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Acta Cryst. (2009). E65, m1352    [ doi:10.1107/S1600536809040872 ]

Hexaaquamagnesium(II) bis{[N-(4-methoxy-2-oxidobenzylidene)glycylglycinato(3-)]cuprate(II)} hexahydrate

J. Jiang, Y. Lu, L. Yuan and W. Liu

Abstract top

In the title complex, [Mg(H2O)6][Cu(C12H11N2O5)]2·6H2O, the CuII atoms lie at the center of the square plane of triple negatively charged O,N,N',O'-tetradentate Schiff base ligands, which are coordinated by one phenolate O atom, one imine N atom, one deprotonated amide N atom and one carboxylate O atom. The MgII center, which sits on an inversion center, is coordinated by six aqua ligands and exhibits a slightly distorted octahedral conformation. The asymmetric unit consists of an [N-(4-methoxy-2-oxidobenzylidene)glycylglycinato]cuprate(II) anion, one half of an [Mg(H2O)6]2+ cation and three free water molecules. The cations and anions form columns by O-H...O hydrogen bonds.

Comment top

The Schiff bases are widely employed as ligands in coordination chemistry. These ligands are readily available, versatile, they exhibit various denticities and functionalities (Vigato et al., 2007; Gupta et al., 2009). Moreover, the number, the nature, and the relative position of the donor atoms of a Schiff base ligand allow a good control over the stereochemistry of the metallic centers, as well as over the number of the metal ions within homo- and heteronuclear complexes (Vigato et al., 2008; Sakamoto et al., 2001). Now we report the synthesis and structure of CuII—MgII Schiff base complex derived from glycylglycine and 4-methoxy-salicylaldehyde.

The heteronuclear complex (I) crystallizes in the triclinic space group P1. The asymmetric unit consists of one [CuL]- anion (L is a Schiff base derived from glycylglycine and 4-methoxy-salicylaldehyde), one half of the Mg(H2O)62+ cation [Mg1, O6, O7, O8] and three uncoordinated water molecules [O9, O10, O11] in the complex (I) (Fig. 1). The deprotonated Schiff base is a triple negatively charged tetradentate ONNO ligand, coordinating to the CuII atom by one phenolate O atom [O1] (Cu1—O1 = 1.880 (2) Å), one imine N atom [N1] (Cu1—N1 = 1.920 (2) Å), one deprotonated amide N atom [N2] (Cu1—N2 = 1.892 (2) Å) and one carboxylato O atom [O3] (Cu1—O3 = 1.980 (2) Å). [CuL]- exhibits approximately a square-planar structure. The CuII atom is in a slightly distorted square-planar environment with four donor atoms deviating from their mean plane by -0.0506 (9) Å (N1), +0.0626 (9) Å (N2), +0.0513 (8) Å (O1) and -0.0496 (9) Å (O3) (observed bond angles vary from 83.5 (1)° to 96.9 (1)°). The benzene ring [C1–C6] and the chelate ring [O1, C1, C6, C7, N1, Cu1] are almost coplanar with a dihedral angle of 0.11 (9)°, suggesting a large π-electron delocalization. The MgII atom lies on an inversion center and the coordination by six aqua ligands exhibits a slightly distorted octahedral environment. The six Mg—O bonds in the structure are in the range of 2.059 (2) - 2.063 (2) Å. In the crystal structure, the [CuL]- anions and [Mg(H2O)6]2+ cations each form columns by hydrogen bonds along the a-axis (Fig. 2, Table 1).

Related literature top

For structures of Schiff base analogues, see: Gupta et al.(2009); Vigato et al. (2007). For structures of Schiff base heteronuclear complexes, see: Jiang et al. (2009); Sakamoto et al. (2001); Vigato & Tamburini (2008); Zhang et al. (2008).

Experimental top

Glycylglycine (5 mmol), 4-methoxy-salicylaldehyde (5 mmol) and NaOH (10 mmol) were dissolved in MeOH/H2O (30 ml, v: v = 1: 1) and refluxed for 30 min. Then Cu(ClO4)2.6H2O (5 mmol) was added to the solution and the resulting solution was adjusted to 9–11 by 5 mol/L NaOH solution. After stirring at room temperature for another 1 hr, MgCl2.6H2O (2.5 mmol) was added. A violet precipitate was obtained immediately. After stirring for 30 min and then filtered, the precipitate was recrystallized in water. The violet crystals of complex (I) suitable for an X-ray diffraction analyses were obtained after 1 week.

