Pentane-1,5-bis­phospho­nic acid

The title compound, C₅H₁₄O₆P₂ or (CH₂)₅[PO(OH)₂]₂, commonly known as 1,5-pentyl­enebisphospho­nic acid, was prepared by hydro­lysis of the corresponding tetra­eth­yl pentyl­enebisphospho­nate with 6 M HCl. Crystals suitable for X-ray crystallography were obtained upon cooling a hot saturated 1:1 (v/v) acetone-ethanol solution of the acid to room temperature. The compound exists in the solid state as a hydrogen-bonded extended structure.

Key indicators

• Single-crystal X-ray study
• T = 100 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.036
• wR factor = 0.096
• Data-to-parameter ratio = 18.7

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Computing details

Data collection: CrysAlis CCD (Oxford, 2005); cell refinement: CrysAlis RED (Oxford, 2005); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: XP in SHELXTL-Plus (Sheldrick, 1991); software used to prepare material for publication: WinGX (Farrugia, 1999).

Pentane-1,5-bisphosphonic acid

Crystal data

C5H14O6P2	F(000) = 488
Mr = 232.10	Dx = 1.540 Mg m^−3
Monoclinic, P21/c	Melting point: 426(1) K
Hall symbol: -P 2ybc	Mo Kα radiation, λ = 0.71073 Å
a = 9.4776 (9) Å	Cell parameters from 2233 reflections
b = 10.7072 (12) Å	θ = 4.3–30.0°
c = 10.0023 (11) Å	µ = 0.43 mm^−1
β = 99.463 (8)°	T = 100 K
V = 1001.21 (18) Å^3	Prism, colorless
Z = 4	0.21 × 0.13 × 0.06 mm

Data collection

Oxford Diffraction Xcalibur3 CCD area-detector diffractometer	2285 independent reflections
Radiation source: Enhance (Mo) X-ray source	1789 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.020
φ and ω scans	θmax = 27.5°, θmin = 4.3°
Absorption correction: numerical Analytical numerical absorption correction using a multifaceted crystal model based on expressions derived by Clark & Reid (1995)	h = −7→12
Tmin = 0.858, Tmax = 0.950	k = −13→12
5150 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.036	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.096	H-atom parameters constrained
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0522P)^2 + 0.1207P] where P = (Fo^2 + 2Fc^2)/3
2285 reflections	(Δ/σ)max = 0.001
122 parameters	Δρmax = 0.39 e Å^−3
0 restraints	Δρmin = −0.39 e Å^−3

Special details

Experimental. Standards collected every 50 frames.

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
P1	0.93069 (5)	0.81930 (4)	1.18896 (5)	0.01430 (15)
P2	0.26723 (5)	0.87138 (5)	0.55512 (5)	0.01477 (15)
O1	0.91350 (14)	0.67613 (12)	1.16679 (15)	0.0196 (3)
H1	0.9867	0.6475	1.1451	0.029*
O2	0.85900 (15)	0.84123 (13)	1.31561 (15)	0.0203 (3)
H2	0.8615	0.9159	1.3342	0.030*
O3	1.08473 (13)	0.86153 (12)	1.20715 (14)	0.0164 (3)
O4	0.27932 (14)	0.91450 (13)	0.40969 (14)	0.0196 (3)
H4	0.2061	0.8956	0.3580	0.029*
O5	0.25476 (15)	0.72654 (12)	0.55174 (15)	0.0196 (3)
H5	0.1956	0.7043	0.5982	0.029*
O6	0.14470 (14)	0.92930 (12)	0.61215 (14)	0.0190 (3)
C1	0.8320 (2)	0.89698 (18)	1.0465 (2)	0.0187 (4)
H1A	0.8272	0.9849	1.0686	0.022*
H1B	0.8854	0.8903	0.9719	0.022*
C2	0.6783 (2)	0.85059 (19)	0.9963 (2)	0.0191 (4)
H2A	0.6785	0.7605	0.9859	0.023*
H2B	0.6179	0.8712	1.0626	0.023*
C3	0.6189 (2)	0.91160 (19)	0.8607 (2)	0.0199 (4)
H3A	0.6870	0.8993	0.7992	0.024*
H3B	0.6110	1.0008	0.8747	0.024*
C4	0.4730 (2)	0.86224 (19)	0.7928 (2)	0.0190 (4)
H4A	0.4002	0.8865	0.8455	0.023*
H4B	0.4753	0.7718	0.7888	0.023*
C5	0.4364 (2)	0.91589 (19)	0.6488 (2)	0.0186 (4)
H5A	0.5104	0.8903	0.5981	0.022*
H5B	0.4394	1.0063	0.6550	0.022*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0135 (3)	0.0138 (3)	0.0154 (3)	−0.00006 (19)	0.00185 (19)	−0.00058 (19)
P2	0.0131 (3)	0.0160 (3)	0.0147 (3)	−0.00038 (19)	0.00083 (19)	−0.00020 (19)
O1	0.0155 (7)	0.0140 (7)	0.0301 (8)	−0.0006 (6)	0.0062 (6)	−0.0043 (6)
O2	0.0258 (8)	0.0172 (7)	0.0194 (8)	−0.0015 (6)	0.0084 (6)	−0.0027 (6)
O3	0.0133 (7)	0.0178 (7)	0.0171 (7)	−0.0007 (5)	−0.0008 (5)	−0.0023 (5)
O4	0.0157 (7)	0.0269 (8)	0.0152 (7)	−0.0046 (6)	−0.0009 (6)	0.0017 (6)
O5	0.0205 (8)	0.0173 (7)	0.0228 (8)	−0.0001 (6)	0.0087 (6)	−0.0018 (6)
O6	0.0172 (7)	0.0157 (7)	0.0245 (8)	−0.0005 (5)	0.0051 (6)	−0.0021 (6)
C1	0.0170 (10)	0.0202 (10)	0.0187 (10)	−0.0016 (8)	0.0023 (8)	0.0013 (8)
C2	0.0157 (10)	0.0226 (11)	0.0185 (10)	0.0002 (8)	0.0010 (8)	−0.0013 (8)
C3	0.0144 (9)	0.0229 (11)	0.0210 (11)	0.0002 (8)	−0.0014 (8)	0.0049 (8)
C4	0.0174 (10)	0.0211 (11)	0.0182 (10)	−0.0010 (8)	0.0022 (8)	0.0016 (8)
C5	0.0157 (10)	0.0220 (10)	0.0177 (10)	−0.0026 (8)	0.0013 (8)	0.0017 (8)

