Triethano­lammonium di­hydrogenphosphite

The title compound, [HN(C₂H₄OH)₃](H₂PO₃) or C₆H₁₆NO₃⁺·H₂PO₃⁻, is isostructural with its hydrogenselenite congener and contains a network of partially disordered triethano­lammonium cations and di­hydrogenphosphite anions [for the latter species: d_av(P—O) = 1.514 (2) Å and θ_av(O—P—O) = 111.9 (2)°]. The [H₂PO₃]⁻ units are linked into a polymeric chain by P—O—H...O—P hydrogen bonds along the polar [010] direction, with the chains crosslinked into (001) sheets by way of O—H...O bonds involving the organic species. Some C—H...O interactions may also be present [d_av(H...O) = 2.45 Å, θ_av(C—H...O) = 158° and d_av(C...O) = 3.364 (4) Å]. The [HN(C₂H₄OH)₃]⁺ cation contains a typical trifurcated intramolecular N—H...(O,O,O) hydrogen bond [d_av(H...O) = 2.31 Å and θ_av(N—H...O) = 112.7°].

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](P-O) = 0.002 Å
• R factor = 0.039
• wR factor = 0.086
• Data-to-parameter ratio = 16.9

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .....       0.98

Alert level C
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ..          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .....          ?
PLAT242_ALERT_2_C Check Low    U(eq) as Compared to Neighbors ..           P1
PLAT301_ALERT_3_C Main Residue  Disorder .......................      18.00 Perc.
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O5     -   H13    =       1.06 Ang.
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O6     -   H18    =       1.01 Ang.
PLAT355_ALERT_3_C Long    O-H Bond (0.82A)   O3     -   H2     =       1.04 Ang.

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.63
           From the CIF: _reflns_number_total               2362
           Count of symmetry unique reflns         1393
           Completeness (_total/calc)            169.56%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       969
           Fraction of Friedel pairs measured     0.696
           Are heavy atom types Z>Si present          yes

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

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

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S1. Comment

Triethanolammonium dihydrogenphosphite, [HN(C₂H₄OH)₃](H₂PO₃), (I), is isostructural with the recently reported triethanolammonium h ydrogenselenite, [HN(C₂H₄OH)₃](HSeO₃), which shows cytotoxic activity (Lukevics et al., 2002).

The structure of (I) consists of triethanolammonium cations and dihydrogenphosphate anions (Fig. 1). The triethanolammonium cation is partially disordered over two positions [major component: atoms C1, C3, and C5 with an occupancy of 0.866 (5) and d_av(N—C) = 1.503 (4) Å; minor component: atoms C11, C13, and C15 with an occupancy of 0.134 (5) and d_av(N—C) = 1.50 (2) Å]. Otherwise, it exibits a typical (Yilmaz et al. 1996; Demir et al., 2003) tripodal conformation [for the major component; d_av(C—C) = 1.474 (4) Å and d_av(C—O) = 1.408 (4) Å] in which the ammonium H atom forms an intramolecular trifurcated hydrogen bond with the O atoms of the three ethanol groups [d_av(H···O) = 2.31 Å and θ_av(N—H···O) = 112.7°]. The dihydrogenphosphite group shows its usual (Gordon & Harrison, 2003) pseudo-pyramidal geometry [d_av(P—O) = 1.514 (2) Å and θ_av(O—P—O) = 111.9 (2)°], with the protonated P—O3 vertex showing its expected lengthening relative to the other two P—O bonds.

The component species in (I) interact by means of an extensive network of O—H···O hydrogen bonds and C—H···O intermolecular contacts (Table 2). The H₂PO₃ units are linked into a polymeric chain by P—O—H···O—P hydrogen bonds in the polar [010] direction (Fig. 2). A similar dihydrogenphosphite chain was seen in (CN₃H₆)(H₂PO₃) (Harrison, 2003). The organic species crosslink the chains in the a direction by way of O_E—H···O_P (E = ethanol and P = phosphite) hydrogen bonds, such that each cation makes two hydrogen bonds to one adjacent phosphite moiety (Fig. 1). This results in (001) slabs (Fig. 3). The possible C—H···O interactions [d_av(H···O) = 2.45 Å, θ_av(C—H···O) = 158° and d_av(C···O) = 3.364 (4) Å] were identified in a PLATON (Spek, 2003) analysis of the structure. Those involving H5, H9 and H14 provide additional coherence between adjacent organic molecules, in the c direction for H5 and in the b direction for H9 and H14. The bond involving H10 links a [HN(C₂H₄OH)₃]⁺ grouping with a (H₂PO₃)⁻ anion in the a direction.

