Kinetics and mechanism of formation of nickel(II) complexes of nitrogen–oxygen donor macrocyclic ligands in methanol, and the X-ray structure determination of one of the products, dichloro(6,7,8,9,10,11,17,18-octahydro-5H-dibenzo[e,n][1,4]dioxa[8,12]diazacyclopentadecine)-nickel(II)

Abstract

The kinetics of complexation of NiCl₂ in methanol with two O₂N₂-donor macrocyclic ligands have been studied by the stopped-flow technique. Complex formation involves a fast initial process controlled by the rate of methanol exchange for Ni^II, followed by a slower step which is postulated to involve a rearrangement of the ligand within the co-ordination sphere of the nickel (II) ion to form the final octahedral trans-dichloro-complex. An X-ray structure determination of the title complex [space group P2₁/c, a= 14.442(4), b= 10.867(3), c= 18.617(5)Å, β= 137.84(3)°(by heavy-atom method with 934 four-circle diffractometer data. R 0.063)] confirms a distorted trans-octahedral co-ordination geometry for the Ni^II.