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Journal logoCRYSTALLOGRAPHIC
COMMUNICATIONS
ISSN: 2056-9890
Volume 71| Part 3| March 2015| Pages 321-323
doi:10.1107/S2056989015003758

Crystal structure of tetra­aquabis(1,3-di­methyl-2,6-dioxo-3,7-di­hydro-1H-purin-9-ido)magnesium

CROSSMARK_Color_square_no_text.svg
Yabin Shia and Benyong Loua*

aDepartment of Chemistry and Chemical Engineering, Minjiang University, Fuzhou 350108, People's Republic of China
*Correspondence e-mail: lby@mju.edu.cn

Edited by A. J. Lough, University of Toronto, Canada (Received 3 February 2015; accepted 23 February 2015; online 28 February 2015)

The title complex, [Mg(C7H7N4O2)2(H2O)4], lies across an inversion centre and the MgII atom is coordinated in a slightly distorted octa­hedral environment by four aqua ligands in the equatorial sites and two 1,3-dimethyl-2,6-dioxo-3,7-di­hydro-1H-purin-9-ide ligands, through imidazole ring N atoms, in the axial sites. An intra­molecular O—H⋯O hydrogen bond forms an S(7) graph-set motif. In the crystal, O—H⋯O and O—H⋯N hydrogen bonds link complex mol­ecules forming a three-dimensional network incorporating R42(8) and R22(18) graph-set motifs.

CCDC reference: 1050901

1. Chemical context

Co-crystallization represents a crystal engineering approach for modifying properties of active pharmaceutical ingredients (APIs) (Sun, 2013[Sun, C. C. (2013). Expert Opin. Drug Deliv. 10, 201-213.]). Metal coordination is an alternative strategy without changing chemical structures of APIs (Ma & Moulton, 2007[Ma, Z. & Moulton, B. (2007). Cryst. Growth Des. 7, 196-198.]). Theophylline is a methylxanthine drug in the treatment of asthma and chronic obstructive pulmonary disease (Barnes, 2003[Barnes, P. J. (2003). Am. J. Respir. Crit. Care Med. 167, 813-818.]). In this study, we reacted theophylline with the MgII ion in a basic solution to give rise to a tetra­aqua mononuclear MgII complex, (I)[link].

[Scheme 1]

2. Structural commentary

The mol­ecular structure of (I)[link] is shown in Fig. 1[link]. The complex lies across an inversion centre and the MgII atom is coordin­ated in a slightly distorted octa­hedral environment (Table 1[link]) by four aqua ligands in the equatorial sites and two 1,3-dimethyl-2,6-dioxo-3,7-di­hydro-1H-purin-9-ide ligands, through imidazole ring N atoms [N1 and N1(−x + 1, −y, −z + 1)], in the axial sites. The symmetry-unique purine ring system is essentially planar, with a maximum deviation of 0.030 (2) Å for N3 and the bonded methyl C atoms C4 and C5 deviate from this mean plane by −0.118 (3) and 0.136 (2) Å, respectively.

Table 1
Selected geometric parameters (Å, °)

Mg1—O3i 2.0672 (17) Mg1—N1i 2.2255 (19)
Mg1—O4i 2.081 (2)    
       
O3i—Mg1—O3 180.00 (3) O4—Mg1—N1i 91.31 (6)
O3—Mg1—O4i 87.98 (7) O3—Mg1—N1 90.06 (6)
O3—Mg1—O4 92.02 (7) O4—Mg1—N1 88.69 (6)
O4i—Mg1—O4 180.0 N1i—Mg1—N1 180.0
O3—Mg1—N1i 89.94 (6)    
Symmetry code: (i) -x+1, -y, -z+1.
[Figure 1]
Figure 1
The mol­ecular structure of the title complex, shown with 30% probability displacement ellipsoids [symmetry code: (A) x, −y, −z + 1).

