1-Nitro-4-(1-propyn-1-yl)benzene

The title compound, C₉H₇NO₂, was prepared by alkynylation of 4-iodo­nitro­benzene with 1,3-dili­thio­propyne in the presence of 1 equivalent of CuI and catalytic amounts of Pd(PPh₃)₂Cl₂. The complete mol­ecule is generated by crystallographic twofold symmetry with the C—N and C—C≡C—C units lying on the rotation axis. No directional inter­actions beyond normal van der Waals contacts could be identified in the packing.

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Chemical scheme

Structure description

One of the most general methods for the synthesis of aromatic alkynes is the alkynylation of halogenated aromatic rings (Negishi & Anastasia, 2003). Today, the Sonogashira reaction is probably the most extensively used protocol for the synthesis of mono and di-substituted acetyl­enes (Sonogashira et al., 1975). In this reaction an aromatic (or vin­yl) halide is treated with the corresponding acetyl­ene, in the presence of catalytic amounts of Pd⁰ or Pd^II tri­phenyl­phosphine complexes, an amine (i.e., Et₂NH) and catalytic amounts of CuI at room temperature.

Specifically 1-propynylarenes, which can be obtained by the above-mentioned alkynylation protocols, using prop-1-yne, are not only very valuable synthetic inter­mediates, but also these structures are present in a wide number of natural products (Carpita et al., 1985; Christensen & Lam, 1991), many of which have important biological activity (Zhang et al., 2014).

As part of our work in this area, we now report the synthesis and crystal structure of the title compound, 1. The C7≡C8 distance of 1.195 (4) Å is consistent with previous reported values (Umaña et al., 2018). The complete mol­ecule is generated by a crystallographic twofold axis with atoms C1, C4, C7, C8, C9 and N1 lying on the rotation axis. The nitro group is close to being coplanar with its attached ring as indicated by the O1—N1—C1—C2ⁱ torsion angle of 171.25 (14)° (Fig. 1). The extended structure (Fig. 2) shows neither hydrogen bonding nor aromatic π–π stacking.

Figure 1 The title mol­ecule, 1, with 50% probability ellipsoids. Unlabelled atoms are generated by the symmetry operation  − x, y, −z.

Figure 2 The crystal packing of the title compound.

Synthesis and crystallization

The title compound, 1, was synthesized by a variation of the Sonogashira reaction. Thus, 4-iodo­nitro­benzene, 2, was treated with the dianion 1,3-dili­thio­propyne, 3, in the presence of one equivalent of CuI (instead of catalytic amounts) and catalytic amounts of Pd(PPh₃)₂Cl₂ (Fig. 3). The 1,3-dilithipropyne, 3, was prepared from 2,3-di­chloro­propene by sequential treatment with magnesium and n-BuLi as previously reported (Umaña & Cabezas, 2017; Cabezas et al., 2018). After ether–water partition, the crude reaction was purified by column chromatography (ether:hexane, 30:70), to obtain the title compound, 1, in 72% yield. The product was recrystallized from ethyl acetate solution at room temperature in the form of pale-yellow blocks.

Figure 3 A synthetic scheme for the preparation of title compound 1.

Refinement

Crystal data, data collection and structure refinement are summarized in Table 1.

Table 1
Experimental details

Crystal data
Chemical formula	C9H7NO2
Mr	161.16
Crystal system, space group	Monoclinic, I2/a
Temperature (K)	100
a, b, c (Å)	7.3633 (13), 12.0641 (16), 8.9185 (19)
β (°)	103.738 (13)
V (Å^3)	769.6 (2)
Z	4
Radiation type	Cu Kα
μ (mm^−1)	0.83
Crystal size (mm)	0.15 × 0.13 × 0.10
Data collection
Diffractometer	Bruker D8 Venture
Absorption correction	Multi-scan (SADABS; Bruker, 2015)
Tmin, Tmax	0.509, 0.753
No. of measured, independent and observed [I > 2σ(I)] reflections	7605, 717, 571
Rint	0.109
(sin θ/λ)max (Å^−1)	0.606
Refinement
R[F^2 > 2σ(F^2)], wR(F^2), S	0.057, 0.179, 1.13
No. of reflections	717
No. of parameters	60
H-atom treatment	H-atom parameters constrained
Δρmax, Δρmin (e Å^−3)	0.26, −0.37
Computer programs: APEX3 and SAINT (Bruker, 2015), SHELXT (Sheldrick, 2015a), SHELXL2018 (Sheldrick, 2015b), shelXle (Hübschle, 2011) and publCIF (Westrip, 2010).

Structural data

Computing details

Data collection: APEX3 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: shelXle (Hübschle, 2011); software used to prepare material for publication: publCIF (Westrip, 2010).

1-Nitro-4-(1-propyn-1-yl)benzene

Crystal data

C9H7NO2	F(000) = 336
Mr = 161.16	Dx = 1.391 Mg m^−3
Monoclinic, I2/a	Cu Kα radiation, λ = 1.54178 Å
a = 7.3633 (13) Å	Cell parameters from 4037 reflections
b = 12.0641 (16) Å	θ = 6.3–68.4°
c = 8.9185 (19) Å	µ = 0.83 mm^−1
β = 103.738 (13)°	T = 100 K
V = 769.6 (2) Å^3	Block, pale yellow
Z = 4	0.15 × 0.13 × 0.10 mm

Data collection

Bruker D8 Venture diffractometer	571 reflections with I > 2σ(I)
Radiation source: Incoatec Microsource	Rint = 0.109
ω scans	θmax = 69.2°, θmin = 6.3°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −8→8
Tmin = 0.509, Tmax = 0.753	k = −14→14
7605 measured reflections	l = −10→10
717 independent reflections

