organic compounds
E)-[1,4-phenylenebis(azan-1-yl-1-ylidene)]bis(methan-1-yl-1-ylidene)bis(1H-pyrrole-2,1-diyl)}dipropanoate
of diethyl 3,3′-{2,2′-(1aDepartment of Chemistry, College of Education for Pure Science, University of Basrah, Iraq, bSchool of chemistry, University of Manchester, Oxford Road, Manchester, M13 9PL, UK, and cDepartment of Chemistry, College of Education (Ibn Al-Haitham) for Pure Science, University of Baghdad, Iraq
*Correspondence e-mail: mohamadaljeboori@yahoo.com
The complete molecule of the title compound, C26H30N4O4, is generated by crystallographic inversion symmetry. The dihedral angle between the planes of the benzene and pyrrole rings is 45.20 (11)°; the N atom bonded to the the benzene ring and the pyrrole N atom are in a syn conformation. The side chain adopts an extended conformation [N—C—C—C = 169.07 (17)° and C—O—C—C = −176.54 (17)°]. No directional interactions could be identified in the crystal packing.
Keywords: crystal structure; Schiff base; bis(pyrrole ester).
CCDC reference: 1053761
1. Related literature
For the synthesis of dipyrrole Schiff base ligands, see: Meghdadi et al.(2010); Munro et al. (2004). For the synthesis of pyrrole ester precursors, see: Koriatopoulou et al. (2008); Singh & Pal (2010). For the preparation of the title compound, see: Yang et al. (2004); Ourari et al. (2013).
2. Experimental
2.1. Crystal data
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2.3. Refinement
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Data collection: CrysAlis PRO (Agilent, 2013); cell CrysAlis PRO; data reduction: CrysAlis PRO; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2.
Supporting information
CCDC reference: 1053761
10.1107/S2056989015005113/hb7371sup1.cif
contains datablock I. DOI:Structure factors: contains datablock I. DOI: 10.1107/S2056989015005113/hb7371Isup2.hkl
FT-IR data were recorded on Agilent 8400s FT-IR while NMR data were collected on Bruker 500 MHz spectrometer in CDCl3 solutions. The assignment of the chemical shifts for the NMR data were made following numbering shown in structure. The title compound was prepared in two steps and as follows: Preparation of ethyl(2-formyl-1H-pyrrole-1-yl)-propanoate(L): It was prepared by literature procedures (Koriatopoulou et al., (2008); Singh & Pal (2010), as follows: To a mixture of 1H-pyrrole-2-carbaldehyde(1.00g,10.51mmol), K2CO3 (2.90g, 21.02mmol) and (2.64g, 10.51mmol) of 18-crown-6 in dry 1,4-dioxane (20ml), was added a solution of ethyl bromopropanoate (2.17g, 12mmol) in dry 1,4-dioxane (20ml)dropwise over a period of 30 min.The reaction mixture was allowed to reflux under nitrogen atmosphere for 6h, and then the solvent was removed under reduced pressure. Water (50ml) was added to the residue, and the mixture was extracted with ethyl acetate (3 × 15ml). The combined organic layers were washed with brine (15ml), and then dried over Na2SO4.The solvent was removed under reduced pressure, and the oily residue was purified by flash ν(C=O) aldehyde moiety. 172 0 ν (C=O) ester group. NMR data (p.p.m),δH (500 MHz, CDCl3): 1.10 (3H, t, C13-H), 2.70 (2H, t, C9-H), 4.01 (2H, Q, C12-H), 4.47 (2H, t, C8-H), 6.09 (1H, t, C3-H),6.83 (1H, d, C4-H), 6.94 (1H, d, C2-H) and 9.43 (1H, s, C6-H); δC (125.75 MHz, CDCl3):14.06 C13, 35.68 C9, 44.71 C8, 60.62 C12,109.53 C3, 125.17 C 4, 131.02 C5 and 132.23 C2, and C=O of the carboxylate moiety at 171.17 (C10) and 179.15 for C6. The positive ES at m/z =196.4 (M+H)+ (80 %) for C10H13NO3, requires =195.1. The other peaks which detected at m/z =167.4 (100 %), 123.3 (50 %), 95.2 (5 %) and 67 (6 %) correspond to [M-CH2CH3]+, [M-(CH2CH3+CO2)]+, [M-(CH2CH3+CO2+CH2+CH2)]+ and [M-(CH2CH3+CO2+CH2CH2+CO)]+, respectively.Synthesis of the title Schiff-base:achieved using standard method as follows: To a mixture of L (1.95g, 10mmol) in ethanol (20ml)with 3 drops of glacial acetic acid, a solution of p-phenylendiamine (0.5g, 5mmol) in ethanol (20ml) was added dropwise over a period of 20 min. The reaction mixture was allowed to reflux for 3h, and then cooled to room temperature. A white precipitate was collected by filtration and recrystallised from ethanol, yield 1.07g (55%). Crystals were obtained from evaporation of a mixture of methanol/acetone at room temperature. IR (ATR,cm-1): at line % / 1595 (C=N),1680 (C=O). 1H NMR dH (500 MHz, CDCl3, p.p.m) δH: 1.16 (6H, t, C16, 16–H), 2.85 (4H, t, C12, 12–H), 4.05 (4H, q, C15, 15–H), 4.67 (4H, t, C11,11–H), 6.11 (2H, t, C3, 3–H), 6.58 (2H, d, C4,4–H), 6.83 (2H, d, C2, 2–H), 7.11 (4H, s, C9, 9, C10, 10–H) and 8.25 (2H, s, C6, 6–H): 13C NMR (125.75 MHz, CDCl3, p.p.m) δC: 14.29 (C16, 16-), 36.14 (C12, 12-), 44.98 (C11, 11-), 60.62 (C15,15-), 108.85 (C 3, 3-), 119.88 (C2, 2-), 121.57 (C9,8-) and C10,10-), 129.16 and 129.17 to (C4, 4- and C5, 5-), 149.38 (C6, 6-) and 150.02 (C 8, 8-). C=O at 171.12 (C13,13-). ). The positive ES at m/z = 463.7 (M+H)+ (42%) for C26H30N4O4, requires =462.3. The other peaks detected at m/z =405.2 (3%), 361.6 (12%), 317.2 (3%) and 261.4 (3%) correspond to [M-2(CH2CH3)]+, [M-(2(CH2CH3)+CO2)]+, [M-(2CH2CH3+2CO2)]+ and [M-(2CH2CH3+2CO2+2CH2CH2)]+, espectively.
with an mixture (33% ethyl acetate / hexane), yield 0.70 g (70%) of the title compound as a yellow oil product.IR (ATR cm-1): 1660Crystal data, data collection and structure
details are summarized in Table 1.The
was H atom attached to N1 was located in the difference Fourier map and refined isotropically. All other H atoms were placed in calculated positions with d(C—H) = 0.95 Å for aromatic, 0.99 for CH2 and 0.98 Å for CH3 atoms. The Uiso values were constrained to be 1.5Ueq of the for methyl H atoms and 1.2Ueq for the remaining H atoms. A rotating group model was used for the methyl groups.The Schiff base diethyl 3,3'-(2,2'-(1E)-(1,4-phenylenebis(azan-1-yl-1-ylidene))bis (methan-1-yl-1-ylidene)bis(1H-pyrrole-2,1-diyl))dipropanoate was prepared in two steps. The reaction of 1H-pyrrole-2-carbaldehyde with ethyl bromopropanoate resulted in the formation of (2-formyl-1H-pyrrole-1-yl)-propanoate (Koriatopoulou et al. (2008) and Singh & Pal (2010)). The reaction of two moles of the pyrrole ester with p-phenylenediamine gave the title of Schiff-base compound (Yang et al., 2004; Ourari et al., 2013). The compound with molar mass 462.54 g mol-1, crystallizes in monoclinic
with a c12 /c1 and had a calculated density 1.259 g cm-3. The asymetric unit consists of half the molecule, the molecule is completed by inversion symmetry. Infrared spectra indidicates typical absorbance bands of thefunctional -C=N and carbonyl -C=O at 1595 and 1680 cm-1, respectively. The positive ES
of the bis Schiff base showed a peak at m/z = 463.7 (M+H)+, corresponding to C26H30N4O4, for which the required value=462.3. The values distance (1.270Å) observed for (N7-C6) is shorter than (N7-C8) (1.458Å), indicating a double bond order. The distance observed at (1.384Å) for (N1-C5), revealed a resonance is occurred in the pyrrole system between lon pair electron of the nitrogen atom and the pyrrole ring. Other bond lengths and bond angles are within reported values.For the synthesis of dipyrrole Schiff base ligands, see: Meghdadi et al.(2010); Munro et al. (2004). For the synthesis of pyrrole ester precursors, see: Koriatopoulou et al. (2008); Singh & Pal (2010). For the preparation of the title compound, see: Yang et al. (2004); Ourari et al. (2013).
