67%. NMR in CD2Cl2: δ(1H) 2.22 [s, 3H,
2
CH3], 7.06 [s, 2H, o-H], 7.18 [s, 1H, p-H], 2.05 [d, 6H, J (PH)
) 9.3 Hz, PMe], 7.4-7.7 [m, 20H, Ph]; δ(31P) 25.17 [s]. IR
(Nujol, cm-1): ν(CtC) 2120 (w), 2212 (w). Anal. Calcd for
C
37H32P2Au2: C, 47.7; H, 3.5. Found: C, 47.9; H, 3.4.
[MeC6H3-3,5-(CtCAu CN-t-Bu )2] (3e). This was prepared
similarly from 2 (0.10 g, 0.19 mmol) and t-BuNC (31.42 mg,
0.38 mmol). Yield: 0.062 g, 47%. NMR in CD2Cl2: δ(1H) 2.21
[s, 3H, CH3], 7.02 [s, 2H, o-H], 7.12 [s, 1H, o-H], 1.55 [s, 18H,
Bu]. IR (Nujol, cm-1): ν(CtC) 2120 (w), ν(CtN) 2229 (s).
7
XPS: BE(Au 4f /2) ) 85.0 eV. Anal. Calcd for C21H24N2Au2:
C, 36.1; H, 3.5; N, 4.0. Found: C, 36.0; H, 3.6; N, 3.9.
(19) Tamaki, A.; Kochi, J . K. J . Organomet. Chem. 1974, 64, 411.
(20) Gokel, G. W.; Widera, R. P.; Weber, W. P.; South-Bachiller, F.
A.; Masamune, S.; Talkowski, C. J .; Sheppard, W. A. Org. Synth. 1975,
55, 96.
(21) Hoffman, P. T.; Gokel, G.; Marquerding, D.; Ugi, I. In Isonitrile
Chemistry; Ugi. I., Ed.; Academic Press: New York, 1971.
[MeC6H3-3,5-(CtCAu CNMe)2] (3f). This was prepared
similarly from 2 (0.10 g, 0.19 mmol) and MeNC (15.52 mg,
0.38 mmol). Yield: 0.080 g, 69%. IR (Nujol, cm-1): ν(CtN)
2259 (s), ν(CtC) 2120(w). XPS: BE(Au 4f 7/2) ) 85.0 eV. Anal.

Arenediethynyl Complexes of Gold(I)
Organometallics, Vol. 19, No. 11, 2000 2199
Ta ble 4. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
Calcd for C15H12N2Au2: C, 29.3; H, 2.0; N, 4.6. Found: C, 29.0;
H, 2.0; N, 4.6.
3b
3d
[{MeC6H3-3,5-(CtCAu )2(µ-1,4-C6H4(NC)2}n ] (4a ). To a
solution of 3e (0.086 g, 0.12 mmol) in THF (10 mL) was added
1,4-C6H4(NC)2 (20.8 mg, 0.16 mmol) in THF (10 mL). The
mixture was stirred for 12 h to yield the product as a yellow
precipitate, which was collected by filtration, washed with
THF, MeOH, and ether, and dried in vacuo. Yield: 0.068 g,
63%. IR (Nujol, cm-1): ν(NtC) 2205 (s), ν(CtC) 2127 (w). Anal.
Calcd for C19H10N2Au2: C, 34.6; H, 1.5; N, 4.2. Found: C, 34.4;
formula, fw
C
17H24Au2O6P2,
780.23
C37H32Au2P2,
932.50
298(2)
0.710 73
monoclinic, P21/c
T/K
298(2)
0.710 73
triclinic, P1h
wavelength/Å
system, space group
cell dimens
a, Å
b, Å
c, Å
7.3441(3)
36.0828(4)
10.5122(1)
17.9674(3)
10.4689(5)
15.7477(7)
93.344(2)
100.786(1)
103.835(2)
1148.10(9), 2
2.257
12.930, 724
semiempirical
0.0508, 0.1244
7
H, 1.3; N, 4.2. XPS: BE(Au 4f /2) ) 85.0 eV.