3. Supra­molecular features

In the crystal, the coordinating water mol­ecules are involved in various hydrogen-bonding inter­actions (Table 2[link]). A [R_{4}^{2}](8) graph-set motif (Bernstein et al., 1995[Bernstein, J., Davis, R. E., Shimoni, L. & Chang, N.-L. (1995). Angew. Chem. Int. Ed. Engl. 34, 1555-1573.]) is formed through [O4⋯O1iii = 2.829 (3) Å and O4⋯O1iv = 2.780 (2) Å; symmetry codes: (iii) −x, −y, −z; (iv) x, y, z + 1] between a coordinating water mol­ecule and a carbonyl group of a symmetry-related theophylline group. The mononuclear units are connected into a layer parallel to (010) (Fig. 2[link]), which is further connected into a three-dimensional structure (Fig. 3[link]) by hydrogen-bonding inter­actions between coordin­ating water mol­ecules and symmetry-related imidazole groups [O3⋯N2ii = 2.809 (3) Å; symmetry code: (ii) x, −y + [{1\over 2}], z + [{1\over 2}]].

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A D⋯A D—H⋯A
O3—H3A⋯N2ii 0.88 (1) 1.97 (1) 2.809 (3) 160 (3)
O3—H3B⋯O2i 0.87 (1) 1.80 (1) 2.668 (2) 173 (3)
O4—H4E⋯O1iii 0.87 (1) 1.93 (1) 2.780 (2) 168 (3)
O4—H4D⋯O1iv 0.87 (1) 1.96 (1) 2.829 (3) 178 (3)
Symmetry codes: (i) -x+1, -y, -z+1; (ii) [x, -y+{\script{1\over 2}}, z+{\script{1\over 2}}]; (iii) -x, -y, -z; (iv) x, y, z+1.
[Figure 2]
Figure 2
Part of the crystal structure, showing hydrogen bonds in two dimensions (dashed lines).
[Figure 3]
Figure 3
Part of the crystal structure, showing the overall three-dimensional hydrogen-bonded structure (dashed lines).

4. Database survey

A search of the Cambridge Structural Database (Version 5.36, November 2014; Groom & Allen, 2014[Groom, C. R. & Allen, F. H. (2014). Angew. Chem. Int. Ed. 53, 662-671.]) revealed 16 metal complexes of theophylline, including ternary, polynuclear complexes and coordination polymers but only five are mononuclear complexes. The most closely related compound to the title complex, in terms of the ligand types is tri­aqua­bis­(theophylline)copper(II) dihydrate (WEZYIJ; Begum & Manohar, 1994[Begum, N. S. & Manohar, H. (1994). Polyhedron, 13, 307-312.]). The title compound is the first crystal structure reported to date of a complex of theophylline with an alkaline-earth metal.

5. Synthesis and crystallization

Theophylline (180 mg, 1 mmol) was dissolved in water (20 ml). An aqueous solution (15 ml) of NaOH (40 mg, 1 mmol) was added slowly. MgCl2·6H2O (102 mg, 0.5 mmol) in water (15 ml) was then added. The resulting solution was kept in air and, after several days, colourless block-shaped crystals were obtained.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. H atoms bonded to C atoms were positioned geometrically (C—H = 0.95–0.98 Å) with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C). H atoms bonded to O atoms were located in difference Fourier maps and were refined with a distance restraint of O—H = 0.87 (1) Å. The isotropic displacement parameters were refined freely.

Table 3
Experimental details

Crystal data
Chemical formula [Mg(C7H7N4O2)2(H2O)4]
Mr 454.71
Crystal system, space group Monoclinic, P21/c
Temperature (K) 295
a, b, c (Å) 7.694 (4), 13.399 (7), 9.739 (5)
β (°) 105.169 (9)
V (Å3) 969.0 (9)
Z 2
Radiation type Mo Kα
μ (mm−1) 0.16
Crystal size (mm) 0.2 × 0.2 × 0.2
 
Data collection
Diffractometer Rigaku CCD
Absorption correction Multi-scan (CrystalClear; Rigaku, 2000[Rigaku (2000). CrystalClear. Rigaku Corporation, Tokyo, Japan.])
Tmin, Tmax 0.949, 1.000
No. of measured, independent and observed [I > 2σ(I)] reflections 7442, 2153, 1738
Rint 0.032
(sin θ/λ)max (Å−1) 0.650
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.123, 1.09
No. of reflections 2153
No. of parameters 160
No. of restraints 4
H-atom treatment H atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3) 0.29, −0.25
Computer programs: CrystalClear (Rigaku, 2000[Rigaku (2000). CrystalClear. Rigaku Corporation, Tokyo, Japan.]), SHELXS97 and SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]) and X-SEED (Barbour, 2001[Barbour, L. J. (2001). J. Supramol. Chem. 1, 189-191.]).

