Two [Au(CN)₂]⁻-bridged heterometallic coordination polymers directed by different 2,2′-bipyridyl-like ligands

Abstract

Two new cyanide-bridged heterobimetallic coordination polymers constructed by using the [Au(CN)₂]⁻ building block, {Cd(bipy)[Au(CN)₂]₂}_n (1) and {{Cd(phen)[Au(CN)₂]₂(H₂O)}·iPrOH}_n (2) (bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized. Complex 1 with chiral P3₁12 space group exhibits a novel three-fold interpenetrating quartz-like 3-D network, which is completely unsupported by aurophilic interactions, while complex 2 with the replacement of bipy by phen shows C2/c space group and features the 1-D zigzag chain structure and an extended supramolecular 2-D array in which aurophilic interactions may play an important role in sustaining the supramolecular solid-state architectures. 1 and 2 feature various networks most likely due to the different steric hindrances of the bipy and phen ligands. In addition, the solid state photoluminescence spectrum of complex 2 exhibits a strong green emission band (λ_max = 524 nm) at room temperature.

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Introduction

The construction of coordination polymers built upon molecular building blocks has become an area of intense interest in recent years.¹ This is due not only to their useful optical, conducting or magnetic properties, but also to their porous functions such as catalysis, separation, molecular recognition, ion-exchange, sorption–desorption, etc.^2–5 Among these materials, cyanide-bridged coordination polymers which are prepared from assembling cyanometallate building blocks and transition metal centers, have been shown to exhibit a remarkable diversity of structural types with interesting magnetic, magneto-optical, electrochemical and zeolitic materials properties.⁶

The linear dicyanoaurate anion [Au(CN)₂]⁻ is an ideal building block for the construction of cyanide-bridged coordination polymers. From a material point of view, it can be utilized to construct heterometallic complexes showing interesting magnetic, spin-crossover, vapochromic, birefringent and zeolite-like properties.⁷ On the other hand, the bidentate [Au(CN)₂]⁻group can be served as a 2-connector to establish strong coordinative bonds between the cyanide groups and a second metal cations. Using this 2-connecting unit, some cyanide-bridged extended systems with 1-D,⁸ 2-D^7h,9 and 3-D⁹ polymeric structures have been obtained. Apart from being a μ₂- bridging ligand, [Au(CN)₂]⁻ can also produce supramolecular solid-state architectures through weakly bonding aurophilic interactions which have order-of-magnitude strengths comparable to hydrogen-bonding interactions,¹⁰ and this attractive Au⋯Au interactions can be used as a useful tool to control supramolecular dimensionality.^{7h,8b–8d,11} As a supramolecular element, this aurophilicity can play an important role in producing some fascinating networks with intriguing topologies such as interpenetrating,^{7a–7c,8c,12} microporous,^7a,12f Hoffman-like^13a and interwoven^13b frameworks. In addition, [Au(CN)₂]⁻ salts are known to have luminescent properties¹⁴ and some complexes assembled using these building blocks may retain this useful material property as a result of the aggregates of [Au(CN)₂]⁻ ions.¹¹

In view of the important role of the aromatic chelate 2,2′-bipyridyl-like ligands such as 2,2′-bipyridine (bipy) and 1,10-phenanthroline (phen) in the development of coordination supramolecular networks,¹⁵ we present here the syntheses and characterizations of two novel cyanide-bridged heterometallic coordination polymers incorporating [Au(CN)₂]⁻ building block and 2,2′-bipyridyl-like ligands, {Cd(bipy)[Au(CN)₂]₂}_n (bipy = 2,2′-bipyridine) (1) and {{Cd(phen)[Au(CN)₂]₂(H₂O)}·iPrOH}_n (phen = 1,10-phenanthroline, iPrOH = isopropanol) (2). In the two complexes, using different bipy and phen chelating ligands, [Au(CN)₂]⁻ tecton links cadmium ions in various coordination modes, giving rise to one- or three-dimensional heterobimetallic Cd(II)–Au(I) coordination polymers, respectively.

Experimental

Materials and general methods

The solvents and reagents for synthesis were commercially available and used as received. Elemental analyses (C, H and N) were performed on a Perkin-Elmer 240 analyzer. The FT-IR spectra were measured with a Bruker Tensor 27 spectrometer on KBr pellets in the region of 4000–400 cm⁻¹. Emission spectra in solid state at room temperature were taken on a Cary Eclips fluorescence spectrophotometer.

Caution! The cyanides are very toxic and the perchlorate salts of metal compounds with organic ligands are potentially explosive. Only small amounts of material should be cautiously handled.

