Disclosed is a catalyst having the general formula ##STR1## where Q is a ligand containing the ring ##STR2## R is hydrogen, N(R').sub.2, OR', or R', each R' is independently selected from alkyl from C.sub.1 to C.sub.10, aryl from C.sub.6 to C.sub.15, alkaryl C.sub.7 to C.sub.15, and aralkyl from C.sub.7 to C.sub.15, each X is independently selected from hydrogen, halogen, alkoxy from C.sub.1 to C.sub.10, dialkylamino from C.sub.1 to C.sub.10, methyl, ##STR3## each R.sub.1 is independently selected from halogen, alkoxy from C.sub.1 to C.sub.10, and R', L is ##STR4## Q, or X, where one .pi.-ligand can be bridged to second .pi.-ligand, B is an optional base, "n" is 0 to 5, and M is a Group 3-10 metal.

Se divulga un catalizador que tiene el ## general del ## STR1 del fórmula donde está un ligand Q que contiene el ## R del ## STR2 del anillo es hidrógeno, N(R').sub.2, O ', o R ', cada R ' se selecciona independientemente del alkyl de C.sub.1 a C.sub.10, del aryl de C.sub.6 a C.sub.15, del alkaryl C.sub.7 a C.sub.15, y del aralkyl de C.sub.7 a C.sub.15, cada X se selecciona independientemente del hidrógeno, halógeno, alkoxy de C.sub.1 a C.sub.10, dialkylamino de C.sub.1 a C.sub.10, metilo, el ## del ## STR3 cada R.sub.1 se selecciona independientemente del halógeno, alkoxy de C.sub.1 a C.sub.10, y R ', L es el ## Q del ## STR4, o X, donde un pi.-ligand se puede tender un puente sobre al segundo pi.-ligand, B es una base opcional, "n" es 0 a 5, y M es un metal del grupo 3-10.