[Au(CN)4]- as a supramolecular building block for heterobimetallic coordination polymers

Article abstract of DOI:10.1021/ic0341441

A series of the first coordination polymers using the [Au(CN)₄]^- anion as a building block has been prepared. The planar tetracyanoaurate anion uses one, two, or four cyano groups to bridge to Ni(II) or Cu(II) centers and exhibits weak Au(III)-N(cyano) interactions between anions. Ni(en)₂[Au(CN)₄]₂·H₂O (1, en = ethylenediamine) is a molecular compound with the two [Au(CN)₄]^- anions coordinating in a trans orientation to Ni(II) without further cyanide coordination. Cu(dien)[Au(CN)₄]₂ (2, dien = diethylenetriamine) forms a similar molecular complex; however, the dimensionality is increased through weak intermolecular Au-N(cyano) interactions of 3.002(14) A to form a 1-D zigzag chain. Cu(en)₂[Au(CN)₄]₂ (3) also forms a molecular complex similar to 1, but with elongated axial bonds. The complex further aggregates through Au-N(cyano) interactions of 3.035(8) A to form a 2-D array. In [Cu(dmeda)₂Au(CN)₄][Au(CN)₄] (4, dmeda = N,N-dimethylethylenediamine) one [Au(CN)₄]^- anion coordinates via two cis-N(cyano) donors to the axial sites of two Cu(II) centers to form a 1-D zigzag chain of alternating [Cu(dmeda)₂]²⁺ and [Au(CN)₂]^- units; the other [Au(CN)₄]^- anion forms a 1-D chain via Au-N(cyano) interactions. In [Cu(bipy)- (H₂O)₂(Au(CN)₄)_0.5][Au (CN)₄]_1.5 (5, bipy = 2,2′-bipyridine) one [Au(CN)₄]^- anion uses all four cyano moieties to bridge four different CU(II) centers, creating a 1-D chain.

Full text of DOI:10.1021/ic0341441

Inorg. Chem. 2003, 42, 3917−3924
-
[
Au(CN) ] as a Supramolecular Building Block for Heterobimetallic
4
Coordination Polymers
Carolyn J. Shorrock, Howard Jong, Raymond J. Batchelor, and Daniel B. Leznoff*
Department of Chemistry, Simon Fraser UniVersity, 8888 UniVersity DriVe,
Burnaby, British Columbia V5A 1S6, Canada
Received February 11, 2003
A series of the first coordination polymers using the [Au(CN) -
planar tetracyanoaurate anion uses one, two, or four cyano groups to bridge to Ni(II) or Cu(II) centers and exhibits
weak Au(III)−N(cyano) interactions between anions. Ni(en) [Au(CN) ‚H O (1, en ) ethylenediamine) is a molecular
] anions coordinating in a trans orientation to Ni(II) without further cyanide
(2, dien ) diethylenetriamine) forms a similar molecular complex; however, the
dimensionality is increased through weak intermolecular Au−N(cyano) interactions of 3.002(14) Å to form a 1-D
zigzag chain. Cu(en) [Au(CN) (3) also forms a molecular complex similar to 1, but with elongated axial bonds.
] anion as a building block has been prepared. The
4
2
4
]
2
2
-
compound with the two [Au(CN)
coordination. Cu(dien)[Au(CN)
4
4 2
]
2
4 2
]
The complex further aggregates through Au−N(cyano) interactions of 3.035(8) Å to form a 2-D array. In
-
[
Cu(dmeda)
2
Au(CN)
4
][Au(CN)
4
] (4, dmeda ) N,N-dimethylethylenediamine) one [Au(CN)
4
] anion coordinates via
2+
2
two cis-N(cyano) donors to the axial sites of two Cu(II) centers to form a 1-D zigzag chain of alternating [Cu(dmeda) ]
]- units; the other [Au(CN)
] anion forms a 1-D chain via Au−N(cyano) interactions. In [Cu(bipy)-
]- anion uses all four cyano moieties to
-
and [Au(CN)
O) (Au(CN)
bridge four different Cu(II) centers, creating a 1-D chain.
2
4
(H
2
2
4
)0.5][Au(CN) 1.5 (5, bipy ) 2,2′-bipyridine) one [Au(CN)
4
]
4
Introduction
of supramolecular chemistry,7,8 as highly dimensional sys-
tems have the potential to produce interesting and useful
Square planar complexes are commonly formed by transi-
tion metal ions having a d electron configuration, such as
9
10
properties such as magnetism, nonlinear optics, conduc-
8
1
1
12
tion, or porosity.
Pt(II), Pd(II), and Ni(II). Such planar complexes, especially
those of platinum(II), can sometimes form metal-metal
stacking interactions with metal-metal distances as low as
Cyanometalate anions have been extensively used as
design elements in supramolecular coordination systems
1,2
8
8
3
.1 Å. These d -d interactions are thought to be associated
(
6) Shorrock, C. J.; Xue, B.-Y.; Kim, P. B.; Batchelor, R. J.; Patrick, B.
2
with the energetic proximity and interactions of the 5d
z
and
O.; Leznoff, D. B. Inorg. Chem. 2002, 41, 6743.
2
the 6p
z
orbitals. We have previously illustrated the potential
(7) (a) Moulton, B.; Zaworotko, M. J. Chem. ReV. 2001, 101, 1629. (b)
1
0
Holliday, B. J.; Mirkin, C. A. Angew. Chem., Int. Ed. 2001, 40, 2022.
of using d metal-metal interactions to increase dimen-
sionality in systems containing transition metal cations and
Au(I) or Ag(I) cyanide anions.3 Methods of rationally
increasing dimensionality are an important focus in the field
(c) Braga, D. J. Chem. Soc., Dalton Trans. 2000, 3705. (d) Ouahab,
L. Chem. Mater. 1997, 9, 1909 and references therein.
-6
(8) Ohba, M.; Oh kawa, H. Coord. Chem. ReV. 2000, 198, 313.
(
9) (a) Miller, J. S. Inorg. Chem. 2000, 39, 4392. (b) Magnetism: A
Supramolecular Function; Kahn, O., Ed.; Kluwer Academic Publish-
ers: Dordrecht, The Netherlands, 1996. (c) Decurtins, S.; Pellaux, R.;
Antorrena, G.; Palacio, F. Coord. Chem. ReV. 1999, 190-192, 841.
*
Corresponding author. Tel: 1-604-291-4887. Fax: 1-604-291-3765.
E-mail: dleznoff@sfu.ca.
(10) (a) Optoelectronic Properties of Inorganic Compounds; Roundhill,
D. M., Fackler, J. P., Jr., Eds.; Plenum Press: New York, 1999. (b)
Marks, T. J.; Ratner, M. A. Angew. Chem., Int. Ed. Engl. 1995, 34,
155. (c) Coe, B. J. Chem. Eur. J. 1999, 5, 2464.
(
1) Roundhill, D. M. In ComprehensiVe Coordination Chemistry; Wilkin-
son, G., Gillard, R. D., McCleverty, J. A., Eds.; Pergamon Press:
Oxford, 1987; Vol. 5, p 351.
(
(
2) Krogmann, K. Angew. Chem., Int. Ed. Engl. 1969, 8, 35.
