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Acta Cryst. (2013). E69, m17-m18    [ doi:10.1107/S1600536812049434 ]

Aqua(4-cyanopyridine-[kappa]N4)(5,10,15,20-tetraphenylporphyrinato-[kappa]4N)magnesium

K. Ezzayani, M. S. Belkhiria, S. Najmudin, C. Bonifácio and H. Nasri

Abstract top

In the title complex, [Mg(C44H28N4)(C6H4N2)(H2O)], the Mg2+ cation is octahedrally coordinated and lies on an inversion center with the axially located 4-cyanopyridine and aqua ligands exhibiting 50% substitutional disorder. The cyano-bound 4-cyanopyridine molecule also is disordered across the inversion centre. The four N atoms of the pyrrole rings of the dianionic 5,10,15,20-tetraphenylporphyrin ligand occupy the equatorial sites of the octahedron [Mg-N = 2.0552 (10) and 2.0678 (11) Å] and the axial Mg-(N,O) bond length is 2.3798 (12) Å. The crystal packing is stabilized by weak intermolecular C-H...[pi] interactions.

Comment top

The majority of the reported metalloporphyrin structures involve metals from the first-row transition series. However, the structures of magnesium porphyrins are also of interest because of their relationship to chlorophyll. but the Cambridge Structural Database (CSD; Allen, 2002) contains only 24 structures of these. In order to gain more insight into the geometry of the latter species, we report herein the crystal structure of the title complex, [Mg(TPP)(4-CNpy)(H2O)] (where TPP is the 5,10,15,20-tetraphenylporphyrin dianion and 4-CNpy is 4-cyanopyridine).

In the title complex the Mg cation is octahedrally coordinated and lies on an inversion center with the axially-located 4-cyanopyridine and aqua ligands having occupancy factors of 0.5. The atoms of these disordered ligands are divided in two parts: in part 1, the fragment containing the atoms N3, C23, C24, C25A and C26A and in part 2, the atoms O1, N4, C25B and C26B, related by the symmetry code (i) -x, -y+1, -z+1. The 4-cyanopyridine ligand also has inversion symmetry with 50% occupancy [symmetry code (ii): -x+1, -y, -z+1] (Fig. 1). The average equatorial Mg—N(pyrrole) bond distance [2.062 (1) Å] is normal for Mg–porphyrin complexes. The Mg—O(H2O) bond length [2.3798 (12)Å] is longer than that found in the related complex [Mg(TPP)(H2O)] (2.012 (6) Å) (Choon et al., 1986) but is shorter than the one reported for the non-porphyrin complex catena-[diaquatetrakis(µ4-oxalato)-tris(µ2-oxalato)- dimagnesium-dipotassium-diuranium(IV) nonahydrate clathrate] [2.747 (5) Å] (Imaz et al., 2005).

The axial Mg—N(4-CNpy) bond length [2.3798 (12) Å] is longer than that found in the [Mg(TPP)][TCNQF4] complex [2.266 (2) Å] (where TCNQF4 is 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane) (Hibbs et al., 2003), but is within the range of 2.152 (2)–2.57 (1) Å found for several magnesium-nitrile non-porphyrin complexes in the CSD [refcodes FEGQAJ (Etkin et al., 1998) and SISWUN (Yang et al., 2008) (Allen, 2002).

The crystal structure resembles a one-dimensional coordination polymer where two [Mg(TPP)] moieties are linked by statistically 50% disordered 4-cyanopyridine and H2O ligands. The crystal packing of the title compound is stabilized by weak C—H···π intermolecular interactions involving Cg pyrrole and phenyl rings (Table 1 and Fig. 2).

Related literature top

For general background to magnesium porphyrin species and their applications, see: Ghosh et al. (2010). For the synthesis of the [Mg(TPP)(H2O)] complex, see: Timkovich & Tulinsky (1969). For related structures, see: Choon et al. (1986); Imaz et al. (2005); Hibbs et al. (2003); Etkin et al. (1998); Yang et al. (2008). For a description of the Cambridge Structural Database, see: Allen (2002).

