Two phthalocyanine units ‘stapled’ by carbon–carbon σ bonds in a new sandwich-type molecule: {5,5′;19,19′-bi[phthalocyaninato (2–)]}titanium(IV). Synthesis, X-ray crystal structure, and properties

Abstract

{5,5′;19,19′-Bi[phthalocyaninato(2–)]}titanium(IV)–1-chloronaphthalene(1/1 ), [TiL]·C₁₀H₇Cl, is obtained by the reaction of [Ti(pc)Cl₂](pc = phthalocyaninato dianion, [C₃₂H₁₆N₈]^2–) with Na₂(pc) in 1-chloronaphthalene at 190 °C, An X-ray single-crystal structure (monoclinic, space group C/2c, a= 16.327(3), b= 18.568(4), c= 19.022(4)Å; β= 94.50(1)°, Z= 4) indicates for this complex a sandwich-type structure with the titanium atom in the centre of the molecule and the two phthalocyaninato units ‘stapled’ by two inter-ring C–C σ bonds [C(11)–C(11′) 1.556(6) and C(31)–C(31′) 1.575(6)Å]. Due to the staggered orientations of the two macrocyclic rings (relative rotation 45°) the planes of the two inner N₄ systems (each of which is slightly distorted from planarity) form a square-antiprism, with an average interplane distance of 2.32 Å(much shorter than that found in similar ‘unstapled’ complexes), and Ti–N bond distances in the range 2.17–2.26 Å. The complex shows high thermal stability and can be oxidized by nitric acid to give the species [TiL]NO₃. The complexes [TiL] and [TiL]NO₃ show differing solid-state electrical conductivity properties.