Molecules of the title compound, porphyrin-54,104,154,204-tetrabenzoic acid, C48H30N4O8, lie on sites of 2/m symmetry in the space group Cmca. The crystals consist of doubly interwoven two-dimensional supramolecular arrays sustained by multiple (COOH)2 cyclic dimeric hydrogen bonds, each molecule of the porphyrintetrabenzoic acid coordinating to four neighbouring species. This structure, which encloses substantial spaces occupied by disordered dimethylformamide solvent molecules, represents yet another supramolecular isomer of this porphyrin.
Supporting information
CCDC reference: 655498
Crystals of (I) were obtained accidentally, while trying to react the free base
tetra-acid porphyrin with Gd3+ ions in the presence of dimethylformamide, in
an effort to prepare the corresponding metal–organic framework material (all
reactants are commercially available). Single crystals were obtained by
recrystallization from dimethylformamide. [Please check added text]
H atoms bound to C and N were located in calculated positions and were
constrained to ride on their parent atoms, with N—H = 0.88 and C—H = 0.95 Å, and with Uiso(H) = 1.2Ueq(C,N). The inner
pyrrole H atoms are disordered between the four N sites. H atoms attached to O
atoms were located in a difference Fourier map and their atomic parameters
were allowed to refine freely; O—H = 0.94 (3) Å. The porphyrin molecules
reside on special positions of 2/m symmetry at (0, 0, 1/2). The solvent
moiety is disordered about a similar site at (0, 1/2, 1/2), but it could not
be reliably modelled as discrete atoms. Correspondingly, the contribution of
the solvent was subtracted from the diffraction data using the SQUEEZE
procedure in PLATON (Spek, 2003). The solvent-accessible voids were
estimated to be 487 Å3, 12% of the unit-cell volume. The residual
electron-density count was assessed as 132 electrons per unit cell, which is
consistent with nearly four molecules of the dimethylformamide solvent. The
maximum residual electron density, 0.61 e Å-3, is located at the inversion
centre in the porphyrin unit, 1.16 Å from atom H6 and 1.23 Å from atom H7.
Data collection: COLLECT (Nonius, 1999); cell refinement: DENZO (Otwinowski & Minor, 1997); data reduction: DENZO; program(s) used to solve structure: SIR97 (Altomare et al., 1994); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEPIII (Burnett & Johnson, 1996) and Mercury (Macrae et al.,
2006); software used to prepare material for publication: SHELXL97.
meso-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin
top
Crystal data top
C48H30N4O8 | F(000) = 1640 |
Mr = 790.76 | Dx = 1.297 Mg m−3 |
Orthorhombic, Cmca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2bc 2 | Cell parameters from 2650 reflections |
a = 31.0164 (3) Å | θ = 1.4–27.9° |
b = 8.5897 (11) Å | µ = 0.09 mm−1 |
c = 15.1952 (6) Å | T = 110 K |
V = 4048.3 (5) Å3 | Plate, red |
Z = 4 | 0.50 × 0.25 × 0.02 mm |
Data collection top
Nonius KappaCCD area-detector diffractometer | 1653 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.072 |
Graphite monochromator | θmax = 26.0°, θmin = 2.6° |
Detector resolution: 12.8 pixels mm-1 | h = 0→38 |
1 ° ω scans | k = 0→10 |
15184 measured reflections | l = −18→0 |
2033 independent reflections | |
Refinement top
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.059 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.138 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.13 | w = 1/[σ2(Fo2) + (0.0482P)2 + 8.4601P] where P = (Fo2 + 2Fc2)/3 |
