4-[Bis(1,5-dimethyl-1H-pyrazol-3-yl­meth­yl)­amino]phenol monohydrate

The crystal structure of the title compound, C₁₈H₂₃N₅O·H₂O, shows mol­ecules containing a phenol group linked perpendicularly to a roughly planar fragment comprising two pyrazole rings. Mol­ecules are stacked perpendicular to the [101] direction, with their phenol groups disposed alternately. The mol­ecular packing in the crystal is stabilized by hydrogen bonding involving water mol­ecules.

S1. Comment

There is a considerable interest in the synthesis of multidentate organic ligands for a variety of purposes. These ligands are involved in the building of organic complexes that are used as potential bioinorganic model systems, as well as in the immobilization on the surface of a solid material such as an organic resin or a silica gel. Copper phenolate coordination occurs in a number of native and metal-substituted proteins (Klinman, 1996). A biologically important example of phenoxy coordination to Cu^II concerns the metalloproteases astacin and serralysin, where Cu^II substitution for the native Zn gives a hyper-reactive enzyme (Park & Ming, 1998, 2002; Locher et al., 1987).

In this paper, we report the synthesis and the crystal structure of the monohydrate of a new pyrazolyl ligand 4-[bis(1,5-dimethyl-1H-pyrazol-3-ylmethyl)amino]phenol. The title compound, (I), was prepared using a method developed in our laboratory (Radi et al., 2000, 2004; Malek et al., 2002, 2004) by condensation of 3-chloromethyl-1,5-dimethylpyrazole with p-aminophenol in a 2:1 ratio in acetonitrile using sodium carbonate as base.

The product was characterized by IR and NMR spectroscopy and by mass spectrometry. Molecules of the organic ligand have been found to crystallize in the ratio 1:1 with water molecules.

The molecule may be viewed as resulting from substitution of the two amine H atoms of an aminophenol system by pyrazolyl methyl groups that are bonded to the phenyl ring by C—C—N (Fig. 1) instead of the N—C—N junctions that are found in bis(3,5-dimethylpyrazol-1-yl)methyl]aniline (pabd) (Driessen, 1982; Blonk et al., 1985). The dihedral angles of 81.5 (2) and 80.4 (2)° between the planes of the pyrazole rings and the plane of the phenyl ring are slightly different from those observed (84.7 and 79.8°) in N,N,N',N'-tetrakis[(1,5-dimethylpyrazol-3-yl)methyl]-1,4-phenylenediamine, (II) (Bouabdallah et al., 2005), in which the pyrazole rings are also linked to the phenyl ring by C—C—N junctions. These values strongly differ from the dihedral angles of 50.4 (2) and 72.1 (2)° found in the isomeric compound N,N,N',N'-tetrakis-[(3,5-dimethylpyrazol-1-yl)methyl]-1,4-phenylenediamine, (III), where junctions are of the N—C—N type (Daoudi et al., 2003). The value of 20.2 (4)° for the dihedral angle between the planes of the two pyrazole rings, which indicates the deviation from flatness, is to be compared with 7.7° (Bouabdallah et al., 2005) and to 87.9 (1)° (Daoudi et al., 2003) in the related compounds (II) and (III).

The C10—C11 and C16—C17 bond lengths are very close to the distance of 1.49 Å observed in 4-acetyl-3(5)-amino-5(3)-methylpyrazole (Hergold-Brundic et al., 1991). The low steric strain between the methyl groups may be explained by the torsion angle values of −1.0 (4)° for C12—N3—C10—C11 and 2.5 (4)° for C18—N6—C16—C17.

The C—N—C angles around the aniline N1 atom obviously deviate from the ideal tetrahedral value but they are very close to those found for (II) (Bouabdallah et al., 2005). The C6—N1 distance in (I) is slightly longer than the corresponding distance in (II) (Bouabdallah et al., 2005). This difference can be explained by some involvement, through electron donation, of the aniline N atom in the multicenter bonding of the phenyl ring.

The most interesting feature of this structure deals with the particular arrangement of molecules in the crystal. The almost planar part of the molecule constituted by the two roughly coplanar pyrazole rings is aligned parallel to the (101) diagonal plane. Molecules are stacked nearly along the [101] direction with their phenol groups alternately disposed. The molecular packing is stabilized by hydrogen bonding of phenol groups and pyrazole rings with water molecules.

