Crystal structure of 2-(2′-pyridyl)imidazole, C8H7N3

Abstract

C 8H7N3,t riclinic, P1 (no. 2), a =13.452(5) Å, b =14.016(5) Å, c =17.086(6) Å, a =73.38(2)°, b =71.56(2)°, g =75.12(2)°, Source of material Experimental detailsThe crystal diffracted only till 2q =46.5°.Each refl. is measured more than 10 times (78595 measured refl.). The data have been collected at 120 Ktohave the highest possible 2q max .All the hydrogen atoms were localized by difference Fourier maps and refined. DiscussionThe title molecule 2-(2'-pyridyl)imidazole (py-imH) has been widely used as ligand in coordination chemistry [1][2][3][4] [14,15]. It is also known to yield to iron(II) complexes exhibiting spin crossover behaviour in solution [16,17] as well as in the solid state [18][19][20][21][22]. Yet its crystal structure had not been determined. The asymmetric part of the unit cell contains eight organic molecules which is rather rare. They differ by their conformation as the eight independent molecules show significant differences in the dihedral angle N2-C3-C4-C5 (j)b etween aromatic rings. A range of j is observed between 1(1)°to 17(1)°.A ll the N-H groups are involved in N-H···Nhydrogen bonds, four of which are Hb onds between molecules of the same asymmetric unit. Some p-p and C-H···p interactions contribute also to the building of the observed dense supramolecular network.

Crystal structure of tetraaqua[2-(pyridin-2-yl)-1H-imidazole-κ2N2,N3]iron(II) sulfate

“…The torsion angles within the approximately planar five-membered chelate ring of (I) vary from 0.6 (3) to À5.2 (2) and reflect a more pronounced deviation from planarity in comparison with the dmbpy Fe II complex that exhibits a maximal torsion angle of 2.0 (3) . The dihedral angle of 5.5 (1) between the aromatic rings of the pyim ligand is within the range of the values reported for the eight independent molecules in the crystal structure of the non-coordinating ligand [1(1) to 17 (1) ; Tinant et al, 2010]. In the present complex, all four Fe-O bond lengths, ranging from 2.1191 (18) to 2.1340 (17) Å , are longer than the corresponding ones in the [Fe(dmbpy)(H 2 O) 4 ]SO 4 complex, which range from 2.079 (2) to 2.110 (2) Å .…”

Role of Protonation and Isomerism in the Supramolecular Architectures of Heteroaryl-2-imidazole Compounds: Crystal Packing Patterns and Energetics

“…A polymorph of Himpy in space group P1̅ with eight independent molecules is already reported. 50 The most important structural features in Himpy are mainly related to bond angles of the imi rings C2−N1−C5 In this manner, one can see that all these structural parameters agree with expected values for neutral conformations.…”

“…Himpy crystallizes in the orthorhombic space group Ccc 2, with four molecules per asymmetric unit, corresponding therefore to four different conformers (A, B, C, and D) of Himpy molecules. A polymorph of Himpy in space group P 1̅ with eight independent molecules is already reported . The most important structural features in Himpy are mainly related to bond angles of the imi rings C2–N1–C5 (A: 107.21(4)°, B: 106.81(7)°, C: 107.25(4)°, D: 106.98(7)°) and C2–N3–C4 (A:105.27(4)°, B:105.01(7)°, C:104.95(4)°, D:104.90(7)°).…”