2033 reflections | (Δ/σ)max < 0.001 |
141 parameters | Δρmax = 0.61 e Å−3 |
0 restraints | Δρmin = −0.23 e Å−3 |
Crystal data top
C48H30N4O8 | V = 4048.3 (5) Å3 |
Mr = 790.76 | Z = 4 |
Orthorhombic, Cmca | Mo Kα radiation |
a = 31.0164 (3) Å | µ = 0.09 mm−1 |
b = 8.5897 (11) Å | T = 110 K |
c = 15.1952 (6) Å | 0.50 × 0.25 × 0.02 mm |
Data collection top
Nonius KappaCCD area-detector diffractometer | 1653 reflections with I > 2σ(I) |
15184 measured reflections | Rint = 0.072 |
2033 independent reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.059 | 0 restraints |
wR(F2) = 0.138 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.13 | Δρmax = 0.61 e Å−3 |
2033 reflections | Δρmin = −0.23 e Å−3 |
141 parameters | |
Special details top
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. Disordered molecules of DMF solvent are included in the interporphyrin voids,
which could not be modeled by discrete atoms. Correspondingly, their
contribution to the diffraction pattern was subtracted by the Squeeze
procedure (Spek, 2003). |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | Occ. (<1) |
C1 | 0.02163 (7) | 0.2697 (3) | 0.26741 (14) | 0.0225 (5) | |
H1 | 0.0399 | 0.3255 | 0.2284 | 0.027* | |
C2 | 0.03508 (7) | 0.1680 (3) | 0.33848 (14) | 0.0206 (5) | |
C3 | 0.07880 (7) | 0.1349 (3) | 0.35778 (14) | 0.0199 (5) | |
C4 | 0.09344 (7) | 0.0586 (3) | 0.43355 (14) | 0.0197 (5) | |
C5 | 0.13718 (7) | 0.0334 (3) | 0.45934 (15) | 0.0205 (5) | |
H5 | 0.1620 | 0.0588 | 0.4256 | 0.025* | |
N6 | 0.0000 | 0.1109 (3) | 0.38255 (16) | 0.0200 (6) | |
H6 | 0.0000 | 0.0504 | 0.4293 | 0.024* | 0.50 |
N7 | 0.06792 (8) | 0.0000 | 0.5000 | 0.0202 (6) | |
H7 | 0.0395 | 0.0000 | 0.5000 | 0.024* | 0.50 |
C8 | 0.11154 (7) | 0.1762 (3) | 0.28923 (14) | 0.0201 (5) | |
C9 | 0.14847 (7) | 0.2645 (3) | 0.30741 (15) | 0.0224 (5) | |
H9 | 0.1526 | 0.3065 | 0.3646 | 0.027* | |
C10 | 0.17897 (7) | 0.2910 (3) | 0.24290 (15) | 0.0235 (5) | |
H10 | 0.2038 | 0.3513 | 0.2561 | 0.028* | |
C11 | 0.17356 (7) | 0.2299 (3) | 0.15842 (15) | 0.0230 (5) | |
C12 | 0.13630 (7) | 0.1451 (3) | 0.13907 (15) | 0.0246 (5) | |
H12 | 0.1320 | 0.1051 | 0.0815 | 0.029* | |
C13 | 0.10583 (7) | 0.1195 (3) | 0.20345 (15) | 0.0236 (5) | |
H13 | 0.0805 | 0.0624 | 0.1895 | 0.028* | |
C14 | 0.20637 (7) | 0.2467 (3) | 0.08862 (16) | 0.0245 (5) | |
O15 | 0.23890 (5) | 0.3403 (2) | 0.10779 (11) | 0.0329 (5) | |
H15 | 0.2592 (10) | 0.329 (4) | 0.062 (2) | 0.049* | |
O16 | 0.20328 (5) | 0.1781 (2) | 0.01805 (11) | 0.0310 (4) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
C1 | 0.0201 (10) | 0.0306 (12) | 0.0168 (11) | −0.0005 (10) | 0.0001 (9) | 0.0061 (10) |
C2 | 0.0191 (11) | 0.0258 (12) | 0.0169 (10) | −0.0013 (9) | −0.0011 (9) | 0.0026 (10) |
C3 | 0.0178 (11) | 0.0251 (12) | 0.0168 (10) | −0.0007 (9) | 0.0013 (9) | −0.0004 (9) |
C4 | 0.0169 (11) | 0.0243 (12) | 0.0178 (11) | 0.0010 (9) | 0.0029 (9) | −0.0007 (9) |
C5 | 0.0173 (11) | 0.0253 (12) | 0.0189 (11) | 0.0001 (9) | 0.0023 (9) | 0.0004 (9) |
N6 | 0.0163 (13) | 0.0300 (15) | 0.0138 (13) | 0.000 | 0.000 | 0.0032 (11) |
N7 | 0.0179 (13) | 0.0280 (15) | 0.0147 (13) | 0.000 | 0.000 | 0.0023 (11) |
C8 | 0.0181 (11) | 0.0261 (12) | 0.0161 (11) | 0.0031 (9) | 0.0025 (9) | 0.0038 (9) |
C9 | 0.0178 (11) | 0.0309 (13) | 0.0185 (11) | 0.0021 (9) | −0.0008 (9) | 0.0028 (10) |
C10 | 0.0201 (11) | 0.0297 (13) | 0.0207 (11) | −0.0012 (9) | 0.0017 (9) | 0.0033 (10) |
