DFT calculation of structures and NMR chemical shifts of simple models of small diameter zigzag single wall carbon nanotubes (SWCNTs)

Mechanochemical Preparation of Edge-Selectively justify Hydroxylated Graphene Nanosheets Using Persulfate via a Sulfate Radical-Mediated Process

The production of water-dispersed graphene with low defects remains a challenge. The dry ball milling of graphite with additives produces edge-selectively functionalized graphene. However, the "inert" additives require a long milling time and cause inevitable in-plane defects. Here, the mechanochemical reaction of graphite with persulfate solved the above drawback and produced edge-selectively hydroxylated graphene (EHG) nanosheets through a 2 h ball-milling and a subsequent 0.5 h sonication. The mechanochemical cleavage of persulfate yielded SO₄ ⋅^- to spontaneously oxidize graphite to form the carbon radical cations selectively at edges, followed by hydroxylation with water of moisture. Because the O-O bond dissociation energy of persulfate is 20 % of the graphitic C-C bond, the rather low milling energy allowed the hydroxylation of graphite at edges with nearly no in-plane defects. The obtained EHG showed high water-dispersibility and excellent photothermal and electrochemical properties, thereby opening up a new door to fabricate graphene-based composites.

Computational 1 H and 13 C NMR in structural and stereochemical studies

Present review outlines the advances and perspectives of computational ¹ H and ¹³ C NMR applied to the stereochemical studies of inorganic, organic, and bioorganic compounds, involving in particular natural products, carbohydrates, and carbonium ions. The first part of the review briefly outlines theoretical background of the modern computational methods applied to the calculation of chemical shifts and spin-spin coupling constants at the DFT and the non-empirical levels. The second part of the review deals with the achievements of the computational ¹ H and ¹³ C NMR in the stereochemical investigation of a variety of inorganic, organic, and bioorganic compounds, providing in an abridged form the material partly discussed by the author in a series of parent reviews. Major attention is focused herewith on the publications of the recent years, which were not reviewed elsewhere.

A DFT study on the adsorption of DNA nucleobases on the C3N nanotubes as a sequencer

Deoxyribonucleic acid (DNA) sequencing is a crucial issue for the cure of different kinds of diseases. Here, we computationally explored the effect of DNA nucleobases on the electronic properties and electrical conductivity of a zigzag (10,0) C₃N nanotube (C₃NNT) at B3LYP-gCP-D3 level of theory. Our calculations revealed that the binding energy of nucleobases shows the order of guanine (G) > cytosine (C) > thymine (T) > adenine (A). Based on the energy decomposition analysis (EDA), the G, C, and T strongly interact with the C₃NNT, but the A nucleobase adsorbed mainly via electrostatic attraction and dispersion forces. We exposed that the nucleobase size and its carbonyl group determine its adsorption behavior. The DNA nucleobase adsorption meaningfully increased the electrical conductivity of C₃NNT. The C₃NNT sensing response toward G, C, T, or A was predicted to be 131, 66, 60, or 10. Therefore, the C₃NNT might be applied to selectively detect the G, C, T, and A. Our findings expose the usefulness of C₃NNT as a next-generation DNA sequencer, suggesting new leads for future progresses in sustainable designs, superior sensing architectures, and bioelectronics.

Computational protocols for calculating 13C NMR chemical shifts

The most recent results dealing with the computation of ¹³C NMR chemical shifts in chemistry (small molecules, saturated, unsaturated and aromatic compounds, heterocycles, functional derivatives, coordination complexes, carbocations, and natural products) are reviewed, paying special attention to theoretical background and accuracy, the latter involving solvent effects, vibrational corrections, and relativistic effects.