Data collection: CrysAlis PRO (Agilent, 2013); cell
CrysAlis PRO (Agilent, 2013); data reduction: CrysAlis PRO (Agilent, 2013); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015); molecular graphics: OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: OLEX2 (Dolomanov et al., 2009).Fig. 1. A view of the molecular structure of the title compound. Displacement ellipsoids are drawn at the 50% probability level. |
C26H30N4O4 | F(000) = 984 |
Mr = 462.54 | Dx = 1.259 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 21.6153 (10) Å | Cell parameters from 1750 reflections |
b = 8.1227 (4) Å | θ = 3.8–27.5° |
c = 13.9404 (8) Å | µ = 0.09 mm−1 |
β = 94.395 (5)° | T = 150 K |
V = 2440.4 (2) Å3 | Block, clear light colourless |
Z = 4 | 0.4 × 0.3 × 0.3 mm |
Agilent SuperNova (Single source at offset, Atlas) diffractometer | 2900 independent reflections |
Radiation source: SuperNova (Mo) X-ray Source | 1697 reflections with I > 2σ(I) |
Mirror monochromator | Rint = 0.063 |
Detector resolution: 10.3705 pixels mm-1 | θmax = 29.5°, θmin = 2.9° |
ω scans | h = −18→29 |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013) | k = −10→7 |
Tmin = 0.613, Tmax = 1.000 | l = −19→18 |
6592 measured reflections |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.055 | H-atom parameters constrained |
wR(F2) = 0.138 | w = 1/[σ2(Fo2) + (0.0338P)2 + 0.0686P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max < 0.001 |
2900 reflections | Δρmax = 0.22 e Å−3 |
155 parameters | Δρmin = −0.26 e Å−3 |
0 restraints |
C26H30N4O4 | V = 2440.4 (2) Å3 |
Mr = 462.54 | Z = 4 |
Monoclinic, C2/c | Mo Kα radiation |
a = 21.6153 (10) Å | µ = 0.09 mm−1 |
b = 8.1227 (4) Å | T = 150 K |
c = 13.9404 (8) Å | 0.4 × 0.3 × 0.3 mm |
β = 94.395 (5)° |
Agilent SuperNova (Single source at offset, Atlas) diffractometer | 2900 independent reflections |
Absorption correction: multi-scan (CrysAlis PRO; Agilent, 2013) | 1697 reflections with I > 2σ(I) |
Tmin = 0.613, Tmax = 1.000 | Rint = 0.063 |
6592 measured reflections |
R[F2 > 2σ(F2)] = 0.055 | 0 restraints |
wR(F2) = 0.138 | H-atom parameters constrained |
S = 1.10 | Δρmax = 0.22 e Å−3 |
2900 reflections | Δρmin = −0.26 e Å−3 |
155 parameters |
Experimental. CrysAlisPro, Agilent Technologies, Version 1.171.36.28 (release 01-02-2013 CrysAlis171 .NET) (compiled Feb 1 2013,16:14:44) Empirical absorption correction using spherical harmonics, implemented in SCALE3 ABSPACK scaling algorithm. |
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. |
x | y | z | Uiso*/Ueq | ||
O14 | 0.34059 (6) | 0.02364 (17) | 0.24674 (10) | 0.0286 (4) | |
N1 | 0.45878 (7) | 0.29578 (19) | 0.01458 (12) | 0.0225 (4) | |
O17 | 0.41066 (7) | 0.2126 (2) | 0.29870 (11) | 0.0385 (4) | |
N7 | 0.34834 (7) | 0.5212 (2) | 0.01854 (13) | 0.0231 (4) | |
