Crystal structures ofN-(pyridin-2-ylmethyl)pyrazine-2-carboxamide (monoclinic polymorph) andN-(pyridin-4-ylmethyl)pyrazine-2-carboxamide

Abstract

The title compounds, C 11 H 10 N 4 O (HL1) and C 11 H 10 N 4 O (HL2), are pyridine 2-ylmethyl and 4-ylmethyl derivatives, respectively, of pyrazine-2-carboxamide. HL1 was measured at 153 K and crystallized in the monoclinic space group P2 1 /c with Z = 4. There has been a report of the same structure measured at room temperature but assumed to crystallize in the triclinic space group P1 with Z = 4 [Sasan et al. (2008). Monatsh. Chem. 139,[773][774][775][776][777][778][779][780]. In HL1, the pyridine ring is inclined to the pyrazine ring by 61.34 (6) , while in HL2 this dihedral angle is 84.33 (12) . In both molecules, there is a short N-HÁ Á ÁN interaction involving the pyrazine carboxamide unit. In the crystal of HL1, molecules are linked by N-HÁ Á ÁN hydrogen bonds, forming inversion dimers with an R 2 2 (10) ring motif. The dimers are linked via bifurcated-acceptor C-HÁ Á ÁO hydrogen bonds, forming sheets lying parallel to (102). The sheets are linked via C-HÁ Á ÁN hydrogen bonds, forming a three-dimensional structure. In the crystal of HL2, molecules are linked by N-HÁ Á ÁN and C-HÁ Á ÁN hydrogen bonds to form chains propagating along [010]. The chains are linked via C-HÁ Á ÁO hydrogen bonds, forming sheets lying parallel to (100). Within the sheets there areinteractions involving neighbouring pyrazine rings [inter-centroid distance = 3.711 (15) Å ]. Adjacent sheets are linked via parallel slipped -interactions involving inversion-related pyridine rings [inter-centroid distance = 3.6395 (17) Å ], forming a three-dimensional structure. Chemical contextThe title compounds form part of a series of ligands synthesized in order to study their coordination chemistry with 3d transition metals (Cati, 2002).They have been used to construct coordination polymers and multi-nuclear compounds, and to study their magnetic ISSN 1600-5368 properties (Cati et al., 2004). Similar ligands have been synthesized by other groups who have studied, for example, the magnetic properties of some copper(II) complexes (Hausmann et al., 2003;Kingele et al., 2007). Structural commentaryThe molecular structure of ligand HL1 is illustrated in Fig. 1. HL1 was measured at 153 K and crystallized in the monoclinic space group P2 1 /c with Z = 4. The angle is 91. 461 (11) and the systematic absences, the R int value (0.0348) and the successful refinement {R1 [I > 2(I)] = 0.0319} clearly show that at 153 K the space group is monoclinic P2 1 /c. The same structure measured at room temperature was reported to crystallize in the triclinic space group P1 with Z = 4 (Sasan et al., 2008). However, the three cell angles are close 90 (2) [ = 91.802 (6), = 89.834 (7), = 91.845 (6) ] and the crystal used was a very narrow needle. The final R1 [I > 2(I)] factor was rather high at 0.0699, hence it is possible that the choice of crystal system and space group are incorrect. However, this could not be confirmed when analysing the coordinates using the AddSymm routine in PLATON (Spek, 2009).In the molecule of HL1 there is a short N-HÁ Á ÁN hydrogen ...

N-(Pyrazin-2-yl)adamantane-1-carboxamide

“…The geometries of the pyrazine ring and the adamantane data reports substituent are typical and the C-C and C-N bond lengths are normal and in good agreement with the average literature values (Allen, 2002) and with those of closely related structures (e.g. Cati & Stoeckli-Evans, 2014;Wang & Stoeckli-Evans, 2016;SiMa, 2009;Zheng & Wang, 2009). In the crystal, molecules of the title compound form zigzag chains in the [001] direction through an N3-H3AÁ Á ÁO1 i hydrogen bond [symmetry code: (i) x, Ày, z À 1 2 ] (Table 1).…”

Synthesis, FTIR and Electronic Spectra Studies of Metal (II) Complexes of Pyrazine-2-Carboxylic Acid Derivative

“…A dark brown solid (PYPC1) was formed on cooling at room temperature and recrystallize from ethanol to form a white precipitate (PYPC2) with colourless crystals [6].…”

Crystal structure of poly[[(acetato-κO){μ3-N-[(pyridin-4-yl)methyl]pyrazine-2-carboxamidato-κ4N:N1,N2:N4]copper(II)] dihydrate]: a metal–organic framework (MOF)

“…The ligand N-[(pyridin-4-yl)methyl]pyrazine-2-carboxamide (HL) is one of a series of ligands which were synthesized in order to study their coordination behaviour towards first-row transition metals (Cati, 2002;Cati et al, 2004;Cati & Stoeckli-Evans, 2014). HL is expected to coordinate in a bidentate and possibly a monodentate manner, with eventual bridging of metal atoms to construct two-or three-dimensional networks.…”

“…The title compound, CuL, is a copper acetate complex of the ligand N-[(pyridin-4-yl)methyl]pyrazine-2-carboxamide (HL) ISSN 1600-5368 [Cati & Stoeckli-Evans, 2014]. In complex CuL the ligand coordinates in a bidentate and a bis-monodentate manner, so bridging three equivalent copper atoms (Fig.…”