Dichloro{2-[N-(2-hydro­xy­ethyl­ammonio­ethyl)­imino­methyl]­phenolate}zinc(II)

In the title compound, [ZnCl₂(C₁₁H₁₆N₂O₂)], the Zn atom is four-coordinated by one N atom and one O atom from the bidentate 2-[N-(2-hydroxy­ethyl­ammonio­ethyl)­imino­methyl]­phenolate ligand and two Cl atoms in a distorted tetrahedral geometry. In the crystal, the mol­ecules are stabilized by two N—H...O hydrogen bonds, to form columns along the a direction, which are further interconnected by O—H...Cl interactions into a three-dimensional network.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.022
• wR factor = 0.058
• Data-to-parameter ratio = 16.7

checkCIF results

No syntax errors found

ADDSYM reports no extra symmetry

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S1. Comment

Carbonic anhydrase is a ubiquitos zinc enzyme which catalyzes the reversible hydration of CO₂ with rates up to 10⁷ times greater than that in the uncatalyzed case (Silverman & Lindskog, 1988; Liang & Lipscomb, 1988; Christianson, 1991). In the active site, there is a zinc cation in a tetrahedral coordination geometry surrounded by three imidazole ligands (His95, His96 and His119) and a water molecule (Eriksson et al., 1988; Hakansson et al., 1992). An important contribution to the detailed understanding of the catalytic acidity of the enzyme can be made via experimental investigations on suitable model systems. A vast number of various kinds of model complexes with a structural resemblance to the native enzyme have been synthesized and characterized with regard to their acidity toward carbonic anhydrase. Today, more and more model complexes of carbonic anhydrase emerge in the literature (Makowska-Grzyska et al., 2002; Bergquist et al., 2002; Berreau et al., 2001; Bräuer et al., 2002; Chang et al., 2002; Oste et al., 2002; Sénèque et al., 2001; Topol et al., 2001; Xia et al., 2001). In the title structure, (I), the Cl atom, which is coordinated to the Zn atom tetrahedrally, can easily be detached, resulting in a model of carbonic anhydrase.

In the title compound, (I), the Zn^II atom is four-coordinated by two Cl atoms, and by one N atom and one O atom from the bidentate 2-[N-(2-hydroxyethylammonioethyl)iminomethyl]phenolate ligand. This ZnONCl₂ coordination forms a distorted tetrahedral geometry, as usually observed in the structures of zinc complexes (McCleverty et al., 1980), with angles subtended at the Zn atom of 96.1 (1)–113.5 (1)°.

The bond lengths in (I) (Table 1) are within normal ranges (Allen et al., 1987). The ligand is a zwitterion with the negative and positive charge located at atoms O1 and N2, respectively. This is supported by the geometry of the ligand and unambiguous location of the H atoms attached to the N2 atom. Atoms Zn1/O1/C1/C6/C7/N1 form a six-membered ring plane, with a maximum deviation of 0.047 (1) Å at atom O1. This plane is coplanar to the benzene ring, with a dihedral angle of 2.0 (1)°. Atoms C8, C9, C10, C11 and N2 of the 2-hydroxydiethylammonii substituent are coplanar and nearly orthogonal to the Zn1/O1/C1/C6/C7/N1 plane; the dihedral angle between these two planes is 87.9 (1)°.

In the crystal, the amino groups also act as donor to form N2—H1N2···O2ⁱⁱ and N2—H2N2···O1ⁱⁱⁱ hydrogen bonds (Table 2). These hydrogen bonds interconnect the molecules into columns along the a direction (Fig. 2). The molecular columns are further interconnected by into a three-dimensioanl network by O2—H2O···Cl1ⁱ interactions.

S2. Experimental

Equimolar salaldehyde (1 mmol, 122 mg) and 2-hydroxyaminotheylamine (1 mmol, 104 mg) were dissolved in anhydrous alcohol solution (5 ml) with stirring. To this solution, 244 mg (1 mmol) of ZnCl₂·6H₂O in anhydrous alcohol solution (5 ml) was added. The resulting solution was kept in air to evaporate slowly. After about half of the solvent had evaporated, colorless crystals of the title compound were deposited and were collected by filtration (yield 45%). Analysis calculated for C₁₁H₁₆Cl₂N₂O₂Zn: C 38.35, H 4.68, N 8.13, Cl 20.58%; found: C 38.50, H 4.72, N 8.03, Cl 20.89%. A single-crystal with a suitable size was used for X-ray diffraction study.

S3. Refinement

The H atoms attached to the parent C and O atoms were fixed geometrically (C—H = 0.93–0.97 Å and O—H = 0.90 Å) and were treated as riding atoms, whereas the H atoms attached to N2 were located from difference maps and were refined isotropically. Owing to a large fraction of weak data at higher angles, the 2θ maximum was limited to 54°.