Synthesis of complexes 1 and 2

{Cd(bipy)[Au(CN)₂]₂}_n (1). Complex 1 was obtained by a slow diffusion method. One arm of an H-shaped tube contains a mixture of Cd(ClO₄)₂·6H₂O (0.2 mmol) and 2,2′-bipyridine (0.2 mmol) in methanol–water (1 : 2, 6 mL), the other arm contains a water solution (6 mL) of K[Au(CN)₂] (0.4 mmol). The remaining of the vessel was full of isopropanol. Diamond-shaped colorless crystals were obtained after 5 months. Yield: 39% (based on Cd(II) salts). IR (KBr disk): ν_CN 2144, 2155, and 2176 cm⁻¹. Elemental analysis (%) calcd for C₁₄H₈Au₂CdN₆ (1): C 21.93, H 1.05, N 10.96; Found: C 21.82, H 1.10, N 10.88.

{{Cd(phen)[Au(CN)₂]₂(H₂O)}·iPrOH}_n (2). The synthesis procedure of complex 2 is similar to that of 1 except that the organic ligand 1,10-phenanthroline was used instead of 2,2′-bipyridine. Yield: 65% (based on Cd(II) salts). IR (KBr disk): ν_CN 2143, and 2169 cm⁻¹. Elemental analysis (%) calcd for C₁₉H₁₆Au₂CdN₆O₂ (2): C 26.33, H 1.86, N 9.70; Found: C 26.23, H 1.94, N 9.61.

X-Ray data collection and structure determinations

X-Ray single-crystal diffraction data for complexes 1 and 2 were collected on Bruker Smart 1000 CCD diffractometer with Mo Kα radiation (λ = 0.71073 Å). All the structures were solved by direct methods using the SHELXS program of the SHELXTL package and refined by full-matrix least-squares methods with SHELXL.¹⁶ The metal atoms in each complex were located from the E-maps and other non-hydrogen atoms were located in successive difference Fourier syntheses and refined with anisotropic thermal parameters on F². The hydrogen atoms of the ligand were generated theoretically onto the specific atoms and refined isotropically with fixed thermal factors. Crystallographic data and experimental details for structural analyses are summarized in Table 1. Selected bond lengths and angles are listed in Tables 2 and 3, respectively.

Table 1 Crystallographic data and structure refinement summary for complexes 1 and 2

	1	2
Empirical formula	C14H8Au2CdN6	C19H18Au2CdN6O2
Formula weight	766.60	868.73
Temperature/K	294(2)	294(2)
Crystal system	Hexagonal	Monoclinic
Space group	P3112	C2/c
a/Å	8.9349(19)	18.991(4)
b/Å	8.9349(19)	9.987(2)
c/Å	19.992(4)	24.707(5)
α/°	90	90
β/°	90	100.697(3)
γ/°	120	90
V/Å^3	1382.2(5)	4604.8(16)
Z	3	8
D/g cm^−3	2.763	2.500
μ/mm^−1	17.030	13.654
F(000)	1020	3152
Reflections collected	7751	10815
Unique reflections	1901	4002
Data/restraints/parameters	1901/0/106	4002/32/274
R(int)	0.0709	0.0742
GOF	0.968	1.030
R 1 [I >2σ(I)]	0.0346	0.0636
wR2 [I >2σ(I)]	0.0589	0.1530

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Table 2 Selected bond distances (Å) and angles (°) for complex 1^a

a Symmetry codes: #2 −y + 1, −x + 1, −z + 5/3.
Cd(1)–N(1)	2.346(9)
Cd(1)–N(2)	2.303(9)
Cd(1)–N(3)	2.327(7)
N(1)–Cd(1)–N(1)#2	175.2(5)
N(2)–Cd(1)–N(1)	87.6(3)
N(2)–Cd(1)–N(1)#2	89.4(3)
N(2)–Cd(1)–N(2)#2	103.2(5)
N(2)–Cd(1)–N(3)	94.3(3)
N(2)–Cd(1)–N(3)#2	160.5(3)
N(2)#2–Cd(1)–N(1)	89.4(3)
N(2)#2–Cd(1)–N(1)#2	87.6(3)
N(2)#2–Cd(1)–N(3)	160.4(3)
N(2)#2–Cd(1)–N(3)#2	94.3(3)
N(3)–Cd(1)–N(1)	100.0(3)
N(3)–Cd(1)–N(1)#2	84.0(3)
N(3)–Cd(1)–N(3)#2	69.9(4)
N(3)#2–Cd(1)–N(1)	84.0(3)
N(3)#2–Cd(1)–N(1)#2	100.0(3)

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Table 3 Selected bond distances (Å) and angles (°) for complex 2

