Structural, electronic and magnetic properties of 8-hydroxyquinoline-based small molecules TMQx (TM=Cr, Mn, Fe, Co, Ni, Cu, Zn, and x=2 or 3)

• The properties of 8-hydroxyquinoline-based small molecules are systemically studied.
• The TMQ2 molecules have more symmetrical structures than the TMQ3 molecules.
• The magnetic moment adopts integer number for all TMQ2 and TMQ3 molecules.
• The magnetism can be explained by the crystal field theory.

The structural, electronic and magnetic properties of 8-hydroxyquinoline-based small molecules TMQx (TM=Cr, Mn, Fe, Co, Ni, Cu and Zn, and x=2 or 3) are systemically studied from first principles. These small molecules are spin-polarized semiconductors except for NiQ2, ZnQ2, and CoQ3. For TMQ2, the magnetic moments can be expressed as 8-nµB (n is the number of 3d electrons of TM ions. For Mn, Fe, Co, and Ni, n=5, 6, 7, and 8 respectively) and 10-nµB (n=9 and 10 for Cu and Zn, respectively). For TMQ3, the magnetic moments can be expressed as 6-nµB (n=3, 4, 5, 6 for Cr, Mn, Fe, and Co, respectively). The magnetism can be explained by the spin-polarized filling of splitting d orbitals on the basis of the crystal field theory. This provides theoretical insight for better understanding of 8-hydorquinoline-based complexes (TMQx).

The magnetic moments for all 8-hydroxyquinoline-based small molecules adopt integer numbers; this can be explained in a simple framework on the basis of the crystal field theory.Figure optionsDownload as PowerPoint slide