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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 80| Part 6| June 2024| Pages 620-624
https://doi.org/10.1107/S2056989024004237

Crystal structure of a three-coordinate lithium complex with monodentate phenyl­oxazoline and hexa­methyl­disilyl­amide ligands

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José Severiano Carneiro Neto,a Eduardo Mariano Iwaya,a Francielli Sousa Santanaa* and Jaísa Fernandes Soaresa

aDepartamento de Química, Universidade Federal do Paraná, Centro Politécnico, Jardim das Américas, 81530-900, Curitiba-PR, Brazil
*Correspondence e-mail: francielli.s.santana@ufpr.br

Edited by G. Ferrence, Illinois State University, USA (Received 6 February 2024; accepted 8 May 2024; online 17 May 2024)

The reaction of lithium hexa­methyl­disilyl­amide, [Li{N(Si(CH3)3)2}] (LiHMDS), with 4,4-dimethyl-2-phenyl-2-oxazoline (Phox, C11H13NO) in hexane produced colourless crystals of bis­(4,4-dimethyl-2-phenyl-2-oxazoline-κN)(hexa­methyl­disilyl­amido-κN)lithium, [Li(C6H18NSi2)(C11H13NO)2] or [Li{N(Si(CH3)3)2}(Phox)2] in high yield (89%). Despite the 1:1 proportion of the starting materials in the reaction mixture, the product formed with a 1:2 amide:oxazoline ratio. In the unit cell of the C2/c space group, the neutral mol­ecules lie on twofold rotation axes coinciding with the Li—N(amide) bonds. The lithium(I) centre adopts a trigonal–planar coordination geometry with three nitro­gen donor atoms, one from the HMDS anion and two from the oxazolines. All ligands are monodentate. In the phenyl­oxazoline units, the dihedral angle defined by the five-membered heterocyclic rings is 35.81 (5)°, while the phenyl substituents are approximately face-to-face, separated by 3.908 (5) Å. In the amide, the methyl groups assume a nearly eclipsed arrangement to minimize steric repulsion with the analogous substituents on the oxazoline rings. The non-covalent inter­actions in the solid-state structure of [Li{N(Si(CH3)3)2}(Phox)2] were assessed by Hirshfeld surface analysis and fingerprint plots. This new compound is attractive for catalysis due to its unique structural features.

CCDC reference: 2354028

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1. Chemical context

Oxazolines are a family of cyclic amino­ethers characterized by five-membered heterocyclic rings containing one unsaturation. They can be prepared using various methods that typically involve the cyclization of an amino­alcohol as a general process (Mulahmetovic & Hargaden, 2019[Mulahmetovic, E. & Hargaden, G. C. (2019). Mini-Rev. Org. Chem. 16, 507-526.]). These compounds have been widely used in synthesis, catalysis, and as proligands in coordination chemistry (Connon et al., 2021[Connon, R., Roche, B., Rokade, B. V. & Guiry, P. J. (2021). Chem. Rev. 121, 6373-6521.]; Liu et al., 2016[Liu, X., Chen, P. & Wu, F. (2016). Chin. J. Org. Chem. 36, 1797-1804.]; Rasappan et al., 2008[Rasappan, R., Laventine, D. & Reiser, O. (2008). Coord. Chem. Rev. 252, 702-714.]; McManus & Guiry, 2004[McManus, H. A. & Guiry, P. J. (2004). Chem. Rev. 104, 4151-4202.]; Gómez et al., 1999[Gómez, M., Muller, G. & Rocamora, M. (1999). Coord. Chem. Rev. 193-195, 769-835.]).

Metal complexes containing monodentate, N-donor monooxazoline ligands are reasonably frequent in the solid state (Huang et al., 2014[Huang, P., Wang, Y. X., Yu, H. F. & Lu, J. M. (2014). Organometallics, 33, 1587-1593.]; Del Río & Gossage, 2009[Río, I. del & Gossage, R. A. (2009). Acta Cryst. E65, m103-m104.]; Barclay et al., 2003[Barclay, T. M., del Río, I., Gossage, R. A. & Jackson, S. M. (2003). Can. J. Chem. 81, 1482-1491.]; Valk et al., 1994[Valk, J. M., Maassarani, F., van der Sluis, P., Spek, A. L., Boersma, J. & van Koten, G. (1994). Organometallics, 13, 2320-2329.]; Michelin et al., 1991[Michelin, R. A., Bertani, R., Mozzon, M., Bombieri, G., Benetollo, F. & Angelici, R. J. (1991). Organometallics, 10, 1751-1757.]). In the case of 2-phenyl­oxazolines (Phox), which are of inter­est to this work, the chelating behaviour is more common and involves a second donor atom, generally N, O, S or Se, in the ortho position of the aromatic ring (Volpe et al., 2010[Volpe, E. C., Manke, D. R., Bartholomew, E. R., Wolczanski, P. T. & Lobkovsky, E. B. (2010). Organometallics, 29, 6642-6652.]; Bottini et al., 2010[Bottini, R. C. R., Gariani, R. A., Cavalcanti, C. O., de Oliveira, F., da Rocha, N. L. G., Back, D., Lang, E. S., Hitchcock, P. B., Evans, D. J., Nunes, G. G., Simonelli, F., de Sá, E. L. & Soares, J. F. (2010). Eur. J. Inorg. Chem. 2010, 2476-2487.]). Phox complexes of d-block metals have been studied as catalysts (Abu-Elfotoh, 2017[Abu-Elfotoh, A. M. (2017). Tetrahedron Lett. 58, 4750-4754.]; Bagherzadeh et al., 2008[Bagherzadeh, M., Latifi, R., Tahsini, L. & Amini, M. (2008). Catal. Commun. 10, 196-200.]; Kandasamy et al., 2004[Kandasamy, K., Singh, H. B., Butcher, R. J. & Jasinski, J. P. (2004). Inorg. Chem. 43, 5704-5713.]).

