1,3-Bis(thio­phen-2-ylmeth­yl)-3,4,5,6-tetra­hydro­pyrimidinium trichlorido(η6-p-cymene)ruthenate(II)

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

doi:10.1107/S1600536808042773

. 2008 Dec 20;65(Pt 1):m111–m112. doi: 10.1107/S1600536808042773

1,3-Bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium 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: PMC2968014 PMID: 21581477

Abstract

The asymmetric unit of the title compound, (C₁₄H₁₇N₂S₂)[Ru(C₁₀H₁₄)Cl₃], contains a 1,3-bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium cation and a trichlorido(η⁶-p-cymene)ruthenate(II) anion. The Ru atom exhibits a distorted octahedral coordination with the benzene ring of the p-cymene ligand formally occupying three sites and three chloride atoms occupying the other three sites. The N—C bond lengths of the N—C—N unit of the pyrimidinium cation are shorter than the average single C—N bond length of 1.48 Å, thus showing double-bond character, indicating a partial electron delocalization within the N—C—N fragment. The pyrimidine ring has an envelope conformation. Four intermolecular C—H⋯Cl hydrogen bonds generate a three-dimensional hydrogen-bonded framework.

Related literature

For the synthesis, see: Yaşar et al. (2008 ▶); Özdemir et al. (2005a ▶, 2005b ▶, 2007 ▶, 2008 ▶). For general background, see: Herrmann et al. (1995 ▶); Herrmann (2002 ▶); Littke & Fu (2002 ▶); Özdemir et al. (2005c ▶); Arduengo & Krafczyc (1998 ▶); Navarro et al. (2006 ▶). For related compounds, see: Liu et al. (2004 ▶); Therrien et al. (2004 ▶); Arslan et al. (2004a ▶,b ▶, 2005a ▶,b ▶, 2007a ▶,b ▶,c ▶). For puckering and asymmetry parameters, see: Cremer & Pople (1975 ▶); Nardelli (1983 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

(C₁₄H₁₇N₂S₂)[Ru(C₁₀H₁₄)Cl₃]
M _r = 619.05
Triclinic,
a = 9.989 (2) Å
b = 11.404 (2) Å
c = 12.922 (3) Å
α = 82.10 (3)°
β = 67.61 (3)°
γ = 72.59 (3)°
V = 1298.2 (6) Å³
Z = 2
Mo Kα radiation
μ = 1.09 mm⁻¹
T = 153 (2) K
0.24 × 0.12 × 0.07 mm

Data collection

Rigaku Mercury CCD diffractometer
Absorption correction: multi-scan (REQAB; Jacobson, 1998 ▶) T _min = 0.780, T _max = 0.928
9185 measured reflections
4606 independent reflections
4048 reflections with I > 2σ(I)
R _int = 0.020

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.076
S = 1.12
4606 reflections
292 parameters
H-atom parameters constrained
Δρ_max = 0.61 e Å⁻³
Δρ_min = −0.58 e Å⁻³

Data collection: CrystalClear (Rigaku/MSC, 2001 ▶); 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/S1600536808042773/hg2457sup1.cif

e-65-0m111-sup1.cif^{(30KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808042773/hg2457Isup2.hkl

e-65-0m111-Isup2.hkl^{(225.6KB, 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
C1—H1⋯Cl1ⁱ	0.96	2.64	3.519 (4)	153
C1—H1⋯Cl2ⁱ	0.96	2.82	3.478 (4)	126
C10—H10A⋯Cl3ⁱ	0.96	2.75	3.654 (4)	156
C14—H14⋯Cl1ⁱⁱ	0.96	2.63	3.584 (4)	175

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

Acknowledgments

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

supplementary crystallographic information

Comment

N-heterocyclic carbene ligands have emerged as one of the most important classes of compounds used for catalytic reactions such as Suzuki-Miyura, Sonogashira, Stille and Heck reactions (Herrmann et al., 1995; Navarro et al., 2006; Arduengo & Krafczyc, 1998; Herrmann, 2002; Littke & Fu, 2002). Recently, we have focused on the synthesis, characterization and application of palladium, platinum and ruthenium N-heterocyclic carbene complexes as catalysts (Yaşar et al., 2008; Arslan et al., 2007a, 2007b,2007c, 2004a, 2004b, 2005a, 2005b).

