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Acta Crystallogr Sect E Struct Rep Online. 2010 May 1; 66(Pt 5): o1160–o1161.
Published online 2010 April 24. doi:  10.1107/S1600536810014285
PMCID: PMC2979040

5,10,15,20-Tetra-2-furylporphyrin

Abstract

Mol­ecules of the title macrocycle, C36H22N4O4, are located on an inversion center. The porphyrin ring shows a wave-like conformation with adjacent pyrrole rings tilted above the porphyrin plane and the inter­porphyrin distance is 3.584 (3) Å. The dihedral angles between the meso-furyl groups and the porphyrin plane are 38.87 (7) and 48.29 (7)°; these are much smaller than those observed for meso-tetra­phenyl­porphyrin, indicating that the meso-furyl groups are more inclined towards the porphyrin plane. The decrease in the dihedral angle is due to the presence of intra­molecular hydro­den bonding between the meso-fury O atom and the β-pyrrole CH group. Intra­molecular N—H(...)N hydrogen bonds are also present.

Related literature

The electronic properties of porphyrin macrocycles can be altered by selectively introducing substituents at meso- or β-positions, see: Lindsey (2000 [triangle]). For the effect on the electronic properties of introducing five-membered heterocycles such as thio­phene and furan at the meso-position in place of six-membered aryl groups, see: Bhavana & Bhyrappa (2001 [triangle]); Purushothaman et al., (2001 [triangle]); Gupta & Ravikanth (2002 [triangle], 2003a [triangle],b [triangle], 2005 [triangle]). For the structure of 5,10,15,20-tetra­kis(phen­yl)porphyrin, see: Senge (2000 [triangle]).

An external file that holds a picture, illustration, etc.
Object name is e-66-o1160-scheme1.jpg

Experimental

Crystal data

  • C36H22N4O4
  • M r = 574.58
  • Monoclinic, An external file that holds a picture, illustration, etc.
Object name is e-66-o1160-efi1.jpg
  • a = 9.6068 (4) Å
  • b = 7.3956 (3) Å
  • c = 18.1770 (7) Å
  • β = 97.419 (4)°
  • V = 1280.63 (9) Å3
  • Z = 2
  • Mo Kα radiation
  • μ = 0.10 mm−1
  • T = 150 K
  • 0.28 × 0.23 × 0.17 mm

Data collection

  • Oxford Diffraction Xcalibur-S diffractometer
  • Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009 [triangle]) T min = 0.973, T max = 0.983
  • 14627 measured reflections
  • 4350 independent reflections
  • 2596 reflections with I > 2σ(I)
  • R int = 0.050

Refinement

  • R[F 2 > 2σ(F 2)] = 0.057
  • wR(F 2) = 0.140
  • S = 0.94
  • 4350 reflections
  • 203 parameters
  • H atoms treated by a mixture of independent and constrained refinement
  • Δρmax = 0.38 e Å−3
  • Δρmin = −0.30 e Å−3

Data collection: CrysAlis CCD (Oxford Diffraction, 2009 [triangle]); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2009 [triangle]); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 [triangle]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 [triangle]); molecular graphics: SHELXTL (Sheldrick, 2008 [triangle]); software used to prepare material for publication: SHELXTL.

Table 1
Hydrogen-bond geometry (Å, °)

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810014285/bt5220sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810014285/bt5220Isup2.hkl

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

Acknowledgments

Financial support from the DST and CSIR, Goverment of India, to MR is gratefully acknowledged.

supplementary crystallographic information

Comment

Porphyrin macrocycles are synthetically flexible and by selectively introducing substituents at meso- or β-positions, the electronic properties of the porphyrin ring can be altered at will for any application (Lindsey, 2000). Recently we, and others, have shown that introducing five membered heterocycles such as thiophene and furan at the meso-position in place of six membered aryl groups alter the electronic properties significantly (Bhavana & Bhyrappa, 2001; Purushothaman et al., 2001; Gupta & Ravikanth, 2002, 2003a, 2003b, and 2005). In the crystal structure of the Zn(II) derivative of 5,10,15,20-tetrathienylporphyrin, the structure was shown to correlate with the observed electronic properties (Purushothaman et al., 2001).

