Experimental Charge Density Analysis of p-O2NC6F4CNSSN•, a Dithiadiazolyl Molecular Radical

Abstract

The experimental electron density distribution of p-O₂NC₆F₄CNSSN^•, a dithiadiazolyl radical, has been determined from a high-resolution X-ray diffraction experiment at 100 K. The atomic charges obtained according to Bader partitioning through integration over the atomic basins reveal charge transfer from the –CNSSN ring to the –NO₂ moiety. There is an electric polarization of the molecule along the 2-fold axis in the [110] direction, which is also a symmetry axis of the molecule. Analysis of the topological properties of the electron density has evidenced a range of interactions. The presence of a bond critical point along the S···N contacts previously identified as significant for communication between spins confirms an intermolecular interaction between these spin-bearing atoms. Particular attention has been given to the charge density spatial orientation around the sulfur and nitrogen atoms because of the previously identified role of these atoms in the appearance of ferromagnetism at very low temperatures.

A high-resolution X-ray diffraction experiment on an organic ferromagnet has allowed a detailed analysis of the charge density in this molecule. This has confirmed through experiment that the orthogonal orientation of the charge density around the S and N atoms favors ferromagnetic interactions through the crystal structure of this material.