1,3-Bis(2-thienylmeth­yl)-4,5-dihydro­imidazolium trichlorido(η6-p-cymene)ruthenate(II)

Hakan Arslan; Don VanDerveer; İsmail Özdemir; Nevin Gürbüz; Yetkin Gök; Bekir Çetinkaya

doi:10.1107/S1600536809000464

. 2009 Jan 10;65(Pt 2):m165–m166. doi: 10.1107/S1600536809000464

1,3-Bis(2-thienylmethyl)-4,5-dihydroimidazolium trichlorido(η⁶-p-cymene)ruthenate(II)

Hakan Arslan ^a,^b,^*, Don VanDerveer ^c, İsmail Özdemir ^d, Nevin Gürbüz ^d, Yetkin Gök ^d, Bekir Çetinkaya ^e

PMCID: PMC2968218 PMID: 21581774

Abstract

The asymmetric unit of the title compound, (C₁₃H₁₅N₂S₂)[RuCl₃(C₁₀H₁₄)], contains a 1,3-(2-thienylmethyl)-4,5-dihydroimidazolium cation and a trichlorido(η ⁶-p-cymene)ruthenate(II) anion. The thiophene rings of the cation are disordered by an 180° rotation about the thiophene–CH₂ bonds with occupancies of 0.847 (5)/0.153 (5) and 0.700 (5)/0.300 (5), respectively. The Ru atom exhibits a distorted octahedral coordination with the benzene ring of the p-cymene ligand formally occupying three sites and three Cl atoms occupying the other three sites. The short C—N bond lengths in the imidazoline ring indicate partial electron delocalization within the N—C—N fragment. Cation and anions are connected through five intermolecular C—H⋯Cl hydrogen bonds and one C—H⋯π hydrogen bond, forming a three-dimensional hydrogen-bonded network.

Related literature

For the synthesis, see: Yaşar et al. (2008 ▶). Özdemir et al. (2008 ▶, 2007 ▶, 2005 ▶). For general background, see: Herrmann et al. (1995 ▶); Herrmann (2002 ▶); Arduengo & Krafczyc (1998 ▶). For related compounds, see: Arslan et al. (2007 ▶, 2005a ▶,b ▶) and references therein; Sonar et al. (2004 ▶, 2005a ▶,b ▶); Wagner et al. (2006a ▶,b ▶); Crundwell et al. (2002 ▶); Linehan et al. (2003 ▶); Liu et al. (2004 ▶); Navarro et al. (2006 ▶); Therrien et al. (2004 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

(C₁₃H₁₅N₂S₂)[RuCl₃(C₁₀H₁₄)]
M _r = 605.02
Triclinic,
a = 9.910 (2) Å
b = 11.600 (2) Å
c = 12.659 (3) Å
α = 84.95 (3)°
β = 67.05 (3)°
γ = 74.14 (3)°
V = 1288.8 (6) Å³
Z = 2
Mo Kα radiation
μ = 1.10 mm⁻¹
T = 153 (2) K
0.48 × 0.19 × 0.17 mm

Data collection

Rigaku AFC-8S Mercury CCD diffractometer
Absorption correction: multi-scan (REQUAB; Jacobson, 1998 ▶) T _min = 0.621, T _max = 0.836
11095 measured reflections
4557 independent reflections
4062 reflections with I > 2σ(I)
R _int = 0.019

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.084
S = 1.13
4557 reflections
285 parameters
H-atom parameters constrained
Δρ_max = 0.43 e Å⁻³
Δρ_min = −0.68 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2006 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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.

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536809000464/hg2465sup1.cif

e-65-0m165-sup1.cif^{(28.8KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536809000464/hg2465Isup2.hkl

e-65-0m165-Isup2.hkl^{(223.2KB, 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
C11—H11⋯Cl1ⁱ	0.96	2.62	3.450 (4)	144
C14—H14A⋯Cl1ⁱ	0.96	2.82	3.553 (4)	134
C19—H19A⋯Cl2ⁱ	0.96	2.81	3.671 (4)	150
C23—H23⋯Cl1ⁱⁱ	0.96	2.66	3.549 (4)	154
C14—H14B⋯Cg2ⁱⁱⁱ	0.96	2.83	3.784 (5)	171
C19—H19B⋯Cl1	0.96	2.86	3.759 (5)	157

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the S2,C20–C23 thiophene ring.

Acknowledgments

We thank the Technological and Scientific Research Council of Turkey TÜBİTAK-CNRS [TBAG-U/181 (106 T716)] and İnönü University Research Fund (BAP: 2008-Güdümlü3) for financial support.

supplementary crystallographic information

Comment

Metal-carbene compounds, such as N-heterocyclic carbene palladium and ruthenium complexes, are important catalysts that have a wide range of applications such as Suzuki-Miyaura, Sonogashira, Stille and Heck reactions (Herrmann 2002; Herrmann et al., 1995; Navarro et al., 2006; Arduengo & Krafczyc, 1998).

In previous papers, we have described the synthesis, characterization and applications of palladium, platinum and ruthenium N-heterocyclic carbene complexes as catalysts (Yaşar et al., 2008; Arslan et al., 2007, 2005a, 2005b, and references therein; Özdemir et al., 2008, 2007, 2005, and references therein). In view of these important attributes of N-heterocyclic carbene derivatives, we report here the crystal structure of one of them. The title compound consists 1,3-bis(thiophen-2-ylmethyl)-4,5-dihydro-1H-imidazolium cation and a trichloro(η⁶-p-cymene) ruthenium(II) anion. The molecular structure of the title compound, (I), is depicted in Fig. 1. Cation and anion groups are connected with five intermolecular C—H···Cl hydrogen bonds and one C—H···π hydrogen bond, forming a three-dimensional hydrogen-bonding network (Fig. 2).