C13 | 0.38269 (9) | 0.1407 (2) | 0.23355 (16) | 0.0240 (5) | |
C6 | 0.37626 (9) | 0.4878 (2) | −0.05699 (16) | 0.0233 (5) | |
H6 | 0.3615 | 0.5387 | −0.1140 | 0.028* | |
C5 | 0.42829 (9) | 0.3787 (2) | −0.06151 (16) | 0.0227 (5) | |
C8 | 0.29823 (9) | 0.6351 (2) | 0.00733 (15) | 0.0213 (5) | |
C9 | 0.29548 (9) | 0.7593 (2) | 0.07499 (16) | 0.0242 (5) | |
H9 | 0.3258 | 0.7654 | 0.1260 | 0.029* | |
C2 | 0.50726 (9) | 0.2115 (3) | −0.01898 (17) | 0.0285 (5) | |
H2 | 0.5353 | 0.1466 | 0.0181 | 0.034* | |
C11 | 0.44300 (9) | 0.2904 (3) | 0.11490 (15) | 0.0248 (5) | |
H11A | 0.4308 | 0.3996 | 0.1345 | 0.030* | |
H11B | 0.4794 | 0.2581 | 0.1556 | 0.030* | |
C12 | 0.39047 (9) | 0.1701 (3) | 0.12900 (15) | 0.0247 (5) | |
H12A | 0.3521 | 0.2135 | 0.0983 | 0.030* | |
H12B | 0.3991 | 0.0663 | 0.0983 | 0.030* | |
C15 | 0.33162 (10) | −0.0179 (3) | 0.34693 (16) | 0.0307 (6) | |
H15A | 0.3205 | 0.0796 | 0.3820 | 0.037* | |
H15B | 0.3694 | −0.0636 | 0.3782 | 0.037* | |
C10 | 0.25193 (9) | 0.6253 (2) | −0.06747 (16) | 0.0244 (5) | |
H10 | 0.2528 | 0.5411 | −0.1126 | 0.029* | |
C4 | 0.45880 (9) | 0.3440 (3) | −0.14264 (17) | 0.0283 (5) | |
H4 | 0.4484 | 0.3843 | −0.2042 | 0.034* | |
C3 | 0.50810 (10) | 0.2377 (3) | −0.11602 (17) | 0.0318 (6) | |
H3 | 0.5361 | 0.1933 | −0.1564 | 0.038* | |
C16 | 0.28000 (11) | −0.1429 (3) | 0.34458 (18) | 0.0412 (6) | |
H16A | 0.2913 | −0.2375 | 0.3085 | 0.062* | |
H16B | 0.2427 | −0.0953 | 0.3147 | 0.062* | |
H16C | 0.2731 | −0.1756 | 0.4091 | 0.062* |
U11 | U22 | U33 | U12 | U13 | U23 | |
O14 | 0.0361 (8) | 0.0298 (9) | 0.0205 (9) | −0.0087 (7) | 0.0052 (7) | −0.0004 (7) |
N1 | 0.0217 (9) | 0.0226 (10) | 0.0236 (10) | 0.0014 (7) | 0.0051 (8) | 0.0034 (8) |
O17 | 0.0397 (9) | 0.0498 (11) | 0.0266 (10) | −0.0165 (8) | 0.0054 (8) | −0.0087 (8) |
N7 | 0.0234 (9) | 0.0209 (9) | 0.0255 (10) | 0.0023 (7) | 0.0057 (8) | −0.0010 (8) |
C13 | 0.0213 (11) | 0.0228 (11) | 0.0283 (13) | −0.0002 (9) | 0.0032 (10) | −0.0042 (10) |
C6 | 0.0258 (11) | 0.0184 (11) | 0.0260 (12) | −0.0029 (8) | 0.0042 (10) | 0.0040 (10) |
C5 | 0.0241 (10) | 0.0189 (11) | 0.0257 (12) | 0.0002 (8) | 0.0064 (9) | 0.0021 (10) |
C8 | 0.0212 (10) | 0.0192 (11) | 0.0242 (12) | 0.0008 (8) | 0.0071 (9) | 0.0028 (10) |
C9 | 0.0209 (10) | 0.0260 (12) | 0.0255 (12) | −0.0006 (9) | 0.0005 (9) | −0.0031 (10) |
C2 | 0.0236 (11) | 0.0255 (12) | 0.0375 (14) | 0.0074 (9) | 0.0106 (10) | 0.0027 (11) |
C11 | 0.0236 (10) | 0.0270 (12) | 0.0239 (12) | 0.0000 (9) | 0.0019 (9) | 0.0010 (10) |
C12 | 0.0262 (11) | 0.0254 (12) | 0.0226 (12) | 0.0010 (9) | 0.0023 (9) | −0.0028 (10) |
C15 | 0.0414 (13) | 0.0290 (13) | 0.0230 (13) | −0.0002 (10) | 0.0102 (11) | 0.0002 (11) |
C10 | 0.0260 (11) | 0.0219 (11) | 0.0257 (13) | 0.0001 (9) | 0.0040 (10) | −0.0070 (10) |