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.057	H-atom parameters constrained
wR(F^2) = 0.179	w = 1/[σ^2(Fo^2) + (0.1002P)^2 + 0.5352P] where P = (Fo^2 + 2Fc^2)/3
S = 1.13	(Δ/σ)max < 0.001
717 reflections	Δρmax = 0.26 e Å^−3
60 parameters	Δρmin = −0.37 e Å^−3
0 restraints	Extinction correction: SHELXL2018 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0025 (10)

Special details

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. All H atoms were located initially by difference Fourier synthesis and relocated to idealized locations (C—H = 0.95–0.98 Å) and refined as riding atoms.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.3309 (2)	0.64648 (13)	0.11827 (18)	0.0376 (6)
N1	0.250000	0.5986 (2)	0.000000	0.0286 (7)
C1	0.250000	0.4765 (2)	0.000000	0.0266 (8)
C2	0.3613 (3)	0.42172 (19)	0.1242 (2)	0.0286 (7)
H2	0.435644	0.461834	0.208422	0.034*
C3	0.3623 (3)	0.30639 (19)	0.1232 (3)	0.0299 (7)
H3	0.439548	0.266962	0.206608	0.036*
C4	0.250000	0.2484 (2)	0.000000	0.0282 (8)
C7	0.250000	0.1283 (2)	0.000000	0.0298 (8)
C8	0.250000	0.0292 (3)	0.000000	0.0317 (8)
C9	0.250000	−0.0924 (3)	0.000000	0.0337 (9)
H9A	0.132345	−0.119488	−0.065837	0.040*	0.5
H9B	0.262645	−0.119487	0.105581	0.040*	0.5
H9C	0.355010	−0.119487	−0.039745	0.040*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0414 (10)	0.0234 (10)	0.0409 (11)	−0.0031 (7)	−0.0042 (7)	−0.0041 (7)
N1	0.0262 (13)	0.0213 (14)	0.0351 (15)	0.000	0.0008 (10)	0.000
C1	0.0249 (15)	0.0172 (16)	0.0371 (18)	0.000	0.0058 (13)	0.000
C2	0.0262 (12)	0.0232 (13)	0.0333 (13)	−0.0029 (8)	0.0011 (9)	−0.0031 (9)
C3	0.0280 (12)	0.0238 (14)	0.0350 (14)	0.0020 (8)	0.0018 (9)	0.0051 (9)
C4	0.0273 (16)	0.0203 (17)	0.0373 (18)	0.000	0.0080 (12)	0.000
C7	0.0297 (17)	0.0205 (18)	0.0375 (19)	0.000	0.0048 (13)	0.000
C8	0.0285 (16)	0.026 (2)	0.0387 (19)	0.000	0.0041 (13)	0.000
C9	0.0313 (17)	0.0174 (17)	0.049 (2)	0.000	0.0021 (14)	0.000

Geometric parameters (Å, º)

N1—O1	1.226 (2)	C7—C8	1.195 (4)
N1—C1	1.473 (4)	C8—C9	1.468 (4)
C1—C2^i	1.380 (3)	C9—H9A	0.9800
C1—C2	1.380 (3)	C9—H9B	0.9800
C2—C3	1.391 (3)	C9—H9C	0.9800
C2—H2	0.9500	C9—H9A^i	0.9800
C3—C4	1.396 (3)	C9—H9B^i	0.9800
C3—H3	0.9500	C9—H9C^i	0.9800
C4—C7	1.449 (4)
O1—N1—O1^i	123.7 (3)	H9A—C9—H9B	109.5
O1—N1—C1	118.13 (13)	C8—C9—H9C	109.5
O1^i—N1—C1	118.13 (13)	H9A—C9—H9C	109.5
C2^i—C1—C2	122.8 (3)	H9B—C9—H9C	109.5
C2^i—C1—N1	118.59 (14)	C8—C9—H9A^i	109.474 (4)
C2—C1—N1	118.59 (14)	H9A—C9—H9A^i	141.1
C1—C2—C3	118.4 (2)	H9B—C9—H9A^i	56.3
C1—C2—H2	120.8	H9C—C9—H9A^i	56.2
C3—C2—H2	120.8	C8—C9—H9B^i	109.469 (5)
C2—C3—C4	120.2 (2)	H9A—C9—H9B^i	56.3
C2—C3—H3	119.9	H9B—C9—H9B^i	141.1
C4—C3—H3	119.9	H9C—C9—H9B^i	56.3
C3—C4—C3^i	119.9 (3)	H9A^i—C9—H9B^i	109.5
C3—C4—C7	120.06 (14)	C8—C9—H9C^i	109.469 (4)
C3^i—C4—C7	120.06 (14)	H9A—C9—H9C^i	56.2
C8—C7—C4	180.0	H9B—C9—H9C^i	56.3
C7—C8—C9	180.0	H9C—C9—H9C^i	141.1
C8—C9—H9A	109.5	H9A^i—C9—H9C^i	109.5
C8—C9—H9B	109.5	H9B^i—C9—H9C^i	109.5
O1—N1—C1—C2^i	171.25 (14)	N1—C1—C2—C3	−179.44 (14)
O1^i—N1—C1—C2^i	−8.75 (14)	C1—C2—C3—C4	−1.1 (3)
O1—N1—C1—C2	−8.75 (14)	C2—C3—C4—C3^i	0.57 (14)
O1^i—N1—C1—C2	171.25 (14)	C2—C3—C4—C7	−179.43 (14)
C2^i—C1—C2—C3	0.56 (14)

Symmetry code: (i) −x+1/2, y, −z.