BI[1,3-BIS(DICYANOMETHYLENE)INDAN-2-YLIDENE] - AN ETHYLENE DERIVATIVE WITH EXTREMELY PRONOUNCED TWISTING OF THE C=C-BOND

Two rotational isomers of an ethylene derivative could for the first time be prepared and structurally characterized: the almost planar 1 and the twisted 2, which probably has the largest twist angle (approximately 50°) of all symmetrically substituted ethylenes yet synthesized. The longest wavelength absorption maximum of the twisted compound 2 undergoes a bathochromic shift of 105 nm relative to that of 1. (Figure Presented.) Copyright © 1993 by VCH Verlagsgesellschaft mbH, Germany