Refinement top

The water H atoms were located in a difference Fourier map and refined with restraints: O—H = 0.85 Å and Uiso(H) =1.5Ueq(O). All other H atoms were positioned geometrically and constrained as riding atoms, with C—H distances of 0.93–0.97 Å and Uiso(H) set to 1.2 or 1.5Ueq(C) of the parent atom.

Computing details top

Data collection: SMART (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SHELXTL (Sheldrick, 2008); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008) and DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of (I), with atom labels and 50% probability displacement ellipsoids. Unlabeled atoms are related to labeled atoms by the symmetry code (-x + 1, -y + 2, -z + 1).
[Figure 2] Fig. 2. A packing diagram of (I), viewed down the a-axis, showing a separated column stacking structure connected by O—H···O hydrogen bonds (dashed lines).
Hexaaquamagnesium(II) bis{[N-(4-methoxy-2-oxidobenzylidene)glycylglycinato(3-)]cuprate(II)} hexahydrate top
Crystal data top
[Mg(H2O)6][Cu(C12H11N2O5)]2·6H2OZ = 1
Mr = 894.04F(000) = 464
Triclinic, P1Dx = 1.592 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 7.8606 (14) ÅCell parameters from 7186 reflections
b = 10.933 (2) Åθ = 1.0–28.3°
c = 11.539 (2) ŵ = 1.25 mm−1
α = 76.650 (2)°T = 296 K
β = 76.685 (2)°Block, violet
γ = 80.737 (2)°0.30 × 0.28 × 0.25 mm
V = 932.8 (3) Å3
Data collection top
Bruker SMART APEX CCD
diffractometer		2836 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.084
φ and ω scansθmax = 25.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		h = −9→9
Tmin = 0.696, Tmax = 0.736k = −12→12
6808 measured reflectionsl = −13→13
3262 independent reflections
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.036Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.097H atoms treated by a mixture of independent and constrained refinement
S = 1.03 w = 1/[σ2(Fo2) + (0.0593P)2]
where P = (Fo2 + 2Fc2)/3
3262 reflections(Δ/σ)max = 0.001
278 parametersΔρmax = 0.76 e Å−3
18 restraintsΔρmin = −0.57 e Å−3
Crystal data top
[Mg(H2O)6][Cu(C12H11N2O5)]2·6H2Oγ = 80.737 (2)°
Mr = 894.04V = 932.8 (3) Å3
Triclinic, P1Z = 1
a = 7.8606 (14) ÅMo Kα radiation
b = 10.933 (2) ŵ = 1.25 mm−1
c = 11.539 (2) ÅT = 296 K
α = 76.650 (2)°0.30 × 0.28 × 0.25 mm
β = 76.685 (2)°
Data collection top
Bruker SMART APEX CCD
diffractometer		3262 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 2004)		2836 reflections with I > 2σ(I)
Tmin = 0.696, Tmax = 0.736Rint = 0.084
6808 measured reflectionsθmax = 25.0°
Refinement top
R[F2 > 2σ(F2)] = 0.036H atoms treated by a mixture of independent and constrained refinement
wR(F2) = 0.097Δρmax = 0.76 e Å−3
S = 1.03Δρmin = −0.57 e Å−3
3262 reflectionsAbsolute structure: ?
278 parametersFlack parameter: ?
18 restraintsRogers parameter: ?
Special details top

