Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536801005153/bt6028sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536801005153/bt6028Isup2.hkl |
CCDC reference: 165638
The title compound was synthesized by the reaction of 1,2,4,5-benzenetetramine and 2,2'-pyridyl in a 1:2 molar ratio. Single crystals suitable for X-ray diffraction were obtained by slow diffusion of diethyl ether into a CH2Cl2/CH3OH solution of the compound. The product was characterized by NMR and mass spectrometry, giving results consistent with those in the literature (Rillema & Mack, 1982).
Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998).
Fig. 1. The molecular structure of (I) showing 30% probability displacement ellipsoids. H atoms have been omitted. |
C30H18N8 | F(000) = 508 |
Mr = 490.52 | Dx = 1.373 Mg m−3 |
Monoclinic, P2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 15.061 (5) Å | Cell parameters from 4465 reflections |
b = 6.2184 (19) Å | θ = 1.5–25.0° |
c = 13.908 (4) Å | µ = 0.09 mm−1 |
β = 114.398 (5)° | T = 298 K |
V = 1186.3 (6) Å3 | Prism, yellow |
Z = 2 | 0.20 × 0.20 × 0.15 mm |
Bruker SMART 1000 diffractometer | 1217 reflections with I > 2σ(I) |
ω scans | Rint = 0.035 |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | θmax = 25.0° |
Tmin = 0.983, Tmax = 0.987 | h = −17→17 |
4515 measured reflections | k = −3→7 |
2046 independent reflections | l = −16→16 |
Refinement on F2 | w = 1/[σ2(Fo2) + (0.0466P)2] where P = (Fo2 + 2Fc2)/3 |
R[F2 > 2σ(F2)] = 0.041 | (Δ/σ)max = 0.008 |
wR(F2) = 0.104 | Δρmax = 0.16 e Å−3 |
S = 0.94 | Δρmin = −0.15 e Å−3 |
2046 reflections | Extinction correction: SHELXL97 |
173 parameters | Extinction coefficient: 0.0092 (15) |
H-atom parameters constrained |
C30H18N8 | V = 1186.3 (6) Å3 |
Mr = 490.52 | Z = 2 |
Monoclinic, P2/c | Mo Kα radiation |
a = 15.061 (5) Å | µ = 0.09 mm−1 |
b = 6.2184 (19) Å | T = 298 K |
c = 13.908 (4) Å | 0.20 × 0.20 × 0.15 mm |
β = 114.398 (5)° |
Bruker SMART 1000 diffractometer | 2046 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1217 reflections with I > 2σ(I) |
Tmin = 0.983, Tmax = 0.987 | Rint = 0.035 |
4515 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 173 parameters |
wR(F2) = 0.104 | H-atom parameters constrained |
S = 0.94 | Δρmax = 0.16 e Å−3 |
2046 reflections | Δρmin = −0.15 e Å−3 |
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. Full-MATRIX |
x | y | z | Uiso*/Ueq | ||
N1 | 0.24555 (13) | 0.7240 (3) | 0.07158 (14) | 0.0461 (5) | |
N2 | 0.42174 (12) | 0.7179 (3) | 0.33148 (13) | 0.0422 (5) | |
N3 | 0.31210 (11) | 1.0697 (3) | 0.34939 (13) | 0.0409 (5) | |
N4 | 0.11787 (13) | 0.7647 (3) | 0.19029 (14) | 0.0488 (5) | |