Experimental top

To a solution of [Mg(TPP)(H2O)] (Timkovich & Tulinsky, 1969) (15 mg, 0.022 mmol) in chlorobenzene (10 ml) was added an excess of 4-cyanopyridine (50 mg, 0.480 mmol). The reaction mixture was stirred at room temperature and at the end of the reaction, the color of the solution gradually changed from purple to blue–purple. Crystals of the title complex were obtained by diffusion of n-hexane through the chlorobenzene solution.

Refinement top

The H atoms of the statistically disordered aqua ligand were not consideredted. and all H atoms attached to C atoms were fixed geometrically and treated as riding with C—H = 0.93 Å and with Uiso(H) = 1.2Ueq(C). The H atoms of the water molecule were not located

Computing details top

Data collection: APEX2 (Bruker, 2007); cell refinement: SAINT (Bruker, 2007); data reduction: SAINT (Bruker, 2007); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and ORTEP-3 for Windows (Farrugia, 2012); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. A view of the structure of the complex [Mg(C44H28N4)(C6H4N2)(H2O)] showing the atom numbering scheme. Displacement ellipsoids are drawn at the 40% level. The H atoms have been omitted for clarity. For symmetry codes: (i) -x, -y + 1, -z + 1; (ii) (i) -x + 1, -y, -z + 1.
[Figure 2] Fig. 2. Part of the crystal structure showing weak C—H······π intermolecular interactions.
Aqua(4-cyanopyridine-κN4)(5,10,15,20-tetraphenylporphyrinato- κ4N)magnesium top
Crystal data top
[Mg(C44H28N4)(C6H4N2)(H2O)]Z = 1
Mr = 757.13F(000) = 394.0
Triclinic, P1Dx = 1.293 Mg m−3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 8.9080 (3) ÅCell parameters from 6453 reflections
b = 10.7550 (4) Åθ = 2.7–27.9°
c = 11.9530 (6) ŵ = 0.09 mm−1
α = 63.446 (1)°T = 296 K
β = 89.364 (2)°Block, purple
γ = 73.408 (1)°0.48 × 0.40 × 0.24 mm
V = 972.60 (7) Å3
Data collection top
Bruker APEXII CCD
diffractometer		3792 independent reflections
Radiation source: fine-focus sealed tube3307 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.023
φ and ω scansθmax = 26.0°, θmin = 1.9°
Absorption correction: multi-scan
(SADABS; Bruker, 2007)		h = −8→10
Tmin = 0.955, Tmax = 0.978k = −13→13
11765 measured reflectionsl = −14→14
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.103H-atom parameters constrained
S = 1.07 w = 1/[σ2(Fo2) + (0.0446P)2 + 0.2998P]
where P = (Fo2 + 2Fc2)/3
3792 reflections(Δ/σ)max = 0.001
268 parametersΔρmax = 0.22 e Å−3
0 restraintsΔρmin = −0.54 e Å−3
Crystal data top
[Mg(C44H28N4)(C6H4N2)(H2O)]γ = 73.408 (1)°
Mr = 757.13V = 972.60 (7) Å3
Triclinic, P1Z = 1
a = 8.9080 (3) ÅMo Kα radiation
b = 10.7550 (4) ŵ = 0.09 mm−1
c = 11.9530 (6) ÅT = 296 K
α = 63.446 (1)°0.48 × 0.40 × 0.24 mm
β = 89.364 (2)°
Data collection top
Bruker APEXII CCD
diffractometer		3792 independent reflections
Absorption correction: multi-scan
(SADABS; Bruker, 2007)		3307 reflections with I > 2σ(I)
Tmin = 0.955, Tmax = 0.978Rint = 0.023
11765 measured reflectionsθmax = 26.0°
Refinement top
R[F2 > 2σ(F2)] = 0.039H-atom parameters constrained
wR(F2) = 0.103Δρmax = 0.22 e Å−3
S = 1.07Δρmin = −0.54 e Å−3
3792 reflectionsAbsolute structure: ?
268 parametersFlack parameter: ?
0 restraintsRogers parameter: ?
Special details top

Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 (Å2) top
xyzUiso*/UeqOcc. (<1)
Mg0.00000.50000.50000.0558 (3)
N10.12116 (13)0.31528 (11)0.66326 (11)0.0307 (3)
N2−0.15077 (13)0.39306 (11)0.48540 (10)0.0289 (2)
C10.25095 (15)0.29941 (14)0.73443 (12)0.0291 (3)
C20.30581 (17)0.15246 (14)0.83701 (13)0.0327 (3)
H20.39200.11390.89890.039*
C30.20800 (17)0.08127 (14)0.82614 (13)0.0320 (3)
H30.2143−0.01540.87930.038*
C40.09273 (15)0.18314 (13)0.71703 (12)0.0286 (3)
C5−0.02834 (15)0.15157 (13)0.66983 (12)0.0279 (3)
C6−0.14087 (15)0.25020 (13)0.56257 (12)0.0284 (3)
C7−0.26537 (16)0.21639 (15)0.51694 (14)0.0336 (3)
H7−0.28490.12690.55260.040*
C8−0.34809 (16)0.33799 (15)0.41330 (14)0.0342 (3)
H8−0.43550.34850.36420.041*
C9−0.27529 (15)0.44944 (14)0.39274 (13)0.0292 (3)
C100.32299 (15)0.40857 (14)0.70979 (13)0.0294 (3)
C110.45965 (16)0.37258 (14)0.80258 (13)0.0312 (3)
C120.61223 (18)0.34910 (18)0.77378 (16)0.0457 (4)
H120.63190.35270.69600.055*
C130.7370 (2)0.32017 (19)0.85992 (19)0.0557 (5)
H130.83940.30470.83930.067*
C140.7102 (2)0.31430 (17)0.97470 (17)0.0544 (5)
H140.79380.29531.03210.065*
C150.5591 (3)0.3367 (2)1.00457 (16)0.0604 (5)
H150.54020.33221.08280.073*
C160.4342 (2)0.36610 (19)0.91893 (15)0.0484 (4)
H160.33210.38160.94010.058*
C17−0.03842 (15)−0.00131 (14)0.73710 (12)0.0286 (3)
C18−0.1134 (2)−0.04637 (17)0.84312 (16)0.0474 (4)
H18−0.15290.01670.87770.057*
C19−0.1303 (2)−0.18509 (18)0.89874 (17)0.0546 (5)
H19−0.1808−0.21430.97030.065*
C20−0.07258 (19)−0.27960 (16)0.84860 (15)0.0423 (4)
H20−0.0866−0.37140.88460.051*
C210.00540 (19)−0.23746 (15)0.74544 (14)0.0402 (3)
H210.0466−0.30150.71220.048*
C220.02310 (18)−0.09931 (15)0.69032 (13)0.0355 (3)
H220.0773−0.07210.62070.043*
N30.17377 (15)0.40333 (15)0.38534 (13)0.0541 (3)0.50
C230.2697 (3)0.2742 (3)0.4230 (3)0.0370 (6)0.50
C240.38443 (16)0.13429 (15)0.45960 (14)0.0406 (3)0.50
C25A0.43163 (19)0.04190 (18)0.58443 (17)0.0465 (4)0.50
H25A0.38590.06920.64370.056*0.50
C26A0.45348 (19)0.09187 (17)0.37545 (16)0.0436 (4)0.50
H26A0.42300.15380.28940.052*0.50
O10.17377 (15)0.40333 (15)0.38534 (13)0.0541 (3)0.50
C25B0.43163 (19)0.04190 (18)0.58443 (17)0.0465 (4)0.50
H25B0.38590.06920.64370.056*0.50
