Bis{1,4-bis­[(3-butyl­imidazolium-1-yl)meth­yl]benzene}­silver(I) bis­(hexa­fluoridophosphate)

Rosenani A Haque; Abbas Washeel; Siang Guan Teoh; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536810036524

. 2010 Sep 25;66(Pt 10):m1286–m1287. doi: 10.1107/S1600536810036524

Bis{1,4-bis[(3-butylimidazolium-1-yl)methyl]benzene}silver(I) bis(hexafluoridophosphate)

Rosenani A Haque ^a, Abbas Washeel ^a, Siang Guan Teoh ^a, Madhukar Hemamalini ^b, Hoong-Kun Fun ^b,^*,^‡

PMCID: PMC2983204 PMID: 21587429

Abstract

The asymmetric unit of the title complex, [Ag₂(C₂₂H₃₀N₄)₂](PF₆)₂, consists of one Ag^I ion, one 1,4-bis[(3-butylimidazolium-1-yl)methyl]benzene ligand and one discrete hexafluoridophosphate anion. The formula unit is generated by an inversion center. The unique Ag^I ion is coordinated by two C atoms of two heterocyclic carbene ligands in an essentially linear geometry. In the crystal structure, cations and anions are linked through weak C—H⋯F hydrogen bonds, forming a three-dimensional network.

Related literature

For applications of N-heterocyclic carbenes, see: Tryg et al. (2005 ▶); Herrmann (2002 ▶); Herrmann et al. (1998 ▶); McGuinness et al. (1999 ▶); Tominaga et al. (2004 ▶); Magill et al. (2001 ▶); Yongbo et al. (2008 ▶); Garrison & Youngs (2005 ▶); Kascatan-Nebioglu et al. (2007 ▶); Özdemir et al. (2010 ▶); Medvetz et al. (2008 ▶); Catalano & Malwitz (2003 ▶). For a related structure, see: Chen & Liu (2003 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer (1986 ▶).

Experimental

Crystal data

[Ag₂(C₂₂H₃₀N₄)₂](PF₆)₂
M _r = 1206.68
Triclinic,
a = 11.3636 (15) Å
b = 11.4119 (15) Å
c = 11.9918 (15) Å
α = 63.528 (2)°
β = 89.335 (2)°
γ = 65.811 (2)°
V = 1241.7 (3) Å³
Z = 1
Mo Kα radiation
μ = 0.94 mm⁻¹
T = 100 K
0.24 × 0.14 × 0.08 mm

Data collection

Bruker APEXII DUO CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.806, T _max = 0.930
25433 measured reflections
7142 independent reflections
6512 reflections with I > 2σ(I)
R _int = 0.035

Refinement

R[F ² > 2σ(F ²)] = 0.051
wR(F ²) = 0.161
S = 1.16
7142 reflections
309 parameters
H-atom parameters constrained
Δρ_max = 3.16 e Å⁻³
Δρ_min = −1.23 e Å⁻³

Data collection: APEX2 (Bruker, 2009 ▶); cell refinement: SAINT (Bruker, 2009 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536810036524/lh5130sup1.cif

e-66-m1286-sup1.cif^{(24.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810036524/lh5130Isup2.hkl

e-66-m1286-Isup2.hkl^{(349.5KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C2—H2A⋯F3ⁱ	0.93	2.42	3.251 (6)	149
C5—H5A⋯F1ⁱⁱ	0.93	2.52	3.392 (6)	157
C7—H7B⋯F5ⁱⁱ	0.97	2.44	3.367 (6)	160
C11—H11A⋯F6ⁱⁱⁱ	0.97	2.44	3.364 (7)	159
C11—H11B⋯F2^iv	0.97	2.38	3.129 (7)	134

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) .

Acknowledgments

RAH, AW and SGT thank Universiti Sains Malaysia (USM) for the FRGS fund (203/PKIMIA/671115), short term grant (304/PKIMIA/639001) and RU grant (1001/PKIMIA/813023 and 1001/PKIMIA/811157). HKF and MH thank the Malaysian Government and Universiti Sains Malaysia for the Research University grant No. 1001/PFIZIK/811160. MH also thanks Universiti Sains Malaysia for a post-doctoral research fellowship.

supplementary crystallographic information

Comment

N-heterocyclic carbenes (NHCs) are now ubiquitous in their usage as ligands for transition metals (Tryg et al., 2005; Herrmann, 2002). Carbene ligands have some similarities to phosphine ligands, but metal- carbene complexes are often more stable than similar metal phosphine complexes (Herrmann et al., 1998; McGuinness et al., 1999). N-heterocyclic carbene complexes of different metals such as Pd and Ru have been used as catalysts for many reactions; for example C–C coupling reactions and reactions involving olefin metathesis (Tominaga et al., 2004; Magill et al., 2001). Among these metal -NHC complexes, the family of silver -NHC complexes have been receiving continuous attention since they are often used as convenient carbene transfer reagents to make other metal-NHC complexes (Yongbo et al., 2008). The chemistry of silver-NHC complexes has been recently reviewed (Garrison & Youngs, 2005; Kascatan-Nebioglu et al., 2007). The biological activity of many of the silver-NHC complexes as antimicrobial and antitumour were also confirmed (Özdemir et al., 2010; Medvetz et al., 2008).

The asymmetric unit of the title compound, (I), consists of one Ag^I cation, one 1,4-bis(3-butylimidazolium-1-yl-methyl)benzene ligand and one discrete hexafluoridophosphate anion (Fig. 1). The other half of the title complex is generated by an inversion center (1/2, 1/2, 0). Each Ag^I cation is bis-coordinated by two 1,4-bis(3-butylimidazolium-1-yl-methyl)benzene ligands. and displays an essentially linear geometry. The Ag1–C8 = 2.089 (4) Å bond length is comparable to the values reported for other [Ag(carbene)₂]⁺ complexes (Chen & Liu, 2003).

In the crystal structure, the cations and anions are linked together through intermolecular C2—H2A···F3; C5—H5A···F1; C7—H7B···F5; C11—H11A···F6 and C11—H11B···F2 hydrogen bonds, forming a three-dimensional network (Table 2 and Fig. 2).

Experimental

Silver oxide, Ag₂O, (0.13 g, 0.56 mmol) was added to a solution of 1,4-bis(3-butylimidazolium-1-yl-metyl)benzene bis(hexafluoroposphate) (0.30 g, 0.467 mmol) in acetonitrile (40 ml). The mixture was refluxed at (343–363)K for 20 hr in glassware wrapped with aluminium foil to exclude the light. The resulting mixture was filtered through celite to remove excess Ag₂O. After evaporation of the solvent, the white residue was washed with diethyl ether (2X5 ml) to afford the complex as a white powder. The yield was (0.25g, 45%), m.p = 550–552K. Crystal suitable for X-ray was obtained by slow evaporation of the salt solution in acetonitrile at 281K.