C11 | 0.0218 (12) | 0.0264 (12) | 0.0207 (12) | 0.0030 (9) | 0.0034 (9) | 0.0063 (10) |
C12 | 0.0239 (12) | 0.0317 (13) | 0.0181 (11) | 0.0003 (10) | 0.0031 (9) | 0.0022 (10) |
C13 | 0.0193 (11) | 0.0321 (13) | 0.0193 (12) | −0.0026 (9) | 0.0001 (9) | 0.0021 (10) |
C14 | 0.0200 (11) | 0.0294 (12) | 0.0239 (12) | 0.0039 (10) | 0.0033 (10) | 0.0052 (10) |
O15 | 0.0255 (10) | 0.0491 (11) | 0.0241 (9) | −0.0062 (8) | 0.0090 (7) | −0.0017 (8) |
O16 | 0.0279 (9) | 0.0415 (10) | 0.0236 (9) | −0.0026 (8) | 0.0103 (7) | −0.0031 (8) |
Geometric parameters (Å, º) top
C1—C1i | 1.342 (4) | C8—C9 | 1.401 (3) |
C1—C2 | 1.450 (3) | C8—C13 | 1.403 (3) |
C1—H1 | 0.9500 | C9—C10 | 1.381 (3) |
C2—N6 | 1.369 (3) | C9—H9 | 0.9500 |
C2—C3 | 1.416 (3) | C10—C11 | 1.397 (3) |
C3—C4 | 1.400 (3) | C10—H10 | 0.9500 |
C3—C8 | 1.497 (3) | C11—C12 | 1.397 (3) |
C4—N7 | 1.378 (3) | C11—C14 | 1.477 (3) |
C4—C5 | 1.429 (3) | C12—C13 | 1.378 (3) |
C5—C5ii | 1.362 (4) | C12—H12 | 0.9500 |
C5—H5 | 0.9500 | C13—H13 | 0.9500 |
N6—C2i | 1.369 (3) | C14—O16 | 1.228 (3) |
N6—H6 | 0.8800 | C14—O15 | 1.323 (3) |
N7—C4ii | 1.378 (3) | O15—H15 | 0.94 (3) |
N7—H7 | 0.8800 | | |
| | | |
C1i—C1—C2 | 106.72 (12) | C9—C8—C3 | 123.1 (2) |
C1i—C1—H1 | 126.6 | C13—C8—C3 | 118.6 (2) |
C2—C1—H1 | 126.6 | C10—C9—C8 | 120.6 (2) |
N6—C2—C3 | 126.0 (2) | C10—C9—H9 | 119.7 |
N6—C2—C1 | 110.58 (19) | C8—C9—H9 | 119.7 |
C3—C2—C1 | 123.4 (2) | C9—C10—C11 | 120.5 (2) |
C4—C3—C2 | 125.1 (2) | C9—C10—H10 | 119.7 |
C4—C3—C8 | 117.58 (19) | C11—C10—H10 | 119.7 |
C2—C3—C8 | 117.23 (19) | C10—C11—C12 | 119.3 (2) |
N7—C4—C3 | 125.9 (2) | C10—C11—C14 | 122.7 (2) |
N7—C4—C5 | 106.79 (19) | C12—C11—C14 | 118.0 (2) |
C3—C4—C5 | 127.2 (2) | C13—C12—C11 | 120.1 (2) |
C5ii—C5—C4 | 108.23 (12) | C13—C12—H12 | 120.0 |
C5ii—C5—H5 | 125.9 | C11—C12—H12 | 120.0 |
C4—C5—H5 | 125.9 | C12—C13—C8 | 121.2 (2) |
C2i—N6—C2 | 105.3 (3) | C12—C13—H13 | 119.4 |
C2i—N6—H6 | 127.3 | C8—C13—H13 | 119.4 |
C2—N6—H6 | 127.3 | O16—C14—O15 | 122.9 (2) |
C4ii—N7—C4 | 109.9 (3) | O16—C14—C11 | 121.8 (2) |
C4ii—N7—H7 | 125.0 | O15—C14—C11 | 115.3 (2) |
C4—N7—H7 | 125.0 | C14—O15—H15 | 106.6 (19) |
C9—C8—C13 | 118.3 (2) | | |
Symmetry codes: (i) −x, y, z; (ii) x, −y, −z+1. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O15—H15···O16iii | 0.94 (3) | 1.69 (3) | 2.626 (2) | 176 (3) |
Symmetry code: (iii) −x+1/2, −y+1/2, −z. |
Experimental details
Crystal data |
Chemical formula | C48H30N4O8 |
Mr | 790.76 |
Crystal system, space group | Orthorhombic, Cmca |
Temperature (K) | 110 |
a, b, c (Å) | 31.0164 (3), 8.5897 (11), 15.1952 (6) |
V (Å3) | 4048.3 (5) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.50 × 0.25 × 0.02 |
|
Data collection |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15184, 2033, 1653 |
Rint | 0.072 |
(sin θ/λ)max (Å−1) | 0.617 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.059, 0.138, 1.13 |
No. of reflections | 2033 |
No. of parameters | 141 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.61, −0.23 |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O15—H15···O16i | 0.94 (3) | 1.69 (3) | 2.626 (2) | 176 (3) |
Symmetry code: (i) −x+1/2, −y+1/2, −z. |
