4-Methoxy-N,N′-di­phenyl­benz­amidine

The crystal structure of the title compound, C₂₀H₁₈N₂O, reveals lengthened C=N [1.283 (2) Å] and shortened C—N [1.372 (2) Å] bonds, showing n-π conjugation, which is a feature of amidines. The secondary amino N atom and the phenyl substituent at the C=N double bond are in an E configuration. The mol­ecules are linked into chains by a single N—H...N hydrogen bond parallel to the c axis.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.043
• wR factor = 0.126
• Data-to-parameter ratio = 14.3

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low .......       0.95

Author Response: The data collection was carried out to \O angle of 25.17\% and the value of 0.95 is usual for data set of monoclinic system collected from an CAD4 diffractometer.

Alert level C
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       2.66 Ratio

Author Response: Some C atoms (C13, C14 and C27) have high U~eq~ if compared with others C atoms in the list. It induces a high value of the ratio reported by PLATON.

PLAT241_ALERT_2_C Check High   U(eq) as Compared to Neighbors  for        C13

Author Response: The C atoms, C13 and C14 have high U~eq~, but these atoms belong to aromatic ring and this U~eq~ value does not mean that wrong atom type was assigned.

PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors  for        C11

Author Response: This alert does not proceed. See the U~eq~ list below.

PLAT353_ALERT_3_C Long    N-H Bond (0.87A)   N1     -   H1N    ...       1.02 Ang.

Author Response: This H atom clearly appears as first peak after Fourier difference and it is involved in the intermolecular H-bond.

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 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
   0 ALERT type 4 Improvement, methodology, query or suggestion

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Computing details

Data collection: CAD-4 EXPRESS (Enraf-Nonius, 1994); cell refinement: SET4 in CAD-4 EXPRESS; data reduction: HELENA (Spek, 1996); program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrgia, 1997); software used to prepare material for publication: SHELXL97.

N,N'-Diphenyl-p-methoxybenzamidine

Crystal data

C20H18N2O	F(000) = 640
Mr = 302.36	Dx = 1.210 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 12.547 (2) Å	θ = 6.7–12.3°
b = 14.366 (2) Å	µ = 0.08 mm^−1
c = 9.353 (2) Å	T = 293 K
β = 100.18 (3)°	Irregular block, pale yellow
V = 1659.3 (5) Å^3	0.50 × 0.33 × 0.33 mm
Z = 4

Data collection

Enraf-Nonius CAD-4 diffractometer	Rint = 0.014
Radiation source: fine-focus sealed tube	θmax = 25.2°, θmin = 1.7°
Graphite monochromator	h = −15→0
ω–2θ scans	k = 0→17
3105 measured reflections	l = −11→11
2967 independent reflections	3 standard reflections every 200 reflections
1722 reflections with I > 2σ(I)	intensity decay: 1%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.043	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.126	H-atom parameters constrained
S = 1.01	w = 1/[σ^2(Fo^2) + (0.0602P)^2 + 0.0955P] where P = (Fo^2 + 2Fc^2)/3
2967 reflections	(Δ/σ)max < 0.001
208 parameters	Δρmax = 0.12 e Å^−3
0 restraints	Δρmin = −0.15 e Å^−3

