Dichlorido{2-[3-(dimethyl­ammonio)­propyl­imino­meth­yl]phenolato}zinc(II) hemihydrate

The title complex, [ZnCl₂(C₁₂H₁₈N₂O)]·0.5H₂O, is a mononuclear zinc(II) compound derived from the zwitterionic form of the Schiff base 2-[3-(dimethyl­amino)propyl­imino­meth­yl]­phenol. The Zn^II atom is four-coordinated by the imine N and the phenolate O atoms of the Schiff base ligand, and by two chloride ions, in a distorted tetra­hedral coordination geometry. The dimethyl­ammonio group is disordered over two positions with site occupancies of 0.51 (3) and 0.49 (3). In the asymmetric unit, there is also a disordered water mol­ecule with a partial occupancy of 0.5. In the crystal structure, the water mol­ecules are linked to the Schiff base complex mol­ecules through inter­molecular N—H...O hydrogen bonds. Mol­ecules are further linked through additional inter­molecular N—H...O hydrogen bonds, forming chains running along the b axis.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.007 Å
• Disorder in main residue
• R factor = 0.041
• wR factor = 0.103
• Data-to-parameter ratio = 16.6

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT232_ALERT_2_B Hirshfeld Test Diff (M-X)  Zn1    --  Cl2     ..      30.05 su
PLAT242_ALERT_2_B Check Low       Ueq as Compared to Neighbors for        N2'

Alert level C
            Value of measurement temperature given =   298.000
            Value of melting point given =     0.000
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.00 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.43 Ratio
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Zn1
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N2
PLAT301_ALERT_3_C Main Residue  Disorder .........................      18.00 Perc.
PLAT341_ALERT_3_C Low Bond Precision on C-C Bonds (x 1000) Ang ...          7
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       0.50 Ratio
PLAT234_ALERT_4_C Large Hirshfeld Difference C8     --  C9      ..       0.12  Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           26.99
           From the CIF: _reflns_number_total               3426
           Count of symmetry unique reflns         1858
           Completeness (_total/calc)            184.39%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured      1568
           Fraction of Friedel pairs measured     0.844
           Are heavy atom types Z>Si present        yes
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          4
PLAT302_ALERT_4_G Anion/Solvent Disorder .........................      50.00 Perc.
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          1

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

   3 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
   4 ALERT type 3 Indicator that the structure quality may be low
   4 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Schiff bases have widely been used as versatile ligands in coordination chemistry (Biswas et al., 2008; Wu et al., 2008; Kawamoto et al., 2008; Ali et al., 2008; Habibi et al., 2007), and their metal complexes are of great interest in many fields (Chen et al., 2008; Yuan et al., 2007; Tomat et al., 2007; Darensbourg & Frantz, 2007). Zinc(II) is an important element in biological systems and functions as an active site of hydrolytic enzymes, such as carboxypeptidase and carbonic anhydrase where it is in a hard-donor coordination environment of nitrogen and oxygen ligands (Lipscomb & Sträter, 1996). Recently, we have reported some Schiff base complexes (Zhu & Yang, 2008a,b,c,d). In this paper, the synthesis and structural characterization of a new zinc(II) complex (Fig. 1) of the Schiff base ligand 2-[(3-dimethylaminopropylimino)methyl]phenol is reported.

The zinc(II) atom in the title compound is four-coordinated by the imine N and phenolate O atoms of the zwitterionic form of the Schiff base ligand, and by two Cl^- ions in a tetrahedral coordination geometry. The coordinate bond lengths (Table 1) are typical and comparable to the corresponding values observed in other similar zinc(II) Schiff base complexes (Zhu et al., 2007; Wei et al., 2007; Qiu, 2006a,b).

In the crystal structure, the water molecules are linked to the Schiff base complex molecules through intermolecular N–H···O hydrogen bonds (Table 2). The molecules are further linked through intermolecular N–H···O hydrogen bonds (Table 2), forming chains running along the b axis (Fig. 2).

