2-Hydroxy­propane-1,3-diammonium bis­(phospho­nato)zincate(II) hemihydrate

In the title compound, (C₃H₁₂N₂O)[Zn(HPO₃)₂]·0.5H₂O, the inorganic macroanionic chain is built up from ZnO₄ tetra­hedra and HPO₃ pseudo-pyramids sharing vertices. The organic dication shows positional disorder of its central –OH group in a 0.614 (7):0.386 (7) ratio. The components inter­act by way of O—H...O and N—H...O hydrogen bonds. The Zn atom lies on a crystallographic twofold axis and one C atom, the disordered O atoms of the –OH groups and the water O atom lie on a crystallographic mirror plane.

Key indicators

• Single-crystal X-ray study
• T = 120 K
• Mean [sigma](C-C) = 0.003 Å
• Disorder in main residue
• R factor = 0.028
• wR factor = 0.064
• Data-to-parameter ratio = 15.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT213_ALERT_2_B Atom O4B     has ADP max/min Ratio .............       4.10 prola
PLAT416_ALERT_2_B Short Intra D-H..H-D       H4     ..  H4B     ..       1.86 Ang.

Alert level C
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 ............       0.25 Ratio
PLAT076_ALERT_1_C Occupancy       0.50 less than 1.0 for Sp.pos  .         O5
PLAT215_ALERT_3_C Disordered O5      has ADP max/min Ratio .......       3.30
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.54 Ratio
PLAT245_ALERT_2_C U(iso) H2B     Smaller than U(eq) O4B     by ...       0.04 AngSq
PLAT301_ALERT_3_C Main Residue  Disorder .........................       5.00 Perc.
PLAT313_ALERT_2_C Oxygen with three covalent bonds (rare) ........        O4A
PLAT313_ALERT_2_C Oxygen with three covalent bonds (rare) ........        O4B
PLAT416_ALERT_2_C Short Intra D-H..H-D       H3     ..  H4A     ..       1.95 Ang.
PLAT764_ALERT_4_C Overcomplete CIF Bond List Detected (Rep/Expd) .       1.18 Ratio

Alert level G
PLAT793_ALERT_1_G Check the Absolute Configuration of P1     = ...          S

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

   5 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   6 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The title compound, C₃H₁₂N₂O·Zn(HPO₃)₂·0.5H₂O, (I), (Fig. 1) complements the growing family of templated zincophosphite networks (e.g. Holtby et al., 2007).

The connectivity of the polyhedra in the inorganic zincophosphite component of (I) results in macroanionic chains of 4-rings propagating in [010]. The constituent ZnO₄ and HPO₃ units have normal geometrical paramters (Table 1), with the Zn atom lying on a crystallographic 2-fold axis. Each Zn atom therefore serves as a node for the chain with O1 and O2 serving as the linking atoms whereas P1—O3 is a terminal bond.

The complete [H₃NCH₂CHOHCH₂NH₃]²⁺ dication in (I) is generated by mirror symmetry, with C2 lying on the reflecting plane. The pendant –OH group attached to C2 is disordered over two positions, with both O atoms also occupying the reflection plane. A water molecule (site symmetry m) with a fractional site occupancy of 0.5 completes the structure of (I).

The unit-cell packing for (I) (Fig. 2) results in the [010] chains of stoichiometry [Zn(HPO₃)₂]^2- being crosslinked by the water molecule in the [001] direction, with linking O—H···O hydrogen bonds (Table 2) as the key structural feature. The organic cation occupies the space between the pseudo (100) layes and further consolidates the structure through O—H···O and also N—H···O hydrogen bonds.

The [H₃NCH₂CHOHCH₂NH₃]²⁺ cation has been used to template other inorganic networks including zinc phosphates (Chidambaram et al., 1999), tin phosphates (Vaidhyanathan & Natarajan, 1999) and iron oxalato-phosphates (Choudhury et al., 2000). It is notable that in most of these phases, the –OH group of the template shows similar positional disorder to that observed here.

Related literature

For background, see: Holtby et al. (2007). For other inorganic networks templated by the same cation, see: Chidambaram et al. (1999); Choudhury et al. (2000); Vaidhyanathan & Natarajan (1999).

S2. Experimental

Zinc oxide, phosphorus acid and 1,3-diamino-2-propanol were mixed in a 1:2:1:500 molar ratio with 20 ml H₂O and shaken. The mixture was placed in a sealted plastic bottle and heated to 353 K for 2 days. Upon cooling and filtration, colourless blocks of (I) were recovered.

S3. Refinement

The water O5 atom yielded an unreasonably large U_iso value when full fractional occupancy was assumed. Refining the occupancy for O5 led to a value near 1/2, which was fixed for the final cycles of refinement. Reducing the occupancy for O5 also lowered the R factors and led to a more plausible U_iso value, before anisotropic refinement was finally carrued out. The –OH group of the dication is disordered over two positions in a 0.614 (7):0.386 (7) ratio (sum constrained to unity).