3) Leznoff, D. B.; Xue, B.-Y.; Batchelor, R. J.; Einstein, F. W. B.; Patrick,
B. O. Inorg. Chem. 2001, 40, 6026.
(11) (a) Handbook of Conducting Polymers, 2nd ed.; Skotheim, T. A.,
Elsenbaumer, R. L., Reynolds, J. R., Eds.; M. Dekker: New York,
1998. (b) Marguerettaz, X.; Redmond, G.; Rao, S. N.; Fitzmaurice,
D. Chem. Eur. J. 1996, 2, 420. (c) Cassoux, P.; Valade, L.; Kobayashi,
H.; Kobayashi, A.; Clark, R. A.; Underhill, A. E. Coord. Chem. ReV.
1991, 110, 115. (d) Imakubo, T.; Tajima, N.; Tamura, M.; Kato, R.;
Nishio, Y.; Kajita, K. J. Mater. Chem. 2002, 12, 159.
(4) Leznoff, D. B.; Xue, B.-Y.; Patrick, B. O.; Sanchez, V.; Thompson,
R. C. Chem. Commun. 2001, 259.
(5) Leznoff, D. B.; Xue, B.-Y.; Stevens, C. L.; Storr, A.; Thompson, R.
C.; Patrick, B. O. Polyhedron 2001, 20, 1247.
1
0.1021/ic0341441 CCC: $25.00 © 2003 American Chemical Society
Inorganic Chemistry, Vol. 42, No. 12, 2003 3917
Published on Web 05/22/2003

Shorrock et al.
where they can act as multidentate ligands, linking numerous
metal centers together to form stable, high-dimensionality
aqueous solution of KAu(CN)
dropwise to this pale purple solution. The resulting solution was
covered and left undisturbed. Over 2 months, pale purple, X-ray
4
(0.075 g, 0.220 mmol) was added
8
,13,14
coordination polymers with transition metal cations.
Many studies have been done with square planar cyano-
quality crystals of Ni(en)
the solution. Yield: 0.085 g (98%). Anal. Calcd for C12
Au NiO: C, 18.04; H, 2.27; N, 21.04. Found: C, 18.36; H, 2.20;
N, 21.19. IR (KBr): 2214 (νCN), 2202 (νCN), 2190 (νCN), 2180
2
[Au(CN)
4 2 2
] ‚H O (1) were deposited from
2-
2-
18 12
H N -
metalates [Pt(CN)
4
]
4
and [Ni(CN) ] , indicating their
2
usefulness in building multidimensional coordination poly-
1
3,15-20
mers,
including the well-known Hofmann clath-
(
w, νCN), 1600, 1462, 1384, 1320, 1284, 1272, 1089, 1023, 965,
rates.1
3,15
Despite this, the related [Au(CN)
]
-
anion has
4
-1
6
99, 661, 531, 519, 415 cm
Cu(dien)[Au(CN) )]
Cu(ClO ‚6H O (0.030 g, 0.075 mmol) was added a 1 mL stock
solution (0.075 M) of dien. While stirring, a 3 mL aqueous solution
of KAu(CN) (0.051 g, 0.150 mmol) was added dropwise to this
.
received little attention in the field of supramolecular
coordination chemistry. Au(III) is isoelectronic with Pt(II)
and Pd(II) and thus also has the potential of displaying the
aforementioned metal-metal stacking interactions. In light
4
2
(2). To a 2 mL aqueous solution of
4
)
2
2
4
of these issues, we have endeavored to examine the ability
dark blue solution. The resulting solution was covered and left
undisturbed to yield X-ray quality, purple crystals of Cu(dien)-
-
of [Au(CN)
4
] to act as a building block to form hetero-
[
Au(CN)
Calcd for C12
C, 18.58; H, 1.69; N, 19.83. IR (KBr): 2241 (νCN), 2219 (νCN),
4
]
2
(2) over several weeks. Yield: 0.047 g (81%). Anal.
bimetallic coordination polymers.
13 2
H N11Au
Cu: C, 18.75; H, 1.70; N, 20.04. Found:
Experimental Section
2
cm
189 (νCN), 1585, 1317, 1142, 1092, 1028, 974, 653, 526, 419
General Procedures and Physical Measurements. All ma-
nipulations were performed in air using purified solvents. The
KAu(CN) salt, the amine ligands ethylenediamine (en), diethylene-
4
triamine (dien), N,N-dimethylethylenediamine (dmeda), 2,2′-bi-
pyridine (bipy), and all other reagents were obtained from com-
mercial sources and used as received. IR spectra were obtained
using a Thermo Nicolet Nexus 670 FT-IR spectrometer. Thermo-
gravimetric analysis data were collected using a Shimadzu TGA-
-1
.
Cu(en)
Cu(ClO
solution (0.150 M) of en. While stirring, a 3 mL aqueous solution
of KAu(CN) (0.051 g, 0.150 mmol) was added dropwise to this
purple solution. The resulting solution was covered and left
undisturbed to yield X-ray quality, purple crystals of Cu(en)
Au(CN) (3) over several weeks. Yield: 0.043 g (84%). Anal.
Calcd for C12 Cu: C, 18.34; H, 2.05; N, 21.39. Found:
2
[Au(CN)
4 2
] (3). To a 3 mL aqueous solution of
4
)
2
‚6H O (0.028 g, 0.075 mmol) was added a 1 mL stock
2
4
2
-
[
4 2
]
50 instrument in air atmosphere. Microanalyses (C, H, N) were
16 2
H N12Au
performed at Simon Fraser University by Mr. Miki Yang.
Variable-temperature magnetic susceptibility data were collected
using a Quantum Design SQUID MPMS-5S magnetometer working
down to 2 K at 1 T field strength. All data was corrected for TIP,
the diamagnetism of the sample holder, and the constituent atoms
C, 18.15; H, 2.05; N, 21.22. IR (KBr): 2187 (νCN), 2180 (νCN),
-1
1
589, 1462, 1315, 1084, 1037, 973, 702, 533, 413 cm
Cu(dmeda) Au(CN) ][Au(CN)
solution of Cu(ClO ‚6H O (0.041 g, 0.110 mmol) was added a 2
mL stock solution (0.110 M) of dmeda. While stirring, a 3 mL
aqueous solution of KAu(CN) (0.075 g, 0.220 mmol) was added
dropwise to this purple solution. An immediate purple precipitate
of [Cu(dmeda) Au(CN) ][Au(CN) ] (4) formed. The remaining
.
[
2
4
4
] (4). To a 3 mL aqueous
4
)
2
2
(
by use of Pascal constants).21
4
Synthetic Procedures. CAUTION! Although we have experi-
enced no difficulties, perchlorate salts are potentially explosive and
should only be used in small quantities and handled with care.
2
4
4
filtrate was left to evaporate slowly for several days to yield X-ray
quality, purple crystals of 4. Yield: 0.076 g (94%). The powder
and crystals had comparable IR spectra and elemental analyses.
Ni(en)
Ni(NO
neat en (0.220 mmol) using a microsyringe. While stirring, a 5 mL
2
[Au(CN)
4
2 2
] ‚H O (1). To a 5 mL aqueous solution of
3
)
2
‚6H O (0.032 g, 0.110 mmol) was added 0.015 mL of
2
Anal. Calcd for C16
Found: C, 22.63; H, 2.85; N, 19.78. IR (KBr): 2190 (νCN), 3302,
245, 3160, 3023, 2986, 2944, 1598, 1478, 1468, 1462, 1444, 1291,
24 2
H N12Au Cu: C, 22.83; H, 2.87; N, 19.96.