Related literature

For a general background on the chemistry of Schiff base complexes, see: Ali et al. (2008); Biswas et al. (2008); Chen et al. (2008); Darensbourg & Frantz (2007); Habibi et al. (2007); Kawamoto et al. (2008); Lipscomb & Sträter (1996); Tomat et al. (2007); Wu et al. (2008); Yuan et al. (2007). For related structures, see: Zhu & Yang (2008a,b,c,d); Qiu (2006a,b); Wei et al. (2007); Zhu et al. (2007).

S2. Experimental

The Schiff base compound was prepared by the condensation of equimolar amounts of salicylaldehyde with N,N-dimethylpropane-1,3-diamine in a methanol solution. The complex was prepared by the following method: to an anhydrous methanol solution (5 ml) of ZnCl₂ (13.7 mg, 0.1 mmol) was added a methanol solution (10 ml) of the Schiff base compound (20.6 mg, 0.1 mmol) with stirring. The mixture was stirred for 30 min at room temperature and filtered. Upon keeping the filtrate in air for a few days, colourless block-shaped crystals were formed at the bottom of the vessel on slow evaporation of the solvent.

S3. Refinement

H atoms bound to C and N atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms, with C–H distances in the range 0.93–0.97 Å, N–H distances of 0.91 Å, and with U_iso(H) = 1.2U_eq(C,N) and 1.5U_eq(methyl C). The dimethylammmonium group is disordered over two distinct sites, with occupancies of 0.51 (3) and 0.49 (3), respectively. The lattice water molecule is also disordered, with an occupancy restrained to 0.50. The water H atoms were placed at calculated positions and refined with the O—H and H···H lengths constrained to 0.85 (1) and 1.37 (2) Å, respectively, and with the isotropic thermal parameter fixed at 0.08 Ų.

Computing details

Data collection: APEX2 (Bruker, 2004); cell refinement: SAINT (Bruker, 2004); data reduction: SAINT (Bruker, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The molecular structure of the title compound with ellipsoids drawn at the 30% probability level. Only the major component of disorder is shown.
	Fig. 2. The crystal packing of the title compound viewed along the c axis. Hydrogen atoms not involved in hydrogen bonding interactions (dashed lines) are omitted for clarity. Only the major component of disorder is shown.

Dichlorido{2-[3-(dimethylammonio)propyliminomethyl]phenolato}zinc(II) hemihydrate

Crystal data

[ZnCl2(C12H18N2O)]·0.5H2O	F(000) = 724
Mr = 351.58	Dx = 1.482 Mg m^−3
Orthorhombic, Pna21	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: P 2c -2n	Cell parameters from 3872 reflections
a = 13.335 (2) Å	θ = 2.4–25.3°
b = 16.384 (2) Å	µ = 1.89 mm^−1
c = 7.212 (1) Å	T = 298 K
V = 1575.7 (4) Å^3	Block, colorless
Z = 4	0.23 × 0.23 × 0.22 mm

Data collection

Bruker APEXII CCD area-detector diffractometer	3426 independent reflections
Radiation source: fine-focus sealed tube	2915 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ω scans	θmax = 27.0°, θmin = 2.0°
Absorption correction: multi-scan (SADABS; Sheldrick, 2004)	h = −17→17
Tmin = 0.650, Tmax = 0.661	k = −20→20
12635 measured reflections	l = −9→9

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)] = 0.041	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.103	w = 1/[σ^2(Fo^2) + (0.0381P)^2 + 0.643P] where P = (Fo^2 + 2Fc^2)/3
S = 1.08	(Δ/σ)max = 0.001
3426 reflections	Δρmax = 0.42 e Å^−3
206 parameters	Δρmin = −0.40 e Å^−3
4 restraints	Absolute structure: Flack (1983), 1569 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.03 (2)