A flip disorder of both thiophene rings in 1,3-bis(thiophen-2-ylmethyl)-4,5-dihydro-1H-imidazolium cation is observed. There are two positions of both thiophene rings, rotated by 180°. The crystal structure of the cation contains four disordered atoms, S1, S2, C16, and C21. The site occupancy factors refined to 0.847 (5) and 0.153 (5) for the S1—C15—C16—C17—C18 ring, and 0.700 (5) and 0.300 (5) for the S2—C20—C21—C22—C23 ring. A similar thiophene ring disorder has been observed in some thiophene derivatives, such as (Z)-3-(1-methyl-1H-indol-3-yl)-2-(thiophen-3-yl)acrylonitrile (Sonar et al., 2004), (Z)-2-(3-thienyl)-3-(3,4,5-trimethoxyphenyl)acrylonitrile (Sonar et al., 2005a), (Z)-3-(1H-Indol-3-yl)-2-(3-thienyl)acrylonitrile and (Z)-3-[1-(4-tert-butylbenzyl)-1H-indol-3-yl]-2-(3-thienyl)acrylonitrile (Sonar et al., 2005b), 1,2-di-3-thienyl-2-hydroxyethanone(3,3-thenoin) (Crundwell et al., 2002), 3-[2-(anthracen-9-yl)ethenyl] thiophene, (Wagner et al., 2006a), 2,5-bis(2-cyano-2-thienylvinyl)thiophene (Wagner et al., 2006b), and 1,4-diphenyl-2,3-dithien-3-ylcyclopentadien-1-one (Linehan et al., 2003). In addition, all thiophene rings in the cation are almost planar; the maximum deviations from the least squares planes are 0.019 (4)Å for C16 and 0.006 (6)Å for C22.

The coordination geometry of ruthenium is pseudooctahedral, with an average Ru—Cl bond distance of 2.430Å. The ruthenium atom exhibits a distorted octahedral coordination with the benzene ring of the p-cymene ligand formally occupying three sites and three chloride atoms occupying other three sites. The distance between the centroid of the p-cymene ring and ruthenium is 1.6493 (15) Å, which is longer than that reported in other ruthenium compounds (Liu et al., 2004; Therrien et al., 2004). All the other bond lengths in (I) are in normal ranges (Allen et al., 1987).

The imidazolidine ring is almost planar, the deviations from planarity of ring are N1 0.002 (3), C11 0.001 (4), N2 0.004 (3), C12 0.005 (4), C13 0.004 (4)Å. The some C—N bond lengths (N1—C11 = 1.307 (4)Å and N2—C11 = 1.302 (4)Å) for the imidazolidine ring are shorter than the average single C—N bond length of 1.48Å, thus showing double bond character in these C—N bonds. The other CN bonds length (N1—C13 1.458 (5), N1—C14 1.462 (4), N2—C19 1.460 (4) and N2—C12 1.466 (4)Å) is agree with 1.48Å C—N single bond lengths. This information indicates a partial electron delocalization within the N1—C11—N2 fragment.

The crystal packing is shown in Fig. 2. Five intermolecular C—H···Cl hydrogen bonds link the molecules of (I) and generate a three-dimensional hydrogen bonded framework. In addition, a C14 (x, y, z)-H···π (S2—C20—C21—C22—C23, thiophene ring; 1 - x, 1 - y, 2 - z) hydrogen bond is observed in the title compound, Table 1.

Experimental

A suspension of 1,3-bis(thiophen-2ylmethyl)-,4,5-dihydro-1H-imidazolium chloride (1.1 mmol), Cs₂CO₃(1.2 mmol) and [RuCl₂(p-cymene)] (0.5 mmol) was heated under reflux in degassed toluene (20 ml) for 7 h (Fig. 3). The reaction mixture was then filtered while hot, and the volume was reduced to about 10 ml before addition of n-hexane (15 ml). The precipitate formed was crystallized from CH₂Cl₂: hexane (5:10 ml) to give the complex as red-brown crystals. Yields: 0.208 g, 69%. M.p.: 227–228°C. ¹H NMR(CDCl₃) δ: 1.39 (d, 6H, J = 6.9 Hz, CH₃(C₆H₄)CH(CH₃)₂), 2.29 (s, 3H, CH₃(C₆H₄)CH(CH₃)₂), 3.21 (m, 1H, CH₃(C₆H₄)CH(CH₃)₂)_,3.79 (s, 4H, NCH₂CH₂N), 4.12 (s, 4H, CH₂C₄H₃S), 5.29 and 5.58 (d, 4H, J = 5.8 Hz, CH₃(C₆H₄)CH(CH₃)₂), 7.03–7.68 (m, 6H, C₄H₃S), 8.99 (s, 1H, 2-CH). ¹³C NMR (CDCl₃) δ: 18.6 (CH₃(C₆H₄)CH(CH₃)₂), 22.3 (CH₃(C₆H₄)CH(CH₃)₂), 30.8 (CH₃(C₆H₄)CH(CH₃)₂), 47.0 (NCH₂CH₂N), 47.1 (CH₂C₄H₃S), 79.6, 81.8, 96.5 and 100.8 (CH₃(C₆H₄)CH(CH₃)₂), 126.7, 127.5, 129.1 and 135.2 (C₄H₃S), 159.3 (2-CH). Anal. Calc. for C₂₃H₂₉S₂N₂RuCl₃: C, 45.66; H, 4.83; N, 4.63%. Found: C, 45.71; H, 4.89; N, 4.69%.