Tetra­kis(2,4,6-tri­methyl­anilido)tin(IV)

Lämmer, C.; Merzweiler, K.

doi:10.1107/S2414314624004796

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 9| Part 5| May 2024| x240479

https://doi.org/10.1107/S2414314624004796

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Tetrakis(2,4,6-trimethylanilido)tin(IV)

Christian Lämmer ^a and Kurt Merzweiler ^a ^*

^aMartin-Luther-Universität Halle, Naturwissenschaftliche Fakultät II, Institut für Chemie, Germany
^*Correspondence e-mail: kurt.merzweiler@chemie.uni-halle.de

Edited by M. Weil, Vienna University of Technology, Austria (Received 7 May 2024; accepted 22 May 2024; online 31 May 2024)

Transamination of Sn(NMe₂)₄ with H₂NMes (Mes is 2,4,6-trimethylphenyl, C₉H₁₁) led to the formation of the title compound, [Sn(C₉H₁₂N)₄] or Sn(NHMes)₄, which crystallizes in the tetragonal space group P $[\overline{4}]$ 2₁c, with four formula units per unit cell. The molecular structure consists of a central tin(IV) atom, which is surrounded by four NHMes groups. Sn(NHMes)₄ possesses crystallographically imposed $[\overline{4}]$ symmetry. The SnN₄ coordination polyhedron is best described as a compressed bisphenoid.

Keywords: crystal structure; tin; amide.

CCDC reference: 2357316

Structure description

Contrary to homoleptic silicon amides Si(NHR)₄ [e.g. R = methyl (Andersch & Jansen, 1990 ), R = pentafluorophenyl (Jansen et al., 1992 ), R = i-propyl (Engering et al., 2003 )], corresponding tin(IV) compounds have been studied much less. In 1998, Beswick and co-workers reported the crystal structure of [Li₂(THF)₂Sn(NHCy)₆] (Cy = cyclohexyl), which represents a rare example of a homoleptic tin(IV) amide (Beswick et al., 1998 ). In the context of our investigations on polynuclear organotin(IV) nitrogen compounds like [(MeSn)₄(NHPh)₄(NPh)₄] (Lämmer & Merzweiler, 1999 ), we found that Sn(NMe₂)₄ reacts with 2,4,6-trimethylphenyl amine (H₂NMes) to give the title compound, (1) (Fig. 1).

Figure 1
Molecular structure of compound (1) in the crystal. Displacement ellipsoids are drawn at the 50% probability level. H atoms except for the NH group are omitted for clarity. [Symmetry codes: (i) y, −x + 1, −z + 1; (ii) −x + 1, −y + 1, z; (iii) −y + 1, x, −z + 1.]

The crystal structure of (1) consists of discrete Sn(NHMes)₄ molecules without any unusually short intermolecular contacts. The asymmetric unit consists of one tin(IV) atom on Wyckoff position 2a of space group P $[\overline{4}]$ 2₁c with site symmetry $[\overline{4}]$ , and one NHMes unit on a general position. The tin(IV) atom exhibits a distorted tetrahedral (bisphenoidal) coordination (τ₄ = 0.83, with extreme values of 1 for ideal tetrahedral and 0 for ideal square-planar coordination; Yang et al., 2007 ) from four nitrogen atoms with Sn—N distances of 2.033 (2) Å and N—Sn—N angles from 104.22 (5) to 120.6 (1)° (Table 1). Similar Sn—N distances were observed in (Me₃Si)₃CSn(NH^tBu)₃ (2.017–2.028 Å; Janssen et al., 2003 ), (^tBu₂Sn)₃(NH)₃ (2.030 Å; Puff et al., 1989 ) and 2,4,6-^tBu₃-C₆H₂-NHSnMe₃ (2.050 Å; Lichtscheidl et al., 2015 ) that also exhibit four-coordinate tin(IV) atoms. In the case of [Li₂(THF)₂Sn(NHCy)₆], which contains tin(IV) in a distorted octahedral coordination, the Sn—N distances are longer in average and vary from 2.06–2.27 Å (Beswick et al., 1998). Regarding the NHMes group, bond lengths and angles are within the expected ranges. The N atom in (1) displays a slightly pyramidal coordination, as indicated by the sum of bond angles (345.1°).