Lithium hexa­methyl­disilyl­amide (LiHMDS), in turn, was first crystallographically characterized as a cyclic, trimeric compound with alternating nitro­gen and lithium atoms in a planar six-membered ring (Mootz et al., 1969[Mootz, D., Zinnius, A. & Böttcher, B. (1969). Angew. Chem. 81, 398-399.]). This complex and other bulky MN(SiR3)2 bis­(tri­alkyl­sil­yl)amides (M = alkali metal; R = Me, Et, iPr, tBu, Ph, etc.) are widely used in organic synthesis as deprotonating agents due to their low nucleophilicity and strong Brønsted basicity (Neufeld et al., 2016[Neufeld, R., Michel, R., Herbst-Irmer, R., Schöne, R. & Stalke, D. (2016). Chem. A Eur. J. 22, 12340-12346.]; Tang et al., 2005[Tang, Y., Zakharov, L. N., Rheingold, A. L. & Kemp, R. A. (2005). Polyhedron, 24, 1739-1748.]; Beak et al., 1996[Beak, P., Basu, A., Gallagher, D. J., Park, Y. S. & Thayumanavan, S. (1996). Acc. Chem. Res. 29, 552-560.]), and in coordination chemistry as sterically demanding starting materials to impose low coordination numbers (Mohamed, 2010[Mohamed, A. H. (2010). Coord. Chem. Rev. 254, 1918-1947.]; Power, 2004[Power, P. P. (2004). J. Organomet. Chem. 689, 3904-3919.]). In both fields, the high solubility conferred by the tri­methyl­silyl substituents in a wide range of non-polar organic solvents is an advantage of working with HMDS− in synthetic procedures (Ojeda-Amador et al., 2016[Ojeda-Amador, A. I., Martínez-Martínez, A. J., Kennedy, A. R. & O'Hara, C. T. (2016). Inorg. Chem. 55, 5719-5728.]).

In this paper, we report the synthesis, crystal and mol­ecular structures of the mononuclear, three-coordinate lithium(I) complex [Li{N(Si(CH3)3)2}(Phox)2] (Phox = 4,4-dimethyl-2-phenyl-2-oxazoline). The product crystallized directly from the reaction mixture at 253 K, following an attempt to deprotonate the oxazoline by reaction between [LiN(Si(CH3)3)2] and Phox in hexane.

[Scheme 1]

2. Structural commentary

The [Li{N(Si(CH3)3)2}(Phox)2] complex crystallizes in the C2/c space group as a discrete mol­ecular unit with no solvent in the unit cell. The asymmetric unit comprises half of the anionic hexa­methyl­disilyl­amide ligand, {N0.5(Si(CH3)3)}0.5–, and one neutral 4,4-dimethyl-2-phenyl-2-oxazoline mol­ecule, both coordinated to the lithium centre solely by the nitro­gen atoms. Proper rotation about a twofold axis passing through the Li—N1 bond (symmetry operation −x + 1, y, −z + [{1\over 2}]) leads to the complete, neutral lithium complex mol­ecule. The coordination sphere of lithium(I) presents a trigonal–planar geometry with no deviation from planarity, Fig. 1[link]. In this environment, the two five-membered oxazoline rings (each with a planarity deviation of 0.082°) form a dihedral angle (α) of 35.81 (5)°. At the same time, the distance between the approximately face-to-face phenyl substituents equals 3.908 (5) Å, Fig. 2[link].

[Figure 1]
Figure 1
View of the mol­ecular structure of [Li{N(Si(CH3)3)2}(Phox)2], with the atom-numbering scheme. Hydrogen atoms are omitted for clarity. Displacement ellipsoids are drawn at the 50% probability level. Symmetry code: (i) −x + 1, y, −z + [{1\over 2}].
[Figure 2]
Figure 2
Distance between the phenyl rings (red dashed line) and dihedral angle (α) between the five-membered oxazoline rings. Grey: carbon; red: oxygen; blue: nitro­gen; light blue: silicon; purple: lithium. Displacement ellipsoids are drawn at the 50% probability level. Hydrogen atoms are excluded for clarity.

The Li—N bonds are 2.126 (2) and 1.942 (3) Å long for the oxazoline and amide ligands, respectively. Such a significant bond-length variation comes from the stronger inter­action of the lithium centre with the anionic amide nitro­gen (higher negative density charge) compared to the neutral oxazoline. Similar 0.1–0.2 Å bond-distance differences have been used to distinguish ‘ionic’ from ‘dative’ Li—N bonds (Henderson et al., 1997[Henderson, K. W., Dorigo, A. E., Liu, Q.-L. & Williard, P. G. (1997). J. Am. Chem. Soc. 119, 49, 11855-11863.]; Gregory et al., 1991[Gregory, K. P., Schleyer, P., v, R. & Snaith, R. (1991). Adv. Inorg. Chem. 37, 47-142.]) and were reported earlier for other mononuclear, trigonal planar Li complexes containing an amide (N{SiR3}2−, NArH−) and a neutral ligand such as sparteine, N,N,N′,N′-tetra­methyl­ethylenedi­amine, and N′,N′,N′′,N′′,N′′′-tetra­methyl­ethylenedi­amine (Clark et al., 2009[Clark, N. M., García-Álvarez, P., Kennedy, A. R., O'Hara, C. T. & Robertson, G. M. (2009). Chem. Commun. pp. 5835-5837.]; Henderson et al., 1997[Henderson, K. W., Dorigo, A. E., Liu, Q.-L. & Williard, P. G. (1997). J. Am. Chem. Soc. 119, 49, 11855-11863.]; Fjeldberg et al., 1984[Fjeldberg, T., Hitchcock, P. B., Lappert, M. F. & Thorne, A. J. (1984). J. Chem. Soc. Chem. Commun. pp. 822-824.]). The Li—Noxazoline bond is longer than analogous bonds reported for dimeric lithium(I) complexes with bidentate [Jantzi et al., 2006[Jantzi, K. L., Guzei, I. A. & Reich, H. J. (2006). Organometallics, 25, 5390-5395.]; average 2.044 (3) Å] and tridentate oxazoline ligands [Stol et al., 2005[Stol, M., Snelders, D. J., de Pater, J. J., van Klink, G. P., Kooijman, H., Spek, A. L. & van Koten, G. (2005). Organometallics, 24, 743-749.]; average 1.996 (3) Å]; the difference can be ascribed to distinct Li+ coordination numbers and ligands' denticities and bulk. To our knowledge, the title compound is the first example of a monodentate oxazoline complex of lithium(I) structurally characterized in the solid state.

