3,3′-{(1E,2E)-hydrazine-1,2-diylidenedi[(E)methylylidene]}dibenzene-1,2-diol (BCAz-H4):: an easy to prepare but very useful building block for the self-assembly of triple-stranded helicates;: the X-ray crystal structure of Na4[(BCAz)3Ti2]•7 dmf•H2O

The azine bridged dicatechol ligand BCAz-H-4 forms triple-stranded dinuclear helicates with titanium(IV) ions in the presence of alkali metal carbonate. The X-ray structure of Na-4[(BCAz)(3)Ti-2].7 dmf.H2O shows that countercations can be encapsulated in the interior of the helicate binding not only to internal oxygen atoms of the catecholates but also to nitrogen atoms of the spacer. (C) 2002 Elsevier Science Ltd. All rights reserved.