(
12) (a) Eddaoudi, M.; Moler, D. B.; Li, H.; Chen, B.; Reineke, T. M.;
O’Keefe, M.; Yaghi, O. M. Acc. Chem. Res. 2001, 34, 319. (b)
Iwamoto, T. In Inclusion Compounds; Atwood, J. L., Davies, J. E.
D., MacNicol, D. D., Eds.; Oxford University Press: London, U.K.,
3
1190, 1151, 1124, 1062, 1033, 1004, 937, 893, 781, 669, 461, 421,
-1
4
17 cm .
1
991; Vol. 5, p 177. (c) Zaworotko, M. J. Angew. Chem., Int. Ed.
[
Cu(bipy)(H
aqueous solution of an excess of Cu(ClO
mmol) was added a 4 mL methanolic solution of bipy (0.011 g,
.074 mmol). While stirring, a 4 mL aqueous solution of KAu(CN)
0.050 g, 0.147 mmol) was added dropwise to this blue solution.
2
O)
2
(Au(CN)
4
)
0.5][Au(CN)
4
]1.5 (5). To a 4 mL
2000, 39, 3052.
(
(
(
13) Dunbar, K. R.; Heintz, R. A. Prog. Inorg. Chem 1997, 45, 2283 and
)
4 2
‚6H O (0.054 g, 0.147
2
references therein.
14) Vahrenkamp, H.; Geib, A.; Richardson, G. N. J. Chem. Soc., Dalton
Trans. 1997, 3643.
15) Iwamoto, T. In ComprehensiVe Supramolecular Chemistry; Lehn, J.
M., Atwood, J. L., Davies, J. E. D., MacNicol, D. D., Vogtle, F.;
Alberti, G. T. B., Eds.; Pergamon Press: Oxford, 1996; Vol. 7, pp
0
(
4
The solution was covered and cooled for 4 days, then left to
evaporate slowly at room temperature over several weeks to yield
6
43-690 and references therein.
X-ray quality crystals of [Cu(bipy)(H
(5). Yield: 0.061 g (97% based on Au). Anal. Calcd for C18
Au CuO : C, 25.20; H, 1.41; N, 16.33. Found: C, 25.19; H, 1.39;
O) (Au(CN) )0.5][Au(CN) ]
2 2 4 4 1.5
(
16) (a) Knoeppel, D. W.; Shore, S. G. Inorg. Chem. 1996, 35, 1747. (b)
Knoeppel, D. W.; Shore, S. G. Inorg. Chem. 1996, 35, 5328. (c) Gable,
R. W.; Hoskins, B. F.; Robson, R. Chem. Commun. 1990, 762. (d)
Cˇ ern a´ k, J.; Chomi cˇ , J. Acta Crystallogr. 1990, C46, 2103.
17) Maji, T. K.; Mukherjee, P. S.; Mostafa, G.; Zangrando, E.; Chaudhuri,
N. R. Chem. Commun. 2001, 1368.
12 10
H N -
2
2
N, 16.25. IR (KBr): 3515, 3277 (broad), 3117, 3091, 3083, 2263
(νCN), 2198 (νCN), 2187 (νCN), 1612, 1605, 1567, 1501, 1475,
(
(
(
(
18) Falvello, L. R.; Garde, R.; Tom a´ s, M. J. Cluster Sci. 2000, 11, 125.
19) Yuge, H.; Iwamoto, T. J. Chem. Soc., Dalton Trans. 1994, 1237.
20) (a) Munakata, M.; Zhong, J. C.; Ino, I.; Kuroda-Sowa, T.; Maekawa,
M.; Suenaga, Y.; Oiji, N. Inorg. Chim. Acta 2001, 317, 268. (b) Zhan,
S.-z.; Guo, D.; Zhang, X.-y.; Du, C.-x.; Zhu, Y.; Yang, R.-n. Inorg.
Chim. Acta 2000, 298, 57. (c) Mukherjee, P. S.; Maji, T. K.; Mallah,
T.; Zangrando, E.; Randaccio, L.; Chaudhuri, N. R. Inorg. Chim. Acta
1444, 1315, 1254, 1152, 1106, 1037, 777, 731, 650, 531, 430, 415,
-1
405 cm .
X-ray Crystallographic Analysis. Crystallographic data for all
structures are collected in Table 1. All crystals were mounted on
glass fibers using epoxy adhesive. Using the diffractometer control
program DIFRAC22 and an Enraf Nonius CAD4F diffractometer,
data ranges, as indicated in the crystallographic information file
2001, 315, 249.
(21) Kahn, O. Molecular Magnetism; VCH: Weinheim, 1993.
3918 Inorganic Chemistry, Vol. 42, No. 12, 2003

[
Au(CN)
4
]- as a Supramolecular Building Block
Table 1. Summary of Crystallographic Dataa
1
2
3
4
5
formula
fw
space group
a, Å
b, Å
c, Å
C12H18N12Au2NiO
798.98
C12H13N11Au2Cu
768.79
C12H16N12Au2Cu
785.82
C16H24N12Au2Cu
C18H12N10Au2CuO2
857.84
841.95
Pnam (No. 62)
8.9325(12)
15.7920(21)
18.362(4)
90
90
90
2590.1
4
2.159
P 1h (No. 2)
8.372(1)
9.844(1)
14.819(3)
73.00(2)
77.16(2)
68.90(1)
1080.26
2
2.456
144
293
0.022, 0.029
P21/n (No. 14)
7.5489(9)
15.3231(19)
17.7943(19)
90
95.474(8)
90
2048.9(4)
4
2.492
153
293
0.034, 0.033
P21/c (No. 14)
6.688(1)
7.6961(9)
20.273(3)
90
97.044(14)
90
1038.80
2
2.520
151
293
0.030, 0.037
P 1h (No. 2)
7.5006(9)
12.0252(18)
14.2116(17)
73.878(11)
89.642(11)
73.102(11)
1174.39
R, deg
â, deg
γ, deg
3
V, Å
Z
2
3
Fcalc, g/cm
2.426
134
293
0.024, 0.027
-
1
µ, cm
T (K)
121
293
0.035, 0.044
b
R, Rw (I > 2.5σ(I))
a
b
2
-1
Enraf-Nonius CAD-4 diffractometer, Mo KR radiation (λ ) 0.71069 Å), graphite monochromator. Function minimized ∑w(|Fo| - |Fc|) where w
2
2
2
2 1/2
)
σ (Fo) + 0.0001Fo , R ) ∑||Fo| - |Fc||/∑|Fo|, Rw ) (∑w(|Fo| - |Fc|) /∑w|Fo| )
.
(CIF), were recorded. The data were corrected empirically for the
effects of absorption and data reduction for all compounds included
corrections for Lorentz and polarization effects.
For all compounds, coordinates and anisotropic displacement
parameters for the non-hydrogen atoms were refined. The hydrogen
atoms on carbon and nitrogen atoms in all complexes were placed
in calculated positions (d(C-H) 0.95 Å; d(N-H 0.93 Å), and their
coordinate shifts were linked with those of the respective carbon
or nitrogen atoms during refinement. Most of these hydrogen atoms
were observed in Fourier difference maps, in positions that differed
little from the idealized ones ultimately preferred. Isotropic thermal
parameters for these hydrogen atoms were initially assigned
proportionately to the equivalent isotropic thermal parameters of
their respective carbon or nitrogen atoms. Subsequently the isotropic
Figure 1. Molecular structure of Ni(en)2[Au(CN)4]2‚H2O (1). Water and
hydrogen atoms have been omitted for clarity (ORTEP, 50% ellipsoids).
scattering factors for neutral atoms27 were used in the calculation
of structure factors.
