Hydrogen-bridged chelate ring-assisted π-stacking interactions

A salicylideneaniline (SA) derivative, (6Z)-6-({[2-(hydroxymethyl)phenyl]amino}methylidene)-3,5-dimethoxycyclohexa-2,4-dien-1-one monohydrate, has an increased aromaticity within its hydrogen-bridged chelate ring owing to its NH character. In the reported crystal structure, nonconventional π-stacking interactions, which are referred to as hybrid π-stacking interactions, are observed between a quasiaromatic chelate ring, formed as a result of the resonance-assisted intramolecular hydrogen bond and ordinary aromatic rings. Besides, π-stacking interactions are also seen between two hydrogen-bridged quasiaromatic chelate rings, which are referred to as pure π-stacking interactions. A CSD search has revealed that both kinds of interactions are frequently observed in molecular crystals of SA derivatives in fully or partially NH tautomeric form, and aromaticity levels of certain fragments of SA derivatives have dramatic effects on their stacking arrangements. These interactions are distinguished from the usual π...π interactions by their formation character, i.e. both σ- and π-deficient and σ-deficient character of pure interactions is more pronounced than that of the hybrid ones.

Computing details

Data collection: STOE X-AREA (Stoe & Cie, 2002); cell refinement: STOE X-AREA (Stoe & Cie, 2002); data reduction: STOE X-RED (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2003), ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999), enCIFer (Allen et al., 2004b) and publCIF (Westrip, 2010).

(6Z)-6-({[2-(hydroxymethyl)phenyl]amino}methylidene) -3,5-dimethoxycyclohexa-2,4-dien-1-one monohydrate

Crystal data

C16H17NO4·H2O	Z = 2
Mr = 305.32	F(000) = 324
Triclinic, P1	Dx = 1.336 Mg m^−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.0816 (6) Å	Cell parameters from 17629 reflections
b = 11.0087 (12) Å	θ = 1.5–27.7°
c = 14.5301 (16) Å	µ = 0.10 mm^−1
α = 108.935 (8)°	T = 296 K
β = 97.042 (9)°	Plate, yellow
γ = 93.092 (9)°	0.65 × 0.31 × 0.06 mm
V = 759.24 (15) Å^3