Supporting information

CCDC reference: 1050901

Crystal structure: contains datablocks I, LOU. DOI: 10.1107/S2056989015003758/lh5752sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S2056989015003758/lh5752Isup2.hkl

checkCIF report


Chemical context top

Co-crystallization represents a crystal engineering approach for modifying properties of active pharmaceutical ingredients (APIs) (Sun, 2013). Metal coordination is an alternative strategy without changing chemical structures of APIs (Ma & Moulton, 2007). Theophylline is a methylxanthine drug in the treatment of asthma and chronic obstructive pulmonary disease (Barnes, 2003). In this paper, we reacted theophylline with the MgII ion in a basic solution to give rise to a tetra­aqua mononuclear MgII complex, (I).

Structural commentary top

The molecular structure of (I) is shown in Fig. 1. The complex lies across an inversion centre and the the MgII atom is coordinated in a slightly distorted o­cta­hedral environment by four aqua ligands in the equatorial sites and two 1,3-di­methyl-2,6-dioxo-3,7-di­hydro-1H-purin-9-ide ligands, through imidazole ring N atoms [N1 and N1(-x + 1, -y, -z + 1)], in the axial sites. The symmetry-unique purine ring system is essentially planar, with a maximum deviation of 0.030 (2) Å for N3 and the bonded methyl C atoms C4 and C5 deviate from this mean plane by -0.118 (3) and 0.136 (2) Å, respectively.

Supra­molecular features top

In the crystal, the coordinating water molecules are involved in various hydrogen-bonding inter­actions. A synthon with graph-set motif R42(8) (Bernstein et al., 1995) is formed through [O4···O1iii = 2.829 (3) Å and O4···O1iv = 2.780 (2) Å; symmetry codes: (iii) -x, -y, -z; (iv) x, y, z + 1] between a coordinating water molecule and a carbonyl group of a symmetry-related theophylline group. The mononuclear units are connected into a layer parallel to (???) (Fig. 2), which is further connected into a three-dimensional structure (Fig. 3) by hydrogen-bonding inter­actions between coordinating water molecules and symmetry-related imidazole groups [O3···N2ii = 2.809 (3) Å; symmetry code: (ii) x, -y+1/2, z+1/2].

Database survey top

A search of the Cambridge Structural Database (Version 5.36, November 2014; Groom & Allen, 2014) revealed 16 metal complexes of theophylline including ternary, polynuclear complexes and coordination polymers but only five are mononuclear complexes. The most closely related compound to the title complex, in terms of the ligand types is tri­aqua­bis­(theophylline)copper(II) dihydrate (WEZYIJ; Begum & Manohar, 1994). The title compound is the first crystal structure reported to date of a complex of theophylline with an alkaline-earth metal.

Synthesis and crystallization top

Theophylline (180 mg, 1 mmol) was dissolved in water (20 ml). An aqueous solution (15 ml) of NaOH (40 mg, 1 mmol) was added slowly. MgCl2·6H2O (102 mg, 0.5 mmol) in water (15 ml) was then added. The resulting solution was kept in air and, after several days, colourless block-shaped crystals were obtained.

Refinement top

H atoms bonded to C atoms were positioned geometrically (C—H = 0.95–0.98 Å) with Uiso(H) = 1.2Ueq(C) or 1.5Ueq(C). H atoms bonded to O atoms were located in difference Fourier maps and were refined with a distance restraint of O—H = 0.87 (1) Å. The isotropic displacement parameters were refined freely.

Related literature top

For related literature, see: Barnes (2003); Ma & Moulton (2007); Sun (2013); Bernstein et al. (1995); Groom et al. (2014); Begum & Manohar (1994).

