HEAVY-METAL PI-COMPLEXES .9. THE CHAIN POLYMERS 1-INFINITY[(1,2-(CH3)2C6H4BICL3)2], 1-INFINITY[(1,3-(CH3)2C6H4BICL3)2] AND 1-INFINITY[(1,4-(CH3)2C6H4BICL3)2]

In the crystal structures of the three solid state complexes (C6H4(CH3)2)BiCl3 (C6H4(CH3)2 = o-xylene: 1, m-xylene: 2, p-xylene: 3) quasi-dimeric units of almost undistorted, arene coordinated BiCl3 fragments can be found that are further associated via additional Bi-Cl contacts to form one-dimensional polymeric chains. Whereas the chains of 2 and 3 are constituted by Bi2Cl2 four-membered rings only, further Cl-bridging in 1 leads to additional trigonal-bipyramidal arrangements with Bi atoms exhibiting coordination numbers of 3 + 3 + 1 and 3 + 2 + 1, respectively (prim. + sec. Cl contacts + arene). The arene-metal bonding is characterized by Bi-arene distances in the range from 297 - 306 pm, including ring slippages of 24 - 41 pm and 73 pm with the Bi atoms being six and seven coordinated, respectively . The direction of this slipping with respect to the arene's methylation sites cannot be understood in terms of electronic influences but is shown to be caused by steric demands. The values IP1 of the arenes prove to determine the colours of the complexes.