An extended three-dimensional network is built in this way (Fig. 2). Atom O2 of the water molecule is involved in three hydrogen bonds with three neighbouring C₁₈H₂₃N₅O molecules, one to a hydroxy group (O2···O1), and two to pyrazole N atoms (O2···N4ⁱⁱ and O2···N2ⁱⁱⁱ) [symmetry codes: (ii) −x + 1, y − 1/2, −z + 1/2 and (iii) −x + 1, −y + 1, − z + 1].

S2. Experimental

A solution of p-aminophenol (1.13 g, 1.04 × 10 ⁻² mol) in acetonitrile (50 ml) was added dropwise to a mixture of 3-chloromethyl-1,5-dimethylpyrazole (2.03 g, 5 × 10 ⁻² mol) and sodium carbonate (8.8 g, 1.6 × 10 ⁻² mol) of in acetonitrile (200 ml). The mixture was refluxed for four days. The organic layer was filtered and concentrated at a reduced pressure to form (I) (yield 95%), which was recrystallized from dimethyl sulfoxide into light-yellow crystals suitable for X-ray analysis. M.p. 433–434 K (DMSO).

S3. Refinement

All C-bound H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with U_iso(H) values of 1.5U_eq(C) for methyl groups and 1.2U_eq(C) for other H atoms. The H atoms attached to O atoms were first placed at their ideal positions, and then their positions and displacement parameters were refined. Please check; the O—H distances given in CIF are not the same as those in Table 2.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis RED Oxford Diffraction, 2004); data reduction: CrysAlis RED; 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).

Figures

	Fig. 1. A view of (I); displacement ellipsoids are drawn at the 30% probability level.
	Fig. 2. The packing of (I), showing the hydrogen bonds involving the hydroxy groups and water molecules. For clarity, H atoms not involved in hydrogen bonding have been omitted.

4-[Bis(1,5-dimethyl-1H-pyrazol-3-ylmethyl)amino]phenol monohydrate

Crystal data

C18H23N5O·H2O	F(000) = 736
Mr = 343.43	Dx = 1.279 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 14369 reflections
a = 13.922 (1) Å	θ = 3.6–25.0°
b = 9.4366 (6) Å	µ = 0.09 mm^−1
c = 16.799 (1) Å	T = 173 K
β = 126.08 (1)°	Platelet, light yellow
V = 1783.7 (3) Å^3	0.34 × 0.32 × 0.22 mm
Z = 4

Data collection

Oxford Diffraction Xcalibur CCD diffractometer	2500 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.061
Graphite monochromator	θmax = 25.0°, θmin = 3.6°
ω scans	h = −16→15
14369 measured reflections	k = −11→11
3128 independent reflections	l = −17→19

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)] = 0.049	H-atom parameters constrained
wR(F^2) = 0.124	w = 1/[σ^2(Fo^2) + (0.0589P)^2 + 0.3372P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max = 0.005
3128 reflections	Δρmax = 0.19 e Å^−3
243 parameters	Δρmin = −0.20 e Å^−3
0 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0072 (13)

Special details

Experimental. Spectroscopic analysis,

¹H NMR (CDCl₃p.p.m.): 2,15 (s, 6H, CH₃); 3,67 (s, 6H, N—CH₃); 4,34 (s, 4H, CH₂); 5,89 (s, 2H, PzH); 6,56 (d, 2H, CHben); 6,70 (d, 2H, CH_ben); 7,24 (s, 1H, OH). 13 C RMN (CDCl₃ p.p.m.):11,62 (PzCH₃); 36,06 (NCH₃); 50,08 (PzCH₂); 104,97 (CPzH); 115,89 (m-C); 116,28 (i-C); 116,59 (o-C); 116,98 (p-C); 139,65 (CPzCH₃); 149,59 (CPzCH₂). IR (KBr,cm-1):3300(OH); 3100(CH_ar);3000(=CH); 2900(CH); 2780; 1500(C=C); 1430; 1370; 1300; 1250; 1230; 1170; 1020; 810; 700. M·S.: m/z: 325(M+)(11%), 216(100%), 109(43%).

