Exploring the Electronic, Optical, and Bioactive Properties for New Modified Fullerenes via Molecular Modeling

Pristine fullerene characters are highly influenced upon surface decoration by COOH, NH2, and Li sets. The electronic, vibrational, and optical properties of pristine and modified fullerenes are well tested using DFT. QSAR descriptors are fulfilled via PM6 interface for proposed fullerenes. Results showed that C60-2Li may compete recent kesterite Cu2ZnGeSe4 solar cell which have band gap range as 1.5∼1.7 eV and efficiency > 14%. The C60-2Li may represent a new row of highly efficient fabricated solar cells. MESP contours found that additive Li possesses a blue shift in Fullerene electronegative behavior towards electrophilic additions whereas additive COOH and NH2 maintain the original nucleophilic additions. Based upon QSAR values, C60-2NH2 is acknowledged as potential bioactive substrate for drug delivery. This paves the way towed multidisciplinary application of the studied fullerene system.

A quantitative approach to nucleophilic organocatalysis

The key steps in most organocatalytic cyclizations are the reactions of electrophiles with nucleophiles. Their rates can be calculated by the linear free-energy relationship log k(20 °C) = s N(E + N), where electrophiles are characterized by one parameter (E) and nucleophiles are characterized by the solvent-dependent nucleophilicity (N) and sensitivity (s N) parameters. Electrophilicity parameters in the range –10 < E < –5 were determined for iminium ions derived from cinnamaldehyde and common organocatalysts, such as pyrrolidines and imidazolidinones, by studying the rates of their reactions with reference nucleophiles. Iminium activated reactions of α,β-unsaturated aldehydes can, therefore, be expected to proceed with nucleophiles of 2 < N < 14, because such nucleophiles are strong enough to react with iminium ions but weak enough not to react with their precursor aldehydes. With the N parameters of enamines derived from phenylacetaldehyde and MacMillan’s imidazolidinones one can rationalize why only strong electrophiles, such as stabilized carbenium ions (–8 < E < –2) or hexachlorocyclohexadienone (E = –6.75), are suitable electrophiles for enamine activated reactions with imidazolidinones. Several mechanistic controversies concerning iminium and enamine activated reactions could thus be settled by studying the reactivities of independently synthesized intermediates. Kinetic investigations of the reactions of N-heterocyclic carbenes (NHCs) with benzhydrylium ions showed that they have similar nucleophilicities to common organocatalysts (e.g., PPh3, DMAP, DABCO) but are much stronger (100–200 kJ mol–1) Lewis bases. While structurally analogous imidazolylidenes and imidazolidinylidenes have comparable nucleophilicities and Lewis basicities, the corresponding deoxy Breslow intermediates differ dramatically in reactivity. The thousand-fold higher nucleophilicity of 2-benzylidene-imidazoline relative to 2-benzylidene-imidazolidine is explained by the gain of aromaticity during electrophilic additions to the imidazoline derivatives. O-Methylated Breslow intermediates are a hundred-fold less nucleophilic than deoxy Breslow intermediates.