Data collection

STOE IPDS 2 diffractometer	1913 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.050
Graphite monochromator	θmax = 26.0°, θmin = 1.5°
Detector resolution: 6.67 pixels mm^-1	h = −6→6
ω–scan	k = −13→13
12593 measured reflections	l = −17→17
2989 independent 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)] = 0.057	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.158	All H-atom parameters refined
S = 0.97	w = 1/[σ^2(Fo^2) + (0.0898P)^2 + 0.0419P] where P = (Fo^2 + 2Fc^2)/3
2989 reflections	(Δ/σ)max = 0.002
275 parameters	Δρmax = 0.16 e Å^−3
3 restraints	Δρmin = −0.16 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
O5W	0.7597 (6)	0.0611 (3)	0.5138 (2)	0.0825 (8)
N1	0.5087 (4)	0.2983 (2)	0.25145 (15)	0.0477 (6)
O3	−0.3605 (4)	0.68493 (18)	0.21785 (13)	0.0654 (6)
O1	0.3468 (4)	0.50820 (17)	0.36107 (12)	0.0559 (5)
C4	−0.2042 (6)	0.4969 (3)	0.12552 (19)	0.0551 (7)
C13	0.6909 (5)	0.2041 (2)	0.24413 (17)	0.0456 (6)
C6	0.1580 (5)	0.4032 (2)	0.19478 (17)	0.0448 (6)
C2	0.0000 (5)	0.6035 (3)	0.29541 (19)	0.0497 (7)
C7	0.3269 (5)	0.3061 (2)	0.18177 (18)	0.0472 (6)
C11	1.0602 (6)	0.1277 (3)	0.3198 (2)	0.0578 (7)
C12	0.8772 (5)	0.2188 (2)	0.32696 (17)	0.0441 (6)
C3	−0.1827 (5)	0.5967 (2)	0.21705 (18)	0.0476 (6)
C1	0.1770 (5)	0.5060 (2)	0.28775 (17)	0.0443 (6)
C5	−0.0388 (6)	0.4024 (2)	0.11492 (17)	0.0503 (7)
O2	0.6682 (4)	0.29633 (17)	0.46902 (13)	0.0533 (5)
O5	−0.0430 (5)	0.30067 (19)	0.03069 (13)	0.0731 (7)
C8	0.6900 (6)	0.1021 (3)	0.1585 (2)	0.0617 (8)
C14	0.8808 (6)	0.3265 (3)	0.42238 (18)	0.0480 (6)
C10	1.0597 (7)	0.0257 (3)	0.2346 (2)	0.0685 (9)
C31	−0.3635 (9)	0.7875 (3)	0.3087 (2)	0.0700 (10)
C9	0.8739 (7)	0.0132 (3)	0.1534 (2)	0.0679 (9)
C51	−0.2462 (9)	0.2908 (4)	−0.0502 (2)	0.0818 (12)
H1	0.506 (5)	0.357 (3)	0.305 (2)	0.045 (7)*
H7	0.309 (5)	0.239 (3)	0.119 (2)	0.052 (7)*
H21	0.670 (7)	0.364 (3)	0.523 (2)	0.075 (10)*
H6W	0.730 (8)	0.126 (3)	0.501 (3)	0.092 (13)*
H5W	0.678 (9)	−0.003 (4)	0.475 (5)	0.29 (5)*
H8	0.571 (6)	0.093 (2)	0.105 (2)	0.049 (7)*
H11	1.187 (6)	0.134 (3)	0.374 (2)	0.063 (8)*
H9	0.875 (6)	−0.054 (3)	0.094 (2)	0.074 (9)*
H10	1.180 (7)	−0.038 (3)	0.229 (2)	0.076 (9)*