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 (Å2) top
xyzUiso*/Ueq
Mg10.50001.00000.50000.0274 (3)
Cu10.53658 (3)0.70272 (3)0.98705 (2)0.02798 (13)
C10.7984 (3)0.5135 (2)0.8983 (2)0.0278 (5)
C20.9093 (3)0.4662 (2)0.8009 (2)0.0318 (5)
H20.91060.51160.72190.038*
C31.0174 (3)0.3528 (2)0.8201 (3)0.0338 (6)
C41.0200 (3)0.2837 (2)0.9381 (3)0.0378 (6)
H41.09470.20890.95100.045*
C50.9110 (3)0.3276 (2)1.0342 (3)0.0357 (6)
H50.91200.28081.11240.043*
C60.7962 (3)0.4422 (2)1.0192 (2)0.0297 (5)
C70.6919 (3)0.4804 (2)1.1269 (2)0.0311 (5)
H70.70450.42831.20120.037*
C80.4821 (3)0.6142 (3)1.2436 (2)0.0354 (6)
H8A0.56250.62011.29400.043*
H8B0.40770.54881.28750.043*
C90.3683 (3)0.7412 (2)1.2172 (2)0.0289 (5)
C100.2895 (3)0.9088 (2)1.0529 (2)0.0319 (5)
H10A0.32560.97901.07620.038*
H10B0.16420.90651.08440.038*
C110.3290 (3)0.9256 (2)0.9147 (2)0.0308 (5)
C121.1256 (4)0.3610 (3)0.6070 (3)0.0504 (7)
H12A1.00810.36950.59300.076*
H12B1.20290.31080.55400.076*
H12C1.16430.44320.59110.076*
N10.5819 (3)0.58115 (19)1.12892 (18)0.0301 (4)
N20.3860 (3)0.79083 (19)1.10172 (18)0.0315 (5)
O10.6989 (2)0.62339 (15)0.87217 (15)0.0315 (4)
O30.4460 (2)0.84413 (16)0.86727 (15)0.0352 (4)
O40.2500 (2)1.01549 (17)0.85495 (16)0.0434 (5)
O20.2727 (2)0.78645 (17)1.30527 (15)0.0370 (4)
O51.1276 (2)0.30083 (17)0.73004 (18)0.0458 (5)
O60.4664 (2)1.10040 (18)0.63586 (15)0.0376 (4)
H6A0.553 (3)1.120 (3)0.656 (3)0.056*
H6B0.394 (3)1.077 (3)0.702 (2)0.056*
O70.2365 (2)1.0350 (2)0.49409 (17)0.0423 (5)
H7A0.159 (4)1.017 (3)0.557 (2)0.063*
H7B0.194 (4)1.096 (2)0.448 (2)0.063*
O80.4514 (3)0.83655 (18)0.62765 (16)0.0423 (5)
H8C0.393 (4)0.785 (3)0.616 (3)0.063*
H8D0.442 (5)0.836 (3)0.7002 (18)0.063*
O90.8995 (3)0.7896 (2)0.68699 (18)0.0479 (5)
H9A0.908 (5)0.855 (2)0.712 (3)0.072*
H9B0.837 (4)0.742 (3)0.737 (3)0.072*
O101.0000 (3)0.9857 (2)0.28950 (19)0.0462 (5)
H10C1.072 (4)0.922 (2)0.298 (3)0.069*
H10D0.934 (4)0.984 (3)0.246 (3)0.069*
O110.2361 (3)0.6905 (2)0.56744 (19)0.0483 (5)
H11A0.145 (3)0.724 (3)0.602 (3)0.072*
H11B0.249 (4)0.708 (3)0.4918 (16)0.072*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg10.0289 (6)0.0339 (6)0.0190 (5)−0.0054 (4)−0.0024 (4)−0.0058 (4)
Cu10.03038 (19)0.03127 (19)0.01925 (18)0.00204 (12)−0.00343 (12)−0.00437 (12)
C10.0263 (11)0.0252 (11)0.0331 (13)−0.0035 (9)−0.0082 (10)−0.0054 (10)
C20.0310 (12)0.0309 (12)0.0332 (14)−0.0027 (10)−0.0070 (10)−0.0061 (10)
C30.0276 (12)0.0311 (12)0.0450 (15)−0.0024 (10)−0.0071 (11)−0.0135 (11)
C40.0351 (13)0.0284 (12)0.0506 (17)0.0032 (10)−0.0149 (12)−0.0075 (11)
C50.0374 (13)0.0292 (12)0.0409 (15)−0.0032 (10)−0.0161 (12)−0.0003 (11)
C60.0287 (12)0.0280 (12)0.0338 (13)−0.0039 (9)−0.0105 (10)−0.0042 (10)