In the present paper, we report the crystal structure of 5,10,15,20-tetrakis(2-furyl)porphyrin (I) and compare it with the crystal structure of 5,10,15,20-tetrakis(phenyl)porphyrin (II) (Senge, 2000). The molecular structure of (I) is presented in Fig. 1. The porphyrin plane of (I) displays a wave like conformation with an interplanar porphyrin separation of 3.488 (Å). The aromatic nature of (I) is evident from the observation that the Cα-Cβ distance is greater than the Cβ-Cβ bond distance. The four inner pyrrole N atoms are almost in plane with four meso carbons. The bond distances and bond angles of (I) are altered relative to those of (II) revealing replacing phenyl groups with furyl groups at meso positions changes the porphyrin π-electron delocalization pathway. The dihedral angles of meso-furyl groups with respect to porphyrin plane in (I) are 38.87 (7)° and 48.29 (7)° and those of meso-phenyl groups in (II) are 61.0° and 61.3°. This significant decrease in the dihedral angle in case of (I) is due to presence of intramolecular hydroden bonding between meso-furyl "O" and β-pyrrole "CH". As is clear from Figure 1, the four meso-furyl"O" are involved in hydrogen bonding with two β-pyrrole "CH" which are opposite to each other. This bonding helps in the significant reduction of dihedral angle of meso-furyl groups with the plane of the porphyrin. As a result the meso-furyl groups are inclined more towards the porphyrin plane resulting in extension of π-delocalization of the porphyrin ring to the furyl groups. The observed spectroscopic properties of (I), such as large red shifts in absorption and emission maxima and significant downfield shifts of NH and \b-pyrrole protons in NMR as compared to (II) also in agreement with the enhanced π-delocalization in (I). Thus, the crystal structure presented here indicates that the porphyrin (I) adopts more planar structure as compared to porphyrin (II).

Experimental

In a 500 ml one necked round bottom flask fitted an with argon bubbler, furan-2-aldehyde (286 mg, 2.98 mmol) and pyrrole (210 ml, 2.98 mmol) in 300 ml of CH2Cl2 were condensed in the presence of BF3.OEt2 (120 ml of 2.5 M stock solution) under argon atmosphere for 1 h followed by oxidation with DDQ (674 mg, 2.98 mmol) in open air for additional 45 min. The solvent was removed under reduced pressure and the crude compound was purified by silica gel column chromatography using CH2Cl2 (62 mg, 12%). M. P. 300°C. Single crystals of (I) suitable for X-ray analysis were obtained by slow evaporation of a dichloromethane/n-hexane solution over a period of one week. Spectroscopic analysis, 1HNMR (300 MHz, CDCl3, δ in p.p.m.): -2.59 (s, 2H, NH), 7.04 (m, 4H, furyl), 7.32 (m, 4H, furyl), 8.14 (s, 4H, furyl), 9.16 (s, 8H, β-pyrrole); elemental analysis calculated for C36H22N4O4: C,75.25; H, 3.86; N, 9.75%; found: C,75.31; H, 3.92; N, 9.65%: 574.6; found: 574.7(M+).

Refinement

H atoms bonded to C were placed in geometrically idealized positions and constrained to ride on their parent atoms with a C—H distance of 0.95 Å [Uiso(H) = 1.2Ueq(C)]. The H attached to N was refined isotropically.

Figures

Fig. 1.
The molecular structure of C36H22N4O4 the showing the atom numbering scheme and 50% probability displacement ellipsoids. The weak C—H···O intramolecular interactions between C—H and O are shown by dashed lines.
Fig. 2.
The molecular packing for C36H22N4O4 viewed down the a axis. The weak C—H···O intramolecular interactions between C—H and O are shown by dashed lines.

Crystal data

C36H22N4O4F(000) = 596
Mr = 574.58Dx = 1.490 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybcCell parameters from 1578 reflections
a = 9.6068 (4) Åθ = 2.6–25.1°
b = 7.3956 (3) ŵ = 0.10 mm1
c = 18.1770 (7) ÅT = 150 K
β = 97.419 (4)°Block, black
V = 1280.63 (9) Å30.28 × 0.23 × 0.17 mm
Z = 2

Data collection

Oxford Diffraction Xcalibur-S diffractometer2596 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.050
graphiteθmax = 32.7°, θmin = 3.3°
ω scansh = −11→14
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009)k = −11→10
Tmin = 0.973, Tmax = 0.983l = −27→27
14627 measured reflections2 standard reflections every 50 reflections
4350 independent reflections intensity decay: <2%