Cd(1)–N(1)	2.344(15)
Cd(1)–N(3)	2.245(18)
Cd(1)–N(5)	2.366(14)
Cd(1)–N(2)	2.351(15)
Cd(1)–O(1)	2.283(14)
Cd(1)–N(6)	2.304(14)
N(1)–Cd(1)–N(2)	172.7(5)
N(1)–Cd(1)–N(5)	84.7(5)
N(2)–Cd(1)–N(5)	92.7(5)
N(3)–Cd(1)–N(1)	90.5(6)
N(3)–Cd(1)–N(2)	93.6(6)
N(3)–Cd(1)–N(5)	164.9(6)
N(3)–Cd(1)–N(6)	95.0(6)
N(6)–Cd(1)–N(1)	94.2(5)
N(6)–Cd(1)–N(2)	91.4(5)
N(6)–Cd(1)–N(5)	71.1(6)
N(3)–Cd(1)–O(1)	94.6(7)
O(1)–Cd(1)–N(1)	87.3(6)
O(1)–Cd(1)–N(2)	86.4(5)
O(1)–Cd(1)–N(5)	99.5(7)
O(1)–Cd(1)–N(6)	170.2(7)

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Full crystallographic data for 1 and 2 have been deposited with the CCDC (291090 and 290064, respectively.)

Results and discussion

Description of crystal structures

{Cd(bipy)[Au(CN)₂]₂}_n (1). Single-crystal X-ray analysis reveals that complex 1 shows a novel three-fold interpenetrating quartz-like framework with chiral P3₁12 space group. In the crystal structure, each Cd(II) center is six-coordinated, with a slightly distorted octahedron geometry, by means of four nitrile nitrogen atoms from four bridging [Au(CN)₂]⁻ ligands and two nitrogen atoms from one bipy bidentate chelating ligand (Fig. 1a). The Cd atom lies in a site with the crystallographically imposed twofold and the bipy ligand also lies about a twofold axis. The Cd–N(CN⁻) bond lengths range from 2.303(9) to 2.346(9) Å, and the Cd–N(bipy) bond lengths are 2.327(7) Å. As expected, the [Au(CN)₂]⁻ anions act as μ₂- ligands and are almost linear (C–Au–C = 177.8(5)°). The bond lengths and bond angles of 1 are similar to that found for the related [Au(CN)₂]⁻-Cd(II) compounds.¹⁷ Each cadmium atom is connected to four others by four μ₂-[Au(CN)₂]⁻groups resulting in four-connected 3D networks {Cd[Au(CN)₂]₂}. In this complex, the shortest Au⋯Au distance is about 4.086 Å, which is larger than the sum of the van der Waals radii for gold (3.60 Å) and this suggests that there are no aurophilic interactions in the solid state.^10a,18 From a topological point of view, each Cd(II) centre may be considered as a 4-connecting node with [Au(CN)₂]⁻ fragments acting as linear connecting rods to equivalent nodes. The resulting 3-D framework in 1 has the topology of a quartz-like net with 6⁴8² (6⁴8²-b) vertex symbol.¹⁹ A schematic of the quartz-like nets in 1 is shown in Fig. 1b. The characteristic features of this net include 3-fold axes parallel to the c-axis. Double 6-fold helices are also apparent in the structure, and are also parallel to the c-axis (Fig. 1b). Three identical quartz-like nets are interpenetrating (Fig. 1c) with the interpenetration vectors of [0 1 0], [1 0 0], [1 1 0]. Each pseudo-hexagonal channel in 1 is filled by the bipy ligands and has not shown porosity (ESI, Fig. S1).†

Fig. 1 (a) View of the coordination environment of Cd atom in 1 (some equivalent atoms have been generated to complete the Ni coordination, H atom omitted). (b) Perspective view of the quartz-like network of 1 along the c axis. (c) View of the three-fold interpenetrating networks of 1 along the c axis.