R, deg
[{MeC6H3-3,5-(CtCAu )2(µ-1,4-C6Me4(NC)2}n ] (4b). This
was prepared similarly from 3e (0.08 g, 0.12 mmol) and 1,4-
C6Me4(NC)2 (27.8 mg, 0.15 mmol). Yield: 0.076 g, 70%. IR
(Nujol, cm-1): ν(NtC) 2205 (s), ν(CtC) 2127 (w). Anal. Calcd
for C23H18N2Au2: C, 38.6; H, 2.5; N, 3.9. Found: C, 38.1; H,
â, deg
92.691(1)
γ, deg
V/Å3, Z
6807.7(2), 8
1.820
8.727, 3536
semiempirical
0.0968, 0.1906
d
calcd/Mg m-3
abs coeff/mm-1, F(000)
abs cor
7
2.2; N, 3.6. XPS: BE(Au 4f /2) ) 85.0 eV.
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P CH2P P h 2)}2] (5a ). A mix-
ture of 2 (0.10 g, 0.19 mmol) and Ph2PCH2PPh2 (72.6 mg, 0.19
mmol) in dichloromethane (20 mL) was stirred for 30 min. The
mixture was filtered, and pentane (100 mL) was added to the
filtrate to precipitate the product as a white solid, which was
collected by filtration and washed with ether and pentane.
Yield: 0.082 g, 69%. NMR in CD2Cl2: δ(1H) 2.12 [s, 3H, CH3],
6.99 [s, 2H, o-H], 7.14 [s, 1H, p-H], 2.12 [m, 2H, CH2], 7.4-7.7
[m, 20H, Ph]; δ(31P) 33.61 [s]. IR (Nujol, cm-1): ν(CtC) 2117
(w), 2225 (w). Anal. Calcd for C36H28P2Au2: C, 47.2; H, 3.1.
Found: C, 47.4; H, 3.0.
R1, wR2 (I > 2σ(I))
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P (CH2)6P P h 2)}2] (5f). This
was prepared similarly from 2 (0.05 g, 0.094 mmol) and
Ph2P(CH2)6PPh2 (42.7 mg, 0.094 mmol). Yield: 0.075 g, 81%.
NMR in CD2Cl2: δ(1H) 2.20 [s, 3H, CH3], 7.05 [s, 2H, o-H],
7.19[s, 1H, p-H], 1.41 [m, 4H, CH2, 1.61 [m, 4H, CH2], 2.38
[m, 4H, CH2], 7.4-7.7 [m, 20H, Ph]; δ(31P) 36.54 [s]. IR (Nujol,
cm-1): ν(CtC) 2120 (w). Anal. Calcd for C41H38P2Au2: C, 49.9;
H, 3.9. Found: C, 50.4; H, 3.8.
Str u ctu r a l Deter m in a tion of 3b a n d 3d . Suitable crys-
tals were mounted on thin, glass fibers using paraffin oil. Data
were collected using a Bruker AX SMART 1K CCD diffracto-
meter using 0.3° ω-scans at 0, 90, and 180° in φ. Crystal data
and structure refinement details are given in Table 4. Unit-
cell parameters were determined from 60 data frames collected
at different sections of the Ewald sphere. Semiempirical
absorption corrections based on ψ scans were applied. Sys-
tematic absences in the diffraction data and unit-cell param-
eters were consistent with P1 and P1h for 3b and uniquely with
P21/c for 3d . Solution in the centric space group for 3b yielded
computationally stable and chemically reasonable results of
refinement. The structures were solved by direct methods,
completed with difference Fourier syntheses, and refined with
full-matrix least-squares procedures based on F2. For complex
3d , the aromatic groups were treated as rigid hexagons. All
non-hydrogen atoms were refined with anisotropic displace-
ment parameters. All hydrogen atoms were treated as ideal-
ized contributions. All scattering factors and anomalous
dispersion factors are contained in the SHELXTL 5.10 program
library (G. M. Sheldrick, Bruker AXS, Madison, WI, 1997).
