Synthesis and Study of the Crystal Structure of 2-[(Dipyrrolidin-1-yl)‎ methylene] malononitrile

Abstract EN

This study aims to synthesis 2-[(dipyrrolidin-1-yl)methylene] malononitrile 2 and identify its crystal structure by X-ray diffraction analysis.

2-[(dipyrrolidin-1-yl)methylene] malononitrile was prepared by a direct displacement of the methylthio group (SMe) in the 2-[bis(methylthio)methylene] malononitrile 1 with pyrrolidine as cyclic secondary amine by conjugating addition-elimination reaction under reflux conditions for two hours.

the com-pound was obtained in high yield (80%).

the structure of compound 2-[(dipyrrolidin-1-yl)methylene] malononitrile 2 was identified by performing X-ray diffraction analysis.

suita-ble crystals of compound 2 were grown by slow evaporation of methanol solution of the com-pound.

the compound 2 crystallized in an orthorhombic crystal system with a space group of pbcn.

in the title compound, the two cyanide groups and the two pyrrolidine rings adopted trans configurations across the C2=C3 bond.

the bond lengths and angles of the two pyrroli-dinyl rings in the compound are within the normal range.

the maximum deviation of N5/C2/C3/C4/N5a/C4a is 0.002(1) around C4, and no deviation has been recorded for thefragment N1/N1a/C2/C3 (0.000 (1)°).

the dihedral angle between the pyrrolidine ring andN1/N1a/C2/C3 is 33.06(8)°, and the dihedral angle between the pyrrolidine ring andN5/C2/C3/C4/N5a/C4a is 50.57(7)°.

The crystal packing is stabilized by two intermolecularand one intramolecular C---H…N hydrogen bonds, which form a one-dimensional polymeric chain along the axis.