N,N′-Di-1-naphthyl­urea revisited

The mol­ecule of the title compound, C₂₁H₁₆N₂O, has crystallographic twofold rotation symmetry, with the C=O group lying on the rotation axis. Inter­molecular N—H...O hydrogen bonds result in a chain structure containing R₂¹(6) loops. This ortho­rhom­bic structure probably represents a correction of a previous study where space group P2₁ was found [Kurth & Lewis (2003), J. Am. Chem. Soc. 125, 13760–13767].

Key indicators

• Single-crystal X-ray study
• T = 93 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.059
• wR factor = 0.150
• Data-to-parameter ratio = 7.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT024_ALERT_4_B Merging of Friedel Pairs is STRONGLY Indicated .          !

Alert level C
PLAT066_ALERT_1_C Predicted and Reported Transmissions Identical .          ?
PLAT089_ALERT_3_C Poor Data / Parameter Ratio (Zmax .LT. 18) .....       7.62
PLAT340_ALERT_3_C Low Bond Precision on C-C bonds (x 1000) Ang ...          5

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           25.30
           From the CIF: _reflns_number_total                869
           Count of symmetry unique reflns          866
           Completeness (_total/calc)            100.35%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured         3
           Fraction of Friedel pairs measured     0.003
           Are heavy atom types Z>Si present         no

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

   1 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 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
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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Computing details

Data collection: CrystalClear (Rigaku, 2004); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97.

N,N'-Di-1-naphthylurea

Crystal data

C21H16N2O	F(000) = 328
Mr = 312.36	Dx = 1.341 Mg m^−3
Orthorhombic, P21212	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2 2ab	Cell parameters from 2325 reflections
a = 11.284 (3) Å	θ = 2.3–28.6°
b = 14.918 (4) Å	µ = 0.08 mm^−1
c = 4.5942 (11) Å	T = 93 K
V = 773.4 (3) Å^3	Plate, colourless
Z = 2	0.20 × 0.10 × 0.01 mm

Data collection

Rigaku Mercury CCD area-detector diffractometer	869 independent reflections
Radiation source: rotating anode	761 reflections with I > 2σ(I)
Confocal monochromator	Rint = 0.060
ω and φ scans	θmax = 25.3°, θmin = 2.3°
Absorption correction: multi-scan (CrystalClear; Rigaku, 2004)	h = −9→13
Tmin = 0.983, Tmax = 0.999	k = −16→17
5088 measured reflections	l = −5→4

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)] = 0.059	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.150	w = 1/[σ^2(Fo^2) + (0.0791P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.14	(Δ/σ)max < 0.001
869 reflections	Δρmax = 0.24 e Å^−3
114 parameters	Δρmin = −0.25 e Å^−3
0 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: 0.070 (15)

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
C1	0.6716 (3)	0.7006 (2)	0.6915 (7)	0.0246 (8)
C2	0.5921 (3)	0.7396 (2)	0.4898 (8)	0.0275 (8)
H2	0.5284	0.7049	0.4156	0.033*
C3	0.6055 (4)	0.8270 (3)	0.3991 (8)	0.0319 (10)
H3	0.5513	0.8521	0.2635	0.038*
C4	0.6994 (3)	0.8789 (2)	0.5076 (8)	0.0327 (10)
H4	0.7090	0.9391	0.4440	0.039*
C5	0.7769 (3)	0.8435 (2)	0.7034 (8)	0.0296 (9)
H5	0.8401	0.8794	0.7748	0.036*
C6	0.7652 (3)	0.7541 (2)	0.8026 (7)	0.0267 (9)
C7	0.8438 (3)	0.7180 (2)	1.0123 (8)	0.0294 (9)
H7	0.9061	0.7540	1.0875	0.035*
C8	0.8308 (3)	0.6315 (3)	1.1078 (8)	0.0308 (9)
H8	0.8829	0.6082	1.2515	0.037*
C9	0.7400 (4)	0.5772 (2)	0.9923 (7)	0.0285 (9)
H9	0.7328	0.5167	1.0549	0.034*
C10	0.6616 (3)	0.6106 (2)	0.7900 (7)	0.0271 (9)
C11	0.5000	0.5000	0.8258 (10)	0.0248 (11)
N1	0.5714 (3)	0.5545 (2)	0.6675 (6)	0.0262 (8)
H1	0.560 (3)	0.552 (3)	0.485 (8)	0.031*
O1	0.5000	0.5000	1.0979 (6)	0.0287 (9)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.026 (2)	0.0235 (18)	0.0242 (16)	−0.0006 (15)	0.0031 (15)	−0.0008 (14)
C2	0.0290 (19)	0.0256 (19)	0.0279 (18)	−0.0040 (15)	0.0004 (15)	−0.0007 (15)
C3	0.032 (2)	0.029 (2)	0.034 (2)	−0.0013 (16)	−0.0008 (17)	0.0036 (16)
C4	0.033 (2)	0.0241 (19)	0.041 (2)	−0.0017 (16)	0.0038 (17)	0.0005 (17)
C5	0.028 (2)	0.027 (2)	0.034 (2)	−0.0039 (16)	0.0028 (17)	−0.0048 (16)
C6	0.0245 (19)	0.0271 (19)	0.0285 (17)	−0.0009 (16)	0.0035 (15)	−0.0024 (15)
C7	0.0244 (19)	0.030 (2)	0.0336 (19)	−0.0060 (16)	0.0003 (17)	−0.0068 (16)
C8	0.029 (2)	0.036 (2)	0.0274 (18)	0.0003 (17)	−0.0061 (16)	−0.0007 (16)
C9	0.033 (2)	0.0246 (18)	0.0277 (18)	0.0011 (16)	0.0031 (16)	0.0032 (15)
C10	0.027 (2)	0.0280 (19)	0.0259 (18)	−0.0030 (16)	0.0056 (17)	−0.0016 (15)
C11	0.022 (3)	0.021 (2)	0.032 (3)	0.000 (2)	0.000	0.000
N1	0.0272 (18)	0.0292 (16)	0.0223 (14)	−0.0098 (15)	0.0005 (12)	−0.0006 (13)
O1	0.032 (2)	0.031 (2)	0.0225 (17)	−0.0053 (16)	0.000	0.000

