Pyridinium diaqua­bis­(methyl­enediphospho­nato-κ² O,O′)chromate(III) tetra­hydrate

Abstract

In the title complex, (C₅H₆N)[Cr(CH₄O₆P₂)₂(H₂O)₂]·4H₂O, the Cr^III atom, lying on an inversion centre, is coordinated by two bidentate methyl­ene diphospho­nate ligands and two water molecules in a distorted octa­hedral coordination geometry. The pyridinium cation is located on an inversion centre, with an N atom and a C atom sharing a position each at a half occupancy. A three-dimensional network is constructed by O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds between the pyridin­ium cation, complex anion and uncoordinated water mol­ecules.

Related literature

For general background to metal-organic frameworks with diphospho­nic acids, see: Barthelet et al. (2002 ▶). For related structures, see: Byun et al. (2006 ▶); Suh et al. (1997 ▶); Van der Merwe et al. (2009 ▶); Visser et al. (2010 ▶).

Experimental

Crystal data

• (C₅H₆N)[Cr(CH₄O₆P₂)₂(H₂O)₂]·4H₂O

• M _r = 588.17

• Triclinic,

• a = 7.206 (5) Å

• b = 7.485 (5) Å

• c = 10.984 (5) Å

• α = 107.085 (5)°

• β = 106.128 (5)°

• γ = 94.496 (5)°

• V = 535.7 (6) ų

• Z = 1

• Mo Kα radiation

• μ = 0.92 mm⁻¹

• T = 100 K

• 0.22 × 0.16 × 0.08 mm

Data collection

• Bruker APEXII CCD diffractometer

• Absorption correction: multi-scan (SADABS; (Bruker, 2001 ▶) T _min = 0.843, T _max = 0.931

• 8784 measured reflections

• 2632 independent reflections

• 2483 reflections with I > 2σ(I)

• R _int = 0.020

Refinement

• R[F ² > 2σ(F ²)] = 0.024

• wR(F ²) = 0.070

• S = 1.05

• 2632 reflections

• 179 parameters

• 16 restraints

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

• Δρ_max = 0.47 e Å⁻³

• Δρ_min = −0.62 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT-Plus (Bruker, 2007 ▶); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: DIAMOND (Brandenburg, 1999 ▶); software used to prepare material for publication: SHELXTL.

Supplementary Material

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Selected bond lengths (Å).

Cr1—O1	1.991 (4)
Cr1—O2	1.956 (4)
Cr1—O7	1.964 (4)

Table 2. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H4⋯O6i	0.97	2.49	3.346 (7)	147
C4—H4A⋯O9ii	0.93	2.16	2.93 (7)	140
N1—H1⋯O9ii	0.86	2.32	3.03 (5)	141
O1—H1A⋯O6i	0.80 (6)	1.83 (6)	2.634 (6)	176 (9)
O1—H1B⋯O4iii	0.83 (6)	1.87 (6)	2.704 (6)	177 (9)
O3—H3⋯O8iv	0.82	1.83	2.629 (6)	163
O5—H6⋯O4ii	0.83 (5)	1.80 (5)	2.619 (6)	175 (10)
O8—H7⋯O6v	0.83 (6)	1.86 (6)	2.687 (6)	171 (9)
O8—H8⋯O9	0.85 (7)	1.94 (8)	2.748 (7)	158 (11)
O9—H9A⋯O4	0.83 (6)	2.00 (6)	2.833 (6)	179 (10)
O9—H10⋯O8vi	0.84 (7)	1.99 (7)	2.820 (7)	174 (13)

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

supplementary crystallographic information

Comment

The title compound forms part of an ongoing study in our group involving methylene diphosphonate and its coordination to various metal cores. (Van der Merwe et al., 2009; Visser et al., 2010). Diphosphonic acids are useful for the synthesis of metal-organic frameworks exhibiting microporous properties (Barthelet et al., 2002).

The Cr^III ion in the title complex is in a distorted octahedral environment (Fig. 1), with Cr—O bond distances ranging from 1.956 (4) to 1.991 (4) Å (Table 1). All the bond distances and angles are well within the normal range (Byun et al., 2006; Suh et al., 1997). The pyridinium cation is located on an inversion centre and an N atom and a C atom share a position at a half occupancy for each atom. A three-dimensional network is provided by numerous hydrogen bonds between the pyridinium cation, complex anion and uncoordinated water molecules (Table 2).