Computing details

Data collection: SMART (Siemens, 1996); cell refinement: SAINT (Siemens, 1996); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 1997); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL, PARST (Nardelli, 1995) and PLATON (Spek, 1990).

Figures

	Fig. 1. The structure of the title compound, showing 50% probability displacement ellipsoids and the atom-numbering scheme.
	Fig. 2. The packing structure of the title compound, viewed down the b axis, showing the molecular columns running along the a direction. H atoms attached to C atoms have been omitted for clarity. The dashed lines denote intermolecular N—H···O hydrogen bonds.

[2-[(2-hydroxydiethylammonium)aminomethylene]phenolate]zinc(II)dichloride

Crystal data

[ZnCl2(C11H16N2O2)]	Z = 2
Mr = 344.53	F(000) = 352
Triclinic, P1	Dx = 1.668 Mg m^−3
a = 7.3217 (4) Å	Mo Kα radiation, λ = 0.71073 Å
b = 8.6557 (4) Å	Cell parameters from 3563 reflections
c = 11.4876 (6) Å	θ = 2.5–28.3°
α = 91.129 (1)°	µ = 2.17 mm^−1
β = 95.179 (1)°	T = 293 K
γ = 108.674 (1)°	Slab, light yellow
V = 685.97 (6) Å^3	0.50 × 0.34 × 0.20 mm

Data collection

Siemens SMART CCD area-detector diffractometer	2865 independent reflections
Radiation source: fine-focus sealed tube	2686 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.013
Detector resolution: 8.33 pixels mm^-1	θmax = 27.0°, θmin = 2.5°
ω scans	h = −9→9
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996)	k = −10→11
Tmin = 0.410, Tmax = 0.670	l = −9→14
3955 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)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.058	H atoms treated by a mixture of independent and constrained refinement
S = 1.06	w = 1/[σ^2(Fo^2) + (0.0252P)^2 + 0.2516P] where P = (Fo^2 + 2Fc^2)/3
2865 reflections	(Δ/σ)max = 0.001
172 parameters	Δρmax = 0.28 e Å^−3
0 restraints	Δρmin = −0.38 e Å^−3

Special details

Experimental. The data collection covered over a hemisphere of reciprocal space by a combination of three sets of exposures; each set had a different ϕ angle (0, 88 and 180°) for the crystal and each exposure of 10 s covered 0.3° in ω. The crystal-to-detector distance was 5 cm and the detector swing angle was −35°. Crystal decay was monitored by repeating fifty initial frames at the end of data collection and analysing the intensity of duplicate reflections, and was found to be negligible.