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P (CH2)2P P h 2)}2] (5b). This
was prepared similarly from 2 (0.20 g, 0.38 mmol) and
Ph2P(CH2)2PPh2 (0.15 g, 0.38 mmol). Yield: 0.20 g, 57%. NMR
in CD2Cl2: δ(1H) 2.23 [s, 3H, CH3], 7.08 [s, 2H, o-H], 7.26 [s,
1H, p-H], 2.72 [m, 4H, CH2], 7.5-7.7 [m, 20H, Ph]; δ(31P) 35.14
[s]. IR (Nujol, cm-1): ν(CtC) 2117 (w), 2225 (w). Anal. Calcd
for C37H30P2Au2: C, 47.8; H, 3.2. Found: C, 47.8; H, 3.1.
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P (CH2)3P P h 2)}2] (5c). This
was prepared similarly from 2 (0.10 g, 0.19 mmol) and
Ph2P(CH2)3PPh2 (78.0 mg, 0.19 mmol). Yield: 0.13 g, 73%.
NMR in CD2Cl2: δ(1H) 2.24 [s, 3H, CH3], 7.07 [s, 2H, o-H],
7.25 [s, 1H, p-H], 1.88 [m, 2H, CH2], 2.77 [m, 4H, CH2], 7.4-
7.8 [m, 20H, Ph]; δ(31P) 35.27 [s]. IR (Nujol, cm-1): ν(CtC)
2117 (w), 2225 (w). Anal. Calcd for C38H32P2Au2: C, 48.3; H,
3.4. Found: C, 48.0; H, 3.2.
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P (CH2)4P P h 2)}2] (5d). This
was prepared similarly from 2 (0.05 g, 0.094 mmol) and
Ph2P(CH2)4PPh2 (40.0 mg, 0.094 mmol). Yield: 0.076 g, 84%.
NMR in CD2Cl2: δ(1H) 2.22 [s, 3H, CH3], 7.06 [s, 2H, o-H],
7.25 [s, 1H, p-H], 1.67 [m, 4H, CH2, 2.46 [m, 4H, CH2], 7.4-
7.6 [m, 20H, Ph]; δ(31P) ) 35.39 [s]. IR (Nujol, cm-1): ν(CtC)
2120 (w). Anal. Calcd for C39H34P2Au2: C, 48.9; H, 3.6.
Found: C, 49.2; H, 3.5.
Ack n ow led gm en t. We thank the NSERC of Canada
for financial support.
[{MeC6H3-3,5-(CtCAu )2(µ-P h 2P (CH2)5P P h 2)}2] (5e). This
was prepared similarly from 2 (0.05 g, 0.094 mmol) and
Ph2P(CH2)5PPh2 (41.4 mg, 0.094 mmol). Yield: 0.078 g, 85%.
NMR in CD2Cl2: δ(1H) 2.20 [s, 3H, CH3], 7.04 [s, 2H, o-H],
7.18 [s, 1H, p-H], 1.55 [m, 4H, CH2], 1.73 [m, 2H, CH2], 2.40
[m, 4H, CH2], 7.4-7.7 [m, 20H, Ph]; δ(31P) 36.15 [s]. IR (Nujol,
cm-1): ν(CtC) 2120 (w). Anal. Calcd for C40H36P2Au2: C, 49.4;
H, 3.7. Found: C, 50.0; H, 3.7.
Su p p or tin g In for m a tion Ava ila ble: Tables of X-ray data
for complexes 3b and 3d . This material is available free of
charge via the Internet at http://pubs.acs.org.
OM0000461