(Diethyl ether){1-[2-(1-methyl-1H-imidazol-2-yl-κN 3)-1,1-diphenylethyl]-(1,2,3,3a,7a-η)-indenyl}lithium(I)

In the title compound, [Li(C27H23N2)(C4H10O)], the Li atom possesses a nearly planar trigonal coordination environment (assuming the cyclopentadienyl ring of the indenyl group occupies one coordination place). The diethyl ether ligand adopts a nearly planar W-type conformation.

In the title compound, [Li(C 27 H 23 N 2 )(C 4 H 10 O)], the Li atom possesses a nearly planar trigonal coordination environment (assuming the cyclopentadienyl ring of the indenyl group occupies one coordination place). The diethyl ether ligand adopts a nearly planar W-type conformation.

Experimental
Crystal data [Li(C 27
Financial support from the National Natural Science Foundation of China (project No. B020205) is gratefully acknowledged. The authors are grateful to Mr Sun Wei for his help in measuring the NMR spectra. MVB is especially thankful to his former permanent co-author and old friend, Dr Andrei V. Churakov, for his invaluable advices in preparation of the material for this contribution.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DN2437).

Experimental
All operations were performed in all-sealed glassware with application of the high-vacuum line technique (residual partial pressure of non-condensable gases below 1.5 × 10 -3 torr), with traces of oxygen and moisture excluded. Solutions of (1-methyl-1H-imidazol-2-yl)methyllithium (adduct with THF 2: 1) [see (Krut'ko et al., 2006)] (2.234 g, 16.2 mmol) and 1-diphenylmethylidene-1H-indene (4.535 g, 16.2 mmol) in THF (total amount 100 ml) were mixed and heated at 60 °C for 1 h. The dark-blue solution was concentrated till dryness and the rest was extracted with diethyl ether that gave 7.42 g (86%) of the lithium salt Ia (adduct with TWO molecules of THF, 1 H NMR spectral data) as dark-blue crystalline material. Single crystal of I (adduct with one molecule of THF) suitable for X-ray diffraction analysis was grown up from hot ether solution (slow cooling within 60 -30 °C range, sealed vessel). Green crystals of I in THF-d 8 form pink solution. Non-H atoms were refined anisotropically. H atoms were treated as riding atoms with distances C-H = 0.96 (CH 3 ), 0.97 (CH 2 ), 0.93 Å (C Ar H), and U iso (H) = 1.5 U eq (C), 1.2 U eq (C), and 1.2 U eq (C), respectively. For Et 2 O atoms C41 through C44 and O1, the components of the anisotropic displacements along 1-2 and 1-3 directions were restrained to be the same with a standard uncertainty of 0.005 Å 2 . Fig. 1. Molecular structure of 1. Thermal ellpsoids are drawn at 30% probability level. All hydrogen atoms are omitted for clarity. Bonds from Li1 to N2, O1, and Cp cent are drawn as dashed lines.

Figures
Crystal data [Li(C 27