Table 1
Selected geometric parameters (Å, °)

Sn—N	2.0332 (19)	N—H	0.79 (3)
N—C1	1.422 (3)

N—Sn—Nⁱ	104.22 (5)	C1—N—Sn	122.05 (15)
N—Sn—Nⁱⁱ	120.57 (12)	C1—N—H	114 (2)
Symmetry codes: (i) ; (ii) .

The packing diagram (Fig. 2) indicates that the molecules of (1) are arranged in undulating layers parallel to (001) in the solid state. The NH groups do not participate in hydrogen bridges. This is obviously due to the steric shielding of the bulky mesityl residues.

Figure 2
Crystal structure of compound (1), in a view along [010].

Synthesis and crystallization

All manipulations were carried out under an argon atmosphere. n-Hexane was freshly distilled from lithium aluminium hydride. Sn(NMe₂)₄ was prepared according to the literature (Jones & Lappert, 1965 ).

2.5 g (18.4 mmol) of mesityl amine were added to a solution of 1.36 g (4.61 mmol) of Sn(NMe₂)₄ in 30 ml of n-hexane. The reaction slowly turned pale yellow and a colourless precipitate was formed. After 12 h the reaction mixture was filtered and 300 mg of the product were received. The filtrate was stored at 253 K to give another 0.83 g of yellowish crystals of the title compound. Combined yield: 1.13 g (38%).

¹H NMR (C₆D₆) δ = 6.17 (s, C₆H₂), 3.38 (s, NH), 2.15 (s, p-CH₃), 2.07 (s, o-CH₃) p.p.m. ¹³C NMR (CDCl₃) δ = 142.1, 129.4, 128.7, 127.6, 20.4, 18.6 p.p.m. ¹¹⁹Sn NMR (CDCl₃) δ = −170.5 p.p.m.

Refinement

Crystal data, data collection, and structure refinement details are given in Table 2.

Table 2
Experimental details

Crystal data
Chemical formula	[Sn(C₉H₁₂N)₄]
M_r	655.47
Crystal system, space group	Tetragonal, P $[\overline{4}]$ 2₁c
Temperature (K)	170
a, c (Å)	13.7000 (6), 8.7123 (5)
V (Å³)	1635.21 (17)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	0.81
Crystal size (mm)	0.50 × 0.35 × 0.30

Data collection
Diffractometer	Stoe IPDS 2
Absorption correction	Integration [X-RED32 (Stoe & Cie, 2016 ), by Gaussian integration analogous to Coppens (1970 )]
T_min, T_max	0.735, 0.898
No. of measured, independent and observed [I > 2σ(I)] reflections	30518, 2205, 2049
R_int	0.053
(sin θ/λ)_max (Å⁻¹)	0.686

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.022, 0.057, 1.07
No. of reflections	2205
No. of parameters	100
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.42, −0.21
Absolute structure	Flack x determined using 832 quotients [(I⁺)−(I⁻)]/[(I⁺)+(I⁻)] (Parsons et al., 2013 )
Absolute structure parameter	−0.036 (19)
Computer programs: X-AREA (Stoe & Cie, 2016), SHELXT (Sheldrick, 2015a ), SHELXL (Sheldrick, 2015b ), DIAMOND (Brandenburg, 2019 ) and OLEX2 (Dolomanov et al., 2009 ).

