Crystal structure of 2-bromo-3-di-methyl-amino-N,N,N',N',4-penta-methyl-4-(tri-methyl-sil-yloxy)pent-2-eneamidinium bromide.

The reaction of the ortho-amide 1,1,1-tris-(di-methyl-amino)-4-methyl-4-(tri-methyl-sil-yloxy)pent-2-yne with bromine in benzene, yields the title salt, C15H33BrN3OSi(+)·Br(-). The C-N bond lengths in the amidinium unit are 1.319 (6) and 1.333 (6) Å, indicating double-bond character, pointing towards charge delocalization within the NCN plane. The C-Br bond length of 1.926 (5) Å is characteristic for a C-Br single bond. Additionally, there is a bromine-bromine inter-action [3.229 (3) Å] present involving the anion and cation. In the crystal, weak C-H⋯Br inter-actions between the methyl H atoms of the cation and the bromide ions are present.

Related literature

For the nature of halogen–halogen inter­actions in crystals, see: Desiraju & Parthasarathy (1989 ▸). For the synthesis of alkynyl ortho­amides and propiolamidinium salts, see: Weingärtner et al. (2011 ▸). For the synthesis of vinyl­ogous guanidinium iodides and bromides, see: Kantlehner et al. (2012a ▸). For the crystal structure of 3-phenyl-N,N,N′,N′′-tetra­methyl-1-ethyne-1-carboximidamidium bromide, see: Tiritiris & Kantlehner (2012b ▸).

Experimental

Crystal data

C15H33BrN3OSi+·Br−

M = 459.33

Orthorhombic,

a = 13.3524 (5) Å

b = 11.3802 (3) Å

c = 27.4261 (14) Å

V = 4167.5 (3) Å3

Z = 8

Mo Kα radiation

μ = 3.95 mm−1

T = 100 K

0.45 × 0.30 × 0.15 mm

Data collection

Bruker Kappa APEXII DUO diffractometer

Absorption correction: multi-scan (Blessing, 1995 ▸) T min = 0.285, T max = 0.530

32287 measured reflections

5164 independent reflections

3394 reflections with I > 2σ(I)

R int = 0.095

Refinement

R[F 2 > 2σ(F 2)] = 0.061

wR(F 2) = 0.099

S = 1.17

5164 reflections

210 parameters

H-atom parameters constrained

Δρmax = 1.10 e Å−3

Δρmin = −1.88 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: SHELXL2014 (Sheldrick, 2015 ▸); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▸); software used to prepare material for publication: SHELXL2014.

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S205698901502383X/ff2146sup1.cif

Click here for additional data file.

. DOI: 10.1107/S205698901502383X/ff2146fig1.tif

The structure of the title compound with displacement ellipsoids at the 50% probability level. All hydrogen atoms were omitted for the sake of clarity. The Br⋯Br inter­action is indicated by a black dashed line.

Click here for additional data file.

. DOI: 10.1107/S205698901502383X/ff2146fig2.tif

C—H⋯Br inter­actions (black dashed lines) between the hydrogen atoms of the methyl groups and the bromide ions. Br⋯Br inter­actions are also indicated by black dashed lines.

CCDC reference: 1441961

Additional supporting information: crystallographic information; 3D view; checkCIF report

C15H33BrN3OSi+·Br−	Dx = 1.464 Mg m−3
Mr = 459.33	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbca	Cell parameters from 32287 reflections
a = 13.3524 (5) Å	θ = 1.5–28.3°
b = 11.3802 (3) Å	µ = 3.95 mm−1
c = 27.4261 (14) Å	T = 100 K
V = 4167.5 (3) Å3	Block, yellow
Z = 8	0.45 × 0.30 × 0.15 mm
F(000) = 1888

