Rigid-rod polymers and model compounds with gold(I) centers bridged by diisocyanides and diacetylides

Article abstract of DOI:10.1021/om950659r

Binuclear alkynyl(isocyanide)gold(I) complexes have been prepared by reaction of oligomeric precursors [(AuC≡CRC≡CAu)_n (R = C₆H₄, C₆H₄C₆H₄, 2,5-C₆H₂Me₂, CH₂OC₆H₄C(Me)₂-C₆H ₄OCH₂) with 2,6-dimethylphenyl isocyanide (XyN≡C) to give [XyN≡CAuC≡CR-C≡CAuC≡NXy] or by reaction of [(R′C≡CAu)_n] with a diisocyanide CNRNC to give [R′C≡CAuCNRCAuCNC≡CR′] (R = C₆H₄, 2-MeC₆H₃, C₆Me₄, 2,5-Me₂C₆H₂-2,5-Me₂C ₆H₂, 2,5-C₆H₂(t-Bu)₂; R′ = t-Bu or Ph). The products were characterized spectroscopically and, for R = 2,5-C₆H₂(t-Bu)₂; and R′ = Ph, by an X-ray structure determination. The molecule has a rodlike structure, and there is a bowing of the isocyanide ligand, angle C-N≡C = 168(2)°, which allows the molecules to pack in zigzag chains with short intermolecular Au··Au contacts of 3.174(1) A? to give a loosely held polymeric structure. Analogous σ-bonded, conjugated rigid-rod polymeric complexes are prepared by reactions of the linear digold complexes [(AuC≡CRC≡CAu)_n] (R = C₆H₄, C₆H₄C₆H₄, C₆H₂Me₂ and CH₂OC₆H₄C(Me)₂C₆H ₄OCH₂) with appropriate diisocyanoarenes C≡NR′N≡C (R′ = C₆H₄, C₆H₃Me, C₆Me₄, C₆H₂Me₂C₆H₂Me ₂, C₆H₂-t-Bu₂) to give [(AuC≡CRC≡CAuC≡NR′N≡C)_x]. These polymers are insoluble and are characterized by elemental analysis, IR and XPS methods; the IR, and XPS data indicate that the polymers contain the same functional groups as the binuclear model complexes. It is argued that the low solubility results in part from crosslinking due to interchain Au··Au contacts of the kind established crystallographically in the model binuclear complex.

Full text of DOI:10.1021/om950659r

Organometallics 1996, 15, 51-57
51
Rigid -Rod P olym er s a n d Mod el Com p ou n d s w ith Gold (I)
Cen ter s Br id ged by Diisocya n id es a n d Dia cetylid es
Michael J . Irwin, Guochen J ia, Nicholas C. Payne, and Richard J . Puddephatt*
Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7
Received August 23, 1995X
Binuclear alkynyl(isocyanide)gold(I) complexes have been prepared by reaction of oligo-
meric precursors [(AuCtCRCtCAu)n] (R ) C6H4, C6H4C6H4, 2,5-C6H2Me2, CH2OC6H4C(Me)2-
C6H4OCH2) with 2,6-dimethylphenyl isocyanide (XyNtC) to give [XyNtCAuCtCR-
CtCAuCtNXy] or by reaction of [(R′CtCAu)n] with a diisocyanide CNRNC to give
[R′CtCAuCNRCAuCNCtCR′] (R ) C6H4, 2-MeC6H3, C6Me4, 2,5-Me2C6H2-2,5-Me2C6H2, 2,5-
C6H2(t-Bu)2; R′ ) t-Bu or Ph). The products were characterized spectroscopically and, for R
) 2,5-C6H2(t-Bu)2; and R′ ) Ph, by an X-ray structure determination. The molecule has a
rodlike structure, and there is a bowing of the isocyanide ligand, angle CsNtC ) 168(2)°,
which allows the molecules to pack in zigzag chains with short intermolecular Au‚‚Au contacts
of 3.174(1) Å to give a loosely held polymeric structure. Analogous σ-bonded, conjugated
rigid-rod polymeric complexes are prepared by reactions of the linear digold complexes
[(AuCtCRCtCAu)n] (R ) C6H4, C6H4C6H4, C6H2Me2 and CH2OC6H4C(Me)2C6H4OCH2) with
appropriate diisocyanoarenes CtNR′NtC (R′ ) C6H4, C6H3Me, C6Me4, C6H2Me2C6H2Me2,
C6H2-t-Bu2) to give [(AuCtCRCtCAuCtNR′NtC)x]. These polymers are insoluble and are
characterized by elemental analysis, IR and XPS methods; the IR, and XPS data indicate
that the polymers contain the same functional groups as the binuclear model complexes. It
is argued that the low solubility results in part from crosslinking due to interchain Au‚‚Au
contacts of the kind established crystallographically in the model binuclear complex.
In tr od u ction
bipyridyl derivatives) have also been reported to show
electrical conducting properties.11 In this regard, it
would be interesting to synthesize and characterize
novel rigid-rod metal-containing polymers in which the
metal centers are connected consecutively with conju-
gated diisocyanides and conjugated diacetylides. The
properties of the polymeric species could be easily
There has been great interest in the synthesis and
properties of linear chain metal-containing polymers
with extended backbone conjugation through dπ-pπ or
σ*-pπ overlap leading toward potential applications as
advanced materials.1 In particular, polymeric species
of the type [MLn(-CtCRCtC-)]n (MLn ) d6 to d8 metal
fragments; R ) aromatic rings, disilanes, or disiloxanes)
are attracting increasing attention because of their
electrical conducting, nonlinear optical, and liquid
crystalline properties.2-7 One- and two-dimensional
polymers with diisocyanoarenes linking metal centers
are also known.8,9 It is interesting to note that polymers
of the type [PcM(CNRNC)]x (Pc ) phthalocyanine; M )
Fe, Ru) display semiconducting properties.1,8 Novel
rigid-rod Au-containing polymeric complexes where Au
centers are bridged by isocyanoarylacetylides have
recently been synthesized.10 Cationic palladium com-
plexes [Pd(PBu 3)2CtCRCtCPd(PBu3)2(L-L)]n (L-L )
(4) (a) Davies, S. J .; J ohnson, B. F. G.; Khan, M. S.; Lewis, J . J .
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Wacherle, L.; Goldman, A.; Efraty, A. J . Chem. Soc., Dalton Trans.
1988, 469. (d) Keppler, U.; Hanack, M. Chem. Ber. 1986, 119, 3363.
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N. C.; Puddephatt, R. J . Inorg. Chem. 1994, 33, 2355. (b) Rashidi, M.;
Kristof, E.; Vittal, J . J .; Puddephatt, R. J . Inorg. Chem. 1994, 33, 1497.
(10) (a) J ia, G.; Payne, N. C.; Vittal, J . J .; Puddephatt, R. J .
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J . J .; Payne, N. C. Organometallics 1993, 12, 263.
X Abstract published in Advance ACS Abstracts, December 1, 1995.
