in N,N-dimethyl-formamide under Ar, a mixture of the organic ligand, Ni-salt and dimethylformamiderefluxed for 1.5 h and evaporated to dryness by rotary evaporation (45. degree.C); solid chromatographed twice (basic Al2O3 III, ethyl acetate-toluene, 1:2), further chromatographed (Bio-Beads S-X1, toluene), dissolved in CH2Cl2, recovered with CH3OH, washed with CH3OH, vacuum-dried (room temp.);