6,6-Diisopropyl-3,3′-dimethyl-2,2′-azinodiphenol

In the centrosymmetric title compound, C₂₂H₂₈N₂O₂, the H atom of the phenol OH group forms a strong intra­molecular O—H...N hydrogen bond, with an O...N distance of 2.578 (2) Å, which is in the middle of the expected range for such hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.059
• wR factor = 0.181
• Data-to-parameter ratio = 15.3

checkCIF/PLATON results

No syntax errors found



Alert level B
ABSTM02_ALERT_3_B  The ratio of expected to reported Tmax/Tmin(RR') is < 0.75
            Tmin and Tmax reported:      0.330     0.758
            Tmin(prime) and Tmax expected:      0.672     0.943
            RR(prime) =      0.611
            Please check that your absorption correction is appropriate.
PLAT061_ALERT_3_B Tmax/Tmin Range Test RR' too Large .............       0.56

Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       1.24

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      1.244
            Tmax scaled      0.943 Tmin scaled      0.411
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K

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

   2 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
   3 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

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S1. Comment

Hydrazides have interesting ligational properties due to presence of several potential coordination sites and transitional metal complexes of this ligand have been studied (Rastogi et al., 1979; Pelizzi & Pelizzi, 1980). Selection of the title compound was based on its broad spectrum activity and important role in plants as well as natural occurrence of the parent compound thymol (2-hydroxy-3-isopropyl-6-methylbenzene) (Kumbhar & Dewang, 2001). Hydrazones are a class of compounds obtained by condensation of aldehyde or ketone with appropriate amines. The types of hydrazone produced depend upon the amines used and may include simple amines like aniline or hydrazine. When the terminal NH₂ group is condensed with aldehydes or ketones, the proton of NH group become more labile and acyl hydrazones react with metal ions in the enol form (Satapathy & Sahoo, 1970; Yamada et al., 1968; Sinn & Harris, 1969).

Elemental analysis of title compound gave a satisfactory fit to the formula C₂₂H₂₈N₂O₂. Table 1 contains selected bond lengths and angles. Views of the molecule and unit-cell contents are shown in Figs 1 and 2 respectively.

Hydrogen bonding is major feature of the structure of phenolic hydrazines. Invariably, the phenolic H atom forms an intramolecular hydrogen bond to the N atom of hydrazine group, giving a six membered ring. This interaction is usually characterized in terms of phenolic O to hydrazine N separation. This distance varies little between structures, with maximum value of 2.65 Å and minimum of 2.51 Å. In all free ligand structures, the molecules associate via intramolecular hydrogen bonding.

The structure of the title compound C₂₂H₂₈N₂O₂ exhibits intramolecular hydrogen bonding (Table 2) where the H atom of the phenolic hydroxyl group forms a strong O—H······N intramolecular hydrogen bond with an O···.N distance 2.578 (2)Å which is in the middle of expected range of such hydrogen bonds.

Related literature

For related literature, see: Kumbhar & Dewang (2001); Pelizzi & Pelizzi (1980); Rastogi et al. (1979); Satapathy & Sahoo (1970); Sinn & Harris (1969); Yamada et al. (1968).

S2. Experimental

A solution of hydrazine hydrate (0.001 M) was added to a solution 2-formyl thymol (0.002 M) in ethanol (50 ml) and mixture was heated on a water bath for 8 hr. Yellow crystals deposited at room temperature which were filtered and recrystallized from ethanol, (yield 83%). Yellow crystals suitable for x- ray diffraction were obtained.

Elemental analysis - Found (cal) C - 75.15 (74.96), H - 8.76 (8.33), N - 7.64 (7.97). IR (KBr, cm ^-1) 3420 (–OH), 1600 (–C=N–). NMR- (CDCl₃, dppm)- 1.22 (d, 12H, gem CH₃), 2.37 (S, 6H, Ar- CH₃) 3.33 {(heptane, 2H, CH)}, 6.68–7.110 (d, 4H, Ar—H), 9.1 (S, 2H, CH=N).

S3. Refinement

The H atoms were idealized with an O—H distance of 0.82 and C—H distances of 0.93 (aromatic C—H), 0.96 (CH₃), and 0.98 (CH) Å and U_iso(H) = 1.2U_eq(C) (1.5U_eq(C) for the CH₃ protons).

Computing details

Data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS; data reduction: XSCANS; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 2000); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The title compound with numbering scheme used. Hydrogen bonding interactions shown as dotted lines. Ellipsoids are drawn at the 20% probabilty level.
	Fig. 2. The packing arrangement viewed down the a axis showing the intramolecular N—H···O hydrogen bonding interactions (dashed bonds).

