N,N,N′,N′-Tetra­ethyl­naphthalene-1,4-dicarboxamide

In the title compound, C₂₀H₂₆N₂O₂, all bond lengths and angles are normal. The two amide groups are twisted away from the naphthalene mean plane by 86.29 (4) and 84.06 (4)°, respectively. Inter­molecular C—H...π inter­actions contribute to the crystal packing stability. One ethyl group is disordered equally over two sites.

Key indicators

• Single-crystal X-ray study
• T = 153 K
• Mean [sigma](C-C) = 0.002 Å
• Disorder in main residue
• R factor = 0.039
• wR factor = 0.117
• Data-to-parameter ratio = 17.9

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT301_ALERT_3_C Main Residue  Disorder .........................       4.00 Perc.
PLAT779_ALERT_2_C Suspect or Irrelevant (Bond) Angle in CIF ......      15.20 Deg.
              C20  -C19  -C20'    1.555   1.555   1.555

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          2

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   3 ALERT level C = Check and explain
   1 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   1 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

---

S1. Comment

1,4-Naphthalenedicarboxylic acid derivatives are a class of intermediates important for applications as monomers in the preparation of polymers (Fukuzumi et al., 1994; Tsukada et al., 1994). Previously, we have reported the crystal structures of N,N'-bis(4-nitrophenyl)naphthalene-1,4-dicarboxamide dimethylsulfoxide disolvate (Jing et al., 2006b) and N,N'-bis(2-methoxyphenyl)naphthalene-1,4-dicarboxamide (Jing et al., 2006a). Herewith we report the crystal structure of the title compound, (I).

The naphthalene ring system in (I) is essentially planar, with a maximum deviation of 0.020 (1) Å for atoms C2 and C4. As a result of steric effects, two amide groups are twisted away from the naphthalene mean plane at 86.29 (4) and 84.06 (4)°, respectively (Fig. 1). The crystal packing is stabilized by intermolecular C—H···π interactions (Table 1).

Related literature

For related crystal structures, see Jing et al. (2006a,b). For applications of 1,4-naphthalenedicarboxylic acid derivatives, see: Fukuzumi et al. (1994) and Tsukada et al. (1994).

S2. Experimental

Naphthalene-1,4-dicarboxylic acid (2 mmol) and an excess of thionyl chloride (6 mmol) in dioxane (20 ml) were boiled under reflux for 6 h. The solution was distilled under reduced pressure and a yellow solid was formed. Diethylamine (4 mmol) in tetrahydrofuran (20 ml) was added to the yellow solid and boiled under reflux for 1 d. The solution was then cooled to ambient temperature and filtered to remove the tetrahydrofuran. The precipitate was dissolved in dimethylsulfoxide and allowed to stand for one month at ambient temperature to obtain white single crystals of (I) suitable for X-ray diffraction.

S3. Refinement

The methyl group attached to atom C19 was treated as disordered between two postions with the occupancy factors fixed to 0.5. A l l H atoms were placed in calculated positions, with C—H = 0.95 and 0.98 Å, and refined using a riding model, with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: RAPID-AUTO (Rigaku, 2004); cell refinement: RAPID-AUTO (Rigaku, 2004); data reduction: RAPID-AUTO (Rigaku, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. The molecular structure of (I), showing 30% probability displacement ellipsoids and atomic numbering. H atoms have been omitted for clarity.

N,N,N',N'-Tetraethylnaphthalene-1,4-dicarboxamide

Crystal data

C20H26N2O2	F(000) = 1408
Mr = 326.43	Dx = 1.198 Mg m^−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
a = 23.1133 (14) Å	Cell parameters from 13310 reflections
b = 12.6202 (8) Å	θ = 3.2–27.5°
c = 12.9917 (9) Å	µ = 0.08 mm^−1
β = 107.293 (2)°	T = 153 K
V = 3618.3 (4) Å^3	Block, white
Z = 8	0.58 × 0.52 × 0.51 mm

Data collection

Rigaku R-AXIS RAPID diffractometer	3595 reflections with I > 2σ(I)
Radiation source: Rotating Anode	Rint = 0.020
Graphite monochromator	θmax = 27.5°, θmin = 3.2°
ω scans	h = −30→30
16253 measured reflections	k = −15→16
4142 independent reflections	l = −16→16