(1) See for example: (a) Hirsch, A.; Hanack, M. In Conjugated
Polymeric Materials: Opportunities in Electronics, Optoelectronics and
Molecular Electronics; Bredas, J . L., Chance, R. R., Eds.; Kluwer: New
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U.; Koch, J . In Handbook of Conducting Polymers; Skotheim, T. A.,
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0276-7333/96/2315-0051$12.00/0 © 1996 American Chemical Society

52 Organometallics, Vol. 15, No. 1, 1996
Irwin et al.
are reported relative to tetramethylsilane. IR spectra were
recorded as Nujol mulls by using either one of a Bruker IFS32
spectrometer or a Perkin-Elmer FTIR. DSC analyses were
carried out on a General V2.2A Dupont 9900 DSC thermal
analyzer. Elemental analyses were performed by Guelph
Chemical Laboratories Ltd., Guelph, Ontario.
altered by changing the properties of the individual
ligands involved.
This report describes the synthesis and characteriza-
tion of gold-containing polymers of the formula (Au-
CtNRNtCAuCtCR′CtC-)n. Aryl diisocyanides and
aryldiacetylides are chosen since they often form strong
metal-ligand bonds, they have been used separately for
the synthesis of interesting polymers, and their geom-
etries are ideal for linear polymers. Gold(I) was chosen
as the metal center since it tends to form simple two-
coordinated linear complexes12 and because gold alkynyl
complexes of formula [Au(CtCR)(L)] (L ) phosphine,
arsine, stibine, isocyanide, and amine) are among the
most stable organogold complexes and are known to
have linear geometry.13-16 Hence rigid-rod Au-contain-
ing polymers of the type (AuCtNRNtCAuCtC-R′-
CtC-)n were considered a logical target. They are
related to the polymers (AuCtNRCtC-)n reported
previously.10
1,4-(NHCHO)2-2,5-(t-Bu )2-C6H2. 1,4-Diamino-2,5-di-tert-
butylbenzene (10 g, 0.45 mmol) was added to 96% formic acid
(ca. 100 mL). The mixture was warmed to 85 °C and allowed
to stir for 10 h. The volume of the mixture was reduced under
vacuum to leave an off white solid which was collected by
filtration and subsequently washed with ether, pentane, and
hexanes and dried. Yield: 10.9 g, 88%. NMR in acetone-d6:
δ(1H) ) 1.38 [s, 18H, t-Bu]; 7 [s, 2H, Ph]; 8.42 [s, 2H, CHO].
MS: m/ z ) 276 amu; calcd for C16H24N2O2, m/ z ) 276.
1,4-(NC)2-2,5-(t-Bu )2-C6H2. Phosgene (4 g, 41 mmol) (Ca u -
tion : a highly toxic gas) was led into a suspension of 2,5-di-
tert-butyl-1,4-diformylbenzene (5 g,18 mmol) in CH2Cl2 (150
mL) and diethylamine (11 mL). The mixture was stirred for
0.5 h until cessation of boiling resulting from the very
exothermic reaction. A steady stream of ammonia was bubbled
quickly into the mixture for ca. 5 min, after which time the
resulting suspension was filtered. The filtrate was concen-
trated under vacuum, and the resulting light brown precipitate
was dried. The product was purified by sublimation to yield
a white crystalline solid. Yield: 3.69 g, 85%. NMR in CDCl3:
δ(1H) ) 1.47 [s, 18H, t-Bu]; 7.38 [s, 2H, Ph]. IR (Nujol): υ-
(CtN) ) 2102 cm-1. MS: m/ z ) 240 amu; calcd for C16H20N2,
m/ z ) 240.
Exp er im en ta l Section
All chemicals were used as purchased from Aldrich Chemi-
cal Co. unless otherwise stated. Gold metal was purchased
from J ohnson Matthey Co. [AuCl(SMe2)],17 [AuCtCPh], and
[AuCtC-t-Bu)]18 were prepared by modified literature methods
[Ca u tion : some gold acetylides are potentially explosive; they
should be prepared in small quantities and not subjected to
shock!]. p-Diisocyanoarenes19 (with the exception of 2,5-di-
tert-butyl-1,4-diisocyanobenzene) were synthesized from p-
diaminoarenes via the phase-transfer Hofmann carbylamine
reaction20 and were purified by column (neutral alumina)
chromatography or sublimation. p-Diethynylarenes21 were
prepared from p-dibromoarenes and 2-methylbut-3-yn-2-ol
using the procedure of Ames et al.22 and were purified by
sublimation. The catalyst CuI was prepared from the reaction
of CuSO4 and KI. [PdCl2(PPh3)2]23a was prepared from the
reaction of PPh3 with [PdCl2(PhCN)2].23b
[Au 2(CtCC6H4C6H4CtC)]n . AuCl(SMe2)(0.90g,3.06mmol)
was dissolved in the mixed solvents THF (200 mL)/MeOH (100
mL). To the solution was then added a solution of 4,4′-
HCtCC6H4C6H4CtCH (0.300 g, 1.48 mmol) and NaO2CMe
(0.60 g, 7.3 mmol) in THF (25 mL)/MeOH (25 mL). The
resulting mixture was then stirred overnight (ca. 10 h) to
produce a bright yellow precipitate. The solid was then
collected by filtration, washed with THF, MeOH, water, MeOH
and ether, and dried. Yield: 0.85 g, 97%. The solid is
insoluble in common organic solvents. IR (Nujol): υ(CtC) )
2000 (w) cm-1
. Anal. Calcd for C16H8Au2: C, 32.3; H, 1.4.
NMR spectra were recorded by using a Varian XL 200 or
Gemini 200 spectrometer. 1H NMR chemical shifts were
measured relative to partially deuterated solvent peaks but
Found: C, 32.7; H, 1.7.
[Au 2(CtCC6H2Me2CtC)]x. A solution of 4,4′-(HCtC) 2-2,5-
Me2C6H2 (0.150 g, 0.973 mmol) and NaO2CMe (0.40 g, 4.9
mmol) in THF (5 mL)/MeOH (20 mL) was added to a solution
of AuCl(SMe2) (0.600 g, 2.04 mmol) in the mixed solvents THF
(80 mL)/MeOH (20 mL). The resulting mixture was then
stirred overnight (ca. 10 h) to produce a bright yellow
precipitate. The solid was then collected by filtration, washed
with THF, MeOH, water, MeOH, and ether, and dried.
Yield: 0.85 g, 97%. The solid is insoluble in common organic
solvents. IR (Nujol): υ(CtC) ) 2018 (w), 1972 (w) cm-1. Anal.
Calcd for C12H8Au2: C, 26.4; H, 1.5. Found: C, 26.0; H, 1.4.
[(2,6-Me2C6H3NCAu )2(µ-CtCC6H4C6H4CtC)]. A mixture
of Au2(CtCC6H4C6H4CtC) (0.10 g, 0.17 mmol) and 2,6-
Me2C6H3NC (50 mg, 0.38 mmol) in dichloromethane (100 mL)
was stirred for 1 h to give a slightly cloudy solution. The
solvent was removed completely, and the residue was washed
with ether to give a pale yellow solid. The solid was collected
by filtration, washed with ether, and dried. Yield: 0.13 g, 89%.