In [Li{N(Si(CH3)3)2}(Phox)2], the methyl groups of the hexa­methyl­disilyl­amide moieties are nearly eclipsed (Fig. 3[link]), with a dihedral angle of 5.80 (7)° between the C3—Si—N1 and the C3i—Sii—N1 planes. Additionally, if one defines a vector connecting the symmetry-related Si and Sii centres (Randazzo et al., 2006[Randazzo, J. B., Morris, J. J. & Henderson, K. W. (2006). Main Group Chem. 5, 215-220.]), the relative positions of the C3/C3i, C2/C1i and C1/C2i pairs across this vector produce C—Si⋯Sii—Ci torsion angles of −8.846 (11), −2.52 (7) and −2.52 (7)°, respectively (average value −4.63°). These figures are close to the 0° value attributed to the eclipsed conformation (Eliel & Wilen, 1994[Eliel, E. L. & Wilen, S. H. (1994). Stereochemistry of Organic Compounds, p. 1197. Hoboken, NJ: Wiley Interscience.]). Small torsion angles also appear in the amide ligand of [Cs{N(SiMe3)2}(tmeea)] (tmeea = tris­[2-(2-meth­oxy­eth­oxy)eth­yl]amine)], [{K(N{SiMe3}2)(tBu-C6H5)}2], and [{K(N{SiMe3}2)(Me3C6H3)}2], with average values of −3.81 (4), 4.70 and 0.75° respectively (Ojeda-Amador et al., 2016[Ojeda-Amador, A. I., Martínez-Martínez, A. J., Kennedy, A. R. & O'Hara, C. T. (2016). Inorg. Chem. 55, 5719-5728.]; Randazzo et al., 2006[Randazzo, J. B., Morris, J. J. & Henderson, K. W. (2006). Main Group Chem. 5, 215-220.]). A larger deviation from 0° appears in [K(18-crown-6)][Li{N(SiMe3)2}2] (mean torsion angle −11.40°; Davison et al., 2023[Davison, N., Waddell, P. G. & Lu, E. (2023). J. Am. Chem. Soc. 145, 17007-17012.]) and in the polymeric [{(Me3Si)2NLi}{(Me3Si)2NK}]∞ (–11.94°; Morris et al., 2007[Morris, J. J., Noll, B. C. & Henderson, K. W. (2007). Acta Cryst. E63, m2477.]). On the other hand, the methyl groups of unsolvated K(N{SiMe3}2) adopt an inter­mediate mean torsion angle of 38.29° (Tesh et al., 1990[Tesh, K. F., Hanusa, T. P. & Huffman, J. C. (1990). Inorg. Chem. 29, 1584-1586.]), while in [Li{N(SiMe3)2}(Me6Tren)] (Me6Tren = tris­[2-(di­methyl­amino)­eth­yl]amine) the average angle is 59.9°, almost exactly the ideal value of 60° for a staggered conformation (Cousins et al., 2010[Cousins, D. M., Davidson, M. G., Frankis, C. J., García-Vivó, D. & Mahon, M. F. (2010). Dalton Trans. 39, 8278-8280.]). In the present work, eclipsing implies less repulsion between the bulky methyl groups of both the hexa­methyl­disilyl­amide and Phox ligands than in the staggered arrangement.

[Figure 3]
Figure 3
Left: Mol­ecular structure of [Li{N(Si(CH3)3)2}(Phox)2], showing the eclipsed conformation of the hexa­methyl­disilyl­amide ligands. Hydrogen atoms are omitted for clarity. Displacement ellipsoids are drawn at the 50% probability level. Right: Space-filling representation of the title compound, emphasizing the efficient shielding of the lithium cation by the methyl and phenyl substituents of the HMDS− and Phox ligands.

3. Supra­molecular features

Hirshfeld surface analysis performed with the CrystalExplorer 21.5 software (Spackman et al., 2021[Spackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006-1011.]) allowed a comprehensive examination of the non-covalent bonds governing the solid-state structure of [Li{N(Si(CH3)3)2}(Phox)2]. A pivotal aspect of this analysis involves the generation of 2D fingerprint plots (FP), which offer two-dimensional projections of the Hirshfeld surface (Hirshfeld, 1977[Hirshfeld, F. L. (1977). Theor. Chim. Acta, 44, 129-138.]). This enables meticulous analysis of the non-covalent forces supporting the supra­molecular structure by qu­anti­fying the percentage contribution of each inter­action. For [Li{N(Si(CH3)3)2}(Phox)2], the percentages of the total surface area corres­ponding to the H⋯H, C⋯H, and O⋯H contacts account for 82.2%, 11.5%, and 6.2%, respectively (Fig. 4[link]). The frail O⋯H contacts occur between the hydrogen atoms of the methyl­ene groups in the oxazoline rings and the oxygen atom of the adjacent mol­ecules at 2.843 Å. Besides those, there is only a weak intra­molecular π–π stacking inter­action between the aromatic rings of the Phox ligands, as already depicted in Fig. 2[link], which are 3.908 (5) Å far from one another. There is no classic intra or inter­molecular hydrogen bonding in the mol­ecule.