Geometric parameters (Å, º)

P1—O1	1.5536 (14)	C1—H1A	0.9700
P1—O2	1.5506 (14)	C1—H1B	0.9700
P1—O3	1.5105 (14)	C2—C3	1.528 (3)
P1—C1	1.777 (2)	C2—H2A	0.9700
P2—O4	1.5483 (14)	C2—H2B	0.9700
P2—O5	1.5552 (14)	C3—H3A	0.9700
P2—O6	1.5088 (14)	C3—H3B	0.9700
P2—C5	1.784 (2)	C4—C3	1.531 (3)
O1—H1	0.8200	C4—C5	1.536 (3)
O2—H2	0.8200	C4—H4A	0.9700
O4—H4	0.8200	C4—H4B	0.9700
O5—H5	0.8200	C5—H5A	0.9700
C1—C2	1.543 (3)	C5—H5B	0.9700
O1—P1—C1	108.56 (9)	C1—C2—H2B	109.7
O2—P1—O1	102.49 (8)	C3—C2—C1	109.95 (16)
O2—P1—C1	109.92 (9)	C3—C2—H2A	109.7
O3—P1—O1	112.90 (7)	C3—C2—H2B	109.7
O3—P1—O2	113.64 (8)	H2A—C2—H2B	108.2
O3—P1—C1	109.10 (9)	C2—C3—C4	114.84 (16)
O4—P2—C5	102.41 (9)	C2—C3—H3A	108.6
O4—P2—O5	107.10 (8)	C2—C3—H3B	108.6
O5—P2—C5	109.65 (9)	C4—C3—H3A	108.6
O6—P2—O4	114.40 (8)	C4—C3—H3B	108.6
O6—P2—O5	110.96 (8)	H3A—C3—H3B	107.5
O6—P2—C5	111.89 (9)	C3—C4—C5	109.55 (16)
P1—O1—H1	109.5	C3—C4—H4A	109.8
P1—O2—H2	109.5	C3—C4—H4B	109.8
P2—O4—H4	109.5	C5—C4—H4A	109.8
P2—O5—H5	109.5	C5—C4—H4B	109.8
P1—C1—H1A	108.0	H4A—C4—H4B	108.2
P1—C1—H1B	108.0	P2—C5—H5A	108.3
C2—C1—P1	117.01 (14)	P2—C5—H5B	108.3
C2—C1—H1A	108.0	C4—C5—P2	115.94 (13)
C2—C1—H1B	108.0	C4—C5—H5A	108.3
H1A—C1—H1B	107.3	C4—C5—H5B	108.3
C1—C2—H2A	109.7	H5A—C5—H5B	107.4
O1—P1—C1—C2	46.64 (17)	O6—P2—C5—C4	69.32 (17)
O2—P1—C1—C2	−64.73 (17)	P1—C1—C2—C3	−170.42 (14)
O3—P1—C1—C2	170.05 (14)	C1—C2—C3—C4	173.63 (16)
O4—P2—C5—C4	−167.70 (15)	C3—C4—C5—P2	−178.53 (14)
O5—P2—C5—C4	−54.23 (17)	C5—C4—C3—C2	−171.36 (17)

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O6^i	0.82	1.79	2.6016 (18)	173
O2—H2···O6^ii	0.82	1.75	2.5629 (19)	174
O4—H4···O3^iii	0.82	1.78	2.5688 (19)	162
O5—H5···O3^iv	0.82	1.78	2.5935 (19)	172

Symmetry codes: (i) x+1, −y+3/2, z+1/2; (ii) −x+1, −y+2, −z+2; (iii) x−1, y, z−1; (iv) x−1, −y+3/2, z−1/2.