The synthesis, crystal structure and metal complexes of a new macrocyclic dinucleating ligand, 3,6,9,17,20,23-hexaaza-29,30-dihydroxy-13,27-dimethyl-tricyclo[23,3,1,1(11,15)] triaconta-1(28),11,13,15(30),25,26-hexaene

A new dinucleating 24-membered hexaazadiphenol macrocyclic ligand. 3,6,9,17 ,20,23-hexaaza-29,30-dihydroxy- 13,27-dimethyltricyclo[23,3,1,11(11.15)] tr iaconta-1(28),11,13,15(30),25,26-hexaene, BDBPH, was synthesized by the NaB H4 reduction of the Schiff base obtained from the [2 + 2] condensation betw een diethylenetriamine and diformyl-p-cresol. The hexahydro-bromide salt of BDBPH. BDBPH . 6HBr . 4H(2)O, crystallizes in the monoclinic system, space group P2(1)/c, with a = 14.441(5), b = 11.482(4), c = 12.090(6) Angstrom, alpha = 90, beta = 96.92, gamma = 90 degrees, V = 1990.0(14) Angstrom(3), a nd Z = 2. The protonation constants of BDBPH and the stability complexes wi th Cu(II), Zn(II), Mn(II), Cd(II), anJ Fe(III) in 1:1 and 2:1 systems (meta l:BDBPH) were determined by potentiometric measurement at 25.0 degrees C an d mu = 0.100 M KCl. Potentiometric equilibrium studies indicate that a vari ety of deprotonated, protonated mononuclear and dinuclear, as well as hydro xo-bridged complexes, form in the p[H] range 2-12 in aqueous solution. The species distributions and the characteristics of these complexes are also d escribed. (C) 2000 Elsevier Science S.A. All rights reserved.