N
‐Methyl‐4,4′‐bipyridinium and
N
‐Methyl‐
N′
‐oxide‐4,4′‐bipyridinium Bismuth Complexes – Photochromism and Photoluminescence in the Solid State
摘要:
AbstractThree bismuth complexes based on N‐methyl‐4,4′‐bipyridinium (hMV+), (hMV)[Bi(hMV)Cl5] (1), and N‐methyl‐N′‐oxide‐4,4′‐bipyridinium (MVO+), [Bi(MVO)X4(dmso)]·dmso [X = Cl (2), Br (3)], are reported. All three compounds show luminescence in the solid state with maxima at 545 nm (yellow for 1) and 560 nm (orange for 2 and 3) with quantum yields up to 10 %. Upon UV irradiation, 1 undergoes a color change from white to blue accompanied by a reduction of the photoluminescence intensity. The analysis of the crystal structure of the three complexes points to a photoinduced charge‐transfer (PICT) process at the origin of the photochromism in 1.