Fig. 1

Overview of reported in situ photoreaction detection devices as well as the photoreactor in this study

Fig. 2

Synthesis of pyridine salt substrates and construction of thick cyclic compound 1. (a) Synthesis of pyridine salt substrate; (b) synthesis of thick cyclic compound 1

Fig. 3

Spectrogram and physical picture of the light source. (a) Spectrogram of light source exit; (b) spectrogram of optical fiber exit; (c) physical diagram of light source

Fig. 4

Schematic and physical diagram of the optical path system

Fig. 5

Schematic and physical diagram of coaxial collimated connector

Fig. 6

Schematic and physical diagram of solution homogenization system

Fig. 7

Thermal map of the dynamic nuclear polarization (DNP) phenomenon (c) of 6 photosensitizers (a) and 9 fluorinated aromatic compounds (b) under light conditions. * When the color is white, the magnification value fluctuates around 0.8~1.2, with no significant oversensitization. The closer the color value is to 5 (red), the greater the magnification of the signal strength and the more pronounced the supersensitization phenomenon.

Fig. 8

Effects of different concentrations of riboflavin on photochemically induced dynamic nuclear polarization of 4-fluorophenol in the dark and under light conditions. (a) Sensitization effect curves of different concentrations of riboflavin; (b) sensitization effect NMR spectra and NMR sample tubes under light conditions

Table 1

Signal-to-noise ratio (S/N) of NMR signals of different concentrations of riboflavin mixed with 4-fluorophenol in the dark and under light conditions

Fig. 9

Effects of different concentrations of eosin Y on the photochemically induced dynamic nuclear polarization of 4-fluorophenol in the dark and under light conditions. (a) Sensitization effect curves of different concentrations of eosin Y; (b) sensitization effect NMR spectra and NMR sample tubes under light conditions

Table 2

Signal-to-noise ratio values (S/N) of NMR signals of different concentrations of eosin Y mixed with 4-fluorophenol in the dark and under light conditions

Fig. 10

Effect of surface-treated NMR tubes on photochemically induced dynamic nuclear polarization. (a) histogram of the trend of the effect of paint spraying on sensitization; (b) picture of paint sprayed NMR tubes; (c) histogram of the trend of the effect of sandblasting on sensitization; (d) picture of sandblasted NMR tubes

Table 3

Effect of sensitization on NMR sample tubes with paint treatment (left) and sandblasting (right)

Fig. 11

Validation of synergistic work of in situ photoreactor and NMR spectrometer, and spectra of local signal changes before and after the reaction. (a) Reaction course 1H NMR iterogram of the photopromoted ring-opening reaction; (b) localized 1H NMR signal change stack plot; (c) localized signal change spectrum before and after the reaction