C26B0.45348 (19)0.09187 (17)0.37545 (16)0.0436 (4)0.50
H26B0.42300.15380.28940.052*0.50
N40.38443 (16)0.13429 (15)0.45960 (14)0.0406 (3)0.50
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Mg0.0624 (5)0.0257 (4)0.0585 (5)−0.0250 (3)−0.0308 (4)0.0055 (3)
N10.0329 (6)0.0214 (5)0.0355 (6)−0.0107 (5)−0.0004 (5)−0.0098 (5)
N20.0306 (6)0.0205 (5)0.0339 (6)−0.0090 (4)0.0014 (5)−0.0103 (5)
C10.0312 (7)0.0237 (6)0.0315 (7)−0.0080 (5)0.0023 (5)−0.0125 (5)
C20.0379 (7)0.0262 (7)0.0306 (7)−0.0092 (6)−0.0013 (6)−0.0106 (6)
C30.0408 (8)0.0219 (6)0.0301 (7)−0.0105 (6)0.0026 (6)−0.0090 (5)
C40.0326 (7)0.0216 (6)0.0318 (7)−0.0093 (5)0.0063 (5)−0.0121 (5)
C50.0312 (7)0.0224 (6)0.0317 (7)−0.0103 (5)0.0074 (5)−0.0127 (5)
C60.0299 (7)0.0228 (6)0.0352 (7)−0.0112 (5)0.0076 (5)−0.0141 (6)
C70.0333 (7)0.0256 (7)0.0430 (8)−0.0143 (6)0.0042 (6)−0.0137 (6)
C80.0314 (7)0.0289 (7)0.0430 (8)−0.0134 (6)0.0013 (6)−0.0147 (6)
C90.0285 (7)0.0250 (6)0.0357 (7)−0.0094 (5)0.0038 (5)−0.0149 (6)
C100.0294 (7)0.0251 (6)0.0336 (7)−0.0084 (5)0.0027 (5)−0.0137 (6)
C110.0364 (7)0.0207 (6)0.0353 (7)−0.0104 (5)−0.0002 (6)−0.0111 (6)
C120.0351 (8)0.0512 (9)0.0553 (10)−0.0066 (7)0.0015 (7)−0.0325 (8)
C130.0335 (8)0.0517 (10)0.0795 (13)−0.0031 (7)−0.0095 (8)−0.0341 (10)
C140.0607 (11)0.0328 (8)0.0578 (11)−0.0146 (8)−0.0252 (9)−0.0103 (8)
C150.0873 (15)0.0642 (12)0.0346 (9)−0.0411 (11)−0.0020 (9)−0.0162 (8)
C160.0549 (10)0.0589 (10)0.0407 (9)−0.0323 (8)0.0104 (7)−0.0224 (8)
C170.0307 (7)0.0229 (6)0.0311 (7)−0.0108 (5)0.0024 (5)−0.0101 (5)
C180.0646 (11)0.0353 (8)0.0525 (10)−0.0237 (8)0.0282 (8)−0.0246 (8)
C190.0731 (12)0.0412 (9)0.0552 (10)−0.0326 (9)0.0328 (9)−0.0190 (8)
C200.0516 (9)0.0259 (7)0.0459 (9)−0.0199 (7)0.0004 (7)−0.0090 (6)
C210.0512 (9)0.0269 (7)0.0447 (8)−0.0114 (6)0.0011 (7)−0.0188 (7)
C220.0448 (8)0.0293 (7)0.0337 (7)−0.0133 (6)0.0081 (6)−0.0148 (6)
N30.0445 (7)0.0621 (9)0.0702 (9)−0.0178 (6)0.0123 (6)−0.0423 (8)
C230.0330 (14)0.0408 (16)0.0484 (17)−0.0179 (13)0.0103 (12)−0.0266 (14)
C240.0332 (7)0.0348 (7)0.0597 (9)−0.0124 (6)0.0090 (6)−0.0258 (7)
C25A0.0426 (9)0.0494 (9)0.0586 (10)−0.0149 (7)0.0168 (8)−0.0342 (9)
C26A0.0428 (9)0.0408 (8)0.0469 (9)−0.0141 (7)0.0085 (7)−0.0196 (7)