NMR (CDCl3) δ(1H) ) 2.46 (s, 12H, Me), 7.15-7.57 (m, 14H,
(12) (a) Assefa, Z.; McBurnett, B. G.; Staples, R. J .; Fackler, J . P.;
Assmann, B.; Angermaier, K.; Schmidbaur, H. Inorg. Chem. 1995, 34,
75. (b) Fackler, J . P.; Staples, R. J .; Assefa, Z. J . Chem. Soc., Chem.
Commun. 1994, 431. (c) Stu¨tzer, A.; Bissinger, P.; Schmidbaur, H. Z.
Naturforsch., Sect.
B 1992, 47, 1261. (d) Puddephatt, R. J . In
Comprehensive Organometallic Chemistry; Wilkinson, G., Stone, F. G.
A., Abel, E. W., Eds.; Pergamon: London, 1982; Vol. 2, 756. (e)
Anderson, G. K. Adv. Organomet. Chem. 1982, 20, 39. (f) Puddephatt,
R. J . In The Chemistry of Gold; Elsevier: Amsterdam 1978. (g)
Pathaneni, S. S.; Desiraju, G. R. J . Chem. Soc., Dalton Trans. 1993,
319.
(13) Corfield, P. W. R.; Shearer, H. M. M. Acta Crystallogr. 1967,
23, 156.
(14) (a) Payne, N. C.; Ramachandran, R.; Puddephatt, R. J . Can. J .
Chem. 1995, 73, 6. (b) Che, C.-M.; Yip, H.-K.; Lo, W.-C.; Peng, S.-M.
Polyhedron 1994, 13, 887.
(15) Carriedo, G. A.; Riera, V.; Solans, X.; Solans, J . Acta Crystallogr.
1988, C44, 978.
(16) (a) Bruce, M. I.; Grundy, K. R.; Liddell, M. J .; Snow, M. R.;
Tiekink, E. R. T. J . Organomet. Chem. 1988, 344, C88. (b) Bruce, M.
I.; Horn, E.; Matisons, J . G.; Snow, M. R. Aust. J . Chem. 1984, 37,
1163. (c) J ohnson, B. F. G.; Kakkar, A. K.; Khan, M. S.; Lewis, J . J .
Organomet. Chem. 1991, 409, C12.
(17) Tamaki, A.; Kochi, J . K. J . Organomet Chem. 1974, 64, 411.
(18) Coates, G. E.; Parkin, C. J . Chem. Soc. 1962, 3220.
(19) Hoffman, P. T.; Gokel, G.; Marquerding, D.; Ugi, I. In Isonitrile
Chemistry; Ugi, I., Ed.; Academic Press: New York. 1971.
(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.
Ph). IR (Nujol): υ(NtC) ) 2211 (s) cm-1
34H26Au2N2: C, 47.7; H, 3.1. Found: C, 48.1; H, 3.4.
[(2,6-Me2C6H3NCAu )2(µ-CtCC6H2Me2CtC)]. A mixture
. Anal. Calcd for
C
of Au2(CtCC6H2Me2CtC) (0.10 g, 0.18 mmol) and 2,6-Me2C6H3-
NC (50 mg, 0.38 mmol) in dichloromethane (30 mL) was stirred
for 1 h. The solvent was then removed completely, and the
residue was washed with hexane to give a light yellow solid.
The solid was collected by filtration, washed with ether, and
dried. Yield: 0.13 g, 89%. NMR (CDCl3): δ(1H) ) 2.41 (s,
6H, Me), 2.44 (s, 12H, Me), 7.14-7.33 (m, 8H, Ph). IR
(Nujol): 2220 (s), 2165 (sh), 2039 (br, w) cm-1. Anal. Calcd
for C30H26Au2N2: 44.5; H, 3.2. Found: C, 44.3; H, 3.0.
(21) Takahashi, S.; Kuroyama, Y.; Sonogashira, K.; Hagihara, N.
Synthesis 1980, 627.
(22) Ames, D. E.; Bull, D.; Takundwa, C. Synthesis 1981, 364.
(23) (a) Chatt, J .; Mann, F. G. J . Chem. Soc. 1939, 1623. (b) Doyle,
J . R.; Slade, P. E.; J onassen, H. B. Inorg. Synth. 1960, 6, 216.

Model Compounds with Gold(I) Centers
Organometallics, Vol. 15, No. 1, 1996 53
[(t-Bu CtCAu )2(µ-CNC6H4NC)]. A mixture of t-BuCtCAu
(0.10 g, 0.36 mmol) and CNC6H4NC (23 mg, 0.18 mmol) in
dichloromethane (10 mL) was stirred for 30 min. The solvent
was then removed completely, and the residue was washed
with hexane to give a light yellow solid. The solid was collected
by filtration, washed with hexane, and dried. Yield: 110 mg,
89%. NMR (CDCl3): δ(1H) ) 1.27 (s, 18H, Bu), 7.67 (s, 4H,
Ph). IR (Nujol): 2211 (s), 2122 (sh), 2040 (br, w) cm-1. Anal.
Calcd for C20H22Au2N2: C, 35.1; H, 3.2. Found: C, 35.4; H,
3.0.
[(t-Bu CtCAu )2(µ-CNC6H 3MeNC)]. A mixture of t-Bu-
CtCAu (0.10 g, 0.36 mmol) and CNC6H3MeNC (26 mg, 0.18
mmol) in dichloromethane (10 mL) was stirred for 30 min. The
solvent was then removed completely, and the residue was
washed with hexane to give a light yellow solid. The solid was
collected by filtration, washed with hexane, and dried. Yield:
113 mg, 90%. NMR (CDCl3): δ(1H) ) 1.27 (s, 18H, Bu), 2.48
(s, 3H, Me), 7.45-7.62 (m, 3H, Ph). IR (Nujol): 2207 (s), 2111
(sh), 2034 (br, w) cm-1. Anal. Calcd for C21H24Au2N2: C, 36.1;
H, 3.5. Found: C, 36.0; H, 3.3.
[(t-Bu CtCAu )2(µ-CNC6Me4NC)]. A mixture of t-BuCtCAu
(0.10 g, 0.36 mmol) and CNC6Me4NC (33 mg, 0.18 mmol) in
dichloromethane (10 mL) was stirred for 30 min. The solvent
was then removed completely, and the residue was washed
with hexane to give a light yellow solid. The solid was collected
by filtration, washed with hexane, and dried. Yield: 110 mg,
83%. NMR (CDCl3): δ(1H) ) 1.28 (s, 18H, Bu), 2.36 (s, 12H,
Me). IR (Nujol): 2205 (s), 2124 (sh), 2045 (br, w) cm-1. Anal.
Calcd for C24H30Au2N2: C, 38.9; H, 4.1. Found: C, 38.8; H,
4.0.
