Di­bromido­(N-phenyl­benzamidine-κN′)tin(II)

Ma, X.

doi:10.1107/S2414314617003169

metal-organic compounds

IUCrDATA

ISSN: 2414-3146

Volume 2| Part 2| February 2017| x170316

https://doi.org/10.1107/S2414314617003169

Open

access

Dibromido(N-phenylbenzamidine-κN′)tin(II)

Xiuming Ma ^a ^*

^aInstitute of Applied Chemistry, Shanxi University, Taiyuan 030006, People's Republic of China
^*Correspondence e-mail: 1103148896@qq.com

Edited by O. Blacque, University of Zürich, Switzerland (Received 14 February 2017; accepted 27 February 2017; online 28 February 2017)

The asymmetric unit of the title compound, [SnBr₂(C₁₃H₁₂N₂)], contains an amidine ligand and tin(II) bromide moiety. In the amidine ligand, the phenyl rings present a head-to-tail configuration mode. The tin atom is coordinated by the terminal N atom of the amidine ligand, and the two Br atoms extend to both sides of the Sn atom in a V-shape. The phenyl rings are twisted from the mean N/C/N plane by 26.14 (18) and 79.50 (8)°. The crystal structure features N—H⋯Br hydrogen bonds.

Keywords: crystal structure; stannous bromide; amidinate.

CCDC reference: 1534782

Structure description

The representative amidinate ligand [RC(NR)₂]⁻ is four-electron monoanionic and has a typical conjugated N—C—N construction, through which the negative charge is able to be delocalized so as to form chelating surroundings (Bai et al., 2010 ). Based on this backbone, amidinates have been widely ligated to transition metals (Edelmann, 1994 ), particularly the group 14 metallylenes tin(II). Tin(II) amidinates belong to the family of complexes bearing so-called spectator ligands which are commonly used for fine-tuning of the electronic as well as coordination properties of the metal atom (Chlupatý et al., 2015 ). Interesting features in the title compound arise from the highly catalytic activity in the ring-opening polymerization of caprolactone and aryl isocyanates to perhydro-1,3,5-triazine-2,4,6-triones (isocyanurates) in a living fashion, under mild conditions. As part of our studies in this area, the title compound (Fig. 1) was prepared in a novel manner (reaction in Schlenk bottle by PhNH₂, ⁿBuLi, SiMe₂Cl₂, PhCN, SnCl₂ and Br₂) and we have determined its crystal structure. The compound is closely similar to the benzamidine with an o-tolyl substituent on the N atom, namely N²-o-tolylbenzamidine (Zhang et al., 2008 ), which has no stannous bromine moiety attached.

Figure 1
The molecular structure of the title compound, showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 30% probability level.

The asymmetric unit of the title compound, [SnBr₂(C₁₃H₁₂N₂)], contains an amidine ligand and tin(II) bromide. In the amidine ligand, the phenyl rings exhibit a head-to-tail configuration mode. The tin atom is coordinated by the terminal N atom of the amidine ligand, and the two Br atoms extend to both sides of Sn in a V-shape (Fig. 1). The outward expansion configuration of the two bromine atoms is due to the large steric hindrance of the nearby substituents. The C2–C7 and C8–C13 phenyl rings are twisted from the N1/C1/N2 mean plane by 26.14 (18) and 79.50 (8)°, respectively. The two N atoms connect the central C atom with bond lengths of 1.315 (5) and 1.324 (5) Å, while the Sn—N bond length is 2.176 (3) and the Sn—Br bond lengths are 2.6286 (6) and 2.6313 (6) Å.

In the crystal, the molecules are linked into chains along [100] by N—H⋯Br hydrogen bonds (Fig. 2, Table 1).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯Br1ⁱ	0.88	2.95	3.593 (4)	132
N2—H2⋯Br2ⁱ	0.88	2.77	3.517 (3)	144
Symmetry code: (i) x+1, y, z.

