4,4'-Tri­methyl­enedipyridinium bis­[carboxy­methyl­phos­pho­nate(1-)]: a three-dimensional framework structure built from O-H...O, N-H...O and C-H...O hydrogen bonds

In the title compound, C₁₃H₁₆N₂²⁺·2C₂H₄O₅P^-, the cation lies across a twofold rotation axis in space group Fdd2. The anions are linked into molecular ladders by two O-H...O hydrogen bonds [H...O = 1.73 and 1.77 Å, O...O = 2.538 (2) and 2.598 (3) Å, and O-H...O = 160 and 170°], these ladders are linked into sheets by a single type of N-H...O hydrogen bond [H...O = 1.75 Å, N...O = 2.624 (3) Å and N-H...O = 171°] and the sheets are linked into a three-dimensional framework by a single type of C-H...O hydrogen bond [H...O = 2.48 Å, C...O = 3.419 (4) Å and C-H...O = 167°].

S1. Comment

We have recently described the supramolecular structures of the adducts formed by carboxymethylphosphonic acid [phosphonoacetic acid, HOOCCH₂P(O)(OH)₂] with 4,4'-bipyridyl (NC₅H₄—C₅H₄N), where a 1:1 adduct is formed, and 1,2-bis(4-pyridyl)ethane (NC₅H₄—CH₂CH₂—C₅H₄N), where a 1:2 adduct is formed (Bowes et al. 2003). These two adducts are both salts, with constitutions C₁₀H₉N₂⁺·C₂H₄O₅P⁻ and C₁₂H₁₄N₂²⁺·2C₂H₄O₅P⁻, respectively. In the 4,4'-bipyridyl adduct, the anions form simple C(4) chains, which are linked by the cations into sheets of R⁶₆(38) rings, which in turn are linked by multiple C—H···O hydrogen bonds. In the 1,2-bis(4-pyridyl) adduct, on the other hand, the anions alone form sheets of alternating R²₂(12) and R⁶₆(28) rings, which are linked by the cations into a three-dimensional framework. In continuation of this study, we have now prepared and structurally characterized the title compound, (I), the adduct formed between 4,4'-trimethylenedipyridine and carboxymethylphosphonic acid.

Compound (I) (Fig. 1) is a salt, [HNC₅H₄(CH₂)₃C₅H₄NH]²⁺·2[HOOCCH₂P(O)₂(OH)]⁻, in which complete transfer of H atoms, to the N atome from one of the phosphonate O atoms, has occurred. The cation lies across a twofold rotation axis in space group Fdd2, and for the reference cation this axis was selected as that along (1/2, 1/2, z). The anion lies in a general position. In the anion, the P—O and C—O distances (Table 1) are fully consistent with the H-atom locations deduced from difference maps. In the cation, the central C14—C17—C18—C17ⁱ—C14ⁱ fragment [symmetry code: (i) 1 − x, 1 − y, z] is effectively planar, with an all-trans conformation (Table 1), but the pyridinium ring is rotated out of this plane. All other bond lengths and angles have unexceptional values.

The ions are linked by a small number of hydrogen bonds (Table 2) into a single three-dimensional framework, within which it is possible to identify substructures in one and two dimensions. The anions alone form a one-dimensional substructure in the form of a molecular ladder, or chain of edge-fused rings. The anions and cations are linked into sheets by a combination of all of the hard (Desiraju & Steiner, 1999) hydrogen bonds, all of which have D···A distances that are short for their types, and the sheets are themselves linked into a continuous framework by a single soft C—H···O hydrogen bond.

