Tetra­aqua­bis[(1-ammonio-1-phosphono­ethyl)phospho­nato]zinc(II) tetra­hydrate

Abstract

The title compound, [Zn(C₂H₈NO₆P₂)₂(H₂O)₄]·4H₂O, was synthesized by the reaction of ZnCl₂ with 1-amino­ethane-1,1-diyldiphospho­nic acid in aqueous solution. The asymmetric unit contains one-half of the complex and two water mol­ecules of solvation. The Zn atom occupies a special position on an inversion centre. This results in a slightly distorted octa­hedral coordination environment, which consists of the O atoms from two phospho­nic acids and four water mol­ecules. The crystal structure displays N—H⋯O and O—H⋯O hydrogen bonding, which creates a three-dimensional network.

Related literature

Diphospho­nic acids are efficient drugs for the prevention of calcification and the inhibition of bone resorption, see: Matczak-Jon & Videnova-Adrabinska (2005 ▶). Diphospho­nic acids and their metal complexes are used in the treatment of Pagets disease, osteoporosis and tumoral osteolysis, see: Szabo et al. (2002 ▶). For related structures, see: Li et al. (2006 ▶, 2007 ▶); Lin et al. (2007 ▶).

Experimental

Crystal data

• [Zn(C₂H₈NO₆P₂)₂(H₂O)₄]·4H₂O

• M _r = 617.57

• Triclinic,

• a = 5.6712 (4) Å

• b = 9.3279 (6) Å

• c = 10.7009 (7) Å

• α = 96.440 (3)°

• β = 90.788 (3)°

• γ = 102.080 (3)°

• V = 549.65 (6) ų

• Z = 1

• Mo Kα radiation

• μ = 1.50 mm⁻¹

• T = 173 K

• 0.36 × 0.10 × 0.04 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: numerical (SADABS; Bruker, 2005 ▶) T _min = 0.612, T _max = 0.945

• 8897 measured reflections

• 2244 independent reflections

• 1747 reflections with I > 2σ(I)

• R _int = 0.058

Refinement

• R[F ² > 2σ(F ²)] = 0.037

• wR(F ²) = 0.081

• S = 1.00

• 2244 reflections

• 182 parameters

• 1 restraint

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.39 e Å⁻³

• Δρ_min = −0.48 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); 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: publCIF (Westrip, 2009 ▶).

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
N1—H1A⋯O6i	0.93 (4)	1.96 (4)	2.796 (4)	150 (3)
N1—H1B⋯O10	0.85 (4)	1.99 (4)	2.827 (4)	168 (3)
N1—H1C⋯O3i	0.90 (4)	2.01 (4)	2.851 (3)	153 (3)
O2—H2O⋯O3ii	0.78 (3)	1.76 (3)	2.536 (3)	172 (4)
O5—H5O⋯O6iii	0.793 (18)	1.726 (19)	2.519 (3)	177 (4)
O7—H71⋯O8iv	0.84 (4)	2.05 (4)	2.826 (3)	155 (3)
O7—H72⋯O10	0.76 (4)	2.00 (4)	2.748 (3)	168 (4)
O8—H81⋯O2	0.82 (4)	1.97 (4)	2.772 (3)	163 (3)
O8—H82⋯O9	0.86 (4)	1.79 (4)	2.646 (3)	174 (3)
O9—H91⋯O5v	0.87 (4)	1.94 (4)	2.810 (3)	172 (3)
O9—H92⋯O4vi	0.83 (4)	1.91 (4)	2.715 (3)	165 (4)
O10—H101⋯O4vii	0.85 (4)	1.90 (4)	2.744 (3)	175 (3)
O10—H102⋯O9iv	0.80 (4)	1.96 (4)	2.741 (3)	167 (4)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) .

supplementary crystallographic information

Comment

Organic diphosphonic acids are potentially very powerful chelating agents used in metal extractions and are tested by the pharmaceutical industry for use as efficient drugs preventing calcification and inhibiting bone resorption (Matczak-Jon et al., 2005). Diphosphonic acids and their metal complexes are used in the treatment of Pagets disease, osteoporosis and tumoral osteolysis (Szabo et al., 2002). The asymmetric unit of title compound contains one-half of the formula unit (Fig.1); Zn atom occupy special position at the inversion centre and creates a slightly distorted octahedral coordination environment, which consist of two phosphonic and four aqueous oxygen atoms. The coordinated diphosphonic acids residue exist as zwitterions with positive charge on NH₃ group and negative on the oxygen atom of the non-coordinated phosphonic group. The crystal structure displays N—H···O and O—H···O hydrogen bonding, which creates a three-dimensional network (Table 1, Fig.2).