Au2(CtCC6H4C6H4CtC) (0.10 g, 0.17 mmol) and CNC6H4NC
(22 mg, 0.17 mmol) in dichloromethane (60 mL) was stirred
for 36 h to give a yellow precipitate. The solid was collected
by filtration, washed with dichloromethane, THF, and ether,
and dried. Yield: 0.11 g, 90%. The solid is insoluble in
common organic solvents. IR (Nujol): 2205 (s) cm-1
. Anal.
Calcd for C24H12Au2N2: C, 39.9; H, 1.7. Found: C, 40.5; H,
2.1.
[(Au CtCC6H4C6H4CtCAu CNC6H3MeNC)x]. A mixture
of Au2(CtCC6H4C6H4CtC) (0.10 g, 0.17 mmol) and CNC6H3-
MeNC (25 mg, 0.18 mmol) in dichloromethane (50 mL) was
stirred for 48 h to give a yellow precipitate. The solid was
collected by filtration, washed with dichloromethane and ether,
and dried. Yield: 0.ll g, 88%. The solid is insoluble in common
organic solvents. IR (Nujol): 2201 (s), 2121 (sh) cm-1. Anal.
Calcd for C25H14Au2N2: C, 40.8; H, 1.9. Found: C, 40.7; H,
2.3.
[(Au CtCC6H4C6H4CtCAu CNC6Me4NC)x]. A mixture of
Au2(CtCC6H4C6H4CtC) (0.10 g, 0.17 mmol) and CNC6Me4-
NC (32 mg, 0.17 mmol) in dichloromethane (60 mL) was stirred
for 48 h to give a yellow precipitate. The solid was collected
by filtration, washed with dichloromethane and ether, and
dried. Yield: 0.l2 g, 91%. The solid is insoluble in common
organic solvents. IR (Nujol): 2209 (s), 2113 (sh), 2021 (w)
cm-1. Anal. Calcd for C28H20Au2N2: C, 43.2; H, 2.6. Found:
C, 43.9; H, 2.9.
[ ( A u C t C C 6 H 4 C 6
H 4 C t C A u C N - 2 , 2 ′ , 6 , 6 ′ - M e 2 -
C6H2Me2C6H2NC)x]. A mixture of Au2(CtCC6H4C6H4CtC)
(0.10 g, 0.17 mmol) and CN-2,2′,6,6′-Me2C6H2Me2C6H2NC (45
mg, 0.17 mmol) in dichloromethane (60 mL) was stirred for
48 h to give a yellow precipitate. The solid was collected by
filtration, washed with THF, dichloromethane and ether, and
dried. Yield: 0.l3 g, 89%. The solid is insoluble in common
organic solvents. IR (Nujol): 2195 (s), 2121 (sh), 2020 (br, w)
cm-1. Anal. Calcd for C34H24Au2N2: C, 47.8; H, 2.8, N, 3.3.
Found: C, 46.8; H, 2.4; N, 3.0.
[(Au CtCC6H2Me2CtCAu CNC6H4NC)x]. A mixture of
Au2(CtCC6H2Me2CtC) (0.10 g, 0.18 mmol) and CNC6H4NC
(24 mg, 0.19 mmol) in dichloromethane (60 mL) was stirred
for 36 h to give a yellow precipitate. The solid was collected
by filtration, washed with dichloromethane, THF, and ether,
and dried. Yield: 113 mg, 93%. The solid is insoluble in
common organic solvents. IR (Nujol): 2207 (s), 2120 (sh), 2010
cm-1. Anal. Calcd for C20H12Au2N2: C, 35.6; H, 1.4. Found:
C, 34.9; H, 1.5.
[(Au CtCC6H2Me2CtCAu CNC6H3MeNC)x]. A mixture of
Au2(CtCC6H2Me2CtC) (0.10 g, 0.18 mmol) and CNC6H3MeNC
(27 mg, 0.19 mmol) in dichloromethane (60 mL) was stirred
for 48 h to give a yellow precipitate. The solid was collected
by filtration, washed with dichloromethane and ether, and
dried. Yield: 116 mg, 92%. The solid is insoluble in common
organic solvents. IR (Nujol): 2205 (s), 2122 (sh) cm-1. Anal.
Calcd for C21H14Au2N2: C, 36.6; H, 2.0. Found: C, 36.3; H,
2.2.
[(Au CtCC6H2Me2CtCAu CNC6Me4NC)x]. A mixture of
Au2(CtCC6H2Me2CtC) (0.10 g, 0.18 mmol) and CNC6Me4NC
(35 mg, 0.19 mmol) in dichloromethane (60 mL) was stirred
for 48 h to give a yellow precipitate. The solid was collected
by filtration, washed with dichloromethane and ether, and
dried. Yield: 0.l2 g, 91%. The solid is insoluble in common
organic solvents. IR (Nujol): 2207 (s) cm-1. Anal. Calcd for
[(t-Bu CtCAu )2(µ-CN-2,2′,6,6′-Me2C6H2Me2C6H2NC)]. A
mixture of t-BuCtCAu (0.10 g, 0.36 mmol) and CN-2,2′,6,6′-
Me2C6H2Me2C6H2NC (47 mg, 0.18 mmol) in dichloromethane
(10 mL) was stirred for 30 min. The solvent was then removed
completely, and the residue was washed with hexane to give
a light yellow solid. The solid was collected by filtration,
washed with hexane, and dried. Yield: 126 mg, 86%. NMR
(CDCl3): δ(1H) ) 1.28 (s, 18H, Bu), 2.45 (s, 12H, Me), 7.30
(br, 4H, Ph). IR (Nujol): 2193 (s), 2119 (sh), 2025 (br, w) cm-1
.
Anal. Calcd for C30H34Au2N2: C, 44.1; H, 4.2. Found: C, 43.4;
H, 3.8.
[(ClAu )2(µ-CNC6H2(t-Bu )2NC)]. AuCl(SMe2) (0.0912 g,
0.310 mmol) was dissolved in dichloromethane (50 mL). To
the solution was then added p-CNC6H2(t-Bu)2NC (0.0385 g,
0.160 mmol). The resulting mixture was stirred overnight to
give a cloudy solution. The solvent was removed completely,
and the residue washed with ether to give a white solid. The
solid was collected by filtration, washed with ether, and
pentane and dried. Yield: 207 mg, 95%. IR (Nujol):: ν(NC)
) 2202 cm-1
. Anal. Calcd for C16H20Au2N2Cl2: C, 27.3; H,
2.9; N, 4.0. Found: C, 27.5; H, 2.9; N, 3.9.
[(t-Bu CtCAu )2(µ-CNC6H 2(t-Bu )2NC)].
A mixture of
t-BuCtCAu (0.0948 g, 0.341 mmol) and CNC6H2(t-Bu)2NC (45
mg, 0.188 mmol) in dichloromethane (60 mL) was stirred for
30 min. The solvent was then removed completely, and the
residue was washed with hexane to give a light yellow solid.
