4-[2-Methyl-4-(4-methyl­phenyl­diazen­yl)phen­oxy]phthalonitrile

The title compound, C₂₂H₁₆N₄O, displays a trans configuration with respect to the –N=N– double bond, as found for other diazene derivatives. There is a weak intra­molecular C—H...N hydrogen bond, which seems to have an effect on the mol­ecular conformation. The crystal packing is governed by weak inter­molecular C—H...N and C—H...O hydrogen bonds, and weak C—H...π stacking.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.053
• wR factor = 0.156
• Data-to-parameter ratio = 16.7

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT026_ALERT_3_C Ratio Observed / Unique Reflections too Low ....         47 Perc.
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C9     -   C14     ..       5.76 su
PLAT230_ALERT_2_C Hirshfeld Test Diff for    C11    -   C12     ..       5.10 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        C21
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C5     -   C8     ...       1.43 Ang.
PLAT371_ALERT_2_C Long   C(sp2)-C(sp1) Bond  C6     -   C7     ...       1.43 Ang.
PLAT380_ALERT_4_C Check Incorrectly? Oriented X(sp2)-Methyl Moiety        C22
PLAT480_ALERT_4_C Long H...A H-Bond Reported H15A   ..  N2      ..       2.71 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H17    ..  N2      ..       2.79 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H22A   ..  O1      ..       2.90 Ang.
PLAT482_ALERT_4_C Small D-H..A Angle Rep for C19    ..  N3      ..      95.00 Deg.
PLAT717_ALERT_1_C D...A   Unknown or Inconsistent Label ..........         G2

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

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

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S1. Comment

4-[2-Methyl-4-(4-methylphenyldiazenyl)phenoxy]phtalonitrile, (I), is a starting material in the synthesis of network polymeric phthalocyanines and high-performance aromatic polymers (McKeown, 1998; Takekoshi, 1987). In addition to their extensive use as dyes and pigments, phthalocyanines have found widespread applications in catalysis, optical recording, photoconductive materials, photodynamic theraphy and as chemical sensors (Leznoff & Lever, 1989–1996).

Polymeric phthalocyanines have been known for their use as dyes and industrial high-technology materials and are also of additional interest because of their high thermostability (Leznoff & Lever, 1989–1996). Azo compounds have been the most widely used class of dyes owing to their versatile applications in various fields, such as dyeing textile fibres, colouring different materials, plastics, biological medical studies, lasers, liquid crystalline displays, electrooptical devices and ink-jet printers in high-technology areas (Catino & Farris, 1985; Gregory, 1991). The azo compound class accounts for 60–70% of all dyes. The geometric isomerism of azo compounds is known to exist in two forms, viz. cis and trans. A change from trans to cis can be effected by exposure to UV radiation, which can lead to photochromism. Photochromic compounds are of great interest for the control and measurement of radiation intensity, optical computers and display systems (Dürr & Bouas-Laurent, 1990). Photochromic materials of this type are of interest for potential applications in molecular electronic devices (Martin et al., 1995), among others.

The molecular structure of (I) is shown in Fig. 1, with the atom-numbering scheme. Selected bond distances and angles are given in Table 1. The phenyl rings C9–C14 and C16–C21 adopt trans configurations about the azo funtional group, as observed in crystals of other azo compounds. The N3—C10 and N4—C18 bond lengths of 1.459 (3) and 1.449 (3) Å, respectively, indicate single-bond character, and the –N═N– bond length of 1.218 (3) Å is indicative of significant double-bond character. Similar values for corresponding bond distances and angles have been observed in related trans-azo compounds (Alder et al., 1999, 2001; Dimmock et al., 1997; Ersanlı et al., 2004; Koşar et al., 2004). The dihedral angles between the mean planes of the C9–C14 and C16–C21 phenyls rings and the C18—N4═N3—C10 azo bridge are 13.59 (9) and 33.3 (5)°, respectively. The C1—C2—O1—C13 and C10—N3—N4—C18 torsion angles are 145.4 (2) and -179.15 (18)°, respectively. The dihedral angles between rings A (C1–C6), B (C9–C14) and C (C16–C21) are A/B = 88.39 (6)°, A/C = 88.39 (6)° and B/C = 13.09 (14)°. The intramolecular C—H···N hydrogen bonds (Table 2) seem to affect the molecular conformation (Fig. 1). The molecules are linked by intermolecular C—H···N and C—H···O hydrogen bonds, and C—H···π interactions (Table 2), forming a three-dimensional network. In Table 2, Cg2 is the centroid of ring B. The C19—H19···N3 hydrogen-bonded ring is coplanar with the adjacent ring, with a C19—C18—N4—N3 torsion angle of 0.32 (34) Å.

