Synthesis and Photoluminescence of Tetracyanidonitridorhenium(V) Complexes with Five-Membered N‑Heteroaromatic Ligands and Photoluminescence-Intensity Change
dataset
posted on 2019-12-17, 08:29 authored by Moe Seike, Kojiro Nagata, Hayato Ikeda, Akitaka Ito, Eri Sakuda, Noboru Kitamura, Atsushi Shinohara, Takashi YoshimuraNovel tetracyanidonitridorhenium(V)
complexes with five-membered
N-heteroaromatic ligands, (PPh4)2[ReN(CN)4L] [L = imidazole (Him) (2), 1-methylimidazole
(Mim) (3), and pyrazole (pyz) (4)] and (PPh4)2[ReN(CN)4L]·L [L = Him (5) and Mim (6)], were synthesized by the reactions
of (PPh4)2[ReN(CN)4] (1) with Him, Mim, and pyz, and their structures were determined by
single-crystal X-ray analysis. The complexes 2, 3, 4, and 6 showed intense photoluminescence,
with the emission quantum yields (Φem) being 0.65–0.75 in the solid state
at 296 K. In contrast, the Φem and τem values of 5 are significantly smaller and shorter,
respectively, than the relevant values of 2. The interconversion
reactions among 1, 2, and 5 accompanied by large photoluminescence-intensity changes were accomplished
by solvent-free reactions and exposure of water. The mechanochemical
reaction of 2 with 1 mol equiv of Him in the solid state
gave 5. Complex 5 was also obtained by the
mechanochemical reaction of 1 with 2 mol equivalents
of Him in the solid state. By placing solid of 5 in water,
the solid showed intense photoluminescence to give 2.
Complex 1 was produced under vacuum at 185 °C from 2 or 5.
