MacLeod Carey, Desmond

The hydrogen storage properties of Ti-doped Bn ((Formula presented.)) clusters are investigated by using the “diatomic deposition method” with further evaluation by density functional theory computations. The results show that TiBn ((Formula presented.)) clusters possess the ability to storage up to four H2 molecules, reaching a mass fraction of 6.12%. Further, the hydrogen release temperature is analyzed by molecular dynamics simulations with a variable temperature. It turns out that the TiB7 and TiB9 clusters release the H2 molecules at T ≲ 700 K, while TiB8 requires higher temperature due to stronger interactions with the H2 molecules, confirmed by the electronic density of states. The size-dependent properties and odd–even nuclearity on the clusters can be useful for applications with controlled temperature. These results serve for further design of novel materials with reversible and controlled hydrogen storage properties based on TiB7/TiB9 motifs. Additionally, new lower-energy isomers for TiB4 and TiB9 clusters were found within the accuracy of the all-electron triple-ζ Slater [slater type orbital (STO)-Triple-zeta basis set(TZP)] basis set.

Recently, P. V. Nhatet al., have discussed and commented on our article (DOI: 10.1039/D0CP04018E) for the case of the most stable structure of Ag15. They have found a new most stable structure (labeled as 15-1) in comparison to the putative global minimum reported by us, which is a four layered 1-4-6-4 stacking structure with aC2vpoint group (15-2). In this reply, we have performed a larger structure search which allowed us to confirm the results of Nhatet al.The results show the existence of multiple isoenergetic isomers with similar structure motifs for the Ag15system, increasing the problem complexity to locate the global minimum. The results in regard to the structure and electronic properties of the new lowest energy structure are discussed.

The formation of supramolecular aggregates incorporating C60 fullerenes can be followed and characterized by nuclear magnetic resonance (NMR) measurements. Here, we unravel the particular patterns provided by zinc-porphyrin (ZnP)-bridged dimers, where the aromatic character of each ZnP unit leads to an enhanced shielding region for the closest fullerene atoms, denoting a slight shielding effect for the equatorial atoms. The nature of the stabilization is discussed and compared to a single ZnP-C60 aggregate and a ZnP-dimer (ZnP2-C60) model, with a significant contribution from noncovalent π-π interactions, allowing us to address the role of bridging chains. The experimental 13C-NMR spectrum of C60 in a bridged ZnP dimer shows a single peak owing to the constant tumbling inside the host, which averages the different groups of carbon atoms. The calculations in a static scenario reveal information concerning the local chemical environment underlying the observed shift in relation to isolated C60. We expect that the current approach can be useful to rationalize and predict the origin of the NMR shift upon the formation of host-guest aggregates involving small and large host species.