Phosphonic acid atom O3 in the anion at (x, y, z) acts as a hydrogen-bond donor to phosphonate atom O4 in the anion at (x, y, 1 + z), so generating by translation a C(4) chain running parallel to the [001] direction. In addition, carboxyl atom O1 at (x, y, z) acts as a hydrogen-bond donor to phosphonate atom O5 at (1 − x, 0.5 − y, −0.5 + z), so producing a C(6) chain parallel to [001] and generated by the 2₁ screw axis along (1/2, 1/4, z). The combination of the C(4) and C(6) motifs generates a molecular ladder along [001] (Fig. 2), which can alternatively be regarded as a chain of edge-fused R³₃(16) rings. The anion substructure thus contains two of the three hydrogen-bonded motifs most characteristic of phosphonic acids and phosphonate anions, but the third such motif, R²₂(8) rings, is absent.

There are eight [001] ladders running through each unit cell, viz. two each generated by screw axes at x = 0, 1/4, 0.5 and 0.75. For each of these values of x, the anion ladders are linked by cations, via N—H···O hydrogen bonds, into (100) sheets. The N atoms at (x, y, z) and (1 − x, 1 − y, z) are both components of the cation lying across the twofold rotation axis along (1/2, 1/2, z). These atoms act as hydrogen-bond donors to phosphonate atoms O5 in the anions at (x, y, z) and (1 − x, 1 − y, z), respectively, which lie in the anion ladders along (1/2, 1/4, z) and ().5, 3/4, z), respectively. Propagation of these hydrogen bonds thus links all of the cations lying across rotation axes having x = 1/2, and all of the anion ladders generated by 2₁ axes having x = 1/2, into a (100) sheet built from R⁶₆(40) rings (Fig. 3).

Four (100) sheets pass through each unit cell, and these sheets are linked by a single C—H···O hydrogen bond (Table 2) into a single three-dimensional framework. Atoms C13 at (x, y, z) and (1 − x, 1 − y, z), which are components of the cation lying across the twofold rotation axis along (1/2, 1/2, z), act as hydrogen-bond donors, respectively, to phosphonate atoms O4 in the anions at (0.25 + x, 0.75 − y, −0.25 + z) and (0.75 − x, 0.25 + y, −0.25 + z). These two anions lie, respectively, in the (100) sheets generated by the axes at x = 0.75 and 1/4, and propagation by the space group of this single soft hydrogen bond links all of the (100) sheets into a single framework.

Thus, a single type of hydrogen bond, namely O—H···O, gives rise to a one-dimensional substructure, the combination of two types of hydrogen bond, namely O—H···O and N—H···O, gives rise to a two-dimensional sub-structure, and the combination of three types of hydrogen bond, namely O—H···O, N—H···O and C—H···O, generates the entire three-dimensional structure. The anion substructure, in particular, differs from those found in the corresponding salts formed from 4,4'-bipyridyl and 1,2-bis(4-pyridyl)ethane.

In contrast to (I), the simple salt 4,4'-trimethylenedipyridinium dinitrate, (II) (Lee et al., 2003), whose constitution precludes the formation of O—H···O hydrogen bonds, contains just three-component aggregates containing a pair of N—H···O hydrogen bonds, but with no significant C—H···O hydrogen bonds between these aggregates. On the other hand, there are strong electrostatic interactions between adjacent pyridinium rings and nitrate ions, whose planes are nearly parallel to one another. Note also the contrast between (II) and the hydrated nitrate, (III), formed by 1,2-bis(4-pyridyl)ethane, which contains a monoprotonated diamine (Almeida Paz et al., 2003). In (III), the cations are linked into chains by N—H···N hydrogen bonds, and the nitrate ions and water molecules form hydrogen-bonded layers, but there are no hard hydrogen bonds between cations and anions.

S2. Experimental

Stoichiometric quantities of 4,4'-trimethylenedipyridine and carboxymethylphosphonic acid (both purchased from Aldrich) were dissolved separately in methanol. The solutions were mixed and the mixture was set aside to crystallize, providing analytically pure (I). Analysis found: C 42.8, H 5.2, N 5.8%; C₁₇H₂₄N₂O₁₀P₂ requires: C 42.7, H 5.1, N 5.9%. Crystals suitable for single-crystal X-ray diffraction were selected directly from the analytical sample.

