Poly[diaqua-μ₄-biphenyl-4,4′-dicarboxyl­ato-magnesium(II)]

The solvothermal reaction of magnesium nitrate with bi­phenyl-4,4′-dicarboxylic acid in N,N-dimethyl­formamide and water leads to the formation of crystals of the title complex, [Mg(C₁₄H₈O₄)(H₂O)₂]_n. In the crystal structure, the Mg cations are coordinated by six O atoms from two water mol­ecules and four symmetry-related biphenyl-4,4′-dicarboxyl­ate anions within slightly distorted octa­hedra. The Mg cations are located on a center of inversion, the biphenyl-4,4′-dicarboxyl­ate anions around a twofold rotation axis and the water mol­ecule in a general position. The Mg cations are linked by the anions into a three-dimensional framework.

Key indicators

• Single-crystal X-ray study
• T = 295 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.041
• wR factor = 0.106
• Data-to-parameter ratio = 16.4

checkCIF/PLATON results

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Alert level C
            Value of measurement temperature given =   295.000
            Value of melting point given =     0.000
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....       2.13
PLAT041_ALERT_1_C Calc. and Rep. SumFormula Strings    Differ ....          ?
PLAT045_ALERT_1_C Calculated and Reported Z Differ by ............       0.50 Ratio
PLAT048_ALERT_1_C MoietyFormula Not Given ........................          ?
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?

Alert level G
PLAT720_ALERT_4_G Number of Unusual/Non-Standard Labels ..........          2

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

   3 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
   0 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

The synthesis of coordination polymers, or so-called metal-organic frameworks (MOF), has been a subject of intense research owing to their interesting structural chemistry and potential applications in gas storage, separation, catalysis, magnetism, luminescence. A large number of these compounds have been synthesized by solvothermal reactions with organic carboxyl acids (Kitagawa et al., 2004). Here we report on the new metal organic framework bis(aqua)-biphenyl-4,4'-dicarboxylate magnesium (II). In the crystal structure the Mg cations are sorrounded by two O atoms from two symmetry related water molecules and four O atoms of four symmetry related anions (Fig. 1). The coordination polyhedron around the Mg cations can be described as a slightly distorted octahedron. The Mg cations are linked via the anions into a three-dimensional network (Fig. 2).

Related literature

For related structures, see: Kitagawa et al. (2004). Please resupply Fig. 2; the existing file has been corrupted.

S2. Experimental

The reaction was carried out under solvothermal conditions in a teflon-lined autoclav with an inner volume of 23 ml. A single-phase product consisting of transparent colorless crystals was obtained by heating a mixture of Mg(NO₃)₂˙6H₂O, (0.1281 g, 0.5 mmol), biphenyl-4,4'-dicarboxylic acid (C₁₄H₁₀O₄, 0.0290 g, 0.125 mmol), N,N-dimethylformamide (10.0 ml), and H₂O (2.0 ml)at 423 K for 2 d followed by slow cooling at 6 K/h to room temperature.

S3. Refinement

The C—H H atoms were positioned with idealized geometry and were refined isotropic using a riding model with C—H = 0.93 Å and U_iso(H) = 1.2U_eq(C). The H atoms at the water molecule were found in difference map and were refined with varying coordinates isotropic.

Computing details

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. Crystal structure of the title compound with labeling and displacement ellipsoids drawn at the 50% probability level. [symmetry codes: (i) -x + 2,-y + 1,-z; (ii) -x + 3/2,y - 1/2,z; (iii) x + 1/2,-y + 3/2,-z; (iv) -x + 2,y,-z + 1/2.].
	Fig. 2. Crystal structure of the title compound with view along the a axis.

Poly[diaqua-µ₄-biphenyl-4,4'-dicarboxylato-magnesium(II)]

Crystal data

[Mg(C14H8O4)(H2O)2]	Dx = 1.553 Mg m^−3
Mr = 150.27	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Pbcn	Cell parameters from 1007 reflections
a = 6.5913 (10) Å	θ = 3.1–25.2°
b = 7.2900 (9) Å	µ = 0.16 mm^−1
c = 26.759 (4) Å	T = 295 K
V = 1285.8 (3) Å^3	Lamellar, colorless
Z = 8	0.15 × 0.10 × 0.05 mm
F(000) = 624

Data collection

Bruker APEXII CCD diffractometer	1589 independent reflections
Radiation source: fine-focus sealed tube	1048 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.048
ϕ and ω scans	θmax = 28.4°, θmin = 1.5°
Absorption correction: multi-scan (SADABS; Bruker, 2007)	h = −7→8
Tmin = 0.976, Tmax = 0.995	k = −9→9
5950 measured reflections	l = −22→35

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)] = 0.041	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.106	H-atom parameters constrained
S = 1.02	w = 1/[σ^2(Fo^2) + (0.0448P)^2 + 0.3401P] where P = (Fo^2 + 2Fc^2)/3
1589 reflections	(Δ/σ)max < 0.001
97 parameters	Δρmax = 0.30 e Å^−3
0 restraints	Δρmin = −0.30 e Å^−3