C1 | 0.22019 (16) | 0.6088 (4) | −0.01714 (18) | 0.0504 (6) | |
H3A | 0.1816 | 0.6746 | −0.0808 | 0.060* | |
C2 | 0.24769 (18) | 0.4002 (5) | −0.0196 (2) | 0.0585 (7) | |
H2A | 0.2267 | 0.3259 | −0.0832 | 0.070* | |
C3 | 0.3069 (2) | 0.3017 (4) | 0.0735 (2) | 0.0620 (7) | |
H1A | 0.3267 | 0.1598 | 0.0741 | 0.074* | |
C4 | 0.33617 (17) | 0.4181 (4) | 0.16537 (18) | 0.0500 (6) | |
H4A | 0.3780 | 0.3577 | 0.2293 | 0.060* | |
C5 | 0.30255 (14) | 0.6264 (3) | 0.16148 (16) | 0.0376 (5) | |
C6 | 0.33458 (14) | 0.7584 (3) | 0.25939 (16) | 0.0378 (5) | |
C7 | 0.27509 (14) | 0.9293 (3) | 0.27320 (15) | 0.0364 (5) | |
C8 | 0.16811 (14) | 0.9489 (4) | 0.20992 (15) | 0.0386 (5) | |
C9 | 0.12431 (16) | 1.1480 (4) | 0.18140 (17) | 0.0501 (6) | |
H9A | 0.1614 | 1.2732 | 0.1980 | 0.060* | |
C10 | 0.02475 (17) | 1.1561 (4) | 0.1280 (2) | 0.0642 (7) | |
H12A | −0.0064 | 1.2878 | 0.1063 | 0.077* | |
C11 | −0.02855 (17) | 0.9704 (4) | 0.1066 (2) | 0.0655 (8) | |
H11A | −0.0961 | 0.9726 | 0.0706 | 0.079* | |
C12 | 0.02110 (17) | 0.7812 (4) | 0.1400 (2) | 0.0585 (7) | |
H10A | −0.0152 | 0.6550 | 0.1268 | 0.070* | |
C13 | 0.45943 (14) | 0.8533 (3) | 0.41707 (16) | 0.0387 (5) | |
C14 | 0.40723 (14) | 1.0411 (4) | 0.42217 (16) | 0.0378 (5) | |
C15 | 0.44856 (15) | 1.1859 (4) | 0.50402 (16) | 0.0427 (6) | |
H15A | 0.4148 | 1.3096 | 0.5063 | 0.051* |
U11 | U22 | U33 | U12 | U13 | U23 | |
N1 | 0.0385 (10) | 0.0572 (13) | 0.0387 (11) | −0.0036 (9) | 0.0120 (9) | −0.0078 (10) |
N2 | 0.0356 (10) | 0.0469 (11) | 0.0392 (10) | 0.0004 (8) | 0.0105 (8) | −0.0086 (9) |
N3 | 0.0320 (10) | 0.0466 (12) | 0.0383 (10) | 0.0033 (8) | 0.0087 (8) | −0.0039 (9) |
N4 | 0.0370 (11) | 0.0488 (13) | 0.0573 (12) | −0.0049 (9) | 0.0159 (9) | −0.0058 (10) |
C1 | 0.0370 (13) | 0.0727 (18) | 0.0404 (13) | −0.0069 (12) | 0.0149 (11) | −0.0096 (13) |
C2 | 0.0544 (16) | 0.0723 (19) | 0.0537 (16) | −0.0207 (14) | 0.0273 (13) | −0.0262 (15) |
C3 | 0.0794 (19) | 0.0459 (16) | 0.0686 (18) | −0.0044 (14) | 0.0386 (16) | −0.0163 (15) |
C4 | 0.0574 (15) | 0.0424 (15) | 0.0500 (15) | 0.0001 (12) | 0.0220 (12) | −0.0011 (12) |
C5 | 0.0321 (11) | 0.0428 (13) | 0.0385 (12) | −0.0057 (10) | 0.0151 (10) | −0.0057 (10) |
C6 | 0.0325 (12) | 0.0426 (13) | 0.0370 (12) | −0.0015 (10) | 0.0131 (10) | −0.0021 (10) |
C7 | 0.0347 (11) | 0.0401 (13) | 0.0323 (11) | −0.0012 (10) | 0.0118 (9) | −0.0004 (10) |
C8 | 0.0324 (12) | 0.0439 (14) | 0.0370 (12) | 0.0006 (11) | 0.0119 (10) | −0.0041 (10) |
C9 | 0.0357 (13) | 0.0449 (15) | 0.0590 (15) | −0.0013 (11) | 0.0090 (11) | −0.0030 (12) |
C10 | 0.0413 (15) | 0.0538 (17) | 0.0803 (19) | 0.0088 (13) | 0.0078 (13) | 0.0002 (14) |
