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organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 6| June 2012| Page o1812
doi:10.1107/S1600536812021873

3-Phenyl-N,N,N′,N′-tetra­methyl-1-ethyne-1-carboximidamidium bromide

Ioannis Tiritirisa and Willi Kantlehnerb*

aInstitut für Organische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany, and bFakultät Chemie/Organische Chemie, Hochschule Aalen, Beethovenstrasse 1, D-73430 Aalen, Germany
*Correspondence e-mail: willi.kantlehner@htw-aalen.de

(Received 10 May 2012; accepted 14 May 2012; online 19 May 2012)

The reaction of 3,3,3-tris­(dimethyl­amino)-1-phenyl­prop-1-yne with bromine in pentane yields the title compound, C13H17N2+·Br−. The acetyl­enic bond distance [1.197 (2) Å] is consistent with a C≡C triple bond. The amidinium C=N bonds [1.325 (2) and 1.330 (2) Å] have double-bond character and the positive charge is delocalized between the two dimethyl­amino groups.

Related literature

For the synthesis of alkynyl orthoamides and acetyl­enic amidinium salts, see: Weingärtner et al. (2011[Weingärtner, W., Kantlehner, W. & Maas, G. (2011). Synthesis, 2, 265-272.]). For the synthesis of vinyl­ogous guanidinium iodides and bromides, see: Kantlehner et al. (2012[Kantlehner, W., Stieglitz, R., Kress, R., Frey, W. & Tiritiris, I. (2012). Synthesis. In the press. ]). For the crystal structure of N,N,N′,N′,N′′,N′′,N′′′,N′′′-octa­methyl-(but-2-yne)-bis­(amidinium)-bis­(tetra­fluoridoborate), see: Drandarov et al. (2012[Drandarov, K., Tiritiris, I., Wassiljew, O., Siehl, H.-U. & Kantlehner, W. (2012). Chem. Eur. J. doi: 10.1002/chem.201103695. ]).

[Scheme 1]

Experimental

Crystal data

  • C13H17N2+·Br−

  • Mr = 281.19

  • Monoclinic, P 21 /c

  • a = 13.1009 (8) Å

  • b = 10.6538 (6) Å

  • c = 9.6611 (6) Å

  • β = 100.276 (3)°

  • V = 1326.81 (14) Å3

  • Z = 4

  • Mo Kα radiation

  • μ = 3.08 mm−1

  • T = 100 K

  • 0.28 × 0.20 × 0.15 mm
Data collection

  • Bruker Kappa APEXII DUO diffractometer

  • Absorption correction: multi-scan (Blessing, 1995)[Blessing, R. H. (1995). Acta Cryst. A51, 33-38.] Tmin = 0.483, Tmax = 0.630

  • 27687 measured reflections

  • 4075 independent reflections

  • 3466 reflections with I > 2σ(I)

  • Rint = 0.032
Refinement

  • R[F2 > 2σ(F2)] = 0.021

  • wR(F2) = 0.052

  • S = 1.07

  • 4075 reflections

  • 149 parameters

  • H-atom parameters constrained

  • Δρmax = 0.38 e Å−3

  • Δρmin = −0.43 e Å−3

Data collection: APEX2 (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); cell refinement: SAINT (Bruker, 2008[Bruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.]); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: DIAMOND (Brandenburg & Putz, 2005[Brandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.]); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536812021873/kp2415sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536812021873/kp2415Isup2.hkl

checkCIF report


Comment top

Acetylenic amidinium salts are characterised by a carbon-carbon triple bond, which is in conjugation with an amidinium function. They can be prepared by cleavage of alkyne orthoamides with triethylsilyltriflate or benzoyl chloride (Weingärtner et al., 2011). Various alkyne orthoamides are transformed by elemental iodine or bromine to vinylogous guanidinium iodides or bromides (Kantlehner et al., 2012). Phenyl substituted alkyne orthoamides like 3,3,3-tris(dimethylamino)-1-phenyl-prop-1-yne (Weingärtner et al., 2011) behave differently, it reacts with bromine to give the title compound. According to the structure analysis, the C–N bond lengths in the amidinium unit are 1.325 (2) and 1.330 (2) Å, indicating double bond character. The positive charge in the cation is distributed between both dimethylamino groups. The bonds between the N atoms and the terminal C-methyl groups, all have values close to a typical single bond (1.462 (2)–1.465 (2) Å). The triple bond between C6 and C7 measures 1.197 (2) Å, with nearly linear C7–C6–C1 and C6–C7–C8 angles (176.3 (1) and 178.4 (1)°). The bond lengths between C7 and C8 as well as C1 and C6 are 1.427 (2) and 1.430 (2) Å, respectively. Similar geometric parameters have been observed in the crystal structure analysis of N,N,N',N',N'',N'',N''',N'''-octamethyl(but-2-yne)bis(amidinium)bis(tetrafluoroborate) (Drandarov et al., 2012). The planes built up from the amidinium unit (N1, C1, N2) and the phenyl ring (C9, C8, C13) are twisted to each other by up to 10.3 (1)° (Fig. 1). Finally, no interactions between the cations and the bromide ions have been observed.

