Unmasking the Optimal Isomers of Ti₂C₈₄: Ti₂C₂@C₈₂ Instead of Ti₂@C₈₄

Abstract

Up to now, the controversies\nover the stable structures of endohedral di-metallofullerenes M₂C<i>_n</i>, whether M₂@C<i>_n</i> or M₂C₂@C_<i>n</i>–2, have continued ceaselessly. Herein, to\ndisclose the optimal structures of Ti₂C₈₄, density\nfunctional theory combined with statistical thermodynamic analysis\nis performed in detail and it turns out that isolated pentagon rule\nC₈₂ with Ti₂C₂ inserted wins overwhelmingly\nand performs close-shell electronic structure after our detailed analysis.\nFurthermore, the stimulation of UV–vis–NIR absorption\nspectra of thermodynamics preferred isomers under polarizable continuum\nmodels shows better accordance to the experimental spectra to reconfirm\nour result again. And ¹³C NMR spectra of three more stable\nisomers are performed for further investigations on geometry structures.\nLast but not least, the electronic structures and various interactions\nof thermodynamically optimum structures are further revealed.