Two Phtalocyanine Units 'Stapled' by Carbon-Carbon  Bonds in a New Sandwich-type Molecule: {5,5';19,19'-Bi[phtalocyaninato(2-)]}titanium(IV). Synthesis, X-Ray Crystal Structure and Properties

{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.