We report TPE-incorporated squaraines with dual-state emission and decode their LE/TICT mechanism in solution and ESIPT mechanism in the crystalline state.

The photoreduction of carbon dioxide (CO2) to valuable fuels is a promising strategy for the prevention of rising atmospheric levels of CO2 and the depletion of fossil fuel reserves. However, most reported photocatalysts are only active in the ultraviolet region, which necessitates co-catalysts and sacrificial agents in the reaction systems, leading to an unsatisfied economy of the process in energy and atoms. In this research, a CuMoxW(1-x)O4 solid solution was synthesized, characterized, and tested for the photocatalytic reduction of CO2 in the presence of amines. The results revealed that the yield of CH3OH from CO2 was 1017.7 μmol/g under 24 h visible light irradiation using CuW0.7Mo0.3O4 (x = 0.7) as the catalyst. This was associated with the maximum conversion (82.1%) of benzylamine to N-benzylidene benzylamine with high selectivity (>99%). These results give new insight into the photocatalytic reduction of CO2 for valuable chemical products in an economic way.

A novel bifunctional photochromic compound 2 based on spirooxazine and cinnamoyl moiety was synthesized by esterification reaction. Its structure was characterized by 1 H NMR, 13 C NMR, IR and X-ray single crystal diffraction. The compound was proved by UV testing to have excellent photochromic properties both in organic solvents and polymer films when irridiated with high pressure Hg lamp. The acidichromism phenomenon of compound 2 was studied too. No significant fluorescence emission of compound 2 was observed in EtOH solution before and after irradiation. Under the acidic condition or irradiation with 150 W Xe lamp, The ethanol solution of compound 2 exhibits a good fluorescence respectively. The ethanol solution of compound 2 exhibits obvious fluorescence emission. After irradiating the acidic solution, new fluorescence emission can be observed. The emission change modulated by acid or light offers compound 2 to be potential as a new fluorescent molecular switch.

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