Theoretical investigation on homoleptic Yttrium tri-guanidinates

The electronic and molecular structures of the homoleptic Yttrium tris-guanidinates complexes Y[(NiPr)2CNR1R2]3, [R1 = R2 = Me, Et and iPr] have been investigated employing DFT calculations in order to understand the structures, bonding and energies of the interactions between Yttrium metal and guanidinate ligands. The effect of the substitution on nitrogen position of guanidinate in these complexes has been also investigated employing DFT and TDDFT calculations for six kinds of models obtained by alternative substitution of alkyl on nitrogen of the guanidinate ligands. The results reveal that the substitution position plays a crucial role in the geometric structure by affecting the torsion angle and the HOMO–LUMO transitions. The energy decomposition analysis indicates a majority of ionic bonding in all systems; the exception is in the M4 (Y[(NYR)2CNCR1R2]3; R = Et and R1 = R2 = H) which present a significant degree of covalency.