Nickel containing organo-metallic compound as catalyst

The nickel-containing compound of the formula:

• ##STR36## wherein:
• R.sup.1 is C.sub.2-10 hydrocarbyl;
• each R.sup.4 is independently H or C.sub.1-20 hydrocarbyl;
• X.sup.1 is O or S;
• E.sup.1 is P, As or Sb;
• each of R5 and R6, independently is H, C.sub.1-20 hydrocarbyl or a functional group selected from --OR.sup.2, --Cl, --CO.sub.2 R.sup.2, --CO.sub.2 M, --C(O)N(R.sup.1).sub.2, --C(O)R.sup.2, --SR.sup.2, --SO.sub.2 R.sup.2, --OSO.sub.2 R.sup.2, --SOR.sup.2, --P(O)(OR.sup.2).sub.2-y (R.sup.1).sub.y, --CN, --NHR.sup.2, --N(R.sup.2).sub.2, ##STR37## --Si(OR.sup.1).sub.3-x (R.sup.1).sub.x, --OSi(OR.sup.1).sub.3-x (R.sup.1).sub.x, --NO.sub.2, --SO.sub.3 M, --PO.sub.3 M.sub.2 and --P(O)(OR.sup.2).sub.2 M wherein M is alkali or alkaline earth metal, ammonium, quaternary ammonium, phosphonium or arsonium, y is 0, 1 or 2, each R.sup.1, independently, is H or C.sub.1-20 hydrocarbyl, each R.sup.2, independently, is C.sub.1-20 hydrocarbyl and x is 0 or an integer of 1 to 3
• or R.sup.5 and R.sup.6, taken together, is a substituted or unsubstituted C.sub.5-8 alicyclic, C.sub.5-8 heterocyclic or C.sub.6-14 aromatic ring, the heteroatom of the heterocyclic ring being selected from O, N and S;
• and
• each R.sup.7, independently, is H, OSi(R'").sub.3, C.sub.1-20 alkyl or oxyalkyl, C.sub.6-20 aryl, alkaryl, aralkyl or oxyaryl, N(R.sup.2).sub.2 wherein each R.sup.2 independently is C.sub.1-20 hydrocarbyl or halogen, or both R.sup.7 groups, taken together, is a 5 to 8-membered heterocyclic ring wherein the heteroatom is selected from O, N and S;
• and
• each R'", independently, is C.sub.1-20 alkyl or oxyalkyl, C.sub.6-20 aryl, alkaryl, aralkyl or oxyaryl.