S3. Refinement

Crystals of (I) are orthorhombic and the space group Fdd2 was assigned uniquely from the systematic absences. All H atoms were located from difference maps and were subsequently treated as riding atoms, with C—H distances of 0.95 (aromatic) or 0.99 Å (CH₂), N—-H distances of 0.88 Å, and O—H 0.84 Å. The correct orientation of the structure with respect to the polar axis was established using the Flack (1983) parameter.

Computing details

Data collection: KappaCCD Server Software (Nonius, 1997); cell refinement: DENZO–SMN (Otwinowski & Minor, 1997); data reduction: DENZO–SMN; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON (Spek, 2003); software used to prepare material for publication: SHELXL97 and PRPKAPPA (Ferguson, 1999).

Figures

	Fig. 1. The independent components of (I), showing the atom-labelling scheme. Displacement ellipsoids have been drawn at the 30% probability level.
	Fig. 2. Part of the crystal structure of (I), showing the formation of a chain of edge-fused R^33(16) rings containing anions only. For clarity, H atoms bonded to C atoms, and the unit-cell box, have been omitted. Atoms marked with an asterisk (*), hash (#), dollar sign ($) or ampersand (&) are at the symmetry positions (x, y, 1 + z), (x, y, −1 + z), (1 − x, 0.5 − y, −0.5 + z) and (1 − x, 0.5 − y, 0.5 + z), respectively.
	Fig. 3. Stereoview of part of the crystal structure of (I), showing the formation via the hard hydrogen bonds of the (100) sheet at x = 0.5.
	Fig. 4. Stereoview of part of the crystal structure of (I), showing the linking of the (100) sheets into a single framework by a single C—H···O hydrogen bond.

4,4'-Trimethylenedipyridinium bis[carboxymethylphosphonate(1-)]

Crystal data

C13H16N2^2+·2C2H4O5P^−	F(000) = 2000
Mr = 478.32	Dx = 1.470 Mg m^−3
Orthorhombic, Fdd2	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: F 2 -2d	Cell parameters from 2418 reflections
a = 27.366 (2) Å	θ = 2.9–27.5°
b = 32.347 (2) Å	µ = 0.26 mm^−1
c = 4.8818 (3) Å	T = 150 K
V = 4321.4 (5) Å^3	Needle, colourless
Z = 8	0.16 × 0.06 × 0.06 mm

Data collection

Nonius KappaCCD diffractometer	2418 independent reflections
Radiation source: fine-focus sealed X-ray tube	1864 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.084
ϕ scans, and ω scans with κ offsets	θmax = 27.5°, θmin = 2.9°
Absorption correction: multi-scan (DENZO–SMN; Otwinowski & Minor, 1997)	h = −35→34
Tmin = 0.886, Tmax = 0.990	k = −37→42
7640 measured reflections	l = −6→6

Refinement

Refinement on F^2	Hydrogen site location: inferred from neighbouring sites
Least-squares matrix: full	H-atom parameters constrained
R[F^2 > 2σ(F^2)] = 0.044	w = 1/[σ^2(Fo^2) + (0.0427P)^2 + 0.6064P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.103	(Δ/σ)max < 0.001
S = 1.05	Δρmax = 0.30 e Å^−3
2418 reflections	Δρmin = −0.24 e Å^−3
144 parameters	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
1 restraint	Extinction coefficient: 0.00136 (19)
Primary atom site location: structure-invariant direct methods	Absolute structure: Flack (1983), 1029 Friedel pairs
Secondary atom site location: difference Fourier map	Absolute structure parameter: 0.06 (13)