Structural data

CCDC reference: 2357316

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314624004796/wm4214sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314624004796/wm4214Isup2.hkl

checkCIF report

Computing details top

Tetrakis(2,4,6-trimethylanilido)tin(IV) top

Crystal data top

[Sn(C₉H₁₂N)₄]	D_x = 1.331 Mg m⁻³
M_r = 655.47	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P42₁c	Cell parameters from 28663 reflections
a = 13.7000 (6) Å	θ = 29.7–1.5°
c = 8.7123 (5) Å	µ = 0.81 mm⁻¹
V = 1635.21 (17) Å³	T = 170 K
Z = 2	Block, colourless
F(000) = 684	0.50 × 0.35 × 0.30 mm

Data collection top

Stoe IPDS 2 diffractometer	2049 reflections with I > 2σ(I)
rotation scans	R_int = 0.053
Absorption correction: integration [X-Red32 (Stoe & Cie, 2016), by Gaussian integration analogous to Coppens (1970)]	θ_max = 29.2°, θ_min = 2.1°
T_min = 0.735, T_max = 0.898	h = −18→18
30518 measured reflections	k = −18→17
2205 independent reflections	l = −11→11

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.022	w = 1/[σ²(F_o²) + (0.0329P)² + 0.2402P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.057	(Δ/σ)_max < 0.001
S = 1.07	Δρ_max = 0.42 e Å⁻³
2205 reflections	Δρ_min = −0.21 e Å⁻³
100 parameters	Absolute structure: Flack x determined using 832 quotients [(I⁺)-(I^-)]/[(I⁺)+(I^-)] (Parsons et al., 2013)
0 restraints	Absolute structure parameter: −0.036 (19)

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.

Refinement. The amino hydrogen atom was located from a difference-Fourier map and was refined freely.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Sn	0.500000	0.500000	0.500000	0.03205 (9)
N	0.38602 (14)	0.43981 (15)	0.3843 (2)	0.0398 (4)
H	0.337 (2)	0.464 (2)	0.414 (3)	0.058 (9)*
C9	0.51845 (19)	0.3557 (2)	0.1674 (3)	0.0523 (6)
H9A	0.485199	0.412240	0.122563	0.078*
H9B	0.547813	0.316490	0.085463	0.078*
H9C	0.569620	0.378157	0.237652	0.078*
C6	0.44600 (16)	0.29472 (16)	0.2542 (3)	0.0419 (4)
C5	0.44012 (18)	0.19474 (18)	0.2270 (3)	0.0479 (5)
H5	0.487138	0.165100	0.161838	0.057*
C4	0.36777 (19)	0.13675 (17)	0.2921 (3)	0.0508 (6)
C1	0.37965 (16)	0.33771 (16)	0.3564 (3)	0.0368 (4)
C8	0.3612 (3)	0.0293 (2)	0.2557 (5)	0.0782 (10)
H8A	0.406218	−0.007008	0.321874	0.117*
H8B	0.378659	0.018516	0.147944	0.117*
H8C	0.294318	0.006481	0.273615	0.117*
C3	0.30148 (17)	0.18170 (18)	0.3885 (3)	0.0478 (5)
H3	0.250913	0.143525	0.432859	0.057*
C2	0.30595 (18)	0.28038 (19)	0.4231 (3)	0.0407 (5)
C7	0.23079 (19)	0.3233 (2)	0.5301 (3)	0.0512 (6)
H7A	0.185274	0.363947	0.471476	0.077*
H7B	0.263505	0.363313	0.607882	0.077*
H7C	0.194779	0.270463	0.580599	0.077*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sn	0.02775 (10)	0.02775 (10)	0.04063 (14)	0.000	0.000	0.000
N	0.0305 (9)	0.0343 (9)	0.0544 (11)	−0.0004 (7)	−0.0056 (8)	−0.0023 (8)
C9	0.0519 (14)	0.0485 (13)	0.0566 (13)	−0.0059 (10)	0.0118 (11)	−0.0064 (11)
C6	0.0410 (11)	0.0387 (10)	0.0461 (11)	−0.0019 (8)	−0.0044 (9)	−0.0037 (9)
C5	0.0462 (12)	0.0426 (11)	0.0548 (13)	−0.0015 (10)	−0.0049 (11)	−0.0089 (10)
C4	0.0508 (14)	0.0347 (11)	0.0668 (15)	−0.0026 (9)	−0.0158 (12)	−0.0035 (10)
C1	0.0334 (10)	0.0331 (10)	0.0440 (11)	−0.0022 (8)	−0.0081 (9)	0.0005 (8)
C8	0.074 (2)	0.0391 (13)	0.121 (3)	−0.0126 (13)	−0.007 (2)	−0.0154 (17)
C3	0.0429 (12)	0.0410 (11)	0.0596 (14)	−0.0117 (10)	−0.0119 (11)	0.0084 (11)
C2	0.0362 (11)	0.0399 (12)	0.0459 (13)	−0.0038 (9)	−0.0091 (10)	0.0047 (10)
C7	0.0431 (11)	0.0516 (13)	0.0591 (16)	−0.0067 (10)	0.0046 (10)	0.0035 (11)

