Stability, electronic, and optical properties of two-dimensional phosphoborane.

The structure and properties of two-dimensional phosphoborane sheets were computationally investigated using Density Functional Theory calculations. The calculated phonon spectrum and band structure point to dynamic stability and allowed characterization of the predicted two-dimensional material as a direct-gap semiconductor with a band gap of ~1.5 eV.

Neutral Pyrrole Nitrogen Atom as a π- and Mixed n,π-Donor in Hydrogen Bonding.

9-Dimethylaminobenzo[ g]indoles 3-6 and 1-dimethylamino-8-(pyrrolyl-1)naphthalene 7 were examined as possible models for establishing the ability of the pyrrole nitrogen atom to participate in [NHN] hydrogen bonding as a proton acceptor. Indoles 3-5 (to a lesser extent 6) form rather stable tetrafluoroborates, with the proton mostly located on the NMe group but simultaneously engaged in the formation of a charged intramolecular [NHN] hydrogen bond (IHB) with the pyrrole N atom. The theoretically estimated energies of IHB in salts 3HBF-6HBF vary between 7.