Bruker Kappa APEXII DUO diffractometer	5164 independent reflections
Radiation source: fine-focus sealed tube	3394 reflections with I > 2σ(I)
Triumph monochromator	Rint = 0.095
φ scans, and ω scans	θmax = 28.3°, θmin = 1.5°
Absorption correction: multi-scan (Blessing, 1995)	h = −17→10
Tmin = 0.285, Tmax = 0.530	k = −15→15
32287 measured reflections	l = −36→36

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.061	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.099	H-atom parameters constrained
S = 1.17	w = 1/[σ2(Fo2) + 19.9082P] where P = (Fo2 + 2Fc2)/3
5164 reflections	(Δ/σ)max < 0.001
210 parameters	Δρmax = 1.10 e Å−3
0 restraints	Δρmin = −1.88 e Å−3

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

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
Br1	0.54519 (4)	0.73694 (4)	0.13843 (2)	0.01487 (12)
Br2	0.45103 (4)	0.23306 (5)	0.24383 (2)	0.01507 (12)
N1	0.5406 (3)	0.3518 (3)	0.13946 (16)	0.0147 (9)
C1	0.4511 (4)	0.4276 (4)	0.1374 (2)	0.0213 (12)
H1A	0.3938	0.3816	0.1258	0.032*
H1B	0.4633	0.4930	0.1149	0.032*
H1C	0.4367	0.4585	0.1700	0.032*
C2	0.6368 (4)	0.4157 (5)	0.1374 (2)	0.0226 (13)
H2A	0.6879	0.3714	0.1553	0.034*
H2B	0.6287	0.4935	0.1521	0.034*
H2C	0.6576	0.4244	0.1033	0.034*
N2	0.6052 (3)	0.1612 (4)	0.14393 (15)	0.0125 (9)
C3	0.6869 (4)	0.1740 (5)	0.1081 (2)	0.0183 (12)
H3A	0.6711	0.2385	0.0857	0.027*
H3B	0.6942	0.1008	0.0896	0.027*
H3C	0.7496	0.1914	0.1252	0.027*
C4	0.6060 (4)	0.0462 (5)	0.1683 (2)	0.0194 (12)
H4A	0.5545	0.0448	0.1938	0.029*
H4B	0.6719	0.0328	0.1831	0.029*
H4C	0.5922	−0.0157	0.1444	0.029*
C5	0.5318 (3)	0.2392 (4)	0.15005 (16)	0.0109 (10)
C6	0.4400 (4)	0.1967 (4)	0.17545 (17)	0.0113 (10)
C7	0.3621 (3)	0.1384 (4)	0.15758 (18)	0.0090 (10)
N3	0.2856 (3)	0.0847 (4)	0.18667 (15)	0.0135 (10)
C8	0.2094 (4)	0.1616 (5)	0.2075 (2)	0.0202 (13)
H8A	0.2364	0.2005	0.2365	0.030*
H8B	0.1506	0.1149	0.2166	0.030*
H8C	0.1900	0.2209	0.1834	0.030*
C9	0.3192 (4)	−0.0079 (5)	0.2199 (2)	0.0206 (13)
H9A	0.3710	−0.0551	0.2039	0.031*
H9B	0.2623	−0.0583	0.2284	0.031*
H9C	0.3466	0.0277	0.2496	0.031*
C10	0.3455 (4)	0.1153 (4)	0.10276 (18)	0.0087 (10)
C11	0.3601 (4)	−0.0161 (4)	0.09338 (19)	0.0145 (11)
H11A	0.3426	−0.0341	0.0595	0.022*
H11B	0.3168	−0.0612	0.1154	0.022*
H11C	0.4302	−0.0372	0.0993	0.022*
C12	0.2409 (3)	0.1539 (4)	0.08853 (18)	0.0112 (10)
H12A	0.2334	0.2383	0.0947	0.017*
H12B	0.1916	0.1103	0.1078	0.017*
H12C	0.2301	0.1381	0.0538	0.017*
O1	0.4196 (2)	0.1804 (3)	0.07547 (12)	0.0096 (7)
Si1	0.41809 (10)	0.21877 (12)	0.01674 (5)	0.0103 (3)
C13	0.3405 (4)	0.3517 (5)	0.0054 (2)	0.0169 (12)
H13A	0.2698	0.3332	0.0113	0.025*
H13B	0.3491	0.3772	−0.0285	0.025*
H13C	0.3616	0.4149	0.0274	0.025*
C14	0.3757 (4)	0.0988 (5)	−0.02454 (19)	0.0170 (12)
H14A	0.4182	0.0295	−0.0198	0.025*
H14B	0.3804	0.1251	−0.0585	0.025*
H14C	0.3060	0.0785	−0.0170	0.025*
C15	0.5486 (4)	0.2599 (5)	0.00131 (18)	0.0196 (11)
H15A	0.5687	0.3283	0.0207	0.029*
H15B	0.5529	0.2791	−0.0335	0.029*
H15C	0.5934	0.1939	0.0086	0.029*