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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	Occ. (<1)
Zn1	0.73458 (3)	1.10664 (2)	1.00222 (10)	0.04900 (15)
Cl1	0.59091 (11)	1.09513 (7)	1.1550 (2)	0.0746 (4)
Cl2	0.86270 (14)	1.03257 (11)	1.1229 (3)	0.1022 (5)
N1	0.7159 (3)	1.0824 (2)	0.7323 (5)	0.0449 (7)
O1	0.7749 (2)	1.21988 (16)	0.9610 (4)	0.0563 (8)
O2	0.9856 (5)	0.9368 (4)	0.1435 (12)	0.0704 (18)	0.50
C1	0.8128 (3)	1.2011 (2)	0.6371 (6)	0.0488 (9)
C2	0.8218 (3)	1.2425 (2)	0.8055 (6)	0.0464 (9)
C3	0.8817 (4)	1.3118 (3)	0.8081 (9)	0.0656 (13)
H3	0.8897	1.3401	0.9189	0.079*
C4	0.9288 (4)	1.3393 (3)	0.6546 (10)	0.0783 (16)
H4	0.9668	1.3868	0.6615	0.094*
C5	0.9217 (4)	1.2989 (3)	0.4892 (11)	0.0835 (17)
H5	0.9564	1.3172	0.3853	0.100*
C6	0.8631 (4)	1.2317 (3)	0.4807 (8)	0.0736 (14)
H6	0.8558	1.2049	0.3678	0.088*
C7	0.7537 (3)	1.1280 (3)	0.6068 (6)	0.0506 (10)
H7	0.7423	1.1129	0.4843	0.061*
C8	0.6601 (3)	1.0080 (2)	0.6728 (7)	0.0575 (11)
H8A	0.5968	1.0053	0.7389	0.069*
H8B	0.6455	1.0117	0.5413	0.069*
C9	0.7184 (4)	0.9327 (3)	0.7093 (7)	0.0674 (13)
H9A	0.6748	0.8858	0.6947	0.081*
H9B	0.7419	0.9335	0.8365	0.081*
N2	0.8576 (13)	0.8452 (7)	0.543 (2)	0.055 (4)	0.51 (3)
H2C	0.8090	0.8071	0.5247	0.066*	0.51 (3)
C10	0.8059 (4)	0.9240 (3)	0.5831 (9)	0.0800 (18)	0.51 (3)
H10A	0.8570	0.9608	0.6296	0.096*	0.51 (3)
H10B	0.7849	0.9456	0.4641	0.096*	0.51 (3)
C11	0.9122 (17)	0.8214 (9)	0.713 (4)	0.091 (8)	0.51 (3)
H11A	0.8683	0.8257	0.8176	0.137*	0.51 (3)
H11B	0.9687	0.8569	0.7296	0.137*	0.51 (3)
H11C	0.9351	0.7661	0.7008	0.137*	0.51 (3)
C12	0.9244 (10)	0.8403 (9)	0.389 (3)	0.082 (6)	0.51 (3)
H12A	0.9523	0.7864	0.3816	0.123*	0.51 (3)
H12B	0.9775	0.8793	0.4036	0.123*	0.51 (3)
H12C	0.8883	0.8519	0.2765	0.123*	0.51 (3)
N2'	0.8443 (12)	0.8327 (9)	0.641 (4)	0.071 (5)	0.49 (3)
H2'A	0.7970	0.7970	0.5998	0.085*	0.49 (3)
C10'	0.8059 (4)	0.9240 (3)	0.5831 (9)	0.0800 (18)	0.49 (3)
H10C	0.8566	0.9650	0.6072	0.096*	0.49 (3)
H10D	0.7860	0.9265	0.4538	0.096*	0.49 (3)
C11'	0.8661 (16)	0.8106 (11)	0.824 (4)	0.101 (8)	0.49 (3)