Geometric parameters (Å, º) top

Sn—N	2.0332 (19)	C5—H5	0.9500
Sn—Nⁱ	2.0332 (19)	C4—C3	1.382 (4)
Sn—Nⁱⁱ	2.0332 (19)	C4—C8	1.509 (3)
Sn—Nⁱⁱⁱ	2.0332 (19)	C1—C2	1.405 (3)
N—C1	1.422 (3)	C8—H8A	0.9800
N—H	0.79 (3)	C8—H8B	0.9800
C9—C6	1.502 (3)	C8—H8C	0.9800
C9—H9A	0.9800	C3—C2	1.386 (3)
C9—H9B	0.9800	C3—H3	0.9500
C9—H9C	0.9800	C2—C7	1.509 (4)
C6—C5	1.392 (3)	C7—H7A	0.9800
C6—C1	1.402 (3)	C7—H7B	0.9800
C5—C4	1.391 (4)	C7—H7C	0.9800

N—Sn—Nⁱ	104.22 (5)	C5—C4—C8	121.0 (3)
N—Sn—Nⁱⁱ	120.57 (12)	C6—C1—C2	119.6 (2)
Nⁱ—Sn—Nⁱⁱ	104.22 (5)	C6—C1—N	118.8 (2)
N—Sn—Nⁱⁱⁱ	104.22 (5)	C2—C1—N	121.6 (2)
Nⁱ—Sn—Nⁱⁱⁱ	120.57 (12)	C4—C8—H8A	109.5
Nⁱⁱ—Sn—Nⁱⁱⁱ	104.22 (5)	C4—C8—H8B	109.5
C1—N—Sn	122.05 (15)	H8A—C8—H8B	109.5
C1—N—H	114 (2)	C4—C8—H8C	109.5
Sn—N—H	109 (2)	H8A—C8—H8C	109.5
C6—C9—H9A	109.5	H8B—C8—H8C	109.5
C6—C9—H9B	109.5	C4—C3—C2	122.5 (2)
H9A—C9—H9B	109.5	C4—C3—H3	118.7
C6—C9—H9C	109.5	C2—C3—H3	118.7
H9A—C9—H9C	109.5	C3—C2—C1	119.2 (2)
H9B—C9—H9C	109.5	C3—C2—C7	118.9 (2)
C5—C6—C1	118.9 (2)	C1—C2—C7	121.9 (2)
C5—C6—C9	120.0 (2)	C2—C7—H7A	109.5
C1—C6—C9	121.0 (2)	C2—C7—H7B	109.5
C4—C5—C6	122.3 (2)	H7A—C7—H7B	109.5
C4—C5—H5	118.9	C2—C7—H7C	109.5
C6—C5—H5	118.9	H7A—C7—H7C	109.5
C3—C4—C5	117.5 (2)	H7B—C7—H7C	109.5
C3—C4—C8	121.5 (3)

