Crystal structure of 2-(4-tert-butyl-phen-yl)-3-hydroxy-4H-chromen-4-one

Synthesis, crystal structure, photoluminescence and photochemistry of bis(triphenylphosphine)silver(I) flavonolate

The complex Ag(I)(flavonolate)(PPh3)2 has been prepared and characterized including the crystal structure. This compound shows in degassed solution two emission bands, a fluorescence at λ max=505 nm and a phosphorescence at λ max=780 nm. Both emissions originate from lowest-energy flavonolate intraligand excited singlet and triplet states, respectively. In the presence of oxygen, the phosphorescence disappears and the complex becomes light-sensitive. The flavonolate ligand undergoes a photooxidation by oxygen.

2-(2-Fluorophenyl)-3-hydroxy-4H-chromen-4-one

The asymmetric unit of the title compound, C15H9FO3, contains two independent molecules in which the fluorine-substituted benzene ring is twisted by 47.64 (3) and 56.02 (4)° relative to the 4H-chromenon skeleton. The hydroxyl group in each molecule is tilted from 4H-chromenon skeleton by 24.5 (1) and 16.1 (1)°, respectively. In the crystal, pairs of O—H...O hydrogen bonds form inversion dimers with an R 2 2(10) graph-set motif.

Crystal structure of 2-(2,3-di-meth-oxy-naphthalen-1-yl)-3-hy-droxy-6-meth-oxy-4H-chromen-4-one

In the title compound, C22H18O6, the dimeth-oxy-substituted naphthalene ring system is twisted relative to the 4H-chromenon skeleton by 88.96 (3)°. The two meth-oxy substituents are tilted from the naphthalene ring system by 1.4 (4) and 113.0 (2)°, respectively. An intra-molecular O-H⋯O hydrogen bond closes an S(5) ring motif. In the crystal, pairs of O-H⋯O hydrogen bonds form inversion dimers with R (2) 2(10) loops and C-H⋯O inter-actions connect the dimers into [010] chains.