Poly[diaqua­bis(μ-4-carb­oxy-2-propyl-1H-imidazole-5-carboxyl­ato-κ³ N ³,O ⁴:O ⁵)calcium(II)]

Abstract

In the title complex, [Ca(C₈H₉N₂O₄)₂(H₂O)₂]_n, the Ca^II atom is eight-coordinated in a distorted square-anti­prismatic environment. The water-coordinated Ca atom is N,O-chelated by the monocarboxyl­ate anion; the carboxyl –CO₂ portion engaged in chelation bears an acid hydrogen. The free –CO₂ portion engages in bonding to adjacent Ca atoms. The Ca^II centres are connected through the ligand, forming a layer structure; the layers are linked by hydrogen bonds into a three-dimensional network.

Related literature

For the potential uses and diverse structrual types of structures containing metals and N-heterocyclic carboxylic acids, see: Liang et al. (2002 ▶); Net et al. (1989 ▶); Nie et al. (2007 ▶).

Experimental

Crystal data

• [Ca(C₈H₉N₂O₄)₂(H₂O)₂]

• M _r = 470.46

• Monoclinic,

• a = 12.703 (3) Å

• b = 13.006 (3) Å

• c = 11.697 (2) Å

• β = 97.864 (2)°

• V = 1914.3 (7) ų

• Z = 4

• Mo Kα radiation

• μ = 0.40 mm⁻¹

• T = 273 K

• 0.32 × 0.24 × 0.20 mm

Data collection

• Bruker APEXII area-detector diffractometer

• Absorption correction: multi-scan (SADABS; Bruker, 2004 ▶) T _min = 0.884, T _max = 0.925

• 4830 measured reflections

• 1718 independent reflections

• 1504 reflections with I > 2σ(I)

• R _int = 0.040

Refinement

• R[F ² > 2σ(F ²)] = 0.034

• wR(F ²) = 0.099

• S = 1.02

• 1718 reflections

• 144 parameters

• 3 restraints

• H-atom parameters constrained

• Δρ_max = 0.29 e Å⁻³

• Δρ_min = −0.23 e Å⁻³

Data collection: APEX2 (Bruker, 2004 ▶); cell refinement: SAINT (Bruker, 2004 ▶); data reduction: SAINT; 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.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2⋯O1i	0.86	2.01	2.859 (2)	171
O1W—H2W⋯O1ii	0.83	2.31	3.088 (2)	156
O1W—H1W⋯O3iii	0.84	2.12	2.947 (2)	172

Symmetry codes: (i) ; (ii) ; (iii) .

supplementary crystallographic information

Comment

Recently, structures containing metals and N-heterocyclic carboxylic acids has attracted much attention, they can function as a multidentate ligand, exhibiting diverse structrual type and can be potentially used as functional materials (Nie et al., 2007; Liang et al.,2002; Net et al., 1989). In this paper, we report the synthesis and structure of a new Ca(II) complex obtained from 2-Propyl-1H- imidazole-4,5-dicarboxy with metal salts under hydrothermal conditions.

As illustrated in figure 1, the title complex molecule is eight-coordinated by two chelating rings [Ca—N=2.5998 (15)Å and Ca—O=2.605 (5) Å] and two carboxylate O atoms from two different 2-Propyl-1H-imidazole-4,5-dicarboxylate ligands and two water molecules, exhibiting a distorted square antiprismatic structure, the title Complex displays an extended two-dimensional layer structure constructed of quasi-squares, with four Ca atoms at the corners and 2-Propyl-1H-imidazole-4,5-dicarboxylate anions at each edge as linkers connecting two Ca atoms. the edge lengthes are equal, with a value of 9.0901 (16) Å. the angles of the rhombus are 88.650 (2)° and 91.350 (5)°(Fig. 2). Two dimensional layers are further linked by hydrogen bonds(Table 1), forming a three-dimensional network(Fig. 3)

Experimental

A mixture of Ca(II)chloride (0.5 mmol, 0.055 g) and 2-propyl-1H-imidazole-4,5-dicarboxylic acid(0.5 mmol, 0.99 g) in 10 ml of distilled water was sealed in an autoclave equipped with a Teflon liner (20 ml) and then heated at 433k for 3 days. Crystals of the title compound were obtained by slow evaporation of the solvent at room temperature.