The supramolecular chemistry of the title compound, (I), has been widely studied in recent years in an effort to formulate network and framework solids (George & Goldberg, 2006; George et al., 2006; Goldberg, 2005 and references therein; Diskin-Posner & Goldberg, 1999; Dastidar et al., 1996). Compound (I) provides a classic example of an organic moiety with multiple complementary terminal functional groups directed in four diverging directions of the equatorial molecular plane that exhibit a high propensity for self-assembling into hydrogen-bonded two-dimensional nets. One of the possible interaction modes involves association of every porphyrin unit to four different neighbouring species via four head-to-head (COOH)2 cyclic dimeric associations. This leads to the formation of quadrangular grid arrays with large pores and varying shapes, to be filled during the crystallization process either by occlusion of another guest/solvent component to avoid interweaving and allow a stacked organization of these arrays, or by their self-interpenetration.
The different modes of the self-assembly of (I) (George & Goldberg, 2006; George et al., 2006; Diskin-Posner & Goldberg, 1999) represent a phenomenon known as supramolecular isomerism of the conformation and catenane types (Moulton & Zaworotko, 2001). Fig. 1 shows the molecular structure of (I) (as observed in this study), which resides on a special position of site symmetry 2/m. The supramolecular assembly of (I) into flat grid arrays sustained by cooperative (COOH)2-type four-point hydrogen bonding is illustrated in Fig. 2. Every molecule of the tetra-acid effectively connects to four neighbouring species, being involved in eight nearly linear O—H···O interactions at O···O = 2.626 (2) Å.
Within the two-dimensional supramolecular assembly, there are nearly square spaces with dimensions ca 18 × 18 Å2 between the van der Waals surfaces. The crystalline architecture involves double interpenetration of these networks partly to fill the empty space (Fig. 3). The remaining voids between these hydrogen-bonded networks are occupied by molecules of the dimethylformamide solvent, which could not, however, be modelled as discrete atoms.
This structure represents a catenane-type supramolecular isomer of other architectures of (I) observed earlier (George & Goldberg, 2006; Diskin-Posner & Goldberg, 1999). In the latter, the supramolecular networking of (I) exhibits the same interporphyrin connectivity via cyclic dimeric hydrogen-bond synthons, but the open networks form offset stacks one on top of the other. It also represents a conformation-type supramolecular isomer, with differently shaped grids within the individual layers. Thus, the networks in this study represent a regular nearly square grid with van der Waals width of about 18 Å. In another structure with similarly doubly interpenetrating networks of (I), a rhomboid grid with van der Waals width of about only 16 Å was observed (George et al., 2006). On the other hand, in yet another non-interpenetrating structure of network arrays of the porphyrin tetra-acid, the supramolecular networks were found to be characterized by a distorted grid with alternating spacing of about 15 and 20 Å (George & Goldberg, 2006). The previously observed conformational isomers of the grid networks are shown in Fig. 4.
The various distortions could be associated with the tendency to minimize the interporphyrin void space in such hydrogen-bonded networks. The supramolecular isomerism discussed above resembles to some extent the appearance of isomeric interwoven and non-interwoven supramolecular hexagonal networks in solids of 1,3,5-benzenetricarboxylic acid (Moulton & Zaworotko, 2001; Herbstein, 1987).