6,6-Diisopropyl-3,3'-dimethyl-2,2'-azinodiphenol

Crystal data

C22H28N2O2	F(000) = 380
Mr = 352.46	Dx = 1.158 Mg m^−3
Monoclinic, P21/n	Cu Kα radiation, λ = 1.54178 Å
Hall symbol: -P 2yn	Cell parameters from 65 reflections
a = 11.925 (2) Å	θ = 3.2–28.0°
b = 6.0622 (12) Å	µ = 0.58 mm^−1
c = 14.152 (2) Å	T = 293 K
β = 98.763 (10)°	Plate, yellow
V = 1011.2 (3) Å^3	0.60 × 0.55 × 0.10 mm
Z = 2

Data collection

Bruker P4 diffractometer	1507 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.036
Graphite monochromator	θmax = 69.0°, θmin = 7.5°
ω scans	h = −14→0
Absorption correction: empirical (using intensity measurements) via ψ scans (North et al., 1968)	k = 0→7
Tmin = 0.330, Tmax = 0.758	l = −16→17
1958 measured reflections	3 standard reflections every 97 reflections
1869 independent reflections	intensity decay: none

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)] = 0.059	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.181	H-atom parameters constrained
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0834P)^2 + 0.14P] where P = (Fo^2 + 2Fc^2)/3
1869 reflections	(Δ/σ)max = 0.001
122 parameters	Δρmax = 0.13 e Å^−3
0 restraints	Δρmin = −0.10 e Å^−3

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
O	0.22448 (12)	0.2919 (2)	0.98676 (12)	0.0945 (5)
H1O	0.1826	0.1917	0.9987	0.142*
N	0.03674 (14)	0.0815 (3)	0.98764 (12)	0.0828 (5)
C1	0.16522 (16)	0.4342 (3)	0.92369 (13)	0.0746 (5)
C2	0.04839 (16)	0.4043 (3)	0.89208 (13)	0.0745 (5)
C21	−0.01234 (18)	0.2229 (3)	0.92723 (14)	0.0799 (6)
H21A	−0.0896	0.2079	0.9054	0.096*
C3	−0.00895 (17)	0.5556 (4)	0.82627 (13)	0.0812 (6)
C31	−0.13374 (19)	0.5317 (5)	0.78758 (18)	0.1100 (8)
H31A	−0.1566	0.6481	0.7428	0.165*
H31B	−0.1771	0.5401	0.8393	0.165*
H31C	−0.1468	0.3917	0.7561	0.165*
C4	0.05091 (19)	0.7293 (4)	0.79547 (15)	0.0882 (6)
H4A	0.0137	0.8309	0.7524	0.106*
C5	0.16609 (19)	0.7543 (3)	0.82806 (15)	0.0844 (6)
H5A	0.2042	0.8726	0.8057	0.101*
C6	0.22623 (17)	0.6100 (3)	0.89244 (13)	0.0757 (5)
C61	0.35080 (17)	0.6367 (4)	0.93133 (15)	0.0864 (6)
H61A	0.3843	0.4888	0.9364	0.104*
C62	0.3655 (2)	0.7337 (5)	1.03203 (17)	0.1066 (8)
H62A	0.3250	0.6448	1.0717	0.160*
H62B	0.3362	0.8814	1.0294	0.160*
H62C	0.4446	0.7358	1.0583	0.160*
C63	0.4165 (2)	0.7718 (5)	0.8680 (2)	0.1156 (9)
H63A	0.4026	0.7148	0.8039	0.173*
H63B	0.4961	0.7630	0.8919	0.173*
H63C	0.3924	0.9228	0.8679	0.173*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O	0.0887 (9)	0.0828 (9)	0.1125 (11)	−0.0062 (7)	0.0172 (8)	0.0219 (8)
N	0.0919 (11)	0.0713 (10)	0.0910 (11)	−0.0131 (8)	0.0326 (8)	−0.0045 (8)
C1	0.0848 (12)	0.0698 (10)	0.0714 (10)	−0.0033 (9)	0.0190 (8)	−0.0002 (8)
C2	0.0846 (12)	0.0719 (11)	0.0704 (10)	−0.0072 (9)	0.0221 (9)	−0.0069 (8)
C21	0.0863 (12)	0.0783 (12)	0.0796 (12)	−0.0087 (9)	0.0268 (9)	−0.0095 (10)
C3	0.0874 (12)	0.0900 (13)	0.0682 (10)	−0.0044 (10)	0.0183 (9)	−0.0037 (9)
C31	0.0914 (15)	0.136 (2)	0.1000 (16)	−0.0058 (14)	0.0078 (12)	0.0137 (15)
C4	0.1015 (15)	0.0890 (14)	0.0735 (12)	−0.0008 (11)	0.0113 (10)	0.0087 (10)
C5	0.1018 (15)	0.0780 (12)	0.0757 (11)	−0.0094 (10)	0.0211 (10)	0.0034 (9)
C6	0.0855 (11)	0.0711 (10)	0.0735 (10)	−0.0079 (9)	0.0214 (9)	−0.0027 (9)
C61	0.0828 (12)	0.0834 (13)	0.0963 (14)	−0.0080 (10)	0.0241 (10)	0.0047 (11)
C62	0.0906 (14)	0.131 (2)	0.0956 (16)	−0.0111 (14)	0.0072 (11)	−0.0023 (14)
C63	0.1092 (17)	0.124 (2)	0.1194 (19)	−0.0348 (15)	0.0353 (14)	0.0092 (16)