Refinement

Carbon and nitrogen bound H atoms were placed at calculated positions and were treated as riding on the parent C or N atoms with C—H = 0.93 Å, N—H = 0.86 Å, and with U_iso(H) = 1.2 U_eq(C, N). The water H-atoms were located in a difference map, and were refined with a distance restraint of O—H = 0.84 Å; their U_iso values were refined.

Figures

Fig. 1.

The structure of the title compound, showing the atomic numbering scheme. Non-H atoms are shown with 30% probability displacement ellipsoids(H atoms are represented by arbitrary spheres). [Symmetry codes:[(A)1 - x,y,1.5 - z;(B)-1/2 + x,1/2 + y,z;(C)1.5 - x,1/2 + y,1.5 - z.]

Fig. 2.

A view of an extended two-dimensional layer structure of the title compound.

Fig. 3.

View the three-dimensional network.

Crystal data

[Ca(C8H9N2O4)2(H2O)2]	F(000) = 984
Mr = 470.46	Dx = 1.632 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 3600 reflections
a = 12.703 (3) Å	θ = 1.4–28°
b = 13.006 (3) Å	µ = 0.40 mm−1
c = 11.697 (2) Å	T = 273 K
β = 97.864 (2)°	Block, white
V = 1914.3 (7) Å3	0.32 × 0.24 × 0.20 mm
Z = 4

Data collection

Bruker APEXII area-detector diffractometer	1718 independent reflections
Radiation source: fine-focus sealed tube	1504 reflections with I > 2σ(I)
graphite	Rint = 0.040
φ and ω scan	θmax = 25.2°, θmin = 2.3°
Absorption correction: multi-scan (SADABS; Bruker, 2004)	h = −13→15
Tmin = 0.884, Tmax = 0.925	k = −14→15
4830 measured reflections	l = −14→13

Refinement

Refinement on F2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.034	H-atom parameters constrained
wR(F2) = 0.099	w = 1/[σ2(Fo2) + (0.0551P)2 + 1.470P] where P = (Fo2 + 2Fc2)/3
S = 1.01	(Δ/σ)max < 0.001
1718 reflections	Δρmax = 0.29 e Å−3
144 parameters	Δρmin = −0.23 e Å−3
3 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0076 (9)

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
Ca1	0.5000	0.07420 (4)	0.2500	0.0189 (2)
O1	0.33875 (11)	0.05035 (10)	0.36313 (12)	0.0262 (3)
O1W	0.55495 (11)	0.10622 (11)	0.45862 (12)	0.0319 (4)
H1W	0.5121	0.1347	0.4970	0.048*
H2W	0.5769	0.0519	0.4904	0.048*
O2	0.20033 (11)	0.11430 (10)	0.43530 (13)	0.0296 (4)
H1	0.1663	0.1680	0.4316	0.044*
O3	0.09452 (11)	0.27478 (11)	0.42169 (12)	0.0308 (4)
O4	0.09469 (12)	0.42512 (10)	0.33195 (13)	0.0352 (4)
N1	0.36595 (12)	0.22589 (11)	0.23987 (13)	0.0201 (4)
N2	0.26433 (12)	0.36382 (11)	0.21921 (13)	0.0225 (4)
H2	0.2403	0.4229	0.1951	0.027*
C1	0.28670 (14)	0.21777 (14)	0.30920 (15)	0.0192 (4)
C2	0.22299 (14)	0.30376 (14)	0.29747 (16)	0.0209 (4)
C3	0.34950 (14)	0.31557 (14)	0.18572 (16)	0.0215 (4)
C4	0.27622 (14)	0.12212 (14)	0.37333 (16)	0.0204 (4)
C5	0.40949 (15)	0.36092 (15)	0.09774 (17)	0.0255 (4)
H5A	0.4753	0.3231	0.0974	0.031*
H5B	0.4277	0.4315	0.1189	0.031*
C6	0.34718 (17)	0.35929 (17)	−0.02384 (18)	0.0334 (5)
H6A	0.3399	0.2888	−0.0508	0.040*
H6B	0.2764	0.3865	−0.0212	0.040*
C7	0.40144 (19)	0.42208 (18)	−0.1082 (2)	0.0382 (6)
H7A	0.4067	0.4924	−0.0832	0.057*
H7B	0.3606	0.4184	−0.1835	0.057*
H7C	0.4714	0.3952	−0.1113	0.057*
C8	0.13058 (15)	0.33836 (15)	0.35251 (16)	0.0240 (4)