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
O1	1.21937 (12)	0.59909 (16)	0.44868 (11)	0.0363 (4)
H3O	1.232 (3)	0.547 (3)	0.503 (2)	0.075 (9)*
N1	0.74396 (14)	0.58099 (17)	0.11777 (11)	0.0271 (4)
N2	0.59424 (14)	0.41870 (17)	0.21376 (12)	0.0288 (4)
N3	0.57197 (14)	0.27765 (18)	0.21324 (12)	0.0303 (4)
N4	0.78734 (14)	0.65795 (17)	−0.07225 (11)	0.0283 (4)
N6	0.83155 (14)	0.56142 (17)	−0.10334 (11)	0.0271 (4)
C1	0.89924 (17)	0.5196 (2)	0.28913 (13)	0.0258 (4)
H1	0.8433	0.4695	0.2914	0.031*
C2	1.01619 (17)	0.5222 (2)	0.37171 (14)	0.0276 (5)
H2	1.0379	0.4741	0.4284	0.033*
C3	1.10112 (17)	0.5963 (2)	0.37031 (14)	0.0265 (5)
C4	1.06567 (17)	0.6718 (2)	0.28687 (14)	0.0294 (5)
H4	1.1211	0.7254	0.2861	0.035*
C5	0.94874 (17)	0.6688 (2)	0.20427 (14)	0.0279 (5)
H5	0.9270	0.7204	0.1488	0.033*
C6	0.86314 (16)	0.58998 (19)	0.20279 (13)	0.0234 (4)
C7	0.65204 (17)	0.5769 (2)	0.13425 (15)	0.0288 (5)
H7A	0.5795	0.6167	0.0771	0.035*
H7B	0.6767	0.6366	0.1903	0.035*
C8	0.62551 (16)	0.4312 (2)	0.15281 (13)	0.0258 (5)
C9	0.62393 (16)	0.3000 (2)	0.11384 (14)	0.0301 (5)
H9	0.6424	0.2815	0.0699	0.036*
C10	0.58928 (16)	0.2036 (2)	0.15391 (15)	0.0316 (5)
C11	0.5693 (2)	0.0474 (2)	0.13903 (19)	0.0477 (6)
H11A	0.4857	0.0280	0.1009	0.072*
H11B	0.6090	0.0013	0.2019	0.072*
H11C	0.6004	0.0125	0.1047	0.072*
C12	0.5350 (2)	0.2287 (3)	0.27301 (16)	0.0415 (6)
H12A	0.5364	0.1270	0.2748	0.062*
H12B	0.4559	0.2615	0.2451	0.062*
H12C	0.5883	0.2650	0.3387	0.062*
C13	0.71221 (18)	0.6542 (2)	0.02903 (14)	0.0292 (5)
H13A	0.7393	0.7517	0.0452	0.035*
H13B	0.6264	0.6553	−0.0184	0.035*
C14	0.76612 (16)	0.5845 (2)	−0.01640 (13)	0.0257 (4)
C15	0.79692 (17)	0.4424 (2)	−0.01141 (14)	0.0288 (5)
H15	0.7908	0.3703	0.0231	0.035*
C16	0.83806 (17)	0.4308 (2)	−0.06789 (14)	0.0282 (5)
C17	0.8824 (2)	0.3053 (2)	−0.09077 (16)	0.0372 (5)
H17A	0.9639	0.3202	−0.0656	0.056*
H17B	0.8354	0.2922	−0.1608	0.056*
H17C	0.8765	0.2226	−0.0606	0.056*
C18	0.8688 (2)	0.6071 (2)	−0.16389 (16)	0.0367 (5)
H18A	0.8029	0.6010	−0.2322	0.055*
H18B	0.9320	0.5472	−0.1515	0.055*
