Structure, Optical, and Magnetic Properties of (PPN + ) 2 (C 70 2− )⋅2 C 6 H 4 Cl 2 , which Contains Dianionic Polymeric (C 70 2− ) n Chains

A new salt, (PPN + ) 2 (C 70 2− ) ⋅ 2 C 6 H 4 Cl 2 ( 1 ), which contains C 70 2− dianions, has been obtained as single crystals (PPN + =bis(triphenylphosphine)iminium cation). The C 70 2− dianions form polymeric zigzag (C 70 2− ) n chains, in which the fullerene units are bonded through single CC bonds of length 1.581(5)–1.586(6) Å. The distance between the centers of neighboring C 70 2− units is 10.441 Å. The optical and magnetic properties of (C 70 2− ) n have also been studied. Decreasing the symmetry of C 70 in the polymer activate about 20 new IR bands in addition to the 10 IR‐active bands of the starting C 70 . The polymeric structure shows absorptions in the visible and NIR regions, with three main bands at 890, 1200, and 1550 nm, instead of one band of isolated C 70 2− dianions at 1165–1184 nm. We concluded that the (C 70 2− ) n polymer was diamagnetic, with a negative molar magnetic susceptibility of −3.82×10 −4  emu mol −1 per C 70 2− dianion. The polymer is EPR silent and a weak narrow EPR signal in salt 1 is due to impurities, which only constitute 0.84 % of spin S =1/2 of the total amount of fullerene C 70 .