Refinement

Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.057Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.140H atoms treated by a mixture of independent and constrained refinement
S = 0.94w = 1/[σ2(Fo2) + (0.0704P)2] where P = (Fo2 + 2Fc2)/3
4350 reflections(Δ/σ)max < 0.001
203 parametersΔρmax = 0.38 e Å3
0 restraintsΔρmin = −0.30 e Å3

Special details

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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)

xyzUiso*/Ueq
O10.12370 (14)0.14955 (18)0.78524 (7)0.0328 (3)
O20.28868 (13)1.19097 (16)0.53303 (7)0.0277 (3)
N10.14624 (14)0.57702 (18)0.58457 (7)0.0182 (3)
N20.04097 (14)0.74030 (19)0.44418 (8)0.0181 (3)
H2N0.018 (2)0.644 (3)0.4727 (11)0.033 (6)*
C10.17490 (17)0.4903 (2)0.65124 (9)0.0190 (3)
C20.25816 (18)0.6045 (2)0.70508 (9)0.0228 (4)
H2A0.28960.57540.75540.027*
C30.28217 (18)0.7587 (2)0.67017 (9)0.0223 (4)
H3A0.33280.86080.69100.027*
C40.21545 (17)0.7390 (2)0.59420 (9)0.0182 (3)
C50.12791 (17)0.3159 (2)0.66826 (9)0.0183 (3)
C60.19861 (19)0.2322 (2)0.73637 (9)0.0211 (3)
C70.33718 (18)0.2124 (2)0.75868 (9)0.0232 (4)
H7A0.41160.25660.73400.028*
C80.3506 (2)0.1135 (3)0.82580 (11)0.0320 (4)
H8A0.43580.08000.85510.038*
C90.2214 (2)0.0765 (3)0.84007 (11)0.0334 (5)
H9A0.19920.00980.88170.040*
C100.22148 (16)0.8718 (2)0.53867 (9)0.0184 (3)
C110.32446 (18)1.0178 (2)0.55473 (9)0.0199 (3)
C120.45911 (18)1.0137 (2)0.58713 (9)0.0227 (4)
H12A0.50960.91030.60680.027*
C130.51107 (19)1.1943 (3)0.58618 (10)0.0287 (4)
H13A0.60251.23470.60530.034*
C140.4052 (2)1.2961 (2)0.55300 (10)0.0284 (4)
H14A0.41031.42260.54460.034*
C150.13864 (16)0.8702 (2)0.46911 (9)0.0185 (3)
C160.13469 (18)1.0021 (2)0.41186 (9)0.0231 (4)
H16A0.19321.10580.41250.028*
C170.03278 (18)0.9546 (2)0.35596 (10)0.0226 (4)
H17A0.00571.02140.31180.027*
C18−0.02633 (17)0.7862 (2)0.37546 (9)0.0183 (3)

Atomic displacement parameters (Å2)

U11U22U33U12U13U23
O10.0354 (8)0.0311 (7)0.0315 (7)−0.0065 (6)0.0025 (6)0.0025 (6)
O20.0274 (7)0.0201 (6)0.0345 (7)−0.0029 (5)0.0002 (5)−0.0029 (5)
N10.0185 (7)0.0161 (6)0.0193 (7)−0.0016 (5)−0.0006 (5)−0.0015 (5)
N20.0181 (7)0.0163 (7)0.0193 (7)−0.0023 (6)0.0005 (5)−0.0004 (5)
C10.0193 (8)0.0179 (8)0.0195 (8)−0.0011 (7)0.0010 (6)−0.0024 (6)
C20.0244 (9)0.0252 (9)0.0178 (8)−0.0035 (7)−0.0015 (6)−0.0026 (7)
C30.0222 (9)0.0231 (8)0.0204 (8)−0.0048 (7)−0.0015 (6)−0.0040 (7)
C40.0158 (8)0.0181 (8)0.0204 (8)0.0007 (6)0.0010 (6)−0.0024 (6)
C50.0171 (8)0.0191 (8)0.0183 (8)0.0003 (6)0.0011 (6)−0.0013 (6)
C60.0269 (9)0.0165 (8)0.0194 (8)−0.0013 (7)0.0013 (6)−0.0023 (6)
C70.0192 (8)0.0235 (9)0.0264 (9)0.0014 (7)0.0008 (7)0.0066 (7)
C80.0348 (11)0.0229 (9)0.0337 (10)−0.0003 (8)−0.0126 (8)0.0036 (8)
C90.0527 (14)0.0231 (9)0.0229 (9)−0.0074 (9)−0.0005 (9)0.0051 (8)
C100.0163 (8)0.0162 (7)0.0226 (8)0.0003 (6)0.0024 (6)−0.0024 (6)
C110.0230 (9)0.0166 (8)0.0205 (8)−0.0017 (7)0.0041 (6)−0.0019 (6)
C120.0200 (9)0.0233 (8)0.0243 (8)0.0014 (7)0.0010 (7)0.0008 (7)
C130.0206 (9)0.0346 (10)0.0311 (10)−0.0094 (8)0.0041 (7)−0.0100 (8)
C140.0331 (11)0.0193 (9)0.0340 (10)−0.0099 (8)0.0087 (8)−0.0073 (8)
C150.0143 (8)0.0178 (8)0.0234 (8)−0.0011 (6)0.0024 (6)−0.0013 (6)
C160.0230 (9)0.0198 (8)0.0258 (9)−0.0051 (7)0.0002 (7)0.0022 (7)
C170.0243 (9)0.0202 (8)0.0228 (8)−0.0021 (7)0.0010 (7)0.0040 (7)
C180.0186 (8)0.0178 (8)0.0181 (8)0.0005 (6)0.0008 (6)−0.0001 (6)