Experimental

CrCl₃.6H₂O (0.092 g, 0.347 mmol) was dissolved in water (40 ml) and ammonium hydroxide was gradually added dropwise in order to precipitate Cr(III) hydroxide. Methylene diphosphonate (0.347 g, 2 mmol) was added to the Cr(OH)₃ and water (40 ml). The reaction solution was heated on an oil bath for 5 h at 100°C, after which pyridine (10 ml) was added to the solution. Boiling H₂O (30 ml) was added and the solution was centrifuged. Green crystals of the title compound crystallized from the filtrate after several days.

Refinement

C-bound H atoms were positioned geometrically and refined as riding atoms, with C—H = 0.97 Å and U_iso(H) = 1.2U_eq(C). The H atoms attached to hydroxy groups and water molecules were located on a difference Fourier map and refined isotropically except H3, which was refined as riding, with O3—H3 = 0.82 Å and U_iso(H3) = 1.5U_eq(O3). A 50% positional disorder was assigned to N1 and C4, which share a position of the pyridine ring, as this provided the best fit of the data. Short C—C bond interactions, probably due to this disorder, are observed for the pyridinium cation.

Figures

Fig. 1.

Molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. [Symmetry code: (i) 1-x, 1-y, 1-z.]

Crystal data

(C5H6N)[Cr(CH4O6P2)2(H2O)2]·4H2O	Z = 1
Mr = 588.17	F(000) = 303
Triclinic, P1	Dx = 1.823 Mg m−3
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 7.206 (5) Å	Cell parameters from 6300 reflections
b = 7.485 (5) Å	θ = 0.8–0.9°
c = 10.984 (5) Å	µ = 0.92 mm−1
α = 107.085 (5)°	T = 100 K
β = 106.128 (5)°	Cuboid, green
γ = 94.496 (5)°	0.22 × 0.16 × 0.08 mm
V = 535.7 (6) Å3

Data collection

Bruker APEXII CCD diffractometer	2483 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.020
Absorption correction: multi-scan (SADABS; (Bruker, 2001)	θmax = 28.3°, θmin = 4.1°
Tmin = 0.843, Tmax = 0.931	h = −9→9
8784 measured reflections	k = −9→6
2632 independent reflections	l = −14→14

Refinement

Refinement on F2	16 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F2 > 2σ(F2)] = 0.024	w = 1/[σ2(Fo2) + (0.0342P)2 + 0.4874P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.070	(Δ/σ)max < 0.001
S = 1.05	Δρmax = 0.47 e Å−3
2632 reflections	Δρmin = −0.62 e Å−3
179 parameters

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Cr1	0.5000	0.5000	0.5000	0.0082 (3)
P2	0.2173 (2)	0.79359 (19)	0.41325 (14)	0.0086 (4)
P1	0.29362 (19)	0.7622 (2)	0.69142 (14)	0.0085 (4)
O2	0.4491 (6)	0.6457 (6)	0.6635 (4)	0.0110 (8)
O5	−0.0069 (6)	0.7069 (6)	0.3539 (4)	0.0128 (8)
O3	0.3700 (6)	0.8943 (6)	0.8418 (4)	0.0134 (8)
H3	0.4774	0.9569	0.8570	0.020*
O7	0.3373 (6)	0.6353 (6)	0.3947 (4)	0.0113 (8)
O9	−0.0373 (8)	0.7358 (7)	0.8942 (5)	0.0235 (10)
O1	0.7325 (6)	0.6953 (6)	0.5401 (4)	0.0121 (8)
C1	0.2683 (8)	0.9145 (8)	0.5903 (6)	0.0108 (10)
H4	0.3885	1.0063	0.6226	0.013*
H5	0.1633	0.9841	0.6027	0.013*
O4	0.0957 (6)	0.6494 (6)	0.6673 (4)	0.0118 (8)
O8	0.2601 (7)	0.9720 (7)	1.1133 (5)	0.0198 (10)
N1	0.381 (7)	0.479 (8)	0.070 (5)	0.028 (12)	0.50
H1	0.3025	0.4691	0.1145	0.034*	0.50
C4	0.381 (8)	0.466 (10)	0.078 (5)	0.024 (10)	0.50
H4A	0.3051	0.4405	0.1294	0.029*	0.50
C3	0.5612 (13)	0.5896 (11)	0.1367 (8)	0.0312 (17)
H3A	0.6025	0.6454	0.2295	0.037*
C2	0.3206 (12)	0.3837 (11)	−0.0627 (8)	0.0322 (17)
H2	0.2008	0.3014	−0.1034	0.039*
O6	0.2543 (6)	0.9385 (6)	0.3492 (4)	0.0133 (8)
H8	0.193 (16)	0.882 (13)	1.042 (9)	0.06 (3)*
H7	0.262 (14)	0.950 (13)	1.184 (7)	0.03 (2)*
H1B	0.844 (10)	0.677 (12)	0.577 (8)	0.03 (2)*
H1A	0.731 (13)	0.806 (9)	0.573 (8)	0.025*
H6	−0.032 (11)	0.597 (8)	0.352 (9)	0.03 (3)*
H9A	0.002 (13)	0.710 (13)	0.828 (8)	0.03 (2)*
H10	−0.110 (17)	0.817 (16)	0.888 (14)	0.07 (4)*

