HEAVY-METAL PI-COMPLEXES .4. SYNTHESIS, PROPERTIES AND CRYSTAL-STRUCTURE OF RED C5H5BICL2 - CHAIN POLYMER WITH HAPTITATIVE DISORDER OF PI-BONDED CYCLOPENTADIENYL LIGANDS

Red thermolabile, light sensitive C5H5BiCl2 has been prepared from NaC5H5 and BiCl3 at low temperature. The crystal structure of the red compound has been determined by single crystal techniques (P21/c; a 680.7(7), b 1441.9(9), c 823.4(6) pm, β 111.25(9)°, T -20°C, Z = 4, R = 0.048). It is built up of distorted TcCl4-type polymeric chains with the Cp-rings π-bonded to bismuth. Pseudorotational disorder attributable to packing requirements results in a mixture of η2- and η3-bonded states (1/1) along the chains. Important distances: BiCl: 258, 264, 309, 318 pm; BiC: 247, 248 pm (η2), 238, 261, 264 pm (η3). Bond length-bond strength considerations show the bond order of BiCp bonding to be ∼ 1.5. In solution the compound is monomeric and according to 1H NMR results a fast rotation of the Cp ring is present even at -70°C. © 1990.