The solid was collected by filtration, washed with hexane, and
dried. Yield: 249 mg, 92%. 1H NMR (CDCl3): δ 1.280 (s, 18H,
t-Bu), 1.415 (s, 18H, t-Bu), 7.495 (s, 2H, Ph). IR (Nujol): 2202
(s) cm-1
. Anal. Calcd for C28H38Au2N2: C, 42.2; H, 4.8, N,
3.5. Found: C, 42.6; H, 4.3; N, 3.3.
[(P h CtCAu )2(µ-CNC6H 2(t-Bu )2NC)]. A mixture of Ph-
CtCAu (0.0892 g, 0.299 mmol) and CNC6H2(t-Bu)2NC (36.5
mg, 0.152 mmol) in dichloromethane (50 mL) was stirred for
30 min. The solvent was then removed completely, and the
residue was washed with hexane to give a light yellow solid.
The solid was collected by filtration, washed with pentane and
hexane and dried. Yield: 225 mg, 90%. 1H NMR (CDCl3): δ
C
24H20Au2N2: C, 39.5; H, 2.8. Found: C, 39.0; H, 2.8.
[ ( Au C tC C 6 H 2 M e 2 Au C N -2 , 2 ′, 6 , 6 ′-M e 2 C 6 H 2 M e 2 -
C6H2NC)x]. A mixture of Au2(CtCC6H2Me2CtC) (0.10 g, 0.18
mmol) and CN-2,2′,6,6′-Me2C6H2Me2C6H2NC (50 mg, 0.19
mmol) in dichloromethane (60 mL) was stirred for 48 h to give
a yellow precipitate. The solid was collected by filtration,
washed with THF, dichloromethane and ether, and dried.
Yield: 0.l3 g, 90%. The solid is insoluble in common organic
solvents. IR (Nujol): 2195 (s), 2121 (sh), 2020 (w) cm-1. Anal.
Calcd for C30H24Au2N2: C, 44.7; H, 3.0. Found: C, 44.4; H,
2.8.
1.463 (s, 18H, Bu), 7.30 (m, 5H, Ph). IR (Nujol): 2204 (s) cm-1
.
Anal. Calcd for C32H30Au2N2: C, 45.9; H, 3.6, N, 3.3. Found:
C, 45.3; H, 4.0; N, 3.5.
[(Au CtCC6H4C6H4CtCAu CNC6H4NC)x]. A mixture of

54 Organometallics, Vol. 15, No. 1, 1996
Irwin et al.
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 3f
Ta ble 2. Atom ic Coor d in a tes (×104) a n d
Equ iva len t Isotr op ic Disp la cem en t P a r a m eter s,
U(eq) (Å2 × 103), for 3f
C32H30Au2N2
T ) 223(2) K
λ ) 0.710 73 Å
a ) 16.734(2) Å
c ) 10.160(2) Å
V ) 2845.0(8) Å3
Z ) 4
fw ) 836.51
space group P42/n (No. 86)
F(obsd) ) 1.94(2) Mg/m3
F(calc) ) 1.906 Mg/m3
µ ) 10.074 mm-1
atom
x
y
z
U(eq)
Au(1)
C(1)
1685(1)
2111(10)
2398(10)
2748(9)
3031(10)
3360(11)
3386(12)
3195(13)
2861(12)
1166(10)
882(8)
437(8)
48(8)
412(8)
845(10)
465(11)
755(13)
1719(10)
2014(1)
965(11)
330(12)
872(1)
1340(14)
1599(16)
1878(16)
900(18)
1159(22)
2411(20)
3442(22)
3157(20)
345(16)
72(1)
70(5)
79(5)
72(5)
111(6)
126(8)
130(8)
151(9)
121(7)
69(5)
66(4)
50(4)
53(4)
49(4)
72(5)
127(8)
35(9)
37(9)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
a
R1 ) 0.0467
-462(10)
-954(10)
-1682(12)
-1912(13)
-1437(14)
-707(12)
3034(10)
3608(8)
4337(8)
4557(9)
4776(8)
4576(10)
3834(12)
5215(12)
4435(13)
b
wR2 ) 0.0926
a
b
2
2
R1 ) ∑(|Fo|- |Fc||)/∑|Fo|. wR2 ) [{∑w(|Fo | - |Fc |)2})/
∑w|Fo | ]0.5
.
2 2
[(Au CtCC6H 4CtCAu CNC6H 2(t-Bu )2NC)x]. A mixture
of Au2(CtCC6H4CtC) (0.0986 g, 0.191 mmol) and CNC6H2(t-
Bu)2NC (47 mg, 0.195 mmol) in dichloromethane (60 mL) was
stirred for 48 h to give a yellow precipitate. The solid was
collected by filtration, washed with THF, dichloromethane and
ether, and dried. Yield: 0.l298 g, 90%. The solid is insoluble
in common organic solvents. IR (Nujol): 2200 (s), 2121 (sh),
2020 (w) cm-1. Anal. Calcd for C26H24Au2N2: C, 41.2; H, 3.2;
N, 3.7. Found: C, 41.2; H, 3.4; N, 3.7.
N(1)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
62(13)
-43(13)
1092(12)
-1206(12)
-2477(15)
-3013(16)
-3493(16)
-2283(17)
[(Au CtCC6H2Me2CtCAu CNC6H2(t-Bu )2NC)x]. A mix-
ture of Au2(CtCC6H2Me2CtC) (0.0923 g, 0.169 mmol) and
CNC6H2(t-Bu)2NC (41.4 mg, 0.172 mmol) in dichloromethane
(60 mL) was stirred for 48 h to give a yellow precipitate. The
solid was collected by filtration, washed with THF, dichlo-
romethane and ether, and dried. Yield: 0.l178 g, 89%. The
solid is insoluble in common organic solvents. IR (Nujol): 2198
(s), 2121 (sh), 2020 (w) cm-1. Anal. Calcd for C28H28Au2N2:
C, 42.7; H, 3.6; N, 3.6. Found: C, 42.7; H, 3.8; N, 3.5.
[(Au CtCC6H4C6H4CtCAu CNC6H2(t-Bu )2NC)x]. A mix-
ture of Au2(CtCC6H4C6H4CtC) (0.0916 g, 0.177 mmol) and
CNC6H2(t-Bu)2NC (43.5 mg, 0.181 mmol) in dichloromethane
(55 mL) was stirred for 48 h to give a yellow precipitate. The
solid was collected by filtration, washed with THF, dichlo-
romethane, and ether, and dried. Yield: 0.l3 g, 88%. The solid
is insoluble in common organic solvents. IR (Nujol): 2196 (s),
2121 (sh), 2020 (w) cm-1. Anal. Calcd for C32H28Au2N2: C,
46.1; H, 3.4; N, 3.4. Found: C, 46.2; H, 3.3; N, 3.3.