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
Zn1	0.30515 (3)	0.73379 (2)	0.202262 (18)	0.03490 (7)
Cl1	0.30388 (7)	0.49000 (6)	0.26253 (4)	0.04780 (12)
Cl2	0.20412 (7)	0.72523 (6)	0.01137 (4)	0.04484 (11)
O1	0.55866 (17)	0.89883 (15)	0.23841 (12)	0.0420 (3)
O2	−0.1243 (2)	0.89150 (17)	−0.11701 (13)	0.0517 (3)
H2O	−0.0963	0.8021	−0.1401	0.101 (11)*
N1	0.16307 (19)	0.83674 (17)	0.30583 (12)	0.0306 (3)
N2	−0.1863 (2)	0.78769 (17)	0.12813 (13)	0.0301 (3)
C1	0.5925 (2)	1.0344 (2)	0.30323 (14)	0.0314 (3)
C2	0.7812 (3)	1.1483 (2)	0.31512 (16)	0.0404 (4)
H2	0.8771	1.1251	0.2773	0.049*
C3	0.8278 (3)	1.2925 (2)	0.38081 (17)	0.0451 (4)
H3	0.9537	1.3651	0.3860	0.054*
C4	0.6901 (3)	1.3310 (2)	0.43929 (17)	0.0468 (4)
H4	0.7221	1.4285	0.4840	0.056*
C5	0.5054 (3)	1.2228 (2)	0.43019 (15)	0.0397 (4)
H5	0.4128	1.2481	0.4700	0.048*
C6	0.4506 (2)	1.07460 (19)	0.36280 (14)	0.0303 (3)
C7	0.2502 (2)	0.9735 (2)	0.36196 (14)	0.0322 (3)
H7	0.1752	1.0130	0.4081	0.039*
C8	−0.0389 (2)	0.7514 (2)	0.32528 (15)	0.0368 (4)
H8A	−0.0946	0.8292	0.3564	0.044*
H8B	−0.0423	0.6705	0.3831	0.044*
C9	−0.1601 (2)	0.6678 (2)	0.21434 (15)	0.0340 (3)
H9A	−0.0980	0.5975	0.1792	0.041*
H9B	−0.2862	0.5998	0.2335	0.041*
C10	−0.3048 (2)	0.7058 (2)	0.01819 (15)	0.0332 (3)
H10A	−0.4364	0.6494	0.0352	0.040*
H10B	−0.2520	0.6250	−0.0113	0.040*
C11	−0.3080 (3)	0.8258 (2)	−0.07429 (17)	0.0405 (4)
H11A	−0.4038	0.7716	−0.1387	0.049*
H11B	−0.3459	0.9139	−0.0418	0.049*
H2N2	−0.250 (3)	0.847 (3)	0.1598 (18)	0.038 (5)*
H1N2	−0.076 (3)	0.847 (3)	0.1116 (19)	0.044 (6)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.02607 (11)	0.03421 (11)	0.04535 (13)	0.01037 (8)	0.00784 (8)	−0.00554 (8)
Cl1	0.0558 (3)	0.0401 (2)	0.0530 (3)	0.0211 (2)	0.0134 (2)	0.00227 (19)
Cl2	0.0393 (2)	0.0533 (3)	0.0452 (2)	0.01947 (19)	0.00525 (18)	−0.00082 (19)
O1	0.0268 (6)	0.0394 (6)	0.0581 (8)	0.0071 (5)	0.0116 (5)	−0.0136 (6)
O2	0.0603 (9)	0.0430 (8)	0.0578 (9)	0.0196 (7)	0.0239 (7)	0.0151 (6)
N1	0.0259 (6)	0.0346 (7)	0.0343 (7)	0.0126 (5)	0.0074 (5)	0.0037 (5)
N2	0.0228 (6)	0.0289 (7)	0.0387 (7)	0.0072 (5)	0.0081 (5)	0.0012 (5)
C1	0.0305 (8)	0.0326 (8)	0.0314 (8)	0.0106 (6)	0.0036 (6)	0.0004 (6)
C2	0.0324 (8)	0.0423 (10)	0.0431 (10)	0.0063 (7)	0.0078 (7)	−0.0008 (8)
C3	0.0407 (10)	0.0398 (10)	0.0447 (10)	−0.0003 (8)	0.0015 (8)	0.0010 (8)
C4	0.0577 (12)	0.0348 (9)	0.0408 (10)	0.0066 (8)	0.0013 (8)	−0.0068 (7)
C5	0.0475 (10)	0.0378 (9)	0.0365 (9)	0.0168 (8)	0.0079 (7)	−0.0016 (7)
C6	0.0325 (8)	0.0318 (8)	0.0283 (8)	0.0125 (6)	0.0042 (6)	0.0031 (6)
C7	0.0341 (8)	0.0378 (8)	0.0310 (8)	0.0187 (7)	0.0094 (6)	0.0026 (6)
C8	0.0291 (8)	0.0454 (10)	0.0378 (9)	0.0121 (7)	0.0121 (7)	0.0079 (7)
C9	0.0260 (7)	0.0331 (8)	0.0436 (9)	0.0087 (6)	0.0100 (7)	0.0079 (7)
C10	0.0289 (8)	0.0314 (8)	0.0386 (9)	0.0088 (6)	0.0048 (6)	−0.0024 (6)
C11	0.0413 (9)	0.0382 (9)	0.0447 (10)	0.0173 (7)	0.0019 (8)	0.0021 (7)

Geometric parameters (Å, º)