{{Cd(phen)[Au(CN)₂]₂(H₂O)}·iPrOH}_n (2). Single-crystal X-ray analysis reveals that complex 2 consists of [Au(CN)₂]⁻-bridged 1-D chain and shows a 2-D supramolecular array under the intermolecular interactions. In the crystal structure, each Cd(II) center adopts a distorted octahedron geometry and bonds to two nitrogen atoms of one phen ligand, three nitrile nitrogen atoms from three [Au(CN)₂]⁻ anions, and one oxygen atom of one coordinated H₂O molecule (Fig. 2a). There are two kinds of coordination modes within the three [Au(CN)₂]⁻ tectons, two bridging [Au(CN)₂]⁻ ligands and one terminal [Au(CN)₂]⁻ ligand. Each Cd(II) atom is connected to two others by the two μ₂-[Au(CN)₂]⁻ bridges which lead to a 1-D single zigzag chain. From a supramolecular viewpoint, every two single chains form an uncommon aurophilicity-induced 1-D ladder (double zigzag) chain via aurophilic interactions with adjacent Au1⋯Au2 distances of 3.190 Å (Fig. 2b).¹⁸ The ladder chains link each other through a second kind of aurophilic interactions with adjacent Au2⋯Au2 distances of 3.415 Å, creating a 2-D layer structure (Fig. 2c). Here the Au(I) centers of the dicyanoaurate anions assemble in a tetrameric fashion and the zigzag tetramer is comprised of two pairs of interacting dimers. It is worth noting that the heterometallic systems exhibiting aurophilicity-generated gold(I) tetramer motifs are less common.^8c,8e At the same time the face-to-face distance of the two parallel pyridine rings (including N6 atoms) of the phen ligand is calculated to be 3.631 Å with a centroid-to-centroid distance of 3.955 Å, indicating the existence of weaker aromatic π–π stacking interactions between the adjacent chains within the 2D layer.²⁰ In addition, the uncoordinated isopropanol molecules are located in the vicinity of the ladder plane as guest molecules. Two kinds of hydrogen-bonding interactions (O–H⋯O and O–H⋯N) occur in 2 with the distances of O2⋯O1 and O2⋯N4 about 3.224 Å and 2.789 Å, respectively (ESI, Fig. S2, Table S1).† Incorporating coordinative linkage, aurophilic, π–π stacking and hydrogen-bonding interactions results in an 2-D supramolecular array in which aurophilicity may play an important role.^8b–8d

Fig. 2 (a) Perspective views of the coordination environments of Cd atoms in 2 (some equivalent atoms have been generated to complete the Zn coordination, H atoms and iPrOH molecule omitted). (b) Perspective view of the aurophilicity-induced 1-D ladder chain of 2. (c) View of 2-D layer structure constructed from aurophilic interactions with a “tetramer” type of 2 with Au atoms represented by gold spheres and aurophilic interactions represented by gold dotted lines.

Discussion of crystal structures

The quartz-like network occupies a special position within crystal engineering. Few examples of coordination polymers with quartz topology have been reported.^12c,21,22 The present net is a second member of rare three-fold interpenetrating coordination compounds with a quartz-like topology.^21c Interestingly, one of the best known examples is {Zn[Au(CN)₂]₂}_n reported by Robson and co-workers which is six interpenetrating quartz-like and contains exactly the same tecton ([Au(CN)₂]⁻) as 1.^12c The two structures are both interpenetrating quartz-like networks. Besides the different metal ions, there is one significant alteration with the interpenetrating type. The reason why the two structures are much different is not fully understood. Significant Au⋯Au interactions between nets may play a role in the quartz topology of {Zn[Au(CN)₂]₂}_n.^22a The auxiliary bipy ligand may act as part of the frameworks in addition to the effect of the Cd(II) ions in 1 considering that there are no Au⋯Au interactions. For the interpenetrated networks in 1, each independent net is constructed of metal–ligand coordinate bonds, and there is no other intermolecular (aurophilic, hydrogen-bonding, π–π stacking, etc.) interaction between the interpenetrating nets. So the interpenetrating networks are completely unsupported and this system can be regarded as interaction-unsupported interpenetration. Leznoff et al. have pointed out in previous reports that the coordination polymers involving the [Au(CN)₂]⁻ unit have a propensity to display aurophilicity-supported interpenetration.^8c,12a–12e The interaction-unsupported interpenetration type of 1 represents a novel example in the family of [Au(CN)₂]⁻-based interpenetrating networks. Some [N(CN)₂]⁻-based interpenetrating networks have been reported and they are not supported by metal–metal (metallophilic) interactions.²³ For the related [Ag(CN)₂]⁻-bridged polymeric systems, some interpenetrating networks are supported by Ag⋯Ag (argentophilic) interactions,^7a,24 and some are not.²⁵

Although both complexes were prepared from Cd²⁺ ions, [Au(CN)₂]⁻ ligand, H₂O/iPrOH solvents and the same synthesis procedure, the crystal structures are quite different. The size of the terminal ligands can play an important role in coordination environments though 1 and 2 have the same metal-to-ligand ratio.²⁶ The reason why 2 does not show a similar structure to 1 may be the larger steric hindrance of the phen ligand than that of the bipy.