[(Au CtCCH2OC6H4C(Me)2-C6H4OCH2CtCAu CNC6H2(t-
Bu )2NC)x]. A mixture of Au2(CtCCH2OC6H4C(Me)2OCH2CtC)
(0.1083 g, 0.156 mmol) and CNC6H2(t-Bu)2NC (39.2 mg, 0.163
mmol) in CH2Cl2 (50 mL) was stirred for 48 h to give a yellow
precipitate. The solid was collected by filtration, washed with
THF, dichloromethane and ether, and dried. Yield: 0.14 g,
95%. The solid is insoluble in common organic solvents. IR
(Nujol): 2195 (s), 2121 (sh), 2029 (w) cm-1. Anal. Calcd for
total 3193 reflections were collected in the 2θ range 2.35-
24.99° (-19 e h e 1, -1 e k e 19, -12 e l e 1) in ω scan
mode at variable scan speeds (2-30 deg/min). Moving back-
ground measurements were made at 25% extensions of the
scan range. The data were processed (XCAD4) and corrected
for absorption by the Gaussian integration method SHELX-
76.24b The minimum and the maximum transmission factors
are 0.0181 and 0.1044. respectively. Solution and initial
refinements were done using the SHELXTL-PC24c programs.
The molecule occupies Wyckoff position d and lies upon a
center of symmetry. Final refinements were carried out using
SHELXL-93.24d Anisotropic thermal parameters were as-
signed and refined for the Au, N, and C atoms of the
diisocyanide ligand. All other phenyl rings were constrained
to have 2-fold symmetry. All 15 hydrogen atoms in the
molecule were placed in the calculated positions, and they were
included in structure factor calculations. A common thermal
parameter was assigned for all hydrogen atoms and refined
in the least-squares cycles. In the final full-matrix refinements
on F2, the model converged at R1 ) 0.0467, wR2 ) 0.1348, and
Goof ) 1.011 for 1040 observations with Fo g 4σ(Fo), 143
parameters, and 8 restraints. The maximum shift/esd ) 0.076
for U12 of C(2) and the maximum shift ) 0.004 Å for H(14A).
The electron density in the final difference Fourier synthesis
ranges from 0.89 to -0.59 e Å-3; the top seven peaks were
associated with gold at distances of 0.95-1.27 Å. The posi-
tional and U(equiv) thermal parameters are given in Table 2,
and hydrogen atom parameters are available as Supporting
Information, Table S1.
C
37H38Au2N2O2: C, 47.7; H, 4.1; N, 3.0. Found: C, 47.9; H,
4.0; N, 2.8.
Cr ysta llogr a p h ic An a lysis for (P h CtCAu )2(CNC6H2-
(t-Bu )2NC). Crystallographic data are summarized in Table
1. Pale-yellow, rodlike crystals were grown by diffusion of CH3-
CN into a solution of the complex in CH2Cl2 at 4 °C. The
density (1.94 g mL-1) was determined by the neutral buoyancy
method using a mixture of carbon tetrachloride and bromo-
form. The diffraction experiments were carried out on an
Enraf Nonius CAD4F diffractometer using the CAD4 EX-
PRESS software package24a and graphite-monochromated Mo
KR radiation. Data collection was performed at -50 °C on a
crystal of size 0.11 × 0.11 × 0.37 mm mounted in air. The
cell constants were obtained by centering 24 high-angle
reflections (25.7 e 2θ e 26.3°), and Laue symmetry 4/m was
confirmed by merging equivalent reflections. The tetragonal
space group P42/n with Z ) 4 was unambiguously assigned
on the basis of systematic absences (hk0, h + k odd; 00l, l odd;
h00, h ) odd). During data collection three standards were
monitored every 2 h, and showed no appreciable decay. In
Resu lts a n d Discu ssion
Syn th esis of P r ecu r sor s a n d th e Mod el Rea c-
tion s. Monomeric alkynyl(isocyanide)gold(I) complexes
of the type RCtCAuCNR′ can be prepared by either the
reactions of [AuX(CNR′)] with alkynyllithium or Grig-
nard reagents (eq 1, M ) Li or MgX)25 or the reaction
of (AuCtCR)x with CNR′ (eq 2).18 Thus it is expected
that polymeric compounds can be similarly produced
from the reaction of a linear dinuclear gold(I) diisocya-
nide complex XAuCNR′NCAuX with a difunctionalized
linear organolithium or Grignard reagent (eq 3) or the
reaction of a linear dinuclear gold(I) diacetylide complex
(AuCtCRCtCAu)x with a linear diisocyanide (eq 4).
In order to produce a high polymer, the polymeriza-
tion reaction must be of high yield (essentially no side
(24) (a) CAD4 Express, Enraf-Nonius X-Ray Instruments Inc. 1990.
(b) Sheldrick, G. M. SHELX-76, University of Cambridge, England,
1976. (c) Sheldrick, G. M. SHELXTL-PC 4.2, Siemens Analytical X-Ray
Instruments Inc., Madison, 1990. (d) Sheldrick, G. M., SHELXL-93,
Institut fu¨r Anorg. Chemie, Go¨ttingen, Germany, 1993.
(25) Puddephatt, R. J .; Treurnicht, I. J . Organomet. Chem. 1987,
319, 129.

Model Compounds with Gold(I) Centers
Organometallics, Vol. 15, No. 1, 1996 55
AuX(CNR′) + RCtCM f RCtCAuCNR′ + MX (1)
(AuCtCR)x + CNR′ f RCtCAuCNR′
nXAuCNR′NCAuX + nMCtCRCtCM f
(2)
2nMX + (AuCNR′NCAuCtCRCtC-)n (3)
F igu r e 1. View of the molecule [Au2(CtCPh)2(µ-CtN-
(t-Bu)2C6H2NtC)], 3f, with the atom-labeling scheme.
nAuCtCRCtCAu + nCNR′NC f
(AuCNR′NCAuCtCRCtC-)n (4)
observed at 2211 cm-1 for 2b and at 2220 cm-1 for 2c.
For comparison the ν(NtC) stretching frequency is at
2116 cm-1 for the free ligand. The increase (ca. 100
cm-1) in the CN stretching frequency of coordinated
isocyanide is attributed to the σ donation of the anti-
bonding carbon lone pair (in the 7a1 orbital) to gold upon
complexation.28 The very weak bands which appeared
between 2000-2170 cm-1 are likely to be due to ν(CtC).
Linear dinuclear complexes could also be prepared
easily from the reaction of mononuclear gold acetylide
complex and a diisocyanide as illustrated by the reaction
of 2 equiv of either t-BuCtCAu or PhCtCAu with para-
substituted diisocyanoarenes to give 3 (eq 7). The
reactions and fast). Thus reaction 4 is an ideal reaction
for preparation of polymers since such reactions are
usually very fast and quantitative and no side products
are produced. Besides the delicate reaction conditions,
side reactions might occur in reaction 3 since coordi-
nated isocyanides are very reactive toward nucleophilic
reagents and reactions of isocyanides coordinated to
gold(I) are well-known.12,26 The possibility of using
reaction 3 to prepare polymers has therefore not been
investigated in detail in this study.
