Donor‐Acceptor Complexes of Tellurium Polycationic Clusters with Cyanogen

The reactions of cyanogen with Te 6 [AsF 6 ] 4 and Te 4 [AsF 6 ] 2 in SO 2 solutions yield Te 6 [AsF 6 ] 4 ·1.5C 2 N 2 ( 1 ) and Te 4 [AsF 6 ] 2 ·C 2 N 2 ( 2 ) as red crystals in quantitative yield. The complexes 1 and 2 are also generated in moderate yield by the reaction of Te, AsF 5 and C 2 N 2 in liquid SO 2 , but by‐products are formed. These reactions show the ability of cyanogen to act as a donor towards tellurium polycations. In the crystal structures, discrete octahedral [AsF 6 ] – ions are present and linear cyanogen molecules, which coordinate the tellurium atoms of the polycations η 2 by both nitrogen atoms. In the crystal structure of 1 , the trigonal‐prismatic Te 6 4+ clusters are bridged by cyanogen molecules to one‐dimensional zig‐zag chains. The crystal structure of 2 contains square‐planar Te 4 2+ clusters, which are bridged by cyanogen molecules to two‐dimensional sheets. The complexes 1 and 2 represent the first chalcogen polycationic cluster compounds containing a nitrogen ligation. The new compounds are unstable with respect to loss of cyanogen but stable under an atmosphere of C 2 N 2 . The Raman spectra of 1 and 2 were investigated and assigned. A serviceable and convenient way to handle air‐sensitive and cold liquids by a transfer needle technique is described.