Luminescent property of complex 2

The photoluminescent (PL) property of complex 2 has been investigated in the solid state. Complex 2 exhibits intensive green emission with peak maximum around 524 nm when irradiated with UV radiation (403 nm) at room temperature (Fig. 3). Solid K[Au(CN)₂] had one emission band at 390 nm.^14,27 The free phen·H₂O also fluoresces in the solid state and the emission bands for it are at 365 and 388 nm (λ_ex = 310 nm).^28a Compound [Cd(phen)(NO₃)₂] is usually located at about 400 nm which is assigned to the intraligand fluorescence of coordinated phen ligands.^28b The significant red-shift in 2 may be due to the aurophilic bonding interactions (originated from the close proximity of the [Au(CN)₂]⁻ ions),^14,27 considering the chelation effect of the phen ligand to the metal ion^28c and modification effect of the metal–metal interactions of d¹⁰ system to photoluminescent behavior.^17a,27 The luminescence of aggregates of [Au(CN)₂]⁻ ions has attracted considerable research and, up to date, there are many studies on M^I[Au(CN)₂] (M = K, Cs, Tl),¹⁴Au(I)-Au(I) and Ln(III)–Au(I) (Ln are lanthanides) emission systems,^29,30 but there are very limited reports on M(II)–Au(I) (M²⁺ are close-shell d¹⁰ metal ions or pseudo-closed-shell d⁸ metal ions) emission systems.^17a,27 The incorporation of a preformed luminescent [Au(CN)₂]⁻ precursor into the desired structures may be an effective method for luminescent systems and complex 2 has provided a new material for them.

Fig. 3 Emission spectra of 2 in the solid state at room temperature excited at 403 nm. (Ex = excitation, Em = emission).

Conclusion

In this paper, two novel [Au(CN)₂]⁻-bridged heterometallic coordination polymers with unusual network topologies have been obtained by combining the [Au(CN)₂]⁻ building block with 2,2′-bipyridyl-like ligands. The luminescent property of complex 2 has also been studied. Complex 1 possesses a novel three-fold interpenetrating quartz-like network in which the triple interpenetrating networks are completely unsupported. To the best of our knowledge, 1 represents the second example of three-fold interpenetrating coordination polymer with quartz topology. Complex 2 features the 1-D zigzag chain structure and a further extended 2-D supramolecular array in which aurophilic interactions may play an important role. It is possible that the larger steric hindrance of the phen ligand than that of the bipy plays a key role in the construction of 1 and 2. The solid state sample of 2 exhibits a strong green emission at room temperature which may be the result of aurophilic interactions. The unusual structures of the two compounds incorporating [Au(CN)₂]⁻ building block imply that this building block has a great potential for constructing novel coordination polymers and heterometallic complexes. Meanwhile, different 2,2′-bipyridyl-like ligands such as bipy and phen can modulate the frameworks of the coordination polymers. Incorporating [Au(CN)₂]⁻ into the structure is a useful route to luminescent material and the [Au(CN)₂]⁻-based complexes can provide an impetus for further exploration of various applications of this useful system.

Acknowledgements

This work was financially supported by the National Natural Science Foundation of China (No. 20631030, 20601014) and National Basic Research Program of China (973 Program, 2007CB815305).

