Artur R. Tulyabaev

How reliable are GIAO calculations of 1H and 13C NMR chemical shifts? A statistical analysis and empirical corrections at DFT (PBE/3z) level.

Reliability of calculated 1H and 13C NMR chemical shifts for various classes of organic compounds obtained with gauge‐invariant atomic orbital (GIAO) approach has been studied at the PBE/3ζ level (as implemented in PRIRODA code) using linear regression analysis with experimental data. Empirical corrections for the calculated chemical shifts δH,calc = δPBE/3ζ − 0.08 ppm (RMS 0.18 ppm, MAD 0.66 ppm) and δC,calc = δPBE/3ζ − 6.35 ppm (RMS 3.09 ppm, MAD 9.42 ppm) have been developed using the sets of 263 and 308 experimental values for 1H and 13C chemical shifts, respectively. The confidence intervals of NMR chemical shifts at 95% confidence probability are δH,calc ± 0.35 ppm for 1H and δC,calc ± 6.05 ppm for 13C.

1H and 13C NMR chemical shift assignments of spiro-cycloalkylidenehomo- and methanofullerenes by the DFT-GIAO method.

The 1H and 13C NMR chemical shifts of spiro‐cycloalkylidene[60]fullerenes were assigned using experimental NMR data and the Density Functional Theory (DFT)–Gauge Independence Of Atomic Orbitals method (GAIO) calculation method in the Perdew Burke Ernzerhof (PBE)/3z approach. The calculated values of the 13C NMR chemical shifts adequately reproduce the experimental values at this quantum chemistry approach. Similar assignments will be helpful for 13C NMR spectral analysis of homo‐ and methano[60]fullerene derivatives for structure elucidation and to determine the influence of fullerene frames on substituents and the influence of substituents on fullerene cores. Copyright

Synthesis, structure and photochromic properties of hybrid molecules based on fullerene C60 and spiropyrans

The 1,3-dipolar cycloaddition of azomethine ylides to fullerene C60 was utilized to perform the synthesis of spiropyran-containing photochromic pyrrolidinofullerenes. It was found that photochromism is observed only for the hybrid compound containing an NO2 group in the pyran moiety, whereas the pyrrolidinofullerenes with Cl or F atoms in the spiropyran moiety do not possess photochromism. The photochromic fullerene hybrid is characterized by lower light sensitivity and photodegradation parameters compared to the initial spiropyrans, which can be attributed to reabsorption of activating radiation.

Synthesis and 13C NMR features of N-substituted aziridino[60]fullerenes

An effective cycloaddition of organic azides to fullerene C60 in the presence stoichiometric amounts of Cu(OTf)2 to form individual aziridino[60]fullerenes was developed. Considering the 13C NMR data, it was ascertained that among the synthesized aziridinofullerenes only the compound with the adamantane substituent possessed the local C2v symmetry of the fullerene core. In the 13C NMR spectra of the other compounds, 11 resonances were unexpectedly observed for the fullerene carbon atoms instead of probable 16 signals. The 13C NMR chemical shifts were computed with the high level GIAO-PBE/3ζ technique and the possible reasons of the signal overlap in the 13C NMR spectra were discussed.

Aminomethylation of Fullerene C60 with N,N′,N″-Triaryl- or N,N′,N″-Trihetaryl-1,3,5-perhydrotriazines in the Presence of EtMgBr and Ti(Oi-Pr)4

A new method for the functionalization of fullerenes based on the reaction between in situ generated aryl- or hetaryl-containing 1,3,5-perhydrotriazines and EtMgBr in the presence of Ti(Oi-Pr)4 has been developed. The cleavage of the triazine ring under previously developed conditions1-6 results in the formation of aminomethylated derivatives of fullerene C60 with high yields (80-90%) and selectivity (∼90%).