C11 | 0.0305 (13) | 0.0638 (19) | 0.086 (2) | 0.0004 (13) | 0.0083 (12) | −0.0091 (15) |
C12 | 0.0390 (15) | 0.0520 (16) | 0.0778 (18) | −0.0074 (12) | 0.0174 (13) | −0.0116 (14) |
C13 | 0.0321 (12) | 0.0432 (13) | 0.0387 (12) | −0.0011 (10) | 0.0123 (10) | −0.0053 (10) |
C14 | 0.0296 (11) | 0.0433 (13) | 0.0384 (12) | 0.0024 (10) | 0.0117 (10) | −0.0019 (10) |
C15 | 0.0340 (12) | 0.0431 (14) | 0.0452 (13) | 0.0063 (10) | 0.0106 (10) | −0.0084 (11) |
N1—C5 | 1.335 (3) | C5—C6 | 1.489 (3) |
N1—C1 | 1.339 (3) | C6—C7 | 1.453 (3) |
N2—C6 | 1.306 (3) | C7—C8 | 1.488 (3) |
N2—C13 | 1.375 (2) | C8—C9 | 1.382 (3) |
N3—C7 | 1.307 (3) | C9—C10 | 1.372 (3) |
N3—C14 | 1.382 (2) | C10—C11 | 1.367 (4) |
N4—C12 | 1.335 (3) | C11—C12 | 1.369 (3) |
N4—C8 | 1.338 (3) | C13—C15i | 1.388 (3) |
C1—C2 | 1.367 (4) | C13—C14 | 1.426 (3) |
C2—C3 | 1.376 (3) | C14—C15 | 1.382 (3) |
C3—C4 | 1.374 (3) | C15—C13i | 1.388 (3) |
C4—C5 | 1.384 (3) | ||
C5—N1—C1 | 116.6 (2) | C6—C7—C8 | 123.91 (18) |
C6—N2—C13 | 118.11 (18) | N4—C8—C9 | 123.10 (19) |
C7—N3—C14 | 118.25 (18) | N4—C8—C7 | 115.70 (19) |
C12—N4—C8 | 116.4 (2) | C9—C8—C7 | 121.01 (19) |
N1—C1—C2 | 123.9 (2) | C10—C9—C8 | 118.3 (2) |
C1—C2—C3 | 119.0 (2) | C11—C10—C9 | 119.9 (2) |
C4—C3—C2 | 118.4 (2) | C10—C11—C12 | 117.6 (2) |
C3—C4—C5 | 119.0 (2) | N4—C12—C11 | 124.7 (2) |
N1—C5—C4 | 123.1 (2) | N2—C13—C15i | 119.82 (19) |
N1—C5—C6 | 116.48 (19) | N2—C13—C14 | 120.39 (18) |
C4—C5—C6 | 120.3 (2) | C15i—C13—C14 | 119.69 (19) |
N2—C6—C7 | 121.26 (19) | C15—C14—N3 | 119.82 (19) |
N2—C6—C5 | 116.03 (19) | C15—C14—C13 | 120.31 (18) |
C7—C6—C5 | 122.65 (18) | N3—C14—C13 | 119.69 (19) |
N3—C7—C6 | 121.07 (19) | C14—C15—C13i | 120.0 (2) |
N3—C7—C8 | 114.82 (18) |
Symmetry code: (i) −x+1, −y+2, −z+1. |
Experimental details
Crystal data | |
Chemical formula | C30H18N8 |
Mr | 490.52 |
Crystal system, space group | Monoclinic, P2/c |
Temperature (K) | 298 |
a, b, c (Å) | 15.061 (5), 6.2184 (19), 13.908 (4) |
β (°) | 114.398 (5) |
V (Å3) | 1186.3 (6) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.09 |
Crystal size (mm) | 0.20 × 0.20 × 0.15 |
Data collection | |
Diffractometer | Bruker SMART 1000 diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.983, 0.987 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4515, 2046, 1217 |
Rint | 0.035 |
(sin θ/λ)max (Å−1) | 0.595 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.104, 0.94 |
No. of reflections | 2046 |
No. of parameters | 173 |
No. of restraints | ? |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.16, −0.15 |
Computer programs: SMART (Bruker, 1998), SMART, SAINT (Bruker, 1998), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998).
