Abstract: Anew dinucleating 24-membered hexaazadiphenol macrocyclic 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 (BDBPH), was synthesized by the NaBH₄ reduction of the Schiff base obtained from the [2+2] condensation between diethylenetriamine and diformyl-p-cresol. The crystal structure of the hexahydrobromide salt of BDBPH, BDBPH·6HBr·4H₂O, was determined by single crystal X-ray diffractometry. It crystallized in the monoclinic system, space group P2_1/c , with a=1.4441(5) nm, b=1.1482(4) nm, c=1.2090(6) nm, α=90°, β=96.92°, γ=90°, V=1.9900(4) nm³ and Z=2. The macrocyclic ligand adapts a chair conformation, the crystallographic inversion center is located in the macrocyclic cavity, the six bromide ions and four water molecules are situated symmetrically outside the macrocyclic cavity. The new ligand with structural characteristics can be used for the study on the stabilities and catalytic properties of the corresponding metal complexes.

Key words: Macrocyclic ligand, Synthesis, Crystal structure