H11D	0.8812	0.7534	0.8288	0.152*	0.49 (3)
H11E	0.8091	0.8220	0.9010	0.152*	0.49 (3)
H11F	0.9228	0.8413	0.8668	0.152*	0.49 (3)
C12'	0.9351 (17)	0.8164 (14)	0.534 (6)	0.139 (12)	0.49 (3)
H12D	0.9592	0.7626	0.5629	0.209*	0.49 (3)
H12E	0.9855	0.8559	0.5658	0.209*	0.49 (3)
H12F	0.9203	0.8199	0.4044	0.209*	0.49 (3)
H2A	0.984 (7)	0.973 (5)	0.228 (11)	0.080*	0.50
H2B	0.930 (4)	0.911 (5)	0.146 (15)	0.080*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0640 (3)	0.0390 (2)	0.0440 (2)	−0.00734 (18)	0.0112 (3)	−0.0061 (3)
Cl1	0.0750 (8)	0.0720 (8)	0.0768 (8)	−0.0113 (6)	0.0324 (7)	−0.0094 (6)
Cl2	0.1140 (13)	0.1004 (11)	0.0921 (11)	−0.0145 (9)	−0.0136 (10)	0.0143 (9)
N1	0.0476 (18)	0.0393 (16)	0.0478 (18)	0.0030 (14)	0.0062 (15)	−0.0058 (14)
O1	0.0774 (18)	0.0361 (12)	0.055 (2)	−0.0102 (12)	0.0190 (14)	−0.0142 (12)
O2	0.056 (4)	0.054 (4)	0.102 (6)	0.011 (3)	0.005 (4)	0.015 (4)
C1	0.052 (2)	0.0417 (19)	0.053 (2)	0.0019 (17)	0.0052 (18)	0.0038 (18)
C2	0.051 (2)	0.0308 (17)	0.058 (2)	−0.0004 (16)	0.0125 (19)	0.0006 (16)
C3	0.067 (3)	0.042 (2)	0.088 (4)	−0.008 (2)	0.011 (3)	−0.014 (2)
C4	0.064 (3)	0.048 (2)	0.123 (5)	−0.009 (2)	0.031 (3)	0.009 (3)
C5	0.079 (3)	0.072 (3)	0.100 (4)	0.002 (2)	0.041 (4)	0.019 (4)
C6	0.088 (3)	0.070 (3)	0.063 (3)	0.001 (2)	0.030 (3)	0.010 (3)
C7	0.062 (3)	0.049 (2)	0.041 (2)	−0.0007 (18)	0.0022 (19)	−0.0092 (19)
C8	0.059 (3)	0.046 (2)	0.068 (3)	−0.0111 (19)	0.001 (2)	−0.018 (2)
C9	0.098 (4)	0.043 (2)	0.061 (3)	−0.021 (2)	−0.006 (3)	−0.010 (2)
N2	0.070 (7)	0.026 (3)	0.069 (9)	−0.004 (3)	−0.020 (7)	−0.001 (5)
C10	0.078 (3)	0.037 (2)	0.124 (5)	−0.002 (2)	−0.008 (3)	−0.020 (3)
C11	0.085 (14)	0.052 (7)	0.136 (19)	0.000 (7)	−0.051 (14)	0.024 (9)
C12	0.072 (8)	0.049 (7)	0.125 (14)	0.020 (5)	0.017 (9)	−0.028 (7)
N2'	0.067 (8)	0.044 (7)	0.101 (14)	0.004 (5)	−0.006 (9)	−0.029 (8)
C10'	0.078 (3)	0.037 (2)	0.124 (5)	−0.002 (2)	−0.008 (3)	−0.020 (3)
C11'	0.094 (12)	0.051 (8)	0.16 (2)	0.014 (8)	−0.054 (13)	−0.027 (10)
C12'	0.094 (12)	0.127 (16)	0.20 (4)	0.010 (12)	0.068 (19)	−0.002 (19)