Computing details top

Data collection: CrystalClear (Rigaku, 2000); cell refinement: CrystalClear (Rigaku, 2000); data reduction: CrystalClear (Rigaku, 2000); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: X-SEED (Barbour, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. The molecular structure of the title complex, shown with 30% probability displacement ellipsoids [symmetry code: (A) x, -y, -z + 1).
[Figure 2] Fig. 2. Part of the crystal structure, showing hydrogen bonds in two dimensions (dashed lines).
[Figure 3] Fig. 3. Part of the crystal structure, showing the overall three-dimensional hydrogen-bonded structure (dashed lines).
tetraaquabis(1,3-dimethyl-2,6-dioxo-3,7-dihydro-1H-purin-9-ido)magnesium(II) top
Crystal data top
[Mg(C7H7N4O2)2(H2O)4]F(000) = 476
Mr = 454.71Dx = 1.558 Mg m−3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 2170 reflections
a = 7.694 (4) Åθ = 2.7–27.5°
b = 13.399 (7) ŵ = 0.16 mm−1
c = 9.739 (5) ÅT = 295 K
β = 105.169 (9)°Prism, colorless
V = 969.0 (9) Å30.2 × 0.2 × 0.2 mm
Z = 2
Data collection top
Rigaku CCD
diffractometer		2153 independent reflections
Radiation source: fine-focus sealed tube1738 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.032
Detector resolution: 14.6306 pixels mm-1θmax = 27.5°, θmin = 2.7°
CCD_Profile_fitting scansh = −8→9
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)		k = −17→17
Tmin = 0.949, Tmax = 1.000l = −11→12
7442 measured 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)] = 0.049Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.123H atoms treated by a mixture of independent and constrained refinement
S = 1.09 w = 1/[σ2(Fo2) + (0.0542P)2 + 0.4099P]
where P = (Fo2 + 2Fc2)/3
2153 reflections(Δ/σ)max < 0.001
160 parametersΔρmax = 0.29 e Å−3
4 restraintsΔρmin = −0.25 e Å−3
Crystal data top
[Mg(C7H7N4O2)2(H2O)4]V = 969.0 (9) Å3
Mr = 454.71Z = 2
Monoclinic, P21/cMo Kα radiation
a = 7.694 (4) ŵ = 0.16 mm−1
b = 13.399 (7) ÅT = 295 K
c = 9.739 (5) Å0.2 × 0.2 × 0.2 mm
β = 105.169 (9)°
Data collection top
Rigaku CCD
diffractometer		2153 independent reflections
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2000)		1738 reflections with I > 2σ(I)
Tmin = 0.949, Tmax = 1.000Rint = 0.032
7442 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0494 restraints
wR(F2) = 0.123H atoms treated by a mixture of independent and constrained refinement
S = 1.09Δρmax = 0.29 e Å−3
2153 reflectionsΔρmin = −0.25 e Å−3
160 parameters
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
Mg10.50000.00000.50000.0220 (2)
O10.0856 (2)−0.02565 (12)−0.27579 (14)0.0366 (4)
O20.2118 (2)−0.14692 (11)0.17770 (15)0.0396 (4)
O30.5654 (2)0.14587 (11)0.56135 (16)0.0361 (4)
O40.2306 (2)0.02272 (14)0.49391 (16)0.0419 (4)
N10.4375 (2)0.04557 (11)0.27257 (16)0.0253 (4)
N20.4425 (2)0.16133 (12)0.09955 (17)0.0295 (4)
N30.2518 (2)0.07368 (12)−0.10112 (17)0.0277 (4)
