The electronic and magnetic properties of 3d VIIB and VIII atom-substituted C20 cage

To analyze the contributions of the metal atoms to stabilize and synthesize the small cage-like carbon clusters, the configurations, electronic and magnetic characteristics of Mn-, Fe-, Co- and Ni-substituted C[Formula: see text] cage have been investigated using the PBE functional. The results demonstrate that the TM (TM[Formula: see text]=[Formula: see text]Mn, Fe, Co and Ni) substitution decreases the structural stability of the C[Formula: see text] cages, while increases the activity of the C[Formula: see text] cages. Electronic migrations between the TM atoms and C atoms are less. All the TM–C bonds of the TMC[Formula: see text] and TM2C[Formula: see text] clusters display covalent bond characters. The [Formula: see text] orbitals of TM atoms lose electrons, the [Formula: see text] and [Formula: see text] orbitals of TM atoms obtain electrons. The special distributions of the HOMO states of the TMC[Formula: see text] and TM2C[Formula: see text] clusters are mainly from the hybridization of the C [Formula: see text] orbitals and the TM [Formula: see text] orbitals. The Mn2C[Formula: see text] cages display the highest spin polarization.

Evolution of the interaction between C20 cage and Cr(CO)5: A solvent effect, QTAIM and EDA investigation

This study used mpw1pw91 quantum chemical calculations in gas and solution phases to clarify the interaction between C20 and Cr(CO)5 fragment. It also sought to clarify the effects of solvent polarity on dipole moment, structural parameters, and frontier orbital energies of the complex. Energy decomposition analysis (EDA) was applied to analyze the bonding interaction between the C20 and Cr(CO)5 fragment. Percentage composition in terms of the defined groups of frontier orbitals for the complex was evaluated to characterize the metal–ligand bonds. The Cr–C bonds within the complex were examined using quantum theory of atoms in molecules (QTAIM) analysis. In order to determine the back-bonding effects in these bonds, QTAIM analysis was applied to calculate of the quadrupole polarization of the carbon atom.