[Figure 4]
Figure 4
(a) Representation of the Hirshfeld surface for [Li{N(Si(CH3)3)2}(Phox)2], highlighting the inter­molecular O⋯H contacts (green dashed lines) between the oxazoline's methyl­ene moiety and the oxygen atom of the adjacent mol­ecule. Grey: carbon; red: oxygen; blue: nitro­gen; light blue: silicon; purple: lithium. Hydrogen atoms are omitted for clarity. (b) Two-dimensional fingerprint plots in the dnorm function, generated by mapping, for each di, the region between 0.4 and 2.6 Å from the surface to the nearest inter­nal (di) and external (de) atoms.

4. Database survey

To the best of our knowledge, this is the first example of a heteroleptic lithium(I)–oxazoline complex in which the Phox ligands are monodentate and the HMDS anion adopts a nearly eclipsed conformation of the methyl groups, giving rise to a trigonal planar coordination environment about the metal. The combination of ten methyl and two phenyl substituents in the ligands efficiently shields the central ion (Fig. 3[link], right) and prevents significant inter­molecular contacts involving the metal.

5. Synthesis and crystallization

The reactions were carried out under di­nitro­gen (99.999%, Praxair or Air Liquide) using Schlenk techniques. Analytical grade 2-amino-2-methyl-1-propanol, ethyl­eneglycol, potassium carbonate, glycerol, benzo­nitrile, n-butyl lithium (2.5 mol L−1 solution in hexa­nes) and hexa­methyl­disilazane were acquired from commercial sources (Sigma-Aldrich, Merck, Synth) and used without purification. Hexane (Honeywell) was dried by standard methods (Armarego & Perrin, 1997[Armarego, W. L. F. & Perrin, D. D. (1997). Purification of Laboratory Chemicals, 4th ed. United Kingdom: Butterworth-Heinemann.]) and distilled under N2(g) immediately before use. Lithium hexa­methyl­disilyl­amide, LiHMDS (Tai et al., 2017[Tai, O., Hopson, R. & Williard, P. G. (2017). J. Org. Chem. 82, 6223-6231.]), and Phox (Mulahmetovic & Hargaden, 2019[Mulahmetovic, E. & Hargaden, G. C. (2019). Mini-Rev. Org. Chem. 16, 507-526.]) were prepared using procedures adapted from the literature; Phox was distilled twice under vacuum before use. A solution of 0.472 g (2.85 mmol) of LiHMDS in 10 mL of hexane was added slowly to a hexane solution of 0.500 g (2.85 mmol) of Phox at 273 K. The colourless reaction mixture was stirred at room temperature for about 5 h and filtered through Celite. The resulting colourless solution was cooled down to 253 K for two days, after which block-shaped colourless crystals were isolated by filtration and dried under vacuum. Total yield: 0.621g (85.0%) based on the [Li{N(Si(CH3)3)2}(Phox)2] formulation.

6. Refinement

Table 1[link] summarizes crystal data, data collection, and structure refinement details. The hydrogen atoms were located in difference-Fourier maps and were refined freely, except for the hydrogen atoms attached to C1, C6, C7, C11, C14, and C15 atoms, for which distance restraints (DFIX) were applied.

Table 1
Experimental details

Crystal data
Chemical formula [Li(C6H18NSi2)(C11H13NO)2]
Mr 517.78
Crystal system, space group Monoclinic, C2/c
Temperature (K) 100
a, b, c (Å) 15.612 (2), 12.7649 (17), 17.180 (4)
β (°) 116.243 (5)
V (Å3) 3070.9 (9)
Z 4
Radiation type Mo Kα
μ (mm−1) 0.14
Crystal size (mm) 0.50 × 0.44 × 0.28
 
Data collection
Diffractometer Bruker D8 Venture/Photon 100 CMOS
Absorption correction Multi-scan (SADABS; Krause et al., 2015[Krause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3-10.])
Tmin, Tmax 0.709, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections 44358, 3522, 2888
Rint 0.078
(sin θ/λ)max (Å−1) 0.650
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.035, 0.092, 1.04
No. of reflections 3522
No. of parameters 252
No. of restraints 7
H-atom treatment All H-atom parameters refined
Δρmax, Δρmin (e Å−3) 0.29, −0.24
Computer programs: APEX3 and SAINT (Bruker, 2015[Bruker (2015). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]), SHELXS2008 (Sheldrick 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2018/3 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), DIAMOND (Brandenburg & Putz, 1999[Brandenburg, K. & Putz, H. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.]), and Mercury (Macrae et al., 2020[Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226-235.]) and WinGX (Farrugia, 2012[Farrugia, L. J. (2012). J. Appl. Cryst. 45, 849-854.]).