O10.0445 (7)0.0621 (9)0.0702 (9)−0.0178 (6)0.0123 (6)−0.0423 (8)
C25B0.0426 (9)0.0494 (9)0.0586 (10)−0.0149 (7)0.0168 (8)−0.0342 (9)
C26B0.0428 (9)0.0408 (8)0.0469 (9)−0.0141 (7)0.0085 (7)−0.0196 (7)
N40.0332 (7)0.0348 (7)0.0597 (9)−0.0124 (6)0.0090 (6)−0.0258 (7)
Geometric parameters (Å, º) top
Mg—N2i2.0552 (10)C12—C131.391 (2)
Mg—N22.0552 (10)C12—H120.9300
Mg—N1i2.0678 (11)C13—C141.366 (3)
Mg—N12.0678 (11)C13—H130.9300
Mg—N32.3798 (12)C14—C151.371 (3)
Mg—O1i2.3798 (12)C14—H140.9300
Mg—N3i2.3798 (12)C15—C161.386 (2)
N1—C11.3670 (17)C15—H150.9300
N1—C41.3720 (16)C16—H160.9300
N2—C91.3666 (17)C17—C181.380 (2)
N2—C61.3700 (16)C17—C221.3835 (18)
C1—C101.4121 (18)C18—C191.389 (2)
C1—C21.4421 (18)C18—H180.9300
C2—C31.3545 (19)C19—C201.377 (2)
C2—H20.9300C19—H190.9300
C3—C41.4371 (19)C20—C211.367 (2)
C3—H30.9300C20—H200.9300
C4—C51.4109 (18)C21—C221.3866 (19)
C5—C61.4068 (19)C21—H210.9300
C5—C171.5029 (17)C22—H220.9300
C6—C71.4425 (18)N3—C231.278 (3)
C7—C81.345 (2)C23—C241.429 (3)
C7—H70.9300C24—C26A1.355 (2)
C8—C91.4473 (18)C24—C25A1.357 (2)
C8—H80.9300C25A—C26Aii1.379 (2)
C9—C10i1.4079 (19)C25A—H25A0.9300
C10—C111.4962 (18)C26A—C25Aii1.379 (2)
C11—C121.379 (2)C26A—H26A0.9300
C11—C161.381 (2)
N2i—Mg—N2180.0N2—C9—C8109.27 (11)
N2i—Mg—N1i89.69 (4)C10i—C9—C8124.75 (12)
N2—Mg—N1i90.31 (4)C9i—C10—C1125.94 (12)
N2i—Mg—N190.31 (4)C9i—C10—C11116.57 (11)
N2—Mg—N189.69 (4)C1—C10—C11117.46 (12)
N1i—Mg—N1180.00 (6)C12—C11—C16118.37 (14)
N2i—Mg—N390.58 (4)C12—C11—C10121.54 (13)
N2—Mg—N389.42 (4)C16—C11—C10120.07 (13)
N1i—Mg—N392.22 (5)C11—C12—C13120.64 (16)
N1—Mg—N387.78 (5)C11—C12—H12119.7
N2i—Mg—O1i89.42 (4)C13—C12—H12119.7
N2—Mg—O1i90.58 (4)C14—C13—C12120.42 (17)
N1i—Mg—O1i87.78 (5)C14—C13—H13119.8
N1—Mg—O1i92.22 (5)C12—C13—H13119.8
N3—Mg—O1i180.0C13—C14—C15119.42 (15)
N2i—Mg—N3i89.42 (4)C13—C14—H14120.3
N2—Mg—N3i90.58 (4)C15—C14—H14120.3
N1i—Mg—N3i87.78 (5)C14—C15—C16120.40 (17)
N1—Mg—N3i92.22 (5)C14—C15—H15119.8
N3—Mg—N3i180.0C16—C15—H15119.8
O1i—Mg—N3i0.00 (5)C11—C16—C15120.74 (16)
C1—N1—C4106.86 (11)C11—C16—H16119.6
C1—N1—Mg126.20 (9)C15—C16—H16119.6
C4—N1—Mg126.85 (9)C18—C17—C22118.23 (12)
C9—N2—C6107.11 (10)C18—C17—C5121.67 (12)