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

	x	y	z	Uiso*/Ueq
O1	0.51070 (14)	0.38603 (13)	0.62867 (16)	0.0961 (6)
N1	0.12717 (12)	0.24289 (11)	0.17425 (16)	0.0578 (4)
H1N	0.1529	0.2143	0.2736	0.069*
N2	0.17796 (13)	0.34772 (12)	0.00978 (17)	0.0577 (4)
C1	0.19161 (14)	0.31309 (14)	0.1381 (2)	0.0505 (5)
C11	0.03523 (15)	0.20072 (16)	0.0918 (2)	0.0584 (5)
C12	0.0008 (2)	0.11935 (19)	0.1450 (3)	0.0918 (8)
H12	0.0382	0.0944	0.2312	0.110*
C13	−0.0896 (3)	0.0743 (3)	0.0705 (4)	0.1280 (12)
H13	−0.1139	0.0200	0.1084	0.154*
C14	−0.1436 (2)	0.1087 (3)	−0.0581 (4)	0.1183 (12)
H14	−0.2032	0.0772	−0.1091	0.142*
C15	−0.10985 (18)	0.1886 (2)	−0.1107 (3)	0.0922 (8)
H15	−0.1466	0.2121	−0.1984	0.111*
C16	−0.02143 (16)	0.23635 (18)	−0.0363 (2)	0.0738 (6)
H16	−0.0002	0.2923	−0.0726	0.089*
C21	0.27810 (15)	0.33797 (12)	0.26275 (18)	0.0480 (5)
C22	0.38611 (15)	0.33305 (15)	0.2520 (2)	0.0598 (5)
H22	0.4052	0.3191	0.1628	0.072*
C23	0.46681 (16)	0.34844 (15)	0.3714 (2)	0.0644 (6)
H23	0.5393	0.3440	0.3626	0.077*
C24	0.43861 (17)	0.37035 (15)	0.5032 (2)	0.0634 (6)
C25	0.33137 (18)	0.37669 (15)	0.5155 (2)	0.0678 (6)
H25	0.3125	0.3923	0.6043	0.081*
C26	0.25212 (16)	0.36000 (13)	0.3974 (2)	0.0578 (5)
H26	0.1798	0.3634	0.4074	0.069*
C27	0.6222 (2)	0.3842 (2)	0.6217 (3)	0.1033 (9)
H27A	0.6636	0.3963	0.7164	0.155*
H27B	0.6378	0.4309	0.5551	0.155*
H27C	0.6410	0.3240	0.5890	0.155*
C31	0.23713 (15)	0.42786 (14)	−0.01706 (18)	0.0534 (5)
C32	0.20181 (18)	0.51541 (16)	0.0154 (2)	0.0694 (6)
H32	0.1417	0.5214	0.0604	0.083*
C33	0.2560 (2)	0.59398 (17)	−0.0189 (2)	0.0805 (7)
H33	0.2320	0.6525	0.0039	0.097*
C34	0.3444 (2)	0.58703 (18)	−0.0861 (2)	0.0774 (7)
H34	0.3809	0.6402	−0.1072	0.093*
C35	0.37821 (18)	0.50090 (17)	−0.1215 (2)	0.0688 (6)
H35	0.4378	0.4954	−0.1677	0.083*
C36	0.32436 (16)	0.42208 (15)	−0.0889 (2)	0.0599 (5)
H36	0.3471	0.3640	−0.1158	0.072*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0888 (12)	0.1339 (15)	0.0563 (10)	−0.0292 (11)	−0.0129 (8)	−0.0083 (9)
N1	0.0519 (9)	0.0719 (11)	0.0474 (9)	−0.0120 (9)	0.0029 (7)	0.0020 (8)
N2	0.0602 (10)	0.0684 (11)	0.0421 (9)	−0.0069 (9)	0.0025 (7)	0.0026 (8)
C1	0.0470 (10)	0.0618 (12)	0.0426 (11)	−0.0001 (10)	0.0075 (8)	−0.0028 (9)
C11	0.0494 (11)	0.0768 (15)	0.0501 (11)	−0.0089 (11)	0.0116 (9)	−0.0135 (11)
C12	0.0960 (18)	0.097 (2)	0.0773 (17)	−0.0382 (16)	0.0001 (14)	−0.0043 (15)
C13	0.132 (3)	0.133 (3)	0.111 (3)	−0.072 (2)	0.003 (2)	−0.012 (2)
C14	0.088 (2)	0.167 (3)	0.094 (2)	−0.054 (2)	0.0015 (17)	−0.038 (2)
C15	0.0561 (14)	0.146 (3)	0.0720 (16)	−0.0122 (16)	0.0032 (12)	−0.0209 (17)
C16	0.0489 (12)	0.1062 (18)	0.0635 (14)	−0.0038 (12)	0.0025 (11)	−0.0053 (13)
C21	0.0543 (11)	0.0510 (11)	0.0382 (10)	−0.0044 (9)	0.0066 (8)	0.0017 (8)
C22	0.0555 (12)	0.0784 (15)	0.0448 (11)	−0.0036 (11)	0.0070 (9)	−0.0007 (10)
C23	0.0524 (12)	0.0789 (15)	0.0593 (13)	−0.0066 (11)	0.0023 (10)	0.0048 (11)
C24	0.0705 (14)	0.0702 (14)	0.0438 (12)	−0.0179 (11)	−0.0048 (10)	0.0015 (10)
C25	0.0808 (15)	0.0807 (16)	0.0416 (11)	−0.0179 (12)	0.0096 (11)	−0.0086 (11)
C26	0.0620 (12)	0.0624 (13)	0.0500 (11)	−0.0078 (10)	0.0132 (10)	−0.0017 (9)
C27	0.0802 (18)	0.116 (2)	0.097 (2)	−0.0152 (16)	−0.0296 (15)	0.0008 (17)
C31	0.0606 (12)	0.0634 (13)	0.0327 (10)	−0.0016 (10)	−0.0013 (9)	0.0013 (9)
C32	0.0814 (15)	0.0739 (16)	0.0547 (13)	0.0084 (13)	0.0166 (12)	−0.0003 (11)
C33	0.111 (2)	0.0605 (15)	0.0694 (15)	0.0082 (14)	0.0150 (14)	−0.0016 (12)
C34	0.0992 (19)	0.0710 (17)	0.0601 (14)	−0.0149 (14)	0.0088 (13)	0.0044 (12)
C35	0.0706 (14)	0.0849 (17)	0.0504 (13)	−0.0103 (13)	0.0088 (11)	0.0021 (11)
C36	0.0669 (13)	0.0648 (14)	0.0469 (11)	−0.0018 (11)	0.0069 (10)	−0.0026 (10)