Supporting information

CCDC reference: 2354028

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989024004237/ej2003sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989024004237/ej2003Isup2.hkl

Supporting information file. DOI: https://doi.org/10.1107/S2056989024004237/ej2003Isup3.mol

checkCIF report


Computing details top

Bis(4,4-dimethyl-2-phenyl-2-oxazoline-κN)(hexamethyldisilylamido-κN)lithium top
Crystal data top
[Li(C6H18NSi2)(C11H13NO)2]F(000) = 1120
Mr = 517.78Dx = 1.120 Mg m−3
Monoclinic, C2/cMo Kα radiation, λ = 0.71073 Å
a = 15.612 (2) ÅCell parameters from 9967 reflections
b = 12.7649 (17) Åθ = 2.9–27.7°
c = 17.180 (4) ŵ = 0.14 mm−1
β = 116.243 (5)°T = 100 K
V = 3070.9 (9) Å3Parallelepiped, colourless
Z = 40.50 × 0.44 × 0.28 mm
Data collection top
Bruker D8 Venture/Photon 100 CMOS
diffractometer		3522 independent reflections
Radiation source: fine-focus sealed tube2888 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.078
Detector resolution: 10.4167 pixels mm-1θmax = 27.5°, θmin = 2.9°
φ and ω scansh = −20→20
Absorption correction: multi-scan
(SADABS; Krause et al., 2015)		k = −16→16
Tmin = 0.709, Tmax = 0.746l = −22→22
44358 measured reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.035Hydrogen site location: difference Fourier map
wR(F2) = 0.092All H-atom parameters refined
S = 1.04 w = 1/[σ2(Fo2) + (0.0461P)2 + 1.6645P]
where P = (Fo2 + 2Fc2)/3
3522 reflections(Δ/σ)max = 0.001
252 parametersΔρmax = 0.29 e Å−3
7 restraintsΔρmin = −0.23 e Å−3
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Li0.5000000.4524 (2)0.2500000.0204 (6)
Si0.57050 (2)0.24246 (3)0.21203 (2)0.01863 (10)
N10.5000000.30027 (11)0.2500000.0182 (3)
N20.37995 (7)0.54071 (8)0.16385 (7)0.0192 (2)
O80.28490 (7)0.67752 (8)0.09434 (6)0.0283 (2)
C10.50526 (11)0.15288 (11)0.11638 (9)0.0283 (3)
C20.66991 (11)0.15862 (12)0.29266 (10)0.0317 (3)
C30.62947 (10)0.34286 (12)0.17146 (10)0.0274 (3)
C40.31661 (9)0.50169 (10)0.07406 (8)0.0238 (3)
C50.37382 (13)0.44781 (14)0.03410 (10)0.0391 (4)
C60.24248 (14)0.43000 (18)0.08063 (12)0.0527 (6)
C70.27067 (11)0.60331 (12)0.02589 (9)0.0307 (3)
C90.35350 (8)0.63426 (10)0.16790 (8)0.0194 (3)
C100.38916 (9)0.70370 (10)0.24400 (8)0.0198 (3)
C110.38259 (10)0.81222 (10)0.23259 (9)0.0255 (3)
C120.41867 (11)0.87807 (11)0.30369 (10)0.0313 (3)
C130.46139 (11)0.83697 (12)0.38667 (10)0.0310 (3)
C140.46664 (10)0.72887 (11)0.39881 (9)0.0280 (3)
C150.43035 (9)0.66244 (11)0.32782 (8)0.0226 (3)
H1A0.4564 (12)0.1901 (13)0.0681 (10)0.040 (5)*
H1B0.5497 (14)0.1223 (15)0.0952 (12)0.049 (5)*
H1C0.4750 (13)0.0932 (15)0.1312 (12)0.041 (5)*
H2A0.6467 (14)0.0989 (15)0.3147 (12)0.046 (5)*
H2B0.7134 (16)0.1985 (18)0.3410 (15)0.064 (6)*
H2C0.7052 (15)0.1233 (16)0.2666 (13)0.054 (6)*
H3A0.6706 (14)0.3083 (15)0.1489 (12)0.051 (5)*
H3B0.5826 (14)0.3873 (15)0.1232 (13)0.048 (5)*
H3C0.6702 (15)0.3943 (16)0.2176 (13)0.052 (5)*
H5A0.4240 (14)0.4948 (15)0.0334 (12)0.049 (5)*
H5B0.3314 (14)0.4287 (16)−0.0254 (14)0.054 (6)*
H5C0.4050 (15)0.3855 (17)0.0682 (14)0.058 (6)*
H6A0.2020 (15)0.4040 (16)0.0223 (11)0.064 (6)*
H6B0.2736 (14)0.3696 (14)0.1122 (13)0.060 (6)*
H6C0.204 (2)0.465 (2)0.110 (2)0.101 (10)*
H7A0.3021 (13)0.6319 (14)−0.0113 (12)0.041 (5)*
H7B0.2033 (10)0.5970 (14)−0.0090 (11)0.041 (5)*
H110.3552 (12)0.8399 (12)0.1757 (9)0.033 (4)*
H120.4131 (12)0.9517 (14)0.2954 (11)0.038 (5)*
H130.4891 (13)0.8821 (14)0.4369 (12)0.040 (5)*
H140.4949 (11)0.7004 (12)0.4566 (9)0.030 (4)*
H150.4321 (11)0.5886 (10)0.3360 (10)0.026 (4)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Li0.0169 (14)0.0193 (14)0.0197 (14)0.0000.0033 (11)0.000
Si0.01801 (18)0.01873 (17)0.01628 (17)0.00254 (12)0.00498 (13)−0.00047 (12)
N10.0188 (7)0.0169 (7)0.0171 (7)0.0000.0061 (6)0.000
N20.0158 (5)0.0211 (5)0.0162 (5)−0.0006 (4)0.0028 (4)0.0025 (4)
O80.0283 (5)0.0300 (5)0.0190 (4)0.0125 (4)0.0035 (4)0.0056 (4)
C10.0322 (8)0.0261 (7)0.0221 (7)0.0030 (6)0.0079 (6)−0.0048 (5)
C20.0260 (7)0.0296 (7)0.0302 (8)0.0092 (6)0.0040 (6)0.0017 (6)