Figure 2
Part of the crystal structure, with hydrogen bonds drawn as dashed lines

Synthesis and crystallization

The title compound was prepared by a reaction of aniline, ⁿBuLi, SiMe₂Cl₂, PhCN, SnCl₂ and Br₂. To a solution of aniline (2.328 g, 5 mmol) in diethyl ether (30 ml) were added ⁿBuLi (2 ml, 2.5 M, 5 mmol) at 273 K and 0.5 equiv. of dimethyl dichlorosilane (0.3 ml, 2.5 mmol) 3 h later; the solution was stirred overnight and filtered to remove the white LiCl precipitate. ⁿBuLi (2 ml, 2.5 M, 5 mmol) was added again, then PhCN (0.5 ml, 5 mmol) was added by syringe in drops 4 h later. After stirring overnight, SnCl₂ (0.474 g, 2.5 mmol) was added at 273 K and the solution was stirred for 12 h. Then the solvent was removed under vacuum followed by extraction with dichloromethane and filtration to remove the white LiCl precipitate. To the filtrate was added Br₂ (0.13 ml, 2.52 mmol) and the solution was concentrated in vacuo to ca 15 ml about 24 h later. Colorless crystals (0.151 g, 76% yield) were obtained in toluene.

¹H NMR (300 MHz, CDCl₃): δ 6.59–7.68 (m, 11H; phenyl, C=N), 11.04 (s, 1H, C—N). ¹³C NMR(75 MHz, CDCl₃): δ 122.03, 124.32, 124.68, 127.68, 128.21, 128.67, 130.08 (phenyls), Elemental analysis (calculated %) for C₁₃H₁₂Br₂N₂Sn: C, 30.81; H, 2.45; N, 6.09%. Found: C, 31.89; H, 2.55; N, 5.90%.

Refinement

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

Table 2
Experimental details

Crystal data
Chemical formula	[SnBr₂(C₁₃H₁₂N₂)]
M_r	474.76
Crystal system, space group	Triclinic, P $[\overline{1}]$
Temperature (K)	200
a, b, c (Å)	8.0315 (11), 9.7147 (14), 10.7577 (15)
α, β, γ (°)	111.205 (4), 90.226 (5), 109.381 (4)
V (Å³)	730.81 (18)
Z	2
Radiation type	Mo Kα
μ (mm⁻¹)	7.20
Crystal size (mm)	0.06 × 0.06 × 0.05

Data collection
Diffractometer	Bruker SMART area-detector
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996 )
T_min, T_max	0.672, 0.715
No. of measured, independent and observed [I > 2σ(I)] reflections	7880, 2558, 2278
R_int	0.023
(sin θ/λ)_max (Å⁻¹)	0.595

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.055, 1.05
No. of reflections	2558
No. of parameters	164
H-atom treatment	H-atom parameters constrained
Δρ_max, Δρ_min (e Å⁻³)	0.64, −0.57
Computer programs: SMART and SAINT (Bruker, 2000 ), SHELXS97 (Sheldrick, 2008 ) and SHELXL2014 (Sheldrick, 2015 ).

Structural data

CCDC reference: 1534782

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2414314617003169/zq4017sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2414314617003169/zq4017Isup2.hkl

checkCIF report

Computing details top

Data collection: SMART (Bruker, 2000); cell refinement: SAINT (Bruker, 2000); data reduction: SAINT (Bruker, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); software used to prepare material for publication: SHELXL2014 (Sheldrick, 2015).

Dibromido(N-phenylbenzamidine-κN')tin(II) top

Crystal data top

[SnBr₂(C₁₃H₁₂N₂)]	Z = 2
M_r = 474.76	F(000) = 448
Triclinic, P1	D_x = 2.157 Mg m⁻³
a = 8.0315 (11) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.7147 (14) Å	Cell parameters from 5984 reflections
c = 10.7577 (15) Å	θ = 2.9–28.3°
α = 111.205 (4)°	µ = 7.20 mm⁻¹
β = 90.226 (5)°	T = 200 K
γ = 109.381 (4)°	Block, colorless
V = 730.81 (18) Å³	0.06 × 0.06 × 0.05 mm

Data collection top

Bruker SMART area-detector diffractometer	2278 reflections with I > 2σ(I)
φ and ω scan	R_int = 0.023
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	θ_max = 25.0°, θ_min = 2.9°
T_min = 0.672, T_max = 0.715	h = −9→9
7880 measured reflections	k = −11→10
2558 independent reflections	l = −12→12

Refinement top

Refinement on F²	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F² > 2σ(F²)] = 0.025	w = 1/[σ²(F_o²) + (0.0169P)² + 1.8927P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.055	(Δ/σ)_max = 0.001
S = 1.05	Δρ_max = 0.64 e Å⁻³
2558 reflections	Δρ_min = −0.57 e Å⁻³
164 parameters	Extinction correction: SHELXL2014 (Sheldrick, 2015), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0035 (4)

