J. Harada et al., THE CENTRAL C-C BOND-LENGTH IN THE BI(ANTHRACENE-9,10-DIMETHYLENE) PHOTOISOMER - UNUSUAL ELONGATION AND CRYSTALLINE STATE REACTION, Molecular crystals and liquid crystals science and technology. Section A, Molecular crystals and liquid crystals, 276, 1996, pp. 119-123
Crystal structure analysis of bi(anthracene-9,10-dimethylene) photoiso
mer (1) revealed that the anomalous elongation of the central C-C bond
in the previously reported X-ray structure is an artifact caused by p
artial cycloreversion of 1 to no-bonded isomer in crystalline state.