C30.0243 (7)0.0325 (7)0.0284 (7)0.0003 (6)0.0146 (6)−0.0001 (6)
C40.0207 (6)0.0236 (6)0.0170 (6)−0.0013 (5)−0.0007 (5)0.0030 (5)
C50.0380 (9)0.0391 (9)0.0242 (7)0.0102 (7)−0.0007 (7)−0.0097 (6)
C60.0419 (10)0.0597 (12)0.0316 (9)−0.0306 (9)−0.0064 (8)0.0109 (8)
C70.0322 (8)0.0314 (7)0.0196 (6)0.0088 (6)0.0034 (6)0.0033 (5)
C90.0143 (6)0.0238 (6)0.0183 (6)0.0030 (5)0.0057 (5)0.0061 (5)
C100.0168 (6)0.0234 (6)0.0208 (6)0.0043 (5)0.0096 (5)0.0028 (5)
C110.0271 (7)0.0250 (7)0.0246 (7)0.0072 (5)0.0116 (6)0.0062 (5)
C120.0388 (8)0.0220 (7)0.0345 (8)0.0056 (6)0.0176 (7)0.0010 (6)
C130.0351 (8)0.0325 (7)0.0277 (7)0.0027 (6)0.0159 (6)−0.0065 (6)
C140.0322 (7)0.0336 (7)0.0204 (6)0.0070 (6)0.0137 (6)0.0024 (5)
C150.0234 (6)0.0240 (6)0.0219 (6)0.0061 (5)0.0116 (5)0.0045 (5)
Geometric parameters (Å, º) top
Li—N11.942 (3)C4—C61.518 (2)
Li—N22.1263 (18)C4—C71.5353 (18)
Li—N2i2.1264 (18)C5—H5A0.99 (2)
Li—Sii3.074 (3)C5—H5B0.97 (2)
Si—N11.6782 (7)C5—H5C0.98 (2)
Si—C31.8824 (15)C6—H6A0.976 (15)
Si—C11.8881 (14)C6—H6B0.945 (15)
Si—C21.8900 (14)C6—H6C1.04 (3)
N2—C91.2756 (16)C7—H7A1.029 (19)
N2—C41.5022 (16)C7—H7B0.956 (14)
O8—C91.3610 (15)C9—C101.4700 (18)
O8—C71.4486 (17)C10—C151.3950 (18)
C1—H1A0.968 (14)C10—C111.3964 (18)
C1—H1B1.00 (2)C11—C121.381 (2)
C1—H1C0.988 (19)C11—H110.944 (13)
C2—H2A0.99 (2)C12—C131.383 (2)
C2—H2B0.95 (2)C12—H120.949 (18)
C2—H2C0.96 (2)C13—C141.392 (2)
C3—H3A0.99 (2)C13—H130.967 (18)
C3—H3B1.00 (2)C14—C151.3843 (19)
C3—H3C1.01 (2)C14—H140.963 (13)
C4—C51.511 (2)C15—H150.952 (13)
N1—Li—N2122.02 (7)C5—C4—C7111.64 (12)
N1—Li—N2i122.02 (7)C6—C4—C7111.07 (14)
N2—Li—N2i115.95 (14)C4—C5—H5A111.0 (11)
N1—Li—Sii29.36 (3)C4—C5—H5B109.1 (12)
N2—Li—Sii108.77 (5)H5A—C5—H5B108.4 (16)
N2i—Li—Sii127.05 (6)C4—C5—H5C109.6 (12)
N1—Si—C3110.90 (7)H5A—C5—H5C108.2 (16)
N1—Si—C1114.23 (6)H5B—C5—H5C110.6 (16)
C3—Si—C1104.72 (7)C4—C6—H6A107.3 (13)
N1—Si—C2115.55 (6)C4—C6—H6B108.6 (13)
C3—Si—C2106.22 (7)H6A—C6—H6B104.3 (17)
C1—Si—C2104.31 (7)C4—C6—H6C113.5 (16)
Si—N1—Sii127.83 (9)H6A—C6—H6C113 (2)
Si—N1—Li116.09 (4)H6B—C6—H6C109 (2)
Sii—N1—Li116.09 (4)O8—C7—C4104.34 (10)
C9—N2—C4106.52 (10)O8—C7—H7A109.1 (10)
C9—N2—Li131.72 (11)C4—C7—H7A113.4 (10)
C4—N2—Li121.09 (9)O8—C7—H7B107.2 (11)
C9—O8—C7105.29 (10)C4—C7—H7B112.9 (11)
Si—C1—H1A111.5 (11)H7A—C7—H7B109.6 (15)
Si—C1—H1B111.1 (11)N2—C9—O8118.04 (11)
H1A—C1—H1B107.0 (15)N2—C9—C10127.49 (11)
Si—C1—H1C112.2 (10)O8—C9—C10114.47 (11)
H1A—C1—H1C108.4 (15)C15—C10—C11119.42 (12)
H1B—C1—H1C106.4 (15)C15—C10—C9120.72 (11)
Si—C2—H2A113.3 (11)C11—C10—C9119.86 (11)
Si—C2—H2B111.9 (13)C12—C11—C10120.24 (13)
H2A—C2—H2B108.5 (17)C12—C11—H11120.5 (10)
Si—C2—H2C112.2 (12)C10—C11—H11119.2 (10)
H2A—C2—H2C101.5 (16)C11—C12—C13120.21 (13)
H2B—C2—H2C108.8 (18)C11—C12—H12119.8 (11)
Si—C3—H3A110.5 (11)C13—C12—H12120.0 (11)
Si—C3—H3B113.2 (11)C12—C13—C14120.00 (14)
H3A—C3—H3B106.9 (15)C12—C13—H13121.0 (11)
Si—C3—H3C113.2 (11)C14—C13—H13118.9 (11)
H3A—C3—H3C107.8 (16)C15—C14—C13120.07 (13)
H3B—C3—H3C104.9 (15)C15—C14—H14120.0 (10)
N2—C4—C5111.37 (11)C13—C14—H14119.9 (10)
N2—C4—C6107.51 (12)C14—C15—C10120.03 (12)
C5—C4—C6112.48 (16)C14—C15—H15120.2 (9)
N2—C4—C7102.23 (10)C10—C15—H15119.8 (9)
C3—Si—N1—Sii176.77 (5)Li—N2—C9—O8165.63 (9)
C1—Si—N1—Sii58.73 (6)C4—N2—C9—C10175.66 (12)
C2—Si—N1—Sii−62.30 (6)Li—N2—C9—C10−13.9 (2)
C3—Si—N1—Li−3.23 (5)C7—O8—C9—N2−7.87 (16)
C1—Si—N1—Li−121.27 (6)C7—O8—C9—C10171.71 (11)
C2—Si—N1—Li117.70 (6)N2—C9—C10—C15−24.5 (2)
C9—N2—C4—C5133.79 (13)O8—C9—C10—C15155.95 (12)
Li—N2—C4—C5−37.89 (15)N2—C9—C10—C11154.97 (13)
C9—N2—C4—C6−102.56 (15)O8—C9—C10—C11−24.56 (17)
Li—N2—C4—C685.76 (15)C15—C10—C11—C121.6 (2)
C9—N2—C4—C714.45 (14)C9—C10—C11—C12−177.93 (13)
Li—N2—C4—C7−157.23 (10)C10—C11—C12—C13−0.1 (2)
C9—O8—C7—C416.31 (14)C11—C12—C13—C14−1.1 (2)
N2—C4—C7—O8−18.50 (14)C12—C13—C14—C150.9 (2)
C5—C4—C7—O8−137.66 (13)C13—C14—C15—C100.5 (2)
C6—C4—C7—O895.91 (15)C11—C10—C15—C14−1.77 (19)
C4—N2—C9—O8−4.81 (15)C9—C10—C15—C14177.72 (12)
Symmetry code: (i) −x+1, y, −z+1/2.
 