N40.1533 (2)−0.08355 (12)−0.04781 (17)0.0260 (4)
C10.4967 (3)0.13335 (14)0.2386 (2)0.0285 (4)
H10.57330.17450.30830.034*
C20.3344 (2)0.01127 (14)0.14086 (19)0.0231 (4)
C30.3417 (3)0.08329 (14)0.0411 (2)0.0241 (4)
C40.2540 (4)0.15494 (17)−0.2003 (2)0.0426 (6)
H4A0.36230.1497−0.23500.064*
H4B0.25430.2190−0.15170.064*
H4C0.14680.1507−0.28090.064*
C50.0602 (3)−0.17694 (16)−0.1029 (2)0.0379 (5)
H5A−0.0695−0.1645−0.13670.057*
H5B0.0827−0.2270−0.02690.057*
H5C0.1054−0.2016−0.18190.057*
C60.1602 (2)−0.01192 (15)−0.1483 (2)0.0263 (4)
C70.2344 (3)−0.07757 (14)0.1001 (2)0.0256 (4)
H3A0.505 (3)0.2015 (13)0.557 (3)0.058 (8)*
H3B0.644 (3)0.149 (2)0.6439 (17)0.059 (9)*
H4D0.188 (4)0.007 (2)0.566 (2)0.072 (10)*
H4E0.142 (3)0.023 (2)0.4175 (19)0.055 (8)*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg10.0247 (5)0.0223 (4)0.0169 (5)0.0003 (3)0.0018 (3)0.0002 (3)
O10.0312 (8)0.0563 (10)0.0181 (7)−0.0009 (7)−0.0013 (6)−0.0023 (6)
O20.0501 (9)0.0329 (8)0.0287 (8)−0.0141 (7)−0.0021 (7)0.0066 (6)
O30.0495 (10)0.0243 (7)0.0278 (8)0.0015 (7)−0.0020 (7)−0.0018 (6)
O40.0278 (8)0.0722 (12)0.0239 (9)0.0027 (8)0.0034 (7)0.0008 (8)
N10.0292 (9)0.0234 (8)0.0207 (8)−0.0013 (6)0.0022 (7)−0.0005 (6)
N20.0375 (9)0.0255 (8)0.0238 (9)−0.0042 (7)0.0052 (7)0.0021 (6)
N30.0311 (9)0.0309 (9)0.0189 (8)0.0003 (7)0.0026 (7)0.0055 (6)
N40.0252 (8)0.0274 (8)0.0225 (8)−0.0018 (6)0.0010 (7)−0.0027 (6)
C10.0323 (10)0.0253 (10)0.0257 (10)−0.0041 (8)0.0037 (8)−0.0012 (8)
C20.0242 (9)0.0244 (9)0.0193 (9)0.0017 (7)0.0035 (7)0.0005 (7)
C30.0248 (9)0.0253 (9)0.0211 (9)0.0040 (7)0.0042 (7)0.0007 (7)
C40.0566 (15)0.0412 (13)0.0274 (12)0.0027 (11)0.0064 (10)0.0114 (9)
C50.0399 (12)0.0357 (11)0.0332 (12)−0.0078 (9)0.0011 (10)−0.0100 (9)
C60.0202 (9)0.0367 (11)0.0205 (10)0.0047 (8)0.0029 (7)−0.0006 (8)
C70.0257 (10)0.0274 (9)0.0223 (10)0.0003 (7)0.0039 (8)0.0000 (7)
Geometric parameters (Å, º) top
Mg1—O3i2.0672 (17)N3—C61.361 (3)
Mg1—O32.0672 (17)N3—C31.383 (2)
Mg1—O4i2.081 (2)N3—C41.459 (3)
Mg1—O42.081 (2)N4—C61.382 (3)
Mg1—N1i2.2255 (19)N4—C71.414 (3)
Mg1—N12.2255 (19)N4—C51.472 (3)
O1—C61.238 (2)C1—H10.9500
O2—C71.238 (2)C2—C31.381 (3)
O3—H3A0.875 (10)C2—C71.416 (3)
O3—H3B0.872 (10)C4—H4A0.9800
O4—H4D0.873 (10)C4—H4B0.9800
O4—H4E0.867 (10)C4—H4C0.9800
N1—C11.334 (3)C5—H5A0.9800
N1—C21.398 (2)C5—H5B0.9800
N2—C31.337 (2)C5—H5C0.9800
N2—C11.361 (3)
O3i—Mg1—O3180.00 (3)C6—N4—C5115.94 (16)
O3i—Mg1—O4i92.02 (7)C7—N4—C5117.55 (16)
O3—Mg1—O4i87.98 (7)N1—C1—N2116.97 (17)
O3i—Mg1—O487.98 (7)N1—C1—H1121.5
O3—Mg1—O492.02 (7)N2—C1—H1121.5
O4i—Mg1—O4180.0C3—C2—N1107.34 (17)
O3i—Mg1—N1i90.06 (6)C3—C2—C7120.60 (17)
O3—Mg1—N1i89.94 (6)N1—C2—C7132.06 (17)
O4i—Mg1—N1i88.69 (6)N2—C3—C2111.89 (17)
O4—Mg1—N1i91.31 (6)N2—C3—N3125.57 (17)
O3i—Mg1—N189.94 (6)C2—C3—N3122.53 (17)
O3—Mg1—N190.06 (6)N3—C4—H4A109.5
O4i—Mg1—N191.31 (6)N3—C4—H4B109.5
O4—Mg1—N188.69 (6)H4A—C4—H4B109.5
N1i—Mg1—N1180.0N3—C4—H4C109.5
Mg1—O3—H3A135.0 (19)H4A—C4—H4C109.5