C4 | 0.0323 (12) | 0.0261 (12) | 0.0275 (13) | 0.0012 (9) | 0.0099 (10) | 0.0063 (11) |
C3 | 0.0330 (12) | 0.0293 (13) | 0.0351 (15) | 0.0075 (10) | 0.0153 (11) | 0.0018 (11) |
C16 | 0.0551 (16) | 0.0357 (14) | 0.0347 (15) | −0.0100 (11) | 0.0152 (13) | 0.0024 (12) |
O14—C13 | 1.338 (2) | C2—C3 | 1.371 (3) |
O14—C15 | 1.464 (2) | C11—H11A | 0.9700 |
N1—C5 | 1.381 (3) | C11—H11B | 0.9700 |
N1—C2 | 1.364 (2) | C11—C12 | 1.522 (3) |
N1—C11 | 1.465 (3) | C12—H12A | 0.9700 |
O17—C13 | 1.203 (2) | C12—H12B | 0.9700 |
N7—C6 | 1.282 (2) | C15—H15A | 0.9700 |
N7—C8 | 1.424 (2) | C15—H15B | 0.9700 |
C13—C12 | 1.499 (3) | C15—C16 | 1.507 (3) |
C6—H6 | 0.9300 | C10—C9i | 1.387 (3) |
C6—C5 | 1.437 (3) | C10—H10 | 0.9300 |
C5—C4 | 1.381 (3) | C4—H4 | 0.9300 |
C8—C9 | 1.386 (3) | C4—C3 | 1.399 (3) |
C8—C10 | 1.391 (3) | C3—H3 | 0.9300 |
C9—H9 | 0.9300 | C16—H16A | 0.9600 |
C9—C10i | 1.387 (3) | C16—H16B | 0.9600 |
C2—H2 | 0.9300 | C16—H16C | 0.9600 |
C13—O14—C15 | 115.83 (16) | C12—C11—H11B | 109.2 |
C5—N1—C11 | 127.98 (16) | C13—C12—C11 | 111.61 (17) |
C2—N1—C5 | 108.38 (18) | C13—C12—H12A | 109.3 |
C2—N1—C11 | 123.62 (18) | C13—C12—H12B | 109.3 |
C6—N7—C8 | 116.70 (18) | C11—C12—H12A | 109.3 |
O14—C13—C12 | 112.02 (18) | C11—C12—H12B | 109.3 |
O17—C13—O14 | 123.3 (2) | H12A—C12—H12B | 108.0 |
O17—C13—C12 | 124.69 (18) | O14—C15—H15A | 110.4 |
N7—C6—H6 | 117.1 | O14—C15—H15B | 110.4 |
N7—C6—C5 | 125.9 (2) | O14—C15—C16 | 106.64 (18) |
C5—C6—H6 | 117.1 | H15A—C15—H15B | 108.6 |
N1—C5—C6 | 126.61 (19) | C16—C15—H15A | 110.4 |
N1—C5—C4 | 107.45 (17) | C16—C15—H15B | 110.4 |
C4—C5—C6 | 125.9 (2) | C8—C10—H10 | 119.9 |
C9—C8—N7 | 118.06 (19) | C9i—C10—C8 | 120.20 (18) |
C9—C8—C10 | 119.07 (18) | C9i—C10—H10 | 119.9 |
C10—C8—N7 | 122.86 (18) | C5—C4—H4 | 126.0 |
C8—C9—H9 | 119.6 | C5—C4—C3 | 108.1 (2) |
C8—C9—C10i | 120.71 (19) | C3—C4—H4 | 126.0 |
C10i—C9—H9 | 119.6 | C2—C3—C4 | 106.86 (18) |
N1—C2—H2 | 125.4 | C2—C3—H3 | 126.6 |
N1—C2—C3 | 109.23 (19) | C4—C3—H3 | 126.6 |
C3—C2—H2 | 125.4 | C15—C16—H16A | 109.5 |
N1—C11—H11A | 109.2 | C15—C16—H16B | 109.5 |
N1—C11—H11B | 109.2 | C15—C16—H16C | 109.5 |
N1—C11—C12 | 111.88 (17) | H16A—C16—H16B | 109.5 |
H11A—C11—H11B | 107.9 | H16A—C16—H16C | 109.5 |
C12—C11—H11A | 109.2 | H16B—C16—H16C | 109.5 |
O14—C13—C12—C11 | −174.17 (16) | C5—N1—C11—C12 | 79.5 (2) |
N1—C5—C4—C3 | 0.5 (2) | C5—C4—C3—C2 | −0.8 (2) |
N1—C2—C3—C4 | 0.9 (2) | C8—N7—C6—C5 | 179.01 (17) |
N1—C11—C12—C13 | 169.07 (17) | C9—C8—C10—C9i | 1.3 (3) |
O17—C13—C12—C11 | 5.8 (3) | C2—N1—C5—C6 | −177.15 (19) |
N7—C6—C5—N1 | −2.6 (3) | C2—N1—C5—C4 | 0.0 (2) |
N7—C6—C5—C4 | −179.3 (2) | C2—N1—C11—C12 | −98.6 (2) |
N7—C8—C9—C10i | 179.47 (17) | C11—N1—C5—C6 | 4.5 (3) |
N7—C8—C10—C9i | −179.52 (18) | C11—N1—C5—C4 | −178.28 (18) |
C13—O14—C15—C16 | 176.56 (17) | C11—N1—C2—C3 | 177.83 (18) |