N1—C5 | 1.335 (3) | N3—C7 | 1.307 (3) |
N1—C1 | 1.339 (3) | N3—C14 | 1.382 (2) |
N2—C6 | 1.306 (3) | N4—C12 | 1.335 (3) |
N2—C13 | 1.375 (2) | N4—C8 | 1.338 (3) |
C5—N1—C1 | 116.6 (2) | N2—C6—C5 | 116.03 (19) |
C6—N2—C13 | 118.11 (18) | N3—C7—C8 | 114.82 (18) |
C7—N3—C14 | 118.25 (18) | N4—C8—C9 | 123.10 (19) |
C12—N4—C8 | 116.4 (2) | N4—C8—C7 | 115.70 (19) |
N1—C5—C6 | 116.48 (19) | C15—C14—N3 | 119.82 (19) |
Bridging polypyridyl ligands have been actively studied in recent years as building blocks for supramolecular assemblies (Hagrman et al., 1999; Leininger et al., 2000). Some of the polypyridyl compounds are of considerable interest because of their potential functionality of their metal complexes as photonic molecular devices (Eggleston et al., 1997; Miller et al., 1999) and DNA probes (Yam et al., 1995; Holmlin et al., 1999). Incorporating a ligand with two chelating sites into the coordination sphere allows systematic construction of large supramolecular assemblies capable of acting as antennae in energy-conversion schemes, where the photochemical and redox properties of the complexes are strongly dependent on the nature of the ligands (Waterland et al., 2000). Since the stereochemistry of such compounds is so useful in the rational design of new functional materials, we report herein the crystal structure of 2,3,7,8-tetrakis(2-pyridyl)pyrazino[2,3-g]quinoxaline, (I). In this structure, there is half a molecule in the asymmetric unit and the other half is inversion related.
A perspective view of the title compound including the atomic numbering scheme is shown in Fig. 1. It consists of a pyrazino[2,3-g]quinoxaline system substituted with four pyridine rings. The two independent pyridine rings are not coplanar with each other nor with the pyrazine ring due to steric clashes between the H atoms of the pyridine rings. The torsion angle between the C—C bonds connecting the pyridine rings to the pyrazine ring (C5—C6—C7—C8) is 19.4 (3)°. The pyrazine ring makes dihedral angles of 43.6 (3) and 33.0 (2)° with the two independent pyridine rings. The dihedral angle between the two pyridine rings is 58.3 (3)° and their N atoms face each other. In the central C6 ring and the pyrazine ring, the mean deviation of any atom from the best-fit planes describing them are 0.0046 (1) and 0.0369 (3) Å, respectively. Furthermore, all non-H atoms in the pyrazino[2,3-g]quinoxaline system lie in a rough plane: the mean deviation of any non-H atoms from the best-fit plane describing them is 0.0522 (2) Å. These distortions from planarity in the molecule are similar to its analogues (Rasmussen et al., 1990; Du et al., 2001). The C—N bond distances lie in the range 1.306 (3)–1.382 (2) Å and are remarkably shorter than normal C—N single bonds (1.47 Å; Sasada, 1984) and longer than the C═N double-bond distance (1.28 Å; Wang et al., 1998) due to the π-electron repulsion of the system. The C—C bond distances are in the range 1.367 (4)–1.489 (3) Å and all the bond angles are about 120°, falling within normal limits. There are no hydrogen bonds or π–π-stacking interactions between different molecules in the unit cell.