THE INTERACTION OF TRANSITION AND POSTTRANSITION METAL-IONS WITH 14-MEMBERED AND 16-MEMBERED TRANS N(2)X(2)-DONAR MACROCYCLES (X=NH,O,S) - STABILITIES AND X-RAY STRUCTURES

A comparative investigation of the 1:1 (metal/ligand) complex stabilit ies of 14- and 16-membered derivatives of dibenzo-substituted macrocyc les incorporating trans-N2O2, -N2S2 and -N-4 donor sets towards Co(II) , Ni(II), Cu(II), Zn(II), Cd(LI), Ag(I) and Pb(II) ions has been carri ed out with emphasis on the influence of systematic donor atom variati on on the respective 1:1 stability constants. For comparison, previous ly determined log K values for corresponding cis-N2O2 and -N-4 donor l igand systems are also discussed. The crystal structures of the nickel (II) thiocyanate complexes of the 14-membered N-4(diamine) and precurs or N-4(diimine) macrocycles are also presented. C20H24N6NiS2 crystalli sed in the triclinic space group P (1) over bar (No. 2) with a = 8.913 (2) Angstrom, b = 9.441(2) Angstrom, c = 13.583(3) Angstrom, a = 94.29 (2)degrees, beta = 107.48(2)degrees, gamma = 90.90(2)degrees and Z = 2 . C20H20N6NiS2 . CH3CN crystallised in the monoclinic space group P2(1 )/n (No. 14) with a = 10.321(2) Angstrom, b = 13.855(8) Angstrom, c = 17.435(1) Angstrom, beta = 102.59(10)degrees and Z = 4.