ABSTRACT
The synthesis and characterisation of novel chelate nitrogen ligands with phasmidic tails (pyridine-triazole ligand 1b; 2,2'-bipyrimidine ligands 2b and 3b) as well as their titanium(IV) coordination complexes are reported. The analogous ligands 1a, 2a and 3a with methoxy substituents instead of the tails were also synthesized, together with titanium complexes that could be crystallographically characterised. A good agreement is noticed between analytical data of the complexes in solution (NMR) and in the solid state (X-ray diffraction). The complexes are overall robust on phases like alumina or silica, so that they could be characterised by TLC and sometimes chromatographied. Supramolecular architectures were generated from an equimolar solution of titanium(IV) isopropoxide, ligand 1a and a polyphenol ligand 5-H4, leading to a double-stranded helicate characterised by MS, NMR and crystallography, which was then converted into a trinuclear complex as shown by MS and NMR DOSY data. The liquid-crystalline behaviour of the ligands 1b, 2b and 3b incorporating the long alkyl tails and that of the complexes derived from these ligands have been investigated.
ABSTRACT
Stable complexes [Ti(1a)(2)2] and [Ti(1b)(2)2], where 2 is the 6,6'-diphenyl-2,2'-biphenolato ligand and 1a and 1b ligands are 2,2'-bipyrimidine derivatives, are synthesized. The complex [Ti(1b)(2)2] containing a diimine ligand substituted with long alkyl chains (C16) exhibits a liquid crystal behaviour. This property and self-assembling in the crystalline state are explained by the particular molecular conformation of the complexes.
