Experimental electron-density study of 4-cyanoimidazolium-5-olate at 120 K

This paper presents an analysis of the electron density in 4-cyanoimidazolium-5-olate, determined by the rigid pseudoatom model from accurate X-ray data measured at 120 K. A comparison of the electrostatic potential between experiment and theory is given for the isolated molecule. The results confirm the typical mesoionic electron distribution of the title compound and the presence of three hydrogen bonds in the crystal structure. The atomic charges and molecular dipole moment derived hem the ab initio Hartree-Fock method are close to those obtained from the multipole model, which includes the kappa radial parameters. Electrostatic energies are also calculated for hydrogen bonding and molecular stacking interactions.