Zn1—O1	1.9488 (12)	C3—H3	0.9300
Zn1—N1	2.0166 (13)	C4—C5	1.370 (3)
Zn1—Cl1	2.2313 (5)	C4—H4	0.9300
Zn1—Cl2	2.2421 (5)	C5—C6	1.407 (2)
O1—C1	1.319 (2)	C5—H5	0.9300
O2—C11	1.419 (2)	C6—C7	1.447 (2)
O2—H2O	0.9026	C7—H7	0.9300
N1—C7	1.279 (2)	C8—C9	1.511 (2)
N1—C8	1.466 (2)	C8—H8A	0.9700
N2—C10	1.491 (2)	C8—H8B	0.9700
N2—C9	1.493 (2)	C9—H9A	0.9700
N2—H2N2	0.89 (2)	C9—H9B	0.9700
N2—H1N2	0.85 (2)	C10—C11	1.504 (2)
C1—C2	1.410 (2)	C10—H10A	0.9700
C1—C6	1.421 (2)	C10—H10B	0.9700
C2—C3	1.374 (3)	C11—H11A	0.9700
C2—H2	0.9300	C11—H11B	0.9700
C3—C4	1.382 (3)
O1—Zn1—N1	96.12 (5)	C6—C5—H5	118.8
O1—Zn1—Cl1	111.64 (4)	C5—C6—C1	118.91 (15)
N1—Zn1—Cl1	111.43 (4)	C5—C6—C7	115.83 (15)
O1—Zn1—Cl2	110.77 (5)	C1—C6—C7	125.26 (15)
N1—Zn1—Cl2	113.54 (4)	N1—C7—C6	128.27 (15)
Cl1—Zn1—Cl2	112.33 (2)	N1—C7—H7	115.9
C1—O1—Zn1	124.88 (10)	C6—C7—H7	115.9
C11—O2—H2O	103.5	N1—C8—C9	112.34 (13)
C7—N1—C8	118.18 (14)	N1—C8—H8A	109.1
C7—N1—Zn1	120.86 (11)	C9—C8—H8A	109.1
C8—N1—Zn1	120.82 (11)	N1—C8—H8B	109.1
C10—N2—C9	112.14 (13)	C9—C8—H8B	109.1
C10—N2—H2N2	107.0 (13)	H8A—C8—H8B	107.9
C9—N2—H2N2	108.1 (13)	N2—C9—C8	111.94 (14)
C10—N2—H1N2	109.0 (15)	N2—C9—H9A	109.2
C9—N2—H1N2	109.2 (15)	C8—C9—H9A	109.2
H2N2—N2—H1N2	111.4 (19)	N2—C9—H9B	109.2
O1—C1—C2	118.60 (15)	C8—C9—H9B	109.2
O1—C1—C6	124.34 (14)	H9A—C9—H9B	107.9
C2—C1—C6	117.06 (15)	N2—C10—C11	111.83 (14)
C3—C2—C1	122.10 (17)	N2—C10—H10A	109.2
C3—C2—H2	119.0	C11—C10—H10A	109.2
C1—C2—H2	119.0	N2—C10—H10B	109.2
C2—C3—C4	120.79 (17)	C11—C10—H10B	109.2
C2—C3—H3	119.6	H10A—C10—H10B	107.9
C4—C3—H3	119.6	O2—C11—C10	111.64 (15)
C5—C4—C3	118.68 (17)	O2—C11—H11A	109.3
C5—C4—H4	120.7	C10—C11—H11A	109.3
C3—C4—H4	120.7	O2—C11—H11B	109.3
C4—C5—C6	122.45 (17)	C10—C11—H11B	109.3
C4—C5—H5	118.8	H11A—C11—H11B	108.0
N1—Zn1—O1—C1	−5.52 (15)	C4—C5—C6—C1	0.9 (3)
Cl1—Zn1—O1—C1	−121.48 (13)	C4—C5—C6—C7	−179.96 (17)
Cl2—Zn1—O1—C1	112.53 (14)	O1—C1—C6—C5	179.45 (16)
O1—Zn1—N1—C7	3.18 (14)	C2—C1—C6—C5	−0.5 (2)
Cl1—Zn1—N1—C7	119.32 (12)	O1—C1—C6—C7	0.4 (3)
Cl2—Zn1—N1—C7	−112.65 (12)	C2—C1—C6—C7	−179.57 (16)
O1—Zn1—N1—C8	−172.45 (12)	C8—N1—C7—C6	175.97 (15)
Cl1—Zn1—N1—C8	−56.31 (12)	Zn1—N1—C7—C6	0.2 (2)
Cl2—Zn1—N1—C8	71.72 (12)	C5—C6—C7—N1	177.91 (16)
Zn1—O1—C1—C2	−175.53 (13)	C1—C6—C7—N1	−3.0 (3)
Zn1—O1—C1—C6	4.5 (2)	C7—N1—C8—C9	142.43 (16)
O1—C1—C2—C3	179.81 (17)	Zn1—N1—C8—C9	−41.82 (18)
C6—C1—C2—C3	−0.2 (3)	C10—N2—C9—C8	179.64 (13)
C1—C2—C3—C4	0.6 (3)	N1—C8—C9—N2	−67.56 (18)
C2—C3—C4—C5	−0.2 (3)	C9—N2—C10—C11	−172.24 (14)
C3—C4—C5—C6	−0.5 (3)	N2—C10—C11—O2	68.96 (19)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O2—H2O···Cl1^i	0.90	2.77	3.469 (2)	135
N2—H1N2···O2^ii	0.85 (2)	2.26 (2)	2.987 (2)	143 (2)
N2—H2N2···O1^iii	0.89 (2)	1.90 (2)	2.747 (2)	160 (2)

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