C1—C6—C5—C4	3.2 (4)	Sn—N—C1—C2	114.2 (2)
C9—C6—C5—C4	−173.1 (2)	C5—C4—C3—C2	−1.0 (4)
C6—C5—C4—C3	−1.1 (4)	C8—C4—C3—C2	−179.7 (3)
C6—C5—C4—C8	177.7 (3)	C4—C3—C2—C1	0.9 (4)
C5—C6—C1—C2	−3.2 (3)	C4—C3—C2—C7	−179.7 (2)
C9—C6—C1—C2	173.1 (2)	C6—C1—C2—C3	1.2 (3)
C5—C6—C1—N	179.8 (2)	N—C1—C2—C3	178.2 (2)
C9—C6—C1—N	−3.9 (3)	C6—C1—C2—C7	−178.2 (2)
Sn—N—C1—C6	−68.8 (3)	N—C1—C2—C7	−1.2 (4)

Symmetry codes: (i) y, −x+1, −z+1; (ii) −x+1, −y+1, z; (iii) −y+1, x, −z+1.

Acknowledgements

We thank the Deutsche Forschungsgemeinschaft (DFG) and the Fonds der Chemischen Industrie for financial support. We acknowledge the financial support of the Open Access Publication Fund of the Martin-Luther-University Halle-Wittenberg. A. Kiowski is thanked for his technical support.

Funding information

Funding for this research was provided by: Deutsche Forschungsgemeinschaft; Fonds der Chemischen Industrie.

References

Andersch, H. & Jansen, M. (1990). Acta Cryst. C46, 1180–1181. CrossRef CAS IUCr Journals Google Scholar
Beswick, M. A., Harmer, C. N., Mosquera, M. E. G., Raithby, P. R., Tombul, M., Wright, D. S., Beswick, M. A., Choi, N. & McPartlin, M. (1998). Chem. Commun. pp. 1383–1384. CrossRef Google Scholar
Brandenburg, K. (2019). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Coppens, P. (1970). The Evaluation of Absorption and Extinction in Single-Crystal Structure Analysis. In Crystallographic Computing edited by F. R. Ahmed, pp. 255–270. Copenhagen: Munksgaard. Google Scholar
Dolomanov, O. V., Bourhis, L. J., Gildea, R. J., Howard, J. A. K. & Puschmann, H. (2009). J. Appl. Cryst. 42, 339–341. Web of Science CrossRef CAS IUCr Journals Google Scholar
Engering, J., Nuss, J. & Jansen, M. (2003). Z. Kristallogr. New Cryst. Struct. 218, 201–202. CrossRef CAS Google Scholar
Jansen, M., Rings, S. & Baldus, H. P. (1992). Z. Anorg. Allge Chem. 610, 99–102. CrossRef CAS Google Scholar
Janssen, J., Schmidt, H.-G., Noltemeyer, M. & Roesky, H. W. (2003). Eur. J. Inorg. Chem. pp. 4338–4340. CrossRef Google Scholar
Jones, K. & Lappert, M. F. (1965). J. Chem. Soc. pp. 1944–1951. CrossRef Google Scholar
Lämmer, C. & Merzweiler, K. (1999). Z. Anorg. Allg. Chem. 625, 735–738. Google Scholar
Lichtscheidl, A. G., Janicke, M. T., Scott, B. L., Nelson, A. T. & Kiplinger, J. L. (2015). Dalton Trans. 44, 16156–16163. CrossRef CAS PubMed Google Scholar
Parsons, S., Flack, H. D. & Wagner, T. (2013). Acta Cryst. B69, 249–259. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Puff, H., Hänssgen, D., Beckermann, N., Roloff, A. & Schuh, W. (1989). J. Organomet. Chem. 373, 37–47. CrossRef CAS Google Scholar
Sheldrick, G. M. (2015a). Acta Cryst. A71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Sheldrick, G. M. (2015b). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Stoe & Cie (2016). X-AREA and X-RED32. Stoe & Cie, Darmstadt, Germany. Google Scholar
Yang, L., Powell, D. R. & Houser, R. P. (2007). Dalton Trans. pp. 955–964. Web of Science CSD CrossRef PubMed CAS Google Scholar