Atomic displacement parameters (Ų)

	U11	U22	U33	U12	U13	U23
Cr1	0.0067 (6)	0.0081 (6)	0.0107 (6)	0.0020 (4)	0.0035 (4)	0.0035 (5)
P2	0.0072 (6)	0.0076 (7)	0.0120 (7)	0.0015 (5)	0.0031 (5)	0.0042 (5)
P1	0.0068 (6)	0.0084 (7)	0.0103 (7)	0.0011 (5)	0.0032 (5)	0.0025 (5)
O2	0.0103 (18)	0.0121 (19)	0.0119 (19)	0.0050 (15)	0.0043 (15)	0.0042 (15)
O5	0.0077 (18)	0.011 (2)	0.019 (2)	0.0004 (15)	0.0019 (15)	0.0053 (16)
O3	0.0110 (18)	0.013 (2)	0.0126 (19)	−0.0004 (15)	0.0036 (15)	0.0006 (16)
O7	0.0103 (18)	0.0116 (19)	0.0136 (19)	0.0046 (15)	0.0047 (15)	0.0048 (15)
O9	0.029 (3)	0.024 (3)	0.021 (2)	0.004 (2)	0.014 (2)	0.007 (2)
O1	0.0082 (18)	0.0088 (19)	0.019 (2)	0.0013 (15)	0.0034 (16)	0.0043 (16)
C1	0.010 (2)	0.008 (2)	0.013 (3)	0.0014 (19)	0.003 (2)	0.003 (2)
O4	0.0085 (18)	0.0114 (19)	0.0153 (19)	0.0000 (14)	0.0039 (15)	0.0043 (15)
O8	0.018 (2)	0.026 (2)	0.013 (2)	−0.0028 (18)	0.0032 (17)	0.0052 (19)
N1	0.04 (2)	0.028 (18)	0.033 (19)	0.019 (13)	0.019 (16)	0.023 (13)
C4	0.026 (18)	0.019 (15)	0.018 (15)	−0.001 (12)	−0.008 (12)	0.008 (13)
C3	0.042 (5)	0.020 (3)	0.021 (3)	0.007 (3)	−0.004 (3)	0.006 (3)
C2	0.033 (4)	0.023 (4)	0.029 (4)	0.000 (3)	−0.008 (3)	0.009 (3)
O6	0.0148 (19)	0.0108 (19)	0.016 (2)	0.0016 (15)	0.0053 (16)	0.0073 (16)

Geometric parameters (Å, °)