C70.0321 (12)0.0335 (13)0.0275 (13)−0.0082 (10)−0.0113 (10)0.0023 (10)
C80.0336 (13)0.0496 (15)0.0211 (12)−0.0027 (11)−0.0070 (10)−0.0031 (11)
C90.0267 (11)0.0408 (13)0.0230 (12)−0.0097 (10)−0.0048 (9)−0.0104 (10)
C100.0386 (13)0.0327 (13)0.0226 (12)−0.0009 (10)−0.0006 (10)−0.0096 (10)
C110.0338 (13)0.0300 (12)0.0263 (13)−0.0012 (10)−0.0015 (10)−0.0070 (10)
C120.0512 (17)0.0503 (17)0.0473 (18)0.0053 (13)−0.0041 (14)−0.0182 (14)
N10.0284 (10)0.0366 (11)0.0248 (10)−0.0029 (8)−0.0071 (8)−0.0038 (8)
N20.0365 (11)0.0345 (11)0.0217 (10)−0.0004 (9)−0.0042 (9)−0.0062 (8)
O10.0340 (9)0.0305 (8)0.0250 (9)0.0041 (7)−0.0038 (7)−0.0033 (7)
O30.0448 (10)0.0347 (9)0.0193 (9)0.0084 (7)−0.0018 (7)−0.0053 (7)
O40.0514 (11)0.0391 (10)0.0290 (10)0.0146 (8)−0.0035 (8)−0.0040 (8)
O20.0370 (9)0.0524 (11)0.0215 (9)−0.0036 (8)−0.0024 (7)−0.0116 (8)
O50.0446 (11)0.0409 (10)0.0486 (12)0.0102 (8)−0.0060 (9)−0.0161 (9)
O60.0400 (10)0.0481 (11)0.0269 (9)−0.0122 (8)0.0019 (8)−0.0154 (8)
O70.0303 (9)0.0610 (12)0.0288 (10)−0.0006 (8)−0.0027 (8)−0.0019 (9)
O80.0591 (12)0.0455 (11)0.0240 (9)−0.0185 (9)−0.0083 (9)−0.0016 (8)
O90.0487 (12)0.0496 (12)0.0385 (12)−0.0082 (9)−0.0032 (9)0.0015 (9)
O100.0365 (11)0.0617 (13)0.0366 (11)0.0040 (9)−0.0026 (8)−0.0140 (10)
O110.0530 (12)0.0529 (12)0.0393 (12)−0.0108 (10)−0.0093 (10)−0.0067 (10)
Geometric parameters (Å, °) top
Mg1—O7i2.0591 (18)C8—H8A0.9700
Mg1—O72.0591 (18)C8—H8B0.9700
Mg1—O62.0598 (17)C9—O21.266 (3)
Mg1—O6i2.0599 (17)C9—N21.302 (3)
Mg1—O82.0625 (18)C10—N21.451 (3)
Mg1—O8i2.0626 (18)C10—C111.526 (3)
Cu1—O11.8797 (17)C10—H10A0.9700
Cu1—N21.892 (2)C10—H10B0.9700
Cu1—N11.920 (2)C11—O41.231 (3)
Cu1—O31.9799 (16)C11—O31.292 (3)
C1—O11.336 (3)C12—O51.422 (4)
C1—C21.401 (3)C12—H12A0.9600
C1—C61.430 (3)C12—H12B0.9600
C2—C31.389 (3)C12—H12C0.9600
C2—H20.9300O6—H6A0.840 (17)
C3—O51.361 (3)O6—H6B0.851 (17)
C3—C41.400 (4)O7—H7A0.840 (17)
C4—C51.368 (4)O7—H7B0.833 (17)
C4—H40.9300O8—H8C0.831 (17)
C5—C61.422 (3)O8—H8D0.822 (17)
C5—H50.9300O9—H9A0.848 (18)
C6—C71.432 (4)O9—H9B0.810 (18)
C7—N11.288 (3)O10—H10C0.826 (18)
C7—H70.9300O10—H10D0.810 (17)
C8—N11.466 (3)O11—H11A0.813 (18)
C8—C91.533 (3)O11—H11B0.835 (18)
O7i—Mg1—O7179.999 (1)C9—C8—H8A109.7
O7i—Mg1—O688.05 (8)N1—C8—H8B109.7
O7—Mg1—O691.95 (8)C9—C8—H8B109.7
O7i—Mg1—O6i91.95 (8)H8A—C8—H8B108.2
O7—Mg1—O6i88.05 (8)O2—C9—N2127.6 (2)
O6—Mg1—O6i180.0O2—C9—C8119.1 (2)
O7i—Mg1—O890.55 (8)N2—C9—C8113.2 (2)
O7—Mg1—O889.45 (8)N2—C10—C11107.92 (19)
O6—Mg1—O890.60 (8)N2—C10—H10A110.1
O6i—Mg1—O889.40 (8)C11—C10—H10A110.1
O7i—Mg1—O8i89.45 (8)N2—C10—H10B110.1
O7—Mg1—O8i90.55 (8)C11—C10—H10B110.1
O6—Mg1—O8i89.40 (8)H10A—C10—H10B108.4
O6i—Mg1—O8i90.60 (8)O4—C11—O3123.8 (2)
O8—Mg1—O8i180.000 (1)O4—C11—C10118.8 (2)