C9—N2—Mg126.19 (9)C22—C17—C5120.06 (12)
C6—N2—Mg126.63 (9)C17—C18—C19120.57 (14)
N1—C1—C10125.41 (12)C17—C18—H18119.7
N1—C1—C2109.50 (11)C19—C18—H18119.7
C10—C1—C2125.07 (12)C20—C19—C18120.41 (15)
C3—C2—C1106.99 (12)C20—C19—H19119.8
C3—C2—H2126.5C18—C19—H19119.8
C1—C2—H2126.5C21—C20—C19119.51 (13)
C2—C3—C4107.15 (12)C21—C20—H20120.2
C2—C3—H3126.4C19—C20—H20120.2
C4—C3—H3126.4C20—C21—C22120.09 (13)
N1—C4—C5125.00 (12)C20—C21—H21120.0
N1—C4—C3109.50 (11)C22—C21—H21120.0
C5—C4—C3125.48 (12)C17—C22—C21121.14 (13)
C6—C5—C4125.88 (12)C17—C22—H22119.4
C6—C5—C17115.96 (11)C21—C22—H22119.4
C4—C5—C17118.15 (11)C23—N3—Mg129.10 (16)
N2—C6—C5125.82 (11)N3—C23—C24176.0 (3)
N2—C6—C7109.15 (11)C26A—C24—C25A118.27 (14)
C5—C6—C7125.04 (12)C26A—C24—C23123.09 (18)
C8—C7—C6107.45 (12)C25A—C24—C23118.58 (17)
C8—C7—H7126.3C24—C25A—C26Aii120.85 (15)
C6—C7—H7126.3C24—C25A—H25A119.6
C7—C8—C9107.02 (12)C26Aii—C25A—H25A119.6
C7—C8—H8126.5C24—C26A—C25Aii120.88 (15)
C9—C8—H8126.5C24—C26A—H26A119.6
N2—C9—C10i125.94 (12)C25Aii—C26A—H26A119.6
Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x+1, −y, −z+1.
Hydrogen-bond geometry (Å, º) top
Cg12 and Cg14 are the centroids of the N2/C6–C9 C17–C22 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C12—H12···Cg12iii0.932.973.8860 (19)168
C14—H14···Cg14iv0.932.703.584 (2)159
C21—H21···Cg12v0.932.853.6240 (18)141
Symmetry codes: (iii) x+1, y, z; (iv) −x+1, −y, −z+2; (v) −x, −y, −z+1.
Hydrogen-bond geometry (Å, º) top
Cg12 and Cg14 are the centroids of the N2/C6–C9 C17–C22 rings, respectively.
D—H···AD—HH···AD···AD—H···A
C12—H12···Cg12i0.932.973.8860 (19)168
C14—H14···Cg14ii0.932.703.584 (2)159
C21—H21···Cg12iii0.932.853.6240 (18)141
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y, −z+2; (iii) −x, −y, −z+1.
Acknowledgements top

We are grateful to the Fundacão para a Ciência e Tecnologia (FCT, Portugal) for support through projects SFRH/ BPD/24889/2005 and PTDC/BIA-PRO/103980/2008 and for funding the purchase of the single-crystal diffractometer. We thank Paula Branda from the Universidade de Aveiro for the crystal mounting and data collection.

references
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