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)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.117	w = 1/[σ^2(Fo^2) + (0.0636P)^2 + 1.926P] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max < 0.001
4142 reflections	Δρmax = 0.27 e Å^−3
232 parameters	Δρmin = −0.19 e Å^−3
2 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0060 (5)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
O1	0.34773 (4)	0.68029 (6)	0.68184 (6)	0.0331 (2)
O2	0.35699 (4)	0.82048 (6)	0.14179 (6)	0.0341 (2)
N1	0.35264 (4)	0.52131 (7)	0.60330 (7)	0.0250 (2)
N2	0.35967 (4)	0.97548 (7)	0.23134 (7)	0.0279 (2)
C1	0.35319 (5)	0.68534 (7)	0.50255 (8)	0.0218 (2)
C2	0.30086 (5)	0.71488 (8)	0.42612 (8)	0.0248 (2)
H2	0.2629	0.6929	0.4330	0.030*
C3	0.30266 (5)	0.77771 (8)	0.33704 (8)	0.0253 (2)
H3	0.2659	0.7991	0.2857	0.030*
C4	0.35700 (5)	0.80788 (7)	0.32418 (8)	0.0224 (2)
C5	0.46980 (5)	0.80461 (8)	0.38949 (9)	0.0272 (2)
H5	0.4716	0.8444	0.3285	0.033*
C6	0.52242 (5)	0.77531 (9)	0.46494 (10)	0.0322 (3)
H6	0.5603	0.7946	0.4558	0.039*
C7	0.52062 (5)	0.71644 (9)	0.55633 (10)	0.0329 (3)
H7	0.5573	0.6971	0.6091	0.039*
C8	0.46614 (5)	0.68711 (8)	0.56913 (9)	0.0274 (2)
H8	0.4655	0.6470	0.6307	0.033*
C9	0.41065 (4)	0.71556 (7)	0.49208 (8)	0.0215 (2)
C10	0.41248 (5)	0.77666 (7)	0.40066 (8)	0.0218 (2)
C11	0.35081 (4)	0.62789 (8)	0.60333 (8)	0.0228 (2)
C12	0.36014 (5)	0.45706 (8)	0.51393 (9)	0.0297 (2)
H12A	0.3924	0.4039	0.5431	0.036*
H12B	0.3736	0.5035	0.4641	0.036*
C13	0.30299 (7)	0.40049 (12)	0.45156 (11)	0.0508 (4)
H13A	0.2885	0.3564	0.5008	0.061*
H13B	0.3115	0.3556	0.3962	0.061*
H13C	0.2719	0.4527	0.4171	0.061*
C14	0.35801 (5)	0.46542 (9)	0.70497 (9)	0.0314 (3)
H14A	0.3410	0.3931	0.6893	0.038*
H14B	0.3345	0.5035	0.7458	0.038*
C15	0.42378 (6)	0.45865 (10)	0.77230 (10)	0.0381 (3)
H15A	0.4464	0.4164	0.7340	0.046*
H15B	0.4265	0.4251	0.8416	0.046*
H15C	0.4410	0.5301	0.7849	0.046*
C16	0.35807 (5)	0.86896 (8)	0.22470 (8)	0.0241 (2)
C17	0.36309 (6)	1.03641 (9)	0.13698 (9)	0.0331 (3)
H17A	0.3455	1.1077	0.1387	0.040*
H17B	0.3389	1.0003	0.0704	0.040*
C18	0.42771 (6)	1.04733 (10)	0.13518 (11)	0.0409 (3)
H18A	0.4509	1.0877	0.1984	0.049*
H18B	0.4285	1.0846	0.0694	0.049*
H18C	0.4457	0.9768	0.1365	0.049*