Experimental

10 ml of the 0.01 M ZnCl₂ aqueous solution was added to the 10 ml of 0.02 M water solution of 1-aminoethane-1,1-diyldiphosphonic acid. Colorless crystals of title compound were obtained after 2 weeks of slow evaporation of the resulted solution.

Refinement

H atoms bonded to N and O were located in a difference map and were freely refined with U_iso(H) = 1.2 U_eq of the carrier atom. Other H atoms which bonded to C were positioned geometrically and refined using a riding model with C—H = 0.98 Å for CH₃ [U_iso(H) = 1.5Ueq(C)].

Figures

Fig. 1.

The title compound showing 50% probability displacement ellipsoids for the non-hydrogen atoms [Symmetry code: (i) -x, 1 - y, 1 - z].

Fig. 2.

Crystal packing of title compound, projection along a axis. Dashed lines indicate hydrogen bonds.

Crystal data

[Zn(C2H8NO6P2)2(H2O)4]·4H2O	Z = 1
Mr = 617.57	F(000) = 320
Triclinic, P1	Dx = 1.866 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 5.6712 (4) Å	Cell parameters from 2105 reflections
b = 9.3279 (6) Å	θ = 2.3–25.9°
c = 10.7009 (7) Å	µ = 1.50 mm−1
α = 96.440 (3)°	T = 173 K
β = 90.788 (3)°	Block, colourless
γ = 102.080 (3)°	0.36 × 0.10 × 0.04 mm
V = 549.65 (6) Å3

Data collection

Bruker APEXII CCD diffractometer	2244 independent reflections
Radiation source: fine-focus sealed tube	1747 reflections with I > 2σ(I)
graphite	Rint = 0.058
Detector resolution: 8.26 pixels mm-1	θmax = 26.4°, θmin = 2.3°
φ and ω scans	h = −7→7
Absorption correction: numerical (SADABS; Bruker, 2005)	k = −11→10
Tmin = 0.612, Tmax = 0.945	l = −13→13
8897 measured reflections

Refinement

Refinement on F2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.037	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.081	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ2(Fo2) + (0.0395P)2] where P = (Fo2 + 2Fc2)/3
2244 reflections	(Δ/σ)max < 0.001
182 parameters	Δρmax = 0.39 e Å−3
1 restraint	Δρmin = −0.47 e Å−3

