Synthesis and molecular structures of phenylamides of magnesium, calcium, strontium, and barium--from molecular to polymeric structures

Several preparative procedures for the synthesis of the THF complexes of the alkaline earth metal bis(phenylamides) of Mg (1), Ca (2), Sr (3), and Ba (4) are presented such as metalation of aniline with strontium and barium, metathesis reactions of MI2 with KN(H)Ph, and metalation of aniline with arylcalcium compounds or dialkylmagnesium. The THF content of these compounds is rather low and an increasing aggregation is observed with the size of the metal atom. Thus, tetrameric (THF)2Ca{mu-N(H)Ph}2]4 (2) and polymeric (THF)2Sr{mu-N(H)Ph}2]infinity and {(THF)2Ba{mu-N(H)Ph}2]2(THF)Ba{mu-N(H)Ph}2]2}infinity show six-coordinate metal atoms with increasing interactions to the pi systems of the phenyl groups with increasing the radius of the alkaline earth metal atom.