References

1. (a) A. J. Blake, N. R. Champness, P. Hubberstey, W. S. Li, M. A. Withersby and M. Schröder, Coord. Chem. Rev., 1999, 183, 117; (b) R. Robson, J. Chem. Soc., Dalton Trans., 2000, 3735; (c) M. Eddaoudi, D. B. Moler, H. Li, B. Chen, T. M. Reineke, M. O'Keeffe and O. M. Yaghi, Acc. Chem. Res., 2001, 34, 319; (d) M. J. Zaworotko, Chem. Commun., 2001, 1; (e) O. M. Yaghi, M. O'Keeffe, N. W. Ockwig, H. K. Chae, M. Eddaoudi and J. Kim, Nature, 2003, 423, 705; (f) L. Brammer, Chem. Soc. Rev., 2004, 33, 476.
2. (a) S. R. Batten, Curr. Opin. Solid State Mater. Sci., 2001, 5, 107; (b) S. L. James, Chem. Soc. Rev., 2003, 32, 276; (c) C. Janiak, Dalton Trans., 2003, 2781.
3. (a) E. Coronado, J. R. Galán-Mascarós, C. J. Gómez-García and V. Laukhin, Nature, 2000, 408, 447; (b) O. R. Evans and W. B. Lin, Acc. Chem. Res., 2002, 35, 511; (c) T. P. Radhakrishnan, Acc. Chem. Res., 2008, 41, 367.
4. (a) D. Maspoch, D. Ruiz-Molina and J. Veciana, J. Mater. Chem., 2004, 14, 2713; (b) C. J. Kepert, Chem. Commun., 2006, 695.
5. (a) O. M. Yaghi, H. Li, C. Davis, D. Richardson and T. L. Groy, Acc. Chem. Res., 1998, 31, 474; (b) P. H. Dinolfo and J. T. Hupp, Chem. Mater., 2001, 13, 3113; (c) C. N. R. Rao, S. Natarajan and R. Vaidhyanathan, Angew. Chem., Int. Ed., 2004, 43, 1466; (d) S. Kitagawa, R. Kitaura and S.-I. Noro, Angew. Chem., Int. Ed., 2004, 43, 2334; (e) J. L. C. Rowsell and O. M. Yaghi, Angew. Chem., Int. Ed., 2005, 44, 4670.
6. (a) K. R. Dunbar and R. A. Heintz, Prog. Inorg. Chem., 1997, 45, 283; (b) M. Verdaguer, A. Bleuzen, V. Marvaud, J. Vaissermann, M. Seuleiman, C. Desplanches, A. Scuiller, C. Train, R. Garde, G. Gelly, C. Lomenech, I. Rosenman, P. Veillet, C. Cartier and F. Villain, Coord. Chem. Rev., 1999, 190, 1023; (c) M. Ohba and H. Okawa, Coord. Chem. Rev., 2000, 198, 313; (d) J. S. Miller and J. L. Manson, Acc. Chem. Res., 2001, 34, 563; (e) J. Černák, M. Orendáč, I. Potočňák, J. Chomič, A. Orendáčová, J. Skoršepa and A. Feher, Coord. Chem. Rev., 2002, 224, 51; (f) O. Sato, T. Iyoda, A. Fujishima and K. Hashimoto, Science, 1996, 272, 704.
7. (a) V. Niel, A. L. Thompson, M. C. Muñoz, A. Galet, A. E. Goeta and J. A. Real, Angew. Chem., Int. Ed., 2003, 42, 3760; (b) A. Galet, M. C. Muñoz, V. Martínez and J. A. Real, Chem. Commun., 2004, 2268; (c) A. Galet, M. C. Muñoz and J. A. Real, Chem. Commun., 2006, 4321; (d) J. Lefebvre, R. J. Batchelor and D. B. Leznoff, J. Am. Chem. Soc., 2004, 126, 16117; (e) J. Lefebvre, F. Callaghan, M. J. Katz, J. E. Sonier and abd D. B. Leznoff, Chem.–Eur. J., 2006, 12, 6748; (f) M. J. Katz, P. M. Aguiar, R. J. Batchelor, A. A. Bokov, Z.-G. Ye, S. Kroeker and D. B. Leznoff, J. Am. Chem. Soc., 2006, 128, 3669; (g) M. J. Katz, H. Kaluarachchi, R. J. Batchelor, A. A. Bokov, Z.-G. Ye and D. B. Leznoff, Angew. Chem., Int. Ed., 2007, 46, 8804; (h) E. Colacio, F. Loret, R. Kivekäs, J. Ruiz, J. Suárez-Varela and M. R. Sundberg, Chem. Commun., 2002, 592.
8. (a) I. K. Chu, I. P. Y. Shek, K. W. M. Siu, W.-T. Wong, J.-L. Zuo and T.-C. Lau, New J. Chem., 2000, 24, 765; (b) D. B. Leznoff, B.-Y. Xue, B. O. Patrick, V. Sanchez and R. C. Thompson, Chem. Commun., 2001, 259; (c) D. B. Leznoff, B.-Y. Xue, R. J. Batchelor, F. W. B. Einstein and B. O. Patrick, Inorg. Chem., 2001, 40, 6026; (d) E. Colacio, F. Loret, R. Kivekäs, J. Ruiz, J. Suárez-Varela, M. R. Sundberg and R. Uggla, Inorg. Chem., 2003, 42, 560; (e) G.-F. Xu, Z.-Q. Liu, H.-B. Zhou, Y. Guo and D.-Z. Liao, Aust. J. Chem., 2006, 59, 640; (f) A. R. Geisheimer, M. J. Katz, R. J. Batchelor and D. B. Leznoff, CrystEngComm, 2007, 9, 1078.