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
P1	0.39420 (3)	0.27700 (2)	0.87865 (14)	0.0252 (2)
O1	0.49101 (8)	0.21961 (7)	0.7812 (5)	0.0347 (5)
O2	0.43769 (8)	0.18466 (7)	0.5217 (5)	0.0380 (6)
O3	0.35287 (7)	0.28358 (7)	1.0967 (4)	0.0308 (5)
O4	0.37252 (7)	0.28622 (7)	0.6044 (4)	0.0328 (5)
O5	0.43899 (7)	0.30201 (6)	0.9515 (4)	0.0293 (5)
C1	0.44687 (11)	0.20679 (9)	0.7158 (6)	0.0285 (7)
C2	0.40885 (11)	0.22249 (9)	0.9112 (7)	0.0289 (7)
N1	0.46225 (10)	0.35877 (7)	0.5904 (6)	0.0348 (6)
C12	0.50721 (11)	0.37515 (9)	0.5786 (7)	0.0326 (7)
C13	0.51670 (11)	0.40816 (9)	0.4078 (6)	0.0301 (7)
C14	0.47936 (10)	0.42485 (9)	0.2468 (6)	0.0261 (7)
C15	0.43317 (11)	0.40659 (9)	0.2642 (7)	0.0318 (7)
C16	0.42598 (11)	0.37327 (10)	0.4362 (6)	0.0368 (8)
C17	0.48856 (11)	0.46211 (8)	0.0728 (6)	0.0278 (7)
C18	0.5000	0.5000	0.2493 (9)	0.0280 (9)
H1	0.5112	0.2108	0.6655	0.052*
H3	0.3646	0.2807	1.2546	0.046*
H2A	0.4203	0.2173	1.1005	0.035*
H2B	0.3785	0.2063	0.8839	0.035*
H1A	0.4566	0.3380	0.7024	0.042*
H12	0.5326	0.3640	0.6884	0.039*
H13	0.5487	0.4196	0.3996	0.036*
H15	0.4068	0.4171	0.1581	0.038*
H16	0.3947	0.3605	0.4447	0.044*
H17A	0.4594	0.4678	−0.0411	0.033*
H17B	0.5164	0.4566	−0.0516	0.033*
H18A	0.4716	0.5061	0.3686	0.034*	0.50
H18B	0.5284	0.4939	0.3686	0.034*	0.50

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
P1	0.0222 (4)	0.0300 (4)	0.0234 (4)	0.0018 (3)	0.0007 (3)	0.0006 (3)
O1	0.0281 (12)	0.0411 (13)	0.0350 (13)	0.0010 (10)	0.0050 (10)	−0.0066 (10)
O2	0.0375 (13)	0.0375 (12)	0.0389 (13)	0.0023 (10)	0.0009 (11)	−0.0095 (11)
O3	0.0250 (10)	0.0444 (12)	0.0229 (11)	0.0042 (10)	−0.0005 (9)	−0.0015 (10)
O4	0.0300 (11)	0.0446 (12)	0.0237 (11)	0.0066 (9)	−0.0014 (10)	0.0031 (10)
O5	0.0239 (10)	0.0276 (11)	0.0365 (13)	−0.0014 (9)	−0.0023 (9)	0.0016 (9)
C1	0.0283 (16)	0.0267 (15)	0.0306 (17)	0.0012 (13)	−0.0009 (13)	0.0041 (13)
C2	0.0320 (15)	0.0254 (14)	0.0293 (17)	−0.0035 (13)	0.0080 (14)	0.0012 (12)
N1	0.0449 (16)	0.0236 (13)	0.0360 (15)	−0.0021 (12)	0.0051 (14)	0.0022 (12)
C12	0.0358 (17)	0.0260 (15)	0.0361 (18)	0.0028 (13)	−0.0002 (14)	−0.0025 (14)
C13	0.0285 (14)	0.0256 (15)	0.0363 (18)	−0.0011 (12)	−0.0008 (15)	0.0005 (13)
C14	0.0312 (16)	0.0191 (15)	0.0281 (16)	0.0012 (12)	0.0001 (13)	−0.0036 (12)
C15	0.0280 (15)	0.0306 (16)	0.0369 (17)	−0.0013 (14)	−0.0014 (14)	−0.0014 (14)
C16	0.0320 (18)	0.0321 (17)	0.046 (2)	−0.0069 (14)	0.0079 (16)	−0.0017 (14)
C17	0.0268 (16)	0.0228 (15)	0.0338 (18)	−0.0043 (12)	−0.0017 (13)	0.0022 (12)
C18	0.031 (2)	0.022 (2)	0.031 (2)	0.0005 (18)	0.000	0.000