Cr1—O1	1.991 (4)	O1—H1B	0.83 (6)
Cr1—O2	1.956 (4)	O1—H1A	0.80 (6)
Cr1—O7	1.964 (4)	C1—H4	0.9700
P2—O6	1.499 (4)	C1—H5	0.9700
P2—O7	1.519 (4)	O8—H8	0.85 (7)
P2—O5	1.568 (4)	O8—H7	0.83 (6)
P2—C1	1.804 (6)	N1—C2	1.34 (5)
P1—O4	1.512 (4)	N1—C3	1.36 (4)
P1—O4	1.512 (4)	N1—H1	0.8600
P1—O2	1.515 (4)	C4—C3	1.40 (5)
P1—O3	1.568 (4)	C4—C2	1.41 (5)
P1—C1	1.797 (6)	C4—H4A	0.9300
O5—H6	0.83 (5)	C3—C2i	1.371 (13)
O3—H3	0.8200	C3—H3A	0.9300
O9—H9A	0.83 (6)	C2—C3i	1.371 (13)
O9—H10	0.84 (7)	C2—H2	0.9300
O2ii—Cr1—O2	180.00 (15)	P2—O5—H6	114 (5)
O2ii—Cr1—O7	88.35 (17)	P1—O3—H3	109.5
O2—Cr1—O7	91.65 (17)	P2—O7—Cr1	140.0 (3)
O2ii—Cr1—O7ii	91.65 (17)	H9A—O9—H10	108 (10)
O2—Cr1—O7ii	88.35 (17)	Cr1—O1—H1B	119 (6)
O7—Cr1—O7ii	180.0 (2)	Cr1—O1—H1A	120 (6)
O2ii—Cr1—O1ii	90.51 (17)	H1B—O1—H1A	107 (9)
O2—Cr1—O1ii	89.49 (17)	P1—C1—P2	114.8 (3)
O7—Cr1—O1ii	90.81 (18)	P1—C1—H4	108.6
O7ii—Cr1—O1ii	89.19 (18)	P2—C1—H4	108.6
O2ii—Cr1—O1	89.49 (17)	P1—C1—H5	108.6
O2—Cr1—O1	90.51 (17)	P2—C1—H5	108.6
O7—Cr1—O1	89.19 (18)	H4—C1—H5	107.5
O7ii—Cr1—O1	90.81 (18)	H8—O8—H7	114 (10)
O1ii—Cr1—O1	180.0 (3)	C2—N1—C3	123 (4)
O6—P2—O7	114.8 (2)	C2—N1—H1	118.3
O6—P2—O5	107.8 (2)	C3—N1—H1	118.3
O7—P2—O5	109.7 (2)	C3—C4—C2	116 (5)
O6—P2—C1	108.2 (3)	C3—C4—H4A	122.1
O7—P2—C1	109.0 (2)	C2—C4—H4A	122.1
O5—P2—C1	107.1 (2)	N1—C3—C2i	118 (2)
O4—P1—O2	115.5 (2)	C2i—C3—C4	122 (3)
O4—P1—O2	115.5 (2)	N1—C3—H3A	121.1
O4—P1—O3	107.9 (2)	C2i—C3—H3A	121.1
O4—P1—O3	107.9 (2)	C4—C3—H3A	116.7
O2—P1—O3	108.6 (2)	N1—C2—C3i	119 (2)
O4—P1—C1	110.1 (2)	C3i—C2—C4	122 (2)
O4—P1—C1	110.1 (2)	N1—C2—H2	120.7
O2—P1—C1	107.6 (2)	C3i—C2—H2	120.7
O3—P1—C1	106.9 (3)	C4—C2—H2	117.1
P1—O2—Cr1	134.1 (2)

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

Hydrogen-bond geometry (Å, °)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H4···O6iii	0.97	2.49	3.346 (7)	147
C4—H4A···O9iv	0.93	2.16	2.93 (7)	140
N1—H1···O9iv	0.86	2.32	3.03 (5)	141
O1—H1A···O6iii	0.80 (6)	1.83 (6)	2.634 (6)	176 (9)
O1—H1B···O4v	0.83 (6)	1.87 (6)	2.704 (6)	177 (9)
O3—H3···O8vi	0.82	1.83	2.629 (6)	163
O5—H6···O4iv	0.83 (5)	1.80 (5)	2.619 (6)	175 (10)
O8—H7···O6vii	0.83 (6)	1.86 (6)	2.687 (6)	171 (9)
O8—H8···O9	0.85 (7)	1.94 (8)	2.748 (7)	158 (11)
O9—H9A···O4	0.83 (6)	2.00 (6)	2.833 (6)	179 (10)
O9—H10···O8viii	0.84 (7)	1.99 (7)	2.820 (7)	174 (13)

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