Effective Photosensitization in Excited-State Equilibrium: Brilliant Luminescence of Tb Coordination Polymers Through Ancillary Ligand Modifications.

Invited for this month's cover are the collaborating groups of Yuichi Kitagawa, Yasuchika Hasegawa, Tetsuya Taketsugu, and co-workers at Hokkaido University. The cover picture shows a photosensitizer that has a long excited-state lifetime and provides strong emissions for Tb coordination polymers. The photosensitization ability can be considerably altered by changing the ancillary ligands in the Tb coordination polymers.

Effective Photosensitization in Excited-State Equilibrium: Brilliant Luminescence of Tb Coordination Polymers Through Ancillary Ligand Modifications.

Molecular photosensitizers provide efficient light-absorbing abilities for photo-functional materials. Herein, effective photosensitization in excited-state equilibrium is demonstrated using five Tb coordination polymers. The coordination polymers are composed of Tb ions (emission center), hexafluoroacetylacetonato (photosensitizer ligands), and phosphine oxide-based bridges (ancillary ligands).

Coordination Geometrical Effect on Ligand-to-Metal Charge Transfer-Dependent Energy Transfer Processes of Luminescent Eu(III) Complexes.

Photophysical properties of europium (Eu(III)) complexes are affected by ligand-to-metal charge transfer (LMCT) states. Two luminescent Eu(III) complexes with three tetramethylheptadionates (tmh) and pyridine (py), [Eu(tmh)(py)] (seven-coordinated monocapped-octahedral structure) and [Eu(tmh)(py)] (eight-coordinated square antiprismatic structure), were synthesized for geometrical-induced LMCT level control. Distances between Eu(III) and oxygen atoms of tmh ligands were estimated using single-crystal X-ray analyses.

All-electron relativistic spin-orbit multireference computation to elucidate the ground state of CeH.

The all-electron relativistic spin-orbit multiconfiguration/multireference computations with the Sapporo basis sets were carried out to elucidate the characters of the low-lying quasi-degenerate electronic states for the CeH diatomic molecule. The present computations predict the ground state of CeH to be a pure quartet state of 4f15d1(5dσ-H1s)26s1 configuration (Ω = 3.5).

All-electron relativistic computations on the low-lying electronic states, bond length, and vibrational frequency of CeF diatomic molecule with spin-orbit coupling effects.

Ab initio all-electron computations have been carried out for Ce and CeF, including the electron correlation, scalar relativistic, and spin-orbit coupling effects in a quantitative manner. First, the n-electron valence state second-order multireference perturbation theory (NEVPT2) and spin-orbit configuration interaction (SOCI) based on the state-averaged restricted active space multiconfigurational self-consistent field (SA-RASSCF) and state-averaged complete active space multiconfigurational self-consistent field (SA-CASSCF) wavefunctions have been applied to evaluations of the low-lying energy levels of Ce with [Xe]4f 5d 6s and [Xe]4f 5d configurations, to test the accuracy of several all-electron relativistic basis sets. It is shown that the mixing of quartet and doublet states is essential to reproduce the excitation energies.

Development of efficient time-evolution method based on three-term recurrence relation.

The advantage of the real-time (RT) propagation method is a direct solution of the time-dependent Schrödinger equation which describes frequency properties as well as all dynamics of a molecular system composed of electrons and nuclei in quantum physics and chemistry. Its applications have been limited by computational feasibility, as the evaluation of the time-evolution operator is computationally demanding. In this article, a new efficient time-evolution method based on the three-term recurrence relation (3TRR) was proposed to reduce the time-consuming numerical procedure.

Reconsidering an analytical gradient expression within a divide-and-conquer self-consistent field approach: exact formula and its approximate treatment.

An analytical energy gradient formula for the density-matrix-based linear-scaling divide-and-conquer (DC) self-consistent field (SCF) method was proposed in a previous paper by Yang and Lee (YL) [J. Chem. Phys.

Short-time Fourier transform analysis of real-time time-dependent Hartree-Fock and time-dependent density functional theory calculations with Gaussian basis functions.

We propose a novel analysis of real-time (RT) time-dependent Hartree-Fock and time-dependent density functional theory (TDHF/TDDFT) calculations using a short-time Fourier transform (STFT) technique. RT-TDHF/TDDFT calculations of model dimers were carried out and analyzed using the STFT technique, in addition to the usual Fourier transform (FT). STFT analysis revealed that the induced polarization propagated between the molecules through the intermolecular interaction; that is, it directly showed the electron dynamics of the excited system.

Implementation of divide-and-conquer method including Hartree-Fock exchange interaction.

The divide-and-conquer (DC) method, which is one of the linear-scaling methods avoiding explicit diagonalization of the Fock matrix, has been applied mainly to pure density functional theory (DFT) or semiempirical molecular orbital calculations so far. The present study applies the DC method to such calculations including the Hartree-Fock (HF) exchange terms as the HF and hybrid HF/DFT. Reliability of the DC-HF and DC-hybrid HF/DFT is found to be strongly dependent on the cut-off radius, which defines the localization region in the DC formalism.

Second-order Møller-Plesset perturbation energy obtained from divide-and-conquer Hartree-Fock density matrix.

The density matrix (DM) obtained from Yang's [Phys. Rev. Lett.

Biological evaluation of sphingomyelin analogues as inhibitors of sphingomyelinase.

Seeking neutral sphingomyelinase inhibitors, we designed and synthesized hydrolytically stable analogues of sphingomyelin. These novel analogues replace the phosphodiester moiety of sphingomyelin with carbamate and urea moiety, resulting in inhibition of neutral sphingomyelinase. Compound 1 prevented ceramide generation and apoptotic neuronal cell death in a model of ischemia based on organotypic hippocampal slice cultures.

Sphingomyelin analogues as inhibitors of sphingomyelinase.

To search for neutral sphingomyelinase inhibitors we designed and synthesized hydrolytically stable analogues of sphingomyelin. The novel compounds 8 and 9 which were replaced the phosphodiester moiety of sphingomyelin with the carbamate moiety showed inhibitory activity with an IC(50) value of micro M on neutral sphingomyelinase in rat brain microsomes. Compound 8i showed a selective neutral sphingomyelinase inhibitory activity.

Increase in secretion of glial cell line-derived neurotrophic factor from glial cell lines by inhibitors of vacuolar ATPase.

Glial cell line-derived neurotrophic factor (GDNF) was reported to be effective for treating subjects with neurodegenerative diseases such as Parkinson's disease. In search of finding a compound which promotes GDNF secretion, we found that concanamycin A (ConA), a vacuolar ATPase (V-type ATPase) inhibitor purified from Streptomyces diastatochromogens, enhanced GDNF secretion from glioma cells. The rat glioma cell line, C6, and the human glioma cell lines, U87MG and T98G, abundantly expressed GDNF mRNA, and secreted GDNF into culture media, and this event was potently enhanced by a Ca(2+) ionophore and by phorbol ester, as noted in other cells.