The yellow complexes (AuCtCRCtCAu)x, 1, (R )
C6H4, C6H4C6H4, 2,5-C6H2Me2, CH2OC6H4C(Me)2C6H4-
OCH2) are produced from the essentially quantitative
reaction of 2 equiv of [AuCl(SMe2)] with the appropriate
diethynylarenes in the presence of sodium acetate as a
base in the mixed solvents THF/MeOH (eq 5). These
complexes are stable yellow powders which are insoluble
in common organic solvents. The υ(CtC) bands in the
infrared spectra were observed as weak bands around
2000 cm-1
. These digold complexes are similar in
reaction is also essentially quantitative and appears to
be complete in a few minutes. The H NMR spectra of
appearance to phenylethynylgold(I), which is proposed
to be a coordination polymer. The digold diacetylides
are likely also polymeric in nature. To our knowledge,
similar dinuclear gold acetylide complexes are rare,7
although the explosive gold(I) acetylide Au2C2 was
reported in 1900.27
The diacetylide complexes react readily with 2,6-
dimethylphenyl isocyanide (XyNtC) to give the di-
nuclear isocyanide complexes 2 in high yield (eq 6). The
pale yellow isocyanide complexes were characterized by
elemental analysis, 1H NMR, and IR spectroscopy. The
1H NMR spectra display characteristic resonances for
the aromatic protons in the region 7.1-7.6 ppm and for
the methyls on the aromatic rings in the region 2.41-
2.45 ppm. The strong bands due to ν(NtC) were
1
3 display resonances assignable to the alkynyl group
at around 1.27 ppm, R ) t-Bu, or 7.35 ppm, R ) Ph,
and the expected resonances of the diisocyanide ligands.
The strong IR bands due to ν(NtC) were observed
between 2194 and 2211 cm-1
. As expected the CN
stretching frequencies of the diisocyanide ligands are
about 90 cm-1 higher than that for the free ones. In
addition to the strong bands for υ(CN), there are also
weak shoulders around 2120 cm-1 and a very broad and
weak band around 2040 cm-1 in the IR spectra. These
bands could be assigned to υ(CtC). The structure of
one binuclear complex is described below.
Descr ip t ion of t h e St r u ct u r e of P h CtCAu -
CNC6H2(t-Bu )2CAu CNCtCP h . The molecular struc-
ture of [PhCtCAuCtN-C6H2(t-Bu)2-NtCAuCtCPh],
3f, is shown in Figure 1, and selected bond lengths and
(26) Fehlhammer, W. P.; Finck, W. J . Organomet. Chem. 1991, 414,
261.
(27) (a) Matthews, J . A.; Watters, L. L. J . Am. Chem. Soc. 1990, 22,
108. (b) Vicente, J .; Chicote, M.-T.; Abrisqueta, M.-D. J . Chem. Soc.,
Dalton Trans. 1995, 497.
(28) Sarapu, A. C.; Fenske, R. F. Inorg. Chem. 1975, 14, 247.

56 Organometallics, Vol. 15, No. 1, 1996
Irwin et al.
Ta ble 3. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 3fa
Au(1)-Au(1)1
Au(1)-C(9)
C(2)-C(3)
3.1745(13)
1.99(2)
1.48(2)
1.38(2)
1.33(2)
1.38(2)
1.43(2)
1.39(2)
1.36(2)
1.49(2)
1.49(2)
Au(1)-C(1)
C(1)-C(2)
1.95(2)
1.20(2)
1.38(2)
1.36(2)
1.35(2)
1.11(2)
1.37(2)
1.36(2)
1.52(2)
1.50(2)
C(3)-C(4)
C(3)-C(8)
C(4)-C(5)
C(6)-C(7)
C(9)-N(1)
C(10)-C(11)
C(11)-C(12)2
C(12)-C(13)
C(13)-C(14)
C(5)-C(6)
C(7)-C(8)
N(1)-C(10)
C(10)-C(12)
C(12)-C(11)2
C(13)-C(16)
C(13)-C(15)
C(9)-Au(1)-C(1)
C(1)-Au(1)-Au(1)1
C(1)-C(2)-C(3)
C(2)-C(3)-C(8)
C(5)-C(4)-C(3)
C(5)-C(6)-C(7)
C(7)-C(8)-C(3)
C(9)-N(1)-C(10)
C(11)-C(10)-N(1)
175.0(6) C(9)-Au(1)-Au(1)1
98.5(5) C(2)-C(1)-Au(1)
178((2) C(2)-C(3)-C(4)
120((2) C(4)-C(3)-C(8)
122((2) C(4)-C(5)-C(6)
124((3) C(8)-C(7)-C(6)
121((2) N(1)-C(9)-Au(1)
168((2) C(11)-C(10)-C(12)
114((1) C(12)-C(10)-N(1)
86.3(5)
178((2)
122((2)
117((2)
117((2)
117((2)
179((1)
124((1)
122((1)
F igu r e 2. Two views of the packing of the molecules of
3f, showing the zigzag chain structure with (a) π-stacking
of aryl groups and (b) short intermolecular Au‚‚Au contacts.
C(12)2-C(11)-C(10) 124((1) C(11)2-C(12)-C(10) 112((1)
and this value is significantly shorter than that of
3.252(1) Å found in a related diphosphine complex.31 The
bowing of the isocyanide ligands appears to allow a
closer Au‚‚Au contact than would otherwise be possible,
and this may account for the significant distortion from
linearity observed.10,12 The evidence for π-stacking is
less clear-cut. The dihedral angle between nearest aryl
groups of the phenylethynyl and diisocyanoarene groups
is 20.8°, the distance between the ring centroids is 4.35
Å, and the closest intermolecular C‚‚C contact is
C(4A)‚‚C(12) ) 3.905 Å. Any bonding interactions at
such distances are presumed to be weak.30 If the Au‚‚-
Au interactions are strong enough to allow easy electron
migration (it is not obvious if this is so), crystals of the
complex may be expected to have some electrical
conductivity along the chain direction in the solid state,
but studies require larger crystals than have yet been
grown.
Syn th esis of P olym er s. Reactions of the linear
digold complexes AuCtCRCtCAu (R ) C6H4, C6H4C6H4,
C6H2Me2, and CH2OC6H4C(Me)2C6H4OCH2) with ap-
propriate para-substituted diisocyanoarenes in dichlo-
romethane produced a series of polymers 4, as illus-
trated in eq 8. All the products are air-stable yellow
powders which are insoluble in common organic sol-
vents.