Results
thermal parameters for the hydrogen atoms of CH, CH
2 3
, CH , or
Synthesis and Structural Studies. Ni(en)
2 4 2
[Au(CN) ] ‚
NH groups were, respectively, constrained to have identical shifts
2
H
2
O (1). Crystals of 1 formed from an aqueous solution
during refinement. For the water molecule in 1, hydrogen atoms
were positioned geometrically using hydrogen-bonding contacts and
refined with isotropic thermal parameters constrained to be
equivalent. For the water molecules in 5, hydrogen atoms were
found from the Fourier difference map and initially refined against
soft bond distance restraints. However, in the final cycles of
refinement, these hydrogen atoms were constrained to ride on their
respective oxygen atoms and with a single refined isotropic
temperature factor. An extinction parameter23 was included in the
final cycles of full-matrix least-squares refinement of 1-5. The
2+
-
containing [Ni(en)
four νCN bands at 2214, 2202, 2190, and 2180 cm . These
bands, when compared to the νCN band of KAu(CN) at
2
]
4
and 2[Au(CN) ] . The IR data shows
-
1
4
-
1 28
2189 cm , suggest a combination of both transition metal
bound (bridging) and nonbridging cyanides, given that the
IR bands of bridging cyanides shift to higher energy values.13
Similar shifted νCN bands were observed in our previous
-
-1
studies with Au(CN)
2
(νCN band shifts from 2141 cm
-1
-
to between 2143 and 2209 cm ) and Ag(CN)
2
(νCN band
final refinements, using observed data (I
260 parameters for 3655 data; 2 ) 238 parameters for 2148
data; 3 ) 127 parameters for 1472 data; 4 ) 155 parameters for
829 data; and 5 ) 304 parameters for 3015 data. Selected bond
o
g 2.5σ(I
o
)), included 1
-1
-1 3-6
shifts from 2139 cm to between 2140 and 2174 cm ).
)
The X-ray crystal structure of 1 (Figure 1) reveals that the
-
two [Au(CN)
4
] anions are bound in a trans fashion to the
1
octahedral Ni(II) center (Ni(1)-N(11) ) 2.129(5) Å). The
slightly distorted octahedral geometry is completed by two
mutually trans en ligands. Although the asymmetric unit
contains two half-molecules of Ni(en) [Au(CN) ] (each
2 4 2
sitting on a center of inversion), the structural parameters
are essentially identical for both.
lengths and angles for all compounds are found in Tables 2-6.
The programs used for all absorption corrections, data reduc-
tion, and structure solutions of 1-5 were from the NRCVAX
24
Crystal Structure System. The structures were refined using
CRYSTALS.25 Diagrams were made using Ortep-3.26 Complex
One equivalent of water is also found in the unit cell of
the crystal structure. The thermogravimetric analysis data
shows weight loss corresponding to the loss of 1 equiv of
(
(
(
(
22) Gabe, E. J.; White, P. S.; Enright, G. D. DIFRAC A Fortran 77 Control
routine for 4-Circle Diffractometers; NRC: Ottawa, 1995.
23) Larson, A. C. In Crystallographic Computing; Ahmed, F. R., Ed.;
Munksgaard: Copenhagen, 1970; p 291.
24) Gabe, E. J.; LePage, Y.; Charland, J.-P.; Lee, F. L.; White, P. S. J.
Appl. Crystallogr. 1989, 22, 384.
25) Watkin, D. J.; Prout, C. K.; Carruthers, J. R.; Betteridge, P. W.; Cooper,
R. I. CRYSTALS Issue 11.67; Chemical Crystallography Laboratory,
University of Oxford: Oxford, England, 1999.
(27) International Tables for X-ray Crystallography; Kynoch Press: Bir-
mingham, U.K. (present distributor Kluwer Academic Publishers:
Boston, MA), 1975; Vol. IV, p 99.
(28) Sharpe, A. G. The Chemistry of Cyano Complexes of the Transition
Metals; Academic Press: London, 1976.
(26) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
Inorganic Chemistry, Vol. 42, No. 12, 2003 3919

Shorrock et al.
Table 2. Selected Bond Lengths (Å) and Angles (deg) for
Ni(en)2[Au(CN)4]2‚H2O (1)
Au(1)-C(11)
Au(1)-C(13)
Ni(1)-N(11)
Ni(1)-N(5)
1.977(6)
1.985(6)
2.129(5)
2.086(5)
Au(1)-C(12)
Au(1)-C(14)
Ni(1)-N(6)
1.997(6)
1.993(6)
2.099(5)
C(11)-Au(1)-C(13)
N(5)-Ni(1)-N(11)
179.5(2)
88.95(19)
N(5)-Ni(1)-N(6)
N(6)-Ni(1)-N(11)
82.7(2)
89.8(2)
Figure 3. Extended structure of Cu(dien)[Au(CN)4]2 (2) showing the 1-D
network propagated through Au(III)-N interactions. Hydrogen atoms have
been omitted for clarity (ORTEP, 50% ellipsoids).
Table 3. Selected Bond Lengths (Å) and Angles (deg) for
Cu(dien)[Au(CN)4]2 (2)
Au(1)-C(11)
Au(1)-C(13)
Au(2)-C(21)
Au(2)-C(23)
Cu(1)-N(11)
Cu(1)-N(5)
Cu(1)-N(7)
1.995(15)
1.973(16)
1.995(14)
2.025(17)
1.977(12)
1.994(11)
1.984(11)
Au(1)-C(12)
Au(1)-C(14)
Au(2)-C(22)
Au(2)-C(24)
Cu(1)-N(21)
Cu(1)-N(6)
Au(1)-N(22)′
1.988(17)
2.011(19)
1.958(18)
1.953(17)
2.225(13)
1.983(14)
3.002(14)
a
C(11)-Au(1)-C(13) 179.0(6)
C(21)-Au(2)-C(23) 178.7(6)
N(11)-Cu(1)-N(21)
N(11)-Cu(1)-N(6)
N(21)-Cu(1)-N(6)
N(7)-Cu(1)-N(11)
N(5)-Cu(1)-N(7)
99.1(5)
94.6(6)
96.1(5)
167.7(5)
84.0(5)
N(11)-Cu(1)-N(5)
N(21)-Cu(1)-N(5)
N(5)-Cu(1)-N(6)
N(7)-Cu(1)-N(21)
N(6)-Cu(1)-N(7)
93.9(5)
97.7(5)
162.4(6)
93.3(5)
84.3(5)
Cu(1)-N(11)-C(11) 168.2(12) Cu(1)-N(21)-C(21) 166.6(13)
a
1
1
1
Symmetry transformations: (′) x - /2, -y + /2, z - /2.
Figure 4. Extended structure of Cu(en)2[Au(CN)4]2 (3). Hydrogen atoms
have been omitted for clarity (ORTEP, 50% ellipsoids).
1
.977(12) Å) and the other is bound to the elongated apical
site (Cu(1)-N(21) ) 2.225(13) Å). The remaining three
basal sites are occupied by the dien ligand.
Each Cu(dien)[Au(CN)
intermolecular Au(III)-N(cyano) interactions (Au(1)-N(22)′
3.002(14) Å), resulting in a 1-D chain (Figure 3). This is
4 2
] complex is connected by weak
Figure 2. Molecular structure of Cu(dien)[Au(CN)4]2 (2). Hydrogen atoms
have been omitted for clarity (ORTEP, 50% ellipsoids).
