TY - JOUR

T1 - Conformational dualism of dipyridyl-substituted formamidine

AU - Sukhikh, T. S.

AU - Kolybalov, D. S.

AU - Bashirov, D. A.

AU - Gromilov, S. A.

AU - Konchenko, S. N.

N1 - Publisher Copyright: © 2021, Pleiades Publishing, Ltd.

PY - 2021/6

Y1 - 2021/6

N2 - A new polymorph of the β-modification of N,N′-di(pyridin-2-yl)formamidine that is more thermodynamically stable than the known α-modification is obtained. The crystal of β-modification contains hydrogen bonded molecular dimers with a skewed geometry. Therefore, the space group is not centrosymmetric – P42. This geometry is a result of the molecular E-syn,syn conformation in crystals of the β-phase, which differs from the E-anti,syn conformation in the α-phase. The number of crystallographically non-equivalent molecules (8) in the β-modification is unusually large for organic compounds. The structure of the packing is analyzed, and it is shown that the centers of dimers follow the sites of a distorted body-centered cubic pseudo-lattice (Ат ≈ 10 Å, αт = 90°) with a 16 times decreased unit cell volume. Reasons for symmetry violations causing modulations are considered.

AB - A new polymorph of the β-modification of N,N′-di(pyridin-2-yl)formamidine that is more thermodynamically stable than the known α-modification is obtained. The crystal of β-modification contains hydrogen bonded molecular dimers with a skewed geometry. Therefore, the space group is not centrosymmetric – P42. This geometry is a result of the molecular E-syn,syn conformation in crystals of the β-phase, which differs from the E-anti,syn conformation in the α-phase. The number of crystallographically non-equivalent molecules (8) in the β-modification is unusually large for organic compounds. The structure of the packing is analyzed, and it is shown that the centers of dimers follow the sites of a distorted body-centered cubic pseudo-lattice (Ат ≈ 10 Å, αт = 90°) with a 16 times decreased unit cell volume. Reasons for symmetry violations causing modulations are considered.

KW - crystal structure

KW - formamidine

KW - hydrogen bond

KW - polymorph

UR - http://www.scopus.com/inward/record.url?scp=85111124117&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/8407a066-3d5a-3d0c-8136-dd255f978c7f/

U2 - 10.1134/S0022476621060160

DO - 10.1134/S0022476621060160

M3 - Article

AN - SCOPUS:85111124117

VL - 62

SP - 966

EP - 973

JO - Journal of Structural Chemistry

JF - Journal of Structural Chemistry

SN - 0022-4766

IS - 6

ER -