Triethanolammonium dihydrogenphosphate, [HN(C₂H₄OH)₃](H₂PO₄) (Demir et al., 2003) crystallizes in the same space group and has a rather similar structure to (I) in which chains of [H₂PO₄]⁻ anions are crosslinked into sheets by the triethanolammonium cations. However, the (H₂PO₄)⁻ moieties in [HN(C₂H₄OH)₃](H₂PO₄) are linked together by a distinctly different hydrogen bonding motif involving alternating single and double P—O—H···O—P links.

S2. Experimental

H₃PO₃ (0.81 g, 1 mmol) and triethanolamine (1.49 g, 1 mmol) were dissolved in 20 ml deionized water in a Petri dish to result in a clear solution. Rod-shaped crystals of (I) grew as the water evaporated over the course of a few days. These colourless transparent crystals were rinsed with acetone and dried in air.

S3. Refinement

The site occupancies of the two conformations (C1, C3, C5 and their attached H atoms/C11, C13, C15 and their attached H atoms) of the partially disordered organic species were constrained to sum to unity. The O—H and N—H hydrogen atoms were found in difference maps and were refined by riding in their as-found positions. The H atoms bonded to carbon and phosphorus were placed in calculated positions [d(C—H) = 0.97 Å and d(P—H) = 1.32 Å] and refined by riding. For all H atoms, the constraint U_iso(H) = 1.2U_eq(parent atom) was applied.

Computing details

Data collection: SMART (Bruker, 1999); cell refinement: SAINT (Bruker, 1999); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97; molecular graphics: ORTEP-3 (Farrugia, 1997) and ATOMS (Shape Software, 1999); software used to prepare material for publication: SHELXL97.

Figures

	Fig. 1. View of (I) (50% displacement ellipsoids). H atoms are drawn as small spheres of arbitrary radius and H bonds are indicated by dashed lines. Only the major orientation of the organic molecule is shown; all C—H hydrogen atoms have been omitted for clarity.
	Fig. 2. Detail of a dihydrogenphosphite chain and the pendant organic species (major orientation only) in (I). Colour key: [H2PO3]^− pseudo-tetrahedra yellow, O atoms red, C atoms blue, N atoms purple, H atoms grey. The H···O portions of the N—H···O and O—H···O hydrogen bonds are highlighted in green and yellow, respectively. All C—H hydrogen atoms omitted for clarity.
	Fig. 3. [010] projection of (I) showing the (001) sheet-like arrangement of [HN(C2H4OH)3]^+ (major orientation only) and (H2PO3)^− moieties. Colour key as in Fig. 1. H3 and all C—H hydrogen atoms have been omitted for clarity.

(I)

Crystal data

C6H16NO3^+·H2PO3^−	F(000) = 248
Mr = 231.18	Dx = 1.419 Mg m^−3
Monoclinic, P21	Mo Kα radiation, λ = 0.71073 Å
a = 7.9280 (7) Å	Cell parameters from 1408 reflections
b = 5.5192 (5) Å	θ = 2.7–23.3°
c = 12.7940 (11) Å	µ = 0.26 mm^−1
β = 104.803 (2)°	T = 293 K
V = 541.24 (8) Å^3	Rod, colourless
Z = 2	0.52 × 0.08 × 0.07 mm

Data collection

Bruker SMART1000 CCD diffractometer	2362 independent reflections
Radiation source: fine-focus sealed tube	1743 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
ω scans	θmax = 27.6°, θmin = 2.7°
Absorption correction: multi-scan (SADABS; Bruker, 1999)	h = −10→10
Tmin = 0.876, Tmax = 0.977	k = −7→7
3955 measured reflections	l = −11→16

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: difmap (N-H and O-H) and geom (C-H, P-H)
R[F^2 > 2σ(F^2)] = 0.039	H-atom parameters constrained
wR(F^2) = 0.087	w = 1/[σ^2(Fo^2) + (0.0414P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 0.94	(Δ/σ)max < 0.001
2362 reflections	Δρmax = 0.18 e Å^−3
140 parameters	Δρmin = −0.24 e Å^−3
1 restraint	Absolute structure: Flack (1983), 1128 Friedel pairs
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: 0.11 (12)