Geometric parameters (Å, º)

O—C1	1.359 (2)	C4—C5	1.389 (3)
O—H1O	0.8200	C4—H4A	0.9300
N—C21	1.287 (3)	C5—C6	1.382 (3)
N—N^i	1.400 (3)	C5—H5A	0.9300
C1—C6	1.400 (3)	C6—C61	1.512 (3)
C1—C2	1.409 (3)	C61—C63	1.518 (3)
C2—C3	1.408 (3)	C61—C62	1.527 (3)
C2—C21	1.446 (3)	C61—H61A	0.9800
C21—H21A	0.9300	C62—H62A	0.9600
C3—C4	1.380 (3)	C62—H62B	0.9600
C3—C31	1.512 (3)	C62—H62C	0.9600
C31—H31A	0.9600	C63—H63A	0.9600
C31—H31B	0.9600	C63—H63B	0.9600
C31—H31C	0.9600	C63—H63C	0.9600
C1—O—H1O	109.5	C6—C5—H5A	118.7
C21—N—N^i	113.4 (2)	C4—C5—H5A	118.7
O—C1—C6	116.59 (18)	C5—C6—C1	116.59 (19)
O—C1—C2	121.14 (17)	C5—C6—C61	123.68 (18)
C6—C1—C2	122.27 (18)	C1—C6—C61	119.70 (18)
C3—C2—C1	118.94 (17)	C6—C61—C63	114.18 (19)
C3—C2—C21	120.31 (18)	C6—C61—C62	110.35 (17)
C1—C2—C21	120.75 (18)	C63—C61—C62	110.4 (2)
N—C21—C2	122.29 (19)	C6—C61—H61A	107.2
N—C21—H21A	118.9	C63—C61—H61A	107.2
C2—C21—H21A	118.9	C62—C61—H61A	107.2
C4—C3—C2	118.93 (18)	C61—C62—H62A	109.5
C4—C3—C31	119.1 (2)	C61—C62—H62B	109.5
C2—C3—C31	121.95 (19)	H62A—C62—H62B	109.5
C3—C31—H31A	109.5	C61—C62—H62C	109.5
C3—C31—H31B	109.5	H62A—C62—H62C	109.5
H31A—C31—H31B	109.5	H62B—C62—H62C	109.5
C3—C31—H31C	109.5	C61—C63—H63A	109.5
H31A—C31—H31C	109.5	C61—C63—H63B	109.5
H31B—C31—H31C	109.5	H63A—C63—H63B	109.5
C3—C4—C5	120.7 (2)	C61—C63—H63C	109.5
C3—C4—H4A	119.6	H63A—C63—H63C	109.5
C5—C4—H4A	119.6	H63B—C63—H63C	109.5
C6—C5—C4	122.52 (19)
O—C1—C2—C3	−179.61 (17)	C31—C3—C4—C5	−178.8 (2)
C6—C1—C2—C3	0.5 (3)	C3—C4—C5—C6	−0.4 (3)
O—C1—C2—C21	1.0 (3)	C4—C5—C6—C1	0.2 (3)
C6—C1—C2—C21	−178.88 (17)	C4—C5—C6—C61	−178.17 (19)
N^i—N—C21—C2	−179.80 (17)	O—C1—C6—C5	179.78 (16)
C3—C2—C21—N	−179.75 (17)	C2—C1—C6—C5	−0.3 (3)
C1—C2—C21—N	−0.4 (3)	O—C1—C6—C61	−1.7 (3)
C1—C2—C3—C4	−0.6 (3)	C2—C1—C6—C61	178.18 (17)
C21—C2—C3—C4	178.78 (17)	C5—C6—C61—C63	−23.7 (3)
C1—C2—C3—C31	178.73 (18)	C1—C6—C61—C63	158.0 (2)
C21—C2—C3—C31	−1.9 (3)	C5—C6—C61—C62	101.3 (2)
C2—C3—C4—C5	0.5 (3)	C1—C6—C61—C62	−77.0 (2)

Symmetry code: (i) −x, −y, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O—H1O···N	0.82	1.85	2.578 (2)	148