Upon anisotropic refinement, O4a, O4b and O5 showed elongated displacement ellipsoids. Attempts to model this situation with split-atom sites or in lower symmetry space groups were not successful. On account of the resulting short H4···H4B distance of 1.86 Å, the positions of the H atoms of the –OH groups should be regarded as less certain. However, it is notable that both H4 and H4b are involved in hydrogen bonds to the same acceptor atom.

The water H atom was located in a difference map and refined as riding in its as-found relative position with U_iso(H) = 1.2U_eq(O). The other H atoms were placed in calculated positions (C—H = 0.99 Å, N—H = 0.91 Å, O—H = 0.90 Å) and refined as riding with U_iso(H) = 1.2U_eq(carrier). The –NH₃ group was allowed to rotate, but not to tip, to best fit the electron density.

Computing details

Data collection: COLLECT (Nonius BV, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997), and SORTAV (Blessing, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. View of the asymmetric unit of (I) expanded to show the complete organic dication and the Zn coordination sphere. Displacement ellipsoids are drawn at the 50% probability level and hydrogen atoms are drawn as spheres of arbitrary radius. Hydrogen bonds are shown as double dashed lines. Symmetry codes: (i) -x, 1 - y, -z; (ii) -x, y - 1/2, z; (iii) x, 1/2 - y, -z; (iv) x, y, 1/2 - z. Only one disorder component of the organic species is shown.

Fig. 2. Unit-cell packing for (I) viewed down [010]. ZnO4 tetrahedra sand, HPO3 tetrahedra green, C grey, H white, N blue, O red. The hydrogen bonds are shaded yellow.

2-Hydroxypropane-1,3-diammonium bis(phosphonato)zincate(II) hemihydrate

Crystal data

(C3H12N2O)[Zn(HPO3)2]·0.5H2O	F(000) = 668
Mr = 326.48	Dx = 1.877 Mg m^−3
Orthorhombic, Pbcm	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2c 2b	Cell parameters from 1544 reflections
a = 8.8554 (3) Å	θ = 2.9–27.5°
b = 7.8466 (3) Å	µ = 2.43 mm^−1
c = 16.6251 (5) Å	T = 120 K
V = 1155.19 (7) Å^3	Block, colourless
Z = 4	0.28 × 0.20 × 0.10 mm

Data collection

Nonius KappaCCD diffractometer	1370 independent reflections
Radiation source: fine-focus sealed tube	1271 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.031
ω and φ scans	θmax = 27.5°, θmin = 3.5°
Absorption correction: multi-scan (SADABS; Bruker, 2003)	h = −9→11
Tmin = 0.550, Tmax = 0.793	k = −10→8
10217 measured reflections	l = −21→19

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difmap and geom
R[F^2 > 2σ(F^2)] = 0.028	H-atom parameters constrained
wR(F^2) = 0.064	w = 1/[σ^2(Fo^2) + (0.0046P)^2 + 2.8213P] where P = (Fo^2 + 2Fc^2)/3
S = 1.12	(Δ/σ)max = 0.002
1370 reflections	Δρmax = 0.45 e Å^−3
87 parameters	Δρmin = −0.38 e Å^−3
0 restraints	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0029 (6)

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	Occ. (<1)
Zn1	0.04498 (4)	0.2500	0.0000	0.01367 (13)
P1	0.19574 (7)	0.55780 (8)	0.09909 (4)	0.01743 (16)
H1	0.1771	0.4733	0.1670	0.021*
O1	0.06921 (19)	0.6883 (2)	0.09460 (10)	0.0226 (4)
O2	0.18811 (18)	0.4268 (2)	0.03132 (10)	0.0207 (4)
O3	0.3492 (2)	0.6382 (3)	0.10293 (17)	0.0458 (7)
C1	0.6993 (3)	0.5624 (3)	0.17508 (14)	0.0230 (5)
H1A	0.6814	0.6869	0.1765	0.028*
H1B	0.8097	0.5431	0.1735	0.028*
C2	0.6344 (4)	0.4814 (6)	0.2500	0.0280 (9)
H2A	0.5234	0.4971	0.2500	0.034*	0.614 (7)
H2B	0.6565	0.3578	0.2500	0.034*	0.386 (7)
O4A	0.4821 (4)	0.4546 (7)	0.2500	0.0288 (14)	0.614 (7)
H4A	0.4429	0.5079	0.2067	0.035*	0.307 (4)
O4B	0.6225 (16)	0.3254 (10)	0.2500	0.071 (5)	0.386 (7)
H4B	0.6301	0.2665	0.2038	0.085*	0.193 (4)
N1	0.6289 (2)	0.4895 (3)	0.10193 (12)	0.0197 (4)
H2	0.6785	0.5282	0.0576	0.024*
H3	0.5303	0.5217	0.0995	0.024*
H4	0.6348	0.3738	0.1038	0.024*
O5	0.0333 (10)	0.8202 (10)	0.2500	0.063 (3)	0.50
H5	0.0134	0.7591	0.2956	0.075*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.01189 (19)	0.0156 (2)	0.0135 (2)	0.000	0.000	−0.00179 (14)
P1	0.0180 (3)	0.0157 (3)	0.0186 (3)	−0.0003 (2)	−0.0065 (2)	−0.0010 (2)
O1	0.0190 (8)	0.0317 (10)	0.0170 (8)	0.0083 (7)	−0.0034 (7)	−0.0029 (7)
O2	0.0190 (8)	0.0211 (9)	0.0219 (8)	−0.0053 (7)	0.0026 (7)	−0.0059 (7)
O3	0.0162 (9)	0.0245 (11)	0.097 (2)	0.0013 (8)	−0.0156 (11)	−0.0235 (12)
C1	0.0217 (12)	0.0284 (13)	0.0189 (12)	−0.0072 (10)	−0.0013 (10)	−0.0016 (10)
C2	0.0234 (18)	0.043 (2)	0.0173 (16)	−0.0162 (17)	0.000	0.000
O4A	0.012 (2)	0.059 (3)	0.0146 (19)	−0.0111 (19)	0.000	0.000
O4B	0.174 (13)	0.016 (4)	0.022 (4)	−0.029 (6)	0.000	0.000
N1	0.0168 (10)	0.0230 (11)	0.0195 (10)	−0.0010 (8)	0.0024 (8)	−0.0028 (8)
O5	0.113 (7)	0.062 (5)	0.013 (3)	−0.052 (5)	0.000	0.000