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)
P1	−0.01075 (9)	0.62827 (12)	0.13758 (5)	0.04477 (18)
H1	−0.1527	0.5016	0.0944	0.054*
O1	0.1222 (2)	0.5583 (4)	0.07939 (13)	0.0577 (5)
O2	0.0316 (2)	0.5861 (4)	0.25649 (13)	0.0604 (5)
O3	−0.0608 (3)	0.9015 (4)	0.11817 (15)	0.0701 (7)
H2	−0.0925	0.9635	0.0384	0.084*
N1	0.5510 (2)	0.1123 (4)	0.29094 (14)	0.0407 (4)
H3	0.5417	0.2756	0.2976	0.049*
C1	0.4568 (5)	−0.0011 (6)	0.3667 (3)	0.0571 (10)	0.866 (5)
H4	0.4319	−0.1692	0.3464	0.069*	0.866 (5)
H5	0.5322	0.0017	0.4395	0.069*	0.866 (5)
C11	0.376 (3)	0.017 (4)	0.2955 (19)	0.047 (5)*	0.134 (5)
H11A	0.2998	0.0272	0.2232	0.056*	0.134 (5)
H11B	0.3903	−0.1539	0.3138	0.056*	0.134 (5)
C2	0.2917 (4)	0.1247 (6)	0.3658 (2)	0.0617 (7)
H6	0.2052	0.0899	0.2988	0.074*
H7	0.2473	0.0670	0.4253	0.074*
O4	0.3212 (2)	0.3773 (4)	0.37577 (13)	0.0568 (5)
H8	0.2245	0.4521	0.3332	0.068*
C3	0.7434 (5)	0.0539 (6)	0.3234 (3)	0.0575 (10)	0.866 (5)
H9	0.7590	−0.1125	0.3484	0.069*	0.866 (5)
H10	0.7902	0.0684	0.2607	0.069*	0.866 (5)
C13	0.695 (3)	0.055 (4)	0.3870 (18)	0.047 (5)*	0.134 (5)
H13A	0.6479	0.0524	0.4499	0.056*	0.134 (5)
H13B	0.7366	−0.1071	0.3781	0.056*	0.134 (5)
C4	0.8410 (4)	0.2145 (6)	0.4091 (2)	0.0621 (9)
H11	0.8060	0.1831	0.4751	0.074*
H12	0.9646	0.1791	0.4228	0.074*
O5	0.8128 (2)	0.4609 (4)	0.38149 (14)	0.0569 (5)
H13	0.8980	0.5182	0.3349	0.068*
C5	0.4654 (6)	0.0520 (6)	0.1755 (3)	0.0561 (10)	0.866 (5)
H14	0.5093	−0.1022	0.1572	0.067*	0.866 (5)
H15	0.3405	0.0364	0.1661	0.067*	0.866 (5)
C15	0.599 (3)	0.073 (3)	0.1850 (13)	0.037 (5)*	0.134 (5)
H15A	0.7231	0.0987	0.1951	0.044*	0.134 (5)
H15B	0.5726	−0.0931	0.1610	0.044*	0.134 (5)
C6	0.4999 (5)	0.2416 (6)	0.1023 (2)	0.0600 (8)
H16	0.6203	0.2300	0.0984	0.072*
H17	0.4256	0.2151	0.0302	0.072*
O6	0.4694 (3)	0.4742 (3)	0.13740 (14)	0.0546 (5)
H18	0.3386	0.4991	0.1132	0.066*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0462 (3)	0.0469 (4)	0.0403 (3)	0.0004 (4)	0.0094 (2)	0.0037 (3)
O1	0.0603 (11)	0.0684 (13)	0.0446 (10)	0.0085 (9)	0.0134 (8)	−0.0144 (9)
O2	0.0685 (12)	0.0703 (14)	0.0452 (10)	0.0152 (11)	0.0195 (8)	0.0224 (10)
O3	0.1132 (17)	0.0614 (14)	0.0419 (11)	0.0325 (12)	0.0310 (11)	0.0124 (10)
N1	0.0509 (11)	0.0315 (10)	0.0433 (10)	0.0003 (11)	0.0188 (8)	−0.0001 (10)
C1	0.066 (2)	0.050 (2)	0.063 (2)	0.0034 (15)	0.0295 (19)	0.0187 (16)
C2	0.0620 (17)	0.0655 (19)	0.0651 (18)	0.001 (2)	0.0297 (14)	0.0109 (19)
O4	0.0551 (11)	0.0637 (13)	0.0489 (12)	0.0083 (10)	0.0082 (9)	−0.0073 (9)
C3	0.067 (2)	0.0458 (19)	0.069 (2)	0.0192 (15)	0.034 (2)	0.0099 (16)
C4	0.0487 (17)	0.078 (2)	0.0560 (18)	0.0065 (14)	0.0071 (15)	0.0189 (15)
O5	0.0573 (12)	0.0593 (12)	0.0546 (12)	−0.0040 (10)	0.0150 (10)	−0.0004 (9)
C5	0.081 (3)	0.0437 (18)	0.0459 (19)	−0.0153 (16)	0.0209 (17)	−0.0146 (14)
C6	0.071 (2)	0.0663 (19)	0.0463 (16)	−0.0012 (15)	0.0221 (15)	−0.0100 (15)
O6	0.0626 (13)	0.0486 (12)	0.0522 (12)	−0.0039 (9)	0.0137 (10)	0.0028 (9)

Geometric parameters (Å, º)