Geometric parameters (Å, º)

O1—C24	1.368 (2)	C22—H22	0.9300
O1—C27	1.412 (3)	C23—C24	1.378 (3)
N1—C1	1.372 (2)	C23—H23	0.9300
N1—C11	1.407 (2)	C24—C25	1.374 (3)
N1—H1N	1.0148	C25—C26	1.370 (3)
N2—C1	1.283 (2)	C25—H25	0.9300
N2—C31	1.416 (2)	C26—H26	0.9300
C1—C21	1.489 (2)	C27—H27A	0.9600
C11—C12	1.370 (3)	C27—H27B	0.9600
C11—C16	1.379 (3)	C27—H27C	0.9600
C12—C13	1.383 (4)	C31—C36	1.385 (3)
C12—H12	0.9300	C31—C32	1.385 (3)
C13—C14	1.364 (4)	C32—C33	1.384 (3)
C13—H13	0.9300	C32—H32	0.9300
C14—C15	1.347 (4)	C33—C34	1.372 (3)
C14—H14	0.9300	C33—H33	0.9300
C15—C16	1.383 (3)	C34—C35	1.368 (3)
C15—H15	0.9300	C34—H34	0.9300
C16—H16	0.9300	C35—C36	1.380 (3)
C21—C22	1.378 (2)	C35—H35	0.9300
C21—C26	1.392 (2)	C36—H36	0.9300
C22—C23	1.386 (3)
C24—O1—C27	117.88 (19)	C22—C23—H23	120.3
C1—N1—C11	130.0 (2)	O1—C24—C25	115.20 (19)
C1—N1—H1N	114.7	O1—C24—C23	124.7 (2)
C11—N1—H1N	115.1	C25—C24—C23	120.06 (18)
C1—N2—C31	119.6 (2)	C26—C25—C24	120.17 (19)
N2—C1—N1	121.9 (2)	C26—C25—H25	119.9
N2—C1—C21	126.7 (2)	C24—C25—H25	119.9
N1—C1—C21	111.3 (2)	C25—C26—C21	121.09 (19)
C12—C11—C16	119.0 (2)	C25—C26—H26	119.5
C12—C11—N1	116.7 (2)	C21—C26—H26	119.5
C16—C11—N1	124.3 (2)	O1—C27—H27A	109.5
C11—C12—C13	119.9 (3)	O1—C27—H27B	109.5
C11—C12—H12	120.0	H27A—C27—H27B	109.5
C13—C12—H12	120.0	O1—C27—H27C	109.5
C14—C13—C12	120.7 (3)	H27A—C27—H27C	109.5
C14—C13—H13	119.6	H27B—C27—H27C	109.5
C12—C13—H13	119.6	C36—C31—C32	118.16 (19)
C15—C14—C13	119.4 (3)	C36—C31—N2	121.44 (18)
C15—C14—H14	120.3	C32—C31—N2	120.09 (18)
C13—C14—H14	120.3	C33—C32—C31	120.0 (2)
C14—C15—C16	121.0 (3)	C33—C32—H32	120.0
C14—C15—H15	119.5	C31—C32—H32	120.0
C16—C15—H15	119.5	C34—C33—C32	121.1 (2)
C11—C16—C15	119.8 (3)	C34—C33—H33	119.4
C11—C16—H16	120.1	C32—C33—H33	119.4
C15—C16—H16	120.1	C35—C34—C33	119.2 (2)
C22—C21—C26	117.92 (17)	C35—C34—H34	120.4
C22—C21—C1	121.36 (16)	C33—C34—H34	120.4
C26—C21—C1	120.53 (17)	C34—C35—C36	120.3 (2)
C21—C22—C23	121.37 (19)	C34—C35—H35	119.9
C21—C22—H22	119.3	C36—C35—H35	119.9
C23—C22—H22	119.3	C35—C36—C31	121.2 (2)
C24—C23—C22	119.38 (19)	C35—C36—H36	119.4
C24—C23—H23	120.3	C31—C36—H36	119.4

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1N···N2^i	1.01	2.35	3.353 (2)	169

Symmetry code: (i) x, −y+1/2, z+1/2.