Geometric parameters (Å, º)

Zn1—O1^i	1.9314 (17)	C2—O4B	1.229 (9)
Zn1—O1^ii	1.9314 (17)	C2—O4A	1.365 (5)
Zn1—O2	1.9501 (16)	C2—C1^iv	1.512 (3)
Zn1—O2^iii	1.9501 (16)	C2—H2A	0.9900
P1—O3	1.4999 (19)	C2—H2B	0.9900
P1—O1	1.5197 (17)	O4A—H2A	0.4951
P1—O2	1.5264 (17)	O4A—H4A	0.9023
P1—H1	1.3200	O4B—H2B	0.3939
O1—Zn1^i	1.9314 (17)	O4B—H4B	0.8991
C1—N1	1.481 (3)	N1—H2	0.9100
C1—C2	1.512 (3)	N1—H3	0.9100
C1—H1A	0.9900	N1—H4	0.9100
C1—H1B	0.9900	O5—H5	0.9142
O1^i—Zn1—O1^ii	116.86 (10)	O4A—C2—C1^iv	116.1 (2)
O1^i—Zn1—O2	112.29 (8)	O4B—C2—C1	116.8 (3)
O1^ii—Zn1—O2	107.53 (7)	O4A—C2—C1	116.1 (2)
O1^i—Zn1—O2^iii	107.53 (7)	C1^iv—C2—C1	110.9 (3)
O1^ii—Zn1—O2^iii	112.29 (8)	O4B—C2—H2A	92.2
O2—Zn1—O2^iii	98.92 (10)	C1^iv—C2—H2A	109.0
O3—P1—O1	112.76 (11)	C1—C2—H2A	109.0
O3—P1—O2	110.78 (12)	O4A—C2—H2B	92.5
O1—P1—O2	112.62 (10)	C1^iv—C2—H2B	109.7
O3—P1—H1	106.7	C1—C2—H2B	109.7
O1—P1—H1	106.7	H2A—C2—H2B	108.5
O2—P1—H1	106.7	C2—O4A—H4A	108.0
P1—O1—Zn1^i	126.51 (10)	H2A—O4A—H4A	88.4
P1—O2—Zn1	134.82 (10)	C2—O4B—H4B	120.4
N1—C1—C2	110.7 (2)	H2B—O4B—H4B	105.9
N1—C1—H1A	109.5	C1—N1—H2	109.5
C2—C1—H1A	109.5	C1—N1—H3	109.5
N1—C1—H1B	109.5	H2—N1—H3	109.5
C2—C1—H1B	109.5	C1—N1—H4	109.5
H1A—C1—H1B	108.1	H2—N1—H4	109.5
O4B—C2—O4A	76.2 (7)	H3—N1—H4	109.5
O4B—C2—C1^iv	116.8 (3)
O3—P1—O1—Zn1^i	103.54 (17)	O1^ii—Zn1—O2—P1	−23.26 (18)
O2—P1—O1—Zn1^i	−22.74 (17)	O2^iii—Zn1—O2—P1	−140.15 (19)
O3—P1—O2—Zn1	168.39 (15)	N1—C1—C2—O4B	45.9 (8)
O1—P1—O2—Zn1	−64.28 (18)	N1—C1—C2—O4A	−41.3 (5)
O1^i—Zn1—O2—P1	106.65 (16)	N1—C1—C2—C1^iv	−176.8 (2)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O4A—H4A···O3	0.90	2.17	3.072 (4)	179
O4B—H4B···O3^v	0.90	1.96	2.863 (5)	179
N1—H2···O2^vi	0.91	1.92	2.822 (3)	168
N1—H3···O3	0.91	1.85	2.738 (3)	166
N1—H4···O3^v	0.91	1.85	2.763 (3)	177
O5—H5···O1^iv	0.91	1.97	2.801 (4)	150

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