Geometric parameters (Å, º)

Zn1—O1	1.954 (3)	C9—C10	1.487 (8)
Zn1—N1	2.003 (4)	C9—H9A	0.9700
Zn1—Cl1	2.2182 (13)	C9—H9B	0.9700
Zn1—Cl2	2.2692 (18)	N2—C12	1.430 (19)
N1—C7	1.277 (6)	N2—C11	1.47 (2)
N1—C8	1.491 (5)	N2—C10	1.491 (15)
O1—C2	1.336 (5)	N2—H2C	0.9100
O2—H2A	0.852 (10)	C10—H10A	0.9700
O2—H2B	0.848 (10)	C10—H10B	0.9700
C1—C2	1.396 (6)	C11—H11A	0.9600
C1—C6	1.405 (6)	C11—H11B	0.9600
C1—C7	1.451 (6)	C11—H11C	0.9600
C2—C3	1.389 (6)	C12—H12A	0.9600
C3—C4	1.350 (8)	C12—H12B	0.9600
C3—H3	0.9300	C12—H12C	0.9600
C4—C5	1.368 (9)	N2'—C11'	1.40 (3)
C4—H4	0.9300	N2'—C12'	1.46 (2)
C5—C6	1.352 (7)	N2'—H2'A	0.9100
C5—H5	0.9300	C11'—H11D	0.9600
C6—H6	0.9300	C11'—H11E	0.9600
C7—H7	0.9300	C11'—H11F	0.9600
C8—C9	1.481 (7)	C12'—H12D	0.9600
C8—H8A	0.9700	C12'—H12E	0.9600
C8—H8B	0.9700	C12'—H12F	0.9600
O1—Zn1—N1	94.29 (13)	C10—C9—H9B	109.1
O1—Zn1—Cl1	113.19 (9)	H9A—C9—H9B	107.8
N1—Zn1—Cl1	111.04 (11)	C12—N2—C11	108.9 (14)
O1—Zn1—Cl2	111.03 (11)	C12—N2—C10	119.2 (9)
N1—Zn1—Cl2	111.10 (11)	C11—N2—C10	107.3 (12)
Cl1—Zn1—Cl2	114.48 (7)	C12—N2—H2C	106.9
C7—N1—C8	118.1 (4)	C11—N2—H2C	106.9
C7—N1—Zn1	121.6 (3)	C10—N2—H2C	106.9
C8—N1—Zn1	120.3 (3)	C9—C10—N2	124.4 (8)
C2—O1—Zn1	121.3 (2)	C9—C10—H10A	106.2
H2A—O2—H2B	108 (3)	N2—C10—H10A	106.2
C2—C1—C6	119.0 (4)	C9—C10—H10B	106.2
C2—C1—C7	125.4 (4)	N2—C10—H10B	106.2
C6—C1—C7	115.6 (4)	H10A—C10—H10B	106.4
O1—C2—C3	119.0 (4)	N2—C11—H11A	109.5
O1—C2—C1	123.7 (3)	N2—C11—H11B	109.5
C3—C2—C1	117.2 (4)	H11A—C11—H11B	109.5
C4—C3—C2	122.0 (5)	N2—C11—H11C	109.5
C4—C3—H3	119.0	H11A—C11—H11C	109.5
C2—C3—H3	119.0	H11B—C11—H11C	109.5
C3—C4—C5	121.4 (5)	N2—C12—H12A	109.5
C3—C4—H4	119.3	N2—C12—H12B	109.5
C5—C4—H4	119.3	H12A—C12—H12B	109.5
C6—C5—C4	118.3 (5)	N2—C12—H12C	109.5
C6—C5—H5	120.8	H12A—C12—H12C	109.5
C4—C5—H5	120.8	H12B—C12—H12C	109.5
C5—C6—C1	122.0 (6)	C11'—N2'—C12'	106.1 (19)
C5—C6—H6	119.0	C11'—N2'—H2'A	106.6
C1—C6—H6	119.0	C12'—N2'—H2'A	106.6
N1—C7—C1	126.2 (4)	N2'—C11'—H11D	109.5
N1—C7—H7	116.9	N2'—C11'—H11E	109.5
C1—C7—H7	116.9	H11D—C11'—H11E	109.5
C9—C8—N1	111.5 (4)	N2'—C11'—H11F	109.5
C9—C8—H8A	109.3	H11D—C11'—H11F	109.5
N1—C8—H8A	109.3	H11E—C11'—H11F	109.5
C9—C8—H8B	109.3	N2'—C12'—H12D	109.5
N1—C8—H8B	109.3	N2'—C12'—H12E	109.5
H8A—C8—H8B	108.0	H12D—C12'—H12E	109.5
C8—C9—C10	112.6 (4)	N2'—C12'—H12F	109.5
C8—C9—H9A	109.1	H12D—C12'—H12F	109.5
C10—C9—H9A	109.1	H12E—C12'—H12F	109.5
C8—C9—H9B	109.1

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2′—H2′A···O1^i	0.91	1.88	2.762 (14)	164
N2—H2C···O1^i	0.91	1.87	2.773 (12)	170

Symmetry code: (i) −x+3/2, y−1/2, z−1/2.