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
Mg1	1.0000	0.5000	0.0000	0.0159 (2)
C1	0.7888 (3)	0.7850 (2)	0.06884 (7)	0.0162 (4)
C2	0.8503 (3)	0.7715 (3)	0.12262 (7)	0.0184 (4)
C3	0.7124 (3)	0.8132 (3)	0.16000 (7)	0.0245 (5)
H3	0.5796	0.8440	0.1517	0.029*
C4	0.7715 (4)	0.8092 (3)	0.20963 (7)	0.0259 (5)
H4	0.6775	0.8380	0.2343	0.031*
C5	0.9691 (3)	0.7629 (3)	0.22334 (7)	0.0211 (5)
C6	1.1051 (3)	0.7183 (3)	0.18550 (7)	0.0261 (5)
H6	1.2372	0.6854	0.1938	0.031*
C7	1.0476 (3)	0.7220 (3)	0.13581 (8)	0.0242 (5)
H7	1.1409	0.6915	0.1111	0.029*
O1	0.9201 (2)	0.74253 (17)	0.03552 (5)	0.0194 (3)
O1W	0.7228 (2)	0.48848 (18)	−0.03619 (5)	0.0221 (3)
H1WA	0.6306	0.5799	−0.0412	0.080*
H1WB	0.6335	0.4082	−0.0293	0.080*
O2	0.6164 (2)	0.8454 (2)	0.05857 (5)	0.0233 (4)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Mg1	0.0166 (5)	0.0205 (4)	0.0107 (4)	0.0010 (4)	0.0010 (4)	−0.0006 (4)
C1	0.0195 (11)	0.0161 (9)	0.0129 (9)	0.0000 (8)	0.0000 (8)	0.0002 (7)
C2	0.0214 (12)	0.0218 (10)	0.0121 (9)	0.0017 (8)	−0.0020 (8)	0.0004 (8)
C3	0.0214 (12)	0.0352 (12)	0.0171 (10)	0.0075 (10)	−0.0001 (9)	0.0004 (9)
C4	0.0271 (13)	0.0388 (11)	0.0116 (9)	0.0057 (10)	0.0022 (9)	−0.0003 (9)
C5	0.0240 (12)	0.0272 (10)	0.0120 (10)	0.0006 (9)	−0.0017 (9)	−0.0002 (8)
C6	0.0202 (12)	0.0416 (12)	0.0166 (10)	0.0029 (10)	−0.0037 (9)	0.0012 (9)
C7	0.0216 (12)	0.0369 (12)	0.0141 (10)	0.0042 (10)	0.0010 (8)	−0.0005 (9)
O1	0.0221 (8)	0.0232 (7)	0.0129 (7)	0.0025 (6)	0.0012 (6)	−0.0015 (6)
O1W	0.0165 (8)	0.0279 (7)	0.0221 (7)	0.0001 (6)	−0.0011 (6)	0.0012 (6)
O2	0.0200 (8)	0.0346 (8)	0.0152 (7)	0.0065 (7)	−0.0015 (7)	0.0041 (6)

Geometric parameters (Å, º)

Mg1—O1W^i	2.0696 (14)	C3—H3	0.9300
Mg1—O1W	2.0696 (14)	C4—C5	1.395 (3)
Mg1—O1	2.0753 (12)	C4—H4	0.9300
Mg1—O1^i	2.0753 (12)	C5—C6	1.391 (3)
Mg1—O2^ii	2.0774 (13)	C5—C5^iv	1.484 (4)
Mg1—O2^iii	2.0774 (13)	C6—C7	1.383 (3)
C1—O2	1.249 (2)	C6—H6	0.9300
C1—O1	1.281 (2)	C7—H7	0.9300
C1—C2	1.498 (3)	O1W—H1WA	0.9119
C2—C3	1.385 (3)	O1W—H1WB	0.8502
C2—C7	1.395 (3)	O2—Mg1^v	2.0774 (13)
C3—C4	1.384 (3)
O1W^i—Mg1—O1W	180.00 (10)	C4—C3—C2	120.2 (2)
O1W^i—Mg1—O1	88.58 (5)	C4—C3—H3	119.9
O1W—Mg1—O1	91.42 (5)	C2—C3—H3	119.9
O1W^i—Mg1—O1^i	91.42 (5)	C3—C4—C5	121.3 (2)
O1W—Mg1—O1^i	88.58 (5)	C3—C4—H4	119.3
O1—Mg1—O1^i	180.00 (6)	C5—C4—H4	119.3
O1W^i—Mg1—O2^ii	89.72 (5)	C6—C5—C4	117.84 (18)
O1W—Mg1—O2^ii	90.28 (5)	C6—C5—C5^iv	121.5 (2)
O1—Mg1—O2^ii	91.31 (5)	C4—C5—C5^iv	120.6 (2)
O1^i—Mg1—O2^ii	88.69 (5)	C7—C6—C5	121.3 (2)
O1W^i—Mg1—O2^iii	90.28 (5)	C7—C6—H6	119.4
O1W—Mg1—O2^iii	89.72 (5)	C5—C6—H6	119.4
O1—Mg1—O2^iii	88.69 (5)	C6—C7—C2	120.2 (2)
O1^i—Mg1—O2^iii	91.31 (5)	C6—C7—H7	119.9
O2^ii—Mg1—O2^iii	180.00 (8)	C2—C7—H7	119.9
O2—C1—O1	123.14 (17)	C1—O1—Mg1	134.15 (12)
O2—C1—C2	118.73 (17)	Mg1—O1W—H1WA	128.9
O1—C1—C2	118.03 (17)	Mg1—O1W—H1WB	122.5
C3—C2—C7	119.06 (18)	H1WA—O1W—H1WB	94.2
C3—C2—C1	120.10 (18)	C1—O2—Mg1^v	133.89 (13)
C7—C2—C1	120.82 (18)

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