Related literature top

For the synthesis of alkynyl orthoamides and acetylenic amidinium salts, see: Weingärtner et al. (2011). For the synthesis of vinylogous guanidinium iodides and bromides, see: Kantlehner et al. (2012). For the crystal structure of N,N,N',N',N'',N'',N''',N'''-octamethyl-(but-2-yne)-bis(amidinium)-bis(tetrafluoridoborate), see: Drandarov et al. (2012).

Experimental top

To a solution of 3,3,3-tris(dimethylamino)-1-phenyl-prop-1-yne (7.0 g, 28.5 mmol) in pentane (50 mL) was added dropwise a solution of bromine (4.56 g, 28.5 mmol) in pentane (50 mL) at 273 K with stirring. After 2 h stirring at ambient temperature the pale-yellow precipitate was filtered off in vacuo and recrystallised from acetonitrile; yield: 6.4 g (56%), pale-yellow single crystals. 1H NMR (60 MHz, CDCl3/TMS): d = 3.42 (s, 12 H, NMe2), 7.20–7.80 (m, 5 H, Ph–H).

Refinement top

Hydrogen atoms bound to aromatic carbon atoms were placed in calculated positions with d(C—H) = 0.95 Å and were included in the refinement in the riding model approximation, with U(H) set to 1.2 Ueq(C). The hydrogen atoms of the methyl group were allowed to rotate with a fixed angle around the C–N bond to best fit the experimental electron density, with U(H) set to 1.5 Ueq(C) and d(C—H) = 0.98 Å.

Structure description top

Acetylenic amidinium salts are characterised by a carbon-carbon triple bond, which is in conjugation with an amidinium function. They can be prepared by cleavage of alkyne orthoamides with triethylsilyltriflate or benzoyl chloride (Weingärtner et al., 2011). Various alkyne orthoamides are transformed by elemental iodine or bromine to vinylogous guanidinium iodides or bromides (Kantlehner et al., 2012). Phenyl substituted alkyne orthoamides like 3,3,3-tris(dimethylamino)-1-phenyl-prop-1-yne (Weingärtner et al., 2011) behave differently, it reacts with bromine to give the title compound. According to the structure analysis, the C–N bond lengths in the amidinium unit are 1.325 (2) and 1.330 (2) Å, indicating double bond character. The positive charge in the cation is distributed between both dimethylamino groups. The bonds between the N atoms and the terminal C-methyl groups, all have values close to a typical single bond (1.462 (2)–1.465 (2) Å). The triple bond between C6 and C7 measures 1.197 (2) Å, with nearly linear C7–C6–C1 and C6–C7–C8 angles (176.3 (1) and 178.4 (1)°). The bond lengths between C7 and C8 as well as C1 and C6 are 1.427 (2) and 1.430 (2) Å, respectively. Similar geometric parameters have been observed in the crystal structure analysis of N,N,N',N',N'',N'',N''',N'''-octamethyl(but-2-yne)bis(amidinium)bis(tetrafluoroborate) (Drandarov et al., 2012). The planes built up from the amidinium unit (N1, C1, N2) and the phenyl ring (C9, C8, C13) are twisted to each other by up to 10.3 (1)° (Fig. 1). Finally, no interactions between the cations and the bromide ions have been observed.

For the synthesis of alkynyl orthoamides and acetylenic amidinium salts, see: Weingärtner et al. (2011). For the synthesis of vinylogous guanidinium iodides and bromides, see: Kantlehner et al. (2012). For the crystal structure of N,N,N',N',N'',N'',N''',N'''-octamethyl-(but-2-yne)-bis(amidinium)-bis(tetrafluoridoborate), see: Drandarov et al. (2012).

