Synthesis And Diastereoselective Structural Change Of A Photochromic Transition Metal Complex, (Eta(6)-Spirobenzopyran)(Tricarbonyl)Chromium

Photochromic transition metal complexes, (eta(6)-spirobenzopyran)Cr(CO)(3), were synthesized and the structure was determined by an X-ray crystallographic and H-1 NMR measurements. The ring formation during its synthesis and ring closing reaction during and after UV irradiation proceeded diastereoselectively to let chromium atom and oxygen atom of the pyran ring locate on the same side of the indoline ring.