)
the first reported Au(III)-N interaction where N interacts
in an apical, intermolecular fashion with a square planar
Au(III), making it weakly 5-coordinate. There are also weak
hydrogen bonds (not shown) between amino hydrogen and
N(cyano) atoms (N(H)-NC distances ) 3.106-3.379 Å).
water between 115 and 185 °C (observed weight loss, 1.80%;
calculated, 2.25%). The complex is then stable until 240 °C,
after which it begins to undergo a complex series of
decompositions yielding NiO and Au at 435 °C (observed
weight loss, 38.5%; calculated, 39.1%). The water molecule
Cu(en)
2 4 2
[Au(CN) ] (3). Crystals of 3 formed from an
2
+
-
serves to weakly connect the Ni(en)
2
[Au(CN)
4
]
2
units into a
aqueous solution containing [Cu(en)
The IR data shows two νCN bands at 2187 and 2180 cm .
The crystal structure indicates that the [Au(CN)
2
]
4
and 2[Au(CN) ] .
-
1
three-dimensional system through hydrogen bonding (O-N
distances: 3.206(8), 2.925(8) Å). There are also additional
hydrogen bonds between many of the amino hydrogen and
N(cyano) atoms (N(H)-NC distances: 3.169-3.323 Å). All
hydrogen bonding is very weak and thus is not shown.
-
4
] ions are
coordinated to the Jahn-Teller distorted axial sites of the
octahedral Cu(II) center (Cu(1)-N(11) ) 2.548(9) Å)
(Figure 4). This axial bond length is significantly longer than
that seen in 1. The axial bond length in 3 is on the weaker
end of the reported distorted Cu(II) complexes in the
Cu(dien)[Au(CN)
aqueous solution containing [Cu(dien)] and 2[Au(CN)
The IR data, showing three νCN bands at 2241, 2219, and
4 2
] (2). Crystals of 2 formed from an
2+
-
4
] .
19,29
literature (which range from 2.2 to 2.7 Å),
thus explaining
-
1
2
189 cm , suggests that there is a combination of bridging
the lack of blue shift of the νCN band in the IR spectrum
for the N-bound cyanide. The equatorial sites of the Cu(II)
are occupied by the two en ligands.
and nonbridging cyanide groups present. The crystal structure
-
confirms that two [Au(CN)
4
] ions are bound to a Cu(II)
center through N(cyano) atoms. The Cu(II) center adopts a
The crystal structure of 3 also displays weak intermolecular
Au(III)-N interactions of 3.035(8) Å. These interactions are
similar to, but slightly weaker than those observed in 2. A
distorted square pyramidal geometry (Figure 2), where one
-
[Au(CN)
4
] unit is bound to the basal site (Cu(1)-N(11) )
3920 Inorganic Chemistry, Vol. 42, No. 12, 2003

[
Au(CN)
4
]- as a Supramolecular Building Block
Table 4. Selected Bond Lengths (Å) and Angles (deg) for
Cu(en)2[Au(CN)4]2 (3)
Au(1)-C(11)
Au(1)-C(13)
Cu(1)-N(11)′
Cu(1)-N(4)
1.995(9)
1.986(9)
2.548(9)
2.015(7)
Au(1)-C(12)
Au(1)-C(14)
Cu(1)-N(3)
1.975(9)
1.990(9)
2.010(7)
3.035(8)
a
Au(1)-N(12)′′
C(11)-Au(1)-C(13)
N(11)′-Cu(1)-N(4)
178.6(3)
88.5(3)
N(11)′-Cu(1)-N(3)
N(3)-Cu(1)-N(4)
93.5(3)
84.3(3)
a
1
Symmetry transformations: (′) x, y - 1, z; (′′) -x + 1, y - /2, -z +
5/
2.
Figure 5. Extended structure of the cation [Cu(dmeda)2Au(CN)4]+ in
Cu(dmeda)2Au(CN)4][Au(CN)4] (4). Hydrogen atoms have been omitted
for clarity (ORTEP, 50% ellipsoids).
[
Table 5. Selected Bond Lengths (Å) and Angles (deg) for
[Cu(dmeda)2Au(CN)4][Au(CN)4] (4)
Au(2)-C(21)
Cu(1)-N(1)
Cu(1)-N(21)′
Au(1)-C(12)
2.007(11)
2.100(8)
2.724(10)
2.001(15)
2.963(13)
Au(2)-C(22)
Cu(1)-N(2)
Au(1)-C(11)
Au(1)-C(13)
1.958(12)
1.985(8)
1.999(10)
2.002(13)
a
Au(1)-N(12)′′
C(12)-Au(1)-C(13)
Au(1)-C(12)-N(12)
N(1)-Cu(1)-N(21)′
175.9(5)
175.1(14)
85.8(3)
C(21)-Au(2)-C(22)
N(1)-Cu(1)-N(2)
N(2)-Cu(1)-N(21)′
89.8(5)
84.6(3)
86.5(3)
a
1
3
1
Symmetry transformations: (′) x - /2, -y + /2, z; (′) -x + /2, -y
/2, z.
+ 1
key difference between 2 and 3 is that, in 3, every
-
[
Au(CN)
4
] unit forms two Au-N interactions by acting as
Figure 6. Extended structure of the [Au(CN)4]- chain in [Cu(dmeda)2Au-
a donor via N(12) for one interaction and an acceptor via
(CN)4][Au(CN)4] (4) (ORTEP, 50% ellipsoids).
Au(1) for another, resulting in a 2-D sheet (Figure 4). This
[Au(CN)4]- ions where two cyanides on [Au(CN) ] are
-
contrasts with the 1-D chain found in 2 (Figure 3) that does
4
-
2+
not propagate in two dimensions because [Au(CN)
4
] units
coordinated to separate [Cu(dmeda)] units in a cis fashion.
only participate in one such interaction, through either the
Au(1) or N(22) atoms.
Despite the weak cyanide ligation, it is chemically sig-
nificant: an immediate precipitation of the insoluble polymer
4 occurs whereas the previous reactions (not producing
cyanometalate-bridged polymeric products) do not im-
mediately precipitate.
The structure of 3 also differs from the analogous Ni(II)
compound 1. The Ni analogue does not display Au(III)-N
interactions, possibly due to steric hindrances, as the
M-N(cyano) bond lengths are significantly shorter in 1.
Hydrogen-bonding interactions involving the water molecule
in 1 may also compete with the weak intermolecular Au-N
interactions.
-
The remaining equivalent of [Au(CN) ] is unbound to
4
any Cu center, but does form Au(III)-N interactions with
-
adjacent free [Au(CN) ] units, generating an anionic 1-D
4
zigzag chain that runs perpendicular to the [Cu(dmeda) -
2
+
Weak hydrogen bonding between amino hydrogen and
N(cyano) atoms is also present in 3 (N(H)-NC distances:
Au(CN) ] chain (Figure 6). The Au(1)-N(12)′′ distance
4
of 2.963(13) is significantly shorter than the Au(III)-N
interactions in 2 and 3.
3
.121(11)-3.395(12) Å).