To continue our studies on this topic (Özdemir et al. (2005a, 2005b, 2005c, 2007, 2008)), we report herein the X-ray crystal structure of an N-heterocyclic carbene cation (1,3-bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium) and trichloro(η⁶-p-cymene)ruthenat(II) anion compound. The molecular structure of the title compound, (I), is depicted in Fig. 1.

The structure of the title compound consists of [C₁₄H₁₇N₂S₂]⁺ cations and [C₁₀H₁₄Cl₃Ru]^- anions. These groups are connected with four intermolecular C—H···Cl hydrogen bonds, thus forming a three-dimensional hydrogen-bonded network (Fig. 2). The intermolecular contacts are also listed in Table 1.

The thiophene rings are almost planar, while the pyrimidin ring is not planar. The deviations from planarity for the pyrimidin ring are C1 0.111 (4), N1 0.013 (3), C2 0.207 (4), C3 0.328 (4), C4 0.229 (4), and N2 0.010 (3) Å. The puckering parameters (Cremer & Pople, 1975) and the smallest displacement asymmetry parameters (Nardelli, 1983) for the pyrimidin ring are Q = 0.464 (4) Å, Θ = 55.1 (5) ° and φ = 236.6 (5)°, q₂ = 0.381 (4) Å, and ΔC₂(C1) = 2.8 (4), ΔC_s(C1) = 66.6 (3). According to these results, the pyrimidin ring adopts an envelope conformation.

The coordination geometry of ruthenium is pseudooctahedral, with an average Ru—Cl bond distance of 2.427 Å. 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 three other sites. The distance between the centroid of the p-cymene ring and ruthenium atom is 1.972 (3) Å, which is longer than 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).

Some C—N bond lengths (N1—C1 = 1.313 (4) Å and N2—C1 = 1.312 (4) Å) for the 1,3-bis(thiophen-2-ylmethyl)-3,4,5,6-tetrahydropyrimidinium cation are shorter than the average single C—N bond length of 1.48 Å, thus showing double bond character in these C—N bonds. The other C—N bond lengths (N1—C2 1.468 (4), N1—C10 1.475 (4), N2—C5 1.466 (4) and N2—C4 1.469 (4) Å) are in agreement with the expected 1.48 Å C—N single bond lengths. This information indicates a partial electron delocalization within the N1—C1—N2 fragment.

Experimental

A suspension of 1,3-bis(thiophen-2ylmethyl)-3,4,5,6-tetrahydropyrimidinium 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. The reaction mixture was then filtered while hot, and the volume was reduced to about 10 ml before addition of n-hexane (15 ml) (Scheme 2). The precipitate formed was crystallized from CH₂Cl₂/diethylether (5:15 mL) to give complex as red-brown crystals. Yields: 0.232 g; 75%. M.p.: 235–236 ^oC. ¹H NMR (CDCl₃) δ: 1.38 (d, 6H, J = 6.9 Hz, CH₃(C₆H₄)CH(CH₃)₂), 1.86 (quin., 2H, J = 6 Hz, NCH₂CH₂CH₂N), 2.31 (s, 3H,CH₃(C₆H₄)CH(CH₃)₂), 3.17 (m, 1H, CH₃(C₆H₄)CH(CH₃)₂)_,3.25 (t, 4H, J = 6 Hz, NCH₂CH₂CH₂N), 4.75 (s, 4H, CH₂C₄H₃S), 5.32 and 5.57 (d, 4H, J = 5.8 Hz, CH₃(C₆H₄)CH(CH₃)₂), 7.05–7.64 (m, 6H, C₄H₃S), 8.91 (s, 1H, 2-CH). ¹³C NMR (CDCl₃) δ: 19.0 (CH₃(C₆H₄)CH(CH₃)₂), 19.1 (NCH₂CH₂CH₂N), 22.3 (CH₃(C₆H₄)CH(CH₃)₂), 30.8 (CH₃(C₆H₄)CH(CH₃)₂), 42.3 (NCH₂CH₂CH₂N), 54.5 (CH₂C₄H₃S), 79.7, 81.8, 96.4 and 100.8 (CH₃(C₆H₄)CH(CH₃)₂), 126.7, 127.5, 129.2 and 135.9 (C₄H₃S), 159.7 (2-CH). Anal. Calc. for C₂₄H₃₁S₂N₂RuCl₃: C, 46.56; H, 5.05; N, 4.53%. Found: C, 47.19; H, 5.15; N, 4.71%.