Why does disubstituted hexamolybdate with arylimido prefer to form an orthogonal derivative? Analysis of stability, bonding character, and electronic properties on molybdate derivatives by Density Functional Theory (DFT) study

Abstract

The bonding character of arylimido molybdate derivatives has been investigated, using density functional theory (DFT). The natural bond orbital analysis reveals that the Mo≡N triple bond in the arylimido molybdate derivatives is comprised of a σ-bond and two π-bonds. The energy analysis of 2,6-dimethylaniline disubstituted molybdate derivatives [Mo 6O17R2]2- (where R = 2,6-dimethylaniline group) has been performed. The results show that orthogonal [Mo6O17R2]2- is more stable than diagonal [Mo6O17R2]2-. The bonding capability of the Mo6O17R fragment with arylimido group R is strong for orthogonal [Mo6O17R2] 2-. 2,6-Dimethylaniline disubstituted hexamolybdate derivative prefers to form an orthogonal derivative. The analysis of geometrical and electronic properties provides further support. The arylimido effectively modifies the occupied molecular orbitals and extends its organic π-electrons to the polyoxometalate skeleton. The major contributors to the highest occupied molecular orbital (HOMO) are p orbitals centered on the C atoms and N atoms, and dyz orbitals centered on Mo atoms linked with the N atom of the organoimido group. The present investigation provides important insight into polyanion-organoimido interactions.