Cu(dmeda) Au(CN) ][Au(CN)
upon slow evaporation of a very dilute aqueous solution
[
2
4
4
] (4). Crystals of 4 formed
[Cu(bipy)(H O) (Au(CN) ) ][Au(CN) ] (5). Crystals
2
2
4 0.5
4 1.5
of 5 were obtained through slow evaporation of an aqueous/
2
+
-
containing [Cu(dmeda)
at 2190 cm is present. The crystal structure reveals a
distorted octahedral Cu(II) center with two equatorially
2
]
4
and 2[Au(CN) ] . One νCN band
methanolic solution containing 1 equiv of bipy, 2 equiv of
-
1
-
[Au(CN) ] , and an excess of Cu(II). The IR data shows
4
-
1
three νCN bands at 2203, 2198, and 2187 cm , consistent
-
bound dmeda ligands and elongated N(cyano) axial coordi-
with a combination of bridging and nonbridging [Au(CN)4]
-
nation of [Au(CN)
4
] (Figure 5). Although this weak coor-
units. The crystal structure shows a 1-D “criss-crossed” chain
-
dination (Cu(1)′-N(21) ) 2.724(10) Å) does not produce a
blue-shifted νCN band in the IR spectrum, it serves to build
where one [Au(CN) ] unit is bound to four Cu(II) centers
4
-
(Figure 7). Each Cu(II) center has two such [Au(CN) ] units
4
2+
a 1-D cationic zigzag chain of alternating [Cu(dmeda)] and
bound in a cis fashion, resulting in a connectivity to five
other Cu(II) centers and thus 1-D propagation.
(
29) (a) Cˇ ern a´ k, J.; G e´ rard, F.; Chomi cˇ , J. Acta Crystallogr. 1993, C49,
294. (b) Cˇ ern a´ k, J.; Chomi cˇ , J.; Gravereau, P.; Orend a´ cˇ ov a´ , A.;
Orend a´ cˇ , M.; Kov a´ cˇ , J.; Feher, A.; Kappenstein, C. Inorg. Chim. Acta
998, 281, 134. (c) Cˇ ern a´ k, J.; Abboud, K. A.; Chomi cˇ , J.; Meisel,
M. W.; Orend a´ cˇ , M.; Orend a´ cˇ ov a´ , A.; Feher, A. Inorg. Chim. Acta
000, 311, 126. (d) Hathaway, B. J. In ComprehensiVe Coordination
]- units occupy both an equatorial (Cu(1)-
The [Au(CN)
4
1
N(12)′ ) 1.973(6) Å) and an axial site (Cu(1)-N(11) )
.359(6) Å) of the distorted octahedral Cu(II) center. This
1
2
difference in coordinated bond lengths likely results in the
two distinct blue-shifted νCN bands observed in the IR
spectrum. The remaining three equatorial sites on the Cu(II)
center are occupied by the bipy ligand (Cu(1)-N(1) )
2
Chemistry; Wilkinson, G., Gillard, R. D., McCleverty, J. A., Eds.;
Pergamon: Oxford, 1987; Vol. 5, p 533. (e) Kou, H. Z.; Wang, H.-
M.; Liao, D.-Z.; Cheng, P.; Jiang, Z.-H.; Yan, S.-P.; Huang, X.-Y.;
Wang, G.-L. Aust. J. Chem. 1998, 51, 661.
Inorganic Chemistry, Vol. 42, No. 12, 2003 3921

Shorrock et al.
In both cases, [Pt(CN)
4
]2 bridging occurs through only two
-
Table 6. Selected Bond Lengths (Å) and Angles (deg) for
Cu(bipy)(H2O)2(Au(CN)4)0.5][Au(CN)4]1.5 (5)
[
cyanides, rather than four as seen in 5.
Au(1)-C(11)
Au(2)-C(21)
Au(2)-C(23)
Au(3)-C(31)
Cu(1)-N(1)
Cu(1)-N(11)
Cu(1)-O(1)
1.997(7)
1.996(9)
1.985(8)
1.991(9)
1.981(6)
2.359(6)
2.026(5)
Au(1)-C(12)
Au(2)-C(22)
Au(2)-C(24)
Au(3)-C(32)
Cu(1)-N(2)
Cu(1)-N(12)′
Cu(1)-O(2)
1.988(7)
2.019(8)
1.978(8)
2.00(1)
2.001(5)
1.973(6)
2.475(6)
Magnetic Properties. For complexes 3-5 the temperature
T) dependence of the molar magnetic susceptibilities (ø )
M
was measured from 2 to 300 K, and the data were examined
for the presence of magnetic interactions.
(
a
The product of the magnetic susceptibility with temper-
3
ature, ø
M
T, for 3 at 300 K was determined to be 0.48 cm K
C(11)-Au(1)-C(12)
C(31)-Au(3)-C(32)
O(1)-Cu(1)-N(1)
O(1)-Cu(1)-N(2)
N(1)-Cu(1)-N(2)
O(2)-Cu(1)-N(11)
N(2)-Cu(1)-N(11)
O(2)-Cu(1)-N(12)′
N(2)-Cu(1)-N(12)′
91.8(3) C(22)-Au(2)-C(24)
88.4(4) O(1)-Cu(1)-O(2)
95.8(2) O(2)-Cu(1)-N(1)
176.6(2) O(2)-Cu(1)-N(2)
81.6(2) O(1)-Cu(1)-N(11)
174.7(2) N(1)-Cu(1)-N(11)
97.4(2) O(1)-Cu(1)-N(12)′
84.3(2) N(1)-Cu(1)-N(12)′
94.7(2) N(11)-Cu(1)-N(12)′
176.0(3)
91.53(19)
91.5(2)
86.5(2)
84.7(2)
92.6(2)
87.8(2)
174.6(2)
91.7(2)
-
1
1
2
mol , consistent with the presence of an S ) / Cu(II)
2+
center. In 3, the [Cu(dien)] units are essentially isolated
from each other according to the X-ray structure, except for
the presence of intermolecular Au(III)-N interactions. This
pathway is too long for significant magnetic interactions to
occur (and the Cu-N bond is quite long at 2.548(9) Å); thus,
a
as expected, ø
M
T is observed to be virtually temperature
Symmetry transformations: (′) x - 1, y, z.
independent, exhibiting only a very slight decrease (to 0.46
3
-1
cm K mol ) below 25 K.
In both 4 and 5, shorter Cu-Cu interaction pathways are
present. In [Cu(dmeda)
centers are connected through very weakly coordinated
Cu-N ) 2.724(10) Å) axial sites in an orthogonal fashion.
2 4 4
Au(CN) ][Au(CN) ] (4), the Cu(II)
(
For 4, poor overlap associated with this long bond effectively
severs the pathway for magnetic exchange, as previously
3
,5
observed, yielding an essentially temperature independent
ø
0
M
M
T vs T graph until 5 K, at which point ø T drops from
3
-1
.47 to 0.35 cm K mol at 2 K.
3
-1
For 5, ø
M
T ) 0.40 cm K mol at 300 K and is
M
temperature independent until 25 K, at which point ø T drops
3
-1
to 0.29 cm K mol at 2 K. The data can be fit to the Curie-
Weiss law with θ ) -0.40 K, consistent with weak
antiferromagnetic coupling between the Cu(II) centers. The
Figure 7. Extended structure of [Cu(bipy)(H2O)2(Au(CN)4)0.5][Au(CN)4]1.5
5) showing only the 1-D chain of [Cu(bipy)(H2O)2(Au(CN)4)0.5]1.5+
Hydrogen atoms have been omitted for clarity (ORTEP, 50% ellipsoids).