9. J. Lefebvre, D. Chartrand and D. B. Leznoff, Polyhedron, 2007, 26, 2189.
10. (a) H. Schmidbaur, Chem. Soc. Rev., 1995, 24, 391; (b) P. Pyykkö, Chem. Rev., 1997, 97, 597; (c) H. Schmidbaur, Gold Bull., 2000, 33, 3; (d) R. J. Puddephatt, Coord. Chem. Rev., 2001, 216, 313; (e) P. Pyykkö, Angew. Chem., Int. Ed., 2004, 43, 4412.
11. D. B. Leznoff and J. Lefebvre, Gold Bull., 2005, 38, 47.
12. (a) S. C. Abrahams, J. L. Bernstein, R. Liminga and E. T. Eisenmann, J. Chem. Phys., 1980, 73, 4585; (b) S. C. Abrahams, L. E. Zyontz and J. L. Bernstein, J. Chem. Phys., 1982, 76, 5458; (c) B. F. Hoskins, R. Robson and N. V. Y. Scarlett, Angew. Chem., Int. Ed. Engl., 1995, 34, 1203; (d) W.-F. Yeung, W.-T. Wong, J.-L. Zuo and T.-C. Lau, J. Chem. Soc., Dalton Trans., 2000, 629; (e) D. B. Leznoff, B.-Y. Xue, C. L. Stevens, A. Storr, R. C. Thompson and B. O. Patrick, Polyhedron, 2001, 20, 1247; (f) W. Dong, L.-N. Zhu, Y.-Q. Sun, M. Liang, Z.-Q. Liu, D.-Z. Liao, Z.-H. Jiang, S.-P. Yan and P. Cheng, Chem. Commun., 2003, 2544; (g) C. Paraschiv, M. Andruh, S. Ferlay, M. Wais Hosseini, N. Kyritsakas, J.-M. Planeix and N. Stanica, Dalton Trans., 2005, 1195.
13. (a) J. Suárez-Varela, H. Sakiyama, J. Cano and E. Colacio, Dalton Trans., 2007, 249; (b) Y.-H. Feng, Y. Guo, Y. OuYang, Z.-Q. Liu, D.-Z. Liao, P. Cheng, S.-P. Yan and Z.-H. Jiang, Chem. Commun., 2007, 3643.
14. (a) N. Nagasundaram, G. Roper, J. Biscoe, J. W. Chai, H. H. Patterson, N. Blom and A. Ludi, Inorg. Chem., 1986, 25, 2947; (b) Z. Assefa, F. DeStefano, M. A. Garepapaghi, J. H. LaCasce, Jr., S. Ouellete, M. R. Corson, J. K. Nagle and H. H. Patterson, Inorg. Chem., 1991, 30, 2868; (c) M. A. Rawashdeh-Omary, M. A. Omary and H. H. Patterson, J. Am. Chem. Soc., 2000, 122, 10371; (d) M. A. Rawashdeh-Omary, M. A. Omary, H. H. Patterson and J. P. Jr. Fackler, J. Am. Chem. Soc., 2001, 123, 11237.
15. B.-H. Ye, M.-L. Tong and X.-M. Chen, Coord. Chem. Rev., 2005, 249, 545.
16. G. M. Sheldrick, SHELXTL NT Version 5.1. Program for Solution and Refinement of Crystal Structures, University of Göttingen, Germany, 1997.
17. (a) H. Zhang, J.-W. Cai, X.-L. Feng, T. Li, X.-Y. Li and L.-N. Ji, Inorg. Chem. Commun., 2002, 5, 637; (b) S.-P. Wang, D.-Z. Gao, Z.-Q. Liu, Z.-H. Jiang, S.-P. Yan and D.-Z. Liao, J. Coord. Chem., 2007, 60, 1599.
18. (a) S. S. Pathaneni and G. R. Desiraju, J. Chem. Soc., Dalton Trans., 1993, 319; (b) P. Pyykkö and N. Runeberg, Chem. Phys. Lett., 1994, 218, 133; (c) M. Bardají and A. Laguna, J. Chem. Educ., 1999, 76, 201.
19. (a) A. F. Wells, Three Dimensional Nets and Polyhedra, Wiley-Interscience, New York, 1977; (b) Further Studies of Three-dimensional Nets, ACA Monograph No. 8, American Crystallographic Association, 1979; (c) O. V. Dolomanov, A. J. Blake, N. R. Champness and M. Schröder, J. Appl. Crystallogr., 2003, 36, 1283.
20. C. Janiak, J. Chem. Soc., Dalton Trans., 2000, 3885.
21. (a) J. Sun, L. Weng, Y. Zhou, J. Chen, Z. Chen, Z. Liu and D. Zhao, Angew. Chem., Int. Ed., 2002, 41, 4471; (b) E. Tynan, P. Jensen, N. R. Kelly, P. E. Kruger, A. C. Lees, B. Moubaraki and K. S. Murray, Dalton Trans., 2004, 3440; (c) S. Hu and M.-L. Tong, Dalton Trans., 2005, 1165; (d) Z.-F. Chen, S.-F. Zhang, H.-S. Luo, B. F. Abrahams and H. Liang, CrystEngComm, 2007, 9, 27; (e) T.-T. Luo, Y.-H. Liu, C.-C. Chan, S.-M. Huang, B.-C. Chang, Y.-L. Lu, G.-H. Lee, S.-M. Peng, J.-C. Wang and K.-L. Lu, Inorg. Chem., 2007, 46, 10044; (f) Q. Zhang, Z. Lin, X. Bu, T. Wu and P. Feng, Chem. Mater., 2008, 20, 3239.