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

	x	y	z	U_iso*/U_eq
Sn1	0.48568 (3)	0.62191 (3)	0.83884 (3)	0.02458 (11)
Br1	0.26091 (5)	0.38582 (5)	0.88757 (5)	0.03684 (14)
Br2	0.28771 (6)	0.53282 (5)	0.60875 (4)	0.03595 (13)
N1	0.6254 (4)	0.4638 (4)	0.7385 (3)	0.0280 (8)
H1	0.5592	0.3670	0.6847	0.034*
N2	0.8777 (4)	0.3932 (4)	0.7203 (4)	0.0335 (8)
H2	0.9950	0.4287	0.7302	0.040*
C1	0.7990 (5)	0.4990 (5)	0.7505 (4)	0.0272 (9)
C2	0.9223 (5)	0.6672 (5)	0.7996 (4)	0.0259 (9)
C3	0.8896 (6)	0.7654 (5)	0.7439 (4)	0.0314 (9)
H3	0.7885	0.7267	0.6781	0.038*
C4	1.0049 (6)	0.9195 (5)	0.7847 (4)	0.0347 (10)
H4	0.9844	0.9870	0.7457	0.042*
C5	1.1505 (6)	0.9767 (5)	0.8821 (4)	0.0337 (10)
H5	1.2298	1.0832	0.9096	0.040*
C6	1.1808 (5)	0.8802 (5)	0.9391 (4)	0.0337 (10)
H6	1.2801	0.9206	1.0069	0.040*
C7	1.0680 (5)	0.7248 (5)	0.8987 (4)	0.0294 (9)
H7	1.0893	0.6579	0.9380	0.035*
C8	0.7869 (5)	0.2245 (5)	0.6727 (4)	0.0293 (9)
C9	0.8323 (6)	0.1320 (5)	0.5586 (5)	0.0378 (11)
H9	0.9193	0.1796	0.5124	0.045*
C10	0.7519 (6)	−0.0305 (5)	0.5106 (5)	0.0396 (11)
H10	0.7858	−0.0942	0.4324	0.048*
C11	0.6239 (6)	−0.1008 (5)	0.5743 (5)	0.0368 (11)
H11	0.5689	−0.2126	0.5406	0.044*
C12	0.5753 (6)	−0.0076 (6)	0.6882 (5)	0.0415 (11)
H12	0.4847	−0.0556	0.7318	0.050*
C13	0.6583 (6)	0.1562 (5)	0.7394 (5)	0.0386 (11)
H13	0.6271	0.2202	0.8190	0.046*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Sn1	0.02065 (15)	0.02166 (15)	0.02717 (17)	0.00595 (11)	0.00258 (11)	0.00613 (12)
Br1	0.0261 (2)	0.0444 (3)	0.0472 (3)	0.00800 (19)	0.00491 (19)	0.0299 (2)
Br2	0.0282 (2)	0.0485 (3)	0.0305 (3)	0.0105 (2)	0.00397 (18)	0.0173 (2)
N1	0.0163 (16)	0.0294 (18)	0.033 (2)	0.0086 (14)	−0.0015 (14)	0.0061 (15)
N2	0.0177 (17)	0.0324 (19)	0.050 (2)	0.0091 (15)	0.0042 (15)	0.0151 (17)
C1	0.029 (2)	0.030 (2)	0.022 (2)	0.0103 (17)	0.0048 (17)	0.0093 (17)
C2	0.0183 (19)	0.026 (2)	0.025 (2)	0.0056 (16)	0.0083 (16)	0.0036 (17)
C3	0.028 (2)	0.037 (2)	0.026 (2)	0.0080 (18)	0.0033 (17)	0.0114 (19)
C4	0.045 (3)	0.031 (2)	0.030 (2)	0.013 (2)	0.007 (2)	0.0142 (19)
C5	0.031 (2)	0.025 (2)	0.035 (3)	0.0023 (18)	0.0034 (19)	0.0075 (19)
C6	0.023 (2)	0.032 (2)	0.034 (2)	0.0039 (18)	−0.0029 (18)	0.0048 (19)
C7	0.025 (2)	0.030 (2)	0.038 (3)	0.0141 (17)	0.0087 (18)	0.0144 (19)
C8	0.028 (2)	0.026 (2)	0.034 (2)	0.0109 (17)	−0.0025 (18)	0.0104 (18)
C9	0.030 (2)	0.039 (2)	0.046 (3)	0.013 (2)	0.007 (2)	0.017 (2)
C10	0.040 (3)	0.030 (2)	0.043 (3)	0.017 (2)	0.004 (2)	0.004 (2)
C11	0.035 (2)	0.026 (2)	0.043 (3)	0.0060 (19)	−0.011 (2)	0.011 (2)
C12	0.037 (3)	0.046 (3)	0.049 (3)	0.011 (2)	0.004 (2)	0.030 (2)
C13	0.044 (3)	0.039 (3)	0.037 (3)	0.020 (2)	0.008 (2)	0.015 (2)