P1—O1	1.4883 (19)	O4—H8	0.9173
P1—O2	1.4901 (16)	C3—C4	1.467 (5)
P1—O3	1.563 (2)	C3—H9	0.9700
P1—H1	1.3200	C3—H10	0.9700
O3—H2	1.0445	C13—C4	1.42 (2)
N1—C13	1.483 (19)	C13—H13A	0.9700
N1—C11	1.50 (2)	C13—H13B	0.9700
N1—C5	1.497 (4)	C4—O5	1.408 (3)
N1—C1	1.503 (3)	C4—H11	0.9700
N1—C3	1.509 (4)	C4—H12	0.9700
N1—C15	1.514 (16)	O5—H13	1.0569
N1—H3	0.9100	C5—C6	1.476 (4)
C1—C2	1.480 (4)	C5—H14	0.9700
C1—H4	0.9700	C5—H15	0.9700
C1—H5	0.9700	C15—C6	1.477 (16)
C11—C2	1.39 (2)	C15—H15A	0.9700
C11—H11A	0.9700	C15—H15B	0.9700
C11—H11B	0.9700	C6—O6	1.401 (3)
C2—O4	1.414 (4)	C6—H16	0.9700
C2—H6	0.9700	C6—H17	0.9700
C2—H7	0.9700	O6—H18	1.0131
O1—P1—O2	117.83 (11)	C4—C3—H9	109.1
O1—P1—O3	110.75 (12)	N1—C3—H9	109.1
O2—P1—O3	107.14 (11)	C4—C3—H10	109.1
O1—P1—H1	106.9	N1—C3—H10	109.1
O2—P1—H1	106.9	H9—C3—H10	107.9
O3—P1—H1	106.9	C4—C13—N1	116.6 (14)
P1—O3—H2	117.3	C4—C13—H13A	108.1
C13—N1—C11	114.7 (12)	N1—C13—H13A	108.1
C5—N1—C1	111.7 (2)	C4—C13—H13B	108.1
C5—N1—C3	113.3 (2)	N1—C13—H13B	108.1
C1—N1—C3	111.5 (2)	H13A—C13—H13B	107.3
C13—N1—C15	113.3 (11)	O5—C4—C13	118.6 (8)
C11—N1—C15	115.4 (11)	O5—C4—C3	112.1 (2)
C13—N1—H3	101.3	O5—C4—H11	109.2
C11—N1—H3	104.3	C3—C4—H11	109.2
C5—N1—H3	106.6	O5—C4—H12	109.2
C1—N1—H3	106.6	C3—C4—H12	109.2
C3—N1—H3	106.6	H11—C4—H12	107.9
C15—N1—H3	105.8	C4—O5—H13	110.3
C2—C1—N1	112.6 (2)	C6—C5—N1	110.9 (2)
C2—C1—H4	109.1	C6—C5—H14	109.5
N1—C1—H4	109.1	N1—C5—H14	109.5
C2—C1—H5	109.1	C6—C5—H15	109.5
N1—C1—H5	109.1	N1—C5—H15	109.5
H4—C1—H5	107.8	H14—C5—H15	108.0
C2—C11—N1	118.7 (14)	C6—C15—N1	109.9 (11)
C2—C11—H11A	107.6	C6—C15—H15A	109.7
N1—C11—H11A	107.6	N1—C15—H15A	109.7
C2—C11—H11B	107.6	C6—C15—H15B	109.7
N1—C11—H11B	107.6	N1—C15—H15B	109.7
H11A—C11—H11B	107.1	H15A—C15—H15B	108.2
C11—C2—O4	112.6 (8)	O6—C6—C5	111.8 (2)
O4—C2—C1	109.6 (2)	O6—C6—C15	116.9 (7)
O4—C2—H6	109.7	O6—C6—H16	109.3
C1—C2—H6	109.7	C5—C6—H16	109.3
O4—C2—H7	109.7	O6—C6—H17	109.3
C1—C2—H7	109.7	C5—C6—H17	109.3
H6—C2—H7	108.2	H16—C6—H17	107.9
C2—O4—H8	107.2	C6—O6—H18	105.9
C4—C3—N1	112.3 (3)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H2···O1^i	1.04	1.56	2.597 (3)	175
N1—H3···O6	0.91	2.27	2.760 (3)	114
N1—H3···O4	0.91	2.29	2.765 (3)	112
N1—H3···O5	0.91	2.37	2.850 (3)	113
O4—H8···O2	0.92	1.76	2.672 (2)	176
O6—H18···O1	1.01	1.69	2.702 (3)	176
O5—H13···O2^ii	1.06	1.68	2.731 (2)	175
C1—H5···O4^iii	0.97	2.45	3.382 (4)	161
C3—H9···O5^iv	0.97	2.41	3.370 (4)	170
C3—H10···O3^v	0.97	2.58	3.478 (4)	154
C5—H14···O6^iv	0.97	2.36	3.227 (4)	148

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