Computing details top

Data collection: APEX2 (Bruker, 2008); cell refinement: SAINT (Bruker, 2008); data reduction: SAINT (Bruker, 2008); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The crystal structure of N,N,N',N'- tetramethyl-3-phenyl-prop-2-yne-amidinium bromide with atom labels and 50% probability displacement ellipsoids.
3-Phenyl-N,N,N',N'-tetramethyl-1-ethyne- 1-carboximidamidium bromide top
Crystal data top
C13H17N2+·Br−F(000) = 576
Mr = 281.19Dx = 1.408 Mg m−3
Monoclinic, P21/cMelting point: 441 K
Hall symbol: -P 2ybcMo Kα radiation, λ = 0.71073 Å
a = 13.1009 (8) ÅCell parameters from 4075 reflections
b = 10.6538 (6) Åθ = 2.5–30.6°
c = 9.6611 (6) ŵ = 3.08 mm−1
β = 100.276 (3)°T = 100 K
V = 1326.81 (14) Å3Block, yellow
Z = 40.28 × 0.20 × 0.15 mm
Data collection top
Bruker Kappa APEXII DUO
diffractometer		4075 independent reflections
Radiation source: sealed tube3466 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
φ scans, and ω scansθmax = 30.6°, θmin = 2.5°
Absorption correction: multi-scan
(Blessing, 1995)		h = −18→18
Tmin = 0.483, Tmax = 0.630k = −15→15
27687 measured reflectionsl = −13→13
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)] = 0.021Hydrogen site location: difference Fourier map
wR(F2) = 0.052H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.024P)2 + 0.4023P]
where P = (Fo2 + 2Fc2)/3
4075 reflections(Δ/σ)max < 0.001
149 parametersΔρmax = 0.38 e Å−3
0 restraintsΔρmin = −0.43 e Å−3
Crystal data top
C13H17N2+·Br−V = 1326.81 (14) Å3
Mr = 281.19Z = 4
Monoclinic, P21/cMo Kα radiation
a = 13.1009 (8) ŵ = 3.08 mm−1
b = 10.6538 (6) ÅT = 100 K
c = 9.6611 (6) Å0.28 × 0.20 × 0.15 mm
β = 100.276 (3)°
Data collection top
Bruker Kappa APEXII DUO
diffractometer		4075 independent reflections
Absorption correction: multi-scan
(Blessing, 1995)		3466 reflections with I > 2σ(I)
Tmin = 0.483, Tmax = 0.630Rint = 0.032
27687 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0210 restraints
wR(F2) = 0.052H-atom parameters constrained
S = 1.07Δρmax = 0.38 e Å−3
4075 reflectionsΔρmin = −0.43 e Å−3
149 parameters
Special details top