C19	0.36776 (6)	1.03511 (9)	0.33181 (9)	0.0334 (3)
H19A	0.4029	1.0830	0.3422	0.040*
H19B	0.3777	0.9844	0.3927	0.040*
C20	0.3140 (3)	1.1002 (6)	0.3370 (10)	0.0529 (18)	0.50
H20A	0.3067	1.1567	0.2829	0.064*	0.50
H20B	0.3222	1.1314	0.4089	0.064*	0.50
H20C	0.2781	1.0546	0.3224	0.064*	0.50
C20'	0.3074 (3)	1.0719 (6)	0.3415 (11)	0.0505 (17)	0.50
H20D	0.2849	1.1084	0.2751	0.061*	0.50
H20E	0.3141	1.1207	0.4026	0.061*	0.50
H20F	0.2841	1.0106	0.3530	0.061*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0496 (5)	0.0274 (4)	0.0282 (4)	0.0026 (3)	0.0206 (4)	−0.0021 (3)
O2	0.0510 (5)	0.0298 (4)	0.0235 (4)	−0.0028 (3)	0.0142 (3)	−0.0036 (3)
N1	0.0318 (5)	0.0210 (4)	0.0248 (4)	−0.0019 (3)	0.0124 (4)	0.0008 (3)
N2	0.0392 (5)	0.0224 (4)	0.0211 (4)	0.0019 (3)	0.0073 (4)	0.0028 (3)
C1	0.0283 (5)	0.0171 (4)	0.0225 (5)	0.0000 (3)	0.0112 (4)	−0.0014 (3)
C2	0.0249 (5)	0.0255 (5)	0.0259 (5)	−0.0024 (4)	0.0102 (4)	−0.0020 (4)
C3	0.0265 (5)	0.0257 (5)	0.0224 (5)	0.0007 (4)	0.0051 (4)	−0.0010 (4)
C4	0.0305 (5)	0.0173 (4)	0.0199 (4)	0.0003 (4)	0.0083 (4)	−0.0018 (3)
C5	0.0311 (5)	0.0234 (5)	0.0305 (5)	−0.0003 (4)	0.0143 (4)	0.0041 (4)
C6	0.0263 (5)	0.0310 (6)	0.0427 (6)	0.0002 (4)	0.0155 (5)	0.0060 (5)
C7	0.0256 (5)	0.0325 (6)	0.0393 (6)	0.0045 (4)	0.0077 (5)	0.0088 (5)
C8	0.0290 (5)	0.0244 (5)	0.0296 (5)	0.0032 (4)	0.0097 (4)	0.0071 (4)
C9	0.0262 (5)	0.0163 (4)	0.0238 (5)	0.0012 (3)	0.0100 (4)	−0.0003 (3)
C10	0.0275 (5)	0.0166 (4)	0.0234 (5)	0.0003 (3)	0.0104 (4)	−0.0006 (3)
C11	0.0239 (5)	0.0234 (5)	0.0235 (5)	−0.0003 (4)	0.0106 (4)	0.0007 (4)
C12	0.0392 (6)	0.0219 (5)	0.0303 (5)	0.0007 (4)	0.0138 (5)	−0.0032 (4)
C13	0.0576 (9)	0.0489 (8)	0.0423 (7)	−0.0142 (7)	0.0094 (6)	−0.0142 (6)
C14	0.0420 (6)	0.0247 (5)	0.0315 (6)	−0.0042 (4)	0.0174 (5)	0.0056 (4)
C15	0.0479 (7)	0.0330 (6)	0.0321 (6)	−0.0009 (5)	0.0100 (5)	0.0081 (5)
C16	0.0273 (5)	0.0239 (5)	0.0203 (5)	0.0002 (4)	0.0061 (4)	0.0007 (4)
C17	0.0454 (7)	0.0263 (5)	0.0251 (5)	0.0028 (5)	0.0065 (5)	0.0087 (4)
C18	0.0497 (8)	0.0346 (6)	0.0393 (6)	−0.0011 (5)	0.0146 (6)	0.0114 (5)
C19	0.0489 (7)	0.0226 (5)	0.0268 (5)	0.0010 (5)	0.0083 (5)	−0.0019 (4)
C20	0.076 (3)	0.045 (4)	0.039 (2)	0.030 (3)	0.018 (2)	−0.001 (3)
C20'	0.075 (3)	0.036 (3)	0.038 (2)	0.026 (2)	0.014 (2)	0.004 (3)