	U11	U22	U33	U12	U13	U23
Br1	0.0172 (2)	0.0146 (3)	0.0128 (3)	−0.0002 (2)	0.0014 (2)	0.0024 (2)
Br2	0.0157 (2)	0.0198 (3)	0.0097 (2)	0.0007 (2)	−0.0020 (2)	−0.0043 (2)
N1	0.010 (2)	0.015 (2)	0.019 (2)	−0.0006 (18)	−0.003 (2)	−0.0009 (18)
C1	0.017 (3)	0.014 (3)	0.033 (3)	0.006 (2)	−0.003 (3)	−0.002 (2)
C2	0.013 (3)	0.018 (3)	0.036 (4)	−0.009 (2)	−0.004 (3)	−0.003 (3)
N2	0.009 (2)	0.013 (2)	0.015 (2)	0.0023 (16)	−0.0033 (18)	−0.0027 (18)
C3	0.011 (3)	0.024 (3)	0.020 (3)	0.002 (2)	0.002 (2)	−0.009 (3)
C4	0.017 (3)	0.014 (3)	0.027 (3)	0.005 (2)	−0.002 (2)	−0.003 (2)
C5	0.011 (2)	0.013 (2)	0.009 (2)	−0.002 (2)	−0.0038 (18)	−0.0037 (19)
C6	0.017 (3)	0.012 (2)	0.005 (2)	0.001 (2)	0.002 (2)	−0.0028 (19)
C7	0.009 (2)	0.008 (2)	0.011 (3)	0.0018 (18)	0.000 (2)	−0.0007 (19)
N3	0.011 (2)	0.017 (2)	0.013 (2)	−0.0023 (17)	0.0040 (17)	0.0027 (18)
C8	0.014 (3)	0.029 (3)	0.017 (3)	0.001 (2)	0.008 (2)	−0.004 (2)
C9	0.026 (3)	0.017 (3)	0.019 (3)	−0.001 (2)	0.005 (2)	0.005 (2)
C10	0.011 (2)	0.004 (2)	0.011 (3)	−0.0030 (18)	−0.002 (2)	0.000 (2)
C11	0.018 (3)	0.013 (3)	0.013 (3)	−0.001 (2)	−0.001 (2)	−0.004 (2)
C12	0.009 (2)	0.013 (3)	0.012 (3)	−0.0002 (19)	0.000 (2)	0.001 (2)
O1	0.0090 (16)	0.0135 (18)	0.0064 (17)	−0.0018 (13)	0.0008 (14)	−0.0002 (14)
Si1	0.0086 (6)	0.0130 (7)	0.0091 (7)	−0.0004 (5)	−0.0014 (5)	0.0002 (6)
C13	0.016 (3)	0.018 (3)	0.016 (3)	−0.001 (2)	−0.002 (2)	0.005 (2)
C14	0.020 (3)	0.022 (3)	0.010 (3)	−0.001 (2)	0.001 (2)	0.000 (2)
C15	0.015 (2)	0.028 (3)	0.016 (3)	−0.004 (3)	0.002 (2)	0.003 (2)

