Structural Studies of Some Binaphthyl Derivatives

Crystal structures of several 1,1'-binaphthyl derivatives have been determined. In particular compounds which at the 2,2' positions have either identical ethoxy groups or a closed bridged ether and furthermore have identical substitution at the 6,6' positions. The latter groups may be Br, CHO, CN or H. As would be expected, the torsional angle of the central 1-1' bond varies considerably in the open forms whereas the torsion is rather restricted in the closed forms. Unfortunately, good quality crystals for structural studies are difficult to grow and, therefore, rather high residuals are generally obtained. Some of the compounds have been tested for nonlinear optical activity (powder second harmonic generation, SHG).