Diradical character and second hyperpolarizability of multidecker inverse sandwich complexes of Mg and Ca

- Multidecker inverse sandwich compounds of Mg and Ca are fairly stable and possess diradical character.
- The stability increases in the order of increasing size of metal complexes.
- Spin flip from open-shell singlet to triplet occurs as the size of complex increases.
- Large second hyperpolarizability is predicted for metal complexes having intermediate diradical character.
- The second hyperpolarizability of triplet complexes increase with increasing size of the complex.