S2. Experimental

A mixture of 4-methylaniline (2.84 g, 26 mmol), water (50 ml) and concentrated hydrochloric acid (6.6 ml, 79 mmol) was stirred until a clear solution was obtained. This solution was cooled to 273–278 K and a solution of nitrite (2.5 g, 36.4 mmol) in water was added dropwise while the temperature was maintained below 278 K. The resulting mixture was stirred for 30 min in an ice bath. o-Cresol (3.9 g, 36.4 mmol) solution (pH 9) was added gradually to a cooled solution of 4-methylbenzenediazonium chloride, prepared as described above, and the resulting mixture was stirred at 273–278 K for 60 min in an ice bath. The product was recrystallized from ethanol to obtain solid 2-methyl-4- (4-methylphenylazo)phenol (yield 84%, m.p. 441–443 K). To a solution of the solid (3.74 g, 16.5 mmol) in dimethylformamide (DMF) was added potasium carbonate (3.43 g, 33 mmol). The mixture was stirred for 30 min under N₂. 4-Nitrophtalonitrile solution in DMF was added. The mixture was stirred for 48 h at 323 K under N₂ and poured into ice-water (150 g). The product was filtered off and washed with water. The product was recrystallized from ethanol to obtain solid (I). Crystals of (I) were obtained from an ethanol/CCl4 (1:2) mixture at room temparature via slow evaporation (yield 68%, m.p. 424–426 K).

S3. Refinement

The H atoms of atoms C19 and C22 were positioned geometrically at distances of 0.93 and 0.96 Å, respectively, from the parent C atoms; a riding model was used and U_iso(H) values were constrained to be 1.2 and 1.5 times U_eq(C), respectively. The other H atoms were located in a difference Fourier map and refined freely [CH C—H = 0.88 (3)–1.07 (3) Å, CH₃ C—H = 0.94 (4)–0.97 (3) Å and U_iso(H) = 0.062 (6)–0.114 (12) Ų]. Please check changes to first sentence.

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

Fig. 1. An ORTEP-3 (Farrugia, 1997) drawing of the title molecule, with the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The intramolecular hydrogen bond is indicated by dashed lines.

4-[2-Methyl-4-(4-methylphenyldiazenyl)phenoxy]phtalonitrile

Crystal data

C22H16N4O	F(000) = 736
Mr = 352.39	Dx = 1.290 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -p 2ybc	Cell parameters from 13869 reflections
a = 12.7084 (10) Å	θ = 1.8–27.9°
b = 8.0446 (9) Å	µ = 0.08 mm^−1
c = 20.2971 (16) Å	T = 296 K
β = 119.050 (5)°	Prism., brown
V = 1814.0 (3) Å^3	0.43 × 0.30 × 0.14 mm
Z = 4

Data collection

Stoe IPDS-2 diffractometer	4285 independent reflections
Radiation source: sealed X-ray tube	1998 reflections with I > 2σ(I)
Plane graphite monochromator	Rint = 0.059
Detector resolution: 6.67 pixels mm^-1	θmax = 27.8°, θmin = 1.8°
rotation method scans	h = −16→16
Absorption correction: integration (X-RED; Stoe & Cie, 2002)	k = −10→10
Tmin = 0.964, Tmax = 0.990	l = −24→26
17432 measured reflections

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)] = 0.053	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.157	H atoms treated by a mixture of independent and constrained refinement
S = 0.91	w = 1/[σ^2(Fo^2) + (0.0805P)^2] where P = (Fo^2 + 2Fc^2)/3
4285 reflections	(Δ/σ)max < 0.001
256 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.21 e Å^−3