Geometric parameters (Å, º)

O1—C11	1.2352 (12)	C12—H12A	0.9900
O2—C16	1.2326 (12)	C12—H12B	0.9900
N1—C11	1.3458 (13)	C13—H13A	0.9800
N1—C12	1.4681 (13)	C13—H13B	0.9800
N1—C14	1.4697 (13)	C13—H13C	0.9800
N2—C16	1.3469 (14)	C14—C15	1.5142 (17)
N2—C17	1.4691 (13)	C14—H14A	0.9900
N2—C19	1.4697 (13)	C14—H14B	0.9900
C1—C2	1.3689 (14)	C15—H15A	0.9800
C1—C9	1.4265 (13)	C15—H15B	0.9800
C1—C11	1.5119 (13)	C15—H15C	0.9800
C2—C3	1.4137 (14)	C17—C18	1.5068 (18)
C2—H2	0.9500	C17—H17A	0.9900
C3—C4	1.3694 (14)	C17—H17B	0.9900
C3—H3	0.9500	C18—H18A	0.9800
C4—C10	1.4245 (14)	C18—H18B	0.9800
C4—C16	1.5113 (13)	C18—H18C	0.9800
C5—C6	1.3668 (16)	C19—C20	1.507 (3)
C5—C10	1.4196 (14)	C19—C20'	1.510 (3)
C5—H5	0.9500	C19—H19A	0.9900
C6—C7	1.4116 (16)	C19—H19B	0.9900
C6—H6	0.9500	C20—H20A	0.9800
C7—C8	1.3693 (15)	C20—H20B	0.9800
C7—H7	0.9500	C20—H20C	0.9800
C8—C9	1.4187 (14)	C20'—H20D	0.9800
C8—H8	0.9500	C20'—H20E	0.9800
C9—C10	1.4271 (13)	C20'—H20F	0.9800
C12—C13	1.5083 (17)
C11—N1—C12	124.29 (8)	H13A—C13—H13C	109.5
C11—N1—C14	118.28 (8)	H13B—C13—H13C	109.5
C12—N1—C14	116.57 (8)	N1—C14—C15	110.38 (9)
C16—N2—C17	118.44 (9)	N1—C14—H14A	109.6
C16—N2—C19	124.18 (8)	C15—C14—H14A	109.6
C17—N2—C19	116.68 (9)	N1—C14—H14B	109.6
C2—C1—C9	120.33 (9)	C15—C14—H14B	109.6
C2—C1—C11	120.47 (9)	H14A—C14—H14B	108.1
C9—C1—C11	119.03 (9)	C14—C15—H15A	109.5
C1—C2—C3	120.79 (9)	C14—C15—H15B	109.5
C1—C2—H2	119.6	H15A—C15—H15B	109.5
C3—C2—H2	119.6	C14—C15—H15C	109.5
C4—C3—C2	120.47 (9)	H15A—C15—H15C	109.5
C4—C3—H3	119.8	H15B—C15—H15C	109.5
C2—C3—H3	119.8	O2—C16—N2	122.98 (9)
C3—C4—C10	120.40 (9)	O2—C16—C4	119.54 (9)
C3—C4—C16	119.66 (9)	N2—C16—C4	117.48 (8)
C10—C4—C16	119.84 (9)	N2—C17—C18	111.12 (9)
C6—C5—C10	121.20 (10)	N2—C17—H17A	109.4
C6—C5—H5	119.4	C18—C17—H17A	109.4
C10—C5—H5	119.4	N2—C17—H17B	109.4
C5—C6—C7	120.21 (10)	C18—C17—H17B	109.4
C5—C6—H6	119.9	H17A—C17—H17B	108.0
C7—C6—H6	119.9	C17—C18—H18A	109.5
C8—C7—C6	120.17 (10)	C17—C18—H18B	109.5
C8—C7—H7	119.9	H18A—C18—H18B	109.5
C6—C7—H7	119.9	C17—C18—H18C	109.5
C7—C8—C9	121.13 (10)	H18A—C18—H18C	109.5
C7—C8—H8	119.4	H18B—C18—H18C	109.5
C9—C8—H8	119.4	N2—C19—C20	115.4 (5)
C8—C9—C1	122.48 (9)	N2—C19—C20'	110.8 (5)