C6—N7—C8—C9 | −134.2 (2) | C15—O14—C13—O17 | −2.2 (3) |
C6—N7—C8—C10 | 46.7 (3) | C15—O14—C13—C12 | 177.75 (16) |
C6—C5—C4—C3 | 177.72 (19) | C10—C8—C9—C10i | −1.4 (3) |
C5—N1—C2—C3 | −0.6 (2) |
Symmetry code: (i) −x+1/2, −y+3/2, −z. |
Experimental details
Crystal data | |
Chemical formula | C26H30N4O4 |
Mr | 462.54 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 150 |
a, b, c (Å) | 21.6153 (10), 8.1227 (4), 13.9404 (8) |
β (°) | 94.395 (5) |
V (Å3) | 2440.4 (2) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.4 × 0.3 × 0.3 |
Data collection | |
Diffractometer | Agilent SuperNova (Single source at offset, Atlas) |
Absorption correction | Multi-scan (CrysAlis PRO; Agilent, 2013) |
Tmin, Tmax | 0.613, 1.000 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6592, 2900, 1697 |
Rint | 0.063 |
(sin θ/λ)max (Å−1) | 0.693 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.055, 0.138, 1.10 |
No. of reflections | 2900 |
No. of parameters | 155 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.22, −0.26 |
Computer programs: CrysAlis PRO (Agilent, 2013), SHELXS97 (Sheldrick, 2008), SHELXL2014 (Sheldrick, 2015), OLEX2 (Dolomanov et al., 2009).
Acknowledgements
The authors would like to thank the `Iraqi Ministry for Higher Education' for providing six months funding for JA's PhD scholarship.
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The Schiff base diethyl 3,3'-(2,2'-(1E)-(1,4-phenylenebis(azan-1-yl-1-ylidene))bis (methan-1-yl-1-ylidene)bis(1H-pyrrole-2,1-diyl))dipropanoate was prepared in two steps. The reaction of 1H-pyrrole-2-carbaldehyde with ethyl bromopropanoate resulted in the formation of (2-formyl-1H-pyrrole-1-yl)-propanoate (Koriatopoulou et al. (2008) and Singh & Pal (2010)). The reaction of two moles of the pyrrole ester with p-phenylenediamine gave the title of Schiff-base compound (Yang et al., 2004; Ourari et al., 2013). The compound with molar mass 462.54 g mol-1, crystallizes in monoclinic crystal structure with a space group c12 /c1 and had a calculated density 1.259 g cm-3. The asymetric unit consists of half the molecule, the molecule is completed by inversion symmetry. Infrared spectra indidicates typical absorbance bands of the
functional -C=N and carbonyl -C=O at 1595 and 1680 cm-1, respectively. The positive ES mass spectrum of the bis Schiff base showed a parent ion peak at m/z = 463.7 (M+H)+, corresponding to C26H30N4O4, for which the required value=462.3. The values distance (1.270Å) observed for (N7-C6) is shorter than (N7-C8) (1.458Å), indicating a double bond order. The distance observed at (1.384Å) for (N1-C5), revealed a resonance is occurred in the pyrrole system between lon pair electron of the nitrogen atom and the pyrrole ring. Other bond lengths and bond angles are within reported values.