... 7 . J.7 chemistry 1979, 18, 504f8-5050. 133-170. ... Chemical shifts are expressed in 6 units with Me4Si as an internal standard. J values are in hertz. UV and visible spectra were measured on a Cary 15 spectropho- tometer. ... Obshch. Khim. 1960,30,1336-1339; Chem. Abstr. ...