Geometric parameters (Å, º) top

Sn1—N1	2.176 (3)	C5—H5	0.9500
Sn1—Br2	2.6286 (6)	C6—C7	1.380 (6)
Sn1—Br1	2.6313 (6)	C6—H6	0.9500
N1—C1	1.315 (5)	C7—H7	0.9500
N1—H1	0.8800	C8—C9	1.367 (6)
N2—C1	1.324 (5)	C8—C13	1.385 (6)
N2—C8	1.441 (5)	C9—C10	1.381 (6)
N2—H2	0.8800	C9—H9	0.9500
C1—C2	1.492 (5)	C10—C11	1.368 (7)
C2—C3	1.384 (6)	C10—H10	0.9500
C2—C7	1.394 (6)	C11—C12	1.381 (7)
C3—C4	1.376 (6)	C11—H11	0.9500
C3—H3	0.9500	C12—C13	1.392 (6)
C4—C5	1.383 (6)	C12—H12	0.9500
C4—H4	0.9500	C13—H13	0.9500
C5—C6	1.371 (6)

N1—Sn1—Br2	89.80 (9)	C5—C6—C7	120.5 (4)
N1—Sn1—Br1	87.49 (9)	C5—C6—H6	119.8
Br2—Sn1—Br1	90.618 (18)	C7—C6—H6	119.8
C1—N1—Sn1	126.3 (3)	C6—C7—C2	119.1 (4)
C1—N1—H1	116.8	C6—C7—H7	120.4
Sn1—N1—H1	116.8	C2—C7—H7	120.4
C1—N2—C8	125.3 (3)	C9—C8—C13	120.3 (4)
C1—N2—H2	117.4	C9—C8—N2	117.8 (4)
C8—N2—H2	117.4	C13—C8—N2	121.9 (4)
N1—C1—N2	124.3 (4)	C8—C9—C10	120.0 (4)
N1—C1—C2	120.4 (4)	C8—C9—H9	120.0
N2—C1—C2	115.2 (3)	C10—C9—H9	120.0
C3—C2—C7	120.4 (4)	C11—C10—C9	120.8 (4)
C3—C2—C1	118.5 (4)	C11—C10—H10	119.6
C7—C2—C1	121.1 (4)	C9—C10—H10	119.6
C4—C3—C2	119.4 (4)	C10—C11—C12	119.4 (4)
C4—C3—H3	120.3	C10—C11—H11	120.3
C2—C3—H3	120.3	C12—C11—H11	120.3
C3—C4—C5	120.4 (4)	C11—C12—C13	120.4 (4)
C3—C4—H4	119.8	C11—C12—H12	119.8
C5—C4—H4	119.8	C13—C12—H12	119.8
C6—C5—C4	120.2 (4)	C8—C13—C12	119.1 (4)
C6—C5—H5	119.9	C8—C13—H13	120.4
C4—C5—H5	119.9	C12—C13—H13	120.4

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···Br1ⁱ	0.88	2.95	3.593 (4)	132
N2—H2···Br2ⁱ	0.88	2.77	3.517 (3)	144

Symmetry code: (i) x+1, y, z.

Funding information

Funding for this research was provided by: National Natural Science Foundation of China (award No. 20702029); Natural Science Foundation of Shanxi Province (award No. 2008011024).

References

Bai, S.-D., Tong, H.-B., Guo, J.-P., Zhou, M.-S., Liu, D.-S. & Yuan, S.-F. (2010). Polyhedron, 29, 262–269. Web of Science CSD CrossRef CAS Google Scholar
Bruker (2000). SMART and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA. Google Scholar
Chlupatý, T., Růžičková, Z., Horáček, M., Alonso, M., De Proft, F., Kampová, H., Brus, J. & Růžička, A. (2015). Organometallics, 34, 606–615. Google Scholar
Edelmann, F. T. (1994). Coord. Chem. Rev. 137, 403–481. CrossRef Web of Science Google Scholar
Sheldrick, G. M. (1996). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2015). Acta Cryst. C71, 3–8. Web of Science CrossRef IUCr Journals Google Scholar
Zhang, L.-Z. & Tong, H.-B. (2008). Acta Cryst. E64, o1276. Web of Science CSD CrossRef IUCr Journals Google Scholar

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.