Br2—C6	1.926 (5)	C8—H8C	0.9800
N1—C5	1.319 (6)	C9—H9A	0.9800
N1—C1	1.475 (6)	C9—H9B	0.9800
N1—C2	1.476 (6)	C9—H9C	0.9800
C1—H1A	0.9800	C10—O1	1.445 (6)
C1—H1B	0.9800	C10—C12	1.515 (7)
C1—H1C	0.9800	C10—C11	1.530 (6)
C2—H2A	0.9800	C11—H11A	0.9800
C2—H2B	0.9800	C11—H11B	0.9800
C2—H2C	0.9800	C11—H11C	0.9800
N2—C5	1.333 (6)	C12—H12A	0.9800
N2—C4	1.470 (6)	C12—H12B	0.9800
N2—C3	1.475 (6)	C12—H12C	0.9800
C3—H3A	0.9800	O1—Si1	1.669 (3)
C3—H3B	0.9800	Si1—C15	1.854 (5)
C3—H3C	0.9800	Si1—C13	1.860 (5)
C4—H4A	0.9800	Si1—C14	1.862 (5)
C4—H4B	0.9800	C13—H13A	0.9800
C4—H4C	0.9800	C13—H13B	0.9800
C5—C6	1.491 (7)	C13—H13C	0.9800
C6—C7	1.327 (7)	C14—H14A	0.9800
C7—N3	1.433 (6)	C14—H14B	0.9800
C7—C10	1.542 (7)	C14—H14C	0.9800
N3—C8	1.458 (6)	C15—H15A	0.9800
N3—C9	1.464 (6)	C15—H15B	0.9800
C8—H8A	0.9800	C15—H15C	0.9800
C8—H8B	0.9800
C5—N1—C1	120.3 (4)	N3—C9—H9B	109.5
C5—N1—C2	124.4 (4)	H9A—C9—H9B	109.5
C1—N1—C2	114.6 (4)	N3—C9—H9C	109.5
N1—C1—H1A	109.5	H9A—C9—H9C	109.5
N1—C1—H1B	109.5	H9B—C9—H9C	109.5
H1A—C1—H1B	109.5	O1—C10—C12	110.4 (4)
N1—C1—H1C	109.5	O1—C10—C11	109.1 (4)
H1A—C1—H1C	109.5	C12—C10—C11	110.9 (4)
H1B—C1—H1C	109.5	O1—C10—C7	108.6 (4)
N1—C2—H2A	109.5	C12—C10—C7	109.5 (4)
N1—C2—H2B	109.5	C11—C10—C7	108.2 (4)
H2A—C2—H2B	109.5	C10—C11—H11A	109.5
N1—C2—H2C	109.5	C10—C11—H11B	109.5
H2A—C2—H2C	109.5	H11A—C11—H11B	109.5
H2B—C2—H2C	109.5	C10—C11—H11C	109.5
C5—N2—C4	122.8 (4)	H11A—C11—H11C	109.5
C5—N2—C3	124.1 (4)	H11B—C11—H11C	109.5
C4—N2—C3	112.7 (4)	C10—C12—H12A	109.5
N2—C3—H3A	109.5	C10—C12—H12B	109.5
N2—C3—H3B	109.5	H12A—C12—H12B	109.5
H3A—C3—H3B	109.5	C10—C12—H12C	109.5
N2—C3—H3C	109.5	H12A—C12—H12C	109.5
H3A—C3—H3C	109.5	H12B—C12—H12C	109.5
H3B—C3—H3C	109.5	C10—O1—Si1	128.7 (3)
N2—C4—H4A	109.5	O1—Si1—C15	106.0 (2)
N2—C4—H4B	109.5	O1—Si1—C13	112.4 (2)
H4A—C4—H4B	109.5	C15—Si1—C13	106.3 (2)