Special details

Experimental. 215 frames, detector distance = 100 mm

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	0.3345 (2)	0.3867 (3)	0.23129 (13)	0.0569 (6)
C2	0.22959 (19)	0.4437 (3)	0.22799 (12)	0.0507 (5)
C3	0.1716 (2)	0.5822 (3)	0.18615 (13)	0.0553 (6)
C4	0.2187 (2)	0.6653 (3)	0.14674 (13)	0.0567 (6)
C5	0.32372 (19)	0.6113 (3)	0.14962 (12)	0.0545 (4)
C6	0.38272 (19)	0.4719 (3)	0.19314 (11)	0.0521 (5)
C7	0.4958 (2)	0.4225 (3)	0.19989 (14)	0.0678 (7)
C8	0.3745 (2)	0.6987 (3)	0.11033 (12)	0.0545 (4)
C9	0.1391 (2)	0.6045 (3)	0.39910 (15)	0.0614 (3)
C10	0.0191 (2)	0.5799 (3)	0.37385 (13)	0.0614 (3)
C11	−0.0488 (2)	0.4847 (3)	0.31002 (13)	0.0614 (3)
C12	0.0079 (2)	0.4130 (3)	0.27338 (15)	0.0608 (6)
C13	0.1288 (2)	0.4377 (3)	0.30063 (12)	0.0524 (5)
C14	0.1985 (2)	0.5340 (3)	0.36421 (12)	0.0541 (5)
C15	0.3310 (2)	0.5592 (5)	0.39446 (18)	0.0699 (7)
C16	−0.3294 (2)	0.7384 (4)	0.47598 (15)	0.0701 (7)
C17	−0.2813 (2)	0.6619 (3)	0.43649 (15)	0.0660 (3)
C18	−0.1680 (2)	0.7045 (3)	0.45024 (14)	0.0660 (3)
C19	−0.1054 (2)	0.8267 (3)	0.50270 (14)	0.0660 (3)
H19	−0.0292	0.8583	0.5117	0.079*
C20	−0.1564 (2)	0.9020 (4)	0.54192 (16)	0.0716 (7)
C21	−0.2688 (2)	0.8579 (3)	0.52950 (14)	0.0608 (6)
C22	−0.3226 (3)	0.9391 (4)	0.57321 (17)	0.0913 (9)
H22A	−0.2717	0.9188	0.6261	0.137*
H22B	−0.4010	0.8934	0.5575	0.137*
H22C	−0.3292	1.0566	0.5639	0.137*
N1	0.5869 (2)	0.3875 (4)	0.20607 (14)	0.0996 (9)
N2	0.4172 (2)	0.7694 (3)	0.08035 (13)	0.0838 (7)
N3	−0.02561 (18)	0.6637 (2)	0.41914 (11)	0.0614 (3)
N4	−0.12549 (18)	0.6172 (3)	0.40522 (11)	0.0660 (3)
O1	0.18625 (14)	0.35213 (18)	0.26680 (9)	0.0622 (4)
H1	0.374 (2)	0.291 (3)	0.2605 (14)	0.077 (8)*
H3	0.101 (2)	0.615 (3)	0.1860 (13)	0.066 (7)*
H4	0.1753 (19)	0.762 (3)	0.1166 (12)	0.062 (6)*
H9	0.183 (2)	0.675 (3)	0.4420 (15)	0.087 (8)*
H11	−0.140 (2)	0.467 (3)	0.2877 (13)	0.077 (7)*
H12	−0.034 (2)	0.355 (3)	0.2301 (14)	0.068 (7)*
H15A	0.367 (2)	0.606 (3)	0.4437 (16)	0.083 (8)*
H15B	0.367 (3)	0.462 (4)	0.3897 (18)	0.114 (12)*
H15C	0.348 (2)	0.640 (4)	0.3650 (15)	0.083 (8)*
H16	−0.410 (3)	0.707 (3)	0.4649 (15)	0.092 (9)*