Acknowledgements

JSCN, EMI, FSS, and JFS thank the Brazilian research agencies Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant 314581/2020–0) and Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (Capes, Financial Code 001) for scholarships and financial support.

Funding information

Funding for this research was provided by: Conselho Nacional de Desenvolvimento Científico e Tecnológico (grant No. 314581/2020-0); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (grant No. 0347/2021).

References

First citationAbu-Elfotoh, A. M. (2017). Tetrahedron Lett. 58, 4750–4754.  CAS Google Scholar
 First citationArmarego, W. L. F. & Perrin, D. D. (1997). Purification of Laboratory Chemicals, 4th ed. United Kingdom: Butterworth–Heinemann.  Google Scholar
 First citationBagherzadeh, M., Latifi, R., Tahsini, L. & Amini, M. (2008). Catal. Commun. 10, 196–200.  Web of Science CrossRef CAS Google Scholar
 First citationBarclay, T. M., del Río, I., Gossage, R. A. & Jackson, S. M. (2003). Can. J. Chem. 81, 1482–1491.  Web of Science CSD CrossRef CAS Google Scholar
 First citationBeak, P., Basu, A., Gallagher, D. J., Park, Y. S. & Thayumanavan, S. (1996). Acc. Chem. Res. 29, 552–560.  CrossRef CAS Web of Science Google Scholar
 First citationBottini, R. C. R., Gariani, R. A., Cavalcanti, C. O., de Oliveira, F., da Rocha, N. L. G., Back, D., Lang, E. S., Hitchcock, P. B., Evans, D. J., Nunes, G. G., Simonelli, F., de Sá, E. L. & Soares, J. F. (2010). Eur. J. Inorg. Chem. 2010, 2476–2487.  Web of Science CSD CrossRef Google Scholar
 First citationBrandenburg, K. & Putz, H. (1999). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationBruker (2015). APEX3 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationClark, N. M., García-Álvarez, P., Kennedy, A. R., O'Hara, C. T. & Robertson, G. M. (2009). Chem. Commun. pp. 5835–5837.  Web of Science CSD CrossRef Google Scholar
 First citationConnon, R., Roche, B., Rokade, B. V. & Guiry, P. J. (2021). Chem. Rev. 121, 6373–6521.  Web of Science CrossRef CAS PubMed Google Scholar
 First citationCousins, D. M., Davidson, M. G., Frankis, C. J., García-Vivó, D. & Mahon, M. F. (2010). Dalton Trans. 39, 8278–8280.  Web of Science CSD CrossRef CAS PubMed Google Scholar
 First citationDavison, N., Waddell, P. G. & Lu, E. (2023). J. Am. Chem. Soc. 145, 17007–17012.  Web of Science CSD CrossRef CAS PubMed Google Scholar
 First citationEliel, E. L. & Wilen, S. H. (1994). Stereochemistry of Organic Compounds, p. 1197. Hoboken, NJ: Wiley Interscience.  Google Scholar
 First citationFarrugia, L. J. (2012). J. Appl. Cryst. 45, 849–854.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationFjeldberg, T., Hitchcock, P. B., Lappert, M. F. & Thorne, A. J. (1984). J. Chem. Soc. Chem. Commun. pp. 822–824.  CSD CrossRef Web of Science Google Scholar
 First citationGómez, M., Muller, G. & Rocamora, M. (1999). Coord. Chem. Rev. 193–195, 769–835.  Google Scholar
 First citationGregory, K. P., Schleyer, P., v, R. & Snaith, R. (1991). Adv. Inorg. Chem. 37, 47–142.  CrossRef CAS Web of Science Google Scholar
 First citationHenderson, K. W., Dorigo, A. E., Liu, Q.-L. & Williard, P. G. (1997). J. Am. Chem. Soc. 119, 49, 11855–11863.  Google Scholar
 First citationHirshfeld, F. L. (1977). Theor. Chim. Acta, 44, 129–138.  CrossRef CAS Web of Science Google Scholar
 First citationHuang, P., Wang, Y. X., Yu, H. F. & Lu, J. M. (2014). Organometallics, 33, 1587–1593.  Web of Science CSD CrossRef CAS Google Scholar
 First citationJantzi, K. L., Guzei, I. A. & Reich, H. J. (2006). Organometallics, 25, 5390–5395.  Web of Science CSD CrossRef CAS Google Scholar
 First citationKandasamy, K., Singh, H. B., Butcher, R. J. & Jasinski, J. P. (2004). Inorg. Chem. 43, 5704–5713.  Web of Science CSD CrossRef PubMed CAS Google Scholar
