Structural and electronic properties of chemically modified fullerenes

ABSTRACT

Chemically modified fullerenes are emerging as an important class of technological materials. This study deals with one such category of modified fullerenes, viz., heterofullerenes. Structure-property relationships of Pd, Ni and N-substituted heterofullerenes were probed using density functional theory calculations. Distortion in spheroid of C${}_{60}$ cage during formation of three different heterofullerenes, viz., C${}_{59}$M, C${}_{56}$N${}_3$M and C${}_{54}$N${}_4$M ($\mathrm{M}=\mathrm{Pd}/\mathrm{Ni}$), was analyzed from DFT optimised geometries and¹³C NMR characterisation. NBO analysis was done to identify the strength of bonds based on their bond orders and coordination of metal M with C and N atoms. Extent of delocalisation of π electrons in terms of aromaticity of C${}_{60}$ after foreign atoms substitution was examined by NICS(0) characterisation. HOMO-LUMO gap, ionisation potential, electron affinity and chemical potential were calculated to obtain insights into the reactivities and stabilities of the heterofullerenes with reference to C${}_{60}$. Amongst C${}_{59}$M, C${}_{56}$N${}_3$M and C${}_{54}$N${}_4$M heterofullerenes, C${}_{56}$N${}_3$M and C${}_{54}$N${}_4$M were concluded to be the most stable and reactive heterofullerenes, respectively.

KEYWORDS:

• Metal-substituted fullerenes
• reactivity
• stability
• computed NMR spectra
• computed IR spectra
• density functional theory

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by Department of Science and Technology of Ministry of Science and Technology, Government of India under Fast-Track Scheme for Young Scientists Programme (SB/FTP/ETA-353-2012).