Geometric parameters (Å, °)

O1—C61.359 (2)C7—C81.414 (2)
O1—C91.387 (2)C7—H7A0.9500
O2—C111.371 (2)C8—C91.329 (3)
O2—C141.373 (2)C8—H8A0.9500
N1—C11.367 (2)C9—H9A0.9500
N1—C41.371 (2)C10—C151.404 (2)
N2—C181.373 (2)C10—C111.468 (2)
N2—C151.378 (2)C11—C121.351 (2)
N2—H2N0.92 (2)C12—C131.427 (3)
C1—C51.414 (2)C12—H12A0.9500
C1—C21.452 (2)C13—C141.344 (3)
C2—C31.340 (2)C13—H13A0.9500
C2—H2A0.9500C14—H14A0.9500
C3—C41.453 (2)C15—C161.423 (2)
C3—H3A0.9500C16—C171.363 (2)
C4—C101.415 (2)C16—H16A0.9500
C5—C18i1.398 (2)C17—C181.432 (2)
C5—C61.470 (2)C17—H17A0.9500
C6—C71.349 (2)C18—C5i1.398 (2)
C6—O1—C9106.18 (15)C8—C9—O1109.99 (17)
C11—O2—C14106.71 (14)C8—C9—H9A125.0
C1—N1—C4104.95 (13)O1—C9—H9A125.0
C18—N2—C15110.34 (14)C15—C10—C4124.46 (15)
C18—N2—H2N125.5 (13)C15—C10—C11118.31 (15)
C15—N2—H2N123.7 (13)C4—C10—C11117.21 (14)
N1—C1—C5126.03 (15)C12—C11—O2109.69 (15)
N1—C1—C2110.81 (14)C12—C11—C10130.76 (16)
C5—C1—C2123.13 (15)O2—C11—C10119.51 (14)
C3—C2—C1106.82 (15)C11—C12—C13106.88 (16)
C3—C2—H2A126.6C11—C12—H12A126.6
C1—C2—H2A126.6C13—C12—H12A126.6
C2—C3—C4106.44 (15)C14—C13—C12106.52 (16)
C2—C3—H3A126.8C14—C13—H13A126.7
C4—C3—H3A126.8C12—C13—H13A126.7
N1—C4—C10125.42 (14)C13—C14—O2110.19 (16)
N1—C4—C3110.87 (14)C13—C14—H14A124.9
C10—C4—C3123.71 (15)O2—C14—H14A124.9
C18i—C5—C1125.99 (15)N2—C15—C10125.79 (15)
C18i—C5—C6117.66 (14)N2—C15—C16106.53 (14)
C1—C5—C6116.27 (14)C10—C15—C16127.66 (15)
C7—C6—O1109.88 (15)C17—C16—C15108.49 (15)
C7—C6—C5129.05 (16)C17—C16—H16A125.8
O1—C6—C5120.94 (15)C15—C16—H16A125.8
C6—C7—C8107.00 (16)C16—C17—C18108.02 (15)
C6—C7—H7A126.5C16—C17—H17A126.0
C8—C7—H7A126.5C18—C17—H17A126.0
C9—C8—C7106.94 (16)N2—C18—C5i126.57 (15)
C9—C8—H8A126.5N2—C18—C17106.56 (14)
C7—C8—H8A126.5C5i—C18—C17126.81 (15)
C4—N1—C1—C5−178.98 (16)N1—C4—C10—C11−167.21 (15)
C4—N1—C1—C22.96 (18)C3—C4—C10—C1113.4 (2)
N1—C1—C2—C3−1.3 (2)C14—O2—C11—C12−0.13 (18)
C5—C1—C2—C3−179.43 (16)C14—O2—C11—C10−178.14 (14)
C1—C2—C3—C4−0.86 (19)C15—C10—C11—C12−136.32 (19)
C1—N1—C4—C10177.00 (15)C4—C10—C11—C1242.0 (2)
C1—N1—C4—C3−3.52 (18)C15—C10—C11—O241.2 (2)
C2—C3—C4—N12.8 (2)C4—C10—C11—O2−140.43 (15)
C2—C3—C4—C10−177.70 (15)O2—C11—C12—C130.29 (19)
N1—C1—C5—C18i−11.1 (3)C10—C11—C12—C13177.99 (16)
C2—C1—C5—C18i166.76 (16)C11—C12—C13—C14−0.3 (2)
N1—C1—C5—C6165.50 (15)C12—C13—C14—O20.3 (2)
C2—C1—C5—C6−16.7 (2)C11—O2—C14—C13−0.09 (19)
C9—O1—C6—C70.23 (19)C18—N2—C15—C10176.59 (15)
C9—O1—C6—C5176.41 (15)C18—N2—C15—C16−1.62 (18)
C18i—C5—C6—C7126.53 (19)C4—C10—C15—N2−0.6 (3)
C1—C5—C6—C7−50.3 (2)C11—C10—C15—N2177.63 (15)
C18i—C5—C6—O1−48.8 (2)C4—C10—C15—C16177.22 (16)
C1—C5—C6—O1134.29 (16)C11—C10—C15—C16−4.5 (3)
O1—C6—C7—C8−0.7 (2)N2—C15—C16—C172.51 (19)
C5—C6—C7—C8−176.46 (17)C10—C15—C16—C17−175.66 (17)
C6—C7—C8—C90.9 (2)C15—C16—C17—C18−2.4 (2)
C7—C8—C9—O1−0.8 (2)C15—N2—C18—C5i177.44 (16)
C6—O1—C9—C80.4 (2)C15—N2—C18—C170.17 (18)
N1—C4—C10—C1511.0 (3)C16—C17—C18—N21.42 (19)
C3—C4—C10—C15−168.37 (16)C16—C17—C18—C5i−175.84 (16)