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Br10.313905 (9)0.523031 (12)0.155779 (13)0.01703 (4)
C10.29358 (9)0.46256 (11)0.66879 (12)0.0128 (2)
N10.35589 (8)0.56042 (10)0.66379 (10)0.01344 (19)
N20.30756 (8)0.37987 (10)0.77285 (11)0.0147 (2)
C20.41450 (10)0.62002 (12)0.79005 (13)0.0164 (2)
H2A0.38820.59040.87310.025*
H2B0.40650.71130.78230.025*
H2C0.48810.59820.79920.025*
C30.35920 (11)0.62655 (13)0.53213 (13)0.0205 (3)
H3A0.31400.58380.45460.031*
H3B0.43050.62710.51430.031*
H3C0.33530.71310.53920.031*
C40.22431 (11)0.29642 (12)0.79900 (15)0.0207 (3)
H4A0.15800.32550.74510.031*
H4B0.22100.29700.89950.031*
H4C0.23820.21090.76990.031*
C50.40815 (10)0.35338 (13)0.86079 (14)0.0203 (3)
H5A0.46350.39000.81750.031*
H5B0.41810.26240.86950.031*
H5C0.41030.39000.95430.031*
C60.20698 (10)0.44506 (11)0.55744 (13)0.0153 (2)
C70.13169 (9)0.42701 (11)0.46956 (13)0.0148 (2)
C80.04099 (9)0.40275 (11)0.36723 (12)0.0133 (2)
C9−0.02930 (10)0.31159 (11)0.39520 (14)0.0170 (2)
H9A−0.01560.26510.48040.020*
C10−0.11893 (10)0.28928 (12)0.29838 (15)0.0204 (3)
H10A−0.16690.22740.31710.024*
C11−0.13845 (10)0.35719 (13)0.17439 (14)0.0203 (3)
H11A−0.20020.34200.10840.024*
C12−0.06867 (10)0.44725 (13)0.14572 (14)0.0195 (3)
H12A−0.08280.49350.06030.023*
C130.02160 (10)0.46995 (12)0.24136 (13)0.0167 (2)
H13A0.06990.53080.22130.020*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Br10.01516 (6)0.01901 (6)0.01757 (7)0.00196 (5)0.00471 (4)−0.00012 (5)
C10.0109 (5)0.0140 (5)0.0139 (5)0.0021 (4)0.0035 (4)−0.0027 (4)
N10.0132 (5)0.0152 (4)0.0115 (4)−0.0012 (4)0.0012 (4)−0.0005 (4)
N20.0138 (5)0.0147 (5)0.0158 (5)0.0012 (4)0.0034 (4)0.0016 (4)
C20.0149 (6)0.0184 (6)0.0150 (6)−0.0022 (4)0.0001 (4)−0.0030 (4)
C30.0242 (7)0.0219 (6)0.0151 (6)−0.0052 (5)0.0028 (5)0.0034 (5)
C40.0224 (7)0.0158 (6)0.0258 (7)−0.0025 (5)0.0091 (5)0.0024 (5)
C50.0184 (6)0.0224 (6)0.0194 (6)0.0077 (5)0.0010 (5)0.0047 (5)
C60.0148 (6)0.0131 (5)0.0182 (6)0.0011 (4)0.0034 (4)−0.0018 (4)
C70.0140 (5)0.0130 (5)0.0179 (6)0.0008 (4)0.0045 (4)−0.0020 (4)
C80.0105 (5)0.0125 (5)0.0167 (6)0.0008 (4)0.0023 (4)−0.0039 (4)
C90.0162 (6)0.0141 (5)0.0216 (6)−0.0001 (4)0.0056 (5)−0.0007 (4)
C100.0131 (6)0.0171 (6)0.0323 (7)−0.0037 (5)0.0076 (5)−0.0081 (5)
C110.0105 (6)0.0252 (6)0.0246 (6)0.0019 (5)0.0010 (5)−0.0124 (5)
C120.0171 (6)0.0254 (6)0.0153 (6)0.0034 (5)0.0009 (5)−0.0022 (5)
C130.0140 (6)0.0169 (6)0.0191 (6)−0.0015 (4)0.0032 (5)−0.0005 (5)
Geometric parameters (Å, º) top
C1—N21.3246 (15)C5—H5A0.9800
C1—N11.3304 (16)C5—H5B0.9800
C1—C61.4296 (17)C5—H5C0.9800
N1—C31.4615 (15)C6—C71.1966 (17)
N1—C21.4651 (15)C7—C81.4273 (17)
N2—C51.4625 (16)C8—C131.3949 (17)
N2—C41.4636 (16)C8—C91.3974 (17)
C2—H2A0.9800C9—C101.3851 (18)
C2—H2B0.9800C9—H9A0.9500
C2—H2C0.9800C10—C111.384 (2)
C3—H3A0.9800C10—H10A0.9500
C3—H3B0.9800C11—C121.3870 (19)
C3—H3C0.9800C11—H11A0.9500
C4—H4A0.9800C12—C131.3860 (18)
C4—H4B0.9800C12—H12A0.9500
C4—H4C0.9800C13—H13A0.9500
N2—C1—N1123.10 (11)N2—C5—H5A109.5
N2—C1—C6117.91 (11)N2—C5—H5B109.5
N1—C1—C6118.99 (11)H5A—C5—H5B109.5
C1—N1—C3121.53 (10)N2—C5—H5C109.5
C1—N1—C2122.91 (10)H5A—C5—H5C109.5
C3—N1—C2115.04 (10)H5B—C5—H5C109.5
C1—N2—C5123.89 (11)C7—C6—C1176.30 (13)
C1—N2—C4121.91 (11)C6—C7—C8178.36 (13)
C5—N2—C4113.86 (10)C13—C8—C9120.10 (11)
N1—C2—H2A109.5C13—C8—C7120.69 (11)
N1—C2—H2B109.5C9—C8—C7119.20 (11)
H2A—C2—H2B109.5C10—C9—C8119.81 (12)
N1—C2—H2C109.5C10—C9—H9A120.1
H2A—C2—H2C109.5C8—C9—H9A120.1
H2B—C2—H2C109.5C11—C10—C9119.90 (12)
N1—C3—H3A109.5C11—C10—H10A120.0
N1—C3—H3B109.5C9—C10—H10A120.0
H3A—C3—H3B109.5C10—C11—C12120.53 (12)
N1—C3—H3C109.5C10—C11—H11A119.7
H3A—C3—H3C109.5C12—C11—H11A119.7
H3B—C3—H3C109.5C13—C12—C11120.13 (12)
N2—C4—H4A109.5C13—C12—H12A119.9
N2—C4—H4B109.5C11—C12—H12A119.9
H4A—C4—H4B109.5C12—C13—C8119.51 (11)
N2—C4—H4C109.5C12—C13—H13A120.2
H4A—C4—H4C109.5C8—C13—H13A120.2
H4B—C4—H4C109.5
N2—C1—N1—C3160.73 (11)C13—C8—C9—C10−0.83 (18)
C6—C1—N1—C3−19.49 (17)C7—C8—C9—C10178.38 (11)
N2—C1—N1—C2−27.94 (18)C8—C9—C10—C110.07 (18)
C6—C1—N1—C2151.84 (11)C9—C10—C11—C120.32 (19)
N1—C1—N2—C5−25.57 (18)C10—C11—C12—C130.06 (19)
C6—C1—N2—C5154.65 (11)C11—C12—C13—C8−0.82 (19)
N1—C1—N2—C4161.57 (12)C9—C8—C13—C121.20 (18)
C6—C1—N2—C4−18.20 (17)C7—C8—C13—C12−178.00 (11)