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
Zn1	0.0000	0.5000	0.5000	0.01171 (16)
P1	0.02405 (14)	0.80873 (8)	0.37915 (7)	0.01033 (19)
P2	−0.00669 (14)	0.81048 (9)	0.09143 (7)	0.0116 (2)
C1	0.1808 (5)	0.8672 (3)	0.2381 (3)	0.0109 (6)
C2	0.2791 (6)	1.0348 (3)	0.2544 (3)	0.0176 (7)
H2A	0.3983	1.0614	0.3248	0.026*
H2B	0.1461	1.0855	0.2716	0.026*
H2C	0.3557	1.0644	0.1770	0.026*
N1	0.3905 (5)	0.7921 (3)	0.2240 (3)	0.0133 (6)
H1A	0.483 (6)	0.830 (4)	0.160 (3)	0.020*
H1B	0.349 (6)	0.699 (4)	0.208 (3)	0.020*
H1C	0.485 (6)	0.807 (4)	0.295 (3)	0.020*
O1	−0.0090 (4)	0.6449 (2)	0.37040 (19)	0.0135 (5)
O2	0.2165 (4)	0.8783 (2)	0.4886 (2)	0.0143 (5)
H2O	0.206 (6)	0.956 (4)	0.519 (3)	0.017*
O3	−0.1966 (4)	0.8741 (2)	0.39210 (19)	0.0139 (5)
O4	−0.0857 (4)	0.6470 (2)	0.0759 (2)	0.0181 (5)
O5	0.1793 (4)	0.8548 (2)	−0.0123 (2)	0.0148 (5)
H5O	0.182 (6)	0.931 (3)	−0.039 (3)	0.018*
O6	−0.1990 (4)	0.8997 (2)	0.0930 (2)	0.0156 (5)
O7	0.1908 (4)	0.3844 (3)	0.3764 (2)	0.0183 (5)
H71	0.319 (7)	0.371 (4)	0.408 (3)	0.022*
H72	0.204 (7)	0.413 (4)	0.312 (4)	0.022*
O8	0.3234 (4)	0.6366 (3)	0.5883 (2)	0.0152 (5)
H81	0.311 (6)	0.719 (4)	0.571 (3)	0.018*
H82	0.300 (6)	0.633 (4)	0.667 (4)	0.018*
O9	0.2666 (4)	0.6106 (3)	0.8304 (2)	0.0181 (5)
H91	0.228 (6)	0.681 (4)	0.882 (3)	0.022*
H92	0.189 (6)	0.532 (4)	0.852 (3)	0.022*
O10	0.3107 (4)	0.4849 (3)	0.1490 (2)	0.0187 (5)
H101	0.236 (6)	0.448 (4)	0.079 (4)	0.022*
H102	0.437 (7)	0.460 (4)	0.143 (3)	0.022*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Zn1	0.0117 (3)	0.0109 (3)	0.0129 (3)	0.0029 (2)	0.0003 (2)	0.0021 (2)
P1	0.0105 (4)	0.0103 (4)	0.0105 (4)	0.0031 (3)	0.0003 (3)	0.0009 (3)
P2	0.0115 (4)	0.0125 (4)	0.0116 (4)	0.0031 (3)	−0.0009 (3)	0.0035 (3)
C1	0.0096 (15)	0.0088 (15)	0.0146 (16)	0.0030 (12)	0.0003 (12)	0.0007 (12)
C2	0.0208 (18)	0.0114 (16)	0.0183 (18)	−0.0021 (13)	0.0001 (14)	0.0017 (13)
N1	0.0105 (14)	0.0155 (15)	0.0134 (15)	0.0010 (12)	−0.0017 (11)	0.0032 (12)
O1	0.0179 (12)	0.0093 (11)	0.0133 (12)	0.0028 (9)	0.0007 (9)	0.0011 (8)
O2	0.0164 (12)	0.0141 (12)	0.0129 (12)	0.0067 (10)	−0.0032 (9)	−0.0032 (9)
O3	0.0118 (11)	0.0150 (12)	0.0154 (12)	0.0049 (9)	−0.0013 (9)	−0.0004 (9)
O4	0.0224 (13)	0.0143 (12)	0.0158 (12)	0.0001 (9)	−0.0047 (10)	0.0013 (9)
O5	0.0187 (12)	0.0118 (12)	0.0167 (12)	0.0061 (10)	0.0061 (9)	0.0080 (9)
O6	0.0113 (11)	0.0206 (12)	0.0178 (12)	0.0060 (9)	0.0024 (9)	0.0092 (9)
O7	0.0186 (13)	0.0225 (13)	0.0162 (13)	0.0090 (10)	−0.0004 (11)	0.0043 (10)
O8	0.0146 (12)	0.0139 (12)	0.0181 (13)	0.0034 (10)	−0.0017 (10)	0.0054 (10)
O9	0.0201 (13)	0.0148 (12)	0.0199 (13)	0.0042 (10)	0.0041 (10)	0.0025 (10)
O10	0.0152 (13)	0.0239 (13)	0.0176 (13)	0.0072 (11)	−0.0022 (10)	−0.0004 (10)

Geometric parameters (Å, °)

