Abstract: A process is described for the preparation of a manganese complex catalyst having the formula: ##STR1## wherein Mn is manganese in the +4 oxidation state; R is a C.sub.1 -C.sub.20 radical selected from the group consisting of alkyl, cycloalkyl, aryl, benzyl and radical combinations thereof;at least two R radicals may also be connected to one another so as to form a bridging unit between two oxygens that coordinate with the manganese;L is a ligand selected from a C.sub.3 -C.sub.60 radical having at least 3 nitrogen atoms coordinating with the manganese; andY is an oxidatively-stable counterion;the process includes the steps of:(i) reacting in an nonaqueous alcoholic medium a manganese (II) salt with the ligand L to form a manganese coordinated substance, a counterion salt M.sub.z Y.sub.