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Ca1	0.0189 (3)	0.0157 (3)	0.0229 (3)	0.000	0.0052 (2)	0.000
O1	0.0267 (7)	0.0187 (7)	0.0336 (8)	0.0026 (6)	0.0051 (6)	0.0014 (6)
O1W	0.0345 (8)	0.0327 (8)	0.0299 (8)	0.0035 (6)	0.0095 (6)	0.0011 (6)
O2	0.0303 (8)	0.0228 (7)	0.0384 (8)	0.0041 (6)	0.0140 (7)	0.0073 (6)
O3	0.0295 (8)	0.0300 (8)	0.0360 (8)	0.0045 (6)	0.0155 (6)	0.0036 (6)
O4	0.0385 (9)	0.0295 (8)	0.0394 (9)	0.0182 (6)	0.0119 (7)	0.0052 (6)
N1	0.0188 (8)	0.0190 (8)	0.0231 (8)	0.0000 (6)	0.0049 (6)	0.0001 (6)
N2	0.0250 (8)	0.0157 (8)	0.0275 (9)	0.0045 (6)	0.0059 (7)	0.0042 (6)
C1	0.0185 (9)	0.0192 (9)	0.0198 (9)	−0.0003 (7)	0.0023 (7)	−0.0013 (7)
C2	0.0219 (9)	0.0200 (9)	0.0212 (9)	0.0015 (7)	0.0046 (8)	−0.0011 (7)
C3	0.0207 (9)	0.0201 (9)	0.0236 (10)	−0.0007 (7)	0.0027 (8)	−0.0004 (7)
C4	0.0203 (9)	0.0191 (9)	0.0215 (10)	−0.0007 (7)	0.0020 (7)	−0.0016 (7)
C5	0.0230 (10)	0.0255 (10)	0.0288 (11)	−0.0018 (8)	0.0062 (8)	0.0047 (8)
C6	0.0311 (11)	0.0350 (12)	0.0332 (12)	−0.0093 (9)	0.0012 (9)	0.0059 (9)
C7	0.0419 (13)	0.0429 (13)	0.0294 (12)	−0.0077 (10)	0.0037 (10)	0.0069 (9)
C8	0.0235 (10)	0.0266 (10)	0.0219 (10)	0.0022 (8)	0.0035 (8)	−0.0017 (8)

Geometric parameters (Å, °)