O1—Cu1—N2175.66 (8)O3—C11—C10117.4 (2)
O1—Cu1—N196.90 (8)O5—C12—H12A109.5
N2—Cu1—N183.79 (9)O5—C12—H12B109.5
O1—Cu1—O395.95 (7)H12A—C12—H12B109.5
N2—Cu1—O383.51 (8)O5—C12—H12C109.5
N1—Cu1—O3167.03 (8)H12A—C12—H12C109.5
O1—C1—C2117.5 (2)H12B—C12—H12C109.5
O1—C1—C6123.6 (2)C7—N1—C8121.6 (2)
C2—C1—C6118.9 (2)C7—N1—Cu1124.53 (18)
C3—C2—C1121.2 (2)C8—N1—Cu1113.87 (16)
C3—C2—H2119.4C9—N2—C10124.0 (2)
C1—C2—H2119.4C9—N2—Cu1119.48 (17)
O5—C3—C2124.4 (2)C10—N2—Cu1116.46 (15)
O5—C3—C4115.0 (2)C1—O1—Cu1125.02 (15)
C2—C3—C4120.6 (2)C11—O3—Cu1114.46 (15)
C5—C4—C3119.0 (2)C3—O5—C12118.7 (2)
C5—C4—H4120.5Mg1—O6—H6A121 (2)
C3—C4—H4120.5Mg1—O6—H6B118 (2)
C4—C5—C6122.6 (2)H6A—O6—H6B106 (2)
C4—C5—H5118.7Mg1—O7—H7A121 (2)
C6—C5—H5118.7Mg1—O7—H7B124 (2)
C5—C6—C1117.7 (2)H7A—O7—H7B108 (2)
C5—C6—C7117.5 (2)Mg1—O8—H8C121 (2)
C1—C6—C7124.7 (2)Mg1—O8—H8D120 (2)
N1—C7—C6125.1 (2)H8C—O8—H8D112 (3)
N1—C7—H7117.4H9A—O9—H9B113 (3)
C6—C7—H7117.4H10C—O10—H10D114 (3)
N1—C8—C9109.61 (19)H11A—O11—H11B114 (3)
N1—C8—H8A109.7
Symmetry codes: (i) −x+1, −y+2, −z+1.
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O6—H6B···O40.85 (2)1.91 (2)2.755 (3)175 (3)
O6—H6A···O2ii0.84 (2)2.02 (2)2.836 (2)165 (3)
O7—H7A···O10i0.84 (2)1.91 (2)2.734 (3)165 (3)
O7—H7B···O9i0.83 (2)1.96 (2)2.776 (3)166 (3)
O8—H8C···O110.83 (2)1.98 (2)2.797 (3)169 (3)
O8—H8D···O30.82 (2)1.96 (2)2.775 (2)173 (3)
O9—H9A···O10iii0.85 (2)1.99 (2)2.787 (3)157 (3)
O9—H9B···O10.81 (2)2.01 (2)2.816 (3)174 (4)
O10—H10C···O2iv0.83 (2)1.99 (2)2.805 (3)171 (4)
O10—H10D···O4i0.81 (2)2.05 (2)2.857 (3)176 (4)
O11—H11A···O9v0.81 (2)2.05 (2)2.857 (3)172 (4)
O11—H11B···O2vi0.84 (2)2.10 (2)2.927 (3)170 (4)
Symmetry codes: (ii) −x+1, −y+2, −z+2; (i) −x+1, −y+2, −z+1; (iii) −x+2, −y+2, −z+1; (iv) x+1, y, z−1; (v) x−1, y, z; (vi) x, y, z−1.
Table 1
Hydrogen-bond geometry (Å, °) top
D—H···AD—HH···AD···AD—H···A
O6—H6B···O40.85 (2)1.91 (2)2.755 (3)175 (3)
O6—H6A···O2i0.84 (2)2.02 (2)2.836 (2)165 (3)
O7—H7A···O10ii0.84 (2)1.91 (2)2.734 (3)165 (3)
O7—H7B···O9ii0.83 (2)1.96 (2)2.776 (3)166 (3)
O8—H8C···O110.83 (2)1.98 (2)2.797 (3)169 (3)
O8—H8D···O30.82 (2)1.96 (2)2.775 (2)173 (3)
O9—H9A···O10iii0.85 (2)1.99 (2)2.787 (3)157 (3)
O9—H9B···O10.81 (2)2.01 (2)2.816 (3)174 (4)
O10—H10C···O2iv0.83 (2)1.99 (2)2.805 (3)171 (4)
O10—H10D···O4ii0.81 (2)2.05 (2)2.857 (3)176 (4)
O11—H11A···O9v0.81 (2)2.05 (2)2.857 (3)172 (4)
O11—H11B···O2vi0.84 (2)2.10 (2)2.927 (3)170 (4)
Symmetry codes: (i) −x+1, −y+2, −z+2; (ii) −x+1, −y+2, −z+1; (iii) −x+2, −y+2, −z+1; (iv) x+1, y, z−1; (v) x−1, y, z; (vi) x, y, z−1.
Acknowledgements top

This work was supported by SRF for ROCS, SEM and Yangzhou University.

references
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