Plant growth acceleration using a transparent Eu3+-painted UV-to-red conversion film.

The stimulation of photosynthesis is a strategy for achieving sustainable plant production. Red light is useful for plant growth because it is absorbed by chlorophyll pigments, which initiate natural photosynthetic processes. Ultraviolet (UV)-to-red wavelength-converting materials are promising candidates for eco-friendly plant cultures that do not require electric power. In this study, transparent films equipped with a UV-to-red wavelength-converting luminophore, the Eu3+ complex, were prepared on commercially available plastic films for plant growth experiments. The present Eu3+-based films absorb UV light and exhibit strong red luminescence under sunlight. Eu3+-painted films provide significant growth acceleration with size increment and biomass production for vegetal crops and trees in a northern region. The plants cultured with Eu3+-painted films had a 1.2-fold height and 1.4-fold total body biomass than those cultures without the Eu3+ luminophores. The present film can promote the plant production in fields of agriculture and forestry.

Effective Photosensitization in Excited-State Equilibrium: Brilliant Luminescence of TbIII 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 TbIII coordination polymers. The photosensitization ability can be considerably altered by changing the ancillary ligands in the TbIII coordination polymers. The results provide new insights on the design of photosensitizers for improving the properties of photo-functional materials. More information can be found in the Research Article by Y. Kitagawa, Y. Hasegawa, and co-workers.

Effective Photosensitization in Excited-State Equilibrium: Brilliant Luminescence of TbIII 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 TbIII coordination polymers. The coordination polymers are composed of TbIII ions (emission center), hexafluoroacetylacetonato (photosensitizer ligands), and phosphine oxide-based bridges (ancillary ligands). The two types of ligand combinations induces a rigid coordination structure via intermolecular interactions, resulting in high thermal stability (with decomposition temperatures above 300 °C). Excited-triplet-state lifetimes of photosensitizer ligands (τ=120-1320 µs) are strongly dependent on the structure of the ancillary ligands. The photosensitizer with a long excited-triplet-state lifetime (τ≥1120 µs) controls the excited state equilibrium between the photosensitizer and TbIII , allowing the construction of TbIII coordination polymer with high TbIII emission quantum yield (≥70 %).

Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework.

Invited for the cover of this issue are Yuichi Kitagawa, Yasuchika Hasegawa, and co-workers at Hokkaido University. The image depicts tribo-excited chemical reaction using trivalent lanthanide complexes with stacked anthracene ligands. Read the full text of the article at 10.1002/chem.202104401.

Tribo-Excited Chemical Reaction Using an EuIII Complex with a Stacked Anthracene Framework.

A spin-selective tribo-chemical reaction using a dinuclear lanthanide complex is demonstrated for the first time. The dinuclear complex is composed of two EuIII ions, hexafluoroacetylacetonato ligands, and anthracene-based phosphine oxide bridges. Single-crystal analysis revealed a face-to-face-type anthracene dimer structure in the dinuclear EuIII complex. Mechanical stimulus on the dinuclear EuIII complex induced selective formation of oxidized anthracene. The tribo-chemical reaction is based on a characteristic energy-transfer pathway for the selective formation of an excited triplet state.