(η6-p-Cymene)(1,3-dimesityl-2,3-dihydro-1H-imidazol-2-yl­idene)bis­(pentafluorobenzoato-κO)ruthenium(II) dichloro­methane disolvate

Konstantin Dorst; Wolfgang Frey; Dongren Wang; Michael Buchmeiser

doi:10.1107/S1600536812049513

. 2012 Dec 8;69(Pt 1):m28. doi: 10.1107/S1600536812049513

(η⁶-p-Cymene)(1,3-dimesityl-2,3-dihydro-1H-imidazol-2-ylidene)bis(pentafluorobenzoato-κO)ruthenium(II) dichloromethane disolvate

Konstantin Dorst ^a, Wolfgang Frey ^b, Dongren Wang ^a, Michael Buchmeiser ^a,^*

PMCID: PMC3588321 PMID: 23476327

Abstract

The title compound, [Ru(C₇F₅O₂)₂(C₁₀H₁₄)(C₂₁H₂₄N₂)]·2CH₂Cl₂, is formed as an orange crystalline powder by the reaction of RuCl₂(p-cymene)(IMes) and AgOCOC₆F₅ in anhydrous tetrahydrofuran (IMes = 1,3-dimesityl-2,3-dihydro-1H-imidazol-2-ylidene). The asymetric unit consists of two independent [Ru(C₆F₅COO)₂(η⁶-p-cymene)(IMes)] complexes and four dichloromethane solvent molecules. In each complex molecule, the Ru atom presents a pseudo-octahedral environment with the p-cymene ligand occupying three facial coordination sites, while the remaining coordination positions are occupied by the O atoms of the pentafluorobenzoate ligands and by the imidazolylidene ligand.

Related literature

For general background to latent olefin metathesis catalysts, see: Monsaert et al. (2009 ▶). For ring-closing metathesis (RCM) studies of Ru^II-p-cymene, see: Jafarpour et al. (1999 ▶). For related synthetic procedures and structures, see: Zhang et al. (2006 ▶); Buchmeiser et al. (2007 ▶). For their applications in UV-triggerable-ROMP, see: Wang et al. (2008 ▶, 2010 ▶).

Experimental

Crystal data

[Ru(C₇F₅O₂)₂(C₁₀H₁₄)(C₂₁H₂₄N₂)]·2CH₂Cl₂
M _r = 1131.70
Monoclinic,
a = 18.0951 (11) Å
b = 22.4608 (14) Å
c = 23.4293 (14) Å
β = 104.782 (3)°
V = 9207.2 (10) Å³
Z = 8
Mo Kα radiation
μ = 0.66 mm⁻¹
T = 100 K
0.63 × 0.30 × 0.16 mm

Data collection

Bruker Kappa APEXII DUO diffractometer
Absorption correction: multi-scan (Blessing, 1995 ▶) T _min = 0.653, T _max = 0.746
88410 measured reflections
21150 independent reflections
16066 reflections with I > 2σ(I)
R _int = 0.037

Refinement

R[F ² > 2σ(F ²)] = 0.059
wR(F ²) = 0.164
S = 1.09
21150 reflections
1243 parameters
H-atom parameters constrained
Δρ_max = 5.08 e Å⁻³
Δρ_min = −2.32 e Å⁻³

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 2008 ▶); software used to prepare material for publication: publCIF (Westrip, 2010 ▶).

Supplementary Material

Click here for additional data file.^{(103.2KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812049513/im2412sup1.cif

e-69-00m28-sup1.cif^{(103.2KB, cif)}

Click here for additional data file.^{(1MB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812049513/im2412Isup2.hkl

e-69-00m28-Isup2.hkl^{(1MB, hkl)}

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

Acknowledgments

Finalcial support provided by the DFG (BU 2174/8–1) is gratefully acknowledged.

supplementary crystallographic information

Comment

In the last years, the design and synthesis of latent olefin metathesis precatalysts has received considerable attention. Due to their latency, they exhibit no catalytic activity at low (usually ambient) temperature in the presence of monomer or substrate, but can be triggered quantitatively to a highly active form. This activation can be caused by a variety of different stimuli, e.g., light activation to initiate metathesis reactions. Such precatalysts are of particular interest in technical applications of ROMP, since they allow for being mixed with the monomers, its storage over a longer period of time even at elevated temperatures without concomitant polymerization (Buchmeiser et al. 2007, Monsaert et al. 2009). The title compound (Figure 1), an intermediate product for the synthesis of a photo-latent metathesis catalyst, was obtained by the reaction of RuCl₂(p-cymene)(IMes) and AgOCOC₆F₅ in anhydrous THF (IMes = 1,3-dimesityl-2,3-dihydro-1H-imidazol-2-ylidene). It crystallizes in the space group P2₁/n (Z=8) with accompanying CH₂Cl₂ solvate molecules. Selected geometric parameters are given in table 1. The structure exhibits a typical three legged piano stool structure with RuII coordinated by one carbon atom of the N-heterocyclic carbene ligand and two oxygen atoms of the pentafluorobenzoate ligands. The coordination geometry around Ru is that of a distorted octahedron in which three sites are occupied by the η⁶-p-cymene ligand, two by the pentafluorobenzoate ligands and one by the N-heterocyclic carbene. The structure is closely similar to that of recently reported compound Ru(CF₃COO)(p-cymene)(IMes) (Zhang et al. 2006).

Experimental

A solution of silver pentafluorobenzoate (356.9 mg, 1.12 mmol) in 10 ml of anhydrous THF was added to a solution of RuCl₂(IMes)(p-cymene) (328.5 mg, 0.54 mmol) in 10 ml of anhydrous THF under stirring. After 4 h the mixture was filtered through a short bed of celite and THF was removed in vacuo. Dichloromethane was added to dissolve the residues and the solution was filtered through glass-fiber paper and concentrated in vacuo. Diethyl ether was layered over the red, saturated CH₂Cl₂ solution. Red crystals suitable for X-ray analysis formed at -36°C. Yield: 310 mg (60%).