Ca1—O4i	2.4104 (14)	N1—C1	1.380 (2)
Ca1—O4ii	2.4104 (14)	N2—C3	1.354 (2)
Ca1—O1W	2.4798 (15)	N2—C2	1.362 (2)
Ca1—O1Wiii	2.4799 (15)	N2—H2	0.8600
Ca1—N1iii	2.5982 (15)	C1—C2	1.376 (3)
Ca1—N1	2.5982 (15)	C1—C4	1.468 (3)
Ca1—O1	2.6048 (14)	C2—C8	1.484 (3)
Ca1—O1iii	2.6049 (14)	C3—C5	1.484 (3)
O1—C4	1.242 (2)	C5—C6	1.530 (3)
O1W—H1W	0.8378	C5—H5A	0.9700
O1W—H2W	0.8287	C5—H5B	0.9700
O2—C4	1.287 (2)	C6—C7	1.517 (3)
O2—H1	0.8200	C6—H6A	0.9700
O3—C8	1.284 (2)	C6—H6B	0.9700
O4—C8	1.228 (2)	C7—H7A	0.9600
O4—Ca1iv	2.4102 (14)	C7—H7B	0.9600
N1—C3	1.330 (2)	C7—H7C	0.9600
O4i—Ca1—O4ii	72.89 (8)	C3—N2—C2	108.98 (15)
O4i—Ca1—O1W	125.76 (5)	C3—N2—H2	125.5
O4ii—Ca1—O1W	71.69 (5)	C2—N2—H2	125.5
O4i—Ca1—O1Wiii	71.69 (5)	C2—C1—N1	110.21 (16)
O4ii—Ca1—O1Wiii	125.76 (5)	C2—C1—C4	130.27 (17)
O1W—Ca1—O1Wiii	160.66 (7)	N1—C1—C4	119.30 (15)
O4i—Ca1—N1iii	156.52 (5)	N2—C2—C1	104.93 (16)
O4ii—Ca1—N1iii	107.72 (5)	N2—C2—C8	121.21 (16)
O1W—Ca1—N1iii	74.52 (5)	C1—C2—C8	133.83 (17)
O1Wiii—Ca1—N1iii	90.68 (5)	N1—C3—N2	110.39 (16)
O4i—Ca1—N1	107.72 (5)	N1—C3—C5	128.07 (17)
O4ii—Ca1—N1	156.53 (5)	N2—C3—C5	121.51 (17)
O1W—Ca1—N1	90.68 (5)	O1—C4—O2	122.20 (17)
O1Wiii—Ca1—N1	74.52 (5)	O1—C4—C1	118.94 (16)
N1iii—Ca1—N1	81.19 (7)	O2—C4—C1	118.82 (16)
O4i—Ca1—O1	73.86 (5)	C3—C5—C6	112.93 (16)
O4ii—Ca1—O1	94.96 (5)	C3—C5—H5A	109.0
O1W—Ca1—O1	69.83 (5)	C6—C5—H5A	109.0
O1Wiii—Ca1—O1	112.64 (5)	C3—C5—H5B	109.0
N1iii—Ca1—O1	128.56 (5)	C6—C5—H5B	109.0
N1—Ca1—O1	63.74 (4)	H5A—C5—H5B	107.8
O4i—Ca1—O1iii	94.96 (5)	C7—C6—C5	111.95 (17)
O4ii—Ca1—O1iii	73.85 (5)	C7—C6—H6A	109.2
O1W—Ca1—O1iii	112.64 (5)	C5—C6—H6A	109.2
O1Wiii—Ca1—O1iii	69.82 (5)	C7—C6—H6B	109.2
N1iii—Ca1—O1iii	63.74 (4)	C5—C6—H6B	109.2
N1—Ca1—O1iii	128.56 (5)	H6A—C6—H6B	107.9
O1—Ca1—O1iii	166.32 (6)	C6—C7—H7A	109.5
C4—O1—Ca1	121.13 (12)	C6—C7—H7B	109.5
Ca1—O1W—H1W	119.1	H7A—C7—H7B	109.5
Ca1—O1W—H2W	109.3	C6—C7—H7C	109.5
H1W—O1W—H2W	109.8	H7A—C7—H7C	109.5
C4—O2—H1	109.5	H7B—C7—H7C	109.5
C8—O4—Ca1iv	165.57 (15)	O4—C8—O3	124.05 (18)
C3—N1—C1	105.49 (14)	O4—C8—C2	119.22 (17)
C3—N1—Ca1	138.32 (12)	O3—C8—C2	116.72 (17)
C1—N1—Ca1	116.18 (11)

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

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O1v	0.86	2.01	2.859 (2)	171
O1W—H2W···O1vi	0.83	2.31	3.088 (2)	156
O1W—H1W···O3vii	0.84	2.12	2.947 (2)	172

Symmetry codes: (v) −x+1/2, y+1/2, −z+1/2; (vi) −x+1, −y, −z+1; (vii) −x+1/2, −y+1/2, −z+1.