H14A	0.859 (5)	0.409 (3)	0.4104 (19)	0.055 (8)*
H14B	1.071 (7)	0.333 (3)	0.462 (2)	0.072 (9)*
H2	0.015 (5)	0.669 (3)	0.355 (2)	0.052 (7)*
H4	−0.336 (6)	0.495 (2)	0.079 (2)	0.049 (7)*
H51A	−0.219 (8)	0.218 (4)	−0.098 (3)	0.108 (13)*
H51B	−0.228 (8)	0.367 (4)	−0.077 (3)	0.095 (12)*
H51C	−0.431 (9)	0.291 (4)	−0.027 (3)	0.099 (13)*
H31A	−0.503 (8)	0.831 (3)	0.296 (2)	0.083 (10)*
H31B	−0.192 (8)	0.841 (3)	0.326 (3)	0.080 (11)*
H31C	−0.389 (7)	0.744 (3)	0.364 (3)	0.084 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
O5W	0.0846 (18)	0.0619 (14)	0.1055 (19)	0.0129 (13)	0.0215 (15)	0.0306 (14)
N1	0.0540 (14)	0.0431 (11)	0.0383 (11)	0.0152 (10)	0.0010 (10)	0.0036 (9)
O3	0.0707 (14)	0.0643 (12)	0.0524 (11)	0.0339 (10)	−0.0055 (10)	0.0084 (9)
O1	0.0584 (12)	0.0574 (11)	0.0411 (9)	0.0218 (9)	−0.0072 (8)	0.0045 (8)
C4	0.0581 (18)	0.0613 (16)	0.0409 (13)	0.0183 (14)	−0.0074 (13)	0.0136 (12)
C13	0.0454 (15)	0.0433 (13)	0.0452 (13)	0.0127 (11)	0.0046 (11)	0.0103 (10)
C6	0.0479 (15)	0.0456 (13)	0.0398 (12)	0.0076 (11)	0.0051 (11)	0.0128 (10)
C2	0.0516 (16)	0.0510 (14)	0.0397 (13)	0.0141 (12)	0.0029 (12)	0.0060 (11)
C7	0.0524 (16)	0.0469 (13)	0.0363 (12)	0.0093 (11)	0.0014 (11)	0.0069 (11)
C11	0.0520 (18)	0.0611 (17)	0.0578 (16)	0.0142 (13)	−0.0027 (14)	0.0190 (13)
C12	0.0413 (14)	0.0424 (13)	0.0452 (13)	0.0034 (10)	0.0032 (11)	0.0111 (10)
C3	0.0473 (15)	0.0516 (14)	0.0442 (13)	0.0156 (12)	0.0053 (11)	0.0154 (11)
C1	0.0439 (15)	0.0481 (13)	0.0393 (12)	0.0107 (11)	0.0029 (11)	0.0127 (10)
C5	0.0589 (17)	0.0509 (14)	0.0363 (12)	0.0157 (13)	0.0013 (11)	0.0085 (11)
O2	0.0596 (12)	0.0486 (10)	0.0428 (10)	0.0057 (9)	0.0070 (9)	0.0034 (8)
O5	0.0960 (17)	0.0657 (12)	0.0392 (9)	0.0383 (11)	−0.0139 (10)	−0.0037 (8)
C8	0.0629 (19)	0.0619 (17)	0.0464 (15)	0.0213 (14)	−0.0064 (14)	0.0019 (12)
C14	0.0485 (17)	0.0454 (14)	0.0438 (13)	0.0031 (11)	−0.0001 (12)	0.0092 (11)
C10	0.069 (2)	0.0590 (17)	0.0700 (19)	0.0322 (16)	0.0052 (15)	0.0096 (14)
C31	0.074 (2)	0.0616 (19)	0.0626 (19)	0.0341 (19)	−0.0019 (17)	0.0049 (15)
C9	0.073 (2)	0.0592 (17)	0.0570 (17)	0.0269 (15)	0.0037 (15)	−0.0010 (14)
C51	0.098 (3)	0.082 (2)	0.0435 (16)	0.035 (2)	−0.0184 (17)	−0.0020 (16)