 First citationKrause, L., Herbst-Irmer, R., Sheldrick, G. M. & Stalke, D. (2015). J. Appl. Cryst. 48, 3–10.  Web of Science CSD CrossRef ICSD CAS IUCr Journals Google Scholar
 First citationLiu, X., Chen, P. & Wu, F. (2016). Chin. J. Org. Chem. 36, 1797–1804.  Web of Science CrossRef CAS Google Scholar
 First citationMacrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226–235.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationMcManus, H. A. & Guiry, P. J. (2004). Chem. Rev. 104, 4151–4202.  Web of Science CrossRef PubMed CAS Google Scholar
 First citationMichelin, R. A., Bertani, R., Mozzon, M., Bombieri, G., Benetollo, F. & Angelici, R. J. (1991). Organometallics, 10, 1751–1757.  CSD CrossRef CAS Web of Science Google Scholar
 First citationMohamed, A. H. (2010). Coord. Chem. Rev. 254, 1918–1947.  Web of Science CrossRef CAS Google Scholar
 First citationMootz, D., Zinnius, A. & Böttcher, B. (1969). Angew. Chem. 81, 398–399.  CrossRef Google Scholar
 First citationMorris, J. J., Noll, B. C. & Henderson, K. W. (2007). Acta Cryst. E63, m2477.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationMulahmetovic, E. & Hargaden, G. C. (2019). Mini-Rev. Org. Chem. 16, 507–526.  Web of Science CrossRef CAS Google Scholar
 First citationNeufeld, R., Michel, R., Herbst–Irmer, R., Schöne, R. & Stalke, D. (2016). Chem. A Eur. J. 22, 12340–12346.  Web of Science CSD CrossRef CAS Google Scholar
 First citationOjeda-Amador, A. I., Martínez-Martínez, A. J., Kennedy, A. R. & O'Hara, C. T. (2016). Inorg. Chem. 55, 5719–5728.  Web of Science CAS PubMed Google Scholar
 First citationPower, P. P. (2004). J. Organomet. Chem. 689, 3904–3919.  Web of Science CrossRef CAS Google Scholar
 First citationRandazzo, J. B., Morris, J. J. & Henderson, K. W. (2006). Main Group Chem. 5, 215–220.  Web of Science CSD CrossRef CAS Google Scholar
 First citationRasappan, R., Laventine, D. & Reiser, O. (2008). Coord. Chem. Rev. 252, 702–714.  Web of Science CrossRef CAS Google Scholar
 First citationRío, I. del & Gossage, R. A. (2009). Acta Cryst. E65, m103–m104.  Web of Science CSD CrossRef IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationSheldrick, G. M. (2015). Acta Cryst. C71, 3–8.  Web of Science CrossRef IUCr Journals Google Scholar
 First citationSpackman, P. R., Turner, M. J., McKinnon, J. J., Wolff, S. K., Grimwood, D. J., Jayatilaka, D. & Spackman, M. A. (2021). J. Appl. Cryst. 54, 1006–1011.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationStol, M., Snelders, D. J., de Pater, J. J., van Klink, G. P., Kooijman, H., Spek, A. L. & van Koten, G. (2005). Organometallics, 24, 743–749.  Web of Science CSD CrossRef CAS Google Scholar
 First citationTai, O., Hopson, R. & Williard, P. G. (2017). J. Org. Chem. 82, 6223–6231.  Web of Science CSD CrossRef CAS PubMed Google Scholar
 First citationTang, Y., Zakharov, L. N., Rheingold, A. L. & Kemp, R. A. (2005). Polyhedron, 24, 1739–1748.  Web of Science CSD CrossRef CAS Google Scholar
 First citationTesh, K. F., Hanusa, T. P. & Huffman, J. C. (1990). Inorg. Chem. 29, 1584–1586.  CSD CrossRef CAS Web of Science Google Scholar
 First citationValk, J. M., Maassarani, F., van der Sluis, P., Spek, A. L., Boersma, J. & van Koten, G. (1994). Organometallics, 13, 2320–2329.  CSD CrossRef CAS Web of Science Google Scholar
 First citationVolpe, E. C., Manke, D. R., Bartholomew, E. R., Wolczanski, P. T. & Lobkovsky, E. B. (2010). Organometallics, 29, 6642–6652.  Web of Science CSD CrossRef CAS Google Scholar

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ISSN: 2056-9890
Volume 80| Part 6| June 2024| Pages 620-624
https://doi.org/10.1107/S2056989024004237
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