C(11)2-C(12)-C(13) 122((1) C(10)-C(12)-C(13)
C(16)-C(13)-C(12)
C(12)-C(13)-C(14)
C(12)-C(13)-C(15)
126((1)
109((2)
108((2)
107((2)
113((1) C(16)-C(13)-C(14)
107((1) C(16)-C(13)-C(15)
112((1) C(14)-C(13)-C(15)
a
Symmetry transformations used to generate equivalent at-
oms: (1) -x + 1/2, -y + 1/2, z; (2) -x, -y + 1, -z.
angles are presented in Table 3. The molecule has the
predicted rodlike structure and possesses a center of
symmetry at the center of the diisocyanide ligand. The
angles which are expected to be 180° in an ideal linear
complex, namely C(1)-Au(1)-C(9), Au(1)-C(9)-N(1),
C(9)-N(1)-C(10), Au(1)-C(1)-C(2), and C(1)-C(2)-
C(3), are 175.0(6), 179(1), 168(2), 178(2), and 178(2)°,
respectively. The only large deviation from the ideal
value is the C(9)-N(1)-C(10) angle of 168(2)°. Similar
bowing of the isocyanide ligand has been reported for
other coordinated isocyanides,10,29 but the distortion is
greater than in the other known gold(I) isocyanide
complexes in which the angle CsNtC ranges from 170
to 180°.10,29 Overall, the ligand appears well suited to
act as a linear bridge in the the desired rigid-rod
polymers. Other features of the molecule are normal;
for example, the AusC distances in the AusCN or
AusCtC units of 1.99(2) and 1.95(2) Å, respectively,
fall in the usual ranges for such groups.10,12-16
The polymers 4 are characterized primarily by el-
emental analysis and IR spectroscopy. In particular,
the polymeric species display IR spectral properties
similar to those of the model complexes. The values of
ν(NtC) of the diisocyanide ligands are observed around
2200 cm-1 and are about 90 cm-1 higher than that for
the free ones. Since all the ligands are linear and the
geometry around Au is also linear, these polymers
presumably have a linear structure. The insolubility
makes it impossible to determine the molecular weights
of the polymers. The Au‚‚Au interaction established for
the model complex, even with bulkiest t-butyl substit-
uents, suggests that the polymers of this type, regard-
less of the organic substituents present, will also have
interchain Au‚‚Au contacts. This leads to virtual
crosslinking and so may account in part for the low
solubility of the polymers in common organic solvents.
Although individual Au‚‚Au attractions are expected to
The most interesting feature of the structure of 3f is
the packing of the molecules in the lattice. This is
shown in two perspectives in Figure 2. It can be seen
that the rodlike molecules are packed in zigzag chains
to give what may be considered a loosely held polymeric
structure. The attractive forces between neighboring
molecules appear to be due to short Au‚‚Au contacts10,12
and π-stacking of aryl groups.30 This occurs despite the
presence of bulky tert-butyl groups on the diisocyanide
ligand. The intermolecular gold-gold contacts of
3.174(1) Å fall within the normal range of ca. 2.75-3.40
Å for Au‚‚Au bonds between neighboring gold(I) centers,
(29) (a) Che, C. M.; Wong, W. T.; Lai, T. F.; Kwong, H. L. J . Chem.
Soc., Chem. Commun. 1989, 243. (b) Bos, W.; Kanters, R. P. F.; van
Halen, C. J .; Bosman, W. P.; Behm, H.; Smits, J . J . M.; Beurskens, P.
T.; Bour, J . J .; Pignolet, L. H. J . Organomet. Chem. 1986, 307, 385. (c)
Perrault, D.; Drouin, M.; Michel, A.; Harvey, P. D. Inorg. Chem. 1991,
30, 4. (d) Eggleston, D. S.; Chodosh, D. F.; Webb, R. L.; Davis, L. L.
Acta Crystallogr. 1986, C42, 36. (e) Che, C. M.; Yip, H. K.; Wong, W.
T.; Lai, T. F. Inorg. Chim. Acta 1992, 197, 177. (f) Esperas, S. Acta
Chem. Scand. 1976, 23, 101.
(31) Shieh, S.-J .; Hong, X.; Peng, S.-M.; Che, C.-M. J . Chem. Soc.,
Dalton Trans. 1994, 3067.
(30) Hunter, C. A. Chem. Soc. Rev. 1994, 23, 101.

Model Compounds with Gold(I) Centers
Organometallics, Vol. 15, No. 1, 1996 57
Ta ble 4. Gold 4f(7/2) Bin d in g En er gies in
Alk yn ylgold (I) Com p lexes a n d P olym er s
binding
compound
energy, eV
PhCtCAuCNC6H2(t-Bu)2CAuCNCtCPh, 3f
(AuCtC-(C6H4)2CtCAuCNC6H3MeNC-)x, 4b
(AuCtC-(C6H4)2CtCAuCNC6Me4NC-)x, 4c
(AuCtCC6H2Me2CtCAuCNC6H3MeNC-)x, 4g
(AuCtCC6H2Me2CtCAuCNC6Me4NC-)x, 4h
(AuCtCC6H2Me2CtCAuCNC6H2(tBu)2NC-)x, 4j
(AuCtCC6H4CtCAuCNC6H2(t-Bu)2NC-)x, 4k
85.1
85.3
85.7
85.3
85.1
85.2
85.2
polymers have the same core structures, namely linear
with one alkynyl and one isocyanide ligand at each gold-
(I) center.
The thermal properties of the polymeric compounds,
4, have been studied using differential scanning calo-
rimetry, DSC. Without exception, all of the compounds
display significant endothermic transition over a wide
temperature range 30-170 °C and decomposed around
200 °C before melting.
Con clu sion s
It is shown that binuclear rigid rod complexes of gold-
(I) can form infinite chain structures by formation of
internuclear Au‚‚Au bonding interactions. In principle,
such a structure should be capable of acting as a one-
dimensional conductor in single-crystal form. Routes
to rigid rod polymers with alternating diisocyanide and
diacetylide ligands bridging between gold(I) centers
have also been developed. However, despite efforts to
introduce organic substituents, including t-butyl groups,
as solubility enhancing units, all the polymers prepared
proved to be insoluble. Crosslinking by way of inter-
chain Au‚‚Au bonding, as established in the model
complex 3f, is thought to be at least partly responsible
for the poor solubility.
be weak, the combination of many such attractions
between polymer chains could lead to low solubility,
though it should be emphasized that at present this is
a speculative interpretation and that the gold(I) poly-
mers might be insoluble without such effects. Even the
polymer [(AuCtCC6H2Me2CtCAuCNC6H2(t-Bu)2NC-
Au)x], 4j, which contains several bulky organic groups,
is poorly soluble. Clearly it will be a challenge to obtain
more soluble polymers. The use of extremely bulky
substituents on the aryl spacer groups might give
sufficient solubility, but there are synthetic problems
to overcome.
Ack n ow led gm en t. We thank the NSERC (Canada)
and 3M (Canada) for financial support, the NSERC
(Canada) and OCMR for scholarships to M.J .I., and Drs.
Z. Yuan, M. C. J ennings, and J . J . Vittal for advice and
assistance.
Su p p or tin g In for m a tion Ava ila ble: Tables of anisotro-
pic thermal parameters and hydrogen parameters (2 pages).
Ordering information is given on any current masthead page.
The yellow polymeric compounds, 4, and the dinuclear
model complexes, 2 and 3, display almost identical XPS
parameters. Table 4 contains the binding energies for
Au 4f for several of the compounds described above.
These data are in close agreement with XPS values for
a variety of simple gold-isocyanide compounds32,33 and
confirm that the model compounds and corresponding
OM950659R
(32) Hochella, M. F.; White, A. F. Rev. Mineral. 1990, 23, 525.
(33) Bancroft, G. M.; J ean, G. E. Geochim. Cosmochim. Acta 1985,
49, 979.