Investigation into the molecular structure, electronic properties, and energetic stability of endohedral (TM@C 20 ) and exohedral (TM-C 20 ) metallofullerene derivatives of C 20 : TM = Group 11 and 12 transition metal atoms/ions

Investigation into the molecular structure and energetic stability of endohedral and exohedral metallofullerene derivatives of C24

“…In fact, the neutral TM‐C 24 exohedral derivatives energetically prefer to exist in the lower spin‐state for all Group 11 (the 0:2 state) and group 12 (the 0:1 state) metals and all of the charged complexes favor the higher spin‐state, with the exception of the Cu‐C 24 1+ singlet‐state complex that is predicted to be more stable than the triplet‐state by 0.21 eV. The favorability of the lower spin‐state for the neutral exohedral derivatives is generally consistent with similar results reported for TM‐C 20 ; however, that is not the case for the charged complexes. The charged TM‐C 24 complexes all prefer the higher spin‐state, with the noted above exception, whereas all of the charged TM‐C 20 systems favor the lower spin‐state.…”

“…This lower spin‐state favorability of the C 24 endohedral derivatives is consistent with what was reported for the comparable C 20 endohedrals and the neutral Cu and Zn derivatives . For those metal‐endohedral derivatives that converged for C 20 , only the Cu@C 20 1+ triplet and the Zn@C 20 2+ triplet differs from the charge:spin‐state observed in the comparative C 24 derivatives . Of the energetically optimized molecular complexes, the Cu@C 24 1+ , Zn@C 24 2+ , and Cd@C 24 2+ have the potential to be characterized by isoenergetic spin‐states, in which the spin‐state partners of the ions 0.11 eV or less.…”

“…Similarly, Group 12 endohedrals transfer approximately 1.70e of charge to the carbon cage; a 70% increase in charge transferred relative to the Group 11 endohedral complexes. A comparable result was obtained in the analysis of the Group 11 and Group 12 endohedral complexes of C 20 …”

“…The bonding orbitals for the neutral species lie between 0.81 and 1.29 eV below the HOMO, and the bonding orbitals for the +2‐charged ions lie approximately 1.4 eV below the HOMO for each of the group 12 exohedral derivatives. The similarity between the bonding frontier orbitals between the Group 11 and Group 12 C 24 exohedral derivatives is distinctly different than what was observed for the comparative C 20 derivatives . In the case of the C 20 derivatives, the bonding frontier orbital varied from not only Group 11 to Group 12 metals but also between the oxidation states of the same metal.…”

“…Intrigued by assessing both the endohedral and exohedral properties, along with the assessment of noble‐metal metallofullerenes, this article builds upon our previous work with C 20 derivatives and reports the computational study and a comparative study between the endohedral (TM@C 24 ) and exohedral (TM‐C 24 ) metallofullerene derivatives. The TMs incorporated into this investigation are Group 11 (Cu, Ag, and Au) and Group 12 (Zn, Cd, and Hg) metal atoms in various oxidation and spin‐states.…”