22. (a) Reviews, S. R. Batten and R. Robson, Angew. Chem., Int. Ed., 1998, 37, 1460; (b) S. R. Batten, CrystEngComm, 2001, 3, 67; (c) L. Carlucci, G. Ciani and D. M. Proserpio, Coord. Chem. Rev., 2003, 246, 247.
23. (a) For example, J. L. Manson, C. D. Incarvito, A. L. Rheingold and J. S. Miller, J. Chem. Soc., Dalton Trans., 1998, 3705; (b) S. R. Batten, A. R. Harris, P. Jensen, K. S. Murray and A. Ziebell, J. Chem. Soc., Dalton Trans., 2000, 3829; (c) B.-W. Sun, S. Gao, B.-Q. Ma and Z.-M. Wang, New J. Chem., 2000, 24, 953; (d) E.-Q. Gao, S.-Q. Bai, Z.-M. Wang and C.-H. Yan, Dalton Trans., 2003, 1759; (e) A. M. Kutasi, A. R. Harris, S. R. Batten, B. Moubaraki and K. S. Murray, Cryst. Growth Des., 2004, 4, 605; (f) T. K. Maji, R. Matsuda and S. Kitagawa, Nat. Mater., 2007, 6, 142.
24. (a) For example, C. J. Shorrock, B.-Y. Xue, P. B. Kim, R. J. Batchelor, B. O. Patrick and D. B. Leznoff, Inorg. Chem., 2002, 41, 6743; (b) A. Galet, V. Niel, M. C. Muñoz and J. A. Real, J. Am. Chem. Soc., 2003, 125, 14224; (c) A. Galet, M. C. Muñoz, A. B. Gaspar and J. A. Real, Inorg. Chem., 2005, 44, 8749.
25. (a) For example, T. Soma, H. Yuge and T. Iwamoto, Angew. Chem., Int. Ed. Engl., 1994, 33, 1665; (b) W. Dong, Q.-L. Wang, S.-F. Si, D.-Z. Liao, Z.-H. Jiang, S.-P. Yan and P. Cheng, Inorg. Chem. Commun., 2003, 6, 873.
26. A.-L. Cheng, Y. Ma, J.-Y. Zhang and E.-Q. Gao, Dalton Trans., 2008, 1993.
27. (a) J.-X. Chen, W.-H. Zhang, X.-Y. Tang, Z.-G. Ren, H.-X. Li, Y. Zhang and J.-P. Lang, Inorg. Chem., 2006, 45, 7671; (b) M. Stender, R. L. White-Morris, M. M. Olmstead and A. L. Balch, Inorg. Chem., 2003, 42, 4504; (c) C. N. Pettijohn, E. B. Jochnowitz, B. Chuong, J. K. Nagle and A. Vogler, Coord. Chem. Rev., 1998, 171, 85.
28. (a) X. Shi, G. S. Zhu, Q. R. Fang, G. Wu, G. Tian, R. W. Wang, D. L. Zhang, M. Xue and S. L. Qiu, Eur. J. Inorg. Chem., 2004, 185; (b) J.-Y. Wu, C.-H. Chang, T.-W. Tseng and K.-L. Lu, J. Mol. Struct., 2006, 796, 69; (c) A. Thirumurugan, M. B. Avinash and C. N. R. Rao, Dalton Trans., 2006, 221.
29. (a) For example, W.-F. Fu, K.-C. Chan, V. M. Miskowski and C.-M. Che, Angew. Chem., Int. Ed., 1999, 38, 2783; (b) M.-C. Brandys and R. J. Puddephatt, J. Am. Chem. Soc., 2001, 123, 4839; (c) Z. Assefa, M. A. Omary, B. G. McBurnett, A. A. Mohamed, H. H. Patterson, R. J. Staples and J. P. Fackler, Jr., Inorg. Chem., 2002, 41, 6274.
30. (a) For example, Z. Assefa, G. Shankle, H. H. Patterson and R. Reynolds, Inorg. Chem., 1994, 33, 2187; (b) Z. Assefa and H. H. Patterson, Inorg. Chem., 1994, 33, 6194; (c) M. A. Rawashdeh-Omary, C. L. Larochelle and H. H. Patterson, Inorg. Chem., 2000, 39, 4527; (d) J. C. F. Colis, C. Larochelle, R. Staples, R. Herbst-Irmerd and H. H. Patterson, Dalton Trans., 2005, 675.

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Footnote

† Electronic supplementary information (ESI) available: Perspective view of the pseudo-hexagonal channel in 1 (a) and of the phen ligands in the network of 1 (b) along the c axis (Fig. S1); view of the supramolecular structure of 2 showing Au⋯Au and two kinds of hydrogen bonds (Fig. S2); distances and angles of hydrogen bonds for complex 2 (Table S1); . CCDC reference numbers 290064 and 291090. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/b809381d

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