Zn1—O1	2.050 (2)	C2—H2A	0.9800
Zn1—O1i	2.050 (2)	C2—H2B	0.9800
Zn1—O7i	2.071 (2)	C2—H2C	0.9800
Zn1—O7	2.071 (2)	N1—H1A	0.93 (4)
Zn1—O8i	2.141 (2)	N1—H1B	0.85 (4)
Zn1—O8	2.141 (2)	N1—H1C	0.90 (4)
P1—O1	1.492 (2)	O2—H2O	0.78 (3)
P1—O3	1.504 (2)	O5—H5O	0.793 (18)
P1—O2	1.575 (2)	O7—H71	0.84 (4)
P1—C1	1.839 (3)	O7—H72	0.76 (4)
P2—O4	1.486 (2)	O8—H81	0.82 (4)
P2—O6	1.503 (2)	O8—H82	0.86 (4)
P2—O5	1.571 (2)	O9—H91	0.87 (4)
P2—C1	1.846 (3)	O9—H92	0.83 (4)
C1—N1	1.502 (4)	O10—H101	0.85 (4)
C1—C2	1.535 (4)	O10—H102	0.80 (4)
O1—Zn1—O1i	179.999 (1)	N1—C1—P1	107.2 (2)
O1—Zn1—O7i	90.77 (9)	C2—C1—P1	110.6 (2)
O1i—Zn1—O7i	89.23 (9)	N1—C1—P2	106.55 (19)
O1—Zn1—O7	89.23 (9)	C2—C1—P2	110.3 (2)
O1i—Zn1—O7	90.77 (9)	P1—C1—P2	113.58 (16)
O7i—Zn1—O7	180.00 (11)	C1—C2—H2A	109.5
O1—Zn1—O8i	88.74 (9)	C1—C2—H2B	109.5
O1i—Zn1—O8i	91.26 (9)	H2A—C2—H2B	109.5
O7i—Zn1—O8i	92.46 (9)	C1—C2—H2C	109.5
O7—Zn1—O8i	87.54 (9)	H2A—C2—H2C	109.5
O1—Zn1—O8	91.27 (9)	H2B—C2—H2C	109.5
O1i—Zn1—O8	88.73 (9)	C1—N1—H1A	108 (2)
O7i—Zn1—O8	87.54 (9)	C1—N1—H1B	114 (2)
O7—Zn1—O8	92.46 (9)	H1A—N1—H1B	110 (3)
O8i—Zn1—O8	180.0	C1—N1—H1C	113 (2)
O1—P1—O3	118.11 (12)	H1A—N1—H1C	108 (3)
O1—P1—O2	107.82 (12)	H1B—N1—H1C	104 (3)
O3—P1—O2	111.01 (12)	P1—O1—Zn1	133.80 (13)
O1—P1—C1	107.13 (13)	P1—O2—H2O	115 (3)
O3—P1—C1	108.84 (13)	P2—O5—H5O	118 (3)
O2—P1—C1	102.79 (13)	Zn1—O7—H71	113 (2)
O4—P2—O6	117.67 (13)	Zn1—O7—H72	114 (3)
O4—P2—O5	108.21 (12)	H71—O7—H72	114 (4)
O6—P2—O5	110.56 (12)	Zn1—O8—H81	101 (2)
O4—P2—C1	108.34 (13)	Zn1—O8—H82	103 (2)
O6—P2—C1	108.52 (13)	H81—O8—H82	108 (3)
O5—P2—C1	102.44 (13)	H91—O9—H92	106 (3)
N1—C1—C2	108.4 (3)	H101—O10—H102	103 (3)
O1—P1—C1—N1	−47.7 (2)	O6—P2—C1—C2	−54.5 (2)
O3—P1—C1—N1	−176.47 (18)	O5—P2—C1—C2	62.5 (2)
O2—P1—C1—N1	65.8 (2)	O4—P2—C1—P1	−58.45 (19)
O1—P1—C1—C2	−165.7 (2)	O6—P2—C1—P1	70.38 (18)
O3—P1—C1—C2	65.6 (2)	O5—P2—C1—P1	−172.68 (15)
O2—P1—C1—C2	−52.2 (2)	O3—P1—O1—Zn1	−92.94 (19)
O1—P1—C1—P2	69.67 (18)	O2—P1—O1—Zn1	33.8 (2)
O3—P1—C1—P2	−59.08 (18)	C1—P1—O1—Zn1	143.85 (17)
O2—P1—C1—P2	−176.85 (15)	O7i—Zn1—O1—P1	41.88 (18)
O4—P2—C1—N1	59.3 (2)	O7—Zn1—O1—P1	−138.12 (18)
O6—P2—C1—N1	−171.88 (19)	O8i—Zn1—O1—P1	134.32 (18)
O5—P2—C1—N1	−54.9 (2)	O8—Zn1—O1—P1	−45.68 (18)
O4—P2—C1—C2	176.7 (2)

Symmetry codes: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1A···O6ii	0.93 (4)	1.96 (4)	2.796 (4)	150 (3)
N1—H1B···O10	0.85 (4)	1.99 (4)	2.827 (4)	168 (3)
N1—H1C···O3ii	0.90 (4)	2.01 (4)	2.851 (3)	153 (3)
O2—H2O···O3iii	0.78 (3)	1.76 (3)	2.536 (3)	172 (4)
O5—H5O···O6iv	0.79 (2)	1.73 (2)	2.519 (3)	177 (4)
O7—H71···O8v	0.84 (4)	2.05 (4)	2.826 (3)	155 (3)
O7—H72···O10	0.76 (4)	2.00 (4)	2.748 (3)	168 (4)
O8—H81···O2	0.82 (4)	1.97 (4)	2.772 (3)	163 (3)
O8—H82···O9	0.86 (4)	1.79 (4)	2.646 (3)	174 (3)
O9—H91···O5vi	0.87 (4)	1.94 (4)	2.810 (3)	172 (3)
O9—H92···O4i	0.83 (4)	1.91 (4)	2.715 (3)	165 (4)
O10—H101···O4vii	0.85 (4)	1.90 (4)	2.744 (3)	175 (3)
O10—H102···O9v	0.80 (4)	1.96 (4)	2.741 (3)	167 (4)

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