1,3-Bis(2-cyano­benz­yl)imidazolium bromide

Rosenani A Haque; Safaa A Ahmed; Zulikha H Zetty; Madhukar Hemamalini; Hoong-Kun Fun

doi:10.1107/S1600536811048951

. 2011 Nov 30;67(Pt 12):o3462. doi: 10.1107/S1600536811048951

1,3-Bis(2-cyanobenzyl)imidazolium bromide

Rosenani A Haque ^a, Safaa A Ahmed ^b, Zulikha H Zetty ^a, Madhukar Hemamalini ^c, Hoong-Kun Fun ^c,^*,^‡

PMCID: PMC3239090 PMID: 22199938

Abstract

In the title salt, C₁₉H₁₅N₄ ⁺·Br⁻, the central imidazole ring makes dihedral angles of 83.1 (2) and 87.6 (2)° with the terminal benzene rings. The dihedral angle between the terminal benzene rings is 6.77 (19)°; the cyanide substituents have an anti orientation. In the crystal, the cations and anions are linked via C—H⋯N and C—H⋯Br hydrogen bonds, forming sheets lying parallel to the ac plane.

Related literature

For details and applications of N-heterocylic carbene, see: Wanzlick & Kleiner (1961 ▶); Fahlbusch et al. (2009 ▶); Demir et al. (2009 ▶); Grasa et al. (2002 ▶); Buchowicz et al. (2006 ▶); Marko et al. (2002 ▶).

Experimental

Crystal data

C₁₉H₁₅N₄ ⁺·Br⁻
M _r = 379.26
Monoclinic,
a = 9.0661 (9) Å
b = 8.0357 (9) Å
c = 24.697 (3) Å
β = 95.651 (2)°
V = 1790.5 (3) Å³
Z = 4
Mo Kα radiation
μ = 2.30 mm⁻¹
T = 296 K
0.36 × 0.17 × 0.10 mm

Data collection

Bruker APEXII DUO CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2009 ▶) T _min = 0.494, T _max = 0.799
12922 measured reflections
4066 independent reflections
2486 reflections with I > 2σ(I)
R _int = 0.034

Refinement

R[F ² > 2σ(F ²)] = 0.049
wR(F ²) = 0.149
S = 1.02
4066 reflections
217 parameters
H-atom parameters constrained
Δρ_max = 1.14 e Å⁻³
Δρ_min = −0.82 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 datablock(s) global, I. DOI: 10.1107/S1600536811048951/hb6514sup1.cif

e-67-o3462-sup1.cif^{(19.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811048951/hb6514Isup2.hkl

e-67-o3462-Isup2.hkl^{(195.3KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536811048951/hb6514Isup3.cml

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
C1—H1A⋯Br1ⁱ	0.93	2.70	3.531 (4)	149
C2—H2A⋯Br1ⁱⁱ	0.93	2.67	3.579 (4)	165
C3—H3A⋯N4ⁱⁱⁱ	0.93	2.50	3.377 (6)	157
C4—H4B⋯Br1ⁱ	0.97	2.86	3.730 (4)	149
C7—H7A⋯N4^iv	0.93	2.60	3.390 (5)	144
C10—H10A⋯Br1^v	0.93	2.88	3.678 (4)	144

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

Acknowledgments

RAH, SAA and ZZH thank Universiti Sains Malaysia for the FRGS fund (203/PKIMIA/671115) and RU grant (1001/PKIMIA/811157) (to RAH and ZZH) and the University of Tikrit for research leave (to SSA). 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

Since the investigation of N-heterocyclic carbene (NHC) chemistry by Wanzlick and Kleiner (1961), NHCs have played a major role as ligands in coordination and organometallic chemistry (Fahlbusch et al., 2009). During the past decades it has been proven as an alternative to tertiary phosphines in homogeneous catalysis. Due to NHC's strong σ-donating and negligible π-accepting characters, they are compatible with metals in a variety of oxidation states. NHC can stabilize catalytically active intermediates (Demir et al., 2009) making it a very versatile ligand system. NHC complexes with every transition metal are now known and their applications especially in the area of catalysis cover a broad spectrum such as hydroboration (Grasa et al., 2002), polymerization reactions (Buchowicz et al., 2006) and hydrosilation (Marko et al., 2002). Furthermore, NHCs are easy to handle, stable and inexpensive resulting in their receiving a great deal of interest compared to other types of carbenes.

In (I), the asymmetric unit contains a 1,3-Bis(2-cyanobenzyl)imidazolium cation and a bromide anion. The central imidazole (N1,N2/C1–C3) ring makes dihedral angles of 83.1 (2) and 87.6 (2)° with the terminal phenyl (C5–C10 and C12–C17) rings. The dihedral angle between the two terminal phenyl (C5–C10 and C12–C17) rings is 6.77 (19)°.

In the crystal, (Fig. 2), the cations and anions are linked via C—H···N and C—H···Br hydrogen bonds (Table 1), forming two-dimensional networks parallel to the ac-plane.

Experimental

Imidazole (0.3 g, 3.7 mmol) and potassium hydroxide (0.2 g, 5.5 mmol) was stirred for 2 h in 25 mL of ethanol. 2-Bromomethyl benzonitrile (1.8 g, 9.2 mmol) was then added and the mixture was refluxed at 80°C for 24 h. The resulting clear crystals were isolated by decantation, washed with fresh n-hexane (2 X 3 ml) and then left to dry at ambient temperature. Yield: 1.3 g, (94%); m.p: 233–234°C. Colourless blocks were obtained by slow evaporation of the salt solution in ethanol at ambient temperature.