C8—C9—C10	118.67 (9)	C20—C19—C20'	15.2 (6)
C1—C9—C10	118.85 (9)	N2—C19—H19A	108.4
C5—C10—C4	122.26 (9)	C20—C19—H19A	108.4
C5—C10—C9	118.61 (9)	C20'—C19—H19A	122.8
C4—C10—C9	119.13 (9)	N2—C19—H19B	108.4
O1—C11—N1	123.01 (9)	C20—C19—H19B	108.4
O1—C11—C1	118.96 (9)	C20'—C19—H19B	97.7
N1—C11—C1	118.02 (8)	H19A—C19—H19B	107.5
N1—C12—C13	113.33 (10)	C19—C20—H20A	109.5
N1—C12—H12A	108.9	C19—C20—H20B	109.5
C13—C12—H12A	108.9	C19—C20—H20C	109.5
N1—C12—H12B	108.9	C19—C20'—H20D	109.5
C13—C12—H12B	108.9	C19—C20'—H20E	109.5
H12A—C12—H12B	107.7	H20D—C20'—H20E	109.5
C12—C13—H13A	109.5	C19—C20'—H20F	109.5
C12—C13—H13B	109.5	H20D—C20'—H20F	109.5
H13A—C13—H13B	109.5	H20E—C20'—H20F	109.5
C12—C13—H13C	109.5
C9—C1—C2—C3	−1.47 (15)	C14—N1—C11—O1	−6.97 (15)
C11—C1—C2—C3	173.66 (9)	C12—N1—C11—C1	3.49 (14)
C1—C2—C3—C4	1.69 (15)	C14—N1—C11—C1	172.50 (9)
C2—C3—C4—C10	−0.22 (15)	C2—C1—C11—O1	−86.37 (12)
C2—C3—C4—C16	176.03 (9)	C9—C1—C11—O1	88.83 (12)
C10—C5—C6—C7	−0.20 (17)	C2—C1—C11—N1	94.14 (11)
C5—C6—C7—C8	0.91 (18)	C9—C1—C11—N1	−90.67 (11)
C6—C7—C8—C9	−0.50 (18)	C11—N1—C12—C13	−107.46 (12)
C7—C8—C9—C1	179.36 (10)	C14—N1—C12—C13	83.36 (12)
C7—C8—C9—C10	−0.59 (16)	C11—N1—C14—C15	−84.26 (12)
C2—C1—C9—C8	179.88 (9)	C12—N1—C14—C15	85.60 (12)
C11—C1—C9—C8	4.68 (14)	C17—N2—C16—O2	−2.88 (16)
C2—C1—C9—C10	−0.16 (14)	C19—N2—C16—O2	−172.93 (10)
C11—C1—C9—C10	−175.37 (8)	C17—N2—C16—C4	177.68 (9)
C6—C5—C10—C4	178.83 (10)	C19—N2—C16—C4	7.63 (15)
C6—C5—C10—C9	−0.88 (15)	C3—C4—C16—O2	−85.72 (12)
C3—C4—C10—C5	178.89 (9)	C10—C4—C16—O2	90.55 (12)
C16—C4—C10—C5	2.65 (14)	C3—C4—C16—N2	93.73 (12)
C3—C4—C10—C9	−1.40 (14)	C10—C4—C16—N2	−90.00 (12)
C16—C4—C10—C9	−177.64 (8)	C16—N2—C17—C18	−84.91 (12)
C8—C9—C10—C5	1.26 (14)	C19—N2—C17—C18	85.89 (12)
C1—C9—C10—C5	−178.69 (9)	C16—N2—C19—C20	−113.5 (4)
C8—C9—C10—C4	−178.46 (9)	C17—N2—C19—C20	76.3 (4)
C1—C9—C10—C4	1.58 (14)	C16—N2—C19—C20'	−97.8 (3)
C12—N1—C11—O1	−175.98 (10)	C17—N2—C19—C20'	92.0 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C15—H15B···Cg^i	0.98	2.78	3.643 (2)	147
C18—H18B···Cg^ii	0.98	2.72	3.586 (2)	148

Symmetry codes: (i) −x+1/2, y+1/2, −z−1/2; (ii) −x+1/2, y+3/2, −z+1/2.