THE CONNECTION BETWEEN 1JS']JSIH COUPLING-CONSTANTS AND GROUP ELECTRONEGATIVITIES IN SILANES

From n.m.r. coupling constants in silanes of the type HSiMe3-n(X)n (X = CH2SiMe3, NHSiMe3, N(SiMe3)2, OSiMePhCH2CH3, OSiMePhCH2Cl; n=0...3) substituent parameters a for the groups X were deduced showing distinct dependencies not only on the atoms directly bonded to the silicon atom but also on the atoms which are separated by two or more bonds from the silicon atom. These parameters supplement an excisting body of substituent parameters. They can be used to predict coupling constants. The good correlation of the parameters-alpha with the electronegativities-chi has been used to estimate group electronegativities of the above mentioned groups and, additionally, of the group OSiH3.