H17	−0.327 (3)	0.567 (4)	0.3954 (17)	0.109 (10)*
H20	−0.120 (3)	0.980 (4)	0.5761 (16)	0.089 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0664 (15)	0.0519 (13)	0.0550 (13)	0.0111 (11)	0.0315 (12)	0.0057 (11)
C2	0.0605 (13)	0.0474 (12)	0.0490 (12)	−0.0029 (10)	0.0304 (10)	−0.0055 (10)
C3	0.0551 (14)	0.0561 (14)	0.0582 (13)	0.0045 (11)	0.0303 (11)	−0.0010 (11)
C4	0.0565 (13)	0.0579 (14)	0.0553 (13)	0.0100 (11)	0.0269 (11)	0.0083 (12)
C5	0.0544 (9)	0.0572 (9)	0.0499 (9)	0.0023 (7)	0.0236 (7)	−0.0003 (7)
C6	0.0536 (12)	0.0576 (13)	0.0455 (11)	0.0041 (10)	0.0244 (10)	−0.0045 (10)
C7	0.0661 (16)	0.0763 (17)	0.0651 (15)	0.0178 (13)	0.0352 (13)	0.0157 (13)
C8	0.0544 (9)	0.0572 (9)	0.0499 (9)	0.0023 (7)	0.0236 (7)	−0.0003 (7)
C9	0.0650 (7)	0.0612 (7)	0.0631 (7)	0.0025 (5)	0.0352 (6)	0.0072 (5)
C10	0.0650 (7)	0.0612 (7)	0.0631 (7)	0.0025 (5)	0.0352 (6)	0.0072 (5)
C11	0.0650 (7)	0.0612 (7)	0.0631 (7)	0.0025 (5)	0.0352 (6)	0.0072 (5)
C12	0.0673 (16)	0.0566 (14)	0.0576 (14)	−0.0113 (12)	0.0296 (13)	−0.0030 (12)
C13	0.0658 (14)	0.0450 (12)	0.0565 (13)	0.0001 (10)	0.0376 (11)	0.0019 (10)
C14	0.0610 (13)	0.0521 (13)	0.0534 (12)	0.0024 (10)	0.0311 (11)	0.0041 (11)
C15	0.0652 (17)	0.081 (2)	0.0655 (17)	−0.0109 (15)	0.0337 (14)	−0.0101 (16)
C16	0.0609 (16)	0.0806 (18)	0.0762 (17)	−0.0056 (14)	0.0391 (14)	0.0121 (15)
C17	0.0628 (7)	0.0707 (8)	0.0676 (7)	0.0009 (6)	0.0340 (6)	0.0070 (6)
C18	0.0628 (7)	0.0707 (8)	0.0676 (7)	0.0009 (6)	0.0340 (6)	0.0070 (6)
C19	0.0628 (7)	0.0707 (8)	0.0676 (7)	0.0009 (6)	0.0340 (6)	0.0070 (6)
C20	0.0653 (16)	0.0819 (19)	0.0678 (16)	0.0001 (14)	0.0325 (14)	−0.0090 (15)
C21	0.0603 (14)	0.0690 (15)	0.0625 (14)	0.0119 (12)	0.0371 (12)	0.0143 (13)
C22	0.094 (2)	0.103 (2)	0.100 (2)	0.0238 (17)	0.0651 (18)	0.0107 (18)
N1	0.0790 (16)	0.131 (2)	0.1020 (19)	0.0390 (15)	0.0541 (15)	0.0358 (17)
N2	0.0827 (15)	0.0904 (17)	0.0904 (16)	0.0066 (13)	0.0515 (14)	0.0230 (14)
N3	0.0650 (7)	0.0612 (7)	0.0631 (7)	0.0025 (5)	0.0352 (6)	0.0072 (5)
N4	0.0628 (7)	0.0707 (8)	0.0676 (7)	0.0009 (6)	0.0340 (6)	0.0070 (6)
O1	0.0824 (11)	0.0494 (9)	0.0731 (11)	−0.0022 (8)	0.0522 (10)	−0.0036 (8)