Experimental details

Crystal data
Chemical formulaC13H17N2+·Br−
Mr281.19
Crystal system, space groupMonoclinic, P21/c
Temperature (K)100
a, b, c (Å)13.1009 (8), 10.6538 (6), 9.6611 (6)
β (°) 100.276 (3)
V (Å3)1326.81 (14)
Z4
Radiation typeMo Kα
µ (mm−1)3.08
Crystal size (mm)0.28 × 0.20 × 0.15
Data collection
DiffractometerBruker Kappa APEXII DUO
Absorption correctionMulti-scan
(Blessing, 1995)
Tmin, Tmax0.483, 0.630
No. of measured, independent and
observed [I > 2σ(I)] reflections		27687, 4075, 3466
Rint0.032
(sin θ/λ)max (Å−1)0.717
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.021, 0.052, 1.07
No. of reflections4075
No. of parameters149
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å−3)0.38, −0.43

Computer programs: APEX2 (Bruker, 2008), SAINT (Bruker, 2008), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg & Putz, 2005).

 

Acknowledgements

The authors thank Dr Wolfgang Frey (Institut für Organ­ische Chemie, Universität Stuttgart) for measuring the crystal data.

References

First citationBlessing, R. H. (1995). Acta Cryst. A51, 33–38.  CrossRef CAS Web of Science IUCr Journals Google Scholar
 First citationBrandenburg, K. & Putz, H. (2005). DIAMOND. Crystal Impact GbR, Bonn, Germany.  Google Scholar
 First citationBruker (2008). APEX2 and SAINT. Bruker AXS Inc., Madison, Wisconsin, USA.  Google Scholar
 First citationDrandarov, K., Tiritiris, I., Wassiljew, O., Siehl, H.-U. & Kantlehner, W. (2012). Chem. Eur. J. doi: 10.1002/chem.201103695.  Google Scholar
 First citationKantlehner, W., Stieglitz, R., Kress, R., Frey, W. & Tiritiris, I. (2012). Synthesis. In the press.  Google Scholar
 First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
 First citationWeingärtner, W., Kantlehner, W. & Maas, G. (2011). Synthesis, 2, 265–272.  Google Scholar

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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 68| Part 6| June 2012| Page o1812
doi:10.1107/S1600536812021873
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