Characterization of the bismuth(III) bromide–[2.2]-paracyclophane (2/1) adduct

Abstract

The 2 : 1 charge-transfer molecular complex between bismuth bromide and [2.2]paracyclophane has been prepared and investigated by means of thermogravimetric, electronic and IR spectra and resistivity measurements. The X-ray structure was also determined: monoclinic, space group P2₁/c, a= 7.896(3), b= 14.198(6), c= 10.803(8)Å, β= 101.27(5)°, Z= 2 and R= 0.0457. The structure is built up by polymeric linear chains of BiBr₃ units interlayered by centrosymmetric hydrocarbon molecules. Two bromine atoms bridge adjacent metal atoms so that the co-ordination is very distorted octahedral with three short [2.595(3)–2.676(3)Å] and two longer bridging [3.325(3), 3.402(2)Å] Bi–Br bonds; the sixth site is occupied by a benzene ring of the [2.2]paracyclophane molecule. The complex shows high stability and characteristic electrical properties of a semiconductor at 25 °C.