(
.
2 2 4 4 1.5
X-ray structure of [Cu(bipy)(H O) (Au(CN) )0.5][Au(CN) ]
(
5) shows several magnetic exchange pathways between
1
.981(6) Å and Cu(1)-N(2) ) 2.001(5) Å) and a bound
Cu(II) centers that must be considered; each has a through-
bond Cu-Cu distance of approximately 10 Å. Each Cu(II)
center has two linear pathways, one through elongated axial/
axial bonding (Cu-N(11) ) 2.359(6) Å) and one through
equatorial/equatorial bonding (Cu-N(12) ) 1.973(6) Å).
Each Cu(II) center also has four axial/equatorial pathways
water molecule (Cu(1)-O(1) ) 2.026(5) Å), with the final
elongated axial site occupied by the other equivalent of water
(Cu(1)-O(2) ) 2.475(6) Å).
]- form a linear
4
The remaining equivalents of [Au(CN)
trimeric anionic cluster via a Au(III)-N interaction of
.052(9) Å, similar to that seen in 4 and comparable in length
3
(through a combination of Cu-N(11) and Cu-N(12) bonds).
to that seen in 2 and 3. However, unlike in 4, the interaction
does not propagate.
The orthogonal axial/equatorial pathways are known to
generate ferromagnetic coupling, whereas the equatorial/
equatorial and axial/axial pathways generate antiferro-
3
1
Both the coordinated water molecules and the bipy ligands
serve to increase dimensionality through weak hydrogen
bonds and π-interactions, respectively. The structure is thus
loosely held in a three-dimensional array (not shown).
Similar 1-D chains have been observed in a related
3
2
magnetic coupling. The observed weak coupling is likely
a combination of the antiferromagnetic and ferromagnetic
coupling pathways. Of these, the equatorial/equatorial
pathway yields the strongest orbital overlap, as all other
pathways utilize the elongated Cu-N(11) axial bond. Due
to the complexity of possible magnetic pathways and the
overall weak magnetic interaction, this data was not further
analyzed.
2-
[
(
(
Ni(CN)
4
]
complex, [{Cu
2
(medpt)
2
Ni(CN)
4
}(ClO
4
)
2
2
‚2.5H O]
medpt ) bis(3-aminopropyl)methylamine), whereby [Ni-
CN)
2-
4
]
anions coordinate through all four cyanides to form
a “criss-crossed” 1-D chain of connected square pyramidal
Cu(II) cations. The analogous [Pt(CN)
1
7
2-
4
]
complex with
2
+
[Cu(bipy)] does not form such “criss-crossed” chains, but
instead forms either a discrete supramolecular square via cis
(
30) Falvello, L. R.; Tom a´ s, M. Chem. Commun. 1999, 273.
coordination of two cyanometalates in the case of [{Cu-
(31) Vicente, R.; Escuer, A.; Pe n˜ alba, E.; Solans, X.; Font-Bard ´ı a, M. Inorg.
Chim. Acta 1997, 255, 77.
3
0
(
bipy)(H
2
O)Pt(CN)
4
}
2
2
]‚2H O, or an infinite 1-D chain with
(32) White, C. A.; Yap, G. P. A.; Greedan, J. E.; Crutchley, R. J. Inorg.
18
trans cyanide coordination in the case of Cu(bipy)Pt(CN)
4
.
Chem. 1999, 38, 2548.
3922 Inorganic Chemistry, Vol. 42, No. 12, 2003

[
Au(CN)
4
]- as a Supramolecular Building Block
Discussion
elongated apical M-ligand bond lengths are observed, such
as seen in many examples with Cl in the apical position,
where Au-Cl distances range between 2.911(2) and 3.223(3)
Although the use of cyanometalate anions as building
blocks in the formation of coordination polymers has been
well-documented (especially octahedral cyanometalates),
35
Å. A more comparable intermolecular interaction has been
8
,13,14
observed between square planar Au(III) and an oxygen donor
-
the [Au(CN)
4
] unit has never previously been used as such
36
where Au-O ) 3.010(4) Å. When such interactions are
a building block. Systems 4 and 5 are the first examples of
sterically enforced by the presence of a relatively rigid
multidentate ligand, Au-N distances become significantly
shorter, such as observed in many Au-amine complexes
-
[Au(CN)
4
] -based coordination, where polymer formation
is a result of multiple cyanide bridging (2-cis and 4) through
the anionic building block. Similar coordination polymers
have been formed with other related anions, such as
where the Au-N distances range from 2.58(1) to 2.839(5)
37-39
Å.
These examples are considered to be more intra-
2-
2- 13,15-18
-
[Ni(CN)
4
]
and [Pt(CN)
4
] .
4
Also, the [Au(CN) ] -
molecular in nature, as they are assisted by the coordination
of one part of a multidentate ligand to a square planar site
of Au(III). Without further literature examples of Au(III)-N
intermolecular interactions, it becomes difficult to comment
on its strength. The Au-N interaction distances (ranging
from 2.963(13) to 3.052(9) Å) can be compared to the sum
based systems are quite different from previously studied
-
3-5
[
2
Au(CN) ] -based polymers, as would be expected given
the change in oxidation state and geometry (from linear to
square planar).
In general, the formation of cyanometalate-containing
coordination polymers and their dimensionality depend on
the type of capping ligand and number of open coordination
sites that exist on the cation.3-6 This dependence, however,
does not appear to be a strong factor in [Au(CN)
systems. Although 1, 2, and 3 all have either two or three
available coordination sites (hence the possibility for increas-
ing dimensionality via cyanometalate bridging), in all cases
the [Au(CN)
40
of the van der Waals radii (3.12-3.27 Å).
With Cu(II), Jahn-Teller distortion results in very different
coordination polymers as compared to the equivalent Ni(II)
systems. This is evident in comparing the similar complexes
-
4
] -based
M(en)
the [Au(CN)
2
[Au(CN)
4
]
2
(1, M ) Ni; 3, M ) Cu). In both cases,
-
4
] unit is coordinated in a trans fashion, but in
3
the M-N(cyano) distances are significantly longer (2.548(9)
-
4
] unit coordinates through one cyanide only,
Å) as compared to 1 (2.129(5) and 2.116(5) Å). In 3, the
molecular unit is thus significantly longer than in 1, allowing
room for Au(III)-N interactions between molecular units,
which does not occur in 1. Even though 1 has a water
molecule within the unit cell, which could interfere with
potential interactions, a similar comparison can also be made
between 3 and 4, which differ only in two additional methyl
groups on the ligand in 4 and do not contain the complication
of interstitial water. There is a difference in coordination
lengths between the two systems: the axial Cu-N(cyano)
bond length is 2.724(10) Å in 4, compared to 2.548(9) Å in
resulting in molecular systems (excluding Au(III)-N or
hydrogen-bonding interactions). This contrasts with systems
such as [Ni(en)
6,33
2 2 3 2 2 2
Ag (CN) ][Ag(CN) ], [Cu(dien)Ag(CN) ] -
6
3
[
Ag (CN) ][Ag(CN) ], and [Cu(en) Au(CN) ][Au(CN) ], all
2
3
2 2 2 2
of which show similar transition metal coordination spheres,
but show increased dimensionality through bridging cyano-
metalates. This bridging coordination is seen in 4 and 5,
which still each contain two open coordination sites at the
Cu(II) cation, suggesting that there are more important factors
at play. One key factor is likely the decreased basicity of
Au(III) vs both Au(I) cyanometalates and [M(CN)
would decrease the propensity of the cyanometalate to
coordinate to another metal center, and hence decrease the
2
-
4
]
which
3
. This elongation of the molecular unit in 4 may be
-
providing the space required for the [Au(CN)
4
]
unit to
further coordinate another Cu(II) center without steric
hindrances, as 4 is able to form a cyano-bridged polymer,
whereas 3 is not. These observations suggests that the longer
the molecular unit, the stronger the propensity to form
additional bridging interactions.
likelihood of bridging cyanides. Although the square planar
-
[
Au(CN)
4
] has increased steric bulk as compared to a linear
Au(I) cyanometalate, this is likely not causing decreased
bridging, as many [Pt(CN)
polymers have been reported.