Geometric parameters (Å, º)

P1—O3	1.568 (2)	C12—H12	0.95
P1—O4	1.495 (2)	C13—C14	1.398 (4)
P1—O5	1.511 (2)	C13—H13	0.95
P1—C2	1.815 (3)	C14—C15	1.398 (4)
C1—O1	1.317 (4)	C14—C17	1.496 (4)
O1—H1	0.84	C15—C16	1.380 (4)
C1—O2	1.214 (4)	C15—H15	0.95
O3—H3	0.84	C16—H16	0.95
C1—C2	1.500 (4)	C17—C18	1.531 (4)
C2—H2A	0.99	C17—H17A	0.99
C2—H2B	0.99	C17—H17B	0.99
N1—C16	1.331 (4)	C18—C17^i	1.531 (4)
N1—C12	1.341 (4)	C18—H18A	0.99
N1—H1A	0.88	C18—H18B	0.99
C12—C13	1.379 (4)
O4—P1—O5	115.20 (12)	C12—C13—H13	120.0
O4—P1—O3	107.15 (12)	C14—C13—H13	120.0
O5—P1—O3	110.65 (11)	C13—C14—C15	117.6 (3)
O4—P1—C2	111.10 (14)	C13—C14—C17	120.5 (3)
O5—P1—C2	108.68 (13)	C15—C14—C17	121.8 (3)
O3—P1—C2	103.41 (13)	C16—C15—C14	119.7 (3)
C1—O1—H1	109.5	C16—C15—H15	120.1
P1—O3—H3	109.5	C14—C15—H15	120.1
O2—C1—O1	124.4 (3)	N1—C16—C15	120.8 (3)
O2—C1—C2	123.6 (3)	N1—C16—H16	119.6
O1—C1—C2	112.1 (3)	C15—C16—H16	119.6
C1—C2—P1	115.3 (2)	C14—C17—C18	111.1 (2)
C1—C2—H2A	108.5	C14—C17—H17A	109.4
P1—C2—H2A	108.5	C18—C17—H17A	109.4
C1—C2—H2B	108.5	C14—C17—H17B	109.4
P1—C2—H2B	108.5	C18—C17—H17B	109.4
H2A—C2—H2B	107.5	H17A—C17—H17B	108.0
C16—N1—C12	121.4 (3)	C17^i—C18—C17	111.5 (3)
C16—N1—H1A	119.3	C17^i—C18—H18A	109.3
C12—N1—H1A	119.3	C17—C18—H18A	109.3
N1—C12—C13	120.3 (3)	C17^i—C18—H18B	109.3
N1—C12—H12	119.9	C17—C18—H18B	109.3
C13—C12—H12	119.8	H18A—C18—H18B	108.0
C12—C13—C14	120.1 (3)
C13—C14—C17—C18	−65.0 (3)	C14—C17—C18—C17^i	177.8 (2)

Symmetry code: (i) −x+1, −y+1, z.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1—H1···O5^ii	0.84	1.77	2.598 (3)	170
O3—H3···O4^iii	0.84	1.73	2.537 (3)	160
N1—H1A···O5	0.88	1.75	2.624 (3)	171
C13—H13···O4^iv	0.95	2.48	3.419 (4)	167

Symmetry codes: (ii) −x+1, −y+1/2, z−1/2; (iii) x, y, z+1; (iv) x+1/4, −y+3/4, z−1/4.