Geometric parameters (Å, º)

C1—C2	1.415 (5)	C7—C8	1.371 (5)
C1—C6	1.419 (5)	C7—H7	0.9500
C1—C10	1.422 (5)	C8—C9	1.410 (5)
C2—C3	1.377 (5)	C8—H8	0.9500
C2—H2	0.9500	C9—C10	1.376 (5)
C3—C4	1.404 (5)	C9—H9	0.9500
C3—H3	0.9500	C10—N1	1.433 (5)
C4—C5	1.362 (5)	C11—O1	1.250 (6)
C4—H4	0.9500	C11—N1^i	1.356 (4)
C5—C6	1.414 (5)	C11—N1	1.356 (4)
C5—H5	0.9500	N1—H1	0.85 (4)
C6—C7	1.416 (5)
C2—C1—C6	118.4 (3)	C8—C7—C6	120.6 (3)
C2—C1—C10	123.1 (3)	C8—C7—H7	119.7
C6—C1—C10	118.5 (3)	C6—C7—H7	119.7
C3—C2—C1	121.2 (3)	C7—C8—C9	119.9 (3)
C3—C2—H2	119.4	C7—C8—H8	120.1
C1—C2—H2	119.4	C9—C8—H8	120.1
C2—C3—C4	119.8 (4)	C10—C9—C8	120.9 (3)
C2—C3—H3	120.1	C10—C9—H9	119.6
C4—C3—H3	120.1	C8—C9—H9	119.6
C5—C4—C3	120.4 (3)	C9—C10—C1	120.4 (3)
C5—C4—H4	119.8	C9—C10—N1	120.7 (3)
C3—C4—H4	119.8	C1—C10—N1	118.9 (3)
C4—C5—C6	121.2 (3)	O1—C11—N1^i	122.4 (2)
C4—C5—H5	119.4	O1—C11—N1	122.4 (2)
C6—C5—H5	119.4	N1^i—C11—N1	115.1 (4)
C5—C6—C7	121.3 (3)	C11—N1—C10	124.2 (3)
C5—C6—C1	118.9 (3)	C11—N1—H1	115 (3)
C7—C6—C1	119.8 (3)	C10—N1—H1	121 (3)
C6—C1—C2—C3	0.9 (5)	C6—C7—C8—C9	1.3 (5)
C10—C1—C2—C3	−179.7 (3)	C7—C8—C9—C10	−1.8 (5)
C1—C2—C3—C4	0.0 (5)	C8—C9—C10—C1	0.6 (5)
C2—C3—C4—C5	−0.4 (6)	C8—C9—C10—N1	178.3 (3)
C3—C4—C5—C6	0.0 (5)	C2—C1—C10—C9	−178.3 (3)
C4—C5—C6—C7	−178.2 (3)	C6—C1—C10—C9	1.1 (5)
C4—C5—C6—C1	0.9 (5)	C2—C1—C10—N1	3.9 (5)
C2—C1—C6—C5	−1.3 (5)	C6—C1—C10—N1	−176.6 (3)
C10—C1—C6—C5	179.2 (3)	O1—C11—N1—C10	6.5 (4)
C2—C1—C6—C7	177.9 (3)	N1^i—C11—N1—C10	−173.5 (4)
C10—C1—C6—C7	−1.7 (5)	C9—C10—N1—C11	47.2 (5)
C5—C6—C7—C8	179.5 (3)	C1—C10—N1—C11	−135.1 (3)
C1—C6—C7—C8	0.4 (5)

Symmetry code: (i) −x+1, −y+1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1^ii	0.85 (4)	2.06 (4)	2.856 (4)	157 (4)

Symmetry code: (ii) x, y, z−1.