Geometric parameters (Å, º)

O5W—H6W	0.81 (3)	C11—C12	1.393 (4)
O5W—H5W	0.80 (3)	C11—H11	0.93 (3)
N1—C7	1.312 (3)	C12—C14	1.501 (3)
N1—C13	1.414 (3)	C5—O5	1.361 (3)
N1—H1	0.84 (3)	O2—C14	1.423 (3)
O3—C3	1.360 (3)	O2—H21	0.89 (3)
O3—C31	1.434 (3)	O5—C51	1.437 (4)
O1—C1	1.279 (3)	C8—C9	1.380 (4)
C4—C5	1.355 (4)	C8—H8	0.90 (3)
C4—C3	1.411 (4)	C14—H14A	0.99 (3)
C4—H4	0.89 (3)	C14—H14B	1.05 (3)
C13—C8	1.379 (3)	C10—C9	1.382 (4)
C13—C12	1.396 (3)	C10—H10	0.95 (3)
C6—C7	1.386 (3)	C31—H31A	0.91 (4)
C6—C5	1.433 (3)	C31—H31B	0.98 (4)
C6—C1	1.442 (3)	C31—H31C	1.08 (4)
C2—C3	1.357 (3)	C9—H9	0.94 (3)
C2—C1	1.422 (3)	C51—H51A	0.90 (4)
C2—H2	0.93 (3)	C51—H51B	1.05 (4)
C7—H7	0.96 (3)	C51—H51C	1.03 (4)
C11—C10	1.374 (4)
H6W—O5W—H5W	113 (6)	C4—C5—O5	124.4 (2)
C7—N1—C13	127.4 (2)	C4—C5—C6	121.0 (2)
C7—N1—H1	112.2 (17)	O5—C5—C6	114.6 (2)
C13—N1—H1	120.4 (17)	C14—O2—H21	106 (2)
C3—O3—C31	117.7 (2)	C5—O5—C51	117.1 (2)
C5—C4—C3	119.2 (2)	C13—C8—C9	120.5 (3)
C5—C4—H4	122.3 (16)	C13—C8—H8	120.1 (16)
C3—C4—H4	118.3 (16)	C9—C8—H8	119.4 (16)
C8—C13—C12	120.5 (2)	O2—C14—C12	108.2 (2)
C8—C13—N1	122.0 (2)	O2—C14—H14A	110.1 (16)
C12—C13—N1	117.5 (2)	C12—C14—H14A	110.5 (15)
C7—C6—C5	119.9 (2)	O2—C14—H14B	114.4 (17)
C7—C6—C1	121.1 (2)	C12—C14—H14B	105.4 (17)
C5—C6—C1	119.0 (2)	H14A—C14—H14B	108 (2)
C3—C2—C1	120.0 (2)	C11—C10—C9	119.4 (3)
C3—C2—H2	122.7 (16)	C11—C10—H10	123.2 (19)
C1—C2—H2	117.3 (16)	C9—C10—H10	117.4 (19)
N1—C7—C6	123.8 (2)	O3—C31—H31A	104 (2)
N1—C7—H7	117.4 (16)	O3—C31—H31B	109 (2)
C6—C7—H7	118.8 (16)	H31A—C31—H31B	113 (3)
C10—C11—C12	121.9 (3)	O3—C31—H31C	107.7 (18)
C10—C11—H11	118.1 (18)	H31A—C31—H31C	113 (3)
C12—C11—H11	120.1 (18)	H31B—C31—H31C	110 (3)
C11—C12—C13	117.8 (2)	C8—C9—C10	120.0 (3)
C11—C12—C14	119.9 (2)	C8—C9—H9	119.5 (19)
C13—C12—C14	122.2 (2)	C10—C9—H9	120.4 (19)
O3—C3—C2	124.0 (2)	O5—C51—H51A	104 (3)
O3—C3—C4	113.2 (2)	O5—C51—H51B	113 (2)
C2—C3—C4	122.8 (2)	H51A—C51—H51B	108 (3)
O1—C1—C2	121.4 (2)	O5—C51—H51C	109 (2)
O1—C1—C6	120.6 (2)	H51A—C51—H51C	115 (3)
C2—C1—C6	118.0 (2)	H51B—C51—H51C	107 (3)
C7—N1—C13—C8	−2.3 (5)	C7—C6—C1—O1	−1.6 (4)
C7—N1—C13—C12	176.7 (3)	C5—C6—C1—O1	178.6 (3)
C13—N1—C7—C6	−179.0 (3)	C7—C6—C1—C2	179.1 (3)
C5—C6—C7—N1	−178.6 (3)	C5—C6—C1—C2	−0.8 (4)
C1—C6—C7—N1	1.5 (4)	C3—C4—C5—O5	179.3 (3)
C10—C11—C12—C13	−0.2 (5)	C3—C4—C5—C6	−0.6 (5)
C10—C11—C12—C14	178.3 (3)	C7—C6—C5—C4	−179.3 (3)
C8—C13—C12—C11	0.1 (4)	C1—C6—C5—C4	0.5 (4)
N1—C13—C12—C11	−178.9 (2)	C7—C6—C5—O5	0.9 (4)
C8—C13—C12—C14	−178.4 (3)	C1—C6—C5—O5	−179.3 (2)
N1—C13—C12—C14	2.6 (4)	C4—C5—O5—C51	−3.3 (5)
C31—O3—C3—C2	−3.3 (4)	C6—C5—O5—C51	176.6 (3)
C31—O3—C3—C4	177.3 (3)	C12—C13—C8—C9	−0.2 (5)
C1—C2—C3—O3	179.6 (3)	N1—C13—C8—C9	178.8 (3)
C1—C2—C3—C4	−1.1 (5)	C11—C12—C14—O2	−102.7 (3)
C5—C4—C3—O3	−179.8 (3)	C13—C12—C14—O2	75.8 (3)
C5—C4—C3—C2	0.9 (5)	C12—C11—C10—C9	0.4 (5)
C3—C2—C1—O1	−178.3 (3)	C13—C8—C9—C10	0.3 (6)
C3—C2—C1—C6	1.1 (4)	C11—C10—C9—C8	−0.4 (6)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···O1	0.84 (3)	1.88 (3)	2.587 (3)	142 (2)
O5W—H6W···O2	0.81 (3)	2.10 (3)	2.915 (3)	178 (4)
O2—H21···O1^i	0.89 (3)	1.82 (4)	2.710 (2)	174 (3)
O5W—H5W···O5W^ii	0.80 (3)	2.32 (3)	2.819 (6)	121 (3)
C51—H51B···O3^iii	1.05 (4)	2.63 (4)	3.048 (4)	103 (2)

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