Routes to titanium tetrazole complexes

The titanium tetrazole coordination complex [TiCl₄ ·(PhCN₄H)₂] has been prepared by treatment of TiCl₄ with two equivalents of 5-phenyltetrazole in dichloromethane and spectroscopically and crystallographically characterised. The solid-state structure of this compound consists of six-coordinate titanium centres with cis ligated tetrazoles. The individual [TiCl₄·(PhCN ₄H)₂] dimerise via intermolecular N⋯H-N hydrogen bonding interactions and are further organised into 2D supramolecular arrays. Mass spectral evidence indicates that the individual tetrazole ligands are only weakly bound, limiting the potential of this complex as a titanium nitride precursor. 3+2 cycloaddition of tributyltin azide with 2-toluinitrile at 200°C has afforded the tributylstannyl tetrazole[SnBu₃{5-(2- MeC₆H₄)CN₄}]_n. Crystallographic analysis shows that this compound exists as a supramolecular coordination polymer propagated via trigonal bipyramidal tin centres linked by N ¹-Sn-N³ interactions. Preliminary reactivity studies of this tin complex with titanium tetrachloride in an effort to synthesise a covalently bound titanium tetrazolyl complex have thus far yielded incomplete elimination of the expected Bu₃SnCl by-product and intractable titanium-containing products.