H18C	0.8963	0.7033	−0.1480	0.055*
O2	0.26343 (17)	0.4500 (2)	0.59831 (13)	0.0498 (5)
H1O	0.248 (2)	0.358 (4)	0.5957 (19)	0.063 (8)*
H2O	0.309 (3)	0.478 (4)	0.655 (3)	0.086 (11)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O1	0.0272 (8)	0.0446 (9)	0.0279 (8)	−0.0067 (7)	0.0111 (7)	0.0028 (7)
N1	0.0237 (9)	0.0343 (9)	0.0243 (8)	0.0035 (7)	0.0148 (7)	0.0055 (7)
N2	0.0271 (9)	0.0303 (9)	0.0284 (9)	−0.0036 (7)	0.0160 (8)	−0.0001 (7)
N3	0.0277 (9)	0.0300 (9)	0.0299 (9)	−0.0041 (7)	0.0152 (8)	0.0006 (8)
N4	0.0309 (9)	0.0277 (9)	0.0281 (9)	0.0033 (7)	0.0183 (8)	0.0028 (7)
N6	0.0301 (9)	0.0277 (9)	0.0258 (9)	0.0000 (7)	0.0178 (8)	0.0009 (7)
C1	0.0267 (11)	0.0248 (10)	0.0281 (10)	−0.0029 (8)	0.0174 (9)	0.0010 (8)
C2	0.0331 (11)	0.0250 (10)	0.0249 (10)	−0.0003 (9)	0.0171 (9)	0.0034 (8)
C3	0.0261 (10)	0.0265 (10)	0.0259 (10)	−0.0030 (8)	0.0148 (9)	−0.0046 (8)
C4	0.0300 (11)	0.0321 (11)	0.0302 (11)	−0.0086 (9)	0.0200 (10)	−0.0012 (9)
C5	0.0326 (11)	0.0305 (11)	0.0237 (10)	−0.0010 (9)	0.0184 (9)	0.0024 (8)
C6	0.0257 (10)	0.0235 (10)	0.0241 (10)	0.0009 (8)	0.0164 (9)	−0.0017 (8)
C7	0.0254 (11)	0.0329 (11)	0.0290 (10)	0.0035 (8)	0.0164 (9)	0.0026 (9)
C8	0.0170 (9)	0.0339 (11)	0.0211 (9)	0.0002 (8)	0.0082 (8)	0.0001 (8)
C9	0.0224 (10)	0.0374 (12)	0.0267 (10)	0.0016 (9)	0.0124 (9)	−0.0029 (9)
C10	0.0199 (10)	0.0344 (11)	0.0293 (10)	0.0021 (9)	0.0083 (9)	−0.0006 (9)
C11	0.0449 (14)	0.0341 (13)	0.0528 (15)	−0.0009 (10)	0.0224 (13)	−0.0038 (11)
C12	0.0427 (13)	0.0417 (13)	0.0429 (13)	−0.0081 (11)	0.0267 (11)	0.0031 (11)
C13	0.0277 (10)	0.0329 (11)	0.0254 (10)	0.0061 (9)	0.0147 (9)	0.0063 (9)
C14	0.0216 (10)	0.0308 (11)	0.0199 (9)	0.0009 (8)	0.0096 (8)	0.0032 (8)
C15	0.0305 (11)	0.0291 (11)	0.0270 (10)	0.0011 (9)	0.0170 (9)	0.0059 (9)
C16	0.0270 (11)	0.0295 (11)	0.0241 (10)	0.0013 (8)	0.0128 (9)	0.0008 (8)
C17	0.0458 (13)	0.0322 (11)	0.0370 (12)	0.0034 (10)	0.0263 (11)	0.0009 (10)
C18	0.0435 (13)	0.0390 (12)	0.0375 (12)	−0.0006 (10)	0.0293 (11)	0.0039 (10)
O2	0.0705 (13)	0.0329 (10)	0.0257 (9)	−0.0118 (9)	0.0170 (9)	−0.0015 (8)