Mg1—O3—H3B111.8 (19)H4B—C4—H4C109.5
H3A—O3—H3B103 (3)N4—C5—H5A109.5
Mg1—O4—H4D122 (2)N4—C5—H5B109.5
Mg1—O4—H4E125.3 (19)H5A—C5—H5B109.5
H4D—O4—H4E108 (3)N4—C5—H5C109.5
C1—N1—C2102.20 (16)H5A—C5—H5C109.5
C1—N1—Mg1119.32 (12)H5B—C5—H5C109.5
C2—N1—Mg1138.26 (13)O1—C6—N3121.81 (19)
C3—N2—C1101.59 (16)O1—C6—N4120.91 (19)
C6—N3—C3119.72 (16)N3—C6—N4117.28 (17)
C6—N3—C4120.00 (17)O2—C7—N4118.96 (17)
C3—N3—C4120.28 (17)O2—C7—C2127.74 (18)
C6—N4—C7126.42 (16)N4—C7—C2113.31 (17)
Symmetry code: (i) −x+1, −y, −z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···N2ii0.88 (1)1.97 (1)2.809 (3)160 (3)
O3—H3B···O2i0.87 (1)1.80 (1)2.668 (2)173 (3)
O4—H4E···O1iii0.87 (1)1.93 (1)2.780 (2)168 (3)
O4—H4D···O1iv0.87 (1)1.96 (1)2.829 (3)178 (3)
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z+1/2; (iii) −x, −y, −z; (iv) x, y, z+1.
Selected geometric parameters (Å, º) top
Mg1—O3i2.0672 (17)Mg1—N1i2.2255 (19)
Mg1—O4i2.081 (2)
O3i—Mg1—O3180.00 (3)O4—Mg1—N1i91.31 (6)
O3—Mg1—O4i87.98 (7)O3—Mg1—N190.06 (6)
O3—Mg1—O492.02 (7)O4—Mg1—N188.69 (6)
O4i—Mg1—O4180.0N1i—Mg1—N1180.0
O3—Mg1—N1i89.94 (6)
Symmetry code: (i) −x+1, −y, −z+1.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O3—H3A···N2ii0.875 (10)1.970 (14)2.809 (3)160 (3)
O3—H3B···O2i0.872 (10)1.800 (11)2.668 (2)173 (3)
O4—H4E···O1iii0.867 (10)1.926 (12)2.780 (2)168 (3)
O4—H4D···O1iv0.873 (10)1.956 (11)2.829 (3)178 (3)
Symmetry codes: (i) −x+1, −y, −z+1; (ii) x, −y+1/2, z+1/2; (iii) −x, −y, −z; (iv) x, y, z+1.

Experimental details

Crystal data
Chemical formula[Mg(C7H7N4O2)2(H2O)4]
Mr454.71
Crystal system, space groupMonoclinic, P21/c
Temperature (K)295
a, b, c (Å)7.694 (4), 13.399 (7), 9.739 (5)
β (°) 105.169 (9)
V (Å3)969.0 (9)
Z2
Radiation typeMo Kα
µ (mm−1)0.16
Crystal size (mm)0.2 × 0.2 × 0.2
Data collection
DiffractometerRigaku CCD
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2000)
Tmin, Tmax0.949, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections		7442, 2153, 1738
Rint0.032
(sin θ/λ)max (Å−1)0.650
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.049, 0.123, 1.09
No. of reflections2153
No. of parameters160
No. of restraints4
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å−3)0.29, −0.25

Computer programs: CrystalClear (Rigaku, 2000), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), X-SEED (Barbour, 2001).

 

Acknowledgements

The authors are grateful for grants from the Research Project for Young and Middle-aged Faculty of Fujian Province (JA14250) and the Undergraduate Innovative Research Program of Minjiang University (201310395059).

References

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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

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ISSN: 2056-9890
Volume 71| Part 3| March 2015| Pages 321-323
doi:10.1107/S2056989015003758
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