A hexacarboxylic acid hexa-amide adapted for forming lipophilic complexes with magnesium ions, and lipophilic complexes of said hexacarboxylic acid hexa-amide with magnesium ions, said hexacarboxylic acid hexa-amide having the following formula VIII ##STR24## wherein (i) n, n' and n" are independently 1 or 2,
- (ii) R.sub.1, R.sub.1 ', R.sub.3 and R.sub.3 " are independently selected from the group A consisting of hydrogen, C.sub.1 -C.sub.15 alkyl, C.sub.2 -C.sub.15 alkenyl, C.sub.2 -C.sub.15 alkynyl, and cyclohexyl and phenyl;
- (iii) R.sub.2 and R.sub.4 are independently selected from the group B consisting of divalent, aliphatic, alicyclic and aromatic hydrocarbon radicals,
- (iv) R.sub.1 " and R.sub.2 " are independently selected from the group A as defined above;
- (v) R.sub.3 ' and R.sub.4 ' are independently selected from group A defined above;
- and
- (vi) R.sub.5, R.sub.5 ', R.sub.5 ", R.sub.6, R.sub.6 ' and R.sub.6 " are independently selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl and halogen.