Geometric parameters (Å, º)

C1—C6	1.380 (3)	C13—C14	1.393 (3)
C1—C2	1.380 (3)	C13—O1	1.402 (3)
C1—H1	0.95 (3)	C14—C15	1.500 (3)
C2—O1	1.374 (3)	C15—H15A	0.95 (3)
C2—C3	1.377 (3)	C15—H15B	0.94 (4)
C3—C4	1.382 (3)	C15—H15C	0.97 (3)
C3—H3	0.93 (2)	C16—C17	1.368 (4)
C4—C5	1.378 (3)	C16—C21	1.373 (4)
C4—H4	0.98 (2)	C16—H16	0.97 (3)
C5—C6	1.399 (3)	C17—C18	1.370 (3)
C5—C8	1.431 (3)	C17—H17	1.07 (3)
C6—C7	1.432 (3)	C18—C19	1.382 (4)
C7—N1	1.138 (3)	C18—N4	1.449 (3)
C8—N2	1.144 (3)	C19—C20	1.386 (4)
C9—C10	1.367 (3)	C19—H19	0.9300
C9—C14	1.383 (3)	C20—C21	1.372 (4)
C9—H9	0.96 (3)	C20—H20	0.88 (3)
C10—C11	1.387 (3)	C21—C22	1.506 (3)
C10—N3	1.459 (3)	C22—H22A	0.9600
C11—C12	1.388 (3)	C22—H22B	0.9600
C11—H11	1.02 (2)	C22—H22C	0.9600
C12—C13	1.371 (3)	N3—N4	1.218 (3)
C12—H12	0.90 (2)
C6—C1—C2	119.3 (2)	C9—C14—C15	121.2 (2)
C6—C1—H1	120.7 (15)	C13—C14—C15	122.5 (2)
C2—C1—H1	120.0 (15)	C14—C15—H15A	110.7 (16)
O1—C2—C3	122.9 (2)	C14—C15—H15B	110 (2)
O1—C2—C1	116.1 (2)	H15A—C15—H15B	116 (3)
C3—C2—C1	120.9 (2)	C14—C15—H15C	111.9 (16)
C2—C3—C4	119.7 (2)	H15A—C15—H15C	104 (2)
C2—C3—H3	117.2 (15)	H15B—C15—H15C	104 (3)
C4—C3—H3	123.1 (15)	C17—C16—C21	122.6 (2)
C5—C4—C3	120.4 (2)	C17—C16—H16	117.9 (16)
C5—C4—H4	121.1 (13)	C21—C16—H16	119.4 (16)
C3—C4—H4	118.5 (13)	C16—C17—C18	119.6 (3)
C4—C5—C6	119.4 (2)	C16—C17—H17	123.0 (16)
C4—C5—C8	120.8 (2)	C18—C17—H17	117.4 (16)
C6—C5—C8	119.8 (2)	C17—C18—C19	119.3 (2)
C1—C6—C5	120.3 (2)	C17—C18—N4	115.3 (2)
C1—C6—C7	120.5 (2)	C19—C18—N4	125.4 (2)
C5—C6—C7	119.2 (2)	C18—C19—C20	119.9 (2)
N1—C7—C6	178.1 (3)	C18—C19—H19	120.0
N2—C8—C5	178.6 (3)	C20—C19—H19	120.0
C10—C9—C14	122.4 (2)	C21—C20—C19	121.1 (3)
C10—C9—H9	118.8 (16)	C21—C20—H20	115.8 (19)
C14—C9—H9	118.8 (16)	C19—C20—H20	123.0 (19)
C9—C10—C11	120.3 (2)	C20—C21—C16	117.4 (2)
C9—C10—N3	113.7 (2)	C20—C21—C22	120.7 (3)
C11—C10—N3	126.0 (2)	C16—C21—C22	121.9 (2)
C10—C11—C12	118.7 (2)	C21—C22—H22A	109.5
C10—C11—H11	123.2 (13)	C21—C22—H22B	109.5
C12—C11—H11	118.1 (14)	H22A—C22—H22B	109.5
C13—C12—C11	119.7 (2)	C21—C22—H22C	109.5
C13—C12—H12	118.8 (15)	H22A—C22—H22C	109.5
C11—C12—H12	121.4 (15)	H22B—C22—H22C	109.5
C12—C13—C14	122.6 (2)	N4—N3—C10	113.1 (2)
C12—C13—O1	118.6 (2)	N3—N4—C18	111.7 (2)
C14—C13—O1	118.59 (19)	C2—O1—C13	117.82 (17)
C9—C14—C13	116.3 (2)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C19—H19···N3	0.93	2.46	2.701 (3)	95
C15—H15A···N2^i	0.96 (3)	2.71 (3)	3.649 (4)	166 (2)
C17—H17···N2^ii	1.07 (3)	2.79 (3)	3.534 (4)	127 (2)
C22—H22A···O1^iii	0.96	2.90	3.684 (3)	140
C12—H12···Cg2^ii	0.90 (2)	3.03 (2)	3.796 (3)	144.2 (19)

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