N2—C4—H4C	109.5	O1—Si1—C14	113.5 (2)
H4A—C4—H4C	109.5	C15—Si1—C14	109.4 (2)
H4B—C4—H4C	109.5	C13—Si1—C14	109.0 (2)
N1—C5—N2	123.6 (4)	Si1—C13—H13A	109.5
N1—C5—C6	119.4 (4)	Si1—C13—H13B	109.5
N2—C5—C6	116.6 (4)	H13A—C13—H13B	109.5
C7—C6—C5	129.3 (4)	Si1—C13—H13C	109.5
C7—C6—Br2	121.8 (4)	H13A—C13—H13C	109.5
C5—C6—Br2	108.8 (3)	H13B—C13—H13C	109.5
C6—C7—N3	124.5 (5)	Si1—C14—H14A	109.5
C6—C7—C10	123.9 (4)	Si1—C14—H14B	109.5
N3—C7—C10	111.6 (4)	H14A—C14—H14B	109.5
C7—N3—C8	117.4 (4)	Si1—C14—H14C	109.5
C7—N3—C9	115.8 (4)	H14A—C14—H14C	109.5
C8—N3—C9	113.7 (4)	H14B—C14—H14C	109.5
N3—C8—H8A	109.5	Si1—C15—H15A	109.5
N3—C8—H8B	109.5	Si1—C15—H15B	109.5
H8A—C8—H8B	109.5	H15A—C15—H15B	109.5
N3—C8—H8C	109.5	Si1—C15—H15C	109.5
H8A—C8—H8C	109.5	H15A—C15—H15C	109.5
H8B—C8—H8C	109.5	H15B—C15—H15C	109.5
N3—C9—H9A	109.5
C1—N1—C5—N2	167.2 (5)	C6—C7—N3—C8	77.4 (6)
C2—N1—C5—N2	−23.8 (8)	C10—C7—N3—C8	−105.1 (5)
C1—N1—C5—C6	−20.1 (7)	C6—C7—N3—C9	−61.4 (6)
C2—N1—C5—C6	148.9 (5)	C10—C7—N3—C9	116.1 (5)
C4—N2—C5—N1	161.7 (5)	C6—C7—C10—O1	−7.7 (6)
C3—N2—C5—N1	−25.9 (7)	N3—C7—C10—O1	174.8 (4)
C4—N2—C5—C6	−11.3 (7)	C6—C7—C10—C12	−128.4 (5)
C3—N2—C5—C6	161.1 (4)	N3—C7—C10—C12	54.1 (5)
N1—C5—C6—C7	104.0 (6)	C6—C7—C10—C11	110.6 (5)
N2—C5—C6—C7	−82.7 (6)	N3—C7—C10—C11	−66.9 (5)
N1—C5—C6—Br2	−78.9 (5)	C12—C10—O1—Si1	−40.7 (5)
N2—C5—C6—Br2	94.4 (4)	C11—C10—O1—Si1	81.4 (5)
C5—C6—C7—N3	169.1 (5)	C7—C10—O1—Si1	−160.9 (3)
Br2—C6—C7—N3	−7.7 (7)	C10—O1—Si1—C15	−163.6 (4)
C5—C6—C7—C10	−8.1 (8)	C10—O1—Si1—C13	80.7 (4)
Br2—C6—C7—C10	175.1 (3)	C10—O1—Si1—C14	−43.5 (4)

D—H···A	D—H	H···A	D···A	D—H···A
C3—H3C···Br1i	0.98	2.81	3.742 (3)	159
C14—H14B···Br1ii	0.98	2.87	3.790 (3)	156

Table 1

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C3—H3C⋯Br1i	0.98	2.81	3.742 (3)	159
C14—H14B⋯Br1ii	0.98	2.87	3.790 (3)	156

Symmetry codes: (i) ; (ii) .