Symmetry codes: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, °)

D—H···AD—HH···AD···AD—H···A
N2—H2N···N10.92 (2)2.29 (2)2.886 (2)121.5 (16)
N2—H2N···N1i0.92 (2)2.41 (2)2.9618 (19)118.1 (15)
C16—H16A···O20.952.352.855 (2)113
C17—H17A···O1i0.952.392.906 (2)114

Symmetry codes: (i) −x, −y+1, −z+1.

Footnotes

Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: BT5220).

References

  • Bhavana, P. & Bhyrappa, P. (2001). Chem. Phys. Lett.349, 399–404.
  • Gupta, I. & Ravikanth, M. (2002). Tetrahedron Lett.43, 9453–9455.
  • Gupta, I. & Ravikanth, M. (2003a). Eur. J. Org. Chem. pp. 4392–4400.
  • Gupta, I. & Ravikanth, M. (2003b). Tetrahedron, 43, 6131–6139.
  • Gupta, I. & Ravikanth, M. (2005). J. Chem. Sci.117, 161–166.
  • Lindsey, J. S. (2000). The Porphyrin Handbook, Vol. 1, edited by K. M. Kadish, K. M. Smith & R. Guilard, pp. 45–118. San Diego: Academic Press.
  • Oxford Diffraction (2009). CrysAlis CCD and CrysAlis RED Oxford Diffraction Ltd, Yarnton, England.
  • Purushothaman, B., Varghese, B. & Bhyrappa, P. (2001). Acta Cryst. C57, 252–253. [PubMed]
  • Senge, M. O. (2000). The Porphyrin Handbook, Vol. 1, edited by K. M. Kadish, K. M. Smith & R. Guilard, pp. 239–347. New York: Academic Press.
  • Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. [PubMed]

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