Geometric parameters (Å, º)

O1—C3	1.375 (2)	C7—H7B	0.9700
O1—O2^i	2.619 (2)	C8—C9	1.394 (3)
O1—H3O	0.96 (3)	C9—C10	1.377 (3)
N1—C6	1.417 (2)	C9—H9	0.9300
N1—C13	1.456 (2)	C10—C11	1.494 (3)
N1—C7	1.461 (2)	C11—H11A	0.9600
N2—C8	1.333 (2)	C11—H11B	0.9600
N2—N3	1.366 (2)	C11—H11C	0.9600
N3—C10	1.350 (3)	C12—H12A	0.9600
N3—C12	1.447 (3)	C12—H12B	0.9600
N4—C14	1.332 (2)	C12—H12C	0.9600
N4—N6	1.364 (2)	C13—C14	1.501 (3)
N6—C16	1.349 (2)	C13—H13A	0.9700
N6—C18	1.453 (2)	C13—H13B	0.9700
C1—C2	1.384 (3)	C14—C15	1.396 (3)
C1—C6	1.392 (3)	C15—C16	1.371 (3)
C1—H1	0.9300	C15—H15	0.9300
C2—C3	1.386 (3)	C16—C17	1.486 (3)
C2—H2	0.9300	C17—H17A	0.9600
C3—C4	1.379 (3)	C17—H17B	0.9600
C4—C5	1.384 (3)	C17—H17C	0.9600
C4—H4	0.9300	C18—H18A	0.9600
C5—C6	1.393 (3)	C18—H18B	0.9600
C5—H5	0.9300	C18—H18C	0.9600
C7—C8	1.503 (3)	O2—H1O	0.89 (3)
C7—H7A	0.9700	O2—H2O	0.82 (3)
C3—O1—H3O	110.0 (17)	N3—C10—C9	106.57 (19)
C6—N1—C13	118.21 (15)	N3—C10—C11	122.5 (2)
C6—N1—C7	116.55 (15)	C9—C10—C11	130.9 (2)
C13—N1—C7	115.80 (15)	C10—C11—H11A	109.5
C8—N2—N3	104.88 (16)	C10—C11—H11B	109.5
C10—N3—N2	111.75 (17)	H11A—C11—H11B	109.5
C10—N3—C12	129.63 (19)	C10—C11—H11C	109.5
N2—N3—C12	118.62 (18)	H11A—C11—H11C	109.5
C14—N4—N6	105.04 (15)	H11B—C11—H11C	109.5
C16—N6—N4	111.69 (15)	N3—C12—H12A	109.5
C16—N6—C18	128.42 (17)	N3—C12—H12B	109.5
N4—N6—C18	119.85 (16)	H12A—C12—H12B	109.5
C2—C1—C6	121.69 (18)	N3—C12—H12C	109.5
C2—C1—H1	119.2	H12A—C12—H12C	109.5
C6—C1—H1	119.2	H12B—C12—H12C	109.5
C1—C2—C3	120.27 (18)	N1—C13—C14	111.79 (16)
C1—C2—H2	119.9	N1—C13—H13A	109.3
C3—C2—H2	119.9	C14—C13—H13A	109.3
O1—C3—C4	118.26 (17)	N1—C13—H13B	109.3
O1—C3—C2	123.08 (18)	C14—C13—H13B	109.3
C4—C3—C2	118.66 (18)	H13A—C13—H13B	107.9
C3—C4—C5	120.96 (18)	N4—C14—C15	110.77 (17)
C3—C4—H4	119.5	N4—C14—C13	120.97 (17)
C5—C4—H4	119.5	C15—C14—C13	128.22 (18)
C4—C5—C6	121.15 (18)	C16—C15—C14	105.90 (18)
C4—C5—H5	119.4	C16—C15—H15	127.1
C6—C5—H5	119.4	C14—C15—H15	127.1
C5—C6—C1	117.14 (17)	N6—C16—C15	106.60 (17)
C5—C6—N1	122.11 (17)	N6—C16—C17	122.95 (18)
C1—C6—N1	120.75 (17)	C15—C16—C17	130.46 (19)
N1—C7—C8	114.43 (16)	C16—C17—H17A	109.5
N1—C7—H7A	108.7	C16—C17—H17B	109.5
C8—C7—H7A	108.7	H17A—C17—H17B	109.5
N1—C7—H7B	108.7	C16—C17—H17C	109.5
C8—C7—H7B	108.7	H17A—C17—H17C	109.5
H7A—C7—H7B	107.6	H17B—C17—H17C	109.5
N2—C8—C9	111.13 (17)	N6—C18—H18A	109.5
N2—C8—C7	118.13 (17)	N6—C18—H18B	109.5
C9—C8—C7	130.71 (18)	H18A—C18—H18B	109.5
C10—C9—C8	105.67 (18)	N6—C18—H18C	109.5
C10—C9—H9	127.2	H18A—C18—H18C	109.5
C8—C9—H9	127.2	H18B—C18—H18C	109.5

Symmetry code: (i) x+1, y, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H1O···N4^ii	0.89 (3)	1.93 (3)	2.816 (2)	172 (3)
O2—H2O···N2^iii	0.82 (3)	2.03 (3)	2.840 (2)	169 (3)
O1—H3O···O2^i	0.96 (3)	1.66 (3)	2.619 (2)	174 (3)

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