2
-
2-
4
]
and [Ni(CN)
4
]
bridging
1
3,15-20
]- unit in 1-5 has been observed to bridge
The [Au(CN)
4
Still, increases in dimensionality through intermolecular
Au(III)-N interactions are observed in [Au(CN)
These are the first reported Au-N interactions whereby a
nitrogen atom interacts at the apical site of a square planar
Au(III) molecule in an intermolecular fashion (i.e., without
the aid of chelation). This interaction serves to increase the
dimensionality of heterobimetallic systems (2 and 3) and also
generates chains of associated [Au(CN)
It is uncommon for Au(III) atoms to display coordination
environments other than square planar, though a few higher
coordination geometries do exist.34 In such cases, very
through one cyanide, two cyanides (cis), or all four cyanides.
-
4
] systems.
(
35) (a) Timkovich, R.; Tulinsky, A. Inorg. Chem. 1977, 16, 962. (b) Elder,
R. C.; Watkins, J. W., II. Inorg. Chem. 1986, 25, 223. (c) Micklitz,
W.; Lippert, B.; M u¨ ller, G.; Mikulcik, P.; Riede, J. Inorg. Chim. Acta
1
989, 165, 57. (d) Sommerer, S. O.; MacBeth, C. E.; Jircitano, A. J.;
Abboud, K. A. Acta Crystallogr. 1997, C53, 1551.
(36) Shimanski, A.; Freisinger, E.; Erxleben, A.; Lippert, B. Inorg. Chim.
Acta 1998, 283, 223.
(
37) (a) Charlton, R. J.; Harris, C. M.; Patil, H.; Stephenson, N. C. Inorg.
Nucl. Chem. Lett. 1966, 2, 409. (b) Robinson, W. T.; Sinn, E. J. Chem.
Soc., Dalton Trans. 1975, 726. (c) O’Connor, C. J.; Sinn, E. Inorg.
Chem. 1978, 17, 2067. (d) Marangoni, G.; Pitteri, B.; Bertolasi, V.;
Gilli, G.; Ferretti, V. J. Chem. Soc., Dalton Trans. 1986, 1941. (e)
Ferretti, V.; Gilli, P.; Bertolasi, V.; Marangoni, G.; Pitteri, B.; Chessa,
G. Acta. Crystallogr. 1992, C48, 814.
-
4
] anions (4 and 5).
(
38) Vicente, J.; Chicote, M. T.; Berm u´ dez, M. D.; Jones, P. G.; Fittschen,
C.; Sheldrick, G. M. J. Chem. Soc., Dalton Trans. 1986, 2361.
(
33) Zhang, H.-X.; Chen, Z.-N.; Su, C.-Y.; Ren, C.; Kang, B.-S. J. Chem.
Crystallogr. 1999, 29, 1239.
(39) Ferretti, V.; Gilli, P.; Bertolasi, V.; Marangoni, G.; Pitteri, B.; Chessa,
G. Acta Crystallogr. 1992, C48, 814.
(34) (a) Jones, P. G. Gold Bull. 1981, 14, 103. (b) Jones, P. G. Gold Bull.
1983, 16, 114.
(40) Bondi, A. J. Phys. Chem. 1964, 68, 441.
Inorganic Chemistry, Vol. 42, No. 12, 2003 3923

Shorrock et al.
Although the steric profile of the ligands may influence the
number of briding cyanides possible, another consideration
is that both the hydrogen bonding and Au(III)-N interactions
may be influencing the formation of cyano bridges to the
metal centers. This interplay of intermolecular (hydrogen
bonding) and intramolecular (cyanide coordination) interac-
tions has been a topic of recent interest. In comparing the
between the Au(III) and Pt(II)/Pd(II) cyano complexes, the
similarities between the aforementioned PtCu Hofmann
clathrate and [(CN)
3 3 4
Pt(µ-CN)Cu(NH ) ] complexes suggest
that competition from intermolecular interactions and cyano
8
bridging might affect stacking, as the clathrate shows no d -
8
d
stacking, whereas the latter complex shows Pt-Pt
4
1,42
interactions of 3.675 Å.
The choice of the ancillary
discrete square complex of [Pt(CN)
to the polymeric 1-D chain of [Pt(CN)
4
Cu(bipy)(H
2
O)]
2
‚2H
2
O
ligands used may also exclude the possibility of stacking
interactions-we are currently examining the effects of
complex cation size and ligand choice and are working to
minimize possible interfering interactions.
4
Cu(bipy)], it has been
suggested that the square complex results from the stabiliza-
tion imparted by hydrogen bonding to the terminal cyanide
moieties such that these stabilizing hydrogen bonds compete
with the cyano coordination and formation of the polymeric
Conclusions
4
1
form. This has similarly been the suggestion for the
The first supramolecular coordination polymers containing
41
-
-
differences between [(CN)
Hofmann clathrate system [Pt(CN)
guest molecule).42 The former complex, which bridges
3
Pt(µ-CN)Cu(NH
3
)
4
]
and the
4 4
[Au(CN) ] have been prepared, indicating that [Au(CN) ]
4
Cu(NH
3 2
) ]
n
‚2nG (G )
may serve as a useful building block in the preparation of
coordination polymers. Through multiple cyanide bridging,
it can increase dimensionality of a molecular unit to a 1-D
2-
through only one cyanide of the [Pt(CN)
four NH ligands and an extensive network of intermolecular
interactions, whereas the latter PtCu Hoffmann clathrate
4
]
unit, contains
3
polymer, and via weak intermolecular Au(III)-N interac-
-
tions, [Au(CN)
4
] can also increase dimensionality up to two
contains only two NH
cyanides.
No d -d stacking interactions were observed in our
systems, despite the fact that [Au(CN)
isostructural to [Pt(CN)
3
ligands and bridges through all four
dimensions.
Acknowledgment. Financial support from NSERC of
Canada and the World Gold Council GROW program are
gratefully acknowledged.
8
8
-
4
] is isoelectronic and
2-
2-
4
]
4
and [Pd(CN) ] . Although this
Supporting Information Available: Complete crystallographic
data in CIF format for all five reported crystal structures.
This material is available free of charge via the Internet at
http://pubs.acs.org.
might suggest that there are significant electronic differences
(
41) Escorihuela, I.; Falvello, L. R.; Tom a´ s, M. Inorg. Chem. 2001, 40,
36.
6
(42) Iwamoto, T.; Nalkano, T.; Morita, M.; Miyoshi, T.; Miyamoto, T.;
Sasaki, Y. Inorg. Chim. Acta 1968, 2-3, 313.
IC0341441
3924 Inorganic Chemistry, Vol. 42, No. 12, 2003