Chelate complexes and processes for their preparation

A compound of formula I ##STR6## wherein M is an element of main group III or IV or the Periodic Table having an atomic number of from 31 to 50 inclusive, aluminum or ruthenium,

• R.sub.1 is a radical of formula II ##STR7## wherein m is 0 or 1,
• n is an integer from 0 to 200 inclusive,
• R.sub.5 and R.sub.6 are each independently of the other lower alkyl or unsubstituted or substituted phenyl, and
• R.sub.7 is alkylthio having 1 to 20 carbon atoms, alkanoyloxy having 1 to 20 carbon atoms, unsubstituted aliphatic hydrocarbyloxy having 1 to 24 carbon atoms, or, when m is 1 and n is 0, aliphatic hydrocaryl having from 12 to 24 carbon atoms, or
• R.sub.1 is a radical of formula III ##STR8## wherein X is a bivalent aliphatic hydrocarbon radical having 1 to 23 carbon atoms,
• Y is oxygen or the group --NH--,
• R.sub.8 is aliphatic hydrocarbyl having 1 to 24 carbon atoms or unsubstituted aliphatic hydrocarbyl having 1 to 24 carbon atoms in the aliphatic moiety, and
• R.sub.5, R.sub.6 and m are as defined above,
• R.sub.2 has the same definition as R.sub.1 when M is an element of main group IV, or R.sub.2 is absent when M is an element of main group III or ruthenium,
• R.sub.3 is hydrogen, lower alkyl, lower alkylthio, unsubstituted or lower alkoxy-substituted alkoxy having 1 to 20 carbon atoms, tri-lower alkylsilyl or halogen, and
• R.sub.4 is hydrogen, lower alkyl, lower alkylthio, unsubstituted or lower alkoxy-substituted alkoxy having 1 to 20 carbon atoms, tri-lower alkylsilyl or halogen.