Luminescent Cu nanoclusters (NCs) are potential phosphors for illumination and display, but the difficulty in achieving full-color emission greatly limits practical applications. On the basis of our previous success in preparing Cu NC self-assembly architectures with blue-green and yellow emission, in this work, Cu NC self-assembly architectures with strong red emission are prepared by replacing alkylthiol ligands with aromatic thiols. The introduction of aromatic ligands is able to influence the ligand-to-metal charge transfer and/or ligand-to-metal-metal charge transfer, thus permitting the tuning of the emission color and enhancing of the emission intensity. The emission color can be tuned from yellow to dark red by choosing the aromatic ligands with different conjugation capabilities, and the photoluminescence quantum yield is up to 15.6%. Achieving full-color emission Cu NC self-assembly architectures allows the fabrication of Cu NC-based white light-emitting diodes.

First principles calculations show that the neutral U@C28 has a (cage)(2) ground state with Td symmetry instead of the long believed (5f)(1)(cage)(1) ground state with D2 symmetry. Its 34 valence electrons preferentially obey the 32-electron principle which fills all the s-, p-, d-, and f-type valence shells of the uranium atom. The remaining two valence electrons cannot break the electronic configuration and thus are located on the cage.

Recent experimental and theoretical researches have gradually proved that hydrogen bond (H-bond) interactions are not simple traditionally considered electrostatic interaction. Instead, they involve electron density delocalization. In this work, we outline the studies of electronic structures of the H-bond systems in water systems and biological organic molecules systems. Theoretical researches based on the first-principles method have found important evidences for electron density delocalization in H-bond region. Topological analysis based on natural bond orbital (NBO) analysis proves that during the formation of the H-bonds, electrons transfer from B orbitals to A-H antibond orbitals. Energy decomposition analyses revealed that the delocalized electronic structures show strong relations with orbital interactions. Moreover, penetrating molecular orbitals (MOs) are proved to contribute to the electron density delocalization of the H-bonds, and the quantitative contributions for such MOs could be obtained with the electronic density projected integral (EDPI) method. The electronic delocalization and the corresponding penetrating MOs could be visualized in water clusters, based on the firstprinciples method. These researches open a new sight for understanding the electronic structures of H-bonds from atomic level, and even contribute to further controlling proton tunneling as well as charge and energy transfer processes.

As an essential interaction in nature, hydrogen bonding plays a crucial role in many material formations and biological processes, requiring deeper understanding. Here, using density functional theory and post-Hartree-Fock methods, we reveal two hydrogen bonding molecular orbitals crossing the hydrogen-bond’s O and H atoms in the water dimer. Energy decomposition analysis also shows a non